Kodak #18a UV Filter Curve

Related Links:
Archeology Forgeries detected with UV
Art Zone UV Pages
Band-Pass Filters [11/2002]
Black Light Fluorescence Primer (RIT FAQ #29.5)
Fumio Yokozawa's New False Color Technique
  for the Ultra Violet Photograph [book for sale..]
Color UV Photography
Digicam UV (BG-12 filter..) [11/2002]
End of the Beginning Nikon D1 and UV (Bjorn Rorslett)
GIF on UV Setup (police)
Hank Hogan's UV Photo site (neat!)
Longwave UV Photography (of butterflies)
Medical UV Photography
Nikon 105mm UV lens (Cameraquest, URL thanks to Bill Brickell)
Optical Glass Mfgers (addresses of quartz optics makers...)
Pinhole Pages (Clint O'Connor) [9/2000]
Police Photography (link from WJM)
Tips About UV Light Exposures
UV and Fluorescence Photography S.A. Smitherman
UV Applications Handbook (water plants)
UV Art Photography for Restoration (Chartres example)
UV Bulb Info (link from WJM)
UV Flourescence Photography (police..)
UV Lenses Tips (old enlarging lenses..)
UV Mineral Photography
UV Photo Basic Instructions (police)
UV Photo Materials (film, filters, UV curves..)
UV Photography (Eliadis)
UV photography of skin damage (Faraghan Medical)
UV Tips Page

Introduction

Chances are very good that you can shoot ultraviolet light photographs with your current camera(s), some low cost older lenses, and standard color or B&W; films. You probably just need to add a UV-Bandpass filter, which blocks visible light but passes ultraviolet light to the lens and film. The new cost of such filters varies, but range around $50+.

The trick is to pick older lenses from the 1960s and 1970s which were made with older adhesives (like balsam). The more recent zoom and fixed lenses (of the 1980s on) use adhesives which block UV light. So older and cheaper lenses are better for doing UV photography. There are millions of older lenses and cameras that can be used to do longwave ultraviolet photography.

Even if you have the latest model cameras, you can probably use some UV-compatible older lenses simply by buying a T-mount lens for your camera. Total cost of T-mount for your camera, and an older lens to go with it, will often be under $50 too.

Do you already have some older fixed focal length lenses and a camera from the 1960s or 1970s? If so, chances are you just need the UV bandpass filter to get started taking UV photographs!

Commercial UV Lenses

I first learned of ultraviolet photography from some late 1970s booklets by Victor Hasselblad Inc. touting their special 105mm ultraviolet Zeiss Sonnar lenses. UV photographs had the capacity to reveal repairs to artworks as well as fakes. In some cases, underlying images could be revealed, showing figures now painted over by the master artist. Ultraviolet photography also had uses in forensic and criminal evidence photography.

Unfortunately, the cost of these special UV capable Zeiss lenses were way beyond the pocketbook of most citizens, let alone a graduate student. Even the 105mm f/4.5 UV Nikon and 85mm UV Pentax special UV lenses for 35mm SLRs were exceptionally expensive. Kodak had special ultraviolet sensitive films and filters for ultraviolet photography too. That's where matters stood until I came across a fascinating tid-bit while exploring Willem-Jan Markerink's great photography site (see links above).

Longwave UV Photography with Uncoated Glass Lenses

Biologist and photographer Bjorn Rorslett revealed that one could do UV photography, at least in the long ultraviolet range, using simple lenses and inexpensive films. The trick was to use uncoated or single-coated lenses, rather than today's multicoated lenses and filters. These uncoated earlier lenses were quite capable of imaging UV light. Moreover, most camera metering systems could also respond to UV light, as well as most handheld lightmeters.

There were inexpensive consumer films such as tungsten color film from Fuji which responded well to ultraviolet light. Many films can be used for ultraviolet light photography (although Kodak films are not recommended). Most films have some degree of sensitivity to blue and UV light, which is one reason UV filters and haze filters are necessary. Some subsequent research has revealed that these UV photographic potentials have long been known, but just not well advertised (hence, one of the purposes of this page).

Russ Kinne discussed ultraviolet photography in his The Complete Book of Nature Photography (pp. 184-5, Ziff Davis N.Y. 1962).

Kinne noted that quartz lenses are needed below 3650 angstroms, but that uncoated lenses could be used in this long ultraviolet region above this value.

One practical issue regards which uncoated glass lens designs will work best for longwave UV photography? The short answer seems to be the less glass, the better the results. Many four element lenses that are Tessars and related derivative optical designs seem to work well in many cases. These lenses have thin glass elements, with some elements often only a few millimeters thick, rather than the thicker elements frequently found in some other lens designs.

Sorry to say, but many of the more complex designs such as found in ultrawide angles are often poorer candidates for longwave UV usage than the typical simple telephoto lenses. Similarly, complex zoom lenses with many elements, some quite thick, are also unpromising candidates. The simpler prime lenses in the short telephoto and normal lens ranges seem to work surprisingly well, probably for reasons related to the limited amount of thin glass elements employed in their design. But the best answer is to try out your lenses, especially primes, with your UV-pass filter to see if they have "the right stuff".

Bob Shell (noted photographer and editor of Shutterbug) makes the observation that many modern lenses are made with UV cured adhesives (see postings below). The use of these modern adhesives may explain why many modern lenses don't pass UV light well. Presumably, the UV cured adhesives absorb UV strongly.

The quote below highlights the shift to UV absorbing adhesives starting about 1965 in Leica lenses. Again, this observation suggests that Leica lenses (and other brands) from prior to the mid-1960s would be better candidates for longwave UV lens use than the later lenses (with UV absorbing glues and adhesives).

Using ultraviolet light, you also get a focus shift, as with infra-red light. But, as you might expect, that focus shift is on the opposite side of your lens focusing scale. Assuming you focus normally, you will have to increase the lens-subject distance to get a sharp image with ultraviolet light.

How much shift depends on the lens and degree of magnification used, if doing closeup work. For a typical lens, a focus shift of 12 to 18 inches might be expected when shooting an object ten feet away.

Many UV light sources such as fluorescent UV "black light" and true UV bulbs are available. Some of these longwave UV bulbs are used in portable setups for geological prospecting. Be very careful with UV light sources in a studio or other setup. UV light can be irritating and dangerous to your eyes and skin, especially in the shorter wavelengths (e.g., the short UV "germicidal" bulbs, often used in UV EPROM erasers).

While exposure meters are often very sensitive to ultraviolet light, you will have to individually calibrate them by performing a series of hands-on tests. You can take some bracketed shots with your UV setup in daylight to calibrate your lens and filter with your film's effective speed in "sunny 16" daylight. Putting your UV only pass filter in front of your hand-held light meter may also allow you to calibrate it. Exposures tend to be long, as UV light levels are low to begin with (circa 5-10% of visible light levels) and UV film/camera system efficiencies lower too. Even when you get a UV exposure guide based on your test shots, bracketing is recommended!

In any case, please feel free to EMAIL me to share your experiences with us too!

Good luck!

Most modern glasses, such as high index crown and flint materials, do not transmit any ultraviolet. It is all absorbed in the front elements of the lens. Secondly, air itself does not transmit UV below about 3000 Angstroms. This wavelength marks the lower end of the so-called "near ultraviolet".

Not long ago, Zeiss made Hasselblad UV lens for moon astronauts down to 2400 Angstrom, "to insure as many exposures as practical, the film used consisted of a thin base with an UV sensitive emulsion and a special thin coating on top to prevent gas trapped in the emulsion surface from coming out in the vacuum at the moon and possibly causing bubbles in the emulsion surface."

These lunar UV exposures revealed some useful new data on the moon. Today's lenses are at 4,300 Angstroms, the border of visible light, mainly for making integrated circuit chips.

Source: Modern Photography, November 1982, p.10-12, Techniques Tomorrow by Bennett Sherman.

From: karl@mountain-mall.com (Karl Snyder)
Newsgroups: rec.photo.equipment.misc
Subject: Re: Filters as clear lens covers - opinions?
Date: Fri, 11 Sep 1998
...

Filter          UV Light Absorption
UV              22%
Sky 1A          45.5%
UV 15           81%
UV 16           86.5%
UV 17           97%
Haze 2A         Virtually all UV light
[Source: B&H;'s "The Professional Photo SourceBook", page 360, Tiffen Filters.] 
...

Kodak on UV Cameras and Lens Options

pp. 40-41, Infrared and Ultraviolet Photography, Kodak Publication #M-3 (1961) 7th edition.

Ed. note: the yellow color referenced above may refer to use of high refractive index specialty glasses made of thorium salts (see radioactive lenses) which I presume block UV radiation. Again, this suggests that specialty glasses in APO and ED lenses may be problematic for UV use at 365nm. On the other hand, Kodak is also suggesting than nearly any other glass lens from this period (1960s) should work for longwave UV photography too!

Another interesting point is that the flarey nature of some reflected UV photos may be due to fluorescence of the lens and lens cement, which might be prevented by proper lens shades per this article. Conversely, the slight focus shifts needed when using just UV light may also explain some of the soft-focus effects being seen with UV only photography (e.g., flarey fashion photos).

Edmund Scientific's Quartz Lenses for UV Photography

Edmund Scientific's Industrial Optics catalog (N001A) lists some modest cost UV lens options you may want to consider. Call them at 800-363-1992 or request a catalog online at www.edmundoptics.com. Check out the UV quartz lenses on pages 36-37, most of which are shown in the lens table below. Note that I haven't shown prices for the BBAR coated lenses (which reportedly work into the UV without loss to the coatings and with reduced reflections, for roughly $10-20 more per lens). These quartz UV optics exhibit a flat response curve of 90% transmittance from about 200 nanometers (!) to beyond 1.5 microns, with peaks and valleys beyond that to about 3.5 microns. In other words, shortwave ultraviolet light is well within their range, but they encompass the entire UV and visible light spectrum and into the infrared too.

These UV lenses are made of UV grade fused silica with a design wavelength of 588 nanometers (N=1.45848). Four types of lenses are offered - plano-concave (PCV), double-concave (DCV), plano-convex (PCX) and double-convex (DCX). Naturally, you can combine several lens elements to make your own multi-element quartz UV optics. On the other hand, a single double-convex lens could act like a simple plus diopter lens or magnifying glass to image UV subjects onto film.

Naturally, such a single element lens would exhibit certain optical aberrations. Many of these aberrations would be reduced by simply stopping down, perhaps using a Waterhouse stop (metal disk with hole in it) or variable stop mechanism. Eliminating other aberrations would require adding additional elements, presumably using some of the standard optical designs. Some optical textbook formulas and readily available optical design software (some free online) could be used to optimize a design for a given project or requirement.

Single element plus diopter lenses have been used as soft portrait lenses. For an example, see soft focus lenses such as Sima's and Spiratone's 100mm lenses. Note that a focal length of 100mm corresponds to +10 diopters, while 200mm focal length is +5 diopters, and so on (see Diopter Lenses). These single element portrait lenses suffer from a degree of lens aberrations that yields a softer, slightly ethereal image - but only when used wide open. Stopped down, these same simple lenses end up being surprisingly sharp. Similarly, the single element glass lenses used in older Kodak brownie and low cost point and shoots yield highly usable family photographs especially when used stopped down around f/16.

I am not suggesting that the results from a single element convex lens will rival the resolution of modern multi-element lenses. But they might work well enough for many scientific and artistic projects, especially if only modest enlargements are planned. If you need very sharp images, you have to go to multi-element lenses to get them. But if you can live with a single element UV lens, you can explore shortwave ultraviolet photography for under $100 US!

These quartz elements are only about triple the price of similar individual glass elements. Even if you bought four elements to build up a more complex lens (e.g., tessar formula?), you would still be looking at around $325 US for a one inch diameter UV lens (say, a 100mm f/4). Compare that to $3,000 for a UV nikkor or similar 35mm lenses, when you can find them. Sure, the nikkor will be much sharper and better corrected, and more convenient to use. But having never seen one for sale, in thousands of nikkor used lens price listings, you might have to consider rolling your own, perhaps with the help of an amateur optician or telescope maker?

The mechanics of building a simple UV lens using a plus diopter lens could be very simple. A double convex 100mm lens of one inch diameter is under $80 US. You need a manual exposure 35mm SLR to provide film transport and focal plane shutter functions. You might be able to use the internal light-meter, with a filter, after some testing with each film in similar lighting conditions (e.g., bright daylight). To mount the simple lens, you could use a bellows to provide the focusing mechanism and camera bayonet mounting. You would need either Waterhouse stops (metal disks with a different hole size for each f/stop) or a variable f/stop mechanism from a junker lens. Add the right UV sensitive film and a UV pass filter such as a Kodak #18a and you are in business.

In fact, you might be able to use the right (100mm macro?) junker lens for its camera body mounting, focusing helix, and variable aperture mechanism. Just remove the glass, and mount the 100mm focal length UV lens precisely 100mm from the focal plane (indicated by a mark on the camera body top). Or use W.J.Markerink's table of lens registration distances to measure directly from the base of the lens mount.

Now your UV lens can focus to infinity. Twist the focusing helix, and you can get closer subjects. While you will be able to focus normally looking through the lens in your SLR viewfinder, the exact focusing point for shortwave ultraviolet light may be slightly offset from the results you set using visible light to focus. Some experimentation and note-taking will help provide the correct offset to get optimal sharpness offsets needed when you switch to ultraviolet only photography.

At the other extreme, double convex lenses are symmetrical, so they perform relatively well (for a single element lens, anyway) at 1:1. That's a hint if you want to try the simple UV lens for macrophotography. In this case, a bellows mounted UV quartz lens would be a simple way to experiment with this approach. Don't expect a great flat-field response - for that you need a true macrolens design. But the results may be usable if you are imaging nature subjects closeup, typically in the center of the field.

If you already have a plus diopter lens kit, you can use it to try out some of these ideas at minimal cost before investing in a pricey quartz optic. If you don't have the needed plus diopter lens, you can often buy some plus diopter glass lenses of the right strength (+10 = 100mm, +5 = 200mm, +2= 500mm..) on EBAY or other used lens dealers for $5 US and up. The results you get with a 100mm or +10 diopter lens on a bellows, with homemade Waterhouse stop(s), will be similar to what you will get with the same strength UV quartz lens - except the UV lens will also image ultraviolet light! You can also try out the macrophotography and closeup factors, if you have enough bellows extension (or combine extension tubes and bellows to get longer reach). Before you invest $75+ US in a single quartz lens, you should try out these ideas with a low cost (under $5) similar glass diopter lens to be sure the results can meet your needs.

I might add the observation that smaller quartz lenses cost very nearly the same as the larger one inch lenses, while the two inch diameter (50mm) lenses cost more than twice as much. So if you can live with the one inch diameter optic, you will have the most economical size. A one inch +10 diopter (100mm) double convex lens corresponds to a 100mm f/4 lens used wide open. A 200mm focal length lens (+5 diopter) would be f/8, which is rather slow, but perhaps useful if you need the telephoto coverage (on 35mm).

On the other hand, a 50mm focal length corresponds to +20 diopters, and frankly the optical aberrations are likely to become much worse as you go towards higher plus diopter numbers or shorter focal lengths. I would also have concerns about adequate coverage on 35mm - even 100mm might be marginal wide open but improve when used stopped down both in sharpness and coverage. Coverage increases with long-focus telephoto lenses (that is a hint for medium format fans) but many subjects will be less convenient to photograph if a longer, dimmer lens is used (200mm f/8). In other words, the choice of 100mm for the UV nikkor, and 85mm for the UV pentax lenses, is not accidental.

Aside: Mirror Lenses for Shortwave UV

A mirror based optical system would avoid the need for expensive quartz elements. Start with a common paraboloid mirror and reflecting front surface mirror (optically flat) from astronomy surplus. You have an easy to use, low cost, low magnification optical system that works as well in shortwave UV as in visible light. Be sure that the mirror protective coating (if any, such as silicon dioxide commonly) doesn't block shortwave UV efficiency.

Naturally, you would need a UV tranmitting filter (which cuts or absorbs IR and visible light). Such a filter could go either on the front of the telescope or where the eyepiece normally fits. Unless you have a simple quartz lens eyepiece available [possibly using quartz-halogen bulb element(s)?], it would be easier to use direct image projection. If you already have a reflecting telescope with removable eyepiece and T-mount camera adapter, you just need the UV-pass filter and the right film.

In simplest terms, the paraboloid shape of the front surface astronomical mirror brings the parallel light rays from the subject to a single focusing point - just like a lens. But the big advantage of mirror telescopes is they are achromatic, and don't cause color effects which most low cost glass objectives and eyepieces do in refractor telescope designs. We use the mirror's ability to reflect shortwave and longwave UV and bring it to a focus to replace expensive quartz optics needed to prevent absorbing the UV (as would happen with shortwave UV and most glass lenses). Again, since we can simply use uncoated lenses for longwave UV, this trick is likely to be mainly useful where you need shortwave UV imagery.

As an aside, I will add that I have read that silver mirrors are not as useful for some UV photographic applications, compared to the now more common aluminized mirrors. Evidently, the thin silver coating acts more like a filter and may pass some or most of the UV rather than reflecting it. I haven't tested this statement myself, but you might want to be aware of it if you are using a silver based mirror for UV.

F/238 Pinhole - Pool view - TMax 400, 15 secs thanks to Clint O'Connor - His First Pinhole Photo!

Aside: UV Pinhole Cameras

There are no lenses to cause problems with a pinhole camera, so you just need a UV-pass filter and your film. No need for expensive quartz lenses! Instant, ultra-low cost shortwave or longwave ultraviolet photography. You can even build wide angle or telephoto pinhole camera designs, although the telephoto designs require really long exposures.

The stunning first pinhole photo taken above by Clint O'Connor is a great example of what can be done with a pinhole camera and a static subject! While pinhole cameras are usually dismissed as being too fuzzy, you can see that the results can be surprisingly sharp and usable for many purposes. See Pinhole Cameras pages for more ideas.

Aside: Ultra Low Cost Quartz Lenses from Quartz-Halogen Bulbs

The quartz in quartz-halogen refers to the bulb being made of quartz, and most lighting bulbs have some sort of lens crafted in them. Yes, I know these are single element lenses which weren't designed for photographic purposes. But they are lenses, and they are quartz, and they should have extended response in the ultraviolet range.

You can remove (bust out) the lens element and use a Waterhouse stop. A Waterhouse stop is simply a metal disk in which a small central hole has been cut or punched. Simply locate the lens so the Waterhouse stop is aligned with the center of the lens. The Waterhouse stop is acting as an aperture or f/stop for the small quartz lens element. By stopping down the lens, you can minimize aberrations and edge related distortions.

Such a simple quartz lens mounted in a brownie camera or the equivalent with a long duration (bulb or Time) shutter option makes a very cheap, very simple ultraviolet light camera for shortwave as well as longwave ultraviolet. Simply use the appropriate UV-pass filter and light source.

Hopefully, the stopped down quartz lens should yield substantial improvements in sharpness over the lens-less pinhole camera approach. Using a 120 film brownie style camera also permits using less enlargement to get a better quality image. Because the 120 film is 2.2+ times the size of 35mm film, you should get better results with the larger film format. And since you are using a lens and stop setup, your exposure times will be much less than with a pinhole camera with UV-pass filter.

Summary

Related Postings

I am about to embark on some experiments using an ultraviolet light source to detect otherwise unseen repairs etc in pottery and other archaeological material. Being a photographer of very elementary skill- (thank you Mr Canon for the automation that has made my pix so far look ok) - my immediate thoughts are (1) get a good lens for shooting closeup- the items may range from 1 to 30 centimetres high, but I don't anticipate any microphotography- so what is the optimum lens for my Canon EOS 500?, (2) take the u/v or "daylight" filter off the lens :-) and (3) shoot from a tripod with a long exposure in the dark, so the ultraviolet shows up.

Does anyone have any tips at a more sophisticated level than this for photographing u/v fluorescing objects close-up ??

--
If you are interested in Southeast Asian
archaeology or Buddhist art, please visit:
http://www.archaeology.usyd.edu.au/~hudson/bobhpage.htm

From: Kevin Kratzke mirthmgr@erols.com
Newsgroups: rec.photo.technique.misc
Subject: Re: photographing ultraviolet fluorescence
Date: Tue, 06 Oct 1998

Hi, Bob.

I've been doing some research into UV photography for artistic, not archaeological purposes, but I assume that they go by similar principals.

PLEASE correct me if I'm wrong, as I've found little info on the web that I can comprehend (most of the sites I've found on UV either go over my head with facts and figures, or basically say 'Here's what a UV photo looks like' :).

BUT... at least for my purposes it appears I should invest in a UV passing/Visible spectrum absorbing filter, such as :

KODAK Wratten 18A
CORNING 7-63
KOPP 5840
SCHOTT UG-1
HOYA U-360

Unfortunately for my purposes, these filters are fairly pricey (last time I was actually able to find a US price, it was something like $80 for a 58mm screw-mount filter). But you might want to investigate these for yourself if no one else can give you the information you need. And, please, if anyone does have more information on UV, either online or a recommendation for a hard copy source, I'd love to hear it as well.

Hope this helps! And if not, I hope someone can help me, too!

-Kevin

From: dbureau@mail.island.net (Dominique Bureau)
Newsgroups: rec.photo.technique.misc
Subject: Re: photographing ultraviolet fluorescence
Date: 6 Oct 1998

From your question I think you want to shine a UV scource (e.g. a blacklight) on your pieces and then look at any fluorescence created by the UV. If this is correct the filter you want to use would be the Hoya Y44 (other manufacturers might make a similar one but I don't have their catalogs). This filter will block out the UV and let the fluorescence (which is what I assume you're interested in) through.

I've taken pictures of bones marked with a chemical that fluoresces under UV light. When you shine a blacklight the marker glows yellow. I took the pictures without a filter (because I didn't know about the Y44 at the time). Has to be fairly dark, bracket your exposures. I was using between 2 and 30 second exposures with a 15 watt blacklight as a light source. By using several exposures I ended up with satisfactory results.

Hope this helps,

Dominic,

I have tried, without much success, to do UV photography with modern multi-coated lenses. These pass *very* little UV indeed, so unless you are say in New Zealand or other extremely high-UV areas, there is no need for using a UV filter to eliminate UV-induced haze in landscape photography. On the contrary, a UV filter with lot of dirt on it can seriously degrade image quality.

As David R. commented, a true UV-transmitting lens is needed in order to get a good UV image onto film. As I possess one of these quartz/fluorite UV-Nikkors, I also have been able to shoot quite a lot in UV colour. Visit my website for examples of this exciting line of photography. And yes, by putting a UV filter on the UV-Nikkor, I also have a superb macro lens for ordinary photography.

regards
Bjorn Rorslett
Visit http://hawk.foto.no/pinhole/nikon for UV Colour Photography and other Adventures in Nature Photography

rec.photo.equipment.35mm
From: Bjxrn Rxrslett nikon@foto.no
[1] Re: Why UV filters?
Date: Thu Nov 05 1998

> Do you have to take some sort of precaution to make sure you do not damage
> your eyes with the UV rays that get passed through the camera?
>
> | Fumitaka Hayashi      -       hayashi@u.washington.edu     

Focusing the UV-Nikkor 105 mm f/4.5 lens is done using visual light, so UV levels normally are quite low (<10% of incident radiation). No special precautions are needed in this case. The nice thing about this lens is that UV focus and visual focus coincide. Just focus the lens and then switch in a black, UV-transmitting filter before you snap the shutter. No need for refocusing even in the macro range.

However, when I did some experimental work on UV fluorescence I had to wear protective goggles because then the subject was illuminated with a blacklight source and UV levels were high relative to the (dim) visible light. So high in fact that my eyes felt sore for days.

regards
Bjorn Rorslett
Visit http://hawk.foto.no/pinhole/nikon for UV Colour Photography and other Adventures in Nature Photography

rec.photo.equipment.35mm
From: w.j.markerink@a1.nl (Willem-Jan Markerink)
[1] Re: ***Ultraviolet film -where can I get it-
Date: Mon Nov 23 1998

"ahfaye" fayelove@hotmail.com wrote:

>Does anyone know where I can obtain ultraviolet film in 35 or 120 format?
>Please send response to:
>
>fayelove@hotmail.com

There is no such thing as UV-sensitive films....it's more a by-product of some films that are UV-sensitive by accident. You might want to check some UV notes and links on my homepage:

http://www.a1.nl/phomepag/markerink/mainpage.htm

--
Bye,

Willem-Jan Markerink

Thanks to Bill Brickell for his on-going sharing of tips and information on his UV Photography Projects!

Date: Wed, 10 Mar 1999
From: bill brickell tatandtoo@clarksdale.com
To: rmonagha@mail.smu.edu
Subject: ultraviolet photography

Dear sir,

I too have been using longwave UV photography to an artistic end. I do color as well. Most films have some sensitivity to UV unless the manufacturer has coated it to retard the penetration of UV light.

I have a Contax RTS 3 camera and a multitude of Zeiss and other lenses. My results on black and white films produced good results with short exposures. Color films are different, the exposures with regular glass optics are very long indeed. Quartz lenses produce quicker results, but normally cost 10 times more.

Black and white films have no layers, meaning you can expose the UV sensitive silver halide directly. Color films have dye layers. The yellow layer is the one sensitive to UV and it is controlled by the manufacturer as to it's limits.

UV intensity is an issue too. A few places don't have very high UV indexes, the light is there but not in very high intensities.

Hassy's UV sensitive lens is not easily available, and at $14,000 not on my list of affordable items. Nikon has placed their UV Nikkor on limited availability and it is in the $2,700 to $3000 range.

I have taken my 50mm Zeiss 1.4 planar and produced very good images on Fuji RTP, although the exposures are quite long. Since black and white films can be calibrated in stops, a 6 stop increase is indicated, so a UV speed index can be assigned. This won't work with optical glass lenses and color films, 6 stops just produces gross underexposure.

Experimentation is necessary to gain the proper exposure. I have produced good exposures on Kodak 64T and 320T but they take even longer.

