Zoom lens and image pickup apparatus

Abstract

The present disclosure relates to a zoom lens and an image pickup apparatus. The zoom lens includes, in order from an object side toward an image side, a first lens unit having positive refractive power, a plurality of zoom lens units configured to move along an optical axis in zooming and including a lens unit having negative refractive power, and a last lens unit having positive refractive power. Distances between each pair of adjacent lens units change in zooming. The first lens unit includes, in order from the object side toward the image side, a first sub-unit having negative refractive power, a second sub-unit having negative refractive power, and at least one subsequent sub-unit, wherein distances between each pair of adjacent sub-units change for focus adjustment, the second sub-unit is configured to move along the optical axis for focus adjustment. A predetermined condition is satisfied.

Description

Technical Field

[0001] This invention relates to zoom lenses and camera equipment. Background Technology

[0002] Because imaging devices such as CCD and CMOS used in TV cameras and movie cameras have high resolution across the entire imaging range, zoom lenses used in these cameras are required to have high resolution from the center to the periphery of the image. Furthermore, to reduce the number of illumination devices, zoom lenses are required to have shallow depth of field and large aperture diameter.

[0003] Japanese Patent Application Publication No. 2004-309761 discloses a positive lead type zoom lens with a 2 / 3 format for broadcasting, a zoom ratio of approximately 3x, and an f-number of approximately 1.5. The positive lead type zoom lens disclosed in JP2004-309761 includes, in order from the object side, a first lens unit to a fourth lens unit having positive refractive power, negative refractive power, positive refractive power or negative refractive power, and positive refractive power, and an aperture stop arranged on the object side of the fourth lens unit. In the zoom lens disclosed in JP2004-309761, the first lens unit is fixed relative to the image plane during zooming. In the zoom lens disclosed in JP2004-309761, the first lens unit includes, in order from the object side, a first sub-unit to a third sub-unit having negative refractive power, negative refractive power, and positive refractive power, and has an internal focusing structure where the second sub-unit is responsible for focusing.

[0004] The lens diameter of the lens unit closest to the object in the first lens unit is determined by the off-axis rays at the wide-angle end, and the lens diameter of the lens unit closest to the image plane in the first lens unit is determined by the on-axis rays at the telephoto end. Therefore, in order to increase the aperture diameter, the zoom lens becomes larger as the first lens unit becomes thicker. In the zoom lens disclosed in JP2004-309761, the first lens unit is thick, thus the zoom lens becomes larger when dealing with large sensors such as Super 35 format and full-frame format while maintaining the F-number. Summary of the Invention

[0005] The present disclosure provides zoom lenses that are advantageous in terms of large aperture, small size and light weight, and have high optical performance throughout their zoom range.

[0006] A zoom lens according to one aspect of the present invention includes, in order from the object side to the image side: a first lens unit having a positive refractive power; a plurality of zoom lens units configured to move along the optical axis during zooming and including a lens unit having a negative refractive power; and a last lens unit having a positive refractive power, wherein the distance between each pair of adjacent lens units changes during zooming, and is characterized in that the first lens unit includes, in order from the object side to the image side: a first subunit having a negative refractive power, a second subunit having a negative refractive power, and at least one subsequent subunit, wherein the distance between each pair of adjacent subunits changes for focusing, wherein the second subunit is configured to move along the optical axis for focusing, and wherein the following inequality is satisfied: 0.20 < f1R / f1 < 1.10, where f1R is the focal length of the at least one subsequent subunit in a state of focusing at infinity, and f1 is the focal length of the first lens unit in the state of focusing at infinity.

[0007] An imaging device according to another aspect of the present invention includes: the above-mentioned zoom lens; and an image sensor configured to capture an image formed by the zoom lens.

[0008] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a cross-sectional view of the zoom lens according to Example 1 in a state of focusing at infinity (focusing on an object at infinity) at the wide-angle end.

[0010] Figure 2A 、 2B and 2C are longitudinal aberration diagrams of the zoom lens according to Example 1 in a state of focusing at infinity at the wide-angle end, at a focal length of 70 mm, and at the telephoto end, respectively.

[0011] Figure 3A and 3B are optical path diagrams of light rays passing through the first lens unit in the zoom lens according to Example 1 in a state of focusing at infinity at the wide-angle end and at the telephoto end, respectively.

[0012] Figure 4 is a cross-sectional view of the zoom lens according to Example 2 in a state of focusing at infinity at the wide-angle end.

[0013] Figure 5A 、 5B and 5C are longitudinal aberration diagrams of the zoom lens according to Example 2 in a state of focusing at infinity at the wide-angle end, at a focal length of 65 mm, and at the telephoto end in Example 1, respectively.

[0014] Figure 6 This is a cross-sectional view of the zoom lens according to Example 3, at the wide-angle end and focused at infinity.

[0015] Figure 7A , 7B 7C and 7C are the longitudinal aberration diagrams of the zoom lens according to Example 3 at the wide-angle end, at a focal length of 38mm, and at the telephoto end with the lens focused at infinity.

