Originally Posted by
DVDfever:
“I didn't realise there was a difference, but they had a small black bar at the top only (maybe it wasn't quite aligned correctly) giving a ratio of approx 16:9, and it looked like a combination of cropped and open-matte shots. I've since seen the trailer again (in 2.35:1) and this supports that theory, eg. the clip of Noomi looking through a gap was cropped for the IMAX version I saw, but a two-person shot of her and her boyfriend were open-matte.
Bit of a shame I spent half the film thinking, "Hmm.... cropped or open-matte?" 
Did the ratio of Hunger Games change mid-film, then? I haven't seen a film do that, as this is the only major film I've seen in IMAX, but I heard Mission Impossible Ghost Protocol did that. Doesn't the change look a bit jarring for some of the audience?”
It did, although only a couple of times and to be honest i actually barely noticed it when it "opened up" to fill the screen. The only occurence that i can actually remember was during the fire sequence in the forest. It was the same for John Carter too, although if my memory serves me correctly i think the black bars were there for the entirety of the film and it never opened up, i may be wrong there though.
The aspect ratio change itself isn't actually that jarring really, it tends to blend seamlessly with an edit. The Dark Knight Blu Ray actually changes aspect ratio during the film at certain points for the IMAX footage, and while it is noticeable, it isn't annoying, especially when the IMAX footage is so striking.
Originally Posted by eyeblink:
“MISSION IMPOSSIBLE: GHOST PROTOCOL did change ratio - I saw it at the BFI IMAX on New Year's Day. About half an hour of it was shot in IMAX (including the Burj Khalifa sequence - and that looks really impressive, I can tell you, as long as you don't suffer from vertigo) and that footage used the whole screen, i.e. was shown in 1.44:1. The rest of it was shot 35mm anamorphic, and was letterboxed into 2.39:1 or thereabouts.
I'm not sure what CJClarke means by a "proper" IMAX screen, by the way... PROMETHEUS did have black bars when I saw it in IMAX 3D - according to the IMDB, into a ratio of 1.78:1 which would be the native ratio of a digitally-captured film.
I can't comment re THE HUNGER GAMES as I didn't see it in IMAX - in 4K digital it was in 2.39:1 throughout. (Shot in 3-perf Super 35, so it could possibly be opened up to 1.78:1 if needs be.)”
When i say "proper" IMAX i'm talking about the full 70mm IMAX (like the one at the BFI or the Odeon in Manchester) which still uses 70mm film rather than a digital "print". There are two types of IMAX theatres, there's the 70mm IMAX and then there's the IMAX Digital theatres which are much more widespread and are actually considerably smaller in size than the 70mm "proper" IMAX screens. I'm no expert on aspect ratios, but i would imagine that if you saw it on a 70mm IMAX then the image may well have been cropped due to the sheer size of the screen coupled with the fact that Prometheus was an IMAX conversion (i.e. not filmed in IMAX), whereas the IMAX Digital version fills the screen as it has less space to fill.
This link will explain it better than i can:
http://www.slashfilm.com/qa-imax-the...l-imax-liemax/
For the record though, i disagree with the way they label IMAX Digital as "Fake" IMAX or "Liemax", as even though it's undeniably smaller it is still massive compared to other regular screens and still very impressive. The one that opened in Sheffield in March is the second biggest IMAX Digital in the world (apparently) and even though it's not "proper" IMAX it's still stunning compared to regular cinema screens.