Quote Originally Posted by will kirchoff View Post
Hello all-

I am building a 7 x 17 inch camera that I would like to create a zone plate for. There is a zone plate generator on the site Mr. Pinhole, but I do not know what I should enter as the proper focal length. Can anyone suggest a "normal' focal length for this size format? Thanks for any help- Will

Normal focal length for a 7X17" camera might be in the 450mm - 600mm range. However, many people prefer wide angle lenses for this format, and 305mm is very popular. Bear in mind that with a zone plate you have to be concerned about depth of field, since unlike a pinhole the zone plate lens focuses.

If I were you I would have the zone plate lens made in the 270mm to 350mm range.