On Tue, 1 Dec 1998 02:47:00 -0800, Andreas.Nicklass@usa.net (Andreas Nicklass) wrote:
>Finnegan T. Tsai wrote:

>> >I've tried that not too long ago, taking two shots of the same scenes
>> >with identical settings with UV on and off. I did notice pics with UV
>> >filter showed slight loss in sharpness. However, the differneces are
>> >hardly noticeable at lower focal lengths, with telephotos being
>> >affected more. In fact, at lower focal lenths (~<100mm), I could
>> >barely tell the difference, and I had to look VERY hard to find
>> >something. This is a personal observation, and not a scientific study.

>That's exactly what I heard from somebody else. 'Optically neutral'
>filters aren't at all neutral in front of long focal length lenses.

>> Sounds like light loss to me. For long telephoto lenses, the light has
>> to travel through many thick glass elements. The energy loss will
>> bring sharpness degradation. Try those multi coating filters
>> by Hoya and B+W. Maybe the side effect will go away.

>At least for the case I mentioned I know that the experience stems
>from usage of B+W and Heliopan filters - not exactly the cheap
>stuff. The difference was observed between images with and w/o
>filter with exactly the same lens.

OK, to check this out, I set up a Nikkor 400mm f3.5 lens (rather
sharp wide open...) on a tripod and shot detailed targets about
two miles away. I tried shooting the same field area (lens wide
open) with no filters, rear (Nikkor) filter only, front (Nikkor)
filter only, and both filters on the lens.
Guess what? There was no difference that could be attributed to
using a UV filter (or even two...) or not... (other than focus
shift when the rear filter was removed).