Cody21 wrote in post #5625027
This topic begs the question (not meaning to hijack this thread). I bought a UV filter as a "protector" for my expensive lenes. Do you people attach & remove your "filter" for specific shots? (e.g., landscape, indoor bright ligts, etc.) It's sounding like you do (ala the OP's issue). I've always just left mine on and wondering if "tack sharpness" of certain shots could be improved.
As you likely know, this question/debate recurs at semi-regular intervals; there are those that always use them, those that never use them, and of course some that fall in between, taking them off in "dangerous" situations.
It is likely that if one uses an absolute top quality UV filter, that few problems will be encountered; there are situations where problems of flare will arise.
I seldom shoot directly into the sun, and if I do (sunset at early stages), then there will likely be lens flare in any event, and the filter may not contribute significantly to the effect.
I've always used a hood, and been aware that if light (particularly sunlight) falls directly on the front of the lens, then trouble will appear. If the hood isn't long enough, I frequently use my hand or a cap to shield the lens - this not always being possible (very shallow angles between sun and axis of sight).
Any dust on a lens or filter will magnify the problems if light falls on these elements - keep them spotless.
There are those that believe that any additional glass in front of the lens degrades the image quality - technically I would agree - but from a practical point, I'm not worried about it.
The Canon 24/105 zoom lens has 13 glass elements (the 17/55 has 19) - adding one more high quality piece of coated optical glass doesn't seem to me to be terribly significant - to some people it does - everyone does what one believes in.
As for "tack sharpness" issue, I suspect that if one did strictly controlled tests (and light on the front of the lens was eliminated), one couldn't tell the difference. It's far more likely that variables such as lens quality, the type of PP done, shutter speeds, f/stop, ISO, etc. would have more effect than a high quality filter.