This Module is part of the Cinematography section of the Movie Making Manual
Please note that much of this content is present in WikiPedia and we should try to consolidate the two.
The aspect ratio of a screen is its width-to-height ratio. Aspect ratio is independent of screen size. A television screen 14 inches wide and 10.5 inches high has the same aspect ratio of a television screen 25 inches wide and 18.75 inches high. This aspect ratio is 4:3, or 1.33:1 (1.33 times as wide as it is high).
When referring to the aspect ratio you generally refer either to the terms “4 by 3” or “16 by 9” for television; for film you refer to the aspect ratio as the numerical term, eliminating the decimal point and the “:1.” Therefore, you would refer to 1.85:1 as simply ”one-eight-five.”
A topic related to aspect ratio is that of Pixel aspect ratio
Cinema and television screens have used a number of different aspect ratios over the years. The following are the common ratios in use today:
- 1.33:1 aka 4:3. Standard for non-widescreen television.
- 1.37:1 (aka “Academy Standard Flat”) This is the frame size of standard 35mm sound film when using 4 perferations. While no films are distributed in this format many projects are shot in 1.37:1 and matted (or cropped) horizontally to fit other aspect ratios.
- 1.66:1 (aka "European widescreen") Matting the Academy Standard Flat on the top and bottom to achieve a wider aspect ratio derives this aspect ratio. Super 16mm is natively 1.66:1.
- 1.77:1 (aka 16:9) This is the standard ratio for widescreen television and all HDTV formats.
- 1.85:1 (aka "Academy Standard Flat Matted") This is one of two major projection formats in American cinema, derived from matting the Academy Standard Flat on the top and bottom to achieve a wider aspect ratio. This aspect ratio can be shot using a 3-perf 35mm camera without wasting any negative. 3-perf 1.85:1 is becoming very popular again in this age of the Digital intermediate.
- 2.35:1 This is usually achieved by matting the 4-perf academy standard 35mm frame. But this wastes a lot of the negative so many people prefer to shoot using matted 3-perf or 2-perf (2-perf was once known as Techniscope). 2-perf uses the least film but it's also the rarest so it's tough to find the cameras and the telecine facilities.
- 2.39:1 AKA Anamorphic. This is the widest format available for modern cinema. It uses standard 35mm sound film with the image squeezed horizontally using anamorphic lenses. When projected a special anamorphic lens unsqueezes the image. These anamorphic lenses have some disadvantages compared to normal lenses.