Patent ID: 7643221

Claim:
A zoom lens comprising: a first lens unit that does not move for zooming and that has a positive refractive power; a second lens unit that is configured to move to an image side during zooming from a wide angle end to a telephoto end, and that has a negative refractive power; a third lens unit that is configured to reduce image plane variation due to zooming; and a fourth lens unit that does not move for zooming, wherein the first to fourth lens units are arranged in that order from an object side to the image side of the zoom lens, wherein the fourth lens unit comprises a fourth-F unit and a fourth-B unit that are arranged in that order from the object side and facing each other across the longest air gap in the fourth lens unit, wherein the fourth-B unit comprises two negative lenses and at least three positive lenses, and comprises a fourth-B 1 unit and a fourth-B 2 unit, wherein the center of a thickness of at least one lens included in the fourth-B 1 unit is closer to the object side than the center of a total length of the fourth-B unit, and the center of a thickness of at least one lens included in the fourth-B 2 unit is closer to the image side than the center of the total length of the fourth-B unit, wherein each of the fourth-B 1 unit and the fourth-B 2 unit includes at least one negative lens and at least one positive lens, and wherein the following conditions are satisfied: 0.50 <v 1 p/v 1 n< 1.10 2.30 <v 2 p/v 2 n where v1p represents an average of Abbe number of material of the at least one positive lens in the fourth-B 1 unit, v2p represents an average of Abbe number of material of the at least one positive lens in the fourth-B 2 unit, v1n represents an average of Abbe number of material of the at least one negative lens in the fourth-B 1 unit, and v2n represents an average of Abbe number of material of the at least one negative lens in the fourth-B 2 unit.