How does a SLR camera measure light?

The metering methods of SLR cameras are as follows:

1. If the average photometry is used, the shot picture can be divided into multiple areas, and each area can be metered independently, and then the average photometry value of the whole picture can be calculated accordingly. Average metering mode is suitable for shooting scenes with uniform light in the whole picture.

2. Spot metering only needs to measure one point. It should be noted that spot metering refers to the area with a framing range of 1%-5%, which is usually in the same position as the focus.

Single-lens reflex camera, also known as SLR camera, refers to a camera that uses a single lens, through which light shines on the reflector and takes a view through reflection. The so-called "single lens" means that the photographic exposure light path and the framing light path share a lens, unlike the paraxial camera or the double-reflex camera, the framing light path has an independent lens. "Reflection" means that the plane mirror in the camera separates the two optical paths. The first SLR camera was developed by 1909. Since 1970s, this technology has been widely used, and SLR cameras have become the new favorites of senior photographers and professional photographers.