To indicate a lighting means for a machine vision application where the resulting irradiance (P′) in an illuminated area (5) at a working distance (d) can be precisely adjusted, an optical covering (2) of the lighting means (1) is provided, which is configured such that a transmitted part (t2) of the incident light (L) passes through (1) the optical covering (2), and a reflected component (r2) of the incident light (L) is reflected in the optical covering (2), wherein a light sensor (3) is provided that detects the intensity (Ir2) of the reflected component (r2) in the optical covering (2). Furthermore, a method is indicated, according to which the intensity (Ir2) of the reflected component (r2) is detected and the radiant power (P) of the light source (1) is regulated on the basis of the intensity (Ir2) in order to adjust the irradiance (P′) of the transmitted component (t2).