Lens device and imaging device having the same

Abstract

The objective is to provide a compact lens device with a wide field of view. [Solution] The lens device of the present invention comprises an optical system consisting of a first lens group having negative refractive power and a rear lens group having positive refractive power, arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, the rear lens group includes one or more lens groups and an aperture diaphragm, and a focus group consisting of one or more lens groups included in the rear lens group moves in the optical axis direction during focusing, and satisfies the condition that ωw > 85 when the half-angle of view at infinity focus at the wide-angle end is ωw(°), wherein the lens device comprises a holding member for holding the focus group and a driving member for moving the holding member in the optical axis direction, wherein the driving member and the aperture diaphragm overlap in a direction perpendicular to the optical axis.

Description

[Technical Field]

[0001] The present invention relates to a lens device and an imaging device having the same, and is suitable for imaging devices using solid-state image sensors such as digital still cameras, video cameras, broadcast cameras, surveillance cameras, and in-vehicle cameras, or imaging devices such as cameras using silver halide photographic film. [Background technology]

[0002] Lens devices used in imaging devices are required to have a wide field of view while possessing good optical characteristics. As a wide-field-of-view lens device, a negative-lead type lens device is known, such as the one disclosed in Patent Document 1, in which the lens group with the most negative refractive power is positioned closest to the object. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-166234 [Overview of the project] [Problems that the invention aims to solve]

[0004] Wide-angle lens systems tend to be larger overall; therefore, in order to miniaturize wide-angle lens systems, it is necessary to appropriately arrange each component that makes up the focusing mechanism. [Means for solving the problem]

[0005] A lens device as one aspect of the present invention comprises an optical system consisting of a first lens group having negative refractive power and a rear lens group having positive refractive power, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, the rear lens group includes one or more lens groups and an aperture diaphragm, and a focus group consisting of one or more lens groups included in the rear lens group moves in the optical axis direction during focusing, and satisfies the condition ωw > 85 when the half-angle of view at infinity focus at the wide-angle end is ωw(°), wherein the lens device comprises a holding member for holding the focus group and a driving member for moving the holding member in the optical axis direction, and the driving member and the aperture diaphragm overlap in a direction perpendicular to the optical axis. [Effects of the Invention]

[0006] This allows us to provide a compact lens device with a wide field of view. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the lens device of Example 1 [Figure 2] Aberration diagram of the lens device in Example 1 [Figure 3] Cross-sectional view of the lens device of Example 2 [Figure 4] Aberration diagram of the lens device in Example 2 [Figure 5] Cross-sectional view of the lens device of Example 3 [Figure 6] Aberration diagram of the lens device in Example 3 [Figure 7] Cross-sectional view of the lens device of Example 4 [Figure 8] Aberration diagram of the lens device in Example 4 [Figure 9] Cross-sectional view of the lens device of Example 5 [Figure 10] Aberration diagram of the lens device in Example 5 [Figure 11] Cross-sectional view of the lens device of Example 6 [Figure 12] Aberration diagram of the lens device of Example 6 [Figure 13] Schematic diagram of an imaging device [Figure 14] Cross-sectional view showing the lens barrel of each embodiment [Figure 15] View showing the shape of the rear fixed barrel in which the filter barrel is incorporated [Figure 16] Cross-sectional view showing the member arrangement around the drive member in the comparative example [Figure 17] Cross-sectional view showing miniaturization in the optical axis direction due to the arrangement around the drive member in the present embodiment [Figure 18] Cross-sectional view showing miniaturization in the optical axis direction and the radial direction due to the arrangement around the drive member in the present embodiment [Figure 19] Cross-sectional view showing miniaturization in the radial direction due to the arrangement around the drive member in the present embodiment [Figure 20] Cross-sectional view showing miniaturization in the optical axis direction due to the arrangement of the drive member and the control board in the present embodiment [Figure 21] Cross-sectional view showing the arrangement of the aperture stop, focus barrel, control board, and filter barrel

Mode for Carrying Out the Invention

[0008] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the drawings. Note that each drawing may be drawn at a scale different from the actual for convenience. Also, in each drawing, the same members are denoted by the same reference numerals, and redundant explanations are omitted.

[0009] Figs. 1, 3, 5, 7, 9, and 11 show cross-sectional views of the lens device L0 at the wide-angle end of Examples 1 to 6 in a state of being focused at infinity. The lens device L0 of each example is used in an optical device including an imaging device such as a digital video camera, a digital still camera, a broadcast camera, a silver halide film camera, a surveillance camera, or an interchangeable lens. In each cross-sectional view, the left side is the object side, and the right side is the image side.

[0010] The lens device L0 in each embodiment is composed of multiple lens groups. In this specification, a lens group refers to a collection of one or more lenses that move together as a single unit during zooming. In the lens device L0 of each embodiment, the distance between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end.

[0011] In each cross-sectional view, Li represents the i-th lens group (where i is a natural number) from the object side among the lens groups included in the lens device L0. LR is the rear group and includes all lenses and lens groups positioned closer to the image than the first lens group L1.

[0012] In each cross-sectional view, SP is the aperture diaphragm. In each cross-sectional view, IP is the image plane, and when the lens device L0 of each embodiment is used as the photographic optical system of a digital still camera or digital video camera, the image plane of a solid-state image sensor such as a CCD sensor or a photoelectric conversion element such as a CMOS sensor is arranged on the image plane IP. Furthermore, when the lens device L0 of each embodiment is used as the photographic optical system of a silver halide film camera, a photosensitive surface corresponding to the film plane is arranged on the image plane IP.

[0013] The solid arrows shown in each lens cross-sectional diagram represent a simplified representation of the movement trajectory of each lens group when zooming from the wide-angle end to the telephoto end. In this specification, the wide-angle end and telephoto end refer to the zoom positions when each lens group is located at the ends of the range in which it can move along the optical axis. The dashed arrows shown in each lens cross-sectional diagram represent a simplified representation of the movement trajectory of the focus group LF when focusing from infinity to close range, as it moves relative to the image plane.

[0014] The lens apparatus L0 of each embodiment consists of a first lens group L1 with negative refractive power, arranged sequentially from the object side to the image side, and a rear group LR including one or more lens groups. The rear group LR includes all lens groups positioned closer to the image side than the first lens group L1. In the lens apparatus L0 of each embodiment, an optical element with substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be placed between the lens positioned closest to the image and the imaging plane.

[0015] Figures 2, 4, 6, 8, 10, and 12 are aberration diagrams of the lens apparatus L0 of Examples 1 to 6. Each aberration diagram represents the aberration of each example when focused at infinity, with (A) being at the wide-angle end, (B) at the intermediate zoom position, and (C) at the telephoto end.

[0016] In the spherical aberration diagram, Fno is the F-number, and the solid line shows the amount of spherical aberration for the d-line (wavelength 587.6 nm) and the dashed g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS shows the amount of astigmatism at the sagittal image plane, and ΔM shows the amount of astigmatism at the meridional image plane. In the distortion diagram, the solid line shows the amount of distortion for the d-line. In the chromatic aberration diagram, the dashed line shows the amount of chromatic aberration at the g-line. In each aberration diagram, ω is the half-angle of view (°), which is the angle of view calculated paraxially.

[0017] In the lens apparatus L0 of each embodiment, the projection method of Embodiments 1 to 3 is an equi-angle projection method expressed by the equation Y = f·θ. The projection method of Embodiments 4 to 6 is an equi-solid angle projection method expressed by the equation Y = 2·f·sin(θ / 2). Here, f represents the focal length of the entire lens apparatus L0 system, and θ represents the angle of incidence of the light ray. Note that the projection method in the lens apparatus of each embodiment is not limited to equi-angle projection or equi-solid angle projection, and other projection methods may be used.

