Large aperture ratio ultra-wide angle zoom lens and imaging device equipped with same

Abstract

To provide a large aperture ratio / ultra wide angle zoom lens which includes an ultra wide-angle range with a view angle exceeding 100 degrees in a zoom range, has a small open F-number, and offers superior operability, and to provide an image capturing device having the same.SOLUTION: A wide aperture ratio / ultra wide angel zoom lens provided herein comprises a first lens group G1 having negative refractive power, an intermediate lens group Ga having positive refractive power as a whole, and a final lens group Gb having positive or negative refractive power, arranged in order form the object side, the intermediate lens group Ga comprising an aperture stop S and a focusing lens group LF with negative refractive power configured to move along an optical axis while shifting focus from an object at infinity to a nearby object. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is stationary relative to an image plane and the intermediate lens group Ga moves, decreasing the distance between the first lens group G1 and the intermediate lens group Ga and changing the distance between the intermediate lens group Ga and the final lens group Gb. The zoom lens satisfies given conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a large-aperture ultra-wide-angle zoom lens and an imaging device equipped with the same, and more particularly to a large-aperture ultra-wide-angle zoom lens that has a magnification range that includes an ultra-wide-angle range with a field angle exceeding 100 degrees, a small maximum F-number, a compact overall length, the ability to attach a front filter, and an inner zoom that allows for a slim operating diameter and excellent operability, and an imaging device equipped with the same. [Background technology]

[0002] Conventionally, large-aperture ultra-wide-angle zoom lenses with a small maximum aperture and an angle of view exceeding 100 degrees have been required to provide excellent correction of various aberrations throughout the entire zoom range in order to achieve high imaging performance, to have a small effective diameter for the first lens group so that a front filter can be attached, and to have a compact overall optical system.

[0003] For example, Patent Document 1 discloses a zoom lens having, in order from the object side to the image side, negative, positive, negative, and positive refractive powers, the spacing between each lens group changing during zooming to correct chromatic aberration of magnification at the wide-angle end and axial chromatic aberration at the telephoto end, and having high optical performance throughout the entire zoom range, and in each embodiment, the entire lens system has a retrofocus type refractive power arrangement at the wide-angle end, and the angle of view at the wide-angle end is widened and the first lens group is moved nonlinearly during magnification to correct image plane movement associated with magnification changes, and the zoom lens has a relatively long back focus and an angle of view exceeding 100 degrees.

[0004] Patent Document 2 also discloses a zoom lens with an angle of view exceeding 100 degrees that is intended for mirrorless cameras with a short back focus and is composed of five lens groups with, in order from the object side to the image side, negative, positive, positive, positive or negative, negative refractive power, the spacing between each lens group changes when varying the magnification, and when zooming from the wide-angle end to the telephoto end, the first lens group moves so that it is positioned closer to the image plane at the telephoto end than at the wide-angle end. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-60612 [Patent Document 2] International Publication No. 2018 / 139160 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the zoom lenses disclosed in the above patent documents have the following problems.

[0007] The zoom lens disclosed in Patent Document 1 is a negative refractive power-first zoom lens, and so it does not solve the problems of a long back focus and a long overall optical length. In particular, it is not equipped with a mirror for reflecting an image onto an optical viewfinder, and is therefore unsuitable for application to a mirrorless camera, which has a compact and lightweight camera system as a whole.

[0008] Furthermore, because the first lens group, which has the largest lens diameter, moves when changing magnification from the wide-angle end to the telephoto end, the diameter of the lens barrel becomes large, and the operating diameters of the focus ring, zoom ring, etc. become large, resulting in problems with poor operability.

[0009] The zoom lens disclosed in Patent Document 2 has a structure in which the first lens group, which has the largest lens diameter, moves when changing magnification from the wide-angle end to the telephoto end, which results in a large lens barrel diameter and large operating diameters for the focus ring, zoom ring, etc., leaving issues with operability during shooting.

[0010] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a large aperture ratio ultra-wide-angle zoom lens that has a magnification range that includes an ultra-wide-angle range with an angle of view exceeding 100 degrees, a small maximum F-number, a compact overall length, the ability to attach a front filter, a slim operating diameter achieved by inner zooming, and excellent operability, as well as an imaging device equipped with the same. [Means for solving the problem]

[0011] In order to solve the above problems, a first invention relating to a large aperture ratio ultra-wide-angle zoom lens of the present invention comprises, in order from the object side, a first lens group G1 having a negative refractive power, an intermediate lens group Ga having a positive refractive power as a whole, and a final lens group Gb having a positive or negative refractive power, It consists of three to five lens groups, with the first positive lens group GaP1 closest to the object. Aperture diaphragm S and a second positive lens group GaP2 located closer to the object than the aperture stop S; It includes a focusing lens group LF having negative refractive power that moves along the optical axis when focusing from an object at infinity to an object at a close distance, and when changing magnification from the wide-angle end to the telephoto end, The spacing between adjacent lens groups changes The first lens group G1 is fixed with respect to the image plane, the intermediate lens group Ga moves, the distance between the first lens group G1 and the intermediate lens group Ga decreases, and the distance between the intermediate lens group Ga and the final lens group Gb changes, and the following conditional expression is satisfied: (1) 0.3<|fLF / faw|<3.0 (2) 100.00°<2ωw faw: focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity fLF: focal length of the focusing lens group LF 2ωw: Maximum angle of view of the entire system at the wide-angle end when the object distance is infinite

[0012] In a second aspect of the present invention, the large aperture ratio ultra-wide-angle zoom lens is characterized in that the first lens group G1 and the intermediate lens group Ga satisfy the following conditional expression: (3) 1.0<|faw / f1|<5.0 f1: focal length of the first lens group G1 faw: focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity

[0013] A third aspect of the present invention related to a large aperture ratio ultra wide-angle zoom lens is characterized in that the first lens group G1 comprises, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, and a negative meniscus lens L2 having an aspherical surface and having a convex surface facing the object side, and which satisfies the following conditional expression: (4)1.00<((L2R1+L2R2) / (L2R1-L2R2)) / ((L1R1+L1R2) / (L1R1-L1R2))<3.00 (5) L1nd>1.70 (6) L1νd>40.0 (7) L2nd>1.70 (8) L2νd>35.0 L1R1: radius of curvature of the R1 surface of the negative meniscus lens L1 L1R2: Radius of curvature of the R2 surface of the negative meniscus lens L1 L2R1: radius of curvature of the R1 surface of the negative meniscus lens L2 L2R2: radius of curvature of the R2 surface of the negative meniscus lens L2 L1nd: refractive index of the negative meniscus lens L1 L1νd: Abbe number of the negative meniscus lens L1 L2nd: refractive index of the negative meniscus lens L2 L2νd: Abbe number of the negative meniscus lens L2

[0014] A fourth aspect of the present invention related to a large aperture ratio ultra wide-angle zoom lens is characterized in that the intermediate lens group Ga includes a negative lens group GaN that moves integrally with the aperture diaphragm S, with the aperture diaphragm S being disposed on the object side, during zooming from the wide-angle end to the telephoto end, and that satisfies the following conditional expression: (9) 0.5<|faN / ft|<5.0 faN: focal length of the negative lens group GaN ft: focal length of the entire system at the telephoto end when the object distance is infinity

[0015] A fifth aspect of the present invention relating to a large aperture ratio ultra-wide-angle zoom lens is characterized in that the aperture stop S satisfies the following conditional expression at the telephoto end: (10)0.2 <SPLt / LT<0.9 SPLt: The distance from the aperture stop S to the image plane at the telephoto end LT: distance from the surface of the first lens group G1 closest to the object to the image plane

[0016] The sixth aspect of the present invention relates to a large aperture ratio ultra-wide-angle zoom lens, Wide During zooming from the angular end to the telephoto end, the first positive lens unit GaP1 moves toward the object side, and is characterized in that the following conditional expression is satisfied: (11)1.0 <faP1 / faw<3.0 faP1: focal length of the first positive lens group GaP1 faw: focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity

[0017] The seventh aspect of the present invention, which relates to a large aperture ratio ultra-wide-angle zoom lens, is as follows: Wide During zooming from the corner end to the telephoto end, the second positive lens unit GaP2 moves toward the object side, and is characterized in that the following conditional expression is satisfied: (12)0.3 <faP2 / faw<1.5 faP2: focal length of the second positive lens group GaP2 faw: focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity

[0018] An eighth aspect of the present invention relates to an imaging device, characterized in that it comprises a large aperture ratio super wide-angle zoom lens according to any one of the first to eighth aspects of the present invention. [Effects of the Invention]