[0016] Figure 8 This is a cross-sectional view of the zoom lens in Example 4, where it is focused at infinity at the wide-angle end.

[0017] Figure 9A , 9B 9C and 9C are the longitudinal aberration diagrams of the zoom lens according to Example 4 at the wide-angle end, at a focal length of 85mm, and at the telephoto end with the lens focused at infinity.

[0018] Figure 10 This is a cross-sectional view of the zoom lens according to Example 5, at the wide-angle end and focused at infinity.

[0019] Figure 11A , 11B 11C and 11C are the longitudinal aberration diagrams of the zoom lens according to Example 5 at the wide-angle end, at a focal length of 70mm, and at the telephoto end with the lens focused at infinity.

[0020] Figure 12 This is a cross-sectional view of the zoom lens according to Example 6, at the wide-angle end and focused at infinity.

[0021] Figure 13A , 13B 13C and 13C are the longitudinal aberration diagrams of the zoom lens according to Example 6 at the wide-angle end, at a focal length of 104mm, and at the telephoto end with the lens focused at infinity.

[0022] Figure 14 This is a cross-sectional view of the zoom lens according to Example 7, at the wide-angle end and focused at infinity.

[0023] Figure 15A , 15B The figures for 15C are the longitudinal aberration diagrams of the zoom lens according to Example 7 at the wide-angle end, at a focal length of 80mm, and at the telephoto end with the lens focused at infinity.

[0024] Figure 16 This is a cross-sectional view of the zoom lens according to Example 8, at the wide-angle end with the lens focused at infinity.

[0025] Figure 17A , 17B17C and 17C are the longitudinal aberration diagrams of the zoom lens according to Example 8 at the wide-angle end, at a focal length of 170mm, and at the telephoto end with the lens focused at infinity.

[0026] Figure 18 This is a cross-sectional view of the zoom lens according to Example 9, at the wide-angle end and focused at infinity.

[0027] Figure 19A , 19B 19C and 19C are longitudinal aberration diagrams of the zoom lens according to Example 9 at the wide-angle end, at a focal length of 73mm, and at the telephoto end with the lens focused at infinity.

[0028] Figure 20 This is a schematic diagram of the camera equipment. Detailed Implementation

[0029] A detailed description of embodiments of the present invention will now be given with reference to the accompanying drawings. The same reference numerals are assigned to corresponding elements in the figures, and repeated descriptions will be omitted.

[0030] Figure 1 , 4 Figures 6, 8, 10, 12, 14, 16, and 18 are cross-sectional views of the zoom lenses of Examples 1 to 9 in the wide-angle end, focused at infinity (focused on an object at infinity) (or infinity-focused state). The zoom lenses of each example are used in imaging equipment such as digital video cameras, digital still cameras, broadcast cameras, film-based cameras, and surveillance cameras.

[0031] In the various cross-sectional views, the left side is the object side, and the right side is the image side. The zoom lenses according to the various examples include multiple lens units. In this description, a lens unit is a group of lenses that moves or remains stationary during zooming (magnification). That is, in the zoom lenses according to the various examples, the distances between adjacent lens units are changed during zooming. The arrows shown in the various cross-sectional views indicate the direction of movement of the lens units during zooming from the wide-angle end to the telephoto end. A lens unit may include one or more lenses. A lens unit may include an aperture stop (opening aperture). Wide-angle end and telephoto end refer to the zoom positions when the second lens unit L2, which will be described below, is located at the two ends of the movable range during zooming.

[0032] In each cross-sectional view, Li represents the i-th lens unit (i is a natural number) counting from the object side among the lens units included in the zoom lens.

[0033] SP stands for aperture stop (opening aperture). I stands for image plane, and in cases where the zoom lens according to the various examples is used as an imaging optical system for a digital still camera or a digital video camera, the imaging plane of a solid-state image sensor (imaging element or photoelectric conversion element), such as a CCD sensor or a CMOS sensor, is disposed here. In cases where the zoom lens according to the various examples is used as an imaging optical system for a film-based camera, the photosensitive surface corresponding to the film plane is disposed on image plane I.

[0034] Figure 2A , 5A 7A, 9A, 11A, 13A, 15A, 17A and 19A are the longitudinal aberration diagrams at the wide-angle end of the zoom lenses according to Examples 1 to 9. Figure 2B , 5B 7B, 9B, 11B, 13B, 15B, 17B and 19B are longitudinal aberration diagrams for focal lengths of 70, 65, 38, 85, 70, 104, 80, 170 and 73mm respectively, based on the zoom lenses of Examples 1 to 9. Figure 2C , 5C 7C, 9C, 11C, 13C, 15C, 17C, and 19C are longitudinal aberration diagrams at the telephoto end for the zoom lenses according to Examples 1 to 9. Each aberration diagram shows the longitudinal aberration at infinity. Spherical aberration is shown in the range of ±0.400mm, astigmatism in the range of ±0.400mm, distortion in the range of ±10.000%, and lateral chromatic aberration in the range of ±0.100mm.

