Re: Zone Plate Focus stringency

>
> A zone plate focusses like a lens so you should adjust the focus for
> objects at different distances. On the other hand, they tend to have
> large f numbers (like f/32) so they have large depth of field. They
are
> also hard to focus because they are so dim.

I congratulate you folks who can focus one of these things through the
viewfinder. I pulled out my Crown Graphic, slapped on the reflex viewer,
tried focusing on a light source, tried focusing on a subject outside, and I
really couldn't tell any difference except at the extremes.

Maybe if I use a loupe. Maybe not.
Received on Mon Oct 29 12:48:55 2001