09 Time Lapse Photography
Edgerton took his strobes under water to record the leisurely life of the sea floor, using time-lapse photography.
This method combines a motion-picture camera with a strobe. At regular intervals, the strobe flashes and a single frame of film is exposed and advanced. When the movie is shown at normal speed, the action is speeded up greatly, turning barely-perceptible movement into rush hour.
Watch this video in which Doc Edgerton explains the benefits of “speeding up” and “slowing down” time!