Title:
SUPER WIDE-ANGLE TYPE ZOOM LENS
Document Type and Number:
Japanese Patent JPH04275515
Kind Code:
A
Abstract:
PURPOSE:To suppress the generation of a distortion aberration, etc., as much as possible by providing 1st-3rd specific lens groups and moving the 2nd and 3rd lens groups along the optical axis for zooming. CONSTITUTION:The zoom lens consists of the 1st negative lens group I, 2nd negative lens group II, and 3rd positive lens group III in order from the object side. The zoom lens is zoomed from the wide-angle end to the telephoto end by moving the 2nd lens group II and 3rd lens group III along the optical axis. Namely, the 1st lens group I is fixed to suppress a shift in the position of a main light beam incident on the 1st lens group I, the light passed through the 1st lens group I is made small in incidence angle and suppressed in incidence height, and the light in this state is made incident on the 2nd lens group II to suppress aberration variation accompanying the movement of the 2nd lens group. Further, a positive lens which has an aspherical surface on the image side is provided in the 3rd lens group III, and the 1st lens group I and the aspherical surface of this positive lens are arranged across the stop to compensate the spherical aberration and comatic aberration excellently and also remove a sagittal flare.
Inventors:
TANAKA TSUNEFUMI
Application Number:
JP3741991A
Publication Date:
October 01, 1992
Filing Date:
March 04, 1991
Export Citation:
Assignee:
CANON KK
International Classes:
G02B13/18; G02B15/16; G02B15/177; (IPC1-7): G02B13/18; G02B15/16
Attorney, Agent or Firm:
Tatsuya Nagao