Re: 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"

-- 
Chris Peregoy | http://www.gl.umbc.edu/~peregoy | http://imda.umbc.edu/