A macro zoom lens and optical system thereof

Abstract

The present application relates to the field of optical imaging technology, and discloses a micro distance zoom lens and an optical system thereof.The optical system comprises a front group with positive focal length and a rear group with positive focal length arranged in order from an object side to an image side; the front group can be driven to move close to or away from the rear group along a predetermined optical axis of the optical system, the focal length of the front group is f T1 , the focal length of the rear group is f T2 , f T1 , f T2 and f respectively satisfy the relationship: 0.65<|f T1 / f|<1.2, 1.2<|f T2 / f|<1.8.The present application adopts a floating focusing mode, the system magnification can be adjusted in the range of 0.25X to 0.5X, the highest resolution can reach 145lp / mm, can match a 3.45-micron pixel chip, when the maximum chip size is corresponding, the pixels can reach 15 million, and the maximum optical distortion of the full field of view can be as low as 0.07%.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a macro zoom lens and its optical system. Background Technology

[0002] Macro zoom lenses can automatically focus according to the size of the product, providing high-resolution images when shooting at close range, and are currently a common type of optical lens used in machine vision inspection. However, maintaining sharpness across the entire magnification range, minimizing distortion, and controlling aberrations requires complex optical design and high-quality lens components, resulting in a complex structure for macro zoom lenses.

[0003] For optical lenses, lp / mm (line-pairs / mm) and distortion performance are important parameters for measuring lens performance. lp / mm refers to the number of black and white line pairs that can be distinguished per millimeter on the imaging plane, and is a crucial parameter for expressing resolution. Currently available macro zoom lenses have varying degrees of shortcomings in terms of resolution and distortion performance.

[0004] To match the 3.45-micron pixel chip, the production line requires a macro zoom lens with a focal length of 73.5mm (75mm) and a magnification of 0.25X to 0.5X. Furthermore, this lens needs to simultaneously achieve a resolution of 140 lp / mm or higher and optical distortion of less than 0.2%. However, currently, no such lens on the market meets the production line's requirements. Therefore, for those skilled in the art, designing a macro zoom lens with a resolution of 140 lp / mm or higher and optical distortion of less than 0.2%, while fully considering product cost, has become a pressing technical problem to be solved.

[0005] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Summary of the Invention

[0006] The purpose of this invention is to provide a macro zoom lens and its optical system to solve or at least partially solve the technical problems existing in the prior art.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an optical system for a macro zoom lens, comprising a front group having positive optical power and a rear group having positive optical power arranged sequentially from the object side to the image side;

[0009] The front group can be driven to move closer to or further away from the rear group along a predetermined optical axis of the optical system. The distance between the vertex of the rear surface of the front group and the vertex of the front surface of the rear group is denoted as the adjustment spacing DS. The focal length of the optical system is f, and DS and f satisfy the relationship: 0.01 < |DS / f| < 0.42. The distance between the vertex of the rear surface of the rear group and the image plane is BFL, and BFL and f satisfy the relationship: 0.15 < |BFL / f| < 0.28.

[0010] The focal length of the front group is f T1 The focal length of the rear element is f. T2 f T1 f T2 The relationship between f and f is: 0.65 < |f| T1 / f|<1.2, 1.2<|f T2 / f|<1.8.

[0011] Optionally, the front group includes a first lens group with positive optical power, an aperture, and a second lens group with negative optical power arranged sequentially from the object side to the image side.

[0012] The focal length of the first lens group is f. S1 The focal length of the second lens group is f. S2 f S1 f S2 The relationship between f and f is: 0.65 < |f| S1 / f|<0.90, 0.5<|f S2 / f|<4.80.

[0013] Optionally, the first lens group includes a first lens with positive optical power, a second lens with positive optical power, a third lens and a fourth lens arranged sequentially from the object side to the image side, and the third lens and the fourth lens are cemented together to form a first cemented lens group with negative optical power.

[0014] The focal length of the first lens is f G1 The focal length of the second lens is f. G2 The focal length of the first cemented lens group is f. U1 f G1 f G2、 f U1 f and f satisfy the following relation:

[0015] 1. 50<|f G1 / f|<1.90, 1.30<|f G2 / f|<1.90, 2<|f U1 / f|<45.

