Nature documentaries - the ones you see on TV - I love them. I have learned SO much from them. Like this fact: compared with other species, human beings have a very restricted sense of vision. We 'see' only a tiny fraction of what can be seen - we are blind as a bat when it comes to seeing in the infrared or ultraviolet range of light.

But the good news is that we human beings have access to technology that allows us to make up for our own natural limitations. And a good example of this type of technology are infrared security cameras. Infrared security cameras, unlike our own eyes, can detect images in the environment using light in the infrared wavelength spectrum.

And what makes infrared security cameras very useful for home security is that with them, we can monitor areas with absolutely no visible light (what the professionals call a Lux 0.0 environment). Business and industry have been big users of infrared security cameras for years - with them they can monitor a darkened warehouse or bank vault area after business hours, when the lights may be turned out.

In the home, we can use infrared security cameras as well: perhaps in the downstairs living room, or a darkened external garage area or long driveway outdoors. They are ideal tools to detect the presence of all sorts of intruders -- even stray animals such as deer, stray dogs and even rodents.

The really nifty thing about infrared security cameras is that they can be located in the darkest of environments, yet still provide a camera image. And this is certainly bad news for the professional thief, who typically seeks out darkened rooms and homes for a break-in. They assume that the darkness will make it impossible for them to be detected. But infrared security cameras will catch them every time!

Make sure that any infrared security camera that you purchase has an 'auto-scan' function. When a camera is set to auto-scan, it will move back-and-forth, covering the same area repeatedly. So you can set up several of these cameras to monitor a specific area continuously. In this way long and large areas, such as hallways, driveways and entrance lobbies can be monitored effectively.

Infrared security cameras do not rely on light from things like a light bulb, or the light of the moon or sun. Instead, they generate their own light. Some models shine a beam of infrared light from the camera unit itself - like a James Bond high-tech flashlight. Other infrared camera models use a separate light source to illuminate an area (you can't see that light, of course). When the light is operational it shines in the area to be illuminated, and the infrared camera uses that light to capture images.

Many folk confuse infrared security cameras with 'low light' cameras. Low light cameras, in and of themselves, do not use infrared light - they use normal daylight, but can function with very small amounts of such light (think of light very early in the morning, or at dusk). One weakness in most infrared security cameras is that they do not work well in large, expansive areas - so if you have a large area to monitor, like a warehouse or big garage, you may need to use several. Some models are dual-function: they work like regular security cameras during the daytime, but switch over to infrared functioning when necessary.