Selecting the appropriate lens allows you to optimize the surveillance coverage of your camera. If you want to observe a limited area with your security camera, like an entrance or exit, you should choose 12mm lens, it makes a narrow view and objects are closer. The Jinyuan Optics 12mm Fixed Focal 3 Megapixel Lens is special designed for HD dome cameras and box cameras. It can support 1/2.5 inch and smaller CCD sensors. On a camera using a 1/2.5inch type sensor, this lens will yield a 32° angle of view. It is factory set for a fixed focal length to achieve the optimal field of view and provide your camera with a high image clarity. The mechanical part adopts a robust construction, including a metal shell and internal components, making the lens suitable for outdoor installations and harsh environments.