[0016] Optionally, the second lens group includes a second cemented lens group composed of a fifth lens and a sixth lens bonded together;

[0017] The relative positions of the first lens, the second lens with positive optical power, the third lens, the fourth lens, the fifth lens, and the sixth lens are all fixed.

[0018] Optionally, the distance between the vertices of the front surface of the front group and the vertices of the rear surface of the rear group is L, and L and f satisfy the relationship: 0.62 < |L / f| < 1.35.

[0019] Optionally, the half-image height of the optical system is y', and y' and f satisfy the relationship: 0.08 < |y' / f| < 0.25.

[0020] Optionally, the rear group includes a seventh lens with positive optical power;

[0021] The first, second, third, fourth, fifth, sixth, and seventh lenses are all spherical lenses.

[0022] Optionally, the aperture of the stop is a circular hole, and the center of the circular hole is on the predetermined optical axis;

[0023] The aperture value of the stop can be adjusted.

[0024] Secondly, the present invention provides a macro zoom lens, including the optical system of a macro zoom lens as described above.

[0025] Optionally, the macro zoom lens further includes a focusing structure for driving the entire front group to move closer to or further away from the rear group along the predetermined optical axis, and during the movement of the front group, the optical axis of the front group remains unchanged and always coincides with the predetermined optical axis.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The optical system of the macro zoom lens provided by this invention adopts a floating focusing method, the light-transmitting aperture can be flexibly adjusted, the system magnification can be adjusted within the range of 0.25X to 0.5X, the image square F number is 3.8, the maximum imaging surface is φ19.2mm, the maximum resolution can reach 145lp / mm, it can be matched with a 3.45-micron pixel chip, and at the corresponding maximum chip size, its pixel count can reach 15 million, and the maximum optical distortion across the entire field of view can be as low as 0.07%.

[0028] The present invention has other features and advantages, which will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the optical system of a macro zoom lens provided in an embodiment of the present invention.

[0031] Figure 2 This is the optical distortion curve of an optical system for a macro zoom lens provided in an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the optical system of another macro zoom lens provided in an embodiment of the present invention.

[0033] Figure 4 This is the optical distortion curve of the optical system of another macro zoom lens provided in this embodiment of the invention. Detailed Implementation

[0034] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0035] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0036] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0037] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0038] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0039] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0040] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0041] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0042] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances. Example 1

[0043] Please see Figure 1 , Figure 1 This is a schematic diagram of the optical system of a macro zoom lens provided in an embodiment of the present invention;

[0044] like Figure 1 As shown, the optical system includes a front group T1 with positive optical power and a rear group T2 with positive optical power arranged sequentially from the object side to the image side.

[0045] The front group T1 can be driven to move closer to or further away from the rear group T2 along the predetermined optical axis M of the optical system. The distance between the vertex of the rear surface of the front group T1 and the vertex of the front surface of the rear group T2 is denoted as the adjustment spacing DS. The focal length of the optical system is f, and DS and f satisfy the relationship: 0.01 < |DS / f| < 0.42. The distance between the vertex of the rear surface of the rear group T2 and the image plane is BFL (Back Focal Length). BFL and f satisfy the relationship: 0.15 < |BFL / f| < 0.28.

[0046] The focal length of the front group T1 is f T1 The focal length of the rear group T2 is f. T2 f T1 f T2 The relationship between f and f is: 0.65 < |f| T1 / f|<1.2, 1.2<|f T2 / f|<1.8.

[0047] Furthermore, the front group T1 includes a first lens group S1 with positive optical power, an aperture A0, and a second lens group S2 with negative optical power, arranged sequentially from the object side to the image side.

[0048] The focal length of the first lens group S1 is f S1 The focal length of the second lens group S2 is f. S2 f S1 f S2 The relationship between f and f is: 0.65 < |f| S1 / f|<0.90, 0.5<|f S2 / f|<4.80.

[0049] Specifically, in this embodiment, the first lens group S1 includes a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 and a fourth lens G4 arranged sequentially from the object side to the image side, and the third lens G3 and the fourth lens G4 are cemented together to form a first cemented lens group U1 with negative optical power.

