JPS57133424A - Attachment lens - Google Patents

Attachment lens

Info

Publication number
JPS57133424A
JPS57133424A JP1935981A JP1935981A JPS57133424A JP S57133424 A JPS57133424 A JP S57133424A JP 1935981 A JP1935981 A JP 1935981A JP 1935981 A JP1935981 A JP 1935981A JP S57133424 A JPS57133424 A JP S57133424A
Authority
JP
Japan
Prior art keywords
lens
concave
meniscus
focal length
convex
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP1935981A
Other languages
Japanese (ja)
Inventor
Hideji Sato
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tokoh Kogyo
Original Assignee
Tokoh Kogyo
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tokoh Kogyo filed Critical Tokoh Kogyo
Priority to JP1935981A priority Critical patent/JPS57133424A/en
Publication of JPS57133424A publication Critical patent/JPS57133424A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/02—Optical objectives with means for varying the magnification by changing, adding, or subtracting a part of the objective, e.g. convertible objective
    • G02B15/10—Optical objectives with means for varying the magnification by changing, adding, or subtracting a part of the objective, e.g. convertible objective by adding a part, e.g. close-up attachment
    • G02B15/12—Optical objectives with means for varying the magnification by changing, adding, or subtracting a part of the objective, e.g. convertible objective by adding a part, e.g. close-up attachment by adding telescopic attachments

Abstract

PURPOSE:To obtain a small-size attachment lens which extends the focal length about 1.5 times and reduce the brightness to the half approximately, by satisfying prescribed conditions in the lens system consisting of convex, concave, and concave meniscus lenses. CONSTITUTION:In the lens system consisting of a meniscus convex lens having a strong convex face in the image side, a meniscus concave lens having a strong concave face in the object side, and a meniscus concave lens having a strong concave face in the object side, conditions of expressions (1)-(5) are satisfied. In these expressions, fA is the resultant focal length of the lens system, and r1- r5 are radiuses of curvature of the first- the fifth faces, respectively, and n1 and n2 are refractive indexes of the first and the second lenses, respectively. Thus, a small-size attachment lens is obtained which extends the focal length about 1.5 times and reduces the brightness to the half approximately.
JP1935981A 1981-02-10 1981-02-10 Attachment lens Pending JPS57133424A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1935981A JPS57133424A (en) 1981-02-10 1981-02-10 Attachment lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1935981A JPS57133424A (en) 1981-02-10 1981-02-10 Attachment lens

Publications (1)

Publication Number Publication Date
JPS57133424A true JPS57133424A (en) 1982-08-18

Family

ID=11997168

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1935981A Pending JPS57133424A (en) 1981-02-10 1981-02-10 Attachment lens

Country Status (1)

Country Link
JP (1) JPS57133424A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4768868A (en) * 1984-02-28 1988-09-06 Nippon Kogaku K. K. Rear conversion lens

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4768868A (en) * 1984-02-28 1988-09-06 Nippon Kogaku K. K. Rear conversion lens

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