Zoom lens and imaging device

Abstract

It allows for the insertion of an extender group, providing a compact and high-performance zoom lens. [Solution] A zoom lens having a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes when zooming, and further having an extender group that changes the focal length of the zoom lens by being inserted into or removed from the optical path, wherein the focal length f1 of the first lens group, the focal length ft at the telephoto end of the zoom lens, the distance D on the optical axis from the final lens group closest to the image to the lens group adjacent to the final lens group when infinity focus is achieved at the telephoto end, the distance TL on the optical axis from the lens surface closest to the object to the image plane when infinity focus is achieved at the telephoto end, the focal length f3 of the third lens group, and the focal length f4 of the fourth lens satisfy a predetermined conditional equation.

Description

[Technical Field]

[0001] This invention relates to a zoom lens and an imaging device. [Background technology]

[0002] Patent documents 1 and 2 disclose an optical system (telephoto lens) in which a magnification conversion optical group (extender group) for extending the focal length at the telephoto end can be inserted and removed. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 5409841 [Patent Document 2] Japanese Patent Publication No. 2019-120771 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the optical systems disclosed in Patent Documents 1 and 2, an extender is provided on the image side of the aperture for the purpose of miniaturization. In this case, since it is necessary to ensure a wider spacing between the lens groups on the image side of the aperture, the focusing lens group must be placed on the object side of the aperture. When the focusing lens group is placed on the object side of the aperture, the diameter of the focusing lens group becomes larger and heavier because it is determined by the Fno optical beam diameter at the telephoto end, making it impossible to achieve high-speed drive.

[0005] Therefore, the present invention aims to provide a compact, high-performance zoom lens and imaging device that can accommodate an extender group. [Means for solving the problem]

[0006] A zoom lens as one aspect of the present invention comprises a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, an extender group, and a fifth lens group with positive refractive power, arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, and the focal length of the zoom lens changes when the extender group is inserted into or removed from the optical path, and the lens group located closest to the object in the first lens group The lens has a positive refractive power, the first lens group has a cemented lens, and the focal length f1 of the first lens group, the focal length ft at the telephoto end of the zoom lens, the focal length f2 of the second lens group, the distance D on the optical axis from the fifth lens group to the fourth lens group when in focus at the telephoto end, the distance TL on the optical axis from the lens surface closest to the object to the image plane when in focus at the telephoto end, the focal length f3 of the third lens group, and the focal length f4 of the fourth lens group satisfy a predetermined conditional equation.

[0007] Other objects and features of the present invention are described in the following examples. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a compact, high-performance zoom lens and imaging device that can accommodate an extender group. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view at the wide-angle end in Example 1. [Figure 2] These are aberration diagrams for Example 1 at (a) the wide-angle end, (b) the intermediate zoom position, and (c) the telephoto end. [Figure 3] This is a cross-sectional view at the wide-angle end in Example 2. [Figure 4] These are aberration diagrams for Example 2 at (a) the wide-angle end, (b) the intermediate zoom position, and (c) the telephoto end. [Figure 5] This is a cross-sectional view at the wide-angle end in Example 3. [Figure 6]It is an aberration diagram at (a) wide-angle end, (b) intermediate zoom position, and (c) telephoto end in Example 3. [Figure 7] It is a cross-sectional view at the wide-angle end in Example 4. [Figure 8] It is an aberration diagram at (a) wide-angle end, (b) intermediate zoom position, and (c) telephoto end in Example 4. [Figure 9] It is a cross-sectional view at the wide-angle end in Example 5. [Figure 10] It is an aberration diagram at (a) wide-angle end, (b) intermediate zoom position, and (c) telephoto end in Example 5. [Figure 11] It is a cross-sectional view at the wide-angle end in Example 6. [Figure 12] It is an aberration diagram at (a) wide-angle end, (b) intermediate zoom position, and (c) telephoto end in Example 6. [Figure 13] It is a cross-sectional view at the wide-angle end in Examples 1-2. [Figure 14] It is a cross-sectional view at the wide-angle end in Examples 3-2. [Figure 15] It is a cross-sectional view at the wide-angle end in Examples 4-2. [Figure 16] It is a cross-sectional view at the wide-angle end in Examples 5-2. [Figure 17] It is a cross-sectional view at the wide-angle end in Examples 6-2. [Figure 18] It is a schematic diagram of an imaging device equipped with an optical system in each example.

Modes for Carrying Out the Invention

[0010] Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

[0011] FIGS. 1, 3, 5, 7, 9, and 11 are cross-sectional views at the wide-angle end of the optical systems (zoom lenses) 1a to 1f of Examples 1 to 6, respectively, when focused at infinity. The optical system of each example is an imaging optical system used in an imaging device such as a digital video camera, a digital still camera, a broadcast camera, a silver halide film camera, a surveillance camera, etc.

[0012] In each cross-sectional view, the left side is the object side (magnifying conjugate plane side), and the right side is the image side (reducing conjugate plane side). The optical system of each embodiment is composed of the first lens group B1, the second lens group B2, the third lens group B3, the fourth lens group B4, and the fifth lens group B5, in order from the object side to the image side. In each embodiment, a lens group is a collection of lenses that move together or remain stationary during zooming. In the optical system of each embodiment, the distance between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end. The wide-angle end and the telephoto end are the zoom states when the lens group that moves during zooming is located at both ends of the range in which it can move mechanically in the direction along the optical axis OA (in the optical axis direction). Note that a lens group may consist of one lens or multiple lenses. Also, a lens group may include an aperture (diaphragm) SP.

[0013] The aperture SP determines (limits) the light beam at the widest aperture F-number (Fno). The IP is the image plane (reduced conjugate plane), and when the optical system of each embodiment is used as an imaging optical system for a digital video camera or digital still camera, the imaging surface of an image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor is placed on the image plane IP. When the optical system of each embodiment is used as an imaging optical system for a silver halide film camera, the photosensitive surface of the film is placed on the image plane IP.

[0014] In the optical system of each embodiment, when zooming from the wide-angle end to the telephoto end, each lens group is moved as shown by the solid arrows in each cross-sectional view. Also, when focusing from an object at infinity to the closest object, the fourth lens group (focusing lens group) B4 is moved as shown by the arrow "focus".

[0015] Figures 2, 4, 6, 8, 10, and 12 are longitudinal aberration diagrams of the optical systems 1a to 1f of Examples 1 to 6, respectively. In each aberration diagram, (A) shows the longitudinal aberration diagram at the wide-angle end and infinity focus, (B) shows the longitudinal aberration diagram at the intermediate zoom position and infinity focus, and (C) shows the longitudinal aberration diagram at the telephoto end and infinity focus.

