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back alley

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over the (far too) many years that i have practiced this hobby, i have had an on again off again (literally) relationship with uv filters.

most times the use of a good filter over rides that nagging feeling in the back of my head that says...NO FILTER!, IT DEGRADES THE IMAGE!

protecting that front element wins out.

and what's really weird is that i have never scratched a filter so my lenses would have been safe without them.
 
Ever since a lens cap slipped off a camera in a bag - and then either scratched the lens slightly or let something else scratch it - I've been using filters more than more. The lens is still totally usable and only worth a few hundred - trivial compared to many of the lenses here - but it was enough to make me paranoid.

I take filters off when shooting at night but other than that, I haven't had any significant issues. I was already using filters frequently though anyway as I shoot mostly black and white, etc.

Edit: The short answer is test it yourself. See if it degrades the images you shoot. If not, determine if the added protection gives you any piece of mind, etc. Then make your own call. Everyones is different. [not specifically targeting the back alley with that statement, just sharing my personal general personal philosophy about common wisdom. 🙂]
 
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Personally, i use filters to protect the front element. It frees my mind off a little bit when i am out and about shooting rather than having to consciously remind myself to be careful with my lens

With the filter plus the hood, i almost never use lens caps - too much fiddling around for me, on and off and on and off.

Also, i am not convinced that I can see a difference in IQ with or without filter... my 2 cents
 
I seem to recall that Mr. Hicks recently mentioned that he knows of no tests that prove degradation from using a good filter. (correct me if I am wrong).

Also, as I have mentioned before, I like the quote of the late Mr. Ed Romney in his camera repair books: "Keep the lens clean, don't keep cleaning the lens." YMMV
 
As I regularly degrade images, there's doubt a filter would even be noticeable. Usually I carry a camera with a filter on the lens in lieu of a cap. Makes for faster shooting.

With rare exception, the glass of most filters is the same - nice and flat, transmits visible and nIR and a bit of UV. The difference between a good filter (Heliopan, B+W, Nikon, Leica, etc.) and a cheap filter (Tiffen, Hoya, PRO, etc.) is the metal the ring is made from. Brass is best, then steel, and finally aluminum. The more brittle (aluminum>steel>brass) the metal, the more likely the filter will become stuck, and require mechanical assistance in removing it.
 
Filters are certainly good protection where the conditions warrant (especially salt spray), but I prefer to operate without them. In some conditions they can cause trap reflections in light bouncing between the front lens and the filter, as in the attached shot. I just watch for these conditions and avoid using the filter if I can. (Image processing exaggerated to show the reflections.)
 

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I've never seen any degradation even from cheap filters, not even with pixel peeping. I put one on a lens when I take it new out of the box and a filter lives there throughout it's life. I have cracked filters, but they have saved the front lens element. Good enough for me.
 
Allegedly, cheap filters can degrade the image if you're shooting long lenses; the longer the lens, the more the degradation. I've not tested this formally, so I don't know, but I have tested resolution with 'normal' lenses, and I needed to use 3mm window glass to see a difference. Everything else (glass or plastic) was fine. Also, anecdotally, I rarely shoot my 200/3 Series 1 without a (Soviet-era) orange filter, almost always with the camera (Nikon F) on a tripod, and it looks pretty sharp to me. The only time I remove UV filters is when the sun or another light source is in shot -- and then, not always. Certainly, reflections are far more important than loss of sharpness, and even reflection problems are rarely important. Often they can arise without the filter, in any case.

Ctein, who is a far better experimentalist than I, agrees about general image degradation. But, as ever, few people ever do conduct formal experiments, and of those that do, you can sometimes see from their reported methodology that the experiment was worthless. Usually, those who worry about image degradation rely on one of three things: anecdotal evidence, or what 'everyone knows', or theory.

In the last case, yes, there must always theoretically be some image degradation, but everyone who has set up a reliable experiment has come to the same conclusions as Ctein and me, viz., that you can't actually demonstrate this theoretical loss in a real world image, so the theory is not worth worrying about.

Like Pickett, I've smashed filters (well, I've smashed one on the 200/3 and Frances smashed the other on a 35/2,8 PC Nikkor) and in both cases the camera lens was unhurt.

Cheers,

R.
 
My guess is that image degradation can come from flare more likely than a resolution drop, and this really depends on the location of the front element, of the filter and of the hood.
I don't like to toss a good filter, but I recently did after a small "incident" that totally scratched one, and it reminded me that I would have to toss a very good lens would I have not used a filter...
 
Roger Hicks said:
Allegedly, cheap filters can degrade the image
Click to expand...

Is that comment purely for UV filters or for 'coloured' ones also? I recently tried two different filters - red (Jessops) and orange (Hoya) - when shooting the same scene: compensating the exposure in each case. Once developed, the first image wasn't as sharp as the last one.

Best regards,
RoyM
 
Dear Roy,

Mostly UV, though I did once (many years ago) try Cokin, as 'everyone knew' that 'plastic' filters were 'no good'. I found no image deterioration, though it was more of a quick test than a proper experiment.

Cheers,

R.
 
sanmich said:
My guess is that image degradation can come from flare more likely than a resolution drop, and this really depends on the location of the front element, of the filter and of the hood...
Click to expand...

The other type of degradation often overlooked in "tests" is astigmatic and chromatic smearing at the edges. This can be very evident with wide angle lenses where the light forming the image at the edges passes through the filter at a significant angle.

I did a test quite a number of years ago with a decent by not great Soligor 21mm f/3.8 and an excellent Zeiss Skylight filter (a real Skylight with a rose/pink cast). I was testing to see if the then new Kodachrome 25 would see the color tint (I didn't). I shot at a middle aperture (probably f/8) where the lens, from experience, worked its best. When I examined the image closely I noticed that while I saw no sharpness difference in the center, there was a distinct radial smearing in the shot with the filter. This was with a lens that wasn't particularily great at the edges itself, so the additional smearing addid by the filter had to be significant to be seen.
 
I've had a filter smashed and lens saved after my camera bag slipped off and hit the pavement. Also had some that were scratched, but lens was saved.

I tried an experiment shooting bright lights at nighttime. I used uncoated, single coated, and multicoated filters. There was noticable ghosting and flare around the light sources with the uncoated filters, less so with the single coated filters. Multicoated filters performed the best, even though occasionally they would register a very faint ghost. Based on this experience, I used Hoya S-HMC. Nikon was almost as good, but Nikon stopped making UV filters.

Now that I'm using Leica in addition to Nikon, I've been using B+W HMC only because they and Heliopan make these small sizes (34mm on an Elmar 9cm f/4 from the 1930s, and 39mm). Heliopan's multihard coating is a disappointment. Not as hard as the rest in my view (scratched one already carrying the lens around uncapped in my case), and seems to have more reflectivity than the B+W. The B+W often looks invisible, but I can see the Heliopan glass by its reflection. Oh, and Heliopan costs quite a bit more (up to 50%) than the B+W. I agree with the findings of the testers from Poland!
 
Allegedly, cheap filters can degrade the image if you're shooting long lenses; the longer the lens, the more the degradation. I've not tested this formally, so I don't know,

I've never had any problem with long, fast lenses with a UV filter. Look to the very short lenses over small digital sensors for serious issues. In fact, I've seen cases where there was a mild precipitation on the filter that rendered clearly on the image.
 
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