Patent ID: 8199412

Claim:
A zoom lens comprising a plurality of lens units and performs zooming from the wide angle end to the telephoto end by changing distances between the plurality of lens units, wherein the zoom lens comprises, in order from the object side to the image side, an object side lens group having a negative refracting power at the wide angle end and including at least one negative lens unit having a negative refracting power, and an image side lens group having a positive refracting power at the wide angle end and including at least one positive lens unit having a positive refracting power, wherein the distance between the object side lens group and the image side lens group is smaller at the telephoto end than at the wide angle end, the at least one positive lens unit having a positive refracting power in the image side lens group comprises a cemented doublet lens component, the cemented doublet lens component comprises, in order from the object side to the image side, an object side lens, which is a negative lens having a concave surface facing the image side, and an image side lens, which is a positive meniscus lens having a concave surface facing the image side, the cemented doublet lens component is located closest to the image side in the positive lens unit, and the zoom lens satisfies the following conditions: 0.20 <R f /f IP1 <1.40 (1), and 0.5 <SF cem <20.0 (3), where SF cem =(R f +R r )/(R f −R r ), R f is the radius of curvature of the object side surface of the object side lens in the cemented doublet lens component, R r is the radius of curvature of the image side surface of the image side lens in the cemented doublet lens component, and f IP1 is the focal length of the positive lens unit including the cemented doublet lens component.