Index:
Cutting Filter-Costs with Adapters
Filter Price Markups - Yikes!
Leica Photographers on Using Filters (Jim Brick)
Homemade Filters
Multicoating Myths
Protective Filters - To Use or Not to Use
Resolution Tests of Filters
Series Filter Sizes
Solar Eclipse Filter Safety (and sources)
Tricolor Filter Effects (Harris Shutter)
Ultraviolet Filters Vary in UV Absorbed (Tiffen..)
Postings related to Filters

Related Sites:
81A filter notes
About circular vs. linear polarizers (W.J. Markerink)
About Polarizers (W.J. Markerink)
All About Filters (Ken Rockwell) [9/2002]
B&W; Filters [3/2002]
Bob Shell's Lens Hoods and Filters - The Basics (beststuff.com) [5/2001]
Choosing a Filter (light measurement hbk)
Color Filters (W.J. Markerink)
Cokin Filters User Page [1/2001]
Cokin X-pro 170mm x 130mm filters [3/19/99]
CRC Filters Reference Info
Filter FAQ
Filters (Photo.net)
Filters Article (Chris Bitmead)
Filters Article (Nelson Tan)
Filter Connection (links to filter mfgers online)
Filter Factor Table
Filter Facts for Nature Photography by Ken Wyatt
Filter List (w. prices)
Filter Q and A
Filter Related Links by Ronald Shu
Filter Shop Closes (posting) [8/2002]
Free Filters Tip! from Jim Franz
French Cokin Filter Gallery Site [7/2001]
Gradual Filters, which ones work best?
Kodak on Filters
Homebrew Infrared Filters
Homemade Infrared #87 filter equiv. using E-6 Film
Hoya Filters site (kenko/tokina)
Hoya multicoated vs coated page [07/2000]
Infrared Filter Data
Medium Format Digest Posts on Filters
Multi-Coating, Why it is worth the extra cost?
Neutral Density Filters (added 10/99)
Observing Eclipses Safely
Photo Filters FAQ
Polarizers and UV filters
Schneider Optics Filters for Still Photography Pages [4/2002]
Soft Focus Filters, which one is the best?
Solar Filter Tips
Swedes nix Cokin filters MTF..
Using Filters for Non-Traditional Light Sources
UV and Polarizer Filter FAQ
Warming Filters, are they all the same?
When NOT to use a UV Filter
Which Filters Do What?
Wide and Wonderful World of Filters
Wratten Filters
Wratten Filter Numbers

Introduction

I have dozens of filters. But I really mostly use just a polarizer and warming filter (Tiffen #812 or #81A or #81b) for color work. We all have filters we haven't used in years collecting dust. Be sure you really need those odd-ball filters before you buy them.

Why do so many camera store clerks push the use of a "protective filter"? The answer is that filters have the highest markups, which is to say the most profits, of anything they can sell you. Those $15 and $20 filters cost the store circa $1 (see below). The lens protection you need is usually supplied free by the manufacturers in the form of front and rear lens caps.

Good filters degrade image resolution by approximately 2%. A cheapy non-flat bad filter might degrade the image quality by 10%. A thumbprint on your filter can reduce contrast by 20%+. I don't like protective filters because they accumulate scratches, thumbprints, and dirt which add flare and reduce contrast in your photos. Look in the used filter bargain box at most camera dealers or camera shows to see lots of evidence of scratched and dirty "protective filters" in recent use.

Filters can be alarmingly expensive for the highest priced brands. The most costly filters are very flat, with non-binding brass rings and multicoatings. Fortunately, tests of filters have repeatedly shown that the results are indistinguishable on film between the good (e.g., Hoya) and the most expensive filters. So putting a $150 filter on a $2,000 lens, let alone on a $150 zoom, is overkill. You most likely couldn't tell the difference on film against a $15-$20 Hoya or Tiffen filter or other decent quality brand. Spend the money on film instead.

I prefer single coated filters over multicoated, which are often harder to keep clean. There are lots of reasons to believe that multicoated filters don't significantly improve image contrast and quality over coated filters. The light that bounces off the surface of the filter, which is carefully setup to look impressive in some ads, wouldn't be going through the lens or end up on film anyway. Reducing reflections circa 3-5% with multicoating on the inner filter glass surface isn't likely to reduce contrast by a noticeable amount over a singly coated filter. You will get much more contrast improvements by investing in a flare reducing lens hood.

An exception where multi-coated filters might be useful is in night photography with very high contrasts between lights and black shadows. An even better approach is to avoid using filters in these situations and use filtering at the printing stage. I have lots of uncoated glass filters which also work well. These older filters aren't worth replacing with coated filters for the amount of times I use them. Keep direct light or sunlight from hitting the uncoated filters, and they'll probably work just fine for you too.

We will look into some low cost specialty filters you can make very cheaply below. If you are going to use a lot of filters or turn semi-pro, you should look into the use of stepping rings. You can use a 77mm filter on a 67mm or 72mm filter sized zoom or prime lens using the right adapter ring, saving the costs of buying multiple filters of the same type.

The "organic glass" or resin (i.e., plastic) 3x3" and larger filters such as those by Cokin can be useful. The quality is usually acceptable, especially for medium format and LF users. The majority of filters are so specialized you would be lucky to use them a few times a year in general shooting. I find the graduated neutral density filters are handy for balancing light levels in landscape photography, as one example. But see the postings below on issues like color casts of some "neutral grey" Cokin filters and options for glass based ND filters that work in other holders for pro use.

Many of the postings below relate to specific problems, such as the search for a thin filter for use on wide angle lenses or alternatives to specialty filters for Hasselblad 93mm bayonet mount lenses. We also have material on older filter bayonet mounts for TLRs, tables of light conversion filters, and tips on solutions to various filter related problems. Enjoy!

Filter Price Markups - Yikes!
Photographic filters are the highest markup items in most photography stores:

In other words, the $15 to $25+ you spend on a name brand filter is probably ten to twenty times what the filter cost the store. It gets worse, since I am told the cheapy no-name filters you buy for $10 or less cost under a quarter ($.25US) each! As we will ask below, how much optical precision and quality do you expect to get for under a buck? Or for a quarter? [see notes for price updates].

My point here is that camera stores and the photo-industry have a vested interest in promoting sales of photographic filters. In many cases, the store or discounter may make more profits from selling you the filter than the lens it goes on. Authors of photobooks rely on store sales and promotion, so they don't want to challenge ''conventional wisdom''. Photographic magazines are filled with camera store ads too. So providing an alternative view and detailed understanding is one goal of this online article.

Protective Filters

Actually, my questions to some top professional photographers suggest that some of them use protective UV filter usage as an indicator of amateur photographer status. Many professionals don't use filters unless they need and want the filter's effects in their photographs. Their ultimate version of lens protection is called professional insurance!

Haze Filters
Haze filters used to cut haze, when we were using older Kodak color films with ASA ratings around 10 with older lenses using balsam based adhesives. Today's lenses have UV absorbing glues so they don't need either UV or haze filters to filter out the UV. Today's films don't need haze filters to offset their UV and blue response either. So why use them, given they don't reduce UV or cut through haze?