[0050] The focal length of the first lens G1 is f G1 The focal length of the second lens G2 is f G2 The focal length of the first cemented lens group U1 is f. U1 f G1 f G2、 f U1 f and f satisfy the following relation:

[0051] 1. 50<|f G1 / f|<1.90, 1.30<|f G2 / f|<1.90, 2<|f U1 / f|<45.

[0052] The second lens group S2 includes a second cemented lens group U2 composed of a fifth lens G5 and a sixth lens G6 bonded together;

[0053] The relative positions of the first lens G1, the second lens G2 with positive optical power, the third lens G3, the fourth lens G4, the fifth lens G5, and the sixth lens G6 are all fixed.

[0054] In this embodiment, the distance between the vertex of the front surface of the front group T1 and the vertex of the rear surface of the rear group T2 is L, and L and f satisfy the relationship: 0.62 < |L / f| < 1.35.

[0055] In this embodiment, the half-image height of the optical system is y', and y' and f satisfy the relationship: 0.08 < |y' / f| < 0.25.

[0056] Furthermore, the rear group T2 includes a seventh lens G7 with positive optical power;

[0057] The first lens G1, the second lens G2 with positive optical power, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all spherical lenses.

[0058] In this embodiment, the aperture of the stop A0 is a circular hole, and the center of the circular hole is on the predetermined optical axis M;

[0059] The aperture value of aperture A0 can be adjusted.

[0060] The following are specific application examples of optical systems employing the above structure:

[0061] Example 1:

[0062] In this example, the relevant data for the optical system are shown in Table 1;

[0063] Table 1

[0064] surface Radius (mm) Thickness (mm) Refractive index G1 front surface 63.89 2.80 1.497 G1 rear surface flat 2.59 　 G2 front surface 39.80 2.61 1.497 G2 rear surface 104.79 0.10 　 U1 front surface 24.21 3.84 1.497 U1 Adhesive Surface 422.40 5.85 1.620 U1 rear surface 25.59 6.70 　 aperture flat 28.36 　 U2 front surface -15.05 1.50 1.617 U2 adhesive surface 34.92 2.91 1.834 U2 rear surface -58.39 12.54 　 G7 front surface 51.32 2.36 1.497 G7 rear surface flat 16.18 　 Image flat

[0065] It should be noted that in Table 1, "front surface" corresponds to... Figure 1 The left surface of the lens or lens group corresponds to the middle surface, while the rear surface corresponds to the left surface. Figure 1 The middle corresponds to the right surface of the lens or lens group; that is, the "front" corresponds to... Figure 1 On the left, "after" corresponds Figure 1 On the right side.

[0066] In this example, the focal length f of the optical system is 73.52 mm, and the focal length f of the front group T1 is... T1 =68.03mm, the focal length f of the rear element T2. T2 =103.26mm, optical back focal length BFL=16.18mm, half image height y'=9.66mm;

[0067] The focal length f of the first lens group S1 S1 =57.44mm, where the focal length f of the first lens G1 is... G1 =128.55mm, the focal length f of the second lens G2 G2 =127.42mm, the focal length f of the first cemented lens group U1 U1 =-3044.98; Focal length f of the second lens group S2 S2 =-52.81mm;

[0068] In this example, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 is 59.72~84.40mm, that is, the adjustable spacing DS is between 1.25~24.78mm.

[0069] Substituting the above values ​​into the corresponding relations, we obtain:

[0070] |DS / f|=0.02~0.34, |BFL / f|=0.22, |f T1 / f|=0.93,|f T2 / f|=1.40, |f S1 / f|=0.78,|f S2 / f|=0.72,|f G1 / f|=1.75,|f G2 / f|=1.73,|f U1 / f|=41.42, |L / f|=0.81~1.15, |y' / f|=0.13.

[0071] The obtained values ​​satisfy the respective relations, as shown below:

[0072] 0.02<|DS / f|<0.42, 0.15<|BFL / f|<0.28, 0.65<|f T1 / f|<1.2, 1.2<|f T2 / f|<1.8, 0.65<|f S1 / f|<0.90, 0.5<|f S2 / f|<4.80, 1.50<|f G1 / f|<1.90, 1.30<|f G2 / f|<1.90, 2<|f U1 / f|<45, 0.62<|L / f|<1.35, 0.08<|y' / f|<0.25.

