Patent ID: 6118592
Filing Date: 2000-09-12
Classification: G02B

Abstract:
A zoom lens system comprising:a plurality of lens units arranged along an optical axis between and including an image side lens unit, which is closest to an image side of the zoom lens system, and an object side lens unit, which is closest to an object side of the zoom lens system, said plurality of lens units including at least one lens unit having a positive optical power and at least one lens unit having a negative optical power;wherein said image side lens unit has a negative optical power,wherein at least two lens units of said plurality of lens units, including said image side lens unit, are movable in a zooming operation from a shortest focal length condition to a longest focal length condition; andwherein the zoom lens system satisfies the following conditions: ##EQU15## where LBw represents a back focus length at said shortest focal length condition;fw represents a focal length of the zoom lens system at said shortest focal length condition;fN represents a focal length of a lens unit, having a negative optical power, which is closest to said object side;img represents a diameter of an image circle; andR represents an effective diameter of an optical path of a lens face closest to said image side of the zoom lens system.