Zoom lens and imaging device

Abstract

To provide a zoom lens and an imaging apparatus which can be miniaturized as a whole while achieving a high variable magnification ratio.SOLUTION: A zoom lens comprises, in the order from an object side, a positive first lens group G1 and 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 positive sixth lens group G6. When zooming, the first lens group G1 is fixed in the optical axis direction, an interval between adjacent lens groups changes and a prescribed conditional expression is satisfied. An imaging apparatus includes the zoom lens and an imaging element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens and an imaging device, and more particularly to a zoom lens and an imaging device suitable for an imaging device using a solid-state imaging element (CCD, CMOS, etc.), such as a digital still camera or a digital video camera. [Background technology]

[0002] Conventionally, imaging devices using various solid-state imaging elements, such as video cameras, digital still cameras, single-lens reflex cameras, and mirrorless single-lens cameras, have been widely used. As these imaging devices become smaller, imaging lenses (optical systems) are also required to be further miniaturized, and zoom lenses are no exception. A zoom lens is a lens that can change its focal length depending on the distance to the subject, and is used as an imaging lens for various imaging devices, such as surveillance imaging devices, video cameras, digital still cameras, single-lens reflex cameras, and mirrorless single-lens cameras.

[0003] As such a zoom lens, for example, Patent Documents 1 to 3 disclose a six-group zoom lens having, in order from the object side, positive, negative, positive, positive, negative, positive refractive power. A zoom lens has a plurality of lens groups like this, and during zooming, the focal length is changed by changing the spacing between adjacent lens groups. For this reason, a zoom lens is required to be configured compactly as a whole while achieving a high zoom ratio. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-218290 A [Patent Document 2] JP 2017-116703 A [Patent Document 3] JP 2017-134104 A Summary of the Invention [Problem to be solved by the invention]

[0005] The zoom lenses disclosed in the above Patent Documents 1 and 2 are not sufficient in terms of achieving a high zoom ratio, and are also insufficient in terms of shortening the overall optical length. In addition, the zoom lens disclosed in the above Patent Document 3 achieves a high zoom ratio, but since all lens groups are moved in the optical axis direction during zooming, a mechanical mechanism is required to move each lens group. This makes the mechanical mechanism complicated, and is not sufficient in terms of reducing the size of the entire zoom lens including the lens barrel.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a zoom lens and an image pickup apparatus that can be configured to be compact overall while achieving a high zoom ratio. [Means for solving the problem]

[0007] In order to solve the above problems, the zoom lens of the present invention is composed of, 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 having positive refractive power, wherein the first lens group is fixed in the optical axis direction during zooming and the interval between adjacent lens groups changes, and wherein the zoom lens satisfies the following conditional expressions: 4.5 < b4t / b4w < 10.0 (1) however, b4t: The lateral magnification of the fourth lens group when focusing on infinity at the telephoto end b4w: The lateral magnification of the fourth lens group when focusing on infinity at the wide-angle end

[0008] In order to solve the above problem, an imaging device according to the present invention is characterized by including the above zoom lens and an imaging element that converts an optical image formed by the zoom lens into an electrical signal. Effect of the Invention

[0009] According to the present invention, it is possible to provide a zoom lens and an image pickup apparatus that can be configured to have a small overall size while realizing a high zoom ratio. [Brief description of the drawings]

[0010] [Figure 1] 1 is a lens cross-sectional view of a zoom lens according to Example 1 of the present invention, where the upper row shows the wide-angle end state, the middle row shows the intermediate focal length state, and the lower row shows the telephoto end state (the same applies to the following lens cross-sectional views). [Diagram 2] 3A to 3C are diagrams illustrating spherical aberration, astigmatism, and distortion of the zoom lens of Example 1 in the wide-angle end state. [Diagram 3] 3A to 3C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 1 in an intermediate focal length state. [Figure 4] 3A to 3C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 1 in the telephoto end state. [Diagram 5] FIG. 11 is a lens sectional view of a zoom lens according to a second embodiment of the present invention. [Figure 6] 6A to 6C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 2 in the wide-angle end state. [Figure 7] 6A to 6C are diagrams illustrating spherical aberration, astigmatism, and distortion aberration of the zoom lens of Example 2 in an intermediate focal length state. [Figure 8] 6A to 6C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 2 in the telephoto end state. [Figure 9] FIG. 11 is a lens sectional view of a zoom lens according to a third embodiment of the present invention. [Figure 10] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 3 in the wide-angle end state. [Figure 11] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 3 in an intermediate focal length state. [Figure 12] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 3 in the telephoto end state. [Figure 13]FIG. 11 is a lens sectional view of a zoom lens according to a fourth embodiment of the present invention. [Figure 14] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 4 in the wide-angle end state. [Figure 15] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 4 in the intermediate focal length state. [Figure 16] 11A to 11C are diagrams showing spherical aberration, astigmatism, and distortion of the zoom lens of Example 4 in the telephoto end state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the zoom lens and the imaging device according to the present invention will be described. However, the zoom lens and the imaging device described below are one aspect of the zoom lens and the imaging device according to the present invention, and the zoom lens and the imaging device according to the present invention are not limited to the following aspects.

[0012] 1. Zoom Lens 1-1.Optical configuration First, the optical configuration of the zoom lens will be described. The zoom lens is composed of, 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 having positive refractive power, and zooming is performed by changing the spacing between adjacent lens groups.

[0013] By adopting such a power arrangement, the following effects can be obtained: First, in the zoom lens, a first lens group having positive refractive power is arranged closest to the object, and a second lens group having negative refractive power is arranged on its image side, and the distance between the first lens group and the second lens group is changed when zooming from the wide-angle end to the telephoto end, resulting in a telephoto type refractive power arrangement that can shorten the overall optical length compared to the focal length while achieving a high zoom ratio.

[0014] In addition, by adopting this power arrangement, an on-axis light beam close to the effective diameter is incident on the third lens group, so that it becomes easy to correct spherical aberration well in the third lens group. Furthermore, by providing positive refractive power in the fourth lens group and negative refractive power in the fifth lens group, respectively, and changing the distance between the fourth lens group and the fifth lens group during zooming, a configuration that easily realizes a high zoom ratio can be achieved. Furthermore, by providing positive refractive power in the sixth lens group closest to the image side, it becomes possible for the sixth lens group to effectively correct the curvature of field that changes throughout the entire zooming range.

[0015] A preferred configuration for each lens group will be described below. In this zoom lens, a lens group is composed of one or more lenses, and the spacing between adjacent lens groups changes during zooming, but the spacing between lenses included in a lens group does not change.

