Luminance / fL → sb
Convert Foot-lamberts to Stilbs
Convert visible-light luminance in candela per projected area. Convert Foot-lamberts (fL) to Stilbs (sb). Find the formula, worked examples, unit definitions, and practical guidance below.
Reverse: Stilbs to Foot-lamberts →
How to convert foot-lamberts to stilbs
Luminance describes directional brightness weighted for human vision. It differs from illuminance on a surface and cannot be converted to lux without geometry.
Use x for the value in fL, b for the intermediate value in cd/m², and y for the result in sb.
sb = fL × 3.4262590996353905 ÷ 10000
Worked examples
10 fL ≈ 0.00342625909964 sb
Step 1: (10 × 3.42625909964) ≈ 34.2625909964 cd/m².
Step 2: 34.2625909964 ÷ 10000 ≈ 0.00342625909964 sb.20 fL ≈ 0.00685251819927 sb
Step 1: (20 × 3.42625909964) ≈ 68.5251819927 cd/m².
Step 2: 68.5251819927 ÷ 10000 ≈ 0.00685251819927 sb.
Results are rounded to 12 significant digits. Converting units does not increase the precision of the original measurement. Very large or small values outside JavaScript’s finite numeric range are rejected.
About Foot-lamberts
Foot-lamberts (fL) measures luminance under the conventions above. The base value in cd/m² is (x × 3.42625909964), where x is the numerical value in fL. Factors shown here are rounded for display; calculations use the stored factor.
About Stilbs
Stilbs (sb) measures luminance under the conventions above. The base value in cd/m² is (x × 10000), where x is the numerical value in sb. Factors shown here are rounded for display; calculations use the stored factor.
Definitions and sources
Carry the same physical assumptions into subsequent physics calculations.
Foot-lamberts to stilbs reference table
| Foot-lamberts (fL) | Stilbs (sb) |
|---|---|
| 1 | 0.000342625909964 |
| 5 | 0.00171312954982 |
| 10 | 0.00342625909964 |
| 25 | 0.00856564774909 |
| 50 | 0.0171312954982 |
| 100 | 0.0342625909964 |
| 1000 | 0.342625909964 |
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