CCTV Camera Lens
The Focal Length of a CCTV Security Camera is measured in mm. For example, a short focal length (e.g. 2.5mm) = a wide angle of view and a long focal length (e.g. 16mm) = a narrow angle of view. For a camera covering the general area inside a shop we would usually use a 3.6mm fixed lens, whereas in a petrol satation, we would use a 5-50mm vari focal, auto iris lens. This will give us the option to zoom the focal lens near and far to suit the best viewing angle.
Some examples of CCTV Lenses are below;
Fixed Board Lens
This type of lens is usually found in a standard dome camera, bullet camera or covert camera.
Vari Focal Lens
This type of lens is found in some internal domes or on a traditional/box camera. The lens can be adjusted to suit the focal lenth required. Some popular sizes are 2.8-11mm, 3.5-8mm, 4-9mm and 5-50mm although different sizes are available. This lens can also have an Auto Iris function which is ideal for situations where the lighting levels change – ie external cameras.
Zoom Lens
This is used in a Traditional Housing or PTZ camera, the lens is controlled manually or by an IO board. The lens can change its focal length by zooming in or out. Ideal for larger installations such as Freeway Cameras, Petrol Stations or Industrial Yards.