[0018] Figure 14 is a cross-sectional view of the lens barrel in this embodiment. The line indicated by XX in the figure represents the optical axis. In Figure 14, the mount 101 is a component fixed to a camera body (not shown). The guide tube 102 is integrally fixed to the mount 101 together with the rear fixing tube 131 and the intermediate fixing tube 132. A cam ring 104 is held on the outer circumference of the guide tube 102 so as to be freely rotatable around the optical axis. The cam ring 104 is connected to a zoom ring 105, which is freely rotatable on the outer circumference of the intermediate fixing tube 132, by a key member (not shown), and is configured to rotate together when the zoom ring 105 is operated from the outside.

[0019] The zoom sensor 106 is attached to the intermediate fixed cylinder 132 and is a sensor that can electrically detect the rotation angle of the zoom ring 105. The zoom sensor 106 is electrically connected to the control board 107 and transmits focal length information during zooming to the control circuit.

[0020] The control board 107 has a contact block 108 that is electrically connected to it, and it communicates with the camera body (not shown) and supplies power to it.

[0021] The first lens group L1 is held in the first lens barrel 111, which is in contact with the guide tube 102.

[0022] The second lens group L2 is held in the second lens barrel 112 and is in contact with the second lens base barrel 119.

[0023] The third lens group L3 is held in the third lens barrel 113 and is in contact with the rear lens base barrel 120.

[0024] The fourth lens group L4 is held in the fourth lens barrel 114 and is in contact with the rear lens base barrel 120.

[0025] The rear group base barrel 120 is a cylindrical member in the focusing mechanism, holds the aperture diaphragm 121, and is electrically connected to the control board 107.

[0026] The fifth lens group L5 is held in the fifth lens barrel 115, which is held by a guide bar (not shown) so as to be able to move relative to the rear lens base barrel 120 in the optical axis direction.

[0027] In one example of this embodiment, the fifth lens group L5 is a lens for focus adjustment and is driven in the optical axis direction via a rack 123 by a drive member 122 connected to a lead screw held in the rear group base barrel 120. That is, the rack 123 is a transmission member that transmits the driving force of the drive member 122 to a holding member described later. The drive member 122 is electrically connected to the control board 107 by a flexible printed circuit board (not shown). The drive member 122 is a member having a mechanism capable of driving the holding member, such as a stepping motor to which a lead screw is connected, an ultrasonic motor, or a voice coil motor.

[0028] The second group tube 119 and the rear group base tube 120 are telescope tubes that move during zooming, and cam followers (not shown) are fixed to the second group tube 119 and the rear group base tube 120. Each cam follower engages with a straight groove provided in the guide tube 102 and a cam groove provided in the cam ring 104, and is configured to move in a straight line in the optical axis direction by rotating the cam ring 104.

[0029] Furthermore, the 5-group lens barrel 115, which is a holding member for holding the LF focus group for focus adjustment, is fixed to the rear-group base lens barrel 120 and moves together with the rear-group base lens barrel 120 during zooming, while being driven in the optical axis direction by the drive member 122.

[0030] The filter 110 is held in the filter barrel 117 and is incorporated between the 6-group lens barrel 116 and the mount 101. As shown in Figure 15, the rear fixing cylinder 131 has an opening H so that the filter barrel 117 can be incorporated. The filter 110 is an optical component such as a drop-in filter. The filter barrel 117 is a filter holding member.

[0031] Next, we will describe the characteristic configuration of the lens device L0 in each embodiment.

[0032] The lens apparatus L0 in each embodiment is a negative-lead type lens apparatus in which the first lens group L1 has a negative refractive power. It is desirable that the lens G1 closest to the object among the lenses included in the first lens group L1 be fixed to the image plane during zooming. This prevents the overall optical length of the lens apparatus L0 from changing during zooming, thereby improving the robustness of the lens apparatus L0.

[0033] When ωw(°) is the half-angle of view at infinity focus at the wide-angle end of the lens device L0, satisfying the condition ωw > 85 allows for obtaining the wide angle of view necessary for a fisheye lens device or an ultra-wide-angle lens device. Furthermore, to obtain a sufficiently wide angle of view for a fisheye lens device or an ultra-wide-angle lens device, it is more preferable to satisfy the condition ωw > 92. Moreover, it is even more preferable to satisfy the condition ωw > 94.

[0034] Furthermore, in the lens device L0 of each embodiment, each component constituting the focusing mechanism is appropriately arranged.

[0035] Figure 16 is a diagram showing the arrangement around the drive member 122 as a comparative example. Consider the case where the drive member 122 and the 5-group lens barrel 115, which is a holding member for focus adjustment, are arranged on the image side of the aperture diaphragm 121, as in this embodiment. The drive member 122 requires at least space in the optical axis direction for the motor section, the rack 123, and space to secure the stroke during focusing. As shown in Figure 16, if the drive member 122 is arranged on the image side of the aperture diaphragm 121, a large space must be secured in the optical axis direction on the image side of the aperture diaphragm 121, which results in a larger lens barrel.

[0036] Figure 17 is an arrangement diagram of the drive member 122 in this embodiment. As shown in Figure 17, the components are arranged so that the drive member 122 overlaps with the aperture diaphragm 121 in a direction perpendicular to the optical axis. By adopting this configuration, the overall length of the lens barrel in the optical axis direction can be shortened while securing space for the drive member 122, thereby miniaturizing the lens device L0. In this disclosure, "the drive member 122 and the aperture diaphragm 121 overlapping in a direction perpendicular to the optical axis" means that when the drive member 122 and the aperture diaphragm 121 are viewed from a direction perpendicular to the optical axis, at least a part of the aperture diaphragm 121 is hidden by the drive member 122. Furthermore, the drive member 122 and the aperture diaphragm may or may not be in contact.

[0037] With the above configuration, a compact lens device with a wide field of view can be obtained.

[0038] Next, we will describe the conditions that are preferable for the lens apparatus L0 of each embodiment to satisfy.

[0039] The lens device L0 of each embodiment preferably satisfies at least one of the following conditional equations (1) to (12). However, in each conditional equation, the numerical values ​​are expressed as follows.

[0040] Let fL1 be the focal length of the first lens group L1, and fL2 be the focal length of the second lens group L2.

[0041] Let fw be the focal length of lens device L0 at the wide-angle end.

[0042] Let fG1 be the focal length of lens G1, which is positioned closest to the object in the first lens group L1, and fG2 be the focal length of lens G2, which is positioned adjacent to lens G1 on the image side.

[0043] Let the focal length of the LF group be fLF.

[0044] Let fLRw be the focal length of the rear group LR at the wide-angle end of the lens device L0.

[0045] Let Skw be the back focus of lens device L0 at the wide-angle end.

[0046] DSPw is defined as the distance along the optical axis from the aperture diaphragm SP of the lens device L0 at the wide-angle end to the lens surface closest to the image.

[0047] Let ndG1 be the refractive index of the material of lens G1, the lens closest to the object in the first lens group L1, with respect to the d line.

[0048] In the first lens group L1, of the lens G1 closest to the object, let R1 be the radius of curvature of the object-side lens surface and R2 be the radius of curvature of the image-side lens surface.

[0049] Let Yta be the maximum image height that can be captured at the telephoto end of the lens device L0, and Ywa be the maximum image height that can be captured at the wide-angle end. -3.0 <fL1 / fw<-1.7 (1) -5.0 < |fL2| / fL1 < -1.1 (2) 1.4 <fG1 / fL1<3.0 (3) 0.40 <fG1 / fG2<1.60 (4) 3.5 <fLF / fw<15.0 (5) -4.1 <fLF / fL1<-1.8 (6) -1.30 <fL1 / fLRw<-0.55 (7) 2.0 <Skw / fw<6.0 (8) 0.40 <DSPw / Skw<1.00 (9) 1.65 <ndG1<2.20 (10) 1.3 < (R1 + R2) / (R1 - R2) < 3.0 (11) 1.5 <Yta / Ywa<3.0 (12) Here, we will explain the technical meaning of the aforementioned conditional expressions (1) through (12).

