Zoom lens and imaging device

Abstract

To solve the above problem, the zoom lens is characterized by comprising, in order from the object side, a positive first lens group (G1), a negative second lens group (G2), a positive third lens group (G3), a positive fourth lens group (G4), a negative fifth lens group (G5), and a sixth lens group, the interval on the optical axis between adjacent lens groups changes during zooming, and a prescribed conditional expression is satisfied. In addition, the imaging device comprises the zoom lens.

Description

[0001] This application is a divisional application of application number 201811403960.7 filed on November 23, 2018, entitled "Zoom Lens and Camera Device". Technical Field

[0002] This invention relates to zoom lenses and imaging devices, and more particularly to zoom lenses and imaging devices suitable for digital cameras, digital camcorders and other imaging devices that use solid-state imaging elements (CCD, CMOS, etc.). Background Technology

[0003] In the current technological landscape, imaging devices using solid-state imaging elements, such as digital cameras and digital camcorders, are widely used. Examples of such imaging devices include digital cameras, digital camcorders, broadcast / movie cameras, surveillance cameras, and vehicle-mounted cameras. With the increasing integration of the light-receiving elements that constitute solid-state imaging elements, all imaging devices are continuously becoming more functional and miniaturized, requiring further improvements in performance and miniaturization in the imaging optical systems of these devices.

[0004] Zoom lenses have been widely used in camera optical systems. Besides high performance and miniaturization, zoom lenses also require wide-angle and high magnification. For example, Patent Document 1 discloses a zoom lens composed of five lens groups: positive-negative-positive-negative-positive. Patent Document 2 discloses a zoom lens composed of six lens groups: positive-negative-positive-positive-negative-positive. Such so-called positive-leading zoom lenses are easy to achieve high magnification, and offer high freedom of movement in terms of the amount and direction of movement when zooming. Therefore, it is easy to achieve the desired zoom ratio and suppress aberration variations, making it easy to achieve zoom lenses with high optical performance throughout the entire zoom range.

[0005] [Existing Technical Documents]

[0006] [Patent Documents]

[0007] Patent Document 1: Japanese Patent Application Publication No. 8-179213

[0008] Patent Document 2: Japanese Patent Application Publication No. 2017-151240 Summary of the Invention

[0009] However, the zoom lens disclosed in Patent Document 1 has low combined refractive power from the first lens group to the fourth lens group, and the combined focal length is a negative value. In this zoom lens, the half angle of view at the wide-angle end is 41 degrees, achieving wide-angle coverage, but the height of the peripheral light rays passing through the fifth lens group at the wide-angle end is high. Therefore, due to the limitations of the inner diameter of the camera mounting part and the lens mounting part, vignetting of the peripheral beam occurs, making it difficult to ensure abundant peripheral light. In addition, since the diameter of the final lens group, i.e., the fifth lens group, is larger, it is also difficult to achieve radial miniaturization of this zoom lens. Furthermore, the zoom ratio of the zoom lens disclosed in Patent Document 1 is about 4x, and to achieve high zoom, it is necessary to increase the amount of movement of each lens group during zooming. In addition, to achieve good imaging performance, it is necessary to increase the number of constituent lenses used for aberration correction. Thus, if high zoom is to be achieved, the overall optical length increases, making it even more difficult to ensure abundant peripheral light.

[0010] The zoom lens disclosed in Patent Document 2 achieves a high zoom ratio of approximately 12x. However, in this zoom lens, due to the weak combined refractive power from the first lens group to the fifth lens group, the height of the peripheral beam passing through the final lens group, namely the sixth lens group, is high, making it difficult to ensure the amount of peripheral light and to achieve radial miniaturization.

[0011] The objective of this invention is to provide a zoom lens that is rich in peripheral light, has high optical performance, high zoom ratio, and is compact, as well as a camera device having the zoom lens.

[0012] To solve the above-mentioned problems, the zoom lens of the present invention comprises, 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 positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group, and the spacing between adjacent lens groups changes on the optical axis during zooming, characterized in that the following condition is satisfied.

[0013] 0.10≤f34w / |f5|≤0.75……(1)

[0014] -0.5≤fw / f5iw≤0.2……(2)

[0015] in,

[0016] f34w: The combined focal length of the third and fourth lens groups at the wide-angle end;

[0017] f5: The focal length of the fifth lens group;

[0018] fw: The focal length of the zoom lens at the wide-angle end;

[0019] f5iw: The combined focal length from the fifth lens group at the wide-angle end to the lens group located on the image side of the zoom lens.

[0020] In addition, in order to solve the above-mentioned problems, the imaging device of the present invention is characterized by having the zoom lens of the present invention and an imaging element that converts the optical image formed by the zoom lens into an electrical signal on the image side of the zoom lens.

[0021] The beneficial effects of this invention are as follows:

[0022] According to the present invention, a zoom lens with abundant peripheral light, high optical performance, high zoom ratio, and small size, as well as a camera device having the zoom lens, can be provided. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the zoom lens in embodiment 1 of the present invention when focused at infinity at the wide-angle end.

[0024] Figure 2 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 1.

[0025] Figure 3 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 1.

[0026] Figure 4 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 1.

[0027] Figure 5 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 1.

[0028] Figure 6 This is a cross-sectional view of the zoom lens in embodiment 2 of the present invention when focused at infinity at the wide-angle end.

[0029] Figure 7 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the wide-angle end in Example 2.

[0030] Figure 8 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 2.

[0031] Figure 9 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 2.

[0032] Figure 10These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 2.

[0033] Figure 11 This is a cross-sectional view of the zoom lens in embodiment 3 of the present invention when focused at infinity at the wide-angle end.

[0034] Figure 12 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 3.

[0035] Figure 13 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 3.

[0036] Figure 14 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 3.

[0037] Figure 15 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 3.

[0038] Figure 16 This is a cross-sectional view of the zoom lens in embodiment 4 of the present invention when focused at infinity at the wide-angle end.

[0039] Figure 17 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 4.

[0040] Figure 18 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 4.

[0041] Figure 19 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 4.

[0042] Figure 20 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 4.

[0043] Figure 21 This is a cross-sectional view of the zoom lens in embodiment 5 of the present invention when focused at infinity at the wide-angle end.

[0044] Figure 22 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 5.

[0045] Figure 23These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 5.

[0046] Figure 24 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 5.

[0047] Figure 25 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 5.

[0048] Figure 26 This is a cross-sectional view of the zoom lens in embodiment 6 of the present invention when focused at infinity at the wide-angle end.

[0049] Figure 27 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 6.

[0050] Figure 28 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 6.

[0051] Figure 29 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 6.

[0052] Figure 30 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 6.

[0053] Figure 31 This is a cross-sectional view of the zoom lens in embodiment 7 of the present invention when focused at infinity at the wide-angle end.

[0054] Figure 32 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 7.

[0055] Figure 33 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 7.

[0056] Figure 34 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 7.

[0057] Figure 35 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 7.

[0058] Figure 36This is a cross-sectional view of the zoom lens in embodiment 8 of the present invention when focused at infinity at the wide-angle end.

[0059] Figure 37 These are the spherical aberration map, astigmatism map, and distortion aberration map of the wide-angle end when focusing at infinity in Example 8.

[0060] Figure 38 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the first intermediate focal length position in Example 8.

[0061] Figure 39 These are the spherical aberration map, astigmatism map, and distortion aberration map when focusing at infinity at the second intermediate focal length position in Example 8.

[0062] Figure 40 These are the spherical aberration map, astigmatism map, and distortion aberration map of the telescope at infinity focusing in Example 8.

