Karl wrote --
>hooroo Greg - maybe you have a local 'Lee' gel filter distributor >nearby, a theatre or lighting supply place should know. The stuff is >sold cheaply in thin sheet by the meter. I wouldn't ordinarily >recommend using a gel filter for taking pics but if you can mount it >flat and inside the camera instead of outside (to minimise reflections), >I shouldn't imagine you'd see much image degradation on a 4x5
I would not advise the use of inside, behind-the lens filters, specially for neophytes. It will result in out of focus negatives. l
Most photographers will never notice, and the rare few that do will attribute the degradation to the filter, but this is not the case.
Almost no one realizes that using a filter behind the lens throws
the image out of focus. When using behind-the-lens filters, focusing
the camera is nearly impossible with these in place, so people
"logically" focus, then insert the filter -- throwing the image out of focus -- and then make the exposure.
As Father Ansel clealy states in the Biblel...oops, I mean The Negative, one must compensate for this focus shift by focusing backwards 2/3 the thickness of the filter material. Who knows
how much that is ? Who can move the focusing knob precisely that
amount ? No one I know of. For all the trouble one goes to for sharpness with large format, I recommend keeping the filter up front,
and buying a decent shade for it.
--- Luis
