Image capturing lens and image capturing device

Abstract

To provide an image capturing lens which offers a small F-number, a wide angle of view, a compact configuration, and good optical performance, and to provide an image capturing device having the image capturing lens.SOLUTION: An image capturing lens is provided, consisting of a front group, an aperture stop, and a rear group in order from the object side to the image side. The rear group includes one or two focusing lens groups configured to move along an optical axis when focusing. While focusing, an optical axial distance from the most object-side lens surface of the front group to the image plane is fixed. The image capturing lens satisfies predefined conditional expressions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology of the present disclosure relates to an imaging lens and an imaging device.

Background Art

[0002] Conventionally, as an imaging lens that can be used in an imaging device such as a digital camera, the imaging optical system described in Patent Document 1 below is known.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for an imaging lens that has a small F-number, a wide angle, a small size, and maintains good optical performance. These required levels are increasing year by year.

[0005] The present disclosure provides an imaging lens that has a small F-number, a wide angle, a small size, and maintains good optical performance, and an imaging device including this imaging lens.

Means for Solving the Problems

[0006] A first aspect of the present disclosure is an imaging lens including, in order from the object side to the image side, a front group, an aperture stop, and a rear group, the rear group including one or two focusing lens groups that move along the optical axis during focusing, and during focusing, the distance on the optical axis from the most object-side lens surface of the front group to the image plane is invariant, 2.3 < TL / (f × tanωm) < 7 (1) 1.15 < Fno / tanωm < 3.5 (2) 0.3 < Bf / (f × tanωm) < 1.5 (3) It satisfies the conditional expressions (1), (2), and (3) represented by Here, TL is the sum of the distance on the optical axis from the most object-side lens surface of the front group to the most image-side lens surface of the rear group and the back focus at the air-equivalent distance of the entire system in the state of focusing on an infinite object. f is the focal length of the entire system in the state of focusing on an infinite object. ωm is the maximum half field angle in the state of focusing on an infinite object. Fno is the aperture F-number in the state of focusing on an infinite object. Bf is the back focus at the air-equivalent distance of the entire system in the state of focusing on an infinite object.

[0007] In the second aspect of the present disclosure, in the imaging lens of the first aspect, when the distance on the optical axis from the most object-side lens surface of the front group to the aperture stop in the state of focusing on an infinite object is defined as dFSt, 0.43 < dFSt / TL < 0.75 (4) It satisfies the conditional expression (4) represented by

[0008] In the third aspect of the present disclosure, in the imaging lens of the first aspect, when the focal length of the front group in the state of focusing on an infinite object is fF and the focal length of the rear group in the state of focusing on an infinite object is fR, -2 < fR / fF < 4 (5) It satisfies the conditional expression (5) represented by

[0009] In the fourth aspect of the present disclosure, in the imaging lens of the first aspect, when the focal length of the front group in the state of focusing on an infinite object is fF, -1 < f / fF < 2 (6) It satisfies the conditional expression (6) represented by

[0010] In the fifth aspect of the present disclosure, in the imaging lens of the first aspect, 6 < (TL × Fno) / (f × tanωm) < 11 (7) It satisfies the conditional expression (7) represented by

[0011] In a sixth aspect of the present disclosure, in the imaging lens of the first aspect, the front group includes one focusing lens group that moves along the optical axis during focusing.

[0012] In a seventh aspect of the present disclosure, in the imaging lens of the first aspect, the rear group includes two focusing lens groups that move while changing the mutual interval during focusing.

[0013] In an eighth aspect of the present disclosure, in the imaging lens of the first aspect, at least one lens having an inflection point on the object-side lens surface, which has a convex surface facing the object side in the paraxial region and whose concavo-convex shape changes midway from the optical axis toward the peripheral part, is arranged in the rear group.

[0014] In a ninth aspect of the present disclosure, in the imaging lens of the first aspect, at least one lens having an inflection point on the object-side lens surface, which has a concave surface facing the object side in the paraxial region and whose concavo-convex shape changes midway from the optical axis toward the peripheral part, is arranged in the rear group.

[0015] In a tenth aspect of the present disclosure, in the imaging lens of the first aspect, at least one lens having an inflection point on the image-side lens surface, which has a convex surface facing the image side in the paraxial region and whose concavo-convex shape changes midway from the optical axis toward the peripheral part, is arranged in the rear group.

[0016] In an eleventh aspect of the present disclosure, in the imaging lens of the first aspect, at least one lens having an inflection point on the image-side lens surface, which has a concave surface facing the image side in the paraxial region and whose concavo-convex shape changes midway from the optical axis toward the peripheral part, is arranged in the rear group.

[0017] In a twelfth aspect of the present disclosure, in the imaging lens of the first aspect, a three-piece cemented lens joined in the order of a first positive lens, a second positive lens, and a negative lens is included.

[0018] In a thirteenth aspect of the present disclosure, in the imaging lens of the twelfth aspect, the surface of the second positive lens on the first positive lens side faces the first positive lens side with a concave surface.

[0019] The 14th aspect of the present disclosure is that in the imaging lens of the 1st aspect, 3.5 < TL / (f × tan ωm) < 5.6 (1-1) satisfies the conditional expression (1-1) represented by the above formula.

[0020] The 15th aspect of the present disclosure is that in the imaging lens of the 1st aspect, 1.3 < Fno / tan ωm < 2.7 (2-1) satisfies the conditional expression (2-1) represented by the above formula.

[0021] The 16th aspect of the present disclosure is that in the imaging lens of the 15th aspect, 3.5 < TL / (f × tan ωm) < 5.6 (1-1) satisfies the conditional expression (1-1) represented by the above formula.

[0022] The 17th aspect of the present disclosure is that in the imaging lens of the 16th aspect, 6 < (TL × Fno) / (f × tan ωm) < 11 (7) satisfies the conditional expression (7) represented by the above formula.

[0023] The 18th aspect of the present disclosure is that the imaging lens of the 17th aspect includes a three-piece cemented lens in which a first positive lens, a second positive lens, and a negative lens are cemented in this order.

[0024] The 19th aspect of the present disclosure is that in the imaging lens of the 18th aspect, the surface of the second positive lens on the first positive lens side faces the first positive lens side with a concave surface.

[0025] The 20th aspect of the present disclosure is that the imaging lens of the 17th aspect includes one focusing lens group that moves along the optical axis during focusing in the front group.

[0026] The 21st aspect of the present disclosure is that in the imaging lens of the 20th aspect, at least one lens having a convex surface facing the object side in the paraxial region and having an inflection point on the lens surface on the object side where the concavo-convex shape changes halfway from the optical axis to the peripheral portion is arranged in the rear group.

[0027] The 22nd aspect of the present disclosure is that in the imaging lens of the 17th aspect, the rear group includes two focusing lens groups that move while changing the mutual distance during focusing.

[0028] The 23rd aspect of the present disclosure is that in the imaging lens of the 22nd aspect, at least one lens having a bending point on the object-side lens surface, which has a convex surface facing the object side in the paraxial region and whose concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group.

[0029] The 24th aspect of the present disclosure is that in the imaging lens of the 17th aspect, at least one lens having a bending point on the object-side lens surface, which has a concave surface facing the object side in the paraxial region and whose concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group.

[0030] The 25th aspect of the present disclosure is that in the imaging lens of the 17th aspect, 4.4 < TL / (f × tanωm) < 5.2 (1-2) satisfies the conditional expression (1-2) represented by the above.

[0031] The 26th aspect of the present disclosure is that in the imaging lens of the 25th aspect, 6.3 < (TL × Fno) / (f × tanωm) < 9.5 (7-1) satisfies the conditional expression (7-1) represented by the above.

[0032] The 27th aspect of the present disclosure is that in the imaging lens of the 26th aspect, at least one lens having a bending point on the image-side lens surface, which has a convex surface facing the image side in the paraxial region and whose concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group.

[0033] The 28th aspect of the present disclosure is that in the imaging lens of the 17th aspect, at least one lens having a bending point on the image-side lens surface, which has a concave surface facing the image side in the paraxial region and whose concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group.

[0034] The 29th aspect of the present disclosure is that in the imaging lens of the 1st aspect, the rear group includes at least one aspherical lens. When the most image-side aspherical lens among the aspherical lenses included in the rear group is defined as the most image-side aspherical lens, 0.2 < |(1 / Rcf - 1 / Rcr) / (1 / Ryf - 1 / Ryr)| < 4 (8) satisfies the conditional expression (8) represented by Here, the paraxial curvature radius of the object-side surface of the most image-side aspherical lens is defined as Rcf. The curvature radius at the position of the maximum effective diameter of the object-side surface of the most image-side aspherical lens is defined as Ryf. The paraxial curvature radius of the image-side surface of the most image-side aspherical lens is defined as Rcr. The curvature radius at the position of the maximum effective diameter of the image-side surface of the most image-side aspherical lens is defined as Ryr.

[0035] The 30th aspect of the present disclosure is that in the imaging lens of the 1st aspect, the number of focusing lens groups included in the imaging lens is two, 0.2 < |ff1 / ff2| < 5 (9) satisfies the conditional expression (9) represented by Here, among the two focusing lens groups included in the imaging lens, the focal length of the object-side focusing lens group is defined as ff1. Among the two focusing lens groups included in the imaging lens, the focal length of the image-side focusing lens group is defined as ff2.

[0036] The 31st aspect of the present disclosure is that in the imaging lens of the 1st aspect, when the combined focal length of all the lenses on the image side of the most image-side focusing lens group included in the imaging lens is defined as ffR, -1.5 < f / ffR < 1.5 (10) satisfies the conditional expression (10) represented by

[0037] The 32nd aspect of the present disclosure is an imaging device including the imaging lens according to any one of the 1st to 31st aspects.

