JP2014153675A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens having a high magnification capable of simultaneously achieving reduction in size and price while having high fidelity imaging performance.SOLUTION: A zoom lens has a first lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4, and all the lens groups move. The second lens group G2 has a negative lens 21, a negative lens 22, a positive lens 23 and a negative lens 24, and the third lens group G3 has a positive refractive power 3a group and a negative refractive power 3b group, and the fourth lens group G4 has a biconvex positive lens 41, a biconcave negative lens 42 and a biconvex positive lens 43, and the following conditions are fulfilled.

Description

  The present invention relates to a zoom lens, and more particularly to a high-power zoom lens.

  In recent years, zoom lenses with a high magnification exceeding 10 times have attracted attention as interchangeable lenses for single-lens reflex cameras (hereinafter referred to as “single-lens reflex cameras”). Such a zoom lens is required not only to have high-quality imaging performance, but also to be compact and inexpensive. With the expansion of the market for digital single-lens reflex cameras in Japan and overseas, the demand for these has become stronger. In particular, in the emerging markets, the supply of products for the middle class is increasing, and it is difficult to satisfy market requirements unless the zoom lens has even higher price competitiveness.

  The optical system of the zoom lens includes a plurality of lens groups, and the number of lenses constituting each lens group is large. Therefore, it is effective to reduce the glass material cost in order to reduce the price of the zoom lens. Specifically, it is conceivable to construct an optical system using a lens made of a low-cost glass material whose material cost is relatively low. However, when an optical system is configured using a lens made of low-cost glass material, there is a high possibility that the imaging performance is deteriorated. Therefore, in the optical design of the zoom lens, the most important thing is how to reduce the cost while suppressing the deterioration of the imaging performance under the constraints of the total optical length and the outer diameter of the lens barrel. Should. Further, when a glass material having a low refractive index is selected in order to promote cost reduction, the field curvature is significantly under-performed. In order to correct the curvature of field, it is necessary to increase the diameter of the lens, increase the number of lenses, and so on, so that an increase in the size of the optical system is inevitable in order to maintain high-quality imaging performance. In other words, the cost reduction of the optical system has a large contradiction to the improvement of the imaging performance and / or the compactness of the optical system, and it has been difficult to satisfy these requirements at the same time. Furthermore, there is a great demand for further downsizing of the zoom lens, and the optical design of the zoom lens has become extremely complicated.

  Here, as a prior art regarding the zoom lens, there are techniques disclosed in Patent Documents 1 to 3. The zoom lens disclosed in Patent Document 1 includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power in order from the object side to the image side. The lens group includes a fourth lens group having positive refractive power, and the plurality of lens groups move along the optical axis direction during zooming. Further, the second lens group functions as a focus lens, and the second lens group moves during focusing to adjust the focus position. In a zoom lens having such an optical system, in Patent Document 1, among the plurality of lenses constituting the second lens group, a negative lens located closest to the object side is defined as a second lens, and the material of the second lens is used. There has been proposed a zoom lens that satisfies the following conditions when the refractive index and Abbe number are n2a and ν2a, respectively.

−0.0125 * ν2a + 2.175 <n2a <−0.011 * ν2a + 2.21
42.0 <ν2a <59.0

  Patent Document 2 discloses, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive lens power. And a fourth lens group having a refracting power, and when zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, and the second lens group and the third lens group Each lens group moves along the optical axis direction so that the distance between the third lens group and the fourth lens group changes. The third lens group includes, in order from the object side, a front group having a positive refractive power and a rear group having a negative refractive power, and when camera shake occurs, only the rear group is in a direction substantially orthogonal to the optical axis. The image plane is corrected by moving it. A zoom lens having an image stabilization function that satisfies the following conditional expression is proposed, where fw is the focal length of the zoom lens in the wide-angle end state and f1 is the focal length of the first lens group.

  1.5 <f1 / fw <8.0

  Further, in Patent Document 3, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, And a fourth lens group having a refractive power of 5 mm, and when zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, and the second lens group and the third lens group Each lens group moves along the optical axis direction so that the distance between the third lens group and the fourth lens group decreases. The second lens group functions as a focus lens group, and the second lens group moves to the object side during focusing. In such an optical system, in Patent Document 3, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the third lens group is f3, and the focal length of the telephoto end of the entire optical system. A zoom lens having an anti-vibration function that satisfies the following conditions when the distance is ft has been proposed.

0.35 <f1 / ft <0.45
0.04 <| f2 | / ft <0.065
0.15 <f3 / ft <0.25

JP 2009-271471 A JP 2008-304952 A JP 2010-44103 A

  In the zoom lenses disclosed in Patent Document 1 and Patent Document 2 described above, cost reduction and weight reduction of the focus mechanism are achieved. Specifically, the invention described in Patent Document 1 is characterized in that, in the second lens group that moves at the time of focusing, a lens disposed on the most object side is a resin lens formed of a resin material. is there. Among the plurality of lenses constituting the second lens group, the lens arranged closest to the object side tends to have a larger lens diameter and weight than other lenses. By doing so, the weight of the second lens group can be reduced, which can contribute to high-speed AF (autofocus) and low power consumption. However, when the lens arranged closest to the object among the plurality of lenses constituting the second lens group is a resin lens, the refractive index of the resin material is generally lower than that of the glass material, so that the lens diameter is increased. Leads to. The enlargement of the lens diameter is not preferable from the viewpoint of realizing a compact zoom lens because it has a reciprocal relationship with the reduction of the filter diameter and the lens barrel diameter. Furthermore, the embodiment described in Patent Document 1 discloses only a zoom lens having a low magnification of about 4 times, and does not disclose a zoom lens having a high magnification exceeding 10 times.

  The zoom lens described in Patent Document 2 achieves high imaging performance while ensuring a high magnification ratio. However, both the filter diameter and the optical total length are large, and the level required by the present invention is not reached in terms of realizing compactness.

  The invention described in Patent Document 3 has high imaging performance while ensuring a high magnification ratio, and further, the size of the filter is reduced and the total optical length is shortened. However, the number of lenses constituting the optical system is large, and it does not reach the level required by the present invention in terms of realizing cost reduction.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens capable of simultaneously realizing compactness and low cost while having high-quality imaging performance in a high-magnification zoom lens.

  As a result of intensive studies, the present inventors have achieved the above object by adopting the following lens configuration.

  The zoom lens according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power in order from the object side as a lens group constituting the optical system. At least, and a fourth lens group having a positive refractive power, and all the lens groups constituting the optical system move along the optical axis direction so as to adjust the distance between them. The second lens group includes, in order from the object side, a negative lens having a convex surface on the object side, a negative lens, a positive lens, and a negative lens. The three lens group includes a 3a group having a positive refractive power and a 3b group having a negative refractive power. The 3a group includes a biconvex positive lens, a biconvex positive lens, and a negative lens in order from the object side. And the 3b group is relative to the optical axis during vibration isolation. The fourth lens group has at least three lenses, a biconvex positive lens, a biconcave negative lens, and a biconvex positive lens. The following conditional expressions (1) to (4) It is characterized by satisfying.

  In the zoom lens according to the present invention, it is preferable that the following conditional expression (5) is satisfied.

  In the zoom lens according to the present invention, it is preferable that the following conditional expression (6) is satisfied.

  In the zoom lens according to the present invention, it is preferable that the following conditional expression (7) is satisfied.

  In the zoom lens according to the present invention, it is preferable that the following conditional expression (8) is satisfied.

  In the zoom lens according to the present invention, during zooming, the distance between the first lens group and the second lens group increases from the wide-angle end to the telephoto end, and the distance between the second lens group and the third lens group. It is preferable that these lens groups move so that the distance between the third lens group and the fourth lens group is narrowed.

  In the zoom lens according to the present invention, at the time of zooming, the distance between the second lens group and the 3a group decreases from the wide-angle end to the telephoto end, the distance between the 3a group and the 3b group changes, and the 3b These lens groups may be moved so that the distance between the group and the fourth lens group is narrowed.

  In the zoom lens according to the present invention, as a lens group constituting the optical system, in addition to the first lens group to the fourth lens group, a fifth lens group following the fourth lens group is provided, From the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the third lens group and the These lens groups may move so that the distance between the fourth lens group is narrowed and the distance between the fourth lens group and the fifth lens group is widened.

  In the zoom lens according to the present invention, as a lens group constituting the optical system, in addition to the first lens group to the fourth lens group, a fixed lens or a fixed lens group may be provided on the most image side.

  In the zoom lens according to the present invention, it is preferable that the second lens group moves toward the object side from an infinite object distance to a close distance during focusing.

  In the zoom lens according to the present invention, it is preferable that the second lens group and / or the fourth lens group include at least one resin lens.

  By adopting the above-described configuration, the present invention can simultaneously achieve compactness and low price while having high-quality imaging performance in a high-magnification zoom lens.

