Some video cameras offer frame by frame filming for animation. Film cameras sometimes allow you to rewind the film, and expose it a second image over the previous image recorded, allowing you to do some neat special effects. Some film cameras also film backwards. It is important not to confuse camera speed with film speed. Camera speed is the frame rate at which the camera photographs, in frames per second.
Film speed is the sensitivity of a film to light.
If a film reacts to light very quickly, it is considered fast. If it is not as fast, it is considered medium speed, and if it is very insensitive, it is slow. We can regulate the film's exposure to light in two ways. Most motion picture cameras don't have a variable shutter, so the lens's iris is usually used for this purpose. Slow films are consequently used often outdoors.