[0063] Symbol Explanation

[0064] G1…First lens group

[0065] G2…Second lens group

[0066] G3…Third Lens Group

[0067] G4…Fourth Lens Group

[0068] G5…Fifth Lens Group

[0069] G5A…Fifth A Lens Group

[0070] G5B…Fifth B Lens Group

[0071] G6…Sixth Lens Group

[0072] G7…Seventh Lens Group

[0073] S…Aperture Stop

[0074] IP…Image Detailed Implementation

[0075] Hereinafter, embodiments of the zoom lens and imaging device according to the present invention will be described. However, the zoom lens and imaging device described below are one embodiment of the zoom lens and imaging device according to the present invention, and the zoom lens and imaging device according to the present invention are not limited to the following embodiment.

[0076] 1. Zoom lens

[0077] 1-1. Composition

[0078] First, an embodiment of the zoom lens according to the present invention will be described. The zoom lens of this embodiment comprises, in sequence 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 positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group, and the spacing between adjacent lens groups on the optical axis changes during zooming.

[0079] This zoom lens employs the above-described configuration, achieving magnification by changing the spacing between adjacent lens groups during zooming. Having at least six lens groups, this zoom lens offers high freedom of movement in both the amount and direction of movement for each lens group during zooming. Therefore, by adopting this configuration, a high zoom ratio can be easily achieved, and aberration variations throughout the entire zoom range can be suppressed, resulting in a high-performance zoom lens.

[0080] (1) First lens group

[0081] As long as the first lens group has positive refractive power, its specific lens configuration is not particularly limited. For example, by using a configuration that includes two positive lenses, a strong positive refractive power can be provided to the first lens group, making it easy to obtain a zoom lens that achieves a high zoom ratio and a short overall optical length at the telephoto end. In addition, by using a configuration that includes at least one negative lens, spherical aberration can be easily corrected, which is therefore more ideal.

[0082] (2) Second lens group

[0083] As long as the second lens group has negative refractive power, its specific lens configuration is not particularly limited. For example, by using a configuration that includes two or more negative lenses, and configuring the second lens group with strong negative refractive power, it is easy to obtain a zoom lens that achieves a high zoom ratio and a short total optical length at the telephoto end.

[0084] Furthermore, it is preferable that at least one surface of the lens in the second lens group positioned closest to the image side is aspherical. By adopting this configuration, the balance between coma on the wide-angle side and spherical aberration on the telephoto side can be well corrected.

[0085] (3) The third and fourth lens groups

[0086] The specific lens configuration of the third and fourth lens groups is not particularly limited as long as they each possess positive refractive power. However, it is preferable, for example, that at least one of the third and fourth lens groups has a positive lens on its object-side closest side. By arranging a positive lens on the object-side closest side of at least one of the third and fourth lens groups, it is easy to use lenses with small diameters to construct the lens groups positioned after the third lens group, thereby facilitating radial miniaturization of the zoom lens. At the same time, by adopting this configuration, it is easy to position the exit pupil closer to the image plane, thereby easily ensuring peripheral light. From the perspective of achieving this effect, it is preferable to arrange positive lenses on the object-side closest side of both the third and fourth lens groups. Furthermore, the shape of the positive lens is not particularly limited, but from the perspective of achieving the above-mentioned effect, it is more preferable that it has a convex surface on the object side. In addition, from the perspective of aberration correction, it is preferable that each lens group has at least one negative lens.

[0087] (4) Fifth lens group

[0088] The specific lens configuration of the fifth lens group is not particularly limited as long as it has negative refractive power, but it is preferably, for example, a fifth A lens group with negative refractive power and a fifth B lens group with either positive or negative refractive power, arranged sequentially from the object side. In this case, by configuring the fifth A lens group to be movable in a direction perpendicular to the optical axis, the fifth A lens group can be used as an image stabilization group. That is, when the zoom lens vibrates due to hand tremors, etc., by moving the fifth A lens group in a direction perpendicular to the optical axis, image shake caused by the vibration can be corrected.

[0089] In this zoom lens, both the third and fourth lens groups have positive refractive power. Therefore, the beam converged in the third and fourth lens groups enters the fifth A lens group. Thus, the fifth A lens group can be constructed from lenses with small diameters. Therefore, by using the fifth A lens group as the image stabilization group, it is easy to miniaturize and reduce the weight of the image stabilization group. Furthermore, it is also possible to miniaturize and reduce the weight of the drive mechanism used to move the image stabilization group in a direction perpendicular to the optical axis. This allows for the miniaturization and weight reduction of the entire zoom lens unit.

[0090] Preferably, the fifth lens group has at least two positive lenses. By arranging at least two positive lenses in the fifth lens group, which has negative refractive power, it is possible to achieve a smaller diameter in the lens group that is positioned closer to the image side than the fifth lens group itself, thereby making it easier to ensure peripheral light quantity. From the perspective of obtaining this effect, it is preferable to arrange the positive lens on the image side of the fifth lens group, and more preferably, to arrange the positive lens on the image side of the fifth lens group. When the fifth lens group is composed of the aforementioned fifth A lens group and the aforementioned fifth B lens group, it is preferable, for example, that each of the fifth A lens group and the fifth B lens group has one positive lens, and from the perspective of obtaining the aforementioned effect, it is more preferable to arrange the positive lens on the image side of the fifth B lens group.

[0091] (5) Sixth lens group

[0092] The refractive power of the sixth lens group can be either positive or negative, but it is preferable that it satisfies conditions (2) and (5) described later. When the sixth lens group has positive refractive power, the negative distortion aberration generated in the second lens group can be eliminated by making the sixth lens group produce positive distortion aberration. From this point of view, it is more preferable that the sixth lens group has positive refractive power.

[0093] (6) Other lens groups

[0094] The zoom lens may also have other lens groups, such as a seventh lens group, on the image side of the sixth lens group. That is, the zoom lens is not limited to a six-group structure of positive-negative-positive-positive-negative-positive or positive-negative-positive-positive-negative-negative, and may also have one or more lens groups with positive or negative refractive power on the image side of the sixth lens group.

[0095] However, as the number of lens groups constituting the zoom lens increases, it becomes difficult to miniaturize and lighten the zoom lens. Furthermore, as the number of lens groups increases, the zoom mechanism used to move each lens group during zooming becomes more complex, and the overall zoom lens unit tends to become larger. Based on these considerations, the number of lens groups constituting the zoom lens is preferably 6 to 8, more preferably 6 or 7.

[0096] Furthermore, from the viewpoint of ensuring peripheral light and effectively correcting distortion aberrations, it is preferable that the lens group located on the image side of the sixth lens group has positive refractive power.

[0097] (7) Aperture stop

[0098] In the zoom lens of this embodiment, it is preferable to arrange the aperture stop, for example, on the object side or image plane side of the third lens group, or within the third lens group, and it is particularly preferable to arrange the aperture stop on the object side of the third lens group. When the aperture stop is arranged on the object side of the third lens group, it is easy to reduce the effective diameter of the first lens group at the wide-angle end, thereby enabling both the assurance of peripheral light and the miniaturization of the filter diameter to be achieved simultaneously.

[0099] 1-2. Actions

[0100] (1) Zoom

[0101] In this zoom lens, as described above, magnification is achieved by changing the spacing along the optical axis between the lens groups. Any change in the spacing along the optical axis between the lens groups during zooming is acceptable; either all lens groups can move along the optical axis, or a portion of the lens groups can remain fixed along the optical axis. The amount and direction of movement of each lens group are not particularly limited as long as the desired zoom ratio is achieved, but it is preferable to set them as follows, for example.

