Network Security Camera | Types of Lenses

Network security cameras use one of three types of lenses. They are either fixed, varifocal, or zoom lenses and each has its own strengths over the other types. The fixed lens in a network security camera offers only one field of view because the focal length is fixed, usually at 4 millimeters. The field of view is either telephoto, wide angle or normal.

Varifocal lens offer different fields of view because the focal lengths are not fixed and can do a range of lengths from 3mm to 8mm. The field of view has to be adjusted manually by the user and the lens requires manual refocusing whenever the camera's field of view is changed.

The automatic version of the varifocal lens is the zoom lens. It also allows for different fields of view but the lens does not need to be refocused when changing the field of view. The zoom lens in a network security camera also can hold focus within a range of focal lengths. The adjustment to the lens can be done manually or by remote control and the zoom capability in the specifications refers to the range between the network security camera's longest and shortest focal length.