Mechanical structure and principle of automatic focusing lens for camera
Ultrasonic ranging method, which is based on the ultrasonic wave in the digital camera and the time between the subject of distance measurement. Digital cameras are equipped with ultrasonic transmitting and receiving device, when the ultrasonic vibration generator for ultrasonic, ultrasonic to the subject, is the receiver's perception of return immediately, and then by the integrated circuit according to the ultrasonic round-trip time to calculate the focusing distance.
The principle of the infrared ranging method is that the camera takes the initiative to emit infrared light as the distance measuring light source and the geometric relation between the infrared LED, and then calculates the focusing distance.
From the basic principle, AF can be divided into two categories: one is based on the camera and photographed location AF target distance between measurement and another is based on the focus screen clear focus imaging detection.
