[LargeFormat] Zone Plates

[Douglas Cooper]

> 
> At the other end of the spectrum is the zone plate.  From  "pinhole
> Photographery Rediscovering a Historic Technique":
> 
> A zone plate diffract light, consequently zone plates are closely
> related to pinhole photography. Zone plate render soft-focus imgagery,
> yet they are not like soft-focus lens imagery. The beauty within a zone
> plate image is the recognizable halo or glow that surrounds any strong
> contrast edge. this glow occurs becuase light rays are considerably bent
> when hitting the edges of the opaque ring within the zone plate*.
> Foliage such as green leaves under certain lighting conditions may
> resemble infrared imagery.
> 
> a zone plate is made of concentric rings about a clear aperture. (think
> tiny target) The entire plate (hole) is usually less the 1/8" dia and
> made of tech pan or lith film backed by a brass shim.
> 


Are these zone plates expensive?  And how do they attach?  (I still don't
have much of a sense of where they fit on the lens/camera.)
 

Douglas Cooper
http://www.dysmedia.com