Title:
ZOOM LENS
Document Type and Number:
WIPO Patent Application WO/2014/126145
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a high magnification zoom lens that, while having high quality image forming performance, can achieve both compactness and price reduction. In order to achieve the foregoing, provided is a zoom lens that has a positive first lens group (G1) to a positive fourth lens group (G4) and achieves a prescribed variable magnification ratio by, when varying magnification, causing all the lens groups to move forward and backward along a light axis direction. The zoom lens is characterized by the following: the first lens group (G1) has a negative lens (11), a positive lens (12), and a positive lens (13); the second lens group (G2) has at least two negative lenses (21, 22) and one positive lens (23); the third lens group (G3) has, in order from the object side, two lenticular positive lenses (31, 32) and a negative lens (33); and the zoom lens satisfies conditional formula (1) and conditional formula (2). [1]-42≤f123t/f4×Z≤-25 ••• (1); 8.2≤f3/f4×Z≤13.6 ••• (2). In conditional formula (1) and conditional formula (2), f123t is the combined focal length at the telephoto end of the third lens group from the first lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, and z is the zoom ratio (focal length of the telephoto end/focal length of the wide angle end).
Inventors:
ADACHI NOBUYUKI (JP)
Application Number:
PCT/JP2014/053315
Publication Date:
August 21, 2014
Filing Date:
February 13, 2014
Export Citation:
Assignee:
TAMRON KK (JP)
International Classes:
G02B15/20; G02B13/18; G03B5/00
Foreign References:
| JP2009042261A | 2009-02-26 | |||
| JP2009009104A | 2009-01-15 | |||
| JPH10133109A | 1998-05-22 | |||
| JP2010015003A | 2010-01-21 | |||
| JP2010169983A | 2010-08-05 | |||
| JP2002107629A | 2002-04-10 | |||
| JP2010217549A | 2010-09-30 | |||
| JP2012159746A | 2012-08-23 | |||
| JP2008216440A | 2008-09-18 | |||
| JP2000330016A | 2000-11-30 |
Attorney, Agent or Firm:
YOSHIMURA, KATSUHIRO (JP)
Katsuhiro Yoshimura (JP)
Katsuhiro Yoshimura (JP)
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