Why three or more images for a lenticular?

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

To those of you who are lenticularly knowlegable, perhaps you could answer
a question.

As we all know, stereopsis is quite effective with only two images when
taken with an appropriate stereo base.

Why, then, do lenticular cameras like the Nimslo, Nishika, Image Tech,
etc. have three, four, or even more lenses?

Is the very close spacing a compromise to keep these cameras relatively
compact and sparing of film, and is this compromise perhaps responsible
for the apparent lack of depth in consumer lenticular prints?

I know from experiments with my Nishika that the inner pair show almost
no depth, and even the outter pair are somewhat hypostereo when viewed
in a stereo viewer.  How can they possibly contribute any depth when
processed into a lenticular print?

        -Greg W.


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