Zoom lens and imaging device having the same

Abstract

To obtain a zoom lens having high optical performance while an entire system is compact and light-weight.SOLUTION: A zoom lens comprises a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group, and a rear group having at least one or more lens groups, which are arranged in order from an object side to an image side, and distances between adjacent lens groups change when zooming. The first lens group has a first lens, and a first negative lens arranged closer to the image side than the first lens, the first negative lens is a lens of which an absolute value of focal distance is smallest among negative lenses constituting the first lens group, curvature radii of lens surfaces on the object side and the image side of the first negative lens, focal distance of the first lens group, and focal distance of the second lens group are appropriately set.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a zoom lens and an imaging device having the same, and is suitable for an imaging device using an image sensor, such as a video camera, an electronic still camera, a broadcast camera, a surveillance camera, etc.

Background Art

[0002] As an imaging optical system, a telephoto zoom lens having a long focal length at the telephoto end is known (Patent Document 1). In such a zoom lens, it is required to have high optical performance while being small and lightweight. Patent Document 1 discloses a zoom lens composed of first to fifth lens groups having positive, negative, positive, negative, and negative refractive powers, arranged in order from the object side to the image side. By setting the first lens group to have a positive refractive power and the fourth and fifth lens groups to have negative refractive powers, a telephoto type configuration is adopted to miniaturize the telephoto zoom lens.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the zoom lens of Patent Document 1, the first lens group is composed of a negative lens, a positive lens, and a positive lens arranged in order from the object side to the image side. Since the negative lens is arranged on the most object side, the axial light beam incident on the positive lenses constituting the first lens group is not sufficiently converged, so the diameter of each lens of the first lens group becomes large, and as a result, it is difficult to achieve sufficient weight reduction of the zoom lens.

[0005] Therefore, an object of the present invention is to provide a zoom lens having high optical performance while the entire system is small and lightweight, and an imaging device having the same. [Means for solving the problem]

[0006] The zoom lens of the present invention comprises a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a rear group having at least one lens group, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, the first lens group comprises a first lens and a first negative lens positioned closer to the image side than the first lens, the first negative lens being the lens with the smallest absolute focal length among the negative lenses constituting the first lens group, and the rear group comprises a fifth lens group with positive refractive power and a sixth lens group with negative refractive power. When R1N1 is the radius of curvature of the object-side surface of the first negative lens, R2N1 is the radius of curvature of the image-side surface of the first negative lens, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and νN1 is the Abbe number with respect to the d-line of the material of the first negative lens, -1.45<(R1N1+R2N1) / (R2N1-R1N1)<2.50 -5.10 <f1 / f2<-1.50 31.0 < νN1 < 60.0 It is characterized by satisfying the following conditional expression. [Effects of the Invention]

[0007] According to the present invention, a zoom lens with high optical performance can be obtained while the entire system is small and lightweight. [Brief explanation of the drawing]

[0008] [Figure 1] Cross-sectional view of the zoom lens at the wide-angle end of Example 1 [Figure 2] Aberration diagrams at the wide-angle and telephoto ends of the zoom lens of Example 1 [Figure 3] Cross-sectional view of the zoom lens at the wide-angle end of Example 2 [Figure 4] Aberration diagrams at the wide-angle and telephoto ends of the zoom lens in Example 2. [Figure 5] Cross-sectional view of the zoom lens at the wide-angle end of Example 3 [Figure 6] Aberration diagrams at the wide-angle and telephoto ends of the zoom lens in Example 3. [Figure 7] Cross-sectional view of the zoom lens at the wide-angle end of Example 4 [Figure 8] Aberration diagrams at the wide-angle and telephoto ends of the zoom lens in Example 4. [Figure 9] Cross-sectional view of the zoom lens at the wide-angle end of Example 5 [Figure 10] Aberration diagrams at the wide-angle and telephoto ends of the zoom lens in Example 5. [Figure 11] Cross-sectional view of the zoom lens at the wide-angle end of Example 6 [Figure 12]Aberration diagrams at the wide-angle end and telephoto end of the zoom lens of Example 6 [Figure 13] Schematic diagram of the main part of the imaging device of the present invention

Mode for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings. The zoom lens in this embodiment consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group, and a rear group having at least one or more lens groups, which are arranged in order from the object side to the image side. Further, the distance between adjacent lens groups changes during zooming.

[0010] FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of Example 1. FIG. 2 is a longitudinal aberration diagram at the wide-angle end and telephoto end (long focal length end) when the zoom lens of Example 1 is focused on an infinite object. Example 1 is a zoom lens with a zoom ratio of 3.69 and an F-number of about 5.15 to 6.50.

[0011] FIG. 3 is a lens cross-sectional view at the wide-angle end of Example 2. FIG. 4 is a longitudinal aberration diagram at the wide-angle end and telephoto end when the zoom lens of Example 2 is focused on an infinite object. Example 2 is a zoom lens with a zoom ratio of 3.76 and an F-number of about 5.83 to 9.00.

[0012] FIG. 5 is a lens cross-sectional view at the wide-angle end of Example 3. FIG. 6 is a longitudinal aberration diagram at the wide-angle end and telephoto end of the zoom lens when focused on an infinite object in Example 3. Example 3 is a zoom lens with a zoom ratio of 3.14 and an F-number of about 6.30 to 9.00.

