Optical system and imaging device

Abstract

To reduce the size and weight of a movable group that is eccentric to an optical axis, and prevent the occurrence of chromatic aberration caused by the movable group.SOLUTION: An optical system 1a is composed of a plurality of lens groups L1-L7, and any of the lens groups has a movable group IS movable in a direction eccentric to an optical axis. The movable group includes a cemented lens obtained by joining a resin layer rep having a refractive power and a base material lens to each other. When the focal distance of the resin layer is fr, and the focal distance of the movable group is fis, the condition of -0.95≤fis / fr<0 is satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical system having a movable group that can move in a direction eccentric with respect to the optical axis.

Background Art

[0002] In an optical system used in an imaging device, by moving (shifting) a lens or a lens group as an anti-shake group in a direction eccentric with respect to the optical axis, it is possible to reduce (correct) image blur caused by shake of the imaging device due to hand shake or the like. Patent Documents 1 and 2 disclose optical systems in which a part of an intermediate lens group is shifted as an anti-shake group in a direction orthogonal to the optical axis. Specifically, Patent Document 1 discloses a positive lead type zoom lens having first to fifth lens groups as positive, negative, positive, negative, and positive lens groups arranged in order from the object side to the image side, and an optical system in which the entire third lens group is used as an anti-shake group. Further, Patent Document 2 discloses a positive lead type zoom lens having first to seventh lens groups as positive, negative, positive, negative, positive, negative, and positive lens groups arranged in order from the object side to the image side, and an optical system in which the entire fourth lens group composed of a cemented lens in which two negative lenses are cemented is used as an anti-shake group.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the optical system disclosed in Patent Document 1, the third lens group, which is an anti-shake group, is composed of four lenses, positive, negative, positive, and negative, arranged in order from the object side, and has a large weight. For this reason, the drive mechanism for shifting the entire third lens group with respect to the optical axis becomes large, and as a result, the lens barrel that houses the imaging optical system becomes large. Further, in the imaging optical system disclosed in Patent Document 2, although the fourth lens group, which is an anti-shake group, is composed of two lenses and is small and lightweight, it is difficult to suppress the occurrence of chromatic aberration in a state where the fourth lens group is shifted.

[0005] The present invention provides an optical system and an imaging device that can reduce the size and weight of a movable group that is eccentric with respect to the optical axis and can also suppress the occurrence of chromatic aberration caused by the movable group.

Means for Solving the Problems

[0006] The optical system according to one aspect of the present invention includes a plurality of lens groups, and any one of the plurality of lens groups has It consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with negative refractive power, which are arranged in order from the object side to the image side. During zooming, the distance between adjacent lens groups changes, a movable group that is movable in a direction eccentric with respect to the optical axis. The movable group includes a cemented lens in which a resin layer having a refractive power and a base lens are cemented. The movable group is included in the second lens group. When the focal length of the resin layer is fr and the focal length of the movable group is fis, -0.95 ≦ fis / fr < 0 It is characterized by satisfying the following conditions. An imaging device having the above optical system also constitutes another aspect of the present invention.

Effects of the Invention

[0007] According to the present invention, it is possible to reduce the size and weight of a movable group that is eccentric with respect to the optical axis and also suppress the occurrence of chromatic aberration caused by the movable group.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0010] First, prior to the description of specific embodiments, matters common to each embodiment will be described. The optical system of each embodiment has a plurality of lens groups. In each embodiment, the lens group is composed of a single lens or a plurality of lenses. The interval between adjacent lens groups changes during at least one of zooming and focusing. Any one of the lens groups is an anti-shake group that moves (shifts) in a direction (eccentric direction) including a component perpendicular to the optical axis to reduce (correct) image blur. The anti-shake group includes a cemented lens in which a resin layer having a refractive power and a base lens are joined (adhered).

[0011] Note that the anti-shake group may rotate around a rotation center on the optical axis in a direction including a component perpendicular to the optical axis. That is, the anti-shake group may move in a direction eccentric with respect to the optical axis. Also, in each embodiment, the case of moving the movable group to correct image blur will be described, but the movable group may be moved for purposes other than image blur correction, such as panning shooting or following a moving object during moving object imaging.

[0012] The optical systems of Examples 1 to 3 and Example 5 are zoom lenses with a variable focal length, and the optical system of Example 4 is a single-focus lens with a fixed focal length. In the zoom lens, the lens groups are a group of one or more lenses that move integrally during zooming (changing the magnification) between the wide-angle end and the telephoto end. That is, the distance between adjacent lens groups changes during zooming. The lens group may include an aperture stop. Also, the wide-angle end and the telephoto end respectively indicate the zoom states of the maximum picture angle (minimum focal length) and the minimum picture angle (maximum focal length) when the lens group that moves during zooming is located at both ends of the range where it can move mechanically or controllably on the optical axis. In the single-focus lens, a group of lenses separated before and after the aperture stop, a group of lenses that move like an anti-shake group, and a group of lenses separated before and after that are each regarded as a lens group. Specific numerical examples 1 to 5 corresponding to each of Examples 1 to 5 will be described later.

[0013] Figures 1, 5, 9, and 17 respectively show cross-sections of the zoom lenses 1a, 1b, 1c, and 1d of Examples 1 to 3 and Example 5 in an infinitely focused state at the wide-angle end. The zoom ratio of the zoom lens 1a of Example 1 (numerical example 1) is 4.7 times, and the F-number is about 2.9. The half picture angle at the wide-angle end of the zoom lens 1a is 37 degrees, and the half picture angle at the telephoto end is 11 degrees. The zoom ratio of the zoom lens 1b of Example 2 (numerical example 2) is 4.7 times, and the F-number is about 2.9. The half picture angle at the wide-angle end of the zoom lens 1b is 37 degrees, and the half picture angle at the telephoto end is 11 degrees. The zoom ratio of the zoom lens 1c of Example 3 (numerical example 3) is 4.7 times, and the F-number is about 2.9. The half picture angle at the wide-angle end of the zoom lens 1c is 37 degrees, and the half picture angle at the telephoto end is 11 degrees. The zoom ratio of the zoom lens 1e of Example 5 (numerical example 5) is 3.8 times, and the F-number is about 4.6 to 7.3. The half picture angle at the wide-angle end of the zoom lens 1e is 12 degrees, and the half picture angle at the telephoto end is 3 degrees.

[0014] (A), (B), and (C) of FIGS. 2, 6, 10, and 18 respectively show the longitudinal aberrations of the wide-angle ends, intermediate zoom positions, and telephoto ends of the zoom lenses 1a, 1b, 1c, and 1d of Examples 1 to 3 and Example 5. (A), (B), and (C) of FIGS. 3, 7, 11, and 19 respectively show the lateral aberrations of the wide-angle ends, intermediate zoom positions, and telephoto ends of the zoom lenses 1a, 1b, 1c, and 1d. (A), (B), and (C) of FIGS. 4, 8, 12, and 20 respectively show the lateral aberrations in a state where the anti-vibration group is shifted to a position correcting an angular shake of 0.3 degrees at the wide-angle ends, intermediate zoom positions, and telephoto ends of the zoom lenses 1a, 1b, 1c, and 1d.

[0015] Further, FIG. 13 shows a cross-section of the single-focus lens of Example 4 in an infinitely focused state. The F-number of the single-focus lens 1d of Example 4 (numerical example 4) is about 1.45, and the semi-field angle is 15 degrees. FIGS. 13 and 14 respectively show the longitudinal aberration and the lateral aberration of the single-focus lens of Example 4. FIG. 15 shows the lateral aberration in a state where the anti-vibration group is shifted to a position correcting an angular shake of 0.3 degrees in the single-focus lens of Example 4.

