Patent ID: 8107171

Claim:
A zoom lens system, comprising, in an order from an object side to an image side: a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; a fourth lens unit having negative refractive power; and a fifth lens unit having positive refractive power, wherein: the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit move during zooming so that an interval between the first lens unit and the second lens unit is larger at a telephoto end than that at a wide angle end, an interval between the second lens unit and the third lens unit is smaller at the telephoto end than that at the wide angle end, an interval between the third lens unit and the fourth lens unit varies, and an interval between the fourth lens unit and the fifth lens unit is larger at the telephoto end than that at the wide angle end; and the following conditions are satisfied: 0.5< |f 2|/ fw< 2.0; −6.0< M 4/ fw<− 2.9; and 0.01<( D 34 t−D 34 w )/ fw< 1.50, where f 2 denotes a focal length of the second lens unit, fw denotes a focal length of an entire system at the wide angle end, M 4 denotes a movement amount of the fourth lens unit in zooming from the wide angle end to the telephoto end, D 34 w denotes an interval between the third lens unit and the fourth lens unit at the wide angle end, and D 34 t denotes an interval between the third lens unit and the fourth lens unit at the telephoto end.