How far is the focal length of 3.6mm?

3.6mm viewing angle is 70 degrees, illumination distance is 0 to 5 meters, 4mm viewing angle is 69 minutes and 9 degrees, illumination distance is 0 to 6 meters, and 6mm lens is 42 minutes and 3 degrees away from 20 meters. Different lens mm numbers represent different focal lengths. The greater the number of mm, the greater the focal length of the lens and the farther the irradiation distance, but the smaller the viewing angle.

A camera is a device that records images by using optical principles. The invention of the camera was originally used for the production of movies and TV programs, but now it has become popular. Just like cameras, early cameras needed to use negatives (that is, video tapes) for recording, but now the invention of digital cameras enables images to be stored directly in flash memory. Newer cameras directly store image data in the hard disk of the fuselage, which can not only record dynamically, but also shoot statically, without bringing a digital camera at the same time. Family portable camera is light and easy to operate, and it is almost a necessary household appliance.

An optical photographic instrument for recording images of high-speed moving objects. It records the flying posture and events of harmony at a high photography frequency. Intermittent and compensated high-speed cameras are often used in flight tests of rockets and spaceships. The film of intermittent high-speed camera is controlled by the film grasping mechanism, and the film is not moved when shooting, and the exposure is controlled by the shutter. After exposure, the film moves by one frame. The film of the compensation high-speed camera is in continuous motion. When shooting, the target and the film are kept relatively still by the compensation mechanism, and the exposure is controlled by the shutter. Intermittent cameras are used to photograph rocket ignition, flame condition, plug falling off, longitudinal and lateral drift of the rocket when it leaves the frame, etc. The shooting frequency of 35mm synchronous intermittent camera shall not exceed 300 frames per second. The shooting frequency of compensated high-speed camera ranges from hundreds to thousands of frames per second, and it is continuously variable. It is used to photograph the secondary ignition and stage separation of rockets, and also to photograph the encounter of rockets. High-speed camera consists of optical system, shutter, film feeding and winding mechanism, frame and time control mechanism. It can be fixed or installed on the tracking frame to shoot flying targets manually or automatically.