Bill Brickell

tatandtoo@gmi.net

Bill added these notes in a followup email:

[Ed. note: Note new email address tatandtoo@gmi.net]
Date: Sat, 20 Mar 1999
From: bill brickell tatandtoo@gmi.net
To: rmonagha@post.cis.smu.edu
Subject: uv photography

Dear Robert,

Thanks for posting my uv experiences on your page. I currently use the Hoya u-360, the Schott#403 and the Kodak 18a for my uv photography. I have also experimented with un-coated lenses. They work ok but the images are slightly soft-focus. Something else I have found, mirror lenses work well; and can produce sharp images. I have adapted a Samyang 500mm mirror lens to the uv spectrum by using a 72mm uv filter, usually the #403 and a 30.5(mm) #4 diopter to shorten the focal length.

Shooting uv with normal lenses based in stops, all of the afore- mentioned filters have a factor of about 80, or 6.5 stops. Since the filters cut virtually all the visible light, any color film you use results in only fractions of it's original ISO. For flash photography, most normal output 100 guide # flashes don't have enough long-wave uv to produce instantaneous exposure. Several flash pops are needed to secure good exposure, and experimentation to get a good idea of exactly how many.

Thanks again for posting my comments,

Bill Brickell

tatandtoo@gmi.net

[Ed. note: Bill contributed these followup observations ;-) ]

Date: Sat, 27 Mar 1999
From: bill brickell tatandtoo@gmi.net
To: rmonagha@mail.smu.edu
Subject: more uv photography

I am in the process of photographing some flowers in longwave uv during the time I'm writing this. At this time the film is Kodak 320t. This film will work, and if over-exposed a stop can be cross-processed in c-41. I usually stand by to explain the yellow negs to the lab, and assure them I really do want them printed. I like to enter these in photo contests to see what will happen. Just a few tech notes: Any uv filter I use for this film,even with the high speed is going to result in very long exposures. Each film you can use, with any of the uv filters,will produce similar but slightly different color patterns on whatever the subject matter is.

All you need to do good uv work is suitable film, some knowledge of your craft, a simple few element lens and plenty of time.

Bill Brickell

Email: tatandtoo@gmi.net

Date: Fri, 03 Mar 2000
From: bill brickell tatandtoo@gmi.net
To: rmonagha@mail.smu.edu

[Ed. note: Thanks again to Bill for sharing these tips and notes!..]
Date: Sun, 14 May 2000
From: bill brickell tatandtoo@gmi.net
To: rmonagha@mail.smu.edu

[Ed. note: thanks to Bill Brickell for sharing these notes and pointers!]
Date: Fri, 4 Oct 2002
From: Bill's email tatand2@ipa.net
To: rmonagha@mail.smu.edu
Subject: Uv photography

Hello,

It has been some time since my last entry and some changes and new ideas have been added to my particular version of ultraviolet photography. I have had much success with a new dichroic "cold " mirror. It does let in some visible light but it is negligible.

I am again using glass optics. I have the Zeiss Planar lenses some of which are 10 or more years old. Kodak says that uv transmission with glass optics ends at 330nm. That is well into the longwave uv range. I use 400 asa film, (black and white). Real b-w film, not chromogenic. I expose it through my Zeiss optics with the Kodak 18A filter at six stops over my regular daylight exposure, align the IR focus mark just as if I was shooting IR film and the resulting image is simply beautiful. No special development of pushing, just t-max developer or x-tol or even d-76 either stock or 1-1.

Now if I want color images, I use 800 asa Fuji film(c-41) and expose through the 18A or the U-360 Hoya, align the IR marks and expose for 2 min at f4. I get Red, white and blue images. The flower is white with a red or orange center for uv signature and the background is blue. It is my dichroic filter that makes this easier and shorter. I simply take 100 asa film and with a full 125 gn flash, expose for 1/15 sec and the resulting color uv photographs are beautiful.

A dandilion, for instance is white, yellow where the uv signature is on a velvety black and blue background. This can be processed at any corner photolab with no expensive lenses to buy or unusual and expensive films with expensive processing.

Uv should be fun, not an addiction. I have checked the specs on the UV Nikkor lens and it has the capability to use uv-b rays, but not with the filter supplied. The uv filters that are available to use with any lens 18-A, Hoya u-360, Schott 403, and the Nikon FF have something in common. THEY ARE GLASS. THERE GOES THE ARGUMENT THAT GLASS WON'T TRANSMIT UV.

Bill Brickell
tatand2@ipa.net

Same Flowers in UV and Daylight
Photo courtesy of Bill Brickell!

Date: Sat, 5 Oct 2002
From: Bill's email tatand2@ipa.net
To: Robert Monaghan rmonagha@post.cis.smu.edu
Subject: uv lenses

Robert,

This is basically for you, I already have this information on the board.

I have a Minolta Autocord TLR camera that I have removed the taking lens and replaced it with UV grade suprasil quartz. This was not a difficult or expensive undertaking. It is corrected for uv, but the exposures are close to the same as glass optics. You have to burn the image onto color film with opaque uv filters.

I am sending the url to information on the Nikon UV 105 quartz lens. It suggests that this lens is for black and white photography and that color images are in monotone blue. I have found that when working with color films and the opaque uv filters, you are no longer bound to F stops. The filter factor of 6 stops with black and white film is correct. It is not however correct for color films. The dye layers and uv inhibitors in the film have to be overcome. This is whether you are using quartz optics or not. It makes sense to believe if you can get perfect exposures on black and white film with glass optics, then, with some exposure compensation, it will work for color films. Two minutes at close range with glass diopters is not uncommon. This is for opaque filters.

If you are interested in shortwave uv you will need a interference filter probably on quartz substrate because it is said that glass will absorb uv light in the 200-300nm range. I have to admit, I haven't personally tried this for myself. I am including a jpeg of visible and uv comparison with my interference filter [see top photo]. This was shot at close range with a 4+ diopter, a full flash and exposure of 1/15 sec at f4 with my 50mm planar lens. This is Fuji 100 asa c-41 color negative film. Developed at a one hour processing lab. I have some of the same pictures done with a Mamiya secor 150mm lens with the same filter and same conditions. This puts uv in the suitable price range for those seeking something fun and not quite so much like an expensive problem.

Bill Brickell
tatand2@ipa.net

[Ed. note: thanks again to Bill for sharing these pointers and humor on shooting UV ;-)]
Date: Mon, 7 Oct 2002
From: Bill's email tatand2@ipa.net
To: Robert Monaghan rmonagha@post.cis.smu.edu
Subject: Re: mailed - Re: Uv photography

Thanks again, Bob. There is not much out there in books about UV photography. I have Fumio Yokozawa's book. I also have a (Kodak copy of their out of print book) UV Photography. It is very helpful in basic set-up. It was long ago decided that simply exposed color negative film (exposed like black and white)would produce a blue toned, monochromatic image. The information on the cameraquest site about the 105uv Nikkor mentions this. There is some information in one of these, but the negatives are thin and yellow. Some labs won't print them for fear of being held responsible, and not getting paid. I have had my experiences with this very thing. I have considered writing a book myself about the long wave uv capabilities of glass lenses, color negative film, and the trips to the one hour photo lab, the look on your face when you see, or kind of see the negatives and the picture tech looking at you like you sure have alot to learn about cameras. Yep, those were the days.

Bill Brickell
tatans2@ipa.net
...

From: Bjorn Rorslett nikon@foto.no
Newsgroups: rec.photo.equipment.35mm
Subject: Re: 35mm lenses for medium format?
Date: Thu, 13 May 1999

Lim Meng Shi wrote:

> >> Given that the camera body is just a light-tight box and the lens
> >> matters most, is it possible to theorectically design such a box with
> >> a focal plane shutter and medium format film backs (135 film on
> >> optional back ?) but using 35mm lens? Will the sharpness be reduced
> >> greatly ? (I guess there could be some chromatic aberrations but maybe
> >> they're OK if the lens is stopped down to the usual MF format
> >> apertures).
> >
> >I doubt it'd fly in most cases.  The best 35mm lenses are made so that the
> >image in a 36mm circle at the film plane is pretty much free of visible
> >aberrations.  When you hear about cheaper lenses that are sharp in the
> >center but have soft corners, exhibit light falloff and such, that means
> >that their "perfect image circle" is significantly smaller than 36mm.
>
> If you pull back the focal/film plane, wouldn't the image circle
> increase? Getting a good image on this plane may be an issue though...

the facts are mixed up here. A typical lens designed for the 35 mm format projects an image circle of approx 43 mm (not 36 mm) onto the film, when it's focused on infinity. Pulling back the film plane will increase the projected image circle. However, concomitantly the front focus will be closer, by the optical conjugate relationship, so magnification in the film plane by definition increases. Many 35 mm lenses can thus be used on a larger format camera for close-ups only, but will *not* focus to infinity. I have used Micro-Nikkors 55 and 105 mm for close-up photography on 6x9 and 4x5" with great success.

However, there do exist 35 mm format lenses which render a much larger image circle than the nominal size needed for this film format. Such lenses can be applied to larger formats. I personally own two of these, viz. Bellows-Nikkor 105 mm f/4 and 135 mm f/4. Both cover the 6x9 format with good corner-to-corner sharpness even at the infinity setting. I have used these lenses for large-format UV photography.

regards
Bjorn Rorslett
Visit http://www.foto.no/nikon for UV Colour Photography and other Adventures in Nature Photography

From Nikon Mailing List:
Date: Tue, 8 Jun 1999
From: Stewart.Long@bcm-ltd.co.uk
Subject: [NIKON] re:UV fluorescence photography

I have at my disposal about 20 UV fluorescent light tubes (black lights), that are 15 watts each for a total of 300 watts of UV light. Although this sounds like a lot of light, it actually is fairly dim, unless the object fluoresces. How should I meter a subject lit by UV light? I don't think a gray card will work because it looks very dark under UV light. Also what kind of films would one recommend?

Rolland,

I have done some UV fluorescence photography as part of my job. I used an F801 and 105f2.8AF micro on a copy stand. Film stock is not critical as you are photograohing visible wavelengths-I used Fujichrome 400 and Fujichrome 100. For exposure, it is best if you can use a spot reading from the fluorescing area as the background is effectively black, but you don't want this to influence the exposures. Bracket 1/2 stop over the meter reading as well. You will find the whole thing easier than you imagine.

A word of caution: UV light sources are dangerous. Wear UV protective goggles or the damage to your eyes can be very real. Avoid prolonged skin exposure to UV also.

Hope this helps,

Stewart

From: delfstrom@usa.net (David Elfstrom)
Newsgroups: rec.photo.equipment.misc
Subject: Re: UV (black light) flash?
Date: Tue, 08 Jun 1999

delfstrom@usa.net (David Elfstrom) wrote:

>Since we can buy fluorescent tubes, commonly called "black lights" that put
>out UV light, to see certain materials that fluoresce, does anyone know  of a
>similar bulb for a flash unit? I can imagine that there might be some
>scientific application for such an action-stopping light source.

Answering my own question: I found a web page at: http://www.algonet.se/~bengtha/photo/rit.edu/ARTICLE_IR_UV.txt

which describes how to convert a regular flash unit into a UV flash by using a Wratten 18A filter.

David E.

From: Bjorn Rorslett nikon@foto.no
Newsgroups: rec.photo.equipment.35mm,rec.photo.technique.nature
Subject: Major UV Colour Update
Date: Tue, 08 Jun 1999

hi everybody

I have performed a major overhaul of the UV Colour Section of my Web site. Go to http://www.foto.no/nikon and select "UV Colour" from the Menu bar. More UV images have been added and there are new pages discussing film alternatives for UV imaging, how colours arise on UV exposures, the use of Infrared Ektachrome (EIR) to record UV Colour images and much more. Navigating the site should be easier than before.

Comments and feedback are welcome.

regards
Bjorn Rorslett
Visit http://www.foto.no/nikon for UV Colour Photography and other Adventures in Nature Photography

rec.photo.misc
From: "peter" pkessler@odn.de
Newsgroups: rec.photo,rec.photo.film+labs,rec.photo.misc
[1] Re: Velvia and infrared light?
Date: Thu Oct 07 1999

 > Hi everyone!
> I couldn't help but notice that Velvia's spectral dye sensitivity
> curves go back up for wavelengths below 400nm.  Is anyone aware of what
> are the sensitivity curves for these wavelengths? Also, has anybody
> tried to shoot Velvia with infrared filters on?
> Any insights would be much appreciated... thanks!
> Andrey
> (please copy your response to: andrey libertybay com -- thanks very
> much!)

sorry, but below 400 nm is ultra-violett, infrared is above 750 nm. Specially color-neg films are sentisized above 700 nm. This can make some strange effects: blue flowers are magenta on the prints. To overcome this, in some films a special filter-layer is buildt-in. All films, b&w; and color are sensitive for ultraviolet light until the gelatine stops the short-waved rays. But normaly in photography the lenses will absorb the short waves. Only when you're using quartz-lenses without any glue you can take pictures with special, gelatine-poor plates, so called Schuhmann-plates.

Peter

[Ed.note: Can anyone help with a reference to other quartz lenses besides Nikkor UV and hasselblad UV-planar? Thanks!]

Date: Tue, 26 Oct 1999
From: Ron Bouchard zoron@unix1.sncc.lsu.edu
To: rmonagha@mail.smu.edu
Subject: UV lens

Hello my name is Ron Bouchard, I work at Louisiana State University and a professor and I are trying to do some photographic experiments using UV light. Unfortunately the lens that we were going to purchase from Nikon is no longer manufactured. I was wondering if there was an alternative. We need to photograph bird feathers under UV light. No feather is longer than 1 inch.

If you know of any quartz lens that is on the market I would very much appreciate the lead.

--
Ron Bouchard
Research associate
Louisiana State University Department of Biological Sciences

[Ed. note: can anyone supply more info in response to this query? Thanks!]

Date: Fri, 5 Nov 1999
From: "Dr. George S. Losey" losey@zoology.hawaii.edu
To: rmonagha@mail.smu.edu
Subject: UV Imaging

I am working on UV vision and coloration in reef fishes. We use an image intensified quartz front CCD with quartz lenses and a series of notch filters for data collection, but it was ridiculously expensive. We need a way to take some less noisey UV shots for publication. I know that some of the CCD camcorders have fairly good UV sensitivity and have gotten some fair video with low-pass UV filter and IR block filter. I hear that the sony HAD CCD is UV sensitive.

Does anyone know of a digital still camera with fairly good UV sensitivity? Has anyone tried the Sony DSC-F505 that has the HAD CCD?

Dr. George Losey
Dept. of Zoology & Hawaii Inst. Marine Biol.
Univ of Hawaii
808 9568619 fax 9569812

Date: Sat, 27 Nov 1999
From: nfoltz nfoltz@mindspring.com
To: rmonagha@post.cis.smu.edu
Subject: Ultraviolet Nature Photography

Hi -

I am having fun with using an Ultraviolet Schott Glass filter and Fujichrome RTP 64 and Kodak EIR E6 processed at ISO 200. I can use the filter in combination with a Wratten #12 for Infrared photography, too.

My web pages are at http://flzhgn.home.mindspring.com/indexc.htm

Hank Hogan

From: chris@somewhere.com (Chris)
Newsgroups: rec.photo.technique.misc
Subject: Re: ultra violet fluorescence
Date: Sun, 16 Jan 2000

>I am trying to photograph the ultra violet fluorescence in rock  samples.  I
>have a 125 W Philips lamp for the UV source in a darkroom.  The camera  is a
>Nikon FE2 with a Medical -NIKKOR 120mm lens.  It has been recommended to me
>to use a Y-44 filter for correction(???).  The exposure time we have been
>using is 20 seconds. The problem we are having is some of the photos are
>very blurred even though the focus seemed to be right when we took the
>photo.
>
>Any help or advice would be greatly appreciated.
>
>Konrad Weiss   

have you added a UV filter to cut out the UV reflectance and pick up the flouresence only???

UV will also focus at a different point to visible light. It is often discribed with respect to Infra-red photography, some lenses even have an IR focus mark, set to one side of the normal focus point. With UV, you need to focus to the opposite side of the focus point from the IR.

[Ed. note: possible sources for quartz lenses in surplus?]
From: "Al" aocc@worldnet.att.net
Newsgroups: sci.astro.amateur
Subject: Re: Seeking Surplus Source for Quartz Lenses
Date: Fri, 14 Jan 2000

Edmund Scientific in New Jersey may be a good source...they also have a web site.

Al

From: "peter" pkessler@odn.de
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Quartz Lenses
Date: Wed, 1 Dec 1999

> Does anyone have information on the names/histories of Quartz lenses? They
> were probably made for Military or Scientific purposes.
> Thanks
> Frank Filippone

Hi,

August Koehler has made microsope lenses from fused silica at the workshop from Carl Zeis 1904. They where monochromates corrected for the wavelenght of 275 nm. Later on some factories have made also lenses for other purposes like forensic and medicine research, e.g. Burke and James in Chicago.

Peter

Date: Thu, 13 Jan 2000
From: yokozawa@hq.hpk.co.jp
To: rmonagha@mail.smu.edu
Subject: UV false color photography

Dear sir,

I am shooting UV photograph from 10 years ago. At first B/W film and UV filter like KODAK 18A are used, but B/W pictures have less information on the spectra of objects so I wish to get the UV color photograph with one exposure. I developed the new FILTER for UV False Color and got satisfying result. The objects are nectar guide of wild flowers and insects, with my technique the objects could be shot as in live conditions at the field.

Could you please visit my home page at http://www2.odn.ne.jp/~cca00630 there are some False Color photographs of wild flower, and please give me any comment freely.

Thanks in advance.

E-mail address: cca00630@pop06.odn.ne.jp

and an update....

Date: Thu, 4 Nov 1999
From: yokozawa@hq.hpk.co.jp
To: rmonagha@mail.smu.edu
Subject: UV Photography

I succeeded to make the UV false color with once shoot exposure. UV nikor and newly developed filter are used. Would you please visit my home page at www2.odn.ne.jp/~cca00630 you can see some wild flowers in the ultraviolet world.

From: tintype@megsinet.com (Peter Mikalajunas)
Newsgroups: rec.photo.technique.nature
Subject: Re: Flowers under blacklight
Date: Sat, 27 Nov 1999

>Thelonious Georgia wrote:
>>
>> Hey all-
>>
>> I just bought a blacklight bulb for a small extra studio lamp that I have on
>> a whim and have been experimenting with it, and was wondering what flowers
>> looked nice under it. Also, does anyone have any preferences for film type
>> when experimenting with a blacklight?
>
>There is a nature photography site- http://www.foto.no/nikon/ where
>there is some UV color photography. The film you use has to be sensitive
>to UV and then you have to filter out the rest with black glass UV filters.

The site mentioned above makes use of the UV-Nikkor 105 mm lens. If you have $3,000+ then go for it. For film try starting with Fuji RTP.

The main problem is the lens. A modern multi-coated lens will not transmit UV in the spectrum of interest.

Take a look at the following sites:

Master site of links, mainly IR and UV.

http://www.a1.nl/phomepag/markerink/mainpage.htm

UV color - nature shots - with an older single coated lens:

http://flzhgn.home.mindspring.com/uv.htm

Peter Mikalajunas

Photo links
http://www.megsinet.com/tintype

Date: Sat, 15 Jan 2000
From: mkharris@mediaone.net (Marshall Harrison)
Newsgroups: sci.astro.amateur
Subject: Re: Seeking Surplus Source for Quartz Lenses

Try http://www.surplusshed.com/

They sell government and other surplus optical supplies.

Marshall

Date: Mon, 14 Feb 2000
From: "Wally Horniak" horniak@borstad.com
Newsgroups: rec.photo.equipment.35mm
Subject: UV Quartz lens

Hi,

Does anybody know where there is anyone of the following:

Takumar UA Quartz 85 mm - long discontinued
Nikkor UV, 105mm, discontinued last year
Haselblad UV - Sonnar 105mm,

Any suggestions for other lenses that are known to be suitable for UV (300-400nm) would be appreciated.

Regards

Wally Horniak
Borstad Associates
114-9865 West Saanich Rd
Sidney BC  V8L 5Y8
250-656-5633
fax: 250-656-3646 
www.borstad.com 

[Ed. note: If anyone can help suggest a shorter focal length lens for Mr. Springer, please let him - and US! - know... Thanks!]

Date: Tue, 09 Nov 1999
From: eliot@vms.huji.ac.il
To: Robert Monaghan rmonagha@post.cis.smu.edu
Subject: Re: quartz lenses

Robert,

Thanks for your reply. The truth is that I'm looking for lenses that will work with shorter UV-between about 254 and 360nm. We have the Nikkor 105mm but it's focal length is very poor for our purposes. We need ideally something about 60mm. I have heard that there is a lense manufactured in China but understand that it's focal length is similar to the Nikkor. If you have any more suggestions where to look, I'd appreciate it.

All the best,
Eliot Springer
Jerusalem, Israel

Date: Fri, 12 Nov 1999
From: Antonio Misiani antoniomisiani@libero.it
To: rmonagha@mail.smu.edu
Subject: informations about uv photography

[Ed. note: with all the uncoated lenses out there, I don't advise removing coating from modern lenses; much more costly than finding an older lens to experiment upon, simply using a T-adapter, bellows, or other mount adapter...]

Date: 30 Nov 1999
From: artkramr@aol.comnojunk (ArtKramr)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Quartz Lenses

>Subject: Quartz Lenses
>From: "Frank" red735i@earthlink.net
>Date: Tue, 30 November 1999 02:38 AM EST
>
>Does anyone have information on the names/histories of Quartz lenses?  They
>were probably made for Military or Scientific purposes.
>
>Thanks
>
>--
>Frank Filippone

I have one of the original Nikkor Apo El lenses and it has one quartz element in it. It is extremely sharp, and is diffraction limited wide open. Originally is cost about $2,000. The later models of this lens did not have the quartz element and they were smaller and liighter than the original model..

Arthur

[Ed. note: be careful using UV light sources!...]
Date: Tue, 30 Nov 1999
From: derek_ayr@my-deja.com
Newsgroups: rec.photo.technique.people
Subject: Re: Blacklight and film advice needed

Woodnu@liketa.no (Raskolnikov) wrote:

> Check all your lenses first - some modern coated optics perform rather
> differently than you'd expect - they block all UV and the near-UV visible
> light involved in blacklight/glow-in-the-dark effects.

According to the text book any glass lens will block UV but that is not the problem. UV light is not being photographed. UV stimulates certain surfaces and causes them to fluoresce with Visible light. It is this which gives the effect wanted. The UV source is the catalyst.

Raskolnikov's practical experiments show that it will be neccessary to experiment with different combinations of lenses and exposure to obtain premium results. I at one time did UV work through microscopes and found colour slide film was excellent at giving good bright colours but the exposure time was oh! so slow!

In the UK there is quite a lot of regulations surrounding the use of UV sources. I imagine this will be the same in many other countries. UV light used incorrectly can cause severe eye damage.

derek_ayr

Date: Mon, 29 Nov 1999
From: zeitgeist greenky.wa@mindspring.com
Newsgroups: rec.photo.technique.people
Subject: Re: Blacklight and film advice needed

You might want to check gemology, rock collectors try to photograph their collections under uv light, there are a lot of special things to consider. the main thing is lenses are not designed to focus or even transmit uv light, and I believe film has uv inhibitors built in as the nature of photo chemistry is to be over sensitive to blue light and the upper spectrum. special lenses that adjust for uv light are very expensive scientific instruments.

how do they photography blacklight effects for all those 60's movies or their retro revivals? I would guess they fake it with makeup and weird clothes.

John wrote:

> Hello to all and happy holidays to all.
>
> I have been searching deja.com and other areas of the net to get some advice
> on shooting models using blacklight for the lighting. I'm planning on  using 
> colored paints and undergarments to get some hopefully interesting effects.
> So I am wondering how much blacklight I should use in a 20'x16'room. What
> filters I should use if any and last but not least what would be the best
> color film to use and its speed for the best quality for 11"x14" prints.
> Thank you for any help.... John

Date: Thu, 02 Dec 1999
From: "Frank" red735i@earthlink.net
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Quartz Lenses

The purpose in asking the question is to ferrett out information on possible enlarging lenss for Platinum or Palladiium printing. These processes require UV light. Glass will attenuate this light to some degree ( I think I remember some huge percentage, but not sure of the amount). Quartz will not attenuate the UV light as significantly. SO Quartz is the product of choice for UV Light.....

Now, having given away the store, let's all get down to business..... Can we find a quartz lens, which was probably made for a military aerial or reconnaissance or space camera?? Name and FL and image circle if possible?

I feel confident that the lenses do exist, and will be mondo expensive for new... but as a used, and probably unknown lens, they will be available.....

--
Frank Filippone

Date: Thu, 02 Dec 1999
From: Helge Nareid h.nareid@eng.abdn.ac.uk
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Quartz Lenses

"Frank" red735i@earthlink.net wrote:

>The purpose in asking the question is to ferrett out information on possible
>enlarging lenss for Platinum or Palladiium printing.  These processes
>require UV light.

What wavelength range are you thinking of here? Also, do you have a suitable light source in mind?

>Glass will attenuate this light to some degree ( I think
>I remember some huge percentage, but not sure of the amount).  Quartz will
>not attenuate the UV light as significantly.  SO Quartz is the product of
>choice for UV Light.....

The material of choice is really the synthetic variety, which is called "Fused Silica" - crystalline quartz does not have very good uniformity. Fused silica is a fairly expensive material, and is (like quartz) more difficult to grind and polish than ordinary glass. There are a few other materials out there with significant UV transmission, such as synthetic sapphire (which is expensive, difficult to shape, and has problems with optical anisotropies).

The other possibility is using an all-mirror lens, which can be used at wide range of wavelengths - and also has the significant advantage of no colour dispersion at all, which can be very useful when you want to focus your lens. I am not aware of any all-mirror lenses which are suitable for enlarging (there are a few all-mirror microscope objectives on the market), but that may well be the best way to go.

>Now, having given away the store, let's all get down to business..... Can  we
>find a quartz lens, which was probably made for a military aerial or
>reconnaissance or space camera?? Name and FL and image circle if possible?

