Patent ID: 7965451

Claim:
A zoom lens comprising, in order from an object side: a first lens unit with negative power; a second lens unit with positive power; a third lens unit with positive power; and a fourth lens unit, wherein when a magnification of the zoom lens is changed in a range from a wide-angle position to a telephoto position, spacing between the first lens unit and the second lens unit is narrowed and spacing between the second lens unit and the third lens unit is widened; an aperture stop moved integrally with the second lens unit is interposed between a most image-side lens element of the first lens unit and a most image-side lens element of the second lens unit; and the first lens unit consists of a first lens element with negative power placed on the object side and a second lens element with positive power placed on an image side and satisfies the following conditions: 0.15<φ 1MF /φ 1MR <1.0 −3.0<φ 1PF /φ 1PR <−1.0 where φ 1MF is a power of an object-side surface of the first lens element with negative power of the first lens unit, φ 1MR is a power of an image-side surface of the first lens element with negative power of the first lens unit, φ 1PF is a power of an object-side surface of the second lens element with positive power of the first lens unit, and φ 1PR is a power of an image-side surface of the second lens element with positive power of the first lens unit.