US 11,754,820 B2
Zoom optical system, optical apparatus and imaging apparatus using the zoom optical system, and method for manufacturing the zoom optical system
Kosuke Machida, Tokyo (JP)
Assigned to Nikon Corporation, Tokyo (JP)
Filed by Nikon Corporation, Tokyo (JP)
Filed on Feb. 16, 2022, as Appl. No. 17/673,244.
Application 17/673,244 is a division of application No. 16/345,123, granted, now 11,294,157, previously published as PCT/JP2016/084393, filed on Nov. 21, 2016.
Prior Publication US 2022/0171175 A1, Jun. 2, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 15/173 (2006.01); G02B 15/14 (2006.01); G02B 15/20 (2006.01); G02B 9/14 (2006.01); G02B 27/64 (2006.01)
CPC G02B 15/173 (2013.01) [G02B 9/14 (2013.01); G02B 15/143105 (2019.08); G02B 15/20 (2013.01); G02B 27/646 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A zoom optical system comprising, in order from an object:
a first lens group having a positive refractive power;
a second lens group having a negative refractive power;
a third lens group having a positive refractive power; and
a subsequent lens group, wherein
upon zooming, a distance between the first lens group and the second lens group changes, a distance between the second lens group and the third lens group changes, and a distance between the third lens group and the subsequent lens group changes,
upon zooming from a wide-angle end state to a telephoto end state, the first lens group moves toward the object,
the subsequent lens group comprises a focusing lens group that moves upon focusing,
the subsequent lens group comprises a fourth lens group having a positive refractive power, which is disposed closest to an object in the subsequent lens group, and
following conditional expressions are satisfied,
1.80<f1/fw<3.50
3.20<f1/f3<4.60
where
f1: a focal length of the first lens group,
fw: a focal length of the zoom optical system in a wide-angle end state, and
f3: a focal length of the third lens group.