[0035] In spherical aberration, Fno represents the F-value and indicates the amount of spherical aberration for the e-line (wavelength 546.1 nm) and g-line (wavelength 435.8 nm). In the astigmatism diagram, M represents the amount of astigmatism on the meridional plane, and S represents the amount of astigmatism on the sagittal plane. The distortion diagram shows the distortion for the e-line. The chromatic aberration diagram shows the amount of chromatic aberration for the g-line. ω is the half-viewing angle (°).

[0036] Next, the characteristic structure of the zoom lens based on each example will be explained.

[0037] The present invention can provide a small and lightweight zoom lens with an F-number of about 1.4 to 3, a zoom ratio of about 2 to 4x, and high optical performance throughout the zoom range.

[0038] The zoom lens according to various examples includes, in order from the object side to the image side, a first lens unit L1 having positive refractive power; a plurality of zoom lens units having negative refractive power, configured to move along the optical axis during zooming and having negative refractive power; and a final lens unit having positive refractive power. In the zoom lens according to various examples, the distances between adjacent lens units are changed during zooming.

[0039] In various examples, the first lens unit L1 is fixed during zooming (or does not move for zooming), but at least one sub-unit included in the first lens unit L1 is movable.

[0040] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a subsequent sub-unit (also referred to as "at least one subsequent sub-unit") L1R. The second sub-unit L12 moves along the optical axis during focusing.

[0041] The zoom lenses in each example satisfy the following inequality (conditional expression) (1).

[0042] 0.20 <f1R / f1<1.10 (1)

[0043] Wherein, f1R is the focal length of the subsequent sub-unit (at least one subsequent sub-unit) L1R in the state of focusing at infinity, and f1 is the focal length of the first lens unit L1 in the state of focusing at infinity.

[0044] For reference Figure 3A and Figure 3B The optical behavior of the first lens unit L1, which has a structure according to various examples, will be described. Figure 3A and Figure 3BThese are the optical path diagrams of the light rays passing through the first lens unit L1 in the zoom lens of Example 1, focused at infinity at both the wide-angle and telephoto ends. As described above, the second sub-unit L12 moves along the optical axis during focusing. The lens diameter of the first sub-unit L11, which has the largest lens diameter among the lens units included in the first lens unit L1, is determined by the off-axis beam focused at infinity at the telephoto end. Therefore, when pursuing a larger aperture diameter, the first sub-unit L11 may become larger to ensure sufficient peripheral illumination ratio at the wide-angle end. The lens diameter of the third sub-unit L13, which is the subsequent sub-unit L1R, is determined by the on-axis beam used to determine the F-value focused at infinity at the telephoto end. When pursuing a larger aperture diameter, the lens diameter of the third sub-unit L13 may become larger. Therefore, this example appropriately sets the focal length of the subsequent subunit L1R and reduces the amount of movement of the second subunit L12 during focusing, thereby making the first lens unit L1 thinner and suppressing the increase in the diameter of the first subunit L11 associated with a larger aperture diameter.

[0045] In the zoom lens according to the various examples, the sensitivity ES of the second subunit L12, which is a focusing unit that can be moved during focusing, can be expressed by the following equation.

[0046] ES=(1-β12 2 )β13 2 β2 2 …βn 2

[0047] Wherein, β12 is the lateral magnification of the second subunit L12, and β13, β2 and βn are the lateral magnifications of the subsequent subunit L1R, the second lens unit L2 and the lens unit arranged on the image side of the second lens unit L2, respectively.

[0048] The greater the sensitivity ES, the smaller the amount of movement of the second subunit L12 from an infinity object to a shorter distance object. According to the above expression, with the focal length of the zoom lens and the first lens unit L1 fixed, the sensitivity ES can be increased by decreasing the lateral magnification β12 and by increasing the lateral magnification β13. According to the zoom lens in the various examples, the lateral magnification β12 can be decreased and the lateral magnification β13 increased by decreasing the focal length of the subsequent subunit L1R. Because the amount of movement of the second subunit L12 during focusing can be reduced, and the thickness of the first lens unit L1 can be reduced, the increase in the lens diameter of the first subunit L11 as the aperture diameter increases can be suppressed.

[0049] Inequality (1) defines the ratio of the focal length of the subsequent subunit L1R to the focal length of the first lens unit L1. Reducing the focal length of the subsequent subunit L1R also reduces the focal length of the second subunit L12. Therefore, the lateral magnification β12 of the second subunit L12 can be reduced, the lateral magnification β1R of the subsequent subunit L1R can be increased, and the amount of movement of the second subunit L12 during focusing can be reduced. That is, satisfying inequality (1) allows the zoom lens to be small and provides high optical performance. When the ratio of the focal length of the subsequent subunit L1R to the focal length of the first lens unit L1 is higher than the upper limit in inequality (1), the amount of movement of the second subunit L12 during focusing is increased. Therefore, the thickness of the first lens unit L1 increases and the lens diameter increases, making it difficult to reduce the size of the zoom lens. When the ratio of the focal length of the subsequent subunit L1R to the focal length of the first lens unit L1 becomes lower than the lower limit in conditional equation (1), it becomes difficult to correct aberrations at the telephoto end.

