Zoom lens and imaging device

Abstract

The object of this invention is to provide a zoom lens and an imaging device having the zoom lens that are suitable for digital still cameras with a short flange back, are generally compact, allow for easy reduction of the diameter of the final lens group, and are high-performance. [Solution] To solve the above problems, the zoom lens according to the present invention is composed of a front group (G1~G6) having at least four lens groups in order from the object side and having a positive refractive power as a whole, and a lens group GB (G7) arranged on the image side of the front group, and magnification is achieved by changing the spacing between adjacent lens groups on the optical axis, and the lens group GB has lens components Nb (L19), Nf (L18), and P (L17) in order from the image side, and the positive lens component P has a biconvex shape, and focusing is performed by moving a part of the front group (G6) along the optical axis to satisfy a predetermined conditional equation.

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 imaging devices using solid-state image sensors (such as CCDs and CMOS sensors) such as digital still cameras and digital video cameras. [Background technology]

[0002] Conventional zoom lenses for single-lens reflex cameras (hereinafter referred to as "SLR cameras") required a long flange back distance regardless of focal length because optical elements related to the optical viewfinder, such as the reflex mirror, were located within the camera body. Therefore, the lens design of the rear lens group of the zoom lens, which is located on the image side, was such that a group of lenses with positive refractive power was used to easily secure the back focus and thus ensure the required flange back distance. However, in recent years, mirrorless cameras and digital still cameras (hereinafter referred to as "mirrorless cameras, etc.") that capture images using live view images displayed on an LCD screen located on the back of the imaging device have become widespread. Imaging devices that do not have an optical viewfinder do not need to have a reflex mirror, etc., located within the camera body. For such imaging devices that do not require a long flange back distance, there is a demand for zoom lenses with a short back focus.

[0003] Furthermore, conventionally, each pixel on the imaging surface of an image sensor is provided with a condensing lens, such as an on-chip microlens, to efficiently receive incident light. The light-receiving angle of on-chip microlenses is limited to a predetermined range, and conventionally, in order to efficiently receive incident light with on-chip microlenses, the exit pupil diameter of the imaging lens was made larger than a certain amount to reduce the inclination angle of the incident light with respect to the optical axis, so that the incident light beam was approximately parallel to the optical axis when it entered the imaging surface. In order to ensure such telecentricity, conventionally, a lens component with positive refractive power was placed in the image-side portion of the zoom lens.

[0004] However, in recent years, the aperture ratio of image sensors has improved, the light-receiving angle range of on-chip microlenses has expanded, and the optical performance of on-chip microlenses has also improved. As a result, the constraints on the position and size of the exit pupil required for zoom lenses have decreased, and even when a lens component with negative refractive power is placed on the image side of the zoom lens to configure light to be obliquely incident on the imaging surface, peripheral vignetting (shading) due to mismatch between the on-chip microlens and the exit pupil of the zoom lens has become less noticeable.

[0005] Therefore, in recent years, attempts have been made to miniaturize zoom lenses by placing a lens component with negative refractive power in the image-side portion of the zoom lens (see, for example, Patent Documents 1 to 3).

[0006] The zoom lens described in Patent Document 1 has a refractive force arrangement of positive, negative, positive, negative, negative, in order from the object side, and the negative lens group, which is positioned on the image side of the optical aperture among all the lens groups, is designated as the focusing group, thereby achieving miniaturization of the entire zoom lens unit.

[0007] However, in the zoom lenses of Examples 1, 2, 4, and 5 described in Patent Document 1, although a negative refractive power is placed in the final lens group to shorten the overall optical length, a lens component with a positive refractive power is placed on the image side of the final lens group, making it difficult to reduce the diameter of the final lens group. Therefore, when a zoom lens for an imaging device with a short flange back is required to shorten the overall optical length, the diameter of the final lens group becomes significantly larger, making it difficult to miniaturize in the radial direction.

[0008] Furthermore, in the zoom lenses of Examples 3, 6, 7, 8, and 9 described in Patent Document 1, a lens component with negative refractive power is placed on the image side of the final lens group, but the final lens group is fixed to the image plane when zooming from the wide-angle end to the telephoto end. As a result, the effective light beam diameter of the final lens group becomes larger at the telephoto end, making it difficult to reduce the diameter of the final lens group in this case as well. Moreover, the zoom lenses of Examples 6, 7, 8, and 9 described in Patent Document 1 have a narrow half-angle of view of about 11° at the wide-angle end, and do not achieve a sufficiently wide angle of view at the wide-angle end. On the other hand, the zoom lens of Example 3 described in Patent Document 1 has a wide half-angle of view of about 38.8° at the wide-angle end, but does not achieve a reduction in the overall optical length.

[0009] The zoom lens described in Patent Document 2 has a refractive force arrangement of positive, positive, negative, positive in order from the object side, and by satisfying a predetermined conditional equation, the entire zoom lens unit is made smaller. Furthermore, this zoom lens has a small F-number at the telephoto end, resulting in a bright zoom lens.

[0010] However, in the zoom lenses of Examples 1, 2, 3, and 4 described in Patent Document 2, a lens component with negative refractive power is placed on the image side of the final lens group. However, when zooming from the wide-angle end to the telephoto end, the final lens group is fixed relative to the image plane (Examples 1 and 2) or moves toward the image side (Examples 3 and 4), so the overall optical length at the wide-angle end cannot be shortened. In zoom lenses where the overall optical length changes between the wide-angle and telephoto ends, the lens barrel is generally configured as a nesting structure in which the inner barrel can be housed in the outer barrel, and the length of the lens barrel is extended when zooming from the wide-angle end to the telephoto end. Therefore, if the overall optical length at the wide-angle end is long, the overall length when the inner barrel is housed in the outer barrel becomes long. Furthermore, in the zoom lens of Example 5 described in Patent Document 2, the final lens group is composed of a convex lens and a concave lens in order from the object side, and an attempt has been made to suppress the increase in diameter of the final lens group by moving the final lens group toward the object side when zooming from the wide-angle end to the telephoto end. However, the refractive power of the convex lens constituting the final lens group is weak, and the distance between the convex lens and the concave lens on the optical axis is also wide, so the reduction in diameter of the final lens group is insufficient.

[0011] The zoom lens described in Patent Document 3 has a refractive force arrangement of positive, negative, positive, positive, negative in order from the object side, and by providing reflective members in the first lens group and the lens group located closest to the image, the thickness of the imaging device is reduced, thereby achieving miniaturization and improved performance of the entire zoom lens unit.

[0012] However, the zoom lenses described in Examples 1, 2, and 3 of Patent Document 3 all have a final lens group that includes at least a convex lens and a concave lens in order from the object side, and certain considerations have been made to suppress the increase in diameter of the final lens group. However, the zoom lenses described in Patent Document 3 perform focusing by moving the final lens group. Therefore, it is difficult to lighten the focusing lens group, and the actuators for AF (autofocus) drive become large, making it difficult to miniaturize the entire zoom lens unit. Furthermore, the BF (back focus) is not sufficiently short relative to the maximum image height of the image sensor's imaging plane. Moreover, since the first lens group and the final lens group are fixed relative to the image plane during zooming, there is no change in the overall optical length between the wide-angle end and the telephoto end, and a reduction in the overall optical length is required. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Japanese Patent Publication No. 2014-228807 [Patent Document 2] Japanese Patent Publication No. 2017-40875 [Patent Document 3] Japanese Patent Publication No. 2018-13684 [Overview of the project] [Problems that the invention aims to solve]

[0014] The problem addressed by the present invention has been viewed in view of the above-mentioned issues, and is to provide a zoom lens and an imaging device having the zoom lens that are suitable for imaging devices with a short flange back, are generally compact, allow for easy reduction of the diameter of the final lens group, and are high performance. [Means for solving the problem]

[0015] To solve the above problems, the zoom lens according to the present invention is composed of a front group having a positive refractive power as a whole, and a lens group GB arranged on the image side of the front group, in order from the object side, and is a zoom lens that changes magnification by changing the distance between adjacent lens groups on the optical axis, the front group has at least four lens groups, the front group has a negative lens group GF on the image side, and when single lenses or cemented lenses are referred to as lens components, the lens group GB has a negative lens component Nb, a negative lens component Nf, and a positive lens component P in order from the image side, the positive lens component P is biconvex, and focusing is performed by moving the negative lens group GF along the optical axis, satisfying the following conditional equation. (3-1) 0.3 ≤ BFw / Y ≤ 1.2 (7-1) 0.2 ≦ fNf / fNb ≦ 1.002 however, BFw: Back focus of the zoom lens at the wide-angle end. Y: Maximum image height of the zoom lens fNf: Focal length of the negative lens component Nf fNb: Focal length of the negative lens component Nb

[0016] Furthermore, in order to solve the above problems, the imaging device according to the present invention is characterized by comprising the zoom lens and an image sensor on the image plane side of the zoom lens that converts the optical image formed by the zoom lens into an electrical signal. [Effects of the Invention]

[0017] According to the present invention, a zoom lens and an imaging device having the zoom lens can be provided, which are suitable for a digital still camera with a short flange back, are small as a whole, are easy to reduce the diameter of the final lens group, and have high performance.

Brief Description of the Drawings

[0018] [Figure 1] The lens cross-sectional view at infinity focus at the wide-angle end of the zoom lens of Example 1 of the present invention is shown. [Figure 2] It is an aberration diagram at the wide-angle end of the zoom lens of Example 1. [Figure 3] It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 1. [Figure 4] It is an aberration diagram at the telephoto end of the zoom lens of Example 1. [Figure 5] The lens cross-sectional view at infinity focus at the wide-angle end of the zoom lens of Example 2 of the present invention is shown. [Figure 6] It is an aberration diagram at the wide-angle end of the zoom lens of Example 2. [Figure 7] It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 2. [Figure 8] It is an aberration diagram at the telephoto end of the zoom lens of Example 2. [Figure 9] The lens cross-sectional view at infinity focus at the wide-angle end of the zoom lens of Example 3 of the present invention is shown. [Figure 10] It is an aberration diagram at the wide-angle end of the zoom lens of Example 3. [Figure 11] It is an aberration diagram at the intermediate focal length position of the zoom lens of Example 3. [Figure 12] It is an aberration diagram at the telephoto end of the zoom lens of Example 3. [Figure 13] The lens cross-sectional view at infinity focus at the wide-angle end of the zoom lens of Example 4 of the present invention is shown. [Figure 14] It is an aberration diagram at the wide-angle end of the zoom lens of Example 4. [Figure 15]This is an aberration diagram of the zoom lens of Example 4 at an intermediate focal length position. [Figure 16] This is an aberration diagram of the zoom lens of Example 4 at its telephoto end. [Figure 17] This shows a cross-sectional view of the zoom lens of Embodiment 5 of the present invention when it is focused at infinity at the wide-angle end. [Figure 18] This is an aberration diagram of the zoom lens of Example 5 at its wide-angle end. [Figure 19] This is an aberration diagram of the zoom lens of Example 5 at an intermediate focal length position. [Figure 20] This is an aberration diagram of the zoom lens of Example 5 at the telephoto end when it is focused at infinity. [Figure 21] This shows a cross-sectional view of the zoom lens of Embodiment 6 of the present invention when it is focused at infinity at the wide-angle end. [Figure 22] This is an aberration diagram of the zoom lens of Example 6 at its wide-angle end. [Figure 23] This is an aberration diagram of the zoom lens of Example 6 at an intermediate focal length position. [Figure 24] This is an aberration diagram of the zoom lens of Example 6 at its telephoto end. [Figure 25] This shows a cross-sectional view of the zoom lens of Embodiment 7 of the present invention when it is focused at infinity at the wide-angle end. [Figure 26] This is an aberration diagram of the zoom lens of Example 7 at its wide-angle end. [Figure 27] This is an aberration diagram of the zoom lens of Example 7 at an intermediate focal length position. [Figure 28] This is an aberration diagram of the zoom lens of Example 7 at its telephoto end. [Figure 29] This shows a cross-sectional view of the zoom lens of Embodiment 8 of the present invention when it is focused at infinity at the wide-angle end. [Figure 30] This is an aberration diagram of the zoom lens of Example 8 at its wide-angle end. [Figure 31] This is an aberration diagram of the zoom lens of Example 8 at an intermediate focal length position. [Figure 32]This is an aberration diagram of the zoom lens of Example 8 at its telephoto end. [Figure 33] This shows a cross-sectional view of the zoom lens of Embodiment 9 of the present invention when it is focused at infinity at the wide-angle end. [Figure 34] This is an aberration diagram of the zoom lens of Example 9 at its wide-angle end. [Figure 35] This is an aberration diagram of the zoom lens of Example 9 at an intermediate focal length position. [Figure 36] This is an aberration diagram of the zoom lens of Example 9 at its telephoto end. [Modes for carrying out the invention]

[0019] The following describes embodiments of the zoom lens and imaging device according to the present invention. However, the zoom lens and imaging device described below are only 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 embodiments.

