P3D Beamsplitter

[David Tiede <dtiede@xxxxxxxxxxx>]

I have a beamsplitter which has the name Prism Stereo that sounds like
the Delta beamsplitter description.  The beamsplitter consists of a
prism in front of the lens which is tilted a little and two front
surface mirrors which are likewise tilted a little relative to the
prism.  The combination of prism and mirrors rotates the two images such
that they are placed on the film head to head.  The single frame
containing both images is divided along the vertical much like
conventional mirror beamsplitters.  The images are wider than they are
tall.  There is a matching steal-the-light viewer to view the slides.
As the slide is inserted into the viewer there is an optimum depth of
insertion which corresponds to the images being aligned vertically.
There is a pin in the viewer which will mark the slide (cardboard mount)
such that a special punch can enlarge the hole.  The marking pin when
fully inserted is the same diameter as the punch hole.  Thus each slide
can be registered for correct placement.

I have taken a lot of slides over the years and have enjoyed the
attachment.  I have a lot of pictures of China and Mongolia taken when
the first Westerners were allowed back into the mainland.

I have not used the attachment in years because my latest camera has a
different sized lens which did not fit the adapter used to attach the
beamsplitter.  Like many such devices, the corners of the images would
become dark at large f-stops.

I recently purchased a Eumig dual projector system and plan to use it to
project slides taken with a Nimslo.  I will also experiment with cutting
a few of my old beamsplitter slides and mounting them in Nimslo size 2x2
mounts.


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