What does foot-lambert measure?

Foot-lambert is an imperial luminance unit quantifying luminous intensity emitted or reflected from a surface per unit projected area in a specific direction.

Why is 555 nm used in this conversion?

555 nm corresponds to the peak of human photopic vision sensitivity, making it a standard wavelength for relating radiometric and photometric quantities.

Can I use this conversion for any wavelength?

No, this conversion specifically assumes measurement at 555 nm; using other wavelengths may reduce accuracy.

Convert Foot-lambert [fL] to Watt/sq. cm/steradian (at 555 nm) Easily

Quickly convert luminance values from foot-lambert [fL] to watt per square centimeter per steradian at 555 nm with our easy-to-use online converter tool.

Foot-lambert [fL]

Watt/sq. cm/steradian (at 555 nm)

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Foot-lambert [fL] to Watt/sq. cm/steradian (at 555 nm) Conversion Table

Foot-lambert [fL]	Watt/sq. cm/steradian (at 555 nm)

Custom Unit Conversion Table Generator – Instant Printable Conversion Tables

Start Value

Enter the starting number (positive decimal or integer ≥ 0). Example: 0.1, 1, 5.

End Value

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Foot-lambert [fL] to Watt/sq. cm/steradian (at 555 nm) Conversion Table
Foot-lambert [fL]	Watt/sq. cm/steradian (at 555 nm)

Explore More Luminance Units Converter

What Is This Tool?

This tool converts luminance measurements from the imperial unit foot-lambert [fL] to the radiometric spectral radiance unit watt/sq. cm/steradian at the wavelength of 555 nm. It helps translate photometric luminance into spectral radiometric units aligned with peak human visual sensitivity.

How to Use This Tool?

Enter the luminance value in foot-lamberts [fL].
Select the output unit watt/sq. cm/steradian (at 555 nm).
Click convert to obtain the spectral radiance measurement.
Review and use the converted value for calibration or comparison.

Key Features

Converts foot-lambert values to watt per square centimeter per steradian at 555 nm.
Supports luminance measurements used in cinema, home theater, and optical metrology.
Browser-based and easy to use without requiring additional software.
Provides precise conversion relevant for vision science and photometric testing.

Examples

10 foot-lamberts [fL] equals approximately 5.01648477e-6 watt/sq. cm/steradian (at 555 nm).
0.5 foot-lambert [fL] equals about 2.50824239e-7 watt/sq. cm/steradian (at 555 nm).

Common Use Cases

Calibrating screen brightness for cinemas and home theaters in foot-lamberts and converting to radiometric units.
Measuring reflected luminance in projection system design and testing.
Performing spectral radiance characterization of small-area light sources at 555 nm for vision research.
Comparing LED or lamp output using photometric and radiometric standards.

Tips & Best Practices

Ensure input values are accurately measured in foot-lamberts for reliable conversion.
Use the conversion at the 555 nm wavelength for alignment with human visual sensitivity.
Handle very small conversion factors carefully to avoid rounding errors.
Verify calibration conditions match the assumptions of this conversion.

Limitations

Conversion applies only at the 555 nm wavelength; different wavelengths reduce accuracy.
Foot-lambert is primarily used in imperial unit contexts and may not suit all international standards.
Small magnitude of the conversion factor may require careful numerical precision handling.

Frequently Asked Questions

What does foot-lambert measure?: Foot-lambert is an imperial luminance unit quantifying luminous intensity emitted or reflected from a surface per unit projected area in a specific direction.
Why is 555 nm used in this conversion?: 555 nm corresponds to the peak of human photopic vision sensitivity, making it a standard wavelength for relating radiometric and photometric quantities.
Can I use this conversion for any wavelength?: No, this conversion specifically assumes measurement at 555 nm; using other wavelengths may reduce accuracy.

Key Terminology

Foot-lambert [fL]: An imperial unit of luminance measuring luminous intensity per unit projected area emitted or reflected from a surface.
Watt/sq. cm/steradian (at 555 nm): A radiometric spectral radiance unit expressing radiant power per unit area and solid angle at 555 nm wavelength.
Luminance: The measure of luminous intensity emitted or reflected from a surface per unit area in a given direction.

Quick Knowledge Check

What unit is foot-lambert primarily used to measure?

Radiant power

Luminance

Illuminance

At what wavelength does the conversion to watt/sq. cm/steradian apply?

555 nm

450 nm

700 nm

Which sector commonly uses foot-lambert for brightness specification?

Home theater calibration

Agriculture

Automotive engine testing

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