How does an IMAX camera work?

I'd love to pull back the curtain on how these giant cameras work! To help me tailor our conversation and make it as useful for you as possible, which of these sounds closest to what you are looking for?

A mix of both! I want to understand the tech and the visual magic.

The Magic of Maximum Image

To understand the visual magic of IMAX, we have to start with the physical size of the film itself. The name IMAX actually stands for "maximum image," and the core secret behind its stunning detail is an incredibly simple concept: the bigger the canvas, the sharper and more immersive the picture. For decades, the gold standard of cinema was standard , which runs vertically through a camera. But IMAX completely changed the game by utilizing massive and running it horizontally. This sideways movement allows each individual frame to be massive—giving the image unparalleled room to breathe.

A side-by-side physical scale comparison of a standard 35mm vertical film frame and a massive 15/70mm horizontal IMAX film frame.

Running this giant film horizontally means the camera has to pull a massive amount of physical material past the lens at lightning speed. It is a violent, high-precision mechanical feat that gives IMAX movies that legendary, crystal-clear detail where you can see every single speck of dust or individual eyelash on a screen that is stories tall.

Make me a diagram of the film frame dimensions

You've got it! Let's map out exactly how these frame dimensions compare, because seeing the physical difference in scale is where the

Make me a diagram of the film frame dimensions

You've got it! Seeing the physical difference in scale is exactly where the math meets the visual magic.

Standard movie theaters use standard , but IMAX completely blows those dimensions out of the water with its massive 15/70mm horizontal frames. Let's start generating a visual comparison so you can see how much more screen real estate we're talking about.

A scale comparison of standard 35mm vertical film frames and massive 15/70mm horizontal IMAX film frames.

As you can see, a standard 35mm frame has an image area of roughly

350\text{ mm}^2

. In contrast, the monster IMAX camera aperture measures a whopping

70.41\text{ mm} \times 52.63\text{ mm}

, which yields a massive surface area:

\text{Area}_{\text{IMAX}} \approx 3705.7\text{ mm}^2

That is more than ten times the physical canvas of standard film! When you project an image that large onto a screen stories tall, you don't need to stretch the image nearly as much, which is why everything looks spectacularly sharp instead of blurry and pixelated. But running film this big horizontally creates a massive mechanical problem. Because the film is so heavy, conventional gears would tear the sprocket holes right off the strip if they tried to pull it through at the standard 24 frames per second.

Continue to the 'rolling loop' mechanical solution

The Rolling Loop: A Violent Stroke of Genius

To pull a massive, heavy strip of 70mm film horizontally at a blistering speed of 24 frames per second—translating to about —conventional camera gears simply will not work. In standard cameras, physical metal claws mechanically lock into the film's sprocket holes to yank the film down frame by frame. But if you tried that with heavy, wide IMAX stock, those tiny claws would instantly shred the sprocket holes to pieces, destroying the film and jamming the camera. To solve this, IMAX creators turned to an ingenious, surprisingly fluid mechanism called the rolling loop. Instead of mechanically pulling the film by its delicate perforations, the rolling loop system uses a series of high-speed air compressors and rotating blocks to wave the film through the camera in a smooth, undulating wave—like a physical ripple passing down a whipped garden hose.

A technical cross-section of a horizontal film strip forming a smooth, wave-like rolling loop over a registration pin and vacuum suction plate.

As each wave or "loop" of film rolls into the camera's aperture, it momentarily flattens out entirely. In that brief, fraction of a millisecond, the film is sucked completely flat against the lens backing plate using a powerful system. This vacuum pressure ensures that the massive frame remains perfectly flat and rock-steady during exposure, before releasing it so the next rolling wave can glide in. This brilliant design allows the film to move incredibly fast with virtually zero mechanical friction, keeping the sprocket holes completely safe.