UV filters-good, bad or neutral?

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I'm wondering if using a UV filter outdoors can actually make a photo look better than without one (because it cuts out the UV).

Have their been any definitive studies on whether or not a UV filter degrades, adds to, or is neutral to the photograph aside from the lens protection aspects.

-- Tristan (emulsion71@hotmail.com), May 14, 2002

Answers

Early lenses had bad or no UV coatings on their surfaces, so a UV filter would come in use here, but all modern lenses have advanced UV and reflective coatings so in theory a UV filter wont acutally do anything, except protect the front element from environmental nasties. Photographers usually fall into 2 camps, those who never use them (thinking they degrade performance) and those that always use them (because they are scared to scratch their expensive lenses). I only use a UV filter if theres a big chance that the lens can get dirty easily. In actual picture taking situations its only during night shots where you will notice the reflective effects.

-- Karl Yik (karl.yik@dk.com), May 14, 2002.

Modern lens coatings as well as some cements used (in particular by Leica)in even older lenses have great capacity for absorbing UV, so for the most part even at high altitudes a UV filter today has probably very little effect on the image as far as further reducing the bluish cast from UV. A skylight or 81a would be a better choice in those situations. The main draw of the UV filter today in fact is that it really does nothing to alter the image, which is why it's preferred for lens protection. Any added glass surface in the optical path has a theoretical negative effect on absolute lens performance. In my practical experience it must be well below the threshold of human vision, even aided by high-mag ashperic loupes, as I have never seen it. Of course, if the filter is of poor quality or not multi-coated, the chances of image degradation, loss of contrast, flare and ghosting are increased. Some time ago I switched to B+W Multi Resistant Coated filters. If you hold these filters side-by-side with even the multicoated filters by Hoya, Nikon, etc. you will see a dramatic difference in reflections off the surface. The MRC's are so absorbant that you almost can't tell there's glass in them. They are also less prone to smudging and smearing when cleaned, compared to other MC filters, and they are extremely durable. Other MC filters' coatings scratch much more easily. The only drawback to the B+W MRC filters is their propensity for attracting a static charge when wiped, which attracts dust particles like a magnet. A small anti- static brush is now a standard accessory in my bag.

-- Jay (infinitydt@aol.com), May 14, 2002.

UV filters were more effective in a day when B&W films were more blue-sensitive ... Modern panchromatic B&W films have a more even sensitivity across the spectrum than older stock from the '50s-60s. They are useful when you're at high altitude and there's more UV scatter to deal with, help enhance contrast.

For color film work, a Skylight 1a or 1b helps reduce the blue cast that comes of shooting under open clear skies. Most useful with slide film; with negative films you can easily do the color balance filtration required to remove the blue cast after the fact.

Basically, use a filter when you need it. Any filter is additional air- glass surfaces in front of the lens and increases susceptibility to flare and additional places for dirt to degrade image quality. Use a filter when you're in dusty/dirty circumstances that stuff might damage the lens, when you need to filter light to make a specific change to the image on film, etc. ALWAYS use a lens hood, especially when using a filter ... It does more to protect your lens to begin with and has the advantage of reducing flare.

-- Godfrey (ramarren@bayarea.net), May 14, 2002.


I seldom use UV filters. Only when environmental hazards are high such as salt spray in high seas or blowing sand.

Having said that, if you are going to freak out every time a dust particle lands on your front element, then put one on. The important thing is the photographs. Do whatever you need to to get the picture.

-- John Collier (jbcollier@shaw.ca), May 14, 2002.


With Leica Lens, a UV filter is described in the documentation as "not necessary". At least it what appears for my R7 and its lenses.

However, I have equipped all the lenses with UV filters, mostly B&W brand, one is a second hand Leica.

It saves the burden of cleaning the delicate lenses after some acid rain drops fell on it....

But, well, UV filter, it's very neutral as long as it match the quality of the lens... X.

-- Xavier d'Alfort (hot_billexf@hotmail.com), May 14, 2002.



Tristan: I aggree completely with Jay. Their main use is lens protection. MRC coating, particularly B+W is also critical.

-- Albert Knapp MD (albertknappmd@mac.com), May 14, 2002.

Actually - on my 'new' old 21 Super-Angulon, a Tiffen UV/Haze-1 filter makes a BIG difference - but I guess it qualifies as an 'older' lens.

Slides shot with the nearly clear filter are substantially less blue - the effect on Velvia is roughly as great as an 81 (not 81A) filter.

Two caveats: Velvia is notoriously UV sensitive, and I'm shooting pictures at 5,300 feet and above (ye olde Mile-High City), so I get 'way more UV to begin with.

But the filter makes such a difference I can't/won't shoot color without it - even though it DOES have a faint-but-visible affect on sharpness at the corners, where the 21 is 'looking' through the filter at a 40-degree angle.

Most post-1975 Leica glass I've used looks like the SA WITH the filter on, so I think the new lenses do a good job of blocking UV (but you can't smear then on your kids!!).

-- Andy Piper (apidens@denver.infi.net), May 15, 2002.


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