[0020] 1. Zoom lens 1-1. Optical configuration of a zoom lens The zoom lens of this embodiment is substantially composed of a front group having a positive refractive power as a whole, and a lens group GB positioned on the image side of the front group, in order from the object side. Here, "substantially composed" means that it is sufficient for the zoom lens to substantially consist of the above-mentioned front group and lens group GB as optical elements, and it is permissible to include other lens groups, or optical elements other than lenses such as an aperture or cover glass. Each lens group shall contain at least one lens.

[0021] The optical configuration of the lens group constituting the zoom lens according to the present invention will be described in detail below.

[0022] (1) Front group The front group has a positive refractive power as a whole, and as long as it has at least three lens groups, its specific group configuration is not particularly limited. By forming the front group with at least three lens groups and changing the distance between adjacent lens groups along the optical axis during zooming, it becomes easier to suppress aberration fluctuations by relatively moving each lens group during magnification. This increases the degree of freedom regarding the position of each lens group during magnification and the optical design, making it possible to obtain a zoom lens with high imaging performance.

[0023] The front group preferably comprises at least one lens group with positive refractive power and at least one lens group with negative refractive power. This configuration reduces the uneven distribution of the magnification burden on each lens group in the front group, allowing for good aberration correction with fewer lenses, and enabling the realization of a high magnification ratio and a compact zoom lens. Furthermore, the front group preferably comprises at least four lens groups. Constituting the front group with four or more lens groups increases the degree of freedom regarding the position of each lens group during magnification and optical design, which is preferable in terms of high magnification ratio and high performance.

[0024] The front group preferably includes a negative lens group GF on its image-side. By placing the negative lens group GF on the image-side of the front group, it becomes easier to create a refractive power configuration with a strong telephoto tendency for the zoom lens, and thus easier to reduce the overall length. Here, a refractive power configuration with a telephoto tendency means that the telephoto ratio (optical length / focal length) of the zoom lens is less than 1, and a strong telephoto tendency means that the telephoto ratio is a smaller value.

[0025] Furthermore, the lens group positioned closest to the object in the front group may have either a positive or negative refractive power. When the lens group positioned closest to the object in the front group has a positive refractive power, it is easier to achieve a high magnification ratio as a positive-group-first type zoom lens, and it becomes easier to realize a zoom lens with a strong telephoto tendency and a short optical length at the telephoto end. On the other hand, when the lens group positioned closest to the object in the front group has a negative refractive power, it is possible to obtain a zoom lens with a wide angle of view at the wide-angle end as a negative-group-first type zoom lens.

[0026] (2) Lens group GB Lens group GB is positioned on the image side of the front group, and is substantially the closest to the image in the zoom lens. Lens group GB may have a positive or negative refractive power as a whole. When lens group GB has a positive refractive power as a whole, it is easier to realize a bright lens with a small F-number. In this case, it is also easier to widen the angle, making it easier to realize a zoom lens with a wide angle of view at the wide-angle end.

[0027] On the other hand, if the lens group GB as a whole has a negative refractive power, it becomes easier to design the zoom lens with a refractive power configuration that favors telephoto imaging, making it easier to reduce the overall length. In this case, there is also the advantage that it is easier to reduce the diameter of the lens group (including lens group GB) located on the image side of the zoom lens.

[0028] The lens group GB has, in order from the image side, a negative lens component Nb, a negative lens component Nf, and a positive lens component P. As long as the lens group GB has these three lens components, the other lens configurations are not particularly limited. However, the lens component referred to here means a single lens or a lens unit such as a cemented lens formed by integrating multiple single lenses without an air gap. That is, even if a lens component has multiple optical surfaces, only its outermost object side and outermost image side are in contact with the air, and the other surfaces are not in contact with the air. Furthermore, in this specification, a single lens may be either a spherical lens or an aspherical lens. Furthermore, aspherical lenses also include so-called composite aspherical lenses in which an aspherical film is attached to the surface.

[0029] The lens group GB may have one or more lens components on the object side of the positive lens component P. By configuring the lens group GB to have at least a negative lens component Nb, a negative lens component Nf, and a positive lens component P in order from the image side, the exit pupil position of the zoom lens can be positioned closer to the image side, and the back focus can be shortened. Therefore, it becomes easier to shorten the overall optical length of the zoom lens and to reduce the diameter of the lens group GB.

[0030] The lens shapes of the negative lens components Nb and Nf, and the positive lens component P are not particularly limited, but they are preferably as follows.

[0031] It is preferable that the object side surface of the negative lens component Nb is concave. By making the object side surface of the negative lens component Nb concave, it becomes possible to effectively correct the under-field curvature and distortion aberration generated by the positive lens component P. Furthermore, it is even more preferable that the negative lens component Nb has a negative meniscus shape with a convex surface facing the image side. If the image side surface of the negative lens component Nb is concave, i.e., if the negative lens component Nb has a biconcave shape, the over-distortion aberration becomes too large, making it difficult to correct effectively.

[0032] The positive lens component P is preferably biconvex. By making the positive lens component P biconvex, it becomes easier to shorten the back focus, and the obliquely incident light rays at the wide-angle end can be efficiently refracted by this positive lens component P, thus enabling a reduction in the diameter of the lens group GB.

[0033] Furthermore, it is preferable that the air lens formed by the image side of the positive lens component P and the object side of the negative lens component Nf be concave. In particular, it is preferable that the air lens be biconcave or a negative meniscus shape with the concave surface facing the object. By making the air lens concave, that is, by making the air lens act as a convex lens, the balance of spherical aberration, field curvature, and distortion can be corrected well. On the other hand, if the air lens is convex, that is, if the air lens acts as a concave lens, the spherical aberration, field curvature, and distortion generated in the lens group GB become too large in the over-direction, making it difficult to correct them well.

[0034] 1-2.Operation (1) Zooming This zoom lens achieves magnification by changing the distance between adjacent lens groups along their optical axes. Specifically, it achieves magnification by changing the distance between each lens group in the front group along its optical axis, and the distance between the lens group closest to the image within the front group and lens group GB along its optical axis.

[0035] When zooming, the distance between each lens group in the front group along the optical axis should change. All lens groups may move along the optical axis, or some lens groups may be fixed in the direction of the optical axis.

[0036] While there are no particular limitations on whether or not each lens group moves, it is preferable that the lens group closest to the object in the front group moves along the optical axis during zooming. By moving the lens group closest to the object in the front group during magnification, the burden on each lens group during magnification is reduced, making it possible to obtain a zoom lens with high imaging performance while achieving a high magnification ratio.

[0037] The GB lens group is a single lens group, and during zooming, each lens component of the GB lens group moves in the same direction with the same amount of movement, and the spacing between each lens component of the GB lens group does not change during zooming.

[0038] When zooming from the wide-angle end to the telephoto end, it is preferable for the lens group GB to move toward the object. By moving the lens group GB toward the object, it becomes easier to shorten the back focus of the zoom lens at the wide-angle end, thereby shortening the overall optical length of the zoom lens at the wide-angle end. Furthermore, it becomes easier to reduce the effective light beam diameter of the lens group GB at the telephoto end, allowing for a reduction in the overall diameter of the lens group GB in the zoom lens unit.

[0039] (2) Focusing This zoom lens focuses by moving some of the lens groups that make up the front group along the optical axis. In this case, by designating a lens group consisting of two or fewer lens components as the focusing group, the focusing group can be made smaller and lighter compared to when the lens group GB is the focusing group. This enables rapid focusing while facilitating miniaturization of the entire zoom lens unit.

[0040] On the other hand, if the GB lens group is used as the focusing group, at least three lens components must be moved along the optical axis during focusing, making it difficult to miniaturize and lighten the focusing group, and thus making rapid focusing difficult. Furthermore, if the focusing group becomes large and heavy, the actuator (AF actuator) used to drive the focusing group during autofocus (AF) will also become larger, which is undesirable as it will increase the overall size of the zoom lens unit.

[0041] In order to reduce the size and weight of the focusing group, it is preferable to use the lens group other than the one positioned closest to the object among the lens groups that make up the front group as the focusing group. The lens group positioned closest to the object in the front group is generally large in diameter and heavy, and is therefore undesirable in the respect mentioned above.

[0042] In order to reduce the size and weight of the focusing group, it is preferable to place the negative lens group GF on the image side of the front group, make this negative lens group GF the focusing group, and move it toward the image side along the optical axis when focusing from infinity to close distance. When the lens group with negative refractive power is placed on the image side of the front group among all the lens groups that make up the zoom lens, the negative lens group GF can be easily reduced in diameter, thus making it easy to reduce the size and weight of the focusing group.

[0043] When employing a contrast AF system, the subject's position is detected by rapidly moving the focus group during focusing to detect the peak contrast position of the subject. This operation is called wobbling. When imaging while displaying the subject image on a liquid crystal display or the like in the imaging device, a large change in the angle of view during wobbling results in a large change in the angle of view of the displayed image. Since the negative lens group GF is located on the image side in the zoom lens, when employing a contrast AF system, the change in the angle of view associated with wobbling during AF drive can be reduced, and therefore the change in the angle of view of the displayed image can also be reduced. For this reason as well, it is preferable to use the negative lens group GF as the focus group.

[0044] 1-3. Conditional expression The zoom lens should, in addition to adopting the configuration described above, satisfy one or more of the following conditional equations.

[0045] 1-3-1. Conditional expression (1) (1) -0.7 ≦ (RNf+RNb) / (RNf-RNb) ≦ 2.0 however, RNf: Radius of curvature of the negative lens component Nf at the outermost image surface. RNb: Radius of curvature of the outermost surface of the object with respect to the negative lens component Nb.

[0046] The above conditional equation (1) defines the shape of the air lens formed by the image-side edge of the negative lens component Nf and the object-side edge of the negative lens component Nb. By satisfying conditional equation (1), field curvature can be well corrected throughout the entire zoom range, and a zoom lens with high imaging performance can be obtained. Note that when each lens component is composed of a single lens, the image-side edge refers to the image-side edge of that single lens, and the object-side edge refers to the object-side edge. When each lens component is composed of a cemented lens, the image-side edge refers to the image-side edge of the lens that is positioned furthest towards the image among the lenses that make up the cemented lens, and the object-side edge refers to the object-side edge of the lens that is positioned furthest towards the object among the lenses that make up the cemented lens.

[0047] Conversely, if the value of condition (1) falls below the lower limit, the divergence effect of the negative lens component Nb on the object side becomes weaker than that of the negative lens component Nf on the image side, making it difficult to adequately correct underexposed field curvature. On the other hand, if the value of condition (1) exceeds the upper limit, the divergence effect of the negative lens component Nb on the object side becomes too strong compared to that of the negative lens component Nf on the image side, making it difficult to adequately correct overexposed field curvature.

[0048] To obtain the above effect, the upper limit of conditional expression (1) is more preferably 1.8, even more preferably 1.6, and even more preferably 1.4. Furthermore, the lower limit of conditional expression (1) is more preferably -0.6, even more preferably -0.5, and even more preferably -0.4.

[0049] 1-3-2. Conditional expression (2) The zoom lens preferably includes a negative lens group GF on the image side of the front group and satisfies the following condition. (2) 1.1 ≦ βFBt / βFBw ≦ 2.5 however, βFBt: Combined horizontal magnification of lens group GF and lens group GB at the telephoto end. βFBw: Combined horizontal magnification of lens group GF and lens group GB at the wide-angle end.

[0050] Conditional equation (2) defines the ratio of the combined horizontal magnification at the wide-angle end to the combined horizontal magnification at the telephoto end, which is determined by the lens group GF positioned closest to the image in the zoom lens and the lens group GB positioned on the image side of lens group GF. By satisfying conditional equation (2), it is possible to shorten the overall optical length of the zoom lens at the telephoto end while maintaining high imaging performance throughout the entire zoom range.

[0051] Conversely, if the value in condition (2) falls below the lower limit, the refractive power configuration becomes less telephotonic, making it difficult to shorten the optical length of the zoom lens at the telephoto end relative to the focal length. On the other hand, if the value in condition (2) exceeds the upper limit, the telephotonic tendency becomes too strong, increasing the amount of aberrations. This requires more lenses to correct, making it difficult to realize a zoom lens with high imaging performance using a small number of lenses.

[0052] To obtain the above effect, the upper limit of conditional expression (2) is more preferably 2.3, even more preferably 2.1, and even more preferably 2.0. Furthermore, the lower limit of conditional expression (2) is more preferably 1.2, and even more preferably 1.25.

