Re: Franka Beam Splitter

[michaelk@xxxxxxxxxxx (Michael Kersenbrock)]

>>Still like "real" stereos better ('cept when I need a fast shutter).
>
>Editorial comments aside :-), if your camera has a horizontal-travel
>focal plane shutter, then when you use a beamsplitter the
>synchronization
>between the left and right views will be only a little better than 1/2
>of the X-Sync speed.

I assume that "half the speed" means the "twice as fast as" sort of
interpretation seeing as how a horizontal curtain has half-a-full-35mm-image 
distance to travel between the "same points" in each image.

I wonder if having out-of-sync but sharp is better or worse than in-sync-
but-fuzzy?   I expect that the direction of movement vs. direction of the
curtain would make a difference in quality as well.  

>This does not apply if you use a flash in dim lighting conditions, or if
>you have some other kind of shutter. And of course it's not a problem at all

Yes, fortunately, I use my Pentax beamsplitter on a Pentax camera that
has a vertical running focal plane shutter, so my 1/2000 sec. beamsplit
shots maintain stereo synchronization.

>This does not apply if you use a flash in dim lighting conditions, or if

If one is using a flash, then the advantage of the beamsplitter itself
dims.  The effective shutter speed then is that of the flash's duration.
Flash photography using a realist-format camera works quite well and using
the beamsplitter, in my experience, yields no advantage.

>you have some other kind of shutter. And of course it's not a problem at all
>unless you're trying to photograph something that's moving rapidly.

Quite true as well.  Another reason for the fast shutter isn't just to
stop the subject, but to sharpen the image due to camera jitter when
being held by someone who's in a hurry for opportunistic shooting w/o
a tripod or other suitable support available in the split second used
to prepare for the shot.  :-)


>John R

Mike K.


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