Re: Taylor-Merchant stereoscope lenses

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxxxx>]

At 4:07 AM 8/8/96, P3D John Bercovitz wrote:

>Yeah, polycarbonate has about a 5% higher index than crown but I
>bet the Abbe number is the pits (for single lens use) as you say.
>Not as good as some acrylics, though a much tougher material.
>Also, it's more expensive than acrylic.  May be tougher to mold, I
>don't know.  Not sure anyone would make a stereoscope lens out of
>it.  Well, with the higher index you could use a little less of it
>- that would save some money.
>

Oh, I definitely wouldn't recommend that, unless you wanted to
build the first bullet-proof stereoscope.  I actually let my
optician talk me into trying a pair of polycarb lenses (on a
free trial basis) & gave up on them after a week.  Not only were
the aberrations horrendous, the resolution fell off very quickly
towards the edges;  I had less than a 30x30 deg field of sharp
vision.

-Jim C.


------------------------------------------------
Jim Crowell
School of Optometry
360 Minor Hall
University of California
Berkeley, CA 94720-2020
(510) 642-7679
jim@xxxxxxxxxxxxxxxxx
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