[0038] In addition, the expressions "comprising ~" and "consisting of ~" in this specification are intended to mean that, in addition to the recited components, there may be included lenses that substantially have no refractive power, optical elements other than lenses such as diaphragms, filters, and cover glasses, and mechanical parts such as lens flanges, lens barrels, imaging elements, and shake correction mechanisms, and the like.

[0039] The "group having a positive refractive power" in this specification means that the group as a whole has a positive refractive power. Similarly, the "group having a negative refractive power" means that the group as a whole has a negative refractive power. The "lens having a positive refractive power" and the "positive lens" are synonymous. The "lens having a negative refractive power" and the "negative lens" are synonymous. The "~ group" in this specification is not limited to a configuration consisting of a plurality of lenses, and may also be a configuration consisting of only one lens.

[0040] The "entire system" in this specification means the imaging lens. The "focal length" used in the conditional expression is the paraxial focal length. The "distance on the optical axis" used in the conditional expression is the geometric distance unless otherwise specified. The values used in the conditional expression are the values based on the d-line in the state of focusing on an infinite object unless otherwise specified.

[0041] Regarding the radius of curvature, sign of refractive power, and surface shape of a lens including an aspherical surface, those in the paraxial region are used unless otherwise specified. The sign of the radius of curvature is positive for the radius of curvature of a surface convex toward the object side and negative for the radius of curvature of a surface convex toward the image side.

[0042] The "d-line", "C-line", and "F-line" described in this specification are spectral lines, and the wavelength of the d-line is treated as 587.56 nm (nanometers), the wavelength of the C-line is treated as 656.27 nm (nanometers), and the wavelength of the F-line is treated as 486.13 nm (nanometers).

Advantages of the Invention

[0043] According to the present disclosure, it is possible to provide an imaging lens having a small F number, a wide angle, a small size, and maintaining good optical performance, and an imaging device including this imaging lens.

Brief Description of the Drawings

[0044]

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Mode for Carrying Out the Invention

[0045] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0046] FIG. 1 shows a cross-sectional view of the configuration of an imaging lens according to an embodiment of the present disclosure. FIG. 2 shows a cross-sectional view of the configuration of the imaging lens of FIG. 1 and the light beam. In FIG. 2, the upper part marked with "infinity" shows the state of focusing on an infinite object, and the lower part marked with "close distance" shows the state of focusing on a close-distance object. The state of the lower part of FIG. 2 is a state where the absolute value of the shooting magnification is 0.16 times. In FIG. 2, as the light beam, the on-axis light beam and the light beam with the maximum semi-aperture angle ωm in the state of focusing on an infinite object, and the on-axis light beam and the light beam with the maximum semi-aperture angle in the state of focusing on a close-distance object are shown. In FIGS. 1 and 2, the left side is the object side, and the right side is the image side. The examples shown in FIGS. 1 and 2 correspond to the imaging lens of Example 1 described later. Hereinafter, the description will mainly refer to FIG. 1.

[0047] The imaging lens of the present disclosure includes, in order from the object side to the image side along the optical axis Z, a front group GF, a diaphragm St, and a rear group GR. Each of the front group GF and the rear group GR includes one or more lenses.

[0048] As an example, each group of the imaging lens in FIG. 1 is configured as follows. The front group GF consists of five lenses L11 to L15 in order from the object side to the image side. The rear group GR consists of eight lenses L21 to L28 in order from the object side to the image side. The diaphragm St in FIG. 1 indicates the position in the optical axis direction, rather than the size or shape. This illustration method of the diaphragm St is the same in other cross-sectional views.

[0049] It may be configured such that a negative meniscus lens with a convex surface facing the object side is arranged on the most object side of the front group GF. In this case, it is advantageous for wide-angle conversion.

[0050] The positive lens may be arranged on the most image side of the front group GF. In this case, it is advantageous for correcting spherical aberration. In this case, the positive lens on the most image side of the front group GF may be configured to have a biconvex shape. In this case, it is more advantageous for correcting spherical aberration.

[0051] The imaging lens of the present disclosure has an autofocus function. However, in the imaging lens of the present disclosure, when focusing, the distance on the optical axis from the lens surface on the most object side of the front group GF to the image plane Sim is invariant. According to this configuration, fluctuations in the center of gravity during focusing can be suppressed, so that the convenience during shooting can be enhanced.

[0052] Hereinafter, a lens group that moves along the optical axis Z during focusing is referred to as a focusing lens group. The rear group GR of the present disclosure includes one or two focusing lens groups that move along the optical axis Z during focusing. By moving the lens group of the rear group GR during focusing, fluctuations in the angle of view during focusing can be suppressed.

[0053] As an example, the rear group GR of the imaging lens in the example of FIG. 1 includes one focusing lens group. The focusing lens group in the example of FIG. 1 is composed of lenses L21 to L26. The parentheses described below the imaging lens in FIG. 1 indicate the focusing lens group, and the arrow attached to this parentheses indicates the moving direction during focusing from an infinite object to a close-distance object.

[0054] Note that the example shown in FIG. 1 is just an example, and the imaging lens of the present disclosure can be variously modified without departing from the gist of the technology of the present disclosure.

[0055] For example, the front group GF may be configured to include one focusing lens group that moves along the optical axis Z during focusing. In this case, it becomes easy to suppress fluctuations in field curvature and spherical aberration during focusing.

[0056] The rear group GR may be configured to include two focusing lens groups that move while changing the mutual distance during focusing. In this way, by moving the two focusing lens groups with different amounts of movement from each other, it is possible to satisfactorily suppress the aberration variation accompanying the variation in the shooting distance. Further, by arranging two focusing lens groups in the rear group GR, it becomes easy to suppress the variation in the angle of view during focusing.

[0057] The rear group GR may be configured to include an aspherical lens. For example, it may be configured such that at least one aspherical lens that is an aspherical lens having a concave surface facing the image side in the paraxial region and having an inflection point on the image-side lens surface where the concavo-convex shape changes midway as going from the optical axis to the peripheral portion is arranged in the rear group GR. Here, the phrase "having a concave surface facing the image side in the paraxial region" means that the lens surface on the image side is concave in the paraxial region. Further, the inflection point is a point where the surface shape switches from a convex shape to a concave shape or from a concave shape to a convex shape, that is, a point where the sign of the radius of curvature changes. By having an inflection point on the lens surface, it is possible to determine the refractive power of the peripheral portion of the lens without depending on the refractive power of the paraxial region. By including the aspherical surface having the above-described shape in the rear group GR, it is possible to reduce the incident angle of the light beam emitted from the imaging lens to the image plane Sim. When an imaging element is arranged on the image plane Sim in the imaging device, it is possible to reduce the incident angle to this imaging element. As an example, in the example of FIG. 1, the lens L27 corresponds to the above-described aspherical lens.

[0058] When the rear group GR includes an aspherical lens, its shape is not limited to the above example. For example, it may be configured such that at least one lens that has a convex surface facing the image side in the paraxial region and has an inflection point on the image-side lens surface where the concavo-convex shape changes midway as going from the optical axis to the peripheral portion is arranged in the rear group GR. Here, the phrase "having a convex surface facing the image side in the paraxial region" means that the lens surface on the image side is convex in the paraxial region. With such a configuration, it is advantageous for favorably correcting the field curvature and the distortion aberration while suppressing an increase in the overall optical length.

[0059] Further, at least one lens having a concave surface facing the object side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is arranged in the rear group GR. Here, "having a concave surface facing the object side in the paraxial region" means that the lens surface on the object side is concave in the paraxial region. Such a configuration is advantageous for favorably correcting field curvature and distortion aberration while ensuring back focus.

[0060] Alternatively, at least one lens having a convex surface facing the object side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is arranged in the rear group GR. Here, "having a convex surface facing the object side in the paraxial region" means that the lens surface on the object side is convex in the paraxial region. Such a configuration is advantageous for correcting astigmatism without deteriorating spherical aberration.

[0061] At least one of the aspherical lenses included in the imaging lens may be a composite aspherical lens in which a resin with an aspherical air contact surface is formed on the spherical surface of a glass lens. In this case, since an aspherical surface can be added to the lens surface while suppressing the manufacturing cost, it is possible to achieve both cost reduction and good correction of various aberrations. In this specification, the composite aspherical lens is not regarded as a cemented lens and is treated as a single lens, that is, a single lens that is not cemented.

[0062] The imaging lens preferably includes a cemented lens. The cemented lens included in the imaging lens of FIG. 1 is a two-piece cemented lens, but the imaging lens of the present disclosure may be configured to include a three-piece cemented lens. The three-piece cemented lens may be a cemented lens in which a first positive lens, a second positive lens, and a negative lens are cemented in this order. In that case, the first positive lens, the second positive lens, and the negative lens may be cemented in order from the object side to the image side, or the first positive lens, the second positive lens, and the negative lens may be cemented in order from the image side to the object side. Such a three-piece cemented lens is advantageous for suppressing longitudinal chromatic aberration.

[0063] When the imaging lens includes a three-lens cemented lens in which a first positive lens, a second positive lens, and a negative lens are cemented in this order, the surface of the second positive lens on the first positive lens side may be configured to face the concave surface toward the first positive lens side. In this case, it is advantageous for suppressing chromatic aberration of magnification.

[0064] The preferred configuration of the imaging lens of the present disclosure regarding the conditional expressions will be described below. In the description of the following conditional expressions, in order to avoid redundancy, the same symbols are used for those with the same definitions, and the duplicate description of the symbols is omitted. Also, hereinafter, in order to avoid redundancy, the "imaging lens of the present disclosure" is also simply referred to as the "imaging lens".

