Exposure Converter Calculator
Convert between exposure units
Category: Unit Conversion
Exposure Converter Calculator Inputs
Exposure Converter Calculator Formula
Equation
value * (fromUnit_factor / toUnit_factor)
Excel Formula
=value*(fromUnit_factor/toUnit_factor)
Variables
- Value — Enter the Value value used by the Exposure Converter.
- From Unit — Choose the From Unit option used by the Exposure Converter.
- To Unit — Choose the To Unit option used by the Exposure Converter.
How the Exposure Converter Calculator Works
Exposure in photography and lighting refers to the amount of light per unit area reaching a photographic film or digital sensor. It is typically measured as the product of illuminance (light intensity) and time. Understanding exposure conversion is crucial for photographers, lighting designers, and engineers working with light measurement systems.
The core relationship is value * (fromUnit_factor / toUnit_factor). Typical inputs include Value, From Unit, To Unit.
Enter your values in the exposure converter calculator above, review the step-by-step solution, and compare against the worked examples below so you can see how each input changes the result. This free online unit conversion tool is built for homework, design checks, and professional verification.
Exposure Converter Calculator Theory & Explanation
What is Exposure?
Exposure (H) is the total amount of light energy per unit area that reaches a surface over a given time period. It is mathematically defined as:
**H = E × t**
Where: • H = Exposure (lux·seconds or equivalent units) • E = Illuminance (lux or equivalent units) • t = Time (seconds)
This fundamental relationship shows that exposure depends on both the intensity of light and the duration of exposure.
H = E × t
Common Exposure Units
Different exposure units are used in various fields:
**1. Lux·Second (lx·s)** • SI unit for exposure • Most commonly used in photography • 1 lux·second = 1 lumen·second per square meter
**2. Foot-Candle·Second (fc·s)** • Imperial unit for exposure • Used in American lighting industry • 1 foot-candle·second = 1 lumen·second per square foot
**3. EV (Exposure Value)** • Logarithmic scale used in photography • Represents exposure in stops • Each EV step doubles or halves the exposure
**4. Candela·Second per Square Meter (cd·s/m²)** • Alternative SI unit • Used in specialized lighting applications
\beginalign*
\text1 lux · \texts &= \text1 lumen · \texts/m^2 \\
\text1 foot-candle · \texts &= \text1 lumen · \texts/ft^2 \\
\textEV &= \log_2((H)/(H_0))
\endalign*
Conversion Factors and Relationships
The conversion between different exposure units follows these relationships:
**Lux to Foot-Candles:** 1 lux = 0.0929 foot-candles 1 foot-candle = 10.764 lux
**Area Conversion:** 1 square meter = 10.764 square feet 1 square foot = 0.0929 square meters
**EV Scale:** The EV scale is logarithmic, where each step represents a doubling of exposure: EV = log₂(H/H₀) Where H₀ is a reference exposure value.
\beginalign*
\text1 lux &= 0.0929 \text foot-candles \\
\text1 foot-candle &= 10.764 \text lux \\
\text1 m^2 &= 10.764 \text ft^2 \\
\textEV &= \log_2((H)/(H_0))
\endalign*
Practical Applications
**Photography:** • Exposure values determine image brightness • Proper exposure ensures correct image reproduction • EV scale helps photographers understand exposure relationships
**Lighting Design:** • Exposure calculations for architectural lighting • Safety lighting requirements • Energy efficiency calculations
**Scientific Applications:** • Photographic dosimetry • Light measurement in laboratories • Calibration of light meters
**Industrial Applications:** • Quality control in manufacturing • UV curing processes • Photolithography in semiconductor manufacturing
\textExposure = \textIlluminance × \textTime = E × t
Exposure Value (EV) Scale
The EV scale is a logarithmic scale that simplifies exposure calculations:
**EV Scale Reference:** • EV 0 = 2.5 lux·seconds (moonlight) • EV 5 = 80 lux·seconds (indoor lighting) • EV 10 = 2,560 lux·seconds (overcast day) • EV 15 = 81,920 lux·seconds (bright sunlight)