[0102] When zooming from the wide-angle end to the telephoto end, the first, third, fourth, fifth, and sixth lens groups are preferably moved along the optical axis such that they are positioned on the object side at the telephoto end relative to their positions on the optical axis at the wide-angle end. By moving each lens group in this way, miniaturization of the overall optical length at the wide-angle end is easily achieved. Furthermore, by shortening the overall optical length at the wide-angle end, peripheral light levels at the wide-angle end are easily ensured. Moreover, the movement paths of the first, third, fourth, fifth, and sixth lens groups during zooming can be linear, or they can temporarily move towards the image side or object side and then move in the opposite direction. That is, they can also move in a manner that traces a convex trajectory on the image side or object side. Additionally, they can move in a manner that traces an S-shaped or inverted S-shaped trajectory. That is, the movement trajectory of each lens group (first lens group, third lens group, fourth lens group, fifth lens group and sixth lens group) is not particularly limited as long as the position of each lens group is on the object side at the telephoto end compared to the wide-angle end, and they can be moved in any way.

[0103] To achieve high zoom capability and suppress aberrations throughout the zoom range, it is preferable to move the second lens group towards the image side to a predetermined intermediate focal length position when zooming from the wide-angle end to the telephoto end, and then move the second lens group from the predetermined intermediate focal length position towards the telephoto end to the object side. In this way, by moving the second lens group towards the image side from the wide-angle end to the predetermined intermediate focal length position, the combined zoom ratio from the third lens group to the final lens group can be enhanced within the wide-angle zoom range. That is, within the wide-angle zoom range, the amount of movement of lens groups after the third lens group can be suppressed while zooming from the wide-angle end to the predetermined intermediate focal length position. Furthermore, by moving the second lens group from the predetermined intermediate focal length position towards the object side, zooming can be performed while appropriately maintaining the zoom function of the second lens group. Therefore, it is difficult to place an excessive zoom burden on each lens group, thereby suppressing aberrations and achieving high zoom capability.

[0104] Furthermore, during zooming, the second lens group can be moved from the aforementioned intermediate focal length position toward the telephoto end towards the object side, and then moved again toward the image side. That is, when zooming from the wide-angle end to the telephoto end, the second lens group can be moved toward the image side from the wide-angle end to the first intermediate focal length position, toward the object side from the first intermediate focal length position to the second intermediate focal length position, and then again toward the image side from the second intermediate focal length position toward the telephoto end. By moving the second lens group in such an S-shape between the wide-angle end and the telephoto end, the overall optical length of the zoom lens at the telephoto end can be suppressed, thereby easily achieving a high zoom ratio and miniaturizing the zoom lens.

[0105] Furthermore, when the focal length of the zoom lens at the wide-angle end is set to fw, the focal length of the zoom lens at the telephoto end is set to ft, the focal length at the first intermediate focal length position is set to fm1, and the focal length at the second intermediate focal length position is set to fm2, the following relationship is preferably satisfied.

[0106] fw<fm1≤(fw×ft) 1 / 2

[0107] (fw×ft) 1 / 2 <fm2<ft

[0108] Furthermore, when zooming from the wide-angle end to the telephoto end, it is preferable to move the third and fourth lens groups in such a way that the distance between the third and fourth lens groups on the optical axis narrows. At the wide-angle end, by increasing the distance between the third and fourth lens groups on the optical axis, the diverging light emitted from the second lens group can be converged more effectively using the third and fourth lens groups, which have positive refractive power. This allows the effective diameter of the lens groups after the third lens group to be kept smaller, thereby easily ensuring the amount of peripheral light.

[0109] Furthermore, when zooming from the wide-angle end to the telephoto end, it is preferable to move each lens group in such a way that the optical axis spacing between the first and second lens groups increases, the optical axis spacing between the second and third lens groups decreases, the optical axis spacing between the fourth and fifth lens groups increases, and the optical axis spacing between the fifth and sixth lens groups decreases. By moving each lens group in this way during zooming, it is difficult to burden the magnification function of each group, thereby enabling both high magnification and high performance to be achieved simultaneously.

[0110] Furthermore, when zooming from the wide-angle end to the telephoto end, it is preferable to move the fourth and sixth lens groups along the same trajectory. By moving the fourth and sixth lens groups along the same trajectory, it is possible to integrate the fourth and sixth lens groups into a single structure. In zoom lenses, the lens barrel is typically designed with a double or multiple nested structure, and the inner or outer barrel is rotated while the pin is engaged with a cam groove provided on the side of the inner or outer barrel, thereby changing the position of each lens group. By integrating the fourth and sixth lens groups into a single structure, the cam structure can be simplified, making it easier to miniaturize the lens barrel. Furthermore, by integrating the fourth and sixth lens groups into a single structure, the relative misalignment between the fourth and sixth lens groups that occurs during zooming can be minimized, thus suppressing the deterioration of optical performance due to manufacturing errors. In addition, moving along the same trajectory means that the spacing between the fourth and sixth lens groups on the optical axis does not change during zooming, and the spacing is the same at any zoom position.

[0111] (2) Focus

[0112] In the zoom lens of this embodiment, it is preferable to move the second lens group along the optical axis when focusing from an object at infinity toward an object approaching it. By setting the second lens group, which is equipped with a strong negative refractive power, as the focusing group, the amount of movement of the second lens group during focusing can be reduced, thereby making it easier to miniaturize the overall optical length.

[0113] 1-3.Conditional expression

[0114] The zoom lens preferably adopts the above-described configuration and satisfies at least one of the following conditions.

[0115] 1-3-1.Conditional expression (1)

[0116] 0.10≤f34w / |f5|≤0.75……(1)

[0117] in,

[0118] f34w: The combined focal length from the third lens group to the fourth lens group at the wide-angle end.

[0119] f5: Focal length of the fifth lens group.

[0120] Condition (1) is a condition used to specify the ratio of the combined focal length of the third and fourth lens groups to the focal length of the fifth lens group at the wide-angle end. By satisfying condition (1), it is easy to ensure the peripheral light quantity at the wide-angle end and obtain a zoom lens with high optical performance.

[0121] Conversely, when the value of conditional equation (1) falls below the lower limit, while it is easy to ensure peripheral light at the wide-angle end, it is difficult to properly correct various aberrations occurring in the third to fifth lens groups, especially spherical aberration at the telephoto end. Furthermore, in this case, the back focal length of the zoom lens at the wide-angle end becomes shorter. Therefore, when this zoom lens is applied to interchangeable lenses for SLR cameras, it is difficult to ensure an appropriate back focal length. When the upper limit of conditional equation (1) is exceeded, the positive combined refractive power from the third to fifth lens groups weakens, making it difficult to bring the exit pupil position close to the image plane, thus making it difficult to ensure peripheral light.

[0122] From the perspective of achieving the above-mentioned effects, the upper limit of conditional expression (1) is preferably 0.70, more preferably 0.65, and even more preferably 0.60. In addition, the lower limit of conditional expression (1) is preferably 0.15, and more preferably 0.20.

[0123] 1-3-2.Conditional expression (2)

[0124] -0.5≤fw / f5iw≤0.2……(2)

[0125] in,

[0126] fw: The focal length of the zoom lens at the wide-angle end.

[0127] f5iw: The combined focal length from the fifth lens group at the wide-angle end to the lens group located on the image side of the zoom lens.

[0128] Condition (2) is a condition used to specify the ratio of the focal length of the zoom lens at the wide-angle end to the combined focal length from the fifth lens group to the image-side lens group at the wide-angle end. By satisfying condition (2), it is possible to miniaturize the zoom lens along its overall length and to achieve a zoom lens that also effectively corrects image plane curvature at the wide-angle end.

