Optical system, optical device, and method for manufacturing optical system

Abstract

The invention provides an optical system, an optical apparatus, and a manufacturing method of the optical system, which can realize miniaturization / light weight and obtain good optical performance. An optical system (OL) for an optical device such as a camera (1) is provided with, in order from the object side, 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 negative refractive power, and a fifth lens group (G5) having a positive refractive power. When magnification is varied, the interval between adjacent lens groups varies, and when magnification is varied, the second lens group (G2) is fixed with respect to the image plane, and conditions based on a predetermined conditional expression are satisfied.

Description

Technical Field

[0001] The invention relates to an optical system, an optical device and a method for manufacturing the optical system. Background Art

[0002] Conventionally, a compact zoom lens has been proposed (for example, see Patent Document 1). However, there is a demand for further miniaturization and weight reduction, and further improvement in optical performance.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2016 / 157340 Summary of the invention

[0006] The optical system according to the first aspect of the present invention comprises, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein when zooming, the intervals between adjacent lens groups change, and when zooming, the second lens group is fixed relative to the image plane, and the optical system satisfies the following condition: 4.000<f1 / f3<10.000 in, f1: focal length of the first lens group, f3: focal length of the third lens group.

[0007] The optical system according to the second aspect of the present invention comprises, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein when the magnification is changed, the intervals between the adjacent lens groups change, and the optical system satisfies the following condition: 4.000<f1 / f3<10.000 4.000<TLw / fw<8.000 in, f1: focal length of the first lens group, f3: focal length of the 3rd lens group, fw: focal length of the entire optical system at the wide-angle end, TLw: The total optical length of the optical system in the wide-angle end state.

[0008] The first aspect of the present invention relates to a method for manufacturing an optical system, wherein the optical system comprises, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein the optical system is configured such that the intervals between adjacent lens groups change when the magnification is changed, the second lens group is configured such that when the magnification is changed, the second lens group is fixed relative to the image plane, and the optical system is configured such that the following conditions are satisfied: 4.000<f1 / f3<10.000 in, f1: focal length of the first lens group, f3: focal length of the third lens group.

[0009] A second aspect of the present invention relates to a method for manufacturing an optical system, wherein the optical system comprises, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein the optical system is arranged so that the intervals between adjacent lens groups change when the magnification is changed, and the optical system is arranged so as to satisfy the following condition: 4.000<f1 / f3<10.000 4.000<TLw / fw<8.000 in, f1: focal length of the first lens group, f3: focal length of the 3rd lens group, fw: focal length of the entire optical system at the wide-angle end, TLw: The total optical length of the optical system in the wide-angle end state. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a cross-sectional view showing the lens structure of the optical system according to the first embodiment.

[0011] Figure 2 1 and 10 are diagrams showing various aberrations of the optical system according to the first embodiment when an object at infinity is in focus. (a) shows a wide-angle end state, and (b) shows a telephoto end state.

[0012] Figure 3 It is a cross-sectional view showing the lens structure of the optical system according to the second embodiment.

[0013] Figure 4 1 and 10 are diagrams showing various aberrations of the optical system according to the second embodiment when an object at infinity is in focus, wherein (a) shows a wide-angle end state and (b) shows a telephoto end state.

[0014] Figure 5 It is a cross-sectional view showing the lens structure of the optical system according to the third embodiment.

[0015] Figure 6 1 and 10 are diagrams showing various aberrations of the optical system according to the third embodiment when an object at infinity is in focus, wherein (a) shows a wide-angle end state and (b) shows a telephoto end state.

[0016] Figure 7 It is a cross-sectional view showing the lens structure of the optical system involved in the fourth embodiment.

[0017] Figure 8 1 and 12 are diagrams showing various aberrations of the optical system according to the fourth embodiment when an object at infinity is in focus, wherein (a) shows a wide-angle end state and (b) shows a telephoto end state.

[0018] Fig. 9 It is a cross-sectional view of a camera equipped with the above-mentioned optical system.

[0019] Fig.10 This is a flowchart for explaining the method for manufacturing the optical system according to the first embodiment.

[0020] Fig.11 It is a flowchart for explaining the manufacturing method of the above-mentioned optical system involved in the second embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, preferred embodiments will be described with reference to the drawings.

[0022] (First embodiment)

[0023] like Figure 1 As shown, the optical system OL involved in the first embodiment is composed of a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with negative optical power, and a fifth lens group G5 with positive optical power in order from the object side. In addition, when the optical system OL is changed in magnification, the intervals between adjacent lens groups change, and the second lens group G2 is fixed relative to the image plane. By configuring in this way, the optical system OL can be miniaturized / lightened, and good optical performance can be obtained.

[0024] The optical system OL according to the first embodiment preferably satisfies the following conditional expression (1).

[0025] 4.000<f1 / f3<10.000 (1) in, f1: Focal length of the first lens group G1 f3: Focal length of the third lens group G3

[0026] Conditional expression (1) specifies the ratio of the focal length of the first lens group G1 to the focal length of the third lens group G3. By satisfying the conditional expression (1), the optical system OL can be miniaturized / lightened, and good optical performance can be obtained. If the upper limit value of the conditional expression (1) is exceeded, the focal length of the third lens group G3 becomes shorter, that is, the optical power of the third lens group G3 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of the conditional expression (1) more reliable, it is more preferred to set the upper limit value of the conditional expression (1) to 8.000, and further to 7.000. In addition, if it is lower than the lower limit value of the conditional expression (1), the focal length of the first lens group G1 becomes shorter, that is, the optical power of the first lens group G1 becomes too strong, and the change during the magnification correction of the field curvature becomes difficult, so it is not preferred. In order to make the effect of the conditional expression (1) more reliable, it is more preferable to set the lower limit value of the conditional expression (1) to 4.900, and further to 5.200.

[0027] (Second embodiment)

[0028] like Figure 1 As shown, the optical system OL involved in the second embodiment is composed of a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with negative optical power, and a fifth lens group G5 with positive optical power in sequence from the object side. In addition, when the optical system OL is changed in magnification, the intervals between adjacent lens groups change. By configuring in this way, the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained.

[0029] The optical system OL according to the second embodiment preferably satisfies the above-mentioned conditional expression (1). The effects and the like obtained by satisfying the conditional expression (1) are as described above.

[0030] In addition, the optical system OL according to the second embodiment preferably satisfies the following conditional expression (2).

