What does the movie mean by 24 frames per second?

The speed of film rotation in a movie camera. Usually calculated in frames per second (fps), the normal shooting speed is 24 frames per second. The standard projection speed is 24 fps (24 frames per second). In addition, there are three speeds:

In Europe, the electrical frequency is 50 Hz, which becomes 25 fps to match the video signal; Silent 16 cm film is18 fps; Some 8 cm is also 18 fps. Unless it is necessary to use 25 fps, it is best to set the rotation speed to 24 fps, because that is the standard rotation speed of the sound film and applies to all peripheral devices. Only when the speed of the camera is consistent with the speed of the projector, the action on the screen is natural and normal.

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When the camera rotates faster, more frames are taken every second. If the projector displays at the original speed instead of adjusting the speed, slow motion will appear on the screen. On the contrary, if you slow down the camera, say, 8 fps, and the projector still keeps its original speed, the action on the screen will be three times faster than before, which is called fast action.

After the camera changes speed, the exposure time must be adjusted accordingly. The correct numerical value can be obtained by using the operation formula mentioned above. Generally speaking, if the rotating speed is doubled, the exposure of 1 step will be gone.

The speed limit of a general camera is 64 fps, and a high-speed camera can reach a faster speed.

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