Re: front surface mirrors, distance

[P3D Ralph Johnston <copley@xxxxxxxxxxxx>]

Sixth problem is processing.  I took my film to CVS for prints and checked
the floppy disk option.  Two weeks later, back came prints of the left half
of each pair only .  The floppy had the same images.  Then I took in a
second roll and wrote on the envelope:  "print full frame".  Back it came
with "we don't print half frame prints".  Then I gave up.

I would try again with my 1-hour camera store processing, but now have have
twin XA-2's on the way from Rocky Mountain (using my cameras), as well as
an RBT X-4B in November.  The full-frame image will avoid all six problems
with the beam splitter.



>I have experience with the cheap mirror attachments, and they have a LOT
>of drawbacks.  First is attachment.  The Reel-3D version uses a plastic
>threaded ring.  Depending on how the threads mesh with the step-up or
>step-down ring (if you need one) and/or the filter threads on your lens,
>you may have a very difficult time getting and/or keeping the device
>level (horizontal) on the camera.  Given that it's plastic and there's
>some flex, it can pop off when the camera gets jostled in a crowd (this
>has happened several times to us).  A better-made unit with metal rings
>should eliminate that problem.
>
>Second problem is aperture.  Smaller apertures (which are desirable for
>maximum depth-of-field in stereo) will cause the black band between
>the images to be unacceptably large.  Thus you will have to limit yourself
>to no more than f/8 or preferably f/5.6, which will greatly limit your
>depth-of-field.
>
>Third problem is convergence.  While looking through the viewfinder
>and seeing the double image, you will have to adjust the mirrors to
>center your subject in both images.  This is notoriously hard to do,
>and there's only friction to keep the mirrors in place.  Add focusing
>and shutter speed to the equation and you will find yourself having
>to make three or four adjustments for practically every shot.
>
>Fourth problem is compositional.  These devices produce an image pair which
>is taller than it is wide.  This will restrict the range of subjects
>you can photograph without a lot of extraneous sky or ground etc.
>
>
>
>
>
>Fifth problem is resolution.  The second-surfaced mirrors noticeably
>soften the image.   If you enjoy really sharp pictures, you will not
>get them from one of these cheaper units.
>
>For not a lot more money you can get a stereo camera which will not
>have any of these built-in problems and will produce sharp, high-quality
>image pairs which can be projected, viewed or printed.
>
>	-Greg W.
>


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