ZOOM LENS AND IMAGE DEVICE

Abstract

Zoom lens consisting as a whole of four or five lens groups, which, starting from one side of the object, comprise a first lens group (G1) with a positive refractive power, a second lens group (G2) with a negative refractive power, one or two intermediate lens groups comprising an mp lens group with a positive refractive power, and a rearmost lens group located at the image-side position of the entire system and having a positive refractive power. where a change in magnification is achieved by changing all distances between the adjacent lens groups, an A-cement lens (CA), consisting of a positive lens and a negative lens cemented together in this order starting from the object side, is arranged at the object-side position of the second lens group (G2), a B-cement lens (CB), consisting of a positive lens and a negative lens, is arranged on the image side of the A-cement lens (CA) and on the object side of the mp-lens group, a C-cement lens (CC), consisting of a positive lens and a negative lens, arranged in the mp lens group, and the following conditional expressions (1) and (2) are satisfied: 60 < ν dBn 0.0055 < θ gFBn + 0.00162 ν dBn − 0.6415 < 0.050 where vdBn is an Abbe number of the negative lens forming the B-cement lens (CB) and θgFBn is a partial dispersion ratio of the negative lens forming the B-cement lens (CB).

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a zoom lens suitable for use with, in particular, digital cameras, interchangeable-lens digital cameras, etc., and to an imaging device equipped with the zoom lens. Description of the state of the art

[0002] So-called constant aperture zoom lenses with a zoom ratio of approximately 2.5 to 3.0 and a constant maximum aperture of approximately F2.8 or F4 over the entire zoom range are known.

[0003] Such a zoom lens has a four-group or five-group configuration, comprising, for example, in order starting from the object side, a first lens group which has a positive refractive power and is fixed during a magnification change, a second lens group which has a negative refractive power and has a strong magnification change effect, approximately one or two magnification change groups which are provided in addition to the second lens group and include a lens group with a positive refractive power, and a rearmost lens group which is fixed during a magnification change.

[0004] Zoom lenses having the configuration described above are known as those disclosed in patent documents 1 to 5. [Previous state documents][Patent documents] [Patent Document 1] Japanese Unexamined Patent Publication JP 2013-7878 A [Patent document 2] Japanese unexamined patent publication JP 2012-58619 A [Patent document 3] Japanese unexamined patent publication JP 2012-93548 A [Patent document 4] Japanese unexamined patent publication JP 2011-99964 A [Patent document 5] Japanese unexamined patent publication JP 2013-160997 A

[0005] Furthermore, zoom lenses with the configuration described above are also known from the revealed writings JP 5 475 401 B2 and JP 2011-99 964 A. SUMMARY OF THE INVENTION

[0006] In the type of zoom lens described above, the correction of chromatic aberration is one of the important problems. To achieve this correction, a known, conventional method uses a material with low dispersion and high anomalous dispersion to form a positive lens, which constitutes the first lens group and through which the thickest beam of light passes at the telephoto end.However, chromatic aberration also tends to occur at the moving lens groups, such as the second lens group and the third lens group, which are located behind the first lens group, and the chromatic aberration that occurs at the second lens group, which has a strong magnification change effect, or at the magnification change group, which has a negative refractive power, results in a significant variation in chromatic aberration between the wide-angle end and the telephoto end.

[0007] In the zoom lens described above, the second lens group is formed by approximately four or five lenses. As a relatively simple configuration example, the second lens group of Patent Document 1 is formed by four lenses, comprising, in order starting from the object side, a negative lens, a cemented lens formed by a negative lens and a positive lens, and a negative lens. A conventional way to correct chromatic aberration is by appropriately arranging a cemented lens, and exactly one cemented lens is used in the example above. To correct chromatic aberration, a material with an Abbe number of 70.3 is used to form the negative lens, and a material with an Abbe number of 23.8 is used to form the positive lens, creating a large difference between the Abbe numbers of the two lenses to achieve achromatization.Although the material forming the negative lens has low dispersion, it does not have high abnormal dispersion, and in this case it is difficult to suppress secondary chromatic aberration.

[0008] Patent document 2 discloses an example in which a material with a high anomalous dispersion, equivalent to that of S-FPL51, available from Ohara Inc., is used to form the negative lens that forms the cemented lens arranged in the second lens group. Patent document 2 also uses an additional cemented lens in the second lens group to correct chromatic aberration. However, the third lens group, which is another moving lens group, is formed by two individual lenses, and it is difficult to achieve sufficient achromatic correction.

[0009] Patent document 3 discloses an example in which a material with a high anomalous dispersion is used, equivalent to that of J-FKH1, available from Hikari Glass Co., Ltd. However, in patent document 3, the second lens group comprises exactly one cemented lens and the first lens comprises two cemented lenses, resulting in an increase in the size of the zoom lens.

[0010] In patent document 4, the second lens group comprises two cemented lenses, and the third lens group, which is another magnification-changing group, also comprises a cemented lens. While this configuration simplifies the suppression of variations in chromatic aberration during magnification changes, the second lens group does not use a low dispersion glass material with high anomalous dispersion, and it is difficult to achieve sufficient correction of chromatic aberration.

[0011] In patent document 5, each of the second, third, and fourth lens groups comprises a cemented lens, and this configuration simplifies the suppression of variations in chromatic aberration during magnification changes. However, the second and third lens groups, which are negative lens groups, do not use a low dispersion and high anomalous dispersion material like the materials used in patent documents 2 and 3.

[0012] In view of the circumstances described above, the present invention is directed to provide a zoom lens with high optical performance with successfully suppressed primary chromatic aberration and secondary chromatic aberration, as well as an imaging device equipped with the zoom lens.

[0013] A zoom lens according to the invention consists as a whole of four or five lens groups, which, starting from the object side, comprise a first lens group with a positive refractive power, a second lens group with a negative refractive power, (exactly) one or two center lens groups, comprising an mp lens group with a positive refractive power, and a rearmost lens group, which is arranged at the image-side position of the entire system and has a positive refractive power, wherein a change in magnification is effected by changing all distances between the adjacent lens groups. an A-cement lens, consisting of a positive lens and a negative lens cemented together in this order starting from the object side, is arranged at the object-side position of the second lens group, a B-cement lens, consisting of (exactly) one positive lens and (exactly) one negative lens, is arranged on the image side of the A-cement lens and on the object side of the mp-lens group, a C-cement lens, consisting of (exactly) one positive lens and (exactly) one negative lens, arranged in the mp lens group, and the following conditional expressions (1) and (2) are satisfied: 60<νdBn 0.0055<θgFBn+0.00162νdBn−0.6415<0.050 where vdBn is an Abbe number of the negative lens forming the B-cement lens and θgFBn is a partial dispersion ratio of the negative lens forming the B-cement lens.

[0014] It should be noted that the mp lens group is not part of a lens group (a sub-lens group) and is (precisely) an independent lens group. Here, "independent lens group" refers to a lens group in which the distance between the lens group and the adjacent lens group changes during a change in magnification. In the case that the middle lens group consists of two lens groups, and both of the two lens groups have a positive refractive power, the mp lens group can be either of the two lens groups.

[0015] In the zoom lens according to the invention, it is preferred that the first lens group remains fixed relative to the image plane during a change in magnification.

[0016] It is preferred that the rearmost lens group remains fixed relative to the image plane during the magnification change.

[0017] It is preferred that the first lens group comprises at least two positive lenses and that the following condition expression (3) is satisfied: 80.5<νd1p where vd1p is an average Abbe number of positive lenses in the first lens group.

[0018] It is preferred that the following condition expression (4) is satisfied: 57<νdCp where vdCp is an abbreviation of the positive lens forming the C cement lens.

[0019] It is preferred that focusing from an object at infinity to the next object is effected by moving only the entire mp lens group or a part of the lenses forming the mp lens group along the optical axis, and it is particularly preferred that focusing is effected by moving only the entire mp lens group.

[0020] It is preferred that the mp lens group includes the C cement lens and (exactly) one positive lens.

[0021] It is preferred that the first lens group includes at least (exactly) one negative lens that satisfies the following condition expression (5): 28<νd1n<45 where vd1n is an Abbe number of the negative lens in the first lens group.

[0022] It is preferred that the rearmost lens group, starting from the object side, consists of a front group with a positive refractive power, a middle group with a negative refractive power and a rear group with a positive refractive power, the front group consisting of three positive lenses and (exactly) one negative lens, and that image stabilization is achieved by moving only the middle group in directions perpendicular to the direction of the optical axis.

[0023] In this case, it is preferred that the center group consists of two negative lenses and (exactly) one positive lens.

[0024] The zoom lens according to the invention can consist of four lens groups, which, starting from the object side, consist of the first lens group, the second lens group, the mp lens group and the rearmost lens group, or of five lens groups, which, starting from the object side, consist of the first lens group, the second lens group, a lens group with a negative refractive power, the mp lens group and the rearmost lens group.

[0025] It is preferred that the second lens group includes two or more positive lenses and two or more negative lenses.

[0026] It is preferred that the first lens group, starting from the object side, consists of a negative lens, a positive lens, a positive lens and a positive lens.

[0027] It is preferred that the first lens group includes at least (exactly) one positive lens and that the following condition expression (6) is satisfied: 83<νd1m where vd1m is the largest Abbe number of at least (exactly) one positive lens in the first lens group.

