TECHNICAL FIELD

The present invention relates to a zooming optical system, an optical apparatus and a manufacturing method for the zooming optical system.

TECHNICAL BACKGROUND

A zooming optical system suitable for a photographic cameras, electronic still cameras, video cameras or the like has been proposed (e.g. Patent Document 1). In recent years, requirements for preventing ghosts and flares, which would diminish optical performance, are becoming increasingly stricter for zooming optical systems suitable for photographic cameras, electronic still cameras, video cameras or the like, therefore higher performance is also demanded for an anti-reflection film formed on a lens surface, and to meet this demand, multilayer film designing technology and multilayer film deposition technology are continuously advancing (e.g. see Patent Document 2).

PRIOR ARTS LIST

Patent Document

Patent Document 1: Japanese Laid-Open Patent Publication No. 2009-180844(A)

Patent Document 2: Japanese Laid-Open Patent Publication No. 2000-356704(A)

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

A problem of a conventional zooming optical system is that aberration fluctuation upon zooming is considerable. Moreover, in the case of a conventional zooming optical system, reflected light that causes ghosts and flares is easily generated from optical surfaces, which affects optical performance.

With the foregoing in view, it is an object of the present invention to provide a zooming optical system and an optical apparatus that ideally suppresses aberration fluctuations upon zooming, and a manufacturing method for the zooming optical system.

It is another object of the present invention to provide a zooming optical system and an optical apparatus having a high optical performance to further decrease ghosts and flares, while ideally suppressing aberration fluctuations upon zooming, and a manufacturing method for the zooming optical system.

Means to Solve the Problems

To solve the above problems, a zooming optical system according to a first aspect of the present invention is constituted by, 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, and in this zooming optical system, the first lens group is moved along the optical axis upon zooming, at least a part of the second lens group to the fifth lens group being moved so as to include a component orthogonal to the optical axis, and the following conditional expressions are satisfied:
4.41<f1/(−f2)<5.33
2.15<f1/f3<4.95
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.18<f3/(−f4)<0.92
where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.82<(−f4)/f5<1.58
where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that an aperture stop is disposed in a position closer to the image than the second lens group.

In this zooming optical system, it is preferable that an aperture stop is disposed in a position between the third lens group and the fifth lens group.

In this zooming optical system, it is preferable that an aperture stop is disposed in a position between the third lens group and the fourth lens group.

In this zooming optical system, it is preferable that at least a part of the third lens group is moved along the optical axis upon focusing.

In this zooming optical system, it is preferable that a second lens group is fixed with respect to the image plane upon zooming.

In this zooming optical system, it is preferable that at least a part of the second lens group is moved so as to include a component orthogonal to the optical axis.

In this zooming optical system, it is preferable that all the lens surfaces are spherical.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.10<f3/f5<1.06
where f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.70<f1/(−f4)<2.55
where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.11<f2/f4<0.62
where f2 denotes a focal length of the second lens group, and f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that 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.

In the zooming optical system, it is preferable that the following conditional expression is satisfied:
3.9<ft/(−f4)<8.8
where ft denotes a focal length of the zooming optical system in the telephoto end state, and f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.8<(−f4)/f5<1.8
where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.3<(−f2)/f5<0.8
where f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
1.3<f1/(−f4)<3.0
where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
1.9<f1/f5<3.2
where f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.32<(−f4)/f5<1.93
where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.74<f1/(−f4)<2.82
where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.44<(−f2)/f3<0.86.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.32<(−f4)/f5<2.07
where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.29<f3/(−f4)<0.87
where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that an anti-reflection film including at least one layer formed by a wet process is formed on at least one surface of the optical surfaces.

It is preferable that the anti-reflection film is a multilayer film, and the outermost layer of the multilayer film is a layer formed by the wet process.

It is more preferable that the following conditional expression is satisfied:
nd≤1.30
where nd denotes a refractive index at d-line of the layer formed by the wet process.

An optical apparatus according to the first aspect of the present invention includes this zooming optical system for forming an object image on a predetermined image plane.

A zooming optical system according to a second aspect of the present invention is constituted by, 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, and in this zooming optical system, the first lens group is moved along the optical axis upon zooming, at least a part of the second lens group to the fifth lens group is moved so as to include a component orthogonal to the optical axis, and the following conditional expressions being satisfied:
4.41<f1/(−f2)<5.33
0.10<f3/f5<1.06
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f3 denotes a focal length of the third lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied: 0.70<f1/(−f4)<2.55 where f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.11<f2/f4<0.62
where f4 denotes a focal length of the fourth lens group.

An optical apparatus according to the second aspect of the present invention includes the zooming optical system according to the second aspect of the present invention for forming an object image on a predetermined image plane.

