Zoom Lenses and Optics

Abstract

To provide a zoom lens with a high zoom ratio. [Solution] The optical system essentially consists of five lens groups: a first lens group G1 with positive refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power, arranged in order from the object side along the optical axis. When changing magnification from the wide-angle end state to the telephoto end state, the spacing between adjacent lens groups changes, and when changing magnification from the wide-angle end state to the telephoto end state, the first lens group moves toward the object side. The first lens group has a cemented lens of a negative lens L11 and a positive lens L12 arranged in order from the object side along the optical axis. The third lens group has at least two positive single lenses L31 and L35, with a positive single lens L51 located closest to the object side.

Description

[Technical field]

[0001] The present invention relates to a zoom lens and an optical apparatus using the same. [Background technology]

[0002] Conventionally, as a wide-angle zoom lens with a zoom ratio of about 4 times, a zoom lens has been proposed that is composed of, in order from the object side along the optical axis, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a fourth lens group with negative refractive power, and that changes magnification by moving each lens group (see, for example, Patent Document 1). The zoom lens proposed in Patent Document 1 achieves a magnification ratio of about 4 times and an aperture ratio of about F-number 2.8 to 6 by moving the first to fourth lens groups during magnification, but there is a demand for a larger aperture and higher magnification. In particular, there is a demand for a zoom lens with a high magnification ratio suitable for video cameras, electronic still cameras, etc. using solid-state imaging devices, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-247758 A Summary of the Invention

[0004] A zoom lens according to a first aspect includes five lens groups, arranged in order from the object side along the optical axis, including a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power, wherein, when zooming from the wide-angle end state to the telephoto end state, a distance between adjacent lens groups changes, and when zooming from the wide-angle end state to the telephoto end state, the first lens group moves toward the object side, and the first lens group includes a cemented lens of a negative lens and a positive lens arranged in order from the object side along the optical axis, the third lens group includes at least two positive single lenses, and includes a cemented lens of a negative lens and a positive lens arranged in order from the object side, with the positive single lens disposed closest to the object side, the fourth lens group has a negative single lens, The fifth lens group Positive single lens and satisfies the following conditional expression:

[0005] 2.90<|MV5 / MV2|<11.50 0.10<(β2t×β4w) / (β2w×β4t)<2.40 where MV5 is the amount by which the fifth lens group moves with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount by which the fifth lens group moves corresponds to the distance between the position of the fifth lens group in the wide-angle end state and the position of the fifth lens group in the telephoto end state). MV2: the amount by which the second lens group moves with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount by which the second lens group moves corresponds to the distance between the position of the second lens group in the wide-angle end state and the position of the second lens group in the telephoto end state). β2t: Magnification of the second lens group in the telephoto end state β2w: Magnification of the second lens group in the wide-angle end state β4t: Magnification of the fourth lens group in the telephoto end state β4w: Magnification of the fourth lens group in the wide-angle end state

[0006] A zoom lens according to a second aspect includes five lens groups arranged in order from the object side along the optical axis, namely, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power, wherein, when changing magnification from the wide-angle end state to the telephoto end state, a distance between adjacent lens groups changes, when changing magnification from the wide-angle end state to the telephoto end state, the first lens group moves toward the object side, and when changing magnification from the wide-angle end state to the telephoto end state, the position of the second lens group in the telephoto end state is closer to the image surface side than the position of the second lens group in the wide-angle end state, a position of the fifth lens group in the telephoto end state is closer to the image plane side than a position of the fifth lens group in the wide-angle end state; The first lens group has a cemented lens of a negative lens and a positive lens arranged in order from the object side along the optical axis, the third lens group has at least two positive single lenses and a positive single lens is arranged closest to the object side, and the fifth lens group has a positive single lens, and satisfies the following conditional expression:

[0007] 3.78≦|MV5 / MV2|≦7.94 where MV5 is the amount by which the fifth lens group moves with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount by which the fifth lens group moves corresponds to the distance between the position of the fifth lens group in the wide-angle end state and the position of the fifth lens group in the telephoto end state). MV2: the amount by which the second lens group moves with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount by which the second lens group moves corresponds to the distance between the position of the second lens group in the wide-angle end state and the position of the second lens group in the telephoto end state).

[0008] An optical device according to a third aspect is configured by mounting the zoom lens described above. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a lens configuration of a zoom lens according to a first example of the present embodiment. [Diagram 2] 2(a), 2(b) and 2(c) are diagrams showing various aberrations of the zoom lens according to Example 1 in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively. [Diagram 3] FIG. 11 is a cross-sectional view showing the lens configuration of a zoom lens according to a second example of the present embodiment. [Figure 4] 4(a), 4(b) and 4(c) are diagrams showing various aberrations of the zoom lens according to the second example in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively. [Diagram 5] FIG. 11 is a cross-sectional view showing the lens configuration of a zoom lens according to a third example of the present embodiment. [Figure 6] 6(a), 6(b) and 6(c) are diagrams showing various aberrations of the zoom lens according to the third example in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively. [Figure 7] FIG. 11 is a cross-sectional view showing the lens configuration of a zoom lens according to Example 4 of the present embodiment. [Figure 8] 8(a), 8(b) and 8(c) are diagrams showing various aberrations of the zoom lens according to Example 4 in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively. [Figure 9] FIG. 1 is a schematic diagram showing the configuration of a camera equipped with a zoom lens according to an embodiment of the present invention. [Figure 10] 4 is a flowchart outlining a method for manufacturing the zoom lens according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the zoom lens and the optical device according to the first and second embodiments of the present application will be described with reference to the drawings. As shown in FIG. 1, the zoom lens ZL(1) as an example of the zoom lens ZL according to the first embodiment of the present application is configured to include, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. In the zoom lens ZL according to the first embodiment of the present application, when changing magnification from the wide-angle end state to the telephoto end state, each of the adjacent lens groups (i.e., the first to fifth lens groups G1 to G5) moves in the optical axis direction as shown by the arrows in FIG. 1. With such a configuration, the zoom lens ZL according to the first embodiment of the present application satisfies the following conditional expression (1).

[0011] 2.90<|MV5 / MV2|<11.50 ···(1) MV5: the amount of movement of the fifth lens group with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state MV2: the amount of movement of the second lens group with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state

[0012] The zoom lens ZL according to the first embodiment of the present application is the zoom lens ZL(2) shown in FIG. 5 or the zoom lens ZL(4) shown in FIG.

[0013] By configuring the zoom lens ZL of the first embodiment of the present application as described above, it is possible to achieve a wider angle and higher magnification while maintaining the overall lens size and the coma and astigmatism aberrations. According to the first embodiment of the present application, it is possible to obtain a zoom lens suitable for video cameras, electronic still cameras, etc., that use solid-state imaging devices, etc.

[0014] The above conditional expression (1) defines the appropriate range of the ratio of the movement amount of the second lens group to the fifth lens group when changing magnification from the wide-angle end to the telephoto end. If this conditional expression is exceeded or exceeded, coma aberration and astigmatism will worsen, which is not preferable.