**EV Calculation:** EV = log₂(f²/t) Where f is the f-number and t is the shutter speed.
**Exposure Compensation:** Each EV step doubles or halves the exposure, making it easy to adjust camera settings.
\beginalign*
\textEV &= \log_2((f^2)/(t)) \\
\textEV &= \log_2((H)/(H_0)) \\
\textwhere H_0 &= 2.5 \text lux·seconds
\endalign*
Conversion Examples
**Example 1: Lux·Second to Foot-Candle·Second** Convert 100 lux·seconds to foot-candle·seconds: 100 lx·s × 0.0929 = 9.29 fc·s
**Example 2: Foot-Candle·Second to Lux·Second** Convert 50 foot-candle·seconds to lux·seconds: 50 fc·s × 10.764 = 538.2 lx·s
**Example 3: EV to Lux·Second** Convert EV 8 to lux·seconds: H = H₀ × 2^EV = 2.5 × 2^8 = 2.5 × 256 = 640 lx·s
**Example 4: Lux·Second to EV** Convert 320 lux·seconds to EV: EV = log₂(320/2.5) = log₂(128) = 7
\beginalign*
\text100 lx · \texts × 0.0929 &= \text9.29 fc · \texts \\
\text50 fc · \texts × 10.764 &= \text538.2 lx · \texts \\
H &= H_0 × 2^\textEV = 2.5 × 2^8 = 640 \text lx · \texts \\
\textEV &= \log_2((320)/(2.5)) = \log_2(128) = 7
\endalign*
Exposure Converter Calculator Worked Examples
Worked Example
Inputs
- value: 1
- fromUnit: ev
- toUnit: lux_second
Result: 10
Explanation
To convert 1 ev to lux second: 1 × 10 = 10 lux second
Second Scenario
Inputs
- value: 1.2
- fromUnit: ev
- toUnit: lux_second
Result: 10
Explanation
This scenario uses different inputs (value = 1.2, fromUnit = ev, toUnit = lux_second) to show how changing one variable affects the exposure converter result. Run the calculator above with these values to get the exact updated output with step-by-step work.
Common Exposure Converter Calculator Use Cases
- Exposure Converter homework and study
- Exposure Converter design and analysis
- Quick exposure converter estimates
- Verifying spreadsheet or hand calculations
Exposure Converter Calculator FAQs
What is exposure in photography and lighting?
Exposure is the total amount of light energy per unit area that reaches a surface over a given time period. It is calculated as the product of illuminance (light intensity) and time: H = E × t. In photography, proper exposure ensures that the right amount of light reaches the film or sensor to create a well-exposed image.
What are the most common exposure units?
The most common exposure units are:
• **Lux·seconds (lx·s)** - SI unit, most widely used in photography • **Foot-candle·seconds (fc·s)** - Imperial unit, used in American lighting industry • **EV (Exposure Value)** - Logarithmic scale used in camera settings • **Candela·seconds per square meter (cd·s/m²)** - Alternative SI unit
Each unit serves different purposes in various fields of application.
How do I convert between lux·seconds and foot-candle·seconds?
To convert between these units:
• **Lux·seconds to foot-candle·seconds:** Multiply by 0.0929 • **Foot-candle·seconds to lux·seconds:** Multiply by 10.764
Example: 100 lux·seconds = 100 × 0.0929 = 9.29 foot-candle·seconds
What is the Exposure Value (EV) scale?
The EV scale is a logarithmic scale that simplifies exposure calculations in photography. Each EV step represents a doubling or halving of exposure. The formula is EV = log₂(H/H₀), where H₀ = 2.5 lux·seconds. Common EV values:
• EV 0 = 2.5 lx·s (moonlight) • EV 8 = 640 lx·s (indoor lighting) • EV 15 = 81,920 lx·s (bright sunlight)
Why are there different exposure units?
Different exposure units exist because:
• **Regional preferences** - Imperial vs. metric systems • **Industry standards** - Photography, lighting design, scientific applications • **Mathematical convenience** - Logarithmic scales for complex calculations • **Historical reasons** - Legacy systems and established practices
Each unit system has advantages for specific applications and user groups.
How does exposure affect photography?
Exposure directly affects image quality in photography:
• **Underexposure** - Image appears too dark, loss of shadow detail • **Overexposure** - Image appears too bright, loss of highlight detail • **Proper exposure** - Balanced brightness with good detail in shadows and highlights
Understanding exposure units helps photographers achieve consistent results across different lighting conditions.
What is the relationship between exposure, aperture, and shutter speed?
In photography, exposure is controlled by three factors:
• **Aperture (f-number)** - Controls light intensity • **Shutter speed** - Controls exposure time • **ISO sensitivity** - Controls sensor sensitivity
The relationship is: Exposure = (f-number)² / (shutter speed) × ISO factor. This is why the EV scale is so useful - it combines these factors into a single value.
How accurate are exposure conversion calculations?
Exposure conversion calculations are mathematically precise when using the correct conversion factors:
• **Lux to foot-candles:** 1 lux = 0.09290304 foot-candles (exact) • **Area conversions:** 1 m² = 10.7639104 ft² (exact) • **EV calculations:** Logarithmic precision to many decimal places
However, practical accuracy depends on the precision of your input values and the specific application requirements.
Can I use exposure converters for scientific applications?
Yes, exposure converters are essential for many scientific applications:
• **Photographic dosimetry** - Measuring radiation exposure • **Light measurement** - Laboratory and field studies • **Calibration** - Light meter and sensor calibration • **Research** - Photobiology and materials science
Scientific applications often require high precision and specific unit conversions for accurate measurements.
What are some practical tips for using exposure converters?
Here are some practical tips:
• **Always verify units** - Double-check input and output units • **Use appropriate precision** - Match decimal places to your needs • **Consider context** - Different applications may require different units • **Round appropriately** - Don't over-specify precision • **Check calculations** - Verify results with known reference values
These practices ensure accurate and reliable exposure conversions.