[photo-3d] viewer optics

[Peter Abrahams <telscope@xxxxxxxxxx>]

>If I buy a pair of "modern" achromats from Edmund Scientific... would 
>these problems be absent?

A standard achromat from Edmund is not designed for viewing slides -
although they work, like any magnifier would work.  To see what a stereo
viewer should be, compare a good 35mm slide viewer.  To see how good a
stereo viewer could be at high cost, check out an modern, expensive 35mm
slide viewer -- they are absolutely sharp across the field, with very
little or no distortion, and have decent eye relief.

>I was under the impression that achromatic lenses have zero eye relief,
meaning 
>that the minute you start moving the eye away from the lens, you see less
and less.  

No, those are unrelated qualities.  Eye relief can be designed into an
eyepiece, though it necessitates a large diameter and is expensive.  If you
don't view while wearing spectacles, only a small amount of eye relief is
needed.

>I use them for wide RBT slides and I don't see these problems... sorry...

Compare the Red Button to the deWijs, or to a good mono slide viewer; I
think the problems would be apparent.  But as I said, I use a Red Button &
it is the best viewer I've used; however the eyepieces are nowhere near as
good as 1950s, inexpensive technology would have permitted.

_______________________________________
Peter Abrahams   telscope@xxxxxxxxxx   The history of the telescope & 
   the binocular:   http://www.europa.com/~telscope/binotele.htm

 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/