[0015] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (1) to 3.10. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (1) to 3.30. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (1) to 3.50. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (1) to 11.00. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (1) to 10.50. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (1) to 10.00.

[0016] It is preferable that the zoom lens ZL according to the first embodiment of the present application satisfies the following conditional expression (3). 6.00<|MV4 / MV2|<15.00 ···(3) where MV4 is the amount of movement of the fourth lens group with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state.

[0017] Condition (3) defines the appropriate range of the ratio of the movement amount of the second lens group to the fourth lens group when changing magnification from the wide-angle end to the telephoto end. It is not preferable to exceed or fall short of this condition, since coma and astigmatism will worsen.

[0018] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 7.00. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 8.00. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 9.00. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 14.50. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 14.00. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 13.40.

[0019] In the zoom lens ZL according to the first embodiment of the present invention, it is preferable that the fifth lens group G5 moves toward the image (I) along the optical axis when changing the magnification from the wide-angle end state to the telephoto end state, thereby achieving a high magnification and reducing various aberrations such as astigmatism.

[0020] It is preferable that the zoom lens ZL according to the first embodiment of the present application satisfies the following conditional expression (2). 1.20<β2t / β2w<2.50 (2) where β2t is the magnification of the second lens group in the telephoto end state. β2w: Magnification of the second lens group in the wide-angle end state

[0021] Condition (2) defines the appropriate range of the ratio of the magnifications of the second lens group at the wide-angle end and the telephoto end. If this condition is exceeded or not exceeded, coma and astigmatism will increase, which is undesirable.

[0022] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (2) to 1.25. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (2) to 1.30. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (2) to 1.35. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (2) to 2.10. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (2) to 2.30. Furthermore, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (2) to 1.90.

[0023] It is preferable that the zoom lens ZL according to the first embodiment of the present application satisfies the following conditional expression (4). 0.10<(β2t×β4w) / (β2w×β4t)<2.40 (4) where β4t is the magnification of the fourth lens group in the telephoto end state. β4w: Magnification of the fourth lens group in the wide-angle end state

[0024] Condition (4) defines the appropriate range of the magnification change ratio between the second lens group and the fourth lens group when zooming from the wide-angle end to the telephoto end. It is not preferable to exceed or fall short of this condition, since coma and astigmatism will worsen.

[0025] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (4) to 0.40. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (4) to 0.70. In addition, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (4) to 1.00. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (4) to 2.20. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (4) to 2.00. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (4) to 1.80.

[0026] It is preferable that the zoom lens ZL according to the first embodiment of the present application satisfies the following conditional expression (5). 1.50 <TLt / ft<5.00 ···(5) Where TLt: total length of zoom lens at telephoto end ft: focal length of entire zoom lens at telephoto end

[0027] Condition (5) defines the appropriate range of the ratio of the total length to the focal length at the telephoto end. It is not preferable to exceed or fall short of this condition, since both of these conditions result in increased spherical aberration, coma, and astigmatism.

[0028] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 1.70. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 1.90. In addition, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 2.10. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 4.60. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 4.20. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 3.70.

[0029] It is desirable for the zoom lens of the first embodiment of the present application to satisfy the following conditional expression (6). 28.0<ωw<65.0 (6) Where ωw: half angle of view of the entire zoom lens at the wide-angle end (unit: degree)

[0030] Condition (6) defines the optimum value of the half angle of view at the wide-angle end. By satisfying this condition, it is possible to obtain a wide half angle of view while effectively correcting various aberrations such as coma, field curvature, and distortion.

[0031] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (6) to 30.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (6) to 32.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (6) to 35.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (6) to 38.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the lower limit value of conditional formula (6) to 40.0. In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (6) to 60.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (6) to 55.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (6) to 50.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (6) to 46.0.

[0032] It is desirable for the zoom lens of the first embodiment of the present application to satisfy the following conditional expression (7). 5.0<ωt<25.0 (7) Where ωt is the half angle of view of the entire zoom lens at the telephoto end (unit: degree)

[0033] Condition (7) defines the optimum half angle of view at the telephoto end. By satisfying this condition, various aberrations such as coma, field curvature, and distortion can be effectively corrected.

[0034] In order to ensure the effects of the first embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 7.0. In order to further ensure the effects of the first embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 9.0. Furthermore, in order to further ensure the effects of the first embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 10.0. Furthermore, in order to further ensure the effects of the first embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 12.0.

[0035] In order to ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 23.0. In order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 21.0. In addition, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 19.0. In addition, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 17.0. In addition, in order to further ensure the effect of the first embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 16.0.

[0036] In the zoom lens ZL according to the first embodiment of the present application, it is preferable that at least a part of the fourth lens group is a focusing lens. This makes it possible to reduce the fluctuation of various aberrations such as spherical aberration and coma aberration during focusing. In addition, when focusing from infinity to a close-distance object, at least a part of the fourth lens group constituting the focusing lens moves toward the image side in the optical axis direction.

[0037] In the zoom lens ZL according to the first embodiment of the present application, it is preferable that at least a part of the third lens group constitutes an anti-vibration lens group having a displacement component perpendicular to the optical axis, thereby making it possible to reduce fluctuations in various aberrations such as coma aberration during image stabilization.

[0038] The optical device according to the first embodiment of the present application is configured to include the zoom lens ZL according to the first embodiment of the present application described above. As a specific example, a camera (optical device) including the zoom lens ZL will be described with reference to FIG. 9. This camera 1 is a digital camera including the zoom lens ZL according to the first embodiment of the present application as a photographing lens 2 as shown in FIG. 9. In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and reaches the image sensor 3. As a result, the light from the subject is captured by the image sensor 3 and recorded as a subject image in a memory (not shown). In this way, the photographer can capture a subject using the camera 1. This camera may be a mirrorless camera or a single-lens reflex type camera having a quick-return mirror.

[0039] With the above-described configuration, a camera 1 equipped with the zoom lens ZL according to the first embodiment of the present application as the photographing lens 2 is suitable for video cameras, electronic still cameras, etc. that use solid-state imaging devices, etc., and can achieve wide-angle, high-magnification performance while keeping the overall lens size small and maintaining astigmatism and chromatic aberration.

[0040] Next, a manufacturing method of the zoom lens ZL according to the first embodiment of the present application will be outlined with reference to FIG. 10. First, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power are arranged side by side in a lens barrel (step ST1). Next, the lens groups G1 to G5 are configured so that the intervals between adjacent lens groups G1 to G5 change when zooming from the wide-angle end state to the telephoto end state (step ST2). Furthermore, a predetermined conditional expression, i.e., the above conditional expression (1) is satisfied (step ST3).

[0041] According to the manufacturing method of the first embodiment of the present application, it is possible to manufacture a zoom lens that can satisfactorily correct various aberrations and has a wide angle, large aperture, and excellent optical performance.

[0042] Next, a second embodiment of the present application will be described. As shown in FIG. 1, a zoom lens ZL(1) as an example of the zoom lens ZL according to the second embodiment of the present application is configured to include, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. In the zoom lens ZL according to this embodiment, when changing magnification from the wide-angle end state to the telephoto end state, each of the adjacent lens groups (i.e., the first to fifth lens groups G1 to G5) moves in the optical axis direction as shown by the arrows in FIG. 1. With such a configuration, the zoom lens ZL according to the second embodiment of the present application satisfies the following conditional expression (3).

