Units of illuminance

The unit of illuminance is the lux (lx). Illuminance measures the amount of light that falls on a surface per unit area. One lux is defined as one lumen per square meter. In practical terms, it quantifies the intensity of light as perceived by the human eye in terms of how well a surface is illuminated. For example, typical illuminance levels may range from around 100 lux for a well-lit room to over 10,000 lux for direct sunlight.

Exposure Value (EV) is a numerical representation of a photographic exposure, which considers the combination of aperture (f-stop), shutter speed, and ISO sensitivity. It provides a way to quantify exposure settings in a way that allows photographers to evaluate different exposure configurations while maintaining the same level of brightness in an image. Here's a breakdown of the components: 1. **Aperture (f-stop)**: Determines how much light enters the camera. A lower f-number (e.g., f/2.

A foot-candle (fc) is a unit of illumination that measures the intensity of light falling on a surface. It is defined as the illumination produced by a light source of one candle power at a distance of one foot. In practical terms, one foot-candle is equivalent to one lumen per square foot. The measurement is often used in lighting design, photography, and film production to evaluate how much light reaches a given area.

"Lux" can refer to several different concepts depending on the context. Here are a few: 1. **Illumination/Light Measurement**: In scientific terms, "lux" is a unit of measurement for illuminance, which quantifies the amount of light that is received on a surface area. One lux is equal to one lumen per square meter. It is commonly used in fields related to lighting design and architecture.

"Phot" could refer to a few different things depending on the context. Here are a few possible interpretations: 1. **Phot (Unit of Measurement)**: In scientific contexts, particularly in optics and photometry, "phot" is a unit used to measure luminous flux per unit area, though it is more commonly referred to in terms of lumens or lux in modern usage.