[0016] (1) First lens group The specific lens configuration of the first lens group is not particularly limited as long as it has a positive refractive power. In order to realize a zoom lens with a smaller telephoto ratio at the telephoto end, it is preferable to arrange the first lens group with a strong positive refractive power. In this case, by configuring the first lens group to include at least two positive lenses, it is possible to realize a zoom lens with a small telephoto ratio while suppressing the occurrence of various aberrations such as spherical aberration, which is preferable. In addition, by configuring the first lens group to include at least one negative lens, it is possible to effectively correct various aberrations, which is preferable.

[0017] (2) Second lens group The specific lens configuration of the second lens group is not particularly limited as long as it has negative refractive power. In order to realize a zoom lens with a smaller telephoto ratio at the telephoto end, it is preferable to arrange the second lens group with a strong negative refractive power. In this case, by configuring the second lens group to include at least two negative lenses, it is possible to realize a zoom lens with a small telephoto ratio while suppressing the occurrence of various aberrations, which is preferable. In addition, by configuring the second lens group to include at least one positive lens, it is possible to effectively correct various aberrations. In addition, it is preferable that at least one of the lenses constituting the second lens group has an aspheric surface in order to obtain a zoom lens with high optical performance while miniaturizing the zoom lens.

[0018] (3) Third lens group The third lens group is not particularly limited in its specific lens configuration as long as it has a positive refractive power, but in order to realize a compact zoom lens, it is preferable that the third lens group is composed of one single lens unit. Here, the single lens unit refers to a unit composed of one single lens or a cemented lens in which two or more single lenses are cemented together, and the single lens unit does not include an air gap. By constructing the third lens group from one single lens unit, it is possible to achieve a compact and lightweight zoom lens. In this case, it is more preferable that the single lens unit is composed of one single lens.

[0019] In order to obtain a zoom lens with high optical performance, it is preferable that the third lens group is configured to include at least one aspherical surface. For example, if the third lens group is configured with one positive lens having at least one aspherical surface, it is easy to obtain a zoom lens that is small in size and has high optical performance.

[0020] (4) Fourth lens group The fourth lens group is not particularly limited in its specific lens configuration as long as it has a positive refractive power, but in order to realize a zoom lens with high optical performance while realizing a compact zoom lens, it is preferable that the fourth lens group is composed of two single lens units. By configuring the fourth lens group with two single lens units, various aberrations can be corrected well. In particular, spherical aberration and axial chromatic aberration can be corrected well.

[0021] (5) Fifth lens group There are no particular limitations on the specific lens configuration of the fifth lens group as long as it has negative refractive power, but in order to realize a zoom lens with high optical performance while realizing a compact zoom lens, it is preferable that the fifth lens group be composed of two or less single lens units, and it is more preferable that it be composed of one single lens unit.

[0022] (6) Sixth lens group There are no particular limitations on the specific lens configuration of the sixth lens group as long as it has positive refractive power; however, in order to realize a zoom lens with high optical performance while realizing a compact zoom lens, it is preferable that the sixth lens group be composed of two or less single lens units, and it is more preferable that it be composed of one single lens unit.

[0023] (7) Aperture diaphragm In the zoom lens, the arrangement of the aperture diaphragm is not particularly limited. However, the aperture diaphragm here refers to the aperture diaphragm that determines the Fno of the zoom lens. For example, it is preferable to arrange the aperture diaphragm closer to the image side than the second lens group. In the case of a six-group zoom lens having a refractive power arrangement of positive, negative, positive, negative, positive in order from the object side as described above, it is preferable that an optical diaphragm is arranged adjacent to the object side or image side of the third lens group, or that an optical diaphragm is present within the third lens group.

[0024] 1-2.Operation (1)Zooming In this zoom lens, zooming is performed by changing the spacing between adjacent lens groups. In this case, the first lens group is fixed in the optical axis direction. In this zoom lens, the first lens group is often composed of lenses with a larger effective diameter than the other lens groups, and therefore the first lens group is larger and heavier than the other lens groups. Therefore, by making the first lens group a fixed group, the zoom lens does not need to have a mechanical mechanism (zoom mechanism) for moving the first lens group in the optical axis direction, and the mechanical mechanism can be simplified. Therefore, the zoom lens can be made smaller and lighter overall, including the lens barrel portion.

[0025] In this zoom lens, as long as the first lens group is a fixed group, the presence or absence, the direction of movement, and the amount of movement of the lens groups other than the first lens group are not particularly limited. All the lens groups other than the first lens group may be moved in the optical axis direction during zooming, or one or more of the lens groups may be fixed in the optical axis direction during zooming. In this zoom lens, in order to realize a small-sized zoom lens with a simple mechanical structure, it is preferable to change the intervals between the lens groups so that the interval between the first lens group and the second lens group becomes wider, the interval between the second lens group and the third lens group becomes narrower, and the interval between the third lens group and the fourth lens group becomes narrower during zooming from the wide-angle end to the telephoto end. Note that the intervals between the fourth lens group and the fifth lens group, and the intervals between the fifth lens group and the sixth lens group are not particularly limited. It is preferable to set the presence or absence, the direction of movement, and the amount of movement of each lens group so that the intervals between the lens groups change in this way.

[0026] For example, by making the third lens group or the sixth lens group, or both, fixed groups, it is possible to realize a zoom lens with a high zoom ratio and excellent optical performance while further simplifying the mechanical structure, and to make the zoom lens even more compact and lightweight overall.

[0027] (2) Focusing In the zoom lens, one or more of the first to sixth lens groups or a part of one of the lens groups is a focus group, and the focus group can be moved in the optical axis direction during focusing. Any lens group may be the focus group, but in the zoom lens, it is particularly preferable to use the fifth lens group as the focus group and move the fifth lens group in the optical axis direction to focus. In the zoom lens, the fifth lens group can be composed of a lens with a small diameter, so that the focus group can be made small and lightweight. Therefore, the actuator for moving the focus group can be made small. Therefore, the mechanical mechanism of the zoom lens can be further simplified, and the zoom lens can be made smaller and lighter overall.

[0028] 1-2.Conditional Expressions Various conditional expressions that the zoom lens preferably satisfies will be described below.

[0029] 1-2-1.Conditional expression (1) 4.5 < b4t / b4w < 10.0 (1) however, b4t: Lateral magnification of the 4th lens group when focusing on infinity at the telephoto end b4w: Lateral magnification of the 4th lens group when focusing on infinity at the wide-angle end

[0030] Conditional formula (1) defines the ratio between the lateral magnification of the fourth lens group when focusing on infinity at the telephoto end and the lateral magnification of the fourth lens group when focusing on infinity at the wide-angle end. By satisfying conditional formula (1), the ratio of the lateral magnifications of the fourth lens group falls within an appropriate range, making it easy to achieve a high zoom ratio while also making the zoom lens more compact.