[0129] Conversely, when the value of conditional equation (2) falls below the lower limit, the telephoto tendency of the zoom lens becomes stronger. That is, the telephoto ratio becomes too small. In this case, the amount of movement of each lens group during zooming can be suppressed, so it is ideal from the perspective of miniaturization in the overall length direction. However, since a large overcorrected image plane curvature occurs at the wide-angle end, a large number of lenses are required for aberration correction. When the value of conditional equation (2) falls above the upper limit, the telephoto tendency weakens, so the amount of movement of each lens group during zooming increases, making it difficult to achieve miniaturization in the overall length direction. In addition, since a large undercorrected image plane curvature occurs at the wide-angle end, a large number of lenses are required for aberration correction.

[0130] From the perspective of achieving the above-mentioned effect, the upper limit of conditional expression (2) is preferably 0.1, more preferably 0.0. In addition, the lower limit of conditional expression (2) is preferably -0.40, more preferably -0.35, and even more preferably -0.30.

[0131] 1-3-3.Conditional expression (3)

[0132] 2.5≤f1 / fw≤9.0……(3)

[0133] in,

[0134] f1: Focal length of the first lens group

[0135] fw: The focal length of the zoom lens at the wide-angle end.

[0136] Condition (3) is a condition used to specify the ratio of the focal length of the first lens group to the focal length of the zoom lens at the wide-angle end. By satisfying condition (3), the zoom lens can be miniaturized and wide-angle (e.g., a half angle of view of 40 degrees or more) can be achieved.

[0137] In contrast, when the value of conditional equation (3) is below the lower limit, the strong refractive power of the first lens group allows for a smaller amount of movement of the first lens group during zooming, which is beneficial for miniaturizing the overall length of the zoom lens. However, it is difficult to achieve the specified angle of view at the wide-angle end. Achieving the specified angle of view at the wide-angle end requires increasing the negative refractive power of the second lens group, which makes correction of image plane curvature difficult. On the other hand, when the value of conditional equation (3) is above the upper limit, the weak refractive power of the first lens group results in a larger amount of movement of the first lens group during zooming to achieve a high zoom ratio. Furthermore, the larger aperture and the larger diameter of subsequent lens groups make it difficult to miniaturize the zoom lens.

[0138] From the perspective of achieving the above-mentioned effects, the upper limit of conditional expression (3) is preferably 8.0, more preferably 7.0, and even more preferably 6.0. In addition, the lower limit of conditional expression (3) is preferably 3.5, more preferably 4.0, and even more preferably 4.5.

[0139] 1-3-4.Conditional expression (4)

[0140] 4.0≤T3w / Y≤8.0……(4)

[0141] in,

[0142] T3w: The distance along the optical axis from the object-side surface of the third lens group at the wide-angle end to the image plane.

[0143] Y: Maximum image height at the wide-angle end.

[0144] By satisfying condition (4), aberration variations throughout the zoom range can be suppressed, and wide-angle and high-magnification zoom of the zoom lens can be achieved at the wide-angle end. Conversely, when the value of condition (4) is below the lower limit, wide-angle zoom is easily achieved, but aberration variations during zoom are difficult to suppress, and high-magnification zoom is difficult to achieve. On the other hand, when the value of condition (4) is above the upper limit, the total optical length of the zoom lens at the wide-angle end becomes longer, making it difficult to ensure peripheral light.

[0145] From the perspective of achieving the above-mentioned effects, the upper limit of conditional expression (4) is preferably 7.0, more preferably 6.5, and even more preferably 6.0. In addition, the lower limit of conditional expression (4) is preferably 4.3, more preferably 4.5.

[0146] 1-3-5.Conditional expression (5)

[0147] -0.10≤f345w / f6iw≤0.70……(5)

[0148] in,

[0149] f345w: The combined focal length from the third lens group to the fifth lens group at the wide-angle end.

[0150] f6iw: The combined focal length from the sixth lens group at the wide-angle end to the lens group located on the image side of the zoom lens.

[0151] Condition (5) is a condition used to specify the ratio of the combined focal length from the third to the fifth lens group at the wide-angle end to the combined focal length from the sixth lens group to the lens group positioned closest to the image side in the zoom lens. By satisfying condition (5), peripheral light quantity can be easily ensured even at the wide-angle end. Here, it is usually difficult to correct distortion aberration when the zoom lens achieves a wide angle. In order to correct distortion aberration well at the wide-angle end, it is necessary to eliminate the negative distortion aberration generated in the second lens group by making the lens groups positioned after the third lens group produce positive distortion aberration. In particular, the lens groups positioned further to the image side in the zoom lens after the sixth lens group are most prone to positive distortion aberration compared to other lens groups. Therefore, by setting the range that satisfies condition (5), the ratio of the combined refractive power from the third lens group to the fifth lens group to the combined refractive power of the lens groups after the sixth lens group becomes appropriate, and distortion aberration can be well corrected at the wide-angle end, thereby obtaining a zoom lens with high optical performance throughout the zoom range.

[0152] Conversely, when the value of conditional equation (5) is below the lower limit, the amount of positive distortion aberration generated in the lens groups after the third lens group becomes smaller, making it difficult to properly correct the distortion aberration of the zoom lens at the wide-angle end. On the other hand, when the value of conditional equation (5) is above the upper limit, the positive combined refractive power from the third lens group to the fifth lens group becomes weaker, making it difficult to bring the exit pupil position close to the image plane side, thus making it difficult to ensure the amount of peripheral light.

[0153] From the perspective of achieving the above-mentioned effects, the upper limit of conditional expression (5) is preferably 0.65, more preferably 0.60, and even more preferably 0.55. In addition, the lower limit of conditional expression (5) is preferably 0.0, and more preferably 0.10.

[0154] 1-3-6.Conditional expression (6)

[0155] 0.04≤|f2| / ft≤0.21……(6)

[0156] in,

[0157] f2: Focal length of the second lens group

[0158] ft: The focal length of the zoom lens at the telephoto end.

[0159] Condition (6) is a condition used to specify the ratio of the focal length of the second lens group to the focal length of the zoom lens at the telephoto end. By satisfying condition (6), good optical performance can be obtained, and the specified zoom ratio can be ensured.

[0160] Conversely, when the value of condition (6) falls below the lower limit, the negative refractive power of the second lens group becomes excessively strong and exceeds the appropriate range, making it difficult to correct distortion aberrations and image plane curvature. On the other hand, when the value of condition (6) exceeds the upper limit, it becomes difficult to achieve the specified zoom ratio. In order to obtain the specified zoom ratio, it is necessary to reduce the refractive power of the first lens group. As a result, the amount of movement of the first lens group during zooming increases, making it difficult to shorten the overall length of the zoom lens.

[0161] From the perspective of achieving the above-mentioned effects, the upper limit of conditional expression (6) is preferably 0.20, and more preferably 0.19. In addition, the lower limit of conditional expression (6) is preferably 0.06, and more preferably 0.07.

[0162] 1-3-7.Conditional expression (7)

[0163] -6.0≤Cr2r / fw≤-0.9……(7)

[0164] in,

[0165] Cr2r: The radius of curvature of the surface closest to the image side of the second lens group.

[0166] fw: The focal length of the zoom lens at the wide-angle end.

[0167] Condition (7) is a condition used to specify the ratio of the radius of curvature of the image-side surface of the second lens group to the focal length of the zoom lens at the wide-angle end. By satisfying condition (7), spherical aberration and coma can be corrected in a balanced manner throughout the zoom range.

[0168] When the value of condition (7) is below the lower limit, it is difficult to correct coma on the wide-angle side of the zoom range. When the value of condition (7) is above the upper limit, it is difficult to correct spherical aberration on the telephoto side of the zoom range.

[0169] The upper limit of condition (7) is preferably -1.0, more preferably -1.1, and even more preferably -1.2. In addition, the lower limit of condition (7) is preferably -5.5, more preferably -5.0.

