Patent ID: 8184377

Claim:
A zoom lens, comprising, in order from an object side to an image plane side: a first lens unit having positive refractive power; a second lens unit having negative refractive power; an aperture stop; 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: during zooming from a wide angle end to a telephoto end, the first lens unit moves along a locus convex toward the image plane side, the second lens unit moves toward the image plane side, and the aperture stop moves; at the telephoto end compared with the wide angle end, an interval between the first lens unit and the second lens unit increases, an interval between the second lens unit and the third lens unit decreases, and an interval between the aperture stop and the third lens unit decreases; and the following conditional expressions are satisfied: 0.10<| f 4/ ft|< 0.45; and 0.03< m 1mid/| m 1|<0.70, where f4 denotes a focal length of the fourth lens unit, ft denotes a focal length of an entire system at the telephoto end, m1 denotes a movement amount of the first lens unit in an optical axis direction during zooming from the wide angle end to the telephoto end, and m1mid denotes a movement amount of the first lens unit in the optical axis direction from the wide angle end to a zoom position at which the first lens unit is positioned closest to the image plane side.