P3D Re: Pentax beam spitter: please describe

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>That's good to know, but does anyone have anything to
>report of the Pentax beam splitter? I get the impression that it's
>expensive, but could it then also be more capable (of satisfactory
>results)? I've been unable to get any info about the Pentax splitter from
>Pentax's web site, so I'm hoping that those of you out who own them might
>tell me a few things. How wide is the base? Is it adjustable? What is the
>filter thread size?

  The Pentax Stereo Adapter comes in 49 and
52mm thread sizes. You could use it on other
sized lenses with an adapter but may get
vignetting.

  It is designed to work with 50 or 55mm
lenses (on 35mm cameras) at a recommended
aperture of f5.6 or f8 as I recall.

  The mirrors are front surface but aren't
adjustable.

  B&H still lists it as a special order item
for about $300 or $350 as I recall.

  The current PSA is actually the PSA II
(model II). I have used both and actually like
the original PSA better. The II threads onto
your lens then has some rotational play built
in so that you can lever the adapter. But no
way to tighten it in place. So the adapter can
easily be bumped a bit an you can end up taking
photos with the PSA not level and get unviewable
slides.

  The original PSA has a metal band that goes
around a filter (or the front of the lens if
the correct size, which it is on Pentax 50's)
and then the band can be tightened up. Thus
the risk of having the PSA not level is reduced.

  All that said, I don't use mine much given that
I have Stereo Realist for 35mm and a Sputnik for
medium format stereo slide shooting.

Greg E.


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