[0065] The imaging lens preferably satisfies the following conditional expression (1). Here, in the state of focusing on an infinite object, the sum of the distance on the optical axis from the most object-side lens surface of the front group GF to the most image-side lens surface of the rear group GR and the back focus at the air-equivalent distance of the entire system is defined as TL. The focal length of the entire system in the state of focusing on an infinite object is defined as f. Tan is the tangent. The maximum semi-field angle in the state of focusing on an infinite object is defined as ωm. TL is the overall length in the state of focusing on an infinite object. As an example, FIG. 3 shows the overall length TL described above, and FIG. 2 shows the maximum semi-field angle ωm described above. FIG. 3 is a diagram showing symbols and the like used in the conditional expressions in the cross-sectional view of the imaging lens of FIG. 1. By preventing the corresponding value of the conditional expression (1) from falling below the lower limit value, it is advantageous for maintaining good optical performance. By preventing the corresponding value of the conditional expression (1) from exceeding the upper limit value, it is advantageous for miniaturizing the lens system. 2.3 < TL / (f × tan ωm) < 7 (1)

[0066] In order to obtain better characteristics, the lower limit value of conditional expression (1) is more preferably 2.7, even more preferably 3.1, still more preferably 3.5, yet more preferably 3.9, and even more preferably 4.4. In order to obtain better characteristics, the upper limit value of conditional expression (1) is more preferably 6.5, even more preferably 6, still more preferably 5.6, yet more preferably 5.3, and even more preferably 5.2. For example, it is more preferable that the imaging lens satisfies the following conditional expression (1-1), and even more preferably satisfies the following conditional expression (1-2). Yes. 3.5 < TL / (f × tan ωm) < 5.6 (1-1) 4.4 < TL / (f × tan ωm) < 5.2 (1-2)

[0067] When the open F-number in the state of focusing on an infinite object is Fno, it is preferable that the imaging lens satisfies the following conditional expression (2). By preventing the corresponding value of conditional expression (2) from falling below the lower limit value, it is advantageous for suppressing the increase in the number of lens elements and the enlargement of the lens system while obtaining good optical performance. By preventing the corresponding value of conditional expression (2) from exceeding the upper limit value, it becomes easy to reduce the open F-number while widening the angle of view. 1.15 < Fno / tan ωm < 3.5 (2)

[0068] In order to obtain better characteristics, the lower limit value of conditional expression (2) is more preferably 1.2, even more preferably 1.25, still more preferably 1.3, yet more preferably 1.35, and even more preferably 1.5. In order to obtain better characteristics, the upper limit value of conditional expression (2) is more preferably 3.2, even more preferably 2.9, still more preferably 2.7, yet more preferably 2.5, and even more preferably 2.3. For example, it is more preferable that the imaging lens satisfies the following conditional expression (2-1). 1.3 < Fno / tan ωm < 2.7 (2-1)

[0069] The imaging lens preferably satisfies the following conditional expression (3). Here, the back focus at the air equivalent distance of the entire system in the state of focusing on an infinite object is denoted as Bf. The back focus Bf at the air equivalent distance of the entire system is the air equivalent distance on the optical axis from the lens surface closest to the image side of the imaging lens to the image plane Sim. As an example, the above back focus Bf is shown in FIG. 3. By preventing the corresponding value of the conditional expression (3) from falling below the lower limit value, an increase in the diameter of the lens closest to the image side of the imaging lens can be suppressed. By preventing the corresponding value of the conditional expression (3) from exceeding the upper limit value, an increase in the overall optical length can be suppressed. 0.3 < Bf / (f × tanωm) < 1.5 (3)

[0070] In order to obtain better characteristics, the lower limit value of the conditional expression (3) is more preferably 0.35, still more preferably 0.4, still more preferably 0.43, and still more preferably 0.45. In order to obtain better characteristics, the upper limit value of the conditional expression (3) is more preferably 1.3, still more preferably 1.2, still more preferably 1.1, and still more preferably 1.

[0071] The imaging lens preferably satisfies the following conditional expression (4). Here, the distance on the optical axis from the lens surface closest to the object side of the front group GF to the aperture stop St in the state of focusing on an infinite object is denoted as dFSt. As an example, the above distance dFSt is shown in FIG. 3. By preventing the corresponding value of the conditional expression (4) from falling below the lower limit value, a sufficient space on the object side of the aperture stop St can be ensured, so that an appropriate number of lenses can be arranged without unreasonably reducing the absolute value of the radius of curvature of the lens. This makes it easy to preferably correct various aberrations. By preventing the corresponding value of the conditional expression (4) from exceeding the upper limit value, it is possible to prevent the position of the aperture stop St from approaching the image plane Sim too much, and thus prevent the incident angle of the chief ray off the axis incident on the imaging element arranged on the image plane Sim in the imaging device from becoming excessive. 0.43 < dFSt / TL < 0.75 (4)

[0072] In order to obtain better characteristics, the lower limit value of conditional expression (4) is more preferably 0.45, still more preferably 0.47, still more preferably 0.49, still more preferably 0.51, still more preferably 0.53, and still more preferably 0.55. In order to obtain better characteristics, the upper limit value of conditional expression (4) is more preferably 0.71, still more preferably 0.69, still more preferably 0.67, still more preferably 0.65, still more preferably 0.63, and still more preferably 0.61.

[0073] The imaging lens preferably satisfies the following conditional expression (5). Here, the focal length of the front group GF in the state of being focused on an infinite object is denoted as fF. The focal length of the rear group GR in the state of being focused on an infinite object is denoted as fR. Conditional expression (5) is a conditional expression for appropriately setting the ratio of the refractive power of the front group GF to the refractive power of the rear group GR. The front group GF can play the role of a wide converter that increases the angle of view while ensuring sufficient back focus in the entire system. By preventing the corresponding value of conditional expression (5) from falling below the lower limit value, various aberrations such as spherical aberration can be suppressed. By preventing the corresponding value of conditional expression (5) from exceeding the upper limit value, it is advantageous for achieving a wide angle of view. -2 < fR / fF < 4 (5)

[0074] In order to obtain better characteristics, the lower limit value of conditional expression (5) is more preferably -1.5, still more preferably -1, and still more preferably -0.7. In order to obtain better characteristics, the upper limit value of conditional expression (5) is more preferably 3.5, still more preferably 3, and still more preferably 2.5.

[0075] The imaging lens preferably satisfies the following conditional expression (6). By preventing the corresponding value of the conditional expression (6) from falling below the lower limit value, the negative refractive power of the front group GF does not become too strong, which is advantageous for shortening the overall optical length. By preventing the corresponding value of the conditional expression (6) from exceeding the upper limit value, the positive refractive power of the front group GF does not become too strong, which is advantageous for correcting distortion aberration and field curvature. -1 < f / fF < 2 (6)

[0076] To obtain better characteristics, the lower limit value of the conditional expression (6) is more preferably -0.8, still more preferably -0.6, and even more preferably -0.4. To obtain better characteristics, the upper limit value of the conditional expression (6) is more preferably 1.3, still more preferably 0.7, and even more preferably 0.18.

[0077] The imaging lens preferably satisfies the following conditional expression (7). By preventing the corresponding value of the conditional expression (7) from falling below the lower limit value, it is advantageous for maintaining good optical performance. By preventing the corresponding value of the conditional expression (7) from exceeding the upper limit value, it is advantageous for miniaturizing the lens system. 6 < (TL × Fno) / (f × tan ωm) < 11 (7)

[0078] To obtain better characteristics, the lower limit value of the conditional expression (7) is more preferably 6.1, still more preferably 6.2, even more preferably 6.3, and even more preferably 6.4. To obtain better characteristics, the upper limit value of the conditional expression (7) is more preferably 10.5, still more preferably 10, even more preferably 9.5, and even more preferably 9. For example, the imaging lens more preferably satisfies the following conditional expression (7-1). 6.3 < (TL × Fno) / (f × tan ωm) < 9.5 (7-1)

[0079] In a configuration where the rear group GR includes at least one aspherical lens, it is preferable that the imaging lens satisfies the following conditional expression (8). Here, among the aspherical lenses included in the rear group GR, the most image-side aspherical lens is defined as the most image-side aspherical lens. The paraxial curvature radius of the object-side surface of the most image-side aspherical lens is denoted as Rcf. The curvature radius at the position of the maximum effective diameter of the object-side surface of the most image-side aspherical lens is denoted as Ryf. The paraxial curvature radius of the image-side surface of the most image-side aspherical lens is denoted as Rcr. The curvature radius at the position of the maximum effective diameter of the image-side surface of the most image-side aspherical lens is denoted as Ryr. By ensuring that the corresponding value of the conditional expression (8) does not fall below the lower limit value, the refractive power on the peripheral side of the lens does not become too strong, which is advantageous for correcting field curvature and distortion aberration. By ensuring that the corresponding value of the conditional expression (8) does not exceed the upper limit value, the refractive power on the peripheral side of the lens does not become too weak, which is advantageous for suppressing spherical aberration. 0.2 < |(1 / Rcf - 1 / Rcr) / (1 / Ryf - 1 / Ryr)| < 4 (8)

[0080] To obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (8) is 0.25, even more preferably 0.3, even more preferably 0.35, and even more preferably 0.4. To obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (8) is 3, even more preferably 2, even more preferably 1.4, and even more preferably 0.9.

[0081] Here, the "position of the maximum effective diameter" in this specification will be described with reference to FIG. 4. FIG. 4 is an explanatory diagram. In FIG. 4, the left side is the object side and the right side is the image side. FIG. 4 shows an on-axis light beam Xa and an off-axis light beam Xb passing through the lens Lx. In the example of FIG. 4, the light ray Xb1, which is the upper light ray of the off-axis light beam Xb, is the light ray passing through the outermost side. The "outer side" mentioned here refers to the radially outer side centered on the optical axis Z, that is, the side away from the optical axis Z. In this specification, the position of the intersection of this outermost passing light ray and the lens surface is the position Px of the maximum effective diameter. Also, twice the distance from the position Px of the maximum effective diameter to the optical axis Z is the effective diameter ED of the object-side surface of the lens Lx. Note that in the example of FIG. 4, the upper light ray of the off-axis light beam Xb is the light ray passing through the outermost side, but which light ray becomes the outermost passing light ray varies depending on the lens system.

