an optical device may include at least one optical element and a coupling section adapted to control relative movement between the at least one optical element and the coupling section . the coupling section may include an engaging element and a detent mechanism adapted to adjustably lock the at least one optical element in a plurality of rotational positions . the rotational positions may include rotational positions around a first axis that is substantially perpendicular to a second axis of the at least one optical element , the second axis being a substantially longitudinal axis of the at least one optical element .