[0050] Condition (1) defines the ratio of the focal length fL1 of the first lens group L1 to the focal length fw of the lens device L0 at the wide-angle end. By satisfying condition (1), the focal length fL1 of the first lens group L1 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fL1 of the first lens group L1 becomes too long, falling below the lower limit of condition (1), the first lens group L1 becomes large, making it difficult to miniaturize the lens device L0. If the focal length fL1 of the first lens group L1 becomes too short, exceeding the upper limit of condition (1), the image height change due to coma aberration becomes large, making it difficult to correct field curvature and astigmatism.

[0051] Condition (2) specifies the ratio of the focal length fL2 of the second lens group L2 to the focal length fL1 of the first lens group L1. By satisfying condition (2), the focal lengths fL1 of the first lens group L1 and fL2 of the second lens group L2 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fL1 of the first lens group L1 becomes too short, falling below the lower limit of condition (2), the image height change due to off-axis coma aberration becomes large, making it difficult to correct field curvature and astigmatism. If the focal length fL1 of the first lens group L1 becomes too long, exceeding the upper limit of condition (2), the first lens group L1 becomes large, making it difficult to miniaturize the lens device L0.

[0052] Condition (3) specifies the ratio of the focal length fG1 of the lens G1 closest to the object in the first lens group L1 to the focal length fL1 of the first lens group L1. By satisfying condition (3), the focal length fG1 of lens G1 can be appropriately positioned, thereby effectively correcting distortion, chromatic aberration, and field curvature. If the focal length fG1 of lens G1 becomes too short, falling below the lower limit of condition (3), it becomes difficult to correct field curvature and distortion. If the focal length fG1 of lens G1 becomes too long, exceeding the upper limit of condition (3), the first lens group L1 becomes larger, making it difficult to miniaturize the lens device L0.

[0053] Conditional equation (4) specifies the ratio of the focal length fG1 of the lens G1 closest to the object in the first lens group L1 to the focal length fG2 of the lens G2 positioned adjacent to the image side of lens G1. Two negative lenses are arranged in order from the object side to achieve a wide-angle view. If the focal length fG1 of lens G1 becomes too short, falling below the lower limit of conditional equation (4), it becomes difficult to correct field curvature and distortion. If the focal length fG1 of lens G1 becomes too long, exceeding the upper limit of conditional equation (4), lens G1 and the first lens group L1 become large, making it difficult to miniaturize the lens device L0.

[0054] Condition (5) defines the ratio of the focal length fLF of the focusing group LF to the focal length fw of the lens device L0 at the wide-angle end. If the focal length fLF of the focusing group LF becomes too short, falling below the lower limit of condition (5), it becomes difficult to suppress fluctuations in various aberrations, including spherical aberration, associated with focusing. If the focal length fLF of the focusing group LF becomes too long, exceeding the upper limit of condition (5), the amount of movement associated with focusing becomes large, making it difficult to miniaturize the lens device L0.

[0055] Condition (6) specifies the ratio of the focal length fLF of the focusing group LF to the focal length fL1 of the first lens group L1. If the focal length fLF of the focusing group LF becomes too long, below the lower limit of condition (6), the amount of movement required for focusing becomes long, making it difficult to miniaturize the optical system. If the focal length fLF of the focusing group LF becomes too short, above the upper limit of condition (6), it becomes difficult to suppress fluctuations in various aberrations, including spherical aberration, that occur during focusing.

[0056] Condition (7) specifies the ratio of the focal length fL1 of the first lens group L1 to the focal length fLRw of the rear group LR at the wide-angle end. If the focal length fL1 of the first lens group L1 becomes too long, falling below the lower limit of condition (7), the convergence effect in the rear group LR becomes large, causing strong lateral chromatic aberration and axial chromatic aberration, thus degrading optical performance. If the focal length fL1 of the first lens group L1 becomes too short, exceeding the upper limit of condition (7), it becomes difficult to correct spherical aberration and coma aberration in the rear group LR.

[0057] Conditional equation (8) defines the ratio of the back focus Skw at the wide-angle end to the focal length fw of the lens device L0 at the wide-angle end. If the back focus Skw becomes too short, falling below the lower limit of conditional equation (8), it becomes difficult to place optical elements such as a low-pass filter near the image sensor that converts the optical image formed by this lens device L0 into photoelectric form. If the back focus Skw becomes too long, exceeding the upper limit of conditional equation (8), the total optical length of the lens device L0 at the wide-angle end becomes long, making miniaturization difficult.

[0058] Conditional equation (9) defines the ratio of the distance DSPw on the optical axis from the aperture diaphragm SP to the image-side lens surface at the wide-angle end to the back focus Skw at the wide-angle end. If the distance DSPw on the optical axis from the aperture diaphragm SP to the image-side lens surface falls below the lower limit of conditional equation (9) and becomes too short, it becomes difficult to position the focus group LF. If the back focus Skw exceeds the upper limit of conditional equation (9) and becomes too short, the overall optical length of the lens device L0 at the wide-angle end becomes long, making miniaturization difficult.

[0059] Condition (10) defines the refractive index ndG1 of the material of lens G1, which is closest to the object in the first lens group L1, with respect to the d line. By satisfying condition (10), the refractive index of the material of lens G1 can be set to an appropriate range, thereby enabling good correction of chromatic aberration.

[0060] If the refractive index ndG1 of the lens G1 closest to the object becomes too small, below the lower limit of condition (10), it becomes necessary to weaken the refractive power of the negative lens to correct the field curvature. As a result, the back focus increases, making it difficult to miniaturize the lens device L0. If the refractive index ndG1 of the lens G1 closest to the object becomes too large, it becomes necessary to select a highly dispersed material with a small Abbe number, making it difficult to adequately correct distortion and chromatic aberration.

[0061] Condition (11) defines the shape of the object-side lens G1 in the first lens group L1. R1 is the radius of curvature of the object-side lens surface of the object-side lens G1, and R2 is the radius of curvature of the image-side lens surface of the object-side lens G1. By satisfying condition (11), if the value falls below the lower limit of condition (11), the refractive power of the object-side lens G1 becomes too strong, making it difficult to obtain high optical performance. If the value exceeds the upper limit of condition (11), the refractive power of the object-side lens G1 becomes too weak, making it difficult to obtain a wide field of view.

[0062] Conditional equation (12) defines the ratio of the maximum image height Yta at the telephoto end to the maximum image height Ywa at the wide-angle end. The maximum image height is the distance between the optical axis and the image point where the peripheral illumination is 15% among the image points that can be photographed. If the maximum image height at the telephoto end becomes too small, falling below the lower limit of conditional equation (12), it becomes difficult to make the lens device L0 a wide-angle lens device that includes everything from circular fisheye to diagonal fisheye.

[0063] If the maximum image height at the telephoto end becomes too large, exceeding the upper limit of condition (12), the amount of movement of each lens group or the refractive power of each lens group during zooming becomes large, making it difficult to suppress aberrations during zooming.

