P3D Re: Photography vs Stereography

[aifxtony@xxxxxxxxxxxxx (Tony Alderson)]

>Bruce Springsteen wrote (digest 2871):
>I have always enjoyed moving my head and body around at Imax shows to
>enhance the sense of moving through space. ... If I sit forward on my
>chair, lean into turns, scan up and down, cock my head and rotate my
>waist, the inner-ear-peripheral-vision-stereo-sound effect can be a real
>thrill, a total body adrenaline rush. But I imagine that 3D goggles
>prevent that. Unless I missed something, I'm guessing that the 3D requires
>me to sit upright and face essentially front and center, like a good
>pupil. Am I assuming correctly? Anybody else bothered by the trade-off? <

The amount of head movement allowed depends on the type of viewers. IMAX
LCD shutter goggles allow a lot of head twisting (it is a time-based
channeling).  Linear polarized glasses, of course, require your head to be
kept fairly straight.  Circular polarized glasses also allow head tilt, but
they are not as efficient as linear polarizers, and they are more
expensive, so not many theaters use them (no IMAX that I'm aware of).

I'm told the worst system for head restrictions was the autostereo theaters
in the Soviet Union. These required precise placements for the seats, and
had a very narrow range to get the 3D.  Eventually these were replaced by
polarized glasses and conventional silver screens. I don't know how much of
the Soviet 3D movie system has survived...The only Soviet 3D I saw was at
the Vancouver Expo, and that was polarized.

Tony Alderson
aifxtony@xxxxxxxxxxxxx




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