Beam steerers are used in optical communications to direct a light signal towards a selected angular direction. Conventionally, the light signal is finely steered by employing mirrors to reflect the light signal. A beam steerer, arranged to direct a light signal in a free space optical communications system includes a pair 6,7 of lenses, through which a light signal 17 is transmissible, the lenses having opposite and substantially equal optical power, and displacing means 8,9 for translating one lens with respect to the other, transverse to an optical axis of the lenses. The provision of lenses permits the angular deflection of the beam per unit distance translation of a lens to be selected, as this is dependent on the optical power of the lenses. Selection of this ratio is not possible with mirror-based beam steerers.