Lens Caps
If you really want lens protection, then a good lens cap is what you need. The screw-in kind won't pop-off. Metal and plastic lens caps are better protection than a thin glass filter in most collisions. Since filters are also expensive, shouldn't they also be protected from scratches? Won't scratches on your filters also affect your photography too? So if you seek lens protection, then a lens cap is the logical and obvious way to get it.

Metal Lens Hoods
Related forms of protection include lens hoods, especially the metal kind. As with the metal lens caps, a metal lens hood can provide a lot of protection from many sources of potential harm. There is also no debate at all among professionals about the benefits from using the proper lens hood on your lens. Lens hoods provide real protection from side-light which can induce flare and other defects in your photographs.

By proper lens hood, I mean one that won't vignette the corners of your images by being too small. A lens hood can also be too big, and let in too much side lighting. For fixed focal length lenses, the lens hood choice is usually well defined for a given lens or focal length. For zooms, you usually have to compromise, as usual, on something that works best at the wide-angle end while providing some protection at the other extreme.

An optimal solution can be found in the rather bulky compendium lens hoods, which are bellows-like and easily extended to the ideal protective length. Unfortunately, I have found these to be difficult to use in the field and when frequently switching lenses.

One of the problems with using metal lens hoods is that they rarely fold conveniently out of the way. The major exception is the built-in lens hoods on many telephoto lenses. Some metal lens hoods can be dismounted and remounted "backwards" over the lens when not in use, making them easier to pack. Bayonet mounts are used on some of the medium format lenses and mounts, usually on more professionally priced equipment (e.g., Hasselblads).

You can easily make low cost lens hoods which will cut flare and keep your fingers off the lens, as well as provide some protection in falls and collisions. That's good, because some manufacturers charge up to $900 for their official lens hoods. You might be surprised at how many lens hoods and lens caps you can find at the local grocery store (e.g., Pringles chip caps). And those cold beverage holders of foam rubber given away as promo items make great lens protectors for free too!

Converting Filter Threads to Bayonet Mounts
I found a convenient way to mount and dismount not only filters but also metal lens hoods. Kalt made a series of quick change rings for 35mm lens filter threads. For $15, you could convert a slow filter thread mount into a faster bayonet mount, with an adapter ring for one filter or lens hood. For $5 per adapter ring, you can add filters and lens hoods to this system. I like it. Unfortunately, these adapters are now out of stock and not made anymore. Darn!

HP Marketing and others also sell conversion kits for the Rolleiflex SL-series cameras and others. These professional medium format lens sized adapters make it fast and easy to mount filters and hoods onto and off of your lenses with just a fast twist. As you might expect, the costs are higher too. Top-of-the-line third party brands like Heliopan and B+W also offer bayonet adapter options in the larger filter sizes.

The original Rolleiflex TLR and early Hasselblads (500c) have long offered these convenient bayonet mounted filters and lens hoods options. As a further example, the Hasselblad 500c and progeny have two lens bayonet mounts, one inner mount for filters (e.g., B50) and the other outer mount for the lens hood. This simple approach makes it easy and fast to change filters without impacting the use of the metal lens hood. After you try this system out, you will see why I have searched for a similar approach I could afford for my frequently used 35mm filters (e.g., polarizer).

If you elect to use the amateur or professional slip-on filter systems such as the Cokin/Minolta or similar brands, you have to mount a treaded mounting ring in each lens before use. Now you can slide the Cokin filter holder onto and off of your lenses in a flash. Cokin also makes a set of add-on lens shading elements which you can stack to a modest depth. One handy trick for very wide angle lens users is to trim off all but one of the filter holder slots (usually there are three slots). This trick keeps the filter holder from vignetting the wide angle lens images, an otherwise common problem.

The pro compendium systems with extending bellows style lens hoods do have filter holder slots. These slots are usually only for the more expensive professional brands and styles of filters (e.g., 100mm square filters, vs 82mm ''P'' Cokin or 67 mm ''A'' sized Cokin filters). You can also use gel filters with a cardboard holder. Sadly, the costs of these gel filters have gone up and they are more subject to scratches and moisture damage.

Rubber Lens Hoods
Rubber lens hoods are convenient and cheap, but many photographers believe they provide less collision protection. You already know that the rubber lens hoods also rot and tear easier than the metal ones.

UV Filter Protection Uses
However, there are times when I think a clear UV filter makes sense in protective mode. You may be outdoors, or in a potentially sandy or muddy-spray environment. If so, then using a UV filter for lens protection makes sense to me too. Some types of closeup photography increase your risk of colliding with the subject, again possibly justifying a protective filter use. If you have a fetish for cleaning your optics, then it is probably better for you to scratch up your filter than your lens, at least as far as resale value goes.

Why Not to use a Protective Filter
The argument against using a protective filter is very simple. If you aren't using a top-quality lens filter, you risk reducing contrast and causing other defects on your photographs and slides. The theory is that every air-glass interface scatters light and can potentially reduce contrast. Filters also offer two surfaces to pickup contrast reducing dust and fingerprints and other contamination.

Lenses are designed to be used as-is, without adjustments for filter use. Manufacturers give you a broad hint by providing a lens cap with their lenses, but not a protective filter.

Inexpensive Filter Faults
You already know from the lead posting above that even the manufacturer's filters cost only a dollar or so. The off-brands may cost much less, perhaps a quarter to make. Just how much optical quality do you think you can buy for a quarter? Granted, you and I may have to pay $15 for a twenty-five cent filter, but that over-charge doesn't improve the filter, does it?

These inexpensive filters suffer from a number of faults. It is very costly and hard to get truly parallel and exact thickness to the glass. Most filters are not colored glass, but rather a sandwich of filter gel or colored resin between two pieces of glass. Failure to adequately seal the filter rim can enable moisture to attack the gel, altering the filter characteristics. Another eye opener is to compare identical filter type coloration, not only between brands but even batches. Filters may also shift coloration over time and with exposure to sunlight.

Another sensitive issue is that many pricey manufacturer's filters aren't made by the camera manufacturer at all. Just their name goes on it. They actually get another optical house to make their filters. For example, my Zenza Bronica 67mm UV filter was made by Asahi Optical Inc. (Pentax). Surprise!

Why Expensive Filters are Really Expensive
Only the best filters are truly plano-parallel, with exactly parallel precision ground glass surfaces of identical thickness throughout the filter. This kind of optical precision costs a lot, and so do these filters.

The best filters in my opinion are solid glass which has been batch dyed, although some resin filter designs are also good. My favorites are the Kodak glass series filters in the larger series VIII and IX sizes. These older filters are very high quality, but since series filters are out of favor, the costs are very reasonable.

Some of the original manufacturer made filters have excellent reputations (e.g., Nikon, Canon, Rollei, Hasselblad). A few third parties such as B+W and Heliopan also have excellent reputations among professionals too. The lower-priced filters with brands such as Tiffen and Hoya also have decent reputations. At the low end, the relabeled and no-name filters have optical qualities that reflect their low manufacturing costs (under a dollar, remember?). You generally get what you pay for!