[0082] In a configuration where the imaging lens includes two focusing lens groups, it is preferable that the imaging lens satisfies the following conditional expression (9). Here, among the two focusing lens groups included in the imaging lens, the focal length of the object-side focusing lens group is denoted as ff1, and the focal length of the image-side focusing lens group is denoted as ff2. By preventing the corresponding value of the conditional expression (9) from falling below the lower limit value, the refractive power of the object-side focusing lens group does not become too strong, so it becomes easy to correct the aberration. By preventing the corresponding value of the conditional expression (9) from exceeding the upper limit value, the refractive power of the object-side focusing lens group does not become too weak, so it becomes easy to correct the field curvature. 0.2 < |ff1 / ff2| < 5 (9)

[0083] In order to obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (9) is 0.25, even more preferably 0.3, even more preferably 0.35, and even more preferably 0.4. In order to obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (9) is 4, even more preferably 3, even more preferably 2.5, and even more preferably 2.

[0084] The imaging lens preferably satisfies the following conditional expression (10). Here, the combined focal length of all the lenses on the image side with respect to the most image-side focusing lens group among the focusing lens groups included in the imaging lens is defined as ffR. By ensuring that the corresponding value of the conditional expression (10) does not fall below the lower limit value, the negative combined refractive power of all the lenses on the image side with respect to the most image-side focusing lens group described above does not become too strong, which is advantageous for correcting chromatic aberration of magnification. By ensuring that the corresponding value of the conditional expression (10) does not exceed the upper limit value, the positive combined refractive power of all the lenses on the image side with respect to the most image-side focusing lens group described above does not become too strong, which is advantageous for correcting distortion aberration and field curvature. -1.5 < f / ffR < 1.5 (10)

[0085] To obtain better characteristics, the lower limit value of the conditional expression (10) is more preferably -1, still more preferably -0.7, still more preferably -0.5, still more preferably -0.3, and still more preferably -0.2. To obtain better characteristics, the upper limit value of the conditional expression (10) is more preferably 1, still more preferably 0.7, still more preferably 0.5, still more preferably 0.3, and still more preferably 0.2.

[0086] The imaging lens preferably satisfies the following conditional expression (11). Here, the paraxial curvature radius of the object-side surface of the most object-side lens of the front group GF is defined as RL1f. The paraxial curvature radius of the image-side surface of the most object-side lens of the front group GF is defined as RL1r. The conditional expression (11) defines the shape factor of the lens. By ensuring that the corresponding value of the conditional expression (11) does not fall below the lower limit value, it becomes easier to correct spherical aberration favorably. By ensuring that the corresponding value of the conditional expression (11) does not exceed the upper limit value, it becomes easier to correct coma aberration favorably. Also, by ensuring that the corresponding value of the conditional expression (11) does not exceed the upper limit value, the refractive power of the most object-side lens of the front group GF does not become too weak, which makes it easier to achieve wide-angleization. -3 < (RL1r - RL1f) / (RL1r + RL1f) < 0 (11)

[0087] In order to obtain better characteristics, the lower limit value of conditional expression (11) is more preferably -2, still more preferably -1, still more preferably -0.7, and still more preferably -0.5. In order to obtain better characteristics, the upper limit value of conditional expression (11) is more preferably -0.05, still more preferably -0.1, still more preferably -0.11, and still more preferably -0.12.

[0088] The imaging lens preferably satisfies the following conditional expression (12). By preventing the corresponding value of conditional expression (12) from falling below the lower limit value, correction of various aberrations and shortening of the overall optical length become easier. By preventing the corresponding value of conditional expression (12) from exceeding the upper limit value, the brightness of the lens system can be ensured. 0.9 < Fno < 2.1 (12)

[0089] In order to obtain better characteristics, the lower limit value of conditional expression (12) is more preferably 0.95, still more preferably 1, still more preferably 1.05, and still more preferably 1.1. In order to obtain better characteristics, the upper limit value of conditional expression (12) is more preferably 1.9, still more preferably 1.7, still more preferably 1.5, and still more preferably 1.3.

[0090] The imaging lens preferably satisfies the following conditional expression (13). The unit of ωm is degrees. By preventing the corresponding value of conditional expression (13) from falling below the lower limit value, a wide angle of view can be ensured, so that the imaging lens can have high added value. By preventing the corresponding value of conditional expression (13) from exceeding the upper limit value, it becomes easy to balance optical performance and miniaturization. 29 < ωm < 50 (13)

[0091] In order to obtain better characteristics, the lower limit value of conditional expression (13) is more preferably 29.5, still more preferably 30, still more preferably 30.5, still more preferably 31, and still more preferably 31.5. In order to obtain better characteristics, the upper limit value of conditional expression (13) is more preferably 47, still more preferably 44, still more preferably 41, still more preferably 38, and still more preferably 36.

[0092] In a configuration where a negative meniscus lens with a convex surface facing the object side is disposed on the most object side of the front group GF, the imaging lens preferably satisfies the following conditional expression (14). Here, the focal length of the negative meniscus lens disposed on the most object side of the front group GF and having a convex surface facing the object side is referred to as fL1m. By preventing the corresponding value of conditional expression (14) from falling below the lower limit value, the negative refractive power of the negative meniscus lens with respect to the refractive power of the entire system does not become too weak, which is advantageous for correcting various aberrations such as distortion aberration and field curvature. Regarding the upper limit of conditional expression (14), since the sign of the focal length of the negative meniscus lens is negative, fL1m / f < 0. -7 < fL1m / f < 0 (14)

[0093] In order to obtain better characteristics, the lower limit value of conditional expression (14) is more preferably -4, still more preferably -3.5, still more preferably -3, still more preferably -2.5, and still more preferably -2. In order to obtain better characteristics, the upper limit value of conditional expression (14) is preferably -0.4. By preventing the corresponding value of conditional expression (14) from becoming -0.4 or more, the negative refractive power of the negative meniscus lens with respect to the refractive power of the entire system does not become too strong, which is advantageous for favorably correcting the longitudinal chromatic aberration by the negative meniscus lens. In order to obtain better characteristics, the upper limit value of conditional expression (14) is more preferably -0.6, still more preferably -0.8, still more preferably -0.9, and still more preferably -1.

[0094] In a configuration where a negative meniscus lens with a convex surface facing the object side is arranged on the object side of the front group GF, it is preferable that the imaging lens satisfies the following conditional expression (15). Here, the Abbe number based on the d-line of the negative meniscus lens arranged on the object side of the front group GF and having a convex surface facing the object side is denoted as νdL1m. By ensuring that the corresponding value of the conditional expression (15) does not fall below the lower limit value, the Abbe number of the negative meniscus lens does not become too small, which is advantageous for correcting the magnification chromatic aberration well. By ensuring that the corresponding value of the conditional expression (15) does not exceed the upper limit value, the Abbe number of the negative meniscus lens does not become too large, so the refractive index does not become too low, and the refractive power of the negative meniscus lens does not become too weak, which is advantageous for correcting the distortion aberration and the field curvature well. 35 < νdL1m < 90 (15)

[0095] To obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (15) is 40, even more preferably 42, even more preferably 44, even more preferably 46, even more preferably 48, and even more preferably 50. To obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (15) is 85, even more preferably 80, even more preferably 75, even more preferably 70, even more preferably 65, and even more preferably 62.

[0096] The imaging lens preferably satisfies the following conditional expression (16). Here, the combined focal length of all the lenses on the object side of the most object-side focusing lens group among the focusing lens groups included in the imaging lens is defined as ffF. By preventing the corresponding value of the conditional expression (16) from falling below the lower limit value, the negative combined refractive power of all the lenses on the object side of the most object-side focusing lens group does not become too strong, so that an increase in the overall optical length can be suppressed, and it is advantageous for ensuring the peripheral light quantity. By preventing the corresponding value of the conditional expression (16) from exceeding the upper limit value, the positive combined refractive power of all the lenses on the object side of the most object-side focusing lens group does not become too strong, so that it is advantageous for correcting distortion aberration and field curvature. -2 < f / ffF < 1.5 (16)

[0097] To obtain better characteristics, the lower limit value of the conditional expression (16) is more preferably -1.5, still more preferably -1.2, still more preferably -0.9, still more preferably -0.7, and still more preferably -0.5. To obtain better characteristics, the upper limit value of the conditional expression (16) is more preferably 1.2, still more preferably 0.9, still more preferably 0.7, still more preferably 0.5, and still more preferably 0.3.

[0098] The imaging lens preferably satisfies the following conditional expression (17). Here, among the unbonded positive lenses included in the rear group GR, the focal length of the positive lens with the strongest refractive power is defined as fRp. By preventing the corresponding value of the conditional expression (17) from falling below the lower limit value, the refractive power of the positive lens in the rear group GR does not become too weak, so that it is advantageous for shortening the flange back and miniaturizing. By preventing the corresponding value of the conditional expression (17) from exceeding the upper limit value, the refractive power of the positive lens in the rear group GR does not become too strong, so that it is advantageous for correcting various aberrations such as spherical aberration. 0.4 < f / fRp < 1.3 (17)

[0099] In order to obtain better characteristics, the lower limit value of conditional expression (17) is more preferably 0.45, still more preferably 0.5, still more preferably 0.53, and still more preferably 0.55. In order to obtain better characteristics, the upper limit value of conditional expression (17) is more preferably 1.1, still more preferably 1, still more preferably 0.9, and still more preferably 0.8.

