UV Filters - Do They Enhance Haze and Fog??

boojum

boojum

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I use filters on all my lenses for two reasons. Most of what I shoot is on an M-9 or an M-8.2 so a UV/IR filter is a must to correct color and also to protect the lens itself. Filters are way cheaper than lenses. And I have some old lenses which cannot be replaced, like the CZJ 272nnnn, the Amotal, the Bertele and some old KMZ J-8's which are quite good. I also have a factory lens on the X2D, the XCD 55V, a very nice lens. And you can be sure that there is a good UV filter screwed on the front of it, a B&W.

I took some shots last night and noticed that what I "saw" differed from what the X2D "saw". The X2D saw haze around lights. Now I know that head-on light can cause glare. But is it made worse with filters? I am curious. But not yet curious enough to get out the tripod and test. I may have to do that. But before I do, any opinions? We always have opinions. ;o) https://www.flickr.com/gp/sandynoyes/153794q75B
 
Strictly speaking any extra glass surface in front of the lens increases the propensity for glare, etc. but good, multi-coated filters usually don't, at least not perceptibly. Occasionally you may have a filter that looks alright but still gives problems. I have a Leitz polarizer that looks clean but, in actual use, it paints photos over with "romantic" haze. I 've no clue what's wrong with it.

At the risk of stating the obvious, was your filter clean from smudges, dust etc.?
 
telenous said:
Strictly speaking any extra glass surface in front of the lens increases the propensity for glare, etc. but good, multi-coated filters usually don't, at least not perceptibly. Occasionally you may have a filter that looks alright but still gives problems. I have a Leitz polarizer that looks clean but, in actual use, it paints photos over with "romantic" haze. I 've no clue what's wrong with it.

At the risk of stating the obvious, was your filter clean from smudges, dust etc.?
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Valid question. I checked it before I went out last night and just re-checked it. It is clean and clear. So it is just the magic of glass and optics. ;o( I will just have to either be more careful or expect results like those. I have noticed it with M-9 pics, too.



Lesson learned. As this weather is not a rarity I can go out with the tripod and shoot a test. Just one more thing to be aware of. Keep the light behind me unless I am damned clever, or want to play at artsy.
 
I use filters only when I want to filter light in particular ways, or do some other specific job.

Once upon a time, I fitted UV and Clear filters to protect lenses as a matter of course. I never damaged a filter on a lens, and I never damaged a lens front element either. I did I just because everyone seemed to feel it was a good idea, and I went along with that.

Over time, I noticed that the lenses I used most of the time, all filter clad, were not as sharp as they once had been. I took the filters off and found the lenses had a thin fog on the front element. I cleaned the lenses and filters, put them back to use. A few months later, the same thing. "Hmm," I said to myself, "I guess I have to take the filters off every couple of weeks to clean inside." The lenses I had no filters on didn't seem to get dirty, the one I had filters on did. "Hmm again: If I have to clean the lenses with filters more frequently, well, that's about as good an opportunity to damage a front element as if I only used a filter when I needed one, since I don't often have to clean those lenses." So I took off all the filters and went shooting with my lenses. And I noticed that I got less flare, slightly better sharpness, most of the time.

That was in about 1980. Since then, I put filters on only when I feel I need one to protect a lens in a specific circumstance (like going to the beach, or photographing in a dust or sand storm) and when I need to filter light. I've still never damaged a lens's front element .. I use a hood *all* the time to protect the lenses and to improve flare control. I feel I'm getting the most my lenses can offer.

Others feel differently. Nothing wrong with that ... do what makes you feel good and returns the results you like.

G
 
Godfrey said:
I use filters only when I want to filter light in particular ways, or do some other specific job.

Once upon a time, I fitted UV and Clear filters to protect lenses as a matter of course. I never damaged a filter on a lens, and I never damaged a lens front element either. I did I just because everyone seemed to feel it was a good idea, and I went along with that.

Over time, I noticed that the lenses I used most of the time, all filter clad, were not as sharp as they once had been. I took the filters off and found the lenses had a thin fog on the front element. I cleaned the lenses and filters, put them back to use. A few months later, the same thing. "Hmm," I said to myself, "I guess I have to take the filters off every couple of weeks to clean inside." The lenses I had no filters on didn't seem to get dirty, the one I had filters on did. "Hmm again: If I have to clean the lenses with filters more frequently, well, that's about as good an opportunity to damage a front element as if I only used a filter when I needed one, since I don't often have to clean those lenses." So I took off all the filters and went shooting with my lenses. And I noticed that I got less flare, slightly better sharpness, most of the time.