[0050] The above structure provides a small and lightweight zoom lens with a large aperture diameter and high optical performance throughout the zoom range.

[0051] The range of values ​​for inequality (1) can be used instead of the range of values ​​for inequality (1a).

[0052] 0.30 <f1R / f1<1.00 (1a)

[0053] The range of values ​​for inequality (1) can be used instead of the range of values ​​for inequality (1b).

[0054] 0.40 <f1R / f1<0.95 (1b)

[0055] Next, the structures that can be satisfied by zoom lenses according to each example will be explained.

[0056] The zoom lens according to the various examples may include an aperture stop configured to move along the optical axis during zooming. Because of the movable aperture stop, it becomes easy to position the aperture on the object side at the wide-angle end, making it easy to achieve the effect of moving the incident pupil towards the object side and reducing the lens diameter of the first lens unit L1.

[0057] Multiple zoom lens units may include three or more lens units. Zooming with three or more lens units can easily correct aberrations that increase with increasing aperture diameter and achieve high optical performance throughout the zoom range.

[0058] The subsequent sub-unit L1R may include a third sub-unit L13 with positive refractive power. Because the subsequent sub-unit L1R comprises a single lens unit, the first lens unit L1 can be thin, the increase in the lens diameter of the first lens unit L1 can be suppressed, and the zoom lens can be formed small and lightweight. The third sub-unit L13, which constitutes a lens unit of the subsequent sub-unit L1R, can be fixed during focusing (or not moved for focusing). Thus, aberration fluctuations during focusing are reduced throughout the zoom range.

[0059] Next, we will explain the conditions that can be satisfied by the zoom lenses in each example. One or more of the following inequalities (2) to (6) can be satisfied by the zoom lenses in each example:

[0060] 0.20 <L1 / f1<2.00 (2)

[0061] -4.80 <f12 / f1<-0.20 (3)

[0062] -6.50 <f1 / f2<-1.35 (4)

[0063] -0.60<β12 / β1R<0.00 (5)

[0064] 0.00<(Rn1-Rn2) / (Rn1+Rn2)<5.00 (6)

[0065] Wherein, L1 is the distance on the optical axis from the surface of the first lens unit L1 closest to the object to the surface of the first lens unit L1 closest to the image plane, f12 is the focal length of the second sub-unit L12 when focused at infinity, f2 is the focal length of the second lens unit L2, β12 is the lateral magnification of the second sub-unit L12, β1R is the lateral magnification of the subsequent sub-unit L1R, Rn1 is the radius of curvature of the object-side surface of the first lens (among the lenses with negative refractive power included in the first sub-unit L11 that are closest to the image plane), and Rn2 is the radius of curvature of the image-side surface of the first lens.

[0066] Inequality (2) defines the ratio of the distance along the optical axis from the surface of the first lens unit L1 closest to the object to the surface of the first lens unit L1 closest to the image plane to the focal length of the first lens unit L1. Satisfying inequality (2) allows for a large aperture diameter, small size, light weight, and high optical performance. When the first lens unit L1 becomes thicker and exceeds the upper limit of inequality (2), the lens diameter of the first lens unit L1 increases, and miniaturization becomes difficult. Furthermore, the focal length of the first lens unit L1 decreases, and it becomes difficult to adequately correct aberrations. When the first lens unit L1 becomes thinner and falls below the lower limit of inequality (2), the number of usable lenses decreases, and it becomes difficult to adequately correct aberrations.

[0067] Inequality (3) defines the ratio of the focal length of the second subunit L12 to the focal length of the first lens unit L1. Satisfying inequality (3) allows for a large aperture diameter, small size, light weight, and high optical performance during focusing. When the focal length of the second subunit L12 becomes smaller and exceeds the upper limit in inequality (3), it becomes difficult to correct aberration fluctuations during focusing from an infinity object to a short distance object. When the focal length of the second subunit L12 becomes larger and falls below the lower limit in inequality (3), the distance (interval) required during focusing from an infinity object to a short distance object increases, and the first lens unit L1 becomes thicker. As a result, the first lens unit L1 becomes thicker, the lens diameter increases, making it difficult to reduce size and weight.

[0068] Inequality (4) defines the ratio of the focal length of the first lens unit L1 to the focal length of the second lens unit L2. Satisfying inequality (4) allows for a large aperture diameter, small size, light weight, and high optical performance during focusing. When the focal length of the first lens unit L1 increases beyond the upper limit of inequality (4), the thickness of the first lens unit L1 increases and the lens diameter increases, making it difficult to reduce the size and weight of the zoom lens. When the focal length of the first lens unit L1 becomes smaller and falls below the lower limit of inequality (4), while this is advantageous for miniaturization, it becomes difficult to correct aberrations.