[0031] 4.000<TLw / fw<8.000 (2) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity TLw: The total optical length of the optical system OL at the wide-angle end when focusing on an object at infinity

[0032] Conditional formula (2) specifies the ratio of the total optical length to the focal length of the entire system of the optical system OL in the wide-angle end state. By satisfying this conditional formula (2), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of conditional formula (2) is exceeded, the total optical length in the wide-angle end state becomes longer, resulting in that the focal length of the second lens group G2 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of this conditional formula (2) more reliable, it is more preferred to set the upper limit value of conditional formula (2) to 7.000, and further to 6.000. In addition, if it is lower than the lower limit value of conditional formula (2), the total optical length in the wide-angle end state becomes shorter, resulting in that the focal length of the first lens group G1 becomes too strong, and the change during the magnification correction of the field curvature becomes difficult, so it is not preferred. In addition, in order to make the effect of this conditional formula (2) more reliable, it is more preferred to set the lower limit value of conditional formula (2) to 4.200, and further to 4.400.

[0033] (Regarding the First Embodiment and the Second Embodiment)

[0034] In addition, the optical system OL according to the first embodiment and the second embodiment (hereinafter referred to as “the present embodiment”) preferably satisfies the following conditional expression (3).

[0035] 0.500<(-f2) / f3<3.000 (3) in, f2: Focal length of the second lens group G2 f3: Focal length of the third lens group G3

[0036] Conditional formula (3) specifies the ratio of the focal length of the second lens group G2 to the focal length of the third lens group G3. By satisfying the conditional formula (3), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of the conditional formula (3) is exceeded, the focal length of the third lens group G3 becomes shorter, that is, the optical power of the third lens group G3 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of the conditional formula (3) more reliable, it is more preferred to set the upper limit value of the conditional formula (3) to 1.500, and further to 1.300. In addition, if it is lower than the lower limit value of the conditional formula (3), the focal length of the second lens group G2 becomes shorter, that is, the optical power of the second lens group G2 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In order to make the effect of the conditional expression (3) more reliable, it is more preferable to set the lower limit value of the conditional expression (3) to 0.600, and further to 0.700.

[0037] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (4).

[0038] 0.400<f2 / f4<2.000 (4) in, f2: Focal length of the second lens group G2 f4: Focal length of the 4th lens group G4

[0039] Conditional expression (4) specifies the ratio of the focal length of the second lens group G2 to the focal length of the fourth lens group G4. By satisfying the conditional expression (4), the optical system OL can be miniaturized / lightened, and good optical performance can be obtained. If the upper limit value of the conditional expression (4) is exceeded, the focal length of the fourth lens group G4 becomes shorter, that is, the optical power of the fourth lens group G4 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of the conditional expression (4) more reliable, it is more preferred to set the upper limit value of the conditional expression (4) to 1.000, and further to 0.800. In addition, if it is lower than the lower limit value of the conditional expression (4), the focal length of the second lens group G2 becomes shorter, that is, the optical power of the second lens group G2 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In order to make the effect of the conditional expression (4) more reliable, it is more preferable to set the lower limit value of the conditional expression (4) to 0.470, and further to 0.490.

[0040] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (5).

[0041] 4.000<f1 / (-f2)<8.000 (5) in, f1: Focal length of the first lens group G1 f2: Focal length of the second lens group G2

[0042] Conditional expression (5) specifies the ratio of the focal length of the first lens group G1 to the focal length of the second lens group G2. By satisfying the conditional expression (5), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of the conditional expression (5) is exceeded, the focal power of the second lens group G2 becomes too strong, and as a result, the focal power of the fourth lens group G4 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of the conditional expression (5) more reliable, it is more preferred to set the upper limit value of the conditional expression (5) to 7.500, and further to 7.000. In addition, if it is lower than the lower limit value of the conditional expression (5), the focal power of the first lens group G1 becomes too strong, and as a result, the focal power of the second lens group G2 becomes too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In order to make the effect of the conditional expression (5) more reliable, it is more preferable to set the lower limit value of the conditional expression (5) to 4.500, and further to 5.000.

[0043] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (6).

[0044] 0.100<(-f2) / f5<0.800 (6) in, f2: Focal length of the second lens group G2 f5: Focal length of the fifth lens group G5

[0045] Conditional expression (6) specifies the ratio of the focal length of the second lens group G2 to the focal length of the fifth lens group G5. By satisfying the conditional expression (6), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of the conditional expression (6) is exceeded, the focal power of the fifth lens group G5 becomes too strong, resulting in the focal power of the third lens group G3 becoming too strong, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of the conditional expression (6) more reliable, it is more preferred to set the upper limit value of the conditional expression (6) to 0.500, and further to 0.400. In addition, if it is lower than the lower limit value of the conditional expression (6), the focal power of the second lens group G2 becomes too strong, resulting in the focal power of the fifth lens group G5 becoming too strong, and the change during the magnification correction of the field curvature becomes difficult, so it is not preferred. In order to make the effect of conditional expression (6) more reliable, it is more preferable to set the lower limit value of conditional expression (6) to 0.200, and further to 0.240.

[0046] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (7).

[0047] 0.100<f3 / f5<0.480 (7) in, f3: Focal length of the third lens group G3 f5: Focal length of the fifth lens group G5

[0048] Conditional expression (7) specifies the ratio of the focal length of the third lens group G3 to the focal length of the fifth lens group G5. By satisfying the conditional expression (7), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of the conditional expression (7) is exceeded, the focal length of the fifth lens group G5 becomes shorter, that is, the optical power of the fifth lens group G5 becomes too strong, and it becomes difficult to correct the change of the image plane curvature during zooming, so it is not preferred. In addition, in order to make the effect of the conditional expression (7) more reliable, it is more preferred to set the upper limit value of the conditional expression (7) to 0.420, and further to 0.400. In addition, if it is lower than the lower limit value of the conditional expression (7), the focal length of the third lens group G3 becomes shorter, that is, the optical power of the third lens group G3 becomes too strong, and it becomes difficult to correct the spherical aberration in the telephoto end state, so it is not preferred. In order to make the effect of conditional expression (7) more reliable, it is more preferable to set the lower limit value of conditional expression (7) to 0.200, and further to 0.250.

[0049] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (8).

