16 Channel DVR Card & 4 Wired Color CCD Cameras Security System ESGV-800V3+FI-101C

Many cameras included a BLC circuit. This circuit is used to help correct an image with more light behind the subject being viewed. Without backlight compensation, the subject appears dark with little detail. Using backlight compensation will reduce the brightness of the light to allow the subject to appear brighter and bring out the details.

Refers to the size of the imaging sensor. Common formats are 1/4", 1/2", 1/3", 2/3", and 1". The size of the sensor directly affects the field of view obtained. When using the same size lens on different format sensors, different viewing areas are obtained. For example, using a 6 mm lens on a 1/3" sensor will give you a 37 degree field of view. Using the same lens on a 1/2" sensor will increase the field of view to 56 degrees and 74 degrees on a 2/3" sensor. It is important to make sure you have a lens that was designed for at least the size of your sensor. For instance, you can use a 1" format sensor on a 1/3" camera, but you cannot use a 1/3" lens on a 1" camera. If you use a lens designed for a smaller format camera, the image will be vignetted. Also, by using a lens designed for a larger format sensor, the field of view will be greater than what is specified.

An automatic iris lens is a lens with a motorized iris that automatically adjusts to only allow a specific amount of light to reach the image sensor. When there is too much light, the iris will close to reduce the amount of light let in. Auto iris lenses are primarily used in applications where light levels vary and it would be impracticable to manually adjust the lens. Automatic iris lenses are generally more efficient than the electronic shutter since they actually control the amount of light reaching the sensor as opposed to simply adjusting the shutter speed.