[0016] In the spherical aberration diagram, Fno is the F-number, and the diagram shows the amount of spherical aberration for the d-line (wavelength 587.6 nm), g-line (wavelength 435.8 nm), C-line (wavelength 656.3 nm), and F-line (wavelength 486.1 nm). In the astigmatism diagram, S is the amount of astigmatism at the sagittal image plane, and M is the amount of astigmatism at the meridional image plane. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration for the g-line, C-line, and F-line is shown. ω is the half-angle of view (degrees).

[0017] Next, the characteristic configurations of the optical system (zoom lens) in each embodiment will be described. The optical system in each embodiment has a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, a fourth lens group B4 with negative refractive power, and a fifth lens group B5 with positive refractive power, arranged in order from the object side to the image side. In addition, the spacing between adjacent lens groups changes when zooming. Furthermore, the optical system in each embodiment has a magnification conversion optical group (extender group EXT) that changes the focal length of the zoom lens by being inserted into or removed from the optical path.

[0018] In each embodiment, the first lens group B1 satisfies the following condition (1).

[0019] 0.60 <f1 / ft<1.50 ···(1) In condition (1), f1 is the focal length of the first lens group B1, and ft is the focal length at the telephoto end of the optical system. If the upper limit of condition (1) is exceeded, the power (refractive force) of the first lens group B1 becomes weak. As a result, it becomes impossible to miniaturize the optical system at the telephoto end, or to lengthen the focal length at the telephoto end. On the other hand, if the lower limit of condition (1) is exceeded, the power of the first lens group B1 becomes too strong. While this is effective for lengthening the focal length at the telephoto end, the excessive power leads to an increase in spherical aberration at the telephoto end, and an increase in distortion and chromatic aberration across the entire magnification range.

[0020] Furthermore, in each embodiment, the first lens group B1 and the second lens group B2 satisfy the following condition (2).

[0021] -3.90 <f1 / f2<-0.10 ···(2) In condition (2), f2 is the focal length of the second lens group B2. If the value exceeds the upper limit of condition (2), the power of the second lens group B2 becomes too weak, increasing the amount of movement required to achieve the predetermined magnification and lengthening the optical system. On the other hand, if the value falls below the lower limit of condition (2), the power of the second lens group B2 becomes too strong, allowing for a shorter amount of movement to achieve the predetermined magnification, but failing to suppress chromatic aberration at the wide-angle end, and failing to suppress spherical and axial chromatic aberration at the telephoto end.

[0022] Furthermore, the optical systems of each embodiment satisfy the following conditions (3) and (4).

[0023] 0.10 <D / TL<0.30 ···(3) -5.00 <f3 / f4<-1.00 ···(4) In condition (3), D is the distance along the optical axis from the final lens group closest to the image (5th lens group B5) to the lens group adjacent to the final lens group (4th lens group B4) when the telephoto end is in focus at infinity. TL is the distance along the optical axis from the lens surface closest to the object to the image plane IP when the telephoto end is in focus at infinity. In condition (4), f3 is the focal length of the 3rd lens group B3, and f4 is the focal length of the 4th lens group B4.

[0024] If the upper limit of condition (3) is exceeded, the air gap containing the extender group will be made too wide. In this case, the distance from the first lens group B1 to the fourth lens group B4, which have the main imaging function, becomes too short, requiring stronger power in each lens group, which makes it difficult to suppress aberrations, or increases the number of lenses in each lens group in order to suppress aberrations well, thus increasing costs.

[0025] On the other hand, if the value falls below the lower limit of condition (3), the air gap surrounding the extender group becomes too narrow, resulting in the required size of the extender group becoming too small, making it impossible to suppress the aberrations of the extender group. Alternatively, it becomes necessary to use aspherical lenses to adequately suppress the aberrations of the extender group, which increases costs.

[0026] If the upper limit of condition (4) is exceeded, the power of the third lens group B3 becomes too strong compared to the fourth lens group B4. A strong power in the third lens group B3 has the advantage of compressing the light beam incident on the subsequent fourth lens group B4, thus reducing the weight of the fourth lens group B4. However, if the upper limit of condition (4) is exceeded, the excessive power of the third lens group B3 leads to excessive spherical aberration and axial chromatic aberration at the wide-angle end. Furthermore, attempting to suppress these aberrations with the third lens group B3 requires a larger number of lenses, increasing the weight of the optical system and raising costs.

[0027] On the other hand, if the value falls below the lower limit of condition (4), the power of the third lens group B3 becomes too weak compared to the fourth lens group B4. If the power of the third lens group B3 becomes too weak, it is not possible to compress the light beam incident on the subsequent fourth lens group B4, so the diameter of the fourth lens group B4 as the focusing lens group increases. As the diameter of the fourth lens group B4 increases, its weight increases, making high-speed drive impossible. In addition, the optical system becomes longer because it becomes more difficult to focus the light beam. If an attempt is made to increase the power of the fifth lens group B5 as the final lens group to focus the light in order to prevent this, the ray angle of the off-axis rays also changes sharply, which increases chromatic aberration.

[0028] In the optical system of each embodiment, the final lens group (fifth lens group B5) is fixed (it does not move during zooming). This is because, if a built-in extender insertion / removal mechanism is provided in the space directly in front of the final lens group, it is difficult to construct the group with the same cam across the built-in extender.

[0029] Preferably, the optical system of each embodiment satisfies the following condition (5).

[0030] -0.50 <f4 / ft<-0.05 ···(5) If the value falls below the lower limit of condition (5), the power of the fourth lens group B4 becomes too weak. When the power of the fourth lens group B4, which is the focusing lens group, becomes weak, it becomes necessary to ensure a larger travel distance when focusing, which either makes the optical system larger or narrows the focusing range. On the other hand, if the value exceeds the upper limit of condition (5), the power of the fourth lens group B4 becomes too strong. When the power of the fourth lens group B4 becomes strong, there is the advantage that the group travel distance when focusing can be shortened, but it becomes necessary to increase the number of elements in the fourth lens group B4 in order to suppress aberration fluctuations when focusing, which increases the weight of the fourth lens group B4.

[0031] Preferably, the optical system of each embodiment satisfies the following condition (6).

[0032] 0.10 <f5 / ft<2.00 ···(6) In condition (6), f5 is the focal length of the fifth lens group B5. If the value exceeds the upper limit of condition (6), the power of the fifth lens group B5 becomes too weak. The fifth lens group B5 plays the role of forming an image on the sensor surface (image plane IP) from the light beam emitted from the fourth lens group B4, while matching the image plane size, and also has the function of canceling out distortion aberration that could not be suppressed by the first lens group B1. If the power of the fifth lens group B5 becomes too weak, it will no longer be able to cancel out distortion aberration. On the other hand, if the value falls below the lower limit of condition (6), the power of the fifth lens group B5 becomes too strong. If the power of the fifth lens group B5 becomes too strong, the amount of distortion generated will increase, and even if the distortion aberration generated in the first lens group B1 is canceled out, distortion aberration will still occur within the fifth lens group B5.