[0050] 4.000<f1 / fw<8.000 (8) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity f1: Focal length of the first lens group G1

[0051] Conditional expression (8) specifies the ratio of the focal length of the first lens group G1 to the focal length of the entire optical system OL in the wide-angle end state. By satisfying this conditional expression (8), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of conditional expression (8) is exceeded, the focal length of the first lens group G1 becomes longer, and as a result, the optical power of the third lens group G3 becomes stronger in order to perform zooming by the third lens group G3, and the correction of spherical aberration in the telephoto end state becomes difficult, so it is not preferred. In addition, in order to make the effect of conditional expression (8) more reliable, it is more preferred to set the upper limit value of conditional expression (8) to 7.500, and further to 7.000. In addition, if it is lower than the lower limit value of conditional expression (8), the focal length of the first lens group G1 becomes shorter, that is, the optical power of the first lens group G1 becomes too strong, and it becomes difficult to correct the change of image curvature during zooming, so it is not preferred. Furthermore, in order to make the effect of conditional expression (8) more reliable, it is more preferable to set the lower limit value of conditional expression (8) to 4.500.

[0052] In the optical system OL according to the present embodiment, it is preferable that the first lens group G1 is composed of two lenses. With such a configuration, the optical system OL can be made smaller and lighter, and good optical performance can be obtained.

[0053] In the optical system OL according to the present embodiment, it is preferable that the fourth lens group G4 is configured to move along the optical axis during focusing. With such a configuration, it is possible to reduce aberration fluctuations during focusing.

[0054] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (9).

[0055] 0.100<(D34t-D34w) / fw<0.800 (9) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity D34w: Axial air gap between the third lens group G3 and the fourth lens group G4 at the wide-angle end when focusing on an object at infinity D34t: Axial air space between the third lens group G3 and the fourth lens group G4 at the telephoto end when focusing on an object at infinity

[0056] Conditional formula (9) specifies the ratio of the change in the axial air gap between the third lens group G3 and the fourth lens group G4 when zooming from the wide-angle end state to the telephoto end state relative to the focal length of the entire optical system OL in the wide-angle end state. By satisfying this conditional formula (9), good optical performance during focusing can be obtained. In addition, in order to make the effect of conditional formula (9) more reliable, it is more preferable to set the upper limit value of conditional formula (9) to 0.700. In addition, in order to make the effect of conditional formula (9) more reliable, it is more preferable to set the lower limit value of conditional formula (9) to 0.300.

[0057] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (10).

[0058] 0.800<|f12w| / fw<1.500 (10) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity f12w: The combined focal length of the first lens group G1 and the second lens group G2 at the wide-angle end when focusing on an object at infinity.

[0059] Conditional expression (10) specifies the ratio of the composite focal length of the first lens group G1 and the second lens group G2 to the focal length of the entire optical system OL in the wide-angle end state. By satisfying this conditional expression (10), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. If the upper limit value of conditional expression (10) is exceeded, the composite focal length of the front group composed of the first lens group G1 and the second lens group G2 in the wide-angle end state becomes longer, that is, the optical power of the front group becomes too weak, and the correction of coma in the wide-angle end state becomes difficult, so it is not preferred. In addition, in order to make the effect of conditional expression (10) more reliable, it is more preferred to set the upper limit value of conditional expression (10) to 1.300, and further to 1.250. In addition, if it is lower than the lower limit value of conditional expression (10), the composite focal length of the front group becomes shorter, that is, the optical power of the front group becomes too strong, and the correction of distortion in the wide-angle end state becomes difficult, so it is not preferred. In order to make the effect of conditional expression (10) more reliable, it is more preferable to set the lower limit value of conditional expression (10) to 0.900, or further to 1.000.

[0060] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (11).

[0061] 0.100<Bfw / fw<2.000 (11) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity Bfw: The back focal length of the optical system OL at the wide-angle end when focusing on an object at infinity (length in terms of air)

[0062] The conditional expression (11) specifies the ratio of the back focal length to the focal length of the entire system of the optical system OL in the wide-angle end state. By satisfying the conditional expression (11), it is possible to achieve miniaturization / lightweighting of the optical system OL and obtain good optical performance. In addition, the conditional expression (11) is further set to be more reliable, and it is more preferable to set the upper limit value of the conditional expression (11) to 1.200, and further to 1.000. In addition, in order to make the effect of the conditional expression (11) more reliable, it is more preferable to set the lower limit value of the conditional expression (11) to 0.500, and further to 0.600.

[0063] In addition, in the optical system OL involved in the present embodiment, it is preferred that at least a portion of the third lens group G3 is an anti-shake group Gvr, and the anti-shake group Gvr moves in a manner having a component in a direction orthogonal to the optical axis. By configuring in this way, the optical system OL can be miniaturized / lightened, and good optical performance can be obtained.

[0064] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (12).

[0065] 1.000<|fvr| / f3<6.000 (12) in, f3: Focal length of the third lens group G3 fvr: focal length of the image stabilization group Gvr

[0066] Conditional expression (12) specifies the ratio of the focal length of the anti-shake group Gvr to the focal length of the third lens group G3. By satisfying conditional expression (12), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. In addition, in order to make the effect of conditional expression (12) more reliable, it is more preferable to set the upper limit value of conditional expression (12) to 3.000. In addition, in order to make the effect of conditional expression (12) more reliable, it is more preferable to set the lower limit value of conditional expression (12) to 1.300.

[0067] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (13).

[0068] 0.200<(D23w / TLw)×(ft / fw)<1.500 (13) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity ft: The focal length of the entire optical system OL at the telephoto end when focusing on an object at infinity TLw: The total optical length of the optical system OL at the wide-angle end when focusing on an object at infinity D23w: Axial air space between the second lens group G2 and the third lens group G3 at the wide-angle end when focusing on an object at infinity

[0069] Conditional formula (13) specifies the relationship between the total optical length of the optical system OL in the wide-angle end state and the ratio of the axial air space between the second lens group G2 and the third lens group G3, and the zoom ratio of the optical system OL. By satisfying the conditional formula (13), spherical aberration and image curvature can be well corrected from the wide-angle end state to the telephoto end state. In addition, in order to make the effect of the conditional formula (13) more reliable, it is more preferable to set the upper limit value of the conditional formula (13) to 1.200. In addition, in order to make the effect of the conditional formula (13) more reliable, it is more preferable to set the lower limit value of the conditional formula (13) to 0.300.

[0070] In the optical system OL according to the present embodiment, it is preferable that the fifth lens group G5 includes an aspherical lens having an inflection point (hereinafter referred to as “specific aspherical lens Las”) and satisfies the following conditional expression (14).

[0071] 0.000<fw / |fg5as|<0.500 (14) in, fw: The focal length of the entire optical system OL at the wide-angle end when focusing on an object at infinity fg5as: Focal length of the specific aspherical lens Las included in the fifth lens group G5

[0072] Conditional expression (14) specifies the ratio of the focal length of the entire optical system OL in the wide-angle end state to the focal length of the aspheric lens (specific aspheric lens Las) with an inflection point provided by the fifth lens group G5. By configuring the aspheric lens (specific aspheric lens Las) with an inflection point satisfying conditional expression (14) in the fifth lens group G5, spherical aberration and image curvature can be well corrected from the wide-angle end state to the telephoto end state. In addition, in order to make the effect of conditional expression (14) more reliable, it is more preferable to set the upper limit value of conditional expression (14) to 0.300.

