Time-lapse Photography - Terminology

Terminology

The frame rate of time-lapse movie photography can be varied to virtually any degree, from a rate approaching a normal frame rate (between 24 and 30 frames per second) to only one frame a day, a week, or more, depending on subject.

The term "time-lapse" can also apply to how long the shutter of the camera is open during the exposure of each frame of film (or video), and has also been applied to the use of long-shutter openings used in still photography in some older photography circles. In movies, both kinds of time-lapse can be used together, depending on the sophistication of the camera system being used. A night shot of stars moving as the Earth rotates requires both forms. A long exposure of each frame is necessary to enable the dim light of the stars to register on the film. Lapses in time between frames provide the rapid movement when the film is viewed at normal speed.

As the frame rate of time-lapse approaches normal frame rates, these "mild" forms of time-lapse are sometimes referred to simply as fast motion or (in video) fast forward. This type of borderline time-lapse resembles a VCR in a fast forward ("scan") mode. A man riding a bicycle will display legs pumping furiously while he flashes through city streets at the speed of a racing car. Longer exposure rates for each frame can also produce blurs in the man's leg movements, heightening the illusion of speed.

Two examples of both techniques are the running sequence in Terry Gilliam's The Adventures of Baron Munchausen (1989) in which Eric Idle outraces a speeding bullet, and Los Angeles animator Mike Jittlov's 1980 short and feature-length film, both titled The Wizard of Speed and Time, released to theaters in 1987 and to video in 1989.

An animated example is the clip from the show "The Simpsons" in which Homer Simpson takes a picture of himself a day for 39 years, although it is intended to be a comedy, thus not realistic.

When used in motion pictures and on television, fast motion can serve one of several purposes. One popular usage is for comic effect. A slapstick style comic scene might be played in fast motion with accompanying music. (This form of special effect was often used in silent film comedies in the early days of the cinema; see also liquid electricity.)

Another use of fast motion is to speed up slow segments of a TV program that would otherwise take up too much of the time allotted a TV show. This allows, for example, a slow scene in a house redecorating show of furniture being moved around (or replaced with other furniture) to be compressed in a smaller allotment of time while still allowing the viewer to see what took place.

The opposite of fast motion is slow motion. Cinematographers refer to fast motion as undercranking since it was originally achieved by cranking a handcranked camera slower than normal. Overcranking produces slow motion effects.