[0019] According to the present invention, it is possible to obtain a large aperture ratio ultra-wide-angle zoom lens that has a magnification range that includes an ultra-wide-angle range with an angle of view exceeding 100 degrees, a small maximum F-number, a compact overall length, the ability to attach a front filter, a slim operating diameter achieved by inner zoom, and excellent operability, as well as an imaging device equipped with the same. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to a first embodiment of the present invention when focusing on infinity at the wide-angle end. FIG. [Figure 2] 1 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at the wide-angle end when focused on infinity. FIG. [Figure 3] 1A and 1B are longitudinal aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at an intermediate focal length when focused on infinity. [Figure 4] 1 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at the telephoto end when focused on infinity. FIG. [Figure 5] 4A to 4C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at the wide-angle end when focused on infinity. [Figure 6] 1A and 1B are diagrams illustrating lateral aberration of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at an intermediate focal length when focused on infinity. [Figure 7] 4A to 4C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 1 at the telephoto end when focused on infinity. [Figure 8] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to a second embodiment of the present invention when focusing on infinity at the wide-angle end. [Figure 9] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at the wide-angle end when focused on infinity. [Figure 10] 10A and 10B are longitudinal aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at an intermediate focal length when focused on infinity. [Figure 11] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at the telephoto end when focused on infinity. [Figure 12] 10A and 10B are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at the wide-angle end when focused on infinity. [Figure 13] 10A and 10B are diagrams illustrating lateral aberration of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at an intermediate focal length when focused on infinity. [Figure 14] 10A and 10B are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 2 at the telephoto end when focused on infinity. [Figure 15] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to a third embodiment of the present invention when focusing on infinity at the wide-angle end. [Figure 16] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at the wide-angle end when focused on infinity. [Figure 17] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at an intermediate focal length when focused at infinity. [Figure 18] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at the telephoto end when focused on infinity. [Figure 19] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at the wide-angle end when focused on infinity. [Figure 20] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at an intermediate focal length when focused at infinity. [Figure 21] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 3 at the telephoto end when focused on infinity. [Figure 22] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to a fourth embodiment of the present invention when focusing on infinity at the wide-angle end. [Figure 23] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at the wide-angle end when focused on infinity. [Figure 24] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at an intermediate focal length when focused at infinity. [Figure 25] FIG. 10 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at the telephoto end when focused on infinity. [Figure 26] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at the wide-angle end when focused on infinity. [Figure 27] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at an intermediate focal length when focused at infinity. [Figure 28] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 4 at the telephoto end when focused on infinity. [Figure 29] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to a fifth embodiment of the present invention when focusing on infinity at the wide-angle end. [Figure 30] FIG. 11 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at the wide-angle end when focused on infinity. [Figure 31] 10A and 10B are longitudinal aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at an intermediate focal length when focused at infinity. [Figure 32] FIG. 11 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at the telephoto end when focused on infinity. [Figure 33] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at the wide-angle end when focused on infinity. [Figure 34] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at an intermediate focal length when focused at infinity. [Figure 35] 10A to 10C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 5 at the telephoto end when focused on infinity. [Figure 36] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to Example 6 of the present invention when focusing on infinity at the wide-angle end. [Figure 37] FIG. 13 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at the wide-angle end when focused on infinity. [Figure 38] 13A to 13C are longitudinal aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at an intermediate focal length when focused on infinity. [Figure 39] FIG. 13 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at the telephoto end when focused on infinity. [Figure 40] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at the wide-angle end when focused on infinity. [Figure 41] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at an intermediate focal length when focused at infinity. [Figure 42] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 6 at the telephoto end when focused on infinity. [Figure 43] FIG. 10 is a diagram illustrating the lens configuration of a large aperture ratio ultra-wide-angle zoom lens according to Example 7 of the present invention when focusing on infinity at the wide-angle end. [Figure 44] FIG. 13 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at the wide-angle end when focused on infinity. [Figure 45] FIG. 13 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at an intermediate focal length when focused at infinity. [Figure 46] FIG. 13 is a longitudinal aberration diagram of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at the telephoto end when focused on infinity. [Figure 47] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at the wide-angle end when focused on infinity. [Figure 48] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at an intermediate focal length when focused at infinity. [Figure 49] 13A to 13C are lateral aberration diagrams of the large aperture ratio ultra-wide-angle zoom lens of Example 7 at the telephoto end when focused on infinity. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of a large aperture ratio super wide-angle zoom lens according to the present invention will be described in detail with reference to the accompanying drawings.

[0022] 1, 8, 15, 22, 29, 36, and 43 are lens construction diagrams of the large aperture ratio ultra-wide-angle zoom lens of the present invention. As shown in each lens construction diagram, the large aperture ratio ultra-wide-angle zoom lens of the present invention is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power, and a final lens group Gb with positive or negative refractive power. The intermediate lens group Ga is composed of three or more lens groups.

[0023] In the large aperture ratio ultra wide-angle zoom lens of the present invention, when changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the distance between the first lens group G1 and the intermediate lens group Ga decreases, and the distance between the intermediate lens group Ga and the final lens group Gb changes.

[0024] The intermediate lens group Ga includes an aperture stop S, a negative lens group GaN that moves integrally with the aperture stop S when changing magnification from the wide-angle end to the telephoto end, a positive lens group GaP1 closest to the object, and a positive lens group GaP2 closer to the object than the aperture stop S.

[0025] The intermediate lens group Ga also includes a focusing lens group LF having negative refractive power that moves on the optical axis when focusing from an object at infinity to an object at a close distance.

[0026] Focusing can be performed by any negative lens group in the intermediate lens group Ga, and any negative lens group may be added separately as a focus lens group.

[0027] In the large aperture ratio ultra-wide-angle zoom lens of the present invention, the main zoom effect is achieved by shortening the distance between the first lens group G1, which has negative refractive power, and the middle lens group Ga, which has positive refractive power, when zooming from the wide-angle end to the telephoto end.

[0028] At the wide-angle end, the distance between the first lens group G1 and the intermediate lens group Ga is increased to create a strong reverse telephoto structure, and at the telephoto end, the distance between the lens groups on the object side of the aperture diaphragm S provided in the first lens group G1 and the intermediate lens group Ga is decreased to reduce the positive refractive power on the object side of the aperture diaphragm S, thereby increasing the focal length of the entire system.

[0029] At the wide-angle end, the first lens group G1, which has negative refractive power, and the intermediate lens group Ga, which has positive refractive power, are spaced apart so as to obtain sufficient negative refractive power, and the final lens group Gb is positioned closer to the image side than the combined system of the first lens group G1 and the intermediate lens group Ga.

[0030] In an ultra-wide-angle zoom lens for a mirrorless camera with a short back focal length, if the final lens group Gb is entirely made up of positive lenses, it is desirable to configure the final lens group Gb with a GbP subsystem having positive refractive power on the object side and a GbN subsystem having negative refractive power on the image side, thereby creating a symmetrical optical system that makes it easy to correct aberrations at the wide-angle end.

[0031] On the other hand, at the telephoto end, the first lens group G1 with negative refractive power and the intermediate lens group Ga with positive refractive power are positioned close to each other so that the positive refractive power is smaller on the object side than the aperture stop S, and the lens spacing between the positive lens group GaP2 and the negative lens group GaN that moves integrally with the aperture stop S is widened, thereby preventing an increase in the aperture diameter at the telephoto end.

[0032] Furthermore, the large aperture ratio super wide-angle zoom lens of the present invention satisfies the following conditional expressions (1) and (2). (1) 0.3<|fLF / faw|<3.0 (2) 100.00°<2ωw faw: Focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity fLF: focal length of the focusing lens group LF 2ωw: Maximum angle of view of the entire system at the wide-angle end when the object distance is infinite

[0033] Conditional formula (1) represents the ratio of the focal lengths of the focusing lens unit LF and the intermediate lens unit Ga at the wide-angle end.

[0034] If the lower limit of conditional expression (1) is exceeded and the negative refractive power of the focusing lens unit LF becomes weaker relative to the refractive power of the intermediate lens unit Ga, the amount of movement of the focus lens increases, making it difficult to ensure sufficient space for movement.

[0035] If the upper limit of conditional expression (1) is exceeded and the negative refractive power of the focusing lens unit LF becomes stronger than the refractive power of the intermediate lens unit Ga, aberration fluctuations during focusing cannot be suppressed.

[0036] By limiting the lower limit of the above-mentioned conditional expression (1) to 0.6 and the upper limit to 2.5, the above-mentioned effect can be more reliably achieved.

[0037] Conditional expression (2) defines the maximum angle of view at the wide-angle end.

[0038] If the lower limit of conditional expression (2) is exceeded and the maximum angle of view at the wide-angle end becomes small, the angle of view as an ultra-wide angle of a large aperture ratio ultra-wide-angle zoom lens becomes insufficient, which is undesirable.

[0039] By setting the lower limit of the above-mentioned conditional expression (2) to 105.00°, the above-mentioned effect can be achieved more reliably.

[0040] In a large aperture ratio ultra-wide-angle zoom lens with an angle of view exceeding 100 degrees at the wide-angle end, achieving both a wide angle of view and a large aperture ratio poses the problem of increasing the effective diameter of the first lens group G1. Furthermore, when changing magnification from the wide-angle end to the telephoto end, moving the heavy first lens group G1 with its large effective diameter increases the diameter of the lens barrel that holds the first lens group G1, which results in a problem of increasing the operating diameter of the zoom ring, focus ring, etc.

[0041] The present invention is a large aperture ratio ultra-wide-angle zoom lens with an angle of view exceeding 100 degrees at the wide-angle end, and by fixing the first lens group G1 when changing magnification from the wide-angle end to the telephoto end, it is possible to reduce the overall length of the lens barrel and the operating diameter.

[0042] Furthermore, the first lens group G1, which is fixed relative to the image plane during zooming, and the intermediate lens group Ga having positive refractive power satisfy the following conditional expression (3) at the wide-angle end. (3) 1.0<|faw / f1|<5.0 f1: focal length of the first lens group G1 faw: Focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinity

[0043] Conditional expression (3) defines the ratio of the focal lengths of the first lens group G1 and the intermediate lens group Ga at the wide-angle end.

[0044] If the lower limit of conditional expression (3) is exceeded and the negative refractive power of the first lens group G1 becomes small, it becomes difficult to ensure a sufficient back focal length. Furthermore, to achieve a sufficiently wide angle of view, it is necessary to increase the distance between the first lens group G1 and the intermediate lens group Ga. This then requires an increase in the lens diameter of the first lens group G1, which creates the problem of increasing the diameter of the front filter to properly capture peripheral light rays in a wide-angle lens with a large angle of view. Furthermore, while shortening the focal length of the intermediate lens group Ga at the wide-angle end contributes to compactness, it becomes difficult to ensure a sufficient back focal length, making it difficult to correct spherical aberration that occurs in the intermediate lens group Ga.

