Zoom lens and imaging device having the same

Abstract

To provide a compact zoom lens that offers high magnification when changing from the wide-angle end to the telephoto end. [Solution] A zoom lens comprising a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, arranged in order from the object side to the image side, wherein the distance between adjacent lens groups changes when zooming is performed, the first to third lens groups each have one or more aspherical lenses made of resin material, the first lens group remains stationary with respect to the image plane when zooming from the wide-angle end to the telephoto end, and satisfying a predetermined condition when the distance on the optical axis from the object-side lens surface of the lens placed closest to the object in the first lens group to the image plane is TL, the maximum image height is imgH, the focal length of the first lens group is f1, and the focal length of the third lens group is f3.

Description

Technical Field

[0001] The disclosure of this specification relates to a zoom lens, and is particularly suitable for imaging devices such as cameras for smartphones, still cameras, video cameras, digital still cameras, in-vehicle cameras, surveillance cameras, etc.

Background Art

[0002] Conventionally, as a zoom lens used in imaging devices such as cameras for smartphones and cameras for photography, a high-quality zoom lens that is small in size and has various aberrations well corrected has been required. Patent Document 1 discloses a zoom lens having a first lens group with a negative refractive power, a second lens group with a positive refractive power, and a third lens group with a negative refractive power in order from the object side to the image side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a small-sized zoom lens, it is required to have a high magnification in the zooming from the wide-angle end to the telephoto end, that is, a high magnification that covers a wide range of focal lengths. In order to realize a small-sized and high-magnification zoom lens, it is necessary to appropriately set various conditions such as the refractive power and arrangement of each lens group constituting the zoom lens.

Means for Solving the Problems

[0005] A zoom lens as one aspect of the present invention comprises a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, arranged sequentially from the object side to the image side, wherein the distance between adjacent lens groups changes during magnification, and each of the first to third lens groups has one or more aspherical lenses made of resin material, and the first lens group remains stationary with respect to the image plane during magnification from the wide-angle end to the telephoto end, and when the distance on the optical axis from the object-side lens surface of the lens furthest to the object side in the first lens group to the image plane is TL, the maximum image height is imgH, the focal length of the first lens group is f1, and the focal length of the third lens group is f3, 0.11 <imgH / TL<0.20 1.20 <f1 / f3<5.00 It is characterized by satisfying the following conditional expression.

[0006] Furthermore, as another aspect of the present invention, a zoom lens comprises a prism having a reflective surface arranged sequentially from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, wherein the distance between adjacent lens groups changes when the zoom is changed, the first lens group remains stationary with respect to the image plane when the zoom is changed from the wide-angle end to the telephoto end, and when the distance on the optical axis from the object-side lens surface of the lens positioned closest to the object in the first lens group to the image plane is TL, and the maximum image height is imgH, 0.11 <imgH / TL<0.20 It is characterized by satisfying the following conditional expression. [Effects of the Invention]

[0007] This makes it possible to provide a compact zoom lens that has a high magnification when changing from the wide-angle end to the telephoto end. [Brief explanation of the drawing]

[0008] [Figure 1] Schematic diagram of the optical system in each embodiment [Figure 2] Lens cross-sectional view at the wide-angle and telephoto ends of Example 1 [Figure 3]Aberration diagrams at the wide-angle end and telephoto end of Example 1 (A) [Figure 4] Lens cross-sectional view at the wide-angle and telephoto ends of Example 2 [Figure 5] Aberration diagrams at the wide-angle end and telephoto end of Example 2 (A) [Figure 6] Lens cross-sectional view at the wide-angle and telephoto ends of Example 3 [Figure 7] Aberration diagrams at the wide-angle end and telephoto end of Example 3 (A) [Figure 8] Lens cross-sectional view at the wide-angle and telephoto ends of Example 4 [Figure 9] Aberration diagrams at the wide-angle end and telephoto end of Example 4 (A) [Figure 10] Lens cross-sectional view at the wide-angle and telephoto ends of Example 5 [Figure 11] Aberration diagrams at the wide-angle end and telephoto end of Example 5 (A) [Figure 12] Schematic diagram of the main components of the imaging device. [Modes for carrying out the invention]

[0009] The embodiments disclosed herein will be described in detail below with reference to the drawings. Note that the drawings may be drawn to a different scale than the actual scale for convenience. In addition, the same reference numeral is used for the same components in each drawing, and redundant explanations are omitted. In the following embodiments, the wide-angle end and the telephoto end refer to the zoom positions when the lens group for variable magnification is located at both ends of the range in which it can move along the optical axis due to the mechanism.

[0010] Figure 1 shows a schematic diagram of the optical system used in the zoom lens of each embodiment, with the optical system used in Embodiment 1 shown as a representative example. In Figure 1, SP is the aperture diaphragm that determines the light beam at the open F-number (Fno). IP is the image plane, and when used as the imaging optical system for a video camera or digital still camera, it is where the imaging surface of a solid-state image sensor or photoelectric conversion element such as a CCD sensor or CMOS sensor is placed. When used as the imaging optical system for a silver halide film camera, it is where the photosensitive surface corresponding to the film surface is placed. P is a prism with a reflective surface, and it plays the role of bending the light beam.

[0011] Figures 2, 4, 6, 8, and 10 are cross-sectional views of the zoom lens L0 at its wide-angle and telephoto ends, respectively, according to Examples 1 to 5. In each cross-sectional view, IP represents the image plane. The zoom lens L0 according to each example is used in an imaging device, and the imaging surface of a solid-state image sensor such as a CCD sensor or CMOS sensor, or a photoelectric conversion element, is positioned at the location of the image plane IP. The zoom lens L0 of each example may also be used as the photographic optical system of a silver halide film camera, in which case a photosensitive surface corresponding to the film plane is positioned on the image plane IP. In addition, in each cross-sectional view, SP represents the aperture diaphragm that determines the light beam at the open F number.

[0012] In each sectional view, the left side is the object side and the right side is the image side. The zoom lens L0 of each embodiment is suitable for imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide film cameras, surveillance cameras, in-vehicle cameras, etc. In the zoom lens L0, the distance between adjacent lens groups changes during zooming. That is, in this specification, a lens group refers to a group of lenses that move integrally during zooming or a group of lenses that remain stationary during zooming. Note that a lens group may be composed of one lens or a plurality of lenses. Also, each lens group may include an aspherical lens, a Fresnel lens, a metalens, a diffractive optical element, etc. Also, each lens group may include an aperture stop SP. When an optical member having a reflecting surface is disposed on the object side of the first lens group L1, the optical member having the reflecting surface shall not be included in the lens group. Examples of the optical member having a reflecting surface include, for example, a prism P, etc.

[0013] Figures 3, 5, 7, 9, and 11 are longitudinal aberration diagrams of the zoom lens L0 according to Embodiments 1 to 5, respectively. In each aberration diagram, the spherical aberration diagram, the astigmatism diagram, the distortion diagram, and the chromatic aberration diagram are shown in order from the left side. Also, in each longitudinal aberration diagram, (A) shows the longitudinal aberration diagram at the wide-angle end, and (B) shows the longitudinal aberration diagram at the telephoto end.

[0014] In each longitudinal aberration diagram, Fno is the F-number, ω is the semi-field angle (°), and it is the field angle based on the ray tracing value. In the spherical aberration diagram, the solid line d shows the amount of spherical aberration for the d-line (wavelength 587.56 nm), and the two-dot chain line g shows the amount of spherical aberration for the g-line (wavelength 435.835 nm). In the astigmatism diagram, the solid line ΔS shows the amount of astigmatism for the d-line on the sagittal image plane, and the broken line ΔM shows the amount of astigmatism for the d-line on the meridional image plane. In the distortion diagram, the solid line shows the amount of distortion for the d-line. In the longitudinal chromatic aberration diagram, the two-dot chain line g shows the amount of chromatic aberration for the g-line.

[0015] Next, the characteristic configurations of the zoom lens L0 of each embodiment will be described.

[0016] The zoom lens L0 of each embodiment has a first lens group L1 with a negative refractive power, a second lens group L2 with a positive refractive power, and a third lens group L3 with a negative refractive power, in order from the object side. With such a configuration, it is possible to secure a high magnification during zooming from the wide-angle end to the telephoto end while securing a wide angle of view in the wide-angle range.

[0017] The zoom lens L0 of each embodiment includes at least one aspherical lens made of a resin material in each lens group. By adopting an aspherical lens, the number of lenses in the zoom lens L0 can be reduced, and miniaturization of the zoom lens L0 can be achieved.

[0018] In the zoom lens L0 of each embodiment, the distance between the lens groups changes during zooming from the wide-angle end to the telephoto end, and the first lens group L1 is stationary with respect to the image plane. By making the first lens group L1 stationary during zooming, the eccentricity of the first lens group L1 during zooming caused by manufacturing errors or the like is suppressed, and fluctuations in various aberrations due to the eccentricity are reduced.

[0019] Further, the zoom lens L0 of each embodiment is characterized by satisfying the following conditional expression (1) when the overall optical length of the zoom lens L0 is TL and the maximum image height is imgH. 0.11 < imgH / TL < 0.20 (1)

[0020] The conditional expression (1) defines the ratio of the maximum image height imgH to the overall optical length of the zoom lens L0. By satisfying the conditional expression (1), it is possible to achieve both high magnification and miniaturization of the zoom lens L0. Note that the maximum image height refers to the distance from the position where the peripheral light amount with respect to the vicinity of the optical axis on the image plane becomes 10% to the optical axis. Also, the overall optical length refers to the distance on the optical axis from the object-side lens surface of the lens disposed most on the object side in the first lens group L1 to the image plane IP.

[0021] If the upper limit of condition (1) is exceeded, the overall optical length becomes shorter, limiting the amount of movement of each lens during magnification, which is undesirable as it makes it difficult to increase the magnification of the zoom lens L0. If the lower limit of condition (1) is exceeded, the overall optical length becomes longer, which is undesirable as it makes the zoom lens L0 larger in the optical axis direction.