[0053] 1-3-3. Conditional expression (3) The zoom lens preferably satisfies the following condition. (3) 0.3 ≤ BFw / Y ≤ 1.5 however, BFw: Back focus of the zoom lens at the wide-angle end. Y: Maximum image height of the zoom lens

[0054] Conditional equation (3) defines the ratio of the back focus of the zoom lens at the wide-angle end to the maximum image height of the zoom lens. By satisfying conditional equation (3), it is possible to realize a compact zoom lens with a short back focus at the wide-angle end and a small exit pupil diameter.

[0055] Conversely, if the value in condition (3) falls below the lower limit, the back focus of the zoom lens at the wide-angle end becomes too short, and the angle of inclination of the incident light on the image sensor with respect to the optical axis becomes too large. To reduce the angle of inclination of the incident light on the image sensor with respect to the optical axis, it is necessary to increase the exit pupil diameter. Therefore, it becomes difficult to reduce the diameter of the lens group GB. On the other hand, if the value in condition (3) exceeds the upper limit, the back focus of the zoom lens at the wide-angle end becomes too long, making it difficult to shorten the overall optical length of the zoom lens at the wide-angle end.

[0056] To obtain the above effect, the upper limit of conditional expression (3) is more preferably 1.3, even more preferably 1.2, and even more preferably 1.1. Furthermore, the lower limit of conditional expression (3) is more preferably 0.4, and even more preferably 0.5.

[0057] 1-3-4. Conditional expression (4) The zoom lens preferably satisfies the following condition. (4) 0.5 ≤ fP / Y ≤ 2.7 however, fP: Focal length of the positive lens component P Y: Maximum image height of the zoom lens

[0058] Conditional equation (4) defines the ratio of the focal length of the positive lens component P to the maximum image height of the zoom lens. By satisfying conditional equation (4), the refractive power of the positive lens component P is within an appropriate range, enabling the realization of a zoom lens with high imaging performance using a small number of lenses, while also reducing the diameter of the lens group GB.

[0059] Conversely, if the value in conditional equation (4) falls below the lower limit, the refractive power of the positive lens component P becomes too strong, making it difficult to adequately correct aberrations with a small number of lenses. In particular, in this case, it becomes difficult to adequately correct field curvature and distortion at the wide-angle end, and difficult to adequately correct spherical aberration at the telephoto end. On the other hand, if the value in conditional equation (4) exceeds the upper limit, the refractive power of the positive lens component P weakens, and the height of the obliquely incident light beam passing through lens group GB from the optical axis increases, making it difficult to reduce the diameter of lens group GB.

[0060] To obtain the above effect, the upper limit of conditional expression (4) is more preferably 2.6, even more preferably 2.3, even more preferably 2.1, and even more preferably 1.9. Also, the lower limit of conditional expression (4) is more preferably 0.6, even more preferably 0.7, and even more preferably 0.8.

[0061] 1-3-5. Conditional expression (5) The zoom lens preferably satisfies the following condition. (5) 0.4 ≤ |fN| / Y ≤ 2.7 however, fN: Combined focal length of negative lens component Nf and negative lens component Nb Y: Maximum image height of the zoom lens

[0062] Conditional equation (5) defines the ratio of the combined focal length of adjacent negative lens components Nf and Nb to the maximum image height of the zoom lens. By satisfying conditional equation (5), the exit pupil position can be positioned appropriately in the zoom lens, and at the same time, good image plane can be obtained.

[0063] Conversely, if the value of condition equation (5) falls below the lower limit, the divergence effect due to the negative lens components Nf and Nb becomes too strong, causing the field curvature to over-curve, making it difficult to correct this effectively. On the other hand, if the value of condition equation (5) exceeds the upper limit, it becomes impossible to position the exit pupil closer to the image side, making it difficult to reduce the diameter of the lens group GB.

[0064] To obtain the above effect, the upper limit of conditional expression (5) is more preferably 2.4, even more preferably 2.2, and even more preferably 2.0. Furthermore, the lower limit of conditional expression (5) is more preferably 0.5, even more preferably 0.6, and even more preferably 0.7.

[0065] 1-3-6. Conditional expression (6) The zoom lens preferably satisfies the following condition. (6) 0.2 ≤ RP / fw ≤ 2.5 however, RP: Radius of curvature of the object's side surface with respect to the positive lens component P. fw: Focal length of the zoom lens at the wide-angle end

[0066] Conditional equation (6) defines the ratio of the radius of curvature of the object's side surface for the positive lens component P to the focal length of the zoom lens at the wide-angle end. By satisfying conditional equation (6), spherical aberration and field curvature can be corrected in a well-balanced manner.

[0067] Conversely, if the value of condition equation (6) falls below the lower limit, the refractive effect of the obliquely incident light beam becomes stronger than that of the on-axial light beam, resulting in a large field curvature and a tendency towards underexposure, making it impossible to balance with spherical aberration. On the other hand, if the value of condition equation (6) exceeds the upper limit, the field curvature becomes large and a tendency towards underexposure, making it difficult to balance with spherical aberration.

[0068] To obtain the above effect, the upper limit of conditional expression (6) is more preferably 2.3, even more preferably 2.1, and even more preferably 1.9. Furthermore, the lower limit of conditional expression (6) is more preferably 0.3, even more preferably 0.4, and even more preferably 0.45.

[0069] 1-3-7. Conditional expression (7) The zoom lens preferably satisfies the following condition. (7) 0.2 ≤ fNf / fNb ≤ 1.8 however, fNf: Focal length of the negative lens component Nf fNb: Focal length of the negative lens component Nb

[0070] Conditional equation (7) defines the ratio of the focal length of the negative lens component Nf to the focal length of the negative lens component Nb. By satisfying conditional equation (7), lens group G B This makes it easier to reduce the eccentricity sensitivity of each lens component, thereby suppressing the degradation of optical performance due to eccentricity errors during manufacturing. In other words, it reduces manufacturing variations and improves yield.

[0071] Conversely, if the value in conditional equation (7) falls below the lower limit, the refractive power of the negative lens component Nf becomes too strong, increasing the eccentricity sensitivity between the negative lens component Nf and the positive lens component P, making it difficult to suppress the deterioration of optical performance due to eccentricity errors during manufacturing. On the other hand, if the value in conditional equation (7) exceeds the upper limit, the refractive power of the negative lens component Nb becomes too strong, increasing the eccentricity sensitivity between the negative lens component Nb and the positive lens component P, and in this case as well, it becomes difficult to suppress the deterioration of optical performance due to eccentricity errors during manufacturing.

[0072] To obtain the above effect, the upper limit of conditional expression (7) is more preferably 1.7, even more preferably 1.6, and even more preferably 1.5. Furthermore, the lower limit of conditional expression (7) is more preferably 0.3, and even more preferably 0.4.

[0073] 1-3-8. Conditional expression (8) The zoom lens preferably satisfies the following condition. (8) 20 ≤ νP ≤ 45 however, νP: The Abbe number for the d line of the positive lens with the smallest Abbe number, contained in the positive lens component P.

[0074] Conditional equation (8) defines the Abbe number for the d-line of the positive lens with the smallest Abbe number included in the positive lens component P. Here, if the positive lens component P is composed of positive lenses, νP refers to the Abbe number for the d-line of that positive lens. If the positive lens component P is composed of a cemented lens including positive lenses, νP refers to the Abbe number for the d-line of the positive lens with the smallest Abbe number for the d-line among the positive lenses included in the cemented lens. By satisfying conditional equation (8), axial chromatic aberration and lateral chromatic aberration can be corrected in a balanced manner across the entire zoom range.

[0075] Conversely, if the value of condition equation (8) falls below the lower limit, the difference between the lateral chromatic aberration of the F line and the lateral chromatic aberration of the C line becomes large at the wide-angle end, making correction difficult. On the other hand, if the value of condition equation (8) exceeds the upper limit, the difference between the axial chromatic aberration of the F line and the axial chromatic aberration of the C line becomes large, especially at the telephoto end, making correction difficult.

[0076] To obtain the above effect, the upper limit of conditional expression (8) is more preferably 43, even more preferably 40, and even more preferably 38. Furthermore, the lower limit of conditional expression (8) is more preferably 23, and even more preferably 25.

[0077] 2. Imaging device Next, the 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 image sensor on the image plane side of the zoom lens that converts the optical image formed by the zoom lens into an electrical signal.

[0078] There are no particular limitations on the image sensor, and solid-state image sensors such as CCD (Charge Coupled Device) sensors and CMOS (Complementary Metal Oxide Semiconductor) sensors can also be used. The imaging device according to the present invention is suitable for imaging devices using such solid-state image sensors, such as digital cameras and video cameras. Furthermore, the imaging device may be a fixed-lens type imaging device in which the lens is fixed to the housing, or a lens-interchangeable type imaging device such as a mirrorless single-lens reflex camera.

[0079] It is preferable that the imaging device includes an image processing unit that electrically processes the image data acquired by the image sensor to change the shape of the image, and an image correction data holding unit that holds image correction data, image correction programs, etc., used to process the image data in the image processing unit. When a zoom lens is miniaturized, distortion (bending) of the shape of the image formed at the image plane is more likely to occur. In this case, it is preferable to store distortion correction data in advance in the image correction data holding unit to correct the distortion of the shape of the image, and then correct the distortion of the shape of the image using the distortion correction data held in the image correction data holding unit in the image processing unit. With such an imaging device, the zoom lens can be miniaturized even further, a beautiful image can be obtained, and the entire imaging device can be miniaturized.

[0080] Furthermore, in the imaging device according to the present invention, it is preferable to pre-store chromatic aberration correction data in the image correction data holding unit, and to have the image processing unit perform chromatic aberration correction of the captured image using the chromatic aberration correction data stored in the image correction data holding unit. By correcting chromatic aberration, that is, the difference in magnification due to color, by the image processing unit, it becomes possible to reduce the number of lenses constituting the optical system. 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.

[0081] Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples. The zoom lenses in each of the following examples are zoom lenses (variable magnification optical systems) used in the above-mentioned imaging device (optical device), and can be preferably applied to imaging devices to which a lens exchange system is applied. In each cross-sectional view of the lens, the left side in the view of the drawing is the object side, and the right side is the image side. [Examples]

[0082] (1) Optical configuration of the zoom lens Figure 1 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 1 of the present invention when it is focused at infinity at the wide-angle end. In the figure, "IP" refers to the image plane, specifically the imaging surface of a solid-state image sensor such as a CCD sensor or CMOS sensor, or the film surface of a silver halide film. The object side of the image plane IP is also provided with a parallel plate that has virtually no refractive power, such as a cover glass "CG". These points are the same in the cross-sectional views of the lenses shown in other embodiments, so a further explanation is omitted below.

[0083] The zoom lens of Example 1 is composed of a front group and lens group GB, in order from the object side, having a positive refractive power as a whole. The front group is composed of a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a positive refractive power, and a sixth lens group G6 having a negative refractive power, in order from the object side. The sixth lens group G6 corresponds to lens group GF. Lens group GB is composed of a seventh lens group G7 having a negative refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side of the third lens group G3.

[0084] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a cemented lens formed by joining a negative meniscus lens L1 and a biconvex lens L2, both with their convex surfaces facing the object, and a positive meniscus lens L3 with its convex surface facing the object.

[0085] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object side, and a cemented lens formed by joining three lenses: a biconcave lens L5, 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 glass-molded aspherical lens with an aspherical shape on the object side.

[0086] The third lens group G3 consists of, in order from the object side, a positive meniscus lens L8 with its convex surface facing the object, a biconvex lens L9, and a cemented lens formed by joining a negative meniscus lens L10 and a biconvex lens L11, both with their convex surfaces facing the object.

[0087] The fourth lens group G4 consists of a biconcave lens L12. The biconcave lens L12 is a composite resin type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object.

[0088] The fifth lens group G5 consists, in order from the object side, of a biconvex lens L13, and a cemented lens formed by joining a negative meniscus lens L14 and a biconvex lens L15, with the convex side facing the object. The biconvex lens L13 is a glass molded aspherical lens with aspherical shapes on both sides.

[0089] The sixth lens group G6 consists of a negative meniscus lens L16 with its convex surface facing the object. The negative meniscus lens L16 is a glass-molded aspherical lens with aspherical shapes on both sides.

[0090] The seventh lens group G7 consists of, in order from the object side, a biconvex lens L17, a biconcave lens L18, and a negative meniscus lens L19 with its convex surface facing the image side. Here, the biconvex lens L17 corresponds to the positive lens component P, the biconcave lens L18 corresponds to the negative lens component Nf, and the negative meniscus lens L19 corresponds to the negative lens component Nb.

[0091] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 first moves toward the image side and then toward the object, the third lens group G3 moves toward the object, the fourth lens group G4 moves toward the object, the fifth lens group G5 moves toward the object, the sixth lens group G6 moves toward the object, and the seventh lens group G7 moves toward the object. During zooming, the third lens group G3, the fifth lens group G5, and the seventh lens group G7 move along the same trajectory.

