Generally refers to the use of 16:9 aspect ratio pictures in a 4:3 system. For example, anamorphic supplementary lenses are used to change the proportions of an image to 16:9 on the surface of a 4:3 sensor by either extending the horizontal axis or compressing the vertical. Signals from 16:9 cameras and telecines produce an ‘anamorphic’ signal which is electrically the same as with 4:3 images but will appear horizontally squashed if displayed at 4:3.

The alternative way of carrying 16:9 pictures within 4:3 systems is letterbox. Letterbox has the advantage of showing the correct 16:9 aspect ratio on 4:3 displays, however the vertical resolution is less than 16:9 anamorphic.

See also: Aspect ratio – of pictures