Zoom lens, image pickup apparatus, and image pickup system

Abstract

The invention relates to a zoom lens, an image pickup apparatus, and an image pickup system. The zoom lens includes a plurality of lens units including, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. A distance between adjacent lens units changes during zooming. The second lens unit includes at least one negative lens. A predetermined inequality is satisfied.

Description

Technical Field

[0001] One of the aspects of the embodiments relates to a zoom lens suitable for digital video cameras, digital still cameras, broadcast cameras, film-based cameras, surveillance cameras, and the like. Background Art

[0002] It is conventionally known that a zoom lens includes first to fourth lens units having negative, positive, negative and positive refractive powers from the object side to the image side, and has a small size and can efficiently ensure the magnification variation ratio. Japanese Patent Laid-Open No. 2005-283648 discloses a zoom lens, which includes first to fourth lens units having negative, positive, negative and positive refractive powers from the object side to the image side, and has a magnification variation ratio of about 5 times and a half angle of view of about 39 degrees, wherein all lens units move during zooming. Japanese Patent Laid-Open No. 2019-174711 discloses a zoom lens, which includes first to fourth lens units having negative, positive, negative and positive refractive powers from the object side to the image side, and has a magnification variation ratio of about two times, and the half angle of view is about 63 degrees, wherein the first to third lens units move during zooming, and the first lens unit includes five lenses.

[0003] In the zoom lens disclosed in Japanese Patent Laid-Open No. 2005-283648, in attempting a wider angle while maintaining the lens arrangement at the wide-angle end disclosed, the shape of the first lens unit cannot be established due to the enlargement of the front lens, and the number of lenses in the first lens unit is increased. As a result, the diameter, total length, and weight are increased.

[0004] In the zoom lens disclosed in Japanese Patent Laid-Open No. 2019-174711, due to the large number of lenses in the first lens unit, the first lens unit and thus the zoom lens are not suitable in diameter, total length, and weight. Moreover, since the magnification change rate is about two times, the diameter, total length, and weight will be further increased in an attempt to increase the magnification change. Summary of the invention

[0005] A zoom lens according to one aspect of the present disclosure includes a plurality of lens units, which include, from the object side to the image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. The distance between adjacent lens units changes during zooming. The second lens unit includes at least one negative lens. The following inequality is satisfied:

[0006] 20 <v2n<28

[0007] 0.00 <f2 / f4<0.40

[0008] 12 <Lw / fw<55

[0009] Wherein v2n is the minimum value of the Abbe number of the negative lens, f2 is the focal length of the second lens unit, f4 is the focal length of the fourth lens unit, Lw is the total optical length of the zoom lens at the wide angle end, and fw is the focal length of the zoom lens at the wide angle end. An image pickup device and an image pickup system each having the above-mentioned zoom lens also constitute another aspect of the present disclosure.

[0010] Further features of various embodiments of the present disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a cross-sectional view of a zoom lens according to Example 1.

[0012] Figure 2A , Figure 2B and Figure 2C are aberration diagrams of the zoom lens according to Example 1 at the wide-angle end, the intermediate focal length, and the telephoto end.

[0013] Figure 3 is a cross-sectional view of a zoom lens according to Example 2.

[0014] Figure 4A , Figure 4B and Figure 4C are aberration diagrams of the zoom lens according to Example 2 at the wide-angle end, the intermediate focal length, and the telephoto end.

[0015] Figure 5 is a cross-sectional view of a zoom lens according to Example 3.

[0016] Fig. 6A , Figure 6B and Figure 6C are aberration diagrams of the zoom lens according to Example 3 at the wide-angle end, the intermediate focal length, and the telephoto end.

[0017] Figure 7 is a cross-sectional view of a zoom lens according to Example 4.

[0018] Fig. 8A , Figure 8B and Figure 8C are aberration diagrams of the zoom lens according to Example 4 at the wide-angle end, the intermediate focal length, and the telephoto end.

[0019] Fig. 9 is a cross-sectional view of a zoom lens according to Example 5.

[0020] Fig. 10A , Fig. 10B and Fig. 10C are aberration diagrams of the zoom lens according to Example 5 at the wide-angle end, the intermediate focal length, and the telephoto end.

[0021] Fig.11 is a schematic diagram of an image pickup device.

[0022] Fig. 12A and Fig. 12B is a schematic diagram of an image pickup device. DETAILED DESCRIPTION

[0023] Now, with reference to the accompanying drawings, a detailed description of embodiments according to the present disclosure will be given. Corresponding elements in various figures will be marked with the same reference numerals, and their repeated description will be omitted.

