There are a wide variety of lenses which produce different scenes, known as field of view. CCTV camera lenses are designed to address specific surveillance needs. CCTV is also known as surveillance cameras.
What is field of view?
The field of view is the area of coverage of which a camera can view. The field of view depends on the size of the lens. The higher the number, the narrower a view.
This simplified diagram below shows you the sort of coverage you expect from different lens sizes.
2.8 mm is a 90° view
The 2.8 mm lens is a popular choice for static camera surveillance with a wide field of view. One camera can cover a wide area.
Outdoors: the 2.8 mm lens is an effective choice for outdoor used.
Indoors: the 2.8 mm lens is the choice for indoors since it can be mounted in a corner to monitor an entire room.
4 mm is a 60° view
Although the 4 mm lens has more clarity at a further distance, it shows a similar scene as the 2.8 mm. The primary difference is the reduced viewing angle which makes objects appear closer to the camera.
6 mm is a 45° view
The 6 mm lens provides a narrow, detailed distance view. To monitor specific objects, a telephoto lens is used. This would be used for monitoring the entrance to a parking lot, parking garage, or a doorway. It’s also useful for a corridor, especially when combined with corridor format/view technology.
The choice of camera view impacts what we are able to monitor. We will help design the ideal system based upon your specific needs and expectations.
The other factor which affects your field of view is resolution. The higher the resolution provides a clearer image which means details such as license plates and people faces will be more visible and less pixelated.