Title:
SMALL ZOOM LENS
Document Type and Number:
Japanese Patent JP3404172
Kind Code:
B2
Abstract:
PURPOSE: To provide a compact zoom lens having a wide field angle and a practical variable power ratio.
CONSTITUTION: This zoom lens performs power variation by changing the interval between a first group 1 having a positive focal distance and a second group 11 having a negative focal distance. The first group 1 is arranged, in order from the object side, a first lens 1-fourth lens 4, the second group II is arranged, in order from the object side, a fifth lens 5 and a sixth lens and an aperture stop is formed just behind the first group when representing the focal distance of the whole system at a short focus end by fW, the focal distance of the whole system at a long focus end by fT, the focal distance of the first group by fI, the focal distance of the second group by fII, a distance from the tip of lens to an entrance pupil by EP and a distance from the rear end of lens to an exit pupil at the end of the short focus by APW, the conditions: (1) 0.60<fI/fW<0.75, (2) -1.10<fII/fI<-0.90, (3) EP/fW<0.25, (4) APW/fT>-0.16 are satisfied.
Inventors:
Kazuyasu Ohashi
Application Number:
JP6138195A
Publication Date:
May 06, 2003
Filing Date:
March 20, 1995
Export Citation:
Assignee:
株式会社リコー
International Classes:
G02B13/18; G02B15/16; (IPC1-7): G02B15/16; G02B13/18
Domestic Patent References:
| JP210307A | ||||
| JP5249375A | ||||
| JP4124607A | ||||
| JP8240771A | ||||
| JP63311224A | ||||
| JP250119A | ||||
| JP7306361A |
Attorney, Agent or Firm:
Toru Kabayama (1 person outside)