[0045] If the upper limit of conditional expression (3) is exceeded and the negative refractive power of the first lens group G1 becomes large, not only will the overall lens length increase, but the effective diameter of the intermediate lens group Ga and the aperture diameter will also increase, making it difficult to reduce the operating diameter. Furthermore, if the focal length of the intermediate lens group Ga at the wide-angle end increases, the overall lens length will also increase.

[0046] For these reasons, by observing the conditional range of conditional expression (3), it is possible to realize a large aperture ratio ultra-wide-angle zoom lens that strikes a good balance between compact size and high performance.

[0047] By limiting the lower limit of the above-mentioned conditional expression (3) to 1.5 and the upper limit to 3.5, the above-mentioned effect can be more reliably achieved.

[0048] In addition, in the large aperture ratio ultra wide-angle zoom lens of the present invention, the first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, and a negative meniscus lens L2 having an aspherical surface and having a convex surface facing the object side, and satisfies the following conditional expressions (4) to (8): (4)1.00<((L2R1+L2R2) / (L2R1-L2R2)) / ((L1R1+L1R2) / (L1R1-L1R2))<3.00 (5) L1nd>1.70 (6) L1νd>40.0 (7) L2nd>1.70 (8) L2νd>35.0 L1R1: Radius of curvature of the R1 surface of the negative meniscus lens L1 L1R2: Radius of curvature on the R2 surface of the negative meniscus lens L1 L2R1: Radius of curvature on the R1 surface of the negative meniscus lens L2 L2R2: Radius of curvature of the R2 surface of the negative meniscus lens L2 L1nd: Refractive index of the L1 lens L1νd: Abbe number of the L1 lens L2nd: Refractive index of the L2 lens L2νd: Abbe number of the L2 lens

[0049] In a large-aperture, ultra-wide-angle zoom lens, the first lens group G1, which has negative refractive power, includes negative meniscus lens L1 and negative meniscus lens L2, arranged with appropriate power and in a well-balanced manner, allowing for appropriate correction of various aberrations, such as astigmatism, coma, and distortion, at the wide-angle end, which provides a large angle of view. Furthermore, by making these lenses aspherical, the light beam diameter of the first lens group G1 can be reduced, thereby enabling a smaller front filter diameter and a wider angle of view. In particular, it is desirable to make the negative meniscus lens L2, which has a relatively small lens diameter, aspherical, because increasing its refractive power makes it difficult to correct astigmatism, coma, distortion, and other aberrations. Furthermore, by simultaneously making the negative meniscus lens L1 aspherical, it is possible to increase the refractive power of the negative meniscus lens L1 by reducing the central curvature of the R1 surface of the negative meniscus lens L1 while providing an appropriate slope for the peripheral curvature at the wide angle of view.

[0050] Conditional expression (4) defines the ratio of the shapes, or so-called shape factors, of the negative meniscus lens L1 and the negative meniscus lens L2 in the first lens group G1.

[0051] To achieve a wide angle of view at the wide-angle end of a large-aperture ratio ultra-wide-angle zoom lens, it is necessary to increase the refractive power of the negative meniscus lens L1 and the negative meniscus lens L2 in the first lens group G1. Increasing the shape factor is an effective way to increase the refractive power of the negative meniscus lens L1 and the negative meniscus lens L2, and using aspherical lenses is an effective way to ensure an appropriate surface inclination angle for peripheral light flux. However, increasing the negative refractive power of a negative meniscus aspherical lens increases the thickness deviation ratio, which can lead to problems with the fabrication of the aspherical lens. By satisfying conditional expression (4) and appropriately setting the shape factor ratio of the negative meniscus lens L1 and the negative meniscus lens L2, it is possible to achieve a good balance between high performance and a wide angle of view at the wide-angle end, as well as a reduction in the front filter diameter, ease of fabrication of the negative meniscus aspherical lens, and improvement of inter-surface ghosting caused by reflections from the surfaces of the negative meniscus lens L1 and the negative meniscus lens L2.

[0052] If the upper limit of conditional expression (4) is exceeded and the ratio between the shape factors of the negative meniscus lens L1 and the negative meniscus lens L2 becomes large, the refractive power of the negative meniscus lens L2, which has an aspherical surface, becomes strong, making lens processing difficult. Also, if the refractive power of the negative meniscus lens L1 becomes weak, it becomes difficult to achieve a small front filter diameter.

[0053] If the lower limit of conditional expression (4) is exceeded and the ratio of the shape factors of the negative meniscus lens L1 and the negative meniscus lens L2 becomes small, the refractive power of the negative meniscus lens L1 becomes strong, and if the peripheral curvature of the R2 surface of the negative meniscus lens L1 becomes large, there is a concern that the effects of ghosts caused by reflections on the periphery of the R2 surface of the negative meniscus lens L1 will worsen.

[0054] By limiting the lower limit of the above-mentioned conditional expression (4) to 1.01 and the upper limit to 2.10, the above-mentioned effect can be more reliably achieved.

[0055] Furthermore, in an ultra-wide-angle lens having a large maximum angle of view, in order to increase the refractive power of the negative meniscus lens L1 and negative meniscus lens L2 in the first lens group G1, which has negative refractive power, it is important to use a glass material with a high refractive index and to select a glass material with an appropriate Abbe number in order to correct the chromatic aberration of magnification that occurs significantly at the peripheral angles of view of an ultra-wide-angle lens, and conditional expressions are set to stipulate these.

[0056] Condition (5) defines the refractive index of the negative meniscus lens L1. By using a glass material with a high refractive index, sufficient refractive power can be obtained without increasing the curvature of the R2 surface of the negative meniscus lens L1.

[0057] If the lower limit of conditional expression (5) is exceeded and the refractive index of the negative meniscus lens L1 becomes small, the negative meniscus lens L1 will not have sufficient refractive power, making it difficult to achieve both a wide angle of view and high performance.

[0058] By setting the lower limit of the above-mentioned conditional expression (5) to 1.73, the above-mentioned effect can be achieved more reliably.

[0059] Conditional formula (6) defines the Abbe number of the negative meniscus lens L1. By using a glass material with lower dispersion, it becomes possible to reduce lateral chromatic aberration, which occurs significantly at the peripheral angles of view of an ultra-wide-angle lens.

[0060] If the lower limit of conditional expression (6) is exceeded and the dispersion of the negative meniscus lens L1 becomes large, the chromatic aberration of magnification occurring in the negative meniscus lens L1 becomes unacceptable.

[0061] By setting the lower limit of the above-mentioned conditional expression (6) to 48.0, the above-mentioned effect can be achieved more reliably.

[0062] Condition (7) defines the refractive index of the negative meniscus lens L2. By using a glass material with a high refractive index, sufficient refractive power can be obtained without increasing the curvature of the R2 surface of the negative meniscus lens L2.

[0063] If the lower limit of conditional expression (7) is exceeded and the refractive index of the negative meniscus lens L2 becomes small, the negative meniscus lens L2 will not have sufficient refractive power, making it difficult to achieve both a wide angle of view and high performance.

[0064] By setting the lower limit of the above-mentioned conditional expression (7) to 1.75, the above-mentioned effect can be achieved more reliably.

[0065] Conditional formula (8) defines the Abbe number of the negative meniscus lens L2. By using a glass material with lower dispersion, it becomes possible to reduce lateral chromatic aberration, which occurs significantly at the peripheral angles of view of an ultra-wide-angle lens.

[0066] If the lower limit of conditional expression (8) is exceeded and the dispersion of the L2 lens becomes large, the chromatic aberration of magnification occurring in the negative meniscus lens L2 becomes unacceptable.

[0067] By setting the lower limit of the above-mentioned conditional expression (8) to 40.0, the above-mentioned effect can be ensured more reliably.

[0068] Furthermore, the intermediate lens group Ga has a negative lens group GaN that moves integrally with the aperture stop S disposed on the object side during zooming from the wide-angle end to the telephoto end, and satisfies conditional expression (9). (9) 0.5<|faN / ft|<5.0 faN: focal length of negative lens group GaN ft: focal length of the entire system at the telephoto end when the object distance is infinity

[0069] Conditional formula (9) expresses the ratio of the negative lens group GaN in the intermediate lens group Ga to the focal length of the entire system at the telephoto end when the object distance is infinite. At the telephoto end, by appropriately setting the focal length of the negative component immediately after the aperture stop S with respect to the positive component on the object side of the aperture stop S, it is possible to achieve both compactness and high performance at the telephoto end.

[0070] If the refractive power of the negative lens group GaN becomes too strong beyond the lower limit of conditional expression (9), the telephoto effect becomes stronger, which is advantageous for size reduction at the telephoto end. However, it becomes difficult to correct axial chromatic aberration, lateral chromatic aberration, and the like at the telephoto end, making it difficult to maintain performance.

[0071] If the refractive power of the negative lens group GaN becomes weaker beyond the upper limit of conditional expression (9), the telephoto effect becomes insufficient, resulting in an increase in the overall lens length.

[0072] By limiting the lower limit of the above-mentioned conditional expression (9) to 0.8 and the upper limit to 2.5, the above-mentioned effect can be more reliably achieved.

[0073] Furthermore, the aperture stop S satisfies conditional expression (10) at the telephoto end. (10)0.2 <SPLt / LT<0.9 SPLt: Distance from aperture stop S to the image plane at the telephoto end LT: Distance from the surface of the first lens group G1 closest to the object to the image plane

[0074] Conditional expression (10) expresses the ratio of the distance from the aperture stop S to the image plane at the telephoto end to the distance from the surface of the first lens group G1 closest to the object to the image plane.