[0024] Figure 1 , Figure 3 , Figure 5 , Figure 7 and Fig. 9 They are respectively cross-sectional views of zoom lenses according to Examples 1 to 5. The zoom lens according to each example is an optical system used for an image pickup apparatus such as a digital video camera, a digital still camera, a broadcast camera, a film-based camera, and a surveillance camera.

[0025] In each cross-sectional view, the left side is the object side, and the right side is the image side. The zoom lens according to each example includes a plurality of lens units. In the present specification, a lens unit is a group of lenses that moves or remains stationary during zooming. That is, in the zoom lens according to each example, the distance between adjacent lens units changes during zooming. The lens unit may include one or more lenses. The lens unit may include an aperture stop.

[0026] The zoom lens according to each example includes a plurality of lens units as described above. The plurality of lens units include, in order from the object side to the image side, a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, a third lens unit L3 having a negative refractive power, and a fourth lens unit L4 having a positive refractive power.

[0027] SP represents an aperture stop (aperture). P represents a glass block such as a panel of a CCD sensor or a low-pass filter. I represents an image plane, and in the case where the zoom lens according to each example is used as an imaging optical system of a digital still camera or a digital video camera, an imaging surface of a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is placed on the image plane I. In the case where the zoom lens according to each example is used as an imaging optical system of a film-based camera, a photosensitive surface corresponding to a film surface is placed on the image plane I.

[0028] In the zoom lens according to each example, during zooming from the wide angle end to the telephoto end, each lens unit is moved in the arrow direction. The solid line and the dotted line are movement trajectories during focusing on an object at infinity and an object at a short distance, respectively. In each example, the second lens unit L2 at the telephoto end is located on the object side of the second lens unit L2 at the wide angle end.

[0029] In the zoom lenses according to Examples 1 to 4, the third lens unit L3 is used as a focusing unit, and in the zoom lens according to Example 5, the fourth lens unit L4 is used as a focusing unit. The first lens unit L1 may be used as a focusing unit, or the first lens unit L1 and the second lens unit L2 may be integrally used as a focusing unit.

[0030] Figure 2A , Figure 4A , Fig. 6A , Fig. 8A and Fig. 10A They are aberration diagrams of the zoom lenses according to Examples 1 to 5 at the wide-angle end, respectively. Figure 2B , Figure 4B , Figure 6B , Figure 8B and Fig. 10B Aberration diagrams of the zoom lenses according to Examples 1 to 5 at the intermediate focal length, respectively. Figure 2C , Figure 4C , Figure 6C , Figure 8C and Fig. 10C Aberration diagrams of the zoom lenses according to Examples 1 to 5 at the telephoto end, respectively.

[0031] In the spherical aberration diagram, Fno represents the F number and indicates the amount of spherical aberration for the d-line (wavelength 587.6nm) and the g-line (wavelength 435.8nm). In the astigmatism diagram, S represents the amount of astigmatism on the sagittal image plane, and M represents the amount of astigmatism on the meridional image plane. The distortion aberration diagram illustrates the amount of distortion for the d-line. The chromatic aberration diagram illustrates the amount of chromatic aberration for the g-line. ω is the imaging half angle of view (°).

[0032] A description will be given of a characteristic configuration of the zoom lens according to each example.

[0033] The second lens unit L2 includes at least one negative lens, thereby making it possible to correct longitudinal chromatic aberration.

[0034] The zoom lens according to each example satisfies the following inequalities (1) to (3):

[0035] 20<v2n<28 (1)

[0036] 0.00<f2 / f4<0.40 (2)

[0037] 12 <Lw / fw<55 (3)

[0038] Where v2n is the minimum value of the Abbe number of the negative lens included in the second lens unit L2, f2 is the focal length of the second lens unit L2, f4 is the focal length of the fourth lens unit L4, Lw is the total optical length (total lens length) of the zoom lens at the wide angle end, and fw is the focal length of the zoom lens at the wide angle end. In this specification, the Abbe number is a value based on the d line. The total optical length is the distance on the optical axis from the lens surface on the object side of the first lens unit L1 to the lens surface on the image side of the fourth lens unit L4 plus the back focal length. In the case where a glass block or the like is placed in the back focal length, the extension amount caused by the glass block or the like is also added to the back focal length.

