Actually you're incorrect. The IMAX scenes for the Blu-ray have been cropped from 1.44:1 to 1.78:1. The correct way to present the film on a 16x9 HDTV without losing any picture is a 1.44:1 image pillarboxed. I'm talking about the proper aspect ratio to present the film in. The movie was shot in 1.44:1 (IMAX) and 2.35:1 (35 mm) and it should be presented as such as well.
If they did that in the theater, you'd be looking at massive shifts from a very tall/square fullscreen image to what would seem like a narrow horizontal strip of picture. It could be very distracting, so going from 2.35:1 to 16x9 is less of a /jump', and more sensible for HDTV's...and even movie screens. Even with a 'cropped' IMAX image at 16x9, you're still getting the benefits of more overall initial/captured resolution than 35.
The idea altering the aspect ratio unnerves me. It's synonymous to the argumentation used to pan and scan movies for old CRT TV's. I have a projector so the whole "fits your TV argument" doesn't work for me. I want the entire image that was shot.
Well, you'll have to deal with it if you want the 'full frames' of both the 35mm and IMAX in the same movie. Otherwise, say you have a full 1.44:1 IMAX frame....if you want the 35mm to fill that completely, you'll have to zoom in and centercrop the 35, which would make that look even worse.
IMAX was never really designed to be combined with other formats. and the 'tallness' of the frame is really for true IMAX theaters where audiences can feel like they're 'suspended' in the middle of the image, with both the vertical and horizontal edges just beyond the field of view. But it's just not sensible to only release the film in true IMAX theaters, even if it was all shot on IMAX. So in order to present it in regular 35/digital theaters, with screens/theaters designed around 35mm projection screens...the IMAX would have to be 'center-punched', to fit the full 'square' frame inside the rectangular screen.....
...which would give you the 'full' original IMAX frame, but you'd effectively be shrinking/downres'ing the image even more, negating the actual re****ion/image quality advantage that IMAX offers in the first place. It a better choice to crop the IMAX vertically to fit the full width.
It's best to not worry about what's 'missing' from the original 1.44:1 frame...you're still get a great-quality image with extended depth and detail with what you have left. It's also better to just immerse yourself in the story and what's going on, rather than think too much about how it was done while watching the movie.