[0075] By appropriately setting the distance from the aperture diaphragm S to the image plane at the telephoto end, in a zoom lens with negative refractive power leading and a fixed F-number, movement of the aperture diaphragm S due to zooming is small, and it is easy to ensure space before and after the diaphragm, facilitating the placement of the aperture diaphragm S, and it becomes possible to place the aperture diaphragm S on the object side of the negative lens group, which allows the diaphragm diameter to be set small. Furthermore, by setting the distance from the aperture diaphragm S to the image plane to be small at the telephoto end, it becomes possible to set the diaphragm diameter at the telephoto end to be small, allowing the operating diameter of the zoom ring, focus ring, etc. to be small.

[0076] If the distance from the aperture stop S to the image plane at the telephoto end becomes smaller beyond the lower limit of conditional expression (10), this is advantageous for reducing the aperture diameter at the telephoto end, but there is a risk of one-sided aperture stop occurring. Also, the zoom movement amount of the positive lens group that is located behind the negative lens group GaN and moves toward the object side during zooming becomes smaller, reducing the magnification effect.

[0077] If the distance from the aperture stop S to the image plane at the telephoto end exceeds the upper limit of conditional expression (10), the aperture stop S will be farther away from the image plane, making it difficult to reduce the aperture diameter.

[0078] By limiting the lower limit of the above-mentioned conditional expression (10) to 0.4 and the upper limit to 0.7, the above-mentioned effect can be more reliably achieved.

[0079] The intermediate lens group Ga has the first positive lens group GaP1 closest to the object side, and moves toward the object side when varying the magnification from the wide-angle end to the telephoto end, thereby satisfying conditional expression (11). (11)1.0 <faP1 / faw<3.0 faP1: focal length of the first positive lens group GaP1 faw: Focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinite

[0080] Conditional formula (11) expresses the ratio between the focal length of the first positive lens group GaP1 in the intermediate lens group Ga and the focal length at the wide-angle end of the intermediate lens group Ga. By satisfying this conditional range, the light beam diverging from the first lens group G1, which has negative refractive power, is appropriately suppressed, and spherical aberration and astigmatism occurring in the first lens group G1 are appropriately suppressed.

[0081] If the refractive power of the first positive lens group GaP1 becomes too strong beyond the lower limit of conditional expression (11), it is possible to set the effective diameter of the lenses in the subsequent groups to be small, but it becomes difficult to suppress the spherical aberration that occurs in the first positive lens group GaP1.

[0082] If the refractive power of the first positive lens unit GaP1 becomes too small beyond the upper limit of conditional expression (11), the effective diameter of the lenses in the subsequent lens units including the second positive lens unit GaP2 becomes large, which is unfavorable for reducing the diameter of the lens barrel.

[0083] By limiting the lower limit of the above-mentioned conditional expression (11) to 1.1 and the upper limit to 2.1, the above-mentioned effect can be more reliably achieved.

[0084] The intermediate lens group Ga has a second positive lens group GaP2 located closer to the object side than the aperture stop S, moves toward the object side when varying magnification from the wide-angle end to the telephoto end, and satisfies the following conditional expression (12). (12)0.3 <faP2 / faw<1.5 faP2: focal length of the second positive lens group GaP2 faw: Focal length at the wide-angle end of the intermediate lens group Ga when the object distance is infinite

[0085] Conditional expression (12) expresses the ratio between the focal length of the second positive lens group GaP2 in the intermediate lens group Ga and the focal length at the wide-angle end of the intermediate lens group Ga. Satisfying this conditional range makes it possible to appropriately define the focal length of the second positive lens group GaP2, which has a large amount of movement during zooming and is used to change the magnification.

[0086] If the focal length of the second positive lens unit GaP2 becomes short beyond the lower limit of conditional expression (12), it becomes impossible to suppress the spherical aberration occurring in the second positive lens unit GaP2.

[0087] If the focal length of the second positive lens unit GaP2 becomes large beyond the upper limit of conditional expression (12), a problem occurs in that the magnification effect of the second positive lens unit GaP2 cannot be sufficiently obtained during zooming from the wide-angle end to the telephoto end.

[0088] By limiting the lower limit of the above-mentioned conditional expression (12) to 0.5 and the upper limit to 1.0, the above-mentioned effect can be more reliably achieved.

[0089] Next, the lens configuration of the large aperture ratio super wide-angle zoom lens of this embodiment will be described. In the following description, the lens configuration will be described in order from the object side to the image side. [Example]

[0090] FIG. 1 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to a first embodiment of the present invention.

[0091] The large aperture ratio ultra wide-angle zoom lens of Example 1 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, an aperture stop S, and a fourth lens group G4 with negative refractive power, and the final lens group Gb is composed of a fifth lens group G5 with positive refractive power.

[0092] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side together with the aperture stop S, and the fifth lens group G5 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 changes.

[0093] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the third lens group G3 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fourth lens group G4 with negative refractive power correspond to the negative lens group GaN.

[0094] The aperture stop S is located on the object side of the fourth lens group G4. The fourth lens group G4 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to a close object, the focusing lens group LF moves along the optical axis toward the image plane independently of the aperture stop S.

[0095] The first lens group G1 is composed of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces the object side, a biconcave lens L3, and a biconvex lens L4.

[0096] The second lens group G2 is composed of a biconvex lens L5 with an aspherical surface R1, and a cemented lens made up of a biconvex lens L6 and a biconcave lens L7.

[0097] The third lens group G3 is composed of a cemented lens consisting of a negative meniscus lens L8 with its convex surface facing the object side and a biconvex lens L9, and a biconvex lens L10 with aspherical surfaces R1 and R2.

[0098] The fourth lens group G4 is composed of a plano-concave lens L11 with its flat surface facing the object side.

[0099] The fifth lens group G5 is composed of a biconvex lens L12, a cemented lens consisting of a biconvex lens L13 and a biconcave lens L14, and a biconvex lens L15 whose surfaces R1 and R2 are aspherical. [Example]

[0100] FIG. 8 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to a second embodiment of the present invention.

[0101] The large aperture ratio ultra wide-angle zoom lens of Example 2 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, an aperture stop S, and a fourth lens group G4 with negative refractive power, and the final lens group Gb is composed of a fifth lens group G5 with positive refractive power.

[0102] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side together with the aperture stop S, and the fifth lens group G5 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 changes.

[0103] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the third lens group G3 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fourth lens group G4 with negative refractive power correspond to the negative lens group GaN.

[0104] The aperture stop S is located on the object side of the fourth lens group G4. The fourth lens group G4 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to a close object, the focusing lens group LF moves along the optical axis toward the image plane independently of the aperture stop S.

[0105] The first lens group G1 is composed of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces the object side, a biconcave lens L3, and a biconvex lens L4.

[0106] The second lens group G2 is composed of a positive meniscus lens L5 whose R1 and R2 surfaces are aspherical and whose convex surface faces the object side, and a cemented lens made up of a biconvex lens L6 and a biconcave lens L7.

[0107] The third lens group G3 is composed of a cemented lens consisting of a negative meniscus lens L8 with its convex surface facing the object side and a biconvex lens L9, and a biconvex lens L10 with aspherical surfaces R1 and R2.

[0108] The fourth lens group G4 is composed of a biconcave lens L11.

[0109] The fifth lens group G5 is composed of a biconvex lens L12, a cemented lens consisting of a biconvex lens L13 and a biconcave lens L14, and a biconvex lens L15 whose surfaces R1 and R2 are aspherical. [Example]

[0110] FIG. 15 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to a third embodiment of the present invention.

[0111] The large aperture ratio ultra wide-angle zoom lens of Example 3 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, an aperture stop S, and a fourth lens group G4 with negative refractive power, and the final lens group Gb is composed of a fifth lens group G5 with positive refractive power.

[0112] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side together with the aperture stop S, and the fifth lens group G5 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 changes.

[0113] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the third lens group G3 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fourth lens group G4 with negative refractive power correspond to the negative lens group GaN.

[0114] The aperture stop S is located on the object side of the fourth lens group G4. The fourth lens group G4 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to a close object, the focusing lens group LF moves along the optical axis toward the image plane independently of the aperture stop S.

[0115] The first lens group G1 is composed of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, and a cemented lens made up of a biconcave lens L3 and a biconvex lens L4.

[0116] The second lens group G2 is composed of a positive meniscus lens L5 whose surface R1 is aspherical and whose convex surface faces the object side, and a cemented lens made up of a biconvex lens L6 and a biconcave lens L7.

[0117] The third lens group G3 is composed of a cemented lens consisting of a negative meniscus lens L8 with its convex surface facing the object side and a biconvex lens L9, and a biconvex lens L10 with aspherical surfaces R1 and R2.

[0118] The fourth lens group G4 is composed of a biconcave lens L11.

[0119] The fifth lens group G5 is composed of a biconvex lens L12, a cemented lens consisting of a biconvex lens L13 and a biconcave lens L14, and a biconvex lens L15 whose surfaces R1 and R2 are aspherical. [Example]

[0120] FIG. 22 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to a fourth embodiment of the present invention.

[0121] The large aperture ratio ultra wide-angle zoom lens of Example 4 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with negative refractive power, and the final lens group Gb is composed of a sixth lens group G6 with positive refractive power.

[0122] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves with respect to the image plane together with the aperture stop S, and the sixth lens group G6 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 changes, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, and the distance between the fifth lens group G5 and the sixth lens group G6 changes.

[0123] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the fourth lens group G4 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fifth lens group G5 with negative refractive power correspond to the negative lens group GaN.

[0124] An aperture stop S is located on the object side of the fifth lens group G5. The third lens group G3 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to an object at a close distance, the focusing lens group LF moves toward the object along the optical axis.

[0125] The first lens group G1 is composed of a cemented lens consisting of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, and a biconcave lens L3 and a positive meniscus lens L4 whose convex surface faces toward the object side.

[0126] The second lens group G2 is composed of a biconvex lens L5.

