CN111694130B - Long-focus video lens with focal length of 85mm - Google Patents
Long-focus video lens with focal length of 85mm Download PDFInfo
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- CN111694130B CN111694130B CN202010686129.8A CN202010686129A CN111694130B CN 111694130 B CN111694130 B CN 111694130B CN 202010686129 A CN202010686129 A CN 202010686129A CN 111694130 B CN111694130 B CN 111694130B
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- 238000003384 imaging method Methods 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 12
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- 206010010071 Coma Diseases 0.000 description 3
- 201000009310 astigmatism Diseases 0.000 description 3
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- 206010073261 Ovarian theca cell tumour Diseases 0.000 description 2
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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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Abstract
The invention discloses a long Jiao Shipin lens with a focal length of 85mm, 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 second lens group has positive focal power, 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 negative positive cemented lens, the first negative lens group comprises at least one positive cemented lens and at least one negative cemented lens, the second lens group comprises a second negative lens group, the second negative lens group comprises at least one negative positive cemented lens, and the first lens group and the second lens group are respectively provided with cemented lenses, so that chromatic aberration and distortion can be corrected, and imaging definition can be improved.
Description
Technical Field
The invention relates to the technical field of lenses, in particular to a long-focus video lens with a focal length of 85 mm.
Background
With the development of the short video field, the video lens is increasingly applied to the short video shooting field, and the equipment has small requirement volume, low distortion and clear full field of view, so that the market share is gradually improved every year, but the definition of the existing lens is not high.
Disclosure of Invention
The invention aims to provide a long Jiao Shipin lens with a focal length of 85mm, wherein the first lens group and the second lens group are respectively provided with a cemented lens, so that chromatic aberration and distortion can be corrected, imaging definition is improved, and the problem of low imaging definition of the existing lens is solved.
To achieve the purpose, the invention adopts the following technical scheme:
a long Jiao Shipin lens with a focal length of 85mm 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 is fixed in position;
the second lens group has positive focal power and the position 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 negative positive cemented lens, and the first negative lens group comprises at least one positive negative cemented lens;
The second lens group comprises a second negative lens group, and the second negative lens group comprises at least one negative positive cemented lens;
the first lens group and the second lens group satisfy the following formula:
1＜f1/f2＜3；－0.5＜f12/f1＜－0.1；－6＜f21/f2＜－3；
Wherein f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, f12 represents the focal length of the first negative lens group, and f21 represents the focal length of the second negative lens group.
Therefore, the focal power of the first lens group and the second lens group meets the relation of the corresponding values of 1 < f1/f2 < 3, so that the enough back working distance can be ensured, and the practical application is met; the focal power of the first negative lens group and the first lens group meets the ratio relation of-0.5 < f12/f1 < -0.1, can ensure the view field angle born by the system and is beneficial to the phase difference correction of the full view field; the first lens group and the second lens group have positive focal power, can better change the magnification, are provided with a cemented lens, can correct chromatic aberration and distortion, and improve the image quality definition of the full view field.
In some embodiments, the second lens group further comprises a crescent-shaped negative optic.
Therefore, the crescent negative lens is a ninth lens, so that the coma aberration and astigmatism of the front lens group and the rear lens group can be effectively balanced, and the tolerance sensitivity of the front lens group and the rear lens group is greatly reduced.
In some embodiments, the negative lens is disposed near the image side, and the mirror surface of the negative lens curves toward the object side.
Thus, the imaging surface can be increased by bending the mirror surface of the ninth lens to the object side.
In some embodiments, the first positive lens group further comprises a positive lens disposed proximate the object side, the mirror surface of the positive lens curving toward the object side.
Thus, the positive lens is a first lens, and bending of the lens surface to the object side can increase the viewing angle, improve the light flux, and reduce the aperture.
In some embodiments, the rear working distance of the lens is BFL, the focal length of the lens is f, and the following formula is satisfied: BFL/f is more than 0.1 and less than 0.5.
This relationship can thus ensure a sufficient post-working distance.
