Fotometriában

Fotometriában is a branch of optical science concerned with the measurement of light intensity. It deals with quantities that are weighted by the response of the human eye, where the response is based on spectral sensitivity. The fundamental photometric unit is the lumen, which measures luminous flux. Luminous intensity, measured in candela, describes the light emitted by a source in a particular direction. Illuminance, measured in lux, quantifies the amount of light falling on a surface. Radiometry, on the other hand, measures light in terms of physical power without considering the human eye's perception.

Photometric measurements are crucial in various fields. In photography, understanding illuminance helps in setting exposure. In lighting design, it aids in determining the appropriate amount of light for different environments, ensuring visual comfort and functionality. Astronomy also employs photometry to measure the brightness of celestial objects, providing insights into their properties and distances. Specialized instruments called photometers are used for these measurements. These devices typically consist of a detector sensitive to visible light, circuitry to process the signal, and a display to show the measured value. The accuracy of photometric measurements depends on the calibration of the photometer and the environmental conditions.