Patent ID: 7623300

Claim:
A zoom lens comprising, in order from the object side to the image side: a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; and a fourth lens unit having positive refractive power; wherein the third lens unit includes, in order from the object side to the image side a 3a'th lens sub-unit having negative refractive power, and a 3b'th lens sub-unit having positive refractive power; and wherein the second lens unit and the fourth lens unit move on the optical axis during zooming; and wherein the 3b'th lens sub-unit moves in a direction perpendicular to the optical axis, thereby displacing an image in the direction perpendicular to the optical axis; and wherein the 3a'th lens sub-unit includes a negative lens element G3an both of whose major surfaces are spherical surfaces, and a positive lens element, both of whose both major surfaces are spherical surfaces; and wherein the 3a'th lens sub-unit includes a positive lens element G3bp having an aspherical lens surface, and a negative lens element; and wherein, when assuming that the indices of the materials of the negative lens element G3an and the positive lens element G3bp are NG3an and NG3bp respectively, a condition of 0.25≦NG3an−NG3bp is satisfied; and wherein the first lens unit includes, in order from the object side to the image side a negative lens element G 11 , a positive lens element G 12 , a positive lens element G 13 , and a positive lens element G 14 ; and wherein when assuming that the Abbe numbers of the materials of the positive lens element G 12 , positive lens element G 13 , and positive lens element G 14 are vdG 12 , vdG 13 , and vdG 14 , the conditions 60.1<vdG12<75.1 60.1<vdG13<75.1 49.1<vdG14<60.1 are satisfied.