From: SFPhysics@aol.com
Date: Fri Dec 17 1999 - 07:47:48 PST
From: SFPhysics@aol.com Message-ID: <0.32ac93bf.258bb524@aol.com> Date: Fri, 17 Dec 1999 10:47:48 EST Subject: Re: 3D - Stereo Photography & Viewing
Subject: 3-D polarized slide show
From: "MC elover" <mcelover@yahoo.com>
Date: Thu, 16 Dec 1999 12:52:32 -0800 (PST)
hello pinholers and funkateers,
> the castro theatre recently showed Dial M for Murder
> in 3-D. according to a poster outside the theatre,
> hitchcock used 2 cameras to film the movie. then each
> of the two films was projected simultaneuously on the
> screen through orthagonal polarizing filters. the
> audience wore polarized 3-D glasses to make sure that
> each eye only saw one film, thus acheiving the desired
> stereoscopic effect.
> i was wondering if it would be possible to do the same
> thing with slides, using 2 slide projectors. has
> anyone tried this or seen it done? Also, if i send a
> beam of polarized light at a screen, will it come back
> polarized? if not, how did the hitchcock thing work?
> keep the funk alive
> --eric
Hi Eric and List:
As a card carrying union projectionist (had do something to augment the lousy
teacher salary), yes, you can use two projectors with polarized left and
right eye. In the 1950s there were cameras called StereoRealists,
Kodastereos, and others that shot the left and right frames simultaneously.
I have a StereoRealist and still do 3D photography. The projector itself is
really two projectors in one. From time to time eBay sells one for $$$.
There were also hand held viewers which are not too expensive, under $100.
One of many web sites exist for 3D at:
The screen ideally should be aluminized instead of the usual white. The
aluminum dust paint reflected back in a polarized manner much better than the
plain white. Problems occurred if the screen got dusty, the polarization
suffered. The filters on the projectors had to be adjusted closely and both
projectors had to be electrically linked with Selsyn motors so both would be
showing the same frame number simultaneously. Many 1950s films were shot in
3D, e.g., Monster from the Black Lagoon, It Came From Outer Space, etc., and
they were great fun. As an old fart I saw most of them as a kid at the El
Rey Theatre in SF.
For your use of 3D try this, use your camera to shoot a static scene then
move it about 4 inches to the right and shoot again. Try having objects in
the foreground about 3 to 5 feet close to the camera and the rest of the
scene more than 12 feet back. After development, place the two pictures on a
table and get a piece of cardboard over 18 inches long. Put one edge of the
cardboard between the two pictures and have the other edge up to your nose.
If you have properly placed the left picture on the left and vice versa the
right, you should be able to see a stereographic image. You may have to
cross and uncross yours eyes of find a way to allow each eye to center on the
photograph for that eye. Views have lenses that allow your eyes to more
naturally find the center. Make sure neither eye can see the other photo.
Hope you have fun with this,
Al Sefl
Projectionist out of work thanks to automation.......
SFUSD teacher at large thanks to bureaucracy......
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