What does lux measure?

Lux is a unit of measurement that quantifies the amount of visible light that illuminates a surface. It specifically indicates the level of illumination per unit area, making it relevant in contexts where understanding light intensity is essential, such as in photography, lighting design, and various applications within video surveillance systems.

When we say an area is illuminated in lux, we're assessing how well-lit that area is for human vision, as lux takes into account the human eye’s response to different wavelengths of light, effectively measuring perceived brightness. This is particularly significant for cameras and video systems, where proper lighting is crucial for image quality.

The other concepts, such as sound intensity, light speed, and air pressure, do not relate to lux. Sound intensity is measured in decibels, the speed of light in meters per second, and air pressure in pascals or atmospheres, making them distinct from the measurement of light illumination that lux represents.