Patent ID: 8351130

Claim:
A zoom lens comprising of, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a rear group including one or more lens units, wherein the first lens unit consists of a negative lens and a positive lens, the lens units move at a time of zooming, the position of the first lens unit at the telephoto end is displaced toward the object side from its position at the wide angle end, the position of the third lens unit at the telephoto end is displaced toward the object side from its position at the wide angle end, and the zoom lens satisfies the following conditional expressions: 10.5< f 1/ fw< 30.0, and 0.010<| f 2/ ft|< 0.181, where f 1 is the focal length of the first lens unit, f 2 is the focal length of the second lens unit, fw is the focal length of the whole system at the wide angle end, and ft is the focal length of the whole system at the telephoto end.