[0033] More preferably, the numerical ranges of conditional expressions (1) to (6) are set to satisfy the following conditional expressions (1a) to (6a).

[0034] 0.61 <f1 / ft<1.20 ···(1a) -3.80 <f1 / f2<-1.00 ···(2a) 0.12 <D / TL<0.25 ···(3a) -3.50 <f3 / f4<-1.03 ···(4a) -0.30 <f4 / ft<-0.06 ···(5a) 0.15 <f5 / ft<1.00 ···(6a) More preferably, the numerical ranges of conditional expressions (1) to (6) are set to satisfy the following conditional expressions (1b) to (6b).

[0035] 0.62 <f1 / ft<1.00 ···(1b) -3.70 <f1 / f2<-2.00 ···(2b) 0.15 <D / TL<0.20 ···(3b) -2.00 <f3 / f4<-1.06 ···(4b) -0.20 <f4 / ft<-0.07 ···(5b) 0.20 <f5 / ft<0.80 ···(6b) Next, the optical systems of each embodiment will be described. [Examples]

[0036] First, with reference to Figure 1, the optical system 1a in Embodiment 1 will be described. The optical system 1a in this embodiment is a telephoto zoom lens. As shown in Figure 1, the optical system 1a consists of, in order from the object side to the image side, a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, a fourth lens group B4 with negative refractive power, and a fifth lens group B5 with positive refractive power. A space is provided between the fourth lens group B4 and the fifth lens group B5 through which a magnification conversion optical group (extender group) can be inserted and removed. When zooming, the second lens group B2 and the fourth lens group B4 move. The second lens group B2 mainly has a magnification function, and the fourth lens group B4 has a function to correct the focus position that moves during magnification.

[0037] The first lens group B1 contributes to the compression of the entire optical system at the telephoto end. The first lens group B1 is fixed (immovable) during zooming and is configured to enhance dust and splash resistance, increasing robustness in adverse weather conditions. The first lens group B1 consists of a first lens with positive refractive power, a second lens with positive refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power. The third and fourth lenses are cemented lenses. The first and second lenses have a strong light-gathering effect, and the third lens is made smaller in diameter by increasing the air gap between the second and third lenses. If the number of light-gathering lenses for the first and second lenses were reduced to one, spherical aberration at the telephoto end would increase. Furthermore, the cemented lens formed by the third and fourth lenses has a negative combined focal length, which cancels out spherical aberration generated by the first and second lenses at the telephoto end, and also cancels out distortion generated by the first and second lenses throughout the entire zoom range.

[0038] The second lens group B2 moves from the object side (in the direction of magnification conjugate) to the image side (in the direction of reduction conjugate) from the wide-angle end to the telephoto end, so that the main imaging performance is handled by the third lens group B3 at the wide-angle end and by the first lens group B1 at the telephoto end. The lens diameter of the second lens group B2 is determined by the off-axis marginal rays at the wide-angle end or the on-axis marginal rays at the telephoto end. At the wide-angle end, the off-axis marginal rays are sufficiently focused by the first lens group B1, so this does not cause an increase in the diameter of the second lens group B2. At the telephoto end, the on-axis marginal rays are sufficiently focused as the second lens group B2 moves in the direction of the reduction conjugate plane, so this does not cause an increase in the diameter of the second lens group B2.

[0039] However, if the second lens group B2 has positive refractive power, it moves from the reducing conjugate plane side to the expanding conjugate plane side when zooming from the wide-angle end to the telephoto end. In this case, the lens diameter of the second lens group B2 becomes larger and heavier because it is determined by the axial marginal ray height at the telephoto end. In addition, one convex lens with positive refractive power is placed as the fourth lens in the second lens group B2. This makes it easier to align the image plane with the second lens group B2 which has negative refractive power. Furthermore, three lenses with negative refractive power are placed in the second lens group B2. This makes it possible to suppress various aberrations by gently bending the off-axis rays at the wide-angle end. It is preferable that the second lens group B2 has at least four lenses.

[0040] The third lens group B3 contributes to the compression of the entire optical system at the wide-angle end. Low-dispersion convex lenses are used to suppress axial chromatic aberration. In this embodiment, the third lens group B3 does not move during zooming, but it may be made to move during zooming to suppress aberration fluctuations.

[0041] The fourth lens group is a variable magnification lens group that moves during zooming, and is also a focusing lens group that moves from the magnification conjugate direction to the reduction conjugate direction from infinity to the near end during focusing, forming an image of the light beam on the sensor surface. In this embodiment, a cemented lens is used in the focusing lens group, making it easier to suppress chromatic aberration even when the power of the lens group is increased.

[0042] The fifth lens group B5 is a field lens that forms an image on the image sensor surface of the light emitted from the fourth lens group B4. In this embodiment, by positioning the negative lens on the side of the conjugate plane closest to the reduction, it is possible to satisfy the incident angle condition to the image sensor. Furthermore, by creating an air gap between the negative lens and the positive lens positioned directly in front of it within the fifth lens group B5, the height of the off-axis light rays incident on the positive lens is increased, canceling the distortion aberration generated by the negative lens. In this case, the positive lens is a cemented lens to prevent the separation of light rays by color between the air gaps. That is, the final lens group (fifth lens group B5) consists of a cemented lens formed by joining a positive lens and a negative lens, and a negative lens positioned on the image side of the cemented lens. The fifth lens group B5 also plays a role in canceling out distortion aberrations that cannot be suppressed by the first lens group B1.

[0043] Figure 13 is a cross-sectional view of the optical system 1a in Figure 1 with the extender group EXT inserted, at the wide-angle end when infinity focus is achieved. By inserting the extender group EXT between the fourth lens group B4 and the fifth lens group B5 of the optical system 1a in Figure 1, the focal length is increased by approximately 1.4 times, enabling the realization of a more telephoto optical system. [Examples]

[0044] Next, with reference to Figure 3, the optical system 1b in Example 2 will be described. The optical system 1b in this example differs from the optical system 1a in Example 1 in that the fifth lens group B5 has an aspherical lens. That is, the optical system 1b achieves good image plane correction by placing an aspherical lens in the fifth lens group B5, where off-axis rays are separated. In this example, the aspherical lens is formed by bonding a resin material to glass, but the glass may have an aspherical shape. Also, although the bonding target is a cemented lens, it may be bonded to a single lens. [Examples]

[0045] Next, with reference to Figure 5, the optical system 1c in Example 3 will be described. Compared to the optical system 1b in Example 2, the optical system 1c in this example has one less lens constituting the fourth lens group B4, enabling faster drive speeds.

