Patent ID: 7719774
Filing Date: 2010-05-18
Classification: G02B

Abstract:
1. A zoom lens system 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 lens group having a positive refracting power, which includes a third lens unit having a positive refracting power; and an aperture stop which is disposed between the second lens unit and the third lens unit, wherein at a time of zooming from a wide angle end to a telephoto end, when focused on an object at a longest distance, at the telephoto end, the first lens unit moves to be positioned more toward an object side, than at a wide angle end, at the telephoto end, the second lens unit moves to be positioned more toward an image side, than at the wide angle end, at the telephoto end, the aperture stop moves to be positioned more toward the object side, than at the wide angle end, and at the telephoto end, the third lens unit moves to be positioned more toward the object side, than at the wide angle end, and a combined system of the first lens unit and the second lens unit at the wide angle end has a negative refracting power, and at the time of zooming from the wide angle end to the telephoto end, the second lens unit is positioned more toward the object side than a position of the second lens unit at the wide angle end, and when a state in which, the second lens unit is positioned closest to the object is defined as an intermediate zoom state, at the intermediate zoom state, the first lens unit moves to be positioned more toward the object side, than at the wide angle end, at the intermediate zoom state, the aperture stop moves to be positioned more toward the object side, than at the wide angle end, at the intermediate zoom state, the third lens unit moves to be positioned more toward the object side, than at the wide angle end, and at the intermediate zoom state, an object point of the third lens unit moves to be positioned more toward the object side, than at the wide angle•end, and the zoom lens system satisfies the following conditional expression where, f f