Series Filter	Filter Adapter Range
Series 5	28-36mm filter threads
Series 6	31-47mm filter threads
Series 7	44-56mm filter threads
Series 8	51-69mm filter threads
Series 9	62-85mm filter threads

Series Filters (Series Filter Sizes)
Series filters were originally invented to help solve the problem of many different sized lens filter threads impact on filter costs. A series VII filter can be used in a range of adapters for the popular 49mm to 55mm sized mounts. The series VIII filters range up to 67mm filter thread lenses handily too. The series IX filters covered the 82mm filter thread sizes. A variety of smaller series filter sizes covered the older and slower lenses of the past, but are usually too small for most current SLR lenses.

A series filter usually consists of a colored glass filter with a metal rim, but without filter threads. The filter mounted in an adapter ring that fit the desired filter threads (e.g., 52mm, 67mm) and a retaining ring to hold the filter in. Unfortunately, this design doesn't work well on very wide angle lenses, which may vignette with the bulky height of the adapter plus filter and retaining ring. These series filters were often of excellent quality, but have given way to threaded filter rings, often used with a step-up or step-down adapter as appropriate.

A Grain of Salt
The above points need to be taken with a grain of salt, i.e., some testing in your own photographic situation. If you mainly shoot print film developed up to 4''x6'' in the local mini-lab, your requirements will be less stringent than a professional photographer shooting for a food ad poster. Similarly, if you use high quality filters, you may find that comparisons of slides or prints, with and without your selected test filter, show minimal impact of filter quality on your photographs.

Clean Filters Because...
Filters need to be kept very clean. Scratches in filters from poor cleaning have similar bad effects on contrast as if they were in your lens coating. Consider that a thumbprint on the lens has been tested (by Popular Photography Magazine staffers) to cause up to a 20% loss of contrast! Unless your filters are very clean, you will lose some of the potential contrast that your lens can deliver. Some cleaning scratches or a bit of smudge on even the most expensive filter may make it as bad as any no-name filter in its effects on your photographs!

Protective Filter Effects
UV filters were originally needed with older lenses, especially at high altitudes. Those older lenses passed the UV to the film, where the UV registered as excessive blue exposures. Modern lenses usually use UV cured adhesives which inherently absorb and block UV. So you probably don't need UV filters to block UV on such modern lenses, which already filter out most of the UV anyway. So that's why you will hear that a UV filter (used with some older lenses) had real uses for cutting haze and smog effects, especially for distant mountain and similar scenes. Today, if you really need to cut through haze and smog with a telephoto lens, I would suggest looking at infrared film and filters.

Most UV filters appear transparent upon inspection (and should be color-free). The UV filter may tend to reduce the amount of blue registered in some films, especially at high altitudes, depending on the exact filter curves. UV filters vary greatly in the amount of UV they absorb, from a low around 10-20% to over 90% depending on the UV frequency and filter passband.

A skylight filter is light pink in color, and therefore reduces blue light which it absorbs slightly. You may also see these skylight filters referred to as type 1A or type 1B filters. The skylight filter helps add ''warmth'' to scenes that would otherwise have too much blue coloration.

Both the UV and skylight filters have filter factors of 1, meaning they can be used without changing the exposure setting on non-TTL metering cameras.

Fluorescents and Filter Metering Factors
Naturally, a thru-the-lens metering camera will automatically adjust for most filter factors. A minor point is that metering systems vary considerably in their sensitivity to blue light in particular. A CdS cell may be most sensitive to yellow-green light, while a photodiode may be more sensitive to red or blue light. In sunlight, you are usually okay, but beware when using other light sources! I suggest you check to ensure your meter is reading your filters properly and matching the recommended absorption or exposure correction factors. In some lighting (e.g., fluorescents), some metering systems will be fooled by up to 2 stops or more!

Cutting Filter-related Costs:

A non-trivial cost of shifting lens mounts is the cost of buying filters for your new lens line. Having pentax (49mm) and minolta (55mm) as well as nikon (52mm) cameras makes me painfully aware of these costs. You risk vignetting if you use a smaller filter on a larger lens. Most users therefore opt to buy the largest filter size they need, and use adapter rings (e.g., 52mm -->55 mm) to share filters between cameras.

View Camera and Non-standard Filter Sizes
Many older lenses use non-standard filter sizes that are hard or impossible to locate. The simple solution is to break out the glass from a metal rim filter of the closest next largest size. Now center and glue the filter ring to the lens. With luck, you have converted your problem lens to the new filter ring size.

Slip-on Lens Filters
Some older lenses and many inexpensive point and shoot or similar cameras have no filter rings. Again, the simplest solution is to glue or mount an appropriate filter ring on the lens. Now you can use standard filter sets.

Internal or Rear-Mount Filters
It is often impossible to mount conventional filters on certain lenses, with fisheye lenses being an obvious example. Extreme telephotos of large filter diameter (e.g., 122mm) may not have filters available at reasonable prices. The solution has been to place filters at the rear of these lenses. Some lenses use a filter mount for a smaller, standard sized (often series) filter thread mount. Others provide up to half a dozen preselected filters for commonly used filters in a rotating ring. The alternative 122mm filter thread filters would be perhaps fifty times the cost, but provide equivalent effect.

A version of this approach can be done with regular filters and the lens attachments such as fisheye and ultra-wide angle adapters. See fisheye adapter article for details. These adapters mount on filter ring threads, often using a series VII or VIII adapter. A standard filter can simply be mounted underneath the adapter, acting as a rear mounted filter in similar ultra-wide or tele-lenses.

Wide Angle and Zoom Lens Problems
For larger lenses such as zooms, wide angles, and telephoto lenses, the cost of filters may be an element worth considering. As an example, Sigma touts that some of its wide angle lenses use relatively small filter rings compared to their competition (e.g., 67mm vs. 72mm or even 77mm for some brands for same focal length and maximum aperture). The cost differential for a set of a half-dozen new filters in the larger size may be enough to buy the lens! Similarly, you will usually be unable to use the built-in lens hoods on many telephotos if you are using a larger filter with an adapter ring. The result is either more frustration or more expense, or both.

Actually, it gets much worse when you have to consider wide angle lenses. Here, you may be unable to use thicker filters without vignetting the edges of your photographs. You can't use most step-up rings, as the resulting thickness will also vignette. You often end up having to use very large step-up rings (hint: Tiffen makes these) to go from say 52mm--> 67mm in order to avoid vignetting with your wide angle lenses.

Series Filters for Medium Format and Large Filter Lenses
Used series VIII and series IX filters are often available at surprisingly low cost for 67mm and 82mm sized filters (e.g., $5 and $7 US). I am very fond of the Kodak series VIII and IX all glass series filters, which have very high optical quality for their low costs. I also have many series VII bulk-dyed glass filters of various kinds. Being out of favor, these filters are often a bargain compared to their resin dyed filter replacements.

Resin and Gel Filters
Some filters simply can't be made in bulk dyed glass to achieve the needed filtration curves. So you have to accept dyed gel or resin filters. Naturally, there are high quality and low quality versions of both gels and resin based filters.

