Choosing the photometry distance when measuring light intensity
Abstract
Choosing the photometry distance when measuring light intensity
Incoming article date: 26.03.2025When measuring the intensity of light, the size of the light source should be small compared to the photometric distance. In this case, the law of squares of distance is fulfilled, which can be applied in practice and obtain high measurement accuracy if the photometry distance exceeds the largest size of the light source by at least 10 times. For light sources with finite dimensions at small distances to the illuminated surface, this law must be amended. This paper presents the results of calculations of errors when using the law of squares of distance for light sources of finite sizes of various shapes and various light distributions.
Keywords: the law of squares of distance, luminous intensity, measurement error, photometry distance.