[0073] In addition, the optical system OL according to the present embodiment preferably satisfies the following conditional expression (15).

[0074] 30.00°<ωw<60.00° (15) in, ωw: Half angle of view of the optical system OL at the wide-angle end

[0075] Conditional formula (15) specifies the appropriate range of the half-angle of view of the optical system OL in the wide-angle end state. By satisfying the conditional formula (15), the miniaturization / lightweighting of the optical system OL can be achieved, and good optical performance can be obtained. In addition, in order to make the effect of the conditional formula (15) more reliable, it is more preferable to set the upper limit value of the conditional formula (15) to 50.00°. In addition, in order to make the effect of the conditional formula (15) more reliable, it is more preferable to set the lower limit value of the conditional formula (15) to 42.00°, and further to 43.00°.

[0076] In addition, the optical system OL involved in this embodiment makes the first lens group G1 miniaturized by moving the first lens group G1 when changing the magnification, and by fixing two of the five lens groups relative to the image plane I when changing the magnification, it is possible to reduce the driving force required to move the lens groups when changing the magnification.

[0077] Next, based on Fig. 9A camera as an optical device having an optical system OL according to the present embodiment is described. The camera 1 is a so-called mirrorless camera of a lens-interchangeable type having an optical system OL according to the present embodiment as a photographic lens 2. In the camera 1, light from an object (subject) not shown is condensed by the photographic lens 2, and a subject image is formed on a photographing surface of a photographing unit 3 via an OLPF (Optical Low Pass Filter) not shown. Then, the subject image is photoelectrically converted by a photoelectric conversion element (photographing element) provided on the photographing unit 3, thereby generating an image of the subject. The image is displayed on an EVF (Electronic View Finder) 4 provided on the camera 1. Thus, the photographer can observe the subject via the EVF 4.

[0078] Furthermore, when the photographer presses a release button (not shown), an image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can photograph a subject using the camera 1. In the present embodiment, an example of a mirrorless camera is described, but even when the optical system OL of the present embodiment is mounted on a single-lens reflex camera having a quick return mirror on the camera body and observing the subject through a viewfinder optical system, the same effect as that of the above-mentioned camera 1 can be achieved.

[0079] In addition, the contents described below can be appropriately adopted within the range not impairing the optical performance.

[0080] In the present embodiment, an optical system OL of a 5-group structure is shown, but the above structural conditions and the like can also be applied to other group structures such as 6-group and 7-group structures. In addition, it is also possible to have a structure in which a lens or a lens group is added to the side closest to the object, or a structure in which a lens or a lens group is added to the side closest to the image plane. Specifically, consider a structure in which a lens group whose position relative to the image plane is fixed when changing the magnification or focusing is added to the side closest to the image plane. In addition, the so-called lens group, unless a boundary is specifically specified, refers to a portion having at least one lens separated by an air gap that changes when changing the magnification or focusing. In addition, a lens component refers to a single lens or a joined lens formed by joining a plurality of lenses.

[0081] In addition, a single lens group or a plurality of lens groups or a part of lens groups may be used as a focus group, and the focus group moves along the optical axis direction to focus from an infinitely distant object to a close-distance object. In this case, the focus group may also be applied to autofocus, and is also suitable for motor drive (such as an ultrasonic motor) for autofocus. It is particularly preferred to use the fourth lens group G4 as the focus group, and the positions of the other lenses relative to the image plane are fixed during focusing.

[0082] Alternatively, the lens group or part of the lens group may be used as an anti-shake group, and the anti-shake group may move in a manner having a displacement component in a direction orthogonal to the optical axis, or may rotate (swing) in a direction within a plane including the optical axis to correct image shake caused by hand shake. It is particularly preferred that at least a part of the third lens group G3 be used as an anti-shake group.

[0083] In addition, the lens surface can be formed by a spherical surface or a plane, or it can be formed by an aspherical surface. In the case where the lens surface is a spherical surface or a plane, lens processing and assembly adjustment become easy, and it is possible to prevent the degradation of optical performance caused by errors in processing and assembly adjustment, so it is preferred. In addition, even in the case of deviation of the image plane, the degradation of the drawing performance is small, so it is preferred. In the case where the lens surface is an aspherical surface, the aspherical surface can be any of an aspherical surface processed by grinding, a glass molded aspherical surface in which glass is formed into an aspherical shape by a mold, and a composite aspherical surface in which resin is formed into an aspherical shape on the surface of the glass. In addition, the lens surface can be a diffraction surface, and the lens can also be a refractive index distribution lens (GRIN lens) or a plastic lens.

[0084] The aperture stop S is preferably disposed on the object side of the third lens group G3 , but a member serving as the aperture stop may be omitted and a lens frame may be used instead to perform its function.

[0085] Furthermore, in order to reduce glare and ghosting and realize high optical performance with high contrast, an antireflection coating having high transmittance in a wide wavelength range may be applied to each lens surface.

[0086] In addition, the variable magnification ratio of the variable magnification optical system ZL of the present embodiment is approximately 2 to 5 times.

[0087] The conditions and structures described above each exert the above-mentioned effects, and are not limited to satisfying all the conditions and structures. The above-mentioned effects can be obtained even if any condition or structure, or any combination of conditions or structures, is satisfied.

[0088] Below, refer to Fig.10 The following is an overview of the manufacturing method of the optical system OL according to the first embodiment. First, a first lens group G1 having positive optical power, a second lens group G2 having negative optical power, a third lens group G3 having positive optical power, a fourth lens group G4 having negative optical power, and a fifth lens group G5 having positive optical power are prepared in order from the object side (step S100). Next, the lens groups are configured so that the intervals between adjacent lens groups change when the magnification is changed (step S200), and the second lens group G2 is configured so that the second lens group G2 is fixed relative to the image plane when the magnification is changed (step S300). Then, these lens groups are configured so as to satisfy a specified condition (for example, the above-mentioned conditional expression (1)) (step S400).

[0089] In addition, refer to Fig.11 The following is an overview of the manufacturing method of the optical system OL according to the second embodiment. First, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having negative power, and a fifth lens group G5 having positive power are prepared in order from the object side (step S100). Next, the lens groups are arranged so that the intervals between adjacent lens groups change when the magnification is changed (step S200). Then, the lens groups are arranged so as to satisfy the prescribed conditions (for example, the above-mentioned conditional expressions (1) and (2)) (step S300).

