Patent ID: 11269164

Abstract:
A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; and an RN lens group (GRN) having a negative refractive power, wherein upon zooming, distances between the front lens group and the M1 lens group, between the M1 lens group and the M2 lens group, and between the M2 lens group and the RN lens group change, upon focusing from an infinite distant object to a short distant object, the RN lens group moves, the RN lens group comprises at least one lens having a positive refractive power, and at least one lens having a negative refractive power, and following conditional expressions are satisfied, 2.70<fFP/(−fFN)<4.50, 0.25<(−fF)/f1<0.45, where fFP: a focal length of a lens having a strongest positive refractive power in the RN lens group, fFN: a focal length of a lens having a strongest negative refractive power in the RN lens group, fF: a focal length of the RN lens group, and f1: a focal length of the front lens group.