P3D Homemade Beamsplitter

["Jeff Toman" <jtoman@xxxxxxxxxxxxxxxx>]

Since subscribing to the photo-3d mailing list earlier this year, I have
really been amazed at all of the creative ideas out there for capturing
photographic memories in stereo.  We are not afraid to take things apart,
try different combinations, and "rig" things up.  Although not every idea
works for all situations, if you dream it, you can do it (or you can do
something close to it) provided that you put forth brainpower and elbow
grease.

I had been a 2d photographer for several years, but when I learned how to
take pictures in 3d (still-lifes, single camera) about 5 years ago, a whole
new world was opened to me.  Since that time, I have tried to improve the
photos I take.  At first, all I could do was cross-eye viewing, and only
about 50% of the people to whom I showed my photos could actually cross
their eyes to see the effect.  Cheap plastic stereoscopes from Reel3D solved
that.  Then I rigged two cheap fixed-focus cameras together with a
synchronized cable release because I wanted to freeze action shots as well.
Unfortunately, the lenses weren't very good, it cost twice as much to
develop (since there were now two rolls instead of one), and the lab could
never seem to get the color density to match between the rolls.  Since at
this time I am primarily interested in shooting negatives for 3D prints to
be viewed in a stereoscope, I decided to build my own beamsplitter device to
use on my Minolta SLR.  This way, I can shoot both 2d and 3d photos on the
same roll.  Also, I would not need to mount the halves of the stereo pairs
together.  They would come ready to view.  In fact, a 4X6 print would allow
a 3" width for each half of the pair.  I know that Pentax and Franka
splitters are floating around out there, but I wanted to see if I could make
one to my own design and specifications.  The end result is rather bulky and
heavy, and not quite as streamlined as the production beamsplitters, but it
looks like it will work well.  The pictures were easy to compose through the
viewfinder because I can look directly through the lens and see each half of
the stereo pair in front of me.   I took some pictures last weekend in
Washington, D.C., but they are not developed yet.
I am eager to see the final result.  Because of the size of the prisms (from
Edmund Scientific) that I had to use in order to achieve a large enough
image size (both halves) to completely span across a 35mm negative, the
splitter is hyperstereo, with a base of 112mm.  Using my 50mm focal length
lens, my near subject must be several feet away (approx. 11) by the 1 in 30
rule.  Nevertheless, the composition is not a problem.

I look forward to hearing more of everyone's creative ideas.

Jeff Toman
jtoman@xxxxxxxxxxxxxxxx