The Many Aspects of Ratio
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Posted 31. December 2011.
Have you ever wondered why so many movies come in different screen sizes? These various sizes are called "aspect ratios" and are industry standardized media formats. An aspect ratio is the relationship between width and height; for example, HDTV has an aspect ratio of 16 inches of width to every 9 inches of height, which can be read as 16x9 or, to simplify it further, 1.78:1. This is close to the 1.85:1 ratio of most movies released in theaters. A 35mm film negative has an aspect ratio of 4x3, or 1.33:1. To create the 1.85:1 aspect ratio, filmmakers have a choice of shooting it in 1.33:1 and composing every shot so that nothing is lost when theaters show it as 1.85:1, or they can have the camera modified to shoot it as 1.85:1 without wasted space. Almost all HD digital video cameras shoot at a native aspect ratio of 1.78:1.
To create an even wider aspect ratio of 21x9, or 2.35:1, filmmakers can use an anamorphic lens to squeeze more picture information onto a 35mm negative; in the movie theater, a special projection lens stretches the picture out so that the actors do not look like very tall stick figures. The result is a picture that is much wider than normal. A handful of movies, mainly big-budget epic films like Lawrence of Arabia and Star Wars, are shot this way.
Prior to 1952, all movies were 1.33:1, but when television, which had the same aspect ratio, came along, movie studios fought back with new technologies: 3-D movies, stereo sound, and widescreen. These would not be available in the home for many decades, and when widescreen movies were shown on TV, they were cropped to fit the screen via a method known as "pan and scan," destroying the composition of films in the process. With HDTV now a reality, it is becoming more and more common for TV networks to show movies in their original aspect ratio, putting black borders on the top and bottom or the sides of the screen to fit the display. Many of the movie channels on cable TV and directv.com do this, and almost all Blu-ray discs as well.
The progression of aspect ratios from the very narrow to the very wide is one of the many things that make watching movies so interesting. Hopefully, you will now be able to appreciate some of this technical artistry on another level now that you understand the concept of aspect ratios.