[0039] Inequality (1) defines the minimum value of the Abbe number of the negative lens included in the second lens unit L2. When the value of v2n becomes lower than the lower limit of inequality (1), longitudinal chromatic aberration tends to be overcorrected, especially on the short wavelength side. When the value of v2n becomes higher than the upper limit of inequality (1), it becomes difficult to correct longitudinal chromatic aberration.

[0040] Inequality (2) defines the ratio of the focal length of the second lens unit L2 to the focal length of the fourth lens unit L4. In inequality (2), the value of f2 / f4 never becomes lower than the lower limit. In the case where the value of f2 / f4 becomes higher than the upper limit of inequality (2), efficient zooming becomes difficult and the total length becomes too long to ensure the desired magnification change rate.

[0041] Inequality (3) defines the ratio of the total optical length at the wide-angle end to the focal length of the zoom lens at the wide-angle end. In the case where the value of Lw / fw becomes lower than the lower limit of inequality (3), a wide angle cannot be obtained. Alternatively, in order to widen the viewing angle, the refractive power of the first lens unit L1 may be increased and it becomes difficult to correct field curvature and lateral chromatic aberration. In the case where the value of Lw / fw becomes higher than the upper limit of inequality (3), the total length becomes longer.

[0042] Inequalities (1) to (3) can be replaced by the following inequalities (1a) to (3a):

[0043] 20.2 <v2n<27.7 (1a)

[0044] 0.120 <f2 / f4<0.395 (2a)

[0045] 13 <Lw / fw<26 (3a)

[0046] Inequalities (1) to (3) can be replaced by the following inequalities (1b) to (3b):

[0047] 20.3 <v2n<27.6 (1b)

[0048] 0.130 <f2 / f4<0.393 (2b)

[0049] 13.5 <Lw / fw<25.5 (3b)

[0050] A description will now be given of configurations that may be satisfied in the zoom lens according to each example.

[0051] The first lens unit L1 may include three lenses or less. A large number of lenses is advantageous for correcting aberrations, but may easily increase the weight, total length, and diameter of the front lens of the first lens unit L1 or the entire zoom lens.

[0052] A description will now be given of conditions that the zoom lens according to each example may satisfy. The zoom lens according to each example may satisfy one or more of the following inequalities (4) to (10):

[0053] 0.00 <f1 / f3<0.41 (4)

[0054] -0.95 <f1 / f2<-0.55 (5)

[0055] -0.48 <f2 / f3<-0.12 (6)

[0056] -1.43<f3 / f4<-0.63 (7)

[0057] -1.51 <D1 / f1<-0.81 (8)

[0058] 0.00 <D34w / Lw<0.03 (9)

[0059] 3.4 <z<9.0 (10)

[0060] Wherein f1 is the focal length of the first lens unit L1, f3 is the focal length of the third lens unit L3, D1 is the distance on the optical axis from the lens surface of the first lens unit L1 closest to the object to the lens surface closest to the image plane, D34w is the distance on the optical axis between the lens surface of the third lens unit L3 closest to the image plane and the lens surface of the fourth lens unit L4 closest to the object at the wide-angle end, and z is the magnification change rate.

[0061] Inequality (4) defines the ratio of the focal length of the first lens unit L1 to the focal length of the third lens unit L3. In inequality (4), the value of f1 / f3 never falls below the lower limit. When the value of f1 / f3 becomes higher than the upper limit of inequality (4), the refractive power of the first lens unit L1 becomes weak and wider angles become difficult.

[0062] Inequality (5) defines the ratio of the focal length of the first lens unit L1 to the focal length of the second lens unit L2. When the value of f1 / f2 becomes lower than the lower limit of inequality (5), a wider angle becomes difficult. When the value of f1 / f2 becomes higher than the upper limit of inequality (5), it becomes difficult to correct field curvature and lateral chromatic aberration. Alternatively, efficient zooming becomes difficult, and the total length becomes too long to ensure the desired magnification change rate.

[0063] Inequality (6) defines the ratio of the focal length of the second lens unit L2 to the focal length of the third lens unit L3. When the value of f2 / f3 becomes lower than the lower limit of inequality (6), efficient zooming becomes difficult, and the total length becomes too long to ensure the desired magnification change rate. When the value of f2 / f3 becomes higher than the upper limit of inequality (6), it becomes difficult to correct spherical aberration and coma.