[0127] The third lens group G3 is composed of a negative meniscus lens L6 with its concave surface facing the object side.

[0128] The fourth lens group G4 is composed of a cemented lens consisting of a negative meniscus lens L7 with its convex surface facing the object side and a biconvex lens L8, and a biconvex lens L9 with an aspherical surface R1.

[0129] The fifth lens group G5 is composed of a cemented lens that includes a biconcave lens L10 and a positive meniscus lens L11 with its convex surface facing the object side.

[0130] The sixth lens group G6 is composed of a cemented lens consisting of a biconvex lens L12, a biconvex lens L13, and a negative meniscus lens L14 with its concave surface facing the object side, and a negative meniscus lens L15 with aspherical surfaces R1 and R2 with its concave surface facing the object side. [Example]

[0131] FIG. 29 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to a fifth embodiment of the present invention.

[0132] The large aperture ratio ultra wide-angle zoom lens of Example 5 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, an aperture stop S, and a fifth lens group G5 with negative refractive power, and the final lens group Gb is composed of a sixth lens group G6 with positive refractive power.

[0133] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 remains fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves with respect to the image plane together with the aperture stop S, and the sixth lens group G6 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 changes, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 increases, and the distance between the fifth lens group G5 and the sixth lens group G6 decreases.

[0134] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the fourth lens group G4 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fifth lens group G5 with negative refractive power correspond to the negative lens group GaN.

[0135] An aperture stop S is located on the object side of the fifth lens group G5. The third lens group G3 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to an object at a close distance, the focusing lens group LF moves toward the object along the optical axis.

[0136] The first lens group G1 is composed of a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with aspherical surfaces R1 and R2 facing the convex surface facing the object side, a biconcave lens L3, and a positive meniscus lens L4 with a convex surface facing the object side.

[0137] The second lens group G2 is composed of a biconvex lens L5 whose surface R1 is aspherical.

[0138] The third lens group G3 is composed of a negative meniscus lens L6 with its concave surface facing the object side.

[0139] The fourth lens group G4 is composed of a cemented lens consisting of a negative meniscus lens L7 with its convex surface facing the object side and a biconvex lens L8, and a biconvex lens L9 with an aspherical surface R1.

[0140] The fifth lens group G5 is composed of a cemented lens that includes a biconcave lens L10 and a positive meniscus lens L11 with its convex surface facing the object side.

[0141] The sixth lens group G6 is composed of a biconvex lens L12, a cemented triplet consisting of a biconvex lens L13, a biconcave lens L14, and a biconvex lens L15, and a negative meniscus lens L16 whose surfaces R1 and R2 are aspherical and whose concave surface faces the object side. [Example]

[0142] FIG. 36 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to Example 6 of the present invention.

[0143] The large aperture ratio ultra wide-angle zoom lens of Example 6 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, an aperture stop S, and a fifth lens group G5 with negative refractive power, and the final lens group Gb is composed of a sixth lens group G6 with positive refractive power.

[0144] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 remains fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 moves with respect to the image plane together with the aperture stop S, and the sixth lens group G6 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 changes, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 increases, and the distance between the fifth lens group G5 and the sixth lens group G6 decreases.

[0145] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the fourth lens group G4 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fifth lens group G5 with negative refractive power correspond to the negative lens group GaN.

[0146] An aperture stop S is located on the object side of the fifth lens group G5. The third lens group G3 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to an object at a close distance, the focusing lens group LF moves toward the object along the optical axis.

[0147] The first lens group G1 is composed of a cemented lens consisting of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, and a biconcave lens L3 and a positive meniscus lens L4 whose convex surface faces toward the object side.

[0148] The second lens group G2 is composed of a biconvex lens L5.

[0149] The third lens group G3 is composed of a plano-concave lens L6 with its concave surface facing the object side.

[0150] The fourth lens group G4 is composed of a cemented lens consisting of a negative meniscus lens L7 with its convex surface facing the object side and a biconvex lens L8, and a biconvex lens L9 with an aspherical surface R1.

[0151] The fifth lens group G5 is composed of a cemented lens that includes a biconcave lens L10 and a positive meniscus lens L11 with its convex surface facing the object side.

[0152] The sixth lens group G6 is composed of a cemented lens consisting of a biconvex lens L12, a biconvex lens L13, and a negative meniscus lens L14 with its concave surface facing the object side, and a negative meniscus lens L15 with aspherical surfaces R1 and R2 with its concave surface facing the object side. [Example]

[0153] FIG. 43 is a lens configuration diagram of a large aperture ratio super wide-angle zoom lens according to Example 7 of the present invention.

[0154] The large aperture ratio ultra wide-angle zoom lens of Example 7 is composed of, in order from the object side, a first lens group G1 with negative refractive power, an intermediate lens group Ga with positive refractive power overall, and a final lens group Gb, the intermediate lens group Ga is composed of a second lens group G2 with positive refractive power, a third lens group G3 with negative refractive power, a fourth lens group G4 with positive refractive power, an aperture stop S, a fifth lens group G5 with negative refractive power, and a sixth lens group G6 with positive refractive power, and the final lens group Gb is composed of a seventh lens group G7 with positive refractive power.

[0155] When changing magnification from the wide-angle end to the telephoto end, the first lens group G1 is fixed with respect to the image plane, the second lens group G2 moves toward the object side, the third lens group G3 moves toward the object side, the fourth lens group G4 moves toward the object side, the fifth lens group G5 changes with respect to the image plane, the sixth lens group G6 moves toward the object side, and the seventh lens group G7 moves toward the object side. In addition, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 changes, the distance between the third lens group G3 and the fourth lens group G4 changes, the distance between the fourth lens group G4 and the fifth lens group G5 changes, the distance between the fifth lens group G5 and the sixth lens group G6 decreases, and the distance between the sixth lens group G6 and the seventh lens group G7 increases.

[0156] The second lens group G2 with positive refractive power corresponds to the first positive lens group GaP1, the fourth lens group G4 with positive refractive power corresponds to the second positive lens group GaP2, and the aperture stop S and the fifth lens group G5 with negative refractive power correspond to the negative lens group GaN.

[0157] An aperture stop S is located on the object side of the fifth lens group G5. The third lens group G3 is composed of a focusing lens group LF with negative refractive power, and when focusing from an object at infinity to an object at a close distance, the focusing lens group LF moves toward the object along the optical axis.

[0158] The first lens group G1 is composed of a cemented lens consisting of a negative meniscus lens L1 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, a negative meniscus lens L2 whose R1 and R2 surfaces are aspherical and whose convex surface faces toward the object side, and a biconcave lens L3 and a positive meniscus lens L4 whose convex surface faces toward the object side.

[0159] The second lens group G2 is composed of a biconvex lens L5.

[0160] The third lens group G3 is composed of a negative meniscus lens L6 with its concave surface facing the object side.

[0161] The fourth lens group G4 is composed of a cemented lens consisting of a negative meniscus lens L7 with its convex surface facing the object side and a biconvex lens L8, and a biconvex lens L9 with an aspherical surface R1.

[0162] The fifth lens group G5 is composed of a cemented lens that includes a biconcave lens L10 and a positive meniscus lens L11 with its convex surface facing the object side.

[0163] The sixth lens group G6 is composed of a biconvex lens L12.

[0164] The seventh lens group G7 is composed of a cemented lens consisting of a biconvex lens L13 and a negative meniscus lens L14 with its concave surface facing the object side, and a negative meniscus lens L15 with aspherical surfaces R1 and R2 with its concave surface facing the object side.

[0165] Numerical examples of the large aperture ratio super wide-angle zoom lens of this embodiment will be described below.

[0166] In [Surface Data], the surface number is the lens surface or aperture stop number counted from the object side, r is the radius of curvature of each surface, d is the spacing between surfaces, nd is the refractive index for the d-line (wavelength 587.56 nm), and vd is the Abbe number for the d-line.

[0167] An asterisk (*) next to a surface number indicates that the lens surface is aspherical, and BF stands for back focal length.

[0168] The (diaphragm) next to the surface number indicates that an aperture diaphragm is located at that position. The radius of curvature for the plane or aperture diaphragm is marked as ∞ (infinity).

[0169] [Aspherical Data] shows the values ​​of each coefficient that determines the aspherical shape of lens surfaces marked with an * in [Surface Data]. The aspherical shape is defined as follows: where y is the displacement from the optical axis in a direction perpendicular to the optical axis, z is the displacement (sag) from the intersection of the aspherical surface and the optical axis in the direction of the optical axis, r is the radius of curvature of the reference sphere, and A4, ..., and A20 are the Conic coefficients of the 20th order aspherical surface, respectively. The coordinates of the aspherical surface are expressed by the following equations:

[0170] TIFF0007819912000001.tif12166

[0171] [Various Data] shows values ​​such as zoom ratio and focal length for each focal length state.

[0172] [Variable Distance Data] shows the variable distance and BF values ​​for each focal length state.

[0173] [Lens Group Data] shows the surface number of each lens group closest to the object and the composite focal length of the entire lens group.

[0174] In the following specification values, the units of length for the listed focal length f, radius of curvature r, spacing d between surfaces, and other lengths are millimeters (mm) unless otherwise specified; however, this is not limited to this, as optical systems can achieve equivalent optical performance with proportional magnification and proportional reduction.

[0175] In the longitudinal and lateral aberration diagrams corresponding to the numerical examples, d, g, and C represent the d-line, g-line, and C-line, respectively, and ΔS and ΔM represent the sagittal and meridional image surfaces, respectively.