The colored gelatin or gel is usually poured and pressed flat (to 0.1mm in some cases) and then mounted between two pieces of flat glass. A higher quality filter maker pays particular attention to sealing the filter into its mount so as to exclude moisture. Gels can also be used directly, whether as lens filters or in the darkroom. Gels can also be used in larger sheets to cover lights and strobes for special effects. While the cost is low to moderate, gels require careful handling or they will get scratched and dirty quickly.

A resin based filter uses a bulk-dyed resin directly. The very best of these resin filters offer many advantages (e.g., Singh-Ray) and sometimes unique filtering characteristics. Higher quality resin filters tend to be rather expensive. On the plus side, they make possible many forms and designs of filters, such as graduated color filters, hard or impossible to get in any other way.

Cokin style Filter Adapters
A logical extension of the gel and resin filter series has been the development of filter systems by Cokin/Minolta, Kenko, Ambico, and others. These systems usually have several sizes of filters available, typically an amateur (Cokin series A) and a professional (Cokin series P) sized filter. The amateur sized filters might cover up to 67mm lenses, for example, using a standard lens thread mounting filter adapter. The larger lenses require the professional series filters (up to perhaps 82mm lens filter threads). As you might expect, there is a huge jump in prices for the larger or professional filter series.

Before you spring for the larger and much more expensive professional sized filters, check to see if you can use the amateur sized filters first. For example, a 72mm lens thread for a telephoto or zoom lens might accept a step down ring (72mm to 67mm) and standard amateur filter mounts. Check for vignetting, both wide open and stopped down. Even if there is some slight vignetting wide open, there may be none discernible stopped down a stop or two. Telephoto lenses and zooms work best for this trick.

Unfortunately, for wide angle lenses, you may have to go the other way (see postings below). A thin adapter ring might be needed to expand from a 67mm filter thread to a larger 72 or 77 mm filter thread size. The ring needs to be thin, as you want to avoid vignetting. You need a 72 or 77mm size filter or adapter to prevent vignetting at the edges of the image. So you might be forced to use larger and much more expensive professional filter sizes with wide angle lenses that are close to the system limits. Some professional filters holders for wide angle lenses forego the multiple filter holding options to provide a low-profile, non-vignetting filter holder for single amateur or professional filters.

Most of the standard amateur and professional filter adapters provide for use of three or even more filters at once. Besides colored filters, you can buy up to 130+ filters of various types. Some are matte filters, others feature rotating prisms, and other unusual special effects are available - albeit at a sometimes hefty price. One of my favorites is the diffraction filter, which converts light sources into rainbows of color. Conversely, I never use the pricey five-prism special effect filter that came with a group purchase.

Buy Slowly
I suggest that you acquire filters slowly, exploring each in some depth, rather than spending a lot of dollars on filters that you may not use often or at all. You also don't need to get every color or depth of filter in each series, but rather pick and choose to match your needs and interests. You may also find that using these filter kits in the field or while traveling is bulky and slow. Many professionals prefer compendium lens hoods which have built-in gel filter holders over these filter adapter systems.

Sources for Filters
Another benefit of the buy-slowly philosophy is the chance to find filters and add them to your collection over time. Many sources such as EBAY (www.ebay.com) auctions and online dealers (see Yahoo listings) plus rec.photo.marketplace provide chances to pick up photo filters inexpensively. Camera shows are another likely place to pick up filters too. Some discounter catalogs (e.g., Porter's Camera Store) list many filters at discounted prices for comparison purposes.

Organizing Filter Purchases
Many articles online and off-line, as well as entire books, are devoted to filter choices. Cokin and Ambico provide guides to their filter choices and examples of their use. Most filters come with sheets listing filter types and uses (the better to sell you more of them ;-). Consequently, we haven't tried to overview all the filters available and the specialty uses of each.

As you acquire more lenses, you may find it valuable to create a list of filters available for each lens. Split dedicated filters of that exact thread from those provided by adapters or filter box kits (e.g., Cokin). Reviewing such a list may encourage you to try out some unusual lens and filter combinations.

This same approach may motivate you to purchase adapters for some cameras (e.g., a B50 to 52mm adapter to let a Hasselblad 500c share my nikon filters). Conversely, it may highlight the lack of corrective filters such as a FL-D (fluorescent to daylight) filter for 67mm lenses. You may also decide to shoot some black and white film, as I did, just for the fun of seeing what the filter effects will be. This experimental approach is the best and most fun way to learn how to use your filters, and direct you in expanding your photographic vision through the use of filters.

SUMMARY:

• You can buy the largest size filters (55mm in my case) and use adapters (e.g., 52 to 55mm) to adapt the filter to use on your other camera system(s).
  

• You can adopt the amateur or professional series filter kits made by Minolta/Cokin and others, and share these filter between your various cameras. I find this slightly bulky in the field and less optimal than individual filters, however.
  

• You can compromise, buying commonly used filters (e.g., polarizers) for each filter thread, but sharing the less often used filters between systems. For some special effects filters, you will have to buy the Cokin or similar kits or equivalent resin filters if available.
  

• You can buy duplicate sets of filters for each size of lens thread in your collection. This approach gets very expensive fast, especially for the larger lenses, and if you are a filter fanatic!
  

David Foy asks me to point out that these prices are dated 15 years ago, so we have had a 67%+ inflation CPI since then, so double these older costs. Still, filters are among the highest markup items you can buy. Hence, filters are a favorite of aggressive mail order and retailers seeking maximum profits from your limited photo dollars!

I recently advised a newbie photo buyer who had shopped around carefully to get the lowest price on a mailorder consumer camera, only to be talked into adding on $130 for four name brand filters! Phew!! Surely this mail order firm made far more profit from the filter sale than the camera sale, right?

You can make a number of serviceable filters relatively inexpensively. Most books dealing with photo filters will describe some common and easy to make filters. Here is a brief overview:

• cross-star
  Usually a neutral color (grey, black) section of window screen put in front of the lens, or cut to fit into a conventional clear (UV, haze) filter, is described. Put more sections to get more cross-stars. Put one screen on back of UV/haze filter (glue with removable household cement). When you want a variable and multiple star effect, pop a second circular piece of screen onto the front, and twist until desired effect is achieved. A small piece of silicon putty (used for holding posters on walls, similar to silli-putty) can be used to hold filters and cutouts in place during temporary use (see other uses below).

  diffuser

  Usually a clear (UV, haze) filter is lightly coated with vaseline (messy, removable) or clear hairspray (see posting below - permanent) to the desired pattern and thickness.
  

  Others suggest a neutral color (grey, black) panty-hose or nylon stocking to provide a similar diffusion effect. In this case, you stretch the section of nylon fabric over the front of the lens tightly. A rubber band can help hold it in place.

  polarizer

  Large polarizers are prohibitively expensive. You can buy sheets (e.g., 8'' x 10'') of polarizer material (e.g., Edmund Scientific Inc) and cut them to fit either a gel holder (squares) or clear UV/haze filter (round). While less rugged and more scratch prone, this polarizer sheet material filter works with reasonable care in use. Keep sheet material filters safe when not in use by packing between stiff cardboard or other protective containers.