[0016] The lenses 1a to 1e are used as an imaging optical system of an imaging device such as a digital camera, a video camera, a broadcast camera, a surveillance camera, and a silver halide film camera. Further, the lenses 1a to 1e can also be used as a projection optical system of an image projection device (projector).

[0017] In FIGS. 1, 5, 9, 13, and 17, the left side is the object side (front side), and the right side is the image side (rear side). Li (i = 1, 2, …) indicates the i-th lens group counted from the object side. IS indicates the anti-shake group. Grep indicates the resin layer. SP indicates the aperture stop (stop group). IP indicates the image plane. On the image plane IP, the imaging surface of a solid-state imaging device (photoelectric conversion element) such as a CCD sensor or a CMOS sensor or the film surface of a silver halide film is arranged. In FIGS. 1, 5, 9, and 17, the movement trajectories of the lens groups and the aperture stop SP during zooming from the wide-angle end to the telephoto end are indicated by arrows. The arrow marked with “FOCUS” indicates the moving direction of the lens group during focusing from an infinite object to a close object.

[0018] In the spherical aberration diagrams of FIGS. 2, 6, 6, 10, and 18, Fno indicates the F-number. The solid line indicates the spherical aberration for the d-line (wavelength 587.6 nm), and the two-dot chain line indicates the spherical aberration for the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line S indicates the sagittal image plane for the d-line, and the broken line M indicates the meridional image plane for the d-line. The distortion aberration diagram indicates the distortion aberration for the d-line. The chromatic aberration diagram indicates the lateral chromatic aberration for the g-line. ω is the semi-field angle (°).

[0019] Hereinafter, the lens configurations of each embodiment will be described.

[0020] The zoom lens 1a of Embodiment 1 shown in FIG. 1 is a seven-group zoom lens composed of, in order from the object side to the image side, a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a positive refractive power, a fourth lens group L4 with a positive refractive power, a fifth lens group L5 with a negative refractive power, a sixth lens group L6 with a negative refractive power, and a seventh lens group L7 with a positive refractive power.

[0021] When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the object side, and after the second lens group L2 moves toward the image side, it moves toward the object side. The third lens group L3 moves toward the object side, and the fourth lens group L4 moves toward the object side so that the distance between the third lens group L3 and the fourth lens group L4 becomes smaller. The fifth lens group L5 moves toward the object side so as to widen after the distance between the fifth lens group L5 and the fourth lens group L4 narrows. The sixth lens group L6 moves toward the object side and then toward the image side so that the distance between the sixth lens group L6 and the fifth lens group L5 widens. The seventh lens group L7, which is the final lens group, is stationary during zooming. The fifth lens group L5 moves during focusing. The aperture stop SP is disposed between the second lens group and the third lens group and is stationary during zooming.

[0022] In Example 1, an anti-vibration group IS having an overall negative refractive power is disposed on the most image side in the third lens group L3. The anti-vibration group IS is composed of a positive lens made of a resin layer Grep disposed in order from the object side to the image side and two elements of a negative lens as a base lens bonded to each other.

[0023] The zoom lens 1b of Example 2 shown in FIG. 5 is a seven-group zoom lens composed of, in order from the object side to the image side, a first lens group L1 having a positive refractive power, a second lens group L2 having a negative refractive power, a third lens group L3 having a positive refractive power, a fourth lens group L4 having a positive refractive power, a fifth lens group L5 having a negative refractive power, a sixth lens group L6 having a negative refractive power, and a seventh lens group L7 having a positive refractive power.

[0024] When zooming from the wide-angle end to the telephoto end, the first lens group L1 remains stationary, and the second lens group L2 moves toward the image side. The third lens group L3 moves toward the object side, and the fourth lens group L4 moves toward the object side so that the distance between the fourth lens group L4 and the third lens group L3 decreases. The fifth lens group L5 moves toward the object side so as to expand after the distance between the fifth lens group L5 and the fourth lens group L4 narrows. The sixth lens group L6 moves toward the object side and then toward the image side so that the distance between the sixth lens group L6 and the fifth lens group L5 expands. The seventh lens group, which is the final lens group, remains stationary during zooming. The fifth lens group L5 moves during focusing. The aperture stop SP is disposed between the second lens group and the third lens group and remains stationary during zooming.

[0025] In Example 2, an anti-vibration group IS having an overall negative refractive power is disposed on the most image-side of the third lens group L3. The anti-vibration group IS is composed of a positive lens made of a resin layer Grep arranged in order from the object side to the image side, a positive lens as a base lens, and three elements of a negative lens that are bonded to each other.

[0026] The zoom lens 1c of Example 3 shown in FIG. 9 is a seven-group zoom lens composed of, in order from the object side to the image side, a first lens group L1 having a positive refractive power, a second lens group L2 having a negative refractive power, a third lens group L3 having a positive refractive power, a fourth lens group L4 having a positive refractive power, a fifth lens group L5 having a negative refractive power, a sixth lens group L6 having a negative refractive power, and a seventh lens group L7 having a positive refractive power.

[0027] The movement of each lens group during zooming from the wide-angle end to the telephoto end and during focusing in Example 3 is the same as that of the zoom lens 1b of Example 2. Also in this example, the aperture stop SP is disposed between the second lens group and the third lens group and remains stationary during zooming.

[0028] In Example 3, the anti-vibration group IS is disposed second from the image side in the third lens group L3. The anti-vibration group IS is composed of a negative lens made of a resin layer Grep arranged in order from the object side to the image side and two elements of a negative lens as a base lens that are bonded to each other.

[0029] The single-focus lens 1d of Example 4 shown in FIG. 13 is a four-group lens composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in order from the object side to the image side. The aperture stop SP is arranged between the first lens group L1 and the second lens group L2. The second lens group L2 moves during focusing.

[0030] In Example 4, the entire third lens group L3 is used as the anti-vibration group IS. The third lens group L3 is composed of two elements, a positive lens made of a resin layer Grep and a negative lens as a base lens, which are adhered to each other and arranged in order from the object side to the image side.

[0031] The zoom lens 1e of Example 5 is a five-group zoom lens composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with negative refractive power, which are arranged in order from the object side to the image side.

[0032] During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the object side, and the second lens group L2 remains stationary. The third lens group L3 moves toward the object side, and the fourth lens group L4 moves toward the object side so as to spread after the distance between the fourth lens group L4 and the third lens group L3 decreases. The fifth lens group L5, which is the final lens group, moves toward the object side so as to slightly decrease after the distance between the fifth lens group L5 and the fourth lens group L4 increases. The fourth lens group L4 moves during focusing. The aperture stop SP is arranged on the most object-side in the second lens group L2.

[0033] In Example 5, an anti-vibration group IS with negative refractive power as a whole is arranged on the most object-side in the second lens group L2. The anti-vibration group IS is composed of three elements, a positive lens made of a resin layer Grep, a negative lens as a base lens, and a positive lens, which are adhered to each other and arranged in order from the object side to the image side.