[0100] The imaging lens preferably satisfies the following conditional expression (18). Here, among the unbonded positive lenses included in the rear group GR, the Abbe number based on the d-line of the positive lens with the strongest refractive power is defined as νdRp. By ensuring that the corresponding value of conditional expression (18) does not fall below the lower limit value, the Abbe number of the positive lens with the strongest refractive power among the unbonded positive lenses included in the rear group GR will not become too small, which is advantageous for correcting chromatic aberration of magnification well. By ensuring that the corresponding value of conditional expression (18) does not exceed the upper limit value, the Abbe number of the positive lens with the strongest refractive power among the unbonded positive lenses included in the rear group GR will not become too large. As a result, the refractive index will not decrease too much, and the refractive power of this positive lens will not become too weak, which is advantageous for correcting distortion aberration and field curvature well. 25 < νdRp < 90 (18)

[0101] In order to obtain better characteristics, the lower limit value of conditional expression (18) is more preferably 40, still more preferably 50, still more preferably 55, and still more preferably 60. In order to obtain better characteristics, the upper limit value of conditional expression (18) is more preferably 85, still more preferably 80, still more preferably 75, and still more preferably 70.

[0102] When a lens having an inflection point where the concavo-convex shape changes midway from the optical axis to the peripheral part is defined as a specific aspherical lens, in a configuration where at least one specific aspherical lens is arranged in the rear group GR, it is preferable that the imaging lens satisfies the following conditional expression (19). Here, in the state of focusing on an infinite object, the sum of the distance on the optical axis from the image-side surface of the most image-side specific aspherical lens among the specific aspherical lenses included in the rear group GR to the most image-side lens surface of the rear group GR and the back focus Bf at the air-equivalent distance of the entire system is defined as dAsI. As an example, FIG. 3 shows the above distance dAsI. By preventing the corresponding value of the conditional expression (19) from falling below the lower limit value, it becomes easy to prevent interference between the imaging lens and various optical filters installed near the image plane. By preventing the corresponding value of the conditional expression (19) from exceeding the upper limit value, it becomes easy to correct distortion aberration and field curvature. 0.04 < dAsI / TL < 0.4 (19)

[0103] In order to obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (19) is 0.08, still more preferably 0.1, still more preferably 0.11, and still more preferably 0.12. In order to obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (19) is 0.35, still more preferably 0.3, still more preferably 0.25, and still more preferably 0.2.

[0104] In a configuration where the imaging lens includes a three-piece cemented lens in which a first positive lens, a second positive lens, and a negative lens are cemented in this order, it is preferable that the imaging lens satisfies the following conditional expression (20). Here, the refractive index of the second positive lens with respect to the d-line is defined as Ndp2. The Abbe number of the second positive lens based on the d-line is defined as νdp2. By preventing the corresponding value of the conditional expression (20) from falling below the lower limit value, materials other than those with a low refractive index and a low Abbe number can be selected, so it becomes easy to correct magnification chromatic aberration. By preventing the corresponding value of the conditional expression (20) from exceeding the upper limit value, materials other than those with a high refractive index and a high Abbe number can be selected, so a material with a small specific gravity can be selected, and weight reduction becomes easy. 1.7 < Ndp2 + 0.01 × νdp2 < 2.05 (20)

[0105] In order to obtain better characteristics, the lower limit value of the conditional expression (20) is more preferably 1.74, still more preferably 1.76, still more preferably 1.77, and still more preferably 1.78. In order to obtain better characteristics, the upper limit value of the conditional expression (20) is more preferably 2.02, still more preferably 2, still more preferably 1.99, and still more preferably 1.98.

[0106] The above-described preferred configurations and possible configurations can be arbitrarily combined within a non-conflicting range, and it is preferable to selectively adopt them as appropriate according to the required specifications.

[0107] As an example, a preferred embodiment of the imaging lens of the present disclosure includes, in order from the object side to the image side, a front group GF, an aperture stop St, and a rear group GR. The rear group GR includes one or two focusing lens groups that move along the optical axis Z during focusing. During focusing, the distance on the optical axis from the most object-side lens surface of the front group GF to the image plane Sim is invariant, and satisfies the above conditional expressions (1), (2), and (3).

[0108] Next, examples of the imaging lens of the present disclosure will be described with reference to the drawings. Note that the group of cross-sectional views of each example and the reference signs attached to the lenses are used independently for each example in order to avoid complication of the description and the drawings due to an increase in the number of digits of the reference signs. Therefore, even if the same reference sign is attached in the drawings of different examples, it is not necessarily a common configuration.

[0109] [Example 1] The cross-sectional view of the configuration of the imaging lens according to Embodiment 1 is shown in FIG. 1. Since the illustration method and configuration are as described above, redundant explanations are partially omitted here. The imaging lens according to Embodiment 1 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The imaging lens includes only one focusing lens group. When focusing from an infinite object to a close-distance object, the focusing lens group moves toward the object side.

[0110] For the imaging lens according to Embodiment 1, the basic lens data is shown in Table 1, the specifications and variable surface intervals are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0111] The table of the basic lens data is described as follows. In the column of "Sn", the surface numbers are shown when the surface closest to the object side is defined as the first surface and the numbers are incremented one by one toward the image side. In the column of "R", the radius of curvature of each surface is shown. In the column of "D", the axial surface interval between each surface and the surface adjacent to it on the image side is shown. In the column of "Nd", the refractive index with respect to the d-line of each lens is shown. In the column of "νd", the Abbe number based on the d-line of each lens is shown.

[0112] Including the tables of the embodiments described later, the column of "Material" in the table of the basic lens data is described as follows. For lenses made of resin, "Plastic" is described in the column of "Material". For lenses made of materials other than resin, the material name and the name of its manufacturing company are shown with a period in between. In the table, the manufacturing company names are shown schematically as follows. "OHARA" indicates Ohara Corporation. "CDGM" indicates Chengdu Guangming Optoelectronic Co., Ltd. "HOYA" indicates HOYA Corporation. "NHG" indicates Hubei Xinhua Optoelectronic Information Materials Co., Ltd. In the column of "ED", the effective diameter of each surface is shown. Note that in the column of "ED", the description of some surfaces not related to the conditional expression is omitted.

[0113] In the table of basic lens data, the sign of the radius of curvature of the surface facing the object side with a convex shape is positive, and the sign of the radius of curvature of the surface facing the image side with a convex shape is negative. In the column of the surface number corresponding to the aperture stop St, the surface number and the phrase "(St)" are entered. The value in the bottommost column of the D column in the table is the distance between the most image-side surface in the table and the image plane Sim. Regarding the variable surface interval during focusing, the symbol DD[] is used, and the surface number on the object side of this interval is attached in [] and entered in the column of the surface interval.

[0114] Table 2 shows the focal length, back focus, open F-number, maximum full angle of view, and variable surface interval of the entire system based on the d-line standard. The [°] in the column of the maximum full angle of view indicates that the unit is degrees. In Table 2, the "Infinity" column shows each value in the state of focusing on an infinite object, and the "Close distance" column shows each value in the state of focusing on the closest object. However, the focal length shows only the value in the state of focusing on an infinite object. In the "Close distance" column, the absolute value of the shooting magnification in the state of focusing on the closest object is shown with "times" attached.

[0115] In the basic lens data, an asterisk is attached to the surface number of the aspherical surface, and the numerical value of the paraxial radius of curvature is described in the column of the radius of curvature of the aspherical surface. In Table 3, the Sn row shows the surface number of the aspherical surface, and the KA and Am rows show the numerical values of the aspherical coefficients for each aspherical surface. Note that m in Am is an integer of 3 or more and varies depending on the surface. For example, in the first surface of Example 1, m = 4, 6, 8, 10, 12. The "E±n" (n: integer) of the numerical value of the aspherical coefficient in Table 3 means "×10 ±n ". KA and Am are the aspherical coefficients in the aspherical formula represented by the following formula. Zd = C×h 2 / {1+(1 - KA×C 2 ×h 2 ) 1 / 2}+ΣAm×h m However, Zd: Aspherical depth (the length of the perpendicular line dropped from the point on the aspherical surface with height h to the plane perpendicular to the optical axis Z where the aspherical vertex touches) h: Height (the distance from the optical axis Z to the lens surface) C: Reciprocal of the paraxial radius of curvature KA, Am: Aspherical coefficient where Σ of the aspherical formula means the sum with respect to m.

[0116] In the data of each table, degrees are used as the unit of angle and mm (millimeter) is used as the unit of length. However, since the optical system can be used even with proportional enlargement or reduction, other appropriate units can also be used. Also, in each of the tables shown below, the numerical values are rounded to a predetermined number of digits.

[0117]

Table 1

[0118]

Table 2

[0119]

Table 3

[0120] Fig. 5 shows the aberration diagrams of the imaging lens of Example 1. In Fig. 5, from left to right, spherical aberration, astigmatism, distortion, and lateral chromatic aberration are shown. In Fig. 5, the upper row marked with "infinity" shows the aberration diagrams in the state of focusing on an infinite object, and the lower row marked with "near distance" shows the aberration diagrams in the state of focusing on the closest object. In the spherical aberration diagram, the aberrations at the d-line, C-line, and F-line are shown by solid line, long dashed line, and short dashed line, respectively. In the astigmatism diagram, the aberration in the sagittal direction of the d-line is shown by a solid line, and the aberration in the tangential direction of the d-line is shown by a short dashed line. In the distortion diagram, the aberration at the d-line is shown by a solid line. In the lateral chromatic aberration diagram, the aberrations at the C-line and F-line are shown by a long dashed line and a short dashed line, respectively. In the spherical aberration diagram, the value of the open F-number is shown after "FNo.=". In the other aberration diagrams, the value of the maximum semi-aperture angle is shown after "ω=".

