JPS6452112A - Compact zoom lens with large aperture ratio - Google Patents

Compact zoom lens with large aperture ratio

Info

Publication number
JPS6452112A
JPS6452112A JP20850887A JP20850887A JPS6452112A JP S6452112 A JPS6452112 A JP S6452112A JP 20850887 A JP20850887 A JP 20850887A JP 20850887 A JP20850887 A JP 20850887A JP S6452112 A JPS6452112 A JP S6452112A
Authority
JP
Japan
Prior art keywords
group
negative
positive
ratio
refractive indexes
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
JP20850887A
Other languages
Japanese (ja)
Inventor
Kazuyoshi Hata
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.)
Minolta Co Ltd
Original Assignee
Minolta Co Ltd
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 Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP20850887A priority Critical patent/JPS6452112A/en
Priority to US07/230,173 priority patent/US5009491A/en
Publication of JPS6452112A publication Critical patent/JPS6452112A/en
Pending legal-status Critical Current

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  • Lenses (AREA)

Abstract

PURPOSE:To shorten the overall length of the zoom lens consisting of a 1st group with a negative refractive index and 2nd and 3rd groups with positive refractive indexes by setting the refractive indexes, focal lengths, etc., of the 1st and 2nd groups within specific ranges. CONSTITUTION:The room lens consisting of the 1st group consisting of two negative lens elements, the 2nd group consisting of two positive lens elements, and the 3rd group, and the 1st group and 2nd group are moved at the time of zooming. Further, the ratio of the refractive indexes phiI and phiII of the 1st and 2nd groups, the ratio of the refractive index phiI of the 1st group and the composite focal length fW of the whole system on the wide-angle end, the ratio of the focal lengths fZP and fZR of the two positive lens elements of the 2nd group, and the ratio of the mean Abbe numbers of the two positive lenses and two negative lenses constituting cemented lenses of the 2nd group are set within specific ranges. Thus, the negative,negative, and positive constitution is employed and the refractive indexes, focal lengths, and Abbe numbers are set within the specific ranges, so variable power of 3 times and a F number of >=1.0 are realized and the overall length of the lens is shortened to reduce the weight.
JP20850887A 1987-08-07 1987-08-22 Compact zoom lens with large aperture ratio Pending JPS6452112A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP20850887A JPS6452112A (en) 1987-08-22 1987-08-22 Compact zoom lens with large aperture ratio
US07/230,173 US5009491A (en) 1987-08-07 1988-08-08 Compact zoom lens system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20850887A JPS6452112A (en) 1987-08-22 1987-08-22 Compact zoom lens with large aperture ratio

Publications (1)

Publication Number Publication Date
JPS6452112A true JPS6452112A (en) 1989-02-28

Family

ID=16557320

Family Applications (1)

Application Number Title Priority Date Filing Date
JP20850887A Pending JPS6452112A (en) 1987-08-07 1987-08-22 Compact zoom lens with large aperture ratio

Country Status (1)

Country Link
JP (1) JPS6452112A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008070519A (en) * 2006-09-13 2008-03-27 Canon Inc Zoom lens and imaging apparatus having the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008070519A (en) * 2006-09-13 2008-03-27 Canon Inc Zoom lens and imaging apparatus having the same

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