[0176] Numerical Example 1 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 200.0000 2.6000 1.76450 49.10 2* 20.2800 9.0000 3* 120.3700 1.9000 1.85135 40.10 4* 45.3400 8.4100 5 -35.8300 1.0000 1.43700 95.10 6 46.3600 0.1500 7 37.9000 6.5700 1.72342 37.99 8 -180.5400 (d8) 9* 45.4900 3.5700 1.51633 64.06 10 -250.2200 0.1500 11 49.6700 6.5000 1.58144 40.89 12 -35.5600 0.9000 1.76385 48.49 13 76.8200 (d13) 14 40.1700 0.9000 1.92286 20.88 15 29.1400 9.5000 1.43700 95.10 16 -29.1400 0.1500 17* 49.7500 3.3300 1.51633 64.06 18* -200.0000 (d18) 19 (Aperture) ∞ (d19) 20 ∞ 0.9000 1.77250 49.62 21 26.2600 (d21) 22 23.3800 6.5800 1.43700 95.10 23 -38.4900 0.3500 24 64.6600 5.7700 1.43700 95.10 25 -22.8100 0.9000 1.61997 63.88 26 22.8100 2.0900 27* 55.3300 2.5000 1.49700 81.54 28* -200.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 3rd page 4th page 9th page K 0.0000 -1.0000 0.0000 -1.0000 0.0000 A4 1.52750E-05 1.37771E-05 -1.31885E-05 -1.74312E-06 -7.98540E-06 A6 -3.78782E-08 1.13452E-08 -1.57132E-08 -1.95179E-08 -1.03000E-08 A8 6.57493E-11 -2.05242E-10 2.67837E-10 4.74824E-10 1.24303E-11 A10 -5.88712E-14 4.69231E-13 -5.06500E-13 -1.07235E-12 -9.00626E-14 A12 1.99797E-17 -3.83415E-16 3.06766E-16 1.61826E-15 0.00000E+00 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 17th page 18th page 27th page 28th page K 0.0000 0.0000 0.0000 0.0000 A4 -7.59671E-06 2.30551E-06 6.56765E-06 2.15611E-05 A6 -2.18858E-08 -3.69282E-08 -1.07508E-07 -1.99424E-07 A8 -3.30499E-10 -1.92376E-10 9.50210E-10 2.92749E-09 A10 1.61084E-12 1.31939E-12 -1.29189E-11 -2.64365E-11 A12 -3.83199E-15 -3.51044E-15 3.67154E-14 7.79005E-14 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 2.05 Wide-angle Mid-range Telephoto Focal length 16.50 24.03 33.89 F-number 2.92 2.92 2.92 Half angle of view ω 55.67 42.47 31.75 Image height Y 21.63 21.63 21.63 Lens total length 136.80 136.80 136.80 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d8 23.1300 9.2800 1.6700 d13 8.8500 6.7654 0.8000 d18 1.0000 2.9200 4.0700 d19 3.5300 3.5300 3.5300 d21 5.8000 13.6700 14.4598 BF 20.7681 26.9127 38.5483 [Lens group data] Group starting plane focal length G1 1 -22.23 G2 9 85.30 G3 14 30.56 G4 20 -33.99 G5 22 58.63 Ga 9 43.79 Gb 22 58.63 GaP1 9 85.30 GaP2 14 30.56 GaN 19 -33.99

[0177] Numerical Example 2 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 137.2800 2.6000 1.76450 49.10 2* 19.1300 9.1400 3* 97.1000 1.9000 1.76450 49.10 4* 45.0900 7.4300 5 -45.4000 1.0000 1.43700 95.10 6 45.4000 0.1500 7 33.8700 6.2500 1.61340 44.27 8 -638.3400 (d8) 9* 50.4600 2.3000 1.69350 53.20 10* 199.2500 0.1500 11 59.1500 5.9600 1.59270 35.45 12 -30.9200 0.9000 1.76385 48.49 13 254.5100 (d13) 14 57.2900 0.9000 1.92286 20.88 15 35.6600 7.2300 1.43700 95.10 16 -35.6600 0.1500 17* 85.4100 4.6500 1.49700 81.54 18* -41.1400 (d18) 19 (Aperture) ∞ (d19) 20 -177.5200 0.9000 1.77250 49.62 21 30.7500 (d21) 22 26.5900 5.7500 1.43700 95.10 23 -37.9500 0.3500 24 43.4400 7.9200 1.43700 95.10 25 -22.8600 0.9000 1.58913 61.25 26 22.8600 2.4500 27* 72.0300 2.1800 1.49700 81.54 28* -200.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 3rd page 4th page 9th page K 0.0000 -1.0000 0.0000 -1.0000 0.0000 A4 1.45840E-05 1.48410E-05 -3.00600E-05 -1.91330E-05 -1.31390E-05 A6 -4.62360E-08 1.82610E-09 9.24890E-08 9.41820E-08 -1.94970E-09 A8 8.88340E-11 -2.66330E-10 -7.94620E-11 1.20130E-10 -3.63100E-10 A10 -8.58600E-14 7.37980E-13 1.05770E-13 -5.39040E-13 1.46820E-12 A12 3.17500E-17 -6.52000E-16 -1.29510E-16 1.40020E-15 0.00000E+00 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 Surfaces 10, 17, 18, 27, 28 K 0.0000 0.0000 0.0000 0.0000 0.0000 A4 -6.15450E-06 -1.43580E-05 -4.62030E-06 -9.50160E-07 1.31331E-05 A6 1.99970E-09 -4.09720E-08 -4.78070E-08 -1.45750E-07 -1.69307E-07 A8 -3.19980E-10 2.12050E-10 3.64790E-10 2.16867E-09 2.85931E-09 A10 1.46280E-12 -1.29940E-12 -2.12460E-12 -2.22910E-11 -2.57337E-11 A12 0.00000E+00 6.9341E-15 8.1000E-15 6.7756E-14 7.77531E-14 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 2.06 Wide-angle Mid-range Telephoto Focal length 16.46 24.04 33.90 F-number 2.91 2.92 2.92 Half angle of view ω 55.60 42.12 31.38 Image height Y 21.63 21.63 21.63 Lens length 133.84 133.84 133.84 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d8 21.8500 8.3000 0.8000 d13 9.1800 6.4004 0.8000 d18 1.0000 3.1200 5.1468 d19 3.6700 3.6700 3.6700 d21 5.8000 12.9200 13.7000 BF 21.2719 28.2163 38.518 [Lens group data] Group starting plane focal length G1 1 -21.82 G2 9 80.33 G3 14 31.93 G4 20 -33.86 G5 22 50.66 Ga 9 46.09 Gb 22 50.66 GaP1 9 80.33 GaP2 14 31.93 GaN 19 -33.86

[0178] Numerical Example 3 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 100.0000 2.6000 1.76450 49.10 2* 17.6900 8.9000 3* 108.0000 1.9000 1.85135 40.10 4* 44.2700 10.4900 5 -37.0000 1.0000 1.43700 95.10 6 22.8100 8.1800 1.54814 45.82 7 -112.0000 (d7) 8* 53.1900 1.7200 1.58313 59.46 9 107.0300 0.1500 10 37.9300 6.7200 1.60342 38.01 11 -26.5700 0.9000 1.78590 43.93 12 560.0000 (d12) 13 48.8200 0.9000 1.92286 20.88 14 32.1200 7.1700 1.43700 95.10 15 -30.3200 0.1500 16* 68.0200 3.1800 1.49700 81.54 17* -85.2400 (d17) 18 (Aperture) ∞ (d18) 19 -342.2400 0.9000 1.77250 49.62 20 29.3900 (d20) 21 22.7500 6.9000 1.43700 95.10 22 -35.9600 0.7700 23 64.8000 7.0800 1.43700 95.10 24 -18.6200 0.9000 1.65160 58.54 25 24.5400 1.5900 26* 39.1000 2.9700 1.49700 81.54 27* -200.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 3rd page 4th page 8th page K 0.00000E+00 -1.0000 0.0000 -1.0000 0.0000 A4 9.76980E-06 1.08100E-05 -2.34580E-05 -1.46160E-05 -8.36520E-06 A6 -3.41530E-08 1.24860E-08 7.78070E-08 8.53450E-08 -4.57680E-09 A8 6.98390E-11 -3.69840E-10 -8.50120E-11 1.43830E-10 -3.17490E-11 A10 -6.55930E-14 1.05150E-12 1.18060E-13 -6.71690E-13 -2.13550E-14 A12 2.22900E-17 -9.38870E-16 -1.14360E-16 1.52330E-15 0.00000E+00 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 16th page 17th page 26th page 27th page K 0.0000 0.0000 0.0000 0.0000 A4 -1.27820E-05 -4.10460E-06 -5.70460E-06 1.79370E-05 A6 -6.24070E-08 -6.59550E-08 6.07650E-08 -4.13180E-08 A8 4.18400E-10 5.35440E-10 -9.91190E-10 1.13350E-09 A10 -3.84810E-12 -4.40830E-12 0.00000E+00 -1.41270E-11 A12 1.50780E-14 1.66180E-14 0.00000E+00 4.01780E-14 A14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 1.76 Wide-angle Mid-range Telephoto Focal length 15.49 22.02 27.29 F-number 2.92 2.92 2.92 Half angle of view ω 57.44 44.50 37.36 Image height Y 21.63 21.63 21.63 Lens length 130.74 130.74 130.74 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d7 16.6400 5.5600 0.8000 d12 7.8200 4.1224 0.8000 d17 1.0000 2.9800 4.2800 d18 3.6200 3.6200 3.6200 d20 5.8000 11.9422 12.8433 BF 20.7923 27.4476 33.3289 [Lens group data] Group starting plane focal length G1 1 -19.23 G2 8 72.11 G3 13 32.97 G4 19 -35.00 G5 21 50.26 Ga 8 43.34 Gb 21 50.26 GaP1 8 72.11 GaP2 13 32.97 GaN 18 -35.00