[0043] 6.00<|MV4 / MV2|<15.00 ···(3) where MV4 is the amount of movement of the fourth lens group with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state. MV2: the amount of movement of the second lens group with respect to the image plane when changing magnification from the wide-angle end state to the telephoto end state

[0044] Condition (3) defines the appropriate range of the ratio of the movement amount of the second lens group to the fourth lens group when changing magnification from the wide-angle end to the telephoto end. It is not preferable to exceed or fall short of this condition, since coma and astigmatism will worsen.

[0045] In order to ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 7.00. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 8.00. Furthermore, in order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (3) to 9.00. In order to ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 14.50. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 14.00. Furthermore, in order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (3) to 13.40.

[0046] In the zoom lens ZL according to the second embodiment of the present invention, it is preferable that the fifth lens group G5 moves toward the image (I) along the optical axis when changing the magnification from the wide-angle end state to the telephoto end state, thereby achieving a high magnification and reducing various aberrations such as astigmatism.

[0047] It is preferable that the zoom lens ZL according to the second embodiment of the present application satisfies the following conditional expression (2). 1.20<β2t / β2w<2.50 (2) where β2t is the magnification of the second lens group in the telephoto end state. β2w: Magnification of the second lens group in the wide-angle end state

[0048] Condition (2) defines the appropriate range of the ratio of the magnification of the second lens group at the wide-angle end to the telephoto end. It is not preferable to exceed or fall short of this condition, since both will result in increased coma and astigmatism.

[0049] In order to ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (2) to 1.25. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (2) to 1.30. In addition, in order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (2) to 1.35. In order to ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (2) to 2.10. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (2) to 2.30. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (2) to 1.90.

[0050] It is preferable that the zoom lens ZL according to the second embodiment of the present application satisfies the following conditional expression (4). 0.10<(β2t×β4w) / (β2w×β4t)<2.40 (4) where β4t is the magnification of the fourth lens group in the telephoto end state. β4w: Magnification of the fourth lens group in the wide-angle end state

[0051] Condition (4) defines the appropriate range of the magnification change ratio between the second lens group and the fourth lens group when zooming from the wide-angle end to the telephoto end. It is not preferable to exceed or fall short of this condition, since coma and astigmatism will worsen.

[0052] In order to ensure the effects of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (4) to 0.40. In order to further ensure the effects of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (4) to 0.70. Furthermore, in order to further ensure the effects of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (4) to 1.00. In order to ensure the effects of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (4) to 2.20. In order to further ensure the effects of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (4) to 2.00. Furthermore, in order to further ensure the effects of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (4) to 1.00. A value of 1.80 is preferred.

[0053] It is preferable that the zoom lens ZL according to the second embodiment of the present application satisfies the following conditional expression (5). 1.50 <TLt / ft<5.00 ···(5) Where TLt: total length of zoom lens at telephoto end ft: focal length of entire zoom lens at telephoto end

[0054] Condition (5) defines the appropriate range of the ratio of the total length to the focal length at the telephoto end. It is not preferable to exceed or fall short of this condition, since both of these conditions result in increased spherical aberration, coma, and astigmatism.

[0055] In order to ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 1.70. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 1.90. In addition, in order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit value of conditional formula (5) to 2.10. In order to ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 4.60. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 4.20. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (5) to 3.70.

[0056] It is desirable for the zoom lens of the second embodiment of the present application to satisfy the following conditional expression (6). 28.0<ωw<65.0 (6) Where ωw: half angle of view of the entire zoom lens at the wide-angle end (unit: degree)

[0057] Condition (6) defines the optimum value of the half angle of view at the wide-angle end. By satisfying this condition, it is possible to obtain a wide half angle of view while effectively correcting various aberrations such as coma, field curvature, and distortion.

[0058] In order to ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (6) to 30.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (6) to 32.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (6) to 35.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (6) to 38.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the lower limit of conditional formula (6) to 40.0. In order to ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (6) to 60.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (6) to 55.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (6) to 50.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit of conditional formula (6) to 46.0.

[0059] It is desirable for the zoom lens of the second embodiment of the present application to satisfy the following conditional expression (7). 5.0<ωt<25.0 (7) Where ωt is the half angle of view of the entire zoom lens at the telephoto end (unit: degree)

[0060] Condition (7) defines the optimum half angle of view at the telephoto end. By satisfying this condition, various aberrations such as coma, field curvature, and distortion can be effectively corrected.

[0061] In order to ensure the effect of the second embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 7.0. In order to further ensure the effect of the second embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 9.0. In addition, in order to further ensure the effect of the second embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 10.0. In order to further ensure the effect of the second embodiment of the present invention, it is preferable to set the lower limit of conditional formula (7) to 12.0.

[0062] In order to ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 23.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 21.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 19.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 17.0. In order to further ensure the effect of the second embodiment of the present application, it is preferable to set the upper limit value of conditional formula (7) to 16.0.

[0063] In the zoom lens ZL according to the second embodiment of the present invention, it is preferable that at least a part of the fourth lens group is a focusing lens. This makes it possible to reduce the fluctuation of various aberrations such as spherical aberration and coma aberration during focusing. In addition, when focusing from infinity to a close-distance object, at least a part of the fourth lens group constituting the focusing lens moves toward the image side in the optical axis direction.

[0064] In the zoom lens ZL according to the second embodiment of the present invention, it is preferable that at least a part of the third lens group constitutes an anti-vibration lens group having a displacement component perpendicular to the optical axis, thereby making it possible to reduce fluctuations in various aberrations such as coma during image stabilization.

[0065] The optical device according to the second embodiment of the present application is configured to include the zoom lens ZL according to the second embodiment of the present application described above. As a specific example, a camera (optical device) camera 1 equipped with the zoom lens ZL is a digital camera having the same configuration as the camera shown in Fig. 9 and equipped with the zoom lens ZL according to the second embodiment of the present application as a photographing lens 2. The configuration is the same as the camera equipped with the zoom lens ZL according to the first embodiment of the present application, so a detailed description thereof will be omitted.

[0066] With the above-described configuration, a camera 1 equipped with the zoom lens ZL according to the second embodiment of the present application as the photographing lens 2 is suitable for video cameras, electronic still cameras, etc. that use solid-state imaging devices, etc., and can achieve wide-angle, high-magnification performance while keeping the overall lens size small and maintaining astigmatism and chromatic aberration.

[0067] Next, a manufacturing method of the zoom lens ZL according to the second embodiment of the present application will be outlined with reference to FIG. 10. FIG. 10 was also used to explain the manufacturing method of the first embodiment of the present application, and the manufacturing method of the second embodiment of the present application will also be explained with reference to this figure. First, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power are arranged side by side in a lens barrel (step ST1). Next, the lens groups G1 to G5 are configured so that the intervals between adjacent lens groups G1 to G5 change when zooming from the wide-angle end state to the telephoto end state (step ST2). Furthermore, a predetermined conditional expression, i.e., the above conditional expression (3) is satisfied (step ST3).