[0028] It is preferred that the first lens group includes at least (exactly) one positive lens and that the positive lens with the highest Abbe number in the first lens group is a single lens.

[0029] It is preferred that an aperture is arranged at the position furthest from the object of the lens group furthest from the rear.

[0030] It is preferred that the positive lens forming the A-kitt lens has a center thickness that is greater than the center thickness of the negative lens forming the A-kitt lens.

[0031] An imaging device according to the invention comprises the zoom lens described above.

[0032] It should be noted that the expression "consisting of / comprising" as used here means that the zoom lens may include, in addition to the elements mentioned above: lenses that have essentially no refractive power; optical elements other than lenses, such as an aperture, a mask, a cover glass, and filters; and mechanical components such as a lens flange, a lens tube, an image sensor, an image stabilization mechanism, etc.

[0033] The Abbe numbers refer to the d-line (the wavelength of 587.6 nm), and the partial dispersion ratio θgF is expressed by the following formula: θgF=(ng−nF) / (nF−nC), where ng is a refractive index with respect to the g-line (the wavelength of 435.8 nm), nF is a refractive index with respect to the F-line (the wavelength of 486.1 nm) and nC is a refractive index with respect to the C-line (the wavelength of 656.3 nm).

[0034] The sign (positive or negative) regarding the surface shape and refractive power of any lens that includes an aspheric surface refers to the paraxial (near-axis) region.

[0035] The zoom lens according to the invention consists as a whole of four or five lens groups, which, starting from the object side, comprise a first lens group with a positive refractive power, a second lens group with a negative refractive power, (exactly) one or two intermediate lens groups, comprising an mp lens group with a positive refractive power, and a rearmost lens group, which is arranged at the image-side position of the entire system and has a positive refractive power, wherein a change in magnification is effected by changing all distances between the adjacent lens groups, an A-cement lens, consisting of a positive lens and a negative lens, which are cemented together in this order starting from the object side, is arranged at the image-side position of the second lens group, and a B-cement lens.consisting of (exactly) one positive lens and (exactly) one negative lens, arranged on the image side of the A cemented lens and on the object side of the mp lens group, a C cemented lens consisting of (exactly) one positive lens and (exactly) one negative lens, arranged in the mp lens group, and the following condition expressions (1) and (2) are satisfied: , 60<νdBn 0.0055<θgFBn+0.00162νdBn−0.6415<0.050

[0036] This configuration allows for the achievement of a zoom lens with high optical performance, successfully suppressing primary and secondary chromatic aberration.

[0037] The imaging lens according to the invention, which is equipped with the zoom lens according to the invention, allows the achievement of high-quality images with reduced primary chromatic aberration and secondary chromatic aberration. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a sectional view illustrating the lens configuration of a zoom lens according to an embodiment of the present invention (a zoom lens of Example 1). Fig. Figure 2 is a sectional view illustrating the lens configuration of a zoom lens from Example 2 of the invention. Fig. Figure 3 is a sectional view illustrating the lens configuration of a zoom lens from Example 3 of the invention. Fig. Figure 4 is a sectional view illustrating the lens configuration of a zoom lens from Example 4 of the invention. Fig. Figure 5 is a sectional view illustrating the lens configuration of a zoom lens from Example 5 of the invention. Fig. Figure 6 is a sectional view illustrating the lens configuration of a zoom lens from Example 6 of the invention. Fig.Figure 7 is a sectional view illustrating the lens configuration of a zoom lens from Example 7 of the invention. Fig. Figure 8 is a sectional view illustrating the lens configuration of a zoom lens from Example 8 of the invention. Fig. Figure 9 is a sectional view illustrating the lens configuration of a zoom lens from Example 9 of the invention. Fig. Figure 10 is a sectional view illustrating the lens configuration of a zoom lens from Example 10 of the invention. Fig. Figure 11 is a sectional view illustrating the lens configuration of a zoom lens from Example 11 of the invention. Fig. Figure 12 shows aberration diagrams of the zoom lens of Example 1 of the invention. Fig. Figure 13 shows aberration diagrams of the zoom lens of Example 2 of the invention. Fig. Figure 14 shows aberration diagrams of the zoom lens of Example 3 of the invention. Fig. Figure 15 shows aberration diagrams of the zoom lens of Example 4 of the invention. Fig. Figure 16 shows aberration diagrams of the zoom lens of Example 5 of the invention. Fig. Figure 17 shows aberration diagrams of the zoom lens of Example 6 of the invention, Fig. Figure 18 shows aberration diagrams of the zoom lens of Example 7 of the invention, Fig. Figure 19 shows aberration diagrams of the zoom lens of Example 8 of the invention, Fig. Figure 20 shows aberration diagrams of the zoom lens from Example 9 of the invention. Fig. Figure 21 shows aberration diagrams of the zoom lens of Example 10 of the invention. Fig. Figure 22 shows aberration diagrams of the zoom lens of Example 11 of the invention, Fig. Figure 23 shows lateral aberration diagrams of the zoom lens of Example 1 of the invention. Fig.Figure 24 shows lateral aberration diagrams of the zoom lens of Example 1 of the invention (with image stabilization), Fig. Figure 25 shows lateral aberration diagrams of the zoom lens of Example 2 of the invention. Fig. Figure 26 shows lateral aberration diagrams of the zoom lens of Example 2 of the invention (with image stabilization), Fig. Figure 27 shows lateral aberration diagrams of the zoom lens of Example 3 of the invention. Fig. Figure 28 shows lateral aberration diagrams of the zoom lens of Example 3 of the invention (with image stabilization), Fig. Figure 29 shows lateral aberration diagrams of the zoom lens of Example 4 of the invention. Fig. Figure 30 shows lateral aberration diagrams of the zoom lens of Example 4 of the invention (with image stabilization), Fig. Figure 31 shows lateral aberration diagrams of the zoom lens of Example 5 of the invention. Fig.Figure 32 shows lateral aberration diagrams of the zoom lens of Example 5 of the invention (with image stabilization), Fig. Figure 33 shows lateral aberration diagrams of the zoom lens of Example 6 of the invention, Fig. Figure 34 shows lateral aberration diagrams of the zoom lens of Example 6 of the invention (with image stabilization), Fig. Figure 35 shows lateral aberration diagrams of the zoom lens of Example 7 of the invention, Fig. Figure 36 shows lateral aberration diagrams of the zoom lens of Example 7 of the invention (with image stabilization), Fig. Figure 37 shows lateral aberration diagrams of the zoom lens of Example 8 of the invention. Fig. Figure 38 shows lateral aberration diagrams of the zoom lens of Example 8 of the invention (with image stabilization), Fig. Figure 39 shows lateral aberration diagrams of the zoom lens of Example 9 of the invention, Fig.Figure 40 shows lateral aberration diagrams of the zoom lens of Example 9 of the invention (with image stabilization), Fig. Figure 41 shows lateral aberration diagrams of the zoom lens of Example 10 of the invention. Fig. Figure 42 shows lateral aberration diagrams of the zoom lens of Example 10 of the invention (with image stabilization), Fig. Figure 43 shows lateral aberration diagrams of the zoom lens of Example 11 of the invention. Fig. Figure 44 shows lateral aberration diagrams of the zoom lens of Example 11 of the invention (with image stabilization), Fig. Figure 45 is a perspective view showing the front of an imaging device according to an embodiment of the invention, and Fig. 46 is a perspective view showing the back of the building. Fig. 45 shows the imaging device. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0038] An embodiment of the present invention is described in detail below with reference to the drawings. Fig. Figure 1 is a sectional view illustrating the lens configuration of a zoom lens according to one embodiment of the invention. The Fig. The illustrated configuration example is the same as the configuration of a zoom lens from Example 1, which is described later. Fig. In the diagram, the left side is the object side and the right side is the image side. An aperture stop St shown in the drawing does not necessarily represent its size or shape, but rather its position along the optical axis Z.

[0039] As in Fig.As shown in Figure 1, this zoom lens consists, in order starting from the object side, of a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power, a third lens group G3 with a positive refractive power (corresponding to an mp lens group according to the invention) and a fourth lens group G4 with a positive refractive power (corresponding to a furthest rear lens group according to the invention), wherein a change in magnification is effected by changing all distances between the adjacent lens groups.

[0040] When this zoom lens is used with an imaging device, it is preferable to provide a cover glass, a prism, and various filters, such as an infrared cutoff filter and a low-pass filter, etc., between the optical system and an imaging plane, depending on the configuration of the camera on which the lens is mounted. In the Fig.In the example shown, an optical element PP in the form of a plane-parallel plate, representing the elements described above, is arranged between the lens system and the imaging plane Sim. At the object-side position of the second lens group G2, an A-cemented lens CA is arranged, formed by a positive lens L21 and a negative lens L22 cemented together in that order starting from the object side. A B-cemented lens CB, formed by a negative lens L23 and a positive lens L24 cemented together in that order starting from the object side, is arranged on the image side of the A-cemented lens CA.Arranging the A-cement lens CA, which is formed by a positive lens and a negative lens cemented together in that order starting from the object side, at the object-side position of the second lens group G2 in this manner is advantageous for correcting longitudinal chromatic aberration. Furthermore, arranging the B-cement lens CB, which is formed by exactly one positive lens and exactly one negative lens, on the image side of the A-cement lens CA and on the object side of the third lens group G3 (the mp lens group) is advantageous for correcting secondary lateral chromatic aberration.

