A zoom lens system has a combined focal length fw at the wide angle end and includes, in order from an object side, a first lens group with positive refractive power and combined focal length f1; a second lens group with negative refractive power; a third lens group with positive refractive power; a fourth lens group with positive refractive power; and a fifth lens group with positive refractive power and including, in order from the object side, a negative biconcave lens with focal length f51 and a positive biconvex lens with focal length f52, the negative biconcave lens and the positive biconvex lens disposed with an air space shorter than a center thickness of the negative biconcave lens in between and both surfaces of the positive biconvex lens being aspherical. The system satisfies the following conditions: 13.5