A story a decade in the making with a massive cast and a huge budget, Avengers: Infinity War is shaping up to be a film unlike any other. As such, it only makes sense that the culmination of the MCU to this point would break new ground on a technical level as well. Infinity War is the first Hollywood film to be filmed entirely using IMAX cameras. Beyond just being a cool claim the movie can make, the innovative cameras and IMAX format worked really well for the scope and cinematography of Infinity War, as co-director Joe Russo explained:
We have a lot of characters who are tall, unnaturally tall. So it really helps with the frame, because that IMAX aspect ratio works for those types of characters, and the landscapes are stunning. There are some really exotic landscapes in the film, and to be able to put those on an IMAX screen, it's an incredible tool to have as a filmmaker to be able to exploit that scale of aspect ratio.
Joe Russo makes an interesting point here about how the height of some of the actors can make framing and composition a bit of a challenge. Characters like Thanos, Hulk, and the Black Order are all inhumanly tall, so IMAX is the perfect way to film them. Additionally, the film's actors like Chris Hemsworth, Chris Pratt and Dave Bautista are all over 6-foot, so it helps facilitate them as well. The IMAX aspect ratio is different from most films that have a widescreen aspect ratio of 1.85:1 or 2.35:1. True IMAX has a great deal more height to the frame at a 1.43:1 aspect ratio. So this taller frame helps for shooting these tall characters, who must also sometimes share the screen with smaller guys like Rocket Raccoon.
Speaking during a set visit that CinemaBlend and other outlets attended last year, Joe Russo also touched on the fact that the different aspect ratio of the IMAX format allows for incredible cinematic vistas of the various landscapes in the film. Even on a small computer screen, the sweeping shots of Wakanda in the new final trailer are stunning, and give you a sense of what sort of cinematic feast this film will be. The image quality and size of the frame that IMAX affords will really lend this movie the sort of epic scope and feel that a battle this big, this long in the making, should have.
IMAX cameras have historically been big, heavy, noisy and anything but user friendly. That's why even the format's greatest champions like Christopher Nolan have only been able to shoot a portion of films using the cameras. But the new digital IMAX Arri 65 camera that Infinity War is being shot on allows greater freedom and mobility, which means that they were able to shoot the entire film in IMAX. This makes its release even more exciting, and seems rather fitting for a film of this scale.