Has anyone built a LF pinhole? I have some film that is 10.5in x 120ft. I am thinking of building a 10.5x18 inch camera. My question is should I make it so the film plane at the same distance from the pinhole on a circle or flat like it would be in a normal camera. When I 've used shorter length, ~300mm, pinhole on my 8x10 the edges seem to get distorted. Was this a function of a badly made pinhole?