motion-picture photography at a camera speed higher than the normal speed of motion-picture projection (24 frames per second in professional equipment); filming with camera speeds up to 64 frames per second is classified as slow-motion photography. The effect of slow motion is produced upon projection. The technique makes it easier for the viewer to distinguish the phases of phenomena and processes observed on the screen. It is also used in hand-held photography and photography from a moving motor vehicle or boat; in such applications the image on the screen becomes more stable and does not appear to jump about. Slow-motion photography is usually accomplished with ordinary professional or amateur motion-picture equipment with an expanded range of filming speeds.