[0031] On the other hand, when the value of conditional formula (1) is equal to or less than the lower limit, the lateral magnification ratio of the fourth lens group becomes small, making it difficult to achieve a high zoom ratio. On the other hand, when the value of conditional formula (1) is equal to or greater than the upper limit, the lateral magnification ratio of the fourth lens group becomes large, increasing the amount of movement of the fourth lens group during zooming. This increases the overall optical length, which is undesirable from the perspective of making the zoom lens compact.

[0032] In order to obtain the above effects, the lower limit of conditional formula (1) is more preferably 4.60, and even more preferably 4.70. The upper limit of conditional formula (1) is more preferably 9.00, and even more preferably 8.00. When these preferable lower and upper limits are adopted, the inequality sign (<) in conditional formula (1) may be replaced with an inequality sign with an equal sign (≦). The same principle applies to other conditional formulas.

[0033] 1-2-2.Conditional expression (2) 0.0 < L1 / f1 < 1.0 (2) however, L1: Lens length of the first lens group f1: focal length of the first lens group

[0034] Conditional formula (2) defines the ratio between the lens length of the first lens group and the focal length of the first lens group. By satisfying conditional formula (2), it is possible to provide the first lens group with a positive refractive power of an appropriate magnitude required to achieve a high zoom ratio, while preventing the lens length of the first lens group from becoming too long, and thus it is easy to achieve a high zoom ratio and a compact zoom lens.

[0035] On the other hand, when the value of conditional expression (2) is equal to or greater than the upper limit, the lens configuration length becomes long relative to the focal length of the first lens group, making it difficult to reduce the size of the zoom lens.

[0036] Since the first lens group has a positive refractive power, the value of conditional expression (2) will not be equal to or smaller than the lower limit. The smaller the value of conditional expression (2), the stronger the positive refractive power is disposed in the first lens group, and the shorter the lens construction length becomes. However, if the positive refractive power disposed in the first lens group becomes too strong, it may become difficult to correct various aberrations such as spherical aberration. From this viewpoint, the lower limit is preferably 0.10, and more preferably 0.20. On the other hand, in order to reduce the size of the zoom lens, the upper limit is more preferably 0.60, and more preferably 0.40.

[0037] 1-2-3.Conditional expression (3) 2.2 < |M2 / f2| < 4.0 (3) however, M2: Amount of movement of the second lens group on the optical axis when zooming from the wide-angle end to the telephoto end f2: focal length of the second lens group

[0038] Conditional formula (3) defines the ratio between the amount of movement of the second lens group on the optical axis during zooming from the wide-angle end to the telephoto end and the focal length of the second lens group. By satisfying conditional formula (3), it is possible to keep the amount of movement of the second lens group during zooming within an appropriate range while providing the second lens group with an appropriate negative refractive power required to achieve a high zoom ratio, and it becomes easy to achieve a compact zoom lens while achieving a high zoom ratio.

[0039] Here, the amount of movement of the second lens group on the optical axis when zooming from the wide-angle end to the telephoto end refers to the difference (mm) between the axial position of the second lens group at the wide-angle end and the axial position of the second lens group at the telephoto end.

[0040] On the other hand, when the value of conditional expression (3) is equal to or less than the lower limit, the amount of movement of the second lens group during zooming becomes small, making it difficult to obtain a high zoom ratio. On the other hand, when the value of conditional expression (3) is equal to or greater than the upper limit, the amount of movement of the second lens group during zooming becomes large. In this case, the total optical length becomes long, which is undesirable from the viewpoint of miniaturizing the zoom lens.

[0041] In order to obtain the above-mentioned effects, the lower limit of conditional formula (3) is more preferably 2.30, and even more preferably 2.40, and the upper limit of conditional formula (3) is more preferably 3.50, and even more preferably 3.00.

[0042] 1-2-4.Conditional expression (4) 0.70 < f3 / ft < 1.5 (4) however, f3: focal length of the third lens group ft: focal length of the zoom lens at the telephoto end

[0043] Conditional expression (4) defines the ratio between the focal length of the third lens group and the focal length of the zoom lens at the telephoto end (total system focal length). By satisfying conditional expression (4), the refractive power of the third lens group falls within an appropriate range, and the zoom lens can be kept compact while properly correcting various aberrations such as spherical aberration and curvature of field.

[0044] On the other hand, when the value of conditional expression (4) is equal to or less than the lower limit, the refractive power of the third lens group relative to the total focal length at the telephoto end becomes large, making it difficult to correct spherical aberration and curvature of field. On the other hand, when the value of conditional expression (4) is equal to or greater than the upper limit, the refractive power of the third lens group relative to the total focal length of the zoom lens becomes small. As a result, the distance between the third and fourth lens groups increases, making the total optical length of the zoom lens longer. This makes it difficult to reduce the size of the zoom lens.

[0045] In order to obtain the above-mentioned effects, the lower limit of condition (4) is more preferably 0.75, and even more preferably 0.80, and the upper limit of condition (4) is more preferably 1.25, and even more preferably 1.00.

[0046] 1-2-5.Conditional expression (5) 0.7 < |b4t×b5t×b6t| < 2.0 (5) however, b5t: Lateral magnification of the fifth lens group when focusing on infinity at the telephoto end b6t: Lateral magnification of the sixth lens group when focusing on infinity at the telephoto end

[0047] Conditional formula (5) defines the product of the lateral magnifications of the fourth, fifth, and sixth lens groups when focusing on infinity at the telephoto end. By satisfying conditional formula (5), the combined lateral magnification of the fourth, fifth, and sixth lens groups becomes an appropriate value, making it easy to achieve a high zoom ratio and a compact zoom lens.

[0048] On the other hand, when the value of conditional expression (5) is equal to or less than the lower limit, the value of the composite lateral magnification is small, making it difficult to realize a high zoom ratio. On the other hand, when the value of conditional expression (5) is equal to or greater than the upper limit, in order to realize a high zoom ratio, the amount of movement of the lens groups after the fourth lens group during zooming must be increased, and the total optical length becomes long. This makes it difficult to achieve a compact zoom lens.

[0049] In order to obtain these effects, the lower limit of condition (5) should more preferably be 0.80, and even more preferably be 0.90, and the upper limit of condition (5) should more preferably be 1.70, and even more preferably be 1.40.

[0050] 1-2-6.Conditional expression (6) 1.88 < Ndmax (6) however, Ndmax: The refractive index at the d line of the glass material with the highest refractive index among the lenses that make up the zoom lens.

[0051] Conditional formula (6) specifies the refractive index at the d-line of the glass material having the highest refractive index among the lenses constituting the zoom lens. A lens made of a glass material satisfying conditional formula (6) has a high refractive index, so that the curvature of the lens surface can be made gentle, and the occurrence of spherical aberration can be suppressed. Furthermore, a lens made of a glass material satisfying conditional formula (6) has a high refractive index, so that it can be made thinner than a lens made of a glass material having a low refractive index. These factors make it easier to configure a compact zoom lens with high optical performance while obtaining a high zoom ratio.