[0179] Numerical Example 4 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 200.0000 2.2000 1.76450 49.10 2* 23.5000 7.1600 3* 200.0000 1.8000 1.77377 47.17 4* 25.2600 6.9900 5 -47.6800 1.0000 1.43700 95.10 6 29.8000 4.1500 1.85451 25.15 7 187.2500 (d7) 8 41.3700 4.4500 1.51742 52.15 9 -71.4700 (d9) 10 -50.0000 0.8000 2.00069 25.46 11 -217.9200 (d11) 12 32.4800 0.9000 1.92286 20.88 13 24.8500 6.5700 1.43700 95.10 14 -59.4100 0.1500 15* 30.9500 5.6500 1.49700 81.54 16 -70.5200 (d16) 17 (Aperture) ∞ 3.3300 18 -63.0900 0.8000 1.77250 49.62 19 33.8700 1.9400 1.94595 17.98 20 75.9100 (d20) 21 22.0000 7.3300 1.43700 95.10 22 -28.6300 0.8300 23 1011.4200 3.4600 1.43700 95.10 24 -32.0400 0.8500 1.95375 32.32 25 -230.9400 3.0400 26* -59.0300 1.2000 1.85135 40.10 27* -200.0000 (BF) Image plane ∞ [Aspherical data] 1 side 2 sides 3 sides 4 sides 15 sides K 0.0000 -1.0000 -100.0000 0.0000 0.0000 A4 4.10420E-05 3.45290E-05 0.00000E+00 2.41000E-05 -8.04810E-06 A6 -9.32260E-08 -1.41780E-08 0.00000E+00 3.31720E-07 -2.10640E-08 A8 5.76750E-11 5.06840E-10 0.00000E+00 -1.34390E-08 8.25000E-11 A10 1.01440E-13 -8.40330E-12 0.00000E+00 2.88050E-10 -3.31350E-13 A12 -1.03960E-16 3.01460E-14 0.00000E+00 -3.61300E-12 0.00000E+00 A14 0.00000E+00 -3.20960E-17 0.00000E+00 2.83010E-14 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 -1.34940E-16 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 3.55850E-19 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 -3.96910E-22 0.00000E+00 26 sides and 27 sides K 0.0000 0.0000 A4 -1.82430E-04 -1.36770E-04 A6 1.13080E-06 1.24130E-06 A8 -3.03260E-09 -3.57460E-09 A10 8.36320E-13 3.93740E-12 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 1.65 Wide-angle Mid-range Telephoto Focal length 16.50 21.97 27.30 F-number 2.92 2.92 2.93 Half angle of view ω 55.22 44.24 38.06 Image height Y 21.63 21.63 21.63 Lens total length 119.18 119.18 119.18 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d7 11.6500 1.8700 1.5000 d9 6.0000 8.3916 6.0183 d11 4.8100 6.0900 3.0000 d16 1.9500 8.2500 7.5200 d20 7.0500 2.5200 0.8000 BF 23.1183 27.4567 35.7400 [Lens group data] Group starting plane focal length G1 1 -16.40 G2 8 51.33 G3 10 -65.00 G4 12 27.01 G5 18 -50.73 G6 21 58.00 Ga 8 36.28 Gb 21 58.00 GaP1 8 51.33 GaP2 12 27.01 GaN 17 -50.73

[0180] Numerical Example 5 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1 49.0000 1.6000 1.75500 52.32 2 18.1500 4.9300 3* 50.6200 1.6000 1.76450 49.10 4* 20.1700 9.3500 5 -43.1700 1.0000 1.43700 95.10 6 56.1200 0.4700 7 36.7600 2.3700 1.92286 20.88 8 68.4400 (d8) 9* 33.7500 3.9000 1.59201 67.02 10 -197.0400 (d10) 11 -51.4800 0.8000 2.00069 25.46 12 -248.7100 (d12) 13 37.2500 0.9000 1.85451 25.15 14 27.3300 6.0000 1.43700 95.10 15 -50.0000 0.1500 16* 47.3500 3.8800 1.69350 53.20 17 -85.1200 (d17) 18 (Aperture) ∞ 2.5500 19 -71.1400 0.8000 1.75500 52.32 20 37.7000 1.6000 1.94595 17.98 21 72.0000 (d21) 22 24.0800 5.9200 1.43700 95.10 23 -31.3000 0.7400 24 43.2900 5.1600 1.43700 95.10 25 -26.5100 0.8500 1.80611 40.73 26 34.4600 4.3700 1.43700 95.10 27 -117.4000 1.7700 28* -47.3700 1.2000 1.85135 40.10 29* -100.0000 (BF) Image plane ∞ [Aspherical data] 3 sides 4 sides 9 sides 16 sides 28 sides K 0.0000 -1.0000 0.0000 0.0000 0.0000 A4 1.51500E-04 1.68600E-04 -4.73640E-06 -6.39981E-06 -1.35500E-04 A6 -1.56170E-06 -1.37550E-06 -6.02800E-10 -9.04204E-09 8.12280E-07 A8 1.34460E-08 4.84050E-09 1.73480E-11 1.99204E-11 -1.73050E-09 A10 -7.86830E-11 9.96990E-11 0.00000E+00 -8.34524E-14 0.00000E+00 A12 2.62350E-13 -1.87250E-12 0.00000E+00 0.00000E+00 0.00000E+00 A14 -2.52440E-16 1.49095E-14 0.00000E+00 0.00000E+00 0.00000E+00 A16 -1.28680E-18 -6.42984E-17 0.00000E+00 0.00000E+00 0.00000E+00 A18 4.57220E-21 1.46277E-19 0.00000E+00 0.00000E+00 0.00000E+00 A20 -4.57780E-24 -1.37840E-22 0.00000E+00 0.00000E+00 0.00000E+00 29 sides K 0.0000 A4 -9.31410E-05 A6 4.75160E-07 A8 1.66190E-08 A10 -5.04660E-10 A12 8.40420E-12 A14 -8.61320E-14 A16 5.29700E-16 A18 -1.78290E-18 A20 2.50780E-21 [Various data] Zoom ratio 1.65 Wide-angle Mid-range Telephoto Focal length 16.52 21.98 27.24 F-number 2.92 2.92 2.91 Half angle of view ω 54.50 43.38 37.04 Image height Y 21.63 21.63 21.63 Lens length 115.33 115.33 115.33 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d8 12.3900 4.3100 1.5000 d10 7.4400 7.9449 6.4396 d12 3.0000 3.8000 3.0000 d17 2.0700 9.8500 12.5900 d21 7.9700 4.6400 1.5300 BF 20.5533 22.8784 28.3637 [Lens group data] Group starting plane focal length G1 1 -16.30 G2 9 48.98 G3 11 -65.00 G4 13 26.76 G5 19 -53.23 G6 22 55.27 Ga 9 36.31 Gb 22 55.27 GaP1 9 48.98 GaP2 13 26.76 GaN 18 -53.23

[0181] Numerical Example 6 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 200.0000 2.2000 1.76450 49.10 2* 23.5000 7.9400 3* 182.2900 1.6000 1.85135 40.10 4* 26.5600 6.8100 5 -42.0000 1.0000 1.43700 95.10 6 26.2500 4.8200 1.68430 26.81 7 3477.2700 (d7) 8 52.0800 3.2000 1.60342 38.01 9 -114.7400 (d9) 10 -65.0500 0.8000 2.00069 25.46 11∞ (d11) 12 43.1300 0.9000 1.92286 20.88 13 27.8300 4.7700 1.43700 95.10 14 -82.5700 0.1500 15* 33.9300 5.1500 1.58313 59.46 16 -54.6300 (d16) 17 (Aperture) ∞ 3.1700 18 -45.1500 0.8000 1.77250 49.62 19 36.1000 1.8800 1.94595 17.98 20 85.8600 (d20) 21 20.7800 7.9500 1.43700 95.10 22 -35.2200 0.3200 23 38.4200 7.2100 1.43700 95.10 24 -20.7400 0.8500 1.91082 35.25 25 -100.7600 6.2500 26* -63.8500 1.2000 1.85135 40.10 27* -200.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 3rd page 4th page 15th page K 0.0000 -1.0000 -100.0000 0.0000 0.0000 A4 7.05270E-05 6.89600E-05 0.00000E+00 2.34430E-05 -5.84070E-06 A6 -2.63130E-07 1.04110E-08 0.00000E+00 -1.18990E-07 -1.30000E-08 A8 5.46340E-10 -1.33870E-09 0.00000E+00 -3.74410E-10 8.85650E-11 A10 -6.21830E-13 1.74820E-12 0.00000E+00 7.03670E-11 -2.88950E-13 A12 3.41910E-16 5.20340E-15 0.00000E+00 -1.25190E-12 0.00000E+00 A14 0.00000E+00 -7.87170E-18 0.00000E+00 1.17290E-14 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 -6.23560E-17 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 1.76010E-19 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 -2.04950E-22 0.00000E+00 26th page 27th page K 0.0000 0.0000 A4 -1.42484E-04 -1.02220E-04 A6 5.50460E-07 6.94070E-07 A8 -8.96790E-10 -1.40050E-09 A10 -1.94470E-12 1.26580E-12 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 1.62 Wide-angle Mid-range Telephoto Focal length 14.43 18.01 23.35 F-number 2.92 2.92 2.92 Half angle of view ω 58.90 50.08 41.87 Image height Y 21.63 21.63 21.63 Lens total length 120.03 120.03 120.03 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d7 11.1000 4.1200 1.5000 d9 6.0000 7.3756 6.0748 d11 3.0000 4.4700 3.0000 d16 2.2500 7.3500 9.1000 d20 7.7900 4.1000 0.8000 BF 20.9193 23.6437 30.5845 [Lens group data] Group starting plane focal length G1 1 -15.59 G2 8 59.80 G3 10 -65.00 G4 12 28.14 G5 18 -42.55 G6 21 35.04 Ga 8 48.45 Gb 21 35.04 GaP1 8 59.80 GaP2 12 28.14 GaN 17 -42.55

