P3D Re: 1/30 rule, close-ups, aesthetics

[Bruce Springsteen <bsspringsteen@xxxxxxxxx>]

A while ago in this thread, on larger than ortho-base portraits with near
backgrounds, George said:
> >(... )The portrait is a very distortion-sensitive subject and needs to
> >be treated with a lot of respect.  Better safe than sorry. Less
> >is almost always better.  (...)


Abram K. responded:
> This obviously is on aesthetics. George doesn't say that the
> mentioned portrait is not viewable, but that it can show an
> unpleasant distortion.
(...)
> the distortions in viewing Macro Realist slides are often
> very obvious, especially with recognizable familiar objects.
> Flowers of which you know they are perfectly circular
> can become oval, streched in depth.
> The cause of the stretch is a significant difference in
> convergence when looking at a real object (or person)
> compared with the one in the 3D illusion.
> Is the distortion always unpleasant? No, but often it is
> in portraits.
> 
> This is what Ferwerda in his book called "close-up misery".

We seem to be talking about two things at once, and I'm confused now.  To
me the word stretch is a very specific "deformation" (Ferwerda's term for
deviations from ortho-stereo), related to angle of view, and unaffected by
base increases.  Those oval flowers must be due to something other than
high base-to-subject ratio, if I'm not mistaken.  The deformation (not
distortion) in the portrait situation seems more due to the fact that we
aren't accustomed to seeing shrunken heads up close (the effect we expect
with base increase) and we find it aesthetically unnerving, as Abram
notes. When such wide-base, near-object convergences creep too near the
limit of our close stereo-cyclopean imaging ability, the "deformation"
becomes a "disturbance" (Ferwerda's name for conditions that make
stereo-viewing painful and at some point impossible).  That event -
reaching the visual system's stereo limit - is what I associate with
"close-up misery", and rather than "stretch" I would coin something like
"dysfusion" or "high-convergence cyclopean image rupture due to excessive
retinal disparity". ;-)

BTW, this is speculative floundering on my part, not scholarship - please
don't anyone construe this as authoritative analysis, especially you
beginners.  I'm sure I'll be corrected in short order.

Bruce (the Sacrificial Lamb) Springsteen

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