Difference between slow door and frame extraction

The difference between them: slow-door and time-delay photography is a method of taking pictures, low-speed photography is a method of taking videos, and frame extraction is a means of later video.

The so-called slow door means that the shutter speed is very slow and the exposure time is very long. It can make the water flow smooth and delicate, the car can shoot the light track at night, and the cloud can shoot the feeling of drawing. Video frame extraction is to extract several frames from a video at regular intervals, simulating the process of taking a photo at regular intervals and splicing it into a video (that is, low-speed shooting). It will feel different from simply fast-forwarding.

The visual effect of the photo taken by the slow door is very shocking, because it is a picture that we can't see, which is very cool. Time-lapse photography is essentially an exposure at a certain time interval, and the images formed by each exposure are superimposed (synthesized) on the same picture. If it is a film machine, it is a negative that has been exposed many times at the same time interval.