----- Original Message ----- From: <photoe...@aol.com>
> I never heard of anyone using a slide projector to find the optimal pinhole > aperture. Somebody else out there might have heard about it. Slide projectors, enlargers and even scanners ( http://members.home.com/penate/diameter.htm ) have been used, NOT to find the optimal pinhole aperture, per se, but to simply find the diameter of the hole. > There are many formulas that various pinhole photographers have used. Many > have their own personal formula. All the formulas are in essence the same, all are of the form: Diameter = SQRT( Constant * light wavelength * focal length ) As for the Light wavelength, everybody uses "generally speaking" around 550 nanometers. The real and only difference would then be the value of the Constant. > Some pinhole photographers do not want the most optimal aperture. They > prefer a softer or blurred image. That's right, but to be 100% sure the pinhole you are using is not "optimum" (before any exposure is made) you'd have to measure the pinhole. Guillermo
