An automated luminaire, comprising: a combined light source (32, 30) configured to produce an emitted light beam, the combined light source comprising a short arc discharge lamp mounted in a fixed position within an ellipsoidal reflector such that the arc is positioned near a first focus of the ellipsoidal reflector, the combined light source (32, 30) having an optical axis and being configured to move along the optical axis; a compensation module (34, 2634) optically coupled to the combined light source, the compensation module comprising a diffuser (50, 2650); an optical device (36, 37, 38) configured to receive the emitted light beam and to produce one of a modified light beam and an unmodified light beam; and a controller configured to: determine whether the optical device is producing the modified beam or the unmodified light beam and, in response to determining that the optical device is producing the modified light beam, move the combined light source (32, 30) along the optical axis to a selected position relative to the optical device (36, 37, 38), the position selected to locate a second focus of the ellipsoidal reflector in front of or behind the optical device, and the controller being further configured to move the combined light source along the optical axis to the selected position in response to the compensation module (34, 2634) positioning the diffuser in the emitted light beam. a combined light source (32, 30) configured to produce an emitted light beam, the combined light source comprising a short arc discharge lamp mounted in a fixed position within an ellipsoidal reflector such that the arc is positioned near a first focus of the ellipsoidal reflector, the combined light source (32, 30) having an optical axis and being configured to move along the optical axis; a compensation module (34, 2634) optically coupled to the combined light source, the compensation module comprising a diffuser (50, 2650); an optical device (36, 37, 38) configured to receive the emitted light beam and to produce one of a modified light beam and an unmodified light beam; and a controller configured to: determine whether the optical device is producing the modified beam or the unmodified light beam and, in response to determining that the optical device is producing the modified light beam, move the combined light source (32, 30) along the optical axis to a selected position relative to the optical device (36, 37, 38), the position selected to locate a second focus of the ellipsoidal reflector in front of or behind the optical device, and the controller being further configured to move the combined light source along the optical axis to the selected position in response to the compensation module (34, 2634) positioning the diffuser in the emitted light beam. determine whether the optical device is producing the modified beam or the unmodified light beam and, in response to determining that the optical device is producing the modified light beam, move the combined light source (32, 30) along the optical axis to a selected position relative to the optical device (36, 37, 38), the position selected to locate a second focus of the ellipsoidal reflector in front of or behind the optical device, and the controller being further configured to move the combined light source along the optical axis to the selected position in response to the compensation module (34, 2634) positioning the diffuser in the emitted light beam.