compensating zone plate

A question for all the mathematicians and physicists. Is it possible to
make a zone plate that compensates for fall-off. When one makes an
extremely wide angle shot the edges of the image are underexposed due to
the signifcant difference in the focal length from the center to the edges
of the film.

Is there a way of altering the line pattern and or line thickness of a
zone plate so that the edges of the picture get more illumination?

And just to make it interesting, if this is possible, is there a way of
calibrating or predicting the difference in exposure from one region of
the picture to another?

The things I end up talking about over lunch with another pinholer!

Gord
---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@duke.usask.ca 112 Science Place
http://duke.usask.ca/~holtsg University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
---------------------------------------------------------
Received on Tue Aug 21 01:19:52 2001