As visual perception varies logarithmically, it is helpful to have an appreciation of both illuminance and luminance by orders of magnitude.
To help compare different orders of magnitude, the following list describes various source in lux, which is a lumen per square metre.
| Factor (lux) | Multiple | Value | Item |
|---|---|---|---|
| 0 | 0 lux | 0 lux | Absolute darkness |
| 10−4 | 100 microlux | 100 microlux | Starlight overcast moonless night sky |
| 140 microlux | Venus at brightest | ||
| 200 microlux | Starlight clear moonless night sky excluding airglow | ||
| 10−3 | 1 millilux | 2 millilux | Starlight clear moonless night sky including airglow |
| 10−2 | 1 centilux | 1 centilux | Quarter Moon |
| 10−1 | 1 decilux | 2.5 decilux | Full Moon on a clear night[1] [2] [3] |
| 100 | 1 lux | < 1 lux | Extreme of darkest storm clouds, sunset or sunrise |
| 101 | 1 decalux | 40 lux | Fully overcast, sunset or sunrise |
| 102 | 1 hectolux | < 200 lux | Extreme of darkest storm clouds, midday |
| 400 lux | Sunrise or sunset on a clear day (ambient illumination) | ||
| 104 | 10 kilolux | 10–25 kilolux | Typical overcast day, midday |
| 20 kilolux | Shade illuminated by entire clear blue sky, midday | ||
| 105 | 100 kilolux | 110 kilolux | Bright sunlight |
| 120 kilolux | Brightest sunlight |
This section lists examples of luminances, measured in candelas per square metre and grouped by order of magnitude.
| Factor (cd/m2) | Multiple | Value | Item | |
|---|---|---|---|---|
| 10−6 | μcd/m2 | Absolute threshold of vision | ||
| 10−5 | ||||
| 10−4 | ||||
| 10−3 | mcd/m2 | Darkest sky | ||
| Night sky | ||||
| Typical photographic scene lit by full moon | ||||
| 10−2 | Approximate scotopic/mesopic threshold | |||
| 10−1 | ||||
| 100 | cd/m2 | Floodlit buildings, monuments, and fountains | ||
| 101 | Approximate mesopic/photopic threshold | |||
| Typical photographic scene at sunrise or sunset | ||||
| Green electroluminescent source | ||||
| 102 | Standard SMPTE cinema screen luminance | |||
| Monitor white in the sRGB reference viewing environment | ||||
| Peak luminance of a typical LCD monitor | ||||
| 103 | kcd/m2 | Typical photographic scene on overcast day | ||
| Average cloudy sky | ||||
| Moon surface | ||||
| 104 | Typical photographic scene in full sunlight | |||
| Average clear sky | ||||
| White illuminated cloud | ||||
| Fluorescent lamp | ||||
| 105 | Low pressure sodium-vapor lamp | |||
| Frosted incandescent light bulb | ||||
| 106 | Mcd/m2 | Solar disk at horizon | ||
| 107 | Filament of a clear incandescent lamp | |||
| 108 | Possible retinal damage | |||
| 109 | Gcd/m2 | Solar disk at noon |