[0068] According to the manufacturing method of the second embodiment of the present invention, it is possible to manufacture a wide-angle, large-aperture zoom lens that can satisfactorily correct various aberrations and has excellent optical performance. EXAMPLES

[0069] The zoom lens ZL according to the first and second embodiments of the present invention will be described below with reference to the drawings. Figures 1, 3, 5, and 7 are cross-sectional views showing the configuration of the zoom lens ZL {ZL(1)-ZL(4)} according to the first to fourth embodiments. The arrows at the bottom of these figures indicate the movement directions of the first to fifth lens groups G1-G5 and the aperture diaphragm S when zooming (variable magnification operation) from the wide-angle end state to the telephoto end state.

[0070] The fourth lens group G4 is used as a focusing lens, and in the figure, the direction of movement of this focusing lens when focusing from infinity to a close object is indicated by an arrow with the symbol "∞." Also, all or at least a part of the third lens group G3 is used as an image stabilizing lens having a displacement component perpendicular to the optical axis.

[0071] In these figures, each lens group is represented by a combination of a symbol G and a number, and each lens is represented by a combination of a symbol L and a number. In this case, in order to prevent the symbols and numbers from becoming too large and becoming complicated in number, the lens groups, etc. are represented by their own combinations of symbols and numbers for each embodiment. Therefore, even if the same combinations of symbols and numbers are used between embodiments, this does not mean that they have the same configuration.

[0072] Tables 1 to 4 are shown below, which are tables showing data of each element in the first to fourth examples.

[0073] In the [Lens specifications] table, the surface number indicates the order of the optical surfaces from the object side along the direction of light travel, R is the radius of curvature of each optical surface (surfaces whose center of curvature is located on the image side have a positive value), D is the surface spacing which is the distance on the optical axis from each optical surface to the next optical surface, nd is the refractive index of the optical component material with respect to the d line (wavelength 587.6 nm), and νd is the refractive index based on the d line of the optical component material. The Abbe number for each lens is indicated. The surface number indicates the order of the lens surface from the object side along the direction in which light travels. "∞" for the radius of curvature indicates a plane or an aperture, and (stop S) indicates the aperture stop S. The refractive index of air, nd = 1.00000, has been omitted. If the lens surface is aspheric, an * is added to the surface number, and the paraxial radius of curvature is indicated in the radius of curvature R column.

[0074] The [Overall Specifications] table shows the overall specifications of the zoom lens, where f is the focal length of the entire lens system, Fno. is the F-number, and ω is the half angle of view (maximum angle of incidence, in degrees). BF is infinity. It indicates the distance (back focus) from the last lens surface on the optical axis to the image plane I when in focus, TL is the total lens length, which indicates the distance from the frontmost lens surface on the optical axis to the last lens surface plus BF. Note that these values ​​are shown for each magnification state: wide-angle end state (Wide), intermediate focal length (Middle), and telephoto end state (Tele).

[0075] In the [Aspherical Data] table, the shape of the aspherical surface shown in [Lens Specifications] is shown by the following formula (a). X(y) is the distance (amount of sag) along the optical axis direction from the tangent plane at the apex of the aspherical surface to the position on the aspherical surface at height y, R is the radius of curvature of the reference sphere (paraxial radius of curvature), κ is the conic constant, and Ai is the ith aspherical coefficient. "En" is the ratio of "×10 -n For example, 1.234E-05=1.234×10 -5 In addition, the second-order aspheric coefficient A2 is 0, and is omitted.

[0076] X(y)=(y 2 / R) / {1+(1-κ×y 2 / R 2 ) 1 / 2}+A4×y 4 +A6×y 6 +A8×y 8 +A10×y 10 +A12×y 12 (a)

[0077] The [Variable Distance Data] table shows the surface distance Di to the next surface of surface number i, whose surface distance is "variable" in the [Lens Specifications] table. For example, in the first embodiment, The surface spacings D3, D9, D19, D21, and D23 are shown for the surfaces 3, 9, 19, 21, and 23. f indicates the focal length of the entire zoom lens system.

[0078] The table of [Lens Group Data] shows the surface numbers of the first surfaces (surfaces closest to the object) in the first to fourth (or fifth) lens groups, the focal length of each group, and the lens configuration length.

[0079] The table "Values ​​Corresponding to Conditional Expressions" shows values ​​corresponding to the above conditional expressions (1) to (7).

[0080] In the following, for all specifications, the focal length f, radius of curvature R, surface separation D, and other lengths are generally in "mm" unless otherwise specified; however, this is not limited to this because the optical system can provide the same optical performance even when proportionally enlarged or reduced.

[0081] The above is an explanation of matters common to all the embodiments, and duplicate explanations in each embodiment below will be omitted.

[0082] (First embodiment) The first embodiment will be described with reference to FIG. 1, FIG. 2, and Table 1. FIG. 1 is a diagram showing the lens configuration of a zoom lens ZL(1) according to the first embodiment of the present invention. This zoom lens ZL(1) is configured to include, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The sign (+) or (-) attached to each lens group symbol indicates the refractive power of each lens group. A filter FL is provided on the image side of the fifth lens group G5 and close to the image surface I. The filter FL is composed of a low-pass filter, an infrared cut filter, or the like. An aperture stop S is disposed on the object side of the third lens group G3. This aperture stop S is configured independently of the third lens group G3, but moves together with the third lens group G3 in the optical axis direction.

[0083] When varying the magnification, the first to fifth lens groups G1 to G5 each move in the axial direction as shown by the arrows in Figure 1. Therefore, the surface distances D3, D9, D19, D21, and D23 are variable, and the values ​​are shown in the [Variable Distance Data] table.

[0084] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (first surface) facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, arranged in order from the object side along the optical axis.

[0085] The second lens group G2 is composed of, arranged in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Both sides of the negative meniscus lens L21 are aspheric.

[0086] The third lens group is composed of, arranged in order from the object side along the optical axis, a biconvex positive lens L31, a negative meniscus lens L32 with its convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35. Both side surfaces of the positive lens L31 are aspheric.

[0087] The fourth lens group G4 is composed of a negative meniscus lens L41 with a convex surface facing the object side.

[0088] The fifth lens group G5 is composed of a positive meniscus lens L51 with its convex surface facing the object side. The object side surface of this positive meniscus lens L51 is aspheric.

[0089] In the zoom lens ZL(1), focusing from infinity (a long-distance object) to a close-distance object is performed by moving the fourth lens group G4 toward the image surface. In addition, all or at least a part of the third lens group G3 (which may be the entire third lens group G3, or any or a combination of the lenses L31 to L35 that constitute it) constitutes an anti-vibration lens group having a displacement component perpendicular to the optical axis, and performs image blur correction (anti-vibration, camera shake correction) on the image surface I.

[0090] Table 1 below lists the values ​​of the specifications of the optical system according to the first embodiment.