[0046] Figure 14 is a cross-sectional view of the optical system 1c in Figure 5 with the extender group EXT inserted, at the wide-angle end when infinity focus is achieved. By inserting the extender group EXT between the fourth lens group B4 and the fifth lens group B5 of the optical system 1c, the focal length is increased by approximately 1.4 times, enabling the realization of a more telephoto optical system. [Examples]

[0047] Next, with reference to Figure 7, the optical system 1d in Example 4 will be described. Compared to the optical system 1a in Example 1, the optical system 1d in this example extends the telephoto end toward the longer focal length. This further expands the expressive range.

[0048] Figure 15 is a cross-sectional view of the optical system 1d in Figure 7 with the extender group EXT inserted, at the wide-angle end when infinity focus is achieved. By inserting the extender group EXT between the fourth lens group B4 and the fifth lens group B5 of the optical system 1d, the focal length is increased by approximately 1.4 times, enabling the realization of a more telephoto optical system. [Examples]

[0049] Next, with reference to Figure 9, the optical system 1e in Example 5 will be described. The optical system 1e in this example differs from the optical system 1a in Example 1 in that the third lens group B3 moves during zooming. The movement of the third lens group B3 during zooming enables better aberration correction.

[0050] Figure 16 is a cross-sectional view of the optical system 1e in Figure 9 with the extender group EXT inserted, at the wide-angle end when infinity focus is achieved. By inserting the extender group EXT between the fourth lens group B4 and the fifth lens group B5 of the optical system 1e, the focal length is increased by approximately 1.4 times, enabling the realization of a more telephoto optical system. [Examples]

[0051] Next, with reference to Figure 11, the optical system 1f in Embodiment 6 will be described. The optical system 1f in this embodiment differs from the optical system 1a in Embodiment 1 in that the first lens group B1 moves during zooming. The movement of the first lens group B1 during zooming enables better aberration correction at the telephoto end.

[0052] Figure 17 is a cross-sectional view of the optical system 1f in Figure 11 with the extender group EXT inserted, at the wide-angle end when infinity focus is achieved. By inserting the extender group EXT between the fourth lens group B4 and the fifth lens group B5 of the optical system 1f, the focal length is increased by approximately 1.4 times, enabling the realization of a more telephoto optical system.

[0053] Below are the numerical values ​​for Examples 1-6 and Examples 1-2, 3-2 to 6-2, which correspond to the state in which a magnification conversion optical group (extender group) is built into (inserted) in Examples 1, 3 to 6.

[0054] In the surface data for each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axial spacing (distance along the optical axis) between the m-th surface and the (m+1)-th surface. Here, m is the surface number counted from the light incident side. Also, nd represents the refractive index of each optical element with respect to the d-line, and νd represents the Abbe number of the optical element with respect to the d-line. The Abbe number νd is given by Nd, NF, and NC, respectively, when the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) are Nd, NF, and NC. νd = (Nd-1) / (NF-NC) It is represented as follows.

[0055] In each numerical example, d, focal length (mm), F-number, and half angle of view (degrees) are all values when the optical system of each example is focused on an infinitely distant object (at infinity focus). "Back focus" is the distance on the optical axis from the final lens surface (the lens surface closest to the image side) to the paraxial image plane, expressed in terms of the air equivalent length. "Overall lens length" is the length obtained by adding the back focus to the distance on the optical axis from the frontmost surface (the lens surface closest to the object side) to the final surface of the optical system. "Lens group" shall include cases not only composed of a plurality of lenses but also cases composed of a single lens.

[0056] Also, when the optical surface is an aspherical surface, a "*" sign is attached to the right side of the surface number. The aspherical shape is represented by the following formula when x is the displacement amount from the vertex of the surface in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial curvature radius, k is the conic constant, and A4, A6, A8, A10, A12, A14 are the aspherical coefficients of each order.

[0057] 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 Note that "e±XX" in each aspherical coefficient means "×10± XX ".