[0041] In the third lens group G3 (the mp lens group), a C-cement lens CC is arranged, formed by a positive lens L32 and a negative lens L33, cemented together in that order starting from the object side. Arranging the C-cement lens CC, formed by exactly one positive lens and exactly one negative lens, in the third lens group G3 (the mp lens group) in this manner allows for the suppression of chromatic aberration during zooming.

[0042] The zoom lens according to the invention is configured to satisfy the following condition expressions (1) and (2). Condition expression (1) relates to the Abbe number of the negative lens L23 that forms the B-cement lens CB, and condition expression (2) relates to the partial dispersion ratio of the negative lens L23 that forms the B-cement lens CB. Fulfilling the low dispersion defined by condition expression (1) and the anomalous dispersion defined by condition expression (2) allows for a well-balanced correction of primary chromatic aberration (longitudinal and lateral chromatic aberration) and secondary chromatic aberration over the entire zoom range.

[0043] Fulfilling the lower limit of condition expression (1) ensures a sufficient difference between the refractive indices of the negative lens L23 and the positive lens L24, which form the B-cement lens CB, to provide adequate correction for primary chromatic aberration. Furthermore, fulfilling the lower limit of condition expression (1) eliminates the need to select a material with high dispersion for the positive lens L24, which forms the B-cement lens CB. This is advantageous for correcting secondary chromatic aberration. Fulfilling the upper limit of condition expression (1) allows for the creation of the desired refractive power without reducing the absolute values ​​of the radius of curvature of the lens surfaces of the negative lens L23, thus enabling the successful suppression of aberrations occurring at the lens surfaces.

[0044] Fulfilling the lower limit of condition expression (2) is advantageous for correcting secondary chromatic aberration. A material that fulfills the upper limit of condition expression (2) exhibits a certain degree of refractive index. Therefore, fulfilling the upper limit of condition expression (2) allows the creation of a desired refractive power without reducing the absolute values ​​of the radius of curvature of the lens surfaces of the negative lens L23. This allows for the successful suppression of aberrations occurring at the lens surfaces and is also advantageous for correcting coma aberration at the wide-angle end.

[0045] It should be noted that higher performance can be achieved if the following conditional expressions (1-1), (1-2), (1-3) and / or (2-1) are satisfied. 60<νdBn 60<νdBn<100 65<νdBn 65<νdBn<90 0.0055<θgFBn+0.00162νdBn−0.6415<0.050 0.010<θgFBn+0.00162νdBn−0.6415<0.045 where vdBn is an Abbe number of the negative lens forming the B-cement lens and θgFBn is a partial dispersion ratio of the negative lens forming the B-cement lens.

[0046] In the zoom lens of this embodiment, it is preferred that the first lens group G1 remains fixed relative to the image plane Sim during magnification changes. Fixing the first lens group G1 in this manner allows for a simplification of the frame structure. Compared to a configuration in which the first lens group G1 is moved forward to its telephoto end position, this configuration offers advantages such as reducing the influence of lens decentering due to lens frame bending, etc., and simplifying the use of a dustproof, weatherproof structure.

[0047] It is preferred that the fourth lens group G4 (the rearmost lens group) remains fixed relative to the image plane Sim during magnification changes. Reducing the number of lens groups that need to be moved in this way allows for a reduction in the influence of decentering. Furthermore, this configuration allows for the suppression of any variation in the f-number during magnification changes, which is advantageous for creating a zoom lens with a constant aperture.

[0048] It is preferred if the first lens group G1 comprises at least two positive lenses and satisfies the following condition (3). Using a material with low dispersion in the first lens group G1, through which the thickest beam passes at the telephoto end, in this manner allows for successful correction of longitudinal chromatic aberration, particularly on the telephoto end. It should be noted that higher performance can be achieved if the following condition (3-1) is satisfied. 80.5<νd1p 80.5<νd1p<100 where vd1p is an average Abbe number of positive lenses in the first lens group.

[0049] It is preferred if the following condition expression (4) is satisfied. Satisfying the lower limit of condition expression (4) allows for successful correction of longitudinal chromatic aberration. Furthermore, satisfying the lower limit of condition expression (4) allows for the suppression of variation in chromatic aberration between the wide-angle and telephoto ends. Satisfying the upper limit of condition expression (4) allows for well-balanced correction of chromatic aberrations. It should be noted that higher performance can be achieved if the following condition expression (4-1), (4-2), or (4-3) is satisfied. 57<νdCp 57<νdCp<85 59<νdCp 59<νdCp<85 where vdCp is an abbreviation of the positive lens forming the C cement lens.

[0050] It is preferred if focusing from an object at infinity to the nearest object is achieved by moving either the entire third lens group G3 (the mp lens group) or a portion of the lenses forming the third lens group G3 (the mp lens group) along the optical axis. Using the internal focusing system described above allows for a reduction in the weight of the focusing lens, thereby accelerating the autofocus operation. Furthermore, achieving focus by moving the entire third lens group G3 (the mp lens group) allows for the suppression of aberration variations during focusing.

[0051] It is preferred that the third lens group G3 (the mp lens group) comprises a C-cement lens CC and exactly one positive lens. This configuration allows for the successful correction of aberrations at the third lens group G3 (the mp lens group) and the suppression of aberration variation during magnification changes. Furthermore, using the third lens group G3 (the mp lens group) as a focusing group, as described above, allows for the suppression of chromatic aberration variation during focusing.

[0052] It is preferred if the first lens group G1 comprises at least (exactly) one negative lens that satisfies the following condition expression (5). Satisfying the lower limit of condition expression (5) is advantageous for correcting secondary chromatic aberration. Satisfying the upper limit of condition expression (5) prevents the refractive powers of the negative and positive lenses from becoming excessively strong, which is advantageous for correcting spherical aberration, particularly on the telephoto end. It should be noted that higher performance can be achieved if the following condition expression (5-1) is satisfied. 28<νd1n<45 30<νd1n<43 where vd1n is an Abbe number of the negative lens in the first lens group.

[0053] It is preferred that the fourth lens group G4 (the rearmost lens group) consists, in sequence from the object side, of a front group with a positive refractive power, a middle group with a negative refractive power, and a rear group with a positive refractive power, wherein the front group consists of three positive lenses and exactly one negative lens, and image stabilization is achieved by moving only the middle group in directions perpendicular to the direction of the optical axis. Providing the image stabilization group with a refractive power opposite to that of the lens groups in front of and behind the image stabilization group in this manner allows the image stabilization group to be provided with a strong refractive power, and this permits a straightforward increase in the sensitivity of the image shift to a shift of the image stabilization group.This, in turn, allows for a reduction in the displacement range of the image stabilization lens, which is necessary to achieve the same degree of image stabilization effect. This configuration also allows the lens groups to cancel each other's aberrations.

[0054] In this case, it is preferred that the center group consists of two negative lenses and exactly one positive lens. Using three lenses to form the image stabilization group in this way allows for the suppression of decentering coma and a variation in chromatic aberration associated with a shift in the image stabilization group. The zoom lens according to the invention can consist of four lens groups, which, starting from the object side, comprise the first lens group, the second lens group, the mp lens group, and the rearmost lens group, or it can consist of five lens groups, which, starting from the object side, comprise the first lens group, the second lens group, a lens group with a negative refractive power, the mp lens group, and the rearmost lens group.Minimizing the number of lens groups and designing the zoom lens with the four-group configuration described above allows for a simplification of the frame structure and a reduction in the influence of decentering. Designing a zoom lens with the five-lens-group configuration is advantageous for suppressing variation in aberrations and for suppressing field curvature. The zoom lens of this embodiment features the four-group configuration.

[0055] It is preferred if the second lens group G2 comprises two or more positive lenses and two or more negative lenses. The second lens group G2 with the configuration described above allows for trouble-free correction of aberrations, even if the second lens group G2 is provided with a strong refractive power to achieve a size reduction of the front lens element or to reduce the range of motion of the second lens group G2. This allows for successful correction of coma aberration and chromatic aberration, especially at the wide-angle end.

[0056] It is preferred that the first lens group G1, starting from the object side, consists of a negative lens, a positive lens, a positive lens, and a positive lens. The first lens group G1, comprising three positive lenses in this manner, allows for successful correction of chromatic and spherical aberrations, particularly at the telephoto end. In cases where the first lens group G1, for purposes of magnification, etc., has a strong refractive power as a whole, the configuration described above still allows the refractive power to be distributed among the lenses, resulting in smaller aberrations at each lens surface.

[0057] It is preferred if the following condition (6) is satisfied. Satisfaction of condition (6) allows successful correction of longitudinal chromatic aberration and secondary chromatic aberration at the telephoto end. 83<νd1m where vd1m is the largest Abbe number of positive lenses in the first lens group.

[0058] It is preferred if the positive lens with the highest Abbe number in the first lens group G1 is a single lens. A material that satisfies the above condition expression (6) exhibits high anomalous dispersion and is very advantageous for correcting chromatic aberration; however, such a material is soft and difficult to work with when used to form a cemented lens. It is therefore preferred to use such a material to form a single lens.