It is sectional drawing which shows the structural example of the optical system of this invention, and shows an example of the lens structure at the time of infinity focusing in a wide angle end. FIG. 30 is an aberration diagram at the zoom wide-angle end of the zoom lens of Example 1 (spherical aberration, astigmatism, distortion aberration; the same applies to FIGS. 3 to 29 (except for FIG. 14)); FIG. 4 is an aberration diagram at a zoom intermediate focus of the zoom lens in Example 1; FIG. 4 is an aberration diagram at a zoom telephoto end of the zoom lens in Example 1; FIG. 6 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 2; 6 is an aberration diagram of a zoom intermediate focus of the zoom lens of Example 2. FIG. FIG. 6 is an aberration diagram at a zoom telephoto end of the zoom lens in Example 2; FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 3; FIG. 10 is an aberration diagram at a zoom intermediate focus of the zoom lens in Example 3; FIG. 10 is an aberration diagram at a zoom telescope end of the zoom lens in Example 3; FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 4; FIG. 10 is an aberration diagram at a zoom intermediate focus of the zoom lens in Example 4; FIG. 10 is an aberration diagram at a zoom telescope end of the zoom lens in Example 4; FIG. 10 is a cross-sectional view illustrating a lens configuration at the time of focusing on infinity at the wide angle end of a zoom lens according to Example 5; FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 5; FIG. 10 is an aberration diagram at a zoom intermediate focus of the zoom lens in Example 5; 10 is an aberration diagram at a zoom telephoto end of the zoom lens in Example 5. FIG. FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 6; 10 is an aberration diagram at a zoom intermediate focus of the zoom lens in Example 6; FIG. 10 is an aberration diagram at a zoom telephoto end of the zoom lens in Example 6; FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 7. FIG. 10 is an aberration diagram of a zoom intermediate focus of the zoom lens in Example 7. FIG. 10 is an aberration diagram at a zoom telescope end of the zoom lens in Example 7. FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 8. FIG. 10 is an aberration diagram at a zoom intermediate focal point of the zoom lens in Example 8; FIG. 10 is an aberration diagram at a zoom telescope end of the zoom lens in Example 8; FIG. FIG. 10 is an aberration diagram at a zoom wide-angle end of the zoom lens in Example 9; 10 is an aberration diagram of a zoom intermediate focus of the zoom lens in Example 9. FIG. 10 is an aberration diagram at a zoom telescope end of the zoom lens in Example 9; FIG. It is a table | surface showing the numerical value of each conditional expression of Example 1- Example 9.

  Embodiments of the zoom lens according to the present invention will be described below. FIG. 1 shows a configuration example of an optical system 100 of a zoom lens according to the present invention. In FIG. 1, as a lens group constituting the optical system 100, 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, and a positive refraction. A third lens group G3 having a power and a fourth lens group G4 having a positive refractive power, and all the lens groups constituting the optical system 100 are adjusted along the optical axis direction so as to adjust the distance between them. And a zoom lens that achieves a predetermined zoom ratio by moving the lens.

1. Configuration Example of Zoom Lens Optical System First, the lens configuration of each lens group constituting the optical system 100 will be described with reference to FIG. However, the optical system of the zoom lens according to the present invention is not limited to the optical system 100 shown in FIG. 1, and includes the first lens group G1 to the fourth lens group G4, and conditional expression (1), which will be described later, As long as various conditional expressions such as conditional expression (2) are satisfied, the number of lens groups and the specific lens configuration are not particularly limited. For example, the optical system of the zoom lens according to the present invention includes other lenses such as a fifth lens group and a sixth lens group following the fourth lens group G4 in addition to the first lens group G1 to the fourth lens group G4. It is good also as a structure provided with a group, and it is good also as what is provided with a fixed lens or a fixed lens group in the most image side among lens groups which constitute the optical system as mentioned below, and the range which does not deviate from the meaning of the present invention In FIG.

  First, the first lens group G1 will be described. In this invention, the 1st lens group G1 should just have positive refractive power as a whole, and the specific lens structure is not specifically limited. For example, as shown in FIG. 1, the first lens group G1 is composed of three lenses in order from the object side: a negative lens 11 having a convex surface on the object side, a positive lens 12 and a positive lens 13 having a convex surface on the object side. can do. Here, as shown in FIG. 1, the negative lens 11 and the positive lens 12 can be cemented lenses. Further, in addition to the three lenses, a positive lens may be further arranged closest to the image side. However, from the viewpoint of reducing the size and cost of the zoom lens, the number of lenses constituting the first lens group G1 should be the minimum number of lenses that can achieve the required optical performance. Of course it is good. The same applies to the other lens groups.

  The second lens group G2 has, in order from the object side, a negative lens 21, a negative lens 22, a positive lens 23, and a negative lens 24 having a convex surface on the object side, and has a negative refractive power as a whole. A specific lens configuration is not particularly limited. For example, as shown in FIG. 1, the second lens group G2 includes a negative meniscus lens 21 having a convex surface on the object side, which is arranged in order from the object side, and a negative meniscus lens 21 arranged next to the negative meniscus lens 21. The lens 22 may include a positive lens 23 having convex surfaces on both sides, a positive lens 23 having convex surfaces on the image surface side, and a negative lens 24 having a concave surface on the object side. In the optical system 100 illustrated in FIG. 1, the second lens group G2 functions as a focus lens, and the second lens group G2 moves toward the object side from the infinite object distance to the close distance during focusing. To perform focusing.

  From the viewpoint of reducing the cost and weight of the optical system 100, the second lens group G2 preferably includes a resin lens. From the standpoint of maintaining good imaging performance and making the zoom lens compact, it is particularly preferable that the negative lens 22 disposed next to the negative meniscus lens 21 is a resin lens.

  The third lens group G3 includes a 3a group having a positive refractive power and a 3b group having a negative refractive power. The 3a group includes a biconvex positive lens 31, a biconvex positive lens 32, and a negative lens 33 in order from the object side. In the example shown in FIG. 1, the negative lens 33 has a concave surface on the object side. For the biconvex positive lens 32 disposed second from the object side, it is more preferable that the radius of curvature of the object side surface is smaller than the radius of curvature of the image side surface. The third lens group is a portion that exhibits a relatively strong positive refracting action, particularly at the wide-angle end, and has a role of correcting over spherical aberration generated in the second lens group to the under side. At this time, by making the curvature radius of the object side surface of the positive lens 32 smaller than the curvature radius of the image side surface, overcorrection to the under side can be suppressed. Further, by reducing the radius of curvature of the object-side surface, a wide air space is provided between the positive lens 31 and the positive lens 32 that are disposed closest to the object side, and the positive lens 32 and the negative meniscus lens 33 are further separated. By making the refractive power of the air lens between them appropriate, spherical aberration can be corrected more favorably, and imaging performance can be further improved not only at the wide angle end but also in the entire zoom range. Further, in the group 3a, another positive lens may be inserted between the biconvex positive lens 31 arranged closest to the object side and the biconvex positive lens 32 arranged next. The specific configuration of the 3a group can be appropriately changed according to the configuration of the 3b group, the configuration of other lens groups, and the like.

  As long as the group 3b has negative refractive power as a whole as shown in FIG. 1, the specific lens configuration is not particularly limited. For example, as shown in FIG. 1, it can be composed of a cemented lens in which a negative lens 34 having a concave surface on both sides and a positive meniscus lens 35 having a convex surface on the object side are cemented. It is also preferable to provide an aspherical layer 36 made of a synthetic resin material on the object side surface of the cemented lens, that is, the object side concave surface of the negative lens 34. In the zoom lens, the 3b group functions as an anti-vibration lens group, and moves in a direction substantially perpendicular to the optical axis during the anti-vibration operation. Therefore, a moving mechanism for moving the group 3b in a direction substantially perpendicular to the optical axis is incorporated in the lens barrel. Since the 3a group has the above-described configuration, the height of the light beam emitted from the 3a group of the Fno light beam (light beam condensing on the optical axis, which is in contact with the diaphragm) can be reduced particularly at the telephoto end. The 3b group can be configured with a small lens. For this reason, even when a moving mechanism for moving the 3b group in a direction substantially perpendicular to the optical axis is incorporated in the lens barrel, it is possible to suppress an increase in the diameter of the lens barrel. Further, by employing a cemented lens, the assembly accuracy of the 3b group can be improved as compared with the case where each lens is separated. In addition, by adopting a cemented lens, the edge shape of the positive meniscus lens 35 can be reduced, so that the vibration-proof lens group (3b) can be reduced in weight. For this reason, it is possible to reduce the load on the anti-vibration actuator that moves the anti-vibration lens group (3b), and it is possible to satisfactorily perform the stopping operation of the anti-vibration lens group (3b).

