P3D Cardboard cutout effect

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Very interesting suggestion by spacey@xxxxxxxxxxxxx (Dylan The Hippy
Wabbit) regarding the cause for cardboarding:

>So after a lifetime of seeing flat photos and drawings which looked just
>that, it could easily be that cardboarding is an attempt to reconcile
>seeing depth in a flat picture.

(For the benefit of beginners: cardboarding or "cardboard cutout effect" is
the impression that objects in stereo pictures look like cardboard cutouts,
instead of real objects) 

This is something that is certainly a problem with beginners.  Just other
day a friend asked me about the stereo pictures in the "Hollywood 3D" book.
He thought most people in the pictures looked like cardboard cutouts.
I remember my first stereo Realist picture... I took a picture of my wife
in front of our apartment building.  When I first looked at it I got the 
very strong impression that she was a cardboard cutout.  Now I can look 
at the same picture and don't see any cardboarding at all.

It seems that cardboarding is most noticeable with pictures of people which
supports the notion that psychological causes play a major roll here.

Lets say that a person is 10 feet away and facing the camera.  Why do we
expect to see depth within this person?  How much depth range is within the
person? Can that be resolved?  In real life we expect the person to move,
we are moving (motion parallax is a very strong depth cue).  It the stereo
picture nothing is moving.  Hence the "cardboard cutout" impression.

Being used to the effect is also a factor.  Experienced
viewers are not only familiar with stereo images but are also used to any
abnormalities or distortions associated with them (as in the "stretch"
which bothered me greatly at first but don't see it any more).

-- George Themelis


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