Large aperture inner focusing telephoto lens

Abstract

The present application discloses a large aperture internal focusing telephoto camera lens. The camera lens comprises, from the object side to the image side, a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with negative focal power; during the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the positions of the first lens group and the fourth lens group relative to the image plane remain unchanged; the large aperture internal focusing telephoto camera lens satisfies the following conditions: 0≤F1 / F≤2, (1); ‑2≤F2 / F≤0, (2); 0≤F3 / F≤2.5, (3); ‑6≤F4 / F≤0, (4). The technical solution of the present application can reduce aberrations, field curvature and distortion by setting the positive and negative focal powers of each lens group, the ratio between the composite focal length of each lens group and the composite focal length of the entire lens, and a unique focusing mechanism, thereby improving the imaging quality.

Description

Technical Field

[0001] The present application relates to the field of camera technology, and in particular to a large aperture internal focusing telephoto camera lens. Background Art

[0002] In the field of photography, image quality is a common goal pursued by photographers and lens manufacturers. Large aperture telephoto lenses can not only provide sufficient light intake in low-light environments, but also capture delicate images at a distance through their telephoto characteristics, while achieving excellent background blur effects through large apertures, thereby improving overall image quality. Therefore, due to its unique advantages, they have gradually become a regular choice for photographers.

[0003] However, traditional telephoto lenses often face the problem of reduced optical performance and impaired image quality when pursuing high magnification zoom. How to optimize the lens structure to achieve a higher imaging effect is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] The present application provides a large aperture inner focusing telephoto photography lens, aiming to solve the problem that the existing large aperture inner focusing telephoto photography lens cannot achieve a relatively excellent imaging effect.

[0005] To achieve the above-mentioned purpose, the present application proposes a large aperture internal focusing telephoto photography lens. The large aperture internal focusing telephoto photography lens comprises, from the object side to the image side, a first lens group with positive optical power, a second lens group with negative optical power, an aperture stop, a third lens group with positive optical power, and a fourth lens group with negative optical power; during the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the first lens group and the fourth lens group remain unchanged relative to the image plane;

[0006] A large aperture internal focusing telephoto lens meets the following conditions:

[0007] 0≤F1 / F≤2, (1);

[0008] -2≤F2 / F≤0, (2);

[0009] 0≤F3 / F≤2.5, (3);

[0010] -6≤F4 / F≤0, (4);

[0011] Among them, F1 represents the composite focal length of the first lens group, F2 represents the composite focal length of the second lens group, F3 represents the composite focal length of the third lens group, F4 represents the composite focal length of the fourth lens group, and F represents the composite focal length of the photographic lens.

[0012] In some embodiments, the first lens group includes at least three lenses with an Abbe number Vd ≥ 60, two lenses with a refractive index Nd ≥ 1.8, and a group of cemented lenses;

[0013] The refractive index Nd of the lens adjacent to the object side in the first lens group is ≥1.8, the cemented lens is composed of positive and negative optical power lenses, and the Abbe number Vd of the lens with positive optical power in the cemented lens is ≥60.

[0014] In some embodiments, the first lens group includes, from the object side to the image side, a first lens with positive power, a second lens with positive power, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power, a sixth lens with positive power and a seventh lens with negative power; wherein the fourth lens and the fifth lens are combined into a first cemented lens with positive power; the sixth lens and the seventh lens are combined into a second cemented lens with positive power; the refractive index Nd of the first lens, the fifth lens and the seventh lens is ≥1.8; the Abbe number Vd of the second lens, the third lens, the fourth lens and the sixth lens is ≥60; or,

[0015] The first lens group includes, from the object side to the image side, a first lens with positive power, a second lens with positive power, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power, and a sixth lens with positive power;

[0016] The fourth lens and the fifth lens are combined into a first cemented lens with positive power; the sixth lens is an aspherical lens; the refractive index Nd of the first lens and the fifth lens is ≥1.8; and the Abbe number Vd of the second lens, the third lens and the fourth lens is ≥60.

[0017] In some embodiments, the second lens group includes at least one lens with negative optical power.

[0018] In some embodiments, the second lens group is an eighth lens having negative optical power; or,

[0019] The second lens group includes, from the object side to the image side, an eighth lens having negative refractive power and a ninth lens having negative refractive power.

[0020] In some embodiments, the third lens group is composed of a cemented lens and a lens with positive optical power from the object side to the image side;

[0021] The cemented lens is composed of a lens with negative optical power and a lens with positive optical power, and the surface of the lens of the cemented lens adjacent to the aperture stop is bent toward the aperture stop.

