[photo-3d] Re:3-d lenses; prismatic?

[Alan Lewis <3-d@xxxxxxxx>]

Doug Wrote:
> 1. Do the lenses in a stereoscope /Holmes type viewer have to be 
> prismatic.  That is those in the two scopes I own are certainly wedge 
> shaped. Or is there some way to simply use +5 diopter eyeglass lenses?
> (I experimented a little with this but always saw to images.

Yes, they have to be prismatic when the image centerline separation
exceeds the typical human eye spacing of 2.5".

Yes you can use any conventional 5 diopter lens as long as you mount the
lens centerlines to be equal to or slightly greater than the image
separation.  This way you have in essence accomplished what the Holmes
prismatic half lenses are.  Holmes prismatic lenses are merely one round
lens cut in half and transposed left to right.  You can just use two
round lenses and mount with the centerlines approx. 3.5" apart. 
Eyeglass lenses should work too.
NOTE: You will end up with a large lens faceplate though if using round
lenses.

> 
> 2.  Has anyone out there had success building a stereoscope with good 
> quality lenses?
 
Yes. 

-- 
Alan Lewis  
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