Filter vs Image Quality

[argos33]

Hello fellow LF shooters,
I was recently talking to a friend of mine about the following question:

How much does the quality of the filter affect the quality of the image?

He was saying that he can see a discernible difference between filtered shots and those taken just with the lens in terms of sharpness, clarity, etc. I always thought that Hoya and Tiffen filters were middle ground in terms of quality but I believe that's what he was using. He typically shoots 4x5 TMax I think.

What do you guys think? How many of you pony up for the nicer filters? Do you see a difference when using cheaper filters compared to using no filters? I normally shoot 8x10 b&w, and am wondering how much of a difference it would really make.

It seems to me that it would be even more important to use nicer filters for 35 & medium format work given the smaller negative size. I just got a used Hasselblad for a carry around/scouting camera and am wondering if it would worth the expense to get nicer B+W filters for it, assuming I want to make some prints at some point?

Any input or example photos would be great.

Evan

[Eric Woodbury]

First, I try not to use filters, but when I do, I use gels or plastic. They are not too expensive, small, and don't distort the image when using very-wide angle lenses.

I use glass for MF and then Tiffen and Hoya. I have a few better ones in there, but I can't tell.

[Glenn Thoreson]

I prefer not to use a filter at all unless there's a pretty specific reason to do so. Anything you put in front of a lens is going to have some negative effect, no matter how good it is. Whether this effect will actually be visible in the negative is another question. I use all kinds of old series filters with no problem that I can see. More modern filters I use are Tiffen, Hoya and just about everything else. I'm a bottom feeder, you see. The only bad filter I've run across was a generic UV filter. It was so bad, you could actually see it when trying to focus, which was impossible. It totally fuzzed up the image. It was horrible. I thought it was the new lens I had it on and was downright sick that my lens could be bad. Guess how far one of those filters can go with a good strong pitching arm behind it. :D

[sanking]

I don't use filters with LF unless there is a clear need to do so, and if I do I use thin gels. You need to store them well to prevent damage, and they should be replaced from time to time, depending on use and damage.

With good quality thin gels I think it would be very difficult, if not impossible, to prove any image degradation.

If you don't have gels, multi-coated glass would be my next preference.

Bottom line, use best practice and if you do there should be no loss of image quality.


Sandy King

[Don Hutton]

A couple of months ago, I shot a Leica lens resolution test on ultra high resolving film with and without a filter - the filter was a high quality Leica UV/IR filter. There was absolutely no difference in resolution - with and without tested at 150lp/mm. On the basis of that, I believe that any filter of excellent quality should have no impact on image quality, especially on large format where absolute resolution is typically much, much lower.

[Kirk Gittings]

A couple of months ago, I shot a Leica lens resolution test on ultra high resolving film with and without a filter - the filter was a high quality Leica UV/IR filter. There was absolutely no difference in resolution - with and without tested at 150lp/mm. On the basis of that, I believe that any filter of excellent quality should have no impact on image quality, especially on large format where absolute resolution is typically much, much lower.

Interesting, I have always believed, based on perception, that the opposite was true even thoug I use only the best filters. Additional flare in the field may sometimes play a role.

[Don Hutton]

Interesting, I have always believed, based on perception, that the opposite was true even thoug I use only the best filters. Additional flare in the field may sometimes play a role.
Kirk

It was a limited test only for resolution only- it was of interest to me because the Leica M8 basically needs to be shot with a UV/IR cut filter in front of the lens at all times and I had suspected that it must impact resolution... Apparently not! I'm pretty certain that you will loose contrast due to flare under some cirumstances and that obviously has an impact.

[sanking]

Flare is the main reason I use filters sparingly. I am much less concerned about loss of resolution than flare.

Sandy King

[Brian Ellis]

Before Photoshop came along I occasionally used red, green, orange and yellow filters in b&w photography to separate tones that otherwise woud tend to merge and to darken skies. I also used a Polarizer occasionally to reduce reflections and sometimes to darken the sky. That's about it. But everything I formerly did with filters can be done in Photoshop except reduce reflections. So the only filters I use any more are polarizers and then rarely. I've owned and still have B+W filters, Heliopan filters, Hoyas, and Tiffens. I've never noticed any difference in the "sharpness" of my photographs with or without filters nor have I noticed any difference among those four filter brands.