[0013] FIG. 7 is a lens cross-sectional view at the wide-angle end of Example 4. FIG. 8 is a longitudinal aberration diagram at the wide-angle end and telephoto end of the zoom lens when focused on an infinite object in Example 4. Example 4 is a zoom lens with a zoom ratio of 2.59 and an F-number of about 5.83 to 9.00.

[0014] Figure 9 is a cross-sectional view of the lens at the wide-angle end of Example 5. Figure 10 is a longitudinal aberration diagram of the zoom lens at the wide-angle and telephoto ends when focused on an object at infinity in Example 5. Example 5 is a zoom lens with a zoom ratio of 2.37 and an F-number of approximately 5.77 to 6.50.

[0015] Figure 11 is a cross-sectional view of the lens at the wide-angle end of Example 6. Figure 12 is a longitudinal aberration diagram of the zoom lens at the wide-angle and telephoto ends when focused on an object at infinity in Example 6. Example 6 is a zoom lens with a zoom ratio of approximately 1.95 and an F-number of approximately 4.00.

[0016] The zoom lenses in each embodiment are zoom lenses used in imaging devices such as digital cameras, video cameras, broadcast cameras, surveillance cameras, and silver halide cameras. In the lens cross-section, the left side is the object side (front) and the right side is the image side (rear). The zoom lenses in each embodiment may also be used as projection optics for projection devices (projectors), in which case the left side is the screen side and the right side is the projection target side. In the lens cross-section, L0 is the entire zoom lens system. i indicates the order of the lens groups from the object side, and Li indicates the i-th lens group.

[0017] SP stands for aperture (widest aperture F-number). IP stands for image plane. In digital cameras and video cameras, the image plane IP of a zoom lens corresponds to the image plane of a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor. In silver halide film cameras, the image plane IP of a zoom lens corresponds to the film plane. The arrows show the movement trajectory of the lens group when zooming from the wide-angle end to the telephoto end when focused at infinity. The arrow labeled "focus" shows the direction of movement of the lens group when focusing from an object at infinity to an object at a close distance.

[0018] In the spherical aberration diagram, Fno is the F-number. The solid line d represents the d-line (wavelength 587.6 nm), and the dashed line g represents the g-line (wavelength 435.8 nm). In the astigmatism diagram, the dotted line ΔM represents the meridional image plane at the d-line, and the solid line ΔS represents the sagittal image plane at the d-line. The distortion diagram is shown for the d-line. The chromatic aberration diagram is shown for the g-line. ω is the half-angle of view (degrees).

[0019] The zoom lens in each embodiment consists of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group, and a rear group LR having one or more lens groups, arranged in order from the object side to the image side. In the entire zoom lens system L0 of each embodiment, the spacing between adjacent lens groups changes during zooming. By placing the lens group with positive refractive power closest to the object, it becomes easy to adopt a so-called telephoto type power arrangement, resulting in a configuration advantageous for miniaturizing the entire zoom lens system L0.

[0020] In the zoom lens of each embodiment, the first lens group L1 comprises a first lens and a first negative lens L1N1 positioned on the image side of the first lens. The first negative lens L1N1 is the lens with the smallest absolute focal length among the negative lenses constituting the first lens group L1. When the first lens is a positive lens, the on-axial light beam incident on the first negative lens L1N1 becomes smaller, and the diameter of the first negative lens L1N1 becomes smaller. As a result, the first negative lens L1N1 is made smaller and lighter. When the first lens is a negative lens, the negative refractive power is shared between the first negative lens L1N1 and the first lens, so the bending of light rays passing through the first negative lens L1N1 and the first lens becomes gentler, which is advantageous for correcting various aberrations. Furthermore, because the first negative lens L1N1 is the lens with the smallest absolute focal length among the negative lenses constituting the first lens group L1, it is possible to correct various aberrations while reducing the diameter of the first negative lens L1N1.

[0021] Let R1N1 and R2N1 be the radii of curvature of the object-side and image-side lens surfaces of the first negative lens L1N1, respectively, let f1 be the focal length of the first lens group L1, and f2 be the focal length of the second lens group L2. In this case, the zoom lens of each embodiment is: -1.45<(R1N1+R2N1) / (R2N1-R1N1)<2.50...(1) -5.10 <f1 / f2<-1.50···(2) The following condition is satisfied.

[0022] Next, we will explain the technical meaning of each of the aforementioned conditional expressions.

[0023] Condition (1) defines the shape of the first negative lens L1N1. If the upper limit of condition (1) is exceeded, the curvature of the concave shape of the object-side lens surface becomes too large, making it particularly difficult to correct spherical aberration. If the lower limit of condition (1) is exceeded, the curvature of the concave shape of the image-side lens surface becomes too large, making it particularly difficult to correct coma aberration.

[0024] Condition (2) relates to the focal lengths of the second lens group L2 and the first lens group L1. If the upper limit of condition (2) is exceeded, the focal length of the first lens group L1 becomes shorter, making it particularly difficult to correct axial chromatic aberration occurring in the first lens group L1. If the lower limit of condition (2) is exceeded, the focal length f2 of the second lens group L2 becomes shorter, making it particularly difficult to correct the zoom variation of coma aberration occurring in the second lens group L2.