[0092] Focusing from an object at infinity to an object at close range is achieved by moving the sixth lens group G6 towards the image along the optical axis.

[0093] (2) Numerical Examples Next, we will describe numerical examples that apply the specific numerical values ​​of the zoom lens. Table 1 shows the surface data of the zoom lens of Example 1 according to the present invention (surfaces 36 and 37 in Table 1 are surface data of the cover glass CG). In Table 1, "surface number" is the order of the lens surfaces counted from the object side, "r" is the radius of curvature of the lens surface, "d" is the distance of the lens surfaces on the optical axis, "nd" is the refractive index for the d line (wavelength λ = 587.56 nm), and "νd" is the Abbe number for the d line. In addition, "*" displayed to the right of the surface number indicates that the lens surface is aspherical, and "S" indicates the aperture diaphragm. Furthermore, "d(5)", "d(11)", etc. in the column for the distance of the lens surfaces on the optical axis means that the distance of the lens surfaces on the optical axis is a variable distance that changes when the magnification is changed. Note that the unit of length in each table is "mm", and "∞" in the radius of curvature column means a plane.

[0094] Table 2 is the specifications table for the zoom lens. This table shows the focal length "f", f-number "Fno.", half-angle of view "ω", and maximum image height "Y" of the zoom lens when focused at infinity. However, Table 2 shows the values ​​at the wide-angle end, intermediate focal length position, and telephoto end, from left to right. All lengths in the table are in "mm", and all angles of view are in "°".

[0095] Table 3 shows the variable spacing on the optical axis of the zoom lens when focused at infinity (∞) and when focused on a close object (shooting distances from left to right: wide-angle end: 300mm, intermediate focal length position: 500mm, telephoto end: 800mm). In Table 3, the variable spacing when focused at infinity (∞) and when focused on a close object is shown from left to right at the wide-angle end, intermediate focal length position, and telephoto end, respectively.

[0096] Table 4 shows the focal lengths of each lens group that makes up the zoom lens.

[0097] Table 5 shows the aspherical coefficients of each aspherical surface. The aspherical coefficients are the values when each aspherical shape is defined by the following formula.

[0098] X = (H 2 / r) / [1 + {1 - (1 + k)·(H / r) 2}^ 1 / 2 + A4·H 4 + A6·H 6 + A8·H 8 + A10·H 10 + A12·H 12

[0099] However, in the above formula, "X" is the displacement amount from the reference plane in the optical axis direction, "r" is the paraxial curvature radius, "H" is the height from the optical axis in the direction perpendicular to the optical axis, "k" is the conic constant (conic coefficient), and "An" is the aspherical coefficient of the nth order. Also, in Table 5, "E-n" indicates "×10 -n ".

[0100] Table 46 also shows the values of conditional expressions (1) to (8) and each value used in the calculation of conditional expressions (1) to (8).

[0101] Since the matters related to each of the above tables are the same in the tables shown in other embodiments, the description will be omitted below.

[0102] [Table 1] Surface number r d nd νd Object surface ∞ d(0) 1 126.8033 1.2000 1.85478 24.80 2 73.1163 6.5498 1.49700 81.61 3 -619.9628 0.2000 4 57.8673 4.7502 1.59349 67.00 5 168.1327 d(5) 6* 73.0270 1.1000 1.87070 40.73 7 20.1788 6.5245 8 -59.9309 0.8000 1.87070 40.73 9 32.6271 6.1879 1.84666 23.78 10 -33.8219 0.9000 1.80420 46.50 11 -633.2189 d(11) 12S ∞ 1.2000 13 34.8967 2.5748 1.85478 24.80 14 105.2664 0.2143 15 48.7916 2.8950 1.72916 54.67 16 -207.3456 0.2000 17 101.3163 0.9000 1.80809 22.76 18 29.9068 3.5853 1.49700 81.61 19 -132.7415 d(19) 20* -23.7077 0.2468 1.51460 49.96 21 -25.7724 0.8000 1.85150 40.78 22 65.2251 d(22) 23* 23.0080 6.3068 1.69350 53.18 24* -48.1474 0.2000 25 37.0746 0.8000 1.91082 35.25 26 16.3655 6.4374 1.49700 81.61 27 -35.1960 d(27) 28* 79.0659 0.9000 1.59201 67.02 29* 19.9423 d(29) 30 36.6023 6.3766 1.67270 32.10 31 -45.2833 0.2000 32 -303.8734 0.9000 1.85150 40.78 33 40.0745 6.5841 34 -21.0548 1.0000 1.72916 54.68 35 -52.1735 d(35) 36 ∞ 2.5000 1.51680 64.20 37 ∞ 1.0000 Image plane ∞

[0103] [Table 2] Wide-angle end, Mid-range, Telephoto end f 28.7936 75.0289 193.9307 FNo. 2.8965 4.1889 5.7781 ω 37.6195 15.3512 6.1472 Y 21.6330 21.6330 21.6330

[0104] [Table 3] Wide-angle end, intermediate, telephoto end, wide-angle end, intermediate, telephoto end d(0) ∞ ∞ ∞ 165.7499 340.7231 610.7498 d(5) 0.8000 24.6717 48.0431 0.8000 24.6717 48.0431 d(11) 24.4154 10.1212 2.1272 24.4154 10.1212 2.1272 d(19) 2.2954 4.0353 6.4036 2.2954 4.0353 6.4036 d(22) 5.2082 3.4678 1.1000 5.2082 3.4678 1.1000 d(27) 1.3034 2.3598 1.4441 2.8006 5.0953 8.0146 d(29) 12.6942 11.6380 12.5536 11.1970 8.9024 5.9831 d(35) 13.4999 28.9498 43.5451 13.4999 28.9498 43.5451

[0105] [Table 4] G1 106.0065 G2 -21.9002 G3 28.3494 G4 -20.7806 G5 19.0830 G6 -45.3040 G7 -144.1356

[0106] [Table 5] Surface number k A4 A6 A8 A10 A12 6 0.0000 -9.86089E-07 -9.19169E-10 -2.48794E-12 1.49982E-15 0.00000E+00 20 -0.1591 3.73272E-05 -9.02045E-08 9.87967E-10 -7.53595E-12 2.38762E-14 23 0.3924 -2.16911E-05 8.68108E-09 1.11227E-09 -1.16883E-11 4.79637E-14 24 0.0000 3.27128E-05 -1.04498E-07 2.33175E-09 -2.01761E-11 7.62655E-14 28 0.0000 -2.55954E-05 3.56502E-07 -1.70180E-09 -6.24255E-12 6.45296E-14 29 0.0000 -3.14993E-05 4.15457E-07 -2.60403E-09 -9.27673E-13 5.04098E-14

[0107] Furthermore, Figures 2 to 4 show the longitudinal aberration diagrams of the zoom lens of Embodiment 1 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively. The longitudinal aberration diagrams shown in each figure, from left to right, represent spherical aberration (mm), astigmatism (mm), and distortion (%), respectively. In the diagram showing spherical aberration, the vertical axis is the ratio to the maximum aperture, and the horizontal axis is defocus. The solid line shows spherical aberration at the d line (wavelength λ=587.56nm), the dashed line shows spherical aberration at the C line (wavelength λ=656.28nm), and the dashed line shows spherical aberration at the g line (wavelength λ=435.84nm). In the diagram showing astigmatism, the vertical axis is the half-angle of view, and the horizontal axis is defocus. The solid line shows the sagittal image plane (ds) relative to the d line, and the dashed line shows the meridional image plane (dm) relative to the d line. In the diagrams showing distortion, the vertical axis represents the half-angle of view, and the horizontal axis represents the percentage of distortion. Since the same applies to the longitudinal aberration diagrams shown in other embodiments, further explanation is omitted below. [Examples]

[0108] (1) Optical configuration of the zoom lens Figure 5 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 2 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens is composed of, in order from the object side, a front group having a positive refractive power as a whole, and lens group GB.

[0109] The front group consists of, in order from the object side, 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 negative refractive power, a fifth lens group G5 with positive refractive power, and a sixth lens group G6 with negative refractive power. The sixth lens group G6 corresponds to lens group GF. Lens group GB consists of a seventh lens group G7 with negative refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side of the third lens group G3.

[0110] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a cemented lens formed by joining a negative meniscus lens L1 and a biconvex lens L2, both with their convex surfaces facing the object, and a positive meniscus lens L3 with its convex surface facing the object.

[0111] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object side, a cemented lens formed by joining 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 type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object.

[0112] The third lens group G3 consists of, in order from the object side, a biconvex lens L8 and a cemented lens formed by a biconvex lens L9 and a negative meniscus lens L10 with its convex surface facing the image side.

[0113] The fourth lens group G4 consists of a biconcave lens L11. The biconcave lens L11 is a composite resin type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object.

[0114] The fifth lens group G5 consists, in order from the object side, of a biconvex lens L12, and a cemented lens formed by joining a negative meniscus lens L13 and a biconvex lens L14, with the convex side facing the object. The biconvex lens L12 is a glass molded aspherical lens with aspherical shapes on both sides.

[0115] The sixth lens group G6 consists of a negative meniscus lens L15 with its convex surface facing the object. The negative meniscus lens L15 is a glass-molded aspherical lens with aspherical shapes on both sides.

[0116] The seventh lens group G7 consists of, in order from the object side, a biconvex lens L16, a biconcave lens L17, and a negative meniscus lens L18 with its convex surface facing the image side. Here, the biconvex lens L16 corresponds to the positive lens component P, the biconcave lens L17 corresponds to the negative lens component Nf, and the negative meniscus lens L18 corresponds to the negative lens component Nb.

[0117] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 first moves toward the image side and then toward the object, the third lens group G3 moves toward the object, the fourth lens group G4 moves toward the object, the fifth lens group G5 moves toward the object, the sixth lens group G6 moves toward the object, and the seventh lens group G7 moves toward the object. During zooming, the third lens group G3, the fifth lens group G5, and the seventh lens group G7 move along the same trajectory.

[0118] Focusing from an object at infinity to an object at close range is achieved by moving the fourth lens group G4 along the optical axis towards the object.

[0119] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 6 shows the surface data of the zoom lens. Table 7 shows the specifications of the zoom lens. Table 8 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distances from left to right are: wide-angle end: 500mm, intermediate focal length position: 500mm, telephoto end: 800mm). Table 9 shows the focal lengths of each lens group that constitutes the zoom lens. Table 10 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 10 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0120] Furthermore, Figures 5 to 8 show the longitudinal aberration diagrams of the zoom lens of Embodiment 2 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0121] [Table 6] Face number rd nd νd Object plane ∞ d(0) 1 149.3109 1.2000 1.85478 24.80 2 76.0948 7.1171 1.49700 81.61 3 -1072.3665 0.2000 4 66.0148 5.5600 1.59349 67.00 5 283.4193 d(5) 6* 131.1407 0.1500 1.51460 49.96 7 117.0450 1.1000 1.90366 31.31 8 22.8085 5.5879 9 -107.5361 0.8000 1.83481 42.72 10 24.0970 5.5879 1.84666 23.78 11 -64.4752 0.6867 12 -39.5818 0.9000 1.80420 46.50 13 -185.3667 d(13) 14S ∞ 1.2000 15 33.8846 3.2667 1.80000 29.84 16 -332.6257 0.2000 17 5000.0000 3.7611 1.57501 41.50 18 -24.4679 0.9000 1.83400 37.21 19 -43.8545 d(19) 20* -22.9591 0.1500 1.51460 49.96 21 -26.0428 0.8000 1.87070 40.73 22 53.6491 d(22) 23* 28.6779 4.6565 1.69350 53.18 24* -36.5598 0.2000 25 34.5392 0.8000 1.92119 23.96 26 19.3565 7.5164 1.49700 81.61 27 -48.5874 d(27) 28* 57.6247 0.9000 1.68893 31.16 29* 25.8168 d(29) 30 40.1744 9.5000 1.64769 33.79 31 -25.7354 0.2000 32 -28.7174 0.9000 1.87070 40.73 33 120.1990 5.7951 34 -16.0000 1.0000 1.72916 54.67 35 -26.9906 d(35) 36 ∞ 2.5000 1.51680 64.20 37 ∞ 1.0000 Image plane ∞

[0122] [Table 7] Wide-angle end, Mid-range, Telephoto end f 28.8088 74.9934 193.9843 FNo. 3.5613 4.4997 5.7497 ω 38.9265 15.4642 6.1181 Y 21.6330 21.6330 21.6330

