A lens system includes, in order from an object side, a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, a third lens group with positive refractive power, and a fourth lens group with positive refractive power that moves during zooming and focusing adjustments. The first lens group includes a lens with positive refractive power and an Abbe number vd1x that satisfies a following condition (vd1x>80). The second lens group includes a lens with positive refractive power and an Abbe number vd2x and two lenses with negative refractive power and Abbe numbers vd2y and vd2z respectively, the Abbe numbers Vd2x, Vd2y and Vd2z satisfying following conditions (vd2x, vd2y, vd2z