Patent ID: 6839183
Filing Date: 2005-01-04
Classification: G02B

Abstract:
1. A zoom lens comprising: a first group optical system having a negative focal length, and a second group optical system having a positive focal length, which are sequentially arranged from an object side; an aperture stop which moves integrally with the second group optical system; a wide angle end; and a telephoto end, wherein, during change of magnification from a short focal end to a long focal end, the second group optical system monotonously moves from an image side to the object side, and the first group optical system moves so as to correct displacement of an image plane position in accordance with the change of magnification, wherein the first group optical system is positioned to be the closest lens group to the object side and the second group optical system is positioned adjacent the image side of the first group optical system, wherein the first group optical system includes at least one positive lens and at least one negative lens, and the second group optical system includes at least two positive lenses and at least one negative lens, and wherein the following conditional formula is satisfied: where a minimum F number at the wide angle end is F