Camera Lens

Introduction
Lens are the most important component of CCTV Cameras, typical lens varied with Focal Length, Aperture and Angle of the Field of view. Selecting the appropriate lens is the critical step in constructing a complete surveillance system.

Focal Length and Angle of the Field of View
Lens with a shorter focal length monitor a nearer object more clear than that with longer focal length. In contrast, lens with longer focal length can take a more distinct image than that with shorter focal length. However, the angle of the Field of View is greater with a short focal length and will show a wider picture. The angle of the Field of View is smaller with a long focal length and will show a narrower picture. Here are the example of lens with different focal length.
 
Camera Lens

Adjustment of Aperture
As CCTV Lens do not like human eyes, they need appropriate aperture size to take optimum light level for the exposure of image. There are three kinds of lens available: Fixed Manual monofocal lens, Manual monofocal lens, and Auto iris monofocal lens.

Basic CCTV Lens

Model
Type	Fixed iris monofocal lens	Manual Iris monofocal lens	Auto Iris monofocal lens
Introduction	- Iris control is fixed - Widely used for indoor    purposes - Inexpensive	- Manual adjustment    needed for iris control - Widely used for indoor    purposes - Little expensive than    Fixed one	- Adjustment of iris is   automatic - Widely used for in/out   door purposes - More expensive than   Fixed one
Focal Length Selection	2.8/4/6/8/12/16/25 mm	2.8/4/6/8/12/16/25 mm	2.8/4/6/8/12/16/25 mm
Mount	CS Mount	CS Mount	CS Mount
Adjustment	Focal Length	Focal Length/iris	Focal Length
Warranty	1 Year	1 Year	1 Year
Advanced Camera Lens
Model
Type	Fixed iris monofocal lens	Manual Varifocal lens	Motorized Varifocal lens
Introduction	- Automatically switch to   IR under low light   conditions - Widely used for indoor    purposes	- Manual adjustment    needed for iris and    varifocal length control - Widely used for indoor    purposes	- Adjustment of iris and   focal length is   automatic - Widely used for in/out   door purposes - Expensive
Focal Length Selection	2.8/4/6/8/12/16/25 mm	3.5-8 mm/ 5.5-33 mm	3.5-8 mm/ 5.5-33 mm
Mount	CS Mount	CS Mount	CS Mount
Adjustment	Focal Length	Focal Length/iris	Auto
Warranty	1 Year	1 Year	1 Year
For More Information  - Professional Color CCTV Camera Datasheet