How to control aperture, sensitivity, focus and exposure in film shooting?

Movies are basically shot on 135 film (at present, there are occasional digital devices and IMAX films). 135 camera shoots 24 frames per second, so the shutter is fixed at 1/50 seconds, and the sensitivity of the film is also fixed at low sensitivity, so the exposure can only be controlled by manual dimming and aperture.

Small aperture is used to ensure a large depth of field when shooting landscapes or people's distant views, so it is necessary to increase the intensity of artificial lighting, and use large aperture to blur the background when shooting middle scenes, close shots and close-ups to reduce the lighting intensity. Before shooting, directors, photographers and lighting engineers should repeatedly study the light intensity, angle, color temperature and so on. .

As for focusing, the middle shot, close shot and close-up figures are all fixed, so focusing is simpler. If you move, you can use the camera slide rail to move at the same speed as the person to keep the focus fixed.