Patent ID: 7948686

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, in order from the object side to the image side a negative lens element G 3 an 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 3b′th lens sub-unit includes, in order from the object side to the image side a positive lens element G 3 bp having an aspherical lens surface, and a negative lens element; wherein, when assuming that the indices of the materials of the negative lens element G 3 an and the positive lens element G 3 bp are NG 3 an and NG 3 bp respectively, a condition of 0.25≦ NG 3 an−NG 3 bp is satisfied, and wherein when assuming that the index of the material of the positive lens element having the highest index of a material which is part of the fourth lens unit is NG 4 p , a condition of 0.07< NG 4 p−NG 3 bp is satisfied.