Lumens/sq. foot/steradian to Candelas/square foot Converter (lm/(ft²·sr) to cd/ft²)
lm/(ft²·sr) × 1 = cd/ft²
Calculation: 1 lm/(ft²·sr) × 1 = 1 cd/ft²
Common Lumen/sq. foot/steradian to Candela/square foot Calculations
Quick-lookup reference table showing calculated equivalents for standard increments between Lumen/sq. foot/steradian (lm/(ft²·sr)) and Candela/square foot (cd/ft²).
| Conversion & Equivalent Value | Scientific Notation |
|---|---|
| 0.001 lm/(ft²·sr) 0.001 cd/ft² | 1 × 10⁻³ |
| 0.01 lm/(ft²·sr) 0.01 cd/ft² | 1 × 10⁻² |
| 0.1 lm/(ft²·sr) 0.1 cd/ft² | 1 × 10⁻¹ |
| 0.5 lm/(ft²·sr) 0.5 cd/ft² | 5 × 10⁻¹ |
| 1 lm/(ft²·sr) 1 cd/ft² | 1 × 10⁰ |
| 2 lm/(ft²·sr) 2 cd/ft² | 2 × 10⁰ |
| 5 lm/(ft²·sr) 5 cd/ft² | 5 × 10⁰ |
| 10 lm/(ft²·sr) 10 cd/ft² | 1 × 10¹ |
| 20 lm/(ft²·sr) 20 cd/ft² | 2 × 10¹ |
| 25 lm/(ft²·sr) 25 cd/ft² | 2.5 × 10¹ |
| 50 lm/(ft²·sr) 50 cd/ft² | 5 × 10¹ |
| 100 lm/(ft²·sr) 100 cd/ft² | 1 × 10² |
| 250 lm/(ft²·sr) 250 cd/ft² | 2.5 × 10² |
| 500 lm/(ft²·sr) 500 cd/ft² | 5 × 10² |
| 1000 lm/(ft²·sr) 1000 cd/ft² | 1 × 10³ |
| Reciprocal & Equivalent Value | Scientific Notation |
|---|---|
| 1 cd/ft² 1 lm/(ft²·sr) | 1 × 10⁰ |
| 5 cd/ft² 5 lm/(ft²·sr) | 5 × 10⁰ |
| 10 cd/ft² 10 lm/(ft²·sr) | 1 × 10¹ |
| 50 cd/ft² 50 lm/(ft²·sr) | 5 × 10¹ |
| 100 cd/ft² 100 lm/(ft²·sr) | 1 × 10² |
Real-World Context & Everyday Benchmarks
Tap to load into converterTo help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for Lumen/sq. foot/steradian (lm/(ft²·sr)) and Candela/square foot (cd/ft²):
Lumen/sq. foot/steradian References:
- Commercial cinema movie theater projection screen brightness 4.6452 lm/(ft²·sr)
- Standard indoor office computer desktop monitor peak brightness 27.8709 lm/(ft²·sr)
- High-end smartphone HDR screen peak outdoor sunlight brightness 139.35 lm/(ft²·sr)
- Clear blue daytime sky zenith ambient luminance 464.52 lm/(ft²·sr)
Candela/square foot References:
- Commercial cinema movie theater projection screen brightness 4.6452 cd/ft²
- Standard indoor office computer desktop monitor peak brightness 27.8709 cd/ft²
- High-end smartphone HDR screen peak outdoor sunlight brightness 139.35 cd/ft²
- Clear blue daytime sky zenith ambient luminance 464.52 cd/ft²
How to Convert Lumen/sq. foot/steradian to Candela/square foot
Converting Lumen/sq. foot/steradian (lm/(ft²·sr)) to Candela/square foot (cd/ft²) is a core calculation in Luminance, which measures the photometric luminous intensity emitted or reflected per unit area in a given direction. Both units share an identical 1:1 scale equivalence within this physical measurement domain. They represent the exact same physical magnitude under different metrological designations or derived SI formulations (1 lm/(ft²·sr) ≡ 1 cd/ft²). Any quantity expressed in Lumen/sq. foot/steradian translates directly to Candela/square foot without mathematical scaling.
Mathematical Conversion Derivation via Coherent SI Base Unit
Under the International System of Quantities (ISQ), dimensional conversion between non-SI units is rigorously resolved by bridging through the coherent SI base unit (candela per square meter (cd/m²)) without arbitrary rounding:
1 lm/(ft²·sr) = 10.76391 candela per square meter (cd/m²)1 cd/ft² = 10.76391 candela per square meter (cd/m²)V(cd/ft²) = V(lm/(ft²·sr)) × ( 10.76391 / 10.76391 ) = V(lm/(ft²·sr)) × 1Value in Candela/square foot = Value in Lumen/sq. foot/steradian × 1Direct computational formula applied for standard conversion.Converting 75 lm/(ft²·sr) yields an exact output of 75 cd/ft² in Candela/square foot. Under higher industrial throughput, 10000 lm/(ft²·sr) translates to 10000 cd/ft².
