If you have a look at my post in the pinhole forum (bottom of the first page of posts) titled "Zero Image" there is a photo on the second page of posts that gives an idea... The Zero Image camera has three x 25mm extensions (the base and two extras) that give 25mm, 50mm, and 75mm rough equivalents in 35mm... There was a post somewhere here by a guy in Holland (I think) who had worked out a process to reduce the vignetting during printing but I can't find the post. He has some very good images and examples of the distortions and effects that can be had with a pinhole camera.