Monitor the camera's focal length how to choose?
Third, because the lens focal length and horizontal perspective is inversely proportional, so both want to see far, want to see wide and clear, it can not be achieved at the same time. Each focal length of the lens can only be in a certain range to achieve the best monitoring effect, so if the monitoring of the distance and a larger range, it is best to increase the number of cameras, or the use of electric zoom lens with PTZ installation , Of course, this for the civilian use, some expensive, and practical will not increase greatly.
Second, in the choice to buy surveillance cameras at the same time, for the practical application is also essential, such as civilian-level surveillance cameras, in the same product will be divided into 3.6mm, 4mm, 6mm, 8mm, 12mm and so on different specifications of the lens indicators. These are the user to measure the size of their own needs, such as the use of 3.6mm lens, this is wide-angle lens, look at the scope of a wider, suitable for small space (elevator, etc.), often in open space, wide-angle lens may not be able to See the face, in order to see the face you need to choose the focal length and then some of the larger lens, the so-called telephoto lens, more suitable aisle or corridor, etc., of course, choose how much focal length of the lens have to see the distance to be monitored The. The focal length is bigger, and the range of images you want to see is smaller than you see now.
First, choose to monitor the camera lens also pay attention to the focal length of the lens, the focal length is actually the perspective of the problem, the focal length of different perspectives are also different.
