Re: focusing zoneplates

--- "Gordon J. Holtslander" <holtsg@duke.usask.ca> wrote:
> I'm going to try making some zoneplates. I've read about that zoneplates
> require focussing. None of my cameras pinhole cameras can focus. Is
> zoneplate focusing necessary in all cases? Is focusing needed only for
> subjects that are close to the camera?
>
> Does it matter whether a positive or negative image of the zone plate is
> used? Does the center circle have to be opauque?

Gordon -

Like a pinhole, the Zone Plate would be created for a specific focal length.

The center does need to be opaque, which then dictates the clear/opaque areas
of the surrounding rings.

You can reference the excellent article, The Zone Plate by Chris Patton, at
http://members.home.net/hmpi/Pinhole/Articles/PinholeArticles.htm for more
information.

Cheers -

george

=====
Handmade Photographic Images
http://members.home.net/hmpi/

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Received on Fri Jan 4 06:39:21 2002