[0059] It is preferred that the aperture diaphragm St be located at the object-side position of the fourth lens group G4 (the rearmost lens group). Positioning the aperture diaphragm St at the object-side position of the fourth lens group G4 (the rearmost lens group), instead of between the lenses of the fourth lens group G4, simplifies the frame structure. Furthermore, if the fourth lens group G4 (the rearmost lens group) remains fixed relative to the image plane Sim during magnification changes, a constant-aperture zoom lens can still be constructed without changing the aperture diaphragm diameter.

[0060] It is preferred if the positive lens forming the A-cement lens CA has a center thickness greater than the center thickness of the negative lens forming the A-cement lens CA. This configuration allows the positive lens to be provided with sufficient refractive power, which is advantageous for correcting chromatic aberration.

[0061] If the zoom lens is used in a harsh environment, it is preferable if it has a multi-layer protective coating. In addition to the protective coating, the zoom lens can also be equipped with an anti-reflective coating to reduce ghosting, etc., during use.

[0062] In the Fig.In the example shown, the optical element PP is positioned between the lens system and the imaging plane Sim. However, instead of placing the various filters, such as a low-pass filter and a filter that cuts off a specific wavelength range, between the lens system and the imaging plane Sim, the various filters can be positioned between the lenses, or coatings with the same functions as the various filters can be applied to the lens surfaces of some of the lenses.

[0063] Numerical examples of the zoom lens according to the invention are described below.

[0064] First, a zoom lens from Example 1 will be described. Fig. Figure 1 is a sectional view illustrating the lens configuration of the zoom lens from Example 1. It should be noted that in Fig. 1 and Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. In Figure 11, which corresponds to Examples 2 to 11 and is described later, the left side is the object side and the right side is the image side. The aperture stop St shown in the drawings does not necessarily represent its size or shape, but rather its position along the optical axis Z. In the drawings, the symbol "Focus" denotes a lens group used to achieve focusing, and the symbol "Ois" denotes a lens group used to achieve image stabilization.

[0065] The zoom lens of Example 1 has a four-group configuration, which, starting from the object side, consists of a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power, a third lens group G3 (the mp lens group) with a positive refractive power, and a fourth lens group G4 (the furthest rear lens group) with a positive refractive power.

[0066] Table 1 shows basic lens data for the zoom lens of Example 1, Table 2 shows data on specifications of the zoom lens, and Table 3 shows data on distances between moving surfaces of the zoom lens. The following description explains the meanings of the symbols used in the tables with respect to Example 1. The same explanations generally apply to those relating to Examples 2 through 11.

[0067] In the lens data shown in Table 1, each value in the "Surface No." column represents a surface number, where the object-side surface of the element furthest from the object is the first surface and the number is incremented sequentially towards the image side. Each value in the "Radius of Curvature" column represents the radius of curvature of the corresponding surface, and each value in the "Spacing Distance" column represents the distance along the optical axis Z between the respective surface and the next surface. Each value in the "nd" column represents the refractive index of the corresponding optical element with respect to the d-line (wavelength of 587.6 nm), each value in the "vd" column represents the Abbe number of the corresponding optical element with respect to the d-line (wavelength of 587.6 nm), and each value in the "θgF" column represents the partial dispersion ratio of the corresponding optical element.

[0068] It should be noted that the partial dispersion ratio θgF is represented by the following formula: θgF=(ng−nF) / (nF−nC), where ng is a refractive index with respect to the g-line (the wavelength of 435.8 nm), nF is a refractive index with respect to the F-line (the wavelength of 486.1 nm) and nC is a refractive index with respect to the C-line (the wavelength of 656.3 nm).

[0069] The sign for the radius of curvature is specified such that a positive radius of curvature indicates a surface shape that is convex towards the object side, and a negative radius of curvature indicates a surface shape that is convex towards the image side. The basic lens data also includes aperture diaphragm (St) and optical element (PP) data, and the surface number and the text "(Aperture)" are shown in the surface number column in the position corresponding to the aperture diaphragm (St). In the lens data shown in Table 1, the value of each surface distance that changes during magnification is represented by the symbol "DD[Surface Number]". The numerical values ​​corresponding to each DD[Surface Number] at the wide-angle end, the center position, and the telephoto end are shown in Table 3.

[0070] The specifications shown in Table 2 include values ​​for zoom magnification, focal length f', back focus Bf', F-number Fno, and total angle of view 2ω at the wide-angle end, the middle position, and the telephoto end.

[0071] Regarding the basic lens data, the data on specifications, and the data on distances to moving surfaces, the angular unit is degrees and the length unit is millimeters; however, any other suitable units can be used, as optical systems are usable when scaled up or down proportionally. [Table 1] Example 1 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 274,96102 2,390 1,80100 34,97 0,58642 2 77,90148 7,850 1,49700 81,54 0,53748 3 -1203,47290 0,200 4 97,12166 5,000 1,43875 94,94 0,53433 5 3892,40898 0,200 6 62,76476 6,000 1,49700 81,54 0,53748 7 583,05158 DD[7] 8 110,71627 5,710 1,72047 34,71 0,58350 9 -42,66766 1,550 1,62230 53,17 0,55424 10 24,37958 4,958 11 -78,43069 1,260 1,49700 81,54 0,53748 12 25,54612 5,501 1,84661 23,88 0,62072 13 105,31259 4,001 14 -28,87373 1,250 1,91082 35,25 0,58224 15 391,32559 DD

[15] 16 -349,16836 2,950 1,80100 34,97 0,58642 17 -38,22034 0,100 18 63,65733 4,310 1,61800 63,33 0,54414 19 -39,25049 1,150 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 27,59915 6,985 1,49700 81,54 0,53748 23 -58,46986 0,150 24 34,60348 2,550 1,65412 39,68 0,57378 25 95,96990 1,610 26 -53,62431 1,210 1,90366 31,31 0,59481 27 22,84961 6,512 1,49700 81,54 0,53748 28 -84,57206 2,500 29 293,69564 3,771 1,80518 25,42 0,61616 30 -23,04083 0,950 1,58913 61,13 0,54067 31 33,63593 2,693 32 -43,53615 1,050 1,80100 34,97 0,58642 33 62,25169 3,752 34 51,53927 6,921 1,80000 29,84 0,60178 35 -39,86271 3,848 36 50,27571 7,368 1,48749 70,24 0,53007 37 -26,02866 1,310 1,80518 25,42 0,61616 38 -69,72800 3,069 39 -30,18711 1,310 1,91082 35,25 0,58224 40 -51,30966 26,063 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 2] Example 1 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,517 92,224 135,968 Bf' 29,940 29,940 29,940 FNo. 2,88 2,89 2,88 2ω[°] 30,4 17,0 11,6 [Table 3] Example 1 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,647 24,961 34,686 DD

[15] 11,849 7,355 2,477 DD

[20] 32,001 13,182 8,334

[0072] Fig. Figure 12 shows aberration diagrams of the zoom lens from Example 1. The in Fig.The 12 aberration diagrams shown above are those of spherical aberration, offense against the sine condition, astigmatism, distortion, and lateral chromatic aberration at the wide-angle end, in that order starting from the left side, which is in the middle. Fig. The 12 aberration diagrams shown are those of spherical aberration, violation of the sine condition, astigmatism, distortion, and lateral chromatic aberration at the center position, in that order starting from the left, and those in Fig.The 12 aberration diagrams shown below are those of spherical aberration, violation of the sine condition, astigmatism, distortion, and lateral chromatic aberration at the telephoto end, in that order starting from the left. The aberration diagrams for spherical aberration, violation of the sine condition, astigmatism, and distortion show those with respect to the d-line (wavelength 587.6 nm), which is used as a reference wavelength. The aberration diagrams for spherical aberration show those with respect to the d-line (wavelength 587.6 nm), the C-line (wavelength 656.3 nm), the F-line (wavelength 486.1 nm), and the g-line (wavelength 435.8 nm), each represented by a solid line, a long dashed line, a short dashed line, and a gray line, respectively.The aberration diagrams for astigmatism show those in the sagittal and tangential directions, each represented by a solid line and a short dashed line, respectively. The aberration diagrams for lateral chromatic aberration show those for the C-line (wavelength 656.3 nm), the F-line (wavelength 486.1 nm), and the g-line (wavelength 435.8 nm), each represented by a long dashed line, a short dashed line, and a gray line, respectively. It should be noted that these longitudinal aberration diagrams show aberrations when the zoom lens is focused on an object at infinity. In the aberration diagrams for spherical aberration and violation of the sine condition, the symbol "Fno." denotes the "F-number," and in the other aberration diagrams, the symbol "ω" denotes the "half-angle of view."

[0073] Fig.Figure 23 shows lateral aberration diagrams of the zoom lens from Example 1 without image stabilization. Fig. Figure 23 shows, in order from top to bottom, lateral aberration diagrams at the wide-angle end, the center position, and the telephoto end. Of the lateral aberration diagrams shown in two columns, the left-hand diagrams show those with respect to the tangential direction, and the right-hand diagrams show those with respect to the sagittal direction. Of the lateral aberration diagrams, the top one shows aberrations at the center of the image plane, the two in the middle show aberrations at the position where the image height is 80% of the maximum image height on the positive (+) side, and the two at the bottom show aberrations at the position where the image height is 80% of the maximum image height on the negative (-) side. Fig.Figure 24 shows lateral aberration diagrams of the zoom lens from Example 1 with image stabilization. The contents of the aberration diagrams are similar to or identical to those without image stabilization. It should be noted that in Fig. 23 and Fig. 24 aberrations with respect to the d-line (wavelength of 587.6 nm), the C-line (wavelength of 656.3 nm), the F-line (wavelength of 486.1 nm), and the g-line (wavelength of 435.8 nm) are shown, each with a solid line, a long dashed line, a short dashed line, and a gray line, respectively. These lateral aberration diagrams show lateral aberrations when the zoom lens is focused on an object at infinity. The symbol "ω" in the aberration diagrams means "half field of view".

[0074] The symbols, meanings and descriptions of the various data from Example 1 described above also apply to the examples described below, unless otherwise stated, and the same explanations are not repeated in the following description.

[0075] The following describes a zoom lens from Example 2. The zoom lens from Example 2 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 2 is a sectional view illustrating the lens configuration of the zoom lens from Example 2. Table 4 shows basic lens data for the zoom lens from Example 2, Table 5 shows data on the specifications of the zoom lens, and Table 6 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 13 shows aberration diagrams of the zoom lens, Fig.Figure 25 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 26 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 4] Example 2 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 147,14684 2,312 1,90366 31,31 0,59481 2 71,34579 6,799 1,49700 81,54 0,53748 3 4466,14983 0,262 4 82,92060 4,599 1,45562 91,31 0,53429 5 222,61947 0,209 6 72,46651 7,001 1,48749 70,24 0,53007 7 2229,87611 DD[7] 8 83,14047 6,305 1,64769 33,79 0,59393 9 -54,99973 1,501 1,61772 49,81 0,56035 10 22,65737 6,228 11 -129,46710 1,009 1,53775 74,70 0,53936 12 23,41440 5,501 1,84661 23,88 0,62072 13 90,28797 3,246 14 -32,56444 0,999 1,91082 35,25 0,58224 15 -754,10763 DD

[15] 16 -139,28102 3,100 1,91082 35,25 0,58224 17 -37,20322 0,100 18 45,57357 5,511 1,48749 70,24 0,53007 19 -45,00113 1,100 1,80518 25,42 0,61616 20 302,73331 DD

[20] 21 (aperture) ∞ 1,300 22 29,00638 5,564 1,53775 74,70 0,53936 23 -83,12098 0,182 24 28,22418 2,499 1,65412 39,68 0,57378 25 48,84185 1,900 26 -76,98887 1,210 1,90366 31,31 0,59481 27 20,91613 7,501 1,53775 74,70 0,53936 28 -71,39743 3,663 29 101,15891 4,706 1,80518 25,42 0,61616 30 -24,63022 0,882 1,60300 65,44 0,54022 31 26,11599 3,199 32 -41,59530 0,899 1,80100 34,97 0,58642 33 49,70954 2,255 34 43,72156 5,600 1,80000 29,84 0,60178 35 -36,00246 2,992 36 36,16338 5,708 1,48749 70,24 0,53007 37 -25,22381 1,199 1,80518 25,42 0,61616 38 -148,78795 4,102 39 -27,60609 1,199 1,91082 35,25 0,58224 40 -43,25152 23,562 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 5] Example 2 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,492 92,178 135,901 Bf' 27,440 27,440 27,440 FNo. 2,89 2,89 2,89 2ω[°] 30,2 17,0 11,6 [Table 6] Example 2 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,199 24,644 34,908 DD

[15] 12,356 7,391 1,751 DD

[20] 31,802 13,322 8,698

[0076] The following describes a zoom lens from Example 3. The zoom lens from Example 3 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 3 is a sectional view illustrating the lens configuration of the zoom lens in Example 3. Table 7 shows basic lens data for the zoom lens in Example 3, Table 8 shows data on the specifications of the zoom lens, and Table 9 shows data on the distances between moving surfaces of the zoom lens. Fig.Figure 14 shows aberration diagrams of the zoom lens, Fig. Figure 27 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 28 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 7] Example 3 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 263,09263 2,312 1,88100 40,14 0,57010 2 65,86876 7,199 1,49700 81,54 0,53748 3 -571,64100 0,262 4 65,97392 6,200 1,45562 91,31 0,53429 5 1175,27258 0,209 6 81,36467 5,500 1,53775 74,70 0,53936 7 614,16494 DD[7] 8 120,18724 5,912 1,72047 34,71 0,58350 9 -42,77946 1,200 1,62230 53,17 0,55424 10 26,30170 5,468 11 -3031,67199 1,009 1,43875 94,94 0,53433 12 24,69032 4,403 1,84661 23,88 0,62072 13 52,10852 4,001 14 -29,01944 0,999 1,88300 40,76 0,56679 15 677,75184 DD

[15] 16 -624,58221 3,099 1,91082 35,25 0,58224 17 -48,99609 0,100 18 84,61141 4,859 1,62041 60,29 0,54266 19 -45,52887 1,100 1,84666 23,78 0,62054 20 -11814,82817 DD

[20] 21 (aperture) ∞ 1,300 22 28,94841 7,001 1,49700 81,54 0,53748 23 -70,94964 2,298 24 35,48837 2,499 1,65412 39,68 0,57378 25 125,19811 1,799 26 -55,44889 1,210 1,90366 31,31 0,59481 27 24,47948 7,501 1,49700 81,54 0,53748 28 -71,45146 2,001 29 93,11345 4,160 1,80518 25,42 0,61616 30 -26,87211 0,849 1,58313 59,37 0,54345 31 26,83474 3,501 32 -31,98401 0,901 1,80100 34,97 0,58642 33 64,79704 2,718 34 52,34160 5,499 1,80000 29,84 0,60178 35 -36,46191 4,001 36 56,45949 7,310 1,48749 70,24 0,53007 37 -23,44294 1,199 1,80518 25,42 0,61616 38 -60,82914 2,999 39 -26,37941 1,199 1,91082 35,25 0,58224 40 -35,96318 22,238 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 8] Example 3 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 3,1 f' 50,359 90,150 157,119 Bf' 26,122 26,122 26,122 FNo. 2,89 2,90 2,92 2ω[°] 31,0 17,2 10,0 [Table 9] Example 3 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,199 24,327 37,203 DD

[15] 16,502 10,829 1,100 DD

[20] 32,001 14,546 11,399

[0077] The following describes a zoom lens from Example 4. The zoom lens from Example 4 has a lens group configuration similar to that of the zoom lens from Example 1. Fig.Figure 4 is a sectional view illustrating the lens configuration of the zoom lens in Example 4. Table 10 shows basic lens data for the zoom lens in Example 4, Table 11 shows data on the specifications of the zoom lens, and Table 12 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 15 shows aberration diagrams of the zoom lens, Fig. Figure 29 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 30 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 10] Example 4 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 188,13090 2,312 1,80610 33,27 0,58845 2 76,50883 7,200 1,49700 81,54 0,53748 3 -3204,67292 0,262 4 71,91851 6,200 1,43875 94,94 0,53433 5 718,81472 0,209 6 63,83157 5,500 1,43875 94,94 0,53433 7 286,11890 DD[7] 8 127,11673 5,510 1,72047 34,71 0,58350 9 -52,90722 1,200 1,62230 53,17 0,55424 10 24,99227 6,501 11 -273,45110 1,511 1,59522 67,74 0,54426 12 26,07897 5,501 1,84661 23,88 0,62072 13 90,43692 4,000 14 -28,20939 1,001 1,88300 40,76 0,56679 15 -219,42843 DD

[15] 16 4368,42118 3,099 1,91082 35,25 0,58224 17 -45,70178 0,100 18 75,53670 5,511 1,49700 81,54 0,53748 19 -37,32451 1,100 1,80518 25,42 0,61616 20 -582,89400 DD

[20] 21 (aperture) ∞ 1,300 22 31,57617 7,001 1,49700 81,54 0,53748 23 -84,25408 1,501 24 32,66369 2,500 1,65412 39,68 0,57378 25 452,11337 1,799 26 -77,71874 1,210 1,90366 31,31 0,59481 27 23,15115 5,500 1,49700 81,54 0,53748 28 -93,31207 2,001 29 664,84163 4,161 1,80518 25,42 0,61616 30 -28,96139 1,201 1,58313 59,37 0,54345 31 23,87736 3,200 32 -37,84433 0,899 1,80100 34,97 0,58642 33 66,37072 2,215 34 45,41616 8,001 1,80518 25,42 0,61616 35 -36,36637 1,453 36 44,07982 7,310 1,48749 70,24 0,53007 37 -23,31946 1,200 1,80518 25,42 0,61616 38 -147,09849 2,999 39 -27,43891 1,200 1,91082 35,25 0,58224 40 -35,75126 22,213 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 11] Example 4 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 3,0 f' 51,153 91,572 154,995 Bf' 26,096 26,096 26,096 FNo. 2,89 2,89 2,89 2ω[°] 30,6 17,2 10,2 [Table 12] Example 4 Zoom distances with respect to Wide-angle end center End of phone DD[7] 1,199 22,851 34,047 DD

