Quote:
Originally Posted by dj_mocok
But as far as I know it takes a serious scratching for lens to be able to have difference in quality. The scratches on the filter are not deep ones, but more like tiny hair lines (not as thick as hair) due to (obviously) wiping the filter when there's some dust/particle on the surface. I don't know how many lines, but roughly maybe 7-8 tiny scrat
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Yes, I've seen plenty of used lens ads that say "small scratch or some dust particles ...won't affect quality" and they're probably right. But IMO, a few scratches on a filter or the lens' front element would do much more to diffuse light/reduce contrast, than a clean piece of coated optical glass (filter) over the lens. Each lens usually has 7, 8, 9, or 10 elements (pieces of glass) in them already, so how much can one more hurt? I read one article where someone said "it's like shooting through a window" ... it's not a window, it's a thin piece of precision, coated, optical glass made to be shot through. To be honest, I'm not seeing much of a difference at all between the test shots you did ... and that was with a scratched filter.
And yes I've heard that modern lenses don't need UV filtration, and that's probably true. As far as what would be considered "modern" ... your guess is as good as mine. I"ve also heard that modern lenses (and filters) are made with harder glass and some with scratch-resistant coatings, which is also probably true ... but coatings do wear off eventually ... a little bit every time you clean them. I always buy scratch-resistant coating for my eyeglasses and clean them carefully, but eventually noticeable swirls and scratches do appear. Again, that's why I'd rather be cleaning a filter all the time than the lens itself. My reason for using filters is not for UV protection, it's for damage protection. Every time I clean a filter instead of my front lens element makes me feel I've kept that lens pristine that much longer. When I'm in a wet, foggy, or sandy environment, I like the idea of the filter taking the hit, not my lens. And if and when that accidental bump happens, I feel better having that extra protection. And like I've said, the filter can be removed while shooting if you're truly concerned about a loss of quality .... but those test shots you did, with a scratched filter, convince me that any difference is minuscule. I took some shots of a friend's kittens last weekend, (see below)all with B+W filters left on to protect against nose prints, and I'm more than satisfied with the contrast. In fact, today's lenses are too sharp for most portraiture, so for portraits at least, some dust, a few scratches, or another piece of glass in front of the lens is actually preferable.
IMO, it really boils down to personal priorities and preferences. I'll stop beating this dead horse now.