In CCTV and in using security camera terms, LUX can describe how well a camera picks up video in low lighting. The amounts of light picked up by security cameras are defined by LUX (lumens per square meter). A LUX is based on a different unit of measurement for a light which is called a lumen, which is also based on the unit called a candela. The non-SI unit that is used to measure light is called the footcandle. One LUX is defined by the amount of light that is given off by one candle at a one-meter space. A LUX, or also called an lx, is the International System of Units (SI) measurement for the amount of intensity in lights. The LUX rating is defined by the available light intensity in which a camera is able to produce a picture.
LUX Rating Chart
- Sunlight 10,000 LUX
- Full Day Light 1000 LUX
- Well-lit Office 500 LUX
- Comfortable Reading 300 LUX
- Overcast Day 100 LUX
- Dark Day 10 Lux
- Dusk 1 LUX
- Deep Twilight .1 LUX
- Full Moon .01 LUX
- Complete Darkness 0 LUX
A few high-quality CCDs have a good picture all the way down to .1 LUX. If the LUX is lower than that than it will require infrared LEDs on the camera to see through the dark. These cameras are called infrared (IR) or night vision cameras. Most camera’s specifications on their box or website can list the number of LEDs they use on their lens. Customers typically use this and compare it to low light performance. Actually, the type of LED being used can be more important than quantity. Some LEDs produce ten times more light than other LEDs. Some are made so that human’s eyes can’t detect the light being emitted from them. This can make these cameras better for not being detected. The best way to compare IR cameras is by comparing the number of feet the camera can illuminate to how wide their light is spread.
About LUX CCTV Rating
The LUX ratings of security cameras can be based on different areas of expertise. The factors are the lens, the “F stop”, and the sensor chip. The lower the security cameras LUX rating is, the less light is needed to be available for cameras to get a usable video. When you are looking into sensor chip technology and the LUX rating, there should be two types of sensors that are used, CMOS and CCD. CMOS are sensors that require brighter light. This means cameras that are built with this sensor will have higher LUX ratings. The greater the sensitivity is of the cameras sensor and the less light that is needed to produce an image means the more the camera costs.
Aside from the sensitivity of the CCD or CMOS chip, the lens can also affect the LUX rating for the camera. Light can pass through the lenses, and even if the lens seems spotless and clear is can still absorb some of the light. If the lens has filter technology if it is bigger than usual, or if it is shaped in a different way it can affect the LUX CCTV rating for the camera.
The camera can also have a hole or opening that light passes through before setting off the sensor. This is called the “F-stop” or aperture. The further down the F-stop, the closer the image will remain focused on the camera. If the aperture is set high up, then the objects that are far away will be focused. Not as much light is needed for low F-stops when producing a specific image. More light is needed for a greater F-stop.
Most security cameras operate at a LUX rating of 1.0 or less. Some ratings can be as low as .003 LUX rating. If cameras are rated at 0.0 LUX, it has to be an infrared camera. That means there is no available light, and that means an image cannot be taken unless it is infrared.