new stereo camera design

[T3D Peter Abrahams <telscope@xxxxxxxxxx>]

>most importantly, 
>suggestions for an optical path which images an erect image onto the film,
>not an inverted one as is standard practice.  This, you will find, is a 
>very important factor in this new camera design!

Image erecting systems have been used for over two centuries, and there are
many variations.  All of the lens erecting systems that I am aware of
suffer from several problems:
--they significantly increase focal length, making the instrument less compact
--they add unacceptably high levels of curvature of the field, and
spherical aberration or astigmatism as well.

Prism erecting systems are free of aberrations when used with parallel
rays, but add some (much less than lenses) when used with converging rays.
They add greatly to the bulk of the instrument.  With a stereo camera, they
would allow the use of adjacent film 'chips' on the 35mm strip, even though
the lenses are spaced a distance apart.

Is it possible to inform the list as to why one would want to erect the
image on the film?  The aberrations to be overcome, the expense of the
extra elements, the added bulk, and the typical (problem-free) use of
inverted images, would indicate that an erect image stereo camera would
need a significant justification for production.

Finally, you might have reasons to wish the discussion on the new camera to
be private, or as private as e-mail can be, but I believe the subject is
very appropriate to tech3d.

Peter Abrahams  


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End of TECH-3D Digest 140
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