[0170] 1-3-8.Conditional expression (8)

[0171] 1.45≤BFw / Y……(8)

[0172] in,

[0173] BFw: The back focal length of the zoom lens at the wide-angle end.

[0174] Y: Maximum image height at the wide-angle end.

[0175] Condition (8) is a condition used to specify the ratio of the back focal length of the zoom lens at the wide-angle end to the maximum image height of the zoom lens at the wide-angle end. By satisfying condition (7), the appropriate back focal length required for interchangeable lenses used in SLR cameras can be ensured. Without satisfying condition (8), it is difficult to apply this zoom lens to interchangeable lenses used in SLR cameras. However, it is more ideal from the perspective of miniaturization in the overall length direction at the wide-angle end when using this zoom lens in the imaging optical system of various imaging devices such as mirrorless cameras that do not have a mirror box.

[0176] 1-3-9.Conditional expression (9)

[0177] 1.0≤(ft / fw) / Fnom≤5.0……(9)

[0178] in,

[0179] ft: The focal length of the zoom lens at the telephoto end.

[0180] fw: The focal length of the zoom lens at the wide-angle end.

[0181] Fnom = (Fnot × Fnow)1 / 2 ,

[0182] Fnot: The F-number of the zoom lens at the telephoto end.

[0183] Fnow: The F-number of the zoom lens at the wide-angle end.

[0184] Condition (9) is a condition used to specify the ratio of the zoom ratio of the zoom lens to the F-value at the intermediate focal length position. By satisfying condition (9), wide-angle and high zoom can be easily achieved, and zoom lenses with rich peripheral light and high optical performance can be easily obtained.

[0185] In contrast, when the value of condition (9) is below the lower limit, the overall length is easily miniaturized due to the small zoom ratio or dim F-value, and the ambient light intensity can be easily ensured regardless of the present invention. On the other hand, when the value of condition (9) is above the upper limit, the overall length is easily enlarged due to the high zoom ratio or bright F-value. Therefore, it is difficult to ensure sufficient ambient light intensity.

[0186] 2. Camera device

[0187] Next, the imaging apparatus of the present invention will be described. The imaging apparatus of the present invention is characterized by comprising: the zoom lens of the present invention described above, and an imaging element that converts the optical image formed by the zoom lens into an electrical signal on the image plane side of the zoom lens.

[0188] Here, the imaging element is not particularly limited, and solid-state imaging elements such as CCD (Charge Coupled Device) sensors and CMOS (Complementary Metal Oxide Semiconductor) sensors can also be used. The imaging device of the present invention is applicable to imaging devices such as digital cameras and camcorders that use these solid-state imaging elements. Furthermore, this imaging device can be a lens-fixed imaging device with the lens fixed to the frame, or it can be a lens-interchangeable imaging device such as an SLR camera or a mirrorless camera. In particular, the zoom lens of the present invention ensures a suitable back focal length for interchangeable lens systems. Therefore, it is applicable to imaging devices such as SLR cameras that include an optical viewfinder, a phase difference sensor, and a reflector that branches light in these components.

[0189] Next, the present invention will be specifically described by way of examples. However, the present invention is not limited to the following examples.

[0190]

Example 1

[0191] (1) Optical structure of zoom lens

[0192] Figure 1 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 1 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3. Zooming is achieved by varying the spacing along the optical axis between the lens groups as described later.

[0193] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0194] The second lens group G2, starting from the object side, comprises: a negative meniscus lens L4 with its convex surface facing the object side, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the negative meniscus lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical shapes on both sides.

[0195] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0196] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0197] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with positive refractive power. The fifth A lens group G5A is configured to move in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to factors such as hand tremors, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0198] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 with its convex surface facing the image side and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a negative meniscus lens L16 with its convex surface facing the image side and a positive meniscus lens L17 with its convex surface facing the object side, cemented sequentially from the object side.

[0199] The sixth lens group G6, starting from the object side, consists of a biconvex lens L18, and a cemented lens formed by cementing a negative meniscus lens L19 (convex side facing the object) and a positive meniscus lens L20 (convex side facing the object). The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0200] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0201] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0202] also, Figure 1 The "IP" shown refers to the imaging surface, specifically the imaging surface of a solid-state imaging element such as a CCD sensor or CMOS sensor, or the film surface of a silver halide film. Additionally, although not shown in the illustration, a parallel plate without substantial refractive power, such as a glass cover plate, may be provided on the object side of the imaging surface IP. These points are also the same in the lens cross-sectional views shown in other embodiments, and therefore, descriptions are omitted below.

[0203] (2) Numerical Examples

[0204] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 1 shows the surface data of the zoom lens. In Table 1, "surface number" indicates the order of the lens surfaces counting from the object side, "R" indicates the radius of curvature of the lens surface, "D" indicates the spacing on the optical axis of the lens surface, "Nd" indicates the refractive index relative to the d-line (wavelength λ = 587.6 nm), and "ABV" indicates the Abbe number relative to the d-line. In addition, "ASPH" shown in the column below the surface number indicates that the lens surface is aspherical, and "STOP" indicates the aperture stop. Furthermore, the column for the spacing on the optical axis of the lens surface is indicated as "D(0)", "D(5)", etc., which means that the spacing on the optical axis of the lens surface is a variable spacing that changes when zooming. In addition, the unit of length in each table is "mm", and the unit of angle of view is "°". In addition, "0" and "∞ (infinity)" for the radius of curvature indicate a plane.

[0205] Table 2 is the specification table of the zoom lens. This table shows the focal length "f", F-number "Fno", half angle of view "ω", and image height "Y" of the zoom lens when focusing at infinity. Specifically, Table 2 shows the values ​​for the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and the telephoto end, from left to right. Furthermore, the first intermediate focal length position and the second intermediate focal length position correspond to "fm1" and "fm2" as described in the above embodiment.

[0206] Table 3 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity. From left to right, the values ​​for the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and the telephoto end are shown in Table 3. Furthermore, "INF" in the table represents "∞ (infinity)".

[0207] Table 4 shows the variable spacing on the optical axis of the zoom lens when focusing on a close object at a shooting distance (viewing distance) of 1m. Table 4 shows the values ​​for the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and the telephoto end. In addition, "INF" in the table means "∞ (infinity)".

[0208] Table 5 shows the focal lengths of each lens group that makes up the zoom lens.

[0209] Table 6 shows the aspheric coefficients for each aspheric surface. These aspheric coefficients are the values ​​defined by the following formula for each aspheric surface shape. Additionally, Table 49 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 51 shows the values ​​of the variables required to obtain the values ​​of conditional expressions (1) to (9).

[0210] X(Y)=CY 2 / [1+{1-(1+K)·C 2 Y 2} 1 / 2 ]+A4·Y 4 +A6·Y 6 +A8·Y 8 +A10·Y 10 +A12·Y 12

[0211] In Table 6, “Ea” represents “×10”. -a In addition, in the above formula, "X" is the displacement from the reference plane in the direction of the optical axis, "C" is the curvature at the vertex of the surface (C = 1 / R, "R" is the radius of curvature of the lens surface), "Y" is the height from the optical axis in the direction perpendicular to the optical axis, "K" is the conic coefficient, and "An" is the aspheric coefficient of the nth order.

[0212] The matters covered in these tables are the same as those in the tables shown in other embodiments, and therefore the description is omitted below.