[0034] As described above, in each embodiment, the anti-vibration group IS includes an optical element (bonded lens) in which a resin layer Grep as a lens and a base lens are bonded. Generally, the resin material has a lower specific gravity than glass, and using a resin layer in the anti-vibration group is advantageous for reducing the size and weight of the entire anti-vibration group. Also, by closely adhering the resin material to the base material to form an integral optical element, the configuration as an anti-vibration group is simplified, and it is possible to reduce the size of the entire lens system in the optical axis direction or reduce the weight of the anti-vibration unit including the anti-vibration group and the mechanism for driving it. In each embodiment, the refractive power of the resin layer Grep of the anti-vibration group IS is set to be positive or negative with a sign different from that of the refractive power of the entire anti-vibration group IS. This makes it possible to suppress axial chromatic aberration within the anti-vibration group IS due to the resin layer Grep and decentering chromatic aberration that occurs during shifting (when moving).

[0035] For the lenses 1a to 1e of each embodiment (numerical example), when the focal length of the resin layer Grep of the anti-vibration group IS is fr and the focal length of the anti-vibration group IS is fis, the following condition of formula (1) is satisfied. -0.95 ≦ fis / fr < 0 (1) Formula (1) shows the relationship between the focal length fr of the resin layer lens Grep and the focal length fis of the entire anti-vibration group IS for favorably correcting the decentering chromatic aberration and decentering coma aberration that occur when the anti-vibration group IS shifts with respect to the optical axis to correct image shake. The range of formula (1) is negative. This means that the focal length fr of the resin layer Grep with respect to the anti-vibration group IS must always have a different sign. This corrects the chromatic aberration as the anti-vibration group IS, and the decentering chromatic aberration and decentering coma aberration during shifting. If the focal length fis of the anti-vibration group IS is small such that fis / fr exceeds the upper limit value of formula (1), the refractive power of the anti-vibration group IS becomes too strong, making it difficult to sufficiently correct the decentering coma aberration and decentering field curvature aberration, which is not preferable. Also, if the focal length fr of the resin layer Grep is large such that fis / fr exceeds 0, which is the upper limit value of formula (1), it becomes difficult to suppress the chromatic aberration correction as the anti-vibration group IS, the decentering chromatic aberration, and the decentering coma aberration during shifting, which is not preferable.

[0036] On the one hand, if the focal length fis of the anti-shake group IS is large such that fis / fr is lower than the lower limit value of the formula (1), it is necessary to increase the shift amount of the anti-shake group IS for correcting image blur. For this reason, the anti-shake unit becomes large, which is not preferable. Further, since the shift amount of the anti-shake group IS becomes too large, higher-order decentered coma aberration and the like also become large, which is not preferable. On the other hand, if the focal length fr of the resin layer Grep is small such that fis / fr is lower than the lower limit value of the formula (1), the refractive power of the resin layer Grep becomes too strong and chromatic aberration and decentered chromatic aberration in the anti-shake group IS tend to become excessive, which is not preferable. Further, since the volume of the resin layer increases to ensure the refractive power of the resin layer Grep, it is not preferable from the viewpoint of weight reduction.

[0037] Note that it is more preferable if the numerical range of the formula (1) is as follows.

[0038] -0.50 ≦ fis / fr ≦ -0.01 (1a) Also, it is even more preferable if the numerical range of the formula (1) is as follows.

[0039] -0.30 ≦ fis / fr ≦ -0.05 (1b) Also, let the Abbe number of the resin layer Grep with respect to the d-line be νd_r, the refractive index of the resin layer Grep with respect to the d-line be nd_r, the thickness of the resin layer Grep on the optical axis be dr, and the thickness of the entire anti-vibration group IS on the optical axis be Dis. Let the lateral magnification of the anti-vibration group IS in the state where the focal length of the entire lens system (1a~1e) is maximum be βist, and the combined lateral magnification of all lens groups on the image side of the anti-vibration group IS in the same state be βrt. Let the radius of curvature of the lens surface on the object side of the anti-vibration group IS be R1, and the radius of curvature of the lens surface on the image side be R2. Let the maximum thickness in the optical axis direction within the effective diameter of the resin layer Grep be Dmax, and the minimum thickness be Dmin. Let the distance on the optical axis from the aperture stop SP to the lens surface on the object side of the anti-vibration group IS in the state where the focal length of the entire lens system is minimum be Dstpw, and the distance on the optical axis from the lens surface on the object side of the entire lens system to the image plane (total lens length) in the same state be OTDw. Let the focal length of the entire lens system at the telephoto end of the zoom lens (1a~1c, 1e) be ft, the average Abbe number of at least one lens other than the resin layer in the anti-vibration group IS with respect to the d-line be νd_gave, and the Abbe number of the resin layer Grep with respect to the d-line be νd_r. At this time, the lenses of each example preferably satisfy at least one of the conditions of the following formulas (2) to (10). 15≦νd_r≦40 (2) 1.50≦nd_r≦1.75 (3) 0.001≦dr / Dis≦0.850 (4) 0.1≦|(1-βist)βrt|≦5.0 (5) |(R2+R1) / (R2-R1)|≦2.0 (6) 1.1≦Dmax / Dmin≦30.0 (7) |Dstpw / OTDw|≦0.8 (8) 0.05≦|fis / ft|≦2.00 (9) 5.0≦|νd_gave-νd_r|≦60.0 (10) Equation (2) shows the condition regarding the Abbe number νd_r of the resin layer Grep for good chromatic aberration correction during the shift of the anti-vibration group IS. When νd_r exceeds the upper limit value of Equation (2), chromatic aberration correction in the anti-vibration group IS tends to be excessive. Also, when νd_r approaches the Abbe number of the base lens, the refractive powers of the base lens and the resin layer Grep tend to become strong, and as a result, the anti-vibration group IS becomes larger, which is not preferable.

[0040] On the other hand, when νd_r is below the lower limit value of Equation (2), although it is advantageous for the primary chromatic aberration correction of the anti-vibration group IS, the partial dispersion ratio ΘgF with respect to the g-line becomes large, making the secondary chromatic aberration correction difficult. Also, since it is difficult for the resin material to have an Abbe number below the lower limit of Equation (2), it is not preferable.

[0041] Equation (3) shows the condition regarding the refractive index nd_r of the resin layer Grep for achieving both suppression of decentered coma aberration during the shift of the anti-vibration group IS and weight reduction of the anti-vibration group IS. When nd_r exceeds the upper limit value of Equation (3), it is advantageous for the weight reduction of the anti-vibration group IS. However, since the refractive index nd_r of the resin layer Grep is too high, when the surface accuracy of the resin layer deviates from the design value due to manufacturing errors, etc., the deterioration of optical performance such as coma aberration becomes too large, which is not preferable. Also, it is difficult to obtain a refractive index exceeding the upper limit value of Equation (3) as a resin material.

[0042] On the other hand, when nd_r is below the lower limit value of Equation (3), the volume of the resin layer Grep becomes large, which is not preferable from the perspective of miniaturization and weight reduction. Also, when the refractive index of the resin material becomes small, the Abbe number νd_r tends to become large, and the degree of freedom in selecting the glass of the base lens is limited from the perspective of chromatic aberration correction in the anti-vibration group IS, which is not preferable. Furthermore, it is difficult to obtain a refractive index below the lower limit value of Equation (3) as a resin material.

[0043] Equation (4) shows the conditions regarding the thickness dr of the resin layer Grep and the overall thickness Dis of the anti-vibration group IS in order to achieve both weight reduction of the anti-vibration group IS and suppression of various aberrations during shifting. If the thickness of the resin layer Grep is so large that dr / Dis exceeds the upper limit value of Equation (4), it becomes difficult to miniaturize and lighten the anti-vibration group IS, which is not preferable. Also, if the thickness of the anti-vibration group IS is so small that dr / Dis exceeds the upper limit value of Equation (4), the thickness of the resin layer Grep relatively increases, and the formability of the highly precise resin surface in manufacturing the resin layer Grep tends to decrease, which is not preferable.

