Quote Originally Posted by Toffle View Post
The best part is, I eye-balled a pinhole of .3mm, then took my camera up to the lab, where they put it under a microscope and measured.... .3mm
The optimal pinhole diameter for a focal length of 40 mm is roughly 0.23 mm. So, 0.3 mm is a bit on the larger order, but it will work fine. Most people shoot pinholes for their unique characteristics and not to get optimal sharpness results.

Good luck and don't forget to post some images.