P3D Re: boris starosta's site

[bercov@xxxxxxxxxxx (John Bercovitz)]

Larry B writes:

> I agree with both you and Dr. T. However, I'll point out that for
> Macros done at a distance of 12 inches or less from the lenses, the
> resulting images wouldn't even have the same subject matter in them unless
> you were technically set up to take a HYPO picture. If you aimed at the same
> subject matter from the technically Ortho stereo base of the interocular
> distance you would have to rotate the cameras and create other distortions
> just to get the same subject matter. 

I don't think I've done shots at 12" with a normal base but I have done
some at 40" with a 190 mm base and I have done some at 18" with a 67 mm
base.  There's plenty of overlap if you're using a 35 mm SLR and a slide
bar (no dastardly toe-in) and a 5P mount.  These shots were with a 50 mm
lens, which matches my Star D (Brumberger?).  So my guess is that you can
do macros at 12" without doing hypos.  Of course this says nothing about 
violations of maximum on-film deviation!  Maybe I should do a quick calc...

Yes, with 50 mm lenses, 24x36 standard SLR frame, and 67 mm sterobase, if 
you use standard 5P mounts (21.5 width), you will get full coverage at 231
mm distance which is about 9".  Would a sketch help?  I could make a GIF.
If you use a 35 mm lens on your SLR, one would be able to get closer, but
I personally don't have a viewer to match that focal length.

John B


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