Convert meter-candle [m*c] to candela steradian/sq. meter Online | Free lllumination Converter

A Traditional Unit of Illuminance

The meter-candle (m·c) is a historical unit of illuminance that measures the luminous flux falling on a surface area of one square meter from a uniform point source with an intensity of one candlepower (now replaced by the candela) placed one meter away. It was used primarily before the international adoption of the lux as the standard unit for illuminance.

One meter-candle is roughly equivalent to one lux, since lux is defined as lumens per square meter. However, the meter-candle historically provided a more intuitive measure of illuminance based on the distance from a known light source, which was practical for early lighting calculations and designs.

While the meter-candle is largely obsolete today, replaced by the lux in most scientific and engineering applications, it remains a useful reference when interpreting older lighting standards, manuals, and specifications.

Understanding the meter-candle helps in grasping the evolution of lighting measurement units and appreciating the advances in photometric science that have led to more precise and standardized units.

Understanding Radiance

Candela steradian per square meter (cd·sr/m²) is a unit of radiance, which measures the amount of light power emitted, reflected, or transmitted from a surface in a specific direction per unit area. It combines the candela (cd), which quantifies luminous intensity, with the steradian (sr), the unit of solid angle, and divides by the surface area in square meters.

Radiance describes how bright a surface appears when viewed from a particular direction and is critical in fields such as optics, imaging, computer graphics, and remote sensing. Unlike illuminance (which measures light falling on a surface), radiance tells us about the directional brightness coming off or through a surface.

This unit helps in characterizing light sources and reflective surfaces, allowing scientists and engineers to model how light behaves in complex environments. It is essential for designing lighting systems, calibrating cameras, and simulating realistic visual scenes.

Understanding candela steradian per square meter allows precise control over brightness and directional light properties, supporting advancements in display technology, vision science, and photometric measurements.