Patent ID: 7643224
Filing Date: 2010-01-05
Classification: G02B

Abstract:
1. A zoom lens comprising, in order from an object side thereof: a first lens unit having a positive refracting power; a second lens unit having a negative refracting power; and a rear group having a positive refracting power that comprises at least one lens unit, a lens unit located closest to the object side in the rear group being a third lens unit having a positive refracting power, wherein the zoom lens comprises an aperture stop disposed closer to an image side than the second lens unit and closer to the object side than a lens surface closest to the image side in the third lens unit, during zooming from a wide angle end to a telephoto end in a state in which the zoom lens is focused on an object at a farthest distance, a distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, and a distance between the second lens unit and the third lens unit is smaller at the telephoto end than at the wide angle end, the first lens unit moves during zooming from the wide angle end to the telephoto end and is located closer to the object side at the telephoto end than at the wide angle end, the second lens unit moves during zooming from the wide angle end to the telephoto end and finally moves toward the image side, during zooming from the wide angle end to the telephoto end, the aperture stop first moves toward the object side, assumes a state in which it is located closest to the object side at an intermediate point in zooming from the wide angle end to the telephoto end, then reverses its moving direction in this state, and is located closer to the object side at the telephoto end than at the wide angle end, during zooming from the wide angle end to the telephoto end, the third lens unit first moves toward the object side, assumes a state in which it is located closest to the object side at an intermediate point in zooming from the wide angle end to the telephoto end, then reverses its moving direction in this state, and is located closer to the object side at the telephoto end than at the wide angle end, when an intermediate zoom state is defined as a state in which the third lens unit is located closest to the object side, the first lens unit is located closer to the object side in the intermediate zoom state than at the wide angle end, and the aperture stop is located closer to the object side in the intermediate zoom state than at the wide angle end, and the zoom lens satisfies the following conditional expression:  where f