Patent ID: 8085477

Claim:
A zoom lens system comprising in order from an object side: a first lens group having a negative refracting power; a second lens group having a positive refracting power; a third lens group having a positive refracting power, and a fourth lens group, wherein: the first lens group includes one cemented lens component, and the third lens group includes one lens component, and is movable for focusing, and the fourth lens group includes one lens component having an aspheric surface, and at the time of zooming from a wide angle end to a telephoto end, the second lens group moves while following a trajectory of movement only toward the object side, and the first lens group and the third lens group move while following a trajectory of movement different from the trajectory of movement of the second lens group, and the zoom lens system satisfies the following conditional expression (1) −1.5 <fw/f 4<0.3 (1) where, f4 denotes a focal length of the fourth lens group, fw denotes a focal length of the overall zoom lens system at the wide angle end when focused to a predetermined object point, and the predetermined object point is the farthest object point which can be focused, and the zoom lens system satisfies the following conditional expression (2) 1.0<β4w<2.0 (2) where, β4w denotes a magnification of the fourth lens group at the wide angle end when focused at a predetermined object point, and the predetermined object point is the farthest object point which can be focused.