[0091] (Table 1) [Lens data] RD nd νd 1 39.599 0.940 1.9459 18.0 2 28.320 5.372 1.8348 42.7 3 161.160 (variable) 4* 121.431 1.074 1.7738 47.2 5* 11.074 6.715 6 -34.223 0.672 1.6968 55.5 7 76.259 0.134 8 30.756 2.283 1.9459 18.0 9 284.646 (variable) 10 ∞ 1.343 (Aperture S) 11* 14.154 3.828 1.8208 42.7 12* -49.429 0.134 13 36.789 0.940 1.6666 30.4 14 11.416 3.895 15 -16.584 0.672 1.9962 28.3 16 32.543 3.828 1.5928 68.6 17 -15.861 0.134 18 142.462 3.022 1.8040 46.6 19 -19.075 (variable) 20 168.862 0.672 1.6968 55.5 21 39.344 (variable) 22* 30.318 2.619 1.7725 49.5 23 87.295 (variable) 24 ∞ 3.700 1.5168 63.9 25∞(BF) Image plane ∞ [Overall specifications] Wide Middle Tele f 12.2 22.3 40.7 Aperture diameter 13.9 13.1 13.1 Fno. 1.9 2.4 2.8 ω 43.5 26.4 14.4 BF 0.99 0.99 0.99 Air equivalent BF 15.70 8.75 7.19 TL 82.94 83.68 100.11 Air equivalent TL 81.68 82.42 98.85 [Aspheric data] κ A4 A6 A8 A10 A12 4th side 1 -2.808E-05 2.147E-07 -7.556E-10 -2.372E-13 5.361E-15 5th side 1.052 -6.407E-05 -1.124E-08 -8.523E-09 1.324E-10 -1.141E-12 Page 11 0.026 1.201E-05 1.731E-07 0.000E+00 0.000E+00 0.000E+00 Side 12 1 7.117E-05 -9.785E-08 0.000E+00 0.000E+00 0.000E+00 22nd page 1 -7.376E-06 5.901E-08 -4.201E-10 1.361E-12 0.000E+00 [Variable interval data] Wide Middle Tele f 12.2 22.3 40.7 D3 0.935 6.724 19.177 D9 18.862 6.399 2.131 D19 2.015 10.154 4.509 D21 5.889 12.125 27.566 D23 12.274 5.321 3.761 [Zoom lens group data] Group number Group initial surface Group focal length Lens construction length G1 1 65.8 6.31 G2 4 -15.3 9.54 G3 11 20.5 17.79 G4 20 -73.8 0.67 G5 22 58.9 2.62 [Conditional expression corresponding value] Conditional expression (1) |MV5 / MV2|=7.94 Conditional expression (2) β2t / β2w =1.70 Conditional formula (3) |MV4 / MV2|=12.28 Condition (4) (β2t × β4w) / (β2w × β4t) = 1.59 Conditional expression (5) TLt / ft=2.46 Conditional expression (6) ωw=43.5 Conditional expression (7) ωt=14.4

[0092] As shown in the above table of [Conditional Expression Corresponding Values], the zoom lens ZL(1) according to the first example shown in FIG. 1 satisfies all of the above conditional expressions (1) to (7).

[0093] 2(a), 2(b), and 2(c) are diagrams showing various aberrations of the zoom lens ZL(1) according to the first embodiment when focusing on infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. As can be seen from each diagram, the zoom lens ZL(1) according to the first embodiment has excellent imaging performance by correcting various aberrations well from the wide-angle end state to the telephoto end state. Note that distortion aberrations can be corrected by image processing after image capture, and no optical correction is required.

[0094] In FIG. 2, FNO indicates the F-number, and ω indicates the half angle of view (unit: °) for each image height. d indicates the aberration at the d-line (λ = 587.6 nm), and g indicates the aberration at the g-line (λ = 435.8 nm). In the spherical aberration, astigmatism, and coma aberration diagrams, the solid lines indicate the sagittal aberration. The broken line indicates the aberration at the dotted line image plane, and the broken line indicates the aberration at the meridional image plane. This explanation is the same for all the aberration diagrams in the following examples, and therefore duplicated explanations will be omitted below.

[0095] (Second Example) The second example will be described with reference to FIG. 3, FIG. 4, and Table 2. FIG. 3 is a diagram showing the lens configuration of a zoom lens ZL(2) according to the second example of this embodiment. This zoom lens ZL(2) is configured to include, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. A filter FL is provided on the image side of the fifth lens group G5 and close to the image surface I. An aperture stop S is disposed on the object side of the third lens group G3. This aperture stop S is configured independently of the third lens group G3, but moves together with the third lens group G3 in the optical axis direction.

[0096] When varying the magnification, the first to fifth lens groups G1 to G5 each move in the axial direction as shown by the arrows in Fig. 3. Therefore, the surface distances D3, D9, D19, D21, and D23 are variable, and the values ​​are shown in the [Variable Distance Data] table.

[0097] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (first surface) facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, arranged in order from the object side along the optical axis.

[0098] The second lens group G2 is composed of, arranged in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Both sides of the negative meniscus lens L21 are aspheric.

[0099] The third lens group is composed of, arranged in order from the object side along the optical axis, a biconvex positive lens L31, a negative meniscus lens L32 with its convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35. Both side surfaces of the positive lens L31 and the positive lens L35 are aspheric.

[0100] The fourth lens group G4 is composed of a biconcave negative lens L41.

[0101] The fifth lens group G5 is composed of a positive meniscus lens L51 having a convex surface facing the object side, the object side surface of which is aspheric.

[0102] In the zoom lens ZL(2), focusing from infinity (a long-distance object) to a close-distance object is performed by moving the fourth lens group G4 toward the image surface. In addition, all or at least a part of the third lens group G3 constitutes an anti-vibration lens group having a displacement component in a direction perpendicular to the optical axis, and performs image blur correction (anti-vibration, camera shake correction) on the image surface I.

[0103] Table 2 below lists the values ​​of the specifications of the optical system according to the second embodiment.