[0022] Furthermore, it is more preferable to set the numerical range of condition (1) to the range of condition (1a) below. 0.12 <imgH / TL<0.18 (1a)

[0023] Furthermore, it is even more preferable to set the numerical range of condition (1) to the range of condition (1b) below. 0.13 <imgH / TL<0.16 (1b)

[0024] With the above configuration, it is possible to realize a zoom lens L0 that is compact and has high optical performance while maintaining high magnification during zoom changes.

[0025] Next, we will describe the conditions that are preferable to satisfy in the zoom lens L0 of each embodiment.

[0026] The zoom lens L0 of each embodiment preferably satisfies one or more of the following conditional equations (2) to (23). In each conditional equation, the numerical values ​​are expressed as follows.

[0027] Let f1 be the focal length of the first lens group L1, f2 be the focal length of the second lens group L2, f3 be the focal length of the third lens group L3, fw be the total focal length of the zoom lens L0 at the wide-angle end, and ft be the total focal length of the zoom lens L0 at the telephoto end.

[0028] When changing magnification from the wide-angle end to the telephoto end, the amount of movement of the second lens group L2 along the optical axis is denoted as MD2, and the amount of movement of the third lens group L3 along the optical axis is denoted as MD3. However, the movement of each lens group is considered positive when it moves toward the object.

[0029] Let skw be the back focus at the wide-angle end, and skt be the back focus at the telephoto end.

[0030] Let Fnow be the F-number at the wide-angle end, and Fnot be the F-number at the telephoto end.

[0031] Let HOVw be the half-angle at the wide-angle end, and HOVt be the half-angle at the telephoto end.

[0032] In the first lens group L1, LD11 is defined as half the effective diameter of the object-side lens surface of the lens positioned closest to the object, and in the third lens group L3, LD3L is defined as half the effective diameter of the image-side lens surface of the lens positioned closest to the image.

[0033] Let SF11 be the shape factor of the lens closest to the object in the first lens group L1, and SF21 be the shape factor of the lens closest to the object in the second lens group L2. Similarly, let SF31 be the shape factor of the lens closest to the object in the third lens group L3, and SF3L be the shape factor of the lens closest to the image in the third lens group L3. Here, the shape factor SF is the shape factor of lens L, and is defined by the following equation, where fL is the focal length of lens L, R1 is the radius of curvature of the object-side lens surface, and R2 is the radius of curvature of the image-side lens surface. However, if the lens surface is aspherical, R represents the radius of the reference quadratic surface. sgn represents the sign function, taking +1 if fL is positive and -1 if fL is negative. SF = sgn(fL) × (R² + R¹) / (R² - R¹)

[0034] Let PL be the distance along the optical axis between the image-side lens surface of the prism P positioned on the object side of the first lens group L and the object-side lens surface of the lens positioned on the object side of the first lens group L1. 1.20 <f1 / f3<5.00 (2) 1.70 <ft / fw<2.50 (3) -2.10 <f1 / fw<-1.20 (4) -1.10 <f1 / ft<-0.50 (5) -6.00 <f1 / f2<-1.00 (6) -1.30 <f2 / f3<-0.30 (7) 0.60 <ft / TL<1.30 (8) 0.10 <MD2 / TL<0.35 (9) 0.10 <MD3 / TL<0.40 (10) 2.00 <Fnow<3.00 (11) 3.00 <Fnot<5.70 (12) 20.00 <TL×Fnot / imgH<35.00 (13) 0.12 <skw / TL<0.23 (14) 0.12 <skt / TL<0.46 (15) 0.30 <HOVt / HOVw<0.65 (16) 0.55 <LD11 / imgH<1.00 (17) 0.90 <LD11 / LD3L<1.40 (18) -12.00 <SF11<4.00 (19) -2.00 <SF21<1.00 (20) -5.00 <SF31<1.00 (21) -100.00 <SF3L<50.00 (22) 0.04 <PL / TL<0.07 (23)

[0035] Condition (2) specifies the focal length of the first lens group L1 and the focal length of the third lens group L3. By satisfying condition (2), it is possible to suppress changes in optical performance due to increased magnification and changes in magnification of the zoom lens L0.

[0036] If the refractive power exceeds the upper limit of condition (2), the refractive power of the third lens group L3 becomes too strong, making it difficult to correct the field curvature and chromatic aberration caused by the off-axis light beam of the third lens group L3, which is undesirable. If the refractive power falls below the lower limit of condition (2), the refractive power of the third lens group L3 becomes too weak, making it difficult to achieve high magnification, which is also undesirable.

[0037] Conditional equation (3) defines the ratio of the total focal length fw at the wide-angle end to the total focal length ft at the telephoto end, and is a condition for ensuring the zoom ratio in variable magnification.

[0038] If the upper limit of condition (3) is exceeded, it becomes difficult to suppress changes in optical performance due to magnification, and the zoom lens L0 becomes larger in the optical axis direction, which is undesirable. If the lower limit of condition (3) is exceeded, it becomes difficult to secure the zoom magnification, which is also undesirable.

[0039] Conditional equation (4) defines the ratio of the focal length of the first lens group L1 to the total focal length of the entire system at the wide-angle end, aiming to achieve both a wide angle of view at the wide-angle end and high optical performance.

[0040] If the upper limit of condition (4) is exceeded, the focal length of the first lens group L1 becomes longer relative to the total focal length of the system at the wide-angle end, making it difficult to secure a wide angle of view at the wide-angle end, which is undesirable. If the lower limit of condition (4) is exceeded, the refractive power of the first lens group L1 becomes stronger, causing strong field curvature and chromatic aberration, which is also undesirable.

[0041] Conditional equation (5) defines the ratio of the focal length of the first lens group L1 to the total focal length of the entire system at the telephoto end, aiming to achieve both a long focal length at the telephoto end and high optical performance.

[0042] If the upper limit of condition (5) is exceeded, the focal length of the first lens group L1 relative to the overall focal length of the system at the telephoto end becomes longer, making it easier to suppress the occurrence of aberrations in the first lens group L1. However, this requires increasing the refractive power of the second lens group L2, which leads to the occurrence of various aberrations such as spherical aberration, and is therefore undesirable. If the lower limit of condition (5) is exceeded, the refractive power of the first lens group L1 relative to the overall focal length of the system at the telephoto end becomes too strong, making it difficult to secure a long focal length at the telephoto end, which is also undesirable.

[0043] Conditional equation (6) defines the ratio of the focal length of the first lens group L1 to the focal length of the second lens group L2, and is a condition for achieving both miniaturization of the zoom lens L0 and suppression of changes in optical performance due to magnification.

[0044] If the value exceeds the upper limit of condition (6), the refractive power of the second lens group L2 becomes stronger than that of the first lens group L1, resulting in strong spherical aberration, which is undesirable. If the value falls below the lower limit of condition (6), the refractive power of the second lens group L2 becomes weaker than that of the first lens group L1, causing the zoom lens L0 to become larger in the optical axis direction, which is also undesirable.

[0045] Conditional equation (7) defines the ratio of the focal length of the second lens group L2 to the focal length of the third lens group L3, and is a condition for achieving both miniaturization of the entire system and suppression of changes in optical performance due to magnification.

[0046] If the refractive power exceeds the upper limit of condition (7), the refractive power of the third lens group L3 becomes stronger than that of the second lens group L2, which is undesirable because it causes strong aberrations such as field curvature in the third lens group L3. If the refractive power falls below the lower limit of condition (7), the refractive power of the third lens group L3 becomes weaker than that of the second lens group L2, which is undesirable because it makes it difficult to achieve both miniaturization of the entire system and high magnification.

[0047] Conditional equation (8) defines the ratio of the total focal length of the system to the total optical length of the system at the telephoto end, and is a condition for achieving both miniaturization of the system and high optical performance.

[0048] If the upper limit of condition (8) is exceeded, the overall focal length of the system at the telephoto end becomes long, which is undesirable because it causes strong spherical aberration and axial chromatic aberration. If the lower limit of condition (8) is exceeded, the focal length at the telephoto end becomes short, which is undesirable because it causes the zoom lens L0 to become larger in the optical axis direction.

[0049] Conditional equation (9) defines the ratio of the amount of movement of the second lens group L2 along the optical axis to the total optical length of the entire system when changing magnification from the wide-angle end to the telephoto end. This condition is necessary to achieve both high magnification and suppression of changes in optical performance during magnification.

[0050] If the upper limit of condition (9) is exceeded, the distance the second lens group L2 moves during magnification becomes longer, resulting in a large change in optical performance during magnification, which is undesirable. If the lower limit of condition (9) is exceeded, the amount of movement of the second lens group L2 during magnification becomes smaller, making it difficult to secure a long focal length at the telephoto end, which is also undesirable.

[0051] Conditional equation (10) defines the ratio of the distance the third lens group L3 moves along the optical axis to the total optical length of the entire system when changing magnification from the wide-angle end to the telephoto end. This condition is necessary to achieve both high magnification and suppression of changes in optical performance during magnification.

[0052] If the upper limit of condition (10) is exceeded, the amount of movement of the third lens group L3 on the optical axis during magnification becomes large, which is undesirable because it leads to a large change in optical performance during magnification. If the lower limit of condition (10) is exceeded, the amount of movement of the third lens group L3 on the optical axis during magnification becomes small, which is undesirable because it makes it difficult to secure a long focal length at the telephoto end.

[0053] Conditional equation (11) specifies the F-number at the wide-angle end.

[0054] If the upper limit of condition (11) is exceeded, the amount of light incident on the image plane IP decreases, making the subject more prone to blurring during shooting, which is undesirable. If the lower limit of condition (11) is exceeded, the diameter of the lens in the second lens group L2 increases, causing the zoom lens L0 to become larger in the radial direction, which is also undesirable. Furthermore, aberrations such as spherical aberration and axial chromatic aberration occur, which is also undesirable.

[0055] Conditional equation (12) specifies the F-number at the telephoto end.