  This same polarizer sheet material trick can be used with regular lights to convert them into polarized studio lights. Examples of uses include photos of stress colors in clear plastic (e.g., picnic forks) and crystals on glass (e.g., Vitamin C). Put the polarizer sheet material between the light and the glass sheet supporting crystals or plastic items. Use a snout to eliminate side lighting, and watch for excessive heat if too close to hot light bulb! A second polarizer filter on the lens is rotated until the desired color pattern effects are seen. Same lights can also be used with polarized light microscopy in a similar setup. Neat!

  diffraction (star-burst) gratings

  You can buy sheets of diffraction (star-burst, rainbow effects) gratings relatively inexpensively (e.g., Edmund Scientific Inc.). A single sheet can be cut up into a number of square gratings for gel holder use. Cut circular patterns for 67mm, 72mm, and up to 122mm filter sizes or larger as needed. Again, while less rugged and more scratch prone, the very low cost makes this an option worth looking into.

  You can obviously use these sheet materials directly in gel holders, or simply drop them into clear UV/haze filters (front or back). In some cases, sheet material may interact with glass (e.g., newton's rings). To avoid this, you can use an adapter step-up ring to hold the circle of sheet material in place. I prefer to use a spare Cokin lens adapter ring, since I have some extras, and just glue the sheet material to the ring. I find this more compact than the Cokin filter setup, yet I can easily rotate the adapter ring to vary the effects. Anything that works is fine - lots of people just hold the sheet up in front of their tripod mounted camera and click away. (see posting)...

  cut-out patterns

  You can use a cut-out pattern of a heart-shape, circle, square, triangle, etc. as needed to vignette a desired shape onto film. Just put the cut-out onto a conventional UV/haze filter for ease in handling, or use a 3x5 card or similar cutout holder in front of the lens. Matte boxes are just a convenient way to align and hold these cut-outs.

  Incidentally, you can also shoot out-of-focus highlights from Christmas trees or other point sources of light using a cut-out pattern. You will get some unusual and nifty effects, with each light bulb showing as a colored pattern matching your cut-out pattern. A similar effect is responsible for those donut shaped circles on mirror lenses, which have a central round mirror ''cut-out''.

  color filters (for strobe)

  You can use colored transparent plastic, such as report covers, using multiple layers for deeper color effects. Mounted on your strobe in a cardboard U-shaped mount (with rubber bands to hold on strobe), you will color the strobe light itself. Cut the U-shaped mount(s) out of the slide-on report cover plastic holder and glue in place or use rubber bands. Very handy at night when you want to "paint with light". You can use multiple colors on different strobes from each side of a textured object (e.g., sea urchin shell, styrofoam human head wig holder). Using red and green filters from left and right will result in red and green colors where only one light hit, and yellow where they both lighted a crevice or protrusion on the subject. Interesting fun!

  colored filters (for lens)

  You can achieve color patterns of highly irregular shapes with a piece of clear plastic and colored marker pens. Unlike gels, you can mark in any pattern you want to fit the subject. Cut out plastic where you want sharp image (e.g., Bride's face). The plastic will act as a diffuser, reducing sharpness, and yielding an out-of-focus look. Put a circular plastic plus marker color cut-out into a clear UV/Haze filter for ease in handling.

  Graduated Neutral Density Filter Replacement

  Ansel Adams didn't have graduated neutral density filters starting out, but he did have a dark slide. Setting his camera on a long exposure for a landscape shot, he reportedly simply waved the dark slide back and forth across the top of the scene. The dark slide blocked some of the light from the overly bright sky, reducing the exposure range of the shot and holding back the bright sky highlights. With a larger lens, and perhaps a neutral density filter to make the exposure longer (without altering desired f/stop), you can give this trick a try too. Be sure to bracket several shots, and practice before any critical shots. With the camera back off, on a tripod, you can get a feel for where the blocking cardboard (grey card?) needs to be. Keep the card in motion and allow some exposure on the highlight section. Change the lower point on each cycle, so you get a more gradual dropoff in lighting. Naturally, this trick only works for slower exposures of non-moving subjects like landscapes - but that is where graduated neutral density filters are often used.

  colored gradient filters (for lens)

  You can create a single or multi-colored gradient filter of any complex design (unlike the simple linear top-bottom designs of conventional gradient filters). Computer users can simply use a screen painting program to create a colored printout or screen image that can be photographed onto colored slide film. You can also use colored lights and textured surfaces in the studio to produce unique textured single or multi-colored gradient filters with layouts as desired or needed. The resulting colored slide can be used as a gel, aligned for use, and the image composed and exposed through the filter in front of the lens. Or you can just use the gradient filter as part of a slide sandwich, along with the conventional photo if preferred.

  contrast and colored filters of precise color and contrast (laserprinted)

  see homebrew contrast filters tips using a color laser printer and transparent sheets (note you can make several sets of colors and contrast ratios or color per centages on a single sheet of transparency etc.).
  

  Wratten 87 replacement using developed (unexposed) ektachrome posting...

  Free Filter Samples tip from Jim Franz!

  See Jim's tip posting below for a source of highly useful color filter materials for use in your Cokin or other 3x3inch holders!
  

Related Postings:

From: Harold Bean hibeans@worldnet.att.net
To: Rollei List rollei@mejac.palo-alto.ca.us
Subject: Source for Filters & Adapters

Thought I'd suggest to this illustrious and illuminating group another source for filters and adapters:

The Filter Connection
P.O. Box 155
South Windham, CT 06266
Info: (860) 456-3990
Orders: (800) 882-2832
Fax: (860) 423-2738

I ordered new B&W; filters for my Rollei 3.5 and my Rollei 35S at a very reasonable price. Thought this might interest everyone. Owner is very knowledgeable and courteous.

Harold

Subject: Re: OEM filters vs. independent manufacturers
From: rmonagha@post.cis.smu.edu (Robert Monaghan)
Date: 1998/01/04
Newsgroups: rec.photo.equipment.misc

I recall an article from Shutterbug Ads some 4-5 years ago? (possibly popular photography's SLR column by Keppler, but I doubt that ;-) on this topic.

Basic summary is that for most of us, it doesn't matter. Factors such as SMC or multi-coated filters did very little for light transmission (from 95%-97% raised to 98% to 99% in SMC - big deal.

The highest quality filters had *very* optically flat and parallel glass, but the effects were unlikely to be seen in most slides or photographs.

One caveat is that for some wide angle lenses you need to be aware of filter thickness. For example, nikon's polarizers and filters were thinner than typical, so you might vignette slightly with the wrong thicker filter on a very wide lens. I use nikon hoods too on my ultrawides for the same reason, but suggest that money saved on filters might be better spent on hoods and tripods for most of us ;-)

The best filters were probably the batch glass series filters by Kodak,at least as measured for glass quality, uniformity (all the glass was colored identically) and for optical flatness (superb). In the larger series VII, VIII, and IX sizes, these filters are often unpopular - meaning very cheap, because they are old and require a bulky mounting ring set.

