"The most important elements of a motion-picture camera are the lens, the shutter, and the two reels that supply the film and take it up again. When a motion-picture camera is in operation, the shutter opens and exposes the film, which receives an image formed by the lens. The shutter then closes and a mechanism called a pull-down claw moves the film along so that it can be exposed once again. In normal operation this cycle occurs 24 times per second, creating 24 separate still photos.

By operating the camera at speeds much faster or much slower than 24 frames per second, the apparent time of a motion can be lengthened or shortened. For example, filming a scene at 72 frames per second, but projecting it at the normal speed of 24 frames per second, slows down the action so that what happens in one second takes three seconds on screen. Operating the camera at a slow frame speed produces the opposite effect and is useful for viewing a very slow process, such as the growth of a plant. When a plant's growth is filmed at one frame every three hours and the film is projected at 24 frames per second, 72 hours of growth are compressed into every second, and on film the plant will appear to spring from the earth.

Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved."

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Редактирано от Щиpлиц на 07.02.05 10:43.