An optics tube for an endoscope including a magnet arrangement which extends parallel to a longitudinal axis of the optics tube. A rod lens including a rod-shaped lens unit made of a rod-shaped lens element or a plurality of lens elements cemented to one another, wherein, on one side on the circumferential face thereof, the lens unit includes a magnet arrangement. The invention also relates to a combination of an optics tube and a rod lens, and to an endoscope.