[0022] In some embodiments, the third lens group includes, from the object side to the image side, a tenth lens having negative power, an eleventh lens having positive power, and a twelfth lens having positive power;

[0023] The tenth lens and the eleventh lens are combined into a third cemented lens with negative optical power.

[0024] In some embodiments, the refractive index Vd11 of the eleventh lens is ≥1.8, and the twelfth lens is an aspherical lens.

[0025] In some embodiments, the fourth lens group includes at least two groups of cemented lenses, and the last lens of the fourth lens group adjacent to the image side is a lens with negative optical power that is bent toward the object side;

[0026] The shape of the cemented lens close to the object side is a meniscus, and the surface close to the image side is curved toward the image side.

[0027] In some embodiments, the fourth lens group includes, from the object side to the image side, a thirteenth lens with positive power, a fourteenth lens with negative power, a fifteenth lens with positive power, a sixteenth lens with negative power, a seventeenth lens with positive power, an eighteenth lens with negative power, and a nineteenth lens with negative power; wherein the thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative power; the fifteenth lens, the sixteenth lens, and the seventeenth lens are combined into a fifth cemented lens with positive power; or,

[0028] The fourth lens group includes, from the object side to the image side, a thirteenth lens with positive power, a fourteenth lens with negative power, a fifteenth lens with positive power, a sixteenth lens with negative power, a seventeenth lens with positive power, an eighteenth lens with negative power and a nineteenth lens with negative power; wherein the thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative power; the fourteenth lens and the fifteenth lens are combined into a sixth cemented lens with negative power; the sixteenth lens and the seventeenth lens are combined into a seventh cemented lens with positive power; or,

[0029] The fourth lens group includes, from the object side to the image side, a thirteenth lens having positive power, a fourteenth lens having negative power, a fifteenth lens having positive power, a sixteenth lens having negative power, and a seventeenth lens having negative power;

[0030] The thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative optical power; the fifteenth lens and the sixteenth lens are combined into an eighth cemented lens with negative optical power.

[0031] The technical solution of the present application proposes a large aperture inner focusing telephoto camera lens. The large aperture inner focusing telephoto camera lens comprises, from the object side to the image side, a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with negative focal power; during the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the positions of the first lens group and the fourth lens group relative to the image plane remain unchanged; the large aperture inner focusing telephoto camera lens satisfies the following conditions: 0≤F1 / F≤2, (1); -2≤F2 / F≤0, (2); 0≤F3 / F≤2.5, (3); -6≤F4 / F≤0, (4). The technical solution of the present application optimizes the refraction and convergence of light, reduces aberrations and distortions, and thus improves the imaging quality by setting the positive and negative focal powers of each lens group and the ratio between the composite focal length of each lens group and the composite focal length of the entire lens. At the same time, during the focusing process, the second lens group moves along the optical axis toward the image side, and the third lens group moves along the optical axis toward the object side. The use of a dual floating focusing structure can effectively deal with the field curvature introduced during close-end focusing, further enabling the lens to achieve higher image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0033] Figure 1 A schematic diagram showing the structure of Embodiment 1 of the present invention is shown;

[0034] Figure 2 A schematic diagram showing spherical aberration of Embodiment 1 of the present invention when in focus at infinity is shown;

[0035] Figure 3 A schematic diagram showing field curvature and distortion of embodiment 1 of the present invention when focusing at infinity is shown;

[0036] Figure 4 A schematic diagram showing spherical aberration of Embodiment 1 of the present invention at the minimum focusing distance is shown;

[0037] Figure 5A schematic diagram showing field curvature and distortion of Embodiment 1 of the present invention at the closest focusing distance is shown;

[0038] Figure 6 A schematic diagram showing the structure of Embodiment 2 of the present invention is shown;

[0039] Figure 7 A schematic diagram showing spherical aberration of Embodiment 2 of the present invention when in focus at infinity;

[0040] Figure 8 A schematic diagram showing field curvature and distortion of Embodiment 2 of the present invention when focusing at infinity;

[0041] Fig. 9 A schematic diagram showing spherical aberration of Embodiment 2 of the present invention at the closest focusing distance is shown;

[0042] Fig.10 A schematic diagram showing field curvature and distortion of Embodiment 2 of the present invention at the closest focusing distance is shown;

[0043] Fig.11 A schematic diagram showing the structure of Embodiment 3 of the present invention is shown;

[0044] Fig.12 A schematic diagram showing spherical aberration of Embodiment 3 of the present invention when in focus at infinity is shown;