In some embodiments, the refractive index of at least one of the cemented lenses of the first positive lens group is between 1.75 and 1.85;
the refractive index of at least one of the cemented lenses of the first negative lens group is between 1.75 and 1.85.
The cemented lens of the first positive lens is composed of a second lens and a third lens, and the refractive index of the second lens and/or the third lens is/are arranged between 1.75 and 1.85; the cemented lens of the first negative lens group is composed of a fourth lens and a fifth lens, and the refractive index of the fourth lens and/or the fifth lens is set between 1.75 and 1.85. Proper placement of the higher refractive index lens can reduce the lens volume.
In some embodiments, the refractive index of at least one of the cemented lenses of the second negative lens group is between 1.75 and 1.85.
Thus, the cemented lens of the second negative lens group is composed of a sixth lens and a seventh lens, and the refractive index of the sixth lens and/or the seventh lens is set to be between 1.75 and 1.85. Proper placement of the higher refractive index lens can reduce the lens volume.
In some embodiments, the first lens group has at least one cemented lens having an abbe number difference between 30 and 40.
Thereby, the difference in Abbe number between 30 and 40 between the cemented lenses of the first positive lens group and/or the cemented lenses of the first negative lens group, the larger Abbe number difference enabling chromatic aberration correction, preferably the Abbe number difference of the cemented lenses of the first negative lens group is 35.
In some embodiments, the total length of the first mirror to the last mirror of the lens is between 70 and 90 mm, and the maximum aperture of the lens is between 45 and 50 mm.
The invention has the beneficial effects that: the first lens group is provided with two cemented lenses, and the difference value of Abbe numbers of at least one cemented lens is between 30 and 40, so that chromatic aberration and distortion can be effectively corrected, and imaging definition is improved;
And the second lens group is provided with a crescent ninth lens, so that the coma aberration and astigmatism of the front lens group and the rear lens group can be effectively balanced, and the tolerance sensitivity of the front lens group and the rear lens group is greatly reduced.
Drawings
FIG. 1 is a block diagram of a 85mm focal length tele video lens of the present invention;
FIG. 2 is a schematic diagram of an on-axis chromatic aberration of a 85mm focal length tele video lens according to the present invention;
FIG. 3 is a schematic diagram of chromatic aberration of a tele video lens with a focal length of 85 mm;
FIG. 4 is a schematic diagram of field curvature distortion of a 85mm focal length tele video lens according to the present invention;
FIG. 5 is a schematic view of aberration of a 85mm focal length tele video lens according to the present invention;
FIG. 6 is a schematic view of a diffuse speckle of a 85mm focal length tele video lens of the present invention;
FIG. 7 is a schematic view of MTF of a 85mm focal length tele video lens of the present invention;
FIG. 8 is a schematic view of MTF and field of view of a 85mm focal length tele video lens of the present invention;
Wherein: g1-a first lens group; g11-a first positive lens group; g12—a first negative lens group; g2—a second lens group; g21—a second negative lens group; l1-a first lens; l2-a second lens; l3-a third lens; l4-fourth lens; l5-a fifth lens; l6-sixth lens; l7-seventh lens; l8-eighth lens; l9-a ninth lens; l10-tenth lens.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings.
Referring to fig. 1, a long Jiao Shipin lens with a focal length of 85mm includes, in order from an object side to an image side, a first lens group G1, an iris stop and a second lens group G2;
The first lens group G1 has positive focal power and is fixed in position;
The second lens group G2 has positive optical power and the position is movable along 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 including at least one negative positive cemented lens, the first negative lens group G12 including at least one positive negative cemented lens;
The second lens group G2 includes a second negative lens group G21, and the second negative lens group G21 includes at least one negative positive cemented lens;
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；－6＜f21/f2＜－3；
wherein f1 represents the focal length of the first lens group G1, f2 represents the focal length of the second lens group G2, f12 represents the focal length of the first negative lens group G12, and f21 represents the focal length of the second negative lens group G21.