[0069] Inequality (5) defines the ratio of the lateral magnification of the second sub-unit L12 to the lateral magnification of the subsequent sub-unit L1R. Satisfying inequality (5) allows for a large aperture diameter, small size, and light weight. If the lateral magnification of the second sub-unit L12 becomes smaller or the lateral magnification of the subsequent sub-unit L1R becomes larger, exceeding the upper limit in inequality (5), it becomes difficult to correct aberrations. If the lateral magnification of the second sub-unit L12 becomes larger or the lateral magnification of the subsequent sub-unit L1R becomes smaller, falling below the lower limit in inequality (5), the movement of the second sub-unit L12 during focusing becomes larger. Therefore, the first lens unit L1 becomes thicker and the lens diameter increases, making it difficult to miniaturize the zoom lens.

[0070] Inequality (6) defines the ratio of the curvature of the object-side surface of the first lens (the one closest to the image plane among the negative refractive power lenses included in the first subunit L11) to the curvature of the image-side surface of the first lens. When this value is higher than the upper limit in inequality (6), the object-side surface of the first lens becomes concave, and off-axis rays are significantly refracted, especially at the wide-angle end, and it becomes difficult to suppress fluctuations in off-axis aberrations during focusing. When this value is lower than the lower limit in inequality (6), the image-side surface of the first lens becomes convex, and it becomes difficult to suppress fluctuations in off-axis aberrations during focusing.

[0071] The numerical ranges of the following inequalities (2a) to (6a) can be used instead of the numerical ranges of inequalities (2) to (6).

[0072] 0.30 <L1 / f1<1.80 (2a)

[0073] -4.70 <f12 / f1<-0.40 (3a)

[0074] -5.00 <f1 / f2<-1.40 (4a)

[0075] -0.49 < β12 / β1R < -0.02 (5a)

[0076] 0.20<(Rn1-Rn2) / (Rn1+Rn2)<3.00 (6a)

[0077] The numerical ranges of the following inequalities (2b) to (6b) can be used instead of the numerical ranges of inequalities (2) to (6).

[0078] 0.40 <L1 / f1<1.60 (2b)

[0079] -4.60 <f12 / f1<-0.60 (3b)

[0080] -3.50 <f1 / f2<-1.45 (4b)

[0081] -0.40 < β12 / β1R < -0.04 (5b)

[0082] 0.40<(Rn1-Rn2) / (Rn1+Rn2)<1.50 (6b)

[0083] Detailed descriptions of zoom lenses based on various examples will now be provided.

[0084] The zoom lens according to Example 1 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations with zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fourth lens unit L4 and is closest to the object side within the fourth lens unit L4.

[0085] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0086] The zoom lens according to Example 2 includes, in order from the object side to the image side, first lens units to fourth lens units L1 to L4, having positive refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fourth lens unit L4 is the last lens unit. The first lens unit L1 and the fourth lens unit L4 are the focusing lens unit and the imaging lens unit, respectively. The second lens unit L2 and the third lens unit L3 are zoom lens units that move during zooming. During zooming, the third lens unit L3 moves non-linearly along the optical axis in relation to the movement of the second lens unit L2, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fourth lens unit L4 are fixed during zooming (or do not move for zooming). An aperture stop SP is arranged between the second lens unit L2 and the third lens unit L3 and moves independently of the individual lens units during zooming.

[0087] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0088] The zoom lens according to Example 3 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fourth lens unit L4 and is closest to the object within the fourth lens unit L4.

[0089] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to sixth surfaces, the second sub-unit L12 corresponds to the seventh to eleventh surfaces, and the third sub-unit L13 corresponds to the twelfth to sixteenth surfaces.

[0090] The zoom lens according to Example 4 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fifth lens unit L5 and is closest to the object within the fifth lens unit L5.

[0091] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0092] The zoom lens according to Example 5 includes, in order from the object side to the image side, first lens units to sixth lens units L1 to L6, having positive refractive power, negative refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The sixth lens unit L6 is the last lens unit. The first lens unit L1 is a focusing lens unit. The second to sixth lens units L2 to L6 are zoom lens units that move during zooming. During zooming, the fifth lens unit L5 moves non-linearly along the optical axis in association with the movement of the second lens unit L2, the third lens unit L3, and the fourth lens unit L4, and corrects for image plane fluctuations. The first lens unit L1 is fixed during zooming (or does not move for zooming). The aperture stop SP is included in the fifth lens unit L5 and is closest to the object within the fifth lens unit L5.

[0093] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, a third sub-unit L13 with positive refractive power, and a fourth sub-unit L14 with positive refractive power. In this example, the third sub-unit L13 and the fourth sub-unit L14 form a subsequent sub-unit (at least one subsequent sub-unit) L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 and the fourth sub-unit L14 are moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, the third sub-unit L13 corresponds to the eighth to twelfth surfaces, and the fourth sub-unit L14 corresponds to the thirteenth and fourteenth surfaces.