[0058] (Numerical Example 1) Surface number r d nd νd 1 273.176 7.081 1.487 70.2 2 -1361.262 0.300 3 113.868 11.427 1.434 95.1 4 1751.273 28.392 5 104.514 9.931 1.497 81.5​ 6 -530.570 2.400 1.735 49.8 7 87.663 (variable) 8 85.600 1.800 1.750 35.3 9 34.633 4.083 1.816 46.6 10 43.494 7.461 11 -198.501 1.700 1.528 76.5 12 110.708 0.473 13 63.583 5.393 1.789 28.4 14 602.245 2.877 15 -107.425 1.500 1.497 81.5 16 331.917 (variable) 17 153.599 3.301 1.497 81.5 18 21625.358 0.136 19 57.826 5.529 1.497 81.5 20 398.525 19.982 21 (aperture) ∞ 0.500 22 76.071 2.773 1.497 81.5 23 149.129 7.313 24 -306.956 2.000 1.695 42.2 25 48.393 2.415 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 40.630 4.639 1.497 81.5 32 419.832 (variable) 33 373.891 3.439 1.893 20.4 34 -145.171 1.300 1.852 40.8 35 55.255 2.000 36 993.429 2.000 1.852 40.8 37 63.079 (Variable) 38 76.040 13.902 1.603 38 39 -46.009 1.980 1.808 22.8 40 -72.949 25.690 41 -54.037 1.981 1.729 54.7 42 -229.615 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d7 5.082 36.908 66.439 d16 62.324 30.499 0.967 d32 3.399 3.021 0.413 d37 58.493 58.870 61.479 d42 39.994 39.994 39.994 Wide-angle end, Mid-range, Telephoto end Focal length 206.1 285.0 385.5 F-number 4.1 4.1 4.1 Half-angle 5.99 4.34 3.21 Image height 21.635 21.635 21.635 Lens length 367.62 367.62 367.62 BF 39.994 39.994 39.994 (Numerical Example 2) Face number rd nd νd 1 172.811 9.690 1.487 70.2 2 -4247.264 0.300 3 103.511 11.950 1.434 95.1 4 731.898 18.548 5 90.460 10.390 1.497 81.5 6 -1781.164 2.400 1.773 49.6 7 74.154 (variable) 8 94.630 1.800 1.852 40.8 9 57.576 15.361 10 -328.669 1.700 1.528 76.5 11 95.106 0.991 12 76.714 4.156 1.789 28.4 13 268.446 3.769 14 -110.310 1.500 1.497 81.5 15 -2527.313 (variable) 16 141.332 3.918 1.497 81.5 17 -887.059 0.500 18 61.469 5.534 1.497 81.5 19 491.553 29.245 20 (aperture) ∞ 1.513 21 -301.746 2.000 1.654 39.7 22 53.300 2.202 23 92.105 1.800 1.800 29.8 24 64.222 6.992 1.497 81.5 25 -136.344 0.150 26 96.638 2.687 1.816 46.6 27 330.341 1.000 28 42.050 4.363 1.497 81.5 29 213.941 (variable) 30 733.553 1.727 1.893 20.4 31 -190.560 1.300 1.852 40.8 32 47.179 2.000 33 288.374 1.500 1.816 46.6 34 116.899 (variable) 35* 124.390 0.100 1.516 52.2 36 106.287 10.627 1.800 29.8 37 -45.171 1.500 1.808 22.8 38 -158.049 26.842 39 -36.745 1.500 1.729 54.7 40 -61.263 (variable) Image plane ∞ K c4 c6 d35 0 1.220E-06 3.722E-10 (c8 and later 0) Wide-angle end, Mid-range, Telephoto end d7 2.608 40.865 61.367 d15 59.708 21.451 0.949 d29 5.525 3.956 0.900 d34 58.670 60.239 63.295 d40 39.983 39.983 39.983 Wide-angle end, Mid-range, Telephoto end Focal length 206.4 309.0 383.7 F-number 4.1 4.1 4.1 Half-angle 5.98 4.01 3.23 Image height 21.635 21.635 21.635 Lens length 358.05 358.05 358.05 BF 39.983 39.983 39.983 (Numerical Example 3) Face number rd nd νd 1 217.020 7.911 1.487 70.2 2 -2114.635 0.300 3 108.060 10.941 1.434 95.1 4 799.040 24.642 5 90.882 10.000 1.497 81.5 6 -6626.810 2.400 1.773 49.6 7 77.778 (variable) 8 119.161 1.800 2.001 29.1 9 60.733 6.079 10 -255.201 1.700 1.497 81.5 11 111.954 2.949 12 83.304 4.599 1.855 24.8 13 562.828 3.746 14 -99.723 1.500 1.497 81.5 15 -508.786 (variable) 16 84.172 5.253 1.497 81.5 17 3474.868 0.500 18 80.008 3.901 1.497 81.5 19 250.578 29.600 20 (aperture) ∞ 4.369 21 -271.566 2.000 1.673 38.1 22 59.960 4.617 23 92.105 1.800 1.917 31.6 24 64.222 6.992 1.497 81.5 25 -136.344 0.150 26 96.638 2.687 1.773 49.6 27 330.341 0.999 28 52.525 3.596 1.595 67.7 29 149.095 (variable) 30 481.601 2.203 1.847 23.8 31 -148.197 1.300 1.852 40.8 32 52.346 (Variable) 33* 164.208 0.100 1.516 52.2 34 132.826 9.566 1.728 28.5 35 -45.927 1.500 1.893 20.4 36 -96.765 29.578 37 -37.293 1.500 1.603 65.4 38 -90.046 (variable) Image plane ∞ K c4 c6 d33 0 1.359E-06 3.603E-10 (c8 and later 0) Wide-angle end, Mid-range, Telephoto end d7 4.488 45.159 66.335 d15 62.784 22.113 0.937 d29 6.291 4.688 1.171 d32 64.037 65.641 69.158 d38 39.996 39.996 39.996 Wide-angle end, Mid-range, Telephoto end Focal length 207.5 309.0 380.8 F-number 4.1 4.1 4.1 Half-angle 5.95 4.01 3.25 Image height 21.635 21.635 21.635 Lens length 368.37 368.37 368.37 BF 39.996 39.996 39.996 (Numerical Example 4) Face number rd nd νd 1 378.419 7.846 1.487 70.2 2 -1795.818 0.300 3 124.251 13.930 1.434 95.1 4 354.219 13.144 5 180.269 2.400 1.816 46.6 6 84.396 16.515 1.497 81.5 7 281.924 (variable) 8 75.201 9.000 1.487 70.2 9 461.766 20.035 10 157.306 1.800 1.640 60.1 11 42.872 7.973 12 -276.069 1.70 1.497 81.5 13 78.946 4.400 14 63.389 4.46 1.689 31.1 15 230.448 4.234 16 -99.501 1.50 1.729 54.7 17 608.107 (variable) 18 151.875 3.195 1.497 81.5 19 -6463.820 0.136 20 53.310 6.003 1.497 81.5 21 325.154 19.982 22 (aperture) ∞ -0.011 23 65.814 3.572 1.497 81.5 24 179.245 6.029 25 -387.556 2.000 1.816 46.6 26 46.392 3.924 27 92.105 1.80 1.800 29.8 28 64.222 6.992 1.497 81.5 29 -136.344 0.150 30 96.638 2.687 1.816 46.6 31 330.341 0.850 32 40.899 4.482 1.497 81.5 33 192.210 (Variable) 34 174.243 4.01 1.808 22.8 35 -124.275 1.300 1.905 35 36 52.408 2.000 37 891.396 1.500 1.816 46.6 38 79.504 (Variable) 39 79.836 12.286 1.648 33.8 40 -52.481 1.980 1.923 18.9 41 -80.657 26.083 42 -58.066 1.981 1.729 54.7 43 -410.070 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d7 3.056 37.811 79.339 d17 77.263 42.508 0.980 d33 5.122 5.699 0.279 d38 62.439 61.862 67.282 d43 39.998 39.998 39.998 Wide-angle end, Mid-range, Telephoto end Focal length 207.0 306.0 487.9 F-number 4.1 4.1 4.1 Half-angle 5.97 4.04 2.54 Image height 21.635 21.635 21.635 Lens length 410.05 410.05 410.05 BF 39.998 39.998 39.998 (Numerical Example 5) Face number rd nd νd 1 286.607 6.840 1.487 70.2 2 -1463.003 0.300 3 111.246 11.738 1.434 95.1 4 1749.209 27.948 5 