[0123] [Table 8] Wide-angle end, intermediate, telephoto end, wide-angle end, intermediate, telephoto end d(0) ∞ ∞ ∞ 365.0001 336.8530 605.0002 d(5) 1.1522 30.8984 55.1293 1.1522 30.8984 55.1293 d(13) 22.1323 7.0681 1.6849 22.1323 7.0681 1.6849 d(19) 2.4416 3.6056 7.1001 1.4943 1.8713 4.1187 d(22) 5.3399 4.1757 0.6812 6.2872 5.9101 3.6627 d(27) 1.2932 4.9795 8.9510 1.2932 4.9795 8.9510 d(29) 12.8482 9.1620 5.1904 12.8482 9.1620 5.1904 d(35) 15.6570 29.1223 42.1273 15.6570 29.1223 42.1273

[0124] [Table 9] G1 118.8991 G2 -22.4091 G3 29.9675 G4 -18.9990 G5 18.6329 G6 -68.6819 G7 -97.2914

[0125] [Table 10] Surface number k A4 A6 A8 A10 A12 6 0.0000 8.87003E-07 2.06774E-09 -1.18068E-11 2.04323E-14 0.00000E+00 20 1.7375 4.27377E-05 5.59066E-08 5.40110E-10 -1.90435E-12 1.76795E-14 23 0.3977 -1.92166E-05 -8.94668E-09 5.51734E-10 -5.49188E-12 1.83133E-14 24 0.0000 9.06050E-06 -2.84346E-08 5.73029E-10 -4.90970E-12 1.56700E-14 28 0.0000 -2.00094E-05 1.97916E-07 -1.34790E-09 2.09962E-12 2.13721E-14 29 0.0000 -1.78331E-05 2.09037E-07 -1.29736E-09 5.07192E-13 3.57901E-14 [Examples]

[0126] (1) Optical configuration of the zoom lens Figure 9 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 3 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0127] The front group consists of, in order from the object side, 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 negative refractive power, a fifth lens group G5 with positive refractive power, and a sixth lens group G6 with negative refractive power. The sixth lens group G6 corresponds to lens group GF. Lens group GB consists of a seventh lens group G7 with negative refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side of the third lens group G3.

[0128] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a cemented lens formed by joining a negative meniscus lens L1 and a biconvex lens L2, both with their convex surfaces facing the object, and a positive meniscus lens L3 with its convex surface facing the object.

[0129] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object, a biconcave lens L5, 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 glass-molded aspherical lens with an aspherical shape on the object side.

[0130] The third lens group G3 consists of, in order from the object side, a positive meniscus lens L8 with its convex surface facing the object, a positive meniscus lens L9 with its convex surface facing the object, and a cemented lens formed by joining a negative meniscus lens L10 and a biconvex lens L11, both with their convex surfaces facing the object. The positive meniscus lens L8 is a glass-molded aspherical lens with aspherical shapes on both sides.

[0131] The fourth lens group G4 consists of a cemented lens formed by joining a biconcave lens L12 and a positive meniscus lens L13 with its convex surface facing the object, in that order from the object side.

[0132] The fifth lens group G5 consists of a cemented lens formed by joining a negative meniscus lens L14 with its convex surface facing the object and a positive meniscus lens L15 with its convex surface facing the object, and a biconvex lens L16, in that order from the object side. The biconvex lens L16 is a glass molded aspherical lens with aspherical shapes on both sides.

[0133] The sixth lens group G6 consists of a negative meniscus lens L17 with its convex surface facing the object. The negative meniscus lens L17 is a glass-molded aspherical lens with an aspherical shape on the image side.

[0134] The seventh lens group G7 consists of, in order from the object side, a biconvex lens L18, a biconcave lens L19, and a negative meniscus lens L20 with its convex surface facing the image side. Here, the biconvex lens L18 corresponds to the positive lens component P, the biconcave lens L19 corresponds to the negative lens component Nf, and the negative meniscus lens L20 corresponds to the negative lens component Nb.

[0135] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 first moves toward the image side and then toward the object, the third lens group G3 moves toward the object, the fourth lens group G4 moves toward the object, the fifth lens group G5 moves toward the object, the sixth lens group G6 moves toward the object, and the seventh lens group G7 moves toward the object. During zooming, the third lens group G3, the fifth lens group G5, and the seventh lens group G7 move along the same trajectory.

[0136] Focusing from an object at infinity to an object at close range is achieved by moving the sixth lens group G6 towards the image along the optical axis.

[0137] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 11 shows the surface data of the zoom lens. Table 12 shows the specifications of the zoom lens. Table 13 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distances from left to right: wide-angle end: 300 mm, intermediate focal length position: 500 mm, telephoto end: 800 mm). Table 14 shows the focal lengths of each lens group that constitutes the zoom lens. Table 15 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 15 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0138] Furthermore, Figures 10 to 12 show the longitudinal aberration diagrams of the zoom lens of Embodiment 3 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0139] [Table 11] Face number rd nd νd Object plane ∞ d(0) 1 72.7418 1.2000 1.85478 24.80 2 55.0925 7.1178 1.49700 81.61 3 -2576.0254 0.2000 4 67.9905 3.3979 1.59349 67.00 5 131.2902 d(5) 6* 81.8222 1.1000 1.87070 40.73 7 17.3549 7.3619 8 -46.9936 0.8000 1.87070 40.73 9 55.3112 0.1500 10 37.6438 6.1652 1.85478 24.80 11 -32.9640 0.9561 12 -26.2287 0.9000 1.83481 42.72 13 -101.7927 d(13) 14S ∞ 1.2000 15* 37.1604 2.7113 1.69350 53.18 16 * 132.8507 0.2000 17 38.9190 3.0811 1.60311 60.69 18 682.8260 0.2000 19 42.5438 0.8000 1.80000 29.84 20 17.2829 5.3715 1.59282 68.62 21 -174.6671 d(21) 22 -85.1322 0.8000 1.78800 47.37 23 21.4134 2.9687 1.85478 24.80 24 58.4808 d(24) 25 51.7474 0.8000 1.90366 31.31 26 17.9175 2.8921 1.49700 81.61 27 43.1221 0.2000 28* 20.7365 5.6905 1.59201 67.02 29* -28.6011 d(29) 30 190.9486 0.9000 1.59201 67.02 31* 20.2337 d(31) 32 36.8017 7.0403 1.60342 38.03 33 -31.9447 0.2000 34 -58.6191 0.9000 1.88300 40.80 35 340.8507 4.3067 36 -24.4531 1.0000 1.80420 46.50 37 -104.9522 d(37) 38 ∞ 2.5000 1.51680 64.20 39 ∞ 1.0000 Image plane ∞

[0140] [Table 12] Wide-angle end, middle viewing end f 28.8003 75.0027 193.9288 FNo. 2.8982 4.5018 5.7528 ω 37.0367 15.3644 6.1210 Y 21.6330 21.6330 21.6330

[0141] [Table 13] Wide-angle end, center telephoto end. d(0) ∞ ∞ ∞ 165.0002 341.3593 610.0000 d(5) 0.8000 21.8724 50.6988 0.8000 21.8724 50.6988 d(13) 24.8447 9.6041 1.7762 24.8447 9.6041 1.7762 d(21) 1.4907 4.5549 7.0064 1.4907 4.5549 7.0064 d(24) 6.6157 3.5515 1.1000 6.6157 3.5515 1.1000 d(29) 4.6632 4.9482 1.3034 6.2596 7.5604 7.6792 d(31) 8.9747 8.6898 12.3345 7.3783 6.0775 5.9587 d(37) 13.4998 31.3089 41.6697 13.4998 31.3089 41.6697

[0142] [Table 14] G1 103.1709 G2 -19.9223 G3 27.1565 G4 -47.7441 G5 31.2329 G6 -38.3038 G7 -298.9440

[0143] [Table 15] Surface number k A4 A6 A8 A10 A12 6 0.0000 1.11737E-06 7.19073E-10 -1.04952E-11 3.44628E-14 0.00000E+00 15 0.8177 -6.08206E-06 2.68573E-08 3.62072E-11 -1.38597E-13 5.64966E-15 16 0.0000 -1.55722E-06 3.17267E-08 1.05195E-10 -6.46114E-13 7.81993E-15 28 -0.4515 -1.96769E-05 3.02593E-09 1.65183E-10 -2.06130E-12 4.64386E-15 29 -1.4863 2.82074E-06 -4.69572E-08 1.82020E-10 -1.21460E-12 -4.72267E-16 31 0.0000 -9.57691E-06 7.26474E-09 2.57523E-10 -2.29565E-12 1.06894E-14 [Examples]

[0144] (1) Optical configuration of the zoom lens Figure 13 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 4 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0145] The front group consists of, in order from the object side, 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 negative refractive power, a fifth lens group G5 with positive refractive power, and a sixth lens group G6 with negative refractive power. The sixth lens group G6 corresponds to lens group GF. Lens group GB consists of a seventh lens group G7 with negative refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side of the third lens group G3.

[0146] The configuration of each lens group is described below. The first lens group G1 consists of a bonded lens formed by joining a negative meniscus lens L1 and a biconvex lens L2, with the convex surface facing the object, and a biconvex lens L3, in that order from the object side.

[0147] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object side, a biconcave lens L5, a biconvex lens L6, and a cemented lens formed by joining a negative meniscus lens L7 with its convex surface facing the image side. The negative meniscus lens L4 is a glass molded aspherical lens with aspherical shapes on both sides.

[0148] The third lens group G3 consists of, in order from the object side, a biconvex lens L8, a positive meniscus lens L9 with its convex surface facing the object side, and a cemented lens formed by joining a biconvex lens L10 and a biconcave lens L11.

[0149] The fourth lens group G4 consists of a cemented lens formed by joining a biconcave lens L12 and a positive meniscus lens L13 with its convex surface facing the object, in that order from the object side. The biconcave lens L12 is a glass-molded aspherical lens with an aspherical shape on the object side.

[0150] The fifth lens group G5 consists, in order from the object side, of a biconvex lens L14, and a cemented lens formed by joining a negative meniscus lens L15 and a biconvex lens L16, with the convex side facing the object. The biconvex lens L14 is a glass molded aspherical lens with aspherical shapes on both sides.

[0151] The sixth lens group G6 consists of a cemented lens formed by joining a biconvex lens L17 and a biconcave lens L18, in order from the object side. The biconcave lens L18 is a glass-molded aspherical lens with an aspherical shape on the image side.

[0152] The seventh lens group G7 consists of, in order from the object side, a cemented lens formed by joining a biconcave lens L19 and a biconvex lens L20, a biconvex lens L21, a negative meniscus lens L22 with its convex surface facing the image side, and a negative meniscus lens L23 with its convex surface facing the image side. The biconcave lens L19 is a composite resin type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object. Here, the biconvex lens L21 corresponds to the positive lens component P, the negative meniscus lens L22 corresponds to the negative lens component Nf, and the negative meniscus lens L23 corresponds to the negative lens component Nb.

[0153] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 first moves toward the image side and then moves toward the object, the third lens group G3 moves toward the object, the fourth lens group G4 moves toward the object, the fifth lens group G5 moves toward the object, the sixth lens group G6 moves toward the object, and the seventh lens group G7 moves toward the object.

[0154] Focusing from an object at infinity to an object at close range is achieved by moving the sixth lens group G6 towards the image along the optical axis.

