What do you mean by SLR, wide angle and telephoto in digital cameras?

SLR: A single-lens reflex camera with viewfinder system is called a SLR camera. Wide angle: refers to the wide-angle lens of photography. Wide-angle lens is a kind of lens, which has a wider angle of view and shorter focal length than general lens, and is often used to shoot objects with larger area. A lens smaller than 50mm has a short focal length (wide angle). The lens between 50 mm and 135 mm is medium focus, and the lens larger than 135mm is telephoto.

Telephoto telephoto means that the lens can extend to a relatively long distance, such as 10 times, that is, the lens of 35 mm extends to 350 mm, which is convenient for capturing distant scenes; Short focus generally refers to near focus, or macro, that is, you can shoot the scenery close to the lens, which is generally used to shoot the words in the book; Focusing is focusing, which makes the scene on the lens or display clear.