CN111694129A - Middle focus video lens with 65mm focal length - Google Patents
Middle focus video lens with 65mm focal length Download PDFInfo
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- CN111694129A CN111694129A CN202010686101.4A CN202010686101A CN111694129A CN 111694129 A CN111694129 A CN 111694129A CN 202010686101 A CN202010686101 A CN 202010686101A CN 111694129 A CN111694129 A CN 111694129A
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- lens
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- focal length
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
- G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/009—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras having zoom function
Abstract
The invention discloses a middle focus video lens with a focal length of 65mm, which sequentially comprises a first lens group, an iris diaphragm and a second lens group from an object side to an image side, wherein the first lens group has positive focal power, the position of the first lens group can move along the optical axis direction, the second lens group has positive focal power, the position of the second lens group can move along the optical axis direction, the first lens group comprises a first positive lens group and a first negative lens group, the first positive lens group comprises at least one positive lens and at least one negative positive cemented lens, the first negative lens group comprises at least one positive lens and at least one negative lens, the second lens group comprises at least one negative lens and two negative positive cemented lenses, and the first lens group and the second lens group can move to realize focusing, so that the size is effectively reduced, the light weight is facilitated, and the lens is provided with a plurality of cemented lenses, the chromatic aberration and the distortion are facilitated to be corrected, and the image quality definition.
Description
Technical Field
The invention relates to the technical field of lenses, in particular to a medium focus video lens with a focal length of 65 mm.
Background
In recent years, a trend of taking original videos to record life appears on the network, namely Vlog is called in English, the video blog means, and naturally, Vlogger is taken as the videos, namely, bloggers sharing the videos on a platform, and with the rise of mobile phone videos, people are Vlogger in the future, so that except mobile phones, the requirements on equipment and equipment on a higher layer are high, along with the development of the short video field, the video lens is applied more and more in the short video shooting field, but the conventional video lens is small in light-passing aperture, large in volume and weight, small in imaging surface and not clear enough in image quality, and the market requirements are difficult to meet.
Disclosure of Invention
The invention aims to provide a middle-focus video lens with a focal length of 65mm, wherein a first lens group and a second lens group can move to realize focusing, so that the size is effectively reduced, the light weight is facilitated, the lens is provided with a plurality of cemented lenses, chromatic aberration and distortion are facilitated to be corrected, the image quality definition is improved, and the problems of large size, small imaging surface and poor image quality of the conventional video lens are solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a middle focus video lens with 65mm focal length sequentially comprises a first lens group, an iris diaphragm and a second lens group from an object side to an image side;
the first lens group has positive focal power and can move along the direction of an optical axis;
the second lens group has positive focal power and can move along the direction of the optical axis;
the first lens group comprises a first positive lens group and a first negative lens group, and the first positive lens group comprises at least one positive lens and a negative positive combined lens;
the first negative lens group comprises at least one positive lens and at least one negative lens;
the second lens group comprises at least one negative lens and two negative and positive cemented lenses;
the first lens group and the second lens group satisfy the following formula:
1<f1/f2<3；-0.5<f12/f1<-0.1；
wherein f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f12 represents the focal length of the first negative lens group.
Therefore, the focal power of the first lens group and the second lens group meets the relation of 1< f1/f2<3, so that the lens has enough rear working distance, the use requirement is met, the focal power of the first negative lens group and the first lens group meets the relation of-0.5 < f12/f1< -0.1, the field angle of the lens is ensured, the correction of the phase difference of the full field of view is facilitated, the first lens group and the second lens group can move in a matched mode to zoom, the length of the lens is effectively reduced, the first lens group is provided with the cemented lens, the second lens group is provided with the two cemented lenses, the chromatic aberration can be effectively corrected, the negative lens of the second lens group can increase the imaging surface, and the definition of image quality is improved.
In some embodiments, the positive lens of the first positive lens group is a first lens close to the object side, and a lens surface of the first lens is curved toward the object side.
Thus, the mirror surface of the first lens is curved toward the object side, so that the viewing angle can be increased, the aperture of the light transmission can be increased, and the amount of light transmission can be increased.
In some embodiments, the negative lens of the second lens group is a tenth lens close to the image side, the tenth lens is crescent-shaped, and a mirror surface of the tenth lens is curved toward the image side.