There is also the scientific market, but a casual browse through the catalogues I have at hand doesn't turn up anything in particular. Also, don't forget the photolithography market - shorter wavelengths provide higher resolution.

>I feel confident that the lenses do exist, and will be mondo expensive for
>new... but as a used, and probably unknown lens, they will be available.....

--
Dr Helge Nareid
University of Aberdeen, Department of Engineering
Laser and Optical Engineering Group
http://wwwcad.eng.abdn.ac.uk/~eng529/

Date: 2 Dec 1999
From: Struan Gray struan.gray@sljus.lu.se
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Quartz Lenses

.....

There are manufacturers of UV-pass lenses for machine vision applications, which would give you a broader range of options than the UV nikkors, but they tend to be for 1:10-ish macro applications with CCDs, so they will only work with cropped 35 mm. Quartz or Sapphire lithographic lenses with 10-inch fields and reproduction ratios of 1:4 or so exist and are used for semiconductor manufacture (there's a Zeiss Planar if you like German Bokeh :-), but you'd need an awful lot of disposable income to buy one.

There are also significant safety issues with any UV source that is bright and hard (low wavelength) enough to projection print Pt/Pd in the same way you print silver-based B+W. If will be much easier to fry your eyeballs or give yourself bad skin burns than with something like a blacklight contact frame. Alignment and focussing of a UV enlarger will be tough with light you can't see.

At the end of the day, you will have to work hard and spend a lot of money to beat the quality possible with a contact print from an enlarged neg. A simple UV lens won't be well-corrected enough, and a safe UV light source will make exposure times unbearably long. I'd say wait a while until UV LED's come on the market (Real Soon Now...). Pop one in an inkjet cartridge and you'll be able to write digital files directly to Pt/Pd paper.

Struan

PS: Sapphire is surprisingly cheap these days, and 30 cm diameter single crystals can now be grown. It is non-ideal as a lens material because it is birefringent (different polarisations have different refractive indices). Quartz is similar, and more optically active to boot, which is one reason why fused silica is preferred if those last few nm of transmission are not needed. Various salts like MgF are better in terms of optical properties and absorbtion, but are easily cracked, scratched or eaten away by moisture.

Date: Sat, 01 Apr 2000
From: Del Johnson deljohnson@my-deja.com
Newsgroups: sci.astro.amateur
Subject: Re: UV photography/astronomy

Have you considered mirrors instead of lenses? Mirrors will focus UV and visible light on a common focal plane, making focusing easier.

Del Johnson

Date: Fri, 24 Mar 2000
From: Bob Shell bob@bobshell.com
Subject: Re: [Rollei] Rollei filter on tessars

Bob,

My understanding from talking to lens designers is that this has little or nothing to do with lens coating but is more of a function of the cement used to glue lens elements together in compound elements. Early cements, generally balsam types, are more or less transparent to UV. Later types used in all modern lenses were designed to be UV absorbers, and some companies even hyped this fact when they began to use them.

Bob

>From: Robert Monaghan
>To: rollei@mejac.palo-alto.ca.us
>Subject: Re: [Rollei] Rollei filter on tessars
>Date: Thu, Mar 23, 2000, 6:07 PM
>

> My personal suspicion is that older uncoated and single coated lenses
> pass much longwave ultraviolet light; in fact, that's why I can use some
> older uncoated lenses (135mm f/4 bellows nikkor) for longwave uv
> photography with a UV-only passing filter (such as Kodak #18A).

From Rollei Mailing List:
Date: Fri, 24 Mar 2000
From: Laurence Cuffe Laurence.Cuffe@ucd.ie
Subject: Re: [Rollei] Rollei filter on tessars

>My understanding from talking to lens designers is that this has
>little or nothing to do with lens coating but is more of a function
>of the cement used to glue lens elements together in compound
>elements.  Early cements, generally balsam types, are more or
>less
>transparent to UV.  Later types used in all modern lenses were
>designed to be UV absorbers, and some companies even hyped
>this fact when they began to use them.
>Bob

I think we may have two isues here: the use of UV cure cements in many modern lenses and the isue of UV and antireflection coatings.

If a cemment is U.V curing it is quite plausible that it would also absorb strongly in that wavelength region.

Most specs I've seen for multi- layer antireflection coatings show reflectivity climbing rapidly as you go into the U.V. typical figures say 10% reflectance at 400nm.

A single layer of Magnesium Flouride would do somewhat better under these circumstances at 400nm a typical single layer coating would reflect about 2% of incident light, this would be down from a best performance of about 1% but not dramatically so. For comparison again at 400nm The internal transmittance for three Schott Glasses Bk7, SF11, and LaSF9 would be respecivly 0.998, 0.73 and 0.85 for a 5mm thick sample. (Source Melles Griot optics guide 5) on a practical level I have run into exposure problems with no filter on my Rollei 35 in the Alps at 3000-4000 (trioter lens) meters. This could, however be due to the large amount of snow around or the meter registering inaccurately under these conditions.

The effect was overexposure on slide film and could have have been due to excess U.V.

Larry Cuffe

From: w.j.markerink@a1.nl (Willem-Jan Markerink)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Lens coating question.
Date: Mon, 07 Jun 99

"Ron Walton" Ronk@tima.com wrote:

>>Personally, I like uncoated lenses for the reasons neither of you
>have
>>listed.  They can be used to double my photographic range into
>the long
>>ultraviolet. Only uncoated (or sometimes single coated lenses
>with the
>>right lens adhesives) can be used for long ultraviolet
>photography -
>>unless you can pony up the kilobucks for the UV specialty lenses
>from
>>Nikon ($3k) or Zeiss ($8-15k). By comparison, a $10 uncoated lens
>is a
>>bargain ;-) see http://www.smu.edu/~rmonagha/mf/uv.html for more
>on UV
>>photogr. using older lenses and tungsten films...
>    The reason I asked the question is because I want to try UV
>photography.
>    Do you know if the screw mount Pentax Takumar lenses pass
>enough UV for UV photography?

Here an odd detail, which not many people know: At one time in the (not so recent) past Pentax made dedicated Takumar UV/IR lenses, 2 different focal lengths:

Asahi Ultra-Achromatic-Takumar 1:4.5/85mm & 1:5.6/300mm. Only the first is suitable for UV, corrected from 220nm to 1000nm, the latter only from 400nm to 850nm.

The odd thing is that the Zeiss/Hassy Super Achromat 1:5.6/250mm is not corrected much better than the latter, 400nm to 1000nm....for deeper you need the UV-Sonnar 1:4.3/105mm ("all wavelengths").

Also, below a posting to the IR-list, about an even more interesting UV-lens alternative:

-----
Date sent:        Mon, 8 Mar 1999 09:45:58 -0800 (PST)
From:             Rolland Elliott rolland_elliott@yahoo.com
Subject:          UV photography with Nikkon Enlarging lenses
To:               infrared@a1.nl
Send reply to:    infrared@a1.nl

This post is for everyone who's interested in UV photography!

I've been doing some research about UV photography over the last couple of months, and recently got a true UV filter made by B+W. The only problem is that I now need a lens that will pass UV light (most modern multicoated optics supress UV light substantially, and unfortunately, all of the lenses I own are modern and multicoated.) I though I would have to buy some super old non coated Nikon lenses to use with my camera, but I heard that these older lenses usually are not corrected in the UV range, producing unsharp pictures. However, it looks like Nikon Enlarging lenses might be better than old uncoated lenses for UV photography see below:

Here's some interesting information I picked up from a Nikon Catalog about their enlarging lenses:

EL-Nikkor enlarging lenses are corrected for chromatic aberration beyond the visible spectrum into near ultraviolet wavelengths -- wavelengths to which photographic papers are particularly sensitive. Through the use of special optical glass and matching optical coatings, EL-Nikkor lenses are designed for ultraviolet transmission in the 350 to 450 nm range. This means EL-Nikkor enlarging lenses can be used for color separation in addition to all other enlarging applications. EL-Nikkor lenses are also front threaded to accept screw in accessories , and can be used for exceptional small-object photography when mounted on a bellows.

These enlarging lenses don't have the spectral transmission of a true UV quarts lens, but then again they don't cost $3000 US dollars like Nikon's quartz lens.

My only problem now is to figgure away to mount these enlarging lenses on my Nikon N90s camera. I need some kind of adapter that goes from the Nikon F-mount to a 39mm thread that is deep enough to allow me to turn the lens in and out of the mount for focusing purposes.

I'd appreciated any insight from those who might have tried this.

Sincerely,

Rolland Elliott
-----

--
Bye,

Willem-Jan Markerink

[Ed. note: not an endorsement, but for availability info...]
rec.photo.marketplace.medium-format
From: RMG rmgwhs@dreamscape.com
[1] FS Hasselblad 105mm F/4.3 UV SONNAR
Date: Fri May 12 2000

I have a rare Hassy UV lens for ultraviolet photography. This lens is in excellent condition, and has case and caps. This is an extremely expensive lens, serious inquiries only please. Check my other Hassy equipment for sale at

http://www.dreamscape.com/rmgwhs/Hasselblad/Haselblad.html

Date: Wed, 10 May 2000
From: jszania@safesun.com
To: rmonagha@mail.smu.edu
Subject: UV meters

Hello,

I have seen your http://www.smu.edu/~rmonagha/mf/uv.html

You might be interested in our UV meters, please take a look at:

http://www.SafeSun.com/

http://www.SafeSun.com/optix/ab.html

http://www.SafeSun.com/optix/3600.html

Best regards,

Jack Szaniawski

Optix Tech Inc.
1100 17th Street N.W., Suite 1101,
Washington, DC 20036

http://www.SafeSun.com

From: RMG rmgwhs@dreamscape.com
Newsgroups: rec.photo.equipment.medium-format
Subject: Hasellblad lens 105mm UV Sonnar ??
Date: Wed, 10 May 2000

I have, from an estate sale, a Hasselblad 105mm F/4.3 UV-Sonnar lens. It is in excelent condition, has caps and case,. I can't seem to find this camera in any camera "bluebook". Does anyone know what this lens is? Someone said it may have been a special order. Any idea as to its value?

thanks in advance,
rmg

From: "Q.G. de Bakker" qnu@worldonline.nl
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Hasellblad lens 105mm UV Sonnar ??
Date: Thu, 11 May 2000

"RMG" wrote:

> I have, from an estate sale, a Hasselblad 105mm F/4.3 UV-Sonnar lens. It
> is in excelent condition, has caps and case,. I can't seem to find this
> camera in any camera "bluebook". Does anyone know what this lens is?
> Someone said it may have been a special order. Any idea as to its value?

The UV-Sonnar was introduced 1968. It has not been listed for some years now, but it might still be available on special order.

It is a special purpose lens using quartz and fluorite elements, that, unlike the usual glasses, will transmit short wave length UV-light from 215 nm upwards. It was designed (for NASA i believe) to be used in scientific and technical applications using UV-light, but it can also be used for photography in visible light. It is extremely well corrected for both distortion and colour. Focussing for UV-light can be done using visible light without needing further adjustment.

It is an *extremely* expensive piece of equipment: in 1992 (The last year i can find it listed. CF-version. Cat.No. 104209.) it was priced at about $ 15.000 (fifteenthousand) give or take a couple of thousand dollars...

I'm not sure about this, but i believe that the quartz and fluorite elements are prone to deterioration due to temperature and moisture.

From Hasselblad Mailing List:
Date: Tue, 08 Aug 2000
From: RMG rmgwhs@dreamscape.com
Subject: 105 UV Sonnar

I have a Hasselblad 105 UV Sonnar Lens that i am trying to find some information on. It is a rather hard question, as there seems to be many factors. I am wondering what would be a fair selling price for this lens. I have several people interested in it. I have seen it listed in camera blue books for $15000, one person is sending me a catalog where he says it sold for $4000. Another person said it isn't worth much without a special filter( can't remember the name or number) that came with it.

Here is all i know. The lens is in mint condition, it has original caps and case. Iam selling it for a friend whose father bought it new a long time ago. We are not sure how long ago. It is 105mm f4.3 UV-Sonnar Nr 5771542. It looks like it was never used, however we did have the shutter and apperature checked and tested(not calibrated). Does anyone know of a similar lens that has been sold recently, or a place where i could find more info? thanks in advance for the help!

From Hasselblad Mailing List:
Date: Tue, 8 Aug 2000
From: Paolo Pignatelli paolop@snet.net
Subject: RE: 105 UV Sonnar

The 105 UV Sonnar is made of fluorite and quartz elements, which greatly enhances transmission in the UV spectrum. It is the lens to use when greatest corner detail and highest contrast are needed, such as in scientific and technical work. It is famous in general photography for its distortion correction. The lens has 7 elements in 7 components.

Paolo

Paolo Pignatelli

From Hasselblad Mailing List:
Date: Tue, 8 Aug 2000
From: Eduard Crombie on7ce@freegates.be
Subject: RE: 105 UV Sonnar

I have a June 1977 Belgian pricelist from the former distributor, Prolux. The Zeiss 105mm UV Sonnar C 1:4,3 is quoted at 317,041.- BEF.

As a comparison, the Zeiss 80mm Planar C 1:2,8 T is quoted at 28,241.- BEF. Prices _without_ 25% VAT.

Richard Nordin ("The Hasselblad Compendium") estimates that only 100 were built in a period of 15 years.

HTH.

Eduard Crombie
Dendermonde, Belgium.

From Hasselblad Mailing List:
Date: Tue, 08 Aug 2000
From: RMG rmgwhs@dreamscape.com
Subject: Re: 105 UV Sonnar

i did put this lens on ebay. the bidding stopped at $3400. Since we are not in that much of a hurry to sell it, i thought i would try other avenues. the owner's father who bought this, was a scientist. his daughter, for whom i am selling this, would be willing to sell it well below $15000, especially if the user had a scientific use for the lens. However we are willing to wait for someone who can appreciate its value , and knows a good deal when it comes around.

From Hasselblad Mailing List:
Date: Tue, 08 Aug 2000
From: Mark Rabiner mark@rabiner.cncoffice.com
To: hasselblad@kelvin.net
Subject: Re: 105 UV Sonnar

Richard Avedon in the very Early 80's did a series of Vogue Covers and editorials of Brooke Schields with what appeared to be black light. My guess at the time was that he did it with this lens. It also looked like it was run through the press an extra time for an extra blue. Or all or none of the above.

Mark Rabiner

Date: Fri, 11 Aug 2000
From: LEO WOLK bigleo@worldnet.att.net
To: hasselblad@kelvin.net
Subject: Re: 105 UV Sonar

This is perhaps a rational approach to pricing this lens, but not a realistic one, based on my own experiences. The 24mm f3.5 Distagon is considerably RARER than the 105 UV Sonnar, it was made for an equally specialized application, and I'm sure it certainly didn't cost ANY LESS than the 105 when they were basically CUSTOM MADE. A couple of years ago KEH had two 24's for sale, the lesser of which (E+) was priced at $4500 (it was marked down from $7000). I KNOW this for a fact, because I seriously considered buying one at the time. If KEH, with their extensive ability to market a specialized item like this (certainly more than anyone on this list could hope to acheive) was selling the 24 for $4500, then it seems unlikely that the 105 would be worth any more.

Remember, the 105, even though it was "special order" was still a catalogue item. The 24 was strictly "custom made" by Zeiss! Even the thought of having anything custom made by Zeiss makes my credit card warm!

Just my 2 cents worth, Leo.

>I've done a little checking.  The new price today for the 105 UV
>Sonnar is $15,000 US.  The lens has such little traffic on the used
>market that it is not even listed in the Blue Book of used photo
>equipment.  But a fair market price today, even for a minty, older
>lens of this type, would be around $7000 to $8000 US (about half the
>new price) according to those who deal in used equipment daily, I
>talked to.

From Nikon MF Mailing List:
Date: Thu, 17 Aug 2000
From: Dag Altin Dag.Altin@chem.sintef.no
Subject: Re: Lens coating..

sturk@telerama.com wrote:

>    I just gotta ask - WHY do you want to remove the lens coating?
>    The least expensive and easiest way might be to find a older uncoated
>lens to use instead.

The reason why is to be able to broaden the transmittance of the lens into near UV-light, preferably as far down as the glass permits. Yes, I am aware of the quarts-fluorite based 105mm UV-nikkor, but this is out of budget at present. But for uncoated Nikkors, how far back in time do we have to go to find them, and still not have to fight collectors at e-bay to get them? Preferred focal length is approx. 50mm, so my present aim is at a single coated 50mm f1.8 series E, and modify from there. Hm, anybody got some fungus to share... (sorry, couldn't resist it).

Best regards, Dag Altin - Mid Norway.

From Nikon MF Mailing List:
Date: Thu, 17 Aug 2000
From: "Stu Turk" sturk@telerama.com
Subject: Re: Lens coating..

.....

The lens for my first F, purchased in the late 60's was single coated so I would think one from the mid-1960's would work. If you do not need to focus the lens at infinity you might check and see if anyone still makes (or if you can find a used one) bellows that uses 'T' mount adapters. If you can find one you can use a Nikon adapter on the camera end and the adapter for whatever uncoated lens you can find in a camera store's discarded bin on the front of the bellows. Should be dozens of old T mount or Pentax screw mount lens around. :-)

As for removing the coating, I can suggest a easy (but disgusting) method: one of my ex-partners was using my Contax RTS with the 85mm Zeiss lens for some tabletop photography and decided to clean the lens with compressed air. He didn't know not to tilt the can downwards. Some of the propellent chemical squirted out and did a #$%! excellent job of removing the coating in the center of the lens. :-(

Stu Turk, Pittsburgh PA USA
sturk@telerama.com

From Nikon MF Mailing List:
Date: Sat, 19 Aug 2000
From: Robert Monaghan rmonagha@post.smu.edu
Subject: re: uncoating and UV photography

the real problem is more likely to be the modern adhesives in current lenses are UV cured in many cases, and absorb UV much more so than the glass lens elements themselves. So the lens multicoating is more an indicator of the type of lens adhesives used, and their absorption of UV, than a real cause of the problem. After all, a single coating is 95% effective, and multicoating only raises that to 98% or so effective, so it is hard to understand how such a modest change can cause such a gap in UV performance. The older lenses have older non-UV cured adhesives, so they work in better in UV photography. A newer lens, even if it were decoated, would not work unless you replaced the UV absorbing adhesives which would be a difficult project. this also explains my experience with some single coated lenses working fine for UV photography, while others did not - it wasn't the coating, but the adhesives in the lenses which was dictating which lens would work well in UV longwave photography

the simple answer is that there are lots and lots of older lenses out there that work just fine for UV photography; you don't need to mandate a nikkor but any nikon mount (Tmount etc.) or bellows lens will work. The older RF nikkors such as my 135mm f/4 nikkor lens head works fine on UV (see http://www.smu.edu/~rmonagha/bronadap.html for photo on Bronica S2A)

see http://www.smu.edu/~rmonagha/mf/uv.html on tips on using older glass lenses for longwave Ultraviolet photography with fuji tungsten film and modest cost UV-only pass filters (from edmund scientific etc.)

From Leica Mailing List:
Date: Sat, 25 Nov 2000
From: Kent Christensen lkchris@uswest.net
Subject: re: Filter Fray and Hoods

FWIW (quoted from "Leica R-Lenses" Edition Summer 1983 ...following explanation of what a UVa filter does) ...

In the past, this was done with a UVa filter also on Leica lenses. Leica lenses of the current generation (from about 1965 onwards) absorb ultraviolet rays through the use of certain types of glass and above all through a certain method of cementing the lenses, so that basically a separate UVa filter is unnecessary. Cementing with an Absorban layer carried out according to a Leitz patent guarantees identical color characteristics in all lenses and therefore a uniform, neutral color rendering. Even at very high altitudes. The UVa filter on Leica R lenses today therefore merely serves as a protection for the front element of the lens.

It must, however, be mentioned here that even high-quality filters may create problems in certain situations. At high contrast, for instance, during sunsets, in night shots including powerful light sources in the picture and when bright objects are photographed through a dark arch, the risk of reflections even from optically flat and coated filters is very great. Double images or a general degradation of the contrast or partial lightening through stray light are relatively frequent. In such photographic situations all filters, including the UVa filter, should be removed. With ultra-wide angle lenses, too, filters may lead to inferior photographic results. Owing to the wider angle of field the marginal light rays must traverse a slightly longer path through the filter in front of such lenses than the light rays in the center. This may often adversely affect the picture quality, and is one reason why, for instance, no filter is offered for the 19mm ELMARIT-R f/2.8 lens.

Skylight and haze filters

These slightly tinted UVa filters were in the past recommended for color photographs of subjects with exceptionally high UV and blue content of the light, such as subjects in the shade or distant views through slightly blue haze. Their use with the current Leica R lenses is discouraged, because they will make the color rendering unnaturally warm.

[Ed. note: a method to determine UV focusing offsets?...]
From Leica Mailing LIst:
Date: Sat, 6 Jan 2001
From: Christer Almqvist christer@almqvist.net
Subject: [Leica] Focus check (was Anybody use the 75 summilux on a .72x M6?

...

Thanks for the reply, Tom.

I just read an article about how to determine how to focus for IR film and I think I will use the method proposed there to check if my camera body and lens combo focuses correctly.

The method proposed (adapted to close range focusing) was:

- - set lens to shortest-but-one distance marked on the barrel
- - fix a piece of paper with a vertical line on a wall
- - place camera on tripod
- - adjust distance camera to wall so that vertical line is shown unbroken in finder
- - expose one frame
- - turn lens barrel (the one with distance scale) 2mm clockwise and expose
- - turn another 2mm and expose (repeat a few times)
- - go back to situation with unbroken line in finder and expose
- - repeat procedure above but turn barrel anti-clockwise

You may want to put the sticky portion of a post-it marker on the lens barrel with different coloured markings for the 2mm steps, and you may want to put post-it markers on the wall indicating how much you are off the distance marking which had been indicated to be correct. This helps greatly when reviewing the prints.

I will try this out with my skinny Tel-elmarit - a truly sharp lens, but not always with sharpness where I want it

Chris
- --
Christer Almqvist

[Ed. note: Mr. Brick is a noted AF digital camera engineer and author of many photobooks and photography articles...]
From Leica Mailing List:
Date: Fri, 16 Feb 2001
From: Jim Brick jim_brick@agilent.com
Subject: [Leica] Re: photography at altitude

There's more UV inhibitor in your lenses than there is in a UV filter. Unless your lenses are very old.

It becomes a sunny 22 rule.

Jim

Lee, Jonathan wrote:

>Guys,
>
>I'm off for some skiing at Banff (elevation 5000-8500ft).  Is there enough
>UV at these altitudes to make a UV filter more than just optional? In case
>the meter goes belly up, does the sunny f16 rule change appreciably at these
>altitudes?
>
>Thanks
>
>Jonathan Lee

From Rollei Mailing List:
Date: Wed, 21 Feb 2001
From: Marc James Small msmall@roanoke.infi.net
Subject: Re: [Rollei] ARGH! Sorensen and the Filter Myth!

John A. Lind wrote:

>I use a UV 0 on all lenses.  First, it cuts some of the distant haze
>outdoors.  Second, I found it warms the flash slightly indoors by cutting
>out some of the higher UV component.  There *are* some benefits visibly had
>by at least some of us using a UV 0 filter.

It matters not. Since the 1950's, the manufacturers have been arguing that you do NOT need a filter for routine photography, as the lenses have inbuilt UV coatings. Certainly, this is true for Nikon, Canon, Zeiss, Leitz/Leica, Rollei, and JSK. All are most adamant on this point.

Why pay top dollar for the finest lenses in the world and then degrade the performance through the use of an unnecessary filter? Degrade it it will, though often not by much.

Again, professionals -- who live by their gear -- virtually never use filters save for color correction.

Marc

msmall@roanoke.infi.net

From Rollei Mailing List;
Date: Wed, 21 Feb 2001
From: Bob Shell bob@bobshell.com Subject: Re: [Rollei] ARGH! Sorensen and the Filter Myth!

> From: Marc James Small msmall@roanoke.infi.net
> Date: Wed, 21 Feb 2001
> Subject: RE: [Rollei] ARGH!  Sorensen and the Filter Myth!
>
> By 1960, it was contended that
> the inner UVa filter was sufficient for all but photography at extremely
> high altitudes, say 20,000 ft/6,000m or above.

I've been told by optical designers that the cement used in modern lenses absorbs practically all of the UV, making UV filters unnecessary except in extreme situations.

Bob

From Leica Mailing List:
Date: Fri, 23 Feb 2001
From: Christer Almqvist christer@almqvist.net
Subject: [Leica] UV light 200yrs

The existance of UV light was proven 200 years ago to-day by a German by the name of Ritter. His other interests in life were occultism, women, alcohol and gaming. He died in 1805 at age 33.

With UV light becoming stronger each year due to the ozone layer getting thinner, it is surprising the filter manufacturers have not yet started using this as an argument for selling more filters. I have filters on all my lenses, not to protect the front element, no, I have them because of those UV rays.

Chris
- --
Christer Almqvist

From: dickburk@ix.netcom.com (Richard Knoppow)
Newsgroups: rec.photo.equipment.large-format
Date: Mon, 07 May 2001
Subject: Re: Source for UV Bulbs?

"Mark Westling" mwestling@home.com wrote:

>Can anyone point me towards a quality supplier of UV bulbs that would be
>appropriate for Platinum/Palladium printing?
>
>Thanks,
>
>Mark Westling
>mwestling@home.com
>

Try either Bulbman at: http://www.bulbman.com/ or Bulbs Direct at: http://www.bulbdirect.com/

You should join the Alternative Processes mailing list. For instructons see the FAQ at:

http://duke.usask.ca/~holtsg/photo/faq.html

There have been extensive discussion of light sources for Platinum and other similar processes on the list over the years. There is an archive at: http://members.xoom.com/altphotoprc/

However, it seems to be down just now. This is the correct URL. There is a web mirror of current postings at:

http://duke.usask.ca/~holtsg/photo/current

One possibility is to look for a used "plate burner". These are large UV lamps originally used for exposing the photo resist on printing plates. A great many of them have been junked due to the switching of this proccess to imagesetters.

