Zooming optical system, optical apparatus, and manufacturing method for the zooming optical system
AssigneeNikon Corporation
InventorTomoki ITO
Life of this patent
Estimating the term…
Abstract
A zooming optical system comprises, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power. Upon zooming, distances between adjacent lens groups of the first to the fifth lens groups change respectively. The zooming optical system further satisfies the conditional expression 9.6<ft/(−f2)<20.0, where ft denotes a focal length of the zooming optical system in a telephoto end state, and f2 denotes a focal length of the second lens group.
Claims13
A zooming optical system comprising, in order from an object:
- a first lens group having positive refractive power;
- a second lens group having negative refractive power;
- a third lens group having positive refractive power;
- a fourth lens group having negative refractive power;
- and
- a fifth lens group having positive refractive power,
- wherein, upon zooming, distances between adjacent lens groups of the first to the fifth lens groups change respectively, and
- the following conditional expression is satisfied:
- 9.6<ft/(−f2)<20.0
- where
- ft:
- denotes a focal length of the zooming optical system in a telephoto end state, and
- f2 denotes a focal length of the second lens group.
A manufacturing method for a zooming optical system, comprising:
- arranging, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power and a fifth lens group having positive refractive power,
- wherein, upon zooming, distances between adjacent lens groups of the first to the fifth lens groups change respectively, and
- the following conditional expression is satisfied:
- 9.6<ft/(−f2)<20.0
- where
- ft:
- denotes a focal length of the zooming optical system in a telephoto end state,
- f2 denotes a focal length of the second lens group.
Dependencies are inferred from the claim text.