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experimental optics
feylike
have experimentally confirmed that RealD 3D (TM) viewing glasses use circular polarizers, without using any specialized apparatus. method is an exercise for the reader. (i might provide hints on request.) i'm not sure i'm a fan of the projection technique, though.

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CP is clearly superior to LP.
My understanding is that there are two totally different systems used under the same RealD name. One uses two syncrhonized projectors with CP filters. The other uses a single project and a Kerr cell. The former is, quite obviously, much superior.

hm, i thought it was an liquid crystal-switched circular polarizer (liquid crystal shutter with only one linear polarizer layer plus a quarter wave plate?). Kerr cells tend to need toxic liquids and many kilovolts...

RealD apparently also does active shutter glasses, but those are probably not economical for commercial cinema. the one i viewed was single projector with what looked like an externally mounted modulator. also probably single-chip DLP, though color striping was only really visible when looking at the projector, and not so noticeable on-screen.

It's possible I misrecall and/or was misinformed about the precise nature of the polarization modulator.

I'm not aware of shutterglasses ever having been used under the RealD name; they were used for the older IMAX 3D systems, and were far superior to CP... but, yeah, expensive.

Single-chip DLP displays drive me batty. The cinemas here I've been to are all 3-chip, thank the gods.


Easy enough if you have two pairs to play with. Or one pair and a pair of polarized sunglasses. Or can take them outside on a sunny day. Or are just around a shiny surface... maybe not everyone plays with polarization as much as I do?

yes. one pair, indoors, using only ordinary household objects... granted, their behavior in the cinema (preserving stereo separation) upon tilting the head was already highly suggestive of circular polarization; i just wanted to do the obvious confirmatory experiment.

Is a laser pointer an ordinary household object these days? :)

heh. geek household object, perhaps. definitely an ordinary office object. (though i suspect non-geek cat owners are more likely to have laser pointers)

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