[0090] Thus, it is possible to provide an optical system, an optical device, and a method for manufacturing the optical system, which can achieve miniaturization and weight reduction and obtain good optical performance.

[0091] Example

[0092] Hereinafter, each embodiment will be described based on the accompanying drawings. Figure 1 , Figure 3 , Figure 5 and Figure 7 The cross-sectional views are sectional views showing the structure and focal power distribution of the optical systems OL (OL1 to OL4) involved in each embodiment. In addition, in the cross-sectional views of the optical systems OL1 to OL4, arrows are used to indicate the movement direction of each lens group along the optical axis when changing the magnification from the wide-angle end state (W) to the telephoto end state (T) and when focusing from an infinitely distant object (∞) to a close-distance object.

[0093] In each embodiment, regarding the aspheric surface, when the height in the direction perpendicular to the optical axis is set to y, the distance along the optical axis from the tangent plane of the vertex of each aspheric surface to each aspheric surface at the height y (the amount of concavity) is set to S(y), the curvature radius (paraxial curvature radius) of the reference spherical surface is set to r, the conic constant is set to K, and the n-order aspheric coefficient is set to An, it is expressed by the following formula (a). In addition, in the following embodiments, "En" means "×10 -n ”.

[0094] S(y)=(y 2 / r) / {1+(1-K×y 2 / r 2 ) 1 / 2}+A4×y 4 +A6×y 6 +A8×y 8 +A10×y 10 (a)

[0095] In each example, the secondary aspheric coefficient A2 is 0. In the table of each example, an aspheric surface is indicated by an aspheric surface number on the right side thereof.

[0096] [First embodiment]

[0097] Figure 1 1 is a diagram showing the structure of an optical system OL1 according to the first embodiment. The optical system OL1 is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power, in order from the object side.

[0098] The first lens group G1 is composed of one lens component, and is composed of a cemented positive lens formed by cementing, in order from the object side, a negative lens L11 of a meniscus shape with a convex surface facing the object side and a positive lens L12 of a meniscus shape with a convex surface facing the object side. In addition, the second lens group G2 is composed of, in order from the object side, a negative lens L21 of a meniscus shape with a convex surface facing the object side and an aspherical lens surface on the object side, a negative lens L22 of a biconcave shape, a positive lens L23 of a biconvex shape, and a negative lens L24 of a meniscus shape with a concave surface facing the object side. In addition, the third lens group G3 is composed of, in order from the object side, a biconvex positive lens L31, a cemented negative lens formed by cementing a biconvex positive lens L32 and a biconcave negative lens L33, a meniscus positive lens L34 with a convex surface facing the object side, a cemented negative lens formed by cementing a meniscus positive lens L35 with a concave surface facing the object side and a biconcave negative lens L36, and a biconvex positive lens L37 with a lens surface on the object side and a lens surface on the image side formed in an aspherical shape. In addition, the fourth lens group G4 is composed of a biconcave negative lens L41 with a lens surface on the image side formed in an aspherical shape. In addition, the fifth lens group G5 is composed of, in order from the object side, a meniscus positive lens L51 (specific aspheric lens Las) with a lens surface on the object side and a lens surface on the image side formed in an aspheric shape and a concave surface facing the object side near the optical axis, and a meniscus positive lens L52 with a concave surface facing the object side.

[0099] When the optical system OL1 changes magnification from the wide-angle end state to the telephoto end state, the intervals between adjacent lens groups change. In addition, when the optical system OL1 changes magnification from the wide-angle end state to the telephoto end state, the second lens group G2 and the fifth lens group G5 are fixed relative to the image plane I, and the first lens group G1, the third lens group G3 and the fourth lens group G4 move along the optical axis toward the object side.

[0100] When the optical system OL1 focuses from an object at infinity to an object at a short distance, the fourth lens group G4 moves toward the image plane.

[0101] In the optical system OL1, the aperture stop S is disposed between the second lens group G2 and the third lens group G3 (on the object side of the third lens group G3), and moves along the optical axis together with the third lens group G3 when zooming.

[0102] In addition, in the optical system OL1, by using the cemented negative lens formed by cementing the positive lens L35 and the negative lens L36 of the third lens group G3 as the anti-shake lens group Gvr, and moving the anti-shake lens group Gvr in a manner having a displacement component in a direction orthogonal to the optical axis, correction of the image position (anti-shake) when hand shake occurs is performed.

[0103] In the following Table 1, the values ​​of the parameters of the optical system OL1 are recorded. In this Table 1, f shown in the overall parameters is the focal length of the entire system, FNO is the F value, ω is the half field angle [°], Y is the maximum image height, TL is the total optical length, and BF is the back focal length, which represents the values ​​of the wide-angle end state, the intermediate focal length state, and the telephoto end state when the infinitely distant object is focused. Here, the back focal length BF represents the distance on the optical axis from the lens surface closest to the image plane (the 30th surface) to the image plane I in terms of the air conversion length. In addition, the total optical length TL represents the length obtained by adding the back focal length in terms of the air conversion length to the distance on the optical axis from the lens surface closest to the object side (the 1st surface) to the lens surface closest to the image plane side (the 30th surface). In addition, the first column m in the lens data indicates the order of the lens surfaces from the object side along the direction of light travel (surface number), the second column r indicates the radius of curvature of each lens surface, the third column d indicates the distance on the optical axis from each optical surface to the next optical surface (surface spacing), the fourth column nd and the fifth column νd indicate the refractive index and Abbe number for the d line (λ=587.6nm). In addition, the radius of curvature ∞ indicates a plane, and the refractive index of air 1.00000 is omitted. In addition, the focal length of the lens group shows the surface number and focal length of the starting surface of each lens group.

[0104] Here, the focal length f, radius of curvature r, surface spacing d, and other lengths recorded in all the following parameter values ​​are generally expressed in "mm", but the optical system can obtain the same optical performance even if it is scaled up or scaled down, so it is not limited to this. In addition, the description of these symbols and the description of the parameter table are the same in the subsequent embodiments.

[0105] (Table 1) First embodiment

[0106] [Overall parameters]

[0107] [Lens data]

[0108] [Focal length of lens group]

[0109] In the optical system OL1, the 4th, 23rd, 24th, 26th, 27th and 28th surfaces are formed aspherical. Table 2 shows the data of the aspherical surface at the surface number m, that is, the values ​​of the cone constant K and the aspherical constants A4 to A10.