[15] 17,079 11,080 1,673 DD

[20] 28,994 13,341 11,552

[0078] The following describes a zoom lens from Example 5. The zoom lens from Example 5 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 5 is a sectional view illustrating the lens configuration of the zoom lens in Example 5. Table 13 shows basic lens data for the zoom lens in Example 5, Table 14 shows data on the specifications of the zoom lens, and Table 15 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 16 shows aberration diagrams of the zoom lens, Fig. Figure 31 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 32 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 13] Example 5 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 308,24145 2,390 1,80100 34,97 0,58642 2 78,18266 7,850 1,49700 81,54 0,53748 3 -340,82791 0,200 4 66,71039 6,600 1,43875 94,94 0,53433 5 720,82813 0,200 6 71,57189 4,950 1,49700 81,54 0,53748 7 271,98720 DD[7] 8 100,51474 5,710 1,72047 34,71 0,58350 9 -47,31525 1,550 1,62230 53,17 0,55424 10 25,05895 5,799 11 -81,14905 1,260 1,49700 81,54 0,53748 12 26,42066 5,385 1,84661 23,88 0,62072 13 110,30764 3,945 14 -30,83422 1,250 1,91082 35,25 0,58224 15 339,66055 DD

[15] 16 -578,30556 2,950 1,80100 34,97 0,58642 17 -44,53935 0,100 18 76,28815 4,310 1,61800 63,33 0,54414 19 -43,38154 1,150 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 27,81766 6,849 1,49700 81,54 0,53748 23 -58,16078 0,150 24 34,51417 2,550 1,65412 39,68 0,57378 25 107,98255 1,610 26 -54,74993 1,210 1,90366 31,31 0,59481 27 23,44507 5,499 1,49700 81,54 0,53748 28 -83,55949 2,500 29 343,99918 3,771 1,80518 25,42 0,61616 30 -24,56535 0,950 1,58913 61,13 0,54067 31 39,79185 2,559 32 -45,16452 1,050 1,80100 34,97 0,58642 33 60,11939 4,533 34 51,91667 6,541 1,80000 29,84 0,60178 35 -39,70261 4,000 36 54,95096 6,950 1,48749 70,24 0,53007 37 -27,73386 1,310 1,80518 25,42 0,61616 38 -89,67633 3,413 39 -27,15780 1,310 1,91082 35,25 0,58224 40 -45,53256 24,577 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 14] Example 5 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,4 f' 51,515 92,219 125,696 Bf' 28,455 28,455 28,455 FNo. 2,88 2,89 2,89 2ω[°] 30,4 17,0 12,4 [Table 15] Example 5 - Distances with respect to zoom Wide-angle end Mid-Tele end DD[7] 1,199 22,040 29,321 DD

[15] 14,144 8,593 3,929 DD

[20] 27,855 12,565 9,948

[0079] The following describes a zoom lens from Example 6. The zoom lens from Example 6 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 6 is a sectional view illustrating the lens configuration of the zoom lens in Example 6. Table 16 shows basic lens data for the zoom lens in Example 6, Table 17 shows data on the specifications of the zoom lens, and Table 18 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 17 shows aberration diagrams of the zoom lens, Fig. Figure 33 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 34 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 16] Example 6 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 379,59503 2,390 1,80100 34,97 0,58642 2 87,06343 7,850 1,49700 81,54 0,53748 3 -423,40525 0,200 4 77,08956 6,600 1,43875 94,94 0,53433 5 505,15031 0,200 6 74,14509 4,950 1,49700 81,54 0,53748 7 428,65265 DD[7] 8 95,00168 5,710 1,72047 34,71 0,58350 9 -42,18184 1,550 1,62230 53,17 0,55424 10 25,82252 4,852 11 -127,50772 1,260 1,49700 81,54 0,53748 12 27,56506 4,000 1,84661 23,88 0,62072 13 102,12490 3,395 14 -31,04306 1,250 1,91082 35,25 0,58224 15 593,08219 DD

[15] 16 -587,37289 2,950 1,80100 34,97 0,58642 17 -43,88242 0,100 18 78,12881 4,310 1,61800 63,33 0,54414 19 -42,34007 1,150 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 27,72433 6,373 1,49700 81,54 0,53748 23 -59,65321 0,150 24 34,01198 2,550 1,65412 39,68 0,57378 25 93,88248 1,610 26 -54,41210 1,210 1,90366 31,31 0,59481 27 23,35543 5,569 1,49700 81,54 0,53748 28 -77,98799 2,500 29 394,61491 3,771 1,80518 25,42 0,61616 30 -24,49939 0,950 1,58913 61,13 0,54067 31 37,65964 2,511 32 -48,39346 1,050 1,80100 34,97 0,58642 33 60,29812 4,948 34 52,39389 5,299 1,80000 29,84 0,60178 35 -39,28541 3,134 36 53,75550 7,501 1,48749 70,24 0,53007 37 -26,62926 1,310 1,80518 25,42 0,61616 38 -98,73317 6,921 39 -26,89205 1,310 1,91082 35,25 0,58224 40 -46,99846 18,856 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 17] Example 6 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,4 f' 51,515 92,219 125,696 Bf' 22,736 22,736 22,736 FNo. 2,88 2,89 2,88 2ω[°] 30,4 17,0 12,4 [Table 18] Example 6 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,199 26,087 34,640 DD

[15] 13,697 7,573 2,495 DD

[20] 32,001 13,236 9,762

[0080] The following describes a zoom lens from Example 7. The zoom lens from Example 7 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 7 is a sectional view illustrating the lens configuration of the zoom lens in Example 7. Table 19 shows basic lens data for the zoom lens in Example 7, Table 20 shows data on the specifications of the zoom lens, and Table 21 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 18 shows aberration diagrams of the zoom lens, Fig. Figure 35 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 36 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 19] Example 7 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 358,57195 2,320 1,80100 34,97 0,58642 2 85,09780 7,200 1,49700 81,54 0,53748 3 -386,19076 0,200 4 72,25745 6,972 1,43875 94,94 0,53433 5 ∞ 0,200 6 69,93587 5,200 1,49700 81,54 0,53748 7 235,70554 DD[7] 8 96,21157 6,291 1,72047 34,71 0,58350 9 -43,59489 1,530 1,62230 53,17 0,55424 10 24,59706 5,600 11 -73,29120 1,410 1,49700 81,54 0,53748 12 27,09637 4,000 1,84661 23,88 0,62072 13 123,98633 2,799 14 -30,96977 1,200 1,91082 35,25 0,58224 15 353,74684 DD

[15] 16 -406,80952 2,850 1,80100 34,97 0,58642 17 -43,60631 0,100 18 74,86402 4,260 1,61800 63,33 0,54414 19 -43,68363 1,170 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 28,04424 7,050 1,49700 81,54 0,53748 23 -59,60296 0,150 24 34,77250 2,570 1,65412 39,68 0,57378 25 89,21437 1,800 26 -51,39895 1,110 1,90366 31,31 0,59481 27 24,25217 5,266 1,49700 81,54 0,53748 28 -60,88125 2,800 29 733,80887 3,771 1,80518 25,42 0,61616 30 -23,29690 0,950 1,58913 61,13 0,54067 31 39,10301 2,801 32 -39,71546 1,000 1,80100 34,97 0,58642 33 62,34880 4,199 34 54,23606 5,285 1,80000 29,84 0,60178 35 -37,12789 4,367 36 51,75623 6,461 1,48749 70,24 0,53007 37 -25,77385 1,310 1,80518 25,42 0,61616 38 -86,83396 4,400 39 -27,43970 1,260 1,91082 35,25 0,58224 40 -40,98080 25,514 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 20] Example 7 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,516 92,222 135,965 Bf' 29,393 29,393 29,393 FNo. 2,88 2,89 2,88 2ω[°] 30,6 17,0 11,6 [Table 21] Example 7 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,191 22,931 32,107 DD

[15] 14,409 8,821 2,687 DD

[20] 29,090 12,939 9,896

[0081] The following describes a zoom lens from Example 8. The zoom lens from Example 8 has a five-group configuration, which, starting from the object side, consists of a first lens group G1 with a positive refractive power, a second lens group G2 with a negative refractive power, a third lens group G3 with a negative refractive power, a fourth lens group G4 (the mp lens group) with a positive refractive power, and a fifth lens group G5 (the furthest rear lens group) with a positive refractive power. Fig.Figure 8 is a sectional view illustrating the lens configuration of the zoom lens in Example 8. Table 22 shows basic lens data for the zoom lens in Example 8, Table 23 shows data on the specifications of the zoom lens, and Table 24 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 19 shows aberration diagrams of the zoom lens, Fig. Figure 37 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 38 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 22] Example 8 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 303,47850 2,390 1,80100 34,97 0,58642 2 75,71759 7,850 1,49700 81,54 0,53748 3 -338,62836 0,200 4 67,27723 6,600 1,43875 94,94 0,53433 5 706,55071 0,200 6 67,16666 4,950 1,49700 81,54 0,53748 7 287,46150 DD[7] 8 98,18370 5,710 1,72047 34,71 0,58350 9 -49,05401 1,550 1,62230 53,17 0,55424 10 24,62771 DD

[10] 11 -75,51985 1,260 1,49700 81,54 0,53748 12 25,58057 5,388 1,84661 23,88 0,62072 13 106,72525 3,704 14 -31,24101 1,250 1,91082 35,25 0,58224 15 268,03486 DD

