P3D Re: VM Personal close up filters

[fj834@xxxxxxxxxxxxxxxxxxxxx (Dr. George A. Themelis)]

Linda writes:

>I haven't actually tried it, but one possible way to take closeup
>"hypostereos" is to take two separate closeup shots (with the Portra
>lenses) with a small camera shift between exposures (using a real or
>makeshift slidebar) and then mount the appropriate two of the four
>frames. This should also eliminate the "keystoning" distortion problem
>with the "angled-in" closups, I would think.

That's correct and people have tried it with the Realist and SLRs too.
There is only one problem.  You need to mask the images down to position
the correct stereo window.  This is no problem when I use my SLR and
mount the slides in 7p mounts (I have space to crop the 36 mm image to
the 28 mm wide mount).  Also, not a problem with the Realist if you have
close-up or half-frame mounts.  But with the VM I assume there will be a 
problem as the chips are placed in the reel with little room to move 
around.  The prismatic close-up lenses do not have this problem since
the function of the prism is to shift the image back in place.  But, as
you say, the price you pay is "keystoning" distortion.

-- George Themelis


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