[0052] On the other hand, if conditional expression (6) is not satisfied, all of the lenses constituting the zoom lens are made of glass materials with refractive indices equal to or lower than the lower limit value stipulated in conditional expression (6). Therefore, in order to achieve a high zoom ratio, it is necessary to use thick lenses. In addition, glass materials with low refractive indices cannot be made to have a gentle spherical surface, and it is necessary to increase the number of lenses in order to correct various aberrations caused by the lens surface shape. For these reasons, if an attempt is made to obtain a zoom lens with high optical performance while obtaining a high zoom ratio, the total optical length becomes long, making it difficult to achieve a compact design.

[0053] In order to obtain these effects, the lower limit of the above conditional formula (6) should more preferably be 1.93, and even more preferably be 1.96.

[0054] 1-2-7.Conditional Expression (7) 1.0 < |f4 / f2| < 2.5 (7) however, f2: focal length of the second lens group f4: focal length of the fourth lens group

[0055] Conditional expression (7) defines the ratio of the focal length of the fourth lens group to the focal length of the second lens group. By satisfying conditional expression (7), the ratio of the refractive power of the second lens group to the refractive power of the fourth lens group falls within an appropriate range, making it easier to configure a compact zoom lens with high optical performance while achieving a high zoom ratio.

[0056] On the other hand, when the value of conditional expression (7) is equal to or less than the lower limit, the focal length of the fourth lens group becomes short, and the refractive power of the fourth lens group becomes too strong relative to the refractive power of the second lens group. In this case, it becomes difficult to correct various aberrations such as spherical aberration, and the number of lenses must be increased to obtain a zoom lens with high optical performance, making it difficult to reduce the size or improve the performance of the zoom lens. On the other hand, when the value of conditional expression (7) is equal to or more than the upper limit, the refractive power of the fourth lens group becomes too small. Therefore, in order to realize a high zoom ratio, the amount of movement of the fourth lens group during zooming must be increased, and the total optical length becomes long. Therefore, this is not preferable in terms of reducing the size of the zoom lens.

[0057] In order to obtain these effects, the lower limit of condition (7) should preferably be 1.30, and more preferably be 1.70, and the upper limit of condition (7) should preferably be 2.20, and even more preferably be 2.00.

[0058] 1-2-8.Conditional expression (8) 0.7 < |M4 / f4| < 1.0 (8) however, M4: Amount of movement of the fourth lens group on the optical axis when zooming from the wide-angle end to the telephoto end f4: focal length of the fourth lens group

[0059] Conditional formula (8) defines the ratio between the amount of movement of the fourth lens group on the optical axis during zooming from the wide-angle end to the telephoto end and the focal length of the fourth lens group. By satisfying conditional formula (8), it is possible to keep the amount of movement of the fourth lens group during zooming within an appropriate range while allowing the fourth lens group to bear a relatively large zoom ratio, making it easy to achieve a compact zoom lens while still achieving a high zoom ratio. As with M2, M4 indicates the difference (mm) between the axial position of the fourth lens group at the wide-angle end and the axial position of the fourth lens group at the telephoto end.

[0060] On the other hand, when the value of conditional expression (8) is equal to or less than the lower limit, the amount of movement of the fourth lens group during zooming becomes small, making it difficult to obtain a high zoom ratio. On the other hand, when the value of conditional expression (8) is equal to or greater than the upper limit, the amount of movement of the fourth lens group during zooming becomes large. In this case, the total optical length becomes long, which is not desirable from the viewpoint of making the zoom lens compact.

[0061] In order to obtain these effects, the lower limit of condition (8) should more preferably be 0.75, and even more preferably be 0.80, and the upper limit of condition (8) should more preferably be 0.95, and even more preferably be 0.90.

[0062] 1-2-9.Conditional expression (9) 0.25 < |M4 / M2| < 1.0 (9) however, M4: Amount of movement of the fourth lens group on the optical axis when zooming from the wide-angle end to the telephoto end M2: Amount of movement of the second lens group on the optical axis when zooming from the wide-angle end to the telephoto end

[0063] Conditional formula (9) defines the ratio of the amount of movement on the optical axis between the fourth lens group and the third lens group during zooming from the wide-angle end to the telephoto end. By satisfying conditional formula (9), it becomes easier to realize a high zoom ratio while keeping the amount of movement of the second lens group and the fourth lens group during zooming within an appropriate range and preventing the overall optical length from increasing.

[0064] On the other hand, when the value of conditional expression (9) is equal to or less than the lower limit, the movement amount of the fourth lens group is too small, making it difficult to obtain a high zoom ratio, or the movement amount of the second lens group is too large, making it difficult to obtain a zoom lens with a short optical overall length. On the other hand, when the value of conditional expression (9) is equal to or more than the upper limit, the movement amount of the fourth lens group is too large, making it difficult to obtain a zoom lens with a short optical overall length, or the movement amount of the second lens group is too small, making it necessary to provide the second lens group with a strong negative refractive power to obtain a predetermined zoom ratio, making it difficult to configure a zoom lens with high optical performance in a small size.

[0065] In order to obtain these effects, it is more preferable that the lower limit of condition (9) be 0.35, and even more preferable that it be 0.45.The upper limit of condition (9) is more preferable that it be 0.80, and even more preferable that it be 0.70.

[0066] 2. Imaging device Next, an imaging device according to the present invention will be described. The imaging device according to the present invention is characterized by comprising the zoom lens according to the present invention and an imaging element that converts an optical image formed by the zoom lens into an electrical signal. The imaging element is preferably provided on the image side of the zoom lens.

[0067] Here, the imaging element is not particularly limited, and solid-state imaging elements such as a CCD (Charge Coupled Device) sensor and a CMOS (Complementary Metal Oxide Semiconductor) sensor can also be used. The imaging device according to the present invention is suitable for imaging devices using these solid-state imaging elements, such as digital cameras and video cameras. The imaging device can be applied to various imaging devices, such as single-lens reflex cameras, mirrorless single-lens cameras, digital still cameras, surveillance cameras, car-mounted cameras, and drone-mounted cameras. These imaging devices may be lens-interchangeable imaging devices, or lens-fixed imaging devices in which the lens is fixed to the housing. In particular, the zoom lens according to the present invention can ensure a back focus suitable for an interchangeable lens system. Therefore, it is suitable for imaging devices such as single-lens reflex cameras equipped with an optical finder, a phase difference sensor, and a reflex mirror for branching light to these sensors.

