ISO/CIE 19476:2014 is applicable to illuminance and luminance meters. It defines quality indices characterizing the performance of such devices in a general lighting measurement situation, as well as measurement procedures for the individual indices and standard calibration conditions. Measurements of illuminance or luminance and their accuracy are influenced by various parameters, such as operational conditions, properties of light sources, as well as characteristics of the applied photometers. The characteristics of these photometers alone do not allow the determination of the measurement uncertainty for a specific measurement task. Nevertheless, it is generally true that instruments with "better" characteristics in most cases produce smaller uncertainties than instruments with "worse" properties.