twh@mb2c.UUCP (Tim Hitchcock) (06/11/84)
Super 8 cameras (good ones) record sound movies at 18 *OR* 24 fps. Movement with/without sound does not look good at 18 fps. 24 fps is too slow, but not as noticeable.
davew@shark.UUCP (Dave Williams) (06/11/84)
Silent movies were shot at 16 fps which gave a resonably jitter free picture. When sound recording came along it was found that the optical sound system could not record a sound above 4500-5000 Hertz because of the size of the film grain. While this would be good enough for speech, it was not good enough for music and sound effects. The film speed was increased to 90 feet per minute (24 fps) to get better sound response. Optically recorded sound tracks generally begin rolling off at 7000 Hertz. It was found that this was an acceptable number as many of the movie houses of the time had very poor acoustics and higher frequency response only added to the problem. Many of the movie houses were long and narrow (They were called shooting galleries) and standing wave problems were common. When stereophonic sound recorded on magnetic film came out in the fifties many of these problems resurfaced and the theaters either had to do some acoustic treatment to their facilities or roll off the sound at about 7-8000 Hz. Incidently magnetic film is the correct term as it was either magnetically striped 35 mm prints or a seperate 35 mm acetate film base coated with magnetic material. The sound track was run through a special playback unit sync'd up with the projector.