Re: Requirements for a new stereo camera

[bercov@xxxxxxxxxxx (John Bercovitz)]

In the concrete proposal to manufacturers, I would push for longer 
focal length camera lenses for two reasons.  1) The hand-held 
viewers have never been able to deliver the promised wide angle of 
either the Realist or the Euro cameras.  2) In projection, the 
ortho seat is, as stated in the proposal, at the front of the 
audience (if you're lucky) so let's move that ortho seat back to 
where it ought to be.  I would also say that the upscale version 
of the camera should have interchangeable _fixed_ lens sets so 
that the die-hard wide-angle fan won't be shortchanged.  To 
accompany a short lens set for the camera, a short focal length 
(read very very expensive) hand-held viewer should be offered.  

Ferwerda says that the camera lenses should be about 70 mm in 
focal length if the intended viewing method is projection.  
Presently stereo camera lenses are half that.  So let's split the 
difference and use 50 mm (50/35=70/50).  I would put the lenses 
67 mm on center and the film gates 69.25 mm on center for a 1.5 m 
built-in window and a 33 mm film gate width.  If the finished 
slide has 32 mm apertures, the width of the field of view is 35.5 
degrees as opposed to the 34.0 degrees of the Realist format.  In 
addition, because of the scale laws and certain fixed parameters 
(the scale of humans for instance), this system would be viewable 
at ortho focal length in a hand-held viewer.  Also, Kodachrome 64, 
of marginal resolution in the Realist format, would have great 
resolution with the longer focal length and I could stop using 
Kodachrome 25.  8-)  (The answer to lack of film resolution is to 
use more film area which means using a longer focal length.)

The downside of this format is that although it gives you the wide 
field of view the Realist was intended to give (but never gave), 
it does not give you the height the Realist format was intended to 
give (but never gave), so unless your portraits are of people in 
repose, this new format won't work any better in portrait than the 
Realist or Euro formats do as they are presently implemented.

I think more than one standard slide mount should be offered.  
There is no reason whatsoever that film chips from this camera 
should not be mounted in Realist format mounts so as to be 
viewable in an existing, unmodified hand-held viewer or viewable 
on a square screen projected with a Realist-format-only projector.  
To this end, Realist format guidelines should be in the camera's 
viewer.  If the camera's viewer is in stereo, the depth of these 
guidelines should be at 2 m to match the current mounts.  
Likewise, and for the same reasons, there is no reason not to 
mount these chips in a Euro mount.  In addition, the Euro mount 
would serve as a good closeup mount for those who mount closeups 
to the window (almost everyone).

Lastly, wider projection screens are available but they should be 
made more available to make for easy projection of this format.

John B


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