98.098 13.041 1.497 81.5 6 -545.177 2.400 1.735 49.8 7 81.765 (variable) 8 83.258 1.800 1.750 35.3 9 33.749 4.066 1.816 46.6 10 42.417 7.154 11 -180.665 1.700 1.528 76.5 12 113.470 0.466 13 61.787 5.339 1.789 28.4 14 581.763 2.802 15 -105.706 1.500 1.497 81.5 16 204.478 (variable) 17 138.794 3.690 1.497 81.5 18 -876.951 0.136 19 58.535 5.262 1.497 81.5 20 452.891 19.982 21 (aperture) ∞ 0.500 22 71.448 2.623 1.497 81.5 23 127.256 5.249 24 -349.339 2.000 1.695 42.2 25 49.166 2.305 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 41.541 4.323 1.497 81.5 32 340.942 (variable) 33 385.851 3.853 1.893 20.4 34 -148.541 1.300 1.852 40.8 35 56.735 2.000 36 1096.989 2.000 1.852 40.8 37 62.616 (Variable) 38 79.788 13.608 1.603 38.0 39 -46.706 1.980 1.808 22.8 40 -73.893 27.238 41 -55.378 1.981 1.729 54.7 42 -189.233 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d 7 7.219 44.774 63.898 d16 61.961 21.661 0.969 d32 1.990 2.039 0.524 d37 56.507 59.203 62.285 d42 39.997 39.997 39.997 Wide-angle end, Mid-range, Telephoto end Focal length 200.1 309.0 386.1 F-number 4.1 4.1 4.1 Half-angle 6.17 4.01 3.21 Image height 21.635 21.635 21.635 Lens length 367.43 367.43 367.43 BF 39.997 39.997 39.997 (Numerical Example 6) Face number rd nd νd 1 283.661 6.931 1.487 70.2 2 -1412.95 0.300 3 119.771 10.893 1.434 95.1 4 1560.631 31.701 5 110.911 9.439 1.497 81.5 6 -568.7 2.400 1.735 49.8 7 93.198 (variable) 8 92.995 1.800 1.750 35.3 9 34.391 4.274 1.816 46.6 10 44.216 7.528 11 -180.117 1.700 1.528 76.5 12 121.148 0.484 13 65.973 5.511 1.789 28.4 14 1359.812 2.721 15 -105.632 1.500 1.497 81.5 16 399.221 (variable) 17 178.567 3.256 1.497 81.5 18 -1602.05 0.136 19 58.361 5.561 1.497 81.5 20 400.782 19.982 21 (aperture) ∞ 0.500 22 75.552 3.042 1.497 81.5 23 174.59 8.414 24 -270.101 2.000 1.695 42.2 25 48.432 2.417 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 40.329 4.723 1.497 81.5 32 484.054 (variable) 33 415.075 2.862 1.893 20.4 34 -144.135 1.300 1.852 40.8 35 53.349 2.000 36 1181.562 2.000 1.852 40.8 37 65.624 (Variable) 38 75.851 14.180 1.603 38.0 39 -46.623 1.980 1.808 22.8 40 -74.984 28.545 41 -52.714 1.981 1.729 54.7 42 -198.68 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d 7 3.802 39.570 72.602 d16 56.962 27.574 0.979 d32 3.329 2.974 0.419 d37 8.410 8.764 11.319 d42 39.993 39.993 39.993 Wide-angle end, Mid-range, Telephoto end Focal length 206.1 285.0 386.5 F-number 4.1 4.1 4.1 Half-angle 5.99 4.34 3.2 Image height 21.635 21.635 21.635 Lens length: 367.18 373.56 380.00 BF 39.993 39.993 39.993 (Numerical Examples 1-2) Face number rd nd νd 1 273.176 7.081 1.487 70.2 2 -1361.262 0.300 3 113.868 11.427 1.434 95.1 4 1751.273 28.392 5 104.514 9.931 1.497 81.5 6 -530.570 2.400 1.735 49.8 7 87.663 5.082 8 85.600 1.800 1.750 35.3 9 34.633 4.083 1.816 46.6 10 43.494 7.461 11 -198.501 1.700 1.528 76.5 12 110.708 0.473 13 63.583 5.393 1.789 28.4 14 602.245 2.877 15 -107.425 1.500 1.497 81.5 16 331.917 (variable) 17 153.599 3.301 1.497 81.5 18 21625.358 0.136 19 57.826 5.529 1.497 81.5 20 398.525 19.982 21 (aperture) ∞ 0.500 22 76.071 2.773 1.497 81.5 23 149.129 7.313 24 -306.956 2.000 1.695 42.2 25 48.393 2.415 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 40.630 4.639 1.497 81.5 32 419.832 (variable) 33 373.891 3.439 1.893 20.4 34 -145.171 1.300 1.852 40.8 35 55.255 2.000 36 993.429 2.000 1.852 40.8 37 63.079 (Variable) 38(Ext) 44.327 3.841 1.497 81.5 39(Ext) -344.994 2.227 40(Ext) 19.184 4.493 1.517 52.4 41(Ext) 46.384 1.150 1.883 40.8 42(Ext) 19.213 10.053 43(Ext) -281.796 0.950 1.905 35 44(Ext) 21.867 6.568 1.738 32.3 45(Ext) -46.055 0.950 1.804 46.6 46(Ext) 81.160 0.497 47(Ext) 48.448 7.081 1.613 44.3 48(Ext) -23.570 1.050 1.595 67.7 49(Ext) 136.359 (Variable) 50 76.040 13.902 1.603 38 51 -46.009 1.980 1.808 22.8 52 -72.949 25.690 53 -54.037 1.981 1.729 54.7 54 -229.615 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d7 5.082 36.908 66.439 d16 62.324 30.499 0.967 d32 3.399 3.021 0.413 d37 8.498 8.876 11.484 d49 11.135 11.135 11.135 d54 39.994 39.994 39.994 Wide-angle end, Mid-range, Telephoto end Focal length 290.4 401.6 543.2 F-number 5.8 5.8 5.8 Half-angle 4.26 3.08 2.28 Image height 21.635 21.635 21.635 Lens length 367.62 367.62 367.62 BF 39.994 39.994 39.994 (Numerical Example 3-2) Face number rd nd νd 1 217.020 7.911 1.487 70.2 2 -2114.635 0.300 3 108.060 10.941 1.434 95.1 4 799.040 24.642 5 90.882 10.000 1.497 81.5 6 -6626.810 2.400 1.773 49.6 7 77.778 (variable) 8 119.161 1.800 2.001 29.1 9 60.733 6.079 10 -255.201 1.700 1.497 81.5 11 111.954 2.949 12 83.304 4.599 1.855 24.8 13 562.828 3.746 14 -99.723 1.500 1.497 81.5 15 -508.786 62.784 16 84.172 (variable) 1.497 81.5 17 3474.868 0.500 18 80.008 3.901 1.497 81.5 19 250.578 29.600 20 (aperture) ∞ 4.369 21 -271.566 2.000 1.673 38.1 22 59.960 4.617 23 92.105 1.800 1.917 31.6 24 64.222 6.992 1.497 81.5 25 -136.344 0.150 26 96.638 2.687 1.773 49.6 27 330.341 0.999 28 52.525 3.596 1.595 67.7 29 149.095 (variable) 30 481.601 2.203 1.847 23.8 31 -148.197 1.300 1.852 40.8 32 52.346 (Variable) 33(Ext) 832.656 2.664 1.673 32.1 34(Ext) -192.540 0.962 35(Ext) 22.864 3.891 1.595 67.7 36(Ext) 34.795 1.150 1.706 30.2 37(Ext) 26.166 15.829 38(Ext) 183.567 0.950 2.001 25.5 39(Ext) 16.536 9.776 1.789 28.4 40(Ext) -29.622 0.950 1.883 40.8 41(Ext) 53.989 0.904 42(Ext) 34.486 9.907 1.581 40.8 43(Ext) -18.478 1.050 1.595 67.7 44(Ext) 85.879 (Variable) 45* 164.208 0.100 1.516 52.2 46 132.826 9.566 1.728 28.5 47 -45.927 1.500 1.893 20.4 48 -96.765 29.578 49 -37.293 1.500 1.603 65.4 50 -90.046 (variable) Image plane ∞ K c4 c6 d45 0 1.359E-06 3.603E-10 (c8 and later 0) Wide-angle end, Mid-range, Telephoto end d7 4.488 45.159 66.335 d15 62.784 22.113 0.937 d29 6.291 4.688 