The illuminance responsivity dependencies on spectral power distributions (SPDs) of different types of light sources are studied. In this work we used three types of calibrated photometers, one of which was home-made and two were commercial photometers. A monochromator-based facility was used to scan SPDs of light sources. The dependencies of spectral mismatch correction factors F(S t ,S s ) and the illuminance responsivities of photometers versus the SPDs of tungsten-filament incandescent, fluorescent, high-pressure sodium, and metal-halide light sources and white/colored light-emitting diodes are presented throughout this work.