What is scanning in photography?

By scanning the object with a light source, the shooting effect is achieved on the basis of long exposure.

Sweeping off is a shooting method that uses a light source to sweep over the subject and uses long exposure light to achieve special shooting effects. This should be distinguished from light painting. Light painting uses long exposure light to paint directly with light source, but there will be no light source in scanning light. It can be understood as: wearing polished clothes on the body with sweeping light.

Scanning light can greatly enhance the ability to understand and use light.

On the problem of sweeping light source: flashlight is the best. But the light source is too concentrated and strong, so it can be covered with a napkin. Generally speaking, two floors are enough. If the flash of the mobile phone can be turned on for a long time, it can be used as a scanning light source.