Fast motion

Visual effect that occurs when film is advanced at less than twenty-four frames per second, so that when the film is projected at standard speed the action appears accelerated. Most silent films were shot around 16 frames per second, thus the motion appears fast, and sometimes this herky-jerky motion is associated with them. Fast motion was a favorite technique of director Mack Sennet, who used it in silent comedies and it has since been used in more modern pictures such as Tony Richardson's "Tom Jones" (1963).