In monitoring and surveillance applications, camera sensitivity is one of the most important factors in obtaining an adequate picture in low light conditions.

Minimum illumination (Camera sensitivity)- is the minimum light level needed to achieve 50% or 100% video output level when the camera is at maximum gain and the lens iris is fully open. Camera sensitivity varies from camera to camera. For example, the Sony SSC-DC393 color camera operate at a minimum illumination of .35 lx / .7 lx/ 3.5 lx and the Sony SSC-M383 B/W camera operate at .04 lx/ .07 lx /.3 lx depending on the camera settings. A camera with a min illumination of .05 lx can actually see better than the human eye at night. To get an idea of illumination please refer to the following chart for average lux levels throughout the day.

Scene Illumination	Lux
Clear Sunlight	30,000 to 100,000
Overcast Day	3,000 to 10,000
Sunrise/Sunset	500
Twilight	5
Full Moon	0.03 to 0.3
Starlight	0.0007 to 0.003
Overcast Night	0.00002 to 0.0002

There are several ways to increase the lux or area light to enable a camera to capture the desired images. Infrared devices can improve visibility and detail for cameras in low light. Street lamps and other additional sources of direct/indirect light can improve illumination for the camera; many of these can be used without being obvious as to their purpose.

Another feature to look for in a camera is called BLC (Backlight Compensation). BLC automatically compensates for the subject matter casting shadows, making the subject easy visible with improved object recognition. This is a newer feature in security cameras and is available in several of the new Sony cameras like SSC-DC393 and SSM-383.

Resolution is another specification to consider when picking a security camera. Camera resolution is a measurement of the camera’s clarity. A camera’s resolution is determined by the number of horizontal video lines (like 330 or 580 TV Lines) that the camera needs in order to reproduce the desired image. The higher the resolution, the sharper the image will be. Although resolution is important when considering which camera to purchase, the quality of the camera’s components are much more important.

For example:
The sensitivity of Sony cameras using the Exwave HAD technology (SSC-DC393 and SSC-M383) is well over twice that of the cameras using Sony Hyper HAD technology. The Hyper HAD sensor structure has an OCL (on chip lens) located over each pixel. The results is that light is concentrated on the photosensor areas and the sensitivity of the camera is improved. The Exwave HAD takes the Hyper HAD technology a step further. The OCL of the Exwave HAD is a nearly gap-less structure, eliminating the ineffective areas between the microlenses. This enables the hole accumulated layer to receive the maximum amount of light. Moreover, the smear level of the Exwave HAD technology is reduced 1/50th that of the Hyper HAD technology. This leakage is dramatically reduced because the improvement of the unit cell structure minimizes the unnecessary reflection of the light onto the CCD surface.

If you would like more information or would like to talk with a salesperson please contact the office nearest you or email sales@vmivideo.com with your request (please include the article name, and your contact information).