[0104] (Table 2) [Lens data] RD nd νd 1 36.635 1.074 1.9460 18.0 2 28.013 5.372 1.8040 46.6 3 114.144 (variable) 4* 87.223 1.074 1.8514 40.1 5* 11.136 6.849 6 -42.800 0.672 1.6968 55.5 7 58.836 0.134 8 29.612 2.552 2.0027 19.3 9 677.090 (variable) 10 ∞ 1.343 (Aperture S) 11* 14.440 3.760 1.7433 49.3 12* -172.482 0.134 13 13.667 2.283 1.7950 28.7 14 9.434 3.358 15 -17.037 0.672 1.7552 27.6 16 13.246 3.492 1.4970 81.7 17 -55.668 0.134 18* 28.527 3.358 1.7725 49.6 19* -16.687 (variable) 20 -131.120 0.806 1.6030 65.4 21 32.989 (variable) 22* 25.536 4.029 1.6935 53.2 23 277.466 (variable) 24 ∞ 1.350 1.5168 63.9 25∞(BF) Image plane ∞ [Overall specifications] Wide Middle Tele f 12.2 22.3 40.7 Aperture diameter 13.6 10.8 12.9 Fno. 1.9 2.9 2.9 ω 42.6 26.1 14.4 BF 2.54 2.54 2.54 Air equivalent BF 12.08 7.23 6.54 TL 80.65 81.66 98.48 Air equivalent TL 80.19 81.20 98.02 [Aspheric data] κ A4 A6 A8 A10 A12 4th side 1 -2.244E-05 2.093E-08 1.088E-09 -7.741E-12 1.640E-14 5th side 0.957 -5.462E-05 -1.346E-07 -7.444E-09 1.180E-10 -8.246E-13 Side 11 1.121 -3.990E-05 -1.142E-07 0.000E+00 0.000E+00 0.000E+00 12th side 1 -7.117E-06 1.245E-07 0.000E+00 0.000E+00 0.000E+00 Side 18 1 -4.823E-05 1.325E-07 0.000E+00 0.000E+00 0.000E+00 Page 19 1 1.580E-05 -6.115E-08 0.000E+00 0.000E+00 0.000E+00 Side 22 1 -8.610E-06 9.380E-08 -5.728E-10 1.509E-12 0.000E+00 [Variable interval data] Wide Middle Tele f 12.2 22.3 40.7 D3 0.824 7.259 20.119 D9 19.217 6.624 2.015 D19 2.015 6.335 2.952 D21 4.966 12.657 25.303 D23 8.650 3.800 3.114 [Zoom lens group data] Group number Group initial surface Group focal length Lens construction length G1 1 69.8 6.45 G2 4 -16.9 11.28 G3 11 19.7 17.19 G4 20 -43.6 0.81 G5 22 40.3 4.03 [Conditional expression corresponding value] Conditional expression (1) |MV5 / MV2|=3.78 Conditional expression (2) β2t / β2w =1.70 Conditional formula (3) |MV4 / MV2|=10.10 Conditional formula (4) (β2t × β4w) / (β2w × β4t) = 1.51 Conditional expression (5) TLt / ft=2.42 Conditional expression (6) ωw=42.6 Conditional expression (7) ωt=14.4

[0105] As shown in the above table of [Conditional Expression Corresponding Values], the zoom lens ZL(2) according to the second example shown in FIG. 3 satisfies all of the above conditional expressions (1) to (7).

[0106] 4(a), 4(b), and 4(c) are diagrams showing various aberrations of the zoom lens ZL(2) according to Example 2 when focused on infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. As can be seen from each diagram, the zoom lens ZL(2) according to Example 2 satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state, and has excellent imaging performance.

[0107] (Third Example) The third example will be described with reference to FIG. 5, FIG. 6, and Table 3. FIG. 5 is a diagram showing the lens configuration of a zoom lens ZL(3) according to the third example of this embodiment. This zoom lens ZL(3) is configured to include, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. A filter FL is provided on the image side of the fifth lens group G5 and close to the image surface I. An aperture stop S is disposed on the object side of the third lens group G3. This aperture stop S is configured independently of the third lens group G3, but moves together with the third lens group G3 in the optical axis direction.

[0108] When varying the magnification, the first to fifth lens groups G1 to G5 each move in the axial direction as shown by the arrows in Fig. 5. For this reason, the surface distances D3, D9, D19, D21, and D23 are variable, and the values ​​are shown in the [Variable Distance Data] table.

[0109] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface (first surface) facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, arranged in order from the object side along the optical axis.

[0110] The second lens group G2 is composed of, arranged in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Both sides of the negative meniscus lens L21 are aspheric.

[0111] The third lens group is composed of, arranged in order from the object side along the optical axis, a biconvex positive lens L31, a negative meniscus lens L32 with its convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35. Both sides of the positive lens L31 and the positive lens L35 are aspheric.

[0112] The fourth lens group G4 is composed of a biconcave negative lens L41.

[0113] The fifth lens group G5 is composed of a positive meniscus lens L51 having a convex surface facing the object side, the object side surface of which is aspheric.

[0114] In the zoom lens ZL(3), focusing from infinity (a long-distance object) to a close-distance object is performed by moving the fourth lens group G4 toward the image surface. In addition, all or at least a part of the third lens group G3 constitutes an anti-vibration lens group having a displacement component in a direction perpendicular to the optical axis, and performs image blur correction (anti-vibration, camera shake correction) on the image surface I.

[0115] Table 3 below lists the values ​​of the specifications of the optical system according to the third embodiment.

[0116] (Table 3) [Lens data] RD nd νd 1 35.049 1.074 2.0027 19.3 2 25.373 5.641 1.8348 42.7 3 110.958 (variable) 4* 188.807 1.074 1.7738 47.2 5* 10.397 6.446 6 -39.303 0.672 1.6968 55.5 7 55.370 0.134 8 29.024 2.485 2.0027 19.3 9 1027.710 (variable) 10 ∞ 1.343 (Aperture S) 11* 13.928 3.492 1.7433 49.3 12* -96.886 0.134 13 15.453 1.209 1.8081 22.7 14 10.080 3.895 15 -13.665 0.672 2.0010 29.1 16 53.442 2.887 1.4970 81.7 17 -19.734 0.134 18* 55.578 3.828 1.7725 49.5 19* -14.278 (variable) 20 -5325.655 0.806 1.6030 65.4 21 35.704 (variable) 22* 27.530 3.358 1.6935 53.2 23 158.402 (variable) 24∞ 3.210 1.5168 63.9 25∞(BF) Image plane ∞ [Overall specifications] Wide Middle Tele f 12.2 22.3 40.7 Aperture diameter 13.4 10.6 13.4 Fno. 1.9 2.9 2.8 ω 42.6 26.1 14.4 BF 1.31 1.31 1.31 Air equivalent BF 15.72 7.18 5.78 TL 82.18 83.99 101.28 Air equivalent TL 81.08 82.90 100.19 [Aspheric data] κ A4 A6 A8 A10 A12 4th side 1 -1.006E-05 -1.100E-07 2.367E-09 -1.481E-11 3.218E-14 5th side 0.983 -5.867E-05 -1.605E-07 -1.814E-08 3.047E-10 -2.240E-12 Page 11 -1.173 5.293E-05 -1.532E-07 0.000E+00 0.000E+00 0.000E+00 Side 12 1 -2.009E-06 9.410E-08 0.000E+00 0.000E+00 0.000E+00 Side 18 1 -4.273E-05 7.466E-08 0.000E+00 0.000E+00 0.000E+00 Page 19 1 2.000E-05 3.680E-09 0.000E+00 0.000E+00 0.000E+00 22nd page 1 -6.307E-06 4.267E-08 -3.049E-10 1.360E-12 0.000E+00 [Variable interval data] Wide Middle Tele f 12.2 22.3 40.7 D3 1.235 7.127 19.303 D9 17.677 6.273 2.594 D19 2.015 10.446 4.847 D21 5.150 12.586 28.387 D23 12.296 3.753 2.349 [Zoom lens group data] Group number Group initial surface Group focal length Lens construction length G1 1 65.8 6.72 G2 4 -15.6 10.81 G3 11 20.4 17.59 G4 20 -58.8 0.81 G5 22 47.5 3.36 [Conditional expression corresponding value] Conditional expression (1) |MV5 / MV2|=9.57 Conditional expression (2) β2t / β2w =1.71 Conditional formula (3) |MV4 / MV2|=12.78 Conditional formula (4) (β2t × β4w) / (β2w × β4t) = 1.64 Conditional expression (5) TLt / ft=2.49 Conditional expression (6) ωw=42.6 Conditional expression (7) ωt=14.4

[0117] As shown in the above table of [Conditional Expression Corresponding Values], the zoom lens ZL(3) according to the third example shown in FIG. 5 satisfies all of the above conditional expressions (1) to (7).

