Patent ID: 6587281
Filing Date: 2003-07-01
Classification: G02B

Abstract:
A zoom image pickup optical system comprising in order from an object side:a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; and a fourth lens unit having positive refractive power, wherein at least the second lens unit and the fourth lens unit are moved along an optical axis to change a magnification, wherein said third lens unit comprises at least two lens components, wherein said fourth lens unit comprises at least two lens components, and wherein R3r1 has a sign different from that of R4f1, R3r2 has a sign different from that of R4f2, R313 has a sign different from that of R4f3, and R3r4 has a sign different from that of R4f4 when a radius of curvature on an image side surface and a radius of curvature on an object side surface of a most image side lens component of the third lens unit are represented by R3r1 and R3r2 respectively, a radius of curvature on an image side surface and a radius of curvature on an object side surface of a lens component which is adjacent to said most image side lens component with an airspace interposed are designated by R3r3 and R3r4 respectively, radii or curvature on an object side surface and an image side surface of a most object side lens component of said fourth lens unit are denoted by R4f1 and R4f2 respectively, and radii of curvature on an object side surface and an image side surface of a lens component which is adjacent to said most object side lens component with an airspace interposed are represented by R4f3 and R4f4 respectively.