[0056] If the light level exceeds the upper limit of condition (12), or falls below the lower limit of condition (12), the amount of light incident on the image plane IP decreases, making the subject more prone to blurring during shooting, which is undesirable. The diameter of the lens in the first lens group L1 increases, and the zoom lens L0 becomes larger in the radial direction, which is undesirable. Furthermore, aberrations such as spherical aberration and axial chromatic aberration occur, which is undesirable.

[0057] Conditional equation (13) defines the ratio of the product of the optical length of the zoom lens L0 and the F-number at the telephoto end to the maximum image height, and is a condition for achieving both miniaturization of the entire system and brightness at the telephoto end.

[0058] If the value exceeds the upper limit of condition equation (13), it is advantageous for correcting spherical aberration and axial chromatic aberration mainly caused by axial light beam at the telephoto end, but it is undesirable because it makes it difficult to miniaturize the entire system and ensure brightness at the telephoto end. If the value falls below the lower limit of condition equation (13), it is advantageous for miniaturizing the entire system and ensuring brightness at the telephoto end, but it is undesirable because it makes it difficult to correct spherical aberration and axial chromatic aberration mainly caused by axial light beam at the telephoto end.

[0059] Conditional equation (14) defines the ratio of the back focus at the wide-angle end to the total optical length of the entire system, and is a condition for achieving both miniaturization of the entire system and securing the travel distance of the lens group that moves during magnification.

[0060] If the value exceeds the upper limit of condition (14), the back focus relative to the total optical length becomes long, making it difficult to secure the necessary distance along the optical axis for the lens group that moves during magnification, which is undesirable. If the value falls below the lower limit of condition (14), the back focus becomes short, making it difficult to properly position components such as filters, which is also undesirable.

[0061] Conditional equation (15) defines the ratio of the back focus at the telephoto end to the total optical length of the entire system, and is a condition for achieving both miniaturization of the entire system and securing the travel distance of the lens group that moves during magnification.

[0062] If the value exceeds the upper limit of condition (15), the back focus becomes long relative to the total optical length, making it difficult to secure the necessary distance along the optical axis for the lens group that moves during magnification, which is undesirable. If the value falls below the lower limit of condition (15), the back focus becomes short, making it difficult to properly position components such as filters on the image plane side, which is also undesirable.

[0063] Conditional equation (16) defines the ratio of the half-angle of view at the wide-angle end to the half-angle of view at the telephoto end.

[0064] If the upper limit of condition (16) is exceeded, the difference in angle of view between the wide-angle and telephoto ends becomes too large, which is undesirable because it causes the zoom lens L0 to become larger in the optical axis direction. If the lower limit of condition (16) is exceeded, the difference in angle of view between the wide-angle and telephoto ends becomes too small, which is undesirable because it makes it difficult to increase the magnification of the zoom lens L0.

[0065] Conditional equation (17) defines the ratio of half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group L1 to the maximum image height imgH.

[0066] If the upper limit of condition (17) is exceeded, the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group L1 becomes large relative to the maximum image height, which is undesirable because it causes the zoom lens L0 to become larger in the optical axis direction. If the lower limit of condition (17) is exceeded, the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group L1 becomes small, which is undesirable because it causes the F-number to become large at the telephoto end.

[0067] Conditional equation (18) specifies the ratio of half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group L1 to half the effective diameter of the image-side lens surface of the lens positioned closest to the image in the third lens group L3.

[0068] If the upper limit of condition (18) is exceeded, the effective diameter of the object-side lens surface of the lens furthest to the image in the third lens group L3 becomes larger than the effective diameter of the image-side lens surface of the lens furthest to the image in the third lens group L3, which is undesirable because it causes the zoom lens L0 to become larger in the optical axis direction. If the lower limit of condition (18) is exceeded, the effective diameter of the object-side lens surface of the lens furthest to the image in the third lens group L3 becomes smaller than the effective diameter of the image-side lens surface of the lens furthest to the image in the third lens group L3, which is undesirable because it causes the F-number to become larger at the telephoto end.

[0069] Conditional equation (19) is an equation that specifies the shape factor of the lens positioned closest to the object in the first lens group L1.

[0070] If the upper limit of condition (19) is exceeded, the curvature of the object-side lens surface of the lens positioned closest to the object in the first lens group L1 becomes large, making it difficult to suppress field curvature caused by off-axis light beams at the wide-angle end, which is undesirable. If the lower limit of condition (19) is fallen below, the curvature of the object-side lens surface of the lens becomes small, making it difficult to correct spherical aberration caused by on-axis light beams, which is also undesirable.

[0071] Conditional equation (20) is an equation that specifies the shape factor of the lens positioned closest to the object in the second lens group L2.

[0072] If the upper limit of condition (20) is exceeded, the curvature of the object-side lens surface of the lens positioned closest to the object in the second lens group L2 becomes large, making it difficult to suppress field curvature caused by off-axis light beams at the wide-angle end, which is undesirable. If the lower limit of condition (20) is fallen below, the curvature of the object-side lens surface of the lens becomes small, making it difficult to correct spherical aberration caused by on-axis light beams, which is also undesirable.

[0073] Conditional equation (21) is an equation that specifies the shape factor of the lens in the third lens group L3 that is positioned closest to the object.

[0074] If the upper limit of condition (21) is exceeded, the curvature of the object-side surface of the lens positioned closest to the object in the third lens group L3 becomes large, making it difficult to suppress field curvature caused by off-axis light beams at the wide-angle end, which is undesirable. If the lower limit of condition (21) is fallen below, the curvature of the object-side lens surface of the lens becomes small, making it difficult to correct spherical aberration caused by on-axis light beams, which is also undesirable. Furthermore, a small curvature results in a meniscus-shaped lens, making lens processing and shaping difficult, which is also undesirable.

[0075] Conditional equation (22) is an equation that specifies the shape factor of the lens positioned closest to the image in the third lens group L3.

[0076] If the upper limit of condition (22) is exceeded, the curvature of the object-side lens surface of the lens positioned closest to the image in the third lens group L3 becomes large, making it difficult to suppress chromatic aberration caused by off-axis light beams, which is undesirable. If the lower limit of condition (22) is exceeded, the curvature of the object-side lens surface of the lens becomes small, making it difficult to correct axial chromatic aberration caused by on-axis light beams, which is also undesirable.

[0077] Conditional equation (23) defines the ratio of the optical axis distance PL between the image-side surface of the prism P positioned on the object side of the first lens group L1 and the object-side lens surface of the lens positioned on the object side of the first lens group L1, and the total optical length.

[0078] If the upper limit of condition (23) is exceeded, the reflective surface of the prism P for bending the off-axis light beam will be too far from the first lens group L1, which is undesirable because it will increase the size of the prism P. If the lower limit of condition (23) is exceeded, it will be difficult to position the lens holding member and other components between the prism P and the first lens group L1, which is also undesirable.

[0079] Furthermore, it is more preferable to use the following conditional expressions (2a) to (23a) for the numerical ranges of conditional expressions (2) to (23). 1.30 <f1 / f3<4.80 (2a) 1.80 <ft / fw<2.40 (3a) -2.00 <f1 / fw<-1.30 (4a) -1.05 <f1 / ft<-0.55 (5a) -5.00 <f1 / f2<-1.50 (6a) -1.20 <f2 / f3<-0.40 (7a) 0.70 <ft / TL<1.20 (8a) 0.15 <MD2 / TL<0.30 (9a) 0.15 <MD3 / TL<0.35 (10a) 2.20 <Fnow<2.80 (11a) 3.50 <Fnot<5.00 (12a) 23.00 <TL×Fnot / imgH<33.50 (13a) 0.13 <skw / TL<0.22 (14a) 0.13 <skt / TL<0.45 (15a) 0.35 <HOVt / HOVw<0.60 (16a) 0.60 <LD11 / imgH<0.95 (17a) 0.95 <LD11 / LD3L<1.30 (18a) -11.00 <SF11<3.00 (19a) -1.00 <SF21<0.50 (20a) -3.00 <SF31<0.50 (21a) -90.00 <SF3L<20.00 (22a) 0.045 <PL / TL<0.065 (23a)

[0080] Furthermore, it is even more preferable to use the following conditional expressions (2b) to (23b) for the numerical ranges of conditional expressions (2) to (23). 1.40 <f1 / f3<4.50 (2b) 1.90 <ft / fw<2.30 (3b) -1.90 <f1 / fw<-1.40 (4b) -1.00 <f1 / ft<-0.60 (5b) -4.50 <f1 / f2<-2.00 (6b) -1.10 <f2 / f3<-0.50 (7b) 0.80 <ft / TL<1.10 (8b) 0.20 <MD2 / TL<0.25 (9b) 0.20 <MD3 / TL<0.30 (10b) 2.40 <Fnow<2.60 (11b) 3.80 <Fnot<4.50 (12b) 25.00 <TL×Fnot / imgH<32.00 (13b) 0.14 <skw / TL<0.21 (14b) 0.14 <skt / TL<0.44 (15b) 0.40 <HOVt / HOVw<0.55 (16b) 0.65 <LD11 / imgH<0.90 (17b) 1.00 <LD11 / LD3L<1.25 (18b) -10.00 <SF11<2.5 (19b) -0.10 <SF21<0.25 (20b) -2.00 <SF31<0.20 (21b) -80.00 <SF3L<10.00 (22b) 0.050 <PL / TL<0.060 (23b)

[0081] Next, we will describe the preferred configurations that the zoom lens L0 of each embodiment should satisfy.

[0082] In the zoom lens L0 of each embodiment, it is preferable to place the prism on the object side of the first lens group L1. By having the light beam bent by the prism enter the first lens group L1, the zoom lens L0 can be miniaturized. If it is not necessary to bend the light rays, the prism does not need to be placed.

[0083] In the zoom lens L0 of each embodiment, it is preferable that the first lens group L1 has two positive lenses in order from the object side to the image side. This makes it possible to shorten the focal length at the wide-angle end. Furthermore, it is more preferable to have a positive lens, a positive lens, and a negative lens in order from the object side to the image side, as this allows for the correction of aberrations such as spherical aberration and axial chromatic aberration at the telephoto end.

