Mailinglist Archives:
Infrared
Panorama
Photo-3D
Tech-3D
Sell-3D
MF3D
|
|
Notice |
This mailinglist archive is frozen since May 2001, i.e. it will stay online but will not be updated.
|
|
Re: Taylor-Merchant stereoscope lenses
- From: P3D John Bercovitz <bercov@xxxxxxxxxx>
- Subject: Re: Taylor-Merchant stereoscope lenses
- Date: Tue, 6 Aug 1996 18:37:32 -0700
OK, I looked it up. The lowest dispersion common optical plastic
has a substantially lower Abbe number than the commonly-used BK7
optical glass although their refractive indices are similar, which
surprised me. I thought plastic had a lower refractive index.
Well, maybe non-optical plastics do. Of course you can't get a
really high refractive index plastic that I know of. So it would
be tough to make an achromat. For low dispersion you want a high
Abbe number so glass wins easily. On the other hand, I didn't
check window glass and maybe I should. Who knows how cheap a lens
manufacturer might go? 8-)
I just noticed you meant an achromatic glass doublet vs plastic. No
comparison there. I don't know how good an all-plastic achromat would
be. That could be a tough critter to build and get decent results.
Might work. Could be very cheap in quantity.
John B
------------------------------
|