P3D DVG effect

[koganlee@xxxxxxxxxxxxx]

Boris Starosta says:
"Here's how I think it works:  You are instructed to hold the pinholes
somewhat aside the center of vision from each eye.  This causes the rays
from the photo, which form the image that you examine, to pass through the
_edge_ of your eye's lens.  That is, the pinholes optically mask away most
of the lens of each eye, leaving you essentially (optically) with two
prisms in your eyes, which naturally cause a certain amount of chromatic
aberration.  This chromatic aberration, in opposite directions for each
eye, creates the illusion of stereo disparity, i.e. different depths for
different colors."

Not that it really makes any difference, but I believe that the effect is 
more likely from the bending of light rays at the inner edges of the 
pinholes (called diffraction) than it is from a prismatic effect of the 
lenses of the eye. (This is why pinhole images are kind of fuzzy, by the 
way, and why the smallest apertures, while giving the most depth of field, 
are not as sharp as moderate apertures.) Different wavelengths bend 
different amounts, hence the chromatic depth effect. 

David Lee



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