[0064] Inequality (7) defines the ratio of the focal length of the third lens unit L3 to the focal length of the fourth lens unit L4. When the value of f3 / f4 becomes lower than the lower limit of inequality (7), it becomes difficult to suppress the fluctuation of field curvature during zooming. When the value of f3 / f4 becomes higher than the upper limit of inequality (7), it becomes difficult to suppress the fluctuation of spherical aberration during zooming.

[0065] Inequality (8) defines the ratio of the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image plane of the first lens unit L1 to the focal length of the first lens unit L1. When the value of D1 / f1 becomes lower than the lower limit of inequality (8), the weight, total length, and diameter of the front lens of the zoom lens increase. When the value of D1 / f1 becomes higher than the upper limit of inequality (8), it becomes difficult to satisfy both a wider angle and aberration correction.

[0066] Inequality (9) defines the ratio of the distance on the optical axis from the lens surface closest to the image plane of the third lens unit L3 to the lens surface closest to the object of the fourth lens unit L4 at the wide-angle end to the total optical length at the wide-angle end. In inequality (9), the value of D34w / Lw never falls below the lower limit. In the case where the value of D34w / Lw becomes higher than the upper limit in inequality (9), it becomes difficult to suppress the fluctuation of spherical aberration during zooming.

[0067] Inequality (10) defines the magnification change rate. When the value of z becomes lower than the lower limit of inequality (10), the necessity of the present disclosure decreases. When the value of z becomes higher than the upper limit of inequality (10), the weight, total length, and diameter of the front lens of the zoom lens increase.

[0068] Inequalities (4) to (10) can be replaced by the following inequalities (4a) to (10a):

[0069] 0.10 <f1 / f3<0.39 (4a)

[0070] -0.90 <f1 / f2<-0.58 (5a)

[0071] -0.46<f2 / f3<-0.13 (6a)

[0072] -1.37 <f3 / f4<-0.66 (7a)

[0073] -1.44<D1 / f1<-0.85 (8a)

[0074] 0.010 <D34w / Lw<0.025 (9a)

[0075] 3.6<z<8.5 (10a)

[0076] Inequalities (4) to (10) can be replaced by the following inequalities (4b) to (10b):

[0077] 0.11 <f1 / f3<0.38 (4b)

[0078] -0.88<f1 / f2<-0.60 (5b)

[0079] -0.45<f2 / f3<-0.14 (6b)

[0080] -1.30 <f3 / f4<-0.68 (7b)

[0081] -1.40 <D1 / f1<-0.90 (8b)

[0082] 0.010 <D34w / Lw<0.020 (9b)

[0083] 3.7 <z<8.0 (10b)

[0084] Numerical Examples 1 to 5 corresponding to Examples 1 to 5, respectively, will be described below.

[0085] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axis distance (distance on the optical axis) between the mth surface and the (m+1)th surface, where m is the surface number counted from the light incident side. nd represents the refractive index of each optical member for the d line, and vd represents the Abbe number of the optical member. The Abbe number of a certain material is expressed as follows:

[0086] vd=(Nd-1) / (NF-NC)

[0087] Wherein Nd, NF and NC are the refractive indices of the d line (587.6 nm), F line (486.1 nm) and C line (656.3 nm) in the Fraunhofer line, respectively.

[0088] In each numerical example, d, focal length (mm), F number, and half angle of view (degrees) are values ​​when the zoom lens of each example is in a focused state on an object at infinity. The half angle of view is a value determined by ray tracing. The "back focal length" is the distance on the optical axis from the last lens surface (the lens surface closest to the image plane) to the paraxial image surface, expressed as an air equivalent length, and is a value when the glass block is not included. The "total lens length" is the length of the zoom lens excluding the glass block, and the back focal length is added to the distance on the optical axis from the frontmost surface (the lens surface closest to the object) to the rearmost surface. WIDE represents the wide-angle end, MIDDLE represents the centered (middle) zoom position, and TELE represents the telephoto end.

[0089] In the case where the optical surface is an aspherical surface, an asterisk * is added to the right side of the surface number. The aspherical shape is expressed as follows:

[0090] 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

[0091] Where X is the displacement from the surface vertex in the direction of the optical axis, 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 cone constant, and A4, A6, A8, and A10 are aspheric coefficients of each order. The "e±XX" in each aspheric coefficient means "×10 ±XX ”. The coefficients not listed in each numerical example are zero.

