Re: stereo microscopes

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Thu, 30 May 1996 21:07:31 -0500
>From: P3D Neil Harrington  <nharrington@xxxxxxxxxxxxx>
>Subject: Re: PHOTO-3D digest 1355

>William Carter writes:

>>I will agree that Wheatstone may have been the first to make drawings in 
>>3-D (His first appeared in 1838). But, the argument that "One could not 
>>have a better "proof" or demonstration of stereopsis" does not apply. I 
>>think the 1677 invention of a stereo microscope is a far more palpable 
>>demonstration of proof. 

>Maybe I missed something, but the original mention of this 1677 microscope
>described it, I thought, as a BINOCULAR microscope.  Is there any real
>evidence that the inventor had stereo microscopy in mind when he designed
>it?  I don't pretend to have an expert knowledge of microscopes, but I
>believe the modern dual-eyepiece, single-objective microscopes are not 3-D
>instruments at all, but simply present the same image (via a beamsplitter,
>presumably) to both eyes, the object being to allow the microscopist the
>greater comfort of using both eyes rather than one.  

There are 2-objective, true stereo microscopes these days, and there are
1-objective, non-stereo binocular microscopes, but I think there may
also be some 1-objective, true stereo models (not sure that's the same
principle as WC has previously described). Anyone have an Edmund Scientific
catalog handy?

>It seems to me it would be awfully hard to make a real 3-D microscope with
>17th-century technology, chiefly because of the difficulty (if not
>impossibility) of getting the objective lenses close enough together for
>that purpose--unless we are talking about a VERY low-powered microscope.

Many (perhaps most) of the current stereo microscopes are very low 
magnification compared with most non-stereo microscopes. High power
stereo microscopy using conventional techniques appears to be very tricky
(or at least very expensive :-).

John R


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