1.171 d32 14.043 15.647 19.163 d44 1.961 1.961 1.961 d50 39.995 39.995 39.995 Wide-angle end, Mid-range, Telephoto end Focal length 295.9 440.8 543.2 F-number 5.9 5.8 5.9 Half-angle 4.18 2.81 2.28 Image height 21.635 21.635 21.635 Lens length 368.37 368.37 368.37 BF 39.995 39.995 39.995 (Numerical Example 4-2) Face number rd nd νd 1 378.419 7.846 1.487 70.2 2 -1795.818 0.300 3 124.251 13.930 1.434 95.1 4 354.219 13.144 5 180.269 2.400 1.816 46.6 6 84.396 16.515 1.497 81.5 7 281.924 (variable) 8 75.201 9.000 1.487 70.2 9 461.766 20.035 10 157.306 1.800 1.640 60.1 11 42.872 7.973 12 -276.069 1.700 1.497 81.5 13 78.946 4.400 14 63.389 4.462 1.689 31.1 15 230.448 4.234 16 -99.501 1.500 1.729 54.7 17 608.107 (variable) 18 151.875 3.195 1.497 81.5 19 -6463.820 0.136 20 53.310 6.003 1.497 81.5 21 325.154 19.982 22 (aperture) ∞ -0.011 23 65.814 3.572 1.497 81.5 24 179.245 6.029 25 -387.556 2.000 1.816 46.6 26 46.392 3.924 27 92.105 1.800 1.800 29.8 28 64.222 6.992 1.497 81.5 29 -136.344 0.150 30 96.638 2.687 1.816 46.6 31 330.341 0.850 32 40.899 4.482 1.497 81.5 33 192.210 (Variable) 34 174.243 4.011 1.808 22.8 35 -124.275 1.300 1.905 35 36 52.408 2.000 37 891.396 1.500 1.816 46.6 38 79.504 (Variable) 39(Ext) 24.675 6.188 1.622 53.2 40(Ext) -184.787 0.300 41(Ext) 429.639 4.984 1.595 67.7 42(Ext) -28.938 1.150 1.622 53.2 43(Ext) 31.228 8.578 44(Ext) -56.537 0.950 2.001 29.1 45(Ext) 18.702 10.795 1.648 33.8 46(Ext) -15.250 0.950 1.729 54.7 47(Ext) -63.757 0.499 48(Ext) 45.665 10.512 1.517 52.4 49(Ext) -18.772 1.050 1.497 81.5 50 80.729 (variable) 51 79.836 12.286 1.648 33.8 52 -52.481 1.980 1.923 18.9 53 -80.657 26.083 54 -58.066 1.981 1.729 54.7 55 -410.070 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d7 3.056 37.811 79.339 d17 77.263 42.508 0.980 d33 5.122 5.699 0.279 d38 12.444 11.868 17.287 d50 4.039 4.039 4.039 d55 39.998 39.998 39.998 Wide-angle end, Mid-range, Telephoto end Focal length 288.1 425.7 678.9 F-number 5.7 5.7 5.7 Half-angle 4.30 2.91 1.83 Image height 21.635 21.635 21.635 Lens length 410.05 410.05 410.05 BF 39.998 39.998 39.998 (Numerical Example 5-2) Face number rd nd νd 1 286.607 6.840 1.487 70.2 2 -1463 0.300 3 111.246 11.738 1.434 95.1 4 1749.209 27.948 5 98.098 13.041 1.497 81.5 6 -545.177 2.400 1.735 49.8 7 81.765 (variable) 8 83.258 1.800 1.750 35.3 9 33.749 4.066 1.816 46.6 10 42.417 7.154 11 -180.665 1.700 1.528 76.5 12 113.47 0.466 13 61.787 5.339 1.789 28.4 14 581.763 2.802 15 -105.706 1.500 1.497 81.5 16 204.478 (variable) 17 138.794 3.690 1.497 81.5 18 -876.951 0.136 19 58.535 5.262 1.497 81.5 20 452.891 19.982 21 (Aperture) ∞ 0.500 22 71.448 2.623 1.497 81.5 23 127.256 5.249 24 -349.339 2.000 1.695 42.2 25 49.166 2.305 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 41.541 4.323 1.497 81.5 32 340.942 (variable) 33 385.851 3.853 1.893 20.4 34 -148.541 1.300 1.852 40.8 35 56.735 2.000 36 1096.989 2.000 1.852 40.8 37 62.616 (variable) 38 (Ext) 44.379 3.741 1.497 81.5 39 (Ext) -292.043 2.160 40 (Ext) 19.215 4.687 1.517 52.4 41 (Ext) 51.561 1.150 1.883 40.8 42 (Ext) 19.175 8.692 43(Ext) -293.666 0.950 1.905 35.0 44(Ext) 23.442 6.638 1.738 32.3 45(Ext) -48.256 0.950 1.804 46.6 46(Ext) 90.003 0.400 47(Ext) 50.373 7.573 1.613 44.3 48(Ext) -23.216 1.050 1.595 67.7 49(Ext) 126.385 (Variable) 50 79.788 13.608 1.603 38.0 51 -46.706 1.980 1.808 22.8 52 -73.893 27.238 53 -55.378 1.981 1.729 54.7 54 -189.233 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d 7 7.219 44.774 63.898 d16 61.961 21.661 0.969 d32 1.990 2.039 0.524 d37 6.512 9.209 12.291 d49 12.003 12.003 12.003 d54 39.997 39.997 39.997 Wide-angle end, Mid-range, Telephoto end Focal length 278.4 429.9 537.2 F-number 5.7 5.7 5.7 Half-angle 4.44 2.88 2.31 Image height 21.635 21.635 21.635 Lens length 367.43 367.43 367.43 BF 39.997 39.997 39.997 (Numerical Example 6-2) Surface number r d nd νd 1 283.661 6.931 1.487 70.2 2 -1412.95 0.300 3 119.771 10.893 1.434 95.1 4 1560.631 31.701 5 110.911 9.439 1.497 81.5 6 -568.7 2.400 1.735 49.8 7 93.198 (Variable) 8 92.995 1.800 1.750 35.3 9 34.391 4.274 1.816 46.6 10 44.216 7.528 11 -180.117 1.700 1.528 76.5 12 121.148 0.484 13 65.973 5.511 1.789 28.4 14 1359.812 2.721 15 -105.632 1.500 1.497 81.5 16 399.221 (Variable) 17 178.567 3.256 1.497 81.5 18 -1602.05 0.136 19 58.361 5.561 1.497 81.5 20 400.782 19.982 21 (Aperture) ∞ 0.500 22 75.552 3.042 1.497 81.5 23 174.59 8.414 24 -270.101 2.000 1.695 42.2 25 48.432 2.417 26 92.105 1.800 1.800 29.8 27 64.222 6.992 1.497 81.5 28 -136.344 0.150 29 96.638 2.687 1.816 46.6 30 330.341 1.000 31 40.329 4.723 1.497 81.5 32 484.054 (variable) 33 415.075 2.862 1.893 20.4 34 -144.135 1.300 1.852 40.8 35 53.349 2.000 36 1181.562 2.000 1.852 40.8 37 65.624 (Variable) 38(Ext) 46.084 3.731 1.497 81.5 39(Ext) -272.994 1.907 40(Ext) 18.946 4.984 1.517 52.4 41(Ext) 52.322 1.150 1.883 40.8 42(Ext) 18.591 7.882 43(Ext) -205.37 0.950 1.905 35.0 44(Ext) 27.464 6.147 1.738 32.3 45(Ext) -51.367 0.950 1.804 46.6 46(Ext) 117.778 0.369 47(Ext) 54.679 7.768 1.613 44.3 48(Ext) -22.944 1.050 1.595 67.7 49 (Ext) 159.66 (Variable) 50 75.851 14.180 1.603 38.0 51 -46.623 1.980 1.808 22.8 52 -74.984 28.545 53 -52.714 1.981 1.729 54.7 54 -198.68 (variable) Image plane ∞ Wide-angle end, Mid-range, Telephoto end d 7 3.802 39.570 72.602 d16 56.962 27.574 0.979 d32 3.329 2.974 0.419 d37 8.410 8.764 11.319 d49 13.108 13.108 13.108 d54 39.993 39.993 39.993 Wide-angle end, Mid-range, Telephoto end Focal length 278.7 385.4 522.5 F-number 5.5 5.5 5.5 Half-angle 4.44 3.21 2.37 Image height 21.635 21.635 21.635 Lens length: 367.18 373.56 380.00 BF 39.993 39.993 39.993 The numerical values ​​of the conditional expressions in each numerical example are summarized in Table 1 below.