From this, the tenth lens is crescent lens, and is crooked to like, can effectively balance the coma and the astigmatism of front and back lens group for the cooperation tolerance sensitivity greatly reduced of front and back lens group also does benefit to the increase imaging surface.
In some embodiments, the refractive index of the positive lens of the cemented lens of the first lens group is between 1.4 and 1.5.
Therefore, the refractive index of the third lens is between 1.4 and 1.5.
In some embodiments, the refractive index of the positive lenses of both the cemented lenses of the second lens group is between 1.7 and 1.9.
Therefore, the refractive indexes of the seventh lens and the ninth lens are between 1.7 and 1.9, and the higher refractive index can effectively turn the wide-angle incident light, so that the maximum deflection angle is less than 25 degrees when the large-angle light enters the system diaphragm, and the total length of the light path can be effectively shortened and the number of the lenses can be reduced.
In some embodiments, at least one of the cemented lenses of the second lens group has an abbe number difference of 10 to 20.
Therefore, the abbe number difference between the eighth lens and the ninth lens is 10 to 20, and/or the abbe number difference between the sixth lens and the seventh lens is 10 to 20, preferably the abbe number difference between the eighth lens and the ninth lens is 12, and the abbe number difference between 10 to 20 is favorable for correcting chromatic aberration.
In some embodiments, the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 0.2< BFL/f < 1.
Therefore, the lens adopts a reverse long-distance light path structure, and can ensure enough rear working distance by meeting the relation that 0.2< BFL/f < 1.
In some embodiments, the total length of the first mirror to the last mirror of the lens is between 50 and 70 mm, and the maximum aperture of the lens is between 35 and 45 mm.
The invention has the beneficial effects that: the first lens group and the second lens group can move to realize focusing, and lenses with high refractive index are properly arranged, so that the total length of a light path is effectively shortened, the number of the lenses is reduced, the size is reduced, and the light weight is facilitated;
moreover, the first lens group and the second lens group are both provided with cemented lenses which can correct chromatic aberration and distortion, and the difference value of the abbe numbers of the cemented lenses of the first lens group is between 10 and 20, so that chromatic aberration can be further corrected;
furthermore, the tenth lens of the second lens group is crescent, which can effectively balance the coma and astigmatism of the front and rear lens groups, so that the sensitivity of the fit tolerance of the front and rear lens groups is greatly reduced, and the imaging surface is increased to a certain extent.
Drawings
FIG. 1 is a diagram of a mid-focus video lens of 65mm focal length according to the present invention;
FIG. 2 is an axial coloring differential view of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 3 is a schematic diagram of vertical axis chromatic aberration of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 4 is a schematic diagram of field curvature distortion of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 5 is a diagram illustrating the light aberration of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 6 is a schematic diagram of a diffuse spot of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 7 is a schematic MTF diagram of a mid-focus video lens with a focal length of 65mm according to the present invention;
FIG. 8 is a schematic diagram of MTF and field of view of a mid-focus video lens with a focal length of 65mm according to the present invention;
wherein: g1-first lens group; g11 — first positive lens group; g12 — first negative lens set; g2-second lens group; l1-first lens; l2-second lens; l3-third lens; l4-fourth lens; l5-fifth lens; l6-sixth lens; l7-seventh lens; l8-eighth lens; l9-ninth lens; l10-tenth lens; l11-eleventh lens.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, a mid-focus video lens having a focal length of 65mm includes, in order from an object side to an image side, a first lens group G1, an iris STO, and a second lens group G2;
the first lens group G1 has positive power and is movable in position in the optical axis direction;
the second lens group G2 has positive power and is movable in position in the optical axis direction;
the first lens group G1 includes a first positive lens group G11 and a first negative lens group G12, the first positive lens group G11 includes at least one positive lens and a negative positive cemented lens;
first negative lens group G12 includes at least one positive lens and at least one negative lens;
the second lens group G2 comprises at least one negative lens and two negative and positive cemented lenses;
the first lens group G1 and the second lens group G2 satisfy the following formula:
1<f1/f2<3；-0.5<f12/f1<-0.1；
where f1 represents the focal length value of the first lens group G1, f2 represents the focal length value of the second lens group G2, and f12 represents the focal length value of the first negative lens group G12.
