ASPECT RATIO

[Paul S. Boyer <boyer@xxxxxxxxxxxxx>]

ASPECT RATIO
   Stephen Kearney <neff123@xxxxxxxxxxxxxxxxxxx> wrote earlier to
discuss the aspect ratio or stereograms.  His preference was for a
wider aspect ratio, which, he pointed out, accords better with the
shape of our visual filed than does the almost-square Realist format.
   There seems to be a general preference for a wider aspect ratio
for stereograms, but I think that it is in order to understand how we
arrived at the Realist format.  It was not just to keep down film
costs, although that was a consideration.  The designers of the
Realist system knew that, although the human visual field is wider
than high, the area of stereopsis is roughly equant!  In this sense,
the Realist format fits.
   What I would myself propose (and advocate) is that we stick to
Realist format, or European 7-perforation format, and mount in
standard Realist mounts so that the formats can be shown mixed in
projection.  Take all the 24 by 36 mm pairs you wish, but mount them
as Euro pairs so that they fit the commonest projectors and viewers.

   Another interesting bit of history: an early Dutch expert on
stereopsis  (Albada) was bothered by the restriction of the stereo
window, and experimented with stereograms made with very wide-angle
lenses.  The viewer also had to have lenses of ther same, very short
focal-length.  The intended effect was to eliminate the stereo
window.  I have never seen his results.  Perhaps someone out there
knows if they were preserved.  I do remember reading that the result
was very good, but I can see some problems:
   1) Albada used large-format film.  If one spreads all the
information from the total field of view onto one little 35-mm slide,
one might run into a problem of insufficient resolution in the film.
   2) There is a likelihood of distortion due to the very short
focal-length lenses.
   3) The lenses are probably expensive.

   Perhaps details are in Albada's magnum opus, ALBADA, L. E. W. van,
1931.  Stereophotographie, in Handbuch der wissenschaftlichen und
angewandten Photographie, Band 6, Erster Teil, 1-101.  Verlag Julius
Springer, Vienna.  (I can't find my copy just now!)
--Paul S. Boyer   <boyer@xxxxxxxxxxxxx>


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