RE: [Leica] Lense testing...

["Austin Franklin" <austin@darkroom.com>]

> My problem with a lot of this testing is that it only measures
> the effect of
> one variable - in your case, the effect of your filter on your lens, using
> your camera and your film, etc. I think what needs to be done, is
> that once
> you have somehow determined a difference between filter and no filter, you
> need to place that in the context of all the other variables
> present when a
> photograph is taken.

The tests do not include camera or film.  This is an optical bench test of
the effect a UV filter will have only.  It will show what the degradation in
resolution and contrast are.  That is it.  Then that needs to be translated
into the real effect it MAY have on the film, and then on the resultant
reproduced image (print, projection etc.).

> Between the photographer's eye and the finished image, there are too many
> variables to isolate a single one and evaluate it all by itself.

And that is why I am only testing ONE aspect, and only one.  A key in
testing is to isolate your variables, and only test one thing at a time.
That way you are most assured that the effect you are seeing is caused by
only that one thing.