Title:
VARIABLE POWER METHOD FOR ZOOM LENS
Document Type and Number:
Japanese Patent JP3018799
Kind Code:
B2
Abstract:
PURPOSE: To provide the variable power method for a zoom lens, by which a lens barrel structure of high accuracy and a prescribed variable power ratio can be obtained easily by utilizing two variable power systems of each different type.
CONSTITUTION: The zoom lens is provided with three lens groups of a first group L1 of negative refracting power, a second group L2 of positive refracting power, and a third group L3 of positive or negative refracting power in order from an object side, and by moving integrally two lens groups of them, first variable power from a wide angle end to a zoom position in the middle is executed, and thereafter, by separating two lens groups, and moving at least one lens group of them, second variable power from the zoom position in the middle to a telephoto end is executed.
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Inventors:
Koji Hoshi
Application Number:
JP33359392A
Publication Date:
March 13, 2000
Filing Date:
November 18, 1992
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B15/16; G02B15/20; (IPC1-7): G02B15/16; G02B15/20
Domestic Patent References:
| JP3197914A | ||||
| JP612118A | ||||
| JP60242416A |
Attorney, Agent or Firm:
Yukio Takanashi