Apple Final Cut Express HD - Manual (Page 1050)

1050 Part XIII Appendixes
Recording Slow Frame Rates for Time-Lapse Photography
Slow frame rates are used for time-lapse photography, in which a scene is recorded
relatively slowly, perhaps one frame every second, hour, or day. This is useful when you
are trying to capture gradually changing events, such as growing plants, the movement
of clouds, or the rising and setting of the sun. When played back at standard frame
rates, events occur rapidly on screen and otherwise undetectable patterns emerge.
Stop-motion photography, traditional drawn animation, and computer rendering take a
similar approach. The point here is that the rate of creating a frame does not
necessarily correspond to the rate of playback. This is one of the most exciting
propositions of motion pictures and their ability to manipulate time: You can create
images at whatever rate suits you and play them back at a totally different speed.
Examples of How Different Frame Rates Are Used
Film is especially flexible in that it can be photographed and played back with a diverse
range of speeds. Some examples are:
 1 frame per hour: Extreme time lapse photography.
 1 frame per minute: Time lapse photography and stop motion animation.
 18 frames per second: Early motion picture films.
 24 frames per second: Worldwide standard for movie theater film projectors.
 48 frames per second: Slow motion photography (because it takes twice as long to
play back in a 24 fps projector, the motion is twice as slow).
 300+ frames per second: High speed cameras for very slow motion photography
(often used for miniatures to make models seem larger on screen).
 2500+ frames per second: Very high speed cameras for special effects such as
pyrotechnic photography and explosions.
Choosing a Frame Rate
Movies on film are almost exclusively projected at 24 fps. Television, however, does not
have an internationally accepted frame rate. In Europe and many other countries, PAL
and SECAM use 25 fps, while NTSC video in North America and Japan uses 29.97 fps.
Other common frame rates are usually multiples of these.
Note: Converting video formats from one frame rate to another is technically
challenging, and there are often unwanted visual side effects. This is especially true
when the frame rates do not evenly divide. For example, converting 30 fps to 60 fps is
fairly easy to do, but converting 29.97 fps to 25 fps is much more difficult. Making sure
audio stays in sync throughout the conversion is yet another challenge.