Zoom optical system, optical device and method for manufacturing the zoom optical system
A first lens group (G 1 ) having positive refractive power, a front-side lens group (GX), an intermediate lens group (GM) having positive refractive power, and a rear-side lens group (GR) are arranged in order from an object side. The front-side lens group (GX) is composed of one or more lens groups and has a negative lens group At least part of the intermediate lens group (GM) is a focusing lens group (GF). The rear-side lens group (GR) is composed of one or more lens groups. Upon zooming, the first lens group (G 1 ) is moved with respect to an image surface, a distance between the first lens group (G 1 ) and the front-side lens group (GX) is changed, a distance between the front-side lens group (GX) and the intermediate lens group (GM) is changed, and a distance between the intermediate lens group (GM) and the rear-side lens group (GR) is changed.
1. A zoom optical system comprising in order from an object side:
a first lens group having positive refractive power,
a front-side lens group,
an intermediate lens group having positive refractive power, and
a rear-side lens group, wherein
the front-side lens group is composed of one or more lens groups and has a negative lens group,
the intermediate lens group is composed of one or more lens groups,
at least part of the intermediate lens group is a focusing lens group,
the rear-side lens group is composed of one or more lens groups,
upon zooming, the first lens group is moved with respect to an image surface, a distance between the first lens group and the front-side lens group is changed, a distance between the front-side lens group and the intermediate lens group is changed, and a distance between the intermediate lens group and rear-side lens group is changed,
a vibration-proof lens group that is disposed closer to an image than the focusing lens group, and is configured to be movable with a displacement component in a direction orthogonal to an optical axis, and
the following conditional expression is satisfied:
−15.00< fV/fRF< 10.000
where, fV denotes a focal length of the vibration-proof lens group, and
fRF denotes a focal length of a lens group closest to an object in the rear-side lens group.
2. The zoom optical system according to claim 1 , wherein the following conditional expressions are satisfied:
−0.150< DVW/fV< 1.000
32.000 ≤Wω
where, DVW denotes a distance between the vibration-proof lens group and a next lens in the wide angle end state,
Wω denotes half angle of the view in the wide angle end state.
3. The zoom optical system according to claim 1 , further comprising the rear-side lens group is composed of two or more lens groups.
4. The zoom optical system according to claim 1 , wherein the following conditional expressions are satisfied:
0.001<( DMRT−DMRW )/ fF< 1.000
32.000≤ Wω
Tω≤ 20.000
where, DMRW denotes a distance between the intermediate lens group and a lens group closest to an object in the rear-side lens group in the wide angle end state,
DMRT denotes a distance between the intermediate lens group and a lens group closest to an object in the rear-side lens group in the telephoto end state,
fF denotes a focal length of the focusing lens group,
Wω denotes a half angle of view in the wide angle end state, and
Tω denotes a half angle of view in the telephoto end state.
5. The zoom optical system according to claim 1 , wherein the lens group closest to the image in the front-side lens group includes an aperture stop and a lens that is disposed next to an image side of the aperture stop and has a convex surface facing the object side.
6. The zoom optical system according to claim 1 , wherein the following conditional expressions are satisfied:
−1.000< DVW/fV< 1.000
32.000≤ Wω
0.010< fF/fXR< 10.000
where, DVW denotes a distance between the vibration-proof lens group and a next lens in the wide angle end state,
Wω denotes a half angle of view in the wide angle end state,
fF denotes a focal length of the focusing lens group, and
fXR denotes a focal length of a lens group closest to an image in the front-side lens group.
7. The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:
0.010< fF/fW< 8.000
where, fF denotes a focal length of the focusing lens group, and
fW denotes a focal length of the entire system in the wide angle end state.
8. The zoom optical system according to claim 1 , wherein the following conditional expressions are satisfied:
0.010< fF/fXR< 10.000
0.100< DGXR/fXR< 1.500
where, fF denotes a focal length of the focusing lens group,
fXR denotes a focal length of a lens group closest to an image in the front-side lens group, and
DGXR denotes a thickness of a lens group closest to an image in the front-side lens group on an optical axis.