[0084] Furthermore, it is preferable that the lenses constituting the first lens group L1 are aspherical lenses. This makes it easier to effectively correct field curvature at the wide-angle end, correct spherical aberration at the telephoto end, and achieve miniaturization.

[0085] In the zoom lens L0 of each embodiment, the second lens group L2 preferably consists of two lenses, one with positive refractive power and the other with negative refractive power, in order from the object side to the image side. This converges the light beam diverged by the first lens group L1, making it possible to achieve both a long focal length at the telephoto end and miniaturization of the third lens group L3.

[0086] In the zoom lens L0 of each embodiment, lens groups such as the fourth lens group L4 and the fifth lens group L5 may be arranged on the image side of the third lens group L3. By arranging more lens groups, it becomes possible to more effectively correct the optical performance associated with high magnification.

[0087] In the zoom lens L0 of each embodiment, it is preferable to position the aperture diaphragm SP between the first lens group L1 and the second lens group L2. This allows the exit pupil to be positioned on the object side, enabling miniaturization of the first lens group L1. Furthermore, since more lenses can be positioned on the image side of the aperture diaphragm SP, it becomes easier to suppress field curvature and chromatic aberration variations caused by magnification changes, which are mainly caused by off-axis rays.

[0088] In the zoom lens L0 of each embodiment, it is preferable that the first lens group L1 includes an aspherical lens having an inflection point. An inflection point on the lens surface is a point where the sign of the refractive power of the lens changes from near the optical axis to the periphery of the lens surface. By including an aspherical lens with an inflection point, image field distortion and astigmatism can be corrected effectively.

[0089] As an example of an aspherical lens with an inflection point, the object-side lens surface of the aspherical lens is convex towards the object near the optical axis and concave towards the object at the periphery. Similarly, the image-side lens surface of the aspherical lens is concave towards the image near the optical axis and convex towards the image at the periphery. This allows for correction of Petzval sum near the optical axis while correcting astigmatism at the periphery. Furthermore, the object-side lens surface of the aspherical lens may be concave towards the object near the optical axis and convex towards the object at the periphery. Similarly, the image-side lens surface of the aspherical lens may be concave towards the image near the optical axis and convex towards the image at the periphery.

[0090] In the zoom lens L0 of each embodiment, vibration isolation can be achieved by moving any entire lens group or a part thereof as a vibration isolation group so as to include a component perpendicular to the optical axis, or by rotating it in a plane including the optical axis. In this case, it is preferable to move any entire lens group or a part thereof, which is positioned closer to the image than the first lens group L1, so as to include a component perpendicular to the optical axis, in order to perform vibration isolation.

[0091] In the zoom lens L0 of each embodiment, focusing can also be achieved by moving any entire lens group or a part thereof as a focusing group to include a component in the optical axis direction.

[0092] In each embodiment, it is preferable that the zoom lens L0 does not include a diffractive optical element. While providing a diffractive optical element in the optical system is advantageous from the viewpoint of chromatic aberration correction, it is undesirable because diffraction flare occurs in the diffractive optical element.

[0093] Next, we will describe the detailed configurations of Examples 1 to 5. Note that for the zoom lens L0 in each example, we will omit the explanation of configurations similar to the zoom lens L0 in Example 1, and will mainly describe the differences from Example 1.

[0094] [Example 1] Figure 2 is a cross-sectional view of the zoom lens L0 of Example 1 at its wide-angle and telephoto ends. Figure 3 is an aberration diagram of the zoom lens L0 of Example 1 at its (A) wide-angle and (B) telephoto ends, respectively. Example 1 is a zoom lens L0 with a magnification ratio of approximately 2.0 and an aperture ratio of approximately 1.6.

[0095] The zoom lens L0 of Example 1 consists of a prism P, a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, and a third lens group L3 with negative refractive power, arranged in order from the object side to the image side.

[0096] In the zoom lens L0 of Example 1, the first lens group L1 consists of G1 to G3 lenses, the second lens group L2 consists of G4 and G5 lenses, and the third lens group L3 consists of G6 and G7 lenses. Furthermore, the G1, G3, G4, G6, and G7 lenses are aspherical lenses made of resin material. The lens surfaces of the G3 and G7 lenses each have an inflection point.

[0097] In the zoom lens L0 of Example 1, under the reference state of object distance at infinity, when zooming from the wide-angle end to the telephoto end, the first lens group L1 remains stationary relative to the image plane, while the second lens group L2 and the third lens group L3 move toward the object. By keeping the first lens group L1 stationary relative to the image plane during zooming, the eccentricity of the first lens group L1 that occurs during zooming due to manufacturing errors, etc., is suppressed, and variations in aberrations due to eccentricity are reduced.

[0098] In the zoom lens L0 of Example 1, the G1 lens has a positive refractive power, the G2 lens has a positive refractive power, and the G3 lens has a negative refractive power.

[0099] In the zoom lens L0 of Example 1, the second lens group L2 consists of positive and negative lenses arranged in order from the object side to the image side. This allows the light beam diverged by the first lens group L1 to be focused by the second lens group L2, ensuring a long focal length at the telephoto end while miniaturizing the third lens group L3.

[0100] In the zoom lens L0 of Example 1, the aperture diaphragm SP is positioned between the first lens group L1 and the second lens group L2. This allows the exit pupil to be positioned on the object side, enabling miniaturization of the first lens group L1. Furthermore, since more lenses can be positioned on the image side of the aperture diaphragm SP, it is possible to suppress field curvature and variations in magnification chromatic aberration mainly caused by off-axis rays.

[0101] [Example 2] Figure 4 is a cross-sectional view of the zoom lens L0 of Example 2 at its wide-angle and telephoto ends. Figure 5 is an aberration diagram of the zoom lens L0 of Example 2 at (A) the wide-angle end and (B) the telephoto end, respectively. Example 2 is a zoom lens L0 with a zoom ratio of approximately 2.0 and an aperture ratio of approximately 1.6.

[0102] In the zoom lens L0 of Example 2, the first lens group L1 consists of G1 and G2 lenses, the second lens group L2 consists of G3 and G4 lenses, and the third lens group L3 consists of G5 and G6 lenses. Furthermore, the G2, G3, G5, and G6 lenses are aspherical lenses made of resin material. Each lens surface of the G1, G2, and G5 lenses has an inflection point.

[0103] [Examples 3 and 4] Figure 6 is a cross-sectional view of the zoom lens L0 of Example 3 at its wide-angle and telephoto ends. Figure 7 is an aberration diagram of the zoom lens L0 of Example 3 at (A) the wide-angle end and (B) the telephoto end, respectively. Example 3 is a zoom lens L0 with a zoom ratio of approximately 2.2 and an aperture ratio of approximately 1.6.

[0104] Figure 8 is a cross-sectional view of the zoom lens L0 of Embodiment 4 of the present invention at its wide-angle and telephoto ends. Figure 9 is an aberration diagram of the zoom lens L0 of Embodiment 4 at (A) the wide-angle end and (B) the telephoto end, respectively. Embodiment 4 is a zoom lens L0 with a zoom ratio of approximately 2.1 and an aperture ratio of approximately 1.7.

[0105] The zoom lens L0 in Examples 3 and 4 consists of a prism P, a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, arranged in order from the object side to the image side.

[0106] In the zoom lenses L0 of Examples 3 and 4, the first lens group L1 consists of G1 to G3 lenses, the second lens group L2 consists of G4 and G5 lenses, the third lens group L3 consists of G6 and G7 lenses, and the fourth lens L4 consists of G8 lens. Furthermore, the G1, G3, G4, G6, and G7 lenses are aspherical lenses made of resin material. Each lens surface of the G1, G3, G6, and G7 lenses has an inflection point.

[0107] In the zoom lens L0 of Examples 3 and 4, under the reference state where the object distance is infinity, when changing magnification from the wide-angle end to the telephoto end, the first lens group L1 and the fourth lens group L4 remain stationary relative to the image plane, while the second lens group L2 and the third lens group L3 move toward the object.

[0108] [Example 5] Figure 10 is a cross-sectional view of the zoom lens L0 of Embodiment 5 of the present invention at its wide-angle and telephoto ends. Figure 11 is an aberration diagram of the zoom lens L0 of Embodiment 5 at (A) the wide-angle end and (B) the telephoto end, respectively. Embodiment 5 is a zoom lens L0 with a zoom ratio of approximately 2.0 and an aperture ratio of approximately 1.6.

[0109] The zoom lens L0 of Example 5 consists of a prism P, a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with negative refractive power, arranged in order from the object side to the image side.

[0110] In the zoom lens L0 of Example 5, the first lens group L1 consists of G1 to G3 lenses, the second lens group L2 consists of G4 and G5 lenses, the third lens group L3 consists of G6 and G7 lenses, the fourth lens L4 consists of G8 lens, and the fifth lens group L5 consists of G9 lens. Furthermore, the G1, G3, G4, G6, G7, and G9 lenses are aspherical lenses made of resin material.

[0111] In the zoom lens L0 of Example 5, under the reference state where the object distance is infinity, when changing magnification from the wide-angle end to the telephoto end, the first lens group L1 and the fifth lens group L5 remain stationary relative to the image plane, while the second lens group L2, the third lens L3, and the fourth lens group L4 each move toward the object so that the spacing between adjacent lens groups changes.

[0112] The following shows the numerical values ​​corresponding to the zoom lens L0 of Examples 1 to 5.

[0113] In the surface data for each numerical example, r(mm) represents the radius of curvature of each optical surface, and d(mm) represents the distance on the optical axis between the k-th surface and the (k+1)-th surface. Here, k is the surface number counted from the object side. Also, nd represents the refractive index of the material of each optical component with respect to the d line, and νd represents the Abbe number of the material of each optical component. Here, the Abbe number νd is given by the refractive index of the Fraunhofer lines c-line (656.3 nm), d-line (587.56 nm), and F-line (486.1 nm), respectively, where nC, nd, and nF are the refractive indices. νd=(nd-1) / (nF-nC) It is represented as follows.