Further, the positive lens of the first positive lens group G11 is the first lens L1 close to the object side, and the mirror surface of the first lens L1 is curved toward the object side.
Further, the negative lens of the second lens group G2 is a tenth lens L10 close to the image side, the tenth lens L10 is crescent-shaped, and the mirror surface of the tenth lens L10 is curved toward the image side.
To explain, the refractive index of the positive lens of the cemented lens in the first lens group G1 is between 1.4 and 1.5.
To explain, the refractive index of the positive lens of the two cemented lenses of the second lens group G2 is between 1.7 and 1.9.
In a further description, the abbe number difference of at least one of the cemented lenses in the second lens group G2 is between 10 and 20.
Further, the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 0.2< BFL/f < 1. The lens adopts a reverse long-distance light path structure, and can ensure enough rear working distance by meeting the relation that BFL/f is less than 1 and is 0.2.
Further, the total length of the first mirror surface to the last mirror surface of the lens is between 50 and 70 mm, and the maximum aperture of the lens is between 35 and 45 mm.
The working principle is as follows:
the camera lens can be applied to video shooting, has a focal length of 65mm, is small in size and light, can realize a large imaging surface, and has a large light-passing aperture and clear full-view image quality.
The lens comprises a first lens group G1 and a second lens group G2, wherein the first lens group G1 and the second lens group G2 can move along the optical axis direction, focusing and zooming are realized through the moving cooperation of the two lens groups, and the length of the lens can be reduced to a certain degree due to the fact that the first lens group G1 and the second lens group G2 can both move.
The first lens group G1 includes, in order from the object side to the image side, a first lens L1 with positive focal power, a second lens L2 with negative focal power, a third lens L3 with positive focal power, a fourth lens L4 with positive focal power, and a fifth lens L5 with negative focal power, where the first lens L1 to the third lens L3 constitute a first positive lens group G11, and the second lens L2 and the third lens L3 are cemented into a cemented lens, which facilitates correction of chromatic aberration. The mirror surface of the first lens L1 is curved toward the object side, and the angle of the field of view can be increased, the amount of light transmitted can be increased, the aperture can be reduced, and the resolution of the peripheral field of view can be improved.
The light path of the first lens group G1 is of a quasi-double-Gaussian structure, so that the total coma aberration can be reduced, the tolerance sensitivity of the front and rear lens groups can be reduced, and the correction of distortion and coma aberration is well performed.
The second lens group G2 includes, in order from the object side to the image side, a sixth lens L6 with negative focal power, a seventh lens L7 with positive focal power, an eighth lens L8 with negative focal power, a ninth lens L9 with positive focal power, and a tenth lens L10 with negative focal power, wherein the sixth lens L6 and the seventh lens L7 are cemented into a cemented lens, and the eighth lens L8 and the ninth lens L9 are cemented into a cemented lens, and the two cemented lenses can correct chromatic aberration and distortion, and the difference in abbe number of at least one cemented lens is set to be between 10 and 20, and preferably the difference in abbe number between the eighth lens L8 and the ninth lens L9 is 12, so that further correction of chromatic aberration can be achieved, and sharpness is improved; in order to reduce the dispersion, the abbe number of the two cemented lenses can be increased as much as possible, and the difference between the abbe numbers is between 10 and 20.
The tenth lens L10 is in a crescent shape, and the mirror surface of the second lens L2 is curved toward the image side, so that coma and astigmatism of the front and rear lens groups can be effectively balanced, the tolerance sensitivity of the front and rear lens groups is greatly reduced, and the imaging surface is also increased.
The refractive indexes of some lenses of the second lens group G2 can be set between 1.7 and 1.9, and preferably, the seventh lens L7 and the ninth lens L9 are provided with high refractive index lenses, so that the incident light with a wide angle can be effectively bent, when the light with a large angle enters the system stop, the maximum deflection angle is less than 25 °, and simultaneously, the total length of the optical path can be effectively shortened and the number of lenses can be reduced.
The abbe number of some lens of the lens can be properly increased, which is favorable for reducing dispersion.
A planar eleventh lens L11 is disposed close to the image side of the lens.