[0044] On the other hand, if the thickness of the resin layer Grep is small such that dr / Dis is below the lower limit value of Equation (4), it is advantageous from the perspective of miniaturizing and lightening the anti-vibration group IS. However, when the resin layer Grep becomes a positive lens, it becomes difficult to make the refractive power sufficiently large. As a result, chromatic aberration correction during shifting cannot be sufficiently performed, which is not preferable. Furthermore, when the resin layer Grep becomes a negative lens, in order to sufficiently correct decentering aberration, it is necessary to increase the decentering ratio, which is the ratio of the thickness on the optical axis to the thickness near the effective diameter. This is not preferable from the perspective of formability. Also, if the thickness of the resin layer Grep is large such that dr / Dis exceeds the upper limit value of Equation (4), the overall volume of the anti-vibration group IS increases, which is not preferable from the perspective of miniaturization and weight reduction. Moreover, if the thickness of the anti-vibration group IS is small such that dr / Dis exceeds the upper limit value of Equation (4), the thickness of the resin layer Grep relatively increases, and the formability of the highly precise resin surface in manufacturing the resin layer Grep tends to decrease, which is not preferable.

[0045] Equation (5) shows the conditions regarding the relationship between the lateral magnification βist of the anti-vibration group IS and the combined lateral magnification βrt of all the lens groups on the image side with respect to the anti-vibration group IS in order to achieve both ensuring the image blur correction performance of the anti-vibration group IS and miniaturization and weight reduction. Here, the lateral magnification βist and the combined lateral magnification βrt are the values at the telephoto end in the zoom lens. |(1 - βist)βrt| in Equation (5) indicates the ratio of the shift amount of the image on the image plane to the shift amount of the anti-vibration group IS, that is, the so-called decentering sensitivity.

[0046] If the lateral magnification of the anti-vibration group IS is large such that |(1 - βist)βrt| exceeds the upper limit value of Equation (5), the shift amount of the anti-vibration group IS can be suppressed, which is advantageous for miniaturizing the anti-vibration unit. However, if the eccentricity sensitivity is too large and the anti-vibration group IS shifts from the optical axis due to manufacturing errors or the like in a situation where image blur does not occur, eccentricity coma aberration or the like will occur, which is not preferable. Also, since mechanical control of the shift amount of the anti-vibration group IS becomes difficult, it is not preferable.

[0047] On the other hand, if the lateral magnification of the anti-vibration group IS is small such that |(1 - βist)βrt| is below the lower limit value of Equation (5), it is necessary to increase the shift amount of the anti-vibration group IS in order to obtain a sufficient correction amount (correction angle) for image blur. As a result, the anti-vibration unit becomes larger, which is not preferable.

[0048] Equation (6) shows the conditions regarding the ratio of the radii of curvature R1 and R2 of the lens surfaces on the object side and the image side of the anti-vibration group IS that are the most object-side and the most image-side, which is the so-called shape factor, for correcting the eccentricity aberration during the shift of the anti-vibration group IS. If |(R2 + R1) / (R2 - R1)| exceeds the upper limit value of Equation (6), the shape of the entire anti-vibration group IS becomes a meniscus shape, making it difficult to suppress the eccentricity coma aberration during the shift, which is not preferable.

[0049] Equation (7) shows the conditions regarding the ratio of the maximum thickness Dmax and the minimum thickness Dmin in the optical axis direction of the resin layer Grep, which is the so-called thickness ratio deviation, in order to achieve both weight reduction of the anti-vibration group IS and suppression of various aberrations during the shift. Both the maximum thickness Dmax and the minimum thickness Dmin are obtained from the range within the effective lens diameter of the resin layer Grep. If Dmax / Dmin exceeds the upper limit value of Equation (7), although it is advantageous for correcting the eccentricity aberration of the anti-vibration group IS, the moldability decreases, which is not preferable from the manufacturing perspective. Also, if the thickness ratio deviation is large, the volume of the resin layer Grep tends to be large, which is not preferable from the perspective of weight reduction. On the other hand, if Dmax / Dmin is below the lower limit value of Equation (7), it becomes difficult to sufficiently correct the eccentricity aberration during the shift of the anti-vibration group IS, which is not preferable.

[0050] Equation (8) shows the condition regarding the relationship between the distance Dstpw from the aperture stop SP to the lens surface closest to the object side of the image stabilization group IS and the overall lens length OTDw in order to suppress the occurrence of various aberrations during the shift of the image stabilization group IS. Here, the distance Dstpw and the overall lens length OTDw are the values at the wide-angle end in the zoom lens. If |Dstpw / OTDw| exceeds the upper limit value of Equation (8), the distance Dstpw from the aperture stop SP to the image stabilization group IS becomes large, and it becomes difficult to suppress the field curvature during the shift of the image stabilization group IS, which is not preferable.

[0051] Equation (9) shows the condition regarding the relationship between the focal length ft of the entire lens system and the focal length fis of the image stabilization group IS in order to achieve both suppression of various aberrations during the shift of the image stabilization group IS and reduction of the size and weight of the image stabilization group IS. Here, the overall system focal length ft is the focal length at the telephoto end in the zoom lens. If the focal length of the image stabilization group IS is large such that |fis / ft| exceeds the upper limit value of Equation (9), it is necessary to increase the shift amount of the image stabilization group IS, which is not preferable from the perspective of size and weight reduction. Also, if the overall system focal length is small such that |fis / ft| exceeds the upper limit value of Equation (9), the zoom ratio in the zoom lens becomes small, which is not preferable.

[0052] On the other hand, if the focal length of the image stabilization group IS is small such that |fis / ft| is below the lower limit value of Equation (9), the shift amount of the image stabilization group IS can be suppressed. However, the refractive power of the image stabilization group IS is too strong, and it becomes difficult to correct various aberrations such as various aberrations in the state where the image stabilization group IS is not shifted and decentered coma aberration during the shift, which is not preferable. Also, if the overall system focal length is large such that |fis / ft| is below the lower limit value of Equation (9), it becomes difficult to suppress axial chromatic aberration, etc. at the telephoto end, which is not preferable.

[0053] Equation (10) shows the condition regarding the difference between the average Abbe number νd_gave of the lenses other than the resin layer of the anti-vibration group IS and the Abbe number νd_r of the resin layer Grep in order to correct the axial chromatic aberration generated in the anti-vibration group IS and the decentering chromatic aberration generated during the shift of the anti-vibration group IS well. When this difference exceeds the upper limit value of Equation (10), the chromatic aberration generated in the anti-vibration group IS can be suppressed. However, the refractive power difference between the resin layer Grep and the base lens becomes small, and as a result, it becomes difficult to suppress spherical aberration and coma aberration in the state where the anti-vibration group IS has not shifted, which is not preferable.

[0054] On the other hand, when the above difference is below the lower limit value of Equation (10), it is necessary to increase the refractive power difference between the resin layer Grep and the base lens in order to suppress chromatic aberration well. As a result, it becomes difficult to suppress decentering coma aberration during the shift of the anti-vibration group IS, which is not preferable. Also, when the above difference is below the lower limit value of Equation (10), it becomes difficult to correct the chromatic aberration itself in the anti-vibration group IS, which is not preferable.

