An apparatus and method for increasing uniformity in light from a light source at a plurality of targets of the light include a plurality of movable aperture elements, locatable between the light source and the targets, each aperture element defining an aperture through which the light passes from the light source to an associated one of the plurality of targets associated with the aperture element along a longitudinal axis of the aperture element. A holder movably holds the plurality of aperture elements, each of the plurality of aperture elements being movable within the holder along the longitudinal axis of the aperture element to change a feature of light incident on the target associated with the aperture element.