What is LUX?
Measuring Illumination: the Unit of Lux
If a candle is one foot away from an object, it gives one foot-candle of light illuminance onto the object.
This is about 10 “lux,” and is an informal definition of lux. The unit of lux (illuminance value) tries to
relate the actual energy per unit-area falling on a surface to what the human eye perceives
| Direct sunlight | 100,000 - 130,000 lux |
| Full daylight, indirect sunlight | 10,000 - 20,000 lux |
| Overcast day | 1,000 lux |
| Indoor office | 200 - 400 lux |
| Very dark day | 100 lux |
| Twilight | 10 lux |
| Deep twilight | 1 lux |
| Full moon | 0.1 lux |
| Quarter moon | 0.01 lux |
| Moonless clear night sky | 0.001 lux |
| Moonless overcast night sky | 0.0001 lux |