P3D Re: miniaturization & cross-viewing

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Mark Shields <beamsplitter@xxxxxxxx>


>Stereo projection as it is usually practiced requires:
>
>-an expensive, large, heavy projector with polarizers

Only if you insist on using Realist mounts.  A pair of
commonly-available Ektagraphic Carousel projectors are also suitable.

>-glasses
>-a silver screen


Yes, these are both required for polarized projection.  With anaglyph
projection, glasses are still required, but only one projector and any
suitable screen.

>-a very dark room, because the images are not very bright


If you use antique equipment you are somewhat limited in choice of
projection lens focal length and bulb wattage.  With modern equipment,
you can fill an auditorium-sized screen or a 50" home screen with the
same projector (using zoom lenses, for example).  Also, high-brightness
light modules are available for Ektagraphics (although at a premium
price).

>As for which is easier, parallel or cross-eyed, I find
>cross-eyed easier.

I can do either, but prefer parallel, because it involves *relaxing* the
eye muscles, rather than *tensioning* them to converge.  For extended
viewing, parallel is definitely my preference.

Another thing to consider about your "dual-image" projection idea: the
resulting image size will be tiny compared to polarized projection,
because in polarized projection both images are projected into the same
area and overlap completely.  In keeping them separate, you will have to
fit both images onto the screen side-by-side, reducing width and height
by 2, so the resulting single image will be 1/4th the size of an
overlapped, polarized image.

     -Greg W. (gjw@xxxxxxxxxx)