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1. (WO2018185869) VARIABLE MAGNIFICATION OPTICAL SYSTEM, OPTICAL DEVICE, AND PRODUCTION METHOD FOR VARIABLE MAGNIFICATION OPTICAL SYSTEM

Pub. No.:    WO/2018/185869    International Application No.:    PCT/JP2017/014196
Publication Date: Fri Oct 12 01:59:59 CEST 2018 International Filing Date: Thu Apr 06 01:59:59 CEST 2017
IPC: G02B 15/20
G02B 13/18
Applicants: NIKON CORPORATION
株式会社ニコン
Inventors: MACHIDA, Kosuke
町田 幸介
Title: VARIABLE MAGNIFICATION OPTICAL SYSTEM, OPTICAL DEVICE, AND PRODUCTION METHOD FOR VARIABLE MAGNIFICATION OPTICAL SYSTEM
Abstract:
The present invention is capable of reducing the weight of a focusing lens group by satisfying a prescribed conditional formula and being provided with, in order from the object side, a first lens group having a negative refractive power, a first intermediate lens group having a positive refractive power, a second intermediate lens group having a negative refractive power, and a rear lens group, wherein when varying magnification from the wide-angle end state to the telephoto end state, the spacing between the first lens group and the first intermediate lens group changes, the spacing between the first intermediate lens group and the second intermediate lens group changes, and the spacing between the second intermediate lens group and the rear lens group changes, and the rear lens group is provided with one or more focusing lens groups which move when focusing from an object at infinity to an object at close range and at least one lens component which is further on the image side than the focusing lens group furthest on the image side from among the focusing lens groups.