[0155] Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 16 shows the surface data of the zoom lens. Table 17 shows the specifications of the zoom lens. Table 18 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distances from left to right are: wide-angle end: 500 mm, intermediate focal length position: 700 mm, telephoto end: 1200 mm). Table 19 shows the focal lengths of each lens group that constitutes the zoom lens. Table 20 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 20 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0156] Furthermore, Figures 14 to 16 show the longitudinal aberration diagrams of the zoom lens of Embodiment 4 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0157] [Table 16] Face number rd nd νd Object plane ∞ d(0) 1 192.6617 1.3000 1.87070 40.73 2 95.9244 7.4083 1.43700 95.10 3 -554.2655 0.2000 4 94.2764 6.5301 1.49700 81.61 5 -7370.9991 d(5) 6* 679.0773 1.3000 1.88202 37.22 7* 27.5984 6.8641 8 -73.8932 1.0000 1.88300 40.80 9 79.6776 0.1500 10 57.8945 7.0811 1.85478 24.80 11 -34.0424 1.0000 1.78590 44.20 12 -1463.4181 d(12) 13S ∞ 1.0000 14 45.4512 3.4975 1.64850 53.02 15 -4514.9247 0.2825 16 44.0199 3.4681 1.60342 38.03 17 1022.8033 0.2000 18 68.1589 3.3302 1.49700 81.61 19 -132.0158 1.0000 1.92286 20.88 20 99.2304 d(20) 21* -71.0569 1.2000 1.77377 47.17 22 36.5603 2.6661 1.92119 23.96 23 92.3328 d(23) 24* 25.1199 4.9010 1.69350 53.18 25* -98.8550 0.1500 26 98.6246 1.0000 1.91082 35.25 27 17.1392 6.6649 1.59282 68.62 28 -64.0599 d(28) 29 204.9516 2.8807 1.62004 36.26 30 -53.7779 1.0000 1.59201 67.02 31* 29.8860 d(31) 32* -162.6004 0.2500 1.51460 49.96 33 -101.8172 1.0000 2.00100 29.13 34 20.1279 5.5899 1.59551 39.24 ​​​​​​​​​​​​​​​​​​​​​​​​​​​​FNo. 3.6008 6.2008 6.4916 ω 38.5769 9.0404 3.0410 Y 21.6330 21.6330 21.6330

[0159] [Table 18] Wide-angle end, center telephoto end. d(0) ∞ ∞ ∞ 325.0000 480.3873 930.6798 d(5) 1.7332 50.3141 101.6060 1.7332 50.3141 101.6060 d(12) 46.5713 11.2573 1.8737 46.5713 11.2573 1.8737 d(20) 2.3437 3.9857 7.4130 2.3437 3.9857 7.4130 d(23) 10.3197 4.8164 1.2000 10.3197 4.8164 1.2000 d(28) 4.7875 8.3835 1.6036 5.8711 12.8913 14.9238 d(31) 5.0042 8.1145 16.2964 3.9206 3.6067 2.9762 d(41) 13.5000 42.0009 49.2670 13.5000 42.0009 49.2670

[0160] [Table 19] G1 163.4646 G2 -27.1555 G3 42.5800 G4 -58.9198 G5 30.1155 G6 -62.0549 G7 -52.1550

[0161] [Table 20] Face number k A4 A6 A8 A10 A12 6 0.0000 -6.33623E-07 5.25166E-09 -1.15628E-11 7.27254E-15 0.00000E+00 7 0.0000 2.74174E-07 1.99347E-09 2.62210E-11 -6.48205E-14 0.00000E+00 21 0.0000 2.01736E-06 1.91949E-09 -4.73234E-11 2.29474E-13 -2.05133E-16 24 0.0000 -7.39076E-06 -2.71133E-10 9.34250E-11 -4.95710E-13 2.17971E-15 25 0.0000 1.02751E-05 -7.03604E-09 4.20959E-11 -1.66847E-14 8.26127E-16 31 0.0000 -5.59575E-06 3.76510E-08 -5.94358E-10 3.17506E-12 0.00000E+00 32 0.0000 -8.92299E-06 4.32413E-08 -6.83984E-10 4.61131E-12 -1.71298E-15 [Examples]

[0162] (1) Optical configuration of the zoom lens Figure 17 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 5 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0163] The front group consists of, in order from the object side, 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, and a fourth lens group G4 with negative refractive power. The fourth lens group G4 corresponds to lens group GF. Lens group GB consists of a fifth lens group G5 with positive refractive power. The aperture diaphragm S is positioned adjacent to the object side of the third lens group G3.

[0164] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a cemented lens formed by joining a negative meniscus lens L1 and a biconvex lens L2, both with their convex surfaces facing the object, and a positive meniscus lens L3 with its convex surface facing the object.

[0165] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object, a biconcave lens L5, 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 glass-molded aspherical lens with an aspherical shape on the object side.

[0166] The third lens group G3 consists of, in order from the object side, a biconvex lens L8, a negative meniscus lens L9 with its convex surface facing the object, a bonded lens formed by joining a negative meniscus lens L10 with its convex surface facing the object and a positive meniscus lens L11 with its convex surface facing the object, and a biconvex lens L12. The biconvex lens L8 is a glass molded aspherical lens with aspherical shapes on both sides.

[0167] The fourth lens group G4 consists of a negative meniscus lens L13 with its convex surface facing the object. The negative meniscus lens L13 is a glass-molded aspherical lens with aspherical shapes on both sides.

[0168] The fifth lens group G5 consists of, in order from the object side, a biconvex lens L14, a biconcave lens L15, and a negative meniscus lens L16 with its convex surface facing the image side. Here, the biconvex lens L14 corresponds to the positive lens component P, the biconcave lens L15 corresponds to the negative lens component Nf, and the negative meniscus lens L16 corresponds to the negative lens component Nb.

[0169] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 moves toward the image, the third lens group G3 moves toward the object, the fourth lens group G4 moves toward the object, and the fifth lens group G5 moves toward the object. During zooming, the third lens group G3 and the fifth lens group G5 move along the same trajectory.

[0170] Focusing from an infinitely distant object to a close-distance object is performed by moving the fourth lens group G4 toward the image side along the optical axis.

[0171] (2) Numerical examples Next, numerical examples applying the specific numerical values of the zoom lens will be described. Table 21 shows the surface data of the zoom lens. Table 22 shows the starting points of the zoom lens. Table 23 shows the variable intervals on the optical axis of the zoom lens at infinity focus and at close-distance object focus (shooting distance = 500 mm). Table 24 shows the focal lengths of each lens group constituting the zoom lens. Table 25 shows the aspherical coefficients of each aspherical surface. Note that the aspherical coefficients not shown in Table 25 are 0.00. Also, Table 46 shows the values of conditional expressions (1) to (8) and each value used in the calculation of conditional expressions (1) to (8).

[0172] Furthermore, FIGS. 17 to 20 respectively show the longitudinal aberration diagrams at infinity focus at the wide-angle end, intermediate focal length position, and telephoto end of the zoom lens of Example 5.

[0173] [Table 21] Surface number r d nd νd Object surface ∞ d(0) 1 169.1758 1.3000 1.90525 35.04 2 81.6634 7.5716 1.49700 81.61 3 -1656.5789 0.2000 4 78.1124 6.4260 1.59282 68.62 5 725.1812 d(5) 6* 158.1127 1.4000 1.65100 56.24 7 24.2856 8.0217 8 -44.9153 0.9000 1.72916 54.67 9 123.6307 0.2000 10 57.0357 5.4113 1.80518 25.46 11 -83.8383 7.7671 12 -23.8514 1.0000 1.67003 47.23 13 -40.3623 d(13) 14S ∞ 1.2000 15* 23.4350 5.7748 1.59201 67.02 16* -101.1571 4.0777 17 30.3652 1.4907 1.80400 46.53 18 21.7617 1.2402 19 36.5459 0.9000 1.95375 32.32 20 16.5447 4.3221 1.49700 81.61 21 70.3425 0.2000 22 28.6539 4.7173 1.59282 68.62 23 -47.3256 d(23) 24* 279.9474 0.8000 1.59201 67.02 25* 19.5293 d(25) 26 40.9857 7.7026 1.60562 43.71 27 -41.7923 1.7653 28 -76.2569 0.9000 1.58913 61.13 29 80.9264 5.8177 30 -26.7232 1.0000 1.74320 49.34 31 -59.2219 d(31) 32 ∞ 2.5000 1.51680 64.20 33 ∞ 1.0000 Image plane ∞

[0174] [Table 22] Wide-angle end, Mid-range, Telephoto end f 36.0054 69.9898 145.5012 FNo. 2.9021 3.5240 4.1110 ω 31.7348 16.6038 8.1830 Y 21.6330 21.6330 21.6330

[0175] [Table 23] Wide-angle end, center telephoto end. d(0) ∞ ∞ ∞ 351.7464 334.4374 302.4795 d(5) 1.0000 25.6750 56.1506 1.0000 25.6750 56.1506 d(13) 27.5461 10.9512 1.3000 27.5461 10.9512 1.3000 d(23) 1.1228 2.6230 0.9999 2.0055 5.1121 8.2701 d(25) 17.7278 16.2280 17.8508 16.8452 13.7390 10.5806 d(31) 15.2508 24.4793 35.6132 15.2508 24.4793 35.6132

[0176] [Table 24] G1 134.6072 G2 -28.3313 G3 26.0220 G4 -35.5023 G5 303.7356

[0177] [Table 25] Face number k A4 A6 A8 A10 A12 6 0.0000 3.74943E-06 3.15104E-10 1.31029E-11 -3.81318E-14 7.24354E-17 15 0.2739 -7.80546E-06 -1.54896E-08 1.54159E-10 -1.13884E-12 2.75902E-15 16 -57.6238 7.25687E-06 -1.67175E-09 1.28764E-10 -1.00135E-12 2.74816E-15 24 0.0000 -3.92808E-06 -1.40084E-07 1.98829E-09 -1.24667E-11 3.06394E-14 25 0.0000 -1.20468E-05 -1.99489E-07 2.51719E-09 -1.74900E-11 4.70638E-14 [Examples]

[0178] (1) Optical configuration of the zoom lens Figure 21 is a cross-sectional view of a lens showing the lens configuration of the zoom lens of Embodiment 6 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0179] The front group consists of, in order from the object side, 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, and a fourth lens group G4 with negative refractive power. The fourth lens group G4 corresponds to lens group GF. Lens group GB consists of a fifth lens group G5 with positive refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side.

[0180] The configuration of each lens group is described below. The first lens group G1 consists of a cemented lens formed by joining a negative meniscus lens L1 with its convex surface facing the object and a positive meniscus lens L2 with its convex surface facing the object, and a positive meniscus lens L3 with its convex surface facing the object, in that order from the object side.

[0181] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L4 with its convex surface facing the object side, a cemented lens formed by joining 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 glass-molded aspherical lens with an aspherical shape on the object side, and the negative meniscus lens L7 is a glass-molded aspherical lens with an aspherical shape on both sides.

[0182] The third lens group G3 consists of, in order from the object side, a biconvex lens L8, a cemented lens formed by joining a biconvex lens L9 and a negative meniscus lens L10 with its convex surface facing the image side, a negative meniscus lens L11 with its convex surface facing the object side, and a biconvex lens L12. The biconvex lens L8 and the negative meniscus lens L11 are glass molded aspherical lenses, each with aspherical shapes on both sides.

[0183] The fourth lens group G4 consists of a negative meniscus lens L13 with its convex surface facing the object. The negative meniscus lens L13 is a glass-molded aspherical lens with aspherical shapes on both sides.

[0184] The fifth lens group G5 consists of, in order from the object side, a biconvex lens L14, a negative meniscus lens L15 with its convex surface facing the object side, and a negative meniscus lens L16 with its convex surface facing the image side. Here, the biconvex lens L14 corresponds to the positive lens component P, the negative meniscus lens L15 corresponds to the negative lens component Nf, and the negative meniscus lens L16 corresponds to the negative lens component Nb.

[0185] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the object, the second lens group G2 moves towards the image, the third lens group G3 moves towards the object, the fourth lens group G4 moves towards the object, and the fifth lens group G5 moves towards the object. During zooming, the third lens group G3 and the fifth lens group G5 move along the same trajectory.

[0186] Focusing from an object at infinity to an object at close range is achieved by moving the fourth lens group G4 towards the image along the optical axis.

[0187] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 26 shows the surface data of the zoom lens. Table 27 shows the specifications of the zoom lens. Table 28 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distance = 500 mm). Table 29 shows the focal lengths of each lens group that makes up the zoom lens. Table 30 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 30 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0188] Furthermore, Figures 22 to 24 show the longitudinal aberration diagrams of the zoom lens of Embodiment 6 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0189] [Table 26] Face number rd nd νd Object plane ∞ d(0) 1 313.5371 1.5000 1.84666 23.78 2 99.2888 6.4887 1.88300 40.80 3 697.1234 0.2000 4 67.8579 6.6276 1.61800 63.39 5 211.3308 d(5) 6* 185.5343 1.4000 1.80139 45.45 7 18.2676 9.6435 8 -99.2772 1.3000 1.69930 51.11 9 26.2105 10.0000 1.74950 35.28 10 -39.0628 1.3210 11* -27.8901 1.5000 1.59201 67.02 12* -50.9104 d(12) 13S ∞ 1.2000 14* 85.7451 2.3031 1.61881 63.85 15* -776.7378 9.8288 16 54.2110 7.6790 1.59282 68.62 17 -25.5578 1.2000 1.85026 32.27 18 -33.1229 0.2000 19* 547.9488 1.5000 1.73077 40.51 20 * 28.7932 0.2000 21 26.0335 7.8707 1.59282 68.62 22 -56.7976 d(22) 23* 129.0533 1.0000 1.86100 37.10 24* 24.5284 d(24) 25 43.1237 9.4497 1.56732 42.82 26 -35.6052 1.4436 27 783.3285 0.8000 1.59282 68.62 28 45.7837 7.3325 29 -22.7090 0.8000 1.89190 37.13 30 -36.7314 d(30) 31 ∞ 2.5000 1.51680 64.20 32 ∞ 1.0000 Image plane ∞

[0190] [Table 27] The corner end, the middle and the far end f 24.7000 49.9999 68.0000 FNo. 2.9028 2.9012 2.8996 ω 42.2046 22.5497 16.8380 Y 21.3000 21.3000 21.3000

