I know I'm a bit late to this particular party, but I had to share some of my observations about Thor, the latest movie adaptation of a Marvel comic-book hero. I actually saw it twice in 3Donce at an ArcLight theater with Xpand active-shutter glasses and again at an Imax theater with passive-polarized glasses.
The ArcLight presentation was the dimmest I've ever seen, confirming that a single projector with active-shutter glasses delivers too little light to the eyes. It was also very loud, though I didn't have my sound-level meter with me. (Fortunately, I did have my earplugs!) My wife wore earplugs and noise-cancelling headphones, which cut out a lot of the bass but left the dialog intelligible.
I decided to see it again in Imax to compare the brightness of active-shutter versus passive-polarized glasses. Sure enough, the image was much brighter thanks to the passive glasses and Imax's use of two projectors for 3D.
The 3D itself was not as good as other titles I've seen, probably because the movie was converted from 2D. And a significant portion was presented in 2D, and I find it a bit disconcerting when a movie switches between them. Also, I thought the CGI didn't integrate well with the live actionit looked too, well, computer generated. Still, it is far better than some other conversions, such as Clash of the Titans.
I did bring my SPL meter to the Imax presentation, expecting it to be extremely loud. But I was shocked to find that the measurements were surprisingly reasonable. The average level over the entire movie was only 74.1dBA, and the highest maximum RMS level within 1-minute intervals was only 89.0dBA. I tried to find a theater manager to ask if they had turned the Imax sound system way down, but no one was able to answer that question.
As for the movie itself, I really enjoyed it. Not only is it directed by Kenneth Branagh, whom I respect very much, but one of the story's authors is J. Michael Straczynski, the creative force behind Babylon 5, one of my all-time favorite sci-fi TV series. Straczynski knows mythology, and he gets it mostly right in this tale of Thor (Chris Hemsworth), son of Odin (Anthony Hopkins), king of Asgard, one of the nine realms of Norse legend. (The world of humans is called Midgard.) Also faithful to the myth are the Frost Giants and their realm of Jötunheim, Mjölnir (Thor's hammer), Yggdrasil (the "world tree" around which exist the nine realms), and Bifröst, the rainbow bridge between Asgard and the other realms that is guarded by Heimdallr (Idris Elba).
One detail that is not true to Norse mythology is the portrayal of Loki (Tom Hiddleston) as Odin's adoptive son, though his origin as a Frost Giant is part of the myth. Loki sometimes helped the gods and sometimes caused them problems, as he does in the movie, but he seems to be a conflicted and deeply troubled individual rather than the mischief maker of legend.
I thought the acting was quite good, much better than the typical super-hero movie based on a comic book. Aside from the actors already mentioned, Natalie Portman does a great job as Jane Foster, the scientist who finds Thor after he is stripped of his powers and banished to Earth for picking an unnecessary fight with the Frost Giants. Stellan Skarsgård and Kat Demmings are also excellent as Foster's mentor and assistant, respectively. Likewise, Ray Stevenson, Tadanobu Asano, Josh Dallas, and Jaime Alexander provide some nice comic relief and kick some serious butt as Thor's warrior buddies Volstagg, Hogun, Fandral, and Sifthe last of whom is Thor's wife in the mythology and not identified as a warrior.
Despite a few deviations from Norse legend and less-than-stellar 3D, I thoroughly enjoyed Thor, and I look forward to its release on Blu-ray. If it's still in a theater near you, I recommend it highly. And be sure to stay through the closing credits, after which is a teaser for the sequel.