Camera lens size decide the field of long–range surveillance and the angle of the security cameras observation. Generally, the length of fixed security camera lens is from 2.8mm to 12.0mm. Before buying a security camera, the customer should consider paying attention to the length of its lens. The larger the size of the lens, the more narrow and zoomed in the field of view is. The angle of lens section also relies on the image sensor chip. People have used popular sections are one – thirds.
There are two main types of cameras which have fixed or varifocal lenses. It varies on focal length of the lens, the angle of observation and its long range observation. In some technical guides, you do not see the opening angles; however, you could see the focal parameters.