[0094] The zoom lens according to Example 6 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fourth lens unit L4 and is closest to the object within the fourth lens unit L4. The aperture stop SP changes its diameter during zooming.

[0095] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0096] The zoom lens according to Example 7 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fourth lens unit L4 and is closest to the object within the fourth lens unit L4.

[0097] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to sixth surfaces, the second sub-unit L12 corresponds to the seventh to ninth surfaces, and the third sub-unit L13 corresponds to the tenth to sixteenth surfaces.

[0098] The zoom lens according to Example 8 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, positive refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the fourth lens unit L4 and is closest to the object within the fourth lens unit L4.

[0099] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0100] The zoom lens according to Example 9 includes, in order from the object side to the image side, first lens units to fifth lens units L1 to L5, having positive refractive power, negative refractive power, negative refractive power, positive refractive power, and positive refractive power, respectively. The fifth lens unit L5 is the last lens unit. The first lens unit L1 and the fifth lens unit L5 are the focusing lens unit and the imaging lens unit, respectively. The second to fourth lens units L2 to L4 are zoom lens units that move during zooming. During zooming, the fourth lens unit L4 moves non-linearly along the optical axis in association with the movement of the second lens unit L2 and the third lens unit L3, and corrects for image plane fluctuations during zooming. The first lens unit L1 and the fifth lens unit L5 are fixed during zooming (or do not move for zooming). The aperture stop SP is included in the third lens unit L3 and is closest to the object within the third lens unit L3.

[0101] The first lens unit L1 includes, in order from the object side to the image side, a first sub-unit L11 with negative refractive power, a second sub-unit L12 with negative refractive power, and a third sub-unit L13 with positive refractive power. In this example, the third sub-unit L13 is a subsequent sub-unit L1R. The first sub-unit L11 and the third sub-unit L13 are fixed during focusing (or do not move for focusing). The second sub-unit L12 is moved to the object side during focusing from an infinity object to a short distance object. The first sub-unit L11 corresponds to the first to fourth surfaces, the second sub-unit L12 corresponds to the fifth to seventh surfaces, and the third sub-unit L13 corresponds to the eighth to fourteenth surfaces.

[0102] The following will show the numerical examples 1 to 9 corresponding to Examples 1 to 9.

[0103] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial distance (distance along the optical axis) between the m-th and (m+1)-th surfaces, where m is the surface number counting from the light incident side. nd represents the refractive index of each optical element about the d-line, and νd represents the Abbe number of the optical element. The Abbe number νd of a certain material is expressed as follows:

[0104] νd=(Nd-1) / (NF-NC)

[0105] Nd, NF, and NC are the refractive indices of the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer line.

[0106] In each numerical example, all values ​​for d, focal length (mm), F-number, and half angle of view (°) are set with the zoom lens in each example focused on an object at infinity. "Backfocus" is the distance along the optical axis from the last lens surface (the lens surface closest to the image plane) to the paraxial image plane, and is converted to airequivalent length. "Total lens length" is the length obtained by adding the backfocus to the distance along the optical axis from the foremost (the lens surface closest to the object) to the rearmost of the zoom lens. A "lens unit" can be one or more lenses.

[0107] When the optical surface is aspherical, an asterisk (*) is appended to the right of the surface number. The shape of an aspherical surface is expressed as follows:

[0108] x=(h 2 / R) / [1+{1-(1+k)(h / R) 2} 1 / 2 +A4×h 4+A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12 +A14×h 14 +A16×h 16 +A3×h 3 +A5×h 5 +A7×h 7 +A9×h 10 +A11×h 11 +A13×h 13 +A15×h 15

[0109] Where x is the displacement from the vertex of the face along the optical axis, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature, k is the conic constant, and A3 to A16 are the aspheric coefficients in that order. Furthermore, "e±XX" in each aspheric coefficient refers to "×10"... ±XX ".

[0110] [Numerical Example 1]

[0111] Unit: mm

[0112] Surface data

[0113]

[0114]

[0115]

[0116] Aspherical data

[0117] Page 26

[0118] K=0.00000e+000 A4=-1.13870e-006 A6=8.24584e-011A8=-1.78933e-013

[0119] Various data

[0120]

[0121]

[0122] Zoom lens unit data

[0123]

[0124] [Numerical Example 2]

[0125] Unit: mm

[0126] Surface data

[0127]

[0128]

[0129]

[0130] Aspherical data

[0131] Page 13

[0132] K=0.00000e+000 A4=-8.18901e-008 A6=-1.90678e-011 A8=1.42909e-015

[0133] Page 15

[0134] K=0.00000e+000 A4=2.01415e-006 A6=-1.21880e-009 A8=1.66437e-012

[0135] Page 23

[0136] K=0.00000e+000 A4=-1.06285e-006 A6=8.18942e-010 A8=-8.94142e-013

[0137] Various data

[0138]

[0139]

[0140]

[0141] Zoom lens unit data

[0142]

[0143] [Numerical Example 3]

[0144] Unit: mm

[0145] Surface data

[0146]

[0147]

[0148]

