Convert Nanocandelas per square metre to Apostilbs
Convert Nanocandelas per square metre (ncd/m²) to Apostilbs (asb) instantly and accurately.
Conversion Formula
asb = ncd/m² × 3.141592654e-9
About Nanocandelas per square metre
The nanocandela per square metre (ncd/m²) equals 10⁻⁹ cd/m². Represents luminance at the threshold of cooled photomultiplier tubes and avalanche photodiode detectors. The darkest OLED black levels (~10⁻⁴ cd/m²) are still five orders of magnitude brighter; this unit is used in single-photon counting photometry. 1 ncd/m² = 10⁻⁹ cd/m².
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
| Nanocandelas per square metre (ncd/m²) | Apostilbs (asb) |
|---|---|
| 1 ncd/m² | 3.142 × 10-9 asb |
| 2 ncd/m² | 6.283 × 10-9 asb |
| 5 ncd/m² | 1.571 × 10-8 asb |
| 10 ncd/m² | 3.142 × 10-8 asb |
| 25 ncd/m² | 7.854 × 10-8 asb |
| 50 ncd/m² | 1.571 × 10-7 asb |
| 100 ncd/m² | 3.142 × 10-7 asb |