In article <4vsf1g$r8v@hobbes.cc.uga.edu>, mcovingt@ai.uga.edu says...
[most deleted]
>I would like to hear from anyone who actually demonstrated a loss of
>image quality from a well-made multicoated UV or skylight filter.
>It's not enough to say that in theory there might be a loss. The
>question is, is it detectable?

In my experience, no (assuming a high-quality filter [uh, "Hoya"-level
is sufficient, I find.....]). Since long, fast lenses should show ill
effects of filters more than short, slow lenses, I tried a Nikkor 400mm
f3.5 EDIF with, and without (either of, or both) the front and rear UV
Nikkor filters. The differences in sharpness (if any) were less than
those introduced by minute mis-focus. I use UV filters on all my lenses
that will accept them, sharpness nut that I am....;-)
Hope This Helps