Patent ID: 8045274

Claim:
A zoom lens comprising: a first lens unit with a negative refractive power; a second lens unit with a positive refractive power; and a third lens unit with a positive refractive power, which are arranged in order from the object side to the image side, wherein the first lens unit includes a negative lens and a positive lens, and when the curvature radius of the object side surface of the negative lens and the curvature radius of the image side surface of the negative lens are respectively defined as R 11 and R 12 and the curvature radius of the object side surface of the positive lens and the curvature radius of the image side surface of the positive lens are respectively defined as R 21 and R 22 , R 11 , R 12 , R 21 , and R 22 , f 1 denotes a focal length of the first lens unit and f 3 denotes a focal length of the third lens unit, the following conditional expressions are satisfied: −5.6<( R 12+ R 21)/( R 12− R 21)<−4.7 1.5<( R 11 +R 22)/( R 11− R 22)<2.3 and −0.6<f1/f3<−0.3.