Another way to think about it is that the "ideal" pinhole size really only applies at the center of the image. If you curve the film plane along one axis to maintain a constant distance from the centerline of the film to the pinhole, then the pinhole can be the "ideal" size along the centerline. Making the hole bigger will just make it less sharp. If you really wanted the sharpest, most even exposure, then maybe a spherical film plane would be the answer......I'm not sure how that would work though! (or how you'd print it).
Originally Posted by Vaughn