Tips for choosing the right CCTV camera lens
The specifications for the lens of your CCTV cameras may depend on various factors:
Focal length: The shorter the focal length, the wider the angle of the picture covered will be. The required focal length for your security camera can be calculated as the distance from the object to be focused multiplied by the constant of 4.8, divided by the horizontal or vertical area.
Focal length (L) = Distance (D) × 4.8/ Area (A)
Depth of view: this is the distance within which the various objects in a frame are in focus. A frame with a larger depth of view will focus all the objects in view, whereas one with smaller depth would concentrate on a smaller area.
Iris type: Iris is the adjustable aperture used for regulating the amount of light coming through the lens. The more the aperture is opened, the brighter the image will be. Automatic iris lenses are those that can be controlled electronically. They are essential for outdoor conditions where the intensity of light varies. Manual iris lenses on the other hand should be regulated manually to set the aperture. They are generally sufficient for areas with fixed lighting conditions like shopping centres and offices.
Lens Mount: The two mounts generally available for CCTV camera lens are C and Cs mount. The basic difference between the two is that, the Cs lens should be mounted slightly closer to the image sensor than the C mount lens. The C mount lenses have longer focal lengths.
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Tags: cctv cameras, cctv security, cctv systems, security cameras