P3D Re: Interlens spacing

[George Themelis <gthemelis@xxxxxxxxx>]

--- "Robert A. Schreiber" <bschreib@xxxxxxxx> wrote:
> Would someone calculate how much of a difference a 59mm
> vs. a 65mm center-to-center lens would make at say, 8 ft. ?

So, you are essentially asking what effect does the stereo base
have on the recorded and perceived stereo image.  The effect you
can measure with a ruler is on the stereoscopic deviations (the
little shifts between objects in the horizontal direction that
are responsible for our sense of depth).  The formula for that
is d=FB/I (where F is the focal length, B the stereo base and I
the distance).  

What you cannot measure is the effect that this has on the way
you see the stereo image.  Try using a single camera and a slide
bar to take two pictures one with 59mm and one with 65mm and
tell us if you see any differences and what these difference
are.  That would be an interesting experiment.  Let us know what
you find!

> And would I perceive a shot taken with a 65mm lens
> differently than someone with a 65mm interocular spacing ?  

That's impossible to answer because even if we could change our
interpupilar spacing (distance between the eyes) at will, we
still cannot tell what effect does that have on the way we "see"
things if we were born and experienced the world with one
spacing vs the other.

I remember reading in the paper about a child that was born with
a deformation that lead to a very wide eye spacing.  I forget
the amount... It might have been 4 inches or so.  How different
does this child see our world?  It is hard for scientists to
tell.  In theory he should have increased stereo perception.  (I
don't remember if he even had stereo vision or if this
deformation made the visual fields overlap less, etc.)

=====
George Themelis (DrT-3d@xxxxxxxxxxxxxxxx)
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