The classic format of 35-mm film is 1,375:1 (= 12,5:9). This format is used mainly in amateur and documentary use. In the movie it is increasingly wide-screen formats with the ratios 1.66:1 (15:9) and 1.85:1 (16,65:9) one. These ratios are generated by corresponding picture window in the movie camera or Mask in the projector, which are inserted into the beam path. It is also used just a small cut of each film frame and then stretched this proportion. (Further explanation in open matte .)

When Cinemascope process goes to a different way: The original ratio of 2.35:1 (21:9) is using an anamorphic lens housed in a 1:2 ratio to the footage: The height of the image is preserved, the image acts but compressed in the width. The demonstration of the finished film, the image must, however, with a special cylindrical lens ( anamorphic are called) again equalized.

In the 1950s and early 1960s were years of experimenting with different methods and aspect ratios. Another inexpensive method was Vistavision , since only converted cameras were needed, but the recordings still on 35-mm film. The aspect ratio was 1,96:1 here.

TV and Video

In the analog 4:3 TV was a common format, both the German PAL and the French SECAM or the U.S. NTSC . From the 1990s, increasingly the format was 16:9 (= 1.78:1) was used.

The digital television standards such as DVB and ATSC support in a variety of pixel aspect ratios, the display aspect ratios 16:9 and 4:3 as well as theoretically 2,21:1 (about 20:9), which is not used in practice. When high-definition television aspect ratio is 16:9 usual.

In DVD , SVCD , DVB, the images are often stored anamorphic - analogous to the Cinemascope process.

Screen aspect ratios

Especially for larger and high-quality televisions prevailed with the digitization and the move away from the cathode ray tube, the aspect ratio of 16:9. From 2009 even broader device came in 21:9 format (7:3 = 2.33:1) on the market, which films in the format of 2.35:1 can display without horizontal stripes, with no source optimized for this material exists and the Most of the content with vertical bars or inflated or distorted must be displayed.

http://www.pptphotography.net/