[Hector.Navarro]

I do not have my eyes "educated" to see the difference between nice & nicer filters. I might in the future.
In the meantime I am well aware of the difficulties of focusing things up close with the camera and the impossibility of focusing on a filter with a LF camera.

[Sheldon N]

A couple of months ago, I shot a Leica lens resolution test on ultra high resolving film with and without a filter - the filter was a high quality Leica UV/IR filter. There was absolutely no difference in resolution - with and without tested at 150lp/mm. On the basis of that, I believe that any filter of excellent quality should have no impact on image quality, especially on large format where absolute resolution is typically much, much lower.

My own tests mirror this finding, with regard to resolution. I shot a series of comparison tests with three filters and found no discernable difference between resolution with or without any of the filters.

The real kicker was what filters were involved... a mint Heliopan UV/IR filter ($175), a mint B+W UV MRC filter ($75), and a beat up, ratty, bottom of the used filter bin at the local camera store Tiffen UV filter (free). I cleaned off the Tiffen prior to the test but I still think it was uncoated and not in very good shape. Despite trying to stack the odds, I still could not see any difference between any of them.

I should point out that there was a notable difference in flare between them, but this was when shining a bright light directly into the lens for the test photo.

[timparkin]

The majority of large format shots taken have a peice of plastic in front of them*.. ? The scanned images can have a resolution of 200Mp + depending on the way your measure.. If you had something that was visible on 35 or medium format, it would be obvious on lf..

Tim

p.s. Graduated filters are resin - often not 'optically' flat either...

[Ole Tjugen]

A couple of months ago, I shot a Leica lens resolution test on ultra high resolving film with and without a filter - the filter was a high quality Leica UV/IR filter. There was absolutely no difference in resolution - with and without tested at 150lp/mm. On the basis of that, I believe that any filter of excellent quality should have no impact on image quality, especially on large format where absolute resolution is typically much, much lower.

On the other hand, the effect of optical imperfections worsen with increased focal length. So using a filter that isn't perfectly optically flat with a normal focal length lens will damage the image quality a lot more on 8x10" (300mm) than on a 35mm Leica (50mm) and especially a digital camera (28mm-ish).

Absolute image resolution is lower on larger formats, but the total resolution in the image is higher.

[Armin Seeholzer]

Hi

I saw some Pola tests in german Fotomagazin with almost all cheap and expensive filters and the outcome was thad the german ones B&W, Rodenstock, Heliopan , Leica there was no difference in sharpness Canon and Nikon was also almost as good but Hoya and Tiffen and some no names was really cutting the sharpness of the lens!
The test was done with a very expensive MTF testing machine!!!

Cheers Armin

[eric black]

I also try to use filters sparingly, but find that a polarizing filter is one that can not often be avoided, especially when you take lots of pics with water of some sort or another in them. I have invested in the best glass I could afford, that being B+W and in two cases Tiffen (because I like their warming filters better than B+W).

[paul08]

Do you have a reference? I'm skeptical, since in my experience the Canon and Nikon filters are about the same quality (maybe not even as good) as a regular Hoya MC.




Hi

I saw some Pola tests in german Fotomagazin with almost all cheap and expensive filters and the outcome was thad the german ones B&W, Rodenstock, Heliopan , Leica there was no difference in sharpness Canon and Nikon was also almost as good but Hoya and Tiffen and some no names was really cutting the sharpness of the lens!
The test was done with a very expensive MTF testing machine!!!

Cheers Armin

[David Karp]

I have no way to prove this, but I would find it hard to believe that any of us could tell the difference in image quality between a photo that we took in the real world using a filter, and the same photo without the filter. (The exception would be in situations likely to cause flare.) We would see the impact of the filter in many situations, but probably not a noticable difference in image quality.

Same thing between filter brands. For years, I used old uncoated filters. Now I have some nice B+W filters, and some coated Hoya and Tiffen filters. As far as I can see, there is no difference in image quality.

I was worried about the impact of my old filters, and that is why I invested in the nicer filters. It is nice to have them, but I could have saved the money.

[Brian Ellis]

Hi

I saw some Pola tests in german Fotomagazin with almost all cheap and expensive filters and the outcome was thad the german ones B&W, Rodenstock, Heliopan , Leica there was no difference in sharpness Canon and Nikon was also almost as good but Hoya and Tiffen and some no names was really cutting the sharpness of the lens!
The test was done with a very expensive MTF testing machine!!!

