How does Nikon d7000 measure light?

Nikon d7000 photometry method: press and hold the focus switch close to the left-hand bayonet, above the AF/M lever, and then dial the front dial of the fuselage until the focus is displayed as the middle one on the shoulder screen. At this time, the camera becomes a single-point autofocus. At this time, use the arrow keys to set the focus position, which is exactly the position of the face in the composition. A camera is a kind of equipment that uses the principle of optical imaging to form an image and records the image with a negative. This is an optical instrument used for photography. In modern social life, there are many devices that can record images, all of which have the characteristics of cameras, such as medical imaging equipment and astronomical observation equipment.