Originally posted by Kerebron Yes, you don't.
Coatings are important on
every air-to-glass surface, not only for physical protection (scratch, dust, water, grease, which is important for front and, to lesser degree, rear elements), but to reduce flares and
improve light transmission. Best coatings have losses of 0.2-0.3 % of light for straight beams in the middle of the visible spectrum. Without coatings, losses increase more or less by an order of magnitude.
lol, thanks I think I understand more now, like shooting a scene from behind a window, of course that window glass matters in terms of how well I see beyond it! doh!
Originally posted by Wheatfield Buy lens hoods for your lenses instead. UV filters are useless except in very rare situations.
Sorry, you should perhaps read my follow up reply, certain hoods I cannot use or are hard to obtain, and I need the filters in a hurry. Hoods are not an option here.
The 4 main prime lenses I am using are DFA 100mm 2.8, FA 50mm 1.4, DA15mm f4 and the DA40mm 2.8 XS.
The DFA 100mm comes with a hood, no issue there, and I tend to leave that hood on, however it is very long hood, so when connected to the lens and placed face down (lens first) into a carry pouch it does become top heavy, if I am taking pics closer to ground level or lying down, there is an increased chance it will topple out due to that weight imbalance, I must remember to use the draw string for that pouch, so it is a tad annoying. Also I have read that that particular hood is not very good in its purpose for the DFA 100mm, hence thinking of ditching it for a more compact lens and instead using a filter for protection. The lens hood of the DFA 100mm doubles the overall length of the lens...
The FA50mm with the rubber hood on, even with the rubber hood collapsed still seems to add a decent recess depth to the front element. This picture best illustrates. Notice the difference between 1st and 3rd image;
In fact the DFA100mm actually has a decent recess as well, it's possible that both these particular lenses will be safer than others due to that recess anyway, for sure they are less likely to be handled in such a way to get a smudge on them (unlike applying a filter where it will have direct contact with possibly my fingers or pouch lining and collecting lint.
I already have a UV Filter for the DA15mm as I needed one to act as an extended to apply ND filters etc.
The DA 40mm 2.8 XS is the only lens actually without a hood or filter, and it has an odd 27mm thread. I don't like the idea of a hood as it then defeats the pancake packaway bonus it has.
Originally posted by Bob 256 I've never used UV filters for their designed purpose. Even with film, I couldn't see any difference with or without the filter in most cases. However, I do use a high quality filter on all my lenses which accept one for the purpose of front element protection. Yes, it's easy enough to clean the front element, but over time, repeated cleaning can damage it's surface coating (and cleaning a front element is hard to get right). Cleaning a filter has the same outcome, but if and when it gets too degraded, it can be replaced at much lower cost than the lens, and the flat surface of a filter is easier to clean. Also, a filter provides some protection against impact and dings (substantial when you consider the cost of a lens).
That said, if I put money into a lens with high quality coatings, I won't put a "cheap" filter with sub-marginal coatings on it. I really want the filter to be invisible in terms of reflections. If there are any doubts about a filter hurting IQ, just do some tests with and without the filter (center and corner). Some filters are definitely better than others in IQ aspects (maybe I should say it the other way around because many are excellent and a few are not so). Price is not a clear indicator here so testing or good recommendations (like this forum's) might be called for. Generally speaking, however, the really cheap filters are usually compromised in optical and/or coating quality.
Originally posted by Alex645 Any additional glass "elements" put in the light path will either improve or reduce image quality. A clean quality filter, preferably slim/thin for wide angle lenses, will have a minimal effect, but I wouldn't say there is zero degradation of IQ. Just one extreme example would be at night with specular light sources. If you like flare, then one could argue it improves your image. A high quality multicoated lens will reduce this effect, but there is still some reflection off the front element that hits the rear of the filter that then re-enters the lens.
Ultimately one has to weigh the risks and priorities of best IQ vs. protection.
And just one other rare anecdote: I once saw a paint gun ball hit a protective filter. The filter shattered and the filter glass damaged the front element of the lens. Without the filter, that lens would have needed a lot of cleaning, but I doubt the soft plastic of those balls would have damaged the front lens element.
It's harder the lay my hands on B+W out here, feel free to link me specific filters you have found that don't degrade
And yes, I shall stay away from paintball games with filters!