  Next, the fourth lens group G4 will be described. In the present invention, the fourth lens group G4 has a positive refractive power as a whole, and includes at least three lenses: a biconvex positive lens (42), a biconcave negative lens (43), and a biconvex positive lens (44). The specific lens configuration is not particularly limited. The order of the three lenses is not limited to the example shown in FIG. 1, but the biconvex positive lens 42, the biconcave negative lens 43, and the biconvex positive lens 44 are arranged in this order from the object side. It is preferable. In this case, the lens diameter of the final ball can be reduced by the negative lens 43 between the two positive lenses 42 and 44. In the fourth lens group G4, these three lenses may be arranged in the order of a biconvex positive lens, a biconvex positive lens, and a biconcave negative lens. In this case as well, the lens diameter of the final ball can be reduced, but the back focus is shortened and the incident angle of the light beam on the imaging surface at the most peripheral image height becomes steep, making it difficult to secure the peripheral light amount. Become. Therefore, it is more preferable to arrange these lenses (42, 43, 44) in the order shown in FIG. Note that it is not preferable to arrange these three lenses in the order of a biconcave negative lens, a biconvex positive lens, and a biconvex positive lens because aberration correction becomes difficult.

  In the present invention, the fourth lens group G4 includes, in addition to these three lenses (42, 43, 44), an aspheric lens 41 having a weak refractive power on the most object side of the fourth lens group G4. It is preferable to have. In this case, it is preferable that the aspheric lens is a resin lens, and it is more preferable that each of the object side surface and the image side surface is an aspheric surface. By adopting an aspheric lens, it is possible to satisfactorily correct distortion and the like with a small number of lenses, which is preferable in achieving compactness of the zoom lens. Further, by employing a resin lens, the cost required for the optical system 100 can be reduced as compared with a lens made of glass.

  In the zoom lens according to the present invention, as shown in FIG. 1, the lens group constituting the optical system 100 includes at least four lens groups of the first lens group G1 to the fourth lens group G4, and the first lens group G1 is positive. This is a positive-group-first type zoom lens having a refractive power of 5 mm. In this way, by using the positive lens group type zoom lens, it is possible to realize high imaging performance in a high-magnification zoom lens. Further, by moving all the lens groups constituting the optical system 100 at the time of zooming, it is possible to efficiently secure a zoom zoom ratio with a high magnification and to shorten the optical total length.

  Here, in the zoom lens according to the present invention, during zooming, the distance between the first lens group G1 and the second lens group G2 increases from the wide-angle end to the telephoto end, and the second lens group G2 and the third lens group G3. These lens groups are preferably moved so that the distance between the third lens group G3 and the fourth lens group G4 is narrowed. By moving each lens group in this way, a high zoom ratio can be achieved with a small amount of movement. That is, a zoom lens having a high magnification exceeding 10 times can be configured compactly, and various aberrations can be corrected favorably.

  However, when the 3a group and the 3b group constituting the third lens group G3 are moved together at the time of zooming, the third lens group G3 moves as described above. When the 3a group and the 3b group move independently independently at the time of zooming, the distance between the second lens group G2 and the 3a group is narrowed, and the distance between the 3a group and the 3b group is changed, and the 3b group And the fourth lens group G4 move so that each lens group is narrowed. When the optical system 100 of the zoom lens includes a fifth lens group that moves independently of these lens groups in addition to the first lens group G1 to the fourth lens group G4 shown in FIG. Each lens group so that the distance between G2 and the third lens group G3 is narrowed, the distance between the third lens group G3 and the fourth lens group G4 is narrowed, and the distance between the fourth lens group G4 and the fifth lens group is widened. Move. In the present embodiment, an example in which the third lens group G3 includes the 3a group and the 3b group has been described. However, when these lens groups move independently at the time of zooming, Of course, the 3a group may be referred to as a third lens group, the 3b group may be referred to as a fourth lens group, and the fourth lens group G4 may be referred to as a fifth lens group. In this case, when the fifth lens group (G5) subsequent to the fourth lens group G4 is provided, the fifth lens group (G5) may be referred to as a sixth lens group.

  Further, as described above, among the lens groups constituting the optical system 100 of the zoom lens according to the present invention, other than the first lens group G1 to the fourth lens group G4 described above, the optical system 100 is fixed to the most image side. A lens or a fixed lens group may be arranged. For example, a positive or negative fixed lens or a fixed lens group having a weak refractive power can be arranged. Even if such a fixed lens or a fixed lens group is arranged on the most image side of the optical system 100, the advantage of the zoom lens according to the present invention is not impaired.

2. Conditional expression (1) to conditional expression (8)
In the present invention, the optical system is not simply constructed by using an inexpensive glass lens having a low refractive index to reduce the cost, but the optical system 100 is adopted, and the following conditional expressions (1) to (1): By satisfying (4), etc., it has become possible to simultaneously realize a reduction in cost and compactness of the zoom lens while maintaining high-quality imaging performance. In particular, by satisfying the following conditional expressions (1) to (4), etc., the refractive power distribution in the optical system 100 can be made appropriate, and in particular, the refractive power of the air lens is optimal. It was possible to suppress the under curvature of field and to correct various aberrations satisfactorily. Hereinafter, each conditional expression will be described in order.

2-1. Conditional expression (1) to conditional expression (4)
The zoom lens according to the present invention satisfies the following conditional expressions (1) to (4).

2-1-1. Conditional expression (1)
First, conditional expression (1) will be described. Conditional expression (1) defines the refractive power (shape) of the air lens between the positive lens 23 disposed in the second lens group G2 and the negative lens 24 disposed next to the positive lens 23. Conditional expression. By satisfying the range of the conditional expression (1), the negative refractive power of the air lens can be adjusted within an appropriate range, and in particular, spherical aberration at the telephoto end can be improved. Here, when the upper limit value of the conditional expression (1) is exceeded, the negative refractive power of the air lens between the positive lens 23 and the negative lens 24 becomes weak, and especially the spherical aberration at the telephoto end is excessively large. Therefore, it is not preferable. On the other hand, when the value is less than the lower limit value of the conditional expression (1), the negative refractive power of the air lens becomes strong, and the spherical aberration particularly at the telephoto end becomes excessively large.

  From the viewpoint that better imaging performance can be obtained, it is preferable that in the conditional expression (1), 7.2 ≦ | (R21 + R22) / (R21−R22) | ≦ 15.5 is satisfied, and 7.4 More preferably, ≦ | (R21 + R22) / (R21−R22) | ≦ 15.3.

2-1-2. Conditional expression (2)
Next, conditional expression (2) will be described. Conditional expression (2) is an air lens between the second biconvex positive lens 32 arranged from the object side arranged in the third lens group G3 (group 3a) and the negative lens 33 arranged next to it. Is a conditional expression that prescribes the refractive power (shape). By satisfying the range of the conditional expression (2), it is possible to adjust the negative refractive power of the air lens within an appropriate range, and to improve the spherical aberration from the wide angle end to the telephoto end. Can do. Here, when the upper limit value of conditional expression (2) is exceeded, the negative refractive power of the air lens becomes weak, and the spherical aberration becomes excessively large from the wide-angle end to the telephoto end, which is not preferable. Further, when the value is less than the lower limit value of the conditional expression (2), the negative refractive power of the air lens becomes strong, and the spherical aberration becomes excessively large from the wide angle end to the telephoto end.

  From the viewpoint of obtaining better imaging performance, it is more preferable that 1.65 ≦ | (R31 + R32) / (R31−R32) | ≦ 3.5 in conditional expression (2), 1.74. More preferably, ≦ | (R31 + R32) / (R31−R32) | ≦ 3.4.

2-1-3. Conditional expression (3)
Next, conditional expression (3) will be described. Conditional expression (3) indicates that the refractive power of the air lens between the biconcave negative lens 43 disposed in the fourth lens group G4 and the biconvex positive lens 44 adjacent to the image side of the biconcave negative lens 43. It is a conditional expression that defines (shape). By satisfying the conditional expression (3), the negative refractive power of the air lens can be adjusted to an appropriate range, and the spherical aberration can be improved from the intermediate focal length to the telephoto end. . Here, when the upper limit value of conditional expression (3) is exceeded, the negative refractive power of the air lens becomes weak, and the spherical aberration becomes excessively large from the intermediate focal length to the telephoto end. On the other hand, when the value is less than the lower limit value of the conditional expression (3), the negative refractive power of the air lens becomes strong, and the spherical aberration becomes excessively large from the intermediate focal length to the telephoto end.

  From the viewpoint of obtaining better imaging performance, in Conditional Expression (3), 9.5 ≦ | (RL1 + RL2) / (RL1−RL2) | ≦ 41 is more preferable, and 10.4 ≦ | (RL1 + RL2) ) / (RL1-RL2) | ≦ 40 is more preferable.