[0114] In each numerical example, the half-angle of view (°) of the optical system L0 is shown, and the maximum image height corresponding to that half-angle of view is shown as "image height". Furthermore, in each numerical example, the focal length of each lens group at the d line is shown as lens group data. Note that d, focal length (mm), F number, and half-angle of view (°) are the values ​​when the optical system L0 of each example is focused at infinity. BF (back focus) represents the distance along the optical axis from the final lens surface (the surface closest to the image) to the paraxial image plane, converted to air equivalent. The total lens length is the sum of the distance along the optical axis from the object-side lens surface of the lens placed closest to the object among the lenses included in the optical system L0 to the image-side lens surface of the lens placed closest to the image, and the back focus.

[0115] Furthermore, for each lens, if the lens surface is aspherical, the sign * is added to the right of the surface number. The aspherical shape is expressed by the following formula, where X is the displacement from the surface vertex in the optical axis direction, h is the height from the optical axis perpendicular to the optical axis, R is the radius of paraxial curvature, k is the cone constant, and A4, A6, A8, A10, A12, A14, and A16 are the aspherical coefficients of their respective orders. X=(h2 / R) / [1+{1-(1+k)(h / R)2}1 / 2]+A4×h4+A6×h6+A8×h8+A10×h10+A12×h12+A14×h14+A16×h16

[0116] For each aspherical coefficient, "e±XX" means "×10±XX".

[0117] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd Effective diameter 1 ∞ 2.40 1.71700 29.5 7.43 2 ∞ 2.40 1.71700 29.5 6.57 3 ∞ (variable) 5.71 4* 13.422 1.05 1.54400 56.0 5.06 5* -7.499 0.10 5.00 6* -16.595 1.26 1.67100 19.4 4.88 7* -8.762 0.10 4.68 8* 11.940 0.40 1.54400 56.0 4.60 9* 1.952 (variable) 4.50 10 (aperture) ∞ -0.31 4.85 11* 4.134 2.50 1.54400 56.0 4.97 12* -3.187 0.08 4.81 13* -3.405 2.00 1.67100 19.4 4.76 14* -5.632 (variable) 4.80 15* -8.614 2.21 1.54400 56.0 4.49 16* 8.763 1.24 4.37 17* 8.685 0.50 1.53110 55.9 4.53 18* 6.680 (Variable) 4.88 Image plane ∞ Aspherical data Side 4 K =-5.00000e+01 A 4= 6.45679e-03 A 6=-1.16102e-03 A 8= 2.18287e-04 A10=-4.02094e-05 A12= 5.46786e-06 A14=-3.58895e-07 Page 5 K =-5.08534e+01 A 4= 1.08521e-02 A 6=-4.87577e-03 A 8= 6.58589e-04 A10= 5.93687e-05 A12=-2.33811e-05 A14= 1.51970e-06 Page 6 K =-9.48145e+00 A 4= 1.05753e-02 A 6=-4.62981e-03 A 8= 4.96157e-04 A10= 1.38482e-04 A12=-3.85259e-05 A14= 2.53746e-06 Page 7 K =-4.72191e+01 A 4= 7.38711e-03 A 6=-6.57375e-03 A 8= 1.76459e-03 A10=-1.86570e-04 A12=-1.48471e-07 A14= 8.08853e-07 Page 8 K =-5.00000e+01 A 4=-2.49546e-02 A 6=-6.44448e-04 A 8= 1.46722e-03 A10=-3.12811e-04 A12= 2.59455e-05 A14=-7.10552e-07 Page 9 K =-3.23281e+00 A 4=-2.93176e-02 A 6= 9.49505e-03 A 8=-1.95840e-03 A10= 2.52087e-04 A12=-1.76853e-05 A14= 5.07998e-07 Page 11 K = 8.63012e-01 A 4=-1.98280e-03 A 6=-3.18847e-04 A 8= 1.00730e-04 A10=-3.24980e-05 A12= 4.37044e-06 A14=-2.46703e-07 Page 12 K =-2.16519e+00 A 4= 8.78145e-03 A 6=-2.76510e-03 A 8= 7.67430e-04 A10=-1.32057e-04 A12= 1.33261e-05 A14=-5.82661e-07 Page 13 K =-6.65165e+00 A 4=-6.61555e-03 A 6= 1.01882e-03 A 8=-6.86452e-05 A10= 4.46382e-06 A12=-6.62627e-07 A14= 1.31549e-07 A16=-1.20755e-08 Page 14 K =-1.42286e+01 A 4=-3.01368e-03 A 6= 8.95654e-04 A 8=-1.93368e-04 A10= 3.76241e-05 A12=-4.90321e-06 A14= 3.33301e-07 A16=-4.88393e-09 Page 15 K =-1.85471e+00 A 4= 6.37349e-03 A 6=-1.45487e-03 A 8= 3.51614e-04 A10=-9.02821e-05 A12= 1.52255e-05 A14=-1.65158e-06 A16= 1.05077e-07 Page 16 K =-5.00000e+01 A 4=-1.07975e-03 A 6= 2.02774e-04 A 8= 1.82165e-04 A10=-1.28967e-04 A12= 3.84059e-05 A14=-6.90048e-06 A16= 6.81804e-07 Page 17 K =-8.18574e+00 A 4=-5.38803e-02 A 6= 3.50951e-03 A 8= 1.69084e-03 A10=-5.61345e-04 A12=-2.54279e-05 A14= 2.86424e-05 A16=-2.60802e-06 Side 18 K = 4.80230e+00 A 4=-5.12492e-02 A 6= 5.91592e-03 A 8= 5.61131e-04 A10=-5.01211e-04 A12= 9.07719e-05 A14=-5.46291e-06 A16= 2.50860e-08 Various data Zoom ratio 1.97 Wide-angle end Telephoto end Focal length 10.26 20.24 F-number 2.43 4.00 Half-angle 17.33 8.99 Image height 3.20 3.20 Lens length 26.99 26.99 BF 3.37 8.51 d 3 1.25 1.25 d 9 5.43 0.81 d14 1.02 0.50 d18 3.37 8.51 Zoom lens group data Group starting plane focal length L1 4 -18.74 L2 10 5.27 L3 15 -6.44

[0118] [Numerical Example 2] Unit: mm Surface data Face number rd nd νd Effective diameter 1 ∞ 2.40 1.53340 55.9 6.29 2 ∞ 2.40 1.53340 55.9 5.32 3 ∞ (variable) 5.09 4* -36.104 0.63 1.67100 19.4 5.09 5* -14.075 0.10 4.97 6* 3.477 0.50 1.54400 56.0 4.95 7* 2.161 (variable) 4.99 8 (aperture) ∞ -0.23 5.33 9* 4.854 2.67 1.53110 55.9 5.46 10* -3.042 0.08 5.33 11* -3.018 2.00 1.67100 19.4 5.29 12* -4.849 (variable) 5.38 13* -18.993 1.81 1.53110 55.9 5.11 14* 14.875 1.52 4.95 15* -8.595 1.56 1.54400 56.0 4.38 16* 34.025 (Variable) 5.06 Image plane ∞ Aspherical data Side 4 K =-4.99895e+01 A 4= 1.19638e-02 A 6=-3.71411e-03 A 8= 1.05986e-03 A10=-1.82235e-04 A12= 1.73568e-05 A14=-6.79253e-07 5th page K =-2.88784e+01 A 4= 1.17930e-02 A 6=-5.49272e-03 A 8= 2.02058e-03 A10=-3.97381e-04 A12= 4.00922e-05 A14=-1.59737e-06 Page 6 K = 4.85132e-01 A 4=-4.84156e-02 A 6= 3.84854e-03 A 8= 1.10944e-03 A10=-4.31811e-04 A12= 5.41742e-05 A14=-2.54972e-06 Page 7 K =-2.89730e+00 A 4=-3.28694e-02 A 6= 7.59573e-03 A 8=-9.03799e-04 A10= 2.35523e-05 A12= 5.21754e-06 A14=-3.74025e-07 Page 9 K = 9.19476e-01 A 4=-1.05162e-03 A 6=-3.47130e-04 A 8= 8.97635e-05 A10=-1.95003e-05 A12= 1.81030e-06 A14=-6.95774e-08 Page 10 K =-1.05177e+01 A 4=-2.67912e-02 A 6= 8.27490e-03 A 8=-1.27026e-03 A10= 9.19955e-05 A12=-1.92072e-06 A14=-4.49002e-08 Page 11 K =-9.85560e+00 A 4=-2.74927e-02 A 6= 8.25163e-03 A 8=-1.16435e-03 A10= 5.80313e-05 A12= 4.31003e-06 A14=-6.25392e-07 A16= 2.11104e-08 Page 12 K =-2.57934e+00 A 4= 2.24486e-03 A 6=-3.89127e-04 A 8= 2.17263e-04 A10=-4.40455e-05 A12= 4.95075e-06 A14=-3.12117e-07 A16= 9.38660e-09 Page 13 K =-4.99883e+01 A 4=-2.56468e-04 A 6=-5.29857e-04 A 8= 1.25362e-04 A10= 1.53768e-05 A12=-9.45397e-06 A14= 1.36178e-06 A16=-6.48844e-08 Page 14 K =-5.00000e+01 A 4=-1.06646e-02 A 6=-6.39275e-04 A 8= 3.21417e-04 A10=-6.54862e-05 A12= 8.52574e-06 A14=-4.54975e-07 A16=-2.02868e-11 Page 15 K = 3.24312e+00 A 4=-1.80892e-02 A 6=-3.99267e-03 A 8= 2.99970e-03 A10=-1.25057e-03 A12= 3.06264e-04 A14=-3.76162e-05 A16= 1.78677e-06 Page 16 K = 5.00000e+01 A 4=-8.58187e-03 A 6=-7.65024e-04 A 8= 9.48955e-04 A10=-3.16805e-04 A12= 5.71957e-05 A14=-5.26736e-06 A16= 1.92688e-07 Various data Zoom ratio 1.99 Wide-angle end Telephoto end Focal length 10.25 20.37 F-number 2.43 4.00 Half-angle 17.34 8.93 Image height 3.20 3.20 Lens length 27.05 27.05 BF 3.49 9.14 d 3 1.25 1.25 d 7 5.79 0.72 d12 1.09 0.50 d16 3.49 9.14 Zoom lens group data Group starting plane focal length L1 4 -19.60 L2 8 5.82 L3 13 -6.38

