You walk into a pitch black room, no light anywhere, you see nothing. It’s dark. You turn on your flash light and now you know where you’re going. The flashlight is supplying your eyes with visible light. Voila! You can see.
Cameras work the same way our eyes do. They need light to see. Even if it’s invisible to us, humans.
Light is like a fuel for a camera. It supplies the lens with what it needs to ‘see’. Just like supplying yourself with a flashlight to see in the dark, the same thing needs to happen with your camera or camcorder. The term night vision doesn’t necessarily mean, “I can see in the dark.” What it generally means is, “I can see infrared light.” A camera can’t magically see light that doesn’t exist.
So, if your camera is full spectrum or night vision, chances are it will be able to see infrared and/and ultraviolet light. This is light that is visible to the camera, but we cannot see.
So, now you need to provide the light your camera needs.
In most cases an infrared (IR) illuminator will do the trick for most cameras designated as ‘night vision’ or ‘night shot’.
A Full Spectrum camera has the ability to see even more than infrared. If the camera is developed right, it will see a full range of light (hence the term full spectrum) all the way from infrared and visible light into ultraviolet. I call this ‘night vision PLUS’. A full spectrum cam gives you the ability to see much better in the dark which provides a much higher quality picture and video for evidence. So, for this type of cam you will want a full spectrum light to take full advantage of its capabilities that not only utilizes IR but also Ultra Violet (UV) and visible light. There are also is also a Dual Mode full spectrum light that allows for switching between both as needed. This is quite handy.
For more info, read up on what full spectrum and night vision really means.