What is a slow shutter in photography?

The "shutter" of the camera is just a name, which does not mean fast, but a function name for setting the length of time, so the slow shutter does not conflict.

Shutter is called shutter because taking pictures is actually a process of collecting light through exposure, and shutter is the time needed to collect light. Slow down the shutter just to make the process of collecting light longer.

Because when the light is dim, we can collect more light in the process of photo imaging by extending the shutter time, so as to brighten up.

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