US 12,085,701 B2
Zoom optical system, optical apparatus and method for manufacturing the zoom optical system
Takeshi Umeda, Fujisawa (JP); Tomoki Ito, Kawasaki (JP); and Atsushi Shibayama, Tokyo (JP)
Assigned to Nikon Corporation, Tokyo (JP)
Filed by Nikon Corporation, Tokyo (JP)
Filed on Oct. 6, 2021, as Appl. No. 17/495,657.
Application 17/495,657 is a continuation of application No. 16/334,023, granted, now 11,150,451, previously published as PCT/JP2017/036290, filed on Oct. 5, 2017.
Claims priority of application No. 2016-198641 (JP), filed on Oct. 7, 2016.
Prior Publication US 2022/0026694 A1, Jan. 27, 2022
Int. Cl. G02B 27/64 (2006.01); G02B 13/18 (2006.01); G02B 15/20 (2006.01)
CPC G02B 15/20 (2013.01) [G02B 13/18 (2013.01); G02B 27/646 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A zoom optical system comprising:
a first negative lens group having a negative refractive power,
a second negative lens group having a negative refractive power and disposed closer to an image than the first negative lens group, and
an object side lens group disposed on the object side with respect to the first negative lens group and having a positive refractive power,
wherein a distance between the first negative lens group and the second negative lens group and a distance between the object side lens group and the first negative lens group change during zooming,
at least part of the first negative lens group is movable so as to have a displacement component in a direction perpendicular to an optical axis,
at least part of the second negative lens group is movable along the optical axis during focusing, and
the following conditional expressions are satisfied:
0.50<fGb/fGa<2.60
0.30<|mda|/fw<2.30
where
fGa: a focal length of the first negative lens group,
fGb: a focal length of the second negative lens group,
|mda|: an absolute value of the amount of change in distance from a lens surface closest to an image in the object side lens group to a lens surface closest to an object in the first negative lens group on the optical axis during zooming from a wide angle end state to a telephoto end state, and
fw: a focal length of the zoom optical system in the wide angle end state.