[0182] Numerical Example 7 Unit: mm [Face Data] Surface number rd nd vd Object surface ∞ (d0) 1* 200.0000 2.2000 1.76450 49.10 2* 23.5000 7.8400 3* 200.0000 1.8000 1.80610 40.73 4* 27.3600 5.7700 5 -58.3700 1.0000 1.43700 95.10 6 24.7400 4.0100 1.85451 25.15 7 89.9200 (d7) 8 48.4400 3.2500 1.63930 44.87 9 -122.5900 (d9) 10 -50.5500 0.8000 2.00069 25.46 11 -228.5500 (d11) 12 32.3700 0.9000 1.92286 20.88 13 23.6800 6.2800 1.43700 95.10 14 -66.1400 0.1500 15* 34.3200 5.3200 1.55332 71.68 16 -56.1500 (d16) 17 (Aperture) ∞ 3.6700 18 -65.5600 0.8000 1.77250 49.62 19 35.3600 1.9300 1.94595 17.98 20 80.0000 (d20) 21 22.0000 7.0800 1.43700 95.10 22 -29.7500 (d22) 23 89.1400 4.8000 1.43700 95.10 24 -24.0600 0.8500 1.90043 37.37 25 -1228.0000 3.8200 26* -63.2500 1.2000 1.85135 40.10 27* -200.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 3rd page 4th page 15th page K 0.0000 -1.0000 -100.0000 0.0000 0.0000 A4 6.83270E-05 7.11160E-05 0.00000E+00 2.01220E-05 -8.30040E-06 A6 -2.32410E-07 -2.53490E-08 0.00000E+00 2.89480E-07 -1.59340E-08 A8 4.64070E-10 -3.50700E-10 0.00000E+00 -1.40200E-08 7.04530E-11 A10 -4.93710E-13 -3.35910E-12 0.00000E+00 3.49220E-10 -2.81540E-13 A12 2.47700E-16 1.84630E-14 0.00000E+00 -4.95300E-12 0.00000E+00 A14 0.00000E+00 -2.42660E-17 0.00000E+00 4.34810E-14 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 -2.31920E-16 0.00000E+00 A18 0.00000E+00 0.00000E+00 0.00000E+00 6.87310E-19 0.00000E+00 A20 0.00000E+00 0.00000E+00 0.00000E+00 -8.66840E-22 0.00000E+00 Page 26 Page 27 K 0.0000 0.0000 A4 -1.69860E-04 -1.25260E-04 A6 9.87260E-07 1.09070E-06 A8 -2.15780E-09 -2.56960E-09 A10 -1.98440E-12 9.15630E-13 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 A18 0.00000E+00 0.00000E+00 A20 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 1.66 Wide-angle Mid-range Telephoto Focal length 16.50 21.96 27.31 F-number 2.92 2.92 2.92 Half angle of view ω 53.63 43.48 37.45 Image height Y 21.63 21.63 21.63 Lens length 115.71 115.71 115.71 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d7 12.8400 2.9100 1.5000 d9 6.0000 8.4076 5.9706 d11 3.0000 4.6300 3.0000 d16 1.8700 7.6700 7.3500 d20 7.1000 2.6300 0.8000 d22 0.5000 0.8300 1.0000 BF 20.9252 25.1576 32.6146 [Lens group data] Group starting plane focal length G1 1 -16.40 G2 8 54.72 G3 10 -65.01 G4 12 26.20 G5 18 -53.14 G6 21 30.20 G7 23 -43.82 Ga 8 29.73 Gb 23 -43.82 GaP1 8 54.72 GaP2 12 26.20 GaN 17 -53.14

[0183] Also shown is a list of values ​​corresponding to the conditional expressions in each of these embodiments.

[0184] [Conditional expression corresponding value] Conditional Expression Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 (1) -0.78 -0.73 -0.81 -1.79 -1.79 -1.34 -2.19 (2) 111.338 111.202 114.881 110.433 109.007 117.798 107.269 (3) -1.97 -2.11 -2.25 -2.21 -2.23 -3.11 -1.81 (4) 1.80 2.07 1.67 1.02 1.07 1.06 1.04 (5) 1.765 1.765 1.765 1.765 1.755 1.765 1.765 (6) 49.10 49.10 49.10 49.10 52.32 49.10 49.10 (7) 1.851 1.765 1.851 1.774 1.765 1.851 1.806 (8) 40.10 49.10 40.10 47.17 49.10 40.10 40.73 (9) -1.00 -1.00 -1.28 -1.86 -1.95 -1.82 -1.95 (10) 0.55 0.57 0.54 0.50 0.48 0.51 0.51 (11) 1.95 1.74 1.66 1.41 1.35 1.23 1.84 (12) 0.70 0.69 0.63 0.74 0.74 0.58 0.88 [Explanation of symbols]

[0185] G1 First lens group G2 Second lens group G3 Third lens group G4 4th lens group G5 5th lens group G6 6th lens group G7 7th lens group Ga intermediate lens group Gb Final lens group LF focusing lens group L1 First lens L2 Second lens GaP1: First positive lens group in the intermediate lens group Ga GaP2: Second positive lens group in the intermediate lens group Ga GaN Negative lens group with aperture stop S of intermediate lens group Ga S aperture stop I image plane

Claims

1. a first lens group G1 having a negative refractive power, an intermediate lens group Ga having a positive refractive power overall, and a final lens group Gb having a positive or negative refractive power, the intermediate lens group Ga consisting of 3 to 5 lens groups, including a first positive lens group GaP1 and an aperture stop S located closest to the object, a second positive lens group GaP2 located closer to the object than the aperture stop S, and a focusing lens group LF having a negative refractive power that moves on the optical axis when focusing from an object at infinity to an object at a close distance, the first lens group G1 being fixed with respect to an image plane, the intermediate lens group Ga moving, the distance between the first lens group G1 and the intermediate lens group Ga decreasing, and the distance between the intermediate lens group Ga and the final lens group Gb changing, the large aperture ratio ultra wide-angle zoom lens being characterized by satisfying the following conditional expression: (1) 0.3<|fLF / faw|<3.0 (2) 100.00°<2ωw faw: focal length of the intermediate lens group Ga at the wide-angle end when the object distance is infinity fLF: focal length of the focusing lens group LF 2ωw: Maximum angle of view of the entire system when the object distance is infinite at the wide-angle end

2. 2. The large aperture ratio ultra-wide-angle zoom lens according to claim 1, wherein the first lens group G1 and the intermediate lens group Ga satisfy the following conditional expression: 1<G<1<Ga<1. (3) 1.0<|faw / f1|<5.0 f1: focal length of the first lens group G1 faw: focal length of the intermediate lens group Ga at the wide-angle end when the object distance is infinity

3. 3. The large aperture ratio ultra-wide-angle zoom lens according to claim 1, wherein the first lens group G1 comprises, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, and a negative meniscus lens L2 having an aspherical surface and having a convex surface facing the object side, and wherein the following conditional expression is satisfied: (4) 1.00<((L2R1+L2R2) / (L2R1-L2R2)) / ((L1R1+L1R2) / (L1R1-L1R2))<3.00 (5) L1nd>1.70 (6) L1νd>40.0 (7) L2nd>1.70 (8) L2νd>35.0 L1R1: radius of curvature of the R1 surface of the negative meniscus lens L1 L1R2: Radius of curvature of the R2 surface of the negative meniscus lens L1 L2R1: radius of curvature of the R1 surface of the negative meniscus lens L2 L2R2: radius of curvature of the R2 surface of the negative meniscus lens L2 L1nd: refractive index of the negative meniscus lens L1 L1νd: Abbe number of the negative meniscus lens L1 L2nd: refractive index of the negative meniscus lens L2 L2νd: Abbe number of the negative meniscus lens L2

4. 4. The large aperture ratio ultra-wide-angle zoom lens according to claim 1, wherein the intermediate lens group Ga includes a negative lens group GaN that moves integrally with the aperture stop S while positioning the aperture stop S on the object side during zooming from the wide-angle end to the telephoto end, and the following conditional expression is satisfied: (9) 0.5<|faN / ft|<5.0 f aN: focal length of the negative lens group GaN ft: focal length of the entire system at the telephoto end when the object distance is infinity

5. 5. The large aperture ratio ultra-wide-angle zoom lens according to claim 1, wherein the aperture stop S satisfies the following condition at the telephoto end: 1 / 2<1 / 2<1 / 2 . (10) 0.2<SPLt / LT<0.9 SPLt: distance from the aperture stop S to the image plane at the telephoto end LT: distance from the surface of the first lens group G1 closest to the object to the image plane

6. A large aperture ratio ultra-wide-angle zoom lens as described in any one of claims 1 to 5, characterized in that when changing magnification from the wide-angle end to the telephoto end, the first positive lens group GaP1 moves toward the object side, and the following conditional expression is satisfied: (11) 1.0<faP1 / faw<3.0 faP1: focal length of the first positive lens group GaP1 faw: focal length of the intermediate lens group Ga at the wide-angle end when the object distance is infinity

7. A large aperture ratio ultra-wide-angle zoom lens as described in any one of claims 1 to 6, characterized in that when changing magnification from the wide-angle end to the telephoto end, the second positive lens group GaP2 moves toward the object side, and the following conditional expression is satisfied: (12) 0.3<faP2 / faw<1.5 faP2: focal length of the second positive lens group GaP2 faw: focal length of the intermediate lens group Ga at the wide-angle end when the object distance is infinity

8. 8. An imaging device comprising the large aperture ratio super wide-angle zoom lens according to claim 1.

Images