[15] 16 -521,95122 2,950 1,80100 34,97 0,58642 17 -44,70833 0,100 18 73,37158 4,310 1,61800 63,33 0,54414 19 -43,22381 1,150 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 27,81729 6,868 1,49700 81,54 0,53748 23 -57,84476 0,150 24 34,09999 2,550 1,65412 39,68 0,57378 25 102,68991 1,610 26 -54,83237 1,210 1,90366 31,31 0,59481 27 23,14151 5,662 1,49700 81,54 0,53748 28 -87,93105 2,500 29 372,91281 3,771 1,80518 25,42 0,61616 30 -24,31863 0,950 1,58913 61,13 0,54067 31 36,29877 3,256 32 -44,08151 1,050 1,80100 34,97 0,58642 33 60,80519 3,831 34 50,53032 5,748 1,80000 29,84 0,60178 35 -39,43779 4,000 36 48,86127 8,012 1,48749 70,24 0,53007 37 -26,40743 1,310 1,80518 25,42 0,61616 38 -86,68447 3,157 39 -27,70770 1,310 1,91082 35,25 0,58224 40 -44,10429 24,901 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 23] Example 8 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,514 92,218 135,960 Bf' 28,781 28,781 28,781 FNo. 2,88 2,89 2,88 2ω[°] 30,4 17,0 11,6 [Table 24] Example 8 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,199 20,933 29,242 DD

[10] 6,235 6,638 6,783 DD

[15] 14,153 8,593 2,488 DD

[20] 26,710 12,132 9,785

[0082] The following describes a zoom lens from Example 9. The zoom lens from Example 9 has a lens group configuration similar to that of the zoom lens from Example 8. Fig. Figure 9 is a sectional view illustrating the lens configuration of the zoom lens in Example 9. Table 25 shows basic lens data for the zoom lens in Example 9, Table 26 shows data on the specifications of the zoom lens, and Table 27 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 20 shows aberration diagrams of the zoom lens, Fig. Figure 39 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 40 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 25] Example 9 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 257,91881 2,390 1,83400 37,16 0,57759 2 73,18612 7,850 1,49700 81,54 0,53748 3 -329,42308 0,200 4 62,30117 6,600 1,43700 95,10 0,53364 5 849,43043 0,200 6 72,87230 4,950 1,49700 81,54 0,53748 7 263,78540 DD[7] 8 107,78333 5,710 1,72047 34,71 0,58350 9 -47,76821 1,550 1,62230 53,17 0,55424 10 25,18309 5,631 11 -93,23488 1,260 1,49700 81,54 0,53748 12 26,34063 3,999 1,84661 23,88 0,62072 13 99,67576 DD

[13] 14 -31,09640 1,250 1,91082 35,25 0,58224 15 318,83279 DD

[15] 16 -974,57258 2,950 1,80100 34,97 0,58642 17 -43,76266 0,100 18 65,14269 4,310 1,53775 74,70 0,53936 19 -49,97731 1,150 1,80518 25,42 0,61616 20 ∞ DD

[20] 21 (aperture) ∞ 1,300 22 28,69392 7,001 1,49700 81,54 0,53748 23 -59,87797 0,150 24 34,09590 2,550 1,65412 39,68 0,57378 25 85,63948 1,610 26 -54,93056 1,210 1,90366 31,31 0,59481 27 24,95033 6,359 1,49700 81,54 0,53748 28 -76,31225 2,500 29 141,63653 3,771 1,80518 25,42 0,61616 30 -23,83965 0,950 1,58913 61,13 0,54067 31 30,73799 2,499 32 -37,50492 1,050 1,80100 34,97 0,58642 33 53,05759 2,617 34 55,65453 6,802 1,83400 37,16 0,57759 35 -41,09507 4,001 36 52,54294 6,611 1,48749 70,24 0,53007 37 -38,16059 1,310 1,80518 25,42 0,61616 38 -57,00236 3,270 39 -28,19030 1,310 1,91082 35,25 0,58224 40 -47,93144 28,451 41 ∞ 2,850 1,51633 64,14 0,53531 42 ∞ [Table 26] Example 9 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,526 92,240 135,992 Bf' 32,332 32,332 32,332 FNo. 2,88 2,89 2,88 2ω[°] 30,4 17,0 11,6 [Table 27] Example 9 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,199 21,287 29,769 DD

[13] 4,000 4,585 4,348 DD

[15] 14,542 8,794 2,472 DD

[20] 26,846 11,921 9,998

[0083] The following describes a zoom lens from Example 10. The zoom lens from Example 10 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 10 is a sectional view illustrating the lens configuration of the zoom lens in Example 10. Table 28 shows basic lens data for the zoom lens in Example 10, Table 29 shows data on the specifications of the zoom lens, and Table 30 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 21 shows aberration diagrams of the zoom lens. Fig. Figure 41 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 42 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 28] Example 10 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 206,18300 2,390 1,80100 34,97 0,58642 2 77,37033 7,850 1,43875 94,94 0,53433 3 -468,12933 0,200 4 68,18946 6,600 1,43875 94,94 0,53433 5 665,76128 0,200 6 75,70042 4,950 1,49700 81,54 0,53748 7 318,83987 DD[7] 8 97,24407 5,710 1,72047 34,71 0,58350 9 -43,72645 1,550 1,62230 53,17 0,55424 10 24,36854 5,706 11 -73,08228 1,260 1,49700 81,54 0,53748 12 25,31089 4,204 1,84661 23,88 0,62072 13 107,97061 2,799 14 -30,56048 1,250 1,91082 35,25 0,58224 15 253,08206 DD

[15] 16 -16125,23228 2,950 1,80100 34,97 0,58642 17 -40,12049 0,100 18 80,78359 4,310 1,59282 68,62 0,54414 19 -40,99835 1,150 1,84666 23,78 0,62054 20 -145,20798 7,757 21 -92,18977 1,500 1,80000 29,84 0,60178 22 -254,53436 DD

[22] 23 (aperture) ∞ 1,300 24 27,68095 7,001 1,49700 81,54 0,53748 25 -56,35341 0,150 26 32,42093 2,550 1,65412 39,68 0,57378 27 119,28847 1,610 28 -55,80214 1,210 1,90366 31,31 0,59481 29 23,16845 6,126 1,49700 81,54 0,53748 30 -90,54469 2,500 31 590,71987 3,771 1,80518 25,42 0,61616 32 -24,23391 0,950 1,58913 61,13 0,54067 33 37,50164 3,358 34 -43,90672 1,050 1,80100 34,97 0,58642 35 57,93149 4,715 36 51,33459 5,893 1,80000 29,84 0,60178 37 -38,45068 1,953 38 50,11025 7,136 1,48749 70,24 0,53007 39 -28,43175 1,310 1,80518 25,42 0,61616 40 -83,91857 4,329 41 -26,99010 1,310 1,91082 35,25 0,58224 42 -47,11637 24,016 43 ∞ 2,850 1,51633 64,14 0,53531 44 ∞ [Table 29] Example 10 - Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,519 92,228 135,974 Bf' 27,894 27,894 27,894 FNo. 2,87 2,87 2,88 2ω[°] 30,4 17,0 11,6 [Table 30] Example 10 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,279 23,274 32,917 DD

[15] 11,721 7,221 2,117 DD

[22] 23,835 6,340 1,801

[0084] The following describes a zoom lens from Example 11. The zoom lens from Example 11 has a lens group configuration similar to that of the zoom lens from Example 1. Fig. Figure 11 is a sectional view illustrating the lens configuration of the zoom lens in Example 11. Table 31 shows basic lens data for the zoom lens in Example 11, Table 32 shows data on the specifications of the zoom lens, and Table 33 shows data on the distances between moving surfaces of the zoom lens. Fig. Figure 22 shows aberration diagrams of the zoom lens. Fig. Figure 43 shows lateral aberration diagrams of the zoom lens without image stabilization and Fig. Figure 44 shows lateral aberration diagrams of the zoom lens with image stabilization. [Table 31] Example 11 - Lens data Surface No. radius of curvature Surface distance and vd θgF 1 180,37474 2,390 1,80100 34,97 0,58642 2 69,14868 7,850 1,49700 81,54 0,53748 3 -481,66507 0,200 4 60,15068 7,500 1,43875 94,94 0,53433 5 1142,76498 0,200 6 76,86117 4,500 1,49700 81,54 0,53748 7 187,53228 DD[7] 8 111,60159 5,710 1,72047 34,71 0,58350 9 -39,89381 1,550 1,62230 53,17 0,55424 10 24,07077 4,980 11 -64,75230 1,260 1,49700 81,54 0,53748 12 24,25512 5,408 1,84661 23,88 0,62072 13 94,37171 2,799 14 -28,39083 1,250 1,91082 35,25 0,58224 15 193,35819 DD

[15] 16 -2763,02905 2,950 1,80100 34,97 0,58642 17 -42,42344 0,100 18 118,96564 4,310 1,59282 68,62 0,54414 19 -37,94715 1,150 1,84666 23,78 0,62054 20 -229,69252 7,412 21 389,16162 2,200 1,68893 31,07 0,60041 22 -215,34129 DD

