On Tue, 13 Aug 2002 18:05:21 GMT, "Al Denelsbeck" wrote:

> As others have said, the most noticeable negative affect is in situation
>where flare is a concern.
>
> However, magnification makes a big difference too. When using a long
>lens, or with macro work, a filter may have much more noticeable
>degradation. I discovered this with my 170-500mm, and that quite expensive
>filter is now permanently removed.
> - Al.

I have rarely noticed a problem from flare with UVs used.
Also, to test the filter-vs.-no-filter resolution, I set
up a 400mm f3.5 Nikkor (quite good, even wide open) and
checked the image on film shot with/without the rear and
front UV filters (in the 4 possible variations), and could
detect no resolution differences with a good 10X magnifier.
Since a long, fast lens is likely to show any differences
more than a short, slow lens, I'm satisfied that a good
filter has no noticeable effect on resolution, and I
continue to use them...