[0068] Moreover, the imaging device of the present invention preferably has an image processing section that electrically processes the captured image data acquired by the imaging element to change the shape of the captured image, and an image correction data storage section that stores image correction data, an image correction program, and the like used to process the captured image data in the image processing section. When the zoom lens is made compact, the captured image shape formed on the imaging surface is likely to be distorted. In this case, it is preferable that the image correction data storage section stores distortion correction data for correcting the distortion of the captured image shape in advance, and the image processing section corrects the distortion of the captured image shape using the distortion correction data stored in the image correction data storage section. According to such an imaging device, the zoom lens can be made even more compact, and a beautiful captured image can be obtained, while the entire imaging device can be made compact.

[0069] Furthermore, in the imaging device according to the present invention, it is preferable that the image correction data storage unit stores magnification chromatic aberration correction data in advance, and the image processing unit performs magnification chromatic aberration correction of the captured image using the magnification chromatic aberration correction data stored in the image correction data storage unit. By correcting the magnification chromatic aberration, i.e., color distortion aberration, with the image processing unit, it is possible to reduce the number of lenses constituting the zoom lens. Therefore, with such an imaging device, it is possible to further miniaturize the zoom lens, obtain a beautiful captured image, and miniaturize the entire imaging device.

[0070] Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples. EXAMPLES

[0071] (1) Optical configuration FIG. 1 is a cross-sectional view of a zoom lens according to a first embodiment of the present invention, in a wide-angle end state, a middle focal length state, and a telephoto end state, when focusing on infinity. The zoom lens is composed of, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power, and zooming is performed by changing the interval between adjacent lens groups. An aperture stop S is disposed on the object side of the third lens group G3. The specific lens configuration of each lens group is as shown in FIG. 1. As shown in the figure, in the zoom lens, the third lens group G3 is composed of one single lens unit (one single lens), and the fourth lens group G4 is composed of two single lens units (a positive lens disposed in order from the object side, and a cemented lens in which a negative lens and a positive lens are cemented together).

[0072] Furthermore, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed in the optical axis direction, the second lens group G2 moves toward the image side, the third lens group G3 is fixed in the optical axis direction, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves in a convex path toward the object side, and the sixth lens group G6 is fixed in the optical axis direction.

[0073] In Fig. 1, "IMG" denotes an image plane, and specifically indicates the imaging plane of a solid-state imaging element such as a CCD sensor or a CMOS sensor, or the film plane of a silver halide film. Also, a cover glass CG or the like is provided on the object side of the image plane IMG. This point is the same in the lens cross-sectional views shown in the other embodiments, so the explanation will be omitted hereafter.

[0074] (2) Numerical examples Next, a numerical example to which the specific numerical values ​​of the zoom lens are applied will be described. The surface data, specifications, and aspherical data of the zoom lens are shown below. In the table showing the surface data, "No." indicates the order of the lens surface counted from the object side (surface number), "R" indicates the radius of curvature of the lens surface, "D" indicates the distance on the optical axis of the lens surface, "Nd" indicates the refractive index for the d-line (wavelength λ=587.6 nm), and "ABV" indicates the Abbe number for the d-line. In the "No." column, "ASPH" displayed in the column next to the surface number indicates that the lens surface is aspherical, and "STOP" indicates the aperture stop. In the "D" column, "D(○○)" (D(7) in this embodiment, etc.) indicates a variable distance during zooming. In each table shown below, the unit of length is all "mm", and the unit of angle of view is all "°". In the "radius of curvature" column, "0.0000" indicates a flat surface.

[0075] In the table showing the specifications, "f" is the focal length of the zoom lens, "Fno" is the F-number, and "W" is the half angle of view. Also, D(○○) is the variable interval during zooming, and from the left, it shows the values ​​for the wide-angle end state, the mid-focal length state, and the telephoto end state.

[0076] The table showing the aspheric data shows the aspheric coefficients when the aspheric shape is defined by the following formula. In the table, however, "E±a" is an exponential notation and "×10 ±a In the formula below, "Z" is the amount of displacement from the reference plane in the optical axis direction, "r" is the paraxial radius of curvature, "h" is the height from the optical axis in the direction perpendicular to the optical axis, "k" is the conic coefficient, and "An" is the n-th order aspheric coefficient.

[0077]

number

[0078] Furthermore, Table 1 below shows the values ​​of the conditional expressions (1) to (9), and Table 2 below shows the focal lengths of the lens groups and the values ​​of the elements required to calculate the conditional expressions (1) to (9), along with other examples.

[0079] (Driver) When. RD And ABV 1 49.0648 1.0000 1.85505 23.78 2 22.5495 4.5117 1.55206 75.50 3 65.0916 0.1500 4 34.9485 2.4440 1.66650 54.92 5 60.7735 0.1500 6 25.1764 3.1317 1.88622 40.14 7 77.4914 D( 7) 8ASPH 500.0000 0.2000 1.53920 41.21 9 104.8965 0.7000 2.00912 29.13 10 7.6401 3.4188 11 -16.3728 0.7000 1.88622 40.14 12 29.7033 0.1500 13 24.5591 2.5420 1.94887 18.14 14 -20.3927 0.2372 15 -18.7422 0.7000 1.88622 40.14 16 -55.2633 D(16) 17STOP 0.0000 1.0000 18ASPH 30.9719 1.6148 1.60013 40.57 19ASPH -200.0000 D(19) 20ASPH 8.5176 3.6780 1.59197 66.61 21ASPH -37.3017 0.2963 22 22.0057 0.6000 1.83930 37.34 23 5.5802 4.0849 1.49845 81.61 24 -15.8777 D(24) 25 17.9728 0.7000 1.86225 41.27 26 5.9965 D(26) 27 45.7680 0.7000 1.96073 32.32 28 13.8251 0.1500 29ASPH 13.5565 3.5987 1.49856 81.56 30ASPH -8.5859 2.0000 31 0.0000 1.0000 1.51872 64.20 32 0.0000 1.0000

[0080] (Specifications) F 5.3005 16.3192 50.3646 Fno 3.4926 5.0230 5.6419 W 40.9536 15.4817 5.1042 D(7) 0.6000 9.3749 17.1879 D(16) 17.8289 9.0541 1.2410 D(19) 10.2323 3.2722 0.3000 D(24) 2.5320 2.9072 5.9568 D(26) 2.8485 9.4334 9.3561

[0081] (aspheric data) No. K A4 A6 A8 A10 8 -1.19997E+00 1.70107E-04 -2.13956E-06 2.26579E-08 -1.14383E-10 18 -1.90134E-01 -4.33894E-04 -3.99250E-06 -2.39674E-07 1.27653E-08 19 -1.00001E+00 -4.26351E-04 -3.94808E-06 -1.25401E-07 5.84135E-09 20 -4.90318E-01 2.48531E-05 3.17286E-06 -5.44717E-08 3.70195E-11 21 -3.22275E-01 3.77004E-04 8.17868E-07 -1.18156E-07 4.38031E-10 29 -8.56089E-01 6.12861E-04 -2.75992E-05 1.09716E-06 -4.26175E-09 30 -8.00923E-02 1.19395E-03 -3.54670E-05 9.04386E-08 3.14184E-08

