How to choose the size of a CCTV lens

•Guidelines

- The smaller the focal length number, the wider the field of view.
Please refer to the following chart. It demonstrates the basic relation between Focal Lengh and angle.


Approximate Horizontal angles of view for CCD Chip Cameras

Focal Length
2/3"
1/2"
1/3"
1/4"
2.0mm
-
-
-
82
2.8mm
-
-
86
57
4.0mm
-
77
67
47
4.8mm
86
67
57
40
6.0mm
70
56
48
32
8.0mm
56
44
36
25
12mm
39
30
25
17
25mm
18
15
12
8
50mm
10
7
6
4

Example 1 - If you have security camera in the office or warehouse and you want to see as much as you can, you should go for 3.6mm or smaller lens (widens view, but will be more distant).

Example 2 - If you want to observe a limited area, like the entrance, you should go for 8mm or bigger lens (view is narrower, but objects are closer).

Calls are always welcome if you need further assistance in determining what kind of security camera lens will best suit your location.