Title:
ZOOM LENS OF REAR FOCUSING SYSTEM
Document Type and Number:
Japanese Patent JP3109342
Kind Code:
B2
Abstract:
PURPOSE: To provide a zoom lens of a rear focusing type of a variable power ratio of 10 and an F-number of about 1.6 by providing the zoom lens with five lens groups as a whole, executing focusing with a lens group backward of a variable power system and providing the whole lens system with a small size.
CONSTITUTION: This zoom lens has, successively from an object side, five lens groups; a first group L1 having a positive refracting power, a second group L2 having a negative refracting power, a third group L3 having a positive refracting power, a fourth group L4 having a positive refracting power and a fifth group L5 having a positive refracting power. Variable power from a wide angle end to a telephoto end is executed by moving the second group L2 to an image plane side. A fluctuation in the image plane according to the variable power is corrected by moving the fourth group L4 and focusing is executed by moving the fourth group. The conditions 0.4<f4/f5<1.2 are satisfied when the focal length of the i-th group is defined as fi.
Inventors:
Nobuyuki Tochigi
Application Number:
JP25499093A
Publication Date:
November 13, 2000
Filing Date:
September 17, 1993
Export Citation:
Assignee:
Canon Inc
International Classes:
G02B15/16; G02B15/167; G02B15/173; G02B13/18; (IPC1-7): G02B15/16; G02B13/18
Domestic Patent References:
| JP3154014A | ||||
| JP413110A | ||||
| JP460509A | ||||
| JP478809A | ||||
| JP519167A | ||||
| JP527172A | ||||
| JP534598A | ||||
| JP5241072A | ||||
| JP5264902A | ||||
| JP627375A | ||||
| JP6160712A |
Attorney, Agent or Firm:
Yukio Takanashi
Previous Patent: JPH03109341
Next Patent: CASCADE CONNECTION SLAVE STATION DEVICE AND DATA TRANSMITTING METHOD AND ADDRESS RECOGNIZING METHOD ...
Next Patent: CASCADE CONNECTION SLAVE STATION DEVICE AND DATA TRANSMITTING METHOD AND ADDRESS RECOGNIZING METHOD ...