Some series VIII filters were threaded, and since they exactly fit the 67mm threads on my bronica and kowa medium format cameras, I grab em when the price is right ;-) The series IX are also huge and cheap, and optically usually superior to the generic filters of today. The savings can add up fast if you are buying used versus new filters, and even more so if they are unpopular or older series filters, despite their higher quality. Camera shows are a very good way to pick up some inexpensive used filters for a lot less than new prices...

The point on nikon filters being sold to the camera store for $1 in bulk is a good one by the previous poster; what do you expect optically for a buck? But what a great markup ;-) I was surprised to buy a bronica 67mm UV filter only to open up the package and discover the filter had been made by Asahi Optical Corp (Pentax) for Bronica and labeled as such. My bet would be that a lot of relabeling goes on, and that different batches of the same labeled filters might come from different makers, even for the top rated names, and so you may be paying a lot more for the name on the box, not for what is inside ;-)

What perplexes me is why we don't have filter thread to bayonet mount adapters for filters, since if you have worked with either the hassy or rolleiflex bayonet mounted filters, you quickly realize how much faster and easier they are to use and to stack up between use. Even a dual filter mount, one threaded and the outer being a bayonet mount would be a god-send to some frequent filter changers and users ;-) Filters are simply too much of a pain to use with the threaded approach, plus you need to have filter wrenches (Porter's Camera Store) to unstick 'em ...

Most of today's filters of the colored variety are sandwiches of glass and colored resin or plastic. This keeps the costs down, but quality and uniformity vary a lot more. Certain brands (singh ray sp?) are optical quality resins throughout, better optically but less scratch resistant. The various minolta/cokin filters and finally the gel filters are useful adjuncts, but the gel filters have a problem with scratches in heavy use, and are a pain to use outside of the studio in my experience.

A fun experiment at the next camera show is to compare sale filters side by side of the same type, the color variations are astounding. p;-) For some purists, these color variations are a concern, and if you can tell from your slides which were shot with Canon (bluer/colder) and which with nikon (redder/warmer) then you may want to be more picky when buying filters. It isn't enough to buy the same brand, due to different batches and makers used, so if you are a picky pro - you probably want to buy from the same tested batch of UV filters, say, so the effects are the same across your entire canon or nikon line of lenses as the filters are the same batch - plus however many spares you are likely to need in the future ;-) Fortunately, I don't have to worry about this level of detail ;-)

An equally important question is which filters do you need and will you use? this depends on the types of photography you are doing, film you use, and whether you are a special effects freak. Most of us get too many filters that we rarely use, but if your costs are low, they might be a fun way to expand your photography horizons -

enjoy - bob monaghan

[Ed. note: Mr. Brick is a noted photobook author, an engineer designing autofocus camera systems, and an expert on Leica and related optics...]
From Leica Topica Mailing List:
Date: Thu, 16 Nov 2000
From: Jim Brick jim_brick@agilent.com
Subject: filters on Leica lenses, part 1

A human looking through eyeglasses can SEE when the light source they are looking toward is producing flare in their glasses. You CANNOT SEE when a filter is causing flare when photographing with an M camera. R camera yes, M camera no. The image on the film will exhibit lower contrast, perhaps washed out, perhaps double image ghosting, and numerous other flare and bright light source high contrast afflictions, but you will never see it until AFTER you process the film.

This is why Leica says "don't use any filters when photographing a high contrast scene or into a light source." "These situations cause micro flare, macro flare, image ghosting, etc," all via the filter.

All of the surfaces of your lens, especially the Noctilux, are coated to kill these unwanted side effects. The Noctilux spends most of its life looking at high contrast such as night scenes, inside rooms with lights on and deep shadows. Leica has spent millions of R&D; money perfecting lens coatings to transmit as much light as possible without unwanted flare properties. It takes machines costing millions to put the various coatings on the different surfaces of your lenses.

And then you want to nullify one of the reasons your lens cost so much, by putting a flat piece of glass (even good Schott glass) with coatings much inferior to Leicas, which WILL cause the flare problems that the Leica lens coatings are designed to prohibit. But with the filter there, it is too late. The light is already damaged before it reaches the lens. The poor Noctilux is looking through filter flare, just like your eye looking through eyeglasses flare. Take the glasses off and the flare goes away. Take the filter off and the flare goes away.

This is why Leica says:

"Don't use any filters when photographing a high contrast scene or into a light source." "These situations cause micro flare, macro flare, and image ghosting."

So those of you that run around and photograph anything and everything with UV filters on your lenses, are participating in a crap shoot. Point your camera toward a bright light (like the sun, or bright street light at night, or bright reflective white shirt, etc...) will have images with reduced contrast (or worse) due to some level of flare. A naked lens will ALWAYS produce a better image.

Part 2 tomorrow.

Jim (I didn't start this!) Brick

From Leica Mailing List:
Date: Mon, 20 Nov 2000
From: Jim Brick jim_brick@agilent.com
Subject: [Leica] part 2

To begin with, I have to tell you that I use filters a lot. My bags have dozens of filters. Polarizers, ND, split ND, color grad, warming, cooling, red, green, yellow, high quality glass, high quality resin, you name it, I probably have it. Except for Cokin filters and UV filters. I don't like Cokin filters and UV filters have absolutely no use whatsoever.

I use filters when and only when using a filter will ENHANCE my photographic result.

Wouldn't it be really silly to use a filter when it has the possibility of DEGRADING my photographic result?

So why would someone use a UV filter on a modern lens, manufactured from probably 1960ish to present. Certainly not for the UV inhibiting factor.

This question is answered by Zeiss, Leica, (and all other major lens manufacturers) as they have all of the UV inhibitors built into both the lens glass itself and the cement between the elements.

The second part of the question is totally up to you. If you cannot sleep at night worrying about what might happen to your front lens element, put something over it. I suggest a lens cap. That is what I use. That is what they are for. When taking photographs, I use no filter unless the filter will enhance the photograph in some way.

You cannot protect your camera by having a filter on the lens. Dropping or otherwise banging a camera will damage the camera, not specifically the very front of the lens. For every 10,000 camera dents, lens dents, RF misaligned from whacks, other camera-lens mutilations as a result of dropping, whacking, banging, there might be one damaged front lens element (damaged without any metal lens housing being damaged as well.) But I can tell you exactly how to damage your front lens element without hurting the lens barrel...

If you have a glass filter, any glass filter (UV filters are glass) in front of your lens and bash the front of the filter, what do you suppose will happen. Ask Eric Welch. The filter breaks and the shards of glass are gashed into the front of the lens, ripping big gouges in the lens coating. Not a pretty sight. Do you think that something hitting the filter hard enough to break it is going to retract quickly enough to keep the broken filter glass away from the lens? No. If it breaks the filter, it is going to jam it right into your front lens element. How close is the filter to the lens. A millimeter + or -. If something hits the filter and doesn't break it, well, it won't break or damage your lens either, if the filter wasn't there. Front lens elements are mostly recessed. A filter sticks out. This is not rocket science. The BEST protection is to use your head, use a lens hood, and of course use filters when "appropriate."