---
Richard Knoppow
Los Angeles, Ca.
dickburk@ix.netcom.com

rec.photo.equipment.35mm
From: Graham Sheppard g_shepp@nnortelnetworks.com
Date: Tue May 15 2001
Subject: Re: Black light/UV photography

Someone posted this site in the rec.photo.nature group. It has an article on black light nudes . I haven't had a look yet ('onest guv!) but it may shed some, er, light on the subject!!

http://www.vividlight.com/articles/101.htm

Graham

Date: Sat, 19 Aug 2000
From: Robert Monaghan rmonagha@post.cis.smu.edu
To: NikonMF@egroups.com
Subject: re: uncoating and UV photography

the real problem is more likely to be the modern adhesives in current lenses are UV cured in many cases, and absorb UV much more so than the glass lens elements themselves. So the lens multicoating is more an indicator of the type of lens adhesives used, and their absorption of UV, than a real cause of the problem. After all, a single coating is 95% effective, and multicoating only raises that to 98% or so effective, so it is hard to understand how such a modest change can cause such a gap in UV performance. The older lenses have older non-UV cured adhesives, so they work in better in UV photography. A newer lens, even if it were decoated, would not work unless you replaced the UV absorbing adhesives which would be a difficult project. this also explains my experience with some single coated lenses working fine for UV photography, while others did not - it wasn't the coating, but the adhesives in the lenses which was dictating which lens would work well in UV longwave photography

the simple answer is that there are lots and lots of older lenses out there that work just fine for UV photography; you don't need to mandate a nikkor but any nikon mount (Tmount etc.) or bellows lens will work. The older RF nikkors such as my 135mm f/4 nikkor lens head works fine on UV (see http://www.smu.edu/~rmonagha/bronadap.html for photo on Bronica S2A)

see http://www.smu.edu/~rmonagha/mf/uv.html on tips on using older glass lenses for longwave Ultraviolet photography with fuji tungsten film and modest cost UV-only pass filters (from edmund scientific etc.)

From Hasselblad Mailing List;
Date: 10 Aug 2000
From: Patrick Bartek bartek@pdai.com
Subject: Re: 105 UV Sonar

Austin Franklin wrote:

> > This was a very special lens, custom made to high tolerances.  $4000
> > is a ridiculous price for it, even a used one.  You pay that much for
> > a new plain old 40mm.
>
> Since when is a 40mm 'plain old'?  Why do you say it's 'high tolerance'?   I
> don't find 'high tolerance' listed in the description in the Hasselblad
> Compendium, perhaps you have other literature that says that?  It does  say
> it has 'quartz and fluorite elements'.

Since when the 40 is a massed produced in large numbers lens, readily available for purchase at any high end camera store. You just walk in and point, "I'll take that one." It is common place, but expensive, like a Mecedes Benz. The 105 UV Sonnar, on the other hand, is a special use, special order only, very expensive item: It's not made until you place the order and plunk down 15 grand (US dollars). It is more akin to the racing cars that Mecedes makes -- very few, very special, VERY expensive. They are designed for one specific purpose -- racing -- and are not really of any use to the general automobile user like the 105 UV is not to the average photographer.

The reason for "high tolerance" is because of the special use of the lens, mostly scientific and forensic, where exactness is paramount, and the special refractive elements, quartz and flourite, which are more delicate and thus more easily damaged during grinding and polishing than harder, regular optical glass.

The lens is designed mainly to focus ultraviolet light (as well as the visible wavelengths, too). Conventional optical glasses like are used in the other Hasselblad lenses (as well as other manufacturer's optics) is unsuitable, because regular glass ABSORBS most of the UV light making it unsuitable for use in a lens that is suppose to TRANSMIT UV wavelengths. Also, regular lenses aren't designed to bring UV into focus in the film plane, which is okay since most of it is filtered out before even reaching the film, either by the lens itself or by that ubiquitous UV filter everyone is told to use.

Thus the requirements of this lens DEMAND the highest exactness and tightest or highest tolerances that can be delivered.

> Just FYI, I have no interest in the lense, but it raises the hair on the
> back of my neck someone claims something is worth 'so much', but fail to
> mention what would be entailed in someone getting 'that much' for it.   If
> it was based on sales you have seen, then I'd give it some  credence...but
> it isn't.  It's just pure speculation.  I'm not saying it might not be
> worth that money under the right circumstances, but realistically, it's  a
> tough to sell item.  As I've said, it's only worth what someone is  willing
> to pay for it, and not a penny more.

In one way, you are correct: the worth of something is what most people are willing to pay for it; but this general formula applies to things that are not rare. Those things that are "rare" or "special" add another variable to the "worth" equation, which in most cases increases the "worth" of the item. There is also "demand," and who needs the item and for what.

Most average consumers are not purchasers of rare or special use items like our coveted 105 UV Sonnar. So, here the general rule breaks down. A tool that is rare, that can do a special, specific task, even though that task is not in wide demand; but there is a demand, though small, makes that tool valuable. It has to be bought regardless of the price to satisfy that small, necessary need.

I've done a little checking. The new price today for the 105 UV Sonnar is $15,000 US. The lens has such little traffic on the used market that it is not even listed in the Blue Book of used photo equipment. But a fair market price today, even for a minty, older lens of this type, would be around $7000 to $8000 US (about half the new price) according to those who deal in used equipment daily, I talked to.

I would not sell this lens for the offered price of $4000. I'd rather use it as a paper weight instead, than essentially give it away to a predatory, low-baller, who will turn around and try to sell it for $10,000, but will settle for 6000. Of course, I wouldn't be marketing this lens to the general photographer. You don't try to sell air conditioners to Eskimoes. I would contact scientific research companies, universities, museums, geodetic mapping companies, etc., who might have a need for it and have the budgets for such items.

--
Patrick Bartek
NoLife Polymath Group
bartek@pdai.com

From: j.e.mcmillan@nospam.sheffield.ac.uk (John McMillan)
Date: Mon, 16 Jul 2001
Newsgroups: sci.optics
Subject: Re: UV-light source

markus_eklund@yahoo.se (Rejn) wrote:

> Hi
>
> I'm searching for a small UV-light source. Prefferrably a LED since
> size is of outmost importance, as well as prize. (approx 15000
> pcs/year)
>
> I have heard that there is something available around 393nm, but I do
> not know where to find it.

Nichia make them with 370nm peak, Don Klipstein has a page of information.

http://www.misty.com/people/don/ledbl.html

Here in Britain I can buy them in small quantities from Farnell Components as 335-1312 and 335-1324 for o20 each

Date: Sat, 05 May 2001
From: "Jeannie" see.message.body.for.e-mail@address.com
Newsgroups: rec.photo.equipment.35mm,rec.photo.film+labs
Subject: Is fast-action UV photography possible? (x-post)

Wildly cross-posted.

I was interested in a hands-off approach to figuring out whether a particular bird species (Steller's jay) has UV pigments in its feathers. I'm limiting myself to photography in the field with a telephoto lens. I don't want to deal with the heavy logistical baggage (permits, equipment, etc.) of a hands-on or lab-oriented approach.

So far, what I've learned is that most modern lenses are multi-coated and will not transmit UV waves very well. A UV-specialized quartz lens is probably ideal, but very expensive. Alternatively, I need an older uncoated or single-coated lens with not too many elements. Does such a (telephoto) beast exist for Canon FD or EOS mount? I'd have to limit myself to something that can be rented or bought inexpensively second-hand.

I read that using a mirror telescope lens was one way to photograph UV reflected light. Would a mirror camera lens be equivalent?

There seems to be a need to stop down the lens, to cut down on light aberrations and also to help focus. The point of focus is farther than with normal visible light, so more DOF helps ensure proper focus. That would require longer shutter speeds, but I don't think I have the luxury of that with wild birds. In addition, the filter for UV photography has a very high filter factor, from 8-20 for the B+W 403. So, I would need high speed film. Fuji RTP 64 was suggested on quite a few web sites as a good UV film, but is not practical for action. I've also read that TMAX 400 or just about any B&W; panchromatic film would be a good choice. I was wondering about the push possibilities. Would I be able to shoot at high speeds, push process, and get any results?

Another possibility is to use electronic flash to get some more light onto the subject. Electronic flash contains UV wavelengths, but some flash modules usually have a UV-absorbing filter on it. How would I go about figuring out whether a particular flash has such a filter?

Fast-action UV photography? Am I dreaming?

Thanks for your input,

--
Jeannie
E-mail: moonflour at bigfoot dot see oh em
Web: http://www.talisweb.com/jeannie/

Date: Sat, 05 May 2001
From: Bill Tuthill ca_creekin@yahoo.com
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Is fast-action UV photography possible? (x-post)

> I was interested in a hands-off approach to figuring out whether a
> particular bird species (Steller's jay) has UV pigments in its feathers.
> I'm limiting myself to photography in the field with a telephoto lens...

What an interesting question, Jeannie!

I believe you need an old, uncoated telephoto lens. It will probably have to be manual focus.

Bjorn Rorslett, in addition to having written great critical appraisals of Nikon lenses, has an excellent website section on UV photography:

http://www.foto.no/nikon/uvstart.html

From: "Mxsmanic" mxsmanic@hotmail.com>
Newsgroups: rec.photo.equipment.35mm
Subject: Re: diffraction limited optics was Re: Why is Leica so expensive?
Date: Mon, 08 Oct 2001 

"ArtKramr" artkramr@aol.com> wrote...

> BTW, if we used a quartz element in a 50mm
> Summicron the lens would weigh more that the
> M Leica body and the lens would probably cost
> about $5,000 (g)

Quartz is only slightly more dense than most other optical glasses;
fused silica or amorphous silicon dioxide (same ingredients as quartz,
without the crystal structure) has a density of 2.2 g/cc, very much in
line with other glasses.

The lead glasses are the heaviest, with densities as much as twice as
high as most other glasses.



From: brianc1959@aol.com (brian)
Newsgroups: rec.photo.equipment.35mm
Subject: Re: diffraction limited optics was Re: Why is Leica so expensive?
Date: 8 Oct 2001 

Crystal quartz is birefringent, and thus not suitable for use in
ordinary optical elements.  It is used quite often in anti-aliasing
filters for digital cameras.  Fused silica, as you point out, has a
very low density.  It also has a low index of refraction and fairly
ordinary dispersion behavior.  The only advantage of fused silica is
that its transmission extends far into the ultraviolet and infrared,
and it is often used as a flint element in combination with calcium
fluoride to make wide-spectral range achromatic systems.  There is
little or no advantage in using fused silica elements in normal
photographic lenses.

Brian


"Mxsmanic" mxsmanic@hotmail.com> wrote 
> "ArtKramr" artkramr@aol.com> wrote 
> 
> > BTW, if we used a quartz element in a 50mm
> > Summicron the lens would weigh more that the
> > M Leica body and the lens would probably cost
> > about $5,000 (g)
> 
> Quartz is only slightly more dense than most other optical glasses;
> fused silica or amorphous silicon dioxide (same ingredients as quartz,
> without the crystal structure) has a density of 2.2 g/cc, very much in
> line with other glasses.
> 
> The lead glasses are the heaviest, with densities as much as twice as
> high as most other glasses.



From: baalke@zagami.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Bee Vision: The Latest Buzz in Space Exploration
Date: 15 Oct 2001 

http://www.jpl.nasa.gov/technology/features/uv_bees.html

Bee Vision: The Latest Buzz in Space Exploration
Jet Propulsion Laboratory
October 15, 2001

With so many flowers and so little time, life as a bee is not always as
sweet as honey.

Fortunately, many flowers help these hard-working insects by showing them
patterns that direct them to food sources. These patterns, however, are only
visible in the ultraviolet range, something that many insects can detect.
Humans, on the other hand, cannot see these signatures with the naked eye,
but instead must use special equipment.

To the delight of scientists, technological progress at JPL has produced a
high-performance chip that is capable of detecting very weak ultraviolet
signals. The new chip has increased sensitivity and robustness to the point
that it could be used to explore distant planets.

Yet searching for life on distant planets was not the original goal of the
scientists who developed this new technology. A simple demonstration of a
camera containing the new chip showed that the technology intended for
ultraviolet astronomy could also detect ultraviolet signatures of Black-eyed
Susan flowers, and gave researchers a glimpse of its potential for future
applications in astrobiology.

"We had this sophisticated ultraviolet chip technology that we had used, for
example, to image galaxies, and we wanted to set up a simple, indoor
demonstration. This simple demonstration of a new technology may lead to
exciting new applications in the search for life in the universe," said Dr.
Shouleh Nikzad, researcher and head of the Nanoscience and Advanced Detector
Arrays Group at JPL. "What may appear as a lifeless environment in visible
light could come alive when seen in ultraviolet. This is an example of the
vital part that technology plays in all sciences."

Using ultraviolet signatures to study the chemical composition and processes
in celestial objects is nothing new. Ever since humans figured out a way to
send spacecraft beyond Earth's atmosphere, ultraviolet astronomy has given
scientists a new view.

But the key to flying this technology on a future spacecraft, in addition to
its high performance, is its exceptional durability. The reason for its
superior capacity to withstand the rigors of space flight is built into the
tough silicon lattice of the chip. The camera uses the same charge-coupled
device, or CCD chip, found in a regular camcorder, only modified to be
sensitive to ultraviolet light. The chip response to light changes
dramatically when a few layers of crystal silicon are added to the chip
surface with a procedure called delta doping. The key to seeing the
ultraviolet light is to control what happens to the electrons that are very
near the surface of the chip. By building this control into the silicon
crystal, JPL scientists created an extremely durable device.

"The camera is sturdy, just like a camcorder, and the chip technology is
very durable. I keep the chip in my desk drawer; take it on the field, store
it in the lab. It's extremely robust," Nikzad says as she handles the
lightweight camera.

Stability is what some other devices that see in the ultraviolet lack. Those
devices must work under tightly controlled conditions such as low
temperatures, or must be in a vacuum, or they lose their sensitivity to
ultraviolet photons almost immediately.

The chip's ability to see in ultraviolet is stunning. Compared to a similar
imaging array on the Hubble Space Telescope, this chip is three to 10 times
more efficient in detecting ultraviolet light, depending on the region of
the spectrum.

Eventually, astronomers might make a beeline for this technology to help
them study the cosmos.


From: brianc1959@aol.com (brian)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: flare and MC Re: Schneider Super Ang question
Date: 30 Oct 2001 

Robert:

I'm curious about the UV lens you are thinking about.  If its
something simple like a landscape lens then you probably wouldn't have
to worry about coatings.  A symmetrical hypergon-type design would
also work very well - you could stop it way down and still get
relatively little diffraction blurring due to the short wavelength.

Brian


rmonagha@smu.edu (Robert Monaghan) wrote 
> Hi Brian!
> 
> thanks for your most interesting and informative note; it is nice to learn 
> more about some of these issues, and I was esp. interested in the coatings 
> fab and cost issues, as I have to pay for all this stuff ;-) ;-) 
> 
> I have assumed that there must be some benefit to the coatings with quartz 
> elements, as I have seen these sold, at a premium, from Edsci (Edmund 
> Scientific's Optical catalog group) with a BBAR coating, IIRC, on the UV 
> quartz glass elements. I was a bit surprised to see such a wide range 
> short UV to IR coating offering, and debated buying the more costly coated 
> elements over the still pretty pricey individual elements for a homebrew 
> quartz shortwave UV lens design, hence my interest ;-)
> 
> I am also keeping my eyes out for some ultra cheapy badly coated zooms 
> such as the green biased zooms I have heard about, as an example of an 
> unusual lens flaw for my lens faults pages and collection ;-) I have seen 
> stats that even small errors, in the 5% to 10% range, can be cause for 
> rejection of some coatings as too thin/thick, and so adds to costs and 
> rejection rates of these elements, and so may justify the higher costs of
> the multicoated elements. I'm still not sure why they don't just strip off 
> the coatings chemically and start again? ;-) Maybe they do? But I suspect 
> that a large part of the extra cost of multicoating is simply that we as 
> users have been led to believe that only a multicoated lens is adequate, 
> and a single coated lens is not as usable, when in most cases the real 
> divide is between uncoated and coated lenses...
> 
> regards bobm


From: brianc1959@aol.com (brian)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: flare and MC Re: Schneider Super Ang question
Date: 31 Oct 2001 

Robert:

I did some quick design work and found that a two element quartz
system in the Hypergon configuration (all radii identical, optical
power introduced by lens thickness and element separation) would be
ideal for 4x5 or 8x10 in the violet-to-deep ultraviolet range. 
Extremely flat anastigmatic field and no coatings necessary.  At f/32
to f/64 the images will be as sharp as a plasmat one or two stops
faster in visible light.  If you're willing to put up with more
aberration (mainly lateral color and astigmatism) you could go with a
single element landscape lens.  Good fused silica is not necessarily
too expensive if you can find a surplus source.  Even a fused quartz
telescope blank might serve your purposes well.

Brian


rmonagha@smu.edu (Robert Monaghan) wrote 
> yes, I was interested in trying out UV photography, and found it
> delightful that some of the older lenses could be pushed into the longwave
> UV range (see notes at http://medfmt.8k.com/mf/uv.html), but the
> cost of shortwave UV quartz optics generally started in the multikilobuck
> range for 35mm and over $10k for the zeiss UV lenses for hasselblad on
> 6x6cm etc.  So I maintain an interest in other options, including possibly
> some simple lens designs replacing existing elements in a mounting with
> quartz elements in a modest simple design lens. But the coatings were 
> interesting since I would find it hard to evaluate flare assuming I was 
> shooting thru a UV only pass filter (quite dark), given the flare might be 
> in UV rather than visible light ranges ;-) grins bobm


From: "LOWDER, KEVIN G" LOWDERKG@tdprs.state.tx.us>
To: "'rmonagha@mail.smu.edu'" rmonagha@mail.smu.edu>
Subject: old takumar quartz
Date: Fri, 2 Nov 2001 

Sir, 

Given your experience, I thought you or someone you know may have some
insights on a lens.  It's a quartz takumar, 85mm, f3.5 with a preset
diaphragm that has a bellows II Unit (M42 mount).  It has two focusing
rings, two filters (one marked 365 mu and another marked 267 mu) and a
correction scale on lens.  Even more odd, it has a two aperture rings. I
acquired it earlier this week.

I've searched the net extensively, spoke with Pentax and posted a few
inquiries on some of the boards.  But I can't find a soul who knows how it
operates or what it may be worth. Too bad there were no instructions.  It
was made in 66 and contains quartz and glass.  Also learned that Asahi
-Pentax came out with an "ultra-achromatic 85mm f4.5", automatic diaphragm,
between 72-75.  This later version was quartz and fluorite and retailed
around $1400.00.   I've been looking for the automatic version (f4.5) for
years to get better UV photographs of injuries and old bruises.  Perhaps the
3.5 will do until an "ultra-achromatic" comes along.  Just in the dark on
how this 3.5 operates.    

Any assistance in this endeavor is dearly appreciated.     

Kevin

[Ed. Note: If anyone can assist Kevin, please contact him! Thanks!]


From: Paul Rubin phr-n2001d@nightsong.com>
Newsgroups: rec.photo.equipment.35mm
Subject: Re: OT: lenses from diamonds?
Date: 17 Nov 2001 

Bruce Murphy pack-news@rattus.net> writes:
> > Assume that it's financially feasible to make one, what would the optical
> > quality of a diamond lens be like? Would it be the ultimate lens?
> 
> And precisely how were you going to grind diamond lens elements?
> Assuming it was financially feasible, what would the optical quality
> of the plastic lid from a Pringles tin be like. Would it be
> the ultimate lens?
> 
> Makes about as much sense.

The Mariner IV spacecraft used a flat diamond window for one of its
ultraviolet cameras if I remember correctly.  Ordinary glass didn't
transmit UV, and quartz couldn't stand the temperature of orbiting
Venus.  The diamond window was something like 3/4" in diameter and the
diamond for it cost something like $750,000.  It made the news that
the spacecraft integrator had gotten an exemption from paying import
duties when it bought the diamond, on the grounds that it was purchased
for re-export to Venus.


From: "Tommy Huynh" tommyphuynh.nospam@yahoo.com>
Newsgroups: rec.photo.equipment.35mm
Subject: Re: lenses from diamonds?
Date: Sun, 18 Nov 2001 

The things that make diamonds an ideal gem make it a bad choice for lens
elements.  Diamonds have a very high refractive index, which gives it it's
sparkle, but like many materials with high refractive indexes, it also has
very high dispersion.  Dispersion is how much the refractive index changes
relative to wavelength and is the cause for the "prism effect" or "fire" as
jewelers call it.  To us camera folks, that means chromatic aberration, and
using glass with low dispersion to mitigate this effect is the idea behind
Canon using fluorite elements and Nikon using ED (extra low dispersion)
glass.

So if it were possible, it wouldn't make for great lenses (for the visible
spectrum anyways) but it would make for just about a great everything else.
In addition to being the hardest known material, diamond has the highest
thermal conductivity and can be made to have coefficients of friction lower
than even Teflon.  If you could imagine an engine made of diamond, it would
be able to run harder,  never wear (just about), wouldn't need any coolant,
or oil.  Sounds far fetched but I'm thinking they might be able to someday
mold "large" diamond like materials by bonding carbon fullerenes, or maybe
by some process nobody has though of.

From: "BABOLAT C." CLAUDE_BABOLAT@SODERN.fr>
To: "'rmonagha@post.smu.edu'" rmonagha@post.smu.edu>
Subject: UV lens
Date: Fri, 17 Aug 2001 

informations on UV lenses manufactured by SODERN
 UV lens by SODERN.doc

regards

Claude BABOLAT    EADS  SODERN 

[Ed. Note: please contact Claude Babolat at Sodern for latest info on their UV optics!]


Date:   Wed, 16 Jan 2002 
To:     rmonagha@mail.smu.edu
From:   Eija Isaksson eija.isaksson@iki.fi>
Subject: Missing uv-link

Dear Robert,

I read an interesting article in our Finnish science magazine "Tiede" 
("Science" in English) about flowers, birds and insects. I found an 
explanation, why there are so few red-coloured flowers here in far North - 
simply depending on the reality, that our insects do not see the red colour 
- and main pollinators here are the insects.

But, our insects see the uv-light! The Tiede magazine gave me this link: 
http://www.smu.edu/~rmonagha/mf/uv.html
I confess, the magazine is pretty old, from May 2001, but, now I want to 
write a little more about uv-light, and that's why I'm asking you, does the 
link above exist somewhere today?????? Hopefully!!!! If yes, please give me 
the current link!!! Many thanks!!!!

Regards from "far North",

- Eija



From: eric boxall ericb@abc_fenris99.demon.co.uk>
Newsgroups: rec.photo.misc
Subject: ULTRAVIOLET FILM FOR PENTAX 67 II ?
Date: Tue, 11 Dec 2001 

rgs50 rgs50@bellsouth.net> writes
>Would someone please tell me where I can get ultraviolet film in 120 mm &
>220 MM format for a Pentax 67 II ?  From my VERY limited readings references
>are made to ultraviolet film and I have ultraviolet filters on my lenses but
>I want to experiment with the film too if it's available.  Thanks.
>

Hi Robert,

Are you using true UV filters ... very dark blue or visually opaque ...
or just the standard UV filters sold for normal photography ? These
latter filters adsorb UV, not pass it.

If you are using true UV filters, I can see some potential difficulties
with focussing. I would expect the lens to focus UV to a different plane
than ordinary visible light. This certainly happens with IR and the
shorter wavelengths will be bent far more strongly than are the longer
ones.


Unless things have changed dramatically, all film is sensitive to UV.

Many years ago, working on a scientific project, I set up a piece of
equipment to image in the UV region. We wanted to take photos. We could
not see an image visually and we had no light meter on the camera. We
used Pan F (50 ASA) and estimated the exposure as probably being similar
to ordinary work, so we set an exposure of 1 sec. Our negs were totally
fogged ! We had to cut the time to 1/250th.

Now, this light was "Hard" UV ... way down at 285 nm and we had an all-
quartz optical system. Glass wont transmit such short wavelengths but it
does transmit down to about 350 nm and it is this radiation which
produces the very saturated blue skies seen on transparencies shot at
high altitude and on clear days.

I'd be inclined to just load some ordinary slow to medium film, fit the
UV filter and shoot. A cheap experiment !

If this doesn't produce the results you require then I would look at the
Web sites for the film makers (Kodak, Ilford, etc.) to see if they have
any data sheets. Kodak particularly has a wealth of information,
although I do not know whether there is anything to do with UV imaging,
as I haven't looked for this.

Let us know how you get on.

Regards, 
-- 
Eric
Email to:beric@fenris99(dot)demon(dot)co(dot)uk 


From Hasselblad Mailing List:
Date: Sun, 03 Mar 2002 
From: Rolland Elliott rolland_elliott@hotmail.com
Subject: [HUG] 62mm f/2 UV Planar Lens with M67 mount made by Carl Zeiss

Anyone know anything about the lens below? Can it be mounted on a Hassy?
What exactly is a M67 mount?  Is it made of quartz instead of glass for UV
photography?  I have the opportunity to buy one and want more info on it.

62mm f/2 UV Planar Lens with M67 mount made by Carl Zeiss
Thanks, Rolland




From: "Legal Tender" ariz@galaxynet.com
Newsgroups: rec.photo.equipment.35mm
Subject: U-360
Date: Tue, 26 Mar 2002 


Hi

Does anyone know where I could get a Hoya U-360 filter. Hoya has
discontinued them and of course I decided to drop mine.

Thanks
Frank


Date: Thu, 28 Mar 2002
From: "David Gilblom" daveg@pacificphotonics.com
Newsgroups: sci.optics
Subject: Re: UV to vis conversion


Bolek,

Yellow highlighter is almost exactly the same as the original UV-to-visible
conversion dye sold under the name "Lumogen" used to improve UV sensitivity
of CCDs.