[0025] Preferably, the conditional expressions (1) and (2) are set as follows. -1.40<(R1N1+R2N1) / (R2N1-R1N1)<1.50...(1a) -5.05 <f1 / f2<-2.00···(2a)

[0026] More preferably, the conditional expressions (1a) and (2a) are set as follows. -1.30<(R1N1+R2N1) / (R2N1-R1N1)<1.00...(1b) -5.00 <f1 / f2<-2.40···(2b)

[0027] Furthermore, it is preferable that the zoom lens of each embodiment satisfies one or more of the following conditions. 3.0<|(1-β4t^2)×βLRt^2|<30.0···(3) -3.00 <fN1 / f1<-0.10···(4) 0.010 <DN1 / Lt<0.400···(5) 0.010 < |f4 / ft| < 0.500 ... (6) 0.20 <Lt / ft<1.20···(7) 0.40 <f1 / fw<4.00···(8) -8.00 < β2t < -0.10 ···(9) 24.0 < νN1 < 60.0 ... (10)

[0028] β4t is the lateral magnification of the fourth lens group L4 when focused on an object at infinity at the telephoto end. βLRt is the lateral magnification of the rear group LR when focused on an object at infinity at the telephoto end. fN1 is the focal length of the first negative lens L1N1. DN1 is the distance along the optical axis from the lens surface closest to the object in the first lens group L1 to the lens surface closest to the object in the first negative lens L1N1. Lt is the distance along the optical axis from the lens surface closest to the object in the first lens group L1 to the image plane at the telephoto end. f4 is the focal length of the fourth lens group L4. ft is the focal length of the entire system at the telephoto end. fw is the focal length of the entire system at the wide-angle end. β2t is the lateral magnification of the second lens group L2 when in focus at infinity at the telephoto end. νN1 is the Abbe number of the first negative lens L1N1 with respect to the d line.

[0029] Next, we will explain the technical meaning of each of the aforementioned conditional expressions.

[0030] Condition (3) specifies the absolute value of the focus sensitivity of the fourth lens group L4. The fourth lens group L4 is a lens group that moves during focusing, and the focus sensitivity is the amount of focus shift when the focusing lens group moves by a unit amount in the optical axis direction. If it exceeds the upper limit of condition (3), the image plane moves significantly for even small movements of the fourth lens group L4 in the optical axis direction, making it difficult to control focus with high precision. If it falls below the lower limit of condition (3), the focus sensitivity becomes too small, the amount of movement of the fourth lens group L4 during focusing becomes large, and the overall zoom lens length L0 becomes longer.

[0031] Condition (4) relates to the focal length of the first negative lens L1N1. If the value exceeds the upper limit of condition (4), the negative refractive power of the first negative lens L1N1 becomes strong, making it particularly difficult to correct spherical aberration and axial chromatic aberration. If the value falls below the lower limit of condition (4), the positive refractive power of the first lens group L1 becomes small, the front principal point is positioned towards the image plane, and as a result the overall zoom lens length L0 becomes longer.

[0032] Condition (5) relates to the arrangement of the first negative lens L1N1. If the upper limit of condition (5) is exceeded, the overall length of the zoom lens system L0 becomes too short, the refractive power of each lens becomes too strong, and it becomes difficult to correct aberrations. If the lower limit of condition (5) is exceeded, the diameter of the first negative lens L1N1 tends to increase, making miniaturization and weight reduction difficult.

[0033] Condition (6) relates to the focal length of the fourth lens group L4. If the upper limit of condition (6) is exceeded, the refractive power of the fourth lens group L4 weakens, and the amount of movement of the fourth lens group L4 during zooming increases in order to obtain the desired zoom ratio. As a result, space is required to accommodate the movement of the fourth lens group L4, and the overall length of the zoom lens system L0 becomes longer. If the lower limit of condition (6) is exceeded, the refractive power of the fourth lens group L4 becomes strong, making it particularly difficult to correct field curvature.

[0034] Condition (7) relates to the overall lens length L0 of the zoom lens system at the telephoto end. If the upper limit of condition (7) is exceeded, the overall lens length L0 of the zoom lens system becomes longer. If the lens length becomes shorter, falling below the lower limit of condition (7), the refractive power of each lens becomes stronger, making it difficult to correct aberrations.

[0035] Condition (8) relates to the focal length of the first lens group L1. If the value exceeds the upper limit of condition (8), the refractive power of the first lens group L1 weakens, the front principal point is positioned towards the image plane, and the overall zoom lens length L0 becomes longer. If the value falls below the lower limit of condition (8), the refractive power of the first lens group L1 strengthens, making it particularly difficult to correct spherical aberration and axial chromatic aberration.

[0036] Condition (9) defines the lateral magnification of the second lens group L2 at the telephoto end. If the upper limit of condition (9) is exceeded, the angle of the on-axis marginal rays incident on the third lens group L3 at the telephoto end becomes large with respect to the optical axis, making it difficult to correct coma aberration, especially at the telephoto end. If the lower limit of condition (9) is exceeded, the angle of the on-axis marginal rays emitted from the second lens group L2 towards the image side at the telephoto end becomes approximately parallel to the optical axis. As a result, in order to miniaturize the entire zoom lens system L0, the refractive power of the lens group on the image side of the second lens group L2 becomes stronger, making it difficult to correct various aberrations.

[0037] Conditional equation (10) specifies the Abbe number for the d line of the first negative lens L1N1. If the value exceeds the upper limit of conditional equation (10), the Abbe number νN1 for the d line of the first negative lens L1N1 becomes too large, resulting in insufficient correction of axial chromatic aberration and, as a result, excessive under-chromatic aberration on the short-wavelength side, which is undesirable. If the value falls below the lower limit of conditional equation (10), the Abbe number νN1 for the d line of the first negative lens L1N1 becomes too small, resulting in excessive correction of axial chromatic aberration and, as a result, excessive over-chromatic aberration on the short-wavelength side, which is also undesirable.

[0038] Preferably, conditional expressions (3) to (10) should be set as follows. 3.1<|(1-β4t^2)×βLRt^2|<25.0···(3a) -2.00 <fN1 / f1<-0.20···(4a) 0.020 <DN1 / Lt<0.300···(5a) 0.030 < |f4 / ft| < 0.400 ···(6a) 0.25 <Lt / ft<1.10···(7a) 0.70 <f1 / fw<2.50···(8a) -6.00 < β2t < -0.40 ···(9a) 31.0 < νN1 < 50.0 ... (10a)

[0039] More preferably, the conditional expressions (3a) to (10a) should be set as follows. 3.3<|(1-β4t^2)×βLRt^2|<20.0···(3b) -1.50 <fN1 / f1<-0.30···(4b) 0.040 <DN1 / Lt<0.250···(5b) 0.040 < |f4 / ft| < 0.350 ···(6b) 0.32 <Lt / ft<0.98···(7b) 0.90 <f1 / fw<2.00···(8b) -5.00 < β2t < -0.80 ···(9b) 34.0 < νN1 < 47.0 ... (10b)

[0040] Furthermore, in order to make the focusing group smaller and lighter, it is preferable to move the fourth lens group L4, which is positioned at a location with a small on-axial light beam, during focusing.

[0041] Furthermore, in order to miniaturize the first negative lens L1N1, it is preferable to make the first lens a positive lens and reduce the on-axial light beam incident on the first negative lens L1N1 from the object side.

[0042] Furthermore, when zooming, it is preferable that the third lens group L3 and at least one lens group of the rear group LR move along the same trajectory. By using the same trajectory, relative eccentricity caused by manufacturing errors between the third lens group L3 and at least one lens group of the rear group LR is suppressed, and as a result, deterioration of optical performance can be suppressed throughout the entire zoom range.

[0043] Furthermore, in order to reduce the weight of the entire zoom lens system L0, it is preferable that the first lens group L1 consists of three lenses.

[0044] In each embodiment, by specifying each element as described above, a zoom lens is obtained that is compact and lightweight as a whole, while possessing high optical performance.

[0045] Next, the lens configuration of each embodiment will be described in detail. The entire zoom lens system L0 of Embodiments 1 to 3 consists of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a rear group LR, arranged in order from the object side to the image side. The rear group LR consists of a lens group LR1 with positive refractive power and a lens group LR2 with negative refractive power, arranged in order from the object side to the image side. By dividing the rear group LR into two groups and moving them along different trajectories during zooming, fluctuations in various aberrations that occur during zooming are suppressed. During zooming, the second lens group L2 is kept immobile relative to the image plane to suppress deterioration of optical performance caused by manufacturing errors.

[0046] Furthermore, in the entire zoom lens system L0 of Examples 1 to 6, the fourth lens group L4 moves during focusing. By moving the fourth lens group L4, which is positioned at a location with a small on-axial light beam, during focusing, it is possible to make the focusing group smaller and lighter.

[0047] Furthermore, in the entire zoom lens system L0 of Examples 1 to 4, the third lens group L3 includes an aperture diaphragm SP. The inclusion of the aperture diaphragm SP in the third lens group L3 improves the symmetry of the optical system, canceling out chromatic aberration and other distortions between the lens on the object side of the aperture diaphragm SP and the lens on the image side of the aperture diaphragm SP, resulting in high optical performance.

[0048] In the zoom lens system L0 of Example 2, the third lens group L3 and the positive refractive power lens group LR1 move along the same trajectory during zooming. As a result, relative eccentricity caused by manufacturing errors between the third lens group L3 and lens group LR1 is suppressed, resulting in high optical performance.

[0049] The zoom lens system L0 of Example 4 consists of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a rear group, arranged sequentially from the object side to the image side. The rear group LR consists of a lens group LR1 with positive refractive power, a lens group LR2 with negative refractive power, and a lens group LR3 with negative refractive power, arranged sequentially from the object side to the image side. By dividing the rear group LR into three lens groups and moving them along different trajectories during zooming, fluctuations in various aberrations that occur during zooming are suppressed. By keeping the second lens group L2 and lens group LR3 immovable relative to the image plane, deterioration of optical performance due to manufacturing errors is suppressed.

[0050] The entire zoom lens system L0 of Examples 5 and 6 consists of a first lens group L1 with positive refractive power, 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 rear group LR, arranged in order from the object side to the image side. The rear group LR consists of a lens group with negative refractive power. By using a five-group configuration, relative eccentricity caused by manufacturing errors in each group is suppressed during zooming, resulting in high optical performance.

[0051] Furthermore, in Examples 1 to 6, it is preferable that all the lenses used are spherical lenses in order to suppress the degradation of optical performance due to manufacturing errors.

[0052] Next, an example of a digital still camera (imaging device) using the optical system (zoom lens) of this embodiment as the imaging optical system will be described with reference to Figure 13. In Figure 13, 10 is the camera body, and 11 is the imaging optical system composed of any of the optical systems described in Examples 1 to 6. 12 is a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor, which is built into the camera body and receives the optical image formed by the imaging optical system 11 and converts it into photoelectric light. The camera body 10 may be a so-called single-lens reflex camera with a quick-turn mirror, or a so-called mirrorless camera without a quick-turn mirror.

[0053] By applying the optical system of this embodiment to an imaging device such as a digital still camera, an imaging device with a compact lens can be obtained.

[0054] The following shows specific numerical examples corresponding to Examples 1 to 6.

[0055] In the surface data for each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axial spacing (distance along the optical axis) between the m-th surface and the (m+1)-th surface. Here, m is the surface number counted from the light incidence side. Furthermore, nd represents the refractive index of each optical element with respect to the d-line, and νd represents the Abbe number of the optical element. Note that the Abbe number νd of a certain material is given by Nd, NF, and NC, respectively, when the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) are Nd, NF, and NC, respectively. It is expressed as νd = (Nd-1) / (NF-NC).

[0056] Furthermore, in each numerical example, d, focal length (mm), F-number, and half-angle of view (°) are all values ​​when the optical system of each example is focused on an object at infinity. "Back focus BF" is the distance along the optical axis from the final lens surface (the lens surface closest to the image) to the paraxial image plane, expressed in terms of air equivalent length. "Total lens length" is the length obtained by adding the back focus to the distance along the optical axis from the frontmost lens surface (the lens surface closest to the object) to the final surface of the zoom lens. "Lens group" includes not only cases where it is composed of multiple lenses, but also cases where it is composed of a single lens.

[0057] Furthermore, Table 1 shows the relationship between each of the aforementioned conditional expressions and each numerical example.

[0058] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd 1 217.722 8.98 1.49700 81.5 2 -539.870 49.14 3 128.109 10.26 1.49700 81.5 4 -255.680 3.43 1.61340 44.3 5 184.292 (variable) 6 -382.436 1.70 1.90043 37.4 7 105.637 3.80 8 -66.783 1.69 1.69680 55.5 9 85.508 4.19 1.80000 29.8 10 -122.182 (variable) 11 42.062 5.58 1.49700 81.5 12 701.208 2.11 13 64.274 3.21 1.48749 70.2 14 196.089 0.15 15 38.408 6.26 1.74077 27.8 16 -164.314 1.70 1.95375 32.3 17 30.538 6.03 18 (aperture) ∞ 1.98 19 1253.439 1.39 2.00100 29.1 20 34.498 5.32 1.51742 52.4 21 -94.055 0.10 22 42.313 3.87 1.76200 40.1 23 -5715.575 (variable) 24 -1620.172 1.94 1.80000 29.8 25 -164.015 1.48 1.65160 58.5 26 58.406 (Variable) 27 172.524 1.49 1.92286 20.9 28 62.317 3.80 29 153.683 3.51 1.72047 34.7 30 -56.463 (variable) 31 -62.685 1.49 1.49700 81.5 32 39.652 2.79 1.73800 32.3 33 82.887 (Variable) Image plane ∞ Various data Zoom ratio 3.69 Wide-angle, Medium, Telephoto Focal length 157.59 299.83 581.33 F-number 5.15 6.00 6.50 Field of view: 7.82 4.13 2.13 Image height 21.64 21.64 21.64 Lens length: 298.01 x 366.01 x 398.03 BF 38.46 65.38 110.60 d 5 11.02 79.02 111.05 d10 46.12 36.63 3.00 d23 19.57 12.37 2.96 d26 22.10 23.28 28.06 d30 23.36 11.95 5.00 d33 38.46 65.38 110.60 Zoom lens group data Group starting plane focal length 1 1 287.41 2 6 -75.69 3 11 63.04 4 24 -93.05 5 27 114.70 6 31 -92.57

[0059] [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 208.809 8.93 1.49700 81.5 2 -664.313 59.70 3 121.285 9.03 1.49700 81.5 4 -275.727 3.15 1.61340 44.3 5 180.051 (variable) 6 -448.212 1.85 1.90043 37.4 7 122.750 2.80 8 -99.147 1.75 1.65160 58.5 9 93.002 4.10 1.80000 29.8 10 -257.065 (variable) 11 324.542 2.59 1.49700 81.5 12 -474.853 0.17 13 43.097 5.44 1.49700 81.5 14 200.512 31.41 15 38.782 5.26 1.67270 32.1 16 -65.741 1.79 1.95375 32.3 17 31.230 4.74 18 (aperture) ∞ 1.61 19 58.971 1.34 2.00100 29.1 20 35.384 3.82 1.48749 70.2 21 -553.969 0.32 22 31.885 3.31 1.62004 36.3 23 172.923 (Variable) 24 91.585 2.41 1.63980 34.5 25 -102.721 1.12 1.87070 40.7 26 37.388 (Variable) 27 297.821 1.62 1.76385 48.5 28 70.624 10.20 29 89.659 1.61 1.92286 20.9 30 42.064 6.26 1.72047 34.7 31 -46.820 (variable) 32 -61.462 1.53 1.49700 81.5 33 36.536 2.39 1.85478 24.8 34 54.437 (Variable) Image plane ∞ Various data Zoom ratio 3.76 Wide-angle, Medium, Telephoto Focal length 206.12 400.00 775.86 F-number 5.83 7.10 9.00 Field of view 5.99 3.10 1.60 Image height 21.64 21.64 21.64 Lens length: 330.40, 393.62, 420.40 BF 37.97 60.16 109.57 d 5 7.82 71.03 97.82 d10 50.12 39.94 2.50 d23 20.02 10.99 2.85 d26 7.67 16.69 24.83 d31 26.56 14.54 2.57 d34 37.97 60.16 109.57 Zoom lens group data Group starting plane focal length 1 1 284.03 2 6 -90.15 3 11 75.47 4 24 -54.88 5 27 69.21 6 32 -71.39

[0060] [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 170.955 2.48 1.56883 56.4 2 121.535 2.32 3 122.798 17.40 1.49700 81.5 4 -521.123 38.15 5 264.986 5.70 1.49700 81.5 6 2053.049 3.52 7 -465.883 3.18 1.91082 35.3 8 1993.620 (Variable) 9 417.339 1.95 1.87070 40.7 10 136.778 4.59 11 -155.184 1.78 1.73400 51.5 12 139.946 4.11 1.85478 24.8 13 20743.346 (variable) 14 194.355 3.42 1.58913 61.1 15 2056.531 0.36 16 49.029 7.59 1.49700 81.5 17 224.084 33.74 18 41.576 6.30 1.59270 35.3 19 -102.320 1.79 1.95375 32.3 20 37.972 5.69 21 (aperture) ∞ 1.92 22 78.911 1.28 1.95375 32.3 23 27.677 5.53 1.48749 70.2 24 4518.430 0.83 25 33.910 4.36 1.68893 31.1 26 351.330 (variable) 27 70.122 3.57 1.84666 23.8 28 -65.992 1.07 2.00100 29.1 29 41.257 (Variable) 30 301.511 1.68 1.76385 48.5 31 36.827 2.23 32 34.813 1.76 1.92286 20.9 33 26.145 5.59 1.59551 39.2 34 -39.106 (variable) 35 -83.052 1.62 1.43875 94.9 36 45.007 18.86 37 -71.024 1.72 1.49700 81.5 38 89.621 2.80 1.85478 24.8 39 6691.960 (variable) Image plane ∞ Various data Zoom ratio 3.14 Wide-angle, Medium, Telephoto Focal length 309.00 550.00 969.91 F-number 6.30 8.00 9.00 Field of view: 4.01 2.25 1.28 Image height 21.64 21.64 21.64 Lens length: 350.21, 418.99, 440.21 BF 38.10 56.62 108.19 d 8 8.00 76.77 98.00 d13 54.99 44.64 2.77 d26 20.08 7.46 2.71 d29 9.68 22.30 27.05 d34 20.48 12.31 2.61 d39 38.10 56.62 108.19 Zoom lens group data Group starting plane focal length 1 1 324.18 2 9 -121.43 3 14 92.54 4 27 -72.58 5 30 81.05 6 35 -52.55

[0061] [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 144.803 10.58 1.49700 81.5 2 -601.382 39.98 3 104.437 7.35 1.49700 81.5 4 731.706 3.52 5 -651.782 4.00 1.61340 44.3 6 108.828 (variable) 7 -19632.712 1.99 1.87070 40.7 8 202.778 2.52 9 -217.537 1.97 1.77250 49.6 10 91.329 3.11 1.85478 24.8 11 361.358 (variable) 12 36.624 6.92 1.49700 81.5 13 458.848 0.50 14 68.891 3.05 1.59522 67.7 15 129.310 2.84 16 39.706 6.89 1.69895 30.1 17 -92.224 1.99 1.91082 35.3 18 31.091 6.26 19 (aperture) ∞ 1.98 20 109.718 1.40 2.00100 29.1 21 22.510 6.31 1.54814 45.8 22 -291.693 1.89 23 29.906 4.69 1.59270 35.3 24 341.177 (variable) 25 5429.529 3.20 1.80000 29.8 26 -54.912 1.50 1.81600 46.6 27 43.639 (Variable) 28 266.700 5.93 1.67300 38.3 29 -28.584 1.47 1.92286 20.9 30 -45.626 (variable) 31 -57.848 2.82 1.85478 24.8 32 -36.634 1.80 1.49700 81.5 33 53.020 (Variable) 34 -42.736 1.79 1.76385 48.5 35 -519.321 0.49 36 77.123 6.83 1.60342 38.0 37 -104.445 (variable) Image plane ∞ Various data Zoom ratio 2.59 Wide-angle, Medium, Telephoto Focal length 300.00 500.00 775.98 F-number 5.83 6.30 9.00 Field of view: 4.12 2.48 1.60 Image height 21.64 21.64 21.64 Lens length: 300.03, 372.57, 400.05 BF 20.03 20.03 20.03 d 6 23.59 96.13 123.60 d11 17.93 18.28 2.96 d24 14.65 7.46 4.31 d27 29.20 34.39 39.21 d30 37.98 19.45 2.98 d33 11.08 31.26 61.38 d37 20.03 20.03 20.03 Zoom lens group data Group starting plane focal length 1 1 359.27 2 7 -105.82 3 12 67.89 4 25 -53.08 5 28 71.42 6 31 -69.31 7 34 -451.68

[0062] [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 210.407 10.15 1.49700 81.5 2 -365.386 3.29 3 244.591 9.81 1.49700 81.5 4 -293.568 2.96 1.83400 37.2 5 1174.271 (variable) 6 852.922 4.46 1.84666 23.8 7 -127.842 1.99 1.59522 67.7 8 82.097 5.33 9 -84.765 1.85 1.75500 52.3 10 3586.628 (variable) 11 204.698 4.97 1.49700 81.5 12 -141.069 0.28 13 126.641 4.87 1.49700 81.5 14 -287.019 0.29 15 79.737 6.22 1.49700 81.5 16 -192.604 2.01 1.90043 37.4 17 163.418 (variable) 18 69.035 2.00 1.84666 23.8 19 31.798 4.87 1.72047 34.7 20 1659.047 (variable) 21 (aperture) ∞ 1.92 22 18.167 3.06 1.58913 61.1 23 15.142 8.01 24 52.055 2.02 1.77250 49.6 25 31.848 2.11 26 -58.595 1.46 1.75500 52.3 27 25.270 2.23 1.84666 23.8 28 64.384 1.93 29 23.724 3.15 1.48749 70.2 30 1797.498 3.91 31 59.680 3.01 2.00100 29.1 32 17.488 5.47 1.61293 37.0 33 -39.917 1.99 34 -37.408 1.99 1.48749 70.2 35 60.162 26.52 36 42.416 4.17 1.48749 70.2 37 105.588 (variable) Image plane ∞ Various data Zoom ratio 2.37 Wide-angle, Medium, Telephoto Focal length 205.00 315.68 485.99 F-number 5.77 6.13 6.50 Field of view: 6.02 3.92 2.55 Image height 21.64 21.64 21.64 Lens length 352.32 352.32 352.32 BF 49.59 49.59 49.59 d 5 29.74 63.49 91.36 d10 70.63 34.68 1.47 d17 62.07 57.31 61.59 d20 1.98 8.94 10.00 d37 49.59 49.59 49.59 Zoom lens group data Group starting plane focal length 1 1 253.56 2 6 -73.95 3 11 92.59 4 18 126.10 5 21 -75.55

[0063] [Numerical Example 6] Unit: mm Surface data Face number rd nd νd 1 1012.750 8.98 1.48749 70.2 2 -494.499 0.80 3 143.865 14.52 1.49700 81.5 4 970.762 27.80 5 127.860 11.39 1.43387 95.1 6 586.201 11.11 7 1488.451 3.04 1.83400 37.2 8 125.386 (variable) 9 85.976 6.60 1.85478 24.8 10 -619.480 1.98 1.67790 55.3 11 63.093 7.03 12 -219.900 1.99 1.95375 32.3 13 345.771 13.82 14 -154.255 1.96 1.77250 49.6 15 2168.606 (variable) 16 1982.719 5.01 1.49700 81.5 17 -87.544 0.50 18 145.338 3.83 1.49700 81.5 19 -1584.777 0.50 20 84.651 7.55 1.49700 81.5 21 -87.563 1.98 1.88300 40.8 22 861.171 (variable) 23 152.675 4.16 1.80518 25.4 24 -167.455 0.50 25 39.487 5.69 1.56732 42.8 26 -1038.960 1.90 1.85478 24.8 27 46.393 (Variable) 28 (aperture) ∞ 1.78 29 74.543 1.82 1.58913 61.1 30 30.785 6.95 31 -2396.299 1.40 1.77250 49.6 32 113.262 2.39 33 -18609.223 1.42 1.85026 32.3 34 92.807 1.85 1.84666 23.8 35 258.057 3.13 36 38.450 2.05 1.54814 45.8 37 53.525 3.59 38 -1139.136 1.45 2.00100 29.1 39 77.278 3.89 1.54072 47.2 40 -73.234 39.94 41 92.104 6.47 1.90043 37.4 42 -95.623 4.11 43 -63.158 1.47 1.48749 70.2 44 95.778 (Variable) Image plane ∞ Various data Zoom ratio 1.95 Wide-angle, Medium, Telephoto Focal length 217.43 280.55 424.43 F-number 4.00 4.00 4.00 Field of view: 5.68, 4.41, 2.92 Image height 21.64 21.64 21.64 Lens length 403.20 403.20 403.20 BF 49.66 49.66 49.66 d 8 35.71 56.86 88.29 d15 56.62 34.96 1.49 d22 30.50 27.88 27.10 d27 4.37 7.49 10.32 d44 49.66 49.66 49.66 Zoom lens group data Group starting plane focal length 1 1 399.85 2 9 -80.45 3 16 95.33 4 23 127.33 5 28 -439.12

[0064] [Table 1]

[0065] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence. [Explanation of symbols]

[0066] L0 Zoom Lens L1 First lens group L1N1 First Negative Lens L2 Second lens group L3 Third lens group L4 4th lens group LR rear group

Claims

1. A zoom lens comprising a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a rear group having at least one lens group, arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming. The first lens group comprises a first lens and a first negative lens positioned on the image side of the first lens. The first negative lens is the lens with the smallest absolute value of focal length among the negative lenses constituting the first lens group, The aforementioned rear group consists of a fifth lens group with positive refractive power and a sixth lens group with negative refractive power. When R1N1 is the radius of curvature of the object-side surface of the first negative lens, R2N1 is the radius of curvature of the image-side surface of the first negative lens, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and νN1 is the Abbe number with respect to the d-line of the material of the first negative lens, -1.45<(R1N1+R2N1) / (R2N1-R1N1)<2.50 -5.10<f1 / f2<-1.50 31.0<νN1<60.0 A zoom lens characterized by satisfying the following conditional equation.

2. The aforementioned fourth lens group moves during focusing. When the lateral magnification at the telephoto end of the fourth lens group is β4t and the lateral magnification at the telephoto end of the rear group is βLRt, 3.0<|(1-β4t^2)×βLRt^2|<30.0 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

3. When the focal length of the first negative lens is fN1, -3.00<fN1 / f1<-0.10 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

4. When DN1 is the distance along the optical axis from the lens surface of the first lens group closest to the object to the lens surface of the first negative lens closest to the object, and Lt is the distance along the optical axis from the lens surface of the first lens group closest to the object to the image plane at the telephoto end, 0.010<DN1 / Lt<0.400 A zoom lens according to any one of claims 1 to 3, characterized in that it satisfies the following conditional expression.

5. When the focal length of the fourth lens group is f4 and the focal length of the entire system at the telephoto end is ft, 0.010<|f4 / ft|<0.500 A zoom lens according to any one of claims 1 to 4, characterized in that it satisfies the following conditional expression.

6. When the focal length of the entire system at the telephoto end is ft, and the distance along the optical axis from the lens surface closest to the object to the image plane of the first lens group at the telephoto end is Lt, 0.20<Lt / ft<1.20 A zoom lens according to any one of claims 1 to 5, characterized in that it satisfies the following conditional expression.

7. When the total focal length of the system at the wide-angle end is fw, 0.40<f1 / fw<4.00 A zoom lens according to any one of claims 1 to 6, characterized in that it satisfies the following conditional expression.

8. When the lateral magnification at the telephoto end of the second lens group is β2t, -8.00<β2t<-0.10 A zoom lens according to any one of claims 1 to 7, characterized in that it satisfies the following conditional expression.

9. The zoom lens according to any one of claims 1 to 8, characterized in that the first lens is a positive lens.

10. The zoom lens according to any one of claims 1 to 9, characterized in that, when zooming, the third lens group and at least one lens group included in the rear group move along the same trajectory.

11. The zoom lens according to any one of claims 1 to 10, characterized in that the first lens group consists of three lenses.

12. A zoom lens consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, a sixth lens group with negative refractive power, and a seventh lens group with negative refractive power, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming. The first lens group comprises a first lens and a first negative lens positioned on the image side of the first lens. The first negative lens is the lens with the smallest absolute value of focal length among the negative lenses constituting the first lens group, When the radius of curvature of the object-side surface of the first negative lens is R1N1, the radius of curvature of the image-side surface of the first negative lens is R2N1, the focal length of the first lens group is f1, and the focal length of the second lens group is f2, -1.45<(R1N1+R2N1) / (R2N1-R1N1)<2.50 -5.10<f1 / f2<-1.50 A zoom lens characterized by satisfying the following conditional equation.

13. A zoom lens consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fifth lens group with negative refractive power, arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming. The first lens group comprises a first lens and a first negative lens positioned on the image side of the first lens. The first negative lens is the lens with the smallest absolute value of focal length among the negative lenses constituting the first lens group, When R1N1 is the radius of curvature of the object-side surface of the first negative lens, R2N1 is the radius of curvature of the image-side surface of the first negative lens, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, ft is the total focal length of the zoom lens system at the telephoto end, and Lt is the distance along the optical axis from the lens surface closest to the object of the first lens group to the image plane at the telephoto end, -1.45<(R1N1+R2N1) / (R2N1-R1N1)<2.50 -5.10<f1 / f2<-1.50 0.20<Lt / ft<1.10 A zoom lens characterized by satisfying the following conditional equation.

14. A zoom lens according to any one of claims 1 to 13, An imaging device characterized by having an image sensor that receives light from the image formed by the zoom lens.

Images