I have been a photographer since 1950. I live on the pacific coast of California. Neither I, nor any of my colleagues (thousands over the past 50 years) have ever damaged a lens element. I have neither seen (other than the broken filter gouging the lens) nor known of anyone bashing only their front lens element. The salt air and sea/sand spray from the ocean winds have never been a concern either. I have spent thousands of hours along the seashore, photographing waves, rock formations, sunsets, seascapes, wildlife, etc. I still have and use some of the lenses I had at Brooks in 1960. They look today like they looked then. Pristine glass. I breath this air, and it hits my eyeballs constantly. No damage. If sand starts blowing, squint your eyes and take the lens cap out of your pocket and put it on the lens. But this is not going to keep sand and dust from getting into your camera mechanism and lens mechanism. To me, protecting the workings of my camera and workings of my lens is a much bigger concern than treating the front, recessed, small piece of glass as some sacred spot. You can pour water on the front element of your lens. Tip it over and pour it off. Wipe it dry. But don't do this with any other part of your camera.

Hasselblad is built in a factory located in an ocean side city. I attended Brooks Institute of Photography, Santa Barbara CA, and ocean side city. Do Brooks Students use "protection" filters? No. We were taught to only use a filter to enhance some aspect of the photograph. Brookie's spend an inordinate amount of time photographing along the beach, seashore, and in boats. Where's the damage? There is none.

I live in the same area that Ansel Adams lived. I have spent time with him, while photographing along the California coast. He was a very nice person and used lots of filters. But never a UV filter. Not on his view camera lenses, not on his Hasselblad lenses, not on his Conterex lenses, and not on his Leica lenses. He used filters ONLY to enhance a photograph. Quite often a deep red to darken the sky against the white clouds. Quite often, none.

Why don't Large Format photographers use "protection" filters? A large view camera on a tripod is far more unstable than a Hasselblad or Leica. I have seen view camera disasters. Falling forward while on a tripod. What is leading the fall. The lens. I have never heard of a view camera lens (the glass) being hurt. Camera standards yes, lenses no. LF photographers don't use UV filters because they know better. And they have not been sold a "bill of goods" by the camera stores. Camera stores make a maximum of 5% profit on camera and lenses. They make up to 200% profit on filters.

I have taught several Leica workshops for a professional camera store in San Francisco. I was told specifically: "DO NOT TELL THE PARTICIPANTS THAT THEY SHOULD NOT BUY UV PROTECTION FILTERS." I said "why." And they answered "because they are a high profit item that adds to the total profit when we sell a lens." Straight from the horses mouth!

This whole UV protection filter game is a gimmick. UV filters do not "protect" anything except the store's bottom line.

Modern lens coatings are quite hard. You can clean your lens every day with a microfiber cloth and never damage the coating. Some lenses before 1960 (specifically some Leica lenses) had soft coatings. This is why you will sometimes see a Leica lens advertised saying "cleaning marks." These are old lenses. You cannot damage a modern lens, unless you specifically try to damage it. Like putting a filter over it and then smashing the filter.

If you are lackadaisical when driving your car, you can expect to be involved in fender benders. If you are lackadaisical when handling your equipment, you can expect to damage something. Usually the finder, film back, side of the lens (f/stop ring, shutter ring, focus ring), but it would take a certain talent to zero in on just the front element. In fifty years, I have yet to see this happen. I've seen many dented cameras and lenses that won't focus. But no smashed front lens elements. One smashed filter that resulted in a damaged front lens element.

Someone told me that they knew of someone that bashed the front element of their lens, so this is why they have a "protection" filter on their lens. I told them that I know two people that dropped their camera in a lake, and one in the ocean. The M3 that I personally have is a replacement, by Wetzlar, for an M3 that tried to swim in a lake. I also know a person that dropped their camera out of an airplane during an aerial photography shoot. Does this mean that I should put a flotation jacket on my camera when near water, or a parachute on my camera when doing aerial photography? No. There isn't anything that someone, somewhere hasn't done. Does this mean that you are going to do it? Most likely not.

Use a lens cap when not photographing. Take the lens cap off to take photographs. Use filters to enhance your photographic result when possible. When no enhancement is possible, use no filter.

I use filters a lot! But I am very careful of where, when, and why. Do what Leica says. Don't point a filter at a bright light source or high contrast, bright scene.

But above all, be true to yourself. If you really feel that having a UV filter over your lens gives you the piece of mind to not worry about your lens, then by all means, use the filter. The best quality money can buy. Just be aware that there are numerous photographic situations that a filter will cause a marked degradation of image quality and possibly lens damage. You should be knowledgeable of these situations because any filter, not just a UV filter, has the potential of causing you grief. Not using a filter can never cause you grief.

Jim

[Ed. note: Mr. Erwin Puts is a noted Leica lens testing expert and author of various articles and even a CDROM!...]
From Leica Mailing List:
Date: Sun, 5 Nov 2000
From: "Erwin Puts" imxputs@knoware.nl
Subject: [Leica] Degradation with filters

I conducted a numberof experiments to see if and under what circumstances the use of a filter could degrade image quality. In theory, when the surfaces are perfectly plane, the effect would be very small. Note that the Apo-Summicron-R 2/180 has a permanent built-in filter in front of the glass.

Here we have perfectly plane surfaces and the computation of the lens was done with the filter effect incorporated.

Generally we can expect some stray light and obviously some secondary reflections. These latter effects I will neglect for the moment. Stray light and flare around specular highlights are the general degrading effects when using filters. These effects are stronger in situations with high overall contrast and strong light sources in the image and when the lens angle is greater as then the skew rays are more troublesome to correct.

In a coming issue of LFI there will be a lengthier article with comparison pictures to show the effect with and without filter.

Here I will keep it short and note that the image degrading effects of filters do concentrate around bright spots in the image (flare and halo phenomena) and will be stronger when using lenses of wider aperture and wider angle of view and when the object has high overall contrast and intensily bright spots.

On the other hand: a longer telelens at moderate apertures and objects without bright small highlights in dull or overcast weather will not show any effects at all.

Provided the filter is really good and multicoated. Really good means really plane surfaces that are very smooth as any irregularitiesdisturb the passage of the rays.

Erwin

From Leica Mailing List:
Date: Sun, 5 Nov 2000
From: "Erwin Puts" imxputs@knoware.nl
Subject: [Leica] Filters part 2

There has been some interest in the effect of filters in degrading the rendition of very fine details of pictures taken in more normal and not so critical situations. On the assumption that the filter is really good, the degrading effect is quite small, but not alway negligeable. The problem here is that there are so many different circumstances and lenses and filtes etc, that any attempt at generality would have to fail. Let me give you personal experience.

I made many test pictures from a street scene on tripod with several apertures and lighting conditions. In itself a very boring test: take a picture, add filter take picture, remove filter adjust aperture take picture etc. Then I looked at the set of pictures and could not see any difference that would be valid given the statistical variance of the conditions. Projection tests showed a small drop in the rendition of very fine detail, but again, small exposure variations could easily account for this difference too in a number of pictures.

