----- Original Message ----- From: "Guillermo" <pen...@rogers.com> > > I gather that by "aperture of the zone plate" you mean the size of each of > the rings. Mr.Pinhole formula is what the scientific community uses for > their high-tech uses of zone plates and my non-scientific tests (focusing > aerial images produced by zoneplates) have confirmed that. Other use > slightly different formulas.
I was reading my own post and it seems not to be too clear. What I meant was that when I mount zone plates on my 4x5 view camera and focus on the aerial image until it is a "sharp" as they would be, the distance zone plate to film plane matches very closely with what the formula Radius = SQRT(wave length x focal length x ring#) would predict. Now, the formula can also be written as Diameter = 2 x SQRT(wave length x focal length x ring#). Some people use formulas slightly diferent, what they change is that number "2", Patton for instance, uses 1.86 http://www.stanford.edu/~cpatton/zoneplatemath.htm Guillermo