[0213] [Table 1]

[0214]

[0215]

[0216] [Table 2]

[0217]

[0218] [Table 3]

[0219] Variable interval [when focusing at infinity]

[0220]

[0221] [Table 4]

[0222] Variable interval [when focusing at a shooting distance of 1m]

[0223]

[0224] [Table 5]

[0225]

[0226]

[0227] [Table 6]

[0228] Aspheric coefficient

[0229]

[0230] in addition, Figures 2-5 The following figures show longitudinal aberration diagrams for focusing the zoom lens of Embodiment 1 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end. The longitudinal aberration diagrams shown in each figure, facing the left side of the graph, represent spherical aberration (mm), astigmatism (mm), and distortion aberration (%), respectively. In the diagram representing spherical aberration, the vertical axis represents the ratio to the open F-number, and the horizontal axis represents defocus. The solid line represents the spherical aberration of the d-line (wavelength 587.56 nm), and the dashed line represents the spherical aberration of the g-line (wavelength 435.84 nm). In the diagram representing astigmatism, the vertical axis represents the half-angle view, and the horizontal axis represents defocus. The solid line represents the sagittal image plane (ds) relative to the d-line, and the dashed line represents the meridional image plane (dm) relative to the d-line. In the diagram representing distortion aberration, the vertical axis represents the half-angle view, and the horizontal axis represents %, indicating distortion aberration. The matters involved in these longitudinal aberration diagrams are the same as those shown in the longitudinal aberration diagrams in other embodiments, and therefore, the following description is omitted.

[0231]

Example 2

[0232] (1) Optical structure of zoom lens

[0233] Figure 6 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 2 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with negative refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3. Zooming is achieved by varying the spacing along the optical axis between the lens groups as described later.

[0234] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0235] The second lens group G2, starting from the object side, consists of a biconcave lens L4, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the biconcave lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical surfaces on both sides.

[0236] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0237] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0238] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with positive refractive power. The fifth A lens group G5A is configured to move in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to factors such as hand tremors, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0239] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 (convex side facing the image side) and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a biconcave lens L16 and a positive meniscus lens L17 (convex side facing the object side), sequentially from the object side.

[0240] The sixth lens group G6, starting from the object side, consists of a biconvex lens L18, and a cemented lens formed by cementing a negative meniscus lens L19 (convex side facing the object) and a positive meniscus lens L20 (convex side facing the object). The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0241] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, and then moves towards the image side again, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0242] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0243] (2) Numerical Examples

[0244] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 7 shows the surface data of the zoom lens, and Table 8 shows the specifications of the zoom lens. Table 9 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 10 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 11 shows the focal lengths of each lens group constituting the zoom lens. Table 12 shows the aspherical coefficients of each aspherical surface. In addition, Table 49 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 51 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 7-10 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 2 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0245] [Table 7]

[0246]

[0247]

[0248] [Table 8]

[0249]

[0250] [Table 9]

[0251] Variable interval [when focusing at infinity]

[0252]

[0253] [Table 10]

[0254] Variable interval [when focusing at a shooting distance of 1m]

[0255]

[0256] [Table 11]

[0257]

[0258]

[0259] [Table 12]

[0260] Aspheric coefficient

[0261]

[0262]

Example 3

[0263] (1) Optical structure of zoom lens

[0264] Figure 11 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 3 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3.

[0265] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0266] The second lens group G2, starting from the object side, consists of a biconcave lens L4, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the biconcave lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical surfaces on both sides.

[0267] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0268] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0269] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with positive refractive power. The fifth A lens group G5A is configured to move in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to factors such as hand tremors, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0270] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 with its convex surface facing the image side and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a negative meniscus lens L16 with its convex surface facing the object side and a positive meniscus lens L17 with its convex surface facing the object side, cemented sequentially from the object side.

[0271] The sixth lens group G6, starting from the object side, consists of a cemented lens composed of a biconvex lens L18, a negative meniscus lens L19 with its convex surface facing the object side, and a positive meniscus lens L20 with its convex surface facing the object side. The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0272] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, and then moves towards the image side again, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0273] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0274] (2) Numerical Examples

[0275] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 13 shows the surface data of the zoom lens, and Table 14 shows the specifications of the zoom lens. Table 15 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 16 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 17 shows the focal lengths of each lens group constituting the zoom lens. Table 18 shows the aspherical coefficients of each aspherical surface. In addition, Table 49 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 51 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 12-15 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 3 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0276] [Table 13]

[0277]

[0278]

[0279] [Table 14]

[0280]

[0281] [Table 15]

[0282] Variable interval [when focusing at infinity]

[0283]

[0284] [Table 16]

[0285] Variable interval [when focusing at a shooting distance of 1m]

[0286]

[0287] [Table 17]

[0288]

[0289] [Table 18]

[0290] Aspheric coefficient

[0291]

[0292]

[0293]

Example 4

[0294] (1) Optical structure of zoom lens

[0295] Figure 16 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 4 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3.

[0296] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0297] The second lens group G2, starting from the object side, consists of a biconcave lens L4, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the biconcave lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical surfaces on both sides.

[0298] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0299] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0300] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with positive refractive power. The fifth A lens group G5A is configured to move in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to factors such as hand tremors, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0301] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 (convex side facing the image side) and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a biconcave lens L16 and a positive meniscus lens L17 (convex side facing the object side), sequentially from the object side.

[0302] The sixth lens group G6, starting from the object side, consists of a cemented lens composed of a biconvex lens L18, a negative meniscus lens L19 with its convex surface facing the object side, and a positive meniscus lens L20 with its convex surface facing the object side. The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0303] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, and then moves towards the image side again, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0304] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0305] (2) Numerical Examples

[0306] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 19 shows the surface data of the zoom lens, and Table 20 shows the specifications of the zoom lens. Table 21 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 22 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 23 shows the focal lengths of each lens group constituting the zoom lens. Table 24 shows the aspherical coefficients of each aspherical surface. In addition, Table 49 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 51 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 17-20 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 4 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0307] [Table 19]

[0308]

[0309]

[0310] [Table 20]

[0311]

[0312] [Table 21]

[0313] Variable interval [when focusing at infinity]

[0314]

[0315]

[0316] [Table 22]

[0317] Variable interval [when focusing at a shooting distance of 1m]

[0318]

[0319] [Table 23]

[0320]

[0321] [Table 24]

[0322] Aspheric coefficient

[0323]

[0324]

Example 5

[0325] (1) Optical structure of zoom lens

[0326] Figure 21 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 5 of the present invention. The zoom lens, from the object side, sequentially comprises: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3.

[0327] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0328] The second lens group G2, starting from the object side, consists of a biconcave lens L4, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the biconcave lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical surfaces on both sides.

[0329] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0330] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0331] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with negative refractive power. The fifth A lens group G5A is configured to be movable in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to hand tremors or other reasons, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0332] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 (convex side facing the image side) and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a biconcave lens L16 and a positive meniscus lens L17 (convex side facing the object side), sequentially from the object side.

[0333] The sixth lens group G6, starting from the object side, consists of a cemented lens composed of a biconvex lens L18, a negative meniscus lens L19 with its convex surface facing the object side, and a positive meniscus lens L20 with its convex surface facing the object side. The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0334] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0335] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0336] (2) Numerical Examples

[0337] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 25 shows the surface data of the zoom lens, and Table 26 shows the specifications of the zoom lens. Table 27 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 28 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 29 shows the focal lengths of each lens group constituting the zoom lens. Table 30 shows the aspherical coefficients of each aspherical surface. In addition, Table 50 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 52 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 22-25 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 5 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0338] [Table 25]

[0339]

[0340]

[0341] [Table 26]

[0342]

[0343] [Table 27]

[0344] Variable interval [when focusing at infinity]

[0345]

[0346] [Table 28]

[0347] Variable interval [when focusing at a shooting distance of 1m]

[0348]

[0349]

[0350] [Table 29]

[0351]

[0352] [Table 30]

[0353] Aspheric coefficient

[0354]

[0355]

Example 6

[0356] (1) Optical structure of zoom lens

[0357] Figure 26 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 6 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, a sixth lens group G6 with positive refractive power, and a seventh lens group G7 with positive refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3.

