Pan and Scan

Pan and scan is a method of adjusting widescreen film images so that they can be shown within the proportions of an ordinary television screen, often cropping off the sides of the original widescreen image to focus on the composition's most important aspects. Some film directors and film enthusiasts disagree with pan and scan cropping, because it can remove up to 45% (on 2.35:1 films) of the original image, changing the director's original vision and intentions. The vertical equivalent is known as "tilt and scan" or "reverse pan and scan".
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