[0092] Numerical Example 1

[0093] Unit: mm

[0094] Surface data

[0095]

[0096]

[0097] Aspheric surface data

[0098] Surface 8

[0099] K=-1.57466e+00

[0100] Surface 9

[0101] K=0.00000e+00 A4=5.62163e-05

[0102] Various data

[0103]

[0104]

[0105] Zoom lens unit data

[0106] Numerical Example 2

[0107] Unit: mm

[0108] Surface data

[0109]

[0110]

[0111] Aspheric surface data

[0112] Surface 3

[0113] K=1.28585e+00 A4=2.45808e-05

[0114] Surface 7

[0115] K=-1.93828e+00 A4=7.55192e-05

[0116] Surface 8

[0117] K=-9.08920e-01 A4=9.41364e-05

[0118] Surface 15

[0119] K=-1.09444e+00 A4=4.35236e-05

[0120] Various data

[0121]

[0122]

[0123] Zoom lens unit data

[0124]

[0125] Numerical Example 3

[0126] Unit: mm

[0127] Surface data

[0128]

[0129]

[0130] Aspheric surface data

[0131] Surface 8

[0132] K=1.73438e+00 A4=-9.56202e-06

[0133] Surface 9

[0134] K=-1.01922e+00 A4=8.83438c-05

[0135] Various data

[0136]

[0137] Zoom lens unit data

[0138]

[0139] Numerical Example 4

[0140] Unit: mm

[0141] Surface data

[0142]

[0143]

[0144] Aspheric surface data

[0145] Surface 8

[0146] K=-3.20404e-01 A4=-2.55905e-05

[0147] Surface 9

[0148] K=2.83697e+00 A4=4.40781e-05

[0149] Various data

[0150]

[0151] Zoom lens unit data

[0152]

[0153] Numerical Example 5

[0154] Unit: mm

[0155] Surface data

[0156]

[0157]

[0158] Aspheric surface data

[0159] Surface 8

[0160] K=-1.97205e+00 A4=1.86383e-04

[0161] Surface 9

[0162] K=-8.69262e-01 A4=3.02826e-04

[0163] Various data

[0164]

[0165] Zoom lens unit data

[0166]

[0167]

[0168] Table 1 summarizes the various values ​​for each numerical example.

[0169] Table 1

[0170]

[0171] Image pickup device

[0172] Reference now Fig.11 , a description will be given of an illustrative digital still camera (image pickup device) using a zoom lens according to any one of the above-described examples as an imaging optical system. Fig.11, reference numeral 10 denotes a camera body, and reference numeral 11 denotes an imaging optical system composed of any one of the zoom lenses described in Examples 1 to 5. Reference numeral 12 denotes a solid-state image sensor (photoelectric conversion element), such as a CCD sensor or a CMOS sensor, which is built into the camera body and receives an optical image formed by the imaging optical system 11 and performs photoelectric conversion on it. The camera body 10 may be a so-called single-lens reflex camera having a fast-rotating mirror, or a so-called mirrorless camera having no fast-rotating mirror.

[0173] Therefore, applying the zoom lens according to each example to an image pickup apparatus such as a digital still camera can provide an image pickup apparatus having a compact lens.

[0174] Image pickup system

[0175] The image pickup system (surveillance camera system) may include a zoom lens according to any one of the above examples and a control unit configured to control the zoom lens. In this case, the control unit may control the zoom lens so that each lens unit moves as described above during zooming, focusing, and image stabilization. At this time, the control unit does not need to be integrated with the zoom lens and may be separated from the zoom lens. For example, the control device may be located away from a driving unit configured to drive each lens in the zoom lens and include a transmitter configured to transmit a control signal (command) for controlling the zoom lens. This control unit may remotely control the zoom lens.

[0176] The control unit may include an operation unit configured to remotely control the zoom lens, such as a controller or a button, so that the zoom lens is controlled according to a user input to the operation unit. For example, the operation unit may include a zoom-in button and a zoom-out button. In this case, the control unit sends a signal to a drive unit in the zoom lens so that when the user presses the zoom-in button, the magnification of the zoom lens increases, and when the user presses the zoom-out button, the magnification of the zoom lens decreases.

[0177] The image pickup system may include a display unit, such as a liquid crystal panel, configured to display information about the zoom (movement state) of the zoom lens. The information about the zoom of the zoom lens includes, for example, the zoom ratio (zoom state) and the movement amount (movement state) of each lens unit. In this case, the user can remotely operate the zoom lens via the operation unit while viewing the information about the zoom of the zoom lens shown on the display unit. The display unit and the operation unit can be integrated, for example, by adopting a touch panel or the like.

