Variable magnification optical system, optical device, and method for manufacturing variable magnification optical system

A variable magnification optical system comprising, in order from the object side, a first negative lens group having negative refractive power, and a rear group including a plurality of lens groups,

• at varying magnification, the first negative lens group being fixed with respect to the image plane and the spacings between adjacent lens groups being varied,
• a third negative lens group being disposed closest to the object side among one or more lens groups having negative refractive power and disposed closer to the image plane side than the first positive lens group having positive refractive power and disposed closest to the object side in the plurality of lens groups included in the rear group,
• the variable magnification optical system satisfies the following conditional expression:
• 0.00<fA/fCβ<0.30
• where
• fA:
• the focal length of the first negative lens group
• fCβ:
• the focal length of the third negative lens group.

A method for manufacturing a variable magnification optical system, the method comprising configuring a variable magnification optical system including, in order from the object side, a first negative lens group having negative refractive power and a rear group including a plurality of lens groups so that

• at varying magnification, the first negative lens group being fixed with respect to the image plane and the spacings between adjacent lens groups being varied,
• an aperture stop being disposed closer to the image plane side than the first negative lens group,
• a second negative lens group disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups included in the rear group having negative refractive power, and
• the following conditional expression is satisfied:
• 0.00<fA/fCα<0.30
• where
• fA:
• the focal length of the first negative lens group
• fCα:
• the focal length of the second negative lens group.