15/70

Originally developed by the Imax Corporation in 1970, this format uses 70mm film run through the projector horizontally, so that the width of the film is the height of the frame. In all other LF and conventional formats, the film runs vertically, so that the width of the film is the width of the frame.

Each frame is 15 perforations wide, hence 15/70. The area of the frame is about 52mm high by 70mm wide (2 inches by 2.75 inches). 

The 15/70 frame is almost nine times larger than the conventional 35mm frame (below) used in neighborhood movie theaters. It is slightly less than twice as large as 8/70.

Although Imax Corp. was long the exclusive maker of 15/70 projectors and cameras, other manufacturers now make 15/70 systems.

10/70

Produced exclusively by Japan's Goto Optical Manufacturing for its planetarium customers, 10/70 is optimized for projection onto a dome. Known as Astrovision, 10/70 is found in theaters in Japan, China, South Korea, and Taiwan. Virtually all films presented in 10/70 theaters were originated in 15/70 and printed to 10/70.

8/70 

The 8/70 format runs vertically, with a frame that is about 38mm high and 52mm wide (1.5 inches by 2 inches.) Because 8/70 uses about half as much film per minute as 15/70, shooting in 8/70 is less expensive and prints are about half the cost of 15/70 prints.

Many manufacturers produce 8/70 projectors.

In 2008, Imax Corporation began the rollout of its digital projection system, which uses two Christie 2K projectors and proprietary processing to increase resolution above 2K. With an aspect ratio of 1.9, this system is intended to be installed in existing multiplex auditoriums on screens no more than 70 feet wide.

In its present configuration, this system does not match the image quality of any of the giant-screen film formats above.. 

Rarely seen in theaters now, this was once the premiere format for high-quality conventional film production and exhibition. Frame area is about 23mm high and 52mm wide (0.9 inches by 2 inches ).