[0178] Fig. 12A and Fig. 12Bis a schematic diagram of an image pickup device (monitoring camera) using the zoom lens according to each example as an imaging optical system.

[0179] exist Fig. 12A , reference numeral 21 denotes a monitoring camera body, and reference numeral 22 denotes a solid-state image sensor (photoelectric conversion element), such as a CCD sensor or a CMOS sensor, which is built into the camera body and receives an object image formed by a lens unit 26. Reference numeral 23 denotes a memory unit that records information corresponding to the object image photoelectrically converted by the solid-state image sensor 22. Reference numeral 24 denotes a network cable for transmitting the object image photoelectrically converted by the solid-state image sensor 22.

[0180] Fig. 12B An example of using the image pickup device with a dome-shaped cover 25 attached and attached to a ceiling is illustrated. Reference numeral 20 denotes a portion not covered by the dome-shaped cover 25.

[0181] Therefore, applying the image pickup device according to this example to an optical device such as a surveillance camera can provide a compact optical device with high optical performance.

[0182] The image pickup device is not limited to the surveillance camera, and can also be used for a video camera, a digital camera, or the like.

[0183] In the case where an electronic image sensor such as a CCD is used as the image sensor, the quality of the output image can be further improved by electronically correcting the aberration.

[0184] Although the disclosure has described example embodiments, it is to be understood that some embodiments are not limited to the disclosed embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0185] Each example may provide a zoom lens that may have a small size, a wide angle, and high optical performance.

Claims

1. A zoom lens, comprising: a plurality of lens units, the plurality of lens units including, in order from the object side to the image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power, It is characterized in that the distance between adjacent lens units changes during zooming, wherein the second lens unit comprises at least one negative lens, and The following inequalities are satisfied: 20 <v2n<28 0.00 <f2 / f4<0.40 12 <Lw / fw<55 Wherein v2n is the minimum value of the Abbe number of the negative lens, f2 is the focal length of the second lens unit, f4 is the focal length of the fourth lens unit, Lw is the total optical length of the zoom lens at the wide angle end, and fw is the focal length of the zoom lens at the wide angle end.

2. The zoom lens according to claim 1, characterized in that The inequality is satisfied: 0.00 <f1 / f3<0.41 Wherein f1 is the focal length of the first lens unit, and f3 is the focal length of the third lens unit.

3. The zoom lens according to claim 1, characterized in that The inequality is satisfied: -0.95 <f1 / f2<-0.55 Wherein f1 is the focal length of the first lens unit.

4. The zoom lens according to claim 1, characterized in that The inequality is satisfied: -0.48<f2 / f3<-0.12 Wherein f3 is the focal length of the third lens unit.

5. The zoom lens according to claim 1, characterized in that The inequality is satisfied: -1.43<f3 / f4<-0.63 Wherein f3 is the focal length of the third lens unit.

6. The zoom lens according to claim 1, characterized in that The first lens unit includes three lenses or less.

7. The zoom lens according to claim 1, characterized in that The inequality is satisfied: -1.51<D1 / f1<-0.81 Wherein D1 is the distance on the optical axis from the lens surface of the first lens unit closest to the object to the lens surface closest to the image plane, and f1 is the focal length of the first lens unit.

8. The zoom lens according to claim 1, characterized in that The inequality is satisfied: 0.00<D34w / Lw<0.03 Wherein D34w is the distance on the optical axis from the lens surface of the third lens unit closest to the image plane to the lens surface of the fourth lens unit closest to the object at the wide angle end.

9. The zoom lens according to claim 1, characterized in that The inequality is satisfied: 3.4＜z＜9.0 Where z is the rate of change.

10. The zoom lens according to claim 1, characterized in that The second lens unit at the telephoto end is located on the object side of the second lens unit at the wide-angle end.

11. An image pickup device, comprising: The zoom lens according to any one of claims 1 to 10; as well as An image sensor is configured to receive an image formed by the zoom lens.

12. An image pickup system comprising: The zoom lens according to any one of claims 1 to 10; as well as A control unit is configured to control the zoom lens during zooming. 13 . The image pickup system according to claim 12 , wherein the control unit is separate from the zoom lens, and comprises a transmitter configured to transmit a control signal for controlling the zoom lens. 14 . The image pickup system according to claim 12 , wherein the control unit is separate from the zoom lens, and includes an operation unit configured to operate the zoom lens. 15 . The image pickup system according to claim 12 , further comprising a display unit configured to display information on zooming of the zoom lens.

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