2010 HPA Tech Retreat: What Gave Some "Avatar" Viewers Discomfort?

It’s hard to report on the HPA Tech Retreat.  There were almost 100 presentations in the main program, not counting more than 60 breakfast roundtables, four demo rooms (and a truck), and networking lunches, dinners, and strange-rules softball games for the more than 450 registered participants.  Still, it’s worth the effort, if only to recall some of the enlightening highlights.

I’m going to start with something that has been bothering me about a subject I’ve covered here, the seeming need for 2D glasses for some viewers of 3D (see “2D (not 3D) Glasses” http://schubincafe.com/blog/2010/02/2d-not-3d-glasses/).  I could understand the issue for home TVs, where short viewing distances could cause a conflict between visual accommodation (eye focus, which is always on the screen) and vergence or convergence (the aiming of the eyes, which could be far behind the screen or in front of it).  But I had a hard time understanding why there have been so many complaints of 3D discomfort, worldwide, from people watching Avatar in movie theaters.

Avatar seems to have superb 3D, without wild, in-your-face effects.  And movie theaters have viewing distances that should minimize, if not altogether eliminate, vergence-accommodation conflict.  So what was making those viewers (only a minority) queasy?

One possible answer was provided at one of those networking opportunities at the HPA Tech Retreat.  An engineer noted that his wife became queasy at Avatar but had also become queasy at another, non-3D James Cameron movie, Titanic, when the floors and walls shifted and the views got vertiginous.  So maybe it was just people susceptible to queasiness when visual cues don’t match those of the vestibular system (the semi-circular canals of the inner ear), the same conflict that causes sea sickness.  And maybe the reports came out in association with Avatar just because of the magnitude of its 3D buzz.

Unfortunately, at another networking opportunity, a viewer who got queasy watching Avatar said she’d had no discomfort when watching Titanic or even more vertiginous movies.  So what had caused the issue for her?

One of the speakers at the 3D-in-the-Home supersession at the HPA Tech Retreat was Professor Martin Banks, who heads the Visual Space Perception Laboratory at the University of California – Berkeley.  That’s the lab that proved, perhaps for the first time, that there is a vergence-accommodation conflict (see “3DTV: Home and the Range” http://schubincafe.com/blog/2009/11/3dtv-home-and-the-range/).  But that explains discomfort primarily at close home-viewing distances, not in cinemas, especially if what’s being viewed is not in-your-face 3D.

Adam Wilt has provided comprehensive coverage of the HPA Tech Retreat on his ProVideo Coalition Camera Log http://provideocoalition.com/index.php/awilt/story/hpatr2010_1/.  Be sure to go to the other pages and other days of his coverage to get a good taste of the event.

If you scroll down on the first page, you’ll come to some of Banks’s diagrams.  Note that, as far as vergence-accommodation conflict is concerned, “Percival’s zone of comfort” covers most cinema-viewing conditions but not all home 3D conditions.  Scroll down a bit more, however, and you’ll see that 3D has a narrower acceptable viewing angle than 2D, at least for some purposes.  So maybe that’s what’s been causing some Avatar viewers discomfort.  Maybe they were seated outside the acceptable viewing angle.

I’ll get to more of the 2010 HPA Tech Retreat in future posts, but, in the meantime, in addition to Adam Wilt’s coverage, you might check these others:


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