Digital cameras use image sensors that convert light into electronic signals to take photos.
The difference between SLR cameras is that the optical viewfinder displays the image through the camera lens. The term "single mirror" in the name "single mirror reflection" refers to a single lens that is both used to take photos and serves the viewfinder. "Reflection" refers to the reflection of light. The digital single mirror reflex camera is equipped with a reflector, which guides light from the lens into the viewfinder by reflecting upwards, hence the term "reflective" is included in the name.
The upward reflected light is directed towards the focusing screen of the viewfinder; After passing through the focusing screen, the light continues to pass through the pentaprism or pentaprism and enter the viewfinder's eyepiece window. Therefore, the photographer can directly see the image from the camera lens in the viewfinder. When the shutter release button is fully pressed, the reflector will pop up and the light passing through the lens will directly point towards the shutter curtain. At the same time, the curtain will open to allow light to be directed towards the image sensor, and the camera will take a photo. The shutter then closes and the reflector returns to its original position. Under the linkage of the shutter and reflector, the light passing through the lens can be directed towards the viewfinder focusing screen or image sensor.
Some new digital single mirror reflex cameras can display images through the lens on the display screen. This is what is called "instant framing". During real-time filming, the reflector will bounce up; This will block the light that could have reached the focusing screen, preventing you from composing in the viewfinder.