[0064] Furthermore, it is preferable that the numerical ranges of conditional expressions (1) to (12) be the numerical ranges of the following conditional expressions (1a) to (12a). -2.6 <fL1 / fw<-1.9 (1a) -3.6 < |fL2| / fL1 < -1.6 (2a) 1.6 <fG1 / fL1<2.7 (3a) 0.47 <fG1 / fG2<1.30 (4a) 4.4 <fLF / fw<10.0 (5a) -3.9 <fLF / fL1<-2.1 (6a) -1.20 <fL1 / fLRw<-0.60 (7a) 4.0 <Skw / fw<5.3 (8a) 0.50 <DSPw / Skw<0.81 (9a) 1.66 <ndG1<1.96(10a) 1.5 < (R1 + R2) / (R1 - R2) < 2.7 (11a) 1.8 <Yta / Ywa<2.3 (12a) Furthermore, it is even more preferable that the numerical ranges of conditional expressions (1) to (12) be the numerical ranges of the following conditional expressions (1b) to (12b). -2.5 <fL1 / fw<-2.0 (1b) -3.4 < |fL2| / fL1 < -1.7 (2b) 1.7 <fG1 / fL1<2.6 (3b) 0.48 <fG1 / fG2<1.20 (4b) 4.6 <fLF / fw<8.0 (5b) -3.7 <fLF / fL1<-2.2 (6b) -1.10 <fL1 / fLRw<-0.63 (7b) 4.3 <Skw / fw<4.9 (8b) 0.53 <DSPw / Skw<0.79 (9b) 1.71 <ndG1<1.91 (10b) 1.7 < (R1 + R2) / (R1 - R2) < 2.5 (11b) 1.9 <Yta / Ywa<2.1 (12b) Furthermore, as shown in Figure 18, it is preferable to arrange the drive member 122 and the aperture diaphragm 121 so that they overlap in the optical axis direction. In this arrangement, the motor part of the drive member 122 is positioned closer to the object than the aperture diaphragm 121 and inside the outer diameter. The rack 123 is also positioned so that it can move on the outer diameter side of the aperture diaphragm 121. With this arrangement, space for the drive member 122 can be secured, and the lens barrel can be made smaller in the radial direction as well as the optical axis direction.

[0065] Furthermore, as shown in Figure 19, it is preferable to arrange the rack 123 and the aperture diaphragm 121 so that they overlap in the optical axis direction. In this arrangement, the drive member 122 is positioned further inward than in the configuration of Figure 18, and the rack 123 is positioned so that it can move only on the image side of the aperture diaphragm 121. With this arrangement, space for the drive member 122 can be secured, and the lens barrel can be further miniaturized in the radial direction.

[0066] Furthermore, as shown in Figure 20, it is preferable to position the drive member 122 so as to overlap with the notch N of the control board 107. In this arrangement, the control board 107 is made into a C-shape by cutting out a part of a circle, and the drive member 122 is positioned in the space created by the notch. With this arrangement, it is not necessary to secure space in the optical axis direction for both the drive member 122 and the control board 107, so the lens barrel can be made smaller in the optical axis direction.

[0067] Furthermore, as shown in Figure 21, it is preferable to arrange the components constituting the focusing mechanism in the following order from the object side to the image side: aperture diaphragm 121, five-group lens barrel 115 for focus adjustment, control board 107, and filter barrel 117. Since a lens cannot be placed on the image side of the filter barrel 117, the back focus can be reduced by placing the filter barrel 117 on the image side of the focusing mechanism. In addition, by placing the control board 107 on the object side of the filter barrel 117, it is not necessary to secure space in the optical axis direction for both the drive member 122 and the control board 107, so the lens barrel can be made smaller in the optical axis direction.

[0068] In any of the configurations shown in Figures 18 to 21, for example, when the drive member 122 and the aperture diaphragm 121 overlap in a direction perpendicular to the optical axis, it means that when the drive member 122 and the aperture diaphragm 121 are viewed from a direction perpendicular to the optical axis, at least a part of the aperture diaphragm 121 is hidden by the drive member 122. The same applies when multiple members overlap in the direction of the optical axis. Furthermore, the drive member 122 and the aperture diaphragm may or may not be in contact.

[0069] Next, we will describe the detailed configuration of the lens device L0 according to Examples 1 to 6. Note that in each example of the lens device L0, we will omit explanations of overlapping configurations and mainly describe the differences from Example 1.

[0070] [Example 1] Figure 1 shows a cross-sectional view of the lens device L0 of Example 1. The lens device L0 of Example 1 consists of a first lens group L1 and a rear group LR. In the lens device L0 of Example 1, the rear group LR consists of a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group L1 remains stationary relative to the image plane, while the second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5 move toward the object. The focusing group LF is the fourth lens group L4.

[0071] In the lens apparatus L0 of Example 1, the first lens group L1 is composed of two negative lenses. The second lens group L2 is composed of one negative lens, a cemented lens consisting of a positive lens and a negative lens, and another cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side. The third lens group L3 is composed of a cemented lens consisting of two positive and negative lenses, an aperture diaphragm, and one positive lens, arranged in order from the object side. The fourth lens group L4 is composed of a negative lens and a positive lens, arranged in order from the object side. The fifth lens L5 is composed of two cemented lenses consisting of a negative lens and a positive lens. By having three cemented lenses in the optical system, the correction effect of axial chromatic aberration can be further enhanced.

[0072] In the lens apparatus L0 of Example 1, the focusing group LF is the fourth lens group L4, so the 4-group lens barrel 114 is a holding member for the focusing group.

[0073] [Example 2] Figure 3 shows a cross-sectional view of the lens apparatus L0 of Example 2. In the lens apparatus L0 of Example 2, the third lens group L3 is composed of one positive lens, a cemented lens consisting of a negative lens and a positive lens, an aperture diaphragm, and one positive lens, arranged in order from the object side.

[0074] [Example 3] Figure 5 shows a cross-sectional view of the lens device L0 of Example 3. In the lens device L0 of Example 3, the second lens group L2 is composed of a cemented lens consisting of a positive lens and a negative lens, one negative lens, and a cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side. The third lens group L3 is composed of one positive lens, a cemented lens consisting of a positive lens and a negative lens, one positive lens, and an aperture diaphragm, arranged in order from the object side.

[0075] [Example 4] Figure 7 shows a cross-sectional view of the lens device L0 of Example 4. In the lens device L0 of Example 4, the second lens group L2 consists of a positive lens, a negative lens, a negative lens, and a positive lens, arranged in order from the object side. The third lens group L3 consists of a cemented lens consisting of a positive lens and a negative lens, one positive lens, a cemented lens consisting of a negative lens and a positive lens, and an aperture diaphragm, arranged in order from the object side. The fourth lens group L4 consists of a positive lens and a negative lens, arranged in order from the object side. The fifth lens group L5 consists of a negative lens and a positive lens, arranged in order from the object side.

[0076] [Example 5] Figure 9 shows a cross-sectional view of the lens device L0 of Example 5. The lens device L0 of Example 5 consists of a first lens group L1 and a rear group LR. In the lens device L0 of Example 5, the rear group LR consists of a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group L1 is stationary relative to the image plane, while the second lens group L2, third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 move toward the object. The focusing group LF is the fifth lens group L5.

[0077] In the lens apparatus L0 of Example 5, the second lens group L2 consists of a positive lens and a negative lens arranged in order from the object side. The third lens group L3 consists of a cemented lens consisting of a positive lens and a negative lens. The fourth lens group L4 consists of two cemented lenses consisting of a negative lens and a positive lens, arranged in order from the object side, and an aperture diaphragm. The fifth lens group L5 consists of one positive lens. The sixth lens group L6 consists of a negative lens, a positive lens, and a cemented lens consisting of a negative lens and a positive lens, arranged in order from the object side.

[0078] In the lens apparatus L0 of Example 5, the focus group LF is the fifth lens group L5, so the 5-group lens barrel 115 is a holding member for the focus group.

[0079] [Example 6] Figure 11 shows a cross-sectional view of the lens device L0 of Example 6. In the lens device L0 of Example 6, the second lens group L2 consists of a cemented lens made up of a negative lens and a positive lens, and one negative lens. The third lens group L3 consists of a cemented lens made up of a positive lens and a negative lens. The fourth lens group L4 consists of a cemented lens made up of a positive lens, a negative lens, and a positive lens, and an aperture diaphragm. The fifth lens group L5 consists of a positive lens and a negative lens arranged in order from the object side. The sixth lens group L6 consists of a positive lens and a cemented lens made up of a negative lens and a positive lens, arranged in order from the object side. By having three cemented lenses in the optical system, the correction effect of axial chromatic aberration can be further enhanced.

[0080] Next, we will describe the configurations that are preferable to satisfy in the lens device of each embodiment.