[0082] 2 to 4 show longitudinal aberration diagrams of the zoom lens in the wide-angle end state, the intermediate focal length state, and the telephoto end state. In each longitudinal aberration diagram, from the left in the drawing, spherical aberration, astigmatism, and distortion aberration are shown. In the diagrams showing spherical aberration, the vertical axis shows the ratio to the open F-number (FNo), the horizontal axis shows defocus, the solid line shows spherical aberration at the d-line (wavelength λ=587.56 nm), the short dashed line shows spherical aberration at the C-line (wavelength λ=656.28 nm), and the long dashed line shows spherical aberration at the F-line (wavelength λ=486.13 nm). In the diagrams showing astigmatism, the vertical axis shows image height (Y), the horizontal axis shows defocus, the solid line shows aberration at the sagittal image plane (S) for the d-line, and the four-dot chain line shows aberration at the tangential image plane (T) for the d-line. In the diagrams showing distortion aberration, the vertical axis shows image height (Y), the horizontal axis shows distortion aberration in %, and the horizontal axis shows distortion aberration. The matters relating to these figures are the same as those in the longitudinal aberration diagrams shown in other embodiments, and therefore, description thereof will be omitted below. EXAMPLES

[0083] (1) Optical configuration FIG. 5 is a cross-sectional view of a zoom lens according to a second embodiment of the present invention at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state. The zoom lens is composed of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power, and zooming is performed by changing the interval between adjacent lens groups. An aperture stop S is disposed on the object side of the third lens group G3. The specific lens configuration of each lens group is as shown in FIG. 5. Also, as shown in the figure, in the zoom lens, the third lens group G3 is composed of one single lens unit (one single lens), and the fourth lens group G4 is composed of two single lens units (a positive lens disposed in order from the object side, and a cemented lens in which a negative lens and a positive lens are cemented together).

[0084] Furthermore, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed in the optical axis direction, the second lens group G2 moves toward the image side, the third lens group G3 is fixed in the optical axis direction, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves in a convex path toward the object side, and the sixth lens group G6 is fixed in the optical axis direction.

[0085] (2) Numerical examples Next, a numerical example in which specific numerical values ​​of the zoom lens are applied will be described. The surface data, specifications, and aspherical data of the zoom lens are shown below. Also, Figs. 6 to 8 show longitudinal aberration diagrams of the zoom lens in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0086] (surface data) No. RD Nd ABV 1 46.3640 1.0000 1.85505 23.78 2 22.7589 4.7587 1.55206 75.50 3 153.5508 0.1500 4 24.1233 3.4177 1.86711 41.29 5 72.1639 D( 5) 6ASPH 487.2063 0.2000 1.53920 41.21 7 100.5375 0.7000 2.00912 29.13 8 7.7148 3.4281 9 -16.9949 0.7000 1.88622 40.14 10 34.1689 0.1500 11 27.5989 2.4926 1.95770 17.99 12 -21.0133 0.3228 13 -17.1213 0.7000 1.88416 40.22 14 -45.0982 D(14) 15STOP 0.0000 1.0000 16ASPH 28.6112 1.6270 1.59558 41.57 17ASPH -200.0013 D(17) 18ASPH 8.7613 3.9869 1.59396 67.04 19ASPH -35.2204 0.3245 20 20.8944 0.6000 1.83930 37.34 21 5.6063 3.8233 1.49845 81.61 22 -16.7807 D(22) 23 22.6358 0.7000 1.87579 40.73 24 6.2344 D(24) 25 24.1323 0.7000 1.92730 35.27 26 10.1692 0.1500 27ASPH 10.7637 3.7642 1.49856 81.56 28ASPH -9.8826 2.0000 29 0.0000 1.0000 1.51872 64.20 30 0.0000 1.0000

[0087] (Specifications) F 5.3005 16.3190 50.3700 Fno 3.7175 5.0820 5.7829 W 41.8736 15.5270 5.1181 D(5) 0.5998 10.4793 18.5103 D(14) 19.0961 9.2170 1.1854 D(17) 10.0110 3.5222 0.3000 D(22) 2.2139 2.9533 6.3042 D(24) 3.1831 8.9324 8.8042

[0088] (aspheric data) No. K A4 A6 A8 A10 6 1.22128E+00 1.88342E-04 -2.81024E-06 3.33751E-08 -1.85714E-10 16 1.00053E+00 -3.67558E-04 7.34617E-07 -6.54917E-07 2.81829E-08 17 -1.05931E+00 -3.59325E-04 1.63616E-07 -4.48512E-07 1.61774E-08 18 -5.82040E-01 3.36855E-06 2.14974E-06 -4.64888E-08 -6.86047E-10 19 -3.36066E-01 3.16440E-04 -7.33969E-07 -9.19363E-08 -5.70067E-10 27 -7.99975E-01 5.21844E-04 -2.70649E-05 1.18013E-06 -3.02818E-08 28 -9.99981E-01 9.09366E-04 -6.07046E-05 2.10946E-06 -4.31911E-08 EXAMPLES

[0089] (1) Optical configuration 9 is a cross-sectional view of a zoom lens according to a third embodiment of the present invention, in a wide-angle end state, a middle focal length state, and a telephoto end state, when focusing on infinity. The zoom lens is composed of, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power, and zooming is performed by changing the interval between adjacent lens groups. An aperture stop S is disposed on the object side of the third lens group G3. The specific lens configuration of each lens group is as shown in FIG. 9. Also, as shown in the figure, in the zoom lens, the third lens group G3 is composed of one single lens unit (one single lens), and the fourth lens group G4 is composed of two single lens units (a positive lens disposed in order from the object side, and a cemented lens in which a negative lens and a positive lens are cemented together).

[0090] Furthermore, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed in the optical axis direction, the second lens group G2 moves toward the image side, the third lens group G3 is fixed in the optical axis direction, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves in a convex path toward the object side, and the sixth lens group G6 moves toward the image side.