[0055] It is more preferable to set the numerical ranges of the above Equations (2) to (10) as follows. Some modifications were made in relation to the numerical values in Table 1.

[0056] 20 ≦ νd_r ≦ 40 (2a) 1.50 ≦ nd_r ≦ 1.70 (3a) 0.005 ≦ dr / Dis ≦ 0.600 (4a) 0.2 ≦ |(1 - βist)βrt| ≦ 4.0 (5a) |(R2 + R1) / (R2 - R1)| ≦ 1.7 (6a) 1.5 ≦ Dmax / Dmin ≦ 20.0 (7a) |Dstpw / OTDw| ≦ 0.7 (8a) 0.1 ≦ |fis / ft| ≦ 1.8 (9a) 8.0 ≦ |νd_gave - νd_r| ≦ 55.0 (10a) Also, it is even more preferable to set the numerical ranges of Equations (2) to (10) as follows.

[0057] 25 ≦ νd_r ≦ 38 (2b) 1.55 ≦ nd_r ≦ 1.65 (3b) 0.007 ≦ dr / Dis ≦ 0.400 (4b) 0.3 ≦ |(1 - βist)βrt| ≦ 3.0 (5b) |(R2 + R1) / (R2 - R1)| ≦ 1.5 (6b) 2.0 ≦ Dmax / Dmin ≦ 15.0 (7b) |Dstpw / OTDw| ≦ 0.65 (8b) 0.15 ≦ |fis / ft| ≦ 1.50 (9b) 10.0 ≦ |νd_gave - νd_r| ≦ 52.0 (10b) In each embodiment, the resin layer Grep of the anti-vibration group IS preferably has an optical surface (air contact surface) that contacts air on either the object side or the image side. If both the object side and the image side of the resin layer Grep are joined to glass, it is not preferable because the chromatic aberration correction of the resin layer Grep cannot be sufficiently performed. Furthermore, the air contact surface of the resin layer Grep is preferably an aspherical surface. By making it an aspherical surface, it becomes possible to better correct the decentered coma aberration during the shift of the anti-vibration group IS.

[0058] In each embodiment, from the viewpoint of miniaturization and weight reduction, the anti-vibration group IS is preferably a single cemented lens in which the resin layer Grep and at least one lens other than the resin layer are all cemented.

[0059] In the embodiment of the zoom lens, the zoom lens includes, in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, and a rear group (L3~) on the image side of the second lens group, and the anti-vibration group IS is preferably included in the second lens group L2 or the rear group. According to such a configuration, it is possible to reduce the overall length of the zoom lens while reducing the diameter of the anti-vibration group IS. Note that the rear group may include at least one lens group.

[0060] Furthermore, in each embodiment, the resin layer Grep is preferably formed of an ultraviolet curable resin. By adopting the ultraviolet curable resin, it becomes possible to make the resin layer Grep thinner, which is preferable from the viewpoint of reducing the size and weight.

[0061] According to each embodiment, it is possible to realize high optical performance such as reducing the size and weight of the vibration-proof group IS while suppressing the occurrence of chromatic aberration during the shift of the vibration-proof group IS.

[0062] Hereinafter, numerical examples 1 to 5 corresponding to Examples 1 to 5 are shown. In each numerical example, the surface number i indicates the order of the optical surfaces when counted from the object side. r (mm) represents the radius of curvature of the i-th optical surface, and d (mm) represents the lens thickness or distance (air interval) on the optical axis between the i-th surface and the (i + 1)-th surface. nd is the refractive index with respect to the d-line of the optical material between the i-th surface and the (i + 1)-th surface. νdi is the Abbe number based on the d-line of the optical material between the i-th surface and the (i + 1)-th surface. The Abbe number νd is defined as follows when the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines are Nd, NF, and NC, respectively: νd=(Nd - 1) / (NF - NC) and is represented by.

[0063] Note that in each numerical example, d, focal length, F-number, and half field angle (°) are values in a state where the infinite object is focused. "BF" (back focus) is the distance on the optical axis from the final surface, which is the most image-side lens surface in the entire lens system, to the paraxial image plane, expressed in air-equivalent length. "Total lens length" is the length obtained by adding the back focus to the distance on the optical axis from the frontmost surface, which is the most object-side lens surface in the entire lens system, to the final surface.

[0064] The "*" attached to the surface number means that the surface is an aspherical surface. The shape of the aspherical surface is represented by the following formula when X is the displacement amount from the vertex of the surface in the optical axis direction, H is the height from the optical axis in the direction orthogonal to the optical axis, the direction of light propagation is positive, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10 are aspherical coefficients. "e-x" means ×10 -xmeans.

[0065]