Cheers Armin

Joe Englander published the results of his extensive testing of various brands of polarizers years ago in the old "Camera and Darkroom" magazine. His tests showed that different brands of polarizers produced different color casts. But there was no suggestion that they differed in any other way. I have B+W, Tiffen, and Hoya polarizers and don't think there's any difference among them but I'd certainly be open to correction on this by a well-conducted test. I assume there's no English version of the tests done by the German magazine?

[Drew Wiley]

Sandwiched filters like Tiffen or polarizers will absolutely, positively affect image sharpness. Might not matter for some things, but precision big enlargement will inevitably be compromised a bit. Uncoated filters also tend to attract condensation and smudges. Just common sense optics. Flare is an additional consideration. Whenever possible, I use only multicoated filters. For color work I try to make adjustments in the darkroom whenever possible, and avoid filters altogether, although
in some kinds of commercial work they're necessary for light balancing,etc. And I only
use glass filters in the field; plastic filters or gels are just too fragile, get scratched and hazed.

[argos33]

I think it is safe to say that everyone here uses a filter only when necessary. I am referring to those situations where it is unavoidable. Obviously the filter is going to have some effect, we were merely discussing how much. Thanks everyone for the responses. I will ask Jim if he has some example negatives that I could see (and possibly scan and post).

[Nathan Potter]

Without going off thread too much I hope - - What about a filter on the rear side of the lens? Would one expect more image degradation with rear mounted filters than front mounted. I have done this occasionally out of desperation and I believe seen no significant adverse effects.

Nate Potter, Austin TX.

[Bob Salomon]

Without going off thread too much I hope - - What about a filter on the rear side of the lens? Would one expect more image degradation with rear mounted filters than front mounted. I have done this occasionally out of desperation and I believe seen no significant adverse effects.

Nate Potter, Austin TX.

Of course. Not only will any defect or mark on the filter affect the image quality the filter will also shift the focus by about 1/3rd the thickness of the filter material.

Any filter or glass or plastic place inside or behind the lens has to be computed by the lens designers to be part of the optical system. Filters belong in front of the lens with very few exceptions.

As to seeing degradation. The lenses most affected by filters are long focal length lenses. The longer the focal length the more critical that the best quality filters are used.

[neil poulsen]

I have a lot of respect for Bob Salomon's knowledge of photography and equipment. It's always reassuring to know that he's there, ready to bring some particular photographic insight to the conversation.

With that said (:)), I don't have a problem with placing filters behind the lens. I think that the most important consideration is for the photographer to compose and focus the image with the filter in place. In that way, he or she can take into consideration any negative effects that the filter might have on the optical system.

For example, Ansel Adams recommended placing two filters on either side of the camera, versus placing them both in front of the lens. This avoids inter-reflections between the filters that can negatively affect the image.

Since I don't have data, I'll lay claim to a belief. I believe that, because of the large quantity of light, reflections off the lens front can manifest themselves on the rear of the filter and negatively impact the image in way that won't be nearly the case with the filter mounted behind the lens. I would be interested in other photographers' perspectives on this point.

With all this said, I tried a comparison once where I enlarged an image with and without a Kodak Wratten neutral density filter placed below the enlarging lens. I was quite surprised at the difference in image quality. Of course, I adjusted the f-stop to offset the lightening of the image by the ND filter.

So, maybe better to use filters only if needed, regardless of whether they're placed before or behind the lens.

[Bob Salomon]

Neil,

Thank you for your comments. However, it is important to note that this is not Ansel's days. And filters, lenses and coatings are many times improved from those days.

While many filters and lenses are still manufactured with older coating technology and some filters are still not coated when they should be, modern filter coatings like Heliopan's SH-PMC ensure that 99.9% of the light that strikes the filter passes through the filter to the image plane. Lesser filter technologies do not pass that much through to the image plane and that is flare.

Using modern technology coatings flare is not an issue with filters.

As to observing degradation with a filter behind the lens - it won't work. If you have a light fingerprint, for example, on the filter you won't see the degradation on the groundglass but in a comparison of two shots, with and without the filter with the fingerprint.

[Toyon]

Neil,

Thank you for your comments. However, it is important to note that this is not Ansel's days. And filters, lenses and coatings are many times improved from those days.