[0081] In the lens device L0 of each embodiment, it is preferable that the first lens group L1 has two or more negative lenses in order from the object side. Furthermore, it is preferable that the lens G1 closest to the object has a convex meniscus shape toward the object side, and that the vertex of the object-side surface of the lens G1 closest to the object is located toward the object side of the first lens group barrel 111. This makes it easier to widen the angle of view of the lens device L0.

[0082] In the lens device L0 of each embodiment, it is preferable to make the object-side lens surface and the image-side lens surface of the lens G1 positioned closest to the object a meniscus shape with a convex surface on the object side, as this allows for easier manufacturing of the lens device L0 while satisfying the required optical performance.

[0083] In the lens device L0 of each embodiment, it is preferable that the first lens group L1 is composed of two negative lenses. Furthermore, in the lens device L0 of each embodiment, it is preferable to make all the lenses included in the first lens group L1 spherical lenses, as this makes the manufacturing of the lens device L0 even easier.

[0084] In the lens device L0 of each embodiment, it is preferable to configure the focus group LF with two or fewer lenses and to position it on the image side of the aperture diaphragm SP, as this facilitates miniaturization of the focus group LF and speeds up focusing. Furthermore, in the lens device L0 of each embodiment, a rear focus type is adopted in which the focus group LF is included in the rear group LR. As a result, the overall length of the lens does not change during focusing, making it possible to suppress focusing-induced breathing.

[0085] In the lens apparatus L0 of each embodiment, it is more preferable to configure the rear group LR with three or more lens groups, as this makes it possible to achieve a sufficient magnification ratio.

[0086] The lens device L0 in each embodiment may include distortion correction data for correcting distortion aberration. This allows distortion aberration occurring in the lens optical system to be corrected by the lens device L0. In this case, the lens device L0 includes storage means for storing distortion correction data.

[0087] Furthermore, in the lens device L0 of each embodiment, any arrangement method may be adopted for the arrangement around the drive member 122 shown in Figures 17 to 21, or a combination of multiple arrangement methods may be used.

[0088] Next, numerical examples 1 to 6 corresponding to Examples 1 to 6 are shown below. In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the distance on the optical axis between the m-th surface and the (m + 1)-th surface. Here, m is the surface number counted from the light incident side. Also, nd represents the refractive index with respect to the d-line of the material of each optical member, and νd represents the Abbe number of the material of the optical member. Note that the Abbe number νd of a certain material, when the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines are Nd, NF, and NC, νd = (Nd - 1) / (NF - NC) is represented by

[0089] Also, in each numerical example, d, focal length (mm), F-number, and half angle (°) are all values when the lens device L0 of each example is focused on an infinite object. Note that the back focus is the distance on the optical axis from the most image-side lens surface of the lens device L0 to the paraxial image plane, expressed in terms of the air-equivalent length. The overall length of the lens is the length obtained by adding the back focus to the distance on the optical axis from the most object-side lens surface of the lens device L0 to the most image-side lens surface. Note that the lens group in each numerical example includes not only cases composed of a plurality of lenses but also cases composed of one lens.

[0090] Also, when the optical surface is an aspherical surface, an asterisk (*) is attached to the right side of the surface number. The aspherical shape is expressed as follows when X is the displacement amount from the surface vertex in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, A12 are the aspherical coefficients of each order. 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 + A14 × h 14 ​Note that "e±XX" in each aspherical coefficient is equivalent to "×10± XX This represents ".

[0091] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd 1 48.932 2.00 1.85150 40.8 2 20.284 16.25 3 557.363 1.10 1.80400 46.5 4 28.772 (variable) 5 34.855 0.90 1.85896 22.7 6 17.068 0.10 1.53344 52.7 7* 17.589 4.70 8 50.857 6.99 1.83400 37.2 9 -20.635 1.05 1.49700 81.7 10 22.129 4.34 11 -16.265 0.80 1.49700 81.7 12 21.161 3.64 1.66565 35.6 13 -55.693 (variable) 14 21.234 3.68 1.63980 34.5 15 -27.788 0.70 1.90043 37.4 16 12.518 4.24 1.59270 35.3 17 -87.908 0.91 18 (aperture) ∞ 2.09 19 42.390 4.09 1.49700 81.7 20 -19.741 (variable) 21 -19.756 0.90 2.00100 29.1 22 -46.915 0.10 1.53344 52.7 23* -32.818 0.25 24 49.974 5.10 1.49700 81.7 25 -15.524 (variable) 26 -39.407 0.70 1.81600 46.6 27 24.127 5.47 1.49700 81.7 28 -23.248 (variable) Image plane ∞ Aspherical data Side 7 K = 0.00000e+00 A 4= 4.48181e-07 A 6= 3.99220e-08 A 8=-9.08985e-11 A10= 1.59194e-12 A12=-4.38981e-15 Page 23 K = 0.00000e+00 A 4= 6.12566e-05 A 6= 1.17826e-07 A 8= 2.22470e-09 A10=-3.70114e-11 A12= 2.37590e-13 Various data Zoom ratio 2.00 Wide-angle, Medium, Telephoto Focal length 6.81 9.58 13.60 F-number 2.85 3.23 3.60 Half-angle 58.57 57.09 57.85 Image height 11.15 14.80 21.64 Lens length 127.71 127.71 127.71 BF 30.73 40.08 49.42 d 4 6.34 6.31 2.10 d13 15.72 6.40 1.27 d20 2.33 3.71 3.67 d25 2.47 1.10 1.14 d28 30.73 40.08 49.42 Lens device group data Group starting plane focal length L1 1 -16.55 L2 5 -42.17 L3 14 26.64 L4 21 47.74 L5 26 -101.75

[0092] [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 55.485 2.30 1.85150 40.8 2 19.371 17.05 3 -1103.546 1.30 1.90525 35.0 4 34.645 (variable) 5 37.524 0.90 1.89286 20.4 6 18.491 0.10 1.58946 30.6 7* 18.199 2.37 8 31.026 8.14 1.78880 28.4 9 -20.624 1.10 1.49700 81.7 10 16.423 5.40 11 -14.389 0.80 1.49700 81.7 12 18.091 3.89 1.61340 44.3 13 -39.413 (variable) 14 18.952 4.42 1.53172 48.8 15 -17.614 0.09 16 -17.868 0.70 1.88300 40.8 17 15.902 4.19 1.59270 35.3 18 -41.659 1.44 19 (aperture) ∞ 1.27 20 34.703 4.01 1.49700 81.7 21 -25.217 (variable) 22 -26.388 0.80 1.88300 40.8 23 -78.439 0.10 1.53344 52.7 24* -49.028 0.15 25 31.715 4.97 1.49700 81.7 26 -18.785 (variable) 27 -53.258 0.75 1.88300 40.8 28 19.564 4.78 1.49700 81.7 29 -25.590 (variable) Image plane ∞ Aspherical data Side 7 K = 0.00000e+00 A 4=-9.88827e-06 A 6= 6.80002e-09 A 8=-9.44113e-12 A10= 1.04890e-12 A12=-2.43934e-15 Page 24 K = 0.00000e+00 A 4= 5.68392e-05 A 6= 1.09227e-07 A 8= 3.24013e-10 A10= 1.13582e-12 A12=-2.42531e-14 Various data Zoom ratio 1.97 Wide-angle, Medium, Telephoto Focal length 6.80 9.52 13.41 F-numbers: 2.86, 3.22, 3.61 Half-angle 58.61 57.24 58.16 Image height 11.15 14.80 21.60 Lens length 126.11 126.11 126.11 BF 30.90 39.23 47.55 d 4 4.47 5.13 1.29 d13 14.12 5.13 0.65 d21 4.03 3.69 2.74 d26 1.58 1.92 2.87 d29 30.90 39.23 47.55 Lens device group data Group starting plane focal length L1 1 -14.82 L2 5 -38.96 L3 14 27.05 L4 22 39.68 L5 27 -68.35

