ABSTRACT
Twenty-four frames per second is the standard frame rate for all projectors and fi lm cameras running at what is known as sync speed. While most projectors do not vary this frame rate, many fi lm cameras are built with variable-speed motors, which allows them to alter the frame rate. We can, for example, shoot our fi lm at 8 fps, 12 fps, or 72 fps. When we shoot at a frame rate faster than 24 fps we get slow motion when we project at 24fps. The faster our camera’s frame rate, the slower the motion will appear when projected. A movement that takes one second in real time, like a glass shattering on the fl oor, when shot at 72 fps, will take three seconds on screen, and four seconds if you shoot the glass breaking at 96 fps. Conversely, altering the camera’s speed to frame rates below 24 fps (i.e., 12 fps or 8 fps) will create motion that appears sped up when projected. This is called under-cranking, and the slower the frame rate of the camera, the faster the motion appears when projected (Figure 8-4).
