Many friends can't figure out the visual distance and monitoring angle of different lenses of the surveillance camera. The following figure clearly expresses the monitoring angle and monitoring distance of the camera lens in the CCTV monitoring system for your reference.

1、 Common lens angle

2、 Use place and angle of surveillance camera lens:
(1) Wide angle lens: the viewing angle is above 90 degrees, which is generally used in places with small viewing distance and large viewing angle such as elevator car and hall; E.g. 2.8mm 2.5mm
(2) The viewing angle is above 60 degrees. It is used in places of about 5 * 5m. It is 3.6mm 4mm
(3) . the viewing angle is more than 50 degrees, which is 6mm for places about 8-10m
(4) . the viewing angle is more than 40 degrees, which is 8mm for places about 10-18m
(5) The viewing angle is more than 30 degrees, 12mm and 16mm for places about 20-30m
(6) . the viewing angle is more than 20 degrees. It is used for places about 30-50 meters. It is 25mm
(7) Telephoto lens: the viewing angle is within 20 degrees, and the focal length ranges from tens of millimeters to hundreds of millimeters, which is used for long-distance monitoring
(8) Zoom lens: the focal length range of the lens is variable, which can be changed from wide angle to long focus, which is used in areas with large depth of field and wide viewing angle range;
(9) Pinhole lens: used for concealed monitoring.
The smaller the lens, the larger the monitoring area, and the image object is relatively small. The larger the lens, the smaller the monitored area (narrow), and the image object is relatively large.
A simple calculation method can be used: the visual distance ÷ 2 is equal to the required lens, and then refer to the viewing angle