Dave

--
David Gilblom
Pacific Photonics, Inc
daveg@pacificphotonics.com
www.pacificphotonics.com


From: Bjorn Rorslett nikon@foto.no
rec.photo.equipment.35mm,rec.photo.film+labs,rec.photo.technique.misc
Subject: Re: Is fast-action UV photography possible?  (x-post)
Date: Thu, 10 May 2001


Jeannie wrote:
>
> Wildly cross-posted.
>
> I was interested in a hands-off approach to figuring out whether a
> particular bird species (Steller's jay) has UV pigments in its feathers.
> I'm limiting myself to photography in the field with a telephoto lens.  I
> don't want to deal with the heavy logistical baggage (permits, equipment,
> etc.) of a hands-on or lab-oriented approach.
>
> So far, what I've learned is that most modern lenses are multi-coated and
> will not transmit UV waves very well.  A UV-specialized quartz lens is
> probably ideal, but very expensive.  Alternatively, I need an older uncoated
> or single-coated lens with not too many elements.  Does such a (telephoto)
> beast exist for Canon FD or EOS mount?  I'd have to limit myself to
> something that can be rented or bought inexpensively second-hand.
>
> I read that using a mirror telescope lens was one way to photograph UV
> reflected light.  Would a mirror camera lens be equivalent?
>
> There seems to be a need to stop down the lens, to cut down on light
> aberrations and also to help focus.  The point of focus is farther than with
> normal visible light, so more DOF helps ensure proper focus.  That would
> require longer shutter speeds, but I don't think I have the luxury of that
> with wild birds.  In addition, the filter for UV photography has a very high
> filter factor, from 8-20 for the B+W 403.  So, I would need high speed film.
> Fuji RTP 64 was suggested on quite a few web sites as a good UV film, but is
> not practical for action.  I've also read that TMAX 400 or just about any
> B&W; panchromatic film would be a good choice.  I was wondering about the
> push possibilities.  Would I be able to shoot at high speeds, push process,
> and get any results?
>
> Another possibility is to use electronic flash to get some more light onto
> the subject.  Electronic flash contains UV wavelengths, but some flash
> modules usually have a UV-absorbing filter on it.  How would I go about
> figuring out whether a particular flash has such a filter?
>
> Fast-action UV photography?  Am I dreaming?
> Thanks for your input,
> --
> Jeannie
> E-mail: moonflour at bigfoot dot see oh em
> Web: http://www.talisweb.com/jeannie/

A nice dream that never may become true. The only candidate for
long-lens work would be a mirror lens (preferably, a really old one).
However, to shoot in UV, you'll need a UV bandpass filter (passing UV
but nothing else) and this filter is literally black (visually opaque).
How are you going to focus your long lens if the bird isn't stationary,
if all you see in the finder is total blackness?

In the case of IR photography, it's technically feasible to mount the
necessary IR filter behind the camera reflex mirror, in front of the
film. However, this might be difficult for UV shooting simply because
this needs very thick glass-mounted filters (Wratten 18A or
equivalents), so fitting the filter into space and still keeping true
focus of the camera is not physically possible. You could always have a
camera (permantently) modified with such a thick filter in front of the
film, but then the camera's focusing needs to be modified as well.
Sounds expensive to me, and you would run into problems with keeping the
filter free from dust and scratches.

Anyway, using a medium-speed b/w film such as Tmax400 would be preferred
to colour films which have slow UV "speeds".

Regards
Bjorn Rorslett
Visit http://foto.no/nikon/ for UV & IR Colour Photography and other
Adventures in Nature and Digital Photography


Date: Sun, 25 Mar 2001 
From: Andreas Reichelt a0000613@unet.univie.ac.at
To: rmonagha@post.cis.smu.edu, nikon@foto.no
Newsgroups: rec.photo.equipment.misc
Subject: uv photography

Hello!

I am a student who is interested in uv-photography (adopting a
bee eyes' point of view ;-).

I greatly appreciate the webpages dealing with how to do that when
one is on a budget. I have one suggestion and several questions.

If multi-coated lenses are a problem, can this be helped? Dr Roman
Ginner from the biology department Vienna has suggested to use
a Metal-polish like "Unipol" (one can get that at a Goldsmith's) to
get rid of the coating. That would involve getting the lenses out
and back again, though. I'd very much like to know whether you
think that's practical.

My set-up is a Canon EOS 1000 with a 50mm Lens design with a
Cokin system P mounted on a 52mm ring. Unfortunately, the people
at my local store told me that the Kodak Wratten #18a filter
isn't available only after the rest of my setup was in place.

So my question is what type of filter you'd recommend, where to
order it (and have it shipped to Vienna)? The info on several
websites does mention a few things, for instance a U-360 at
Edmund scientific for 65$. Problem is, the specs are 53x53x3mm
for the square, and I can't make much of that (neither can
some friends of mine who have more experience, since the filters
are so rare and the American system seems to differ from the European).

So I am reluctant to buy something without knowing how good it
matches to my setup (if all else fails I guess I'll have to glue
it to the Cokin holder or somesuch, but still).

Suggestions and recommendations are very much appreciated.
Thanks!

Regards
Andreas

[Ed. responds:

The EDSCI filters are square shaped, designed for square holders, rather than the
usual round shape found with many camera lens thread filter mounts. There
are lots of older Gelatin filter holders (also square) and Cokin (A for amateur,
P for professional or larger size lenses) that can be adapted easily to 
mount such square filters (mount in cardboard). 

Don't polish the lenses. I believe the problem is not the coatings, but rather
the modern adhesives used in newer lenses which is the problem. These glues are
used to bond the lens elements together into groups, as one example. Such glues
strongly absorb UV light, and are even "cured" by using a UV light source. If
these glues are used in the lens, as on many modern lenses, then polishing out
the coatings won't alter their absorption of UV light. You should remove any
haze or UV filters, of course, as these do reduce the amount of UV getting to the lens.

So the trick in longwave UV photography is to find lenses which don't use
such modern adhesives. This problem leaves out most of the modern (AF/MF) lenses, except
perhaps a few simpler designs which don't use glued together elements in groups.
But lots of older lenses which can be converted to modern camera mounts are out
there which don't have these modern adhesives. So they will pass some amount of
longwave UV (the glass doesn't cutoff until past 320 nm depending on formulas).
So you simply have to test by photographing with a UV only filter (U-360, Kodak#18a..)
to see if UV is being passed by the older lens, or if it is being absorbed.

The older the lens, the more likely it won't have modern adhesives or glasses which
absorb UV. The simpler the lens, the more likely that less UV will be absorbed. In
other words, designs (such as wide angles, some telephotos) which have thick and heavy
chunks of glass are more likely to absorb a lot of UV than lenses which have only a
few (3 or 4) elements which are thin sections of glass.

A second point is that older cameras work just as well, or better, than the modern
cameras for longwave UV work. You don't need the latest matrix metering or AF body.
A low cost older body (Nikon F, Minolta SR(t), Pentax M42 mount) is a better match. 
You will find lots of candidates (including some T-mount lenses) to test for UV use.
As a bonus, these older fixed focal length (prime) lenses will often be shockingly
cheap, as well as usable for general photography (oftentimes with fine bokeh).
Because of long exposure times with some dense UV pass filters, you will benefit from
a "B" (for bulb) or "T" (for time) exposure option, which most mechanical cameras offer.

A lot of the simple lenses from the 1950s will work for longwave UV work, many of those made in
the 1960s. Some of the lenses from the 1970s are candidates for longwave UV work too.  So
forget about lenses from the 1980s and 1990s, and look for those golden oldies!]



From hasselblad mailing list:
Date: Sun, 9 Jun 2002 
From: Ken Martin kmartin@ventur.net
Subject: RE: [HUG] Curious about a Hassy lens on eBay.... 105 UV-Sonnar..?

David:

   Went to my copy of the Hasselblad System Compendium by Richard Nordin
and found the following.  The lens was made from 1968-1982 in the "C"
version and from 1982 to the current time in CF version.  It is listed
as a special purpose lens with quartz and fluorite elements so that the
UV light is transmitted to the film.  It is a special order item and was
designed for scientific applications and initially for the space
program.  According to my book, there were less than 100 produced in the
last 15 years.

Ken

-----Original Message-----
From: David Meiland [mailto:david@meiland.com]
Sent: Sunday, June 09, 2002 
To: hasselblad@kelvin.net
Subject: [HUG] Curious about a Hassy lens on eBay.... 105 UV-Sonnar..?

I was just cruising eBay and came across a Hasselblad/Zeiss 105/4.3
UV-Sonnar, something I've never heard of:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item;=1357023494

The listing indicates that this might be for authenticating maker's marks
on artwork or something like that. Can anyone give me the lowdown on this lens?

Thanks,

David Meiland
http://davidmeiland.com


from hasselblad mailing list:
Date: Sun, 9 Jun 2002 
From: Frank Filippone red735i@earthlink.net
Subject: RE: [HUG] Curious about a Hassy lens on eBay.... 105 UV-Sonnar..?

The last one showed up in Prague or somewhere like that, and it was unsold
at $3500.  It is a psecial lens designed for NASA to look for UV radiation
from crops, etc.....  It has other uses, and is uncoated.    It probably
served to "read" the light reflected from paintings, as this is one of the
ways they authenticate the canvas......  they can look "under" the fist
layer of paint......

By far, the most exotic lens in the Hassy stable.....


Frank Filippone
red735i@earthlink.net


From: w-buechsenschuetz@web.de (Winfried Buechsenschuetz)
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Cheap, used 90mm M-mount?
Date: 23 Jul 2002



T. P. t.p@nomailthanks.com wrote...
> The balsam is made from some rendered down animal product that is
> probably too gross to be mentioned here (!).

Older lenses were cemented with canadian balm, a stuff produced by
canadian pines. It has a refraction index very similar to that of
common optical glass. It was also used in microscopy for embedding
objects.

Newer lenses (from the mid-60s and later) are cemented with a
synthetic glue which is hardened with UV radiation. It is anorganic
and therefore much less affected by fungus than the organic canadian
balm.

Winfried


[Ed. note: UV is often used for alternative photo processes such as cyanotype]
from camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
Subject: Re: [Cameramakers] Surplus Military lenses??
Date: Fri, 9 Aug 2002

Mac wrote:
How can I figure out the focus (bellow ext) needed to project the 120 neg
to 48" with this lens? What is the math involved?
..........Does this sound like it will work? project a 120 neg to 48" wide.
Mac

Hi there,

     I have built optical instruments before and have made the huge mistake
of using a lens on the project just because you found it cheap.....

      I do not know if this lens will work on your project...... I would say
that the odds are that it will not.... Most glass lenses, and I believe
plastic as well,  act as  tremendous Ultra Violet filters.. and they will
block the  necessary UV range that you need for exposure....

      I am in the process of building a UV enlarger my self...What I found
in my research is that El Nikor enlarging Lenses are made of a special
optical glass that will pass the needed UV range up to 425 nm....... Most
other lenses and  I believe plastic will stop the UV transmission dead in
its tracks at about 200.  On the Alt Photo list  we had discussed this  and
a man took a El Nikor lens and tested it on a UV spectrometer and it
verified what I am saying...

      If you are covering  6x6 format you will need a 80mm to 90mm lens and
6x7 format you will need  105 mm..   The shorter you can keep the focal
length  to your format the larger you can enlarge in a given distance.... I
believe they make a special wide angle lens that will  some what shorten the
distance needed to project your image  to a  final 48 inches diagonal  but
they are very  expensive lenses and I seldom have seen them  for sale
used... Most All El-Nikor  enlarging lenses are a high quality 6 element
lens and are usually f5.6 in the sizes we are talking about... They are
usually under $50 on E-bay ...

      Also to enlarge to that huge size will require a very long exposure
and you may find that the film can not handle the infrared heat as light
fall off increases dramatically the larger you go......... On my project I
am trying to find out how to increase the speed of dichromate sensitized
paper to reduce the time I need to expose... If you come across any
information on this  I hope that you would pass that along to me...

      I imagine you can just set up a standard  medium format enlarger
rigged with " first surface" mirrors to channel the  sun light into the film
chamber into a dark room or box  if you are setting up a daylab deal you
would have to block all light fom the film plane down to the paper plane
......I would not use the condensers as they too will block the UV as well
as standard mirror....

      Now you know everything that I know.. Good luck... Send me a picture
of the thing when it is built....

Regards,
John Cremati


from camera makers mailing list:
Date: Fri, 09 Aug 2002 
From: Robert Mueller r.mueller@fz-juelich.de
Subject: Re: [Cameramakers] Surplus Military lenses??

Please see below!

 you wrote:
>Hi john!
>
>Very helpful. I don't have a problem getting a Nikor lens. i was under
>the impression one of these large lenses would put out a lot more light
>(f 1). I did realize the plastic elements would probably block the UV.

Plastics can transmit UV very well; however, much
plastic contains a UV blocking dye.  You can only learn that by asking the
maker or testing it somehow.  There is no need for the dye in lenses so it
may not be included.

>Yes, I do expect a very long exposure.I'm guessing a 20 min Cyanotype
>contact print would take a couple hours with the solar enlarger.
>
>Well, i might have to rig the glass neg holder to a large metal heat sink
>and some how cool it with ice. I do expect this would be a disposable
>copy neg for my process.

 A fan is probably better than ice.

>What UV source are you trying to use? i figured the sun would pump a lot
>more UV than any light source.


 Some lamps make  a lot of UV.  There are enough persons who
have received bad UV burns who will testify to it (Especially bad for the
eyes in high doses.)  Try an HQL lamp, but use the appropriate
ballast.  These screw into normal sockets but will die instantly if
connected directly to the power line unless you have a type designed for
such service (some include a normal lamp in the same glass envelope to
serve as the ballast, but I would avoid these!)

You would break the outer envelope being careful not to damage the inner
parts, which include a high pressure, quartz, mercury vapor bulb.  Quartz
passes the UV.  You must NEVER look at this for extended times without a
filter against UV exposure to your eyes and skin.  A piece of conventional
glass will remove most of the problem UV while leaving the useful stuff.  I
believe you can also buy versions of this lamp without the fluorescent
coating and then it is better NOT to remove the outer envelope.  This may
be harder to find.  IMPORTANT details: 1) Never touch the bulb or clean
well if it accidently happens.  The bulb becomes very hot and the dirt
(oil, salt) from your skin will burn on and speed the failure of the lamp.
2) these bulbs can explode and throw hot quartz all over.  Use a shield to
contain the pieces in case it happens.  I have used a laboratory beaker for
this but something thicker would be better, and I suggest metal in every
direction except the way to the film, condenser and whatever.  3) The lamps
contain mercury and if one explodes you should have a system to vent the
vapor outdoors and trap any liquid (the shield should be able to do
this.)  You take a grave risk by not protecting you and everyone else from
such a source.

Can you not hold the fabric flat during a contact
exposure!  You can then enjoy the full power of the sun.

Good luck, and think about safe methods.  There is little danger if you
stay clever.

Bob

>Thanks
>
>Mac
> >      Also to enlarge to that huge size will require a very long exposure
> >and you may find that the film can not handle the infrared heat as light
> >fall off increases dramatically the larger you go......... On my project I
> >am trying to find out how to increase the speed of dichromate sensitized
> >paper to reduce the time I need to expose... If you come across any
> >information on this  I hope that you would pass that along to me...
> >      I imagine you can just set up a standard  medium format enlarger
> >rigged with " first surface" mirrors to channel the  sun light into the film
> >chamber into a dark room or box  if you are setting up a daylab deal you
> >would have to block all light fom the film plane down to the paper plane
> >......I would not use the condensers as they too will block the UV as well
> >as standard mirror....
> >      Now you know everything that I know.. Good luck... Send me a picture
> >of the thing when it is built....
> >Regards,
> >John Cremati


from camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
Subject: Re: [Cameramakers] Surplus Military lenses??
Date: Fri, 9 Aug 2002 

....
 As far as a glass negative holder , again , regular glass is a
powerful UV filter....I would go to Optical white glass that is listed below
for your negative holder. ( It may be the glass that Nikon uses in their
lenses.....)  You may  want to try a sandblasted  upper glass on the holder
to act as a diffuser.. I think it may cut down the light output , but would
give a more even distribution........Try it both ways..
       Here is a dealer that sells the Schott Optical White Glass B270, It
comes in all thickness.   It supposedly has a very high UV transmission rate
comes in large sheets and is reasonably priced .  It would be good for large
contact frames,  film holders ect..

http://www.howardglass.com/B270.html


       The light source I  will be using is a 5000 to 10,000 watt pulsed
xenon light head....Supposedly a good source of UV... I am just going to use
a  blower fan to keep things cool...

Happy Trails,
John Cremati
...


From: Uncle Al UncleAl0@hate.spam.net
Newsgroups: sci.optics,sci.physics
Subject: Re: Fluorescent optics
Date: Mon, 26 Aug 2002


Bruce Bowen wrote:
>
> Would it be possible for people to see into UV with fluorescent
> optics? For example contact lenses, eyeglasses, etc.  I believe the
> material would have to fluoresce somewhat coherently with the incoming
> UV, and not just scatter randomly in order to be able to image
> effectively.

The natural lens oin your eye is a potent UV absorber.  Young lenses
cut off at 400 nm.  By middle age the lens is distinctly yellow, then
it shades to brown.  Middle-aged folks confuse black and blue socks
and shoes, especially under incandescent light.  Old farts without
cataract extractions dress in weird bright colors.  Old ladies'
makeup, if they retain OEM lenses, looks like clown school homework.

Without the lens you can see to at least 380 nm or so, past
blacklight.  UV eats your retina.

If you want to look into the UV or NIR, use a camera.

--
Uncle Al
http://www.mazepath.com/uncleal/



From: dgoncz@aol.comp.mil ( Doug Goncz )
Newsgroups: sci.optics
Date: 05 Sep 2002 
Subject: Re: Fluorescent optics


>From Yves Le Grand, "Light, Color, and Vision", 1957:

"The Effect of Ultraviolet Light on the Eye"

The retina is normally protected from ultra-violet radiation by the lens of the
eye, but in the case of aphakics the far ultra-violet can cause retinitis with
alteration in the perception of green.

The lens of the eye fluoresces when irradiated by ultra-violet lgiht, and emits
radiation having a continuous spectrum up to 0.6 mu, with a maximum energy at
about 425 m-mu..... To the subject himself, the fluorescence is completely out
of focus.... Self-fluorescence of the retina, on the other hand, would permit
vision in the ultra-violet, even though the retinal elements were insensitive
to the ulta-violet. Such retirnal fluorescence was beautifully demonstrated by
Helmholtz. He illuminated with ultra-violet light, a white piece of porcelain
wich was diffusing and non-fluorescent, and a freshly dissected human retina;
he observed the two surfaces through a quartz prism in such a way that he saw
side by side the ultra-violet image of the porcelain and the image of the
retina corresponding to the the fluorescence alonee; so Helmholtz deduced that
vision in the ultra-violet consists of two superimposed phenomena, fluorescence
of the retina, which gives a greenish blue, and true vision of the
ultra-violet, wihch is seen like the violet at the end of the visible spectrum;
the combination of the two produces a lavender -grey colour which is actually
what one sees. (One of the longest sentences I"ve ever read!)

If a quartz lens were inserted as for cataract replacement, it seems
ultraviolet vision, and retinitis, would be available. Ouch.

More:

Fluorescence is also considered to be the cause of the luminosity observed, in
total darkness, if a readiactive source emitting Beta-rays is near the eye. It
is not impossible, too, that the fluorescence of the ocular media plays some
part, even when the exciting radiation is at the violet end of the visible
spectrum. Fedorov (1936) explains in this way the irregularities which are so
frequently observed in the curve of relative luminous efficiency at the short
wave-length end of the spectrum.

Yours,
Doug Goncz, Replikon Research, Seven Corners, VA 


From: Phil Hobbs pcdh@us.ibm.com
Newsgroups: sci.optics
Subject: Re: UV pass filter?
Date: Thu, 05 Sep 2002 



Bob May wrote:
>
> Stacking with a UV pass filter is an acceptable method of doing this unless
> you have a problem sending the light through two filters.
> One handles the fine detail and the second handles the out of band problems.
>

One other possible problem is filter fluorescence--filter glass is
sometimes used as a standard fluorescent source.  You may find that your
results depend on the order in which you place the filters.

Cheers,
Phil Hobbs



From camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
Subject: Re: [Cameramakers] Computar Lenses
Date: Thu, 12 Sep 2002

Does your brochure give any specifications as to resolution , lines per 
inch, number of elements ,  ect?  The Computars are considered  sleepers 
because  they are a quality lens that you can usually buy very 
cheap....There was a write up on them ( I don't remember the magazine } 
a number of years ago that made the claim of extremely high resolution, 
fully color corrected apo design..........

    From what I understand , Most El-Nikkor Lenses are 6 element coated  
lenses, made with special optical glass ( even the older chrome models 
from the 1970's ) that will pass Ultra Violet light...


From: brianc1959@aol.com (brian)
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Canon UD and Fluorite elements?
Date: 8 Oct 2002


"Max Perl" max_perl@post11.tele.dk wrote...
> Aha.....
> Do you know what glass Nikon uses in their 105mm UV lens?
> Would they have any benefit of using flourite glass in this lens?
> Do you think Carl Zeiss uses flourite glass in their super archromats?
>
> Max

Max:

The Nikon UV lens is discontinued, but it was made from fused silica
and fluorite.  These are the only two practical materials that are
transparent into the deep UV.  Fortunately, they can be combined to
achieve a wide-band apochromat ranging from about 250nm in the UV all
the way to about 650nm (red) in the visible.

I'm not familiar with the Carl Zeiss super apochromat you mention, but
if it is intended for true UV below 350nm then it undoubtedly uses the
same two materials.  For ordinary visible apochromats I imagine that
Zeiss uses either Schott FK  or Hoya glasses.  In fact, the last time
I visited Zeiss in Jena I was surprised to find out that they
preferred Hoya glass because of reduced cost!

Brian


From SLR Manual Mailing List:
Date: Mon, 21 Oct 2002 
From: Allan Ostling aostling@aaahawk.com
Subject: RE: Pentax 85mm f4.5 Ultra-Achromat


I found a website which answers my own question,
http://212.187.14.19/index2.html. This is a lens designed for
ultraviolet photography. No wonder I never heard of it before.



From: AC/DCdude17 JerC@prontomail.com
Newsgroups: rec.photo.equipment.35mm
Subject: Re: infra-red & ultraviolet film
Date: Wed, 13 Nov 2002


    http://msp.rmit.edu.au/Article_01/08.html

If you use HP5  with fused quartz lenses you can probably get a good
result.  Who knows how much a lens would cost if all the elements were
made of fused quarts though.

ken@usenet.ca wrote:

> I know that we have infra-red film, but is there a film for the low
> end of the light spectrum, the ultraviolet at less than 400
> nanometres? Is such a thing feasable? Would it be useful in any way?
> Ken



From: Mark Roberts mark@robertstech.com
Newsgroups: rec.photo.equipment.35mm
Subject: Re: infra-red & ultraviolet film
Date: Thu, 14 Nov 2002 


Robert Feinman robertdfeinman@netscape.net wrote:

>ken@usenet.ca wrote:
>> I know that we have infra-red film, but is there a film for the low
>> end of the light spectrum, the ultraviolet at less than 400
>> nanometres? Is such a thing feasable? Would it be useful in any way?
>
>One cheap way to try this out is to use a pinhole instead of a lens.
>Combine this with a visible light blocking uv filter (probably gelatine
>or similar).
>Regular film is sensitive to uv.

Don't most lenses block UV though? This has been mentioned many times in
threads debating the use of UV filters. A friend of mine has a special 100mm
Nikon macro lens with quartz glass, specifically for photographing under UV
light.

For those who wonder why he might want to do this: He says it shows bite
marks really well. (He's a forensic pathologist.)
--
Mark Roberts
www.robertstech.com
Photography and writing


From: Michael Quack michael@photoquack.de
Newsgroups: rec.photo.technique.misc
Subject: Re: UV/Black Light photography: tips?
Date: Sun, 22 Dec 2002

zeitgeist says...

> blacklight photography is an esoteric specialty,
> lenses don't transmit UV well,

Er...... I think you are completely on the wrong track.
He wants the effect of blacklight triggering fluorescence
in certain materials. The light starting this effect is
UV, but what he captures is regular colored light.

Stuff like this:
http://www.photoquack.de/beauty/08.htm
http://www.photoquack.de/beauty/17.htm  
Simple. He needs longer shutter speeds because the
luminescence is not too bright, and he needs some
sort of very diffuse basic light to fill but not
kill the fluo effect. Tripod and a non-moving subject
are best for this. Make sure the fill is daylight
balanced or flash.

--
Michael Quack michael@photoquack.de


From camera makers mailing list:
Date: Sun, 2 Feb 2003 
From: DONALD MILLER dnmilikan@sbcglobal.net
Subject: Re: [Cameramakers] Light source for enlarging onto  platinum-paladium
and Kodak Azo papers

John Cremati johnjohnc@core.com wrote:

Hi Donald ,
I also know in the silk screen industry that they have projection
systems where they eliminate the large negatives used to contact print ,
and enlarge right on the coated silk screen.......I have seen just one of
these cameras in a old silk screen catalog but have never tried to research
it any further.. The silk screen process requires a great deal of UV light
as well .. I know that Ulano ( a mfg of silk screen emulsions ) sell a
faster emulsion for the sole purpose of silk screen projection systems
....I do not know if the lenses used on these cameras are quartz or EL
Nikkors... I have heard ( not verified ) that these cameras sell for $50,000
..

I have several high output UV lights intended for the silk screen
industry.... . One at 1000 watts, 2000watts, 5000 watts and then the
10,500watt pulsed xenon ... I was intending to experiment on temperatures at
the film plane as well as the enlargement plane once I got the camera set
up as I feel this is going to be my biggest obstacle ..
The process I am most interested in is Carbon Printing which I
believe possibly exceeds platinum as the most beautiful process there is
( only does not have the expense of platinum plus offers a noticeable high
relief quality that is found in no other process)The Fresson Process ,
although secret , is believed to be a form of a carbon printing
process..... The problem with Carbon is that it will be very temperature
sensitive due to the large amount of gelatin used ... . I was thinking of
rigging a series of water cooled tubing to the vacuum frame on the
enlarger and piping it to a photographic chiller that I have.. ... Another
idea is that I would also wash the vacuum frame with the breeze of a
small air conditioner.. And refrigerate the blower air that cools the film
in the light head...

