What is the concept of a shot in a movie? How many seconds is a shot?

Subjective shot: the camera's viewpoint directly represents the shot taken by people's line of sight. With strong subjectivity and emotional color.

Objective: As a bystander, the camera describes the external things through the lens.

Indirect shooting: the lens does not directly show the characters, events and scenes themselves, but only shows the reflection or limited part of the objects, thus creating a special atmosphere and setting up drama suspense.