[0059] [Table 1]

[0060] (Imaging device) Next, with reference to Figure 18, an imaging device equipped with the optical system of each embodiment will be described. Figure 18 is a schematic diagram of an imaging device (digital still camera) 10 using any of the optical systems 1a to 1f of Embodiments 1 to 6 as the imaging optical system.

[0061] In Figure 18, 13 is the camera body, and 11 is the imaging optical system (interchangeable lens) composed of one of the optical systems 1a to 1f from Examples 1 to 6. 12 is an image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor, which is built into the camera body 13 and receives light from the imaging optical system 11 (the optical image formed by the imaging optical system 11) and converts it into photoelectric energy. The camera body 13 may be a so-called single-lens reflex camera with a quick-turn mirror, or a so-called mirrorless camera without a quick-turn mirror.

[0062] According to each embodiment, it is possible to provide a compact, high-performance zoom lens and imaging device that can accommodate an extender group.

[0063] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence.

[0064] For example, the zoom lens in each embodiment consists of five lens groups other than the extender group EXT, but is not limited to this, and there may be six or more lens groups other than the extender group EXT. [Explanation of symbols]

[0065] 1a~1f Optical system (zoom lens) B1 First lens group B2 Second lens group B3 Third lens group B4 4th lens group B5 5th lens group EXT Extender Group

Claims

1. A zoom lens consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, an extender group, and a fifth lens group with positive refractive power, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming. The focal length of the zoom lens changes as the extender group is inserted into or removed from the optical path. The lens positioned closest to the object in the first lens group has a positive refractive power. The first lens group has a cemented lens, When the focal length of the first lens group is f1, the focal length of the zoom lens at its telephoto end is ft, the focal length of the second lens group is f2, the distance along the optical axis from the fifth lens group to the fourth lens group when in focus at the telephoto end is D, the distance along the optical axis from the lens surface closest to the object to the image plane when in focus at the telephoto end is TL, the focal length of the third lens group is f3, and the focal length of the fourth lens group is f4, 0.60<f1 / ft<1.50 -3.90<f1 / f2<-1.00 0.10<D / TL<0.30 -5.00<f3 / f4<-1.00 A zoom lens characterized by satisfying the following conditional equation.

2. The zoom lens according to claim 1, characterized in that the fifth lens group remains stationary during zooming.

3. -0.50<f4 / ft<-0.05 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

4. The zoom lens according to any one of claims 1 to 3, characterized in that the fifth lens group comprises at least one positive lens and at least one negative lens.

5. The zoom lens according to any one of claims 1 to 4, characterized in that the fifth lens group comprises a cemented lens formed by joining a positive lens and a negative lens, and a negative lens positioned on the image side of the cemented lens.

6. 0.10<f5 / ft<2.00 A zoom lens according to any one of claims 1 to 5, characterized in that it satisfies the following conditional expression.

7. The zoom lens according to any one of claims 1 to 6, characterized in that the fourth lens group moves when focusing.

8. The zoom lens according to any one of claims 1 to 7, characterized in that the second lens group has at least four lenses.

9. The zoom lens according to any one of claims 1 to 8, characterized in that the second lens group moves toward the image side when zooming from the wide-angle end to the telephoto end.

10. An imaging device characterized by having a zoom lens according to any one of claims 1 to 9 and an image sensor that receives an image formed by the zoom lens.

Images