[0093] [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 52.863 2.00 1.85150 40.8 2 19.811 16.64 3 268.068 1.30 2.00100 29.1 4 31.150 (variable) 5 159.698 4.99 1.95375 32.3 6 -30.207 1.20 1.49700 81.7 7 16.611 5.20 8 -17.533 0.80 1.49700 81.7 9 18.643 0.28 10 19.966 6.58 1.78880 28.4 11 -12.466 0.80 2.00100 29.1 12 -61.500 (variable) 13* 55.457 0.10 1.58946 30.6 14 97.068 3.52 1.56732 42.8 15 -14.576 0.05 16 -14.461 0.80 2.00100 29.1 17 22.989 3.89 1.59270 35.3 18 -25.500 0.15 19 52.181 4.70 1.63980 34.5 20 -16.612 0.30 21 (aperture) ∞ (variable) 22 -20.107 0.80 1.95375 32.3 23 -48.225 0.10 1.58946 30.6 24* -37.531 0.15 25 48.217 4.74 1.49700 81.7 26 -16.669 (variable) 27 -101.305 0.80 1.88300 40.8 28 18.672 3.74 1.49700 81.7 29 -30.910 (variable) Image plane ∞ Aspherical data Page 13 K = 0.00000e+00 A 4=-5.40095e-05 A 6=-1.58648e-07 A 8=-6.84435e-09 A10= 1.41530e-10 A12=-1.69897e-12 Page 24 K = 0.00000e+00 A 4= 3.89315e-05 A 6= 1.19235e-07 A 8=-4.99023e-10 A10= 1.75021e-11 A12=-1.12723e-13 Various data Zoom ratio 1.97 Wide-angle, Medium, Telephoto Focal length 6.82 9.56 13.42 F-numbers: 2.83, 3.21, 3.60 Half-angle 58.56 57.15 58.14 Image height 11.15 14.80 21.60 Lens length 123.73 123.73 123.73 BF 32.13 40.19 48.25 d 4 7.71 7.34 3.55 d12 13.02 5.32 1.05 d21 5.99 6.19 5.14 d26 1.25 1.05 2.10 d29 32.13 40.19 48.25 Lens device group data Group starting plane focal length L1 1 -14.97 L2 5 -42.81 L3 13 23.42 L4 22 53.48 L5 27 -82.35

[0094] [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 60.163 2.60 1.83481 42.7 2 21.063 12.33 3 109.832 1.50 1.59522 67.7 4 17.672 (variable) 5 150.019 4.20 1.72047 34.7 6 -51.359 1.58 7 -37.627 0.90 1.89190 37.1 8 91.089 2.62 9 -17.827 0.85 1.49700 81.7 10 19.500 0.71 11 24.491 4.63 1.75520 27.5 12 -127.292 (variable) 13* 32.487 0.05 1.58946 30.6 14 24.928 6.44 1.53172 48.8 15 -10.792 0.85 2.00100 29.1 16 -49.566 0.15 17 260.837 3.61 1.59270 35.3 18 -19.964 0.06 19 -83.132 0.90 1.77250 49.6 20 12.974 5.93 1.59270 35.3 21 -21.635 0.87 22 (aperture) ∞ (variable) 23 20.807 4.87 1.49700 81.7 24 -19.178 0.15 25 -22.797 0.80 2.00100 29.1 26 -66.112 (variable) 27 -2019.764 0.80 1.88300 40.8 28 21.543 2.23 29 31.926 3.93 1.49700 81.7 30 -24.775 (variable) Image plane ∞ Aspherical data Page 13 K = 0.00000e+00 A 4= 7.64291e-06 A 6= 4.60507e-07 A 8=-1.46830e-08 A10= 3.93238e-10 A12=-3.23460e-12 Various data Zoom ratio 2.06 Wide-angle, Medium, Telephoto Focal length 7.22 10.80 14.86 F-numbers: 2.88, 3.61, 4.12 Half-angle 56.10 55.97 55.46 Image height 10.75 16.00 21.60 Lens length 128.99 128.99 128.99 BF 32.52 42.88 49.78 d 4 9.19 8.61 5.93 d12 14.96 5.18 0.95 d22 7.59 6.65 3.60 d26 1.17 2.11 5.15 d30 32.52 42.88 49.78 Lens device group data Group starting plane focal length L1 1 -16.14 L2 5 -36.44 L3 13 35.25 L4 23 46.70 L5 27 -822.66

[0095] [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 58.998 2.50 1.76385 48.5 2 15.716 16.74 3 -118.695 1.40 1.59282 68.6 4 37.945 (variable) 5 52.243 3.96 1.66565 35.6 6 -30.668 0.59 7 -22.962 1.00 1.90043 37.4 8 23.854 (variable) 9 23.518 3.91 1.66565 35.6 10 -20.591 1.00 1.49700 81.7 11 22.024 (Variable) 12 18.264 1.00 1.88300 40.8 13 11.917 4.60 1.68430 26.8 14 -39.891 0.15 15 -32.692 1.00 2.05090 26.9 16 17.207 5.02 1.59410 60.5 17 -18.631 0.50 18 (aperture) ∞ (variable) 19 20.545 2.96 1.53775 74.7 20 -202.410 (variable) 21 -60.820 1.28 1.77250 49.6 22* 52.786 0.52 23 80.866 3.72 1.49700 81.7 24 -23.726 0.15 25 -31.425 1.31 1.88300 40.8 26 52.500 3.91 1.49700 81.7 27 -17.095 (variable) Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4= 2.64230e-05 A 6=-4.03358e-09 A 8= 7.40566e-10 A10=-2.79295e-11 A12= 2.33887e-13 Various data Zoom ratio 2.03 Wide-angle, Medium, Telephoto Focal length 7.24 10.93 14.69 F-number 4.10 4.10 4.10 Half-angle 56.05 55.67 55.77 Image height 10.75 16.00 21.60 Lens length 127.38 127.38 127.38 BF 32.32 43.68 51.25 d 4 13.34 9.39 4.19 d 8 5.91 6.34 6.60 d11 11.80 3.96 1.33 d18 3.21 3.73 3.00 d20 3.58 3.06 3.79 d27 32.32 43.68 51.25 Lens device group data Group starting plane focal length L1 1 -14.79 L2 5 -25.40 L3 9 64.83 L4 12 41.50 L5 19 34.85 L6 21 -442.01

[0096] [Numerical Example 6] Unit: mm Surface data Face number rd nd νd 1 58.154 2.50 1.76385 48.5 2 15.775 16.08 3 -425.603 1.40 1.59282 68.6 4 37.744 (variable) 5 248.610 5.62 1.77047 29.7 6 -19.550 1.00 1.95906 17.5 7 -38.557 (variable) 8 -22.637 1.00 1.91354 36.8 9 28.532 3.85 10 28.132 5.18 1.77047 29.7 11 -21.134 1.00 1.43875 94.7 12 22.654 (variable) 13 24.356 6.32 1.68430 26.8 14 -13.488 1.00 2.00100 29.1 15 28.481 4.91 1.51823 58.9 16 -15.181 0.40 17 (aperture) ∞ (variable) 18 22.580 3.05 1.49700 81.7 19 -104.450 (variable) 20 -34.188 1.28 1.76450 49.1 21* 87.503 2.04 22 32.469 4.26 1.49700 81.7 23 -18.234 0.15 24 -176.617 1.31 1.88300 40.8 25 19.236 3.68 1.49700 81.7 26 -61.995 (variable) Image plane ∞ Aspherical data Page 21 K = 0.00000e+00 A 4= 3.50880e-05 A 6= 1.70964e-08 A 8= 3.91104e-09 A10=-9.58126e-11 A12= 7.92141e-13 Various data Zoom ratio 2.06 Wide-angle, Medium, Telephoto Focal length 7.25 11.01 14.97 F-number 4.10 4.10 4.10 Half-angle 56.00 55.46 55.27 Image height 10.75 16.00 21.60 Lens length 131.41 131.41 131.41 BF 32.32 43.52 50.99 d 4 11.62 9.61 3.44 d 7 1.54 1.48 2.68 d12 13.54 4.41 1.90 d17 4.43 4.43 3.35 d19 1.92 1.92 3.00 d26 32.32 43.52 50.99 Lens device group data Group starting plane focal length L1 1 -16.36 L2 5 54.77 L3 8 -23.38 L4 13 42.94 L5 18 37.66 L6 20 -345.10 The various values ​​in each numerical example are summarized in Table 1 below.

