Zoom optical system, optical apparatus and method for manufacturing the zoom optical system

A zoom optical system comprising, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a rear lens group, wherein

• lens groups forming the first lens group, the second lens group, and the rear lens group are arranged such that upon zooming, all these lens groups move and respective distances between the lens groups adjacent to each other change,
• the rear lens group comprises a third lens group having positive refractive power, which is disposed closest to an object in the rear lens group,
• the rear lens group comprises a last lens group which is disposed closest to an image,
• the rear lens group comprises a F lens group which is moved upon focusing, and
• the following conditional expressions are satisfied:
• −0.220<f1/fE<0.280
• 0.400<−f1/f2<1.200
• −0.500<f1/fF<0.700
• where
• f1:
• a focal length of the first lens group,
• f2:
• a focal length of the second lens group,
• fE:
• a focal length of the last lens group, and
• fF:
• a focal length of the F lens group.

A method for manufacturing a zoom optical system comprising, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a rear lens group,

• the method comprising either the following step A or the following step B,
• the step A is to dispose the first lens group, the second lens group and the rear lens group in a lens barrel so that:
• lens groups forming the first lens group, the second lens group, and the rear lens group are arranged such that upon zooming, respective distances between the lens groups adjacent to each other change,
• upon zooming from a wide-angle state to a telephoto state, the distance between the first lens group and the second lens group decreases,
• the rear lens group comprises a third lens group having positive refractive power, which is disposed closest to an object in the rear lens group,
• the zoom optical system further comprises a F lens group which is moved upon focusing, and
• the following conditional expressions are satisfied:
• −0.500<f1/fF<0.700
• 1.000<Bfw/fw<2.000
• −1.000<−f1/fRw<0.600
• where
• f1:
• a focal length of the first lens group,
• fF:
• a focal length of the F lens group,
• Bfw:
• back focus of the zoom optical system in a wide angle end state,
• fw:
• a focal length of the zoom optical system in the wide angle end state, and
• fRw:
• a focal length of the rear lens group in a wide angle end state, and
• the step B is to dispose the first lens group, the second lens group and the rear lens group in a lens barrel so that:
• lens groups forming the first lens group, the second lens group, and the rear lens group are arranged such that upon zooming, all these lens groups move and respective distances between the lens groups adjacent to each other change,
• the rear lens group comprises a third lens group having positive refractive power, which is disposed closest to an object in the rear lens group,
• the rear lens group comprises a last lens group which is disposed closest to an image,
• the rear lens group comprises a F lens group which is moved upon focusing, and
• the following conditional expressions are satisfied:
• −0.220<f1/fE<0.280
• 0.400<−f1/f2<1.200
• −0.500<f1/fF<0.700
• where
• f1:
• a focal length of the first lens group,
• f2:
• a focal length of the second lens group,
• fE:
• a focal length of the last lens group, and
• fF:
• a focal length of the F lens group.