Patent ID: 6212018
Filing Date: 2001-04-03
Classification: G02B

Abstract:
A zoom lens system comprising a positive first lens group and a negative second lens group in this order from the object, and in which zooming is performed by varying the distance between said positive first lens group and said negative second lens group;wherein a diaphragm is positioned between lens elements which constitute said first lens group,wherein focusing is performed by moving said negative second lens group along the optical axis, andwherein said zoom lens has a half angle-of-view of more than 30.degree. at a short focal length extremity, andwherein said zoom lens system satisfies the following condition:0.7<.SIGMA.d.sub.s /.SIGMA.d.sub.1G <10.6<H.sub.1 /H.sub.s <0.9wherein:.SIGMA.d.sub.1G represents the distance from the most object-side surface to the most image-side surface of said first lens group;.SIGMA.d.sub.s represents the distance from the most object-side surface to the diaphragm of the first lens group;H.sub.1 represents the height of a paraxial ray which strikes the most object-side surface of said first lens group at the short focal length extremity; andH.sub.s represents the height of the paraxial ray at the position of said diaphragm when said first lens group is at the short focal length extremity.