[0358] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0359] The second lens group G2, starting from the object side, comprises: a negative meniscus lens L4 with its convex surface facing the object side, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the negative meniscus lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical shapes on both sides.

[0360] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0361] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0362] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with negative refractive power. The fifth A lens group G5A is configured to be movable in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to hand tremors or other reasons, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0363] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 with its convex surface facing the image side and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a negative meniscus lens L16 with its convex surface facing the image side and a positive meniscus lens L17 with its convex surface facing the object side, cemented sequentially from the object side.

[0364] The sixth lens group G6, starting from the object side, consists of a biconvex lens L18, and a cemented lens formed by cementing a negative meniscus lens L19 (convex side facing the object) and a positive meniscus lens L20 (convex side facing the object). The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0365] The seventh lens group G7 consists of positive meniscus lenses with convex surfaces facing the image side, starting from the object side.

[0366] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, the sixth lens group G6 moves towards the object side, and the seventh lens group G7 is fixed on the optical axis. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0367] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0368] (2) Numerical Examples

[0369] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 31 shows the surface data of the zoom lens, and Table 32 shows the specifications of the zoom lens. Table 33 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 34 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 35 shows the focal lengths of each lens group constituting the zoom lens. Table 36 shows the aspherical coefficients of each aspherical surface. In addition, Table 50 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 52 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 27-30 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 6 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0370] [Table 31]

[0371]

[0372]

[0373] [Table 32]

[0374]

[0375] [Table 33]

[0376] Variable interval [when focusing at infinity]

[0377]

[0378] [Table 34]

[0379] Variable interval [when focusing at a shooting distance of 1m]

[0380]

[0381]

[0382] [Table 35]

[0383]

[0384] [Table 36]

[0385] Aspheric coefficient

[0386]

[0387]

Example 7

[0388] (1) Optical structure of zoom lens

[0389] Figure 31 This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 7 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, a sixth lens group G6 with positive refractive power, and a seventh lens group G7 with negative refractive power. An aperture stop S is disposed adjacent to the third lens group G3 on the object side of the third lens group G3.

[0390] The following describes the structure of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a biconvex lens L2, and a positive meniscus lens L3 with its convex surface facing the object side.

[0391] The second lens group G2, starting from the object side, comprises: a negative meniscus lens L4 with its convex surface facing the object side, a biconcave lens L5, a biconvex lens L6, and a negative meniscus lens L7 with its convex surface facing the image side. Both the negative meniscus lens L4 and the negative meniscus lens L7 are glass-molded aspherical lenses with aspherical shapes on both sides.

[0392] The third lens group G3, starting from the object side, consists of a biconvex lens L8 and a cemented lens formed by cementing a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0393] The fourth lens group G4, starting from the object side, consists of a biconvex lens L11, a negative meniscus lens L12 with its convex surface facing the object side, and a cemented lens formed by cementing the biconvex lens L13 together. The biconvex lens L11 is a glass-molded aspherical lens with two aspherical surfaces.

[0394] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with positive refractive power. The fifth A lens group G5A is configured to move in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to factors such as hand tremors, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0395] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L14 (convex side facing the image side) and a biconcave lens L15, cemented sequentially from the object side. The fifth lens group G5B consists of a biconcave lens L16 and a positive meniscus lens L17 (convex side facing the object side), sequentially from the object side.

[0396] The sixth lens group G6, starting from the object side, consists of a cemented lens composed of a biconvex lens L18, a negative meniscus lens L19 with its convex surface facing the object side, and a positive meniscus lens L20 with its convex surface facing the object side. The biconvex lens L18 is a glass-molded aspherical lens with two aspherical surfaces.

[0397] The seventh lens group G7 consists of negative meniscus lenses with their convex surfaces facing the object side, starting from the object side.

[0398] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, then moves towards the image side again, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, the sixth lens group G6 moves towards the object side, and the seventh lens group G7 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0399] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0400] (2) Numerical Examples

[0401] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 37 shows the surface data of the zoom lens, and Table 38 shows the specifications of the zoom lens. Table 39 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 40 shows the variable spacing on the optical axis of the zoom lens when focusing towards an approaching object at a shooting distance (viewing distance) of 1m. Table 41 shows the focal lengths of each lens group constituting the zoom lens. Table 42 shows the aspherical coefficients of each aspherical surface. In addition, Table 50 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 52 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 32-35 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 7 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0402] [Table 37]

[0403]

[0404]

[0405] [Table 38]

[0406]

[0407] [Table 39]

[0408] Variable interval [when focusing at infinity]

[0409]

[0410] [Table 40]

[0411] Variable interval [when focusing at a shooting distance of 1m]

[0412]

[0413] [Table 41]

[0414]

[0415]

[0416] [Table 42]

[0417]

[0418]

Example 8

[0419] (1) Optical structure of zoom lens

[0420] Figure 36This is a cross-sectional view of the zoom lens at infinity at the wide-angle end of Embodiment 8 of the present invention. The zoom lens, from the object side, comprises, in sequence: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power. An aperture stop is disposed adjacent to the object side of the third lens group G3.

[0421] The following describes the configuration of each lens group. The first lens group G1, starting from the object side, consists of a cemented lens formed by cementing a negative meniscus lens L1 with its convex surface facing the object side and a positive meniscus lens L2 with its convex surface facing the object side, and a positive meniscus lens L3 with its convex surface facing the object side.

[0422] The second lens group G2, starting from the object side, comprises: a negative meniscus lens L4 with its convex surface facing the object side; a cemented lens composed of a biconcave lens L5 and a biconvex lens L6; and a negative meniscus lens L7 with its convex surface facing the image side. The negative meniscus lens L4 is a composite resin aspherical lens formed by bonding a composite resin film molded into an aspherical shape to the object side. The negative meniscus lens L7 is a glass-molded aspherical lens with aspherical surfaces on both sides.

[0423] The third lens group G3, starting from the object side, includes a biconvex lens L8 and a negative meniscus lens L9 with its convex surface facing the object side. The biconvex lens L8 is a glass-molded aspherical lens with two aspherical surfaces.

[0424] The fourth lens group G4, starting from the object side, comprises: a cemented lens consisting of a negative meniscus lens L10 (convex side facing the object) and a biconvex lens L11, and a positive meniscus lens L12 (convex side facing the image). The positive meniscus lens L12 is a composite resin aspherical lens formed by bonding a composite resin film shaped into an aspherical surface to the object side.

[0425] The fifth lens group G5 consists of a fifth A lens group G5A with negative refractive power and a fifth B lens group G5B with negative refractive power. The fifth A lens group G5A is configured to be movable in a direction perpendicular to the optical axis. In the event of vibration of the zoom lens due to hand tremors or other reasons, the fifth A lens group is moved in a direction perpendicular to the optical axis to correct the image position, thereby correcting image jitter caused by the vibration.

[0426] The fifth lens group G5A is a cemented lens consisting of a positive meniscus lens L13 with its convex surface facing the image side and a biconcave lens L14, cemented sequentially from the object side. The fifth lens group G5B consists of a biconcave lens L15 and a positive meniscus lens L16 with its convex surface facing the object side, cemented sequentially from the object side.

[0427] The sixth lens group G6, starting from the object side, consists of a biconvex lens L17 and a cemented lens formed by cementing a biconcave lens L18 and a biconvex lens L19. The biconvex lens L17 is a glass-molded aspherical lens with an aspherical image-side surface.

[0428] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object side, the second lens group G2 first moves towards the image side and then towards the object side, the third lens group G3 moves towards the object side, the fourth lens group G4 moves towards the object side, the fifth lens group G5 moves towards the object side, and the sixth lens group G6 moves towards the object side. During zooming, the fourth lens group G4 and the sixth lens group G6 move along the same trajectory.