2-1-4. Conditional expression (4)
Next, conditional expression (4) will be described. Conditional expression (4) is a conditional expression that defines the distance between the two biconvex positive lenses 31 and 32 arranged in the third lens group G3 (group 3a). By satisfying the conditional expression (4), spherical aberration and coma aberration can be corrected in a balanced manner over the entire zoom range. Here, when the upper limit value of conditional expression (4) is exceeded, spherical aberration at the wide-angle end becomes excessively large, which is not preferable. Further, when the value is less than the lower limit value of the conditional expression (4), it is not preferable because not only the spherical aberration is over in the entire zoom range but also the inward coma becomes excessive.

  From the viewpoint of obtaining better imaging performance, 0.015 ≦ D / D3 ≦ 0.25 is preferable, 0.02 ≦ D / D3 ≦ 0.25 is more preferable, and 0.18 More preferably, ≦ D / D3 ≦ 0.24.

2-2. Conditional expression (5)
In the zoom lens according to the present invention, it is preferable that the following conditional expression (5) is satisfied. The conditional expression (5) indicates that the combined focal length of the positive lens 23 arranged in the second lens group G2 and the negative lens 24 arranged next to the positive lens 23, and the focal length of the second lens group G2. Is a conditional expression that prescribes the relationship.

  By satisfying the conditional expression (5), it is possible to satisfactorily correct curvature of field and coma and to obtain higher quality imaging performance. Here, when the upper limit value of conditional expression (5) is exceeded, the field curvature in the tangential direction becomes extremely excessive in a wide angle of view at the wide-angle end, and inward coma at the telephoto end. Is excessively undesirable. Further, when the value is less than the lower limit value of the conditional expression (5), the field curvature in the tangential direction becomes remarkably excessive at the wide angle end, which is not preferable.

  Further, from the viewpoint of obtaining high-quality imaging performance, in the conditional expression (5), it is more preferable that −0.21 ≦ F2 / F2PN ≦ −0.145, and −0.205 ≦ F2 / F2PN ≦ −. More preferably, it is 0.15.

2-3. Conditional expression (6)
In the zoom lens according to the present invention, it is preferable that the following conditional expression (6) is satisfied. Conditional expression (6) indicates that the second biconvex positive lens 32 from the object side arranged in the third lens group G3 (group 3a), and the negative lens arranged next to the biconvex positive lens 32. This is a conditional expression that defines the relationship between the composite focal length of 33 and the focal length of the third lens group 3G.

  By satisfying the conditional expression (6), it is possible to improve spherical aberration and curvature of field in the entire zoom range, and it is possible to maintain higher-quality imaging performance. Here, when the upper limit value of conditional expression (6) is exceeded, the difference between the wide-angle end and the telephoto end of the spherical aberration becomes large, and the field curvature in the tangential direction becomes excessive on the over side in the entire zoom range, which is preferable. Absent. On the other hand, if it is less than the lower limit value of conditional expression (6), the field curvature in the tangential direction will be excessive on the over side in the entire zoom range, and inward coma will be excessive.

  Further, from the viewpoint of obtaining high-quality imaging performance, in conditional expression (6), it is preferable that 0.13 ≦ F3 / F3PN ≦ 0.4, and 0.14 ≦ F3 / F3PN ≦ 0.3. More preferably.

2-4. Conditional expression (7)
In the zoom lens according to the present invention, it is preferable that the following conditional expression (7) is satisfied. Conditional expression (7) indicates that the combined focal length of the biconcave negative lens 43 arranged in the fourth lens group G4 and the biconvex positive lens 44 adjacent to the image side of the biconcave negative lens 43 is calculated as follows: It is a conditional expression that defines the relationship with the focal length of the lens group G4.

  By satisfying the conditional expression (7), spherical aberration and curvature of field can be improved from the intermediate focal length to the telephoto end. Here, if the upper limit value of conditional expression (7) is exceeded, the spherical aberration becomes excessive on the over side from the intermediate focal length to the telephoto end, and the field curvature in the tangential direction becomes excessive on the over side. Absent. Also, when the conditional expression (7) is less than the lower limit, the spherical aberration becomes excessive on the under side from the intermediate focal length to the telephoto end, and the field curvature in the tangential direction becomes excessive on the under side, which is not preferable.

  From the viewpoint of obtaining higher-quality imaging performance, in the conditional expression (7), it is preferable that 1.4 ≦ | FL / FLPN | ≦ 2.2, and 1.5 ≦ | FL / FLPN | ≦ 2 More preferably, it is 0.0.

2-5. Conditional expression (8)
In the zoom lens according to the present invention, it is preferable that the following conditional expression (8) is satisfied. The conditional expression (8) is a conditional expression relating to the amount of movement of the second lens group G2 and the ratio of the zoom ratio of the fourth lens group G4.

  By satisfying the conditional expression (8), the movement amount of the second lens group G2 and the ratio of the zoom ratio of the fourth lens group G4 can be adjusted to an optimum range, and the expansion of the entire length of the lens barrel is suppressed. can do. Here, when the upper limit value of the conditional expression (8) is exceeded, the movement amount of the second lens group G2 increases, or the zoom ratio of the fourth lens group G4 increases, resulting in an increase in the total optical length. . Also, increasing the overall optical length increases the diameter of the front lens. Of the total volume of the lenses constituting the optical system 100, the volume of the lenses constituting the first lens group G1 occupies about half of that, which causes an increase in cost. Therefore, it is difficult to reduce the size and cost of the zoom lens, which is not preferable. When the conditional expression (8) is less than the lower limit, the movement amount of the second lens group G2 becomes small, or the zoom ratio of the fourth lens group G4 becomes small. In this case, the optical total length is short, and it is not preferable because a high zoom ratio of, for example, 10 times or more cannot be secured.

  From the viewpoint of obtaining higher quality imaging performance, 0.8 ≦ M2 / ft × (| βLT / βLw |) ≦ 6.95 is preferable, and 0.9 ≦ M2 / ft × (| βLT / More preferably, βLw |) ≦ 6.895.

  Next, an Example is shown and this invention is demonstrated concretely. However, it goes without saying that the present invention is not limited to the following Examples 1 to 9. In the following first to ninth embodiments, specific numerical examples when the zoom lens according to the present invention is used in a digital single-lens reflex camera will be described.

  First, the zoom lens of Example 1 will be described. The zoom lens of Example 1 has the same lens configuration as the optical system 100 (see FIG. 1) described above. That is, in the zoom lens of Example 1, as a lens group constituting the optical system 100, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side. And a third lens group G3 having a positive refractive power and a fourth lens group G4 having a positive refractive power. As described above, the second lens group G2 is a focus lens group that moves during focusing. Focusing is performed by moving the second lens group G2 toward the object side when focusing from an infinite object distance to a close distance. STOP shown in FIG. 1 indicates an aperture. IMG indicates an image plane. In zooming from the wide-angle end to the telephoto end, each lens unit moves back and forth on the optical axis so as to change the lens interval. The direction of movement of each lens group and the change in the interval between the lens groups are as schematically shown by arrows in FIG.

  The first lens group G1 (surface numbers 1 to 5) includes a cemented lens in which a negative meniscus lens 11 having a convex surface on the object side and a biconvex positive lens 12 are cemented in order from the object side, and a positive lens having a convex surface on the object side. A meniscus lens 13 is provided. The surface number refers to a number assigned in order from the object side to each surface of the lens constituting the optical system 100. Further, one surface number is given to the joint surface.

  The second lens group G2 (surface numbers 6 to 13) includes, in order from the object side, a negative meniscus lens 21 having a convex surface on the object side, a biconcave negative lens 22, a biconvex positive lens 23, and a negative surface having a convex surface on the image side. The meniscus lens 24 is provided. In the second lens group G2, the biconcave negative lens 22 disposed second from the object side is a resin lens, and both surfaces are aspherical double-sided lenses.

  The third lens group G3 (surface numbers 15 to 24) includes a 3a group (surface numbers 15 to 20) and a 3b group (surface numbers 21 to 24). The group 3a includes a biconvex positive lens 31, a biconvex positive lens 32, and a negative meniscus lens 33 in order from the object side. The group 3b (surface numbers 21 to 24) includes a cemented lens of a biconcave lens 34 and a positive meniscus lens 35. An aspherical layer 36 made of a resin material is bonded to the object side surface of the cemented lens. The group 3b functions as an anti-vibration lens group that moves in a direction substantially perpendicular to the optical axis during image stabilization. The amount of movement of the 3b group during image stabilization is 0.087 mm, 0.182 mm, and 0.467 mm at the wide-angle end, intermediate focal length, and telephoto end, respectively, when the correction angle is equivalent to 0.3 °.

  The stop STOP (surface number 14) is arranged between the second lens group G2 and the third lens group G3. The stop STOP moves integrally with the third lens group G3.

