What are the differences between various camera lenses?
The focal length of a camera lens is measured in millimetres (mm): 3.6mm, 12mm, and so forth. The number indicates the angle of view of a camera. For instance, a camera with a 3.6mm lens will cover the angle of view of approximately 75 degrees.
There are also cameras with a varifocal lens, for example 2.8 to 12mm. They allow to change the area of view of the camera by zooming in or out (zooming is usually achieved by manually manipulating the body of the camera).
The size of lens determines how much of the area the surveillance camera will be able to cover. Our camera lenses range from 2.8mm to 12mm in size.
A bigger lens will have a smaller / narrower angle of view and display a closer image of the object or area under surveillance.
The approximate angle of view of different lens sizes:
3.6mm – 72 degrees.
6mm – 43 degrees.
4-9mm – 62-33 degrees.
2.8-12mm – 81-22 degrees.
Below is an example of how different sized lenses display the same image: