Zoom lens and imaging device having the same

Abstract

To provide a zoom lens with high optical performance, a high magnification ratio, and compact size.SOLUTION: A zoom lens comprises, a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate group having an aperture stop and at least one lens group, and a rear group having at least two lens groups, arranged in order from an object side to an image side, and an interval between adjacent lens groups changes during zooming. The lens group of the rear group arranged closest to the object side has the strongest negative refractive power among lens groups arranged closer to the image side than the aperture stop. In zooming from a wide angle end to a telephoto end, every lens groups included in the first lens group, the intermediate group, and the rear group moves toward the object side, the second lens group moves along a convex trajectory toward the image side. The zoom lens satisfies predetermined inequalities.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a zoom lens, which is suitable for use in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, and cameras for silver halide film. [Background technology]

[0002] In recent years, there has been a demand for zoom lenses that have high optical performance, a high zoom ratio, and a small size for imaging optical systems used in imaging devices.

[0003] In order to obtain a compact imaging optical system with a high zoom ratio, Patent Document 1 discloses an optical system having six lens groups. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 146067 Summary of the Invention [Problem to be solved by the invention]

[0005] The zoom lens of Patent Document 1 has a lens group arranged in order from the object side to the image side: positive, negative, positive, positive, negative, positive. However, because the refractive power of the second lens group is strong, chromatic aberration of magnification at the wide-angle end tends to become large, and fluctuations in curvature of field that occur during zooming tend to become large.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a zoom lens that has high optical performance, a high zoom ratio, and is compact. [Means for solving the problem]

[0007] The optical system of the present invention is a zoom lens that comprises, in order from the object side to the image side, a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate group having an aperture stop and at least one lens group, and a rear group having at least two lens groups, and the spacing between adjacent lens groups changes during zooming. The intermediate group comprises, in order from the object side to the image side, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, and the fifth lens group is arranged closest to the object side of the rear group. The lens group having the strongest negative refractive power among the lens groups arranged closer to the image side than the aperture stop, and during zooming from the wide-angle end to the telephoto end, all of the lens groups included in the first lens group, the intermediate group, and the rear group move toward the object side, and the second lens group moves along a locus convex toward the image side, and when the focal length of the first lens group is f1, the focal length of the second lens group is f2, the back focus of the entire system at the wide-angle end is bfw, and the composite focal length of the rear group at the wide-angle end is fn, 3.30 <f1 / |f2|<5.90 1.40<|f2| / bfw<2.50 1.00 <fn / f2<1.60 The present invention is characterized in that the following conditional expression is satisfied: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a zoom lens that has high optical performance, a high zoom ratio, and is compact. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a zoom lens at the wide-angle end of the first embodiment; [Figure 2] Aberration diagrams of the zoom lens of Example 1 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 3] 10 is a cross-sectional view of a zoom lens at the wide-angle end of Example 2. [Figure 4] Aberration diagrams of the zoom lens of Example 2 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 5]10 is a cross-sectional view of a zoom lens at the wide-angle end according to a third embodiment of the present invention; [Figure 6] Aberration diagrams of the zoom lens of Example 3 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 7] 10 is a cross-sectional view of a zoom lens at the wide-angle end according to a fourth embodiment of the present invention; [Figure 8] Aberration diagrams of the zoom lens of Example 4 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 9] 10 is a cross-sectional view of a zoom lens at the wide-angle end according to a fifth embodiment of the present invention; [Figure 10] Aberration diagrams of the zoom lens of Example 5 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 11] Schematic diagram showing an imaging device DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of an optical system and an imaging apparatus having the same according to the present invention will be described with reference to the accompanying drawings.

[0011] 1, 3, 5, 7, and 9 are cross-sectional views of the zoom lens L0 of Examples 1 to 5, respectively. The zoom lens L0 of each Example is a zoom lens used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, cameras using silver halide film, surveillance cameras, and vehicle-mounted cameras.

[0012] In each lens cross-sectional view, the left is the object side and the right is the image side. The zoom lens L0 of each embodiment may also be used as a projection lens for a projector, etc. In this case, the left is the screen side and the right is the projected image side.

[0013] The solid arrows below each lens cross-sectional view represent the movement locus of each lens group during zooming from the wide-angle end to the telephoto end when focusing on an object at infinity, while the dashed arrows below each lens cross-sectional view represent the movement locus of the lens group that moves during focusing during zooming from the wide-angle end to the telephoto end when focusing on an object at close range.

[0014] In each lens cross-sectional view, SP denotes an aperture stop. When zooming from the wide-angle end to the telephoto end, the aperture stop may move without changing the distance between the lens group and the optical axis, or it may move while changing the distance between the lens group and the optical axis. IP denotes an image plane, and when the zoom lens of each embodiment is used in a digital still camera or digital video camera, the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is disposed thereon. When the zoom lens of each embodiment is used as the photographic optical system of a silver halide film camera, a photosensitive surface corresponding to the film surface is disposed at the image plane IP.

[0015] The zoom lens L0 in each embodiment comprises, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate lens unit Bm including an aperture stop SP and at least one lens unit, and a rear lens unit Br including at least one lens unit. The spacing between adjacent lens units changes during zooming. The lens unit in the rear lens unit Br located closest to the object side is the lens unit with the strongest negative refractive power among the lens units located closer to the image side than the aperture stop SP. Each lens unit may be composed of a single lens or multiple lenses.

[0016] 2, 4, 6, 8, and 10 are aberration diagrams of the zoom lenses of Examples 1 to 5 when focused on an object at infinity at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

[0017] In the spherical aberration diagram, Fno is the F-number, and shows the amount of spherical aberration for the d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm). In the astigmatism diagram, S shows the amount of aberration on the sagittal image plane, and M shows the amount of aberration on the meridional image plane. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration of magnification for the g-line is shown. ω is the half angle of view (°).

[0018] Next, the characteristic configuration of the zoom lens of each embodiment will be described.

[0019] In the zoom lens L0 of each embodiment, the first lens group B1 has a positive refractive power and the second lens group B2 has a negative refractive power, thereby positioning the principal point of the entire system closer to the object and shortening the overall lens length (the distance on the optical axis from the lens surface closest to the object in the zoom lens L0 to the image plane). Furthermore, the zoom lens L0 includes an aperture stop SP, an intermediate group Bm having at least one lens group, and a rear group Br having at least two lens groups. The lens group closest to the object in the rear group Br is the lens group with the strongest negative refractive power among the lens groups positioned closer to the image than the aperture stop SP. Here, when the aperture stop SP is positioned between the lens closest to the object and the lens closest to the image in one lens group, the lens group with the strongest negative refractive power among the lens groups positioned closer to the image than that lens group is designated as the lens group closest to the object in the rear group Br. By positioning the lens groups closer to the image than the aperture stop SP, fluctuations in various aberrations that occur during zooming are suppressed.

[0020] Furthermore, during zooming from the wide-angle end to the telephoto end, the first lens unit B1 moves toward the object side, thereby shortening the overall lens length at the wide-angle end. Furthermore, the third lens unit B3, the lens units included in the intermediate unit Bm, and the lens units included in the rear unit Br all move toward the object side, thereby preventing a large change in the air spacing between adjacent lens units. As a result, it is possible to prevent the heights from the optical axis of on-axis marginal rays and off-axial rays incident on each lens unit at the telephoto end from increasing, allowing the diameter of the lenses arranged in each lens unit to be reduced.

[0021] Furthermore, during zooming from the wide-angle end to the telephoto end, the second lens unit B2 moves along a locus that is convex toward the image side, thereby reducing the amount of field curvature at the intermediate zoom position.

[0022] The zoom lens L0 in each embodiment is configured to satisfy the following conditional expressions. 3.30 <f1 / |f2|<5.90···(1) 1.40<|f2| / bfw<2.50 (2) 1.00 <fn / f2<1.60···(3)

[0023] Here, f1 is the focal length of the first lens unit B1, f2 is the focal length of the second lens unit B2, bfw is the back focal length of the entire system at the wide-angle end, and fn is the combined focal length of the rear lens unit Br at the wide-angle end.

[0024] Conditions (1), (2), and (3) are intended to correct various aberrations, achieve a high zoom ratio, and reduce size.

[0025] If the refractive power of the second lens unit B2 becomes too strong, exceeding the upper limit of conditional expression (1), it becomes difficult to correct chromatic aberration of magnification, particularly at the wide-angle end, and fluctuations in field curvature that occur during zooming. If the refractive power of the second lens unit B2 becomes too weak, falling below the lower limit of conditional expression (1), the amount of movement of the second lens unit B2 during zooming becomes large in order to obtain a high zoom ratio. As a result, the overall lens length becomes long, which is undesirable.

[0026] If the upper limit of conditional expression (2) is exceeded and the back focal length of the entire system at the wide-angle end becomes small, the refractive power of the first lens unit B1 becomes too strong, making it difficult to correct chromatic aberration of magnification, particularly at the wide-angle end.If the lower limit of conditional expression (2) is exceeded and the back focal length of the entire system at the wide-angle end becomes large, the overall lens length becomes long, which is undesirable.

[0027] If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes large enough to exceed the upper limit of conditional expression (3), the principal point of the entire system will be located on the image side. As a result, the overall lens length will undesirably become long. If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes small enough to fall below the lower limit of conditional expression (3), it will become difficult to correct curvature of field and chromatic aberration of magnification, particularly at the wide-angle end.

[0028] With the above configuration, it is possible to realize a zoom lens that has high optical performance, a high zoom ratio, and a small size.

[0029] It is preferable that at least one of the upper and lower limits of the range of values ​​of any one of conditional expressions (1), (2), and (3) is set to the value of the following conditional expressions (1a), (2a), and (3a). 3.70 <f1 / |f2|<5.60···(1a) 1.60<|f2| / bfw<2.40 (2a) 1.10 <fn / f2<1.58···(3a)

[0030] It is even more preferable that at least one of the upper and lower limits of the numerical range of any one of conditional expressions (1), (2), and (3) is set to the range of the following conditional expressions (1b), (2b), and (3b). 4.00 <f1 / |f2|<5.40···(1b) 1.70<|f2| / bfw<2.10 (2b) 1.28 <fn / f2<1.56···(3b)

[0031] Next, a preferred configuration of the zoom lens L0 in each embodiment will be described.

[0032] The first lens group B1 is preferably made up of a single lens, which makes it possible to reduce the thickness of the first lens group B1 in the optical axis direction and shorten the overall lens length.

[0033] The second lens unit B2 is preferably made up of four lenses, which makes it possible to suppress fluctuations in curvature of field that occur particularly during zooming.

[0034] It is preferable that the lens unit in the rear group Br located closest to the object side moves during focusing. Because the height from the optical axis of off-axis rays passing through the lenses in the rear group Br is relatively low, the radial distance that the lens unit moves during focusing can be made small.

[0035] Next, the conditional expressions that are preferably satisfied in the zoom lens L0 of each embodiment will be described.

[0036] It is preferable that the zoom lens L0 of each embodiment satisfies one or more of the following conditional expressions. 1.31 <f1 / ft<2.81···(4) 0.66<|f2| / fw<1.41 (5) 1.14 <Lt / ft<2.49···(6) 0.43 <fp / |fn|<1.04···(7) 0.19<|fn| / f1<0.46 (8) 1.00 <ff / f2<2.74···(9) 0.67 <ff / fn<2.04···(10) 0.28 <fp / ft<0.56···(11) 0.88<|fn| / fw<2.03···(12) 0.38<|fn| / ft<0.85 (13) 2.83 <Lt / fp<5.92···(14) 1.74 <Lt / |fn|<4.37···(15)

[0037] Here, ft is the focal length of the entire system at the telephoto end, and fw is the focal length of the entire system at the wide-angle end. Lt is the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end. fp is the composite focal length of the middle group Bm at the wide-angle end. ff is the focal length of the lens group in the rear group Br that is positioned closest to the object.

[0038] Next, the technical meaning of the above-mentioned conditional expressions (4) to (15) will be explained.

[0039] If the refractive power of the first lens unit B1 becomes too weak by exceeding the upper limit of conditional expression (4), the amount of movement of the first lens unit B1 during zooming becomes large, and the overall lens length at the telephoto end becomes long.If the refractive power of the first lens unit B1 becomes too strong by falling below the lower limit of conditional expression (4), it becomes difficult to correct spherical aberration, especially at the telephoto end.

[0040] If the refractive power of the second lens unit B2 becomes too weak by exceeding the upper limit of conditional expression (5), the amount of movement of the second lens unit B2 during zooming becomes large, and the overall lens length becomes long.If the refractive power of the second lens unit B2 becomes too strong by falling below the lower limit of conditional expression (5), it becomes difficult to correct fluctuations in field curvature that occur during zooming.

[0041] If the upper limit of conditional expression (6) is exceeded, the overall lens length at the telephoto end becomes long. If the lower limit of conditional expression (6) is not reached and the overall lens length at the telephoto end becomes too short, the refractive power of the first lens unit B1 in particular becomes too strong, making it difficult to correct spherical aberration at the telephoto end.

[0042] If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes small by exceeding the upper limit of conditional expression (7), it becomes difficult to correct curvature of field and chromatic aberration of magnification, particularly at the wide-angle end.If the absolute value of the combined focal length of the middle group Bm at the wide-angle end becomes small by falling below the lower limit of conditional expression (7), it becomes difficult to correct spherical aberration and coma, particularly at the wide-angle end.

[0043] If the refractive power of the first lens unit B1 becomes too strong, exceeding the upper limit of conditional expression (8), it becomes difficult to correct spherical aberration, particularly at the telephoto end.If the absolute value of the combined focal length of the rear unit Br at the wide-angle end becomes small, falling below the lower limit of conditional expression (8), it becomes difficult to correct curvature of field and chromatic aberration of magnification, particularly at the wide-angle end.

[0044] If the refractive power of the lens group closest to the object in the rear group Br becomes too weak by exceeding the upper limit of conditional expression (9), the amount of movement of the lens group closest to the object in the rear group Br during zooming becomes large, and the overall length of the lens at the telephoto end becomes long.If the refractive power of the lens group closest to the object in the rear group Br becomes too strong by falling below the lower limit of conditional expression (9), it becomes difficult to correct coma and curvature of field, particularly at the wide-angle end.

[0045] If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes small by exceeding the upper limit of conditional expression (10), it becomes difficult to correct curvature of field and lateral chromatic aberration, particularly at the wide-angle end. If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes large by falling below the lower limit of conditional expression (10), the principal point of the entire system will be located on the image side. As a result, the overall lens length will become long.

[0046] If the composite focal length of the middle unit Bm at the wide-angle end becomes large beyond the upper limit of conditional expression (11), the amount of movement of the middle unit Bm during zooming becomes large, and the overall lens length becomes long.If the composite focal length of the middle unit Bm at the wide-angle end becomes small below the lower limit of conditional expression (11), it becomes difficult to correct spherical aberration and coma, particularly at the wide-angle end.

[0047] If the upper limit of conditional expression (12) is exceeded and the focal length of the entire system at the wide-angle end becomes short, the height from the optical axis of off-axis rays incident on the first lens unit B1 becomes large. As a result, the diameter of the lenses arranged in the first lens unit B1 becomes large, which is undesirable. If the lower limit of conditional expression (12) is exceeded and the absolute value of the combined focal length of the rear unit Br at the wide-angle end becomes small, it becomes difficult to correct curvature of field and chromatic aberration of magnification, especially at the wide-angle end.

[0048] If the absolute value of the composite focal length of the rear group Br at the wide-angle end becomes large beyond the upper limit of conditional expression (13), the amount of movement of the lens groups arranged in the rear group Br during zooming becomes large, and the overall lens length becomes long. If the lower limit of conditional expression (13) is not met and the focal length of the entire system at the telephoto end becomes large, the refractive power of the first lens group B1 becomes too strong. As a result, it becomes difficult to correct spherical aberration, especially at the telephoto end.

[0049] If the upper limit of conditional expression (14) is exceeded and the composite focal length of the middle group Bm at the wide-angle end becomes short, it becomes difficult to correct spherical aberration and coma, particularly at the wide-angle end. If the lower limit of conditional expression (14) is exceeded and the overall lens length at the telephoto end becomes short, the refractive power of the first lens group B1 becomes too strong. As a result, it becomes difficult to correct spherical aberration, particularly at the telephoto end.

[0050] If the absolute value of the combined focal length of the rear group Br at the wide-angle end becomes small by exceeding the upper limit of conditional expression (15), it becomes difficult to correct curvature of field and chromatic aberration of magnification, particularly at the wide-angle end. If the lower limit of conditional expression (15) is not met and the overall lens length becomes short, the refractive power of the first lens group B1 becomes too strong. As a result, it becomes difficult to correct spherical aberration, particularly at the telephoto end.

[0051] It is more preferable to set at least one of the upper and lower limits of the conditional expressions (4) to (15) to the following numerical ranges. 1.49 <f1 / ft<2.59···(4a) 0.75<|f2| / fw<1.30 (5a) 1.30 <Lt / ft<2.30···(6a) 0.49 <fp / |fn|<0.96···(7a) 0.21<|fn| / f1<0.42 (8a) 1.15 <ff / f2<2.53···(9a) 0.77 <ff / fn<1.89···(10a) 0.32 <fp / ft<0.51···(11a) 1.01<|fn| / fw<1.88···(12a) 0.43<|fn| / ft<0.79 ​​(13a) 3.24 <Lt / fp<5.46···(14a) 1.99 <Lt / |fn|<4.04···(15a)

[0052] It is more preferable to set at least one of the upper and lower limits of the conditional expressions (4) to (15) to the following numerical ranges. 1.77 <f1 / ft<2.27···(4b) 0.89<|f2| / fw<1.14 (5b) 1.55 <Lt / ft<2.01···(6b) 0.58 <fp / |fn|<0.84···(7b) 0.26<|fn| / f1<0.37 (8b) 1.36 <ff / f2<2.22···(9b) 0.91 <ff / fn<1.65···(10b) 0.38 <fp / ft<0.45···(11b) 1.20<|fn| / fw<1.64···(12b) 0.51<|fn| / ft<0.69 (13b) 3.85 <Lt / fp<4.78···(14b) 2.36 <Lt / |fn|<3.53···(15b)

[0053] Next, the configuration of the zoom lens L0 in each embodiment will be described in detail.

[0054] [Example 1] The zoom lens L0 of Example 1 is composed of, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate unit Bm, and a rear unit Br. The intermediate unit Bm is composed of, arranged in order from the object side to the image side, a third lens unit B3 with positive refractive power, a fourth lens unit B4 with negative refractive power, and a fifth lens unit B5 with positive refractive power. The rear unit Br is composed of, arranged in order from the object side to the image side, a sixth lens unit B6 with negative refractive power and a seventh lens unit B7 with negative refractive power. By appropriately arranging the lens units with positive refractive power and negative refractive power, various aberrations are effectively corrected throughout the entire zoom range.

[0055] The second lens unit B2 is composed of four lenses, arranged in that order from the object side to the image side: a negative lens, a negative lens, a positive lens, and another negative lens. By configuring the second lens unit B2 with four lenses and arranging a positive lens, fluctuations in chromatic aberration of magnification that occur in the second lens unit B2 during zooming are suppressed.

[0056] Furthermore, in order to reduce the thickness in the optical axis direction and the radial size of the lens groups that move during focusing, the sixth lens group B6, which is made up of one negative lens, moves toward the image side during focusing from an object at infinity to an object at a close distance. Furthermore, the one negative lens that makes up the sixth lens group B6 has a meniscus shape with its convex surface facing the object side. By using a meniscus shape with its convex surface facing the object side, it is possible to suppress fluctuations in spherical aberration that occur during focusing.

[0057] Furthermore, the aperture stop that determines the Fno is located closer to the object side than the third lens unit B3. By locating the aperture stop closer to the object side than the third lens unit B3, which has a relatively small diameter, the diameter of the aperture stop can be made small.

[0058] [Example 2] The zoom lens L0 of Example 2 is composed of, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate unit Bm, and a rear unit Br. The intermediate unit Bm is composed of, arranged in order from the object side to the image side, a third lens unit B3 with positive refractive power and a fourth lens unit B4 with positive refractive power. The rear unit Br is composed of, arranged in order from the object side to the image side, a fifth lens unit B5 with negative refractive power and a sixth lens unit B6 with negative refractive power.

[0059] In the zoom lens L0 of Example 2, the number of lens groups in the rear group Br is reduced compared to Example 1, thereby suppressing the relative decentering between the lens groups that occurs during zooming, making it easier to ensure high optical performance.

[0060] [Example 3] The zoom lens L0 of Example 3 is composed of, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate unit Bm, and a rear unit Br. The intermediate unit Bm is composed of, arranged in order from the object side to the image side, a third lens unit B3 with positive refractive power and a fourth lens unit B4 with positive refractive power. The rear unit Br is composed of, arranged in order from the object side to the image side, a fifth lens unit B5 with negative refractive power and a sixth lens unit B6 with positive refractive power.

[0061] In the zoom lens L0 of Example 3, the refractive power of the sixth lens group B6, which is disposed adjacent to the object side of the fifth lens group B5, which has a negative refractive power compared to Example 2, is set to be positive, thereby making it easier to correct chromatic aberration of magnification that occurs in the fifth lens group B5.

[0062] [Example 4] The zoom lens L0 of Example 4 is composed of, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate unit Bm, and a rear unit Br. The intermediate unit Bm is composed of, arranged in order from the object side to the image side, a third lens unit B3 with positive refractive power, a fourth lens unit B4 with negative refractive power, and a fifth lens unit B5 with positive refractive power. The rear unit Br is composed of, arranged in order from the object side to the image side, a sixth lens unit B6 with negative refractive power, a seventh lens unit B7 with negative refractive power, and an eighth lens unit B8 with positive refractive power.

[0063] The zoom lens L0 of Example 4 has an eighth lens unit B8 with positive refractive power that is arranged adjacent to the seventh lens unit B7 with negative refractive power on the image side, making it easier to suppress fluctuations in field curvature that occur during zooming.

[0064] [Example 5] The zoom lens L0 of Example 5 is composed of, arranged in order from the object side to the image side, a first lens unit B1 with positive refractive power, a second lens unit B2 with negative refractive power, an intermediate unit Bm, and a rear unit Br. The intermediate unit Bm is composed of, arranged in order from the object side to the image side, a third lens unit B3 with positive refractive power. The rear unit Br is composed of, arranged in order from the object side to the image side, a fourth lens unit B4 with negative refractive power and a fifth lens unit B5 with negative refractive power.

[0065] In the zoom lens L0 of Example 5, the lens units arranged in the rear group Br are two lens units with negative refractive power, which makes the absolute value of the combined focal length of the rear group Br relatively small, and as a result, the principal point of the entire system can be positioned on the object side, making it possible to reduce the overall lens length.

[0066] Numerical Examples 1 to 5 corresponding to Examples 1 to 5, respectively, are shown below.

[0067] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial spacing (distance on the optical axis) between the mth surface and the (m+1)th surface. Here, m is the surface number counted from the light incident side. Furthermore, nd represents the refractive index of each optical member with respect to the d-line, and vd represents the Abbe number of the optical member. Note that the Abbe number vd of a certain material is given by the following equation, where Nd, NF, and NC are the refractive indices at the d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), C-line (wavelength 656.3 nm), and g-line (wavelength 435.8 nm): νd=(Nd-1) / (NF-NC) It is expressed as:

[0068] The two surfaces closest to the image correspond to glass blocks (GB). The aspherical shape is such that the X axis is in the direction of the optical axis, the H axis is perpendicular to the optical axis, the direction of light travel is positive, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, and A12 are the respective aspherical coefficients.

[0069]

number

[0070] * means a surface with an aspherical shape. "ex" is 10 -x bf is the back focal length, which is the distance on the optical axis from the lens surface closest to the image in the lens group positioned closest to the image to the image plane, converted into air. Wide angle indicates the wide-angle end, mid-range indicates the intermediate position of the zoom, and telephoto indicates the telephoto end.

[0071] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd νd 1 71.698 7.40 1.49700 81.7 2 -1074.771 (variable) 3 95.769 1.60 1.89190 37.1 4 22.455 7.05 5 -369.959 1.25 1.60311 60.6 6 22.126 7.00 1.90366 31.3 7 412.508 4.86 8 -36.457 1.00 1.85150 40.8 9 -89.252 (variable) 10 (Aperture) ∞ 0.65 11 43.928 3.45 2.00100 29.1 12 -750.000 2.40 13* 106.432 3.70 1.58313 59.4 14* -70.798 2.33 15 -41.445 1.20 1.77047 29.7 16 220.269 (variable) 17 ∞ 1.20 1.85478 24.8 18 28.842 6.10 1.49700 81.7 19 -56.203 (variable) 20* 55.622 3.80 1.58313 59.4 21* -248.880 0.20 22 69.909 7.75 1.59522 67.7 23 -31.690 (variable) 24 71.379 1.10 1.61340 44.3 25 23.380 (variable) 26 -53.964 1.30 1.74400 44.8 27 43.097 4.80 1.92286 20.9 28 -750.000 (variable) 29 ∞ 2.00 1.54400 66.3 30 ∞ (variable) Image plane ∞ Aspheric data Page 13 K = 0.00000e+00 A 4=-5.91734e-06 A 6=-1.25922e-08 A 8=-6.96192e-11 A10=-1.24634e-13 A12= 3.32938e-16 Side 14 K = 0.00000e+00 A 4=-2.81431e-06 A 6=-1.15888e-08 A 8=-1.20810e-10 A10= 3.67743e-13 A12=-6.62375e-16 Page 20 K = 0.00000e+00 A 4=-2.16306e-06 A 6=-3.51669e-08 A 8= 3.80997e-12 A10=-8.02806e-13 A12= 7.68937e-16 Page 21 K = 0.00000e+00 A 4= 1.35282e-05 A 6=-2.86368e-08 A 8= 3.89958e-11 A10=-1.08816e-12 A12= 1.83610e-15 Various data Zoom ratio 2.36 Wide-angle Mid-range Telephoto Focal length 28.80 49.00 67.90 F-number 2.88 2.88 2.92 Half angle of view 34.93 23.82 17.67 Image height 21.64 21.64 21.64 Lens length 132.38 144.25 158.83 bf 15.39 26.31 34.87 d 2 0.85 15.70 26.56 d9 21.64 7.73 2.90 d16 4.86 2.83 2.01 d19 2.00 4.04 4.86 d23 3.22 3.12 2.00 d25 12.68 12.78 13.90 d28 13.00 23.93 32.48 d30 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 1 135.53 B2 3 -27.10 B3 10 51.68 B4 17 -321.04 B5 20 26.75 B6 24 -57.18 B7 26 -120.17

[0072] [Numerical Example 2] Unit: mm Surface Data Surface number rd nd νd 1 64.109 7.17 1.49700 81.5 2 4538.818 (variable) 3 110.231 1.80 1.59522 67.7 4 21.806 8.58 5 -146.659 1.50 1.61340 44.3 6 25.001 4.89 2.00100 29.1 7 94.515 4.46 8 -42.715 1.30 1.53775 74.7 9 -130.569 (variable) 10 (Aperture) ∞ 1.80 11 33.675 2.98 1.59522 67.7 12 92.568 2.87 13* 75.661 3.74 1.58313 59.4 14* -96.472 3.66 15 -28.115 1.22 1.77047 29.7 16 -80.146 (variable) 17* 57.289 5.74 1.58313 59.4 18* -37.418 0.26 19 956.173 1.40 1.85478 24.8 20 71.298 7.39 1.59522 67.7 21 -29.436 (variable) 22 102.308 1.00 1.78470 26.3 23 27.735 (variable) 24 -323.671 1.60 1.75500 52.3 25 27.770 5.39 1.92286 20.9 26 135.653 (variable) 27 ∞ 2.00 1.54400 66.3 28 ∞ (variable) Image plane ∞ Aspheric data Page 13 K = 0.00000e+00 A 4=-4.99308e-06 A 6= 9.56563e-11 A 8= 2.28657e-11 A10= 6.19341e-13 Side 14 K = 0.00000e+00 A 4=-3.09477e-06 A 6= 9.21828e-09 A 8=-7.68728e-11 A10= 9.48917e-13 Page 17 K = 0.00000e+00 A 4=-5.65839e-06 A 6= 5.09383e-08 A 8= 9.98074e-11 A10=-5.71949e-13 A12= 2.69551e-15 Side 18 K = 0.00000e+00 A 4= 2.10447e-05 A 6= 4.37658e-08 A 8= 9.78884e-11 A10=-3.21204e-13 A12= 2.51468e-15 Various data Zoom ratio 2.39 Wide-angle Mid-range Telephoto Focal length 28.80 49.00 68.80 F-number 2.88 2.88 2.88 Half angle of view 34.92 23.68 17.46 Image height 21.64 21.64 21.64 Lens total length 127.13 138.45 151.03 bf 15.39 27.19 37.02 d 2 0.85 14.36 23.61 d9 17.85 6.94 2.00 d16 7.91 4.82 3.27 d21 7.33 4.02 2.00 d23 7.45 10.76 12.79 d26 13.00 24.80 34.63 d28 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 1 130.77 B2 3 -31.26 B3 10 102.51 B4 17 25.35 B5 22 -48.78 B6 24 -330.93

[0073] [Numerical Example 3] Unit: mm Surface Data Surface number rd nd νd 1 69.090 7.40 1.49700 81.5 2 -803.300 (variable) 3 121.485 1.80 1.59522 67.7 4 22.418 8.77 5 -134.878 1.50 1.61340 44.3 6 26.095 4.63 2.00100 29.1 7 103.970 4.45 8 -39.791 1.30 1.53775 74.7 9 -136.339 (variable) 10 (Aperture) ∞ 1.80 11 31.872 3.21 1.59522 67.7 12 95.837 2.80 13* 74.280 3.64 1.58313 59.4 14* -111.093 3.73 15 -28.556 1.33 1.77047 29.7 16 -84.332 (variable) 17* 58.568 5.63 1.58313 59.4 18* -37.260 0.78 19 1434.050 1.40 1.85478 24.8 20 75.530 7.14 1.59522 67.7 21 -29.651 (variable) 22 139.647 1.00 1.78470 26.3 23 27.157 (variable) 24 -3733.823 1.60 1.75500 52.3 25 29.164 5.85 1.92286 20.9 26 204.217 (variable) 27 ∞ 2.00 1.54400 66.3 28 ∞ (variable) Image plane ∞ Aspheric data Page 13 K = 0.00000e+00 A 4=-5.32077e-06 A 6= 7.65017e-09 A 8=-4.96809e-11 A10= 1.19886e-12 Side 14 K = 0.00000e+00 A 4=-4.15343e-06 A 6= 2.86367e-08 A 8=-2.46191e-10 A10= 1.83092e-12 Page 17 K = 0.00000e+00 A 4=-7.75733e-06 A 6= 7.82802e-08 A 8=-5.68650e-11 A10=-5.97309e-15 A12= 2.47205e-15 Side 18 K = 0.00000e+00 A 4= 1.98553e-05 A 6= 5.79944e-08 A 8= 4.92930e-11 A10=-1.42165e-13 A12= 2.87702e-15 Various data Zoom ratio 2.39 Wide-angle Mid-range Telephoto Focal length 28.80 50.00 68.80 F-number 2.88 2.88 2.88 Half angle of view 34.92 23.26 17.46 Image height 21.64 21.64 21.64 Lens length 127.13 139.11 151.03 bf 15.39 27.80 37.28 d 2 0.85 14.97 23.52 d9 18.11 6.72 2.00 d16 6.55 3.38 2.00 d21 7.69 4.67 2.88 d23 7.19 10.21 12.00 d26 13.00 25.41 34.89 d28 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 1 128.37 B2 3 -30.04 B3 10 95.30 B4 17 25.64 B5 22 -43.13 B6 24 900.00

[0074] [Numerical Example 4] Unit: mm Surface Data Surface number rd nd νd 1 79.594 7.59 1.49700 81.7 2 -835.318 (variable) 3 73.280 1.60 1.89190 37.1 4 21.548 7.37 5 -369.959 1.25 1.60311 60.6 6 21.168 6.95 1.90366 31.3 7 289.158 4.06 8 -36.165 1.00 1.85150 40.8 9 -91.177 (variable) 10 (Aperture) ∞ 0.60 11 44.013 3.47 2.00100 29.1 12 -750.000 2.36 13* 107.718 3.73 1.58313 59.4 14* -69.983 2.47 15 -39.067 1.20 1.77047 29.7 16 199.294 (variable) 17 ∞ 1.20 1.85478 24.8 18 29.445 6.20 1.49700 81.7 19 -54.091 (variable) 20* 54.923 4.13 1.58313 59.4 21* -150.167 0.20 22 75.662 6.75 1.59522 67.7 23 -33.194 (variable) 24 83.342 1.10 1.61340 44.3 25 24.485 (variable) 26 -41.988 1.30 1.74400 44.8 27 59.444 3.71 1.92286 20.9 28 -750.000 (variable) 29 150.000 3.00 2.00100 29.1 30 -1033.371 (variable) 31 ∞ 2.00 1.54400 66.3 32 ∞ (variable) Image plane ∞ Aspheric data Page 13 K = 0.00000e+00 A 4=-4.20525e-06 A 6=-3.82772e-08 A 8= 2.77210e-10 A10=-1.84598e-12 A12= 4.13300e-15 Side 14 K = 0.00000e+00 A 4=-7.76915e-07 A 6=-4.58293e-08 A 8= 3.25378e-10 A10=-1.82949e-12 A12= 3.89584e-15 Page 20 K = 0.00000e+00 A 4=-4.04521e-06 A 6=-3.55365e-08 A 8= 3.62232e-11 A10=-4.52586e-13 A12=-5.35347e-16 Page 21 K = 0.00000e+00 A 4= 9.66538e-06 A 6=-2.63857e-08 A 8= 2.80285e-11 A10=-5.56106e-13 A12= 1.71401e-16 Various data Zoom ratio 2.36 Wide-angle Mid-range Telephoto Focal length 28.80 49.00 67.90 F-number 2.88 2.88 2.88 Half angle of view 34.93 23.82 17.67 Image height 21.64 21.64 21.64 Lens length 133.93 147.58 164.79 bf 15.39 26.87 33.17 d 2 0.93 17.37 29.29 d9 21.92 7.63 3.07 d16 4.14 2.68 2.05 d19 2.00 3.46 4.09 d23 3.31 3.13 2.00 d25 12.42 12.60 13.73 d28 1.00 1.00 4.55 d30 13.00 24.49 30.79 d32 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 1 146.62 B2 3 -27.63 B3 10 54.59 B4 17 -400.00 B5 20 26.50 B6 24 -56.93 B7 26 -74.69 B8 29 131.02

[0075] [Numerical Example 5] Unit: mm Surface Data Surface number rd nd νd 1 70.085 7.30 1.49700 81.7 2 -1574.782 (variable) 3 60.612 1.60 1.89190 37.1 4 21.042 9.52 5 -77.202 1.25 1.60311 60.6 6 23.779 5.97 1.90366 31.3 7 -399.826 3.48 8 -33.442 1.00 1.85150 40.8 9 -68.541 (variable) 10 (Aperture) ∞ 0.60 11 40.797 3.56 2.00100 29.1 12 3588.308 3.82 13* 88.425 3.79 1.58313 59.4 14* -75.107 2.30 15 -42.118 1.20 1.77047 29.7 16 122.233 2.24 17 ∞ 1.20 1.85478 24.8 18 25.603 6.52 1.49700 81.7 19 -54.236 1.00 20* 50.362 4.17 1.58313 59.4 21* -173.006 0.20 22 73.842 7.91 1.59522 67.7 23 -30.992 (variable) 24 73.148 1.10 1.61340 44.3 25 23.688 (variable) 26 -46.222 1.30 1.74400 44.8 27 38.043 5.96 1.92286 20.9 28 -264.067 (variable) 29 ∞ 2.00 1.54400 66.3 30 ∞ (variable) Image plane ∞ Aspheric data Page 13 K = 0.00000e+00 A 4=-9.51958e-06 A 6= 3.27515e-08 A 8=-6.64755e-10 A10= 3.31255e-12 A12=-7.78473e-15 Side 14 K = 0.00000e+00 A 4=-6.21422e-06 A 6= 2.98009e-08 A 8=-6.62840e-10 A10= 3.56637e-12 A12=-8.29869e-15 Page 20 K = 0.00000e+00 A 4=-4.06926e-06 A 6=-4.50722e-08 A 8= 1.02428e-10 A10=-1.37819e-12 A12= 1.60037e-15 Page 21 K = 0.00000e+00 A 4= 1.13553e-05 A 6=-3.18660e-08 A 8= 4.63977e-11 A10=-1.17301e-12 A12= 1.72462e-15 Various data Zoom ratio 2.36 Wide-angle Mid-range Telephoto Focal length 28.80 50.00 67.90 F-number 2.88 2.88 2.88 Angle of view 34.93 23.40 17.67 Image height 21.64 21.64 21.64 Lens total length 132.41 142.47 156.50 BF 2.39 2.39 2.39 d 2 0.85 16.48 27.47 d 9 23.29 7.35 2.90 d23 1.76 2.21 1.00 d25 14.14 13.73 15.15 d28 13.00 23.33 30.62 d30 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 1 135.21 B2 3 -28.05 B3 10 28.37 B4 24 -57.60 B5 26 -130.23

[0076] The table below shows the various values ​​for each example.

[0077] [Table 1]

[0078] [Imaging device] Next, an embodiment of a digital still camera (imaging device) using a zoom lens of the present invention as an imaging optical system will be described with reference to Fig. 11. In Fig. 11, 11 denotes an imaging optical system configured with any of the zoom lenses described in Examples 1 to 5. 12 denotes an imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor that is built into a camera body 10 and receives and photoelectrically converts an optical image formed by the imaging optical system 11. The camera body 10 may be a so-called single-lens reflex camera that has a quick-turn mirror, or a so-called mirrorless camera that does not have a quick-turn mirror.

[0079] In this way, by applying the zoom lens L0 of the present invention to an imaging device such as a digital still camera, it is possible to obtain high-resolution images with a wide angle of view.

[0080] The disclosure of each embodiment includes the following configuration.

[0081] (Configuration 1) A zoom lens comprising, arranged in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, an intermediate group having an aperture stop and at least one lens group, and a rear group having at least two lens groups, wherein the spacing between adjacent lens groups changes during zooming, the lens group in the rear group arranged closest to the object side is the lens group with the strongest negative refractive power among the lens groups arranged closer to the image side than the aperture stop, During zooming from the wide-angle end to the telephoto end, all lens groups included in the first lens group, the intermediate lens group, and the rear lens group move toward the object side, and the second lens group moves along a locus convex toward the image side, Let f1 be the focal length of the first lens group, f2 be the focal length of the second lens group, bfw be the back focus of the entire system at the wide-angle end, and fn be the composite focal length of the rear lens group at the wide-angle end. 3.30 <f1 / |f2|<5.90 1.40<|f2| / bfw<2.50 1.00 <fn / f2<1.60 A zoom lens characterized by satisfying the following conditional expressions:

[0082] (Configuration 2) When the focal length of the entire system at the telephoto end is ft, 1.31 <f1 / ft<2.81 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

[0083] (Configuration 3) When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 3. The zoom lens according to configuration 1 or 2, wherein the following condition is satisfied:

[0084] (Configuration 4) Let Lt be the distance on the optical axis from the lens surface closest to the object at the telephoto end to the lens surface closest to the image at the telephoto end, and ft be the focal length of the entire system at the telephoto end. 1.14 <Lt / ft<2.49 4. The zoom lens according to any one of the configurations 1 to 3, wherein the following condition is satisfied:

[0085] (Configuration 5) When the composite focal length of the intermediate group at the wide-angle end is fp, 0.43 <fp / |fn|<1.04 5. The zoom lens according to any one of configurations 1 to 4, wherein the following condition is satisfied:

[0086] (Configuration 6) 0.19<|fn| / f1<0.46 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied:

[0087] (Configuration 7) 7. A zoom lens according to any one of configurations 1 to 6, wherein the lens group in the rear group that is located closest to the object moves during focusing.

[0088] (Configuration 8) When the focal length of the lens unit located closest to the object side in the rear group is ff, 1.00 <ff / f2<2.74 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied:

[0089] (Configuration 9) When the focal length of the lens unit located closest to the object side in the rear group is ff, 0.67 <ff / fn<2.04 9. The zoom lens according to any one of configurations 1 to 8, wherein the following condition is satisfied:

[0090] (Configuration 10) When the composite focal length of the intermediate lens group at the wide-angle end is fp and the focal length of the entire system at the telephoto end is ft, 0.28 <fp / ft<0.56 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied:

[0091] (Configuration 11) When the focal length of the entire system at the wide-angle end is fw, 0.88<|fn| / fw<2.03 11. The zoom lens according to any one of configurations 1 to 10, wherein the following condition is satisfied:

[0092] (Configuration 12) When the focal length of the entire system at the telephoto end is ft, 0.38<|fn| / ft<0.85 12. The zoom lens according to any one of configurations 1 to 11, wherein the following condition is satisfied:

[0093] (Configuration 13) Let Lt be the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end, and fp be the composite focal length of the intermediate lens group at the wide-angle end. 2.83 <Lt / fp<5.92 13. The zoom lens according to any one of configurations 1 to 12, wherein the following condition is satisfied:

[0094] (Configuration 14) When the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end is Lt, 1.74 <Lt / |fn|<4.37 14. The zoom lens according to any one of configurations 1 to 13, wherein the following condition is satisfied:

[0095] (Configuration 15) The zoom lens according to any one of configurations 1 to 14, wherein the first lens group is made up of one lens.

[0096] (Configuration 16) The zoom lens according to any one of configurations 1 to 15, wherein the second lens group is made up of four lenses.

[0097] (Configuration 17) The zoom lens according to any one of configurations 1 to 16, wherein the intermediate group comprises, arranged in order from the object side to the image side, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power.

[0098] (Configuration 18) The zoom lens according to any one of configurations 1 to 16, wherein the intermediate group comprises, in order from the object side to the image side, a third lens group with positive refractive power and a fourth lens group with positive refractive power.

[0099] (Configuration 19) The zoom lens according to any one of configurations 1 to 16, wherein the rear group is composed of a lens group with negative refractive power and a lens group with negative refractive power, arranged in this order from the object side to the image side.

[0100] (Configuration 20) The zoom lens according to any one of configurations 1 to 16, wherein the rear group is composed of a lens group with negative refractive power and a lens group with positive refractive power, arranged in this order from the object side to the image side.

[0101] (Configuration 21) The zoom lens according to any one of configurations 1 to 16, wherein the rear group consists of a lens group with negative refractive power, a lens group with negative refractive power, and a lens group with positive refractive power, arranged in this order from the object side to the image side.

[0102] (Configuration 22) A zoom lens according to any one of claims 1 to 21; an imaging device having an imaging element that receives an image formed by the zoom lens;

[0103] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0104] L0 zoom lens B1 First lens group B2 Second lens group Bm intermediate group Br rear group

Claims

1. A zoom lens comprising, arranged in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, an intermediate group having an aperture stop and at least one lens group, and a rear group having at least two lens groups, wherein the spacing between adjacent lens groups changes during zooming, the intermediate group comprises, arranged in order from the object side to the image side, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power; the lens group in the rear group arranged closest to the object side is the lens group with the strongest negative refractive power among the lens groups arranged closer to the image side than the aperture stop, during zooming from the wide-angle end to the telephoto end, all of the lens groups included in the first lens group, the intermediate lens group, and the rear lens group move toward the object side, and the second lens group moves along a locus convex toward the image side, When the focal length of the first lens group is f1, the focal length of the second lens group is f2, the back focus of the entire system at the wide-angle end is bfw, and the composite focal length of the rear group at the wide-angle end is fn, 3.30<f1 / |f2|<5.90 1.40<|f2| / bfw<2.50 1.00<fn / f2<1.60 A zoom lens characterized by satisfying the following conditional expressions:

2. When the focal length of the entire system at the telephoto end is ft, 1.31<f1 / ft<2.81 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side at the telephoto end is Lt and the focal length of the entire system at the telephoto end is ft, 1.14<Lt / ft<2.49 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the composite focal length of the intermediate group at the wide-angle end is fp, 0.43<fp / |fn|<1.04 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. 0.19<|fn| / f1<0.46 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. 2. The zoom lens according to claim 1, wherein the lens unit located closest to the object side of said rear group moves during focusing.

8. When the focal length of the lens unit located closest to the object side in the rear group is ff, 1.00<ff / f2<2.74 8. The zoom lens according to claim 7, wherein the following condition is satisfied:

9. When the focal length of the lens unit located closest to the object side in the rear group is ff, 0.67<ff / fn<2.04 8. The zoom lens according to claim 7, wherein the following condition is satisfied:

10. When the composite focal length of the intermediate lens group at the wide-angle end is fp and the focal length of the entire system at the telephoto end is ft, 0.28<fp / ft<0.56 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. When the focal length of the entire system at the wide-angle end is fw, 0.88<|fn| / fw<2.03 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. When the focal length of the entire system at the telephoto end is ft, 0.38<|fn| / ft<0.85 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. Let Lt be the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end, and fp be the composite focal length of the intermediate lens group at the wide-angle end. 2.83<Lt / fp<5.92 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. When the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end is Lt, 1.74<Lt / |fn|<4.37 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

15. 2. The zoom lens according to claim 1, wherein the first lens group consists of one lens.

16. 2. The zoom lens according to claim 1, wherein the second lens group is made up of four lenses.

17. 2. The zoom lens according to claim 1, wherein the intermediate group comprises, in order from the object side to the image side, a third lens group having a positive refractive power and a fourth lens group having a positive refractive power.

18. 2. The zoom lens according to claim 1, wherein the rear group comprises, in order from the object side to the image side, a lens group having a negative refractive power and a lens group having a negative refractive power.

19. 2. The zoom lens according to claim 1, wherein the rear group comprises, in order from the object side to the image side, a lens group having a negative refractive power and a lens group having a positive refractive power.

20. 2. The zoom lens according to claim 1, wherein the rear group comprises, in order from the object side to the image side, a lens group with negative refractive power, a lens group with negative refractive power, and a lens group with positive refractive power.

21. When the focal length of the entire system at the telephoto end is ft, 1.31<f1 / ft<2.81 21. The zoom lens according to claim 3, wherein the following condition is satisfied:

22. When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 21. The zoom lens according to claim 4, wherein the following condition is satisfied:

23. When the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side at the telephoto end is Lt and the focal length of the entire system at the telephoto end is ft, 1.14<Lt / ft<2.49 21. The zoom lens according to claim 5, wherein the following condition is satisfied:

24. When the focal length of the entire system at the telephoto end is ft and the focal length of the entire system at the wide-angle end is fw, 1.31<f1 / ft<2.81 0.66<|f2| / fw<1.41 21. The zoom lens according to claim 4, wherein the following condition is satisfied:

25. When the focal length of the entire system at the telephoto end is ft and the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end is Lt, 1.31<f1 / ft<2.81 1.14<Lt / ft<2.49 21. The zoom lens according to claim 5, wherein the following condition is satisfied:

26. When the focal length of the entire system at the telephoto end is ft, the focal length of the entire system at the wide-angle end is fw, and the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end is Lt, 0.66<|f2| / fw<1.41 1.14<Lt / ft<2.49 21. The zoom lens according to claim 5, wherein the following condition is satisfied:

27. When the focal length of the entire system at the telephoto end is ft, the focal length of the entire system at the wide-angle end is fw, and the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end is Lt, 1.31<f1 / ft<2.81 0.66<|f2| / fw<1.41 1.14<Lt / ft<2.49 21. The zoom lens according to claim 5, wherein the following condition is satisfied:

28. A zoom lens comprising, arranged in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, an intermediate group having an aperture stop and at least one lens group, and a rear group having at least two lens groups, wherein the spacing between adjacent lens groups changes during zooming, the rear group comprises, arranged in order from the object side to the image side, a lens group having negative refractive power, a lens group having negative refractive power, and a lens group having positive refractive power; the lens group in the rear group arranged closest to the object side is the lens group with the strongest negative refractive power among the lens groups arranged closer to the image side than the aperture stop, during zooming from the wide-angle end to the telephoto end, all of the lens groups included in the first lens group, the intermediate lens group, and the rear lens group move toward the object side, and the second lens group moves along a locus convex toward the image side, When the focal length of the first lens group is f1, the focal length of the second lens group is f2, the back focus of the entire system at the wide-angle end is bfw, and the composite focal length of the rear group at the wide-angle end is fn, 3.30<f1 / |f2|<5.90 1.40<|f2| / bfw<2.50 1.00<fn / f2<1.60 A zoom lens characterized by satisfying the following conditional expressions:

29. A zoom lens according to any one of claims 1 to 20; an imaging device having an imaging element that receives an image formed by the zoom lens;

Images