Number

[0066] Table 1 summarizes the relationships between the conditions of formulas (1) to (10) and each example (numerical example). Lenses 1a to 1e in Examples 1 to 5 all satisfy the conditions of formulas (1) to (10) (furthermore, formulas (1a) to (10a) and formulas (1b) to (10b)). (Numerical Example 1) Unit: mm Surface data Surface number r d nd νd Effective diameter 1 287.836 2.20 1.84666 23.8 75.07 2 117.040 8.77 1.49700 81.5 72.42 3 -463.649 0.15 71.69 4 76.445 7.27 1.72916 54.7 67.41 5 288.757 (Variable) 66.52 6 130.630 1.40 1.88300 40.8 36.21 7 24.178 6.11 29.46 8 -231.647 1.00 1.53775 74.7 28.71 9 43.461 0.10 26.53 10 37.552 3.58 1.85478 24.8 26.29 11 74.422 4.10 24.78 12 -29.397 1.10 1.49700 81.5 24.36 13 560.309 2.50 1.85478 24.8 25.80 14 -82.474 (Variable) 26.38 15 (Aperture) ∞ (Variable) 27.44 16 44.442 4.32 1.89286 20.4 29.70 17 -8802.889 0.12 29.58 18 40.767 1.50 2.00100 29.1 29.23 19 23.094 11.28 1.49700 81.5 27.72 20 -29.992 0.29 27.34 21 -29.172 1.40 2.00069 25.5 27.15 22 474.342 2.01 28.12 23 84.351 5.21 1.49700 81.5 29.71 24 -52.194 0.82 30.06 25* -104.554 0.50 1.59022 30.1 30.09 26 -77.348 1.30 1.48749 70.2 30.09 27 111.339 (variable) 30.41 28 46.242 9.43 1.49700 81.5 36.90 29 -58.476 0.15 37.04 30* 63.823 0.16 1.59022 30.1 35.76 31 82.814 1.35 1.95906 17.5 35.69 32 46.540 5.00 2.00100 29.1 34.91 33 609.389 (variable) 34.38 34 186.529 3.09 1.95906 17.5 32.70 35 -171.732 0.15 32.13 36 -324.395 1.10 1.77047 29.7 31.62 37 33.303 (variable) 29.36 38* -29.257 0.45 1.59022 30.1 28.94 39 -25.615 1.60 1.72916 54.7 28.97 40 -94.099 (variable) 31.26 41 47.581 6.51 1.48749 70.2 40.90 42 ∞ (variable) 41.08 Image plane ∞ Aspherical data The 25th surface K = 0.00000e+000 A4 = 1.28501e-006 A6 = -9.97125e-010 A8 = 7.44439e-012 A10 = -2.13750e-014 A12 = 1.80140e-017 The 30th surface K = 0.00000e+000 A4 = -6.17655e-006 A6 = -9.03755e-010 A8 = -1.77689e-011 A10 = 4.08615e-014 A12 = -4.01447e-017 The 38th surface K = 0.00000e+000 A4 = -6.43322e-006 A6 = 1.45019e-008 A8 = -1.53727e-010 A10 = 6.74684e-013 A12 = -1.13415e-015 Various data Zoom ratio 4.71 Wide angle Middle Telephoto Focal length 24.72 61.33 116.36 F-number 2.91 2.91 2.91 Half field angle (°) 37.12 19.43 10.53 Image height 21.64 21.64 21.64 Overall lens length 178.45 191.24 204.02 BF 14.59 14.59 14.59 d5 0.90 29.26 50.55 d14 24.92 9.35 0.84 d15 17.38 5.86 1.50 d27 8.70 5.14 2.79 d33 1.50 5.17 4.79 d37 13.65 15.48 26.81 d40 0.80 10.38 6.14 d42 14.59 14.59 14.59 Entrance pupil position 36.26 88.83 157.67 Exit pupil position -107.74 -89.47 -70.91 Front principal point position 55.98 114.02 115.66 Rear principal point position -10.14 -46.74 -101.77 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 122.94 18.39 5.51 -5.87 2 6 -24.45 19.89 3.09 -12.16 3 16 70.96 28.74 -10.25 -26.71 4 28 32.41 16.09 4.32 -5.68 5 34 -69.15 4.34 3.43 1.03 6 38 -56.65 2.05 -0.44 -1.67 7 41 97.60 6.51 0.00 -4.37 Single lens data Lens Starting surface Focal length 1 1 -234.35 2 2 188.98 3 4 140.56 4 6 -33.81 5 8 -67.97 6 10 84.87 7 12 -56.17 8 13 84.26 9 16 49.54 10 18 -55.58 11 19 28.24 12 21 -27.42 13 23 65.71 14 25 500.22 15 26 -93.41 16 28 53.56 17 30 470.09 18 31 -112.84 19 32 50.11 20 34 93.62 21 36 -39.15 22 38 333.28 23 39 -48.75 24 41 97.60 (Numerical Example 2) Unit: mm Surface data Surface number r d nd νd Effective diameter 1 2087.789 2.20 2.00100 29.1 74.30 2 118.129 8.40 1.49700 81.5 70.56 3 -432.633 0.15 69.80 4 155.344 5.06 1.49700 81.5 65.50 5 -1452.229 0.00 64.65 6 78.029 5.78 1.81600 46.6 58.71 7 357.852 (Variable) 58.00 8 336.817 1.40 1.88300 40.8 44.02 9 29.285 7.33 35.80 10 -181.413 1.00 1.59522 67.7 35.46 11 67.132 0.11 33.57 12 43.305 3.00 1.85478 24.8 33.02 13 69.829 5.87 32.04 14 -37.040 1.10 1.49700 81.5 31.71 15 176.336 0.35 31.10 16 336.419 3.27 1.85478 24.8 31.10 17 -75.335 (Variable) 30.99 18 (Aperture) ∞ (Variable) 30.47 19 51.100 4.23 1.77830 23.9 33.04 20 646.565 12.18 32.94 21 31.714 1.50 2.00069 25.5 31.80 22 22.464 12.02 1.49700 81.5 30.03 23 -39.484 1.40 1.92286 18.9 29.28 24 -574.242 1.87 29.40 25* -183.377 0.20 1.56650 37.6 29.41 26 -156.034 4.62 1.92286 18.9 29.42 27 -32.348 1.30 1.84666 23.8 29.57 28 162.389 (Variable) 30.61 29* 113.215 0.05 1.59022 30.1 36.97 30 131.870 5.06 1.49700 81.5 37.13 31 -120.504 0.14 38.00 32 65.847 8.24 1.77250 49.6 40.03 33 -71.507 (Variable) 39.92 34 538.020 4.63 1.92286 18.9 35.17 35 -59.131 1.10 1.73800 32.3 34.60 36 42.302 (Variable) 31.63 37* -36.742 0.45 1.59022 30.1 30.74 38 -30.526 1.60 1.72916 54.7 30.75 39 -148.485 (Variable) 32.56 40 107.754 5.26 1.49700 81.5 39.78 41 -117.305 (Variable) 40.19 Image plane ∞ Aspherical data The 25th surface K = 0.00000e+000 A 4= 3.17809e-007 A 6= 6.04584e-010 A 8=-1.25210e-012 A10=-1.01467e-014 A12= 2.97341e-017 The 29th surface K = 0.00000e+000 A 4=-5.60367e-006 A 6= 1.76853e-009 A 8=-7.01013e-012 A10= 1.89743e-014 A12=-1.92142e-017 The 37th surface K = 0.00000e+000 A 4=-5.62020e-006 A 6=-1.34754e-009 A 8=-2.04562e-011 A10= 3.24662e-014 A12=-6.83028e-017 Various data Zoom ratio 4.71 Wide angle Middle Telephoto Focal length 24.73 39.98 116.36 F-number 2.91 2.91 2.91 Half field angle (°) 37.39 28.42 10.53 Image height 21.64 21.64 21.64 Overall lens length 213.46 213.46 213.46 BF 13.81 13.81 13.81 d 7 0.90 10.57 41.17 d17 40.70 31.03 0.43 d18 19.51 10.63 3.00 d28 10.18 6.80 2.30 d33 3.34 1.50 4.26 d36 13.36 17.76 27.79 d39 0.80 10.50 9.84 d41 13.81 13.81 13.81 Entrance pupil position 42.40 58.24 130.41 Exit pupil position -148.93 -125.59 -94.68 Front principal point position 63.37 86.76 121.98 Rear principal point position -10.91 -26.16 -102.54 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 106.16 21.59 11.21 -1.93 2 8 -28.55 23.42 2.16 -17.17 3 19 81.72 39.31 -24.35 -40.92 4 29 33.65 13.49 4.76 -3.70 5 34 -80.05 5.73 3.64 0.58 6 37 -64.06 2.05 -0.30 -1.51 7 40 113.89 5.26 1.70 -1.85 Single lens data Lens Starting surface Focal length 1 1 -125.16 2 2 187.66 3 4 282.66 4 6 121.16 5 8 -36.40 6 10 -82.20 7 12 126.77 8 14 -61.49 9 16 72.27 10 19 71.07 11 21 -83.76 12 22 30.79 13 23 -46.00 14 25 1842.37 15 26 43.44 16 27 -31.76 17 29 1354.57 18 30 127.54 19 32 45.57 20 34 57.94 21 35 -33.26 22 37 297.68 23 38 -53.00 24 40 113.89 (Numerical Example 3) Unit: mm Surface data Surface number r d nd νd Effective diameter 1 304.000 2.20 1.84666 23.8 71.53 2 92.955 9.24 1.49700 81.5 65.89 3 -371.952 0.15 64.74 4 76.828 5.61 1.83481 42.7 56.54 5 364.502 (Variable) 55.27 6 421.524 1.40 1.88300 