Re: Stereo Difficulty

[P3D Paul Talbot <ptww@xxxxxxxxx>]

DrT continues to ponder the reasons for varying excitement levels
among viewers of stereo photos:

> 90% is still a large proportion of the population.
> The question that is still unanswered in my mind is why do some of
> this 90% has such diverse reactions when exposed to stereo.  Some
> people go bananas, others are totally indifferent (even though they
> enjoy a healthy stereopsis).  We have examples of couples where one
> spouse is in love with stereo while the other, even though is also
> interested in photography, has no interest in stereo photography.

Herbert McKay has some interesting comments on the topic.  He writes:
"Stereoscopic perception is a characteristic of marked variability...
Some people have such a marked stereoscopic sense that they are always
painfully aware of the flatness of the ordinary photograph; there are
others [who rely on non-stereoscopic clues to such an extent that they]
see depth in a good planar photograph...Such people see nothing unusual
when viewing their first stereogram...

McKay also reports that the consensus of eye professionsals surveyed
was that: "about 1/3 of all adults have low stereoscopic perception,
and of the remaining 2/3, from 12 to 15 percent have fully developed
stereopsis."  Also, "those who practice stereoscopic photography are
usually in the high bracket..."

It may be a good idea to think of stereoscopic perception as a
continuum, rather than a clearly defined "yes" or "no."

Paul Talbot


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