[0073] Please continue to refer to this. Figure 2 , Figure 2 This is an optical distortion curve of the optical system of a macro zoom lens provided in an embodiment of the present invention, such as... Figure 2 As shown, the maximum optical distortion across the entire field of view is less than 0.07%.

[0074] Example 2:

[0075] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the optical system of another macro zoom lens provided in an embodiment of the present invention.

[0076] In this example, the relevant data for the optical system are shown in Table 2;

[0077] Table 2

[0078] surface Radius (mm) Thickness (mm) Refractive index G1 front surface 83.82 2.78 1.487 G1 rear surface -255.37 0.28 　 G2 front surface 37.99 7.31 1.457 G2 rear surface 127.78 0.10 　 U1 front surface 20.99 3.85 1.487 U1 Adhesive Surface 247.10 7.64 1.625 U1 rear surface 18.67 2.75 　 aperture flat 26.17 　 U2 front surface -14.74 2.48 1.603 U2 adhesive surface 55.24 7.98 1.883 U2 rear surface -33.03 9.48 　 G7 front surface 53.27 3.98 1.883 G7 rear surface 107.54 14.79 　 Image flat

[0079] It should be noted that in Table 2, "front surface" corresponds to... Figure 3 The left surface of the lens or lens group corresponds to the middle surface, while the rear surface corresponds to the middle surface. Figure 1 The middle corresponds to the right surface of the lens or lens group; that is, the "front" corresponds to... Figure 3 On the left, "after" corresponds Figure 3 On the right side.

[0080] In this example, specifically, the focal length f of the optical system is 75mm, and the focal length f of the front group T1 is...T1 =73.01mm, the focal length f of the rear element T2 T2 =115.57mm, optical back focal length BFL=14.79mm, half image height y'=9.66mm;

[0081] The focal length f of the first lens group S1 S1 =59.49mm, where the focal length f of the first lens G1 is... G1 =129.93mm, the focal length f of the second lens G2 G2 =115.36mm, the focal length f of the first cemented lens group U1 U1 =-249.72; Focal length f of the second lens group S2 S2 =-325.72mm;

[0082] In this example, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 is 65.54~82.23mm, that is, the adjustable spacing DS is between 1.50~16.80mm.

[0083] Substituting the above values ​​into the corresponding relations, we obtain:

[0084] |DS / f|=0.02~0.22, |BFL / f|=0.20, |f T1 / f|=0.97,|f T2 / f|=1.54,|f S1 / f|=0.79,|f S2 / f|=4.34,|f G1 / f|=1.73,|f G2 / f|=1.54,|f U1 / f|=3.33, |L / f|=0.87~1.10, |y' / f|=0.13.

[0085] The obtained values ​​satisfy the respective relations, as shown below:

[0086] 0.02<|DS / f|<0.42, 0.15<|BFL / f|<0.28, 0.65<|f T1 / f|<1.2, 1.2<|f T2 / f|<1.8, 0.65<|f S1 / f|<0.90, 0.5<|f S2 / f|<4.80, 1.50<|f G1 / f|<1.90, 1.30<|f G2 / f|<1.90, 2<|f U1 / f|<45, 0.62<|L / f|<1.35, 0.08<|y' / f|<0.25.

[0087] Please continue to refer to this. Figure 4 , Figure 4 This is an optical distortion curve of the optical system of another macro zoom lens provided in this embodiment of the invention, such as... Figure 4 As shown, the maximum optical distortion across the entire field of view is less than 0.14%.

[0088] In summary, the optical system of the macro zoom lens provided in this embodiment adopts a floating focusing method, the light-transmitting aperture can be flexibly adjusted, the system magnification can be adjusted within the range of 0.25X to 0.5X, the image square F number is 3.8, the maximum imaging surface is φ19.2mm, the maximum resolution can reach 145lp / mm, it can be matched with a 3.45-micron pixel chip, and at the corresponding maximum chip size, its pixel count can reach 15 million, and the maximum optical distortion across the entire field of view can be less than 0.14%.

[0089] Example 2

[0090] This embodiment provides a macro zoom lens, including a focusing structure and an optical system for a macro zoom lens as described in Embodiment 1;

[0091] The focusing structure is used to drive the front group T1 to move closer to or further away from the rear group T2 along the predetermined optical axis M. During the movement of the front group T1, the optical axis of the front group T1 remains unchanged and always coincides with the predetermined optical axis M.

[0092] Since the focusing structure drives the front group T1 to move along the predetermined optical axis M as a whole, the macro zoom lens based on this structure also has good shock resistance.

[0093] Since the optical system has been described in detail in Embodiment 1, it will not be repeated in this embodiment.

[0094] In summary, this embodiment realizes a macro zoom lens with high resolution, the lens magnification can be adjusted in the range of 0.25X to 0.5X, the maximum resolution can reach 145 lp / mm, it can be matched with a 3.45 micrometer pixel chip, and the maximum optical distortion across the entire field of view can be less than 0.14%.

[0095] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical system of a macro zoom lens characterized by comprising: The front group and the rear group are sequentially arranged from the object side to the image side, and the front group has positive refractive power and the rear group has positive refractive power; The front group is sequentially arranged from the object side to the image side, and the front group comprises a first lens group having positive refractive power, a diaphragm, and a second lens group having negative refractive power; The first lens group is sequentially arranged from the object side to the image side, and the first lens group comprises a first lens having positive refractive power, a second lens having positive refractive power, a third lens, and a fourth lens, and the third lens and the fourth lens are glued to form a first glued lens group having negative refractive power; The second lens group comprises a second glued lens group formed by a fifth lens and a sixth lens; The rear group comprises a seventh lens having positive refractive power; The front group can be driven to move towards or away from the rear group along a predetermined optical axis of the optical system, the distance between the vertex of the rear surface of the front group and the vertex of the front surface of the rear group is recorded as an adjustment interval DS, the focal length of the optical system is f, and DS and f satisfy the relationship: 0.01<|DS / f|<0.42; the distance between the vertex of the rear surface of the rear group and the image surface is BFL, and BFL and f satisfy the relationship: 0.15<|BFL / f|<0.28; The focal length of the front group is f T1 , and the focal length of the rear group is f T2 , f T1 , f T2 and f respectively satisfy the relationship: 0.65<|f T1 / f|<1.2, 1.2<|f T2 / f|<1.

8.

2. The optical system of a macro zoom lens according to claim 1, wherein The focal length of the first lens group is f S1 , the focal length of the second lens group is f S2 , f S1 , f S2 and f respectively satisfy the relationship: 0.65<|f S1 / f|<0.90, 0.5<|f S2 / f|<4.

80.

3. The optical system of a macro zoom lens according to claim 2, wherein The focal length of the first lens is f G1 , the focal length of the second lens is f G2 , the focal length of the first cemented lens group is f U1 , f G1 , f G2、 f U1 and f respectively satisfy the relationship:

1. 50<|f G1 / f|<1.90, 1.30<|f G2 / f|<1.90, 2<|f U1 / f|<45.

4. The optical system of a macro zoom lens according to claim 3, wherein The relative positions between the first lens, the second lens having positive refractive power, the third lens, the fourth lens, the fifth lens, and the sixth lens are fixed.

5. The optical system of a macro zoom lens according to claim 1, wherein The distance between the vertex of the front surface of the front group and the vertex of the rear surface of the rear group is L, and L and f satisfy the relationship: 0.62<|L / f|<1.

35.

6. The optical system of a macro zoom lens according to claim 1, wherein The half image height of the optical system is y', and y' and f satisfy the relationship: 0.08<|y' / f|<0.

25.

7. The optical system of a macro zoom lens according to claim 4, wherein The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all spherical lenses.

8. The optical system of a macro zoom lens according to claim 2, wherein The aperture of the diaphragm is a circular hole, and the center of the circular hole is on the predetermined optical axis; The aperture value of the diaphragm can be adjusted.

9. A macro zoom lens characterized by comprising: An optical system comprising a macro zoom lens according to any one of claims 1-8.

10. The macro zoom lens of claim 9, wherein Further comprising a focusing structure for driving the front group as a whole to move towards or away from the rear group along the predetermined optical axis, and during the movement of the front group, the optical axis of the front group remains unchanged and always coincides with the predetermined optical axis.

Images