Referring now to Table one, numerical data for some embodiments, such as radius of curvature, thickness, refractive index, Abbe number, etc. of the lens are shown, where S1-S18 represent the mirror surface of the lens from the object side to the image side, and the numerical data are typically in "mm" units.
Table one:
fig. 2 is an on-axis spherical aberration diagram of the embodiment of the present disclosure, fig. 3 is a vertical axis chromatic aberration diagram of the embodiment of the present disclosure, fig. 4 is a field curvature distortion diagram of the embodiment of the present disclosure, fig. 5 is a light aberration diagram of the embodiment of the present disclosure, fig. 6 is a diffuse spot diagram of the embodiment of the present disclosure, fig. 7 is an MTF diagram of the embodiment of the present disclosure, and fig. 8 is an MTF and field diagram of the embodiment of the present disclosure.
The foregoing disclosure discloses only some embodiments of the invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept herein, and it is intended to cover all such modifications and variations as fall within the scope of the invention.
Claims (8)
1. The middle focus video lens with the focal length of 65mm is characterized by comprising a first lens group (G1), an iris diaphragm and a second lens group (G2) in sequence from an object side to an image side;
the first lens group (G1) has positive power and is movable in position in the optical axis direction;
the second lens group (G2) has positive power and is movable in position in the optical axis direction;
the first lens group (G1) comprises a first positive lens group (G11) and a first negative lens group (G12), the first positive lens group (G11) comprising at least one positive lens and a negative positive cemented lens;
the first negative lens group (G12) comprises at least one positive lens and at least one negative lens;
the second lens group (G2) comprises at least one negative lens and two negative positive cemented lenses;
the first lens group (G1) and the second lens group (G2) satisfy the following formula:
1<f1/f2<3；-0.5<f12/f1<-0.1；
wherein f1 represents a focal length value of the first lens group (G1), f2 represents a focal length value of the second lens group (G2), and f12 represents a focal length value of the first negative lens group (G12).
2. The mid-focus video lens with a focal length of 65mm as claimed in claim 1, wherein the positive lens of the first positive lens group (G11) is a first lens (L1) close to the object side, and the lens surface of the first lens (L1) is curved towards the object side.
3. The mid-focus video lens with a focal length of 65mm as claimed in claim 1, wherein the negative lens of the second lens group (G2) is a tenth lens (L10) close to the image side, the tenth lens (L10) is crescent-shaped, and the mirror surface of the tenth lens (L10) is curved to the image side.
4. The mid-focus video lens with 65mm focal length according to claim 1, wherein the refractive index of the positive lens of the cemented lens of the first lens group (G1) is between 1.4 and 1.5.
5. The mid-focus video lens with 65mm focal length according to claim 1, wherein the refractive index of the positive lens of the two cemented lenses of the second lens group (G2) is between 1.7 and 1.9.
6. The mid-focus video lens with 65mm focal length according to claim 1 or 5, wherein the abbe number difference of at least one cemented lens in the second lens group (G2) is between 10 and 20.
7. The mid-focus video lens with a focal length of 65mm as claimed in claim 1, wherein the back working distance of the lens is BFL, the focal length of the lens is f, and the following equation is satisfied: 0.2< BFL/f < 1.
8. The mid-focus video lens with a focal length of 65mm as claimed in claim 1, wherein the total length of the first mirror to the last mirror of the lens is between 50 and 70 mm, and the maximum aperture of the lens is between 35 and 45 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010686101.4A CN111694129A (en) | 2020-07-16 | 2020-07-16 | Middle focus video lens with 65mm focal length |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010686101.4A CN111694129A (en) | 2020-07-16 | 2020-07-16 | Middle focus video lens with 65mm focal length |
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| CN111694129A true CN111694129A (en) | 2020-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010686101.4A Pending CN111694129A (en) | 2020-07-16 | 2020-07-16 | Middle focus video lens with 65mm focal length |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115079387A (en) * | 2022-06-01 | 2022-09-20 | 广东北创光电科技股份有限公司 | Medium-focus long flange video lens |
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2020
- 2020-07-16 CN CN202010686101.4A patent/CN111694129A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115079387A (en) * | 2022-06-01 | 2022-09-20 | 广东北创光电科技股份有限公司 | Medium-focus long flange video lens |
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