How does a SLR camera work?

The whole process of SLR is a single-lens reflective viewfinder. Single lens means that the photographic exposure light path and the framing light path share the same lens, unlike the paraxial camera or the double-reflex camera, the framing light path has independent lenses.

Reflection means that a plane mirror in the camera separates the two light paths: when taking a view, the mirror falls, reflecting the light of the lens to the pentaprism and then to the viewing window; When shooting, lift the reflector quickly, and the light can shine on the film or photosensitive element CMOS or CCD.

The SLR has only one lens, which is used for shooting and framing, and 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.

When shooting, the mirror will bounce up immediately, the lens aperture will automatically shrink to a predetermined value, and the shutter will open to make the film sensitive; After exposure, the shutter is closed and the aperture of the mirror and lens is reset at the same time.

Extended data:

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.