[0121] The symbols, meanings, description methods, and illustration methods of the respective data related to the above-mentioned Example 1 are basically the same in the following examples unless otherwise specified. Therefore, duplicate explanations are omitted below.

[0122] [Example 2] A cross-sectional view of the configuration of the imaging lens of Example 2 is shown in FIG. 6. The imaging lens of Example 2 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of five lenses L11 to L15 in order from the object side to the image side. The rear group GR consists of eight lenses L21 to L28 in order from the object side to the image side. The imaging lens includes only one focusing lens group. The focusing lens group consists of the aperture stop St and lenses L21 to L27. When focusing from an infinite object to a close-distance object, the focusing lens group moves toward the object side.

[0123] Regarding the imaging lens of Example 2, the basic lens data is shown in Table 4, the specifications and variable surface intervals are shown in Table 5, the aspherical coefficients are shown in Table 6, and each aberration diagram is shown in FIG. 7.

[0124]

Table 4

[0125]

Table 5

[0126]

Table 6

[0127] [Example 3] A cross-sectional view of the configuration of the imaging lens according to Embodiment 3 is shown in FIG. 8. The imaging lens according to Embodiment 3 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of eight lenses L11 to L18 in order from the object side to the image side. The rear group GR consists of six lenses L21 to L26 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L16, and the focusing lens group on the image side consists of lenses L21 to L24. When focusing from an infinite object to a close-distance object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0128] Regarding the imaging lens according to Embodiment 3, the basic lens data is shown in Table 7, the specifications and variable surface intervals are shown in Table 8, the aspherical coefficients are shown in Table 9, and each aberration diagram is shown in FIG. 9.

[0129]

Table 7

[0130]

Table 8

[0131]

Table 9

[0132] [Embodiment 4] A cross-sectional view of the configuration of the imaging lens according to Example 4 is shown in FIG. 10. The imaging lens according to Example 4 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF includes nine lenses L11 to L19 in order from the object side to the image side. The rear group GR includes six lenses L21 to L26 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L16, and the focusing lens group on the image side consists of lenses L21 to L24. When focusing from an infinite object to a close-distance object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0133] Regarding the imaging lens according to Example 4, the basic lens data is shown in Table 10, the specifications and variable surface intervals are shown in Table 11, the aspherical coefficients are shown in Table 12, and each aberration diagram is shown in FIG. 11.

[0134]

Table 10

[0135]

Table 11

[0136]

Table 12

[0137] [Example 5] A cross-sectional view of the configuration of the imaging lens according to Example 5 is shown in FIG. 12. The imaging lens according to Example 5 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of eight lenses L11 to L18 in order from the object side to the image side. The rear group GR consists of seven lenses L21 to L27 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L16, and the focusing lens group on the image side consists of lenses L21 to L25. When focusing from an infinite object to a close object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0138] Regarding the imaging lens according to Example 5, the basic lens data is shown in Table 13, the specifications and variable surface intervals are shown in Table 14, the aspherical coefficients are shown in Table 15, and each aberration diagram is shown in FIG. 13.

[0139]

Table 13

[0140]

Table 14

[0141]

Table 15

[0142] [Example 6] A cross-sectional view of the configuration of the imaging lens of Example 6 is shown in FIG. 14. The imaging lens of Example 6 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of five lenses L11 to L15 in order from the object side to the image side. The rear group GR consists of eight lenses L21 to L28 in order from the object side to the image side. The imaging lens includes only one focusing lens group. The focusing lens group consists of lenses L21 to L26. When focusing from an infinite object to a close-distance object, the focusing lens group moves toward the object side.

[0143] Regarding the imaging lens of Example 6, the basic lens data is shown in Table 16, the specifications and variable surface intervals are shown in Table 17, the aspherical coefficients are shown in Table 18, and each aberration diagram is shown in FIG. 15.

[0144] [Table 16]

[0145] [Table 17]

[0146] [Table 18]

[0147] [Example 7] A cross-sectional view of the configuration of the imaging lens according to Example 7 is shown in FIG. 16. The imaging lens according to Example 7 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of five lenses L11 to L15 in order from the object side to the image side. The rear group GR consists of eight lenses L21 to L28 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Of the two focusing lens groups, the focusing lens group on the object side consists of lenses L14 to L15, and the focusing lens group on the image side consists of lenses L21 to L27. When focusing from an infinite object to a close object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0148] Regarding the imaging lens according to Example 7, the basic lens data is shown in Table 19, the specifications and variable surface intervals are shown in Table 20, the aspherical coefficients are shown in Table 21, and each aberration diagram is shown in FIG. 17.

[0149]

Table 19

[0150]

Table 20

[0151]

Table 21

[0152] [Example 8] A cross-sectional view of the configuration of the imaging lens according to Example 8 is shown in FIG. 18. The imaging lens according to Example 8 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of four lenses L11 to L14 in order from the object side to the image side. The rear group GR consists of eight lenses L21 to L28 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lenses L13 to L14, and the focusing lens group on the image side consists of lenses L21 to L27. When focusing from an infinite object to a close object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0153] Regarding the imaging lens of Example 8, the basic lens data is shown in Table 22, the specifications and variable surface intervals are shown in Table 23, the aspherical coefficients are shown in Table 24, and each aberration diagram is shown in FIG. 19.

[0154] [Table 22]

[0155] [Table 23]

[0156] [Table 24]

[0157] [Example 9] A cross-sectional view of the configuration of the imaging lens according to Example 9 is shown in FIG. 20. The imaging lens according to Example 9 includes, in order from the object side to the image side, a front group GF having a negative refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF includes five lenses L11 to L15 in order from the object side to the image side. The lens L11 is a composite aspherical lens in which a resin L11b having an aspherical air contact surface is formed on the spherical surface of a glass lens L11a. The rear group GR includes nine lenses L21 to L29 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of the lens L15, and the focusing lens group on the image side consists of the lens L28. When focusing from an infinite object to a close object, the focusing lens group on the object side moves toward the image side, and the focusing lens group on the image side moves toward the object side.

[0158] For the imaging lens according to Example 9, the basic lens data is shown in Table 25, the specifications and variable surface intervals are shown in Table 26, the aspherical coefficients are shown in Tables 27A and 27B, and each aberration diagram is shown in FIG. 21.

[0159] [Table 25]

[0160] [Table 26]

[0161] [Table 27A]

[0162] [Table 27B]

[0163] [Example 10] A cross-sectional view of the configuration of the imaging lens according to Embodiment 10 is shown in FIG. 22. The imaging lens according to Embodiment 10 includes, in order from the object side to the image side, a front group GF having a negative refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of four lenses L11 to L14 in order from the object side to the image side. The rear group GR consists of eleven lenses L21 to L31 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of the lens L14, and the focusing lens group on the image side consists of the lens L29. When focusing from an infinite object to a close-distance object, the focusing lens group on the object side moves toward the image side, and the focusing lens group on the image side moves toward the object side.

[0164] Regarding the imaging lens according to Embodiment 10, the basic lens data is shown in Table 28, the specifications and variable surface intervals are shown in Table 29, the aspherical coefficients are shown in Tables 30A and 30B, and each aberration diagram is shown in FIG. 23.

[0165]

Table 28

[0166]

Table 29

[0167]

Table 30A

[0168]

Table 30B

[0169] [Embodiment 11] A cross-sectional view of the configuration of the imaging lens of Example 11 is shown in FIG. 24. The imaging lens of Example 11 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of six lenses L11 to L16 in order from the object side to the image side. The rear group GR consists of six lenses L21 to L26 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L16, and the focusing lens group on the image side consists of lenses L23 to L24. When focusing from an infinite object to a close object, the focusing lens group on the object side and the focusing lens group on the image side move toward the image side while changing the mutual distance therebetween.

[0170] Regarding the imaging lens of Example 11, the basic lens data is shown in Table 31, the specifications and variable surface intervals are shown in Table 32, the aspherical coefficients are shown in Table 33, and each aberration diagram is shown in FIG. 25.

[0171]

Table 31

[0172]

Table 32

[0173]

Table 33

[0174] [Example 12] A cross-sectional view of the configuration of the imaging lens according to Embodiment 12 is shown in FIG. 26. The imaging lens according to Embodiment 12 includes, in order from the object side to the image side, a front group GF having a negative refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of five lenses L11 to L15 in order from the object side to the image side. The rear group GR consists of six lenses L21 to L26 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Of the two focusing lens groups, the focusing lens group on the object side consists of lens L15, and the focusing lens group on the image side consists of lenses L23 to L24. When focusing from an infinite object to a close-distance object, the focusing lens group on the object side and the focusing lens group on the image side move toward the image side while changing the mutual distance therebetween.

[0175] Regarding the imaging lens according to Embodiment 12, the basic lens data is shown in Table 34, the specifications and variable surface intervals are shown in Table 35, the aspherical coefficients are shown in Table 36, and each aberration diagram is shown in FIG. 27.

[0176]

Table 34

[0177]

Table 35

[0178]

Table 36

[0179] [Embodiment 13] A cross-sectional view of the configuration of the imaging lens of Example 13 is shown in FIG. 28. The imaging lens of Example 13 is composed of a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power, in order from the object side to the image side. The front group GF is composed of six lenses L11 to L16, in order from the object side to the image side. The rear group GR is composed of nine lenses L21 to L29, in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L21, and the focusing lens group on the image side consists of lens L26. When focusing from an infinite object to a close object, the focusing lens group on the object side moves toward the object side, and the focusing lens group on the image side moves toward the image side.

[0180] Regarding the imaging lens of Example 13, the basic lens data is shown in Table 37, the specifications and variable surface intervals are shown in Table 38, the aspherical coefficients are shown in Table 39, and each aberration diagram is shown in FIG. 29.