Further illustratively, the second lens group G2 further includes a crescent-shaped negative optic.
Further, the negative lens is disposed near the image side, and the mirror surface of the negative lens is curved toward the image side.
Further, the first positive lens group G11 further includes a positive lens disposed near the object side, and a mirror surface of the positive lens is curved toward the object side.
Further describing, the rear working distance of the lens is BFL, the focal length of the lens is f, and the following formula is satisfied: BFL/f is more than 0.1 and less than 0.5.
Further illustratively, the refractive index of at least one of the cemented lenses of the first positive lens group G11 is between 1.75 and 1.85;
The refractive index of at least one of the cemented lenses of the first negative lens group G12 is between 1.75 and 1.85.
Further illustratively, at least one of the cemented lenses of the second negative lens group G21 has a refractive index of between 1.75 and 1.85.
Further, the first lens group G1 has at least one cemented lens with an abbe number difference between 30 and 40.
Further, the total length of the first mirror surface to the last mirror surface of the lens is between 70 and 90 mm, and the maximum caliber of the lens is between 45 and 50 mm.
Working principle:
The lens can be applied to video shooting, has a focal length of 85mm, the first lens group G1 is fixed, and the second lens group G2 can move.
The first lens group G1 sequentially comprises 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 from the object side to the image side, wherein the first lens L1, the second lens L2 and the third lens L3 form a first positive lens group G11, the mirror surface of the first lens L1 is bent towards the object side and is crescent, the view field angle can be increased, the light flux is improved, the second lens L2 and the third lens L3 are glued into a glued lens, the fourth lens L4 and the fifth lens L5 are glued into a glued lens, and the two glued lenses can be matched to correct chromatic aberration and distortion.
The optical path of the first lens group G1 is in a double-Gaussian structure, so that the total coma aberration is smaller, the tolerance sensitivity of the front lens group and the rear lens group can be reduced, and the symmetrical structure has good effect on correcting distortion and coma aberration.
The larger difference between the differences 30-40 in abbe numbers of at least one of the cemented lenses in the first lens group G1 can further correct chromatic aberration and distortion. The Abbe number of each lens can be properly increased while the Abbe number difference value is ensured, thereby being beneficial to reducing chromatic dispersion.
Some lenses of the first lens group G1 are appropriately arranged to have a higher refractive index, for example, the refractive index of the third lens L3 and the fourth lens L4 is set between 1.75 and 1.85, and other lenses may be arranged, so that the volume size of the lens can be reduced, and the lens is lighter.
The second lens group G2 sequentially comprises a sixth lens L6 with negative optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with positive optical power and a ninth lens L9 with negative optical power from the object side to the image side, wherein the sixth lens L6 and the seventh lens L7 form a cemented lens, and the cemented lens can correct color and distortion as a second negative lens group G21; the ninth lens L9 is a crescent negative lens, and the mirror surface of the ninth lens L9 is bent towards the object side, so that coma aberration and astigmatism of the front lens group and the rear lens group can be effectively balanced, the tolerance sensitivity of the front lens group and the rear lens group is greatly reduced, and the imaging surface can be increased.
The lens is further provided with a planar tenth lens L10 near the image side.
Referring now to Table one, numerical data for certain embodiments, such as radius of curvature, thickness, refractive index, and abbe number of the lens, are shown, where S1-S16 represent the mirror surface of the lens from the object side to the image side in that order, numerical data and the like are typically used in "mm".
Table one:
fig. 2 is an on-axis spherical aberration diagram of an embodiment of the present disclosure, fig. 3 is a vertical chromatic aberration diagram of an embodiment of the present disclosure, and fig. 4 is a field curvature distortion diagram of an embodiment of the present disclosure. Fig. 5 is a light aberration diagram of an embodiment of the disclosure, fig. 6 is a diffuse speckle diagram of an embodiment of the disclosure, fig. 7 is an MTF diagram of an embodiment of the disclosure, and fig. 8 is an MTF diagram and a view diagram of an embodiment of the disclosure.
