Patent ID: 7773311

Claim:
A zoom lens comprising: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a rear unit including one or more lens units, wherein the first lens unit, the second lens unit, and the rear unit are arranged in order from the object side to the image side, wherein the zoom lens performs zooming by changing distances between the first, second, and rear lens units; and a first focusing unit and a second focusing unit which move independently of each other during focusing, the second focusing unit including one or more positive lenses and one or more negative lenses, wherein the following condition is satisfied: (−1) Δg ×(ν N 2−ν P 2)×(−1) ΔX2 >0 where νN 2 is an average Abbe number of one or more materials of the one or more negative lenses in the second focusing unit, νP 2 is an average Abbe number of one or more materials of the one or more positive lenses in the second focusing unit, Δg=1 and Δg=2 respectively represent the state in which a focus position for the g-line for a close distance is shifted from a focus position for the g-line for infinity in a direction from the periphery of a screen to the center thereof and the state in which the focus position for the g-line for the close distance is shifted from the focus position for the g-line for infinity in a direction from the center of the screen to the periphery thereof when focusing is performed from infinity to the close distance with respect to an off-axis object point using only the first focusing unit, and ΔX 2 =1 and ΔX 2 =2 respectively represent the state in which the second focusing unit moves from the image side to the object side and the state in which the second focusing unit moves from the object side to the image side during focusing from infinity to the close distance.