While many filters and lenses are still manufactured with older coating technology and some filters are still not coated when they should be, modern filter coatings like Heliopan's SH-PMC ensure that 99.9% of the light that strikes the filter passes through the filter to the image plane. Lesser filter technologies do not pass that much through to the image plane and that is flare.

Using modern technology coatings flare is not an issue with filters.

As to observing degradation with a filter behind the lens - it won't work. If you have a light fingerprint, for example, on the filter you won't see the degradation on the groundglass but in a comparison of two shots, with and without the filter with the fingerprint.

On the B&H website Heliopan filters (67mm) for black and white do not indicate any coating. Are these uncoated, single-coated, or multi-coated?

[Neal Shields]

Several years ago, I think in Phototechniques magazine there was an article showing a compairison in resolution between a B&W photo without a filter and one taken with a "band pass" filter. The difference was dramatic.

Point is there should be some resolution increase anytime we reduce the spectrum that a lens has to deal with.

[Brian Ellis]

Several years ago, I think in Phototechniques magazine there was an article showing a compairison in resolution between a B&W photo without a filter and one taken with a "band pass" filter. The difference was dramatic.

Point is there should be some resolution increase anytime we reduce the spectrum that a lens has to deal with.

That's interesting (I assume you mean "resoluion decrease").

I've considered performing some tests myself but it's always struck me as a difficult test to perform with b&w filters since the effect of a filter, if any, presumably varies depending on the colors in the scene. Any chance of being more specific about the time frame of the Photo Techniques article? I subscribed for many years and still have some back issues somewhere. Thanks.

[Bob Salomon]

On the B&H website Heliopan filters (67mm) for black and white do not indicate any coating. Are these uncoated, single-coated, or multi-coated?

All Heliopan filters, except diffusion, soft focus types are fully coated.

Heliopan offers their standard coating and their SH-PMC 16 layer (8 per side) multi-coating. With filters for B&W the SH-PMC coating is a special order and dealers do not stock them. With UV, Protection and Circ Pols dealers do stock the filters with SH-PMC coating. B&H is a smaller Heliopan dealer. Samy's is a much larger Heliopan dealer.

[Nathan Potter]

Neal is theoretically correct - there should be an increase in the resolution of a lens when the bandwidth of visible light is reduced. The principle has been utilized for years in the IC industry where imaging optics can be designed for single emission peaks in mercury high pressure bulbs (430, 365, 290 nm) for instance. Currently laser sources have even narrower peaks so yield very high resolutions (due also to shorter wavelengths of course). However narrowing the bandwidth also can drastically reduce the light intensity since the total illumination from any subject source is the sum of the individual wavelengths from that source as seen by both lens and film. Most photographic sources are a very mixed color spectrum so selecting a bandpass filter for a B&W representation of a scene could produce pretty wild results. The only predictable illumination source is a classic black body radiator which can be run at a known degree Kelvin temperature. Using bandpass filters is a bit of an intrigueing idea though - anybody here fooled around with this?

Nate Potter, Austin TX.

[Neal Shields]

No I meant increase. With a band pass filter you almost have a single wavelength of light. That makes it very easy to focus in one spot. This is why you use a yellow filter on a convertable lens when only using a single element. The single element does well for everything but cromatic aberation. So to get the quality back you use a yellow filter to get rid of the blue end of the spectrum.

Just to keep you digging through you old magazines there was an excellent article about the compromises in lens design in the Leica magazine that got into this.

[Drew Wiley]

Narrow bandpass filters are really far-fetched for general photography. They might be
used in tricolor cameras, where three color separations are made directly in-camera, or
in Technicolor movie cameras. It's an esoteric subject unless you're into optical engineering or some sort of industrial setup. I've gotten involved with that stuff in special color enlarger design.

[john borrelli]

Might be a little off topic, but the best quality filters come into their own, not necessarily for their image quality but for their "joy of use".

I own a few B&W brand multicoated filters. They seem heavier and of a better mechanical quality than your typical less expensive filter and they don't seem to get stuck on my lenses when out in the field and also, the different parts of the filter do not seem to loosen to the point of disassembling themselves.

I also like my Singh ray grads but the screw threads on the Cokin holder rings are far less then a joy to deal with. For me,add winter weather, winter gloves and fiddly filters and joy of use can be a real issue.