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  • Wuxi Kinglux Glass Lens Co.Ltd
  • ADD:No.286,Changjiang North Rd,New Dist,Wuxi,JS prov,China
  • Tel: 86-510-66759801
  • Fax: 86-510-84602998
  • Mobile phone: 86-18168862789
  • E-mail: ledglasslens@163.com
  • Contact person: Huimin Zhang
  • Why are there LEDs around a CCTV camera?
    May 18, 2018

    The LEDs are not normal LED at home, they are IR LED which give red light at night and turn off at day time. There is a light sensor under the camera lens which control the LED turning on or off. LED lighting works much better than traditional lighting solutions, such as lower energy consumption and Superior quality illumination.


    But the LED light as the photo shows is just for small CCTV camera, some PTZ dome or big cameras used on street or in campus, it will need some huge or professional CCTV LED.

    Or smaller one as the picture shows below


    The digital CCTV camera is like eyes of human and it also need to work at night, so the LED need to provide different wavelength from the sunshine. There about three kinds of range:

    • 715-730nm - overt IR, produces a red glow like a red traffic light.

    • 815-850nm - semi-covert IR with a faintly red glow only just visible.

    • 940-950nm - covert IR invisible to the human eye.

    Infra-Red light can be used to provide discrete or covert illumination for CCTV; to minimise light pollution; or to provide very long distance illumination. IR can be used with monochrome and day/night cameras. NB. As IR becomes more covert it becomes more difficult for the camera to see and consequently distances are reduced. 940-950nm IR should only be used with highly sensitive cameras fitted with high performance lenses. Focussing is also more difficult at those wavelengths as lenses start to operate more inefficiently with 940-950nm.

    Besides these IR LEDs, there are some white light LED for CCTV too, they are always used to illuminate an area for the CCTV system; improve the overall level of illumination for key personnel; provide a welcoming environment for authorised personnel; and to deter crime by illuminating a secure area on intrusion; White Light can be used with monochrome, colour and day/night cameras.

    When we talk about the light of LED, it always means the illuminance which is a measure of how much the incident light illuminates the surface. So some guy tell you the LED in 8 Lux is lighter than someone in 4 Lux. But there is also a the Inverse Square Law we need to notice.


    The inverse square law describes how the intensity of a light is inversely proportional to the square of the distance from the light source(the illuminator). Light obeys the inverse square law so to fully understand the way that light travels, and the resultant impact on CCTV systems, some understanding of the inverse square law is required. As light travels away from the point source it spreads both horizontally and vertically and therefore intensity decreases.

    The inverse-square law explains how light intensity reduces over distance but can also be used to calculate how many additional illuminators are needed to achieve specific increases in distance.

    Calculating how many illuminators are needed to cover a given distance:

    When you chose the LED for CCTV camera, please notice these aspects:

    1) Infra-Red or White-Light?

    Identifying the purpose of the system will point to the type of light to use.

    Infra-Red light provides greater distance, a varying degree of invisibility (depending on the exact wavelength) and no light pollution. Infra-Red is light designed only to be used by CCTV cameras. White-Light provides the opportunity to illuminate an area for pedestrians, staff or vehicles in addition to the CCTV system. It can also be used as a visual deterrent when turned on if an intruder is detected by a PIR.

    2) Angle?

    The illumination should ideally match the angle the camera / lens is set-to in order to provide best performance. If not, and too narrow an illumination angle is chosen, the camera will simply see a bright spot in the middle of the scene and the contrast between light and dark areas on scene will be too great to provide high quality images. Illumination which is too wide wastes energy and reduces achievable distance.

    Note: The adoption of vari-focal lenses has caused difficulty in specifying lighting. With vari-focal lenses the exact FOV is often only established on site through trial and error making exact matching to fixed angle lighting impossible in advance. The latest vari-focal lighting allows the output angle of an illuminator to be adjusted on-site to match the set-up of a vari-focal lens.

    3) Distance?

    After selecting the angle, the next consideration is distance. How far should the lighting illuminate? Installers and specifiers should be aware that as angle increases, distance decreases.

    4) Camera and Lens Considerations

    The exact performance of any illuminator in a CCTV system is dependant upon the camera and lens combination used. For best results a high sensitivity camera (for IR projects an IR sensitive camera) should be used with a high transmission lens. Generally a CCTV imaging system (camera, lens, illumination) is only as good as its weakest link.