Convert Stilbs to Apostilbs
Convert Stilbs (sb) to Apostilbs (asb) instantly and accurately.
Conversion Formula
asb = sb × 31415.92654
About Stilbs
The stilb (sb) equals 1 cd/cm² = 10⁴ cd/m². The CGS luminance unit. A candle flame has luminance ~0.5-0.6 sb; a frosted incandescent bulb ~10 sb; a xenon short-arc lamp up to 170 000 sb. Named from the Greek στίλβω (to glitter). Found in pre-1970 photometry texts. 1 sb = 10⁴ 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
| Stilbs (sb) | Apostilbs (asb) |
|---|---|
| 1 sb | 31415.9 asb |
| 2 sb | 62831.9 asb |
| 5 sb | 157080 asb |
| 10 sb | 314159 asb |
| 25 sb | 785398 asb |
| 50 sb | 1570800 asb |
| 100 sb | 3141590 asb |