Patent ID: 6906868

Claim:
A zoom lens system comprising a negative first lens group, a positive second lens group, and a positive third lens group, in this order from an object, wherein said negative first lens group consists of a negative meniscus lens element having the convex surface facing toward said object, and said positive third lens group comprises a positive biconvex lens element; wherein upon zooming from the short focal length extremity to the long focal length extremity, at least said negative first lens group and said positive second lens group are moved; wherein a diaphragm is provided on the object side of said positive second lens group, and moves integrally therewith; and wherein said zoom lens system satisfies the following conditions: 0.25 <R 1 / D 1 <0.55 0.25 <f 2 / TL< 0.45 wherein R 1 designates the radius of curvature of the image-side surface of said negative meniscus lens element, which constitutes said negative first lens group; D 1 designates the distance between said negative first lens group and said positive second lens group at the short focal length extremity; f 2 designates the focal length of said positive second lens group; and TL designates the distance along the optical axis from the most object-side surface of said negative first lens group to the most image-side surface of said positive third lens group, at the short focal length extremity.