Inverse check: 1 cd/ft² = 1 lm/(ft²·sr).Understanding Lumen/sq. foot/steradian and Candela/square foot
Lumen/sq. foot/steradian
lm/(ft²·sr)A Lumen/sq. foot/steradian (lm/(ft²·sr)) is an imperial and US customary unit for luminance.
Applications & Practical Context
In practical luminance terms, a commercial cinema movie theater projection screen brightness equals 4.6452 lm/(ft²·sr), a standard indoor office computer desktop monitor peak brightness equals 27.8709 lm/(ft²·sr), a high-end smartphone HDR screen peak outdoor sunlight brightness equals 139.35 lm/(ft²·sr).
A physical magnitude of 1 lm/(ft²·sr) corresponds to 10.76391 cd/m² in standard SI measurement.
1 lm/(ft²·sr) = 10.76391 cd/m²Candela/square foot
cd/ft²A Candela/square foot (cd/ft²) is an imperial and US customary unit for luminance.
Applications & Practical Context
In practical luminance terms, a commercial cinema movie theater projection screen brightness equals 4.6452 cd/ft², a standard indoor office computer desktop monitor peak brightness equals 27.8709 cd/ft², a high-end smartphone HDR screen peak outdoor sunlight brightness equals 139.35 cd/ft².
A physical magnitude of 1 cd/ft² corresponds to 10.76391 cd/m² in standard SI measurement.
1 cd/ft² = 10.76391 cd/m²Domain Metrology & Engineering Applications
Surface Photometric Radiance (L_v = d²Φ_v / (dA·cosθ·dΩ))
Rigorously quantified in laboratory and field settings using narrow-angle spot luminance meters, imaging colorimeters, and spectroradiometers.
Applied across OLED/LCD display brightness calibration (nits), road tunnel entrance lighting, avionics cockpit HUD readability, and highway signage legibility under international metrology standard ISO 80000-7:2019, CIE 018:2019.
Physical Orders of Magnitude & Laboratory Reference Benchmarks
| Physical Phenomenon / Engineering Reference | Reference Value | Converted to Candela/square foot |
|---|---|---|
| Commercial cinema movie theater projection screen brightness | 50 cd/m² | 50 cd/ft² |
| Standard indoor office computer desktop monitor peak brightness | 300 cd/m² | 300 cd/ft² |
| High-end smartphone HDR screen peak outdoor sunlight brightness | 1500 cd/m² | 1500 cd/ft² |
| Clear blue daytime sky zenith ambient luminance | 5000 cd/m² | 5000 cd/ft² |
Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-7:2019, CIE 018:2019 and the BIPM SI Brochure (9th Edition). Governed by Surface Photometric Radiance (L_v = d²Φ_v / (dA·cosθ·dΩ)) under ISO 80000 dimensional vector [L⁻² J].
Surface Luminance to Total Luminous Intensity Bridge (Candela • Candlepower • Hefnerkerze • Millicandela • Kilocandela)
Calculate total directional luminous intensity I_v = L_v × A from emissive displays and optical diffusers, bridging surface luminance [L⁻² J] and luminous intensity [J] via aperture area (A).
I_v = L_v × A
[cd/m²] × [m²] → [cd]
-
1. Normalize Input to SI Base Unit (cd/m²):
L_v = 1 lm/(ft²·sr) × 10.76391 = 10.76391 cd/m² -
2. Apply Engineering Parameter (A):
Selected condition: 15.6" Laptop Display (0.067 m²) at A = 0.067 m² -
3. Execute Governing Physical Law in SI Units:
I_v = L_v × A = (10.76391 cd/m²) × (0.067 m²) = 0.721182 cd -
4. Convert to Standard Engineering Units:
• cd: 0.721182 × 1 = 0.7212 cd (Candela) • cp: 0.721182 × 1.02 = 0.7356 cp (Candlepower) • HK: 0.721182 × 1.107 = 0.7983 HK (Hefnerkerze) • carcel: 0.721182 × 0.1042 = 0.07515 carcel (Carcel Unit) • mcd: 0.721182 × 1000 = 721.18 mcd (Millicandela) • kcd: 0.721182 × 0.001 = 0.0007212 kcd (Kilocandela)
| Engineering Substance / Operating Standard | Parameter Value (m²) | Reference State / Condition | Typical Industrial & Engineering Application |
|---|---|---|---|
| 6.1" Smartphone Screen (0.009 m²) | 0.009 |
0.009 m² (90 cm²) | OLED mobile display panel surface aperture |
| 15.6" Laptop Display (0.067 m²) | 0.067 |
0.067 m² (670 cm²) | Commercial notebook IPS screen aperture |
| 55" Ultra HD Television (0.834 m²) | 0.834 |
0.834 m² (8,340 cm²) | Living room 4K LED/OLED television surface |
| LED Replacement Bulb Frosted Lens (0.005 m²) | 0.005 |
0.005 m² (50 cm²) | Standard A19 household diffuser globe |
| Commercial Outdoor LED Billboard (18 m²) | 18 |
18.0 m² (194 ft²) | Highway electronic digital billboard face |
Frequently Asked Questions
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