Excuse me, what function does AF-A.AF-S.AF-C. in SLR cameras stand for?

AF-C: continuous focusing, suitable for shooting moving objects;

AF-S: single focus, suitable for shooting still objects;

AF-A: Let the camera automatically select AF-C and AF-S modes.

Extended data:

SLR cameras (SLR cameras) are also called SLR cameras. Refers to a camera that uses a single lens, through which light shines on the reflector and takes a view through reflection.

Compared with paraxial cameras, SLR cameras have the advantage that what you see is what you get, and the imaging angle in the viewfinder is the same as the final film. However, compared with paraxial camera, the back focus of SLR camera lens should be able to image at the focal plane of reflector and photosensitive element at the same time, and false focus must be generated before imaging at the focal plane, which makes the structure of SLR camera optical lens more complicated and larger, and the imaging effect is not as direct and transparent as paraxial camera. At the same time, the volume of the "reflector" should be large.

It only has one lens, which is used for taking pictures and framing, so the parallax problem is basically solved. When taking a view, the light emitted by the object is focused by the lens, reflected by the oblique mirror to form an image, and then reflected by the "roof prism" raised at the top. Photographers can observe the scene through the eyepiece, and it is the same image as the scene, which is convenient for framing and focusing.

Single-lens reflex camera can change all kinds of matching wide-angle, medium-focus, telephoto or zoom lenses at will, and can also be equipped with close-up lens, extension ring or telescopic leather cavity as needed. In short, any scene that can be seen clearly from the viewfinder can be photographed by the camera.

A simple single-lens reflex camera using 120 film generally does not need a pentaprism (such as Great Wall DF-4) and can directly focus on the ground glass. Mid-to-high-end single-lens reflex cameras can also be replaced by overlooking viewfinders (such as Zhujiang S-20 1, Nikon F3), so they can also be used for low overhead or inverted viewing just like dual-lens reflex cameras. This is one of the reasons why the single-lens reflex camera gradually replaces the double-lens reflex camera.

References:

Baidu encyclopedia-SLR camera