40.8 46.29 7 30.091 7.99 37.33 8 -159.885 1.00 1.49700 81.5 36.91 9 51.475 0.08 34.34 10 43.008 3.06 2.05090 26.9 34.07 11 67.114 6.21 33.04 12 -38.079 1.10 1.49700 81.5 32.68 13 327.741 4.59 1.85478 24.8 32.00 14 -81.468 (Variable) 31.67 15 (Aperture) ∞ (Variable) 32.41 16 54.786 3.49 1.92286 18.9 34.29 17 177.454 8.45 34.14 18 30.263 1.50 2.00069 25.5 33.97 19 22.637 10.55 1.49700 81.5 32.06 20 -147.905 0.13 31.31 21 -282.889 1.40 1.80810 22.8 31.07 22 58.671 1.50 30.32 23* 56.597 0.05 1.59022 30.1 30.43 24 52.518 5.69 1.49700 81.5 30.39 25 -75.427 2.44 30.41 26 -47.713 1.30 1.80810 22.8 30.40 27 159.626 (Variable) 31.74 28* 84.668 0.07 1.59022 30.1 38.87 29 106.190 5.61 1.49700 81.5 39.01 30 -99.010 0.15 39.77 31 84.097 7.77 1.90043 37.4 41.84 32 -75.592 (Variable) 41.78 33 293.202 3.43 1.98612 16.5 36.51 34 -121.711 0.15 35.94 35 -172.611 1.10 1.90043 37.4 35.22 36 43.474 (variable) 32.84 37* -30.478 0.45 1.59022 30.1 32.11 38 -27.469 1.60 1.72916 54.7 32.14 39 -70.075 (variable) 34.71 40 65.669 5.25 1.72916 54.7 43.05 41 ∞ (variable) 43.06 Image plane ∞ Aspherical data The 23rd surface K = 0.00000e+000 A 4=-1.56777e-006 A 6=-2.16556e-009 A 8= 6.57664e-012 A10=-1.33254e-014 A12= 1.71769e-017 The 28th surface K = 0.00000e+000 A 4=-5.98706e-006 A 6= 4.16976e-009 A 8=-1.36129e-011 A10= 2.95803e-014 A12=-2.54789e-017 The 37th surface K = 0.00000e+000 A 4=-2.64638e-006 A 6= 2.34537e-009 A 8=-3.38245e-011 A10= 9.90165e-014 A12=-1.71434e-016 Various data Zoom ratio 4.71 Wide angle Middle Telephoto Focal length 24.72 39.97 116.37 F-number 2.91 2.91 2.91 Half field angle (°) 37.12 28.42 10.53 Image height 21.64 21.64 21.64 Overall lens length 208.46 208.46 208.46 BF 13.50 13.50 13.50 d 5 0.90 9.49 38.99 d14 38.94 30.35 0.85 d15 22.77 12.22 1.50 d27 8.95 6.28 2.34 d32 3.41 1.62 4.50 d36 14.49 18.45 28.45 d39 0.80 11.86 13.62 d41 13.50 13.50 13.50 Entrance pupil position 41.45 55.51 122.04 Exit pupil position -253.62 -186.07 -135.48 Front principal point position 63.88 87.48 147.51 Rear principal point position -11.22 -26.47 -102.87 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 110.47 17.20 7.03 -3.52 2 6 -30.54 25.43 1.82 -18.95 3 16 90.23 36.48 -35.10 -44.29 4 28 31.24 13.60 4.81 -3.51 5 33 -70.22 4.68 3.27 0.78 6 37 -72.71 2.05 -0.81 -2.04 7 40 90.06 5.25 0.00 -3.04 Single lens data Lens Starting surface Focal length 1 1 -158.91 2 2 150.63 3 4 115.58 4 6 -36.76 5 8 -78.22 6 10 106.98 7 12 -68.57 8 13 76.73 9 16 84.72 10 18 -99.56 11 19 40.33 12 21 -60.02 13 23 -1240.33 14 24 63.23 15 26 -45.33 16 28 706.86 17 29 104.04 18 31 45.25 19 33 87.58 20 35 -38.47 21 37 446.65 22 38 -62.96 23 40 90.06 (Numerical Example 4) Unit: mm Surface data Surface number r d nd νd Effective diameter 1 70.752 6.52 1.90043 37.4 56.88 2 440.500 0.15 56.29 3 57.565 9.57 1.49700 81.5 52.51 4 -332.389 2.00 1.88300 40.8 50.73 5 84.915 0.15 47.13 6 50.200 6.94 1.49700 81.5 45.81 7 334.045 0.15 44.29 8 135.929 2.00 1.67270 32.1 43.09 9 32.936 2.62 38.36 10 49.461 4.03 1.72916 54.7 38.26 11 142.439 (Variable) 37.51 12 (Diaphragm) ∞ 2.30 36.57 13 -555.457 1.68 1.92286 18.9 35.07 14 -154.056 1.30 1.59522 67.7 34.74 15 38.151 (Variable) 32.08 16* 414.834 0.50 1.59022 30.1 29.58 17 -615.628 1.00 1.82522 41.7 29.57 18 78.957 (Variable) 29.25 19 41.210 11.92 1.59522 67.7 32.94 20 -28.912 1.30 1.66565 35.6 33.86 21 298.910 0.19 36.43 22 197.707 1.80 1.80810 22.8 36.77 23 32.848 11.15 1.88300 40.8 38.82 24 -92.968 1.75 39.36 25 -59.032 1.80 1.57197 38.1 39.36 26 35.777 11.74 1.99202 27.0 42.46 27 -100.164 8.69 42.17 28* -50.963 2.00 1.76802 49.2 37.57 29 -3568.112 (Variable) 38.81 Image plane ∞ Aspherical data The 16th surface K = 0.00000e+000 A4 = 1.59786e-007 A6 = 1.73424e-009 A8 = -1.56292e-012 The 28th surface K = 0.00000e+000 A 4=-1.01224e-005 A 6= 2.28729e-008 A 8=-1.22091e-010 A10= 2.83964e-013 A12=-2.41602e-016 Focal length 82.47 F-number 1.45 Half field angle (°) 14.70 Image height 21.64 Overall lens length 126.52 BF 13.50 d11 2.50 d15 16.06 d18 1.20 d29 13.50 Entrance pupil position 40.78 Exit pupil position -67.48 Front principal point position 39.26 Rear principal point position -68.97 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 79.48 34.14 -7.82 -27.66 2 12 -66.01 5.28 3.91 -0.07 3 16 -106.39 1.50 0.97 0.11 4 19 39.11 52.34 1.11 -28.22 Single lens data Lens Starting surface Focal length 1 1 92.84 2 3 99.54 3 4 -76.43 4 6 117.91 5 8 -65.13 6 10 102.05 7 13 230.54 8 14 -51.24 9 16 419.97 10 17 -84.75 11 19 30.48 12 20 -39.54 13 22 -48.99 14 23 28.68 15 25 -38.68 16 26 27.77 17 28 -67.34 (Numerical Example 5) Unit: mm Surface data Surface number r d nd νd Effective diameter 1 88.418 1.50 1.88300 40.8 58.70 2 63.666 8.74 1.49700 81.5 57.43 3 -833.690 (Variable) 57.10 4* -106.403 1.00 1.59022 30.1 32.47 5 -64.250 1.10 1.72916 54.7 32.47 6 29.236 4.74 1.76200 40.1 32.73 7 79.904 1.26 32.74 8 94.393 4.99 1.76182 26.5 33.09 9 -71.324 0.15 33.14 10 90.907 5.93 1.49700 81.5 32.03 11 -45.508 1.25 2.05090 26.9 31.47 12 896.670 1.06 31.34 13 (Diaphragm) ∞ (Variable) 31.31 14 126.596 1.30 2.05090 26.9 34.71 15 52.713 7.76 1.58313 59.4 34.97 16 -72.568 0.15 35.80 17 67.589 3.92 1.72916 54.7 36.93 18 -1930.147 (Variable) 36.79 19 509.219 1.15 1.53775 74.7 29.60 20 28.124 (Variable) 28.85 21 -57.869 6.04 1.59270 35.3 31.10 22 -22.224 1.60 1.49700 81.5 31.77 23 -4514.292 (Variable) 34.70 Image plane ∞ Aspherical data Fourth surface K = 0.00000e+000 A4 = 6.85519e-007 A6 = 4.19594e-009 A8 = -4.15125e-011 A10 = 2.06560e-013 A12 = -3.86264e-016 Various data Zoom ratio 3.76 Wide angle Medium Telephoto Focal length 103.16 216.79 387.89 F-number 4.64 6.50 7.30 Half field angle (°) 11.84 5.70 3.19 Image height 21.64 21.64 21.64 Overall lens length 176.10 235.23 288.59 BF 15.98 50.92 63.01 d3 2.11 61.24 114.60 d13 61.57 37.67 27.84 d18 29.18 15.57 1.86 d20 13.60 16.18 27.63 d23 15.98 50.92 63.01 Entrance pupil position 24.02 127.92 345.02 Exit pupil position -64.37 -51.72 -52.41 Front principal point position -5.27 -113.18 -570.71 Rear principal point position -87.18 -165.87 -324.88 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 219.80 10.24 -0.19 -6.85 2 4 -225.92 21.49 4.50 -8.67 3 14 53.78 13.13 5.57 -2.43 4 19 -55.40 1.15 0.79 0.04 5 21 -176.88 7.64 -2.98 -7.96 Single lens data Lens Starting surface Focal length 1 1 -265.09 2 2 119.40 3 4 272.37 4 5 -27.42 5 6 58.15 6 8 54.03 7 10 61.91 8 11 -41.18 9 14 -86.73 10 15 53.58 11 17 89.63 12 19 -55.40 13 21 57.26 14 22 -44.94

