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

A zoom optical system consisting of a first lens group having negative refractive power and a rear group comprising at least one lens group, which are arranged in order from an object side along an optical axis, wherein

• distances between the lens groups adjacent to each other change at zooming,
• the first lens group is fixed with respect to an image surface during zooming,
• all lens groups in the rear group move along the optical axis during zooming, and
• the following conditional expressions are satisfied:
• 2.
• <
• TLt
• /
• IHw
• <
• 3.
• 1.
• 00
• <
• (
• -
• f
• ⁢
• 1
• )
• /
• fRw
• <
• 1.5
• where
• TLt:
• an entire length of the zoom optical system in a telephoto end state,
• IHw:
• a maximum image height of the zoom optical system in a wide-angle end state,
• f1:
• a focal length of the first lens group, and
• fRw:
• a focal length of the rear group in the wide-angle end state.

A method for manufacturing a zoom optical system consisting of a first lens group having negative refractive power and a rear group comprising at least one lens group, which are arranged in order from an object side along an optical axis, the method comprising one of the following steps A or B, wherein

• the step A comprises disposing the lens groups in a lens barrel so that:
• distances between the lens groups adjacent to each other change at zooming,
• the first lens group is fixed with respect to an image surface during zooming,
• the at least one lens group in the rear group includes a final lens group having positive refractive power and disposed closest to an image side in the rear group, and
• the following conditional expressions are satisfied:
• 0.
• 1
• ⁢
• 5
• <
• ft
• /
• fGE
• <
• 0.5
• ⁢
• 0.8
• <
• (
• -
• fl
• )
• /
• fw
• >
• 1.27
• where
• ft:
• a focal length of the zoom optical system in a telephoto end state,
• fGE:
• a focal length of the final lens group,
• f1:
• a focal length of the first lens group, and
• fw:
• a focal length of the zoom optical system in a wide-angle end state, and
• the step B comprises disposing the lens groups in a lens barrel so that:
• distances between the lens groups adjacent to each other change at zooming,
• the first lens group is fixed with respect to an image surface during zooming,
• all lens groups in the rear group move along the optical axis during zooming, and
• the following conditional expressions are satisfied:
• 2.
• <
• TLt
• /
• IHw
• <
• 3.
• 1.
• <
• (
• -
• f
• ⁢
• 1
• )
• /
• fRw
• <
• 1.5
• where
• TLt:
• an entire length of the zoom optical system in the telephoto end state,
• IHw:
• a maximum image height of the zoom optical system in a wide-angle end state,
• f1:
• a focal length of the first lens group, and
• fRw:
• a focal length of the rear group in the wide-angle end state.