I will photograph the light head on the camera and send pictures off
list if you want me to ..

Regards,
John Cremati


From minolta mailing list:
Date: Thu, 13 Feb 2003 
From: "uosag olaf.ulrich@siemens.com
Subject: Re: Lens Coatings on MD

Roland "rolofung" wrote:
> Just thought about coating on the
> newer MD manual lenses from the
> 80's.  Are they coated to filter
> out UV light?

Yes, they are, and so are the older MD Rokkor and
still older MC Rokkor lenses as well.  The only
exception is the Auto Bellows Rokkor 100 mm 1:4.
This lens has three elements only so despite its
fine coatings, it filters out only part of the
UV radiation.  So on this lens head it makes
sense to use an UV filter on a regular basis.

By the way, it is not only the coatings but also,
and even more so, the optical glass itself that
filters out UV light.  So the more elements a
lens has, the less UV light it transmits.


Roland further wrote:
> If so, would that make a UV filter
> unnecessary for filtering out UV
> rays, and only good for protection?

That's right.  No need to use UV filters on modern
photographic lenses ... where 'modern' means: from
the 1960s or later.

The exception to this rule is when the level of
UV radiation is extremely high in relation to the
visible light.  This usually is the case at the
sea-shore and in the high mountains above, say,
8,000 ft/2,500 m.  Under these circumstances, it
can make sense to use an UV filter even on modern
lenses, particularly on slow prime lenses with a
low element count---but only unless you use any
other filter (like a polarizer, skylight, or some
contrast filter) since these have the UV filter
effect built-in.


Regards,
Olaf
--
Olaf Ulrich, Erlangen (Germany)
olaf.ulrich@onlinehome.de


From minolta mailing list:
Date: Thu, 13 Feb 2003 
From: "Dave Saalsaa" SaalsD@cni-usa.com
Subject: Re: Re: Lens Coatings on MD

Leica has a UV absorbant  filter in the cement for their lenses with
compound elements.  This UV absorbant cement is called  Aborbine.  Lenses
that didn't have compound elements, (two or more elements cemented together)
had to rely on lens coatings similar to Minolta.

Dave Saalsaa



From: Peter Irwin pirwin@ktb.net
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Enlarging limitations
Date: Sun, 16 Feb 2003

David J. Littleboy davidjl@gol.com wrote:

> Even worse, even without a filter, all UV will do is _reduce_ resolution,
> since the lenses that real people use aren't all that well corrected for
> near UV relative to red.

My Leica Manual (11th ed) says that ultraviolet light from a
blacklight is useful for making detailed photographs of insects
(as well as showing that some have distinctive ulatraviolet markings)
I suspect that an uncoated elmar might be better at this than some more
modern lenses, but I did find it interesting.
(From the Leica manual 11th ed p.380-382.)

Peter
---
pirwin@ktb.net


From: hemi4268@aol.com (Hemi4268)
Newsgroups: rec.photo.equipment.medium-format
Date: 16 Feb 2003
Subject: Re: Enlarging limitations



>My Leica Manual (11th ed) says that ultraviolet light from a
>blacklight is useful for making detailed photographs of insects

Yes if anyone has played with a black light, they will notice they can see if
it's on or off by the deep blue glow.  The wavelength distribution range is
between 360 to 460.  Seems the cutoff for sight is around 420.

My point is, noon summer sun not only has lots of uv but also blue visible
light. If you think about it, lenses will have about 20% better performance
during blue wavelength summer months then red wavelength winter months.

If anyone ever built themselves an optical bench that can be used outdoors,
they can have fun doing lens tests both in the winter and summer months.  I
assure you, the data will be very interesting.

Larry


From: "Larry" sales@nobodyshome.com
Newsgroups: sci.optics
Subject: Re: Need Mirror Coated -  UV enhanced Aluminum
Date: Fri, 1 Nov 2002


"Michael" mbush@deletethis.maine.rr.com wrote 
> if the tolerances on the 1.5x2.5 aren't too tight,  the easiest method may
> be to just buy an oversized mirror and take it down to your local glass shop
> to have it cut to size...  Last one I did cost me  $3


But don't count on getting much reflection below 3500 Angstroms. Most
mirrors are not good UV reflectors, unless specifically designed to be.

Larry


From nikon mailing list:
Date: Thu, 27 Feb 2003 
From: Randy Holst mrvolvo@cableone.net
Subject: Re: Re: UV Nikkor lens

"Mike \"vK\" Kovacs " wrote:
>
[snip]
> > "The reason for the special UV lens is to get visible light and UV
> > to come to focus at the same point."

> I would take issue with this last statement. The purpose of the
> special lens is to indeed have the capability to even transmit UV
> light. 

You're right and my response was oversimplified. The point I was trying
to make was that it's not the lens itself that restricts light
transmission only to UV, but the special black filter that comes with
the lens.

> Regular glass more or less absorbs UV which you'll probably
> learn when you try out your UV filter. 

Right again, but my research into this area indicates that enough UV
will pass through the lens to accomplish my purpose. My purpose BTW, is
to take B&W; UV photos of personal injuries to reveal bruising which
would otherwise be invisible under visible light. The filter of choice
for this purpose is supposed to be the Kodak Wratten #18A, but it must
be special ordered from Kodak and is pretty spendy. The B&W; #403 seems
to be the closest inexpensive alternative; about 1/8 the cost of the
#18A filter and 1/100 the cost of the UV NIkkor. 

For examples of this type of photography, see:
http://www.crime-scene-investigator.net/uvchildphoto.htm

Randy Holst
Boise, Idaho


From nikon mailing list:
Date: Thu, 27 Feb 2003 
From: Mitch Winkle mitchwinkle@yahoo.com
Subject: Re: Re: UV Nikkor lens

I don't know if you could find what you need, but Edmund Scientific
makes wavelength specific filters in the common lens diameters if I
remember correctly. Maybe they'd have something similar to the pricey
Kodak one.

Mitch


From nikon mailing list:
Date: Thu, 27 Feb 2003 
From: Randy Holst mrvolvo@cableone.net
Subject: Re: UV Nikkor lens

"trstick " wrote:
> 
> I am looking for a discontinued Nikkor 105mm UV F/4.5 AIS lens.

Good luck finding one. I've never even seen one in 30 years of
looking. This probably has a lot to do with it's price; $3450 retail in
my 1995 Nikon catalog.

> Does anyone know whom might have this lens that is designed to transmit
> UV wavelength only.

The last part of your sentence is not quite correct. The lens itself
transmits all light, including UV, otherwise you wouldn't be able to
focus it visually. It comes with a special Nikon UV filter which cuts
virtually all visible light and only transmits UV. The reason for the
special UV lens is to get visible light and UV to come to focus at the
same point.

You can accomplish nearly the same thing by using a regular lens and
adding a B&W; brand #403 Black UV filter, which costs $36.50 from B&H.; I
just bought one but have yet to try it out.

Randy Holst
Boise, Idaho


From nikon mailing list:
Date: Thu, 27 Feb 2003 
From: Mike  Kovacs mike-kovacs@shaw.ca
Subject: Re: UV Nikkor lens

snip...
"The last part of your sentence is not quite correct. The lens
itself transmits all light, including UV, otherwise you wouldn't be
able to focus it visually. It comes with a special Nikon UV filter
which cuts virtually all visible light and only transmits UV. The
reason for the special UV lens is to get visible light and UV to come
to focus at the same point."

I would take issue with this last statement. The purpose of the
special lens is to indeed have the capability to even transmit UV
light. Regular glass more or less absorbs UV which you'll probably
learn when you try out your UV filter. Quartz and fluorite are two
materials that can transmit UV and I believe this lens uses one or
both.

Bjorn Rorslett has a cool article on his site. Apparently, some of
the best homemade UV lenses are the single coated 28 mm f/2.8 E, 35
mm f/2.5 E, and 100 mm f/2.8 E E series, if you remove the coating
off the front and rear elements. (good thing they are cheap!)

http://www.naturfotograf.com/UV_IR_rev00.html - see page 7 for
details on "lens grinding"


From nikon mailing list:
Date: Thu, 27 Feb 2003 
From: Rick Housh rick@housh.net
Subject: Re: Re: UV Nikkor lens

Mike Kovacs wrote:

>The purpose of the special lens is to indeed have the capability to even
>transmit UV light. Regular glass more or less absorbs UV which you'll
>probably learn when you try out your UV filter. Quartz and fluorite are
>two materials that can transmit UV and I believe this lens uses one or
>both.

I seem to recall we had a thread on this here a couple? of years ago, and
the ultimate conclusion seemed to be that the materials used to cement the
elements of some "ordinary" lenses together, plus some modern coatings,
tended to absorb most or all the UV light. I can't seem to locate the
thread in the archives now, though. Anyone remember it?

- Rick Housh -


From nikon manual mailing list:
Date: Thu, 27 Feb 2003 
From: "Mike \"vK\" Kovacs  I seem to recall we had a thread on this here a couple? of years ago, and
> the ultimate conclusion seemed to be that the materials used to cement the
> elements of some "ordinary" lenses together, plus some modern coatings,
> tended to absorb most or all the UV light. I can't seem to locate the
> thread in the archives now, though. Anyone remember it?
>
> - Rick Housh -

Rick: the glass is a pretty big absorber too but by no means does it
gobble all the UV light up. It helps to have a simple lens design
and single/no coating. I guess the real advantage of the UV Nikkor
is that you transmit a much higher percentage of the available UV
than with any glass lens. Just put it in perspective: 10%
transmission = 3-4 stops of UV light loss!

When critical results with UV are required, quartz is the way to go. 
During my graduate studies I was measuring the kinetics of some
chemical reactions on a UV-Visible spectrophotometer using a
temperature controlled quartz flow cell of my design. Our glass
blower REALLY hated me for tasking him to join quartz and glass
together: not fun!


From nikon manual mailing list:
Date: Thu, 27 Feb 2003 
From: Randy Holst mrvolvo@cableone.net
Subject: Re: Re: UV Nikkor lens

Mitch Winkle wrote:
>
> I don't know if you could find what you need, but Edmund Scientific
> makes wavelength specific filters in the common lens diameters if I
> remember correctly. Maybe they'd have something similar to the pricey
> Kodak one.

I already checked there and the closest thing they had was an unmounted
2" square Schott UG-1 band-pass filter (around 300~400 nm.). The B&W;
#403 I bought is supposed to be the equivalent, mounted in a 52mm filter
ring, and was cheaper. All I gotta do now is find the time to do some
tests with film so I can learn how to get predictable results.

Randy Holst
Boise, Idaho


From: Nathan Hirneisen [cave_nate@hotmail.com] 
Sent: Sat 2/15/2003
To: speleonics listserve
Subject: [Speleonics] UV LEDs

found a web site for UV LEDs. 
https://www.netdisty.net/ds/L200CUV395/default.asp
InGaN/SiC 
Vf aprox 3.7 volts @ 20mA 
from $2.00 to $24 (for the shorter wavelength) 
you got to sign a release form to buy them. 
was thinking about putting a UV LED in some sort of small flash light case. it would be interesting to see how the minerals and calcite react to UV. which wave length is better for making rocks phosphoresce 370 nM or 405nM . 

thanks, 
Nate


From: "Morpheus, Inc." morpheus@olympus.mons
Newsgroups: sci.optics,alt.lasers,sci.engr.lighting
Subject: Re: possible supplier of very small , low power UV sources?
Date: Thu, 27 Feb 2003 

Ian D wrote:
>
> Folks -
>
> I wonder if anyone has a possible supplier of very small , low power UV
> sources. I have done several web searches but other than some small
> tubes from JKL I couldn't see much at all.
>
> We need the source to emit some energy at between 200 and 300nm - the
> strong mercury line at 253nm is fine - at fairly low input power - say less
> than 1W (we don't have much space or power).
>
> I don't think the new UV LEDs
> can get down to this wavelength yet but I'm happy to be corrected.
>
> I have previously seen small 'bulbs' (used to test a UV flame detector) that
> look for all the world like an orange neon indicator but assume that the
> gas fill is different and that the envelope is quartz.

I believe this to be a Deuterium glow discharge bulb. Philips used to
manufacture those, and they do emit some UV, although if I recall right
not so far down as 200nm. You can search the Philips site for details.

> Another variant on this them seems to be a faint violet discharge lamp
> (original function unknown) - perhaps with an Argon or Nitrogen gas fill.

I am not sure Argon or Nitrogen can output considerably lower than
320-340nm, (but I will gladly stand corrected on this), but OSRAM and
Philips still manufacture glow discharge mini bulbs containing Mercury
that can emit at 253.7nm. In fact, some of them using appropriate
fluorescent coatings are used as night lights.

> Any help on the provenance of these two possible sources or any other
> candidates will be much appreciated

You could also try small gemicidal bulbs at 4 Watts, which are
completely interchangeable with 4 Watt fluorescents or better yet, try
GE's and Philips 4 Watt ozone bulbs, which also emit at 253.7nm and at
194nm. Also, OSRAM manufactures a 10 Watt Ozone bulb, (10 W OZ), which
isn't very small, but doesn't exceed in size the 4 Watt germicidal tube.

> Thanks
>
> Ian D
--
Ioannis
http://users.forthnet.gr/ath/jgal/


From: Rog Rog@Nowhere.net
Newsgroups: rec.photo.technique.misc
Subject: Re: UV/Black Light photography: tips?
Date: Sun, 16 Feb 2003 

It's a mistake to assume that so-called "UV" filters do any more than
the lenses of the camera themselves in reducing UV. It is easy to
demonstrate this by simply taking a long-wave "black light" source and
with the lens removed focus the image of the lamp on a piece of
fluorescent paper. Try various "UV" filters over the lens and you
will see they do little to attenuate near ultraviolet. Nearly all
optical glass severely attenuates the shorter UV range. 

But more to your question, I often photograph fluorescent mineral
specimens under both long and shortwave UV, and most certainly there
are problems with UV "bleedthrough" upsetting the color and contrast
of the image. Fortunately there are effective UV cut filters intended
for this purpose. Look for a "haze 2A" filter, it imparts a slight
yellowish cast but is effective in blocking even longwave UV,
permitting specimens to be seen in all their vivid colors. If the
yellowish cast is a problem it can be easily dealt with in Photoshop
etc. in postprocessing.

For actual UV photography, a quartz or fluorite lens is required, and
they are prohibitively expensive if available at all (the famous
UV-Nikkor comes to mind). These lenses are often used with film that
has been pre-sensitized with citric acid as I recall. A much cheaper
solution that permits photography at least into the near-UV is to
adapt an enlarger lens to fit your camera. The EL-Nikkor and
Schneider Componons are said to have good correction and transmission
into the near-UV (this is accomodate B&W; print processing
requirements). Experimenters also try the older uncoated enlarging
lenses with good success. If you do a search on "UV photography" you
will find many useful articles on how to try this with relatively
inexpensive gear.

I have taken successful UV photographs using a Nikon D100 and a
special UV pass filter (available from Rolyn Optics). Even under
direct sunlight, exposures tend to be quite long, much longer than for
IR photography. UV photos of flowers reveal interesting dark areas in
the center that are completely invisible to normal vision, these
assumed to be forming "targets" for insects.

Vaseline glass glows well under blacklight sources, and is easy to
photograph with the special haze filter mentioned before. Even more
impressive are the many varieties of fluorescent minerals that exhibit
nearly every color hue when excited by various UV sources. You can
see examples of these by searching eBay under "fluorescent minerals."

-Rog

 "zeitgeist" blkhatwhtdog@yahoo.com wrote:
>blacklight photography is an esoteric specialty,lenses don't transmit UV
>well, it is in fact designed to try and filter it out as UV tends to lower
>contrast, why do you think they tell folks to put a UV filter on the lens.
>lenses designed for UV transmition are freakn expensive. IIRC, like
>10grand.
>
>> Does anyone have any tips for photographing ordinary stuff under black
>> lights or other UV sources?
>>
>> I'm looking for tips on mixed UV/visible-light stuff, not pure UV. I'd
>> like to be able to capture the way that parts of the subject seem to be
>> brighter than the illumination would seem to indicate. Obviously
>> incident light metering will be a bit erratic, but how is it likely to
>> affect reflected light metering (e.g. by the camera itself)?
>>
>> The question was inspired by something I saw on eBay the other day. I
>> came across someone selling some "vaseline glass" marbles, and
>> commenting on their weird appearance under black lights - they glow
>> green. A little reading reveals that vaseline glass is glass made with
>> uranium dioxide, so it's a little bit (but only a little bit)
>> radioactive. I'd like to try to be able to photograph the glowing
>> appearance of the vaseline glass (not necessarily marbles), but I'm not
>> sure of the best approach.
>>
>> --
>> "Eagle-eyed" Steve


From: Henry Schneiker [Henry@HdsSystems.com] 
Sent: Mon 3/3/2003 
To: speleonics listserve 
Subject: Re: [Speleonics] UV LEDs


Nate, 
The LEDs they are offering are in the 390 to 410 range, which for that wavelength is a huge tolerance. If you are looking for a production single LED UV flashlight, you can order one from www.ArcFlashlight.com (or one of their dealers) for $45 - takes a single AAA battery and is waterproof. They use a sorted bin with a range of 390 to 395 and a minimum output. No UV paperwork required. While supplies last as they will no longer be manufacturing them after the current supply of LEDs runs out. 
Henry. 

On Saturday, February 15, 2003, at 08:49 AM, Nathan Hirneisen wrote: 
found a web site for UV LEDs. 
https://www.netdisty.net/ds/L200CUV395/default.asp 
InGaN/SiC 
Vf aprox 3.7 volts @ 20mA 
from $2.00 to $24 (for the shorter wavelength) 
you got to sign a release form to buy them. 

was thinking about putting a UV LED in some sort of small flash light case.
 it would be interesting to see how the minerals and calcite react to UV. 
which wave length is better for making rocks phosphoresce 370 nM or 405nM . 

thanks, 
Nate 


From: sjnoll@big-list.com (Steve J. Noll)
Newsgroups: sci.optics
Subject: UV Enhanced Aluminum mirror recoat- followup.
Date: Fri, 10 Jan 2003 


A couple months ago I posted a request for recommendations
for a coating service that would do UV enhanced aluminum on a
customer supplied substrate.  I was rehabbing an ancient B&L; UV
monochromator with a small  (~1.5" x 2.5") flat output mirror that was
in sad shape.

After getting a $600 quote from one of those recommended
I did some further searching and found Majestic Optical Coatings
< http://www.majestic-coatings.com > who did it for about 10%
of that.  Now the monochromator works down to 200nm, much better
than I had ever expected.

Steve J. Noll | Ventura California | sjnoll@big-list.com


From: "Ron Gibbs" gibbs.associates@physics.org
Newsgroups: sci.optics
Subject: Re: UV Enhanced Aluminum mirror recoat- followup.
Date: Fri, 10 Jan 2003 

"Steve J. Noll" sjnoll@big-list.com wrote 
> A couple months ago I posted a request for recommendations
> for a coating service that would do UV enhanced aluminum on a
> customer supplied substrate.  I was rehabbing an ancient B&L; UV
> monochromator with a small  (~1.5" x 2.5") flat output mirror that was
> in sad shape.
>
> After getting a $600 quote from one of those recommended
> I did some further searching and found Majestic Optical Coatings
>  http://www.majestic-coatings.com who did it for about 10%
> of that.  Now the monochromator works down to 200nm, much better
> than I had ever expected.

For anyone confused about how production cost can vary by an order of
magnitude. They probably put in your small piece together with many other
components in the coating chamber. The cost of coating is mostly the cost of
a coating run, which is independent of how full the coating chamber is.
Getting a low quote for a one-off coating of a single small piece is a
matter of luck in finding a vendor who has a coating run already scheduled
(and paid for!) with enough space left in the chamber, so you only pay a
handling charge.

regards
Ron Gibbs


From camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
To: cameramakers@rosebud.opusis.com
Subject: Re: [Cameramakers] Light source for enlarging onto platinum-paladium
and Kodak Azo papers
Date: Sat, 1 Feb 2003 

 Hi Donald,
       The El Nikors will pass the UV light in the necessary range... other
lenses will not.. .. There are several threads concerning this on The
Alternative  Photo list...The El Nikors use a special glass that does not
filter UV like the others... We went as far as putting the lens on a UV
spectrometer to see what the readings were along with a few other lenses and
the only one that would pass the nessisary band width  was the El Nikor...
... The information will be on the threads..  I have a old color separation
camera with a 10,500 watt pulsed xenon  light head on it... It has a 1 hp
blower to keep things cool.... I was going it mount a 240mm El Nikor on this
enlarger for the purpose of enlarging directly to make carbon prints..
..................

Also for  glass  film carriers here is some specs on Shott glass...( this
may even be the glass that is used in the El-Nikors...
John Cremati


For those who are really interested in the exact physical and chemical
properties of a sheet of glass with a high UV transmission :
0%   at 280 nm
14% at 300 nm
65% at 320 nm
85% at 340 nm
>90% from 360 nm and higher. thickness 2.0 mm

you can e-mail to michael.quidde@schott.com and ask him for the
specifications of Schott B270 superwite crown glass.He will send you a large
attachment (~800 kB) to his answer.

The internet address of an U.S. supplier is
http://www.howardglass.com/B270.html
Erich


From camera makers mailing list:
From: "John Cremati" johnjohnc@core.com
To: cameramakers@rosebud.opusis.com
Subject: Re: [Cameramakers] Light source for enlarging onto platinum-paladium
and Kodak Azo papers
Date: Sat, 1 Feb 2003

  Donald,

       Here are some of the treads on the discussion of UV transmission 
thru El- Nikor glass from the Alternative Photo list.. I hope this will 
help...

         Please keep me informed of your progress as I am extremely 
interested.  I kind of dropped the ball after getting this  information 
and have still not hooked up my enlarger..

        I will measure the spacing on the pulsed xenon bulbs..  I 
believe there were four in parrell  close to a ground glass for 
diffusing  and  then there were two  longer  more powerful tubes .. 
crossing  behind the 4 that were  perpendicular forming a checker 
pattern. ... I do not think that these  bulbs were on for any length of 
time as they were intended to expose ortho film which I believe has a 
ASA rating of about 5 or so  and at 10,500 watts , that would not take 
long.. .....

        I think the infrared will be a problem on long exposures... I 
was considering rigging some sort of Air conditioning system for the 
film chamber as I do not know if the fan will be enough...

        The enlarger will handle up to 11x14 negatives and has a 30x40 
vacuumed frame for the enlargements ..

       .It is 10 feet tall and weighs 3000 pounds..(.This is probably 
the main  reason that I have not hooked it up yet..)

   John Cremati

......................................................
  > Scientific graphics supply catalog that all Nikon El Nikor Enlarging
  > Lenses were made of a special optical glass to allow passing of UV
  > waves between 350 and 450 nm.. I have also read of Sun enlargers
  > utilizing sunlight as the light source thru a lens to enlarge during 

  > the turn of the century in the book "Keepers of Light "...

  Bit lefthanded! If you compare BK7 and UBK7 at 350nm, the difference
  .......................................................
  Here's some interesting information I picked up from a Nikon Catalog
 about their enlarging lenses:

  EL-Nikkor enlarging  lenses are corrected for chromatic aberration
  beyond the visible spectrum into near ultraviolet wavelengths --
  wavelengths to which photographic papers are particularly sensitive.=20
  Through the use of special optical glass and matching optical
  coatings, EL-Nikkor lenses are designed for ultraviolet transmission
  in the 350 to 450 nm range. This means EL-Nikkor enlarging lenses can
  be used for color separation in addition to all other enlarging
  applications. EL-Nikkor lenses are also front threaded to accept screw
  in accessories , and can be used for exceptional small-object
  photography when mounted on a bellows.

  These enlarging lenses don't have the spectral transmission of a true
  UV quarts lens, but then again they don't cost $3000 US dollars like
  Nikon's quartz lens.


  .......................................................
  Folks:
    I put a relatively new El-Nikkor 210 lens in the path of my UV
  spectrophotometer today, and am happy to report that the lens passes pretty
  well all UV radiation above 350 nm. In Comparison, my Fuji 300mm LF lens
  began to cut UV at around 400 nm, and showed strong absorption by 380 nm.
  This makes sense, as plain old plate glass shows similar trends. 

Cheers,
  Ed Stander



[Ed.note: an odd item, but also a reminder on glass transmission in IR, 
an issue with #18a UV filter, as one example...]
From: brianc1959@aol.com (brian)
Newsgroups: sci.image.processing,rec.photo.technique.misc,rec.photo.equipment.35mm
Subject: Re: 1.55um photographic film
Date: 16 Mar 2003 

Pard Pardoo@nitwit.net wrote 
> At this low an IR frequency, even optical glass is opaque. You're in
> for Indium lenses and thermal imaging at this wavelength.

Nearly all optical glasses have excellent transmission at 1.55
microns, many having less than 1% absorption in a piece of material
25mm thick. Coatings and aberration correction are likely to be more
of a problem than internal transmission.