That was in about 1980. Since then, I put filters on only when I feel I need one to protect a lens in a specific circumstance (like going to the beach, or photographing in a dust or sand storm) and when I need to filter light. I've still never damaged a lens's front element .. I use a hood *all* the time to protect the lenses and to improve flare control. I feel I'm getting the most my lenses can offer.

Others feel differently. Nothing wrong with that ... do what makes you feel good and returns the results you like.

G
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Very strange behavior. How could the lenses get dirty if they were, in effect, sealed from the outside world? I am stumped.
 
Perhaps a form of internal haze in the front element-filter micoenvironment. My hideously expensive 35 Summilux now has no filter. (Lost the hood with series VII filter in it.) I’ll keep it that way. Ten years plus with the Fiji X100 also nearly always without filter. They’re not necessary. Except for photographing welding maybe.
 
Richard G said:
Perhaps a form of internal haze in the front element-filter micoenvironment. My hideously expensive 35 Summilux now has no filter. (Lost the hood with series VII filter in it.) I’ll keep it that way. Ten years plus with the Fiji X100 also nearly always without filter. They’re not necessary. Except for photographing welding maybe.
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And on the M8/M8.2 and M9 who have IR problems.
 
Night shots- you can get reflections off the filter, pronounced if it is uncoated. About the only time I might remove a filter.
Polycarbonate lenses can outgas over time, building up haze.
When it is humid, and the temperature is cold- the filter will fog up until it clears, but so will a front element.

Every shot I have ever posted in this forum, Flickr, Imgbb, cameraderie, has been shot with a filter on the lens. I keep them on all of my lenses. You have seen the images, enough to judge by. I have enough examples of front elements from Sonnars, J-3, and J-8 optics to see effects of not having a filter.
It is especially important to keep the coatings of very old lenses protected. Especially important for uncoated optics that have Bloom, you do not want to wipe it off during a cleaning. Get a good multi-coated filter for use on those.
 
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For the Leica M9 - the UV filter is important as the BG55 and S8612 cover glass lets through UV, well past what most lenses are corrected for. The M8- problem is in the IR.
The M240- more IR leakage than the M9, and I have not tested for UV yet. The M9- I tested with/without UV, made a large difference.

I do not know the spectral response of the Hasselblad. Worth an experiment- do you have a UV lamp?
 
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L1027521.jpg
Voigtlander 50mm F1 Nokton, UV lamp, Leica M9- with the filter that I normally keep on the lens: a Nikon L37c Multicoated filter. A L39 would even be better, but they tend to be older single-coated.
NOTE: DO NOT SCREW a Nikon filter into a 50/1 Nokton without remounting the glass in another filter ring or using a spacer. It will hit the front glass. I remounted the glass in a Tiffen filter ring.
You can see the large difference made with UV light shining through the filter. On the M Monochrom, the UV filter makes the image sharper as most lenses are not corrected for UV.

SO- use of a filter will depend on the spectral response of the imaging device, whether CCD, CMOS, or film and the lens used. I chose this one as it is modern, and some people believe that modern glass makes UV filters unnecessary. I read a lot of M9 users complain that some lenses, like the 50/1.1 Nokton suffered from "Purple Haze". Mine did not, because I used a UV filter.

This filter/no filter debate has gone on since before photography forums were on the Internet from the age of Pop and Modern Photography.
A meaningful test would be to do a 2D FFT on test images taken with and without a UV filter. Maybe in a few months when I retire. I already have the code to read the DNG files and a mixed-radix FFT, all in Fortran. But if anyone else has such images- feel free to post.
 
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boojum said:
Very strange behavior. How could the lenses get dirty if they were, in effect, sealed from the outside world? I am stumped.
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I always figured it this way: Camera lenses are not entirely sealed, in general. They might be sealed against water incursion from the outside, but inside there is air between elements, spaces that change size and shape, move as you work the focus (and the zoom if it's that type of lens). Lens filter threads are not a hermetic seal, they're just a threaded coupling, so they can leak tiny amounts of air as well.

Fitting a filter on the end of a lens and leaving it there all the time, you've introduced a small, semi-sealed chamber at the end of the lens assembly. There's a certain amount of pumping action in the use of the lens due to focusing and such, drawing air to displace it from the camera body in general, but that doesn't mean it doesn't also draw some air in and out of the filter/front element space as well. Tiny amounts of air, carrying tiny, tiny bits of dust. This very fine dust is small enough that the natural electrostatic properties of matter at the molecular scale will attract it to the back of the filter and the front of the lens front element, over time, and there are no large airflows in that space to unseat it back into the atmosphere.