[0149] Aspherical data

[0150] Page 1

[0151] K=0.00000e+000 A4=3.99591e-009 A6=5.12355e-011 A8=-1.64561e-014

[0152] Page 10

[0153] K=0.00000e+000 A4=-1.06083e-008 A6=-1.40632e-011 A8=3.32660e-015

[0154] Page 28

[0155] K=0.00000e+000 A4=-1.54169e-006 A6=1.56757e-010 A8=-9.78365e-013

[0156] Various data

[0157]

[0158]

[0159] Zoom lens unit data

[0160]

[0161] [Numerical Example 4]

[0162] Unit: mm

[0163] Surface data

[0164]

[0165]

[0166] Aspherical data

[0167] Page 13

[0168] K=0.00000e+000 A4=2.42678e-009 A6=6.30738e-012 A8=-1.54807e-015

[0169] Page 25

[0170] K=0.00000e+000 A4=-1.02688e-006 A6=4.84075e-011A8=-8.15923e-014

[0171] Various data

[0172]

[0173]

[0174] Zoom lens unit data

[0175]

[0176] [Numerical Example 5]

[0177] Unit: mm

[0178] Surface data

[0179]

[0180]

[0181] Aspherical data

[0182] Page 26

[0183] K=0.00000e+000 A4=-9.99589e-007 A6=-3.30011e-010 A8=2.67589e-013

[0184] Various data

[0185]

[0186]

[0187] Zoom lens unit data

[0188]

[0189] [Numerical Example 6]

[0190] Unit: mm

[0191] Surface data

[0192]

[0193]

[0194] Aspherical data

[0195] Page 8

[0196] K=0.00000e+000 A4=-2.31283e-008 A6=3.95673e-012 A8=-1.09447e-015

[0197] Page 26

[0198] K=0.00000e+000 A4=1.21365e-006 A6=-2.16657e-011 A8=-2.45189e-013

[0199] Various data

[0200]

[0201]

[0202]

[0203] Zoom lens unit data

[0204]

[0205] [Numerical Example 7]

[0206] Unit: mm

[0207] Surface data

[0208]

[0209]

[0210]

[0211] Aspherical data

[0212] Page 10

[0213] K=0.00000e+000 A4=-2.53004e-007 A6=5.98970e-011 A8=-1.25485e-014

[0214] Page 17

[0215] K=0.00000e+000 A4=2.24213e-006 A6=-3.64547e-010 A8=1.83794e-012

[0216] Page 30

[0217] K=0.00000e+000 A4=-1.61666e-006 A6=3.08898e-011 A8=-5.53302e-013

[0218] Various data

[0219]

[0220]

[0221] Zoom lens unit data

[0222]

[0223] [Numerical Example 8]

[0224] Unit: mm

[0225] Surface data

[0226]

[0227]

[0228] Various data

[0229]

[0230]

[0231]

[0232] Zoom lens unit data

[0233]

[0234] [Numerical Example 9]

[0235] Unit: mm

[0236] Surface data

[0237]

[0238]

[0239]

[0240] Aspherical data

[0241] Page 8

[0242] K=0.00000e+000 A4=1.63015e-008 A6=1.82004e-011 A8=-6.10670e-015

[0243] Page 26

[0244] K=0.00000e+000 A4=-1.15351e-006 A6=1.34077e-010 A8=-7.01868e-016

[0245] Various data

[0246]

[0247]

[0248]

[0249] Zoom lens unit data

[0250]

[0251] Table 1 below summarizes the various values ​​in the numerical examples.

[0252] Table 1

[0253]

[0254]

[0255] camera equipment

[0256] Figure 20 This is a schematic diagram of a camera device (television camera system) using a zoom lens for a camera optical system according to various examples.

[0257] exist Figure 20In the figures, reference numeral 101 denotes a zoom lens according to any one of Examples 1 to 9, and reference numeral 124 denotes a camera. The zoom lens 101 is attached to and detached from the camera 124. Reference numeral 125 denotes an imaging device formed by attaching the zoom lens 101 to the camera 124. The zoom lens 101 includes a first lens unit F, a zoom lens unit LZ, and a rear unit R for imaging, including lens units R1 and R2. The first lens unit F includes a focusing lens unit. The zoom lens unit LZ includes a second lens unit and a third lens unit that move along the optical axis during zooming, and a fourth lens unit that moves along the optical axis to correct for image plane fluctuations during zooming. SP denotes an aperture stop (aperture). Reference numerals 114 and 115 denote drive mechanisms such as a helix and a cam that drive the first lens unit F and the zoom lens unit LZ in the optical axis direction, respectively. Reference numerals 116 to 118 denote motors (drive units) configured to drive drive mechanisms 114 and 115 and the aperture SP, respectively. Reference numerals 119 and 120 denote detectors such as encoders, potentiometers, or photoelectric sensors for detecting the positions of the first lens unit F and the zoom lens unit LZ on the optical axis. Reference numeral 121 denotes detectors such as encoders, potentiometers, or photon sensors for detecting the aperture diameter of the aperture SP. In the camera 124, reference numeral 109 denotes a glass block corresponding to the optical filter and color decomposition optical system in the camera 124, and reference numeral 110 denotes solid-state image sensors (image-capturing elements or photoelectric conversion elements) such as CCD sensors and CMOS sensors for capturing images formed by the zoom lens 101. Reference numerals 111 and 122 denote CPUs controlling various drives of the camera 124 and the zoom lens 101, respectively.

