Auto Focus is a method of using the principle of object light reflection to receive the reflected light by the sensor CCD on the camera, and driving the electric focusing device to focus through computer processing. It is called auto focus. It can be divided into two categories: active and passive.
It has the following three characteristics
1. Automatically determining in some way the subject being photographed by the photographer;
2. Measuring the distance between the subject and the photosensitive element of the camera in a certain way;
3. The driving motor pushes the focusing device of the lens to the corresponding distance scale.
