----- Original Message ----- From: Chris Peregoy <pere...@gl.umbc.edu> To: <pinhole-discussion@p at ???????> Sent: Monday, October 29, 2001 12:14 PM Subject: Re: [pinhole-discussion] Zone Plate Focus stringency
> Guillermo wrote: > > >Although I do not recommend focusing of the zoneplate every time you make an > >exposure, I do recommend you focus it ONCE so you find out (if you wish) the > >actual focal length of it. To do it, aim your camera to a light source > >(light bulb for instance) or well illuminated object and focus on the aerial > >image, rather than on the ground glass. You will be surprised how "good" is > >the image a ZP produces. And yes, use a loupe. > > > >Guillermo > > > > > > > > What do you mean by "aerial image" That was going to be my question.