Brian
www.caldwellphotographic.com


[Ed. Note: thanks to Bill for sharing these notes on quartz lens uses!]
From: Bill Brickell [tatand2@cox-internet.com] 
Sent: Mon 4/7/2003 
To: Monaghan, Robert 
Subject: lens adapter

Bob, 
I emailed SRB.They got right back to me.At this time they say there is no such adapter to update the M42 
screwmount body to Contax/Yashica or anything else.They can make one for 70 pounds.You are right, I can get 
either another bellows for Contax or a spotmatic for that price. I mainly got the screwmount bellows for the exotic 
lens to do ultraviolet work with.At the time the M42 bellows came up it was inexpensive and a Contax bellows was 
unavailable.I see the Contax bellows available from time to time and I will have automatic functions with it.My main 
interest was to adapt the bellows I specificlly bought for the exotic lens for occasional use with the Zeiss lenses.
Now that I have an quartz lens I will most likely just do UV with it instead of my glass lenses.I have experimented 
with glass and quartz now and I can tell you that having a lens corrected for the UV range is helpful. My glass lenses 
and quartz lenses record longwave uv at roughly the same shutter and F combinations. It takes just as long to get a 
useable inage with the quartz lens and 18A or U-360 as it does the glass.You just don't have to re-focus. It is quicker 
with tungsten balanced films as you are not burning through a UV stopping layer. 

Bill


From: Andrew Resnick andy.resnick@NOSPAM.grc.nasaDOTgov
Newsgroups: sci.optics
Subject: Re: Non-Visible UV light questions..
Date: 15 Apr 2003

> Ok, first things first: From
>
> http://www.cliffshade.com/dpfwiw/filters.htm#ir

Actually, a quick look around found
http://www.naturfotograf.com/uvstart.html

which is better. Sorry!

Andy
Andrew Resnick, Ph. D.
National Center for Microgravity Research
NASA Glenn Research Center


From: Andrew Resnick andy.resnick@NOSPAM.grc.nasaDOTgov
Newsgroups: sci.optics
Subject: Re: Non-Visible UV light questions..
Date: 15 Apr 2003 

some dude wrote:
> Hi-
>
> I shoot a lot of UV non-visible photog. with a digital camera, 18A
> uv-blocking filter and a hot mirror (to get rid of the rest that it
> doesn't block and to get rid of UV "haze").
>
> I am curious, optically, when I shoot photos that whites come out
> blue, greens come out brown, and a lot comes out purple or red. etc
> etc
>
> If someone could either answer this question, or point me to a
> resource, it would be much appreciated. My main goal is find to find
> out how all colors (when shot non-visible) turn out. I suppose I
> could run some tests...probably will...

Ok, first things first: From

http://www.cliffshade.com/dpfwiw/filters.htm#ir

The Wratten 18A filter is a UV *pass* filter, not a uv block filter. The
hot mirror is to block some residual tansmission in the NIR. The
cameras listed on the site are being exposed to the UV-A band (320-400
nm). It's a very good site, and I recommend you read it, if you haven't
already.

So the other question is how the camera assigns colors to this very
narrow spectrum, and I don't know the answer to that, other that the
standard answer "Just because something looks green in the visible
doesn't mean it looks green in the infrared, or ultraviolet." Again, the
website has a decent reference section at the bottom that may be of help.

Andy
--
Andrew Resnick, Ph. D.
National Center for Microgravity Research
NASA Glenn Research Center


From: some dude some@dude.net
Newsgroups: sci.optics
Subject: Non-Visible UV light questions..
Date: Mon, 14 Apr 2003

Hi-

I shoot a lot of UV non-visible photog. with a digital camera, 18A
uv-blocking filter and a hot mirror (to get rid of the rest that it
doesn't block and to get rid of UV "haze").

I am curious, optically, when I shoot photos that whites come out
blue, greens come out brown, and a lot comes out purple or red. etc
etc

If someone could either answer this question, or point me to a
resource, it would be much appreciated. My main goal is find to find
out how all colors (when shot non-visible) turn out. I suppose I
could run some tests...probably will...

Thanks!
-sd


[Ed. note: possibly also use for a UV light source for macro or other projects?]
From camera fix mailing list:
Date: Mon, 12 May 2003 
From: rolohar@aol.com
Subject: Re: Yellowed lenses

jbrokaw@pacbell.net writes:
> At the cost to clear it up, this seems like a good
> solution to the 'yellowing problem' -- much more satisfactory than the
> 'internet' solution involving the sledgehammer...!

I just noticed that there are some LED's available that emit UV energy in the
396 nm region that might be good for making a small cylindrical device that
would fit directly over the lens, containing 4 or 5 of these LED's for a
really effective radiation device. A small power supply would be needed. The
LED's have a 30 degree beam pattern, and of course would not subject the lens
to a temperature rise very much above ambient.

All Electronics
www.allelectronics.com
1-800-826-5432
stock # ULED-2
$1.75 each

Roland F. Harriston


From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.optics
Subject: Re: Black UV light lasers
Date: Wed, 14 May 2003 

Danny Rich wrote:
>I do not know what ANSI standard this came from but every where else in
>the radiometric world these wavelengths (180nm to 280nm) would be
>considered deep UV. This is in the range of ionizing radiation is VERY
>dangerous to human vision. UV is normally classified as follows UV-A, 
UV-B and UV-C, with some overlap in the boundaries. UV-A will cover from
>about 400nm down to about 350nm,

Upper limit is borderline violet-UV, usually 400 nm
Lower limit is 315 nm for USA CDRH, sometimes otherwise 320 nm

> UV-B is from 350nm to 250nm

I always hear either 280-315 nm or 286-320 nm

> and UV-C is from 250nm down to 150nm.

UVC is, depending on who you ask, either all UV of wavelength shorter
than the UVB range (which means 10 to either 315 or 320 nm) or the subset
of such UV that is at wavelengths linger than "vacuum ultraviolet"/"VUV",
often understood to be such of wavelengths around to longer than 200 nm.

> Some times the boundary of UV-C is adjusted to move the 265nm
>mercury line down into UV-C because it is so dangerous.

By every definition that I ever heard, 265 nm is UVC and never anything
other than UVC. But a mercury lamp that produces 265 nm normally produces
a lot of UVB (a few wavelengths usualy with the strongest being a
narrow cluster at 313 nm) and long-half-of-UVA, as in
not-so-skin-affecting UVA (namely and largely specifically 365-366 nm).

>Danny Rich

- Don Klipstein (don@misty.com)
>> UV is considered 0.180 to 0.280 um according to ANSI. The maximum "safe"
>> (again according to ANSI) exposure over an 8 hour period is 9.6 x 10 ^-9
>> watts. UV is not a "safe" wavelength. Anything over 0.5W is considered
>> a class 4 laser device and requires the appropriate controls so people
>> are not injured.
>>
>> As for sources, quadrupled YAG, Argon, Helium-Cadmium and Krypton. None
>> are cheep and some have other hazards.
>>
>> Don't forget UV causes sunburns so if you buy one of these things stock
>> up on sunscreen.
>>
>> P. Danek
>>
>> Radium wrote:
>>
>> > Hi:
>> >
>> > Would any of you folks be able to help me as to where I can find UV
>> > black light lasers? (any particular store, website, company???)
>> >
>> > I am looking for laser of this frequency which gives out the correct
>> > brightness of light as to have a harmless *yet* perceptible effect on
>> > vision.
>> >
>> > Big thanks,
>> >
>> > Radium



From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.optics
Subject: Re: Black UV light lasers
Date: Wed, 14 May 2003 

Bill / Repeating Decimal wrote:
> Ian Stirling at root@mauve.demon.co.uk wrote:
>
>> Looking up the table I have, I see that 380nm is about 1% as visible
>> as 442nm.
>> (blue sensitivity drops with age)
>
>If true, that is interesting. I find it difficult to believe that the
>visual pigment changes molecular form with age. Is there less of it? Do
>transparent parts of the eye, such as lens with a cataract, absorb it?

Lens of the human eye without the traditional cataracts sometimes
becomes more yellow/brown with age. This is often something known either
as "nuclear cataract" or "nuclear lens change". In this case, "nuclear"
refers to the central portion of the lens of the eye as opposed to a
source/type of offending radiation.

The offending radiation is usually mainly UVA (near/below 400 nm down to
approx. 315 nm) and this effect occurs mostly in people with outdoor jobs
- especially farm workers in tropical/subtropical latitudes and
secondarily long-haul truck drivers, as far as I remember from literature
that I read in this area a good 16-18 years ago.

- Don Klipstein (don@misty.com)



From: "Robert Levin" robert.levin@sylvania.com
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Tue, 17 Jun 2003 
"PV" psivasamy@hotmail.com wrote 
> Hi,
> I am using UV LEDs, and I don't see any safety standards for the UV
> range (eye protection for users). Where can I get these unfo. I would
> appreciate any pointers.
>
> Thanks in advance,
> Prem

The appropriate standard for evaluating hazards is ANSI/IESNA
RP-27.1-96, "Recommended Practice for Photobiological Safety for Lamps
and Lamp Systems - General Requirements". This document includes
references to the pertinent scientific literature.

Other relevant documents are:

ANSI/IESNA RP-27.3-96, "Recommended Practice for Photobiological Safety
for Lamps - Risk Group Classification and Labeling"

ANSI/IESNA RP-27.2-00, "Recommended Practice for Photobiological Safety
for Lamps and Lamp Systems - Measurement Techniques."

- Bob


[Ed. note: thanks to Don Klipstein for sharing these notes and URL pointers..]
From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Wed, 18 Jun 2003

Big John wrote:
>I wouldn't agree with that! I have some 395nm UV LEDs I purchased from
>All Electronics a while back. These are right on the edge of UVA and
>deep violet. The human eye can't see much below 400nm. The data sheet
>has a very clear warning on it. There are also UV LEDs with wavelengths
>of 375nm, 370nm, and 350nm with a fair amount of optical power.

If you know of any 350's that put out much more than 30 microwatts of
optical output, please let us know!

> From what I've read from different sources direct exposure (looking
>directly at the LED) can damage your eyes in less than a minute. It can
>cause burns on the outside of the eye (like sunburn),

Based on the lack of significant output at shorter wavelengths (below
350 nm), I would say no.

> cause premature cataracts,

If you stare into them at close range for some horribly long period of
time. If you look at the sky while in sunlight in an open area, your eyes
can get UV exposure of a couple to maybe a few milliwatts per square
centimeter and a fair fraction of a milliwatt can enter even a
constricted pupil. Most UV LEDs have total output (at rated "typical
current") anywhere from .75 to 12 mW. Daylight causes cataracts more
easily than a UV LED more than something like 2 inches away from your eye
does.

>and even damage the retina at the back of the eye.

I am concerned here. I have calculated from laser safety standards that
if you stare into a UV LED with fully dilated pupils, damage in as little
as 10 seconds may be possible with higher output narrowbeam ones at closer
range. You won't damage your eyes accidentally looking into them for a
second or two.
Visible violet is not much better than UV, and blue is not much better
except it will constrict your pupils more and more quickly. Many blue
and green LEDs with chip chemistry like that of UV ones come with warnings
not to stare into them due to the intense light.

Although staring into these LEDs is not recommended, it is normally safe
to stare at objects illuminated by them.

> Yes, these LEDS do emit some visible purple/pinkish light, but they are
>much brighter in the UVA area that your eye isn't sensitive to - so use
eye protection. You can't replace your eyes!
>
>As far as protective glasses go check out the type used for UV dye
>checking of automotive air conditioning systems

Often the purpose is just contrast improvement. Some of those lights
have a fair amount of visible violet and/or visible blue light that
are blocked by the yellow glasses. I know that at least some of those
glasses are yellow and that most of those lights won't hurt your eyes
unless you stare "down the barrel".

>or ask your eye doctor what he/she recommends.

I know an eye doctor that once had a sign in his office warning that the
thinning of the ozone layer would cause an increase in incidence of
UV-related macular degeneration (a form of retinal damage). But the only
UV wavelengths that reach the retina are unaffected by even a healthy
ozone layer. It seems to me that the schools that eye doctors go to don't
get into ultraviolet to the extent necessary for their graduates to know
everything about every UV source (even less so for ones that came into
existence since they graduated) and every UV blocking material.

Be aware that UV-absorbing eyewear that is not yellow or amber colored
will pass through most of the output of many UV LEDs. A majority of the
UV from 395 nm LEDs usually passes through polycarbonate, and a fair
amount gets through eyeglasses that have a UV coating. Some "UV" LEDs are
405 nm ones, which are blocked even less by eyewear that is not yellow or
amber. 405 nm, although technicaly not UV, is close enough to have
UV-like effects (mostly from wavelengths 400 nm and slightly longer, even
though wavelengths below 400 nm are also present) and many 405 nm LEDs
come with warnings not to stare into them.

I mention a bit more (although not specifically for LEDs) in
http://www.misty.com/~don/uvbulb.html

My main advice is don't stare into UV LEDs from within their main beams.
I have been playing around with them a lot with no ill effect yet.

>Check out this link for some more specific info and warnings:
>http://ledmuseum.home.att.net/leduv.htm

- Don Klipstein (don@misty.com)


[Ed. note: some notes on sources for UV LEDs..]
From: "Big John" johnengr@nospam.netlabs.net
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Mon, 16 Jun 2003 

I wouldn't agree with that! I have some 395nm UV LEDs I purchased from All
Electronics a while back. These are right on the edge of UVA and deep
violet. The human eye can't see much below 400nm. The data sheet has a
very clear warning on it. There are also UV LEDs with wavelengths of 375nm,
370nm, and 350nm with a fair amount of optical power. From what I've read
from different sources direct exposure (looking directly at the LED) can
damage your eyes in less than a minute. It can cause burns on the outside
of the eye (like sunburn), cause premature cataracts, and even damage the
retina at the back of the eye. Yes, these LEDS do emit some visible
purple/pinkish light, but they are much brighter in the UVA area that your
eye isn't sensitive to - so use eye protection. You can't replace your
eyes!

As far as protective glasses go check out they type used for UV dye checking
of automotive air conditioning systems or ask your eye doctor what he/she
recommends.

Check out this link for some more specific info and warnings:
http://ledmuseum.home.att.net/leduv.htm

Hope this helps,
Big John


From: Chris Carlen crcarle@sandia.gov
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Fri, 20 Jun 2003 

danek wrote:
> Biological damage is dependent upon three things; wavelength, power density
> (power per unit area) and exposure time. Different parts of the eye absorb and
> transmit different wavelengths. While 350nm light is over 90% absorbed by the
> lens it is almost transparent at 315nm. Given a particular wavelength and
> exposure time a laser could cause damage while a light bulb may not since it
> doesn't have the same power density. Lasers and LEDs are far more dangerous
> than bulbs for precisely this reason. They have a much higher power density.
>
> According to the IEC standard 60825-1, the pathological effects of UVA
> (315-400nm) light are photochemical cataracts, skin burn, pigment darkening and
> photosensitive reactions (i.e. if you are on meds that make you sensitive to
> sunlight). The maximum permissible exposure limit for ocular exposure to laser
> radiation at 350nm is 3x10^10 W/m^2 for <10^-9 seconds. So yes you can damage
> the eye at 350nm but I doubt that a light bulb can put out 300 watts per square
> meter at that wavelength. There is still some debate as to whether long term
> exposure to low doses cause damage to the eye, in the form of cataracts, and
> damage to the skin. The moral to the story is if you are using a source that
> can produce of high power density then you have to do some homework to figure
> out if you need to use filters to prevent bodily harm. You can NOT summarily
> say that a particular wavelength of light is "eye safe".
>
> P. Danek


What is this: 3x10^10 W/m^2 for <10^-9 seconds ?

That says to me 30 gigawatts per square meter for less than one nanosecond.

Is this what you intended?

Good day!
--
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA


From: danek danek@ll.mit.edu
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Fri, 20 Jun 2003 
Honest to god that is verbatim what is in the IEC standard. For a 10 second exposure
it is 10^4 J/m^2 at 350nm and for 1000 seconds it is 10 W/m^2.

P. Danek


From: PV psivasamy@hotmail.com
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Fri, 20 Jun 2003

This is the best I have so far found,.....anyone disagrees with this?
Prem

http://www.cdc.gov/niosh/hcwold5e.html

5.2.4.1 UV Radiation

5.2.4.1.1 Hazard location

UV radiation may be emitted from germicidal lamps, some dermatology
treatments, nursery incubators, and some air filters in hospitals.

5.2.4.1.2 Potential health effects

Over-exposure may result in the burning of exposed skin and serious eye
effects. Eye exposure is especially dangerous because the results of
over exposure are not immediately evident. Damage is apparent only 6 to
8 hrs after exposure. Although resulting conjunctivitis can be extremely
painful, it is usually temporary. Long-term unprotected exposure can
lead to partial loss of vision, accelerated skin aging, and increased
risk of skin cancer (NIOSH 1977b).

5.2.4.1.3 Standards and recommendations

No OSHA standard exists for UV radiation exposure, but NIOSH has made
recommendations for UV light in the spectral region of 200 to 400
nanometers (nm). For the spectral region of 315-400 nm, NIOSH recommends
that the total amount of UV radiation allowed to strike unprotected skin
or eyes (based either on measurement data or on output data) be no
greater than 1.0 milliwatt (mW) /cm2 for periods greater than 1000 sec;
for exposure times of 1000 sec or less, the total radiant energy must
not exceed 1,000 mW sec/cm2 (1.0 joule/cm2) (NIOSH 1973b). For the UV
spectral region of 200 to 315 nm, the total amount of UV radiation
allowed to strike unprotected skin or eyes should not exceed the levels
described in the NIOSH criteria documents for UV radiation (NIOSH 1973b).

The following recommendations were developed by ACGIH 1987:
[Ed. note: post ends here..]


From: "Danny Rich" DannyRich@softhome.net
Newsgroups: sci.optics
Subject: Re: Black UV light lasers
Date: Tue, 06 May 2003 

In fact - the blue sensitivity does come back. One of my professors had
cataracts removed one at a time in his late 60s. He used a Munsell
Matchpoint color rule to assess his vision. The distribution of metameric
matches on this rule are well documented as a function of age. Before the
procedure he was way out on the yellow end of the scale. Half-way through
he had one 60+ eye and one 20+ eye. After the procedure he had the same
average match point as a 25 year old.

Danny Rich

"Sam Goldwasser" sam@saul.cis.upenn.edu wrote 
> Repeating Decimal SalmonFly@attbi.com writes:
> > Ian Stirling at root@mauve.demon.co.uk wrote
> > > Looking up the table I have, I see that 380nm is about 1% as visible as 442nm.
> > > (blue sensitivity drops with age)
> >
> > If true, that is interesting. I find it difficult to believe that the visual
> > pigment changes molecular form with age. Is there less of it? Do transparent
> > parts of the eye, such as lens with a cataract, absorb it?
> One effect is that the lens gets more yellow with age so I wonder if that's
> the cause. Get your cataracts removed any perhaps the blue sensitivity comes back.
>
> --- sam


From: westin*nospam@graphics.cornell.edu (Stephen H. Westin)
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: 19 Jun 2003

"Grippin" milo@lightbulbshop.net writes:
> so it is dangerous to enter a club or part that has a 400nm light lighing a
> blacklight poster?
> or to be around a 350 nm blacklight white bulb that is used to cure certain
> materials?

I don't know. I don't know the level or duration of exposure.

> sounds kinda silly to me considering i know customers of mine that are in
> direct contact with these bulbs and i would think 350 nm either from a LED
> or flourescent would be relatively the same.

And who knows, perhaps they are suffering long-term eye damage.

> and Vic i believe is a retired Electrical Engineer, which has nothing to do
> with lighting,

Last I checked, electricity was the dominant means of illumination
over much of the globe. What academic department do you think would
deal with lighting?

> i know he has done much with lighting but the fact that he
> has a degree in Electrical Engineering would point me somewhere else for
> lighting information.

And where is that? The Illumination Engineering Society?

> and regardless of it being flourescent or LED, 350nm is 350nm
> and the 5% you were referring to from my previous posting was the 5% of the
> population that may have the ability of getting 5000 bulbs going at once,
> NOT 5% that go blind.

That's what I was talking about. If someone has the resources to
increase exposure, they are risking their eyes, and possibly those of
others, without proper protection. Do you think the few who do manage
high exposure levels don't matter? Or that somehow they get averaged
out?

> and being under 400nm would not make you go blind,

Please give a reference to the eye-damage data you have that indicate
this. My impression is that 350nm can damage the eye with enough
exposure. The structures in the front of the eye certainly absorb in
this regime; according to the IES Lighting Handbook (8th Edition),
only 2% of radiation at 360nm makes it to the retina. Most is absorbed
by the lens. Which means it probably is degrading the lens to some
extent.

According to them, "The lens shows a number of changes with aging,
including a yellowing coloration, and increasing proportion of
insoluble proteins, sclerosis with loss of accommodation, and
cataract. There is a growing body of evidence, mostly epidemiological,
to implicate ultravioler radiation in these changes." They define UV
as 100-400nm, and list effects on the eye as "Photokeratitis,
cataracts (immediate and long term), coloration, sclerosis, and
retinal changes".

> and i guess what you were
> saying that even though its long wavelength would make you go blind so that
> tells me that a Coolwhite office bulb at 550nm would over time make you go
> blind??

There's a difference between the action of 350nm and 550nm on the
human body.

{snip}
--
-Stephen H. Westin


From: danek danek@ll.mit.edu
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Mon, 23 Jun 2003 

Well, the numbers are based on calculations so they can lead to the absurd when taken to
the extreme. Please note that the numbers I quoted are for 350nm only. The type and
threshold of damage is wavelength dependent so the numbers for 226nm will be different.

The most comprehensive publication I have found so far is Sliney and Wolbarsht's Safety
with Laser and Other Optical Sources. It is out of print now and was originally published
in 1980. While it is old, it is still frequently referenced.

I would be curious myself if more research has been done into UV damage and the eye. I
just found a paper published in 1979 on research done on rhesus monkeys, Zulich's
Cumulative Effects of Near-UV Induced Corneal Damage. The monkeys were exposed to 350nm
light for various periods and also given time to recover. He found that given a dose 41%
below damage threshold over a 24 hour period the eye would fully recover in 48 hours.
Assuming our eyes are the same (a big assumption), UV exposure would not be cumulative over
a lifetime but over a period of several days. According to this paper he was continuing
his research into these effects but I haven't done a literature search to see if anything
more was published.

P. Danek

Chris Carlen wrote:

> danek wrote:
> > Honest to god that is verbatim what is in the IEC standard. For a 10 second exposure
> > it is 10^4 J/m^2 at 350nm and for 1000 seconds it is 10 W/m^2.
> >
> > P. Danek
> >
> > Chris Carlen wrote:
> >
> >
> >>danek wrote:
> >>
> >>>Biological damage is dependent upon three things; wavelength, power density
> >>>(power per unit area) and exposure time. Different parts of the eye absorb and
> >>>transmit different wavelengths. While 350nm light is over 90% absorbed by the
> >>>lens it is almost transparent at 315nm. Given a particular wavelength and
> >>>exposure time a laser could cause damage while a light bulb may not since it
> >>>doesn't have the same power density. Lasers and LEDs are far more dangerous
> >>>than bulbs for precisely this reason. They have a much higher power density.
> >>>
> >>>According to the IEC standard 60825-1, the pathological effects of UVA
> >>>(315-400nm) light are photochemical cataracts, skin burn, pigment darkening and
> >>>photosensitive reactions (i.e. if you are on meds that make you sensitive to
> >>>sunlight). The maximum permissible exposure limit for ocular exposure to laser
> >>>radiation at 350nm is 3x10^10 W/m^2 for <10^-9 seconds. So yes you can damage
> >>>the eye at 350nm but I doubt that a light bulb can put out 300 watts per square
> >>>meter at that wavelength. There is still some debate as to whether long term
> >>>exposure to low doses cause damage to the eye, in the form of cataracts, and
> >>>damage to the skin. The moral to the story is if you are using a source that
> >>>can produce of high power density then you have to do some homework to figure
> >>>out if you need to use filters to prevent bodily harm. You can NOT summarily
> >>>say that a particular wavelength of light is "eye safe".
> >>>
> >>>P. Danek
> >>
> >>What is this: 3x10^10 W/m^2 for <10^-9 seconds ?
> >>
> >>That says to me 30 gigawatts per square meter for less than one nanosecond.
> >>
> >>Is this what you intended?
>
> Ok, let's think about this. The power level indicated, delivered for
> the time indicated would result in a 30J energy deposit. Over 1m^2
> that's 3mJ/cm^2.
>
> Now in my experience, 3-4mJ of UV at a somewhat shorter wavelength in
> the range of 226-285nm delivered in 10ns (a tenth of the power of the
> IEC standard) and with an area of about 0.5cm^2 (twice the energy
> density) is capable of making an audible "clicking" sound on a business
> card. This is the result of ablation of material, and will eventually
> etch the card over time, forming a relief pattern of the beam profile.
>
> Precisely then, my experience is for about twice the energy density but
> one tenth the power density over a .5cm^2 area. It is likely that this
> really is the damage limit, as I am fairly confident that 1.5mJ over
> 0.5cm^2 is at the point where the audible clicking disappears. However,
> this is still a substantial amount of radiation, just under the ablation
> threshold, and will cause bright fluorescence of a phosphor.
>
> I would hardly dare expose my eyes directly to this.
>
> Perhaps this is a safe single shot exposure for the sake of not causing
> acute burns or damage to the eye, but for prolonged exposure to this
> level of power such as from a repetitively pulsed laser, I can't fathom
> how that could be safe.
>
> Regarding the other two figures, the 10^4J/m^2 for 10s exposure would be
> 100mW/cm^2, which is still awfully high. A 100mW laser beam expanded to
> 1cm^2 is extremely bright.
>
> The final figure is the most interesting. At 1mW/cm^2 for the 1000s
> prolonged exposure, this is about the level of power density that would
> be expected from a UV LED, which started this whole thread. It seems to
> indicate that a 350nm or longer wave LED or other UV source of similar
> output could be stared into at such a distance so that the power density
> is <1mW/cm^2 for a rather lengthy period, with the result of a low risk
> of adverse health effects. Note this is not meaning that one could
> stare into a collimated beam, which would focus onto the retina at a
> much higher power density, but that the power density of 1mW/cm^2 may be
> safe for corneal exposure, and to look at if the source is not collimated.
>
> There are many unanswered questions though, such as are these exposures
> cumulative over a lifetime, or is there some ability of the eye to
> repair the acute effects, so that if you get hit every few months for
> instance, the net effect would be no worse than a single exposure?
>
> I doubt this is the case, as I have always believed UV effects to be
> cumulative over a lifetime. But I am analyzing this information to
> learn rather than to judge, so I would be interested in further readings
> about this.
>
> I find the IEC numbers that you've quoted to range from the absurd to
> quite reasonable.
>
> Where might I find this IEC 60825-1 publication? Unfortunately, I tried
> searching for it at iec.org, and got "No items found."
>
> Good day!
> --
> Christopher R. Carlen
> Principal Laser/Optical Technologist
> Sandia National Laboratories CA USA
> crcarle@sandia.gov -- NOTE: Remove "BOGUS" from email address to reply.


