Film frame
From Wikipedia, the free encyclopedia
A film frame, or just frame, is one of the many single photographic images in a motion picture. The individual frames are separated by frame lines. Normally, 24 frames are needed for one second of film. In ordinary filming, the frames are photographed automatically, one after the other, in a movie camera. In special effects or animation filming, the frames are often shot one at a time.
The term may also be used more generally as a noun or verb to refer to the edges of the image as seen in a camera viewfinder or projected on a screen. Thus, the camera operator can be said to keep a car in frame by panning with it as it speeds past.
The size of a film frame varies, depending on the film format. In the smallest 8 mm amateur format, it is only about 4,8 by 3,5 mm, while an IMAX frame is as large as 69.6 by 48.5 mm. The larger the frame size is in relation to the size of the projection screen, the sharper the image will appear.
The most common film format, 35 mm, has a frame size of 22 by 16 mm.
[edit] Video frame
In film, video production, animation, and related fields, a frame is one of the many still images which compose the complete moving picture. Historically, these were recorded on a long strip of photographic film, and each image looked rather like a framed picture when examined individually, hence the name.
When the moving picture is displayed, each frame is flashed on a screen for a short time (nowadays, usually 1/24th, 1/25th or 1/30th of a second) and then immediately replaced by the next one. Persistence of vision blends the frames together, producing the illusion of a moving image.
The video frame is also sometimes used as a unit of time, being variously 1/24, 1/25 or 1/30 of a second, so that a momentary event might be said to last 6 frames.
The frame rate, the rate at which sequential frames are presented, varies according to the video standard in use. In North America and Japan, 30 frames per second is the broadcast standard, with 24 frame/s now common in production for high-definition video. In much of the rest of the world, 25 frame/s is standard.
In film projection, 24 frames/s is the norm, except in some special venue systems, such as IMAX, Showscan and Iwerks 70, where 30, 48 or even 60 frames/s have been used. Silent films and 8 mm amateur movies used 16 or 18 frames/s.