A zooming optical system according to a third aspect of the present invention is constituted by, 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, and in this zooming optical system, the second lens group is fixed with respect to the image plane upon zooming, and the following conditional expressions are satisfied:
9.6<ft/(−f2)<20.0
3.9<ft/(−f4)<8.8
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, and f4 denotes a focal length of the fourth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.8<(−f4)/f5<1.8
where f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.3<(−f2)/f5<0.8
where f5 denotes a focal length of the fifth lens group.

An optical apparatus according to the third aspect of the present invention includes the zooming optical system according to the third aspect of the present invention for forming an object image on a predetermined image plane.

A zooming optical system according to a fourth aspect of the present invention is constituted by, in order from the 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, and in this zooming optical system, the second lens group is fixed with respect to the image plane upon zooming, and the following conditional expressions are satisfied:
2.0<f1/(−f2)<6.1
1.3<f1/(−f4)<3.0
1.9<f1/f5<3.2
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.8<(−f4)/f5<1.8.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.3<(−f2)/f5<0.8.

An optical apparatus according to the fourth aspect of the present invention includes the zooming optical system according to the fourth aspect of the present invention for forming an object image on a predetermined image plane.

A zooming optical system according to the fifth aspect of the present invention is constituted by, 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, and in this zooming optical system, the second lens group and the fourth lens group are fixed with respect to the image plane upon zooming, and the following conditional expressions are satisfied:
1.05<f1/(−f2)<6.10
0.32<(−f4)/f5<1.93
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.74<f1/(−f4)<2.82.

An optical apparatus according to the fifth aspect of the present invention includes the zooming optical system according to the fifth aspect of the present invention for forming an object image on a predetermined image plane.

A zooming optical system according to a sixth aspect of the present invention is constituted by, 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, and in this zooming optical system, the second lens group and the fourth lens group are fixed with respect to the image plane upon zooming, and the following conditional expressions are satisfied:
0.44<(−f2)/f3<0.86
0.32<(−f4)/f5<2.07
where f2 denotes a focal length of the second lens group, f3 denotes a focal length of the third lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

In this zooming optical system, it is preferable that the following conditional expression is satisfied:
0.29<f3/(−f4)<0.87.

An optical apparatus according to the sixth aspect of the present invention includes the zooming optical system according to the sixth aspect of the present invention for forming an object image on a predetermined image plane.

A manufacturing method for a zooming optical system according to a first aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including: disposing the first lens group to move along the optical axis upon zooming; disposing the second lens group to the fifth lens group so that at least a part of the second lens group to the fifth lens group move so as to include a component orthogonal to the optical axis, and the following conditional expressions are satisfied:
4.41<f1/(−f2)<5.33
2.15<f1/f3<4.95
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group.

A manufacturing method for a zooming optical system according to a second aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including: disposing the first lens group to move along the optical axis upon zooming; disposing the second lens group to the fifth lens group so that at least a part of the second lens group to the fifth lens group move so as to include a component orthogonal to the optical axis, and the following conditional expressions are satisfied:
4.41<f1/(−f2)<5.33
0.10<f3/f5<1.06
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, and f3 denotes a focal length of the third lens group, and f5 denotes a focal length of the fifth lens group.

A manufacturing method for a zooming optical system according to a third aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including; disposing the second lens group to be fixed with respect to the image plane upon zooming, and the following conditional expressions being satisfied:
9.6<ft/(−f2)<20.0
3.9<ft/(−f4)<8.8
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, and f4 denotes a focal length of the fourth lens group.

A manufacturing method for a zooming optical system according to a fourth aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including: disposing the second lens group to be fixed with respect to the image plane upon zooming, and the following conditional expressions being satisfied:
2.0<f1/(−f2)<6.1
1.3<f1/(−f4)<3.0
1.9<f1/f5<3.2
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

A manufacturing method for a zooming optical system according to a fifth aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including: disposing the second lens group and the fourth lens group to be fixed with respect to the image plane upon zooming, and the following conditional expressions being satisfied:
1.05<f1/(−f2)<6.10
0.32<(−f4)/f5<1.93
where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

A manufacturing method for a zooming optical system according to a sixth aspect of the present invention is a manufacturing method for a zooming optical system constituted by, 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, the method including: disposing the second lens group and the fourth lens group to be fixed with respect to the image plane upon zooming, and the following conditional expressions being satisfied:
0.44<(−f2)/f3<0.86
0.32<(−f4)/f5<2.07
where f2 denotes a focal length of the second lens group, f3 denotes a focal length of the third lens group, f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group.

Advantageous Effects of the Invention

According to the present invention, a zooming optical system and an optical apparatus that ideally suppresses aberration fluctuations upon zooming, and a manufacturing method for the zooming optical system, can be provided.

According to another aspect of the present invention, a zooming optical system and an optical apparatus having a high optical performance to further decrease ghosts and flares while ideally suppressing aberration fluctuations upon zooming, and a manufacturing method for the zooming optical system, can be provided.

