Re: PHOTO-3D digest 1358

[P3D Neil Harrington <nharrington@xxxxxxxxxxxxx>]

>>Maybe I missed something, but the original mention of this 1677 microscope
Date: Fri, 31 May 1996 11:26:51 -0500
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>>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?

I just got their latest catalog a few days ago.  It doesn't show any
dual-eyepiece, single-objective microscopes, though I know they exist.
Edmund does have some low-powered stereo microscopes with two (or more,
turret-mounted) objectives.  It's hard for me to see how there could be a
single-objective stereo microscope.  I suppose there might be a diaphragm
with two apertures in or behind the lens, but that seems like it would be a
fiendishly hard thing to make work.

>>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. 

Yep.  Edmund's are typically 20X, though one model does go as high as 40X.
Even with such low power, it's apparent from the illustrations that they
have to use some sort of prism arrangement to get the objectives close
enough together.  I'm sure no one did that in the 17th century!




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