What’s the surveillance camera lens focal length?

When people choose the surveillance camera, (like especially home security camera, the motion activated camera) they need to know how to choose the suit camera, and they should know the parameter of the camera. Especially, lens focal length. What’s the meaning of the lens focal length?

In the surveillance camera. When the lens focal length (unit: mm) is smaller, it will get a wider field of vision, but the image of the object in the picture is smaller. On the contrary, the larger the focal length, the narrow the field of vision, and the clear image of the object in the picture. Effective Object Distance

Camera lens focal length, surveillance angle and distance relevance:

Lens focal length	2.8mm	4mm	6mm	8mm	12mm	16mm
Surveillance Angle	75°	70°	50°	38.5°	26.2°	19.8°
Surveillance Distance	3m	10m	15m	25m	40m	50m

In physics, the focal length is a measurement method used in an optical system to measure the aggregation or divergence of light. It refers to the distance from the optical center of the lens to the focus of light aggregation when parallel light incidence.

Optical systems with short focal lengths have a better ability to concentrate light than optical systems with long focal lengths. Short to say, the focal length is the distance between the focal point and the center of the optical lens.

Do you know how to choose the security camera lens focal length then? It’s one important specification when choosing the home security camera. Also, we should consider the camera resolution, pixel when choosing the security camera. Are you clear of the pixel? We have an article about it. Welcome to your comment and inquiry.