What has been disclosed above is but a few embodiments of the present invention. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the invention.
Claims (9)
1. A long Jiao Shipin lens with a focal length of 85mm, which is characterized by comprising a first lens group (G1), an iris diaphragm and a second lens group (G2) from an object side to an image side in sequence;
the first lens group (G1) has positive optical power;
The second lens group (G2) has positive optical power;
the number of lens groups of the lens with focal power is two;
the first lens group (G1) consists of 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, wherein the first lens (L1), the second lens (L2) and the third lens (L3) form a first positive lens group (G11), and the second lens (L2) and the third lens (L3) are glued to form a glued lens; the fourth lens (L4) and the fifth lens (L5) form a first negative lens group (G12), and the fourth lens (L4) and the fifth lens (L5) are glued into a glued lens;
the second lens group (G2) is composed of a sixth lens (L6) with negative focal power, a seventh lens (L7) with positive focal power, an eighth lens (L8) with positive focal power and a ninth lens (L9) with negative focal power, wherein the sixth lens (L6) and the seventh lens (L7) form a second negative lens group (G21), and the sixth lens (L6) and the seventh lens (L7) are glued into a glued lens;
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；－6＜f21/f2＜－3；
Wherein f1 represents the focal length value of the first lens group (G1), f2 represents the focal length value of the second lens group (G2), f12 represents the focal length value of the first negative lens group (G12), and f21 represents the focal length value of the second negative lens group (G21).
2. A long Jiao Shipin lens with a focal length of 85mm according to claim 1, characterised in that the ninth lens (L9) is a crescent-shaped negative lens.
3. A long Jiao Shipin lens with a focal length of 85mm according to claim 2, characterised in that the ninth lens (L9) is arranged close to the image side and the mirror surface of the ninth lens (L9) is curved towards the object side.
4. A long Jiao Shipin lens with a focal length of 85mm according to claim 1, wherein the first lens (L1) is arranged close to the object side, and the mirror surface of the first lens (L1) is curved towards the object side and is crescent-shaped.
5. A lens of length Jiao Shipin with a focal length of 85mm according to claim 1, wherein the back working distance of the lens is BFL and the focal length of the lens is f, satisfying the following formula: BFL/f is more than 0.1 and less than 0.5.
6. A lens of length Jiao Shipin with a focal length of 85mm according to claim 1, characterized in that the refractive index of at least one of the cemented lenses of the first positive lens group (G11) is between 1.75 and 1.85;
the refractive index of at least one of the cemented lenses of the first negative lens group (G12) is between 1.75 and 1.85.
7. A lens of length Jiao Shipin with a focal length of 85mm according to claim 1, characterized in that the refractive index of at least one of the cemented lenses of the second negative lens group (G21) is between 1.75 and 1.85.
8. A lens of length Jiao Shipin with a focal length of 85mm according to claim 1, characterized in that the first lens group (G1) has at least one cemented lens with an abbe number difference between 30 and 40.
9. A lens of length Jiao Shipin as claimed in claim 1, wherein the total length of the first to last mirror of the lens is between 70 and 90 mm and the maximum aperture of the lens is between 45 and 50 mm.
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| CN202010686129.8A CN111694130B (en) | 2020-07-16 | 2020-07-16 | Long-focus video lens with focal length of 85mm |
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| CN202010686129.8A CN111694130B (en) | 2020-07-16 | 2020-07-16 | Long-focus video lens with focal length of 85mm |
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| CN111694130B true CN111694130B (en) | 2024-05-31 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112083557B (en) * | 2020-10-15 | 2025-06-13 | 舜宇光学(中山)有限公司 | Fixed focus lens and imaging system |
| CN112305714B (en) * | 2020-10-22 | 2025-07-15 | 舜宇光学(中山)有限公司 | Imaging Lenses |
| 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 |
| CN116582738B (en) * | 2023-07-13 | 2023-10-27 | 珠海市川富光学技术有限公司 | Long-focus large-aperture short-flange video lens with focal length of 85mm |
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