IMAX and premium large formats

IMAX began as a Canadian invention. In the late 1960s a group of Canadian filmmakers and engineers developed a system that ran 70 mm film horizontally through the camera and projector, giving a frame roughly ten times the area of a standard 35 mm frame, projected on screens many stories tall. For decades IMAX meant short documentaries in science centers and museums. Since the 2000s it has also meant Hollywood features, some shot partly or entirely on IMAX film cameras, many shot on IMAX-certified digital cameras and many more converted from standard formats for IMAX release. Other premium large-format (PLF) screens, such as Dolby Cinema and exhibitor-branded large screens, compete for the same audience. This lesson explains the formats, the aspect ratios, the cameras and what they mean for a DP planning a premium release.

The 15/70 film format

The original IMAX film format is called 15/70: 70 mm wide film, running horizontally, with each frame 15 perforations long. In a conventional 35 mm camera the film runs vertically and each frame is 4 perforations tall. Running 70 mm film sideways gives a frame about 70.4 mm wide and 52.6 mm tall, an aspect ratio of about 1.43:1.

Camera negatives for these "70 mm" formats are actually 65 mm wide; the extra 5 mm on 70 mm prints carried soundtracks. IMAX cameras shoot 65 mm negative and IMAX film prints are 70 mm.

Footage, magazines and cost

Because each frame is 15 perforations, film runs through an IMAX camera very fast. That has big consequences for magazine changes, noise and the film budget.

At 24 frames per second that is about 337 feet of film per minute, or about 102.6 meters. A 1,000-foot magazine therefore lasts roughly 3 minutes.

Compare this with standard 35 mm 4-perf, which uses 90 feet per minute at 24 fps. IMAX uses about 3.7 times as much film for the same running time, before any difference in the price per foot.

IMAX film cameras

IMAX film cameras have historically been large, heavy and very loud. The noise made dialogue scenes difficult: the camera could be heard on the soundtrack, so filmmakers often switched to quieter 35 mm or digital cameras for dialogue and reserved IMAX film for spectacle. In 2024 IMAX announced it was building a new generation of quieter, lighter film cameras with the involvement of leading directors and cinematographers. In December 2025 IMAX named the new camera "Keighley", after David Keighley, the company's long-serving quality director, and his wife Patricia. Christopher Nolan's The Odyssey, photographed by Hoyte van Hoytema and released in 2026, was described as the first feature shot entirely on IMAX film cameras, made possible by the quieter design. Details such as weight, magazine sizes and how many cameras exist change as the program develops, so check IMAX's current information.

Working with IMAX film cameras requires specialist technicians and loaders trained on the system, careful magazine logistics, and close coordination with the laboratory. Dailies are usually viewed as scans rather than film prints, but the negative is still precious and irreplaceable.

IMAX-certified digital cameras and Filmed for IMAX

Most premium large-format releases today are shot digitally. IMAX runs a program it calls Filmed for IMAX, in which it certifies selected high-end digital cameras and works with productions to frame and finish for its expanded aspect ratio. Certified models have included cameras from ARRI, RED, Sony and Panavision, and in January 2026 Fujifilm announced that its GFX ETERNA 55 had joined the list. The list changes as new cameras are certified, so a DP planning an IMAX release should check the current list with IMAX and confirm the exact recording modes that qualify, since certification usually applies to specific resolutions and sensor areas.

For the DP, Filmed for IMAX means planning framing for two or more aspect ratios, protecting the taller frame on set, working with IMAX's image specialists during post and delivering masters for different screen types.

Aspect ratios for premium screens

Premium large-format releases often change aspect ratio during the film. Scenes are shown in the standard release ratio, typically 2.39:1 or 1.85:1, and selected sequences open up to a taller ratio on IMAX screens.

• 1.43:1: the full height of the 15/70 frame, shown on a limited number of large IMAX screens with laser or film projection that can display it.
• 1.90:1: the IMAX digital expanded ratio, shown on most IMAX digital and laser screens.
• 2.39:1 or 1.85:1: the standard release ratios for other cinemas and home viewing.

When the width is shared, each taller ratio reveals more picture at the top and bottom. A shot composed only for 2.39:1 may show a microphone, lighting rig or unfinished set at 1.43:1. A shot composed only for 1.43:1 may cut off heads when cropped to 2.39:1.

Framing for multiple ratios on set

Practical habits keep multi-ratio shooting under control.

• Load frame lines for every delivery ratio into the camera and monitors, with different colors or line styles, and agree which ratio is the "hero" for composition.
• Place important action in the common area that appears in every ratio, usually slightly above the center of the tallest frame.
• Brief the art department and grips that ceilings, rigging and top-light units may be visible in the taller frame.
• Agree with visual effects which shots need extra headroom for set extensions.
• Mark which sequences will expand to the taller ratio, so the DP and operator know when to compose for it.
• Record the sensor area that IMAX requires; cropping in post cannot recover picture that was not captured.

Exhibition, laser and premium screens

The audience's experience depends on the screen and projection system.

• IMAX with laser and GT screens: the largest screens, often able to show 1.43:1, with higher brightness and contrast than older xenon projection.
• IMAX digital xenon and smaller laser screens: usually 1.90:1 maximum.
• IMAX 70 mm film projection: a small number of venues can still project 15/70 prints, which became a selling point for some recent releases.
• Dolby Cinema and other PLF screens: high-contrast projection, often with high dynamic range and immersive sound, usually showing the standard ratios.

The DP does not control exhibition, but knowing where the film will play helps decide how much to invest in large-format capture and expanded-ratio sequences.

IMAX and large format in the US

The United States has the largest number of IMAX and PLF screens, and the major studios and streamers plan premium releases closely with IMAX and Dolby. Large-format cameras, IMAX film equipment, specialized technicians and post facilities that can handle large-format workflows are concentrated in Los Angeles, with support available in other production centers. Productions should confirm availability early, as demand for IMAX film cameras and certified digital packages can be high in peak seasons.

Deciding whether to shoot for IMAX

A DP can help the director and producers decide with a few questions.

• Will the film be released on premium screens, and has the distributor agreed to an IMAX release?
• Which sequences benefit from the taller frame and the extra resolution?
• Can the production handle the cost: film stock and processing for 15/70, or certified digital packages, larger data volumes and IMAX post services?
• Will the noise, weight and magazine length of film cameras suit the scenes, or is a certified digital camera better?
• Can the art department, lighting and visual effects support the taller frame?

Answering these early prevents expensive surprises, such as discovering in post that the taller frame shows a rig that cannot be removed.