[0110] (Table 2)

[0111] In addition, in the optical system OL1, the axial air space D3 between the first lens group G1 and the second lens group G2, the axial air space D11 between the second lens group G2 and the aperture stop S, the axial air space D24 between the third lens group G3 and the fourth lens group G4, the axial air space D26 between the fourth lens group G4 and the fifth lens group G5, and the back focal length BF change when the magnification is changed. In the following Table 3, the variable intervals of the wide-angle end state, the intermediate focal length state, and the telephoto end state when the object is focused on at infinity and the object is focused on at a close distance are shown. In addition, D0 represents the distance from the lens surface (first surface) on the object side of the optical system OL1 to the object, f represents the focal length, and β represents the photographic magnification. This description is also the same in the subsequent embodiments.

[0112] (Table 3)

[0113] [Variable interval data]

[0114] exist Figure 2 , a spherical aberration diagram, an astigmatism diagram, a distortion diagram, a magnification chromatic aberration diagram, and a coma diagram of the optical system OL1 when an infinitely distant object is focused. Figure 2 In the figure, (a) shows the wide-angle end state, and (b) shows the telephoto end state. In each aberration diagram, FNO represents the F value, and Y represents the image height. In addition, the spherical aberration diagram shows the value of the F value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum value of the image height, and the coma diagram shows the value of each image height. d represents the d line (λ=587.6nm), and g represents the g line (λ=435.8nm). In the astigmatism diagram and the coma diagram, the solid line represents the sagittal image plane, and the dotted line represents the meridional image plane. In addition, in the aberration diagrams of the various embodiments shown later, the same symbols as those of the present embodiment are also used. It can be seen from these aberration diagrams that the optical system OL1 corrects various aberrations well and has excellent imaging performance.

[0115] [Second embodiment]

[0116] Figure 3 1 is a diagram showing the structure of an optical system OL2 according to the second embodiment. The optical system OL2 is composed of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power.

[0117] The first lens group G1 is composed of one lens component, and is composed of a cemented positive lens formed by cementing a negative lens L11 having a meniscus shape with a convex surface facing the object side and a positive lens L12 having a meniscus shape with a convex surface facing the object side in order from the object side. In addition, the second lens group G2 is composed of a negative lens L21 having a meniscus shape with a convex surface facing the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a negative lens L24 having a meniscus shape with a concave surface facing the object side in order from the object side. In addition, the third lens group G3 is composed of a biconvex positive lens L31, a cemented negative lens formed by cementing a positive lens L32 having a biconvex shape and a negative lens L33 having a biconcave shape, a positive lens L34 having a meniscus shape with a convex surface facing the object side, and a cemented positive lens formed by cementing a positive lens L35 having a biconvex shape and a negative lens L36 having a concave surface facing the object side in order from the object side. In addition, the fourth lens group G4 is composed of, in order from the object side, a positive lens L41 of a meniscus shape with a concave surface facing the object side, and a negative lens L42 of a biconcave shape with a lens surface on the object side formed in an aspherical shape. In addition, the fifth lens group G5 is composed of, in order from the object side, a positive lens L51 of a meniscus shape with a concave surface facing the object side near the optical axis (specific aspherical lens Las), and a positive lens L52 of a meniscus shape with a concave surface facing the object side.

[0118] When the optical system OL2 changes magnification from the wide-angle end state to the telephoto end state, the intervals between adjacent lens groups change. In addition, when the optical system OL2 changes magnification from the wide-angle end state to the telephoto end state, the second lens group G2 and the fifth lens group G5 are fixed relative to the image plane I, and the first lens group G1, the third lens group G3 and the fourth lens group G4 move along the optical axis toward the object side.

[0119] When the optical system OL2 focuses from an object at infinity to an object at a short distance, the fourth lens group G4 moves toward the image plane.

[0120] In the optical system OL2, the aperture stop S is arranged between the second lens group G2 and the third lens group G3 (on the object side of the third lens group G3), and moves along the optical axis together with the third lens group G3 when zooming.

[0121] In the following Table 4, the values ​​of the parameters of the optical system OL2 are recorded. Figure 3 In the figure, the 23rd surface is an imaginary surface.

[0122] (Table 4) Second embodiment

[0123] [Overall parameters]

[0124] [Lens data]

[0125] [Focal length of lens group]

[0126] In the optical system OL2, the 4th surface, the 26th surface, the 28th surface, and the 29th surface are formed into aspherical shapes. The following Table 5 shows the data of the aspherical surface at the surface number m, that is, the values ​​of the cone constant K and the aspherical constants A4 to A10.

[0127] (Table 5)

[0128] In addition, in the optical system OL2, the axial air space D3 between the first lens group G1 and the second lens group G2, the axial air space D11 between the second lens group G2 and the aperture stop S, the axial air space D23 between the third lens group G3 and the fourth lens group G4, the axial air space D27 between the fourth lens group G4 and the fifth lens group G5, and the back focal length BF change when the magnification is changed. In the following Table 6, the variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state when the infinitely distant object is focused and the close-distance object is focused are shown.

[0129] (Table 6)

[0130] [Variable interval data]

[0131] exist Figure 4 , a spherical aberration diagram, an astigmatism diagram, a distortion diagram, a magnification chromatic aberration diagram, and a coma diagram of the optical system OL2 when an infinitely distant object is focused. Figure 4 In FIG. 1 , (a) shows the wide-angle end state, and (b) shows the telephoto end state. As can be seen from these aberration diagrams, the optical system OL2 corrects various aberrations well and has excellent imaging performance.

[0132] [Third embodiment]

[0133] Figure 5 1 is a diagram showing the structure of an optical system OL3 according to the third embodiment. The optical system OL3 is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power, in order from the object side.

[0134] The first lens group G1 is composed of one lens component, and is composed of a cemented positive lens formed by cementing a negative lens L11 having a meniscus shape with a convex surface facing the object side and a positive lens L12 having a meniscus shape with a convex surface facing the object side in order from the object side. In addition, the second lens group G2 is composed of a negative lens L21 having a meniscus shape with a convex surface facing the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens L24 in order from the object side. In addition, the third lens group G3 is composed of a biconvex positive lens L31, a cemented positive lens formed by cementing a positive lens L32 having a biconvex shape and a negative lens L33 having a biconcave shape, a negative lens L34 having a meniscus shape with a convex surface facing the object side, and a cemented positive lens formed by cementing a positive lens L35 having a biconvex shape and a negative lens L36 having a concave surface facing the object side in order from the object side. In addition, the fourth lens group G4 is composed of a negative lens L41 with a biconcave shape whose lens surface on the object side is formed into an aspherical shape. In addition, the fifth lens group G5 is composed of a positive lens L51 (specific aspherical lens Las) with a meniscus shape whose lens surface on the object side and the lens surface on the image side are formed into an aspherical shape and whose concave surface is toward the object side near the optical axis, and a positive lens L52 with a biconvex shape, in order from the object side.