[0118] 6(a), 6(b), and 6(c) are diagrams showing various aberrations of the zoom lens ZL(3) according to Example 3 when focusing on infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. As can be seen from each diagram, the zoom lens ZL(3) according to Example 2 has excellent imaging performance, with various aberrations being well corrected from the wide-angle end state to the telephoto end state.

[0119] (Fourth Example) The fourth example will be described with reference to FIG. 7, FIG. 8 and Table 4. FIG. 7 is a diagram showing the lens configuration of a zoom lens ZL(4) according to the fourth example of this embodiment. This zoom lens ZL(4) is configured to include, arranged in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. A filter FL is provided on the image side of the fifth lens group G5 and close to the image surface I. An aperture stop S is disposed inside the third lens group G3.

[0120] When varying the magnification, the first to fifth lens groups G1 to G5 each move in the axial direction as shown by the arrows in Fig. 7. Therefore, the surface distances D3, D9, D19, D21, and D24 are variable, and the values ​​are shown in the [Variable Distance Data] table.

[0121] The first lens group G1 is composed of a cemented lens of a negative meniscus lens L11 with a convex surface facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, arranged in order from the object side along the optical axis.

[0122] The second lens group G2 is composed of, arranged in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a biconvex positive lens L23. Both side surfaces of the negative meniscus lens L21 are aspheric.

[0123] The third lens group is composed of, arranged in order from the object side along the optical axis, a biconvex positive lens L31, a negative meniscus lens L32 with its convex surface facing the object side, a cemented lens of a biconcave negative lens L33 and a biconvex positive lens L34, and a biconvex positive lens L35. Both sides of the positive lens L31 and the positive lens L35 are aspheric.

[0124] The fourth lens group G4 is composed of a negative meniscus lens L41 with a convex surface facing the object side.

[0125] The fifth lens group G5 is composed of, arranged in order from the object side along the optical axis, a biconvex positive lens L51 and a negative meniscus lens L52 with its convex surface facing the image side.

[0126] In the zoom lens ZL(4), focusing from infinity (long-distance object) to a close-distance object is performed by moving the fourth lens group G4 toward the image surface. In addition, all or at least a part of the third lens group G3 constitutes an anti-vibration lens group having a displacement component in a direction perpendicular to the optical axis, and performs image blur correction (anti-vibration, camera shake correction) on the image surface I.

[0127] Table 4 below lists the values ​​of the specifications of the optical system according to the fourth embodiment.

[0128] (Table 4) [Lens data] RD nd νd 1 51.721 2.015 1.8467 23.8 2 40.614 7.055 1.6030 65.4 3 730.595 (variable) 4* 366.053 2.015 1.7725 49.5 5* 15.152 9.651 6 -33.575 1.343 1.6030 65.4 7 5551.208 0.271 8 52.110 2.820 1.8467 23.8 9 -4156.714 (variable) 10* 23.190 5.883 1.7725 49.5 11* -75.540 2.015 12 ∞ 2.015 (Aperture S) 13 118.818 0.940 1.7380 32.3 14 19.813 5.874 15 -14.724 0.940 1.7380 32.3 16 33.575 6.464 1.8040 46.6 17 -21.843 0.134 18* 29.197 5.666 1.5533 71.7 19* -30.869 (variable) 20 83.361 1.343 1.4875 70.1 21 28.987 (variable) 22 29.079 6.044 1.6030 65.4 23 -42.616 1.074 1.8467 23.8 24 -594.734 (variable) 25∞ 1.500 1.5168 63.8 26∞(BF) Image plane ∞ [Overall specifications] Wide Middle Tele f 12.2 22.2 40.6 Aperture diameter 18.6 18.6 18.6 Fno. 1.4 1.7 2.2 ω 42.8 26.7 14.5 BF 1.69 1.69 1.69 Air equivalent BF 12.92 9.00 4.69 TL 114.12 111.74 135.04 Air equivalent TL 113.61 111.23 134.53 [Aspheric data] κ A4 A6 A8 A10 4th side 1 -1.006E-05 -1.100E-07 2.367E-09 -1.481E-11 5th side 0.983 -5.867E-05 -1.605E-07 -1.814E-08 3.047E-10 10th side -1.173 5.293E-05 -1.532E-07 0.000E+00 0.000E+00 Page 11 1 -2.009E-06 9.410E-08 0.000E+00 0.000E+00 Side 18 1 -4.273E-05 7.466E-08 0.000E+00 0.000E+00 Page 19 1 2.000E-05 3.680E-09 0.000E+00 0.000E+00 [Variable interval data] Wide Middle Tele f 12.2 22.2 40.6 D3 0.537 9.250 23.503 D9 27.283 6.864 0.672 D19 1.672 8.741 1.637 D21 7.632 13.813 40.473 D24 10.249 6.327 2.015 [Zoom lens group data] Group number Group initial surface Group focal length Lens construction length G1 1 103.0 9.07 G2 4 -20.1 16.10 G3 10 28.0 29.93 G4 20 -91.9 1.34 G5 22 59.6 7.12 [Conditional expression corresponding value] Conditional expression (1) |MV5 / MV2|=4.04 Conditional expression (2) β2t / β2w =1.44 Conditional formula (3) |MV4 / MV2|=12.07 Conditional formula (4) (β2t × β4w) / (β2w × β4t) = 1.25 Conditional expression (5) TLt / ft=3.32 Conditional expression (6) ωw=42.8 Conditional expression (7) ωt=14.5

[0129] As shown in the above table of [Conditional Expression Corresponding Values], the zoom lens ZL(4) according to the fourth example shown in FIG. 7 satisfies all of the above conditional expressions (1) to (7).

[0130] 8(a), 8(b), and 8(c) are diagrams showing various aberrations of the zoom lens ZL(4) according to Example 4 when focused on infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. As can be seen from each diagram, the zoom lens ZL(4) according to Example 2 satisfactorily corrects various aberrations from the wide-angle end state to the telephoto end state, and has excellent imaging performance.

[0131] The above-mentioned embodiments are merely examples of the present invention, and the present invention is not limited to these.

[0132] The following contents can be appropriately adopted within the scope that does not impair the optical performance of the zoom lens of this embodiment.

[0133] Although a five-group configuration has been shown as an example of the zoom lens of this embodiment, the present application is not limited to this, and a zoom lens of other group configurations (for example, six groups, etc.) can also be configured. Specifically, a lens or lens group may be added to the most object side or the most image side of the zoom lens of this embodiment. Note that a lens group refers to a portion having at least one lens separated by an air gap that changes when changing magnification.

