Principle of telephoto camera lens

The principle of a telephoto camera lens mainly includes optical principles and design features. ‌
Principles of Optics
The main characteristic of a telephoto lens is that its focal length is significantly greater than that of a standard lens, typically between 80 millimeters and 1200 millimeters. The angle of view of a telephoto lens is smaller than the normal angle of view of the human eye, usually between 2 ° and 34 °. A telephoto lens typically consists of a converging lens in the front and a diverging lens in the back. This design is not only used for imaging, but also can increase the focal length without changing the size of the body, thereby improving the length magnification. By shifting the main surface of the image towards the front, the goal of increasing the focal length of the lens group can be achieved.
Design Features
The design features of telephoto lenses include:
Long focal length: The focal length of a telephoto lens is significantly larger than that of a standard lens, typically between 80 millimeters and 1200 millimeters.
Small angle of view: The angle of view of a telephoto lens is smaller than the normal angle of view of the human eye, usually between 2 ° and 34 °.
Lens combination: consisting of a converging lens at the front and a diverging lens at the rear, this design can increase the focal length without changing the size of the body, thereby improving the length magnification.
Application scenarios
The telephoto lens is commonly used to capture objects at long distances, such as sports events, wildlife, landscapes, etc. Due to its long focal length and small viewing angle, the telephoto lens is able to capture details in the distance and can shoot without disturbing the subject.