First CCTV lens calculators were wheel calculators made out of paper.

Such wheel lens calculators are very easy to use. Like in modern software calculators you should select CCD Sensor Format first (like 1/3″) and then you can rotate the wheel and select your desired field of view (FOV).

Picture1. CCTV Lens Calculator

Now these tools made one step forward and jumped from paper to PC. Now there are many online calculators which works in web browser as well as there are some graphical lens calculators, like ours.

Picture 2. Example of graphical CCTV Lens Calculator

Actually it works the same way, but with modern software calculators you can not only calculate field of view or focal length, but also you can visually see the field of view. So you can get a visual model of camera field of view in horizontal and vertical directions.

To check how it works you can download this calculator or see video tutorials.

Explanation:

Camera format (Sensor Size) - Video camera’s CCD chips format; 1/4″, 1/3″, 2/3″, 1″ etc.

Field Of View (FOV) - The width, height or diameter of a scene to be monitored. Usually determined by the focal length of a lens, the sensor format and the distance to the objects.

Focal Length (FL) - The distance from the center of a lens to the focal point (sensor). The longer the focal length, the narrower is the angle of view.