What is the principle of camera long exposure?

In fact, photography is essentially a two-dimensional projection of the scene, so time and space are fixed in the photo, just like you are using strokes. If you are given enough time, the content on the canvas can be very rich. If there is not enough time, then the content is only a part. As for this trajectory, if you still can't understand it, just put your finger up and shake it quickly in front of your eyes, and you should be able to see the trajectory of your finger. This is because some functions of human eyes are similar to cameras, and the speed of processing images is limited. When the object moves too fast, the image seen by human eyes is similar to long exposure, and the motion trajectory of the object will be recorded.

As for the operation level of cameras, in most cases, it is feasible to expose one camera for a long time or shoot multiple cameras for reorganization.