Patent ID: 8144394

Claim:
A stereoscopic imaging optical system comprising, in order from its object side, one objective lens and a plurality of zoom imaging optical systems, characterized in that: each of said zoom imaging optical systems comprises, in order from its object side, a positive first group, a negative second group, an aperture stop, a positive third group and a positive fourth group, wherein: said second group moves on an optical axis for zooming, said fourth group moves on the optical axis in association with said second group for correcting an image position fluctuation incidental on zooming, and the following conditions are satisfied: −1 <mg rw <−0.2 (1) −0.4<Δ G4 /Δ G2 <0.4 (2) where mg rw is an imaging magnification at a low zoom ratio end of a whole of the groups on an image side with respect to the aperture stop, Δ G4 is a difference in an optical axis direction between a position of the fourth group at a low zoom ratio end and a position of the fourth group at a high zoom ratio end provided that + is on the image side, and Δ G2 is a difference in an optical axis direction between a position of the second group at a low zoom ratio end and a position of the second group at a high zoom ratio end provided that + is on the image side.