[0119] [Numerical Example 3] Unit: mm Surface data Face number rd nd νd Effective diameter 1 ∞ 2.40 1.71700 29.5 7.42 2 ∞ 2.40 1.71700 29.5 6.34 3 ∞ (variable) 5.27 4* -8.182 0.47 1.54400 56.0 4.44 5* -10.343 0.16 4.43 6* -81.705 0.87 1.67100 19.4 4.42 7* -13.920 0.13 4.42 8* 9.213 0.55 1.54400 56.0 4.41 9* 3.142 (variable) 4.60 10 (aperture) ∞ -0.51 5.01 11* 3.614 2.64 1.54400 56.0 5.20 12* -3.049 0.08 5.04 13* -3.306 1.39 1.65100 21.5 4.96 14* -7.174 (variable) 4.45 15* -7.461 0.82 1.53110 55.9 4.50 16* -165.448 0.77 4.41 17* 4.329 0.57 1.54400 56.0 4.07 18* 2.866 (variable) 4.39 19* -6.587 0.92 1.68100 18.1 5.28 20* -5.783 (variable) 5.58 Image plane ∞ Aspherical data Side 4 K =-2.91778e+01 A 4= 8.94780e-03 A 6=-1.49623e-03 A 8= 3.37729e-04 A10=-4.24950e-05 A12= 6.50851e-07 A14= 1.77120e-07 5th page K =-3.67398e+00 A 4= 1.63182e-02 A 6=-3.62487e-03 A 8= 7.12025e-04 A10=-7.25494e-05 A12=-3.02057e-06 A14= 7.44186e-07 Page 6 K =-1.24055e+01 A 4= 5.98067e-03 A 6=-1.95205e-03 A 8= 2.83289e-04 A10=-2.35439e-05 A12=-3.57306e-07 A14= 1.99547e-07 Side 7 K =-1.19082e+01 A 4= 4.50144e-03 A 6=-1.79196e-03 A 8= 2.74779e-04 A10=-6.14895e-05 A12= 1.26859e-05 A14=-1.03754e-06 Side 8 K =-4.85569e+01 A 4=-3.68409e-02 A 6= 7.24505e-03 A 8=-1.10310e-03 A10= 8.33933e-05 A12= 2.19402e-06 A14=-6.60356e-07 9th page K =-7.90054e+00 A 4=-2.53300e-02 A 6= 6.69641e-03 A 8=-1.21377e-03 A10= 1.48881e-04 A12=-1.08664e-05 A14= 3.59802e-07 Page 11 K = 5.03507e-02 A 4=-6.32634e-04 A 6=-1.51802e-04 A 8= 4.04476e-05 A10=-1.10689e-05 A12= 1.32663e-06 A14=-1.00187e-07 Page 12 K =-1.63758e+00 A 4= 1.06150e-02 A 6=-1.23691e-05 A 8= 1.34442e-04 A10=-3.38532e-05 A12= 1.58283e-07 A14= 1.57392e-07 Page 13 K =-1.07718e+00 A 4= 3.22772e-03 A 6= 2.59553e-03 A 8= 3.10670e-05 A10=-1.42458e-04 A12= 3.06453e-05 A14=-3.16991e-06 A16= 1.37181e-07 Page 14 K =-1.35814e+01 A 4=-2.20006e-03 A 6= 3.65569e-03 A 8=-4.69467e-04 A10= 6.91819e-05 A12=-9.18123e-06 A14= 2.52947e-06 A16=-3.17042e-07 Page 15 K =-3.73694e+01 A 4= 1.78201e-02 A 6=-1.13257e-03 A 8=-2.69236e-05 A10= 3.67488e-05 A12= 1.54726e-05 A14=-4.52877e-06 A16= 1.79803e-07 Page 16 K =-6.82689e+00 A 4= 4.42700e-03 A 6= 3.52616e-04 A 8=-6.30919e-04 A10=-2.30033e-04 A12= 2.10063e-04 A14=-4.81014e-05 A16= 3.52390e-06 Page 17 K =-2.04580e+01 A 4=-4.38567e-02 A 6= 5.56492e-04 A 8= 3.14719e-03 A10=-2.28902e-03 A12= 8.13838e-04 A14=-1.47458e-04 A16= 1.06745e-05 Side 18 K =-1.03932e+00 A 4=-6.58199e-02 A 6= 1.95415e-02 A 8=-6.46549e-03 A10= 1.86883e-03 A12=-3.68161e-04 A14= 4.23520e-05 A16=-2.12215e-06 Page 19 K =-1.17128e+00 A 4= 4.01418e-03 A 6=-3.51171e-05 A 8=-2.17475e-05 A10= 6.83404e-07 A12=-2.54535e-08 Page 20 K = 5.13974e-01 A 4= 3.98428e-03 A 6= 6.60626e-05 A 8=-2.17634e-05 A10= 7.62470e-07 A12=-2.26608e-08 Various data Zoom ratio 2.20 Wide-angle end Telephoto end Focal length 8.06 17.77 F-number 2.43 4.00 Half-angle 21.65 10.21 Image height 3.20 3.20 Lens length 26.99 26.99 BF 4.33 4.33 d 3 1.25 1.25 d 9 6.16 1.01 d14 0.50 0.59 d18 1.08 6.13 d20 4.33 4.33 Zoom lens group data Group starting plane focal length L1 4 -12.00 L2 10 5.11 L3 15 -7.52 L4 19 47.48

[0120] [Numerical Example 4] Unit: mm Surface data Face number rd nd νd Effective diameter 1 ∞ 2.40 1.71700 29.5 7.40 2 ∞ 2.40 1.71700 29.5 6.63 3 ∞ (variable) 5.85 4* 7.240 1.14 1.54400 56.0 5.45 5* -25.012 0.11 5.27 6* -109.362 0.82 1.67100 19.4 5.14 7* -23.744 0.33 4.90 8* 10.113 0.40 1.54400 56.0 4.81 9* 2.090 (variable) 4.64 10 (aperture) ∞ -0.46 5.11 11* 3.812 2.60 1.49700 81.5 5.23 12* -3.871 0.08 5.04 13* -6.768 2.00 1.67100 19.4 4.87 14* -7.556 (variable) 4.68 15* -5.414 0.80 1.53110 55.9 4.29 16* 15.473 1.29 4.10 17* 25.226 0.50 1.54400 56.0 4.20 18* 6.044 (variable) 4.49 19* -12.496 1.22 1.56700 38.0 5.50 20* -7.136 (variable) 5.91 Image plane ∞ Aspherical data Side 4 K =-1.33774e+01 A 4= 6.53398e-03 A 6=-1.22627e-03 A 8= 2.54391e-04 A10=-3.69418e-05 A12= 3.19170e-06 A14=-1.07792e-07 5th page K =-5.34359e+02 A 4= 1.20361e-02 A 6=-5.55145e-03 A 8= 1.09991e-03 A10=-1.04501e-04 A12= 3.89772e-06 A14=-5.98149e-09 Page 6 K = 4.99960e+01 A 4= 1.28672e-02 A 6=-4.06632e-03 A 8= 2.50721e-04 A10= 1.08468e-04 A12=-2.13526e-05 A14= 1.11293e-06 Side 7 K = 7.71717e+00 A 4= 1.49464e-02 A 6=-5.15666e-03 A 8= 3.71943e-04 A10= 1.47525e-04 A12=-3.22377e-05 A14= 1.83041e-06 Side 8 K =-5.00000e+01 A 4=-2.63609e-02 A 6= 1.00502e-03 A 8= 6.97554e-04 A10=-1.23881e-04 A12= 5.77558e-06 A14= 4.40681e-08 Page 9 K =-2.80067e+00 A 4=-3.28764e-02 A 6= 9.79311e-03 A 8=-1.58270e-03 A10= 1.45980e-04 A12=-6.61810e-06 A14= 8.17964e-08 Page 11 K = 3.97222e-01 A 4=-2.13330e-03 A 6=-4.80760e-05 A 8= 5.27041e-06 A10=-5.61443e-06 A12= 8.87337e-07 A14=-7.37008e-08 Page 12 K =-1.58152e+00 A 4= 1.22773e-02 A 6=-3.45919e-03 A 8= 7.98886e-04 A10=-1.05882e-04 A12= 6.83670e-06 A14=-1.60520e-07 Page 13 K =-4.51421e+00 A 4= 6.52327e-03 A 6=-2.99333e-03 A 8= 5.40251e-04 A10=-1.35430e-05 A12=-1.13411e-05 A14= 1.72482e-06 A16=-7.73859e-08 Page 14 K =-3.85569e+00 A 4= 1.03711e-02 A 6=-3.80301e-03 A 8= 8.06985e-04 A10=-8.62803e-05 A12=-2.07853e-06 A14= 1.35510e-06 A16=-8.81206e-08 Page 15 K =-1.90890e+01 A 4= 1.48613e-02 A 6=-2.41812e-03 A 8= 9.72581e-04 A10=-3.87948e-04 A12= 8.54333e-05 A14=-1.23428e-05 A16= 7.36637e-07 Page 16 K =-2.34847e+01 A 4=-2.38623e-03 A 6= 7.60779e-03 A 8=-1.28126e-03 A10=-2.42572e-04 A12= 2.33222e-04 A14=-6.11953e-05 A16= 5.19704e-06 Page 17 K = 8.71923e+00 A 4=-8.21595e-02 A 6= 2.78008e-02 A 8=-5.27161e-03 A10= 2.99002e-04 A12= 1.34236e-04 A14=-3.10348e-05 A16= 1.90586e-06 Page 18 K =-2.67798e+01 A 4=-5.47926e-02 A 6= 2.42748e-02 A 8=-7.74179e-03 A10= 1.88215e-03 A12=-3.18062e-04 A14= 3.31317e-05 A16=-1.58421e-06 Page 19 K = 1.67875e+01 A 4=-1.25306e-03 A 6=-2.76878e-04 A 8= 1.18557e-04 A10=-6.86074e-06 A12=-7.65998e-07 A14= 1.01358e-07 Page 20 K = 3.81201e+00 A 4=-1.34682e-03 A 6= 8.77461e-05 A 8= 7.34437e-06 A10= 7.10758e-06 A12=-1.21921e-06 A14= 7.03805e-08 Various data Zoom ratio 2.09 Wide-angle end Telephoto end Focal length 11.50 24.00 F-number 2.55 4.40 Half-angle 15.55 7.60 Image height 3.20 3.20 Lens length 28.05 28.05 BF 3.50 3.50 d 3 1.25 1.25 d 9 6.27 0.96 d14 0.61 0.50 d18 0.80 6.21 d20 3.50 3.50 Zoom lens group data Group starting plane focal length L1 4 -20.00 L2 10 4.87 L3 15 -4.52 L4 19 27.12

