Title:
【発明の名称】ズームレンズ
Document Type and Number:
Japanese Patent JP3376171
Kind Code:
B2
Abstract:
A zoom lens device including in order of lens units from the lens unit closest to an object side of the zoom lens device to an image side of the zoom lens device, a first lens unit having a positive refractive power, a second lens unit for changing magnification and having a negative refractive power, a third lens unit for correcting changes in an image plane which occur as the magnification changes, and a fourth lens unit for forming an image. The first lens unit includes (i) a front lens subunit which is stationary during focusing and which has a positive refractive power and (ii) a rear lens subunit which is movable in order to bring an object into focus. The front lens subunit includes a negative lens and a positive lens. The rear lens subunit includes a negative lens and at least two positive lenses.
Inventors:
Fumiaki Usui
Application Number:
JP15614195A
Publication Date:
February 10, 2003
Filing Date:
June 22, 1995
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B15/167; G02B15/16; G02B15/17; G02B15/173; (IPC1-7): G02B15/16
Domestic Patent References:
| JP61270718A | ||||
| JP6242378A | ||||
| JP5284754A | ||||
| JP5557815A |
Attorney, Agent or Firm:
Keizo Nishiyama (1 person outside)