A light source system operable in at least first and second modes to provide at least and first and second different far field illumination patterns, the system comprising: a photoluminescent material; a light beam generator for generating at least first and second independently controllable sets of light beams for illuminating respective fixed regions of the photoluminescent material; and an optical system arranged to image light emitted from the photoluminescent material into the far field; wherein the light beam generator comprises a plurality of semiconductor light emitting devices spatially separated from the photoluminescent material and independently controllable, characterized in that each of the plurality of light emitting devices generating, in use, a respective light beam illuminating a spot at a respective fixed position on the photoluminescent material; wherein, in the first mode, the light beam generator is arranged to generate the first set of light beams illuminating a first set of spots at fixed positions on the photoluminescent material defining a first fixed region of the photoluminescent material but not illuminating a second fixed region (84,111) of the photoluminescent material, the second region (84,111) being complementary to the first region; and wherein, in the second mode, the light beam generator is arranged to generate the first set of light beams illuminating the first region of the photoluminescent material and to generate the second set of light beams illuminating a second set of spots at fixed positions on the photoluminescent material defining a third fixed region (813,814) of the photoluminescent material, the third region overlapping part of the first region and/or overlapping part but not all of the second region. a photoluminescent material; a light beam generator for generating at least first and second independently controllable sets of light beams for illuminating respective fixed regions of the photoluminescent material; and an optical system arranged to image light emitted from the photoluminescent material into the far field; wherein the light beam generator comprises a plurality of semiconductor light emitting devices spatially separated from the photoluminescent material and independently controllable, characterized in that each of the plurality of light emitting devices generating, in use, a respective light beam illuminating a spot at a respective fixed position on the photoluminescent material; wherein, in the first mode, the light beam generator is arranged to generate the first set of light beams illuminating a first set of spots at fixed positions on the photoluminescent material defining a first fixed region of the photoluminescent material but not illuminating a second fixed region (84,111) of the photoluminescent material, the second region (84,111) being complementary to the first region; and wherein, in the second mode, the light beam generator is arranged to generate the first set of light beams illuminating the first region of the photoluminescent material and to generate the second set of light beams illuminating a second set of spots at fixed positions on the photoluminescent material defining a third fixed region (813,814) of the photoluminescent material, the third region overlapping part of the first region and/or overlapping part but not all of the second region.