Thus a very fine haze of very very fine dust particles builds up, and starts to scatter light ... just a tiny bit ... cutting sharpness and contrast by a tiny bit. And you have to physically clean it off to restore the transparency of the filter and the front element of the lens.

This is my conjecture. It is what I believe makes sense as to what's happening. No one I've ever talked to has been able to tell me that it is actually that way, or whether some other mechanism causes the build up of haze that I observe. But in forty-plus years of leaving filters off my lenses, they've stayed clean (modulo an occasional puff with a hand blower, or a wipe with a lens cloth because I put a big thumbprint on the glass...), they've never been damaged, etc.

Always use a lens hood (and a lens cap when the camera is not in use) to reduce flare and protect the front element, use a filter when it's needed to filter light. That's my rule and I'm sticking to it. 🙂

G
 
Haze builds up in a lens as lubricants outgas. Mostly this is found on each side of the aperture blades. I've also seen haze on internal elements- air contracts and expands with temperature, the elements are not (usually) vacuum tight. If the air is moist- it will condense internally. I've had that happen on lenses that were sent air mail.

I could layout dozens of unusable front elements of lenses that I've kept during the years, after parting out the rest of the lens. Usually J-3 and J-8 optics bought for Sonnar conversions. The best J-3 lenses are the ones where the focus was so far off that no one used the lens. I fix those. Second best- those with filters on them from ages ago. Rare.

Some classic lenses, especially Leica and the 5cm F2 Sonnar use very soft glass for the front elements. Keep a filter on those. Keep one on the Bertele.

The M Monochrom will be easy to run through the FFT.
 
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Sonnar Brian said:
Haze build up in a lens as lubricants outgas. Mostly this is found on each side of the aperture blades. I've also seen haze on internal elements- air contracts and expands with temperature, the elements are not (usually) vacuum tight. If the air is moist- it will condense internally. I've had that happen on lenses that were sent air mail.

I could layout dozens of unusable front elements of lenses that I've kept during the years, after parting out the rest of the lens. Usually J-3 and J-8 optics bought for Sonnar conversions. The best J-3 lenses are the ones where the focus was so far off that no one used the lens. I fix those. Second best- those with filters on them from ages ago. Rare.

Some classic lenses, especially Leica and the 5cm F2 Sonnar use very soft glass for the front elements. Keep a filter on those. Keep one on the Bertele.
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The Bertele is never naked. All my lenses are filtered. Again, the Leicas I use need the UV/IR filter and other lenses, like the XCD 55V are covered as it is just a good idea.
 
Sonnar Brian said:
For the Leica M9 - the UV filter is important as the BG55 and S8612 cover glass lets through UV, well past what most lenses are corrected for. The M8- problem is in the IR.
The M240- more IR leakage than the M9, and I have not tested for UV yet. The M9- I tested with/without UV, made a large difference.

I do not know the spectral response of the Hasselblad. Worth an experiment- do you have a UV lamp?
Click to expand...

No UV lamp here.
 
Sonnar Brian said:
The flood lights are shining straight into the camera lens- which lens is this?
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This is similar, but not the same and almost no problem with a J8 and the usual UV/IR filter. The atmospherics did not seem that different but may have contributed to the difference.



The image under question:


And another image taken at the same time, same place, facing away from the lights:

 
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Sometimes you just get flare and reflections, and something strange happens.
The original question: an interesting one. UV filters cut through Haze that softens images. Like in "Hazy Shade of Winter", I am listening to right now.


but covered by the Bangles... did not know that.

The classic-



SO- The UV might cut down on haze, but leave Fog in the visible region with more contrast.

Mine is a Lab grade UV source. Use it to clear yellow damage to thorium glass.
 
Yes, the music seems like only yesterday. Biased as I am I see it as a wonderful period in popular music. It was an outburst of new pop musical thought. As Dylan said, "Tin Pan Alley is dead. I killed it." The names like Strawberry Alarm Clock, Ten Wheel Drive and Lothar and the Hand People will not be equalled for a long while. And as biased as I am I do not think the music will be bested for a long while.

As for UV and haze blooms and glow, it is known and not entirely predictable. The old axiom of keeping the light behind you still holds and variance comes with risk. But it is always worth a try. ;o)
 
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