An apparatus comprises a first light sensor configured with a first field of view; and a second light sensor configured with a second, narrower field of view contained within the first field of view. The first and second light sensors may be arranged to detect light reflected from an illuminated surface, wherein the first and second field of view encompass light from an electric lighting device reflected from said surface and additional light reflected from said surface, e.g. natural light; but the second light sensor is concentrated on a region on said surface so as to exclude glare from objects outside said region, whereas the first field of view extends beyond said region. An illumination level of the environment in which the apparatus is installed may be adjusted to compensate for a change in the additional light based on information distinguishing between the two sensors.