[0091] (2) Numerical examples Next, a numerical example in which specific numerical values ​​of the zoom lens are applied will be described. The surface data, specifications, and aspherical data of the zoom lens are shown below. Also, Figs. 10 to 12 show longitudinal aberration diagrams of the zoom lens in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0092] (surface data) No. RD Nd ABV 1 45.4845 1.0000 1.85505 23.78 2 22.0044 5.1447 1.55206 75.50 3 141.7169 0.1500 4 23.4734 3.5473 1.88080 40.45 5 70.8482 D( 5) 6ASPH 353.6420 0.2000 1.53920 41.21 7 97.0255 0.7000 2.00912 29.13 8 7.5979 3.4709 9 -17.1657 0.7000 1.88622 40.14 10 30.9671 0.1500 11 24.8962 2.5214 1.95129 18.20 12 -21.3896 0.3095 13 -17.6345 0.7000 1.88622 40.14 14 -49.0001 D(14) 15STOP 0.0000 1.0000 16ASPH 29.9313 1.6137 1.58614 43.11 17ASPH -200.0000 D(17) 18ASPH 8.6368 3.9402 1.59318 64.09 19ASPH -38.9592 0.2823 20 22.0446 0.6000 1.83930 37.34 21 5.7203 3.8942 1.49845 81.61 22 -15.7034 D(22) 23 19.9905 0.7000 1.86381 41.20 24 6.3254 D(24) 25 31.3567 0.7000 1.96074 32.32 26 11.0479 0.1500 27ASPH 10.8727 3.7182 1.49856 81.56 28ASPH -9.9315 D(28) 29 0.0000 1.0000 1.51872 64.20 30 0.0000 1.0000

[0093] (Specifications) F 5.3003 16.3195 50.3675 Fno 3.6189 4.9164 5.7711 W 42.0821 15.5977 5.1669 D(5) 0.6000 10.2184 17.7565 D(14) 18.3614 8.7430 1.2049 D(17) 9.7798 3.6119 0.3000 D(22) 2.1141 2.9679 6.2392 D(24) 2.9522 8.7115 9.4073 D(28) 2.8000 2.3550 1.7000

[0094] (aspheric data) No. K A4 A6 A8 A10 6 -1.20575E+00 1.86777E-04 -2.89843E-06 3.35007E-08 -1.79553E-10 16 -6.36360E-01 -2.91605E-04 -1.18207E-06 -2.71563E-07 1.41775E-08 17 -1.00944E+00 -2.97061E-04 -8.60701E-07 -2.25643E-07 9.33022E-09 18 -5.80057E-01 1.03927E-05 1.68585E-06 -1.18777E-08 -1.11741E-09 19 -9.99986E-01 3.25276E-04 -1.28428E-06 -3.68069E-08 -1.50201E-09 27 -5.84583E-02 4.45736E-04 -4.16679E-05 1.96283E-06 -4.56547E-08 28 -9.99994E-01 9.27032E-04 -8.09988E-05 3.17162E-06 -6.06853E-08 EXAMPLES

[0095] (1) Optical configuration Fig. 13 is a cross-sectional view of a zoom lens according to a fourth embodiment of the present invention at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state. The zoom lens is composed of, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power, and zooms by changing the spacing between adjacent lens groups. An aperture stop S is disposed on the object side of the third lens group G3. The specific lens configuration of each lens group is as shown in Fig. 13. Also, as shown in the figure, in this zoom lens, the third lens group G3 is composed of one single lens unit (one single lens), and the fourth lens group G4 is composed of two single lens units (a positive lens arranged in order from the object side, and a cemented lens consisting of a negative lens and a positive lens cemented together).

[0096] Furthermore, when zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed in the optical axis direction, the second lens group G2 moves toward the image side, the third lens group G3 is fixed in the optical axis direction, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves in a convex path toward the object side, and the sixth lens group G6 is fixed in the optical axis direction.

[0097] (2) Numerical examples Next, a numerical example in which specific numerical values ​​of the zoom lens are applied will be described. The surface data, specifications, and aspherical data of the zoom lens are shown below. Also, Figs. 14 to 16 show longitudinal aberration diagrams of the zoom lens in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0098] (surface data) No. R D Nd ABV 1 52.4095 1.0000 1.85505 23.78 2 21.5839 5.8102 1.55206 75.50 3 61.6106 0.1500 4 37.9976 2.3530 1.71305 42.88 5 71.8793 0.1500 6 23.1435 3.3813 1.88622 40.14 7 74.4885 D( 7) 8ASPH 500.0000 0.2000 1.53920 41.21 9 109.3177 0.7000 2.00912 29.13 10 7.4637 3.2552 11 -16.6319 0.7000 1.88622 40.14 12 24.9375 0.1500 13 21.4205 2.5815 1.93654 18.46 14 -19.7280 0.1500 15 -22.0159 0.7000 1.88814 39.78 16 -102.9559 D(16) 17STOP 0.0000 1.0000 18ASPH 30.7940 1.6111 1.61361 38.48 19ASPH -200.0000 D(19) 20ASPH 8.3856 3.7569 1.58980 67.48 21ASPH -37.7425 0.2484 22 25.2770 0.6000 1.83930 37.34 23 5.6785 4.1820 1.49845 81.61 24 -15.3952 D(24) 25 14.5776 0.7000 1.86854 40.06 26 5.7211 D(26) 27 22.0844 0.7000 1.96073 32.32 28 11.3703 0.1500 29ASPH 17.9787 3.5708 1.49856 81.56 30ASPH -7.6528 2.0000 31 0.0000 1.0000 1.51872 64.20 32 0.0000 1.0000

[0099] (Specifications) F 5.3014 16.3204 50.3558 Fno 3.4932 5.0234 5.6409 W 39.8106 15.4117 5.1040 D(7) 0.6000 9.1748 16.5145 D(16) 17.2763 8.7015 1.3618 D(19) 10.5041 3.6109 0.3000 D(24) 2.5495 3.0056 5.7978 D(26) 2.9695 9.4067 9.9254

[0100] (aspheric data) No. K A4 A6 A8 A10 8 -1.20000E+00 1.79452E-04 -2.50505E-06 3.05146E-08 -1.69585E-10 18 8.07549E-01 -4.56720E-04 -5.71587E-06 3.70423E-08 4.83827E-09 19 -1.00000E+00 -4.49045E-04 -6.35000E-06 1.66930E-07 -2.14196E-09 20 -5.03237E-01 2.55686E-05 2.54106E-06 -5.44347E-08 -5.09201E-10 21 3.10116E-01 3.97830E-04 -1.33283E-08 -1.68804E-07 8.92013E-10 29 -6.69712E-01 1.16359E-03 -3.87142E-05 1.31280E-06 -4.84365E-09 30 1.05862E-01 2.02442E-03 -4.31315E-05 -4.09429E-07 5.18585E-08

[0101] [Table 1] Example 1 Example 2 Example 3 Example 4 (1)b4t / b4w 5.002 7.000 5.556 4.729 (2)L1 / f1 0.313 0.241 0.262 0.370 (3)|M2 / f2| 2.675 2.872 2.781 2.594 (4)f3 / ft 0.890 0.837 0.884 0.866 (5)|b4t×b5t×b6t| 1.086 1.118 1.152 1.023 (6)Ndmax 2.009 2.009 2.009 2.009 (7)|f4 / f2| 1.894 1.884 1.904 1.961 (8)|M4 / f4| 0.846 0.827 0.807 0.848 (9)|M4 / M2| 0.599 0.542 0.553 0.641

