Zoom optical system, optical apparatus and method for manufacturing the zoom optical system
AssigneeNikon Corporation
InventorKosuke MACHIDA
Life of this patent
Estimating the term…
Abstract
A zoom optical system (ZL) comprises, in order from an object, a first lens group (G1) having a positive refractive power, a second lens group (G2) having a negative refractive power, a third lens group (G3) having a positive refractive power, a fourth lens group (G4) having a positive refractive power and a succeeding lens group (GR). In the zoom optical system, upon zooming, distances between adjacent lens groups change, and the succeeding lens group (GR) includes a plurality of focusing lens groups that have positive refractive powers and move upon focusing.
Claims16
1-22. (canceled)
A zoom optical system, comprising, in order from an object:
- a first lens group having a positive refractive power;
- a second lens group having a negative refractive power;
- a third lens group having a positive refractive power;
- a fourth lens group having a positive refractive power;
- and a succeeding lens group, wherein
- upon zooming, distances between adjacent lens groups change,
- the succeeding lens group includes a focusing lens group that moves upon focusing and disposed on the most object side, and
- the following conditional expression is satisfied:
- 3.4
- <
- f
-
- 1
- /
- (
- -
- f
-
- 2
- )
- <
- 7
- .
- 0
-
- 0
- where
- f1:
- a focal length of the first lens group, and
- f2:
- a focal length of the second lens group.
A method for manufacturing a zoom optical system, comprising:
- arranging in a lens barrel, in order from an object:
- a first lens group having a positive refractive power;
- a second lens group having a negative refractive power;
- a third lens group having a positive refractive power;
- a fourth lens group having a positive refractive power;
- and a succeeding lens group,
- the arranging being such that upon zooming, distances between adjacent lens groups change,
- the succeeding lens group including a focusing lens group that moves upon focusing and disposed on the most object side, and
- satisfying the following conditional expression:
- 3.4
- <
- f
-
- 1
- /
- (
- -
- f
-
- 2
- )
- <
- 7
- .
- 0
-
- 0
- where
- f1:
- a focal length of the first lens group,
- f2:
- a focal length of the second lens group.
Dependencies are inferred from the claim text.