[0067]

Table 1

[0068] FIG. 21 shows a digital still camera 10 as an imaging device using the lenses (1a to 1e) of each embodiment as an imaging optical system. In FIG. 21, 113 is the camera body, and 111 is the imaging optical system. 112 is an imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor that is built into the camera body 113 and receives the optical image formed by the imaging optical system 111 to perform imaging (photoelectric conversion). The camera body 113 may be a single-lens reflex camera having a quick-turn mirror or a mirrorless camera without a quick-turn mirror.

[0069] According to each embodiment, it is possible to provide an imaging device in which the lens barrel that houses the imaging optical system is small and lightweight, and high optical performance can be obtained even when the anti-vibration group is shifted.

[0070] Each of the embodiments described above is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Explanation of Reference Numerals

[0071] 1a to 1e Lenses L1 to L7 Lens Groups SP Aperture Stop IS Anti-Vibration Group Grep Resin Layer IP Image Plane

Claims

1. An optical system comprising, 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, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with negative refractive power, wherein the distance between adjacent lens groups changes during zooming, and having a movable group that is movable in a direction eccentric with respect to the optical axis, the movable group includes a resin layer and a lens joined to each other, the movable group is included in the second lens group, when the focal length of the resin layer is fr and the focal length of the movable group is fis, -0.95 ≤ fis / fr < 0 and satisfying the condition.

2. when the Abbe number of the resin layer based on the d-line is νd_r, 15 ≤ νd_r ≤ 40 and satisfying the condition, the optical system according to Claim 1.

3. when the refractive index of the resin layer with respect to the d-line is nd_r, 1.50 ≤ nd_r ≤ 1.75 and satisfying the condition, the optical system according to Claim 1 or 2.

4. when the thickness of the resin layer on the optical axis is dr and the total thickness of the movable group on the optical axis is Dis, 0.001 ≤ dr / Dis ≤ 0.850 and satisfying the condition, the optical system according to any one of Claims 1 to 3.

5. in the state where the focal length of the optical system is maximum, when the lateral magnification of the movable group is βist and the combined lateral magnification of all lenses arranged on the image side of the movable group is βrt, 0.1 ≤ |(1 - βist)βrt| ≤ 5.0 and satisfying the condition, the optical system according to any one of Claims 1 to 4.

6. When the radius of curvature of the lens surface closest to the object side in the movable group is R1 and the radius of curvature of the lens surface closest to the image side in the movable group is R2, |(R2 + R1) / (R2 - R1)| ≤ 2.0 The optical system according to any one of claims 1 to 5, characterized in that the condition is satisfied.

7. When the maximum thickness in the optical axis direction of the resin layer is Dmax and the minimum thickness is Dmin, 1.1 ≤ Dmax / Dmin ≤ 30.0 The optical system according to any one of claims 1 to 6, characterized in that the condition is satisfied.

8. The optical system has a diaphragm disposed on the object side of the movable group, In a state where the focal length of the optical system is minimum, when the distance on the optical axis from the diaphragm to the movable group is Dstpw and the distance on the optical axis from the lens surface closest to the object side in the optical system to the image plane is OTDw, |Dstpw / OTDw| ≤ 0.8 The optical system according to any one of claims 1 to 7, characterized in that the condition is satisfied.

9. When the maximum focal length of the optical system is ft, 0.05 ≤ | fis / ft | ≤ 2.00 The optical system according to any one of claims 1 to 8, characterized in that the condition is satisfied.

10. When the Abbe number of the resin layer based on the d-line is νd_r and the average Abbe number of the lenses other than the resin layer included in the movable group is νd_gave, 5.0 ≤ |νd_gave - νd_r| ≤ 60.0 The optical system according to any one of claims 1 to 9, characterized in that the condition is satisfied.

11. The resin layer has an optical surface in contact with air. The optical system according to any one of claims 1 to 10, characterized in that.

12. The optical system according to claim 11, wherein the optical surface is an aspherical surface.

13. The optical system according to any one of claims 1 to 12, wherein the movable group is composed of the resin layer joined to each other and at least one lens.

14. The optical system according to any one of claims 1 to 13, wherein the resin layer is made of an ultraviolet curable resin.

15. Comprising a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, a sixth lens group with negative refractive power, and a seventh lens group with positive refractive power, arranged in order from the object side to the image side, the distance between adjacent lens groups changing during zooming, having a movable group movable in a direction eccentric with respect to the optical axis, the movable group including a resin layer and a lens joined to each other, the movable group being included in the third lens group, When the focal length of the resin layer is fr, the focal length of the movable group is fis, and the Abbe number based on the d-line of the resin layer is νd_r, -0.95 ≤ fis / fr < 0 15 ≤ νd_r ≤ 40 An optical system characterized by satisfying the following conditions.

16. Comprising a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, and a fourth lens group with positive refractive power, arranged in order from the object side to the image side, the distance between adjacent lens groups changing during zooming, having a movable group movable in a direction eccentric with respect to the optical axis, the movable group including a resin layer and a lens joined to each other, the movable group being included in the third lens group, When the focal length of the resin layer is fr, the focal length of the movable group is fis, the Abbe number of the resin layer based on the d line is νd_r, and the average Abbe number of the lenses other than the resin layer included in the movable group is νd_gave, -0.95 ≤ fis / fr < 0 5.0 ≤ |νd_gave - νd_r| ≤ 60.0 An optical system characterized by satisfying the following conditions.

17. The optical system according to any one of claims 1 to 16, wherein the movable group moves during image blur correction.

18. The optical system according to any one of claims 1 to 17, An imaging device comprising an imaging element that images an object through the optical system.

Images