[0429] Focusing from an object at infinity toward a nearby object is achieved by moving the second lens group G2 toward the object side.

[0430] (2) Numerical Examples

[0431] Next, numerical examples of specific values ​​applicable to this zoom lens will be described. Table 43 shows the surface data of the zoom lens, and Table 44 shows the specifications of the zoom lens. Table 45 shows the variable spacing on the optical axis of the zoom lens when focusing at infinity, and Table 46 shows the variable spacing on the optical axis of the zoom lens when focusing towards a close object at a shooting distance (viewing distance) of 1m. Table 47 shows the focal lengths of each lens group constituting the zoom lens. Table 48 shows the aspherical coefficients of each aspherical surface. In addition, Table 50 shows the values ​​of conditional expressions (1) to (9). Furthermore, Table 52 shows the values ​​of each variable required to obtain the values ​​of conditional expressions (1) to (9). Figures 37-40 The diagrams show the longitudinal aberrations of the zoom lens in Embodiment 8 at the wide-angle end, the first intermediate focal length position, the second intermediate focal length position, and at infinity at the telephoto end.

[0432] [Table 43]

[0433]

[0434]

[0435]

[0436] [Table 44]

[0437]

[0438] [Table 45]

[0439] Variable interval [when focusing at infinity]

[0440]

[0441] [Table 46]

[0442] Variable interval [when focusing at a shooting distance of 1m]

[0443]

[0444] [Table 47]

[0445]

[0446] [Table 48]

[0447] Aspheric coefficient

[0448]

[0449] [Table 49]

[0450]

[0451] [Table 50]

[0452]

[0453] [Table 51]

[0454]

[0455]

[0456] [Table 52]

[0457]

[0458] (Industry availability)

[0459] According to the present invention, a zoom lens with abundant peripheral light, high optical performance, and a high zoom ratio can be provided, as well as an imaging device having the zoom lens. This zoom lens is suitable for interchangeable lenses in imaging devices employing interchangeable lens systems, such as SLR cameras and mirrorless cameras. The zoom lens achieves, for example, a wide angle of view of approximately 40 degrees (half angle of view) and also has a specified back focal length at the wide-angle end, therefore, it is particularly suitable for interchangeable lenses in SLR cameras.

Claims

1. A zoom lens comprising, 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 positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group, and the interval on the optical axis of adjacent lens groups changes during zooming, the first lens group having one negative lens and two positive lenses, characterized in that at least the fourth lens group is moved on the optical axis in a manner that narrows the interval on the optical axis of the third lens group and the fourth lens group when zooming from the wide-angle end toward the telephoto end, and the zoom lens satisfies the following conditional expressions; 0.10 < f34w / |f5| < 0.60 (1) -0.35 < fw / f5iw < 0.2 (2) 4.0 < fl / fw < 9.0 (3) -6.0 < Cr2r / fw < -0.9 (7) wherein f34w is the combined focal length of the third lens group and the fourth lens group at the wide-angle end; f5 is the focal length of the fifth lens group; fw is the focal length of the zoom lens at the wide-angle end; f5iw is the combined focal length from the fifth lens group at the wide-angle end to the lens group disposed closest to the image side in the zoom lens; fl is the focal length of the first lens group; and Cr2r is the radius of curvature of the surface closest to the image side of the second lens group.

2. A zoom lens comprising, 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 positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group, and the interval on the optical axis of adjacent lens groups changes during zooming, the first lens group having one negative lens and two positive lenses, characterized in that at least the fourth lens group is moved on the optical axis in a manner that narrows the interval on the optical axis of the third lens group and the fourth lens group when zooming from the wide-angle end toward the telephoto end, and the zoom lens satisfies the following conditional expressions; 0.10 < f34w / |f5| < 0.60 (1) -0.203 < fw / f5iw < 0.2 (2) wherein f34w is the combined focal length of the third lens group and the fourth lens group at the wide-angle end; f5 is the focal length of the fifth lens group; fw is the focal length of the zoom lens at the wide-angle end; f5iw is the combined focal length from the fifth lens group at the wide-angle end to the lens group disposed closest to the image side in the zoom lens.

3. A zoom lens comprising, 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 positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group, and the interval on the optical axis of adjacent lens groups changes during zooming, characterized in that at least the fourth lens group is moved on the optical axis in a manner that narrows the interval on the optical axis of the third lens group and the fourth lens group when zooming from the wide-angle end toward the telephoto end. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ at least the fourth lens group is moved on the optical axis in a manner that narrows the interval on the optical axis of the third lens group and the fourth lens group as zooming from the wide-angle end toward the telephoto end, and the zoom lens satisfies the following conditional expression; 0.10 ≤ f34w / |f5| ≤ 0.314 …… (1) -0.35 ≤ fw / f5iw ≤ 0.2 …… (2) 0.04 ≤ |f2| / ft ≤ 0.21 …… (6) wherein, f34w: combined focal length of the third lens group and the fourth lens group at the wide-angle end; f5: focal length of the fifth lens group; fw: focal length of the zoom lens at the wide-angle end; f5iw: combined focal length from the fifth lens group at the wide-angle end to the lens group disposed closest to the image side in the zoom lens; f2: focal length of the second lens group; ft: focal length of the zoom lens at the telephoto end.

4. The zoom lens according to claim 2 or 3, characterized by satisfies the following conditional expression; 2.5 ≤ f1 / fw ≤ 9.0 …… (3) wherein, f1: focal length of the first lens group.

5. The zoom lens according to any one of claims 1 to 3, characterized by satisfies the following conditional expression; 4.0 ≤ T3w / Y ≤ 8.0 …… (4) wherein, T3w: distance on the optical axis from the surface closest to the object side of the third lens group at the wide-angle end to the image plane; Y: maximum image height at the wide-angle end.

6. The zoom lens according to any one of claims 1 to 3, characterized by satisfies the following conditional expression; -0.10 ≤ f345w / f6iw ≤ 0.70 …… (5) wherein, f345w: combined focal length from the third lens group to the fifth lens group at the wide-angle end; f6iw: combined focal length from the sixth lens group at the wide-angle end to the lens group disposed closest to the image side in the zoom lens.

7. The zoom lens according to any one of claims 1 to 3, wherein the sixth lens group has positive refractive power.

8. The zoom lens according to any one of claims 1 to 3, wherein the fifth lens group has, in order from the object side, a fifth A lens group having negative refractive power, and a fifth B lens group having positive refractive power or negative refractive power; the fifth A lens group is configured to be movable in a direction perpendicular to the optical axis.

9. The zoom lens according to any one of claims 1 to 3, wherein the fifth lens group has at least two positive lenses.

10. The zoom lens according to any one of claims 1 to 3, wherein at least either one of the third lens group and the fourth lens group has a positive lens closest to the object side.

11. The zoom lens according to any one of claims 1 to 3, wherein the fourth lens group and the sixth lens group are moved along the same trajectory upon zooming.

12. The zoom lens according to any one of claims 1 to 3, wherein the first lens group has one negative lens and two positive lenses, and satisfies the following conditional expression: 0.127 ≤ f345w / f6iw ≤ 0.70 …… (5) wherein, f345w: combined focal length from the third lens group to the fifth lens group at the wide-angle end; f6iw: the composite focal length from the sixth lens group at the wide angle end to the lens group disposed closest to the image side in the zoom lens.

13. An image pickup device, characterized by comprising: Possessing: The zoom lens according to any one of claims 1 to 12; and An image pickup element that converts an optical image formed by the zoom lens into an electric signal on the image side of the zoom lens.

Images