ISO 80000-7:2019

Overview

ISO 80000-7:2019 - Quantities and units - Part 7: Light and radiation specifies names, symbols, definitions and SI units for quantities used in light and optical radiation covering the wavelength range of approximately 1 nm to 1 mm. Prepared by ISO/TC 12 in collaboration with IEC/TC 25, this second edition (2019) replaces the 2008 edition and includes simplified quantity tables, clarified definitions, and appropriate conversion factors where applicable.

Key topics and technical scope

• Scope and structure
  • Standardizes radiometric, photometric and photon-related quantities (e.g., radiant energy, radiant flux, intensity, radiance) and their spectral counterparts.
  • Provides a consolidated Table 1 of quantities, symbols, definitions and units used for optical radiation.
• Representative quantities covered
  • Speed of light in a medium and refractive index (including complex refractive index and refractivity).
  • Radiant energy, spectral radiant energy, radiant flux (power) and spectral flux.
  • Radiant intensity, spectral intensity, radiance and spectral radiance.
  • Radiant energy density and spectral densities (wavelength, frequency, wavenumber representations).
• Spectral reference systems and relationships
  • Defines spectral quantities with reference to frequency, angular frequency, wavelength (vacuum/medium) and wavenumber, and gives the relationships and conversion factors between these representations.
• Vision-specific quantities
  • Photopic, scotopic and mesopic quantities are described, including reference to standard luminous efficiency functions (V(λ), V′(λ), mesopic functions) used for human-vision weighting.
• Units and notation
  • Emphasizes SI units (steradian retained in photometry/radiometry) and use of subscripts (e, v, p, mes) to distinguish energetic, visible and photon measures.

Practical applications

ISO 80000-7:2019 is essential for:

• Calibrating and specifying optical instruments (spectrometers, radiometers, photometers, imaging sensors).
• Writing technical specifications and datasheets for LEDs, lamps, displays and lighting systems.
• Metrology laboratories standardizing measurements of radiance, irradiance, flux and spectral distributions.
• Research in optics, remote sensing, spectroscopy, vision science and photobiology where consistent definitions and unit usage are critical.
• Regulatory and standards documentation that requires consistent, SI‑based optical quantity definitions.

Who should use this standard

• Metrologists, optical and illumination engineers, instrument manufacturers, test laboratories, researchers, standards developers, and technical authors preparing specifications or calibration procedures.

Related standards and references

• ISO 80000 series (other parts such as ISO 80000-1, -2, -3 referenced in definitions)
• ISO 80000-10 for ionizing radiation
• IEC terminology (e.g., IEC 60050-845) and CIE vocabularies for photometric functions

Keywords: ISO 80000-7:2019, quantities and units, light and radiation, radiometry, photometry, spectral radiance, refractive index, SI units, optical radiation standard.