CCTV cameras require the correct lens to achieve their full potential. Lens size and type is as crucial to the effective use of CCTV as the camera or any other component of the system. Lens size requires calculations to achieve the desired image. As a basic guide, lens size is calculated from the height of the image sensor used to convert light into digital images (CCD i.e. charge-coupled device or CMOS i.e. complimentary metaloxide semiconductor). Image sensors range in size from 1/6“ to 1”. The larger the image sensor the more light it can capture and the better the images. The height of the sensor forms part of these calculations as detailed below.
1/3” image sensor has a height of 3.6mm, divided by height of subject target of 1800mm and multiplied by distance from the camera at 6000mm.
Corresponding Lens : 3.6 mm /1800mm*6000mm=12mm Lens
The Field of View (FOV) is based on the camera and the lens. By increasing the size of the lens or the focal length, a decrease in the FOV occurs. The perceived view of the object, or how far the object is seen on the screen is improved with higher numbered lenses but narrows the FOV.
