The lux rating you see on many security cameras and hidden cameras is the metric unit measurement of the amount of light that falls on a an object being photographed or recorded.
Lux is the European equivalent of the British foot candle or lumen. This means 1 lux is the amount of light that will fall on 1 square meter of surface area that is 1 meter away from a single candle. For example 10 lux would be the amount of light produced by a ten candles 1 meter away.
If you have a camera with a 1 lux rating that means it should be able to create a visible image by the light of one candle that is about 3ft. away from what is being photographed or videotaped.
Distance affects Lux
Lux is a way to measure light based on the light produced by a single candle. However candles or light bulbs create light and radiate that light out in all directions. If the subject of your video moves further away from the originally light source the amount of light falling on your subject decreases because the fixed amount of light is spread over the larger area.
If you double the distance of your subject from the candle or light source you might think you will decrease the available lux by ½ . In fact you really reduce the available light to only ¼ of the original lux rating. Move the subject 4 times away from the original light and you receive only 1/16 as much light. The decrease is exponential.
Surface areas affect Lux
Lux is a measurement of the light that falls on the subject. But your camera sees and records the light reflected off your subject. Reflected light is what bounces off your subject and is captured by your camera's lens. Bright and highly reflective objects will produce better images in low-light conditions, dark non-reflective of checks will not.
Lenses used in night-vision cameras
A security camera with superior lenses will provide better reproduction than one that relies on electronic enhancement of the digital recording. Superior lenses get more light from the surveillance area to the digital imaging sensor (CCD) inside the camera unit because they have fewer imperfections and impurities. High quality lenses also give you the sharper detail that, less distortion, and more vibrant colors.
Ideally, larger lenses grab more light and create clearer pictures But this must be balanced against the need for compact and unobtrusive cameras.
The number of lenses and (CCD) chips also affect video quality. Some cameras use three chips each with its own lens and divide the incoming light into its three component colors red, green, and blue using a prism. This is a very efficient technique and very little light is lost during the course of splitting. However prisms are not usually practical for highly compact security cameras.
Electronic enhancement of video
Many security and cameras rely on embedded software to digitally amplify what little like comes through the lens. This is an inexpensive technique but results in extreme graininess and lots of video noise.
Using infrared light
Infrared light can be seen and recorded by your camera but cannot be seen by the human eye. This is very important when using security cameras in the dark. Infrared equipped security cameras will be able to record in situations with zero light available. Your video will be green tinted.
Using the low frame rate
Another way to enhance or improve the ability of your recording system to capture images in low-light situations is to reduce the frame rate. Your recorded video will be more choppy but will capture far more digital information on each frame.
Conclusion
Try to keep all these various factors in mind when you read the cameras lux rating.Ask yourself if the camera is rated at 1 lux or less because of its superior lenses or its electronic circuitry. You will find that superior lenses will win out over the electronics when it comes to low-light recording or surveillance.
