Since prices have dropped significantly, many homeowners today opt for color cameras over black-and-white models. For security and evidence purposes, color cameras are better. It’s difficult to tell police to look for a “brown-haired man wearing a black leather jacket” when you can’t make out the colors.
While black-and-white cameras can operate better than color cameras in extremely low light situations, many homeowners use CCTV indoors where there is a lot of natural light. In addition, many high-quality color cameras today can switch to black-and-white mode when necessary, providing both functionalities at one price.
Resolution
Resolution refers to how detailed a picture the camera can see. The measurement to look for is horizontal TV lines (TVL). A normal surveillance camera picture is around 350 TVL to 400 TVL, with high resolution getting up to 480 TVL or 500 TVL. Vendors can sometimes upgrade resolution for as little as $50.
For home CCTV needs, cameras with 420 TVL are best. Go lower than 420 TVL and you sacrifice picture quality; go higher and you may not be able to generate enough light to justify the purchase.
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You also need to make sure your entire system is capable of supporting high resolution. If your DVR records 350 lines and your monitor displays 400 lines, upgrading to a camera with 500 lines would be a waste of money. Ultimately, the small cost to upgrade your camera may be multiplied by the costs to upgrade other equipment.
Note: Do not be impressed by pixel measurements in the hundreds of thousands. TVL is a more consistent measurement.
Other specs
Signal to noise ratio (s/n) indicates how much “signal,” or actual picture information, the camera transmits, as opposed to “noise,” which comes across as static. An s/n ratio of 40db indicates that the signal is 100 times the noise, which results in an acceptable picture with some fine grain or snow. In contrast, 30db results in a poor picture while 60db produces an excellent picture with no static visible. Keep in mind that noise can be introduced by other components in addition to the camera.
Sensitivity to light is measured in lux. A sensitivity of 2 lux means the camera can see fairly well by the light of a 40W fluorescent bulb; 0.5 lux outdoor security cameras can make out images outside on a dim night. Your needs will depend on the lighting in the area being filmed, but lux ratings should not be the most important aspect of your camera decision.
