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 |
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.
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