9. The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:
−20.000< fF/fV< 20.000
where, fF denotes a focal length of the focusing lens group.
10. The zoom optical system according to claim 1 , wherein the following conditional expressions are satisfied:
−1.000< DVW/fV< 1.000
32.000≤ Wω
0.010< fF/fXR< 10.000
0.100< DGXR/fXR< 1.500
where, DVW denotes a distance between the vibration-proof lens group and a next lens in the wide angle end state,
Wω denotes a half angle of view in the wide angle end state,
fF denotes a focal length of the focusing lens group,
fXR denotes a focal length of a lens group closest to an image in the front-side lens group, and
DGXR denotes a thickness of a lens group closest to an image in the front-side lens group on an optical axis.
11. The zoom optical system according to claim 1 , wherein at least part of the lens group closest to an object in the rear-side lens group is the vibration-proof lens group.
12. The zoom optical system according to claim 1 , wherein
a vibration-proof lens group disposed between the focusing lens group and a lens disposed closest to the image surface is provided,
the vibration-proof lens group is movable with a displacement component in a direction orthogonal to an optical axis,
a lens surface closest to an object in the focusing lens group is convex toward the object side, and
the following conditional expressions are satisfied:
0.000<( rB+rA )/( rB−rA )<1.000
0.000<( rC+rB )/( rC−rB )<10.000
where, rA denotes a radius of curvature of a lens surface facing a lens surface closest to an object in the focusing lens group with a distance in between, and
rB denotes a radius of curvature of the lens surface closest to an object in the focusing lens group, and
rC denotes a radius of curvature of the lens surface closest to the image surface in the focusing lens group.
13. The zoom optical system according to claim 1 , wherein
a vibration-proof lens group disposed between the focusing lens group and a lens disposed closest to the image surface is provided,
the vibration-proof lens group is movable with a displacement component in a direction orthogonal to an optical axis, and
the following conditional expression is satisfied:
1.050<( rB+rA )/( rB−rA )
where, rA denotes a radius of curvature of a lens surface facing a lens surface closest to an object in the focusing lens group with a distance in between, and
rB denotes a radius of curvature of the lens surface closest to an object in the focusing lens group.
14. The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:
32.000≤ Wω
where, Wω denotes a half angle of view in the wide angle end state.
15. The zoom optical system according to claim 1 , wherein the following conditional expression is satisfied:
Tω≤ 20.000
where, Tω denotes a half angle of view in the telephoto end state.
16. The zoom optical system according to claim 1 , wherein in the intermediate lens group is moved with respect to the image surface upon zooming.
17. The zoom optical system according to claim 1 , wherein the lens group closest to the image in the front-side lens group is moved with respect to the image surface upon zooming.
18. The zoom optical system according to claim 1 , wherein the lens group closest to an object in the rear-side lens group is moved with respect to the image surface upon zooming.
19. An optical device comprising the zoom optical system according to claim 1 .
20. The method for manufacturing a zoom optical system comprising in order from an object side, a first lens group having positive refractive power, a front-side lens group, an intermediate lens group having positive refractive power, and a rear-side lens group, wherein
the front-side lens group is composed of one or more lens groups and has a negative lens group,
the intermediate lens group is composed of one or more lens groups,
at least part of the intermediate lens group is a focusing lens group,
the rear-side lens group is composed of one or more lens groups, and
lenses are arranged in a lens barrel in a manner that upon zooming, the first lens group is moved with respect to an image surface, a distance between the first lens group and the front-side lens group is changed, a distance between the front-side lens group and the intermediate lens group is changed, and a distance between the intermediate lens group and rear-side lens group is changed,
a vibration-proof lens group that is disposed closer to an image than the focusing lens group, and is configured to be movable with a displacement component in a direction orthogonal to an optical axis, and
the following conditional expression is satisfied:
−15.00< fV/fRF< 10.000
where, fV denotes a focal length of the vibration-proof lens group, and
fRF denotes a focal length of a lens group closest to an object in the rear-side lens group.