What is the principle of film shooting and screening?

What visual principles are used in film shooting and screening?

When watching movies, we all feel that a series of activities of people or things on the screen are no different from those in real life. Why do we feel so realistic?

First of all, understand the filming and screening process. The shooting lens has an intermittent device, which stops 24 times per second. As soon as the shutter stops, the exposure opens and the scene is taken into film; When playing, the shutter is closed, the film rotates and moves continuously for 5 seconds. The camera takes 120 pictures, and there are 120 pictures on the film. According to the action sequence, the actions of any two adjacent pictures are slightly different. When these films are shown, they are also opened and closed 24 times per second, and the copied pictures appear on the screen 24 times per second. When the projector is turned on, a picture appears on the screen, and when the projector is turned off, the screen is dark. For such an hour's movie, the screen was dark for nearly half an hour. However, no one feels the alternation of light and shade. What we see is a continuous picture. Why?

People's understanding is a touching phenomenon. If a vertical light band is projected on the screen, and a horizontal light band flashes at intervals, the two light bands form an angle of 90. With the different time intervals of the two light bands, people's perception results are different. When the interval is greater than 1/5 seconds, people see two continuous light bars; When the interval is less than 1/30 seconds, people will feel that the two lights are on continuously at the same time. When the interval is115 seconds, we will regard them as white light moving back and forth in an intuitive range. This is the "motion-like phenomenon", that is, things that are not moving are perceived as moving, and the interval of 24 times per second when shooting and showing makes the still picture dynamic.

Motion-like phenomena are mainly caused by visual afterimages. The feeling caused by external stimuli does not disappear with stimulation, but often lasts for a short time. This feeling is called "sensory persistence". When the stimulus no longer works, this feeling is called "afterimage". Later, there were positive and negative feelings. Looking at a lighted fluorescent lamp for a long time, it turns black after closing your eyes, but when you look at the fluorescent lamp, you close your eyes immediately. This light seems to flash before your eyes. The former phenomenon is negative, while the latter phenomenon is positive. Motion-like phenomena are the result of positive and negative images.

We can feel the real life from the screen by using the visual movement phenomenon and synchronous photographic projection. In addition, the filming and screening of the film are still out of sync. We can see that slow motion is the result of fast beat and slow play. Beautiful shots are often shot several times slowly. All of the above are related to the phenomenon of human movement.