ISO 2720:1974 Preview
Photography -- General purpose photographic exposure meters (photoelectric type) -- Guide to product specification
This standard was last reviewed and confirmed* in 2016.
*Therefore this version remains current
Specified are calibration levels and test conditions for general-purpose photoelectric exposure meters which measure reflected or incident light, or both, in determining photographic exposure for camera use. The specifications apply to exposure meters containing a light-sensitive element, and indicating electrical instrument, a directional system and a calculator to correlate the meter indications with the camera exposure settings.