  The fourth lens group G4 (surface numbers 25 to 32) includes, in order from the object side, a positive meniscus lens 41 having a weak refractive power, a biconvex positive lens 42, a biconcave negative lens 43, and a biconvex positive lens 44. Yes. The positive meniscus lens 41 disposed on the most object side is a resin lens, and is a double-sided aspheric lens having both aspheric surfaces.

  In the zoom lens, the 3a group and the 3b group constituting the third lens group G3 may be configured to be independently movable at the time of zooming, and the interval between the 3a group and the 3b group may be changed at the zooming time. . In this case, in order to maintain a high zoom ratio, it is preferable to move the zoom lens from the wide angle end to the telephoto end so that the distance between the 3a group and the 3b group becomes narrow. In Example 1, since the resin lenses are arranged in the second lens group and the fourth lens group, respectively, the cost can be further reduced.

  Next, specific numerical data of each lens constituting the optical system 100 of Example 1 are shown in Tables 1 to 3. Table 1 shows surface data of each lens surface. In Table 1, “No” indicates the surface number of the lens surface. “R” indicates the radius of curvature of the lens surface, and “D” indicates the distance to the next lens surface, and indicates the lens thickness or the lens interval. “Nd” represents the refractive index with respect to the d-line, and “ABV” represents the Abbe number. ASPH indicates that the lens surface is aspherical. These are the same in Table 4, Table 7, Table 10, Table 13, Table 16, Table 19, Table 22, and Table 25.

  Table 2 also shows the focal length (F), F number (Fno), half angle of view (W) (°), and the lens interval (D (5), D (13)) where the interval changes with zooming. , D (24) and D (32), which are described in the order of wide-angle end, intermediate focal length, and telephoto end, respectively, in Table 5, Table 8, Table 11, Table 11. The same applies to 14, Table 17, Table 20, Table 23, and Table 26.

Further, Table 3 shows aspheric data on each lens surface. “No.” indicates the surface number of the lens surface. Table 3 shows the conical coefficient K and the aspheric coefficients A4, A6, A8, and A10 of each order when the rotationally symmetric aspheric surface is defined by the following equation for each lens surface. “Ea” means “× 10 ^−a ”. These are the same in Table 6, Table 9, Table 12, Table 15, Table 18, Table 21, Table 24, and Table 27.

x = cy2 / [1+ [1- (1 + K) c2y2] 1/2] + A4y4 + A6y6 + A8y8 + A10y10 + A12y12 ...
(Where c is the curvature (1 / R), y is the height from the optical axis, K is the conic coefficient, A4, A6, A8,... Are the aspheric coefficients of the respective orders.)

1 is a lens configuration diagram at the wide-angle end of Example 1 when focusing at infinity, FIG. 2 is a longitudinal aberration diagram at the wide-angle end, FIG. 3 is a longitudinal aberration diagram at an intermediate focal length, and FIG. 4 is a telephoto end. FIG. In each aberration diagram, the solid line in the spherical aberration diagram indicates the d line, and the broken line indicates the g line. In the astigmatism diagram, S indicates the sagittal direction, and T indicates the tangential direction. The distortion diagram shows the distortion of the d-line. These are the same in the following drawings.
Furthermore, each conditional expression numerical value is described in FIG. All of the embodiments described below including the first embodiment satisfy the conditional expressions (1) to (8). Each conditional expression numerical value is shown in FIG.

(Table 1)
No. RD Nd ABV
1 79.2809 1.2000 1.84666 23.78
2 52.5933 6.6000 1.49700 81.61
3 -614.1709 0.2000
4 51.3606 4.4000 1.51742 52.15
5 174.6119 D (5)
6 170.7500 1.1000 1.83481 42.72
7 12.7102 6.4500
8 ASPH -29.7960 1.0000 1.53103 58.27
9 ASPH 69.1204 0.2000
10 50.9813 4.2000 1.80518 25.46
11 -23.0148 0.4500
12 -19.4291 0.7000 1.77250 49.62
13 -433.4039 D (13)
14 STOP 0.0000 0.9000
15 30.2112 3.5000 1.48749 70.44
16 -37.6753 2.5202
17 22.4251 3.2000 1.48749 70.44
18 -111.3518 0.4700
19 -46.0666 0.8000 1.84666 23.78
20 -1662.1485 1.5101
21 ASPH -45.6126 0.2000 1.51460 49.96
22 -45.1441 0.7000 1.83400 37.34
23 17.4864 3.0000 1.80518 25.46
24 238.2673 D (24)
25 ASPH 38.3664 1.2000 1.53103 58.27
26 ASPH 43.8962 0.2088
27 35.4894 5.4000 1.51680 64.20
28 -21.7154 0.2000
29 -45.1186 0.8000 1.90366 31.31
30 27.7122 0.3300
31 32.9835 4.5000 1.61293 37.00
32 -37.7350 D (32)

(Table 2)
F 18.5367 60.0953 194.9328
Fno 3.6102 5.1533 6.3504
W 39.3985 13.1639 4.1760
D (5) 1.5834 26.0201 47.9967
D (13) 27.0352 11.2267 1.8173
D (24) 8.0484 3.4417 1.7318
D (32) 43.6191 75.7442 97.0219

(Table 3)
No. K A4 A6 A8 A10
8 0.00000E + 00 -1.65721E-05 2.62792E-07 -4.94483E-09 1.96956E-11
9 0.00000E + 00 -5.19679E-05 1.86714E-07 -4.16967E-09 1.29125E-11
21 0.00000E + 00 1.25827E-05 -5.42177E-08 1.41785E-09 -9.76635E-12
25 0.00000E + 00 7.34439E-06 -5.33421E-07 -4.03799E-09 2.33281E-11
26 0.00000E + 00 4.99364E-05 -5.43708E-07 -3.84796E-09 2.68169E-11

  Next, Example 2 will be described. Since the optical system 100 of the zoom lens of the second embodiment has the same lens configuration as that of the first embodiment, only the configuration different from that of the first embodiment will be described here. The amount of movement of the 3b group during image stabilization is 0.079 mm, 0.159 mm, and 0.394 mm at the wide-angle end, intermediate focal length, and telephoto end, respectively, when the correction angle is equivalent to 0.3 °. Also in the present embodiment, the 3a group and the 3b group may be moved independently along the optical axis direction at the time of zooming, and the direction of the movement is preferably the same as in the first embodiment. This also applies to the third and subsequent embodiments.

  Tables 4, 5 and 6 show lens surface data, data on focal lengths, etc., and aspherical data of each lens constituting the optical system 100 of the zoom lens of Example 2. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 5 shows a longitudinal aberration diagram at the wide-angle end of Example 2, FIG. 6 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 7 shows a longitudinal aberration diagram at the telephoto end.

(Table 4)
No. RD Nd ABV
1 85.6769 1.2000 1.84666 23.78
2 54.5491 6.6000 1.49700 81.61
3 -744.1960 0.2000
4 51.0812 4.4000 1.51742 52.15
5 211.4159 D (5)
6 116.4863 1.1000 1.83481 42.72
7 12.9553 6.4500
8 ASPH -30.6216 1.0000 1.53500 55.73
9 ASPH 43.1756 0.2000
10 36.8962 4.2000 1.80518 25.46
11 -24.1585 0.4500
12 -18.9815 0.7000 1.77250 49.62
13 -2518.8300 D (13)
14 STOP 0.0000 0.9000
15 44.4322 3.5000 1.48749 70.44
16 -27.9130 2.0548
17 24.4675 3.2000 1.48749 70.44
18 -72.5666 0.6314
19 -39.6143 0.8000 1.84666 23.78
20 -254.6992 1.8960
21 ASPH -42.9576 0.2000 1.51460 49.96
22 -44.5492 0.7000 1.83400 37.34
23 16.8661 3.0000 1.80518 25.46
24 152.9125 D (24)
25 ASPH 27.6365 2.0000 1.53500 55.73
26 ASPH 36.8612 0.4000
27 33.0498 5.4000 1.51680 64.20
28 -23.9442 0.2000
29 -123.2342 0.8000 1.90366 31.31
30 21.0304 0.5096
31 24.4600 4.5000 1.61293 37.00
32 -69.0950 D (32)

(Table 5)
F 18.5399 60.1820 194.9318
Fno 3.4035 5.1410 6.7162
W 39.6098 13.2190 4.1803
D (5) 1.5820 24.7478 47.5001
D (13) 25.1338 10.4459 1.8808
D (24) 9.8417 2.8601 1.2014
D (32) 43.2506 76.7171 101.2265

(Table 6)
No. K A4 A6 A8 A10
8 0.00000E + 00 -2.75012E-05 4.52637E-07 -8.42515E-09 7.80026E-11
9 0.00000E + 00 -6.10468E-05 4.76965E-07 -8.79289E-09 7.94088E-11
21 0.00000E + 00 1.29035E-05 -9.09540E-09 1.16929E-10 -4.20437E-13
25 0.00000E + 00 4.74367E-06 -4.86981E-07 -2.70490E-09 2.45037E-12
26 0.00000E + 00 4.34690E-05 -5.05282E-07 -3.68874E-09 1.62240E-11

  Next, Example 3 will be described. Since the optical system 100 of the zoom lens according to the third embodiment has the same lens configuration as that of the first embodiment, only the configuration different from the first embodiment will be described here. Also in the optical system 100 of the third embodiment, among the 3a group and 3b group constituting the third lens group 3G, the 3b group can be moved in a direction substantially perpendicular to the optical axis during image stabilization. The amount of movement of the 3b group during image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group during image stabilization is 0.089 mm, 0.182 mm, respectively at the wide angle end, the intermediate focal length, and the telephoto end. 0.460 mm.