[0121] [Numerical Example 5] Unit: mm Surface data Face number rd nd νd Effective diameter 1 ∞ 2.40 1.71700 29.5 7.40 2 ∞ 2.40 1.71700 29.5 6.54 3 ∞ (variable) 5.67 4* 58.969 1.16 1.54400 56.0 5.20 5* -6.190 0.16 4.95 6* -9126.338 0.84 1.68100 18.1 4.87 7* -26.415 0.11 4.80 8* 10.788 0.49 1.54400 56.0 4.77 9* 2.000 (variable) 4.76 10 (aperture) ∞ -0.37 5.40 11* 4.106 3.46 1.54400 56.0 5.59 12* -3.079 0.08 5.16 13* -2.880 1.55 1.65100 21.5 5.11 14* -5.297 (variable) 4.79 15* -10.498 1.79 1.54400 56.0 5.04 16* 9.738 0.56 4.68 17* 3.666 0.50 1.53110 55.9 4.70 18* 3.770 (variable) 4.94 19* 20.641 1.10 1.67100 19.4 5.16 20* 34.074 (Variable) 5.10 21* -9.884 0.96 1.54400 56.0 5.27 22* -12.047 (variable) 5.61 Image plane ∞ Aspherical data Side 4 K = 1.60780e+02 A 4= 7.15059e-03 A 6=-7.32627e-04 A 8= 1.06621e-04 A10=-2.91538e-06 A12=-7.18025e-07 A14= 7.26937e-08 5th page K =-2.53909e+01 A 4= 1.43403e-02 A 6=-4.28845e-03 A 8= 8.76556e-04 A10=-9.99220e-05 A12= 5.84879e-06 A14=-1.24361e-07 Page 6 K =-5.00000e+01 A 4= 4.98077e-03 A 6=-2.41076e-03 A 8= 7.12172e-05 A10= 7.70043e-05 A12=-1.32593e-05 A14= 6.67605e-07 Page 7 K =-6.34515e+00 A 4= 4.21810e-03 A 6=-2.49743e-03 A 8=-2.96743e-05 A10= 1.38845e-04 A12=-2.39780e-05 A14= 1.27474e-06 Page 8 K =-2.77476e+01 A 4=-2.63224e-02 A 6= 3.62400e-03 A 8=-5.34442e-04 A10= 9.75066e-05 A12=-1.32147e-05 A14= 7.00342e-07 Page 9 K =-3.59670e+00 A 4=-2.22828e-02 A 6= 6.45526e-03 A 8=-1.21411e-03 A10= 1.41562e-04 A12=-9.26228e-06 A14= 2.63159e-07 Page 11 K =-4.54498e-01 A 4=-5.66826e-05 A 6=-3.35579e-05 A 8= 2.47052e-05 A10=-5.14797e-06 A12= 4.90263e-07 A14=-1.93944e-08 Page 12 K =-2.15732e+00 A 4= 9.71327e-03 A 6=-1.85190e-03 A 8= 6.87839e-04 A10=-1.23851e-04 A12= 9.83569e-06 A14=-2.94912e-07 Page 13 K =-3.85644e+00 A 4= 1.92840e-03 A 6= 7.97940e-05 A 8= 3.81896e-04 A10=-8.79922e-05 A12= 7.30552e-06 A14=-2.17505e-07 A16= 2.02197e-10 Page 14 K =-1.22409e+01 A 4= 1.69136e-03 A 6= 1.74422e-03 A 8=-4.36989e-04 A10= 1.36753e-04 A12=-1.93036e-05 A14= 1.34743e-06 A16=-4.61776e-08 Page 15 K = 1.29447e+01 A 4= 5.78937e-03 A 6= 2.55002e-03 A 8=-1.06338e-03 A10= 3.67042e-04 A12=-6.23094e-05 A14= 5.15146e-06 A16=-1.67749e-07 Page 16 K =-2.30774e+01 A 4=-3.22174e-02 A 6= 1.52108e-02 A 8=-5.48208e-03 A10= 1.47836e-03 A12=-2.62504e-04 A14= 2.89748e-05 A16=-1.46572e-06 Page 17 K =-1.00921e+01 A 4=-4.93490e-02 A 6= 5.51742e-03 A 8= 1.47806e-03 A10=-1.15470e-03 A12= 3.09248e-04 A14=-3.65384e-05 A16= 1.58589e-06 Page 18 K = 8.61463e-04 A 4=-5.15586e-02 A 6= 7.98846e-03 A 8=-4.71954e-04 A10=-2.78959e-04 A12= 9.48032e-05 A14=-1.17956e-05 A16= 5.28423e-07 Page 19 K =-5.00000e+01 A 4= 1.27014e-03 A 6= 4.20218e-04 A 8=-2.64899e-05 A10= 7.22494e-07 A12=-2.31248e-07 A14= 1.00673e-08 Page 20 K =-5.00000e+01 A 4= 5.49598e-05 A 6= 4.50586e-04 A 8=-6.61358e-06 A10= 2.15575e-07 A12=-5.77095e-07 A14= 2.32139e-08 Page 21 K = 9.85050e+00 A 4=-1.75353e-03 A 6= 4.55529e-04 A 8= 1.45292e-05 A10=-6.57578e-06 A12= 3.30016e-07 A14= 2.25865e-08 Page 22 K =-7.38914e+00 A 4=-2.84411e-03 A 6= 3.43728e-04 A 8=-1.10704e-05 A10=-2.52120e-06 A12= 1.67633e-07 A14= 1.53265e-09 Various data Zoom ratio 2.04 Wide-angle end Telephoto end Focal length 10.21 20.80 F-number 2.43 4.00 Half-angle 17.40 8.75 Image height 3.20 3.20 Lens length 30.05 30.05 BF 3.50 3.50 d 3 1.25 1.25 d 9 6.09 0.87 d14 0.53 0.50 d18 0.50 3.74 d20 1.00 3.00 d22 3.50 3.50 Zoom lens group data Group starting surface Focal length L1 4 -14.68 L2 10 5.73 L3 15 -9.60 L4 19 75.55 L5 21 -120.00

[0122] The values corresponding to the conditional expressions (1) to (22) in each numerical example are shown in Tables 1 and 2 below.

[0123] [Table 1]

[0124] [Table 2]

[0125] [Imaging device] Next, an example of a smartphone using the zoom lens L0 of each example as an imaging optical system will be described.

[0126] In FIG. 12, 10 is a smartphone body, and 12 is an imaging optical system constituted by any one of the zoom lenses L0 described in Examples 1 to 5. The smartphone body 10 may have a plurality of zoom lenses L0, and may also have other zoom lenses.

[0127] The smartphone body 10 may also be a digital still camera or an in-car camera. In this case, the camera body contains a solid-state image sensor such as a CCD sensor or CMOS sensor that receives the optical image formed by the zoom lens 12 and converts it into photoelectric energy.

[0128] By applying the zoom lens L0 of this embodiment to an imaging device such as a smartphone, it is possible to obtain an imaging device that is compact yet capable of high-magnification zoom.

[0129] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist.

[0130] Furthermore, the disclosure of this embodiment includes the following configuration.

[0131] (Composition 1) A zoom lens comprising a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, arranged in order from the object side to the image side, wherein the distance between adjacent lenses changes when the magnification is changed. Each of the first to third lens groups has one or more aspherical lenses made of resin material. During the change in magnification from the wide-angle end to the telephoto end, the first lens group remains stationary with respect to the image plane. When TL is the distance along the optical axis from the object-side lens surface to the image plane of the lens positioned closest to the object in the first lens group, imgH is the maximum image height, f1 is the focal length of the first lens group, and f3 is the focal length of the third lens group, 0.11 <imgH / TL<0.20 1.20 <f1 / f3<5.00 A zoom lens characterized by satisfying the following conditional equation.

[0132] (Configuration 2) A zoom lens comprising a prism having a reflective surface arranged in order from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, wherein the distance between adjacent lenses changes when the magnification is changed. During the change in magnification from the wide-angle end to the telephoto end, the first lens group remains stationary with respect to the image plane. When TL is the distance along the optical axis from the object-side lens surface to the image plane of the lens positioned closest to the object in the first lens group, and imgH is the maximum image height, 0.11 <imgH / TL<0.20 A zoom lens characterized by satisfying the following conditional equation.

[0133] (Composition 3) When the F-number at the telephoto end is denoted as Fnot, 3.00 <Fnot<5.70 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditional expression.

[0134] (Composition 4) When the F-number at the wide-angle end is denoted as Fnow, 2.00 <Fnow<3.00 A zoom lens according to any one of configurations 1 to 3, characterized in that it satisfies the following conditional expression.

[0135] (Composition 5) The first lens group includes a prism having a reflective surface, which is positioned closest to the object. When PL is the distance along the optical axis between the image-side surface of the prism and the object-side lens surface of the lens positioned closest to the object in the first lens group, 0.04 <PL / TL<0.07 A zoom lens according to any one of configurations 1 to 4, characterized in that it satisfies the following conditional expression.

