P3D Re: "Bowl" distortion in viewers

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

> I'd like to hear if anyone else sees the bowl effect.

The great stereo legend, H. C. McKay, once said that "if you don't see it,
it's not there".  This was McKay's response to what he viewed as sterile
analysis and prediction of distortions in stereo images which (he felt)
could prevented people from taking pictures when the effect is barely
noticeable or not disturbing.

The funny thing is that this "bowl effect" (a.k.a. "Larry Berlin Illusion")
is not supported by theory.  In order to see a 3-dimensional distortion you
must have two slightly different images.  Assuming that the lenses are
nearly identical, why would the two images be different?  Any distortion
in one lens matches the distortion in the other, making this a 2-d effect. 
No matter how bad the lenses are, if they are identical then there is no
3-d distortion.  Small difference between lenses do exist (like a
difference in FL) buy they do not necessarily lead to fish-bowl distortion.

-- George Themelis

PS.  No, I have not seen it either!  It must be like these so-called
"stereograms".  Some people claim to have seen weird things by just 
gazing at them.  What nonsense!!!! :-)


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