To quantify, but do not see this as the last word on the topic, but as a intermediate result, I would say that the drop in resolution is less than 10%, so in stead of 77 linepairs/mm, you get 70. Or to use another comparison: if you overexpose by more than 1/2 stop from the ideal exposure, the very fine details are gone too.

I have tried quite earnestly to find situations where the degrading effect could be easily visualized (apart from the conditions mentioned i my earlier posts). On axis it is almost impossible and in the field you may see it when using the wider angle lenses.

I keep trying to find a simple setup to visualize the effects in a repeatable way, but till now I hav not found it.

Theory predicts a degradation, but in practice it is not so easy to see it.

Shooting obliquely into a strong light source with a filter is easy and gives the desired proof: flare and secondary images etc. and loss of definition.

In other situations the effect is much more subtle.

Erwin

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

Kendall,

If you look at 99.9% of John's Fielders pictures, you will discover that they are taken within a few minutes of sunrise or sunset. He does not need to filter out UV light as he relies on the atmosphere to do the UV filtering. Also, winds that stir up the dirt are usually nonexistent at dawn or dust.

Please note that all film, particularly pan (B&W;) and color film are very sensitive to blue light. It is not possible to cut off this sensitivity at 400nm (the limit of human light visibility). Before you attempt a test of UV type filters, you should be aware of different filters ability to filter the UV light:

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.]

Based on this table is obvious that a UV and Sky 1A (the most popular filters for standard lens protection filters less UV light than most believe they should filter. This is why my standard filter for all my lenses is the Haze 2A.

I have taken pictures of the same mountain scenes (Colorado high country--10,000 to 14,000 feet) with and without my Haze 2A and the difference is very noticeable. The filters effect is less noticeable when the sun is below 30 degrees to the horizon. Anytime the sun is below 30 degrees, I refer to this as "magic light" as it is warmer in tone that high noon as the atmosphere filters a lot of blue light.

To determine the sun angle for your latitude, try the "Sun Position Calculator" at: http://www.cs.ucla.edu/~simonw/sunpos/

Hope this helps,

Karl S.

P.S. As John uses lama to haul his photographic equipment around the mountains, could the weight of an addition filter be the one that "breaks the lama's back?"

From: bobsalomon@mindspring.com (Bob Salomon)
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Series Filters
Date: Wed, 08 Apr 1998

 vpd1@fyiowa.infi.net wrote:

> Does anyone have information as to what sizes the various
> Series numbers refer to?
>
>        Thanks.                            

IV = 20.6 mm
4.5 = 25.5 mm
V = 30.2 mm
5.5 = 35.9 mm
VI = 41.3 mm
VII = 50.8 mm
7.5L = 57mm
VIII = 63.5mm
8.5/5.5L = 74.8 x 5.6mm   
8.5/8mm = 74.8 x 8mm
IX = 82.6 mm
93 = 93mm
103 = 103mm
107 = 107 mm
119 = 119mm
125 = 125 mm
138 = 138 mm

Most filters are available in all of these sizes from Heliopan.

[Ed. note: Series VIII and IX filters are used widely on various Bronica lenses. These filters haven't got threads on their smooth edges. You mount them in a threaded filter holder that fits the lens filter thread and a filter series hood or filter retaining ring to hold one or more filters in place. On some lenses, you can just pop in the filter, screw in a retaining ring or series VIII lens hood, and there you are. Other lenses may require a lens filter thread to series VIII or IX adapter too.

For example, I use a 67mm filter thread to series VIII holder to hold various Kodak glass series filters, plus a series VIII retaining ring. Adapters let you mount larger filters on smaller lenses. Series VII filters were once popular with earlier 35mm SLR users.

Filter quality of older glass series filters is often very good or better. By standardizing on a given large filter size (series or threaded), you can use the same filters on multiple lenses - Bronica medium format, 35mm SLR zoom lenses, or even view camera lenses of various sizes. Some smaller series mounts use press-on designs, bayonet mount adapters (for TLRs oftentimes) and other specific approaches that merit further study.

Why bother? Because you can get great quality used series filters for 10% of the price of a new glass filter in that size. Many folks go into price shock when they find a large polarizing filter for their new 35mm zoom costs more than the zoom. Series VIII and IX filters offer an out of favor, and therefore low cost, way to get very high quality optically flat glass filters at low cost. ]

[Ed. note: Thanks to Alex for sharing these tests of filters and impacts on photography...]
Date: Mon, 1 Apr 2002 
From:  alexanderkoz@excite.com
To: rmonagha@post.cis.smu.edu
Subject: Re: thanks for note: re: blind filter tests

Hi Robert!

This is the table I promised. I dropped data on filters geometry, assembling
quality, "freedom of movement" and alike which affected the overall ratings.

I think a blind filter test would be a most interesting effort too

Well, not every German filter got SUPER in the fM test below so the results
look quite "objective" for me. Minolta and Hoya suffer most from the test
although 160 lpm and medium contrast sounds more than enough to be honest.

Best regards,
Alex.


                    Circular Polarizing Filters
                     * fotoMAGAZIN (09/2001)
                  Tested with 105mm lens, 400 lp/mm

          Model                 Resolution Contrast Rating
          B+W MRC Slim          300 lp/mm  high     SUPER (5)
          Canon                 400 lp/mm  high     SUPER (5)
          Cokin P164            300 lp/mm  soft     NOCH GUT (2)
          Contax MC             400 lp/mm  high     SEHR GUT (4)
          Doerr Danubia         useless    useless  WENIGER GUT (1)
          Hama HTMC Silver      400 lp/mm  high     GUT (3)
          Hama HTMC Wide        400 lp/mm  soft     SEHR GUT (4)
          Heliopan SH-PMC Slim  400 lp/mm  high     SUPER (5)
          Hoya Pro 1            160 lp/mm  soft     NOCH GUT (2)
          Leica                 400 lp/mm  medium   SEHR GUT (4)
          Minolta II            160 lp/mm  medium   NOCH GUT (2)
          Nikon                 400 lp/mm  medium   SUPER (5)
          Pentax                ??         ??       SEHR GUT (4)
          Rodenstock Jet-Pol    400 lp/mm  medium   SEHR GUT (4)
          Soligor               400 lp/mm  medium   GUT (3)
          Tiffen                300 lp/mm  middle   GUT (3)

MYTabs
ak (2002)



From camera makers mailing list:
Date: Sat, 14 Dec 2002 
To: cameramakers@rosebud.opusis.com
From: "Anders Bj�rklund" abjorklu@narpes.fi
Subject: [Cameramakers] Homemade contrast filters

...

I have been using filters printed with a color laserprinter on transparencies
for a while. I use them for my regular 6x6 enlarger, but i suppose one could
make any size of these filters up to A4 / letter size easily. The thin
plastic films would need some kind of support as the size increases i guess.
This has not been a poblem for me with 6x6 cm filters..

Magenta and yellow are readily available in the printer, so theres no need
for mixing colors. Just make several filters with for example 20%, 40%, 80%,
100% magenta and the same for yellow. Calibrating for different contrast is a
matter of experimenting...


Related Postings on filters are on this page
to speed up downloading of the FILTER FAQ and notes above...



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