Re: [photo-3d] Re: [3Dsalon] Misalignments & stereo projection

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

----- Original Message -----
From: <Project3D@xxxxxxx>
To: <photo-3d@xxxxxxxxxxxxxxx>
Sent: Saturday, March 31, 2001 1:47 PM
Subject: Re: [photo-3d] Re: [3Dsalon] Misalignments & stereo projection

> ...A slick projectionist can alleviate the
> pain of the audience by rapidly setting the vertical alignment...

Alleviate, but not eliminate.  The instant a misaligned pair hits the
screen, it is instant headache time for many people.

The thought occurred to me, that a stereo projector with a "preview"
capability would be very nice.  I have a pair of (very) old Bell & Howell
"automatic"  2 x2 slide projectors that have a small built in preview
screen, and I have seen others.

One basic design that could work for stereo projectors is the swinging
mirror type.  When the slide carrier shutter closes to change to the next
slide, a mirror swings into the light path deflecting the image to a small
screen on the side of the projector, that the projectionist can view.  A
diopter correction lens also flips into place, so that the small image will
be in focus without having to change the focus of the prime projection
lenses.

Once the projectionist is satisfied that the image is aligned, he/she
presses a button that deflects the image back to the main screen.  I would
think that someone handy with building simple mechanical devices could even
make an external box that would fit in front of an existing stereo projector
that would perform this function.  If the mirror were hinged to flip out of
the way, nothing would be in the light path to degrade the large screen
projected image.

JR


 

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