[0191] [Table 28] Wide-angle end, center telephoto end. d(0) ∞ ∞ ∞ 351.1478 343.8881 329.5515 d(5) 1.0000 17.5230 33.0236 1.0000 17.5230 33.0236 d(12) 30.4410 6.1788 1.3000 30.4410 6.1788 1.3000 d(22) 3.6953 1.8047 1.0000 4.3398 3.3246 3.3989 d(24) 6.9276 8.8182 9.6230 6.2832 7.2983 7.2241 d(30) 10.5001 25.4989 29.2137 10.5001 25.4989 29.2137

[0192] [Table 29] G1 124.2814 G2 -33.4252 G3 27.5610 G4 -35.3300 G5 158.5084

[0193] [Table 30] Face number k A4 A6 A8 A10 A12 6 0.0000 1.24988E-06 -1.66142E-09 -2.63683E-12 4.74801E-15 -2.52742E-18 11 0.0000 8.09226E-06 -2.11044E-08 1.56833E-10 -3.14472E-13 0.00000E+00 12 0.0000 -3.66948E-08 -3.27265E-08 1.51394E-10 -3.94734E-13 0.00000E+00 14 0.0000 -8.83574E-06 -3.75055E-09 -6.86500E-11 -7.24861E-14 3.21734E-16 15 0.0000 -9.08618E-07 7.26658E-09 -6.35024E-11 -1.07811E-13 7.11002E-16 19 0.0000 -8.06138E-06 -1.62754E-08 6.41258E-11 -1.18790E-13 7.65648E-17 20 0.0000 2.73643E-06 -1.38139E-08 2.15996E-11 8.28560E-14 0.00000E+00 23 0.0000 -1.90993E-06 -1.00835E-10 -7.87563E-12 -9.96550E-14 1.21343E-15 24 0.0000 -3.62666E-06 -1.03642E-08 1.32309E-10 -9.06930E-13 3.65180E-15 [Examples]

[0194] (1) Optical configuration of the zoom lens Figure 25 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 7 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0195] The front group consists of, in order from the object side, a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, and a third lens group G3 with positive refractive power. Lens group GB consists of a fourth lens group G4 with positive refractive power. The aperture diaphragm S is positioned adjacent to the fourth lens group G4 on the object side of the fourth lens group G4.

[0196] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a positive meniscus lens L1 with its convex surface facing the object, and a cemented lens formed by joining a negative meniscus lens L2 and a biconvex lens L3, both with their convex surfaces facing the object.

[0197] The second lens group G2 consists of, in order from the object side, a biconcave lens L4, a cemented lens formed by joining a biconcave lens L5 and a positive meniscus lens L6 with its convex surface facing the object side, and a biconcave lens L7.

[0198] The third lens group G3 consists of, in order from the object side, a biconvex lens L8 and a bonded lens formed by joining a biconvex lens L9 and a biconcave lens L10. The biconvex lens L8 is a composite resin type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object.

[0199] The fourth lens group G4 consists of, in order from the object side, a cemented lens formed by joining a biconvex lens L11 and a biconcave lens L12, a biconvex lens L13, a three-element cemented lens formed by joining three lenses: a biconvex lens L14, a biconcave lens L15, and a biconvex lens L16, a biconcave lens L17, and a negative meniscus lens L18 with its convex surface facing the image side. The biconvex lens L14 is a composite resin type aspherical lens in which a composite resin film molded into an aspherical shape is attached to the side surface of the object. Here, the biconvex lens L14, biconcave lens L15, and biconvex lens L16 that make up the three-element cemented lens correspond to the positive lens component P, the biconcave lens L17 corresponds to the negative lens component Nf, and the negative meniscus lens L18 corresponds to the negative lens component Nb.

[0200] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the object, the second lens group G2 moves toward the object, the third lens group G3 moves toward the object, and the fourth lens group G4 moves toward the object.

[0201] Focusing from an object at infinity to an object at close range is achieved by moving the second lens group G2 toward the object in the optical axis direction.

[0202] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 31 shows the surface data of the zoom lens. Table 32 shows the specifications of the zoom lens. Table 33 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distance = 1500 mm). Table 34 shows the focal lengths of each lens group that makes up the zoom lens. Table 35 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 35 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0203] Furthermore, Figures 26 to 28 show the longitudinal aberration diagrams of the zoom lens of Embodiment 7 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0204] [Table 31] Face number rd nd νd Object plane ∞ d(0) 1 99.4643 4.7013 1.48749 70.24 2 1272.3853 0.2000 3 112.1625 1.2000 1.70154 41.24 4 55.6158 7.7447 1.43875 94.94 5 -539.4425 d(5) 6 -247.1969 1.2000 1.74320 49.34 7 158.9413 1.2000 8 -175.1592 0.8000 1.78590 44.20 9 33.2292 3.3929 1.92286 20.88 10 93.2050 2.9489 11 -47.1415 1.0000 1.48749 70.24 12 932.8063 d(12) 13* 52.7618 0.2500 1.51460 49.96 14 56.0006 4.4355 1.88300 40.80 15 -143.9670 0.6191 16 64.0723 7.0000 1.51633 64.14 17 -42.9797 1.0000 1.91082 35.25 18 177.8962 d(18) 19S ∞ 1.0000 20 34.9841 6.0000 1.48749 70.24 21 -205.0838 1.2000 1.92119 23.96 22 48.8700 0.2000 23 30.6099 5.8000 1.51633 64.14 24 -300.7770 13.4699 25* 35.2632 0.2000 1.51460 49.96 26 35.4682 5.7000 1.73800 32.33 27 -20.2725 1.2000 1.83481 42.74 28 28.1903 4.2000 1.67270 32.10 29 -81.7124 1.5384 30 -91.7124 1.0000 1.85150 40.78 31 53.6030 6.8506 32 -17.4556 1.0000 1.59522 67.73 33 -31.2111 d(33) 34 ∞ 2.5000 1.51633 64.14 35 ∞ 1.0000 Image plane ∞

[0205] [Table 32] Wide-angle end, Mid-range, Telephoto end f 72.1000 149.9999 291.4997 FNo. 4.5999 5.0003 6.4501 ω 16.3124 7.9390 4.1494 Y 21.6330 21.6330 21.6330

[0206] [Table 33] Wide-angle end, intermediate, telephoto end, wide-angle end, intermediate, telephoto end d(0) ∞ ∞ ∞ 1340.1438 1316.0004 1284.1438 d(5) 16.5814 35.3224 49.8583 14.1608 31.0032 42.4340 d(12) 23.3990 10.9912 1.5000 25.8196 15.3104 8.9243 d(18) 8.8244 4.5645 2.6913 8.8244 4.5645 2.6913 d(33) 20.5000 42.5702 71.2553 20.5000 42.5702 71.2553

[0207] [Table 34] G1 146.3826 G2 -33.2874 G3 54.5437 G4 205.2293

[0208] [Table 35] Surface number k A4 A6 A8 A10 A12 13 0.0000 -2.39090E-07 9.32745E-10 9.70513E-13 4.73081E-17 0.00000E+00 25 0.0000 -8.30793E-06 -1.62953E-09 -7.69283E-11 5.06491E-13 0.00000E+00 [Examples]

[0209] (1) Optical configuration of the zoom lens Figure 29 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 8 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0210] The front group consists of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, and a fourth lens group G4 with negative refractive power. The fourth lens group G4 corresponds to lens group GF. Lens group GB consists of a fifth lens group G5 with positive refractive power. The aperture diaphragm S is positioned adjacent to the third lens group G3 on the object side.

[0211] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a negative meniscus lens L1 with its convex surface facing the object, a negative meniscus lens L2 with its convex surface facing the object, a biconcave lens L3, and a biconvex lens L4. The negative meniscus lens L2 is a glass molded aspherical lens with aspherical shapes on both sides.

[0212] The second lens group G2 consists of, in order from the object side, a positive meniscus lens L5 with its convex surface facing the object, a negative meniscus lens L6 with its convex surface facing the object, and a biconvex lens L7.

[0213] The third lens group G3 consists of a cemented lens formed by joining a biconvex lens L8 and a negative meniscus lens L9 with its convex surface facing the image side, in that order from the object side.

[0214] The fourth lens group G4 consists of, in order from the object side, a biconcave lens L10, a biconcave lens L11, and a biconvex lens L12.

[0215] The fifth lens group G5 consists of, in order from the object side, a positive meniscus lens L13 with its convex surface facing the object side, a cemented lens formed by joining a biconvex lens L14 and a negative meniscus lens L15 with its convex surface facing the image side, a biconcave lens L16, and a negative meniscus lens L17 with its convex surface facing the image side. The negative meniscus lens L17 is a glass molded aspherical lens with aspherical shapes on both sides. Here, the biconvex lens L14 and the negative meniscus lens L15 that make up the cemented lens correspond to the positive lens component P, the biconcave lens L16 corresponds to the negative lens component Nf, and the negative meniscus lens L17 corresponds to the negative lens component Nb.

[0216] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the image, the second lens group G2 moves towards the object, the third lens group G3 moves towards the object, the fourth lens group G4 moves towards the object, and the fifth lens group G5 moves towards the object.

[0217] Focusing from an object at infinity to an object at close range is achieved by moving the second lens group G2 towards the image along the optical axis.

[0218] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 36 shows the surface data of the zoom lens. Table 37 shows the specifications of the zoom lens. Table 38 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distance = 300 mm). Table 39 shows the focal lengths of each lens group that constitutes the zoom lens. Table 40 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 40 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0219] Furthermore, Figures 30 to 32 show the longitudinal aberration diagrams of the zoom lens of Embodiment 8 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0220] [Table 36] Face number rd nd νd The surface of the object is ∞ d(0). 1 86.9829 2.3000 1.77250 49.60 2 22.3416 4.0024 3* 29.1082 2.0000 1.69350 53.18 4* 15.6610 12.2112 5 -50.5156 1.3000 1.49700 81.61 6 112.7091 0.2000 7 52.1044 4.5487 1.76182 26.52 8 -371.5056 d(8) 9 32.7086 3.6291 1.73800 32.33 10 242.9848 5.3128 11 74.2703 0.8000 1.92119 23.96 12 24.6959 0.9264 13 34.0409 3.7862 1.58913 61.13 14 -240.0248 d(14) 15S ∞ 1.0000 16 26.4280 7.7996 1.59282 68.62 17 -27.5101 1.2000 1.92119 23.96 18 -49.7205 d(18) 19 -78.5563 0.8000 1.89190 37.13 20 52.7476 2.4109 21 -45.3680 0.8000 1.88300 40.80 22 82.7990 0.1500 23 44.1109 3.5532 1.92286 20.88 24 -89.1785 d(24) 25 34.6234 3.1363 1.53775 74.70 26 686.7857 0.1500 27 31.1108 7.6001 1.49700 81.61 28 -17.9379 1.0000 1.90525 35.04 29 -25.7995 0.1500 30 -2576.4922 1.2000 1.77250 49.60 31 37.3239 3.5741 32* -72.6304 2.0000 1.88202 37.22 33* -699.0489 d(33) 34 ∞ 2.5000 1.51680 64.20 35 ∞ 1.0000 Image plane ∞

[0221] [Table 37] Wide-angle end, Mid-range, Telephoto end f 17.5000 21.0000 34.0000 FNo. 2.9001 2.8999 2.9000 ω 51.9992 45.7539 31.8248 Y 21.6330 21.6330 21.6330

[0222] [Table 38] Wide-angle end, intermediate, telephoto end, wide-angle end, intermediate, telephoto end d(0) ∞ ∞ ∞ 160.0000 160.5000 169.0353 d(8) 25.0787 15.9198 1.5000 28.0132 18.8906 4.6344 d(14) 6.8158 12.6052 4.6344 3.8814 9.6344 1.5000 d(18) 1.5000 2.3549 4.1434 1.5000 2.3549 4.1434 d(24) 6.4555 3.9935 1.3000 6.4555 3.9935 1.3000 d(33) 19.1092 23.5857 38.3460 19.1092 23.5857 38.3460

[0223] [Table 39] G1 -23.6162 G2 64.6409 G3 35.5085 G4 -38.9440 G5 61.5671

[0224] [Table 40] Surface number k A4 A6 A8 A10 A12 3 -2.1933 2.53384E-05 -1.07903E-07 2.91024E-10 -3.92272E-13 2.05544E-16 4 -0.4294 8.66936E-06 -1.46839E-07 1.24836E-10 4.06332E-13 -1.55239E-15 32 0.0000 -1.45788E-04 4.68549E-07 4.22206E-10 -8.24313E-13 -6.36887E-15 33 0.0000 -1.01420E-04 6.19196E-07 -3.68610E-10 -1.05117E-12 -1.77846E-16 [Examples]

[0225] (1) Optical configuration of the zoom lens Figure 33 is a cross-sectional view of the lens configuration of the zoom lens of Embodiment 9 of the present invention when it is focused at infinity at the wide-angle end. The zoom lens consists of a front group and lens group GB, in order from the object side, which have a positive refractive power as a whole.

