Why does slow-motion photography always flash?

Under the general civil lighting system environment, it is normal for slow-motion photography pictures to always flicker. The frame number of slow-motion photography is too high, which can reach thousands of frames, that is, 1000 frames per second. Apple 6 can reach 240 frames. The lighting system of a normal family is 50 frames, which means flashing 50 times per second.

Human eyes can't feel it, but it's too slow for high-speed cameras, so slow-motion video looks like a flash.

Variable speed photography, changing the frame rate. This means changing the normal speed (24 frames per second). Upgraded photography and degraded photography are variable-speed photography. Its purpose is to show some special effects that can't be achieved at normal speed.

Extended data

A photographic method to change the normal running speed of the film in the camera when shooting. The normal speed of film is 24 frames per second. After shooting, people and things on the screen will run at normal speed when the projector projects at the same speed.

If you want to achieve a special artistic effect to speed up or slow down the running speed of people and objects on the screen, you can use a variable speed motor to slow down or improve the running speed of the film in the camera, and then use a projector running at a normal speed of 24 frames per second to show it. If the speed of photography is less than 24 frames per second, it is a snapshot when showing; When shooting at a rate higher than 24 frames per second, it is displayed in slow motion.

Reference source: Baidu Encyclopedia-Variable Speed Photography