A few low-end cameras take such measurements through a separate window and, therefore, are not as accurate. The number of manual exposure controls varies from camera to camera. Super-8 cameras are equipped for recording audio onto the magnetic track that is present on sound film. Additionally, a magnetic sound stripe can be applied to silent film after it is processed to allow for post-production audio recording. T he normal running speed for silent movies is 18 frames per second, and sound movies move through cameras and projectors at 24 fps.
Some cameras can shoot at other speeds as well.
My Sankyo EM-40XL camera can shoot at 36 fps. When film shot at this speed is projected at 18 fps, images appear to move at half speed. The most common use of this feature is for producing animations. An intervolemeter allows frames to be shot at timed intervals. For example, filming a sunset at one frame per minute will speed up the action of the setting sun when the film is projected at normal speed.