[0097] [Table 1]

[0098] [Imaging device] Next, we will describe an imaging device to which the lens device L0 of this embodiment is applied. Figure 13 is a schematic diagram of the imaging device 10 of this embodiment. The imaging device 10 comprises a camera body 13, a lens device 11 which is the same as in any of the embodiments 1 to 6 described above, and a light-receiving element 12 which converts the optical image formed by the lens device 11 into photoelectricity.

[0099] The imaging device 10 of this embodiment has a lens device 11 that is compact and has good optical characteristics, so it can obtain high-quality images.

[0100] Furthermore, an image sensor such as a CCD or CMOS sensor can be used as the light-receiving element 12. In this case, the output image can be made higher quality by electrically correcting various aberrations such as distortion and chromatic aberration of the image acquired by the light-receiving element 12.

[0101] Furthermore, the lens apparatus L0 in each of the above embodiments can be applied not only to the digital still camera shown in Figure 13, but also to various optical instruments such as silver halide film cameras, video cameras, and telescopes.

[0102] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist.

[0103] Furthermore, each embodiment disclosed includes the following configuration.

[0104] (Composition 1) The optical system comprises a first lens group having negative refractive power and a rear lens group having positive refractive power, arranged sequentially from the object side to the image side. In the aforementioned optical system, the distance between adjacent lens groups changes during zooming. The aforementioned rear group includes one or more lens groups and an aperture diaphragm. The focus group, which consists of one or more lens groups from among the lens groups included in the aforementioned rear group, moves in the optical axis direction during focusing. A lens device that satisfies the condition ωw > 85, where ωw (°) is the half-angle of view when in focus at infinity at the wide-angle end, The lens device comprises a holding member for holding the focus group and a driving member for moving the holding member in the optical axis direction. A lens device characterized in that the drive member and the aperture diaphragm overlap in a direction perpendicular to the optical axis.

[0105] (Configuration 2) The lens device according to Configuration 1, characterized in that, when the focal length of the first lens group is fL1 and the focal length of the lens device at the wide-angle end is fw, the following conditional expression is satisfied. -3.0 <fL1 / fw<-1.7 (Composition 3) The aforementioned rear group includes a second lens group having negative refractive power. The lens device according to configuration 1 or 2, characterized in that, when the focal length of the second lens group is fL2 and the focal length of the first lens group is fL1, the following conditional expression is satisfied. -5.0 < |fL2| / fL1 < -1.1 (Composition 4) A lens device according to any one of configurations 1 to 3, characterized in that, when the focal length of the lens G1 positioned closest to the object in the first lens group is fG1 and the focal length of the first lens group is fL1, the following conditional expression is satisfied. 1.4 <fG1 / fL1<3.0 (Composition 5) The lens device according to any one of configurations 1 to 4, characterized in that, when the focal length of lens G1, which is positioned closest to the object in the first lens group, is fG1, and the focal length of lens G2, which is positioned adjacent to lens G1 on the image side, is fG2, the following conditional expression is satisfied. 0.40 <fG1 / fG2<1.60 (Composition 6) The lens device according to any one of configurations 1 to 5, characterized in that, when the focal length of the focus group is fLF and the focal length of the lens device at the wide-angle end is fw, the following conditional expression is satisfied. 3.5 <fLF / fw<15.0 (Composition 7) The lens device according to any one of configurations 1 to 6, characterized in that, when the focal length of the focus group is fLF and the focal length of the first lens group is fL1, the following conditional expression is satisfied. -4.1 <fLF / fL1<-1.8 (Composition 8) A lens device according to any one of configurations 1 to 7, characterized in that, when the focal length of the first lens group is fL1 and the focal length of the rear group at the wide-angle end is fLRw, the following conditional expression is satisfied. -1.30 <fL1 / fLRw<-0.55 (Composition 9) A lens device according to any one of configurations 1 to 8, characterized in that, when the back focus at the wide-angle end is Skw and the focal length of the lens device at the wide-angle end is fw, the following conditional expression is satisfied. 2.0 <Skw / fw<6.0 (Composition 10) The lens device according to any one of configurations 1 to 9, characterized in that, when DSPw is the distance along the optical axis from the aperture diaphragm to the image-side lens surface in the entire system of the lens device at the wide-angle end, and Skw is the back focus at the wide-angle end, the following conditional expression is satisfied. 0.40 <DSPw / Skw<1.00 (Composition 11) The lens apparatus according to any one of configurations 1 to 10, characterized in that, when the refractive index of the material of lens G1, which is positioned closest to the object in the first lens group, with respect to the d line is ndG1, the following conditional expression is satisfied. 1.65 <ndG1<2.20 (Composition 12) The lens G1, which is positioned closest to the object in the first lens group, is a negative lens having a meniscus shape with its convex surface facing the object. The lens device according to any one of configurations 1 to 11, characterized in that, when R1 is the radius of curvature of the object-side lens surface of the lens G1 and R2 is the radius of curvature of the image-side lens surface of the lens G1, the following conditional expression is satisfied. 1.3 < (R1 + R2) / (R1 - R2) < 3.0 (Composition 13) A lens device according to any one of configurations 1 to 12, characterized in that, when the maximum image height at the telephoto end is Yta and the maximum image height at the wide-angle end is Ywa, the following conditional expression is satisfied. 1.5 <Yta / Ywa<3.0 (Composition 14) A lens device according to any one of configurations 1 to 13, characterized by comprising distortion correction data for correcting distortion aberration.

[0106] (Composition 15) The lens device according to any one of configurations 1 to 14, characterized in that the first lens group has at least two negative lenses.

[0107] (Composition 16) The lens device according to any one of configurations 1 to 15, characterized in that the focus group consists of two or fewer lenses.

[0108] (Configuration 17) The lens device according to any one of Configurations 1 to 16, wherein all lens surfaces of the lenses included in the first lens group are spherical surfaces.

[0109] (Configuration 18) The lens device according to any one of Configurations 1 to 17, wherein the rear group is composed of three or more lens groups.

[0110] (Configuration 19) Comprising a one-group lens barrel that holds the first lens group, The lens G1 on the object side in the first lens group has a meniscus shape with a convex surface facing the object side, The lens device according to any one of Configurations 1 to 18, wherein the vertex of the surface on the object side of the lens G1 is located on the object side of the one-group lens barrel.

[0111] (Configuration 20) The lens device according to any one of Configurations 1 to 19, wherein the focus group is arranged on the image side of the aperture stop.

[0112] (Configuration 21) The lens device according to any one of Configurations 1 to 20, wherein the rear group is composed of a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power, which are arranged in order from the object side to the image side.

[0113] (Configuration 22) The lens device according to any one of Configurations 1 to 21, wherein the rear group is composed of a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a negative refractive power, which are arranged in order from the object side to the image side.

[0114] (Configuration 23) The lens device according to any one of configurations 1 to 22, characterized in that the rear group consists of a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

[0115] (Composition 24) The lens device according to any one of configurations 1 to 23, characterized in that the drive member overlaps with the aperture diaphragm in the optical axis direction.

[0116] (Composition 25) The drive member has a transmission member that transmits the driving force to the holding member, The lens device according to any one of configurations 1 to 24, characterized in that the transmission member overlaps with the aperture diaphragm in the optical axis direction.

