Re: Those who cannot see or enjoy stereo

[P3D Ronald W Doerfler <doerfler@xxxxxxxxxxxxxxxxxxxx>]

George ponders audience members who complain of headaches despite
precision mounting and projection (sorry I can't quote--different
computer):

I've noticed that if my head is slightly tilted, such as leaning on
my hand in an auditorium with armrests, the bleeding through
of the opposite image to each eye, even if not consciously noticed,
can give me slight headache symptoms.  Just a thought.

Perhaps these people could be questioned more specifically about
their symptoms.  To me, there seem to be two different effects that
might be described as a headache when asked, but are different.
One is the classic headache that I get after viewing poorly-mounted
slides (like previewing my slides in slip-in mounts).  The other
is a sort of motion-sickness that someone sensitive to it like me
can experience occasionally, which may not be related to mounting precision.
In fact, I don't know why it happens, but it has decreased over the
years as I get used to 3D.  It would be the latter symptom, I would
think, that would cause an audience member to get up and leave in
the middle of a presentation, to get fresh air and relieve the sense
of dizziness.  A straightforward headache would more likely just cause the
audience member to remove the glasses and watch the speaker, etc.
The headache would last longer, as the motion sickness disappears
fairly quickly.

I postulate that the motion sickness may be the oft-seen (by me)
backgrounds in projected slides that swing wildly left or right
with only small head movements, FAR more than what a real-life
scene would do.  I have mentioned this to a couple of other people,
who never noticed it.  It varies in magnitude with different slides,
and I don't know whether the "wildly swinging backgrounds," as I
call it, is accentuated by mounting to the window rather than
infinity, or what.

For what it's worth.

Ron Doerfler (landlubber by design, who must REALLY like 3D)


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