[0258] As described above, applying a zoom lens, according to any one example, to imaging devices such as television cameras, cinema cameras, and digital still cameras can provide imaging devices with high optical performance.

[0259] The examples above can provide zoom lenses that offer advantages such as large aperture diameter, small size, light weight, and high optical performance throughout the entire zoom range.

[0260] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be interpreted in the broadest possible sense to include all such modifications and equivalent structures and functions.

Claims

1. A zoom lens comprising, in order from the object side to the image side: The first lens unit has positive refractive power; Multiple zoom lens units are configured to move along the optical axis during zooming, and include lens units with negative refractive power; as well as Finally, the lens unit has positive refractive power. The distance between each pair of adjacent lens units changes during zooming. The plurality of zoom lens units include three or more lens units. The plurality of zoom lens units include an aperture stop configured to move along the optical axis during zooming. The first lens unit is characterized in that it comprises, in order from the object side to the image side: a first sub-unit having negative refractive power, a second sub-unit having negative refractive power, and at least one subsequent sub-unit, wherein the distance between each pair of adjacent sub-units varies with focusing. The second subunit is configured to move along the optical axis for focusing, and Among them, the following inequalities are satisfied: 0.20 < f1R / f1 < 1.10, -0.60 < β12 / β1R < 0.00， Wherein, f1R is the focal length of the at least one subsequent sub-unit in the state of focusing at infinity, f1 is the focal length of the first lens unit in the state of focusing at infinity, β12 is the lateral magnification of the second sub-unit in the state of focusing at infinity, and β1R is the lateral magnification of the at least one subsequent sub-unit in the state of focusing at infinity.

2. The zoom lens according to claim 1, characterized in that, The first lens unit is configured not to move during zooming.

3. The zoom lens according to claim 1, characterized in that, The following inequalities must be satisfied: 0.20 < L1 / f1 < 2.00, Wherein, L1 is the distance on the optical axis from the surface of the first lens unit closest to the object side to the surface of the first lens unit closest to the image side.

4. The zoom lens according to claim 1, characterized in that, The following inequalities must be satisfied: -4.80 < f12 / f1 < -0.20, Wherein, f12 is the focal length of the second sub-unit in the state of focusing at infinity.

5. The zoom lens according to claim 1, characterized in that, The plurality of zoom lens units includes a second lens unit that is closest to the object side among the plurality of zoom lens units, and satisfies the following inequality: -6.50 < f1 / f2 < -1.35, Where f2 is the focal length of the second lens unit.

6. The zoom lens according to claim 1, characterized in that, The following inequalities must be satisfied: 0 < (Rn1-Rn2) / (Rn1+Rn2) < 5.00, Wherein, Rn1 is the radius of curvature of the object-side surface of the first lens, and Rn2 is the radius of curvature of the image-side surface of the first lens, wherein the first lens is arranged to be closest to the image side among at least one lens with negative refractive power included in the first subunit.

7. The zoom lens according to claim 1, characterized in that, The plurality of zoom lens units include a second lens unit with negative refractive power and a third lens unit with positive refractive power in order from the object side to the image side.

8. The zoom lens according to claim 1, characterized in that, The plurality of zoom lens units include, in order from the object side to the image side, a second lens unit with negative refractive power, a third lens unit with negative refractive power, and a fourth lens unit with positive refractive power.

9. The zoom lens according to claim 1, characterized in that, The plurality of zoom lens units include, in order from the object side to the image side, a second lens unit with negative refractive power, a third lens unit with positive refractive power, and a fourth lens unit with positive refractive power.

10. The zoom lens according to claim 1, characterized in that, The plurality of zoom lens units include, in order from the object side to the image side, a second lens unit with negative refractive power, a third lens unit with negative refractive power, a fourth lens unit with negative refractive power, a fifth lens unit with positive refractive power, and a sixth lens unit with positive refractive power.

11. The zoom lens according to claim 1, characterized in that, The at least one subsequent subunit includes a third subunit having positive refractive power.

12. The zoom lens according to claim 11, characterized in that, The third subunit is configured not to move for focusing.

13. The zoom lens according to claim 1, characterized in that, The at least one subsequent subunit includes a third subunit and a fourth subunit having positive refractive power in order from the object side to the image side.

14. The zoom lens according to claim 13, characterized in that, The third subunit is configured not to move in response to focusing, and the fourth subunit is configured to move in response to focusing.

15. A camera device, comprising: The zoom lens according to any one of claims 1 to 14; as well as An image sensor is configured to capture images formed by the zoom lens.

Images