  Tables 7, 8, and 9 show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 3. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 8 shows a longitudinal aberration diagram at the wide-angle end of Example 3, FIG. 9 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 10 shows a longitudinal aberration diagram at the telephoto end.

(Table 7)
No. RD Nd ABV
1 93.7711 1.2000 1.84666 23.78
2 58.2256 6.6000 1.49700 81.61
3 -464.8530 0.2000
4 48.7486 4.4000 1.51742 52.15
5 191.5000 D (5)
6 191.5000 1.1000 1.83481 42.72
7 13.5213 6.4500
8 ASPH -26.2868 1.0000 1.53500 55.73
9 ASPH 66.1801 0.2000
10 54.6432 4.2000 1.80518 25.46
11 -22.6225 0.4500
12 -19.2728 0.7000 1.77250 49.62
13 -238.9571 D (13)
14 STOP 0.0000 0.9000
15 31.9118 3.5000 1.48749 70.44
16 -34.5240 2.4976
17 22.7369 3.2000 1.48749 70.44
18 -114.8993 0.5000
19 -48.0417 0.8000 1.84666 23.78
20 1354.5969 1.5068
21 ASPH -42.8017 0.2000 1.51460 49.96
22 -41.7755 0.7000 1.83400 37.34
23 18.1218 3.0000 1.80518 25.46
24 511.6480 D (24)
25 ASPH 34.9797 1.2000 1.53500 55.73
26 ASPH 60.6849 0.4000
27 45.8144 5.4000 1.51680 64.20
28 -22.7514 0.2000
29 -50.7204 0.8000 1.90366 31.31
30 25.4079 0.3000
31 29.9097 4.5000 1.61293 37.00
32 -42.6319 D (32)

(Table 8)
F 18.5400 60.1123 194.9318
Fno 3.6232 5.2074 6.3201
W 39.6086 13.2574 4.1751
D (5) 1.5679 24.5305 47.0537
D (13) 27.3496 11.1325 1.9807
D (24) 9.1029 3.0915 1.2021
D (32) 42.8085 76.7843 99.7054

(Table 9)
No. K A4 A6 A8 A10
8 0.00000E + 00 -1.57783E-05 3.47553E-07 -4.49279E-09 3.46545E-11
9 0.00000E + 00 -4.37479E-05 2.09462E-07 -2.47794E-09 2.17697E-11
21 0.00000E + 00 1.12892E-05 -2.03616E-08 1.39390E-10 -7.50392E-13
25 0.00000E + 00 1.06310E-05 -5.00666E-07 -3.57362E-09 2.31277E-11
26 0.00000E + 00 4.90997E-05 -4.91326E-07 -4.07391E-09 2.72747E-11

  Next, Example 4 will be described. Since the optical system 100 of the zoom lens of Example 4 has the same lens configuration as that of Example 1, only the configuration different from that of Example 1 will be described here. Also in the optical system 100 of Example 4, among the 3a group and 3b group constituting the third lens group 3G, the 3b group can be moved in a direction substantially perpendicular to the optical axis at the time of image stabilization. The amount of movement of the 3b group at the time of image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group at the time of image stabilization is 0.081 mm and 0.162 mm at the wide angle end, the intermediate focal length, and the telephoto end, respectively. 0.393 mm.

  Tables 10, 11, and 12 show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 4. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 11 shows a longitudinal aberration diagram at the wide-angle end of Example 4, FIG. 12 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 13 shows a longitudinal aberration diagram at the telephoto end.

(Table 10)
No. RD Nd ABV
1 88.0801 1.2000 1.84666 23.78
2 55.9799 6.6000 1.49700 81.61
3 -431.9951 0.2000
4 45.8200 4.4000 1.51742 52.15
5 138.4889 D (5)
6 138.4889 1.1000 1.83481 42.72
7 12.3978 6.4500
8 ASPH -29.2630 1.0000 1.53500 55.73
9 ASPH 71.6506 0.2000
10 51.6418 4.2000 1.80518 25.46
11 -21.4449 0.4500
12 -18.1107 0.7000 1.77250 49.62
13 -303.8809 D (13)
14 STOP 0.0000 0.9000
15 36.6598 3.5000 1.48749 70.44
16 -29.8614 1.3985
17 28.1558 3.2000 1.48749 70.44
18 -58.2841 0.7317
19 -31.5585 0.8000 1.84666 23.78
20 -103.7276 2.3698
21 ASPH -43.6536 0.2000 1.51460 49.96
22 -43.6738 0.7000 1.83400 37.34
23 17.6417 3.0000 1.80518 25.46
24 170.6483 D (24)
25 ASPH 31.1605 2.3000 1.53500 55.73
26 ASPH 45.3590 0.4000
27 35.8419 5.5000 1.51930 76.22
28 -23.3447 0.2000
29 -480.4811 0.8000 1.90366 31.31
30 18.1214 0.3000
31 19.7882 4.8000 1.61480 32.56
32 -180.8215 D (32)

(Table 11)
F 18.4970 60.2102 195.9352
Fno 3.5342 5.3023 6.8236
W 39.2789 13.2492 4.1705
D (5) 1.7482 24.1104 45.6682
D (13) 25.7562 10.6900 1.9961
D (24) 9.8770 3.1260 1.2000
D (32) 41.9380 75.4677 102.4553

(Table 12)
No. K A4 A6 A8 A10
8 0.00000E + 00 -3.66039E-05 4.12050E-07 -6.60380E-09 3.92860E-11
9 0.00000E + 00 -7.05425E-05 2.58798E-07 -4.61122E-09 2.34229E-11
21 0.00000E + 00 1.29486E-05 -3.36487E-08 6.70755E-10 -3.87383E-12
25 0.00000E + 00 4.70142E-07 -3.13787E-07 -2.62551E-09 3.88171E-12
26 0.00000E + 00 3.50386E-05 -2.80506E-07 -3.39213E-09 1.24497E-11

  Next, Example 5 will be described. As shown in FIG. 14, the optical system 100 of the zoom lens according to the fifth embodiment has a configuration in which a meniscus lens 41 ′ having a convex surface on the image side and having a weak refractive power is disposed on the most object side of the fourth lens group G4. The lens configuration is the same as in Example 1. In Example 5, the amount of movement of the 3b group at the time of image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group at the time of image stabilization is 0.098 mm at the wide angle end, the intermediate focal length, and the telephoto end, respectively. , 0.197 mm and 0.510 mm. FIG. 14 is a lens configuration diagram of Example 5 when focusing on infinity at the wide angle end.

  Tables 13, 14, and 15 show lens surface data, data on focal lengths, and the like of each lens constituting the optical system 100 of the zoom lens of Example 5 and aspherical data, respectively. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 15 shows a longitudinal aberration diagram at the wide-angle end of Example 5, FIG. 16 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 17 shows a longitudinal aberration diagram at the telephoto end.