[0134] A single or multiple lens groups, or a partial lens group, may be moved in the optical axis direction to form a focusing lens group that focuses from an object at infinity to an object at a close distance. The focusing lens group may also be applied to autofocus, and may be driven by a motor (using an ultrasonic motor, etc.) for autofocus. Suitable.

[0135] The lens group or partial lens group may be moved so as to have a component in a direction perpendicular to the optical axis, or may be rotated (rocked) in a plane including the optical axis to serve as an anti-vibration lens group that corrects image blur caused by camera shake.

[0136] The lens surface may be spherical or flat, or aspherical. A spherical or flat lens surface is preferable because it facilitates lens processing and assembly adjustment, and prevents deterioration of optical performance due to errors in processing and assembly adjustment. It is also preferable because there is little deterioration in image quality even if the image plane is shifted.

[0137] When the lens surface is aspheric, the aspheric surface may be any of the following: an aspheric surface formed by grinding, a glass molded aspheric surface formed by molding glass into an aspheric shape, or a composite aspheric surface formed by molding a resin into an aspheric shape on the surface of glass. The lens surface may also be a diffractive surface, or the lens may be a gradient index lens (GRIN lens) or a plastic lens.

[0138] It is preferable that the aperture diaphragm is disposed near or within the third lens group, but it is also possible to use the lens frame to fulfill that role instead of providing a member serving as an aperture diaphragm.

[0139] Each lens surface may be coated with an anti-reflection coating having high transmittance over a wide wavelength range in order to reduce flare and ghosting and achieve high-contrast optical performance.

[0140] The zoom lens of this embodiment has a magnification ratio of about 1.5 to 7.5. [Explanation of symbols]

[0141] G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group FL filter I Image plane S Aperture stop

Claims

1. The optical system substantially comprises five lens groups, which are arranged in order from the object side along the optical axis, namely, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power; When changing magnification from the wide-angle end state to the telephoto end state, the spacing between adjacent lens groups changes. When changing magnification from the wide-angle end state to the telephoto end state, the first lens group moves toward the object side, the first lens group includes a cemented lens of a negative lens and a positive lens arranged in order from the object side along an optical axis, the third lens group has at least two positive single lenses, a cemented lens of a negative lens and a positive lens arranged in order from the object side, and the positive single lens is disposed closest to the object side; the fourth lens group has a negative single lens, the fifth lens group has a positive single lens, A zoom lens characterized by satisfying the following conditional expressions: 2.90<|MV5 / MV2|<11.50 0.10<(β2t × β4w) / (β2w × β4t)<2.40 where MV5 is the amount of movement of the fifth lens group relative to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the fifth lens group corresponds to the distance between the position of the fifth lens group in the wide-angle end state and the position of the fifth lens group in the telephoto end state). MV2: the amount of movement of the second lens group based on the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the second lens group corresponds to the distance between the position of the second lens group in the wide-angle end state and the position of the second lens group in the telephoto end state) βt: the magnification of the second lens group in the telephoto end state β2w: the magnification of the second lens group in the wide-angle end state β4t: Magnification of the fourth lens group in the telephoto end state β4w: the magnification of the fourth lens group in the wide-angle end state

2. The optical system substantially comprises five lens groups, which are arranged in order from the object side along the optical axis, namely, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power; When changing magnification from the wide-angle end state to the telephoto end state, the spacing between adjacent lens groups changes. When changing magnification from the wide-angle end state to the telephoto end state, the first lens group moves toward the object side, during zooming from the wide-angle end state to the telephoto end state, a position of the second lens group in the telephoto end state is closer to the image surface side than a position of the second lens group in the wide-angle end state, and a position of the fifth lens group in the telephoto end state is closer to the image surface side than a position of the fifth lens group in the wide-angle end state; the first lens group includes a cemented lens of a negative lens and a positive lens arranged in order from the object side along an optical axis, the third lens group has at least two positive single lenses, the positive single lens being disposed closest to the object side; the fifth lens group has a positive single lens, A zoom lens characterized by satisfying the following conditional expressions: 3.78≦|MV5 / MV2|≦7.94 where MV5 is the amount of movement of the fifth lens group relative to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the fifth lens group corresponds to the distance between the position of the fifth lens group in the wide-angle end state and the position of the fifth lens group in the telephoto end state). MV2: the amount of movement of the second lens group based on the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the second lens group corresponds to the distance between the position of the second lens group in the wide-angle end state and the position of the second lens group in the telephoto end state)

3. 3. The zoom lens according to claim 1, wherein the following condition is satisfied: 6.00<|MV4 / MV2|<15.00 where MV4 is the amount of movement of the fourth lens group relative to the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the fourth lens group corresponds to the distance between the position of the fourth lens group in the wide-angle end state and the position of the fourth lens group in the telephoto end state). MV2: the amount of movement of the second lens group based on the image plane when changing magnification from the wide-angle end state to the telephoto end state (the amount of movement of the second lens group corresponds to the distance between the position of the second lens group in the wide-angle end state and the position of the second lens group in the telephoto end state)

4. 3. The zoom lens according to claim 2, wherein the third lens group comprises a cemented lens of a negative lens and a positive lens, arranged in order from the object side along the optical axis.

5. 3. The zoom lens according to claim 1, wherein the second lens group comprises a single positive lens.

6. 6. The zoom lens according to claim 2, wherein the fourth lens group has a negative single lens.

7. 7. The zoom lens according to claim 1, wherein the fifth lens group moves toward the image side during zooming from the wide-angle end state to the telephoto end state.

8. 8. The zoom lens according to claim 1, wherein the following condition is satisfied: 1.50<TLt / ft<5.00 where TLt is the total length of the zoom lens in the telephoto end state. ft: focal length of entire zoom lens at telephoto end

9. 9. The zoom lens according to claim 1, wherein the following condition is satisfied: 1.20<β2t / β2w<2.50 where β2t is the magnification of the second lens group in the telephoto end state. β2w: the magnification of the second lens group in the wide-angle end state

10. 10. The zoom lens according to claim 2, wherein the following condition is satisfied: 0.10<(β2t × β4w) / (β2w × β4t)<2.40 where β2t is the magnification of the second lens group in the telephoto end state. β2w: the magnification of the second lens group in the wide-angle end state β4t: Magnification of the fourth lens group in the telephoto end state β4w: the magnification of the fourth lens group in the wide-angle end state

11. 11. The zoom lens according to claim 1, wherein the following condition is satisfied: 5.0<ωt<25.0 Where ωt: half angle of view of the entire zoom lens in the telephoto end state (unit: degree)

12. 12. The zoom lens according to claim 1, wherein the following condition is satisfied: 28.0<ωw<65.0 Where ωt: half angle of view of the entire zoom lens in the wide-angle end state (unit: degree)

13. 13. The zoom lens according to claim 1, wherein at least a part of the fourth lens group is a focusing lens.

14. 14. The zoom lens according to claim 1, wherein at least a part of the third lens group has a displacement component in a direction perpendicular to the optical axis.

15. An optical device comprising the zoom lens according to any one of claims 1 to 14.

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