[0135] When the optical system OL3 changes magnification from the wide-angle end state to the telephoto end state, the intervals between adjacent lens groups change. In addition, when the optical system OL3 changes magnification from the wide-angle end state to the telephoto end state, the second lens group G2 and the fifth lens group G5 are fixed relative to the image plane I, and the first lens group G1, the third lens group G3 and the fourth lens group G4 move along the optical axis toward the object side.

[0136] When the optical system OL3 focuses from an object at infinity to an object at a short distance, the fourth lens group G4 moves toward the image plane.

[0137] In the optical system OL3, the aperture stop S is arranged between the second lens group G2 and the third lens group G3 (on the object side of the third lens group G3), and moves along the optical axis together with the third lens group G3 when zooming.

[0138] In addition, in the optical system OL3, the image position is corrected (anti-shake) when hand shake occurs by using the joined positive lens formed by joining the positive lens L35 and the negative lens L36 of the third lens group G3 as the anti-shake lens group Gvr, and moving the anti-shake lens group Gvr in a manner having a displacement component in a direction orthogonal to the optical axis.

[0139] In the following Table 7, the values ​​of the parameters of the optical system OL3 are described.

[0140] (Table 7) Example 3

[0141] [Overall parameters]

[0142] [Lens data]

[0143] [Focal length of lens group]

[0144] In the optical system OL3, the 4th surface, the 23rd surface, the 25th surface, and the 26th surface are formed into aspherical shapes. The following Table 8 shows the data of the aspherical surface at the surface number m, that is, the values ​​of the cone constant K and the aspherical constants A4 to A10.

[0145] (Table 8)

[0146] In addition, in the optical system OL3, the axial air space D3 between the first lens group G1 and the second lens group G2, the axial air space D11 between the second lens group G2 and the aperture stop S, the axial air space D22 between the third lens group G3 and the fourth lens group G4, the axial air space D24 between the fourth lens group G4 and the fifth lens group G5, and the back focal length BF change when the magnification is changed. In the following Table 9, the variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state when the infinitely distant object is focused and the close-distance object is focused are shown.

[0147] (Table 9)

[0148] [Variable interval data]

[0149] exist Figure 6 The spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma diagram of the optical system OL3 when an infinitely distant object is focused are shown in FIG. Figure 6In FIG. 1 , (a) shows the wide-angle end state, and (b) shows the telephoto end state. As can be seen from these aberration diagrams, the optical system OL3 corrects various aberrations well and has excellent imaging performance.

[0150] [Fourth embodiment]

[0151] Figure 7 1 is a diagram showing the structure of an optical system OL4 according to Example 4. The optical system OL4 is composed of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power.

[0152] The first lens group G1 is composed of one lens component, and is composed of a cemented positive lens formed by cementing a negative lens L11 having a meniscus shape with a convex surface facing the object side and a positive lens L12 having a biconvex shape in order from the object side. In addition, the second lens group G2 is composed of a negative lens L21 having a meniscus shape with a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, and a negative lens L24 having a meniscus shape with a concave surface facing the object side, in order from the object side. In addition, the third lens group G3 is composed of, in order from the object side, a biconvex positive lens L31, a cemented negative lens formed by cementing a biconvex positive lens L32 and a biconcave negative lens L33, a meniscus positive lens L34 with a convex surface facing the object side, a cemented negative lens formed by cementing a meniscus positive lens L35 with a concave surface facing the object side and a biconcave negative lens L36, and a biconvex positive lens L37 with a lens surface on the object side and a lens surface on the image side formed in an aspherical shape. In addition, the fourth lens group G4 is composed of a biconcave negative lens L41 with a lens surface on the image side formed in an aspherical shape. In addition, the fifth lens group G5 is composed of, in order from the object side, a meniscus positive lens L51 (specific aspheric lens Las) with a lens surface on the object side and a lens surface on the image side formed in an aspheric shape and a concave surface facing the object side near the optical axis, and a meniscus positive lens L52 with a concave surface facing the object side.

[0153] When the optical system OL4 changes magnification from the wide-angle end state to the telephoto end state, the intervals between adjacent lens groups change. In addition, when the optical system OL4 changes magnification from the wide-angle end state to the telephoto end state, the fifth lens group G5 is fixed relative to the image plane I, and the first lens group G1, the second lens group G2, the third lens group G3 and the fourth lens group G4 move along the optical axis toward the object side.

[0154] When the optical system OL4 focuses from an object at infinity to an object at a short distance, the fourth lens group G4 moves toward the image plane.

[0155] In the optical system OL4, the aperture stop S is arranged between the second lens group G2 and the third lens group G3 (on the object side of the third lens group G3), and moves along the optical axis together with the third lens group G3 when zooming.

[0156] In addition, in the optical system OL4, by using the cemented negative lens formed by cementing the positive lens L35 and the negative lens L36 of the third lens group G3 as the anti-shake lens group Gvr, and moving the anti-shake lens group Gvr in a manner having a displacement component in a direction orthogonal to the optical axis, correction of the image position (anti-shake) when hand shake occurs is performed.

[0157] In the following Table 10, the values ​​of the parameters of the optical system OL4 are described.

[0158] (Table 10) Example 4

[0159] [Overall parameters]

[0160] [Lens data]

[0161] [Focal length of lens group]

[0162] In the optical system OL4, the 4th, 23rd, 24th, 26th, 27th and 28th surfaces are formed into aspherical shapes. The following Table 11 shows the aspherical surface data at the surface number m, that is, the values ​​of the cone constant K and the aspherical constants A4 to A10.

[0163] (Table 11)

[0164] In addition, in the optical system OL4, the axial air space D3 between the first lens group G1 and the second lens group G2, the axial air space D11 between the second lens group G2 and the aperture stop S, the axial air space D24 between the third lens group G3 and the fourth lens group G4, the axial air space D26 between the fourth lens group G4 and the fifth lens group G5, and the back focal length BF change when the magnification is changed. In the following Table 12, the variable intervals in the wide-angle end state, the intermediate focal length state, and the telephoto end state when the infinitely distant object is focused and the close-distance object is focused are shown.