[0181]

Table 37

[0182]

Table 38

[0183]

Table 39

[0184] [Example 14] A cross-sectional view of the configuration of the imaging lens according to Embodiment 14 is shown in FIG. 30. The imaging lens according to Embodiment 14 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a negative refractive power. The front group GF consists of seven lenses L11 to L17 in order from the object side to the image side. The rear group GR consists of four lenses L21 to L24 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Among the two focusing lens groups, the focusing lens group on the object side consists of lens L21, and the focusing lens group on the image side consists of lens L22. When focusing from an infinite object to a close object, the focusing lens group on the object side moves toward the image side, and the focusing lens group on the image side moves toward the object side.

[0185] Regarding the imaging lens according to Embodiment 14, the basic lens data is shown in Table 40, the specifications and variable surface intervals are shown in Table 41, the aspherical coefficients are shown in Table 42, and each aberration diagram is shown in FIG. 31.

[0186]

Table 40

[0187]

Table 41

[0188]

Table 42

[0189] [Embodiment 15] A cross-sectional view of the configuration of the imaging lens according to Embodiment 15 is shown in FIG. 32. The imaging lens according to Embodiment 15 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of 10 lenses L11 to L20 in order from the object side to the image side. The rear group GR consists of 6 lenses L21 to L26 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Of the two focusing lens groups, the focusing lens group on the object side consists of lenses L16 to L17, and the focusing lens group on the image side consists of lenses L21 to L24. When focusing from an infinite object to a close object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0190] Regarding the imaging lens according to Embodiment 15, the basic lens data is shown in Table 43, the specifications and variable surface intervals are shown in Table 44, the aspherical coefficients are shown in Table 45, and each aberration diagram is shown in FIG. 33.

[0191] [Table 43]

[0192] [Table 44]

[0193] [Table 45]

[0194] [Embodiment 16] A cross-sectional view of the configuration of the imaging lens according to Example 16 is shown in FIG. 34. The imaging lens according to Example 16 includes, in order from the object side to the image side, a front group GF having a positive refractive power, an aperture stop St, and a rear group GR having a positive refractive power. The front group GF consists of nine lenses L11 to L19 in order from the object side to the image side. The rear group GR consists of seven lenses L21 to L27 in order from the object side to the image side. The imaging lens includes only two focusing lens groups. Of the two focusing lens groups, the focusing lens group on the object side consists of lens L17, and the focusing lens group on the image side consists of lenses L21 to L25. When focusing from an infinite object to a close-distance object, the focusing lens group on the object side and the focusing lens group on the image side move toward the object side while changing the mutual distance therebetween.

[0195] Regarding the imaging lens according to Example 16, the basic lens data is shown in Table 46, the specifications and variable surface intervals are shown in Table 47, the aspherical coefficients are shown in Table 48, and each aberration diagram is shown in FIG. 35.

[0196]

Table 46

[0197]

Table 47

[0198]

Table 48

[0199] Tables 49 to 52 show the corresponding values of conditional expressions (1) to (20) of the imaging lenses according to Examples 1 to 16, as well as the values of Ryf and Ryr. The preferred ranges of the conditional expressions may be set using the corresponding values of the examples shown in Tables 49 to 52 as the upper or lower limits of the conditional expressions.

[0200]

Table 49

[0201]

Table 50

[0202]

Table 51

[0203]

Table 52

[0204] The imaging lenses of Examples 1 to 16 all have an F-number smaller than 1.9. In particular, the imaging lenses of some of the examples have an F-number smaller than 1.5. Also, the imaging lenses of Examples 1 to 16 all have a maximum half field angle of 30 degrees or more in a state of being focused on an infinite object and are configured to be wide-angle. In particular, the imaging lenses of some of the examples have the above maximum half field angle of 40 degrees or more. Further, the imaging lenses of Examples 1 to 16 are all configured to be small, and various aberrations are well corrected to maintain high optical performance.

[0205] Next, an imaging device according to an embodiment of the present disclosure will be described. FIGS. 36 and 37 show external views of a camera 30 which is an imaging device according to an embodiment of the present disclosure. FIG. 36 shows a perspective view of the camera 30 as seen from the front side, and FIG. 37 shows a perspective view of the camera 30 as seen from the back side. The camera 30 is a so-called mirrorless type digital camera, and an interchangeable lens 20 can be detachably attached thereto. The interchangeable lens 20 includes an imaging lens 1 according to an embodiment of the present disclosure housed in a lens barrel.

[0206] The camera 30 includes a camera body 31. A shutter button 32 and a power button 33 are provided on the upper surface of the camera body 31. Also, an operation unit 34, an operation unit 35, and a display unit 36 are provided on the back surface of the camera body 31. The display unit 36 can display an image that has been captured and an image within the angle of view before being captured.

[0207] At the center of the front surface of the camera body 31, a shooting aperture through which light from the shooting object enters is provided. A mount 37 is provided at a position corresponding to the shooting aperture, and an interchangeable lens 20 is attached to the camera body 31 via the mount 37.

[0208] An image sensor 38 is provided inside the camera body 31. The image sensor 38 outputs an imaging signal corresponding to the subject image formed by the interchangeable lens 20. As the image sensor 38, for example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like is used. Inside the camera body 31, a signal processing circuit (not shown), a recording medium (not shown), and the like are provided. The signal processing circuit processes the imaging signal output from the image sensor 38 to generate an image. The recording medium is for recording the generated image. In the camera 30, it is possible to shoot a still image or a moving image by pressing the shutter button 32, and the image data obtained by this shooting is recorded on the above recording medium.

[0209] As described above, the technology of the present disclosure has been described with reference to the embodiments and examples. However, the technology of the present disclosure is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, the distance between surfaces, the refractive index, the Abbe number, the aspherical coefficient, etc. of each lens are not limited to the values shown in the above examples, and other values can be taken.

[0210] Also, the imaging device according to the embodiment of the present disclosure is not limited to the above example. For example, it can be variously configured such as a camera other than the mirrorless type, a film camera, a video camera, and a security camera.

[0211] Regarding the above embodiments and examples, the following additional remarks are further disclosed. [Additional Remark 1] It consists of a front group, an aperture stop, and a rear group in order from the object side to the image side. The rear group includes one or two focusing lens groups that move along the optical axis during focusing. When focusing, the distance on the optical axis from the lens surface closest to the object of the front lens group to the image plane is invariant. When focused on an infinite object, let TL be the sum of the distance on the optical axis from the lens surface closest to the object of the front lens group to the lens surface closest to the image of the rear lens group and the back focus at the air equivalent distance of the entire system. Let f be the focal length of the entire system when focused on an infinite object. Let ωm be the maximum half field angle when focused on an infinite object. Let Fno be the aperture F-number when focused on an infinite object. When the back focus at the air equivalent distance of the entire system when focused on an infinite object is Bf, 2.3 < TL / (f × tanωm) < 7 (1) 1.15 < Fno / tanωm < 3.5 (2) 0.3 < Bf / (f × tanωm) < 1.5 (3) An imaging lens that satisfies the conditional expressions (1), (2), and (3) represented by the above. [Appendix 2] 3.5 < TL / (f × tanωm) < 5.6 (1-1) The imaging lens according to Appendix 1 that satisfies the conditional expression (1-1) represented by the above. [Appendix 3] 4.4 < TL / (f × tanωm) < 5.2 (1-2) The imaging lens according to Appendix 1 that satisfies the conditional expression (1-2) represented by the above. [Appendix 4] 1.3 < Fno / tanωm < 2.7 (2-1) The imaging lens according to any one of Appendices 1 to 3 that satisfies the conditional expression (2-1) represented by the above. [Appendix 5] When the distance on the optical axis from the lens surface closest to the object of the front lens group to the aperture stop when focused on an infinite object is dFSt, 0.43 < dFSt / TL < 0.75 (4) The imaging lens according to any one of Appendices 1 to 4 that satisfies the conditional expression (4) represented by the above. [Appendix 6] Let the focal length of the front group in the state of focusing on an infinitely distant object be fF, when the focal length of the rear group in the state of focusing on an infinitely distant object is fR, -2 < fR / fF < 4 (5) The imaging lens according to any one of Appendices 1 to 5 that satisfies the conditional expression (5) represented by [Appendix 7] When the focal length of the front group in the state of focusing on an infinitely distant object is fF, -1 < f / fF < 2 (6) The imaging lens according to any one of Appendices 1 to 6 that satisfies the conditional expression (6) represented by [Appendix 8] 6 < (TL × Fno) / (f × tan ωm) < 11 (7) The imaging lens according to any one of Appendices 1 to 7 that satisfies the conditional expression (7) represented by [Appendix 9] 6.3 < (TL × Fno) / (f × tan ωm) < 9.5 (7-1) The imaging lens according to any one of Appendices 1 to 7 that satisfies the conditional expression (7-1) represented by [Appendix 10] The front group includes one focusing lens group that moves along the optical axis during focusing. The imaging lens according to any one of Appendices 1 to 9 [Appendix 11] The rear group includes two focusing lens groups that move while changing the mutual distance during focusing. The imaging lens according to any one of Appendices 1 to 10 [Appendix 12] At least one lens having a convex surface facing the object side in the paraxial region and having an inflection point on the object-side lens surface where the concavo-convex shape changes midway from the optical axis to the peripheral part is arranged in the rear group. The imaging lens according to any one of Appendices 1 to 11 [Appendix 13] At least one lens having a concave surface facing the object side in the paraxial region and having an inflection point on the object-side lens surface where the concavo-convex shape changes midway from the optical axis to the peripheral part is arranged in the rear group. The imaging lens according to any one of Appendices 1 to 12 [Appendix 14] At least one lens having a convex surface facing the image side in the paraxial region and having an inflection point on the image-side lens surface where the concavo-convex shape changes midway from the optical axis to the peripheral portion is arranged in the rear group, and the imaging lens according to any one of Appendices 1 to 13. [Appendix 15] At least one lens having a concave surface facing the image side in the paraxial region and having an inflection point on the image-side lens surface where the concavo-convex shape changes midway from the optical axis to the peripheral portion is arranged in the rear group, and the imaging lens according to any one of Appendices 1 to 14. [Appendix 16] The imaging lens according to any one of Appendices 1 to 15, including a three-piece cemented lens cemented in the order of a first positive lens, a second positive lens, and a negative lens. [Appendix 17] The imaging lens according to Appendix 16, wherein the surface of the second positive lens on the first positive lens side faces the first positive lens side with a concave surface. [Appendix 18] The rear group includes at least one aspherical lens, Among the aspherical lenses included in the rear group, the aspherical lens closest to the image side is defined as the most image-side aspherical lens, Let the paraxial radius of curvature of the object-side surface of the most image-side aspherical lens be Rcf, Let the radius of curvature at the position of the maximum effective diameter of the object-side surface of the most image-side aspherical lens be Ryf, Let the paraxial radius of curvature of the image-side surface of the most image-side aspherical lens be Rcr, When the radius of curvature at the position of the maximum effective diameter of the image-side surface of the most image-side aspherical lens is Ryr, 0.2 < |(1 / Rcf - 1 / Rcr) / (1 / Ryf - 1 / Ryr)| < 4 (8) The imaging lens according to any one of Appendices 1 to 17, satisfying the conditional expression (8) represented by the above. [Appendix 19] The number of focusing lens groups included in the imaging lens is two, Among the two focusing lens groups included in the imaging lens, let the focal length of the focusing lens group on the object side be ff1, When the focal length of the image-side focusing lens group among the two focusing lens groups included in the imaging lens is ff2, 0.2 < |ff1 / ff2| < 5 (9) The imaging lens according to any one of Appendices 1 to 18 that satisfies the conditional expression (9) represented by [Appendix 20] When the combined focal length of all the lenses on the image side of the most image-side focusing lens group among the focusing lens groups included in the imaging lens is ffR, -1.5 < f / ffR < 1.5 (10) The imaging lens according to any one of Appendices 1 to 19 that satisfies the conditional expression (10) represented by [Appendix 21] An imaging device including the imaging lens according to any one of Appendices 1 to 20.

