I have started a 8 inch lenseless schmidtt camera based on an article by Peter Ramberg in S & T a couple of years ago. Its a 8 inch f3 spherical mirror with a baffle at the radius of curvature to reduce the f ratio to f4.5 to 5 to control spherical aberration and still be fast enough to take photos with relatively short exposures. Apparently this is the optimum trade off between speed, spherical abberation and curved focal plane.
I've got the mirror ready to figure and would welcome any comments from anyone that has any experience with the set up or general comments on the concept before I get too far.
Thanx in advance
Mark Bolton