Quote Originally Posted by pecama View Post
i have a quick question: building my smallest pinhole camera i found out a jet from a motorcycle carburetor that has a hole with a diameter of 0.98mm. The length is almost 1cm. Is this hole too long? Or can i use it with no problems?
Doesn't sound good. The ideal pinhole is a knife edge; a hole in an infinitesimally thick plate. Any length will constrict the width of the field of view. The ray tracing explanations in one of the posts above will illustrate why. Using what is in effect, a tube, most rays angled off the axis will be blocked.

DaveT