From: "Eric Gisin" ericg@go.to
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Mon, 23 Jun 2003 

A case of G8T5 is available to the general public at
www.electriciansupplies.com/index.cfm/S/8/CLID/31/Germicidal_Preheat_Light_Bul
bs.htm

Note the URL was folded.

"Grippin" milo@lightbulbshop.net wrote 
| The bulbs are not available to the general public and not even myself as a
| distributer can buy them
| a 4 watt or g4t5 bulb i sell for 14.49, if i need to be at a better price
| let me know and i'll see what i can do to work the numbers.
...


From: "Grippin" milo@lightbulbshop.net
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Wed, 18 Jun 2003 

well you are using outdated material to research with for starters
according to American Ultraviolet ordinary glass is Opaque to ultraviolet
rays and thus will not let it pass through easily
http://www.americanultraviolet.com/spot_curing/techsheets/index.htm
or go to www.americanultraviolet.com as their main page
...



From: Victor Roberts Vic@RobertsResearchInc.com
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Wed, 18 Jun 2003

"Grippin" milo@lightbulbshop.net wrote:
>well you are using outdated material to research with for starters

Outdated material  {LOL} I don't think the properties of 0080 glass
have changed in any significant manner since 1984, or even for many
more years than that. Perhaps you also think that the value of PI or
the density of water or the speed of light cannot be obtained from a
reference book published in 1984. And, the Schott data is certainly
current. Here is some additional data on normal soda lime glass:

http://www.valleydesign.com/soda-limepic.htm

As you can see, the transmission of soda lime glass according to this
source remains high down to 350 nm.

>according to American Ultraviolet ordinary glass is Opaque to ultraviolet
>rays and thus will not let it pass through easily
>http://www.americanultraviolet.com/spot_curing/techsheets/index.htm
>or go to www.americanultraviolet.com as their main page

The site you reference states "Ordinary glass is opaque to SHORTWAVE
GERMICIDAL ULTRAVIOLET. (The emphasis is mine.) The same site defines
germicidal ultraviolet as radiation between 200 nm and 300 nm.

When discussing UV light, you need to be careful to define the
wavelength you are talking about. UV covers a broad enough range of
wavelengths that the response of materials, including human organs,
can vary quite a bit over the so-called "UV range". 
--
Vic Roberts
http://www.RobertsResearchInc.com


From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Wed, 18 Jun 2003 

Grippin wrote:
>UV emited from either Flourescent or LED will only pass through quartz
>glass and will not pass through windows or eyewear. the only uv that will
>pass through glass such as windows, eyewear is that of a 400 to 450 nm
>range

Most "ordinary glass" is transparent to largely transparent down to
about 350, maybe 340 nm.

It has close to no blocking of 360 nm blacklights nor of the output any
UV LED of peak wavelength as low as 370 nm. "Ordinary glass" even passes
most of the output of 350BL blacklights that have a peak wavelength of 350
nm.

- Don Klipstein (don@misty.com)


From: Victor Roberts Vic@RobertsResearchInc.com
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Wed, 18 Jun 2003 

"Grippin" milo@lightbulbshop.net wrote:
>UV emited from either Flourescent or LED will only pass through quartz glass
>and will not pass through windows or eyewear. the only uv that will pass
>through glass such as windows, eyewear is that of a 400 to 450 nm range

Fluorescent lamps, incandescent lamps and windows are typically made
from soda lime glass such as Corning 0080. I don't know what glass is
used for eye glasses. Many glasses will pass radiation below 400nm.
The Glass Engineering Handbook, Third Edition, George W. McLellan and
Errol B. Shand, McGraw-Hill Book Company, 1984 has transmission curves
for a number of glasses. Unfortunately I only have copies of the pages
dealing with UV-transmitting glasses, such as Figure 16-1.

The CRC Handbook of Physics and Chemistry, 51st Edition states that a
1 cm thick piece of "ordinary Crown glass" has a transmission of .974
at 375nm. I must admit I am not sure what is meant by "ordinary crown
glass" but I suspect it is soda lime glass.

Schott has a transmission curve for their "Super White Soda-Lime
Glass" on their web site at:

http://www.schott.com/whitegoods/english/products/borofloat/attribute/optical/images/borosilicate_crown_glass.pdf

You will see that this glass, which may not be the same as 0080 soda
lime glass, has 50% transmission at 325 nm.
--
Vic Roberts
http://www.RobertsResearchInc.com


From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Sun, 22 Jun 2003 

Clive Mitchell wrote:
>Don Klipstein don@manx.misty.com writes
>>I have yet to hear of any of these being called a "blacklight white" even
>>though the dark colored ones are called "blacklight blue".
>
>It's strange. The ones they call blacklight are bright blue, and the
>ones they call blacklight blue are pretty much black. :)
>-- Clive Mitchell http://www.bigclive.com

Blacklight blue (BLB) is dim deep violet-blue and when unlit are
violet-bluish black, while BL (peak wavelength 360 nm) is a brighter light
blue and when unlit are white (like every non-filtered fluorescent bulb,
including UVB medicinal types, UVA suntanning types, actinic types, and
totalling at least three different UVA ones).

I was commenting on this Grippin guy saying something was called a
"blacklight white". Never heard of anything called a "blacklight white"
before this thread.

- Don Klipstein (don@misty.com)


From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.engr.lighting,sci.optics,sci.electronics.design,sci.astro.ccd-imaging
Subject: Re: UV Safety Satandard
Date: Sat, 21 Jun 2003 

Grippin wrote:
>if it is a "white" tube and uv it is going to be 350nm or Blacklight White

Who makes anything called a "blacklight white"?

UV-producing fluorescent lamps that appear white when off could be any
number of things: Plain BL (360 nm), 350BL often used for bug zappers
(350 nm), tanning lamps (?? - 325 nm - anyone know here??), and UVB lamps
(310 nm?). Also one of the actinic lamps produces UV, and another (03)
produces mostly visible violet (peaking at 410, maybe 415 nm) and in many
ways seems like a blacklight.

I have yet to hear of any of these being called a "blacklight white" even
though the dark colored ones are called "blacklight blue".

- Don Klipstein (don@misty.com)



From nikon MF mailing list:
Date: Sun, 26 Oct 2003 
To: nikon@photo.cis.to
From: Francis Corvin francis_@gmx.net
Subject: Re: [Nikon] advice concerning sources for filters
Reply-To: nikon@photo.cis.to

 May, Eugene wrote:
>After considerable time (!) spent
>searching, I finally got a 105 mm F/4.5 "UV Nikkor". I would like to use it
>with UV filters with fairly narrow bandbasses in the 200 - 400 nm range, and
>would like recommendations concerning manufacturers that would make these in
>single-unit quantities.

Have you checked Bjorn Rorslett site? He has a page on UV filters.
http://www.naturfotograf.com/UV_IR_rev04.html#top_page
I don't think all the information you want is there but there would be no
harm in contacting him I guess.

Regards,

Francis


From: hansen@src.wisc.edu (Roger W. C. Hansen) 
Newsgroups: sci.optics 
Subject: Re: UV Light detector 
Date: Thu, 4 Sep 03 

"Roland Burton"  rwburton@interchange.ubc.ca wrote: 
>Hello Group 
> 
>I'm building something which needs good response to light around 340-360 
>(um?). So I went to the local electronics shoppe and bought the only 
>photodiode in the shop and it turns out to respond to IR and a little bit to 
>visible, not to UV at all. Looking at electronics catalogs doesn't get me 
>much. Can someone recommend to me a good UV 
>diode/transistor/darlington/schmitt? Need to switch/sense at around 100 
>khz. 

Hamamatsu Type S1226-8BQ and G1127-02 are responsive in the 
UV and I have used them. Unfortunately the factory installed 
windows do not tranmit UV and must be removed. Their response is 
documented in SPIE Proceedings 733, (1986) 481-485. 


From: Pieter Kuiper Pieter.Kuiper@msi.vxu.sweden 
Newsgroups: sci.optics 
Subject: Re: UV Light detector 
Date: Thu, 04 Sep 2003 

 
jpopelish@rica.net (John Popelish) wrote: 
> Following up on my earliersuggestion about using LEDs as detectors: 
> 
> I lined up a bunch of different color LEDs in a row, and measured the 
> voltage out of various color LEDs used as a detector for the light 
> from each, and the result verified my earlier comment. Any LED I 
> tried had some to little output when illuminated with a similar LED, 
> very low output if illuminated with any longer wavelength than it 
> emits, and strong output for shorter wavelengths than it emits. 
The output is maximum for photon energies very close to the band gap of 
the material. Longer wavelengths cannot produce electron-hole pairs. 
For shorter wavelengths the yield is lower than near threshold. 
Probably, the absorption is so strong that the light does not reach the 
junction. 
Of course, the geometry of LEDS is not optimized for use as detectors... 
> The shorter wavelength emitters prouce more open circuit voltage than 
> longer wavelength emitters. If you want a detector that is nearly 
> blind to the visible spectrum and longer wavelengths, use a blue or 
> near UV LED as detector (370 to 430 nM, say). Any package that is 
> designed to work at 400 nM will probably be pretty transparent to 340 
> nM as well. 
The semiconductor is not transparent at shorter wavelengths. 
(Unless the light is emitted by recombination centers, like the red LEDs 
that use the same semiconuctor with the same forward voltage as the 
green ones.) 
-- 
Pieter.Kuiper@msi.vxu.se http://www.masda.vxu.se/~pku/ 	 



From: jpopelish@rica.net (John Popelish) 
Newsgroups: sci.optics 
Subject: Re: UV Light detector 
Date: 4 Sep 2003 

...
 
Following up on my earliersuggestion about using LEDs as detectors: 
I lined up a bunch of different color LEDs in a row, and measured the 
voltage out of various color LEDs used as a detector for the light 
from each, and the result verified my earlier comment. Any LED I 
tried had some to little output when illuminated with a similar LED, 
very low output if illuminated with any longer wavelength than it 
emits, and strong output for shorter wavelengths than it emits. The 
biggest range I tested was using an 850 nM emitter to detect light 
from a 400 Nm emitter. 
The shorter wavelength emitters prouce more open circuit voltage than 
longer wavelength emitters. If you want a detector that is nearly 
blind to the visible spectrum and longer wavelengths, use a blue or 
near UV LED as detector (370 to 430 nM, say). Any package that is 
designed to work at 400 nM will probably be pretty transparent to 340 
nM as well. 	 



From: "Harvey" xh.ruttx@ecs.soton.ac.uk
Newsgroups: sci.optics 
Subject: Re: UV Light detector 
Date: Thu, 4 Sep 2003 

Hamamatsu sell a GaP detector which being wide band gap could be a good 
choice, or at least they did a while back. 

Also there has been some availability of doped diamond based detectors, 
visible blind, for use in flame detectors I think. I dont recall the 
company, it *might* have been Centronic in the UK? Not sure of the spectral 
resonse. 

Si detectors can be bought 'blue/UV enhanced' (coatings to improved coupling 
& junction optimised for shallow penetration) from some firms, but of course 
you cannot beat the responsivity varies at least as badly as lambda limit. 
But flame detectors for bioilers etc are a place to look, UV is used I think 
because only the *flame* emits UV & if it goes out the UV gives a flame 
failure warnning, (& you turn the fuel off.............) whereas IR is 
blinded by the hot furnace etc wall. 

Harvey 


From: muth@unity.ncsu.edu (John Franklyn Muth)
Newsgroups: sci.optics
Subject: Re: Ultraviolet LED Availability
Date: Thu, 18 Dec 2003 

In university research lab LEDs as short as 275 nm have been made with
very low output powers. Sandia is one of the leaders in this technology.
If you search for SUVOS on the DARPA websight you can find more
information.

phil harris (phil.harris@ametek.com) wrote:
: I have been reading about some interesting research at Sandia, where
: they are working on and have produced light emitting diodes at 325 ,
: 300 and 285 nanometers. Anybody know of these being available
: commercially, even at very low powers ? Any idea when such devices may
: become available commercially ?



From: rob_mueller@dofasco.ca (Rob Mueller) 
Newsgroups: sci.optics 
Subject: Re: UV Light detector 
Date: 10 Sep 2003 

"Roland Burton" rwburton@interchange.ubc.ca wrote 
> Hello Group 
> 
> I'm building something which needs good response to light around 340-360 
> (um?). So I went to the local electronics shoppe and bought the only 
> photodiode in the shop and it turns out to respond to IR and a little bit to 
> visible, not to UV at all. Looking at electronics catalogs doesn't get me 
> much. Can someone recommend to me a good UV 
> diode/transistor/darlington/schmitt? Need to switch/sense at around 100 
> khz. 
> 
> Thanks in advance 
> 
> Roland Burton, Mass Spectrometrist. 

Try looking at the UV photodiodes from Boston Electronics: 
http://www.boselec.com/products/detmain.shtml 

Consider the SiC or GaN devices. 

Rob



From: brianc1959@aol.com (brian) 
Newsgroups: rec.photo.equipment.large-format 
Subject: Re: Diffraction again - frequency 
Date: 18 Sep 2003

john@stafford.net (J Stafford) wrote 
> 
> I claimed nothing. I posed a query to Net Wisdom, and it is clear from the 
> excellent responses that some experiments are warranted. And I wrote that 
> I was using a deep green filter because green gave me the colors that 
> worked best with the subject. However, shooting toward the blue/uv 
> frequency range seems promising for another subject. 
> 
> But at this point I'm busy enough with the Day Job, and have found the 
> F180 aperture on the wide 5x4 to be a Bad Thing so it is back to F8 and 
> modest filtration - business as usual. 
> 
> An aside - to the Net - shooting into the UV requires a UV ('quartz') lens 
> (and extended UV film of course). No? I've only seen one such lens in my 
> life - the one made for the Hasselblad, and apparently they have become 
> outrageously expensive. 

Shooting toward the blue/UV will definitely help sharpness at f/180. 
The optical correction will be fine (still *very* 
diffraction-limited!), but transmission losses might start to be a 
problem. Even with a high-transmission UV lens the exposure time will 
be extremely long because of limited illumination. Special UV lenses 
aren't strictly required for UV shooting, but they do help. I 
recently tested a new 105mm fluorite/quartz objective against a 
conventional 105mm micro-Nikkor, and found that the conventional glass 
did transmit a small amount of UV. 

Brian 
www.caldwellphotographic.com


[Ed. note: some points on the upper range where UV turns into x-rays ;-) ]
Date: Thu, 05 Feb 2004 
From: "Mark W. Lund, PhD" mlund@powerstream.com
Newsgroups: alt.sci.physics,sci.med.physics,sci.astro,sci.optics,sci.research
Subject: Re: A question, why can't X-rays be focused and visible light can?

Actually, x-rays can be focussed, it is just hard. Since I used to be
an expert in this area, I'm glad you asked.

1. Grazing incidence optics. If the x-rays are incident on a
surface near grazing you can get reflectivity for quite high energies.
The Chandra x-ray space telescope uses this effect.

2. Artificial crystals. For low energy x-rays you can build a normal
incidence multilayer mirror that works quite well. There have been a
number of telescopes built to look at the sun using this method. Anyone
who hasn't seen the November issue of the Review of Scientific
Instruments should look it up. There are some stunning pictures
of the sun, including a high resolution image that is mind-blowing.

3. Since the index of refraction of all materials is very slightly
less than one in the x-ray region a biconcave lens is is a positive
lens. This is exciting because you can make a biconcave lens very
thin at the center. I wrote a paper on this topic in the Journal
of X-ray Science and Technology a few years ago. If you line up
a bunch of these lenses you can get focal lengths of 1 meter fairly
quickly. Of course such a lens has very little field of view.

4. Bringing us to the topic of medical imaging. There are
x-ray microscopes that can image cell-sized things, but even though
it is theoretically possible to image chest x-rays it is not practical
at this time. So they use shadowgrams.

Best regards
mark

John Leonard wrote:
> I have read that no way has been found yet by which X-Rays can be
> focused. Is there any medical application for the ability to focus X-rays? I
> am scientifically challenged and so I would like to ask for a reasonably
> easy to understand explanation of why visible light can be focused but
> X-rays cannot.
>
> Thank You,
> John Leonard
>
> Crossposted to:
> alt.sci.physics;sci.med.physics;sci.astro;sci.optics;sci.research

Mark W. Lund, PhD 
CEO  PowerStream Technology 



From: brianc1959@aol.com (brian)
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: ultra-super UV apochromatic? Re: Zoom vs. fixed focal length
Date: 11 Nov 2003 

rmonagha@engr.smu.edu (Bob Monaghan) wrote 
> . . . . many of the UV (quartz) lenses may
> provide great correction from shortwave UV to IR

Just a note on this: quartz alone makes a very poor wideband lens,
and is in fact used in the high dispersion "flint" elements in UV-VIS
hyperspectral apochromats. There have been some all-silica lenses
built for deep UV photolithography, but these were intended for
narrow-band laser illumination. Also, if you extend correction down
to the deep UV (~ 250nm) then in my experience you can't get longwave
correction beyond about 650nm (red). Coastal Optical currently makes
a lens of this type: http://www.coastalopt.com/stan_02.asp Moderate
UV to IR apochromatic correction is possible, however (350nm -
2000nm).

Brian
www.caldwellphotographic.com


From: "Vijay Kumar" me@privacy.net
Newsgroups: rec.photo.misc,rec.crafts.misc
Subject: Re: Source of UV glass
Date: Thu, 30 Oct 2003 

"Geoffrey W. Schultz" schultzAT@ultranet.com wrote...
> I do a lot of framing and have typically used window glass. For some of
> the work I'd like to use UV glass or optically clear (non-green) glass, but
> I can't find any source for the glass other than framing shops. Does
> anyone have sources for the type of glass that will ship it via UPS or
> FedEx?
>
> Thanks, Geoff

Try www.lightimpressionsdirect.com . They stock a variety of UV resistant
material. They are a definitive source of all archival materials. Many
galleries use their materials. May not be exactly cheap. But get the
catalog as it is quite educational.

No personal connections other than being a satisfied customer.



From: don.janeczko@itt.com (DonJan)
Newsgroups: sci.optics
Subject: Re: Optical silica
Date: 8 Mar 2004 

hbarwood@troyst.edu (Henry Barwood) wrote
> Does anyone know a source for some large pieces of optical silica? It
> could be fused quartz, synthetic quartz, or? I need pieces at least
> 2.5 X 2.5 X 15 cm in size for an experiment. Price must be low as I'm
> doing this on my own. Thanks.
>
> Henry Barwood
> hbarwood@troyst.edu

Try www.bscoptics.com or get a dmaged quatz optical flat.



From: don@manx.misty.com (Don Klipstein)
Newsgroups: sci.optics
Subject: Re: Black Light - Ionizing Radiation?
Date: Sun, 18 Jan 2004 

Curious wrote:
>Is black light ionizing radiation?

"Black light" usualy refers to the longer and middle wavelengths of
the UVA portion of the ultraviolet spectrum (and not the suntanning
shorter wavelengths of UVA, even though they also have some "blacklight"
effects).

UVA is the longest-wavelength "segment" of the ultraviolet spectrum, the
"region" closest to visible. Longer wavelengths of the "blacklight" range
are slightly visible.

By the most common definition, 315-400 nm is UVA. 380-400 nm is
arguably visible, and wavelengths as short as 345-350 nm are to some
extremely slight extent visible in conditions favoring their visibility.
Suntanning is generally from wavelenbths shorter than 340 nm.

Then there is UVB, which has a fair amount of "blacklight" effect and is
much more harsh on living things than UVA is.
By the most common definition, UVB is 280-315 nm. There is an
alternative definition of 286-320 nm for UVB.

UVA and UVB are widely considered to not be "ionizing radiation".

The next segment of the ultraviolet spectrum (by progressing into
shorter wavelengths) is UVC. The longer wavelengths of the UVC range are
the wavelengths that are worst for living cells, and an easily-generated
mercury wavelength of 253.7 nm (blocked by ordinary glass and most other
transparent substances other than more expensive ones selected for special
ability to pass this shortwave UV wavelength.) The wavelength hardest on
living cells is close to 260 nm.
Many people subdivide the UVC range into "vacuum ultraviolet" (near and
shorter than 200 nm, by-and-large absorbed by a few feet or a meter or two
of air and by most other transparent substances) and the "non-vacuum-UV"
portion of UVC. (A 1 millimeter thick layer of pure quartz is close to
50% absorbing at 180 nanometers, and is even somewhat absorbing of
mercury's ozone-producing wavelength of 184.9 nm.)
I have noticed 253.7 nm but not 184.9 nm causing blue-fluorescing white
cotton clothes to fluoresce (I have a few first-surface aluminum-surface
diffraction gratings). 253.7 nm is a popular wavelength for
geologists/mineralogists to cause rocks/minerals to fluoresce, while
longer UV wavelengths (especially not far from 360-366 nm) are generally
favored for causing organic compounds to fluoresce.

"Ionizing radiation" wavelengths of ultraviolet are generally
near/shorter-than 200 nm.

I would say that "ionizing" and "blacklight" wavelengths of ultraviolet
are to some extent "mutually-exclusive" more than "overlapping", although
this is not a "black-and-white" case. However, the UV emissions of the
usual "blacklight" lamps in a disco are not "ionizing radiation" except to
more exotic materials such as the vapors of a minority of metals.

- Don Klipstein (don@misty.com)


From: Andrew Resnick andy.resnick@.grc.nasaDOTgov
Newsgroups: sci.optics
Subject: Re: Refractive index of quartz glass
Date: 1 Apr 2004

 
Rene wrote:
> Hi
>
> I'm looking for a list with refractive index of quartz glass at aprox.
> 30oCelsius and with different wavelength from 200nm up to 400nm. Does
> anyone have a idee where to find this ?
>
> Thanks for the help.

Try:

http://www.luxpop.com/

They have quartz and fused silica. Presumably you mean fused silica, as
crystalline quartz is birefringent. In any case, it's a good database
to have on hand.
--
Andrew Resnick, Ph. D.
National Center for Microgravity Research
NASA Glenn Research Center	 



From: "Johannes Swartling" johannes.swartling@home.se
Newsgroups: sci.optics
Subject: Re: UV questions
Date: Wed, 14 Jan 2004 

"jon" j-spangler_NO_@raytheon_SPAM_.com wrote 
>
> As long as I'm passing on "what I've heard", I've been told that "cheap"
> sunglasses (depending on the material) may be worse for the eyes since they
> could pass UV energy unattenuated while reducing the visible energy which
> causes the eye's pupils to open more, allowing even more UV energy in. (Or
> was that on old wive's tale?)

There was a test published in a Swedish newspaper a few years ago where they
had let some lab test a large number of sunglasses ranging from cheap to
expensive. The conclusion was that all of them were very effective UV
blockers and that there was no difference between cheap or expensive.

Johannes



From: Helmut Wabnig "jon"

>
>As long as I'm passing on "what I've heard", I've been told that "cheap"
>sunglasses (depending on the material) may be worse for the eyes since they
>could pass UV energy unattenuated while reducing the visible energy which
>causes the eye's pupils to open more, allowing even more UV energy in. (Or
>was that on old wive's tale?)

we did actual measurements on about 20 different sun glasses,
and the "cheap" glasses were the best UV blockers.
Guess that the money goes into STYLING, not performance.


w.
hXXXwabnig@aXXXon.at
Newsgroups: sci.optics
Subject: Re: UV questions
Date: Tue, 13 Jan 2004 


From: Brian Sweeney [brianvsweeney@comcast.net] 
Sent: Thu 10/23/2003 
To: Lenses@topica.com 
Subject: [LENSES] Pentax Ultra-Achromat

Does anyone on the list know anything about the Pentax 85mm F4.5 Ultra
Achromat? It is in standard 42mm screw mount with an automatic aperture. It
is on an OLD streak camera in the lab. It is interesting, and I have never
read about it before. A quick google search did not reveal anything.

Brian



From: gr greif1nospam@rochester.rr.com
Newsgroups: sci.optics
Subject: High resolution Nikkor Lenses
Date: Wed, 30 Jun 2004 

Original post asked: (which expired on the RR server)
I'm looking to purchase, borrow or rent a 95mm Printing Nikkor lens
(Product Number 95190). If anyone has one let me know.

Second, I'm interested in the performance of the UV-Micro Nikkors,
especially the 105mm f/4.5 (Product Number 1453). I know that it has
excellent transmission from 220nm to 900nm but I don't know what the
resolution, MTF etc. is in those bands. I suspect that it is corrected
for monochromatic aberrations but not polychromatic. That it probably
must be used with a filter and focused for every wavelength. I
requested the information from Nikon but have not received an answer.

----------------
Reply:
1) I used the printing Nikkor in the past in a microfilm reformatting
system; very nice performance!

2) I dug up some old Nikon lit and actually found a sheet on the
UV-Nikkor; specs are; (sept 1985 new product sheet)
May 1986 dealer price list says List $2200.00 and Dealer cost $1430.00

FL: 105mm
aper f/4.5
Construction; 6 elements in 6 groups
Picture angle; 23 deg 20 min
Aperture scale; f 4.5 to f 32
Exposure measurement; via full aperture, coupling ridge for Al, meter
coupling for non Al
Distance scale : 0.48m to infin
weight; 525g
dimen; 68.5 diam x 108mm long 116.5 overall
filter; 52mm
lens hood; built in telescopic
teleconverter; TC-14A or TC201

Text blurb states:
UV to IR 220um to 900
Apo lens design up to 220um
1:2 lifesize possible, 2:1 with PN-11






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