A positioning mechanism for aligning an optical device and an image sensor is disclosed. The positioning mechanism includes a base operable with a support for an image sensor, a tube operable with an optical device, and an adjuster disposed between the base and the tube. In one aspect, the adjuster is positionable relative to the base in a translational degree of freedom and two rotational degrees of freedom. In another aspect, the tube is positionable relative to the adjuster in two translational degrees of freedom, and a rotational degree of freedom.