Patent ID: 8482861

Claim:
A zoom lens, in order from an object side to an image side thereof, comprising: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a third lens unit having a negative refractive power; and a fourth lens unit having a positive refractive power, wherein a distance between consecutive lens units of the first through fourth lens units varies for zooming, wherein the first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens whose surface on the object side has a convex shape, and wherein, when fw is a focal length of the entire zoom lens at a wide-angle end of the zoom lens, f 1 is a focal length of the first lens unit, f 3 is a focal length of the third lens unit, υd 1 p is an Abbe number of a material of the positive lens of the first lens unit, f 3 i is a focal length in air of an i-th single lens counted from the object side included in the third lens unit, υd 3 i is an Abbe number of the material of the i-th single lens counted from the object side included in the third lens unit, and Σ is a sum with respect to the focal lengths f 3 i and the Abbe numbers υd 3 i of all single lenses included in the third lens unit, the following conditions are satisfied: 0.30 <f 1 /f 3<0.68 10.0 <υd 1 p< 23.0 2.1 <f 3×Σ(100/( f 3 i×υd 3 i ))<5.0, 3.7 <|f 3 /fw|< 6.5, where i is an integer equal to or greater than 1.