[0102] [Table 2] Element Example 1 Example 2 Example 3 Example 4 fw 5.3005 5.3005 5.3003 5.3014 ft 50.3646 50.3700 50.3675 50.3558 f1 36.4257 38.6589 37.4962 34.7147 f2 -6.2015 -6.2358 -6.1681 -6.1350 f3 44.8055 42.1393 44.5332 43.6045 f4 11.7469 11.7459 11.7456 12.0308 f5 -10.7268 -10.0244 -10.9727 -11.2554 f6 20.6617 22.0429 24.0208 18.4489 M2 16.5880 17.9103 17.1562 15.9145 M4 9.9323 9.7113 9.4801 10.2041 M5 6.5074 5.6210 5.3549 6.9557 M6 0.0000 0.0000 1.1002 0.0000 L1 11.3874 9.3264 9.8421 12.8444 b4w -0.1018 -0.0731 -0.0960 -0.1052 b5w 1.9043 2.0365 1.9989 1.8853 b6w 0.8496 0.8413 0.8353 0.8212 b4t -0.5090 -0.5116 -0.5333 -0.4975 b5t 2.5095 2.5955 2.4501 2.5017 b6t 0.8501 0.8419 0.8814 0.8219 [Industrial Applicability]

[0103] According to the present invention, it is possible to provide a zoom lens and an image pickup apparatus that can be configured to have a small overall size while achieving a high zoom ratio. [Explanation of symbols]

[0104] G1: First lens group G2: Second lens group G3: Third lens group G4: Fourth lens group G5: Fifth lens group G6: 6th lens group S Aperture CG ···Cover glass IMG...Image surface

Claims

1. The optical system is composed of, 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 having positive refractive power, During zooming, the first lens group is fixed in the optical axis direction, and the interval between adjacent lens groups is changed. A zoom lens characterized by satisfying the following conditional expressions: 4.5 < b4t / b4w < 10.0 (1) 0.0 < L1 / f1 < 0.60 (2) 0.7 < |b4t x b5t x b6t| < 2.0 ... (5) however, b4t: lateral magnification of the fourth lens group when focusing on infinity at the telephoto end b4w: lateral magnification of the fourth lens group when focusing on infinity at the wide-angle end L1: Lens length of the first lens group f1: focal length of the first lens group b5t: lateral magnification of the fifth lens group when focusing on infinity at the telephoto end b6t: lateral magnification of the sixth lens group when focusing on infinity at the telephoto end

2. The optical system is composed of, 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 having positive refractive power, During zooming, the first lens group is fixed in the optical axis direction, and the interval between the adjacent lens groups is changed. A zoom lens characterized by satisfying the following conditional expressions: 4.5 < b4t / b4w < 10.0 (1) 1.023 < |b4t x b5t x b6t| < 2.0 ... (5) however, b4t: lateral magnification of the fourth lens group when focused on infinity at the telephoto end b4w: lateral magnification of the fourth lens group when focusing on infinity at the wide-angle end b5t: lateral magnification of the fifth lens group when focusing on infinity at the telephoto end b6t: lateral magnification of the sixth lens group when focusing on infinity at the telephoto end

3. The optical system is composed of, 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 having positive refractive power, During zooming, the first lens group is fixed in the optical axis direction, and the interval between the adjacent lens groups is changed. A zoom lens characterized by satisfying the following conditional expressions: 4.5 < b4t / b4w < 10.0 (1) 1.70 < | f4 / f2 | < 2.5 (7) 0.7 < |M4 / f4 | < 1.0 (8) however, b4t: lateral magnification of the fourth lens group when focused on infinity at the telephoto end b4w: lateral magnification of the fourth lens group when focusing on infinity at the wide-angle end f2: the focal length of the second lens group f4: focal length of the fourth lens group M4: Amount of movement of the fourth lens group on the optical axis during zooming from the wide-angle end to the telephoto end f4: focal length of the fourth lens group

4. 4. The zoom lens according to claim 2, which satisfies the following condition: 0.0 < L1 / f1 < 1.0 (2) however, L1: Lens length of the first lens group f1: focal length of the first lens group

5. 4. The zoom lens according to claim 3, which satisfies the following condition: 0.7 < |b4t x b5t x b6t| < 2.0 ... (5) however, b5t: lateral magnification of the fifth lens group when focusing on infinity at the telephoto end b6t: lateral magnification of the sixth lens group when focusing on infinity at the telephoto end

6. 3. The zoom lens according to claim 1, which satisfies the following condition: 1.0 < | f4 / f2 | < 2.5 (7) however, f2: the focal length of the second lens group f4: focal length of the fourth lens group

7. 3. The zoom lens according to claim 1, which satisfies the following condition: 0.7 < |M4 / f4 | < 1.0 (8) however, M4: Amount of movement of the fourth lens group on the optical axis during zooming from the wide-angle end to the telephoto end f4: focal length of the fourth lens group

8. 8. The zoom lens according to claim 1, which satisfies the following condition: 2.2 < |M2 / f2 | < 4.0 (3) however, M2: Amount of movement of the second lens group on the optical axis during zooming from the wide-angle end to the telephoto end f2: the focal length of the second lens group

9. 9. The zoom lens according to claim 1, which satisfies the following condition: 0.70 < f3 / ft < 1.5 (4) however, f3: the focal length of the third lens group ft: focal length of the zoom lens at the telephoto end

10. 10. The zoom lens according to claim 1, which satisfies the following condition: 1.88 < Ndmax (6) however, Ndmax: the refractive index at the d line of the glass material with the highest refractive index among the lenses constituting the zoom lens

11. 11. The zoom lens according to claim 1, which satisfies the following condition: 0.25 < |M4 / M2 | < 1.0 (9) however, M4: Amount of movement of the fourth lens group on the optical axis during zooming from the wide-angle end to the telephoto end M2: Amount of movement of the second lens group on the optical axis during zooming from the wide-angle end to the telephoto end

12. 12. The zoom lens according to claim 1, wherein the third lens group is fixed in the optical axis direction during zooming.

13. 13. The zoom lens according to claim 1, wherein the sixth lens group is fixed in the optical axis direction during zooming.

14. 14. The zoom lens according to claim 1, wherein the fifth lens group is moved in the optical axis direction during focusing to achieve focusing.

15. 15. The zoom lens according to claim 1, wherein the third lens group is composed of one single lens unit.

16. 16. The zoom lens according to claim 1, wherein the fourth lens group is composed of two single lens units.

17. 17. An imaging apparatus comprising: the zoom lens according to claim 1; and an imaging element that converts an optical image formed by the zoom lens into an electrical signal.

Images