Convert Candelas per square metre to Apostilbs
Convert Candelas per square metre (cd/m²) to Apostilbs (asb) instantly and accurately.
Conversion Formula
asb = cd/m² × 3.141592654
About Candelas per square metre
The candela per square metre (cd/m²), informally called the nit, is the SI coherent unit of luminance. A typical laptop screen is 250-500 cd/m²; an HDR TV reaches 1 000-4 000 cd/m²; a clear blue sky is ~3 000-8 000 cd/m². Luminance is the photometric quantity directly perceived as brightness. 1 cd/m² = 1 nit.
About Apostilbs
The apostilb (asb) equals 1/π cd/m² ≈ 0.3183 cd/m², defined as the luminance of a perfectly diffuse Lambertian surface with an exitance of 1 lm/m². Introduced by the CIE in 1940 and used in European photometry standards and retinal illuminance calculations. 1 asb = 1/π cd/m² ≈ 0.3183 cd/m².
Quick Reference Table
| Candelas per square metre (cd/m²) | Apostilbs (asb) |
|---|---|
| 1 cd/m² | 3.14159 asb |
| 2 cd/m² | 6.28319 asb |
| 5 cd/m² | 15.708 asb |
| 10 cd/m² | 31.4159 asb |
| 25 cd/m² | 78.5398 asb |
| 50 cd/m² | 157.08 asb |
| 100 cd/m² | 314.159 asb |