[0226] The front group consists of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, and a third lens group G3 with negative refractive power. The third lens group G3 corresponds to lens group GF. Lens group GB consists of a fourth lens group G4 with negative refractive power. The aperture diaphragm S is located within the second lens group G2.

[0227] The configuration of each lens group is described below. The first lens group G1 consists of, in order from the object side, a negative meniscus lens L1 with its convex surface facing the object, a negative meniscus lens L2 with its convex surface facing the object, a biconcave lens L3, and a biconvex lens L4. The negative meniscus lens L2 is a glass molded aspherical lens with aspherical shapes on both sides.

[0228] The second lens group G2 consists of, in order from the object side, a cemented lens formed by joining a negative meniscus lens L5 and a biconvex lens L6 with their convex surfaces facing the object side, a biconvex lens L7, and a cemented lens formed by joining a negative meniscus lens L8 and a biconvex lens L9 with their convex surfaces facing the object side. The negative meniscus lens L5 is a glass molded aspherical lens with an aspherical shape on the object side.

[0229] The third lens group G3 consists of a negative meniscus lens L10 with its convex surface facing the object.

[0230] The fourth lens group G4 consists of, in order from the object side, a biconvex lens L11, a biconcave lens L12, and a negative meniscus lens L13 with its convex surface facing the image side. The negative meniscus lens L13 is a glass-molded aspherical lens with aspherical shapes on both sides. Here, the biconvex lens L11 corresponds to the positive lens component P, the biconcave lens L12 corresponds to the negative lens component Nf, and the negative meniscus lens L13 corresponds to the negative lens component Nb.

[0231] When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves towards the image, the second lens group G2 moves towards the object, the third lens group G3 moves towards the object, and the fourth lens group G4 moves towards the object.

[0232] Focusing from an object at infinity to an object at close range is achieved by moving the third lens group G3 towards the image along the optical axis.

[0233] (2) Numerical Examples Next, we will describe a numerical example in which the specific values ​​of the zoom lens are applied. Table 41 shows the surface data of the zoom lens. Table 42 shows the specifications of the zoom lens. Table 43 shows the variable spacing on the optical axis of the zoom lens when focused at infinity and when focused on a close object (shooting distance = 280 mm). Table 44 shows the focal lengths of each lens group that constitutes the zoom lens. Table 45 shows the aspheric coefficients of each aspheric surface. Note that aspheric coefficients not shown in Table 45 are 0.00. Also, Table 46 shows the values ​​of conditional equations (1) to (8) and the values ​​used in the calculation of conditional equations (1) to (8).

[0234] Furthermore, Figures 34 to 36 show the longitudinal aberration diagrams of the zoom lens of Embodiment 9 at the wide-angle end, intermediate focal length position, and telephoto end when focused at infinity, respectively.

[0235] [Table 41] Face number rd nd νd Object plane ∞ d(0) 1 60.0000 1.8000 1.72916 54.67 2 17.6846 3.4244 3* 32.7014 1.7000 1.69350 53.18 4* 16.4714 9.7187 5 -39.4214 1.0000 1.49700 81.61 6 70.1772 0.1500 7 35.7604 5.4096 1.62004 36.26 8 -72.8884 d(8) 9* 40.9225 0.8000 1.86100 37.10 10 17.9883 4.3722 1.61772 49.81 11 -123.5638 7.9809 12S ∞ 1.0000 13 24.8970 4.7951 1.53775 74.70 14 -64.3209 0.1500 15 23.9008 0.8000 1.88300 40.80 16 11.4921 6.8076 1.49700 81.61 17 -40.4592 d(17) 18 351.1231 0.7000 1.48749 70.24 19 15.9630 d(19) 20 32.6679 5.8277 1.51823 58.90 21 -16.2745 0.1500 22 -21.5991 0.8000 1.73400 51.47 23 157.9588 2.8368 24* -56.5696 1.3000 1.88202 37.22 25* -223.9375 d(25) 26 ∞ 2.5000 1.51680 64.20 27 ∞ 1.0000

[0236] [Table 42] Wide-angle end, Mid-range, Telephoto end f 17.5000 22.0000 27.5000 FNo. 2.9001 2.9001 2.9001 ω 52.4786 44.6024 37.5020 Y 21.6330 21.6330 21.6330

[0237] [Table 43] Wide-angle end, intermediate, telephoto end, wide-angle end, intermediate, telephoto end d(0) ∞ ∞ ∞ 177.1524 181.7800 184.3366 d(8) 16.9527 8.2625 1.2000 16.9527 8.2625 1.2000 d(17) 1.5000 1.9253 2.5717 2.0988 2.7204 3.6301 d(19) 5.7254 6.1609 6.1329 5.1266 5.3658 5.0744 d(25) 13.6467 16.8485 20.7360 13.6467 16.8485 20.7360

[0238] [Table 44] G1 -25.7028 G2 21.0442 G3 -34.3283 G4 -1498.9817

[0239] [Table 45] Surface number k A4 A6 A8 A10 A12 3 2.3554 5.63471E-05 -3.26682E-07 1.00072E-09 -1.17701E-12 -1.88438E-15 4 0.1008 5.42937E-05 -3.06529E-07 -3.63644E-10 8.32643E-12 -3.46288E-14 9 0.0000 -9.28259E-06 -1.77863E-08 1.08966E-10 -3.75312E-13 0.00000E+00 24 0.0000 -2.38929E-04 1.22551E-06 -8.20489E-09 4.12193E-11 -1.28092E-13 25 0.0000 -1.94636E-04 1.35828E-06 -7.50619E-09 3.21968E-11 -6.85586E-14

[0240] [Table 46] Example 1 Example 2 Example 3 Example 4 Example 5 Conditional expression (1) (RNf+RNb) / (RNf-RNb) 0.311 0.765 0.866 1.204 0.504 Conditional expression (2)βFBt / βFBw 1.568 1.370 1.589 1.852 1.288 Conditional expression (3) BFw / Y 0.786 0.886 0.786 0.786 0.867 Conditional expression (4) fP / Y 1.436 1.187 1.363 1.211 1.637 Conditional expression (5) |fN| / Y 0.973 0.782 1.032 1.349 1.473 Conditional expression (6) RP / fw 1.271 1.395 1.278 1.393 1.138 Conditional expression (7) fNf / fNb 0.846 0.474 1.419 1.466 1.002 Conditional expression (8) νP 32.09 33.79 38.02 26.60 43.70 RNf 40.075 120.199 340.851 -352.621 80.926 RNb -21.055 -16.000 -24.453 -32.694 -26.723 βFBt 3.061 2.478 2.991 3.817 2.689 βFBw 1.952 1.808 1.883 2.061 2.088 BFw 17.000 19.157 17.000 17.000 18.751 Y 21.633 21.633 21.633 21.633 21.633 fP 31.062 25.674 29.476 26.205 35.410 fN -21.045 -16.926 -22.335 -29.190 -31.874 RP 36.602 40.174 36.802 40.131 40.986 fNf -41.530 -26.547 -56.585 -74.113 -66.501 fNb -49.078 -56.038 -39.864 -50.559 -66.395

[0241] [Table 47] Example 6 Example 7 Example 8 Example 9 Conditional expression (1)(RNf+RNb) / (RNf-RNb) 0.337 0.509 -0.321 0.473 Condition (2) βFBt / βFBw 1.320 - 1.110 1.134 Conditional expression (3)BFw / Y 0.657 1.109 1.045 0.793 Conditional expression (4) fP / Y 1.687 2.500 1.687 1.010 Conditional expression (5)|fN| / Y 1.680 1.096 1.415 0.895 Conditional expression (6)RP / fw 1.746 0.489 1.778 1.867 Conditional expression (7) fNf / fNb 1.197 0.579 0.517 0.300 Conditional expression (8) νP 42.80 32.10 81.61 58.90 RNf 45.784 53.603 37.324 157.959 RNb -22.709 -17.456 -72.630 -56.570 βFBt 2.227 - 1.577 2.077 βFBw 1.687 - 1.421 1.832 BFw 14.000 24.000 22.609 17.147 Y 21.300 21.633 21.633 21.633 fP 35.938 54.083 36.503 21.850 fN -35.778 -23.713 -30.622 -19.356 RP 43.124 35.263 31.111 32.668 fNf -82.057 -39.605 -47.616 -25.838 fNb -68.539 -68.397 -92.031 -86.128

[0242] Furthermore, the zoom lens according to the present invention is composed of a front group having a positive refractive power as a whole, arranged in order from the object side, and a lens group GB arranged on the image side of the front group, and is a zoom lens that changes magnification by changing the distance between adjacent lens groups on the optical axis. The aforementioned front group has at least three lens groups, The aforementioned front group is equipped with a negative lens group GF on its image side, When a single lens or a cemented lens is referred to as a lens component, the lens group GB has, in order from the image side, a negative lens component Nb, a negative lens component Nf, and a positive lens component P. The object side surface of the negative lens component Nb is concave, The aforementioned positive lens component P has a biconvex shape, Focusing is performed by moving the negative lens group GF along the optical axis. This also includes zoom lenses that satisfy the following conditional equation. (3) 0.3 ≤ BFw / Y ≤ 1.2 (4) 0.5 ≤ fP / Y ≤ 1.436 however, BFw: Back focus of the zoom lens at the wide-angle end. Y: Maximum image height of the zoom lens fP: Focal length of the positive lens component P. [Industrial applicability]

[0243] According to the present invention, it is possible to provide a zoom lens suitable for digital still cameras with a short flange back, which is generally compact, allows for easy reduction of the diameter of the final lens group, and is high-performance, as well as an imaging device having said zoom lens. [Explanation of symbols]

[0244] G1...First lens group G2...Second lens group G3...Third lens group G4...4th lens group G5...5th lens group G6...6th lens group G7...7th lens group GF... Lens group GF GB... Lens group GB S...Opening diaphragm IP...image plane CG...cover glass FNo.···F-number ω...Half angle of view

Claims

1. A zoom lens that, starting from the object side, consists of a front group having a positive refractive power as a whole, and a lens group GB positioned on the image side of the front group, and magnifies by changing the distance between adjacent lens groups along the optical axis, The aforementioned front group has at least four lens groups, The aforementioned front group is equipped with a negative lens group GF on its image side, When a single lens or a cemented lens is referred to as a lens component, the lens group GB has, in order from the image side, a negative lens component Nb, a negative lens component Nf, and a positive lens component P. The aforementioned positive lens component P has a biconvex shape, Focusing is performed by moving the negative lens group GF along the optical axis. A zoom lens characterized by satisfying the following condition. (3-1) 0.3 ≦ BFw / Y ≦ 1.2 (7-1) 0.2 ≦ fNf / fNb ≦ 1.002 however, BFw: Back focus of the zoom lens at the wide-angle end. Y: Maximum image height of the zoom lens fNf: Focal length of the negative lens component Nf fNb: Focal length of the negative lens component Nb

2. A zoom lens according to claim 1 that satisfies the following condition. (2) 1.1 ≦ βFBt / βFBw ≦ 2.5 however, βFBt: Combined horizontal magnification of the negative lens group GF and the lens group GB at the telephoto end. βFBw: Combined horizontal magnification of the negative lens group GF and the lens group GB at the wide-angle end.

3. The zoom lens according to claim 1 or claim 2, wherein the negative lens component Nb has a negative meniscus shape with a convex surface facing the image side.

4. The zoom lens according to any one of claims 1 to 3, characterized in that the air lens formed from the image side of the positive lens component P and the object side of the negative lens component Nf is biconcave or has a negative meniscus shape with the concave surface facing the object side.

5. A zoom lens according to any one of claims 1 to 4, satisfying the following conditional expression. (4) 0.5 ≦ fP / Y ≦ 2.7 however, fP: Focal length of the positive lens component P. Y: Maximum image height of the zoom lens

6. A zoom lens according to any one of claims 1 to 5, satisfying the following conditional expression. (5) 0.4 ≦ |fN| / Y ≦ 2.7 however, fN: The combined focal length of the negative lens component Nf and the negative lens component Nb. Y: Maximum image height of the zoom lens

7. The zoom lens according to any one of claims 1 to 6, characterized in that, when zooming, the lens group positioned closest to the object in the front group moves along the optical axis.

8. The zoom lens according to any one of claims 1 to 7, wherein the lens group positioned closest to the object in the front group has a positive refractive power.

9. An imaging device comprising a zoom lens according to any one of claims 1 to 8, and an image sensor on the image plane side of the zoom lens that converts the optical image formed by the zoom lens into an electrical signal.

Images