Patent ID: 6049431
Filing Date: 2000-04-11
Classification: G02B

Abstract:
A zoom lens comprising, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, and at least one lens unit located on the image side of said third lens unit,wherein said first lens unit comprises, in order from the object side to the image side, (i) only one negative lens and (ii) at least two positive lenses, with one of said at least two positive lenses being adjacent to said negative lens, and wherein an air separation between said negative lens and said positive lens adjacent thereto is the widest air separation in said first lens unit,wherein said first lens unit and said third lens unit remain stationary during performing of zooming, andwherein said zoom lens satisfies the following condition:0.18<Da/DL1<0.5where DL1 is the length of said first lens unit along an optical axis, and Da is the air separation between said negative lens and said positive lens adjacent thereto.