[0117] (Composition 26) The system comprises a cylindrical member to which the drive member and the aperture diaphragm are fixed, and a control board in contact with the cylindrical member. The lens device according to any one of configurations 1 to 25, characterized in that the drive member overlaps with the control board in a direction perpendicular to the optical axis.

[0118] (Composition 27) The control board has a notch, The lens device according to any one of configurations 1 to 26, characterized in that the drive member overlaps with the notch in a direction perpendicular to the optical axis.

[0119] (Composition 28) The lens device according to any one of configurations 1 to 27, characterized in that the drive member is a stepping motor to which a lead screw is connected.

[0120] (Composition 29) The lens device according to any one of configurations 1 to 28, wherein the drive member and the aperture diaphragm are fixed to a cylindrical member, and the rear group has a filter holding member in contact with the cylindrical member.

[0121] (Composition 30) The control board is in contact with the cylindrical member, The filter holding member includes a drop-in filter. A lens device according to any one of configurations 1 to 29, characterized in that the aperture diaphragm, the holding member, the control board, and the filter holding member are arranged in order from the object side to the image side.

[0122] (Composition 31) A lens device according to any one of configurations 1 to 30, characterized in that when the half-angle of view at infinity focus at the wide-angle end is ωw(°), the condition ωw > 92 is satisfied.

[0123] (Composition 32) An imaging device characterized by having a lens device according to any one of configurations 1 to 32, and an image sensor that receives an image formed by the lens device. [Explanation of Symbols]

[0124] L0 Lens Device L1 First lens group LR rear group LF focus group SP aperture diaphragm 115 5-group lens barrel (holding member) 120 Rear group base tube (tube member) 122 Drive Member 123 Rack (transmission member)

Claims

1. The optical system comprises a first lens group having negative refractive power and a rear lens group having positive refractive power, arranged sequentially from the object side to the image side. In the aforementioned optical system, the distance between adjacent lens groups changes during zooming. The aforementioned rear group includes one or more lens groups and an aperture diaphragm. The focus group, which consists of one or more lens groups from among the lens groups included in the aforementioned rear group, moves in the optical axis direction during focusing. A lens device that satisfies the condition ωw > 85, where ωw (°) is the half-angle of view when in focus at infinity at the wide-angle end, The lens device comprises a holding member for holding the focus group and a driving member for moving the holding member in the optical axis direction. A lens device characterized in that the drive member and the aperture diaphragm overlap in a direction perpendicular to the optical axis.

2. The lens device according to claim 1, characterized in that, when the focal length of the first lens group is fL1 and the focal length of the lens device at the wide-angle end is fw, the following conditional expression is satisfied. -3.0<fL1 / fw<-1.7

3. The aforementioned rear group includes a second lens group having negative refractive power. The lens device according to claim 1, characterized in that, when the focal length of the second lens group is fL2 and the focal length of the first lens group is fL1, the following conditional expression is satisfied. -5.0<|fL2| / fL1<-1.1

4. The lens device according to claim 1, characterized in that, when the focal length of the lens G1 positioned closest to the object in the first lens group is fG1 and the focal length of the first lens group is fL1, the following condition is satisfied. 1.4<fG1 / fL1<3.0

5. The lens device according to claim 1, characterized in that, when the focal length of lens G1, which is positioned closest to the object in the first lens group, is fG1, and the focal length of lens G2, which is positioned adjacent to lens G1 on the image side, is fG2, the following conditional expression is satisfied. 0.40<fG1 / fG2<1.60

6. The lens device according to claim 1, characterized in that, when the focal length of the focus group is fLF and the focal length of the lens device at the wide-angle end is fw, the following condition is satisfied. 3.5<fLF / fw<15.0

7. The lens device according to claim 1, characterized in that, when the focal length of the focus group is fLF and the focal length of the first lens group is fL1, the following condition is satisfied. -4.1<fLF / fL1<-1.8

8. The lens device according to claim 1, characterized in that, when the focal length of the first lens group is fL1 and the focal length of the rear group at the wide-angle end is fLRw, the following conditional expression is satisfied. -1.30<fL1 / fLRw<-0.55

9. The lens device according to claim 1, characterized in that it satisfies the following condition when the back focus at the wide-angle end is Skw and the focal length of the lens device at the wide-angle end is fw. 2.0<Skw / fw<6.0

10. The lens device according to claim 1, characterized in that, when DSPw is the distance along the optical axis from the aperture diaphragm to the image-side lens surface in the entire system of the lens device at the wide-angle end, and Skw is the back focus at the wide-angle end, the following conditional expression is satisfied. 0.40<DSPw / Skw<1.00

11. The lens device according to claim 1, characterized in that, when ndG1 is the refractive index of the material of the lens G1 positioned closest to the object in the first lens group with respect to the d line, the following condition is satisfied. 1.65<ndG1<2.20

12. The lens G1, which is positioned closest to the object in the first lens group, is a negative lens having a meniscus shape with its convex surface facing the object. The lens device according to claim 1, characterized in that, when R1 is the radius of curvature of the object-side lens surface of the lens G1 and R2 is the radius of curvature of the image-side lens surface of the lens G1, the following conditional expression is satisfied. 1.3<(R1+R2) / (R1-R2)<3.0

13. The lens device according to claim 1, characterized in that it satisfies the following condition when Yta is the maximum image height at the telephoto end and Ywa is the maximum image height at the wide-angle end. 1.5<Yta / Ywa<3.0

14. The lens apparatus according to claim 1, characterized by comprising distortion correction data for correcting distortion aberration.

15. The lens device according to claim 1, characterized in that the first lens group has at least two negative lenses.

16. The lens device according to claim 1, characterized in that the focus group consists of two or fewer lenses.

17. The lens device according to claim 1, characterized in that all lens surfaces of the lenses included in the first lens group are spherical.

18. The lens device according to claim 1, characterized in that the aforementioned rear group consists of three or more lens groups.

19. It comprises a single-group lens barrel that holds the first lens group, The lens G1 closest to the object in the first lens group has a meniscus shape with a convex surface facing the object. The lens device according to claim 1, characterized in that the vertex of the object-side surface of the lens G1 is located closer to the object than the first lens group barrel.

20. The lens device according to claim 1, characterized in that the focus group is arranged on the image side of the aperture diaphragm.

21. The lens device according to claim 1, characterized in that the rear group consists of a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power, all arranged in order from the object side to the image side.

22. The lens device according to claim 1, characterized in that the rear group comprises a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

23. The lens device according to claim 1, characterized in that the rear group comprises a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having negative refractive power, all arranged in order from the object side to the image side.

24. The lens device according to claim 1, characterized in that the drive member overlaps with the aperture diaphragm in the optical axis direction.

25. The drive member has a transmission member that transmits the driving force to the holding member, The lens device according to claim 24, characterized in that the transmission member overlaps with the aperture diaphragm in the optical axis direction.

26. The system comprises a cylindrical member to which the drive member and the aperture diaphragm are fixed, and a control board in contact with the cylindrical member. The lens device according to claim 25, characterized in that the drive member overlaps with the control board in a direction perpendicular to the optical axis.

27. The control board has a notch, The lens device according to claim 26, characterized in that the drive member overlaps with the notch in a direction perpendicular to the optical axis.

28. The lens device according to claim 1, characterized in that the drive member is a stepping motor to which a lead screw is connected.

29. The lens device according to any one of claims 1 to 24, wherein the drive member and the aperture diaphragm are fixed to a cylindrical member, and the rear group has a filter holding member that abuts against the cylindrical member.

30. The control board is in contact with the cylindrical member, The filter holding member includes a drop-in filter. The lens device according to claim 29, characterized in that the aperture diaphragm, the holding member, the control board, and the filter holding member are arranged in order from the object side to the image side.

31. The lens device according to claim 1, characterized in that when the half-angle of view at the wide-angle end when in focus at infinity is ωw (°), the condition ωw > 92 is satisfied.

32. An imaging device comprising a lens device as described in claim 30 and an image sensor that receives an image formed by the lens device.

Images