[0165] (Table 12)

[0166] [Variable interval data]

[0167] exist Figure 8 The spherical aberration diagram, astigmatism diagram, distortion diagram, magnification chromatic aberration diagram, and coma diagram of the optical system OL4 when an infinitely distant object is focused are shown in FIG. Figure 8 In FIG. 1 , (a) shows the wide-angle end state, and (b) shows the telephoto end state. As can be seen from these aberration diagrams, the optical system OL4 corrects various aberrations well and has excellent imaging performance.

[0168] [Conditional value]

[0169] Table 13 below shows the corresponding values ​​of conditional expressions (1) to (15) in the first to fourth embodiments.

[0170] (Table 13) (1) f1 / f3 (2) TLw / fw (3) (-f2) / f3 (4) f2 / f4 (5) f1 / (-f2) (6) (-f2) / f5 (7) f3 / f5 (8) f1 / fw (9) (D34t-D34w) / fw (10) |f12w| / fw (11) Bfw / fw (12) |fvr| / f3 (13) (D23w / TLw)×(ft / fw) (14) fw / |fg5as| (15) ωw[°]

[0171] Description of symbols 1 Camera (optical equipment) OL (OL1~OL4) Optical system G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group Gvr anti-shake group

Claims

1. An optical system, wherein: The optical system includes, in order from the object side, 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, When changing magnification, the intervals between adjacent lens groups change. When changing the magnification, the second lens group is fixed relative to the image plane. The optical system satisfies the following conditions: 4.000<f1 / f3<10.000 in, f1: focal length of the first lens group, f3: focal length of the third lens group.

2. An optical system, wherein: The optical system includes, in order from the object side, 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, When changing magnification, the intervals between adjacent lens groups change. The optical system satisfies the following conditions: 4.000<f1 / f3<10.000 4.000<TLw / fw<8.000 in, f1: focal length of the first lens group, f3: focal length of the 3rd lens group, fw: focal length of the entire optical system at the wide-angle end, TLw: The total optical length of the optical system in the wide-angle end state.

3. The optical system according to claim 1 or 2, wherein: The optical system satisfies the following conditions: 0.500<(-f2) / f3<3.000 in, f2: focal length of the second lens group, f3: focal length of the third lens group.

4. The optical system according to any one of claims 1 to 3, wherein: The optical system satisfies the following conditions: 0.400<f2 / f4<2.000 in, f2: focal length of the second lens group, f4: focal length of the fourth lens group.

5. The optical system according to any one of claims 1 to 4, wherein: The optical system satisfies the following conditions: 4.000<f1 / (-f2)<8.000 in, f1: focal length of the first lens group, f2: focal length of the second lens group.

6. The optical system according to any one of claims 1 to 5, wherein: The optical system satisfies the following conditions: 0.100<(-f2) / f5<0.800 in, f2: focal length of the second lens group, f5: focal length of the 5th lens group.

7. The optical system according to any one of claims 1 to 6, wherein: The optical system satisfies the following conditions: 0.100<f3 / f5<0.480 in, f3: focal length of the 3rd lens group, f5: focal length of the 5th lens group.

8. The optical system according to any one of claims 1 to 7, wherein: The optical system satisfies the following conditions: 4.000<f1 / fw<8.000 in, fw: focal length of the entire optical system at the wide-angle end, f1: focal length of the first lens group.

9. The optical system according to any one of claims 1 to 8, wherein: When focusing is performed, the fourth lens group moves along the optical axis.

10. The optical system according to any one of claims 1 to 9, wherein: The optical system satisfies the following conditions: 0.100<(D34t-D34w) / fw<0.800 in, fw: focal length of the entire optical system at the wide-angle end, D34w: the axial air space between the third lens group and the fourth lens group in the wide-angle end state, D34t: Axial air space between the third lens group and the fourth lens group in the telephoto end state.

11. The optical system according to any one of claims 1 to 10, wherein: The optical system satisfies the following conditions: 0.800<|f12w| / fw<1.500 in, fw: focal length of the entire optical system at the wide-angle end, f12w: The combined focal length of the first lens group and the second lens group in the wide-angle end state.

12. The optical system according to any one of claims 1 to 11, wherein: The optical system satisfies the following conditions: 0.100<Bfw / fw<2.000 in, fw: focal length of the entire optical system at the wide-angle end, Bfw: The back focal length of the optical system at the wide-angle end.

13. The optical system according to any one of claims 1 to 12, wherein: At least a part of the third lens group is an anti-vibration group, and the anti-vibration group moves so as to have a component in a direction orthogonal to the optical axis.

14. The optical system according to claim 13, wherein: The optical system satisfies the following conditions: 1.000<|fvr| / f3<6.000 in, f3: focal length of the 3rd lens group, fvr: Focal length of the image stabilization group.

15. The optical system according to any one of claims 1 to 14, wherein: The optical system satisfies the following conditions: 0.200<(D23w / TLw)×(ft / fw)<1.500 in, fw: focal length of the entire optical system at the wide-angle end, ft: the focal length of the entire optical system at the telephoto end state, TLw: The total optical length of the optical system at the wide-angle end, D23w: An axial air space between the second lens group and the third lens group in the wide-angle end state.

16. The optical system according to any one of claims 1 to 15, wherein: The fifth lens group includes an aspherical lens having an inflection point. The optical system satisfies the following conditions: 0.000<fw / |fg5as|<0.500 in, fw: focal length of the entire optical system at the wide-angle end, fg5as: focal length of the aspheric lens.

17. The optical system according to any one of claims 1 to 16, wherein: The optical system satisfies the following conditions: 30.00°<ωw<60.00° in, ωw: half field angle of the optical system in the wide-angle end state. 18 . An optical device comprising the optical system according to claim 1 .

19. A method for manufacturing an optical system, the optical system comprising, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein: The arrangement is such that the intervals between adjacent lens groups change when zooming. The second lens group is configured so that when zooming, the second lens group is fixed relative to the image plane. Configured to meet the following conditions: 4.000<f1 / f3<10.000 in, f1: focal length of the first lens group, f3: focal length of the third lens group.

20. A method for manufacturing an optical system, the optical system comprising, in order from the object side, a first lens group having positive optical power, a second lens group having negative optical power, a third lens group having positive optical power, a fourth lens group having negative optical power, and a fifth lens group having positive optical power, wherein: The arrangement is such that the intervals between adjacent lens groups change when zooming. Configured to meet the following conditions: 4.000<f1 / f3<10.000 4.000<TLw / fw<8.000 in, f1: focal length of the first lens group, f3: focal length of the 3rd lens group, fw: focal length of the entire optical system at the wide-angle end, TLw: The total optical length of the optical system in the wide-angle end state.

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