(Table 13)
No. RD Nd ABV
1 74.0291 1.2000 1.84666 23.78
2 53.6702 6.6000 1.49700 81.61
3 -880.7764 0.2000
4 47.4349 4.4000 1.48749 70.44
5 126.0382 D (5)
6 126.0353 1.1000 1.83481 42.72
7 11.6751 6.4500
8 ASPH -27.2784 1.0000 1.53500 55.73
9 ASPH 150.5665 0.2000
10 43.6483 4.2000 1.80518 25.46
11 -24.9815 0.4500
12 -19.0886 0.7000 1.77250 49.62
13 -411.2679 D (13)
14 STOP 0.0000 0.9000
15 34.9398 3.5000 1.48749 70.44
16 -27.1815 0.2185
17 27.3115 3.2000 1.48749 70.44
18 -93.9694 0.9668
19 -31.4642 0.8000 1.84666 23.78
20 -88.6949 3.8789
21 ASPH -52.6283 0.2000 1.51460 49.96
22 -51.6218 0.7000 1.83400 37.34
23 16.0407 3.0000 1.80518 25.46
24 228.8638 D (24)
25 ASPH -12.3995 1.2000 1.53500 55.73
26 ASPH -12.3995 0.2000
27 26.4553 5.4000 1.51680 64.20
28 -25.2336 0.2000
29 -49.0656 0.8000 1.90366 31.31
30 22.6243 0.4001
31 25.1684 4.5000 1.61293 37.00
32 -53.4100 D (32)

(Table 14)
F 18.5399 60.1478 194.9318
Fno 3.5898 5.2679 6.3744
W 39.4748 13.3124 4.1826
D (5) 1.5998 24.2857 47.2777
D (13) 27.0168 10.7671 1.8819
D (24) 11.7340 4.2659 3.7314
D (32) 40.0850 76.5138 99.5450

(Table 15)
No. K A4 A6 A8 A10
8 0.00000E + 00 -7.34584E-06 6.12996E-07 -1.13798E-08 5.81423E-11
9 0.00000E + 00 -4.81863E-05 3.60598E-07 -8.77067E-09 3.50301E-11
21 0.00000E + 00 8.64198E-06 4.21651E-08 2.21659E-11 -2.88242E-12
25 0.00000E + 00 4.37665E-06 2.30202E-06 7.33710E-09 -6.17645E-11
26 0.00000E + 00 3.38361E-05 1.91937E-06 8.30436E-09 -4.54006E-11

  Next, Example 6 will be described. Since the zoom lens optical system 100 according to the sixth embodiment has the same lens configuration as that of the first embodiment, only the configuration different from that of the first embodiment will be described. Also in the optical system 100 of Example 6, among the 3a group and 3b group constituting the third lens group 3G, the 3b group can be moved in a direction substantially perpendicular to the optical axis during image stabilization. The amount of movement of the 3b group during image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group during image stabilization is 0.099 mm, 0.195 mm, respectively at the wide angle end, the intermediate focal length, and the telephoto end 0.505 mm.

  Table 16, Table 17, and Table 18 show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 6. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 18 shows a longitudinal aberration diagram at the wide-angle end of Example 6, FIG. 19 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 20 shows a longitudinal aberration diagram at the telephoto end.

(Table 16)
No. RD Nd ABV
1 72.9234 1.2000 1.84666 23.78
2 46.4791 6.6000 1.48749 70.44
3 -417.8784 0.2000
4 70.9880 4.4000 1.59551 39.22
5 278.6753 D (5)
6 278.6753 1.1000 1.83481 42.72
7 14.6372 6.4500
8 ASPH -26.5101 1.0000 1.53500 55.73
9 ASPH 48.1439 0.2000
10 61.7992 4.2000 1.80518 25.46
11 -24.3665 0.4500
12 -21.3765 0.7000 1.77250 49.62
13 -175.3295 D (13)
14 STOP 0.0000 0.9000
15 32.6012 3.5000 1.51823 58.96
16 -35.1785 0.1500
17 26.4069 3.2000 1.51823 58.96
18 -106.0549 0.5000
19 -46.9670 0.8000 1.84666 23.78
20 1187.1848 3.8505
21 ASPH -47.3498 0.2000 1.51460 49.96
22 -45.9055 0.7000 1.83400 37.34
23 21.4907 3.0000 1.80518 25.46
24 451.5217 D (24)
25 ASPH 37.0000 1.2000 1.53500 55.73
26 ASPH 40.7491 0.4000
27 39.6153 5.4000 1.51680 64.20
28 -20.6521 0.2000
29 -44.2668 0.8000 1.90366 31.31
30 27.7632 0.3000
31 29.2040 4.5000 1.61293 37.00
32 -44.4225 D (32)

(Table 17)
F 18.5400 60.0650 194.9318
Fno 3.6232 5.2074 6.3201
W 39.5658 13.1537 4.1751
D (5) 1.5456 23.7125 49.9865
D (13) 27.3287 10.2295 1.8827
D (24) 11.4139 3.3853 1.2000
D (32) 40.6110 78.6522 99.8302

(Table 18)
No. K A4 A6 A8 A10
8 0.00000E + 00 -7.03354E-06 -4.42659E-07 2.74935E-09 4.43087E-12
9 0.00000E + 00 -4.08021E-05 -2.80851E-07 1.61432E-09 1.22777E-11
21 0.00000E + 00 1.74968E-05 -3.50285E-07 4.36919E-09 -1.76130E-11
25 0.00000E + 00 -1.36106E-05 -1.70783E-07 -6.08880E-09 2.59240E-11
26 0.00000E + 00 3.63745E-05 -3.85643E-07 -3.57530E-09 2.04368E-11

  Next, Example 7 will be described. In the zoom lens optical system 100 according to the seventh embodiment, similarly to the fifth embodiment, a meniscus lens 41 ′ having a convex surface on the image side and having a weak refractive power is disposed on the most object side of the fourth lens group G4. The lens configuration is the same as in Example 1 (see FIG. 14). The amount of movement of the 3b group at the time of image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group at the time of image stabilization is 0.093 mm, 0.190 mm at the wide angle end, the intermediate focal length, and the telephoto end, respectively. 0.503 mm.

  Table 19, Table 20, and Table 21 show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 7. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 21 shows a longitudinal aberration diagram of Example 7 at the wide-angle end, FIG. 22 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 23 shows a longitudinal aberration diagram at the telephoto end.

(Table 19)
No. RD Nd ABV
1 80.1795 1.2000 1.84666 23.78
2 52.5830 6.6000 1.49700 81.61
3 -1499.5977 0.2000
4 48.7939 4.4000 1.51742 52.15
5 182.4637 D (5)
6 127.7312 1.1000 1.83481 42.72
7 11.4033 6.4500
8 ASPH -22.1263 1.0000 1.53500 55.73
9 ASPH -170.8187 0.2000
10 64.2619 4.2000 1.80518 25.46
11 -21.2327 0.4500
12 -17.4462 0.7000 1.77250 49.62
13 -153.0147 D (13)
14 STOP 0.0000 0.9000
15 32.5759 3.5000 1.48749 70.44
16 -28.1520 1.6769
17 26.5013 3.2000 1.48749 70.44
18 -110.0391 0.8000
19 -29.8141 0.8000 1.84666 23.78
20 -84.1143 2.1667
21 ASPH -48.5225 0.2000 1.51460 49.96
22 -47.1299 0.7000 1.83400 37.34
23 18.0639 3.0000 1.80518 25.46
24 292.4861 D (24)
25 ASPH 68.8155 1.2000 1.53500 55.73
26 ASPH 77.8852 0.4000
27 42.6551 5.6000 1.51680 64.20
28 -19.2945 0.2000
29 -38.8321 0.8000 1.90366 31.31
30 29.2522 0.3000
31 34.4536 4.5000 1.61293 37.00
32 -35.4954 D (32)

(Table 20)
F 18.5400 60.0868 194.9318
Fno 3.6232 5.2074 6.3201
W 39.4719 13.2649 4.1752
D (5) 1.6639 25.2764 48.3682
D (13) 26.7932 11.0434 1.8023
D (24) 8.4816 1.7184 1.3072
D (32) 43.4589 77.6727 97.8548

(Table 21)
No. K A4 A6 A8 A10
8 0.00000E + 00 2.45035E-05 -6.52477E-08 -9.02104E-09 3.86589E-11
9 0.00000E + 00 -2.63639E-05 -2.98791E-07 -6.77767E-09 2.49265E-11
21 0.00000E + 00 1.11942E-05 -2.16091E-08 5.76059E-10 -3.65561E-12
25 0.00000E + 00 3.49150E-05 -4.55109E-07 -5.45488E-09 2.51667E-11
26 0.00000E + 00 7.39117E-05 -4.05991E-07 -5.74949E-09 3.15973E-11

  Next, Example 8 will be described. Since the optical system 100 of the zoom lens of the eighth embodiment has the same lens configuration as that of the first embodiment, only the configuration different from that of the first embodiment will be described here. In the optical system 100 of Example 8, the 3a group and the 3b group constituting the third lens group are independent along the optical axis direction so that the air space between the wide angle end and the telephoto end becomes narrower at the time of zooming. Move to. The amount of movement of the 3b group at the time of image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group at the time of image stabilization is 0.089 mm, 0.181 mm at the wide angle end, the intermediate focal length, and the telephoto end, respectively. 0.474 mm.

  Table 22, Table 23, and Table 24 show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 8. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 24 shows a longitudinal aberration diagram of Example 8 at the wide-angle end, FIG. 25 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 26 shows a longitudinal aberration diagram at the telephoto end.

