Title:
A zoom lens, an imaging device, and a video camera for surveillance
Document Type and Number:
Japanese Patent JP6270104
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a zoom lens that has a variable power ratio of more than 25 times, the zoom lens including an extender with a magnification of about twice, having a fewer pieces of components, being small in size and lightweight and being favorably corrected in the color aberration to a near infrared region, and having resolving power responding to an imaging element having 2-million pixels or more.SOLUTION: The zoom lens has a four-group configuration with a sequence of positive, negative, negative and positive powers, in which the second lens group G2 and the third lens group G3 are moved upon varying magnifications, and an extender lens group EX is detachably attached to an image side of the fourth lens group G4. At least either of the second lens group G2 and the third lens group G3 includes a negative lens; and the negative lens satisfies [1]:1.50
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Inventors:
Kazuyasu Ohashi
Application Number:
JP2013176342A
Publication Date:
January 31, 2018
Filing Date:
August 28, 2013
Export Citation:
Assignee:
株式会社リコー
International Classes:
G02B15/24; G02B13/18; G02B15/12; H04N5/225
Domestic Patent References:
| JP6289295A | ||||
| JP10054937A | ||||
| JP8234107A | ||||
| JP2003262793A | ||||
| JP2008197534A | ||||
| JP2008209866A | ||||
| JP4095910A |
Attorney, Agent or Firm:
Shuji Sanada