[22] 23 (aperture) ∞ 1,300 24 27,53581 7,001 1,49700 81,54 0,53748 25 -57,95147 0,150 26 36,50795 2,550 1,65412 39,68 0,57378 27 105,69164 1,610 28 -54,28866 1,210 1,90366 31,31 0,59481 29 22,84035 6,968 1,49700 81,54 0,53748 30 -80,66013 2,500 31 381,31349 3,771 1,80518 25,42 0,61616 32 -25,25989 0,950 1,58913 61,13 0,54067 33 39,74943 3,501 34 -39,07424 1,050 1,80100 34,97 0,58642 35 67,59646 4,073 36 53,40416 5,837 1,80000 29,84 0,60178 37 -38,04851 4,001 38 47,49724 6,893 1,48749 70,24 0,53007 39 -27,13146 1,310 1,80518 25,42 0,61616 40 -85,37597 3,001 41 -29,19153 1,310 1,91082 35,25 0,58224 42 -47,66122 25,665 43 ∞ 2,850 1,51633 64,14 0,53531 44 ∞ [Table 32] Example 1 1- Specifications (d-line) Wide-angle end center End of phone Zoom magnification 1,0 1,8 2,6 f' 51,511 92,212 135,951 Bf' 29,545 29,545 29,545 FNo. 2,88 2,89 2,88 2ω[°] 30,6 17,0 11,6 [Table 33] Example 11 - Distances with respect to zoom Wide-angle end center End of phone DD[7] 1,697 21,960 30,401 DD

[15] 10,593 6,211 1,452 DD

[22] 21,360 5,480 1,796

[0085] Table 34 shows values ​​for the zoom lenses of Examples 1 to 11 that correspond to the condition formulas (1) to (6). In all examples, the d-line is used as a reference wavelength, and the values ​​shown in Table 34 below are with respect to the reference wavelength. [Table 34] Nr. Conditional expression Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 (1) vdBn 81,54 74,70 94,94 67,74 81,54 81,54 (2) θgFB n+0.00162vdB n-0.6415 0,0281 0,0189 0,0466 0,0125 0,0281 0,0281 (3) vd1p 86,01 81,03 82,52 90,47 86,01 86,01 (4) vdCp 63,33 70,24 60,29 81,54 63,33 63,33 (5) vd1n 34,97 31,31 40,14 33,27 34,97 34,97 (6) vd1m 94,94 91,31 91,31 94,94 94,94 94,94 Nr. Conditional expression Example 7 Example 8 Example 9 Example 10 Example 11 (1) vdBn 81,54 81,54 81,54 81,54 81,54 (2) θgFBn+0,00162vdBn-0,6415 0,0281 0,0281 0,0281 0,0281 0,0281 (3) vd1p 86,01 86,01 86,06 90,47 86,01 (4) vdCp 63,33 63,33 74,70 68,62 68,62 (5) vd1n 34,97 34,97 37,16 34,97 34,97 (6) vd1m 94,94 94,94 95,10 94,94 94,94

[0086] As can be seen from the data described above, each of the zoom lenses of examples 1 to 11 satisfies the condition expressions (1) to (6) and is a telephoto zoom lens with an angle of view of approximately 10 to 13 degrees at the telephoto end, a zoom ratio of approximately 2.4 to 3.1, a large aperture with a maximum aperture of approximately F2.8 over the entire zoom range and successfully suppressed primary chromatic aberration and secondary chromatic aberration.

[0087] An embodiment of an imaging device according to the invention is described below with reference to Fig. 45 and Fig. 46 described. Fig. 45 and Fig.Figures 46 are perspective views, each showing the front and back of a camera 30. The camera 30 is a non-reflective digital camera to which an interchangeable lens 20 is detachably attached, the lens being a zoom lens 1 according to the embodiment of the invention, which is housed in a lens tube.

[0088] The camera 30 comprises a camera body 31, and a shutter release button 32 and a power button 33 are located on the top of the camera body 31. Operating sections 34 and 35 and a display section 36 are located on the rear of the camera body 31. The display section 36 shows a captured image and an image within the field of view before an imaging operation is performed.

[0089] An imaging aperture, through which light from the subject enters, is formed at the center of the front of the camera body 31, and a mounting bracket 37 is arranged at the position corresponding to the imaging aperture. The interchangeable lens 20 is attached to the camera body 31 by means of the mounting bracket 37.

[0090] The camera body 31 contains an image sensor (not shown), such as a CCD, for receiving a subject image formed by the interchangeable lens 20 and for outputting an image signal corresponding to the subject image; a signal processing circuit for processing the image signal output by the image sensor to generate an image; a storage medium for saving the generated image; etc. With this camera 30, a still image or a moving image can be captured when the shutter release button 32 is pressed, and the image data obtained by the imaging operation is stored in the storage medium.

[0091] The camera 30 of this embodiment, which is equipped with the zoom lens 1 according to the invention, allows the acquisition of high-quality images with reduced primary chromatic aberration and secondary chromatic aberration.

[0092] The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the embodiments and examples described above, and various modifications can be made to the invention. For example, the values ​​of the radius of curvature, the surface distance, the refractive index, the Abbe number, the aspheric coefficients, etc., of each lens are not limited to the values ​​shown in the examples described above and can assume other values.

[0093] While the embodiment of the imaging device is described and shown in the drawings as an example of a non-reflective (so-called mirrorless) digital camera, this is not intended to limit the imaging device according to the invention. For example, the invention is also applicable to imaging devices such as video cameras, digital cameras, cinema cameras, and broadcast cameras.

Claims

[1] Zoom lens consisting as a whole of four or five lens groups, which, starting from one side of the object, comprise a first lens group (G1) with a positive refractive power, a second lens group (G2) with a negative refractive power, one or two intermediate lens groups comprising an mp lens group with a positive refractive power, and a rearmost lens group located at the image-side position of the entire system and having a positive refractive power, where a change in magnification is achieved by changing all distances between the adjacent lens groups, an A-cement lens (CA), consisting of a positive lens and a negative lens cemented together in this order starting from the object side, is arranged at the object-side position of the second lens group (G2), a B-cement lens (CB), consisting of a positive lens and a negative lens, is arranged on the image side of the A-cement lens (CA) and on the object side of the mp-lens group, a C-cement lens (CC), consisting of a positive lens and a negative lens, arranged in the mp lens group, and the following conditional expressions (1) and (2) are satisfied: 60<νdBn 0.0055<θgFBn+0.00162νdBn−0.6415<0.050 where vdBn is an Abbe number of the negative lens forming the B-cement lens (CB) and θgFBn is a partial dispersion ratio of the negative lens forming the B-cement lens (CB). [2] Zoom lens according to claim 1, wherein the first lens group (G1) or the rearmost lens group is fixed during the magnification change relative to an imaging plane. [3] Zoom lens according to one of claims 1 or 2, wherein the first lens group (G1) comprises at least two positive lenses, and the following condition expression (3) is satisfied: 80.5<νd1p where vd1p is an average Abbe number of positive lenses in the first lens group (G1). [4] Zoom lens according to one of claims 1 to 3, wherein the following condition expression (4) is satisfied: 57<νdCp where vdCp is an abbreviation of the positive lens forming the C cement lens (CC). [5] Zoom lens according to one of claims 1 to 4, wherein focusing from an object at infinity to a next object is effected by moving only the entire mp lens group or a part of the lenses forming the mp lens group along the optical axis (Z). [6] Zoom lens according to any one of claims 1 to 5, wherein the mp lens group comprises the C cement lens (CC) and a positive lens. [7] Zoom lens according to any one of claims 1 to 6, wherein the first lens group (G1) comprises at least one negative lens satisfying the following condition expression (5): 28<νd1n<45 where vd1n is an Abbe number of the negative lens in the first lens group (G1). [8] Zoom lens according to any one of claims 1 to 7, wherein The most posterior lens group, in order starting from the object side, consists of an anterior group with a positive refractive power, a medial group with a negative refractive power and a posterior group with a positive refractive power. the anterior group consists of three positive lenses and one negative lens, and Image stabilization is achieved by moving only the center group in directions perpendicular to the direction of the optical axis (Z). [9] Zoom lens according to claim 8, wherein the center group consists of two negative lenses and one positive lens. [10] Zoom lens according to any one of claims 1 to 9, comprising four lens groups which, starting from the object side, consist of the first lens group (G1), the second lens group (G2), the mp lens group and the rearmost lens group, or comprising five lens groups which, starting from the object side, consist of the first lens group (G1), the second lens group (G2), a lens group with a negative refractive power, the mp lens group and the rearmost lens group. [11] Zoom lens according to any one of claims 1 to 10, wherein the second lens group (G2) comprises two or more positive lenses and two or more negative lenses. [12] Zoom lens according to any one of claims 1 to 11, wherein the first lens group (G1), starting from the object side, consists of a negative lens, a positive lens, a positive lens and a positive lens. [13] Zoom lens according to one of claims 1 to 12, wherein the first lens group (G1) comprises at least one positive lens and the following condition expression (6) is satisfied: 83<νd1m where vd1m is the largest Abbe number of at least one positive lens in the first lens group (G1). [14] Zoom lens according to any one of claims 1 to 13, wherein the first lens group (G1) comprises at least one positive lens, and the positive lens with the highest Abbe number in the first lens group (G1) is a single lens. [15] Imaging device comprising the zoom lens (1) according to any one of claims 1 to 14.

Images