What an Aspect Ratio Actually Is
Aspect ratio is the shape of the image - its width relative to its height. Standard cinema widescreen is 2.39:1 (wide and short). IMAX uses taller ratios to fill more of your vertical vision, and that is the whole point of the format. Learn the fundamentals in how aspect ratios affect movies.
1.43:1 vs 1.90:1 - the Two IMAX Frames
IMAX has two signature ratios. The taller 1.43:1is “true IMAX,” produced by 15/70mm film and a handful of premium digital screens. The wider 1.90:1is “full IMAX digital,” used by most IMAX with Laser and Xenon auditoriums.
| Ratio | Name | Source | How it feels |
|---|---|---|---|
| 1.43:1 | True IMAX | 15/70mm film, select digital | Tallest - fills vision top to bottom |
| 1.90:1 | Full IMAX digital | IMAX with Laser / Xenon | Taller than widescreen, very wide |
| 2.39:1 | Standard widescreen | Most cinemas | Wide and short (reference) |
The “Expanding Frame” Effect
In films shot partly on IMAX, the image switches between widescreen and the tall IMAX ratio. When an IMAX sequence arrives, the picture literally opens up - top and bottom bars vanish and the frame grows by up to ~40%. It's the signature moment in Oppenheimer and Interstellar.
📐 Why it changes your seat
Which Should You Pick?
If a film was shot on IMAX film, seek out a 1.43:1 screen - you'll see the most image. For everything else, 1.90:1 IMAX with Laser is excellent and far more common. See the full technical picture in the IMAX guide.