(Table 22)
No. RD Nd ABV
1 78.7433 1.2000 1.84666 23.78
2 52.6992 6.7000 1.49700 81.61
3 -667.7771 0.2000
4 52.6948 4.4000 1.51742 52.15
5 176.8095 D (5)
6 171.4263 1.2000 1.83481 42.72
7 12.4677 6.3809
8 ASPH -30.1202 1.0000 1.53110 58.60
9 ASPH 74.4645 0.2000
10 50.1721 4.4000 1.80518 25.46
11 -23.5391 0.4600
12 -19.6638 0.7000 1.77250 49.62
13 -268.9056 D (13)
14 STOP 0.0000 0.9000
15 29.3794 3.6000 1.48749 70.44
16 -37.4302 1.6270
17 23.8446 3.7000 1.48749 70.44
18 -89.4371 0.4000
19 -42.6556 0.8000 1.84666 23.78
20 -512.7271 D (20)
21 ASPH -46.7691 0.2000 1.51460 49.96
22 -46.9730 0.8000 1.83400 37.34
23 17.0833 3.1000 1.80518 25.46
24 212.5403 D (24)
25 ASPH 48.5158 1.2000 1.53110 58.60
26 ASPH 58.0346 0.1500
27 33.7204 5.6000 1.51680 64.20
28 -22.3278 0.1560
29 -46.1490 0.8000 1.90366 31.31
30 26.2451 0.3800
31 31.8064 4.5000 1.61293 37.00
32 -37.8637 D (32)

(Table 23)
F 18.5400 60.1100 194.9329
Fno 3.6649 5.3376 6.4466
W 39.0745 13.1688 4.1752
D (5) 1.5138 25.1995 48.8656
D (13) 27.6423 11.1430 1.8088
D (20) 2.7248 2.5603 1.7730
D (24) 7.8979 2.8172 1.3800
D (32) 41.4174 75.4358 95.4506

(Table 24)
No. K A4 A6 A8 A10
8 0.00000E + 00 -1.14769E-05 4.70839E-08 -2.63504E-09 1.24054E-11
9 0.00000E + 00 -4.98347E-05 -4.49970E-08 -1.88618E-09 6.45086E-12
21 0.00000E + 00 1.19796E-05 -2.92430E-08 9.47719E-10 -7.32654E-12
25 0.00000E + 00 -1.07090E-05 -4.72810E-07 -2.76695E-09 2.07109E-11
26 0.00000E + 00 2.99368E-05 -4.59231E-07 -2.41715E-09 2.15679E-11

  Next, Example 9 will be described. Since the zoom lens optical system 100 according to the ninth embodiment has the same lens configuration as that of the first embodiment, only the configuration different from that of the first embodiment will be described. In the optical system 100 of Example 9, the 3a group and the 3b group constituting the third lens group move independently along the optical axis direction so that the air gap between them becomes narrow at the time of zooming. Also in the optical system 100, among the 3a group and 3b group constituting the third lens group 3G, the 3b group can be moved in a direction substantially perpendicular to the optical axis during image stabilization. The amount of movement of the 3b group at the time of image stabilization is equivalent to a correction angle of 0.3 °, and the amount of movement of the 3b group at the time of image stabilization is 0.089 mm, 0.181 mm at the wide angle end, the intermediate focal length, and the telephoto end, respectively. 0.474 mm.

  Table 25, Table 26, and Table 27 below show lens surface data, focal length data, and aspheric data of each lens constituting the optical system 100 of the zoom lens of Example 9. Moreover, each conditional expression numerical value is shown in FIG. Further, FIG. 27 shows a longitudinal aberration diagram at the wide-angle end of Example 9, FIG. 28 shows a longitudinal aberration diagram at the intermediate focal length, and FIG. 29 shows a longitudinal aberration diagram at the telephoto end.

(Table 25)
No. RD Nd ABV
1 81.0662 1.2000 1.84666 23.78
2 53.5297 6.6000 1.49700 81.61
3 -814.2792 0.2000
4 52.2329 4.4000 1.51742 52.15
5 195.9920 D (5)
6 195.9920 1.1000 1.83481 42.72
7 12.8669 6.4500
8 ASPH -26.6048 1.0000 1.53103 58.27
9 ASPH 98.2891 0.2000
10 50.8434 4.4000 1.80518 25.46
11 -23.3493 0.4600
12 -19.0740 0.7000 1.77250 49.62
13 -230.6555 D (13)
14 STOP 0.0000 0.9000
15 32.4971 3.6000 1.48749 70.44
16 -34.7066 1.9500
17 23.1922 3.6000 1.48749 70.44
18 -89.2603 0.4500
19 -42.0273 0.8000 1.84666 23.78
20 -467.3151 D (20)
21 ASPH -47.8795 0.2000 1.51460 49.96
22 -48.3845 0.7000 1.83400 37.34
23 16.8825 3.0000 1.80518 25.46
24 194.2614 D (24)
25 ASPH 34.3111 1.2000 1.53103 58.27
26 ASPH 37.7297 0.1500
27 37.0491 5.6000 1.51680 64.20
28 -20.7740 0.1600
29 -37.6215 0.8000 1.90366 31.31
30 29.7997 0.3800
31 35.8567 4.5000 1.61293 37.00
32 -32.7692 D (32)

(Table 26)
F 18.5136 60.0681 194.9318
Fno 3.6223 5.2626 6.2969
W 39.6510 13.2226 4.1751
D (5) 1.5962 25.3923 48.9184
D (13) 27.6928 11.2082 1.8013
D (20) 2.8381 2.4372 1.6000
D (24) 8.0972 2.3333 1.2000
D (32) 41.9921 76.3615 96.9967

(Table 27)
No. K A4 A6 A8 A10
8 0.00000E + 00 1.31599E-05 -2.73202E-08 -3.40841E-09 2.47387E-11
9 0.00000E + 00 -2.32801E-05 -1.87538E-07 -1.36401E-09 8.45448E-12
21 0.00000E + 00 1.24302E-05 -5.08935E-08 1.07027E-09 -6.51853E-12
25 0.00000E + 00 1.70166E-05 -6.84744E-07 -3.95111E-09 2.71942E-11
26 0.00000E + 00 6.02044E-05 -7.15308E-07 -3.74756E-09 3.10070E-11

DESCRIPTION OF SYMBOLS 21 ... Negative lens 22 ... Negative lens 23 ... Positive lens 24 ... Negative lens 31 ... Biconvex positive lens 32 ... Biconvex positive lens 33 ... Negative lens 42 ... Biconvex positive lens 43... Biconcave negative lens 44... Biconvex positive lens 100 .. Optical system G1... First lens group G2. Second lens group G3. ..3a group G3b ..3b group G4... Fourth lens group

Claims (11)

As a lens group constituting the optical system, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, A fourth lens group having a positive refractive power,
A zoom lens that achieves a predetermined magnification by moving along the optical axis direction so that all the lens groups constituting the optical system adjust their intervals,
The second lens group includes, in order from the object side, a negative lens having a convex surface on the object side, a negative lens, a positive lens, and a negative lens.
The third lens group includes a 3a group having a positive refractive power and a 3b group having a negative refractive power,
The 3a group includes, in order from the object side, a biconvex positive lens, a biconvex positive lens, and a negative lens.
The 3b group moves in a direction substantially perpendicular to the optical axis during vibration isolation,
The fourth lens group has at least three lenses, a biconvex positive lens, a biconcave negative lens, and a biconvex positive lens,
A zoom lens satisfying the following conditional expressions (1) to (4):

The zoom lens according to claim 1, wherein the following conditional expression (5) is satisfied.

The zoom lens according to claim 1 or 2, wherein the following conditional expression (6) is satisfied.

The zoom lens according to any one of claims 1 to 3, wherein the following conditional expression (7) is satisfied.

The zoom lens according to any one of claims 1 to 4, wherein the following conditional expression (8) is satisfied.

  At the time of zooming, the distance between the first lens group and the second lens group increases from the wide-angle end to the telephoto end, the distance between the second lens group and the third lens group decreases, and the third lens group The zoom lens according to any one of claims 1 to 5, wherein these lens groups move so that a distance between the first lens group and the fourth lens group decreases.   During zooming, the distance between the second lens group and the 3a group decreases from the wide-angle end to the telephoto end, the distance between the 3a group and the 3b group changes, and the 3b group and the fourth lens group The zoom lens according to claim 6, wherein these lens groups are moved so that the distance between them is reduced. As a lens group constituting the optical system, in addition to the fourth lens group from the first lens group, a fifth lens group following the fourth lens group,
At the time of zooming, the distance between the first lens group and the second lens group increases from the wide-angle end to the telephoto end, the distance between the second lens group and the third lens group decreases, and the third lens group And the fourth lens group are narrowed, and the lens groups are moved so that the distance between the fourth lens group and the fifth lens group is widened. Zoom lens described in 1.   The lens group constituting the optical system includes a fixed lens or a fixed lens group closest to the image side in addition to the first lens group to the fourth lens group. The described zoom lens.   The zoom lens according to any one of claims 1 to 9, wherein the second lens group moves toward the object side from an infinite object distance to a close distance during focusing.   The zoom lens according to any one of claims 1 to 10, wherein the second lens group and / or the fourth lens group includes at least one resin lens.

Images