Re: [photo-3d] Re: To math or not to math?

["Dr. George A. Themelis" <drt-3d@xxxxxxx>]

Mike, a.k.a. "math guy", wrote:

>I do not bracket base 
>separation because I'm able to measure near and far point distances 
>quite accurately [...]

>My calculator tells me what base separation to use to achieve the 
>precise on-film deviation that I have chosen [...]

Very good... I am now reminded of some spectacular
live head-only portraits taken with a Stereo Realist.  
This was done back in the 1960s and the collection
of stereo slides is available for loan and study from PSA.  

The photographer put the Stereo Realist on a slide bar and 
took two pictures by shifting the camera in-between, to
reduce the stereo base.  The camera was equipped
with close up lenses.  The model was a sailor with 
a pipe in his mouth.  The result was IMO excellent!

The reason I bring this up is that I have hard time
figuring out what "precise on-film deviation" is
required for this shot.  In particular, by slightly
changing the pose, the distance between the nose (or
pipe) and the ears (which are the near and far points
in this scene) can change drastically.  Does that
mean that the stereo base should change too, even
though it is really the same subject being photographed?

This is just one example that in my mind puts into
question the notion that the stereo base depends
on the distances of near and far point distances,
without any consideration given to the subject being
photographed.  So, what good is the powerful calculator
if the assumptions behind the calculations are in
question?  Hence, bracketing might be required for
the stereo base too.

George Themelis

 

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