Explanation of Signs

[0212] 1 Imaging lens 20 Interchangeable lens 30 Camera 31 Camera body 32 Shutter button 33 Power button 34 Operation unit 35 Operation unit 36 Display unit 37 Mount 38 Image sensor Bf Back focus dAsI Distance dFSt Distance ED Effective diameter GF Front group GR Rear group L11~L31 Lenses L11a Lens L11b Resin Lx Lens Px Position of the maximum effective diameter Sim Image plane St Aperture stop TL Overall length Xa On-axis light beam Xb Off-axis light beam Xb1 ray Z optical axis ωm maximum half angular aperture

Claims

1. It consists of a front group, an aperture stop, and a rear group in order from the object side to the image side. The rear group includes one or two focusing lens groups that move along the optical axis during focusing. During focusing, the distance on the optical axis from the most object-side lens surface of the front group to the image plane remains unchanged. Let TL be the sum of the distance on the optical axis from the most object-side lens surface of the front group to the most image-side lens surface of the rear group in the state of focusing on an infinite object and the back focus at the air-equivalent distance of the entire system. Let f be the focal length of the entire system in the state of focusing on an infinite object. Let ωm be the maximum half field angle in the state of focusing on an infinite object. Let Fno be the open F-number in the state of focusing on an infinite object. When the back focus at the air-equivalent distance of the entire system in the state of focusing on an infinite object is Bf. 2.3 < TL / (f × tanωm) < 7 (1) 1.15 < Fno / tanωm < 3.5 (2) 0.3 < Bf / (f × tanωm) < 1.5 (3) An imaging lens that satisfies the conditional expressions (1), (2), and (3) represented by the above.

2. When the distance on the optical axis from the most object-side lens surface of the front group to the aperture stop in the state of focusing on an infinite object is dFSt. 0.43 < dFSt / TL < 0.75 (4) The imaging lens according to Claim 1 that satisfies the conditional expression (4) represented by the above.

3. Let fF be the focal length of the front group in the state of focusing on an infinite object. When the focal length of the rear group in the state of focusing on an infinite object is fR. -2 < fR / fF < 4 (5) The imaging lens according to Claim 1 that satisfies the conditional expression (5) represented by the above.

4. When the focal length of the front group in the state of being focused on an infinitely distant object is fF, -1 < f / fF < 2 (6) The imaging lens according to claim 1, which satisfies the conditional expression (6) represented by

5. 6 < (TL × Fno) / (f × tan ωm) < 11 (7) The imaging lens according to claim 1, which satisfies the conditional expression (7) represented by

6. The imaging lens according to claim 1, wherein the front group includes one focusing lens group that moves along the optical axis during focusing.

7. The imaging lens according to claim 1, wherein the rear group includes two of the focusing lens groups that move while changing the mutual distance during focusing.

8. At least one lens having a bending point on the lens surface on the object side, which has a convex surface facing the object side in the paraxial region and the concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group. The imaging lens according to claim 1.

9. At least one lens having a bending point on the lens surface on the object side, which has a concave surface facing the object side in the paraxial region and the concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group. The imaging lens according to claim 1.

10. At least one lens having a bending point on the lens surface on the image side, which has a convex surface facing the image side in the paraxial region and the concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group. The imaging lens according to claim 1.

11. At least one lens having a bending point on the lens surface on the image side, which has a concave surface facing the image side in the paraxial region and the concavo-convex shape changes halfway from the optical axis to the peripheral part, is arranged in the rear group. The imaging lens according to claim 1.

12. The imaging lens according to claim 1, including a three-piece cemented lens cemented in the order of a first positive lens, a second positive lens, and a negative lens.

13. The imaging lens according to claim 12, wherein a surface of the second positive lens on the first positive lens side faces a concave surface toward the first positive lens side.

14. 3.5 < TL / (f × tanωm) < 5.6 (1-1) The imaging lens according to claim 1, which satisfies the conditional expression (1-1) represented by the above.

15. 1.3 < Fno / tanωm < 2.7 (2-1) The imaging lens according to claim 1, which satisfies the conditional expression (2-1) represented by the above.

16. 3.5 < TL / (f × tanωm) < 5.6 (1-1) The imaging lens according to claim 15, which satisfies the conditional expression (1-1) represented by the above.

17. 6 < (TL × Fno) / (f × tanωm) < 11 (7) The imaging lens according to claim 16, which satisfies the conditional expression (7) represented by the above.

18. The imaging lens according to claim 17, including a three-piece cemented lens cemented in the order of a first positive lens, a second positive lens, and a negative lens.

19. The imaging lens according to claim 18, wherein a surface of the second positive lens on the first positive lens side faces a concave surface toward the first positive lens side.

20. The imaging lens according to claim 17, wherein the front group includes one focusing lens group that moves along the optical axis during focusing.

21. At least one lens having a convex surface facing the object side in the paraxial region and having an inflection point on the lens surface on the object side where the concavo-convex shape changes midway from the optical axis to the peripheral portion is arranged in the rear group. The imaging lens according to claim 20.

22. The imaging lens according to claim 17, wherein the rear group includes two focusing lens groups that move while changing the mutual distance during focusing.

23. An imaging lens according to claim 22, wherein at least one lens having a convex surface facing the object side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is disposed in the rear group.

24. An imaging lens according to claim 17, wherein at least one lens having a concave surface facing the object side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is disposed in the rear group.

25. 4.4 < TL / (f × tanωm) < 5.2 (1-2) An imaging lens according to claim 17, which satisfies the conditional expression (1-2) represented by the above formula.

26. 6.3 < (TL × Fno) / (f × tanωm) < 9.5 (7-1) An imaging lens according to claim 25, which satisfies the conditional expression (7-1) represented by the above formula.

27. An imaging lens according to claim 26, wherein at least one lens having a convex surface facing the image side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is disposed in the rear group.

28. An imaging lens according to claim 17, wherein at least one lens having a concave surface facing the image side in the paraxial region and having an inflection point where the concavo-convex shape changes midway from the optical axis toward the peripheral portion is disposed in the rear group.

29. The rear group includes at least one aspherical lens, Among the aspherical lenses included in the rear group, the most image-side aspherical lens is defined as the most image-side aspherical lens, The paraxial radius of curvature of the object-side surface of the most image-side aspherical lens is Rcf, The radius of curvature at the position of the maximum effective diameter of the object-side surface of the most image-side aspherical lens is Ryf, The paraxial radius of curvature of the image-side surface of the most image-side aspherical lens is Rcr, When the radius of curvature at the position of the maximum effective diameter of the image-side surface of the most similar aspherical lens is defined as Ryr, 0.2 < |(1 / Rcf - 1 / Rcr) / (1 / Ryf - 1 / Ryr)| < 4 (8) The imaging lens according to claim 1, which satisfies the conditional expression (8) represented by the above.

30. The number of the focusing lens groups included in the imaging lens is two, Among the two focusing lens groups included in the imaging lens, when the focal length of the focusing lens group on the object side is ff1, Among the two focusing lens groups included in the imaging lens, when the focal length of the focusing lens group on the image side is ff2, 0.2 < |ff1 / ff2| < 5 (9) The imaging lens according to claim 1, which satisfies the conditional expression (9) represented by the above.

31. When the combined focal length of all the lenses on the image side of the most image-side focusing lens group included in the imaging lens is defined as ffR, -1.5 < f / ffR < 1.5 (10) The imaging lens according to claim 1, which satisfies the conditional expression (10) represented by the above.

32. An imaging device including the imaging lens according to any one of claims 1 to 31.

Images