Luminance: cd / m² simply explained
When specifying the display brightness of a smartphone, one often finds the unit cd / m2. This describes the luminance of the device. You can find out exactly what the unit means and which values are recommended in this practical tip.
Luminance as a measure of brightness
- The unit cd / m² sets the photometric size cd (abbreviation for candela) in relation to the area of the display, specified in square meters.
- Candela is the unit of measurement for light intensity. The brightness of a smartphone is directly dependent on the light intensity. A candle, for example, has a cd value of 1. A light bulb 60. The higher the candela, the higher the brightness.
- The same applies to cd / m². However, this indication of the luminance relates to a surface and not to a point, as is the case with light intensity. The luminance cd / m² therefore shows how much light is emitted by a fictitious 1-square meter smartphone.
- In summary, one can say that the luminance indicates the surface brightness that the human eye perceives.
- Sometimes the luminance is also given in "Nit". This is used primarily in the United States, but is not part of the standardized SI values.
What luminance is ideal for my smartphone?
- Common models have between 300 and 400 cd / m². Conventional computer screens and LED video walls even only 200 to 300 cd / m².
- In general, it can be said that the luminance for smartphones cannot be high enough. If the display becomes too bright, you can easily make it darker with the brightness slider.
- Luminance is particularly important when using mobile devices in bright sunshine. The high brightness of the environment usually only makes the screen appear black. Smartphones with a high cd / m² number have a clear advantage here. A prime example is the Samsung Galaxy S8, which is easy to use with over 700 cd / m² in summer.