Patent ID: 6195210
Filing Date: 2001-02-27
Classification: G02B

Abstract:
An image pickup lens system comprising in order from the object side: a first lens unit having a positive refractive power; and a second lens unit having a negative refractive power, wherein said lens system is configured to change a magnification by varying an airspace reserved between said first lens unit and said second lens unit, wherein said first lens unit comprises, in order from the object side, a plastic lens element having a weak refractive power, a glass lens element having a negative refractive power and a glass lens element having a positive refractive power, and wherein said second lens unit comprises, in order from the object side, a plastic lens element having a weak refractive power and a plastic lens element having a negative refractive power and wherein the distances between each of the lens elements in the first lens unit and each of the lens elements in the second lens unit are constant during the change in magnification.