What Is Frame Rate?
(p. 405)
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Understanding Flicker and Perceived Frame Rate
(p. 406)
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Frame Rate Limits: How Many Frames per Second Is Best?
(p. 407)
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Choosing a Frame Rate
(p. 408)
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What Is Timecode?
(p. 410)
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About Drop Frame and Non-Drop Frame Timecode
(p. 410)
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Timecode on Tape
(p. 413)
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Comparison of Various Timecode Formats
(p. 414)
What Is Frame Rate?
Think of a motion picture camera as a relentless still camera, taking many still
photographs every second. Movies create the illusion of motion by showing still
images in rapid succession. The number of images photographed per second is
referred to as the frame rate of the movie, and is measured in frames per second (fps).
Frame rate describes both the speed of recording and the speed of playback. The more
frames recorded per second, the more accurately motion is documented onto the
recording medium.
Recording and playback speed are usually the same, though they do not have to be.
For example, if you film a rubber ball bouncing on a sidewalk at 24 frames per second,
your movie will have 24 unique photographs of the position of the ball. However, if you
film at 100 frames per second, there are nearly four times as many photographs of the
ball’s position during the same period of time. The more frames per second, the more
precisely the exact position of the ball is documented.
Note: If you play back frames at a speed different than the original recording speed,
you can create temporal effects such as time lapse and slow motion.
406
Part V
Appendixes
Early television systems selected frame rates based on local electrical standards to
avoid electrical interference with the picture. NTSC in North America uses 30 fps (now
adjusted to 29.97 fps for color NTSC) based on 60 Hz electrical power. PAL, used
primarily in Europe, uses 25 fps based on 50 Hz electrical mains.
Because film cameras are relatively simple compared to video cameras, they allow
shooting and playing back with a wide range of frame rates (although the standard
projection speed is 24 fps). Video formats are much less flexible, partly because of their
electronic complexity and partly because a television is designed to play video at only
one frame rate. However, as video technology evolves, many digital camcorders now
offer several frame rate choices while maintaining compatibility with existing NTSC and
PAL video systems.