In your reading on Christopher Nolan’s new blockbuster adaptation of “The Odyssey,” you might have stumbled across the fact that it is the first mainstream, full-length feature film to be shot entirely with IMAX 70mm cameras. Nolan is fond of the format, and several of his bigger hits were shot partially in IMAX, but he usually saved the larger cameras for key action scenes. “The Odyssey” is the first one that was made entirely in IMAX.
All that sounds impressive, although some may still be a little bit in the dark as to what “IMAX 70mm” actually means. Indeed, when buying a ticket for “The Odyssey,” one might be confronted with a prompt asking whether they want to see it on IMAX screens or merely on 70mm… and not really knowing the difference. Parsing out the differences will lead us down a gloriously nerdy path, involving film formats, the promised sizes of an IMAX screen, and some of the “imposters” — nicknamed “LieMAX” — out there in the world. Luckily, we’re here to walk you through the formats and let you make informed decisions.
Many of us probably know that for the bulk of film history (at least, since 1934), mainstream movies were printed on 35mm-wide film strips, and were run through a projector, top to bottom. At the time, most movies were presented in a near-square 1.35:1 aspect ratio. The size of a film strip has nothing to do with an image’s aspect ratio. In 1953, with the release of “The Robe,” a mass audience was introduced to CinemaScope, a widescreen aspect ratio that required special lenses to both shoot and to project. CinemaScope films were a nice, broad 2.39:1 aspect ratio. They were still, however, shot on 35mm film.
70mm would come into play a few years later.
Oklahoma! was the first major motion picture to use 70mm film
The problem with projecting a CinemaScope movie from a 35mm-wide film strip is that there will always be some image distortion. If you’ve ever seen a Scope 35mm film strip, you’ll see that the image looks “squished” in the frame. It’s only by projecting it through a longer Scope lens that the image is correctly “stretched.” In so doing, however, focus becomes an issue. As someone who has worked in projection booths for several years, I can relate that a projectionist can choose between keeping the very center of a Scope frame in focus, or the edges. It’s never perfect.
In 1955, film pioneers fixed this problem by doubling the size of the film strips. 70mm film had been around for many years, of course, but the first major movie released in the format was “Oklahoma!” in 1955. With a film strip that was twice as big, the image suddenly became that much clearer. 70mm essentially has double the detail of a 35mm film. 70mm movies were still threaded through a projector top-to-bottom, with its perforations — the film strip’s sprocket holes — on either side of the image.
IMAX images were also 70mm wide, but the film was redesigned and reconfigured to run horizontally through a projector. It was also typically presented in a taller 1.43:1 aspect ratio. The visual fidelity was greater than ever, and IMAX movies upped the ante by promising particularly large screens. A true IMAX screen is 59 feet tall by 79 feet wide. Some can be up to 118 feet wide. It can take up a viewer’s entire field of vision. Beginning in 1971, science and nature documentaries were filmed in the IMAX format and presented at special museum theaters.
IMAX went digital, but some theaters still have IMAX 70mm screens
In terms of visual fidelity, as laid out by the DFI Rentals website, an IMAX presentation is the equivalent of a 16k to 18k digital image. An IMAX 70mm presentation, then, is projected on horizontal-running, 70mm film strips onto a 59 by 79-foot screen.
If you see ads for a movie that is in 70mm, but not on an IMAX screen, know that it is still on a gloriously rich and rare film format. Sadly, both formats are kind of rare. There are only about 45 theaters in the entire world that can project movies in the IMAX 70mm format. The website in70mm.com lists all the theaters in North America currently equipped to run 70mm films.
Here’s where the biggest difference between IMAX and IMAX 70mm comes in:
In the year 2008, IMAX joined the digital revolution by converting some of their movies to a lower-fidelity 2k digital projecting format. IMAX would run two 2k projectors at the same time, making the image brighter … but with greatly lessened resolution. Also, the aspect ratio was changed to a wider 1.90:1, and the screens for the IMAX format began to shrink … even though the ticket prices remained the same. This reduced version of IMAX led many film purists to begin complaining of “LieMAX” theaters.
In 2014, IMAX began converting to 4k laser technologies, but the resolution was still much less than their 70mm presentations. Also, both digital formats tend to be at the 1.90:1 aspect ratio, meaning a film shot in IMAX will have the top and the bottom of the image cropped off. The Engaget website has a visual example of this. The laser projectors are much brighter, but know that IMAX 70mm is the genuine article.
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