[0136] (Composition 6) When the total focal length of the zoom lens at the wide-angle end is fw and the total focal length of the zoom lens at the telephoto end is ft, 1.70 <ft / fw<2.50 A zoom lens according to any one of configurations 1 to 5, characterized in that it satisfies the following conditional expression.

[0137] (Composition 7) When the total focal length of the zoom lens at its wide-angle end is denoted as fw, -2.10 <f1 / fw<-1.20 A zoom lens according to any one of configurations 1 to 6, characterized by satisfying the following conditional expression.

[0138] (Composition 8) When the total focal length of the zoom lens at its telephoto end is denoted as ft, -1.10 <f1 / ft<-0.50 A zoom lens according to any one of configurations 1 to 7, characterized by satisfying the following conditional expression.

[0139] (Composition 9) When the focal length of the second lens group is f2, -6.00 <f1 / f2<-1.00 A zoom lens according to any one of configurations 1 to 8, characterized by satisfying the following conditional expression.

[0140] (Composition 10) When the focal length of the second lens group is f2, -1.30 <f2 / f3<-0.30 A zoom lens according to any one of configurations 1 to 9, characterized by satisfying the following conditional expression.

[0141] (Composition 11) When the total focal length of the zoom lens at its telephoto end is denoted as ft, 0.60 <ft / TL<1.30 A zoom lens according to any one of configurations 1 to 10, characterized by satisfying the following conditional expression.

[0142] (Composition 12) When the amount of movement of the second lens group during the change in magnification from the wide-angle end to the telephoto end is denoted as MD2, 0.10 <MD2 / TL<0.35 A zoom lens according to any one of configurations 1 to 11, characterized by satisfying the following conditional expression.

[0143] (Composition 13) When the amount of movement of the third lens group during the change in magnification from the wide-angle end to the telephoto end is denoted as MD3, 0.10 <MD3 / TL<0.40 A zoom lens according to any one of configurations 1 to 12, characterized by satisfying the following conditional expression.

[0144] (Composition 14) When the F-number at the telephoto end is denoted as Fnot, 20.00 <TL×Fnot / imgH<35.00 A zoom lens according to any one of configurations 1 to 13, characterized by satisfying the following conditional expression.

[0145] (Composition 15) When the back focus at the wide-angle end is denoted as skw, 0.12 <skw / TL<0.23 A zoom lens according to any one of configurations 1 to 14, characterized by satisfying the following conditional expression.

[0146] (Composition 16) When the back focus at the telephoto end is denoted as skt, 0.12 <skt / TL<0.46 A zoom lens according to any one of configurations 1 to 15, characterized by satisfying the following conditional expression.

[0147] (Composition 17) When the half-angle at the wide-angle end is HOVw and the half-angle at the telephoto end is HOVt, 0.30 <HOVt / HOVw<0.65 A zoom lens according to any one of configurations 1 to 16, characterized by satisfying the following conditional expression.

[0148] (Composition 18) When LD11 is half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group, 0.55 <LD11 / imgH<1.00 A zoom lens according to any one of configurations 1 to 17, characterized by satisfying the following conditional expression.

[0149] (Composition 19) When LD11 is half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group, and LD3L is half the effective diameter of the image-side lens surface of the lens positioned closest to the image in the third lens group, 0.90 <LD11 / LD3L<1.40 A zoom lens according to any one of configurations 1 to 18, characterized by satisfying the following conditional expression.

[0150] (Composition 20) When the shape factor of the lens positioned closest to the object in the first lens group is SF11, -12.00 <SF11<4.00 A zoom lens according to any one of configurations 1 to 19, characterized by satisfying the following conditional expression.

[0151] (Composition 21) When the shape factor of the lens positioned closest to the object in the second lens group is SF21, -2.00 <SF21<1.00 A zoom lens according to any one of configurations 1 to 20, characterized by satisfying the following conditional expression.

[0152] (Composition 22) When the shape factor of the lens positioned closest to the object in the third lens group is SF31, -5.00 <SF31<1.00 A zoom lens according to any one of configurations 1 to 21, characterized by satisfying the following conditional expression.

[0153] (Composition 23) When the shape factor of the lens positioned closest to the image in the third lens group is SF3L, -100.00 <SF3L<50.00 A zoom lens according to any one of configurations 1 to 22, characterized by satisfying the following conditional expression.

[0154] (Composition 24) The zoom lens according to any one of configurations 1 to 23, characterized in that the first lens group includes an aspherical lens having an inflection point.

[0155] (Composition 25) A zoom lens according to any one of configurations 1 to 24, comprising a prism having a reflective surface arranged in order from the object side to the image side, the first to third lens groups, and a fourth lens group with positive refractive power, characterized in that the distance between each lens changes when the zoom is changed from the wide-angle end to the telephoto end.

[0156] (Composition 26) A zoom lens according to any one of configurations 1 to 24, comprising a prism having a reflective surface arranged in order from the object side to the image side, the first to third lens groups, a fourth lens group with positive refractive power, and a fifth lens group with negative refractive power, characterized in that the distance between each lens changes when the magnification changes from the wide-angle end to the telephoto end.

[0157] (Composition 27) An imaging device characterized by comprising a zoom lens according to any one of configurations 1 to 26, and an image sensor that receives an image formed by the zoom lens. [Explanation of Symbols]

[0158] P Prism L0 Zoom Lens L1 First lens group L2 Second lens group L3 Third lens group SP aperture diaphragm IP image plane

Claims

1. A zoom lens comprising a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, arranged in order from the object side to the image side, wherein the spacing between adjacent lens groups changes during magnification, Each of the first to third lens groups has one or more aspherical lenses made of resin material. During the change in magnification from the wide-angle end to the telephoto end, the first lens group remains stationary with respect to the image plane. When TL is the distance along the optical axis from the object-side lens surface to the image plane of the lens positioned closest to the object in the first lens group, imgH is the maximum image height, f1 is the focal length of the first lens group, and f3 is the focal length of the third lens group, 0.11<imgH / TL<0.20 1.20<f1 / f3<5.00 A zoom lens characterized by satisfying the following conditional equation.

2. When the F-number at the telephoto end is denoted by Fnot, 3.00<Fnot<5.70 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

3. When the F-number at the wide-angle end is denoted as Fnow, 2.00<Fnow<3.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

4. The first lens group has a prism with a reflective surface that is positioned closest to the object, When PL is the distance along the optical axis between the image-side surface of the prism and the object-side lens surface of the lens positioned closest to the object in the first lens group, 0.04<PL / TL<0.07 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

5. When the total focal length of the zoom lens at the wide-angle end is fw and the total focal length of the zoom lens at the telephoto end is ft, 1.70<ft / fw<2.50 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

6. When the total focal length of the zoom lens at its wide-angle end is fw, -2.10<f1 / fw<-1.20 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

7. When the total focal length of the zoom lens at its telephoto end is denoted as ft, -1.10<f1 / ft<-0.50 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

8. When the focal length of the second lens group is f2, -6.00<f1 / f2<-1.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

9. When the focal length of the second lens group is f2, -1.30<f2 / f3<-0.30 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

10. When the total focal length of the zoom lens at its telephoto end is denoted as ft, 0.60<ft / TL<1.30 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

11. When the amount of movement of the second lens group during magnification from the wide-angle end to the telephoto end is denoted as MD2, 0.10<MD2 / TL<0.35 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

12. When the amount of movement of the third lens group during the change in magnification from the wide-angle end to the telephoto end is denoted as MD3, 0.10<MD3 / TL<0.40 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

13. When the back focus at the wide-angle end is denoted as skw, 0.12<skw / TL<0.23 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

14. When the back focus at the telephoto end is denoted as skt, 0.12<skt / TL<0.46 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

15. When the half-angle at the wide-angle end is HOVw and the half-angle at the telephoto end is HOVt, 0.30<HOVt / HOVw<0.65 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

16. When LD11 is defined as half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group, 0.55<LD11 / imgH<1.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

17. When LD11 is half the effective diameter of the object-side lens surface of the lens positioned closest to the object in the first lens group, and LD3L is half the effective diameter of the image-side lens surface of the lens positioned closest to the image in the third lens group, 0.90<LD11 / LD3L<1.40 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

18. When the shape factor of the lens positioned closest to the object in the first lens group is SF11, -12.00<SF11<4.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

19. When the shape factor of the lens positioned closest to the object in the second lens group is SF21, -2.00<SF21<1.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

20. When the shape factor of the lens positioned closest to the object in the third lens group is SF31, -5.00<SF31<1.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

21. When the shape factor of the lens positioned closest to the image in the third lens group is SF3L, -100.00<SF3L<50.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

22. The zoom lens according to claim 1, characterized in that the first lens group includes an aspherical lens having an inflection point.

23. The zoom lens according to claim 1, comprising a prism having a reflective surface arranged in order from the object side to the image side, the first to third lens groups, and a fourth lens group with positive refractive power, characterized in that the distance between each lens group changes when the zoom is changed from the wide-angle end to the telephoto end.

24. The zoom lens according to claim 1, comprising a prism having a reflective surface arranged in order from the object side to the image side, the first to third lens groups, a fourth lens group with positive refractive power, and a fifth lens group with negative refractive power, characterized in that the distance between each lens group changes when the zoom is changed from the wide-angle end to the telephoto end.

25. A zoom lens comprising a prism having a reflective surface arranged in order from the object side to the image side, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, wherein the distance between adjacent lens groups changes when the magnification is changed. During the change in magnification from the wide-angle end to the telephoto end, the first lens group remains stationary with respect to the image plane. When TL is the distance along the optical axis from the object-side lens surface to the image plane of the lens positioned closest to the object in the first lens group, and imgH is the maximum image height, 0.11<imgH / TL<0.20 A zoom lens characterized by satisfying the following conditional equation.

26. An imaging device comprising a zoom lens according to any one of claims 1 to 25 and an image sensor that receives an image formed by the zoom lens.

Images