Zoom lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorsDaiki Kawamura, Tetsuya Ori
Life of this patent
Estimating the term…
Abstract
The zoom lens consists of, in order from an object side, a first lens group that has a positive refractive power, a second lens group that has a negative refractive power, a middle group that includes one or more lens groups, and a final lens group. The middle group has a positive refractive power as a whole throughout an entire zoom range. During zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes. The zoom lens satisfies predetermined conditional expressions.
Claims53
A zoom lens consisting of, in order from an object side to an image side:
- a first lens group that has a positive refractive power;
- a second lens group that has a negative refractive power;
- a middle group that includes one or more lens groups;
- and a final lens group that has a negative refractive power,
- wherein the middle group has a positive refractive power as a whole throughout an entire zoom range,
- the middle group includes, in consecutive order from a position closest to the object side to the image side, a PA lens group that has a positive refractive power and a fourth lens group that has a positive refractive power,
- during zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes,
- all spacings of adjacent lens groups in the middle group change during zooming,
- the first lens group consists of one negative lens and two positive lenses,
- the PA lens group includes three positive lenses,
- exactly one focusing group that moves along an optical axis during focusing is disposed in the zoom lens,
- the focusing group has a negative refractive power and consists of one negative lens and one positive lens,
- a vibration-proof group that moves in a direction intersecting with an optical axis during image blur correction is disposed in the zoom lens, and
- the vibration-proof group has a negative refractive power and consists of one positive lens and two negative lenses,
- a maximum image height is IH,
- a focal length of the zoom lens in a state in which an infinite distance object is in focus at a telephoto end is ft,
- a refractive index of the negative lens of the first lens group at a d line is N1n,
- a focal length of the second lens group is f2,
- a focal length of the PA lens group is fPA,
- a focal length of the first lens group is f1, and
- Conditional Expressions (1), (13-3), (24-2), and (32-3) are satisfied, which are represented by
- 0.011<IH/ft<0.042 (1)
- 0.55<N1n<1.77 (13-3)
- 0.45<|f2|/fPA<0.83 (24-2)
- 3.384≤f1/|f2|<4.8 (32-3).
Dependencies are inferred from the claim text.