The present invention relates to a luminaire comprising an array of LEDs emitting light of at least one color, and a control system for controlling the light output of the luminaire. The control system comprises photosensor array for detecting light output of the luminaire. An imaging unit is arranged in front of the photosensor array such that it maps an image of said array of LEDs on said photosensor array. The photosensor array is divided into subareas each detecting light output from a single one of the LEDs. The control system uses the output of the subareas for controlling the luminaire light output. Thus, it is possible to act on different LED light colors or the light output of individual LEDs without having to separate them in time by means of a time pulsing method.