Abstract: An imaging system for producing a stereoscopic image of an object is provided. The imaging system includes a camera for receiving an image of the object, a single-axis optical system disposed between the object and the camera, and an image blocking element disposed between the object and the camera. The image blocking element is activatable to alternately produce a left image and a right image, and is adjustable in a direction perpendicular to the optical axis of the optical system such that the image blocking element is capable of being centered on the aperture (i.e., the entrance pupil, exit pupil, or aperture stop) of the optical system.