[0045] Fig.13 A schematic diagram showing field curvature and distortion of embodiment 3 of the present invention when in focus at infinity is shown;

[0046] Fig.14 A schematic diagram showing spherical aberration of Embodiment 3 of the present invention at the closest focusing distance is shown;

[0047] Fig.15 A schematic diagram showing field curvature and distortion of embodiment 3 of the present invention at the closest focusing distance is shown. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] See also Figure 1As shown, the present application proposes a large aperture inner focusing telephoto photography lens. The large aperture inner focusing telephoto photography lens comprises, from the object side to the image side, a first lens group G1 with positive focal power, a second lens group G2 with negative focal power, an aperture stop STP, a third lens group G3 with positive focal power, and a fourth lens group G4 with negative focal power; during the focusing process, the second lens group G2 moves along the optical axis toward the image side, the third lens group G3 moves along the optical axis toward the object side, and the first lens group G1 and the fourth lens group G4 remain unchanged relative to the image plane;

[0050] A large aperture internal focusing telephoto lens meets the following conditions:

[0051] 0≤F1 / F≤2, (1);

[0052] -2≤F2 / F≤0, (2);

[0053] 0≤F3 / F≤2.5, (3);

[0054] -6≤F4 / F≤0, (4);

[0055] Among them, F1 represents the composite focal length of the first lens group G1, F2 represents the composite focal length of the second lens group G2, F3 represents the composite focal length of the third lens group G3, F4 represents the composite focal length of the fourth lens group G4, and F represents the composite focal length of the photographic lens.

[0056] The technical solution of the present application achieves the purpose of optimizing the refraction and convergence of light, reducing aberrations and distortions, and improving the image quality by setting the positive and negative focal powers of each lens group and the ratio between the synthetic focal length of each lens group and the synthetic focal length of the entire lens. In the focusing process of the photographic lens of the present application, the second lens group G2 moves along the optical axis toward the image side, and the third lens group G3 moves along the optical axis toward the object side. The use of a double floating focus structure can effectively deal with the field curvature introduced during the near-end focusing process, further enabling the lens to achieve higher image quality.

[0057] In addition, by moving the second lens group G2 toward the image side and the third lens group G3 toward the object side, the focal position of the lens can be quickly adjusted to achieve a fast focus response.

[0058] In some embodiments, the first lens group G1 includes at least three lenses with an Abbe number Vd ≥ 60, two lenses with a refractive index Nd ≥ 1.8, and a group of cemented lenses; wherein the refractive index Nd ≥ 1.8 of the lens adjacent to the object side in the first lens group G1, the cemented lens is composed of positive and negative optical power lenses, and the Abbe number Vd ≥ 60 of the lens with positive optical power in the cemented lens.

[0059] The Abbe number is an indicator of the dispersion ability of a lens. The higher the Abbe number, the smaller the dispersion and the better the color reproduction of the image. In this embodiment, at least three lenses with an Abbe number Vd ≥ 60 are arranged in the first lens group G1, which can effectively reduce chromatic aberration and improve the clarity and color accuracy of the image.

[0060] At least two lenses with a refractive index Nd≥1.8 are also provided in the first lens group G1. In particular, the refractive index Nd≥1.8 of the first lens on the object side of the first lens group G1 can more effectively converge light and improve the luminous flux of the lens. At the same time, while keeping the lens size compact, aberrations and distortions are reduced to improve imaging quality.

[0061] In addition, a cemented lens is provided in the first lens group G1, and the cemented lens is composed of positive and negative optical power lenses, which can effectively correct lens aberrations, such as spherical aberration, coma, etc., thereby improving the sharpness and contrast of imaging. Moreover, the Abbe number Vd of the lens with positive optical power in the cemented lens is ≥60, which can further reduce dispersion and optimize imaging color.

[0062] Therefore, the above design of the first lens group G1 in this embodiment can not only improve the imaging quality, but also make the lens structure more compact and reduce the size of the lens.

[0063] In some embodiments, the first lens group G1 includes, from the object side to the image side, a first lens L01 with positive power, a second lens L02 with positive power, a third lens L03 with positive power, a fourth lens L04 with positive power, a fifth lens L05 with negative power, a sixth lens L06 with positive power, and a seventh lens L07 with negative power; wherein the fourth lens L04 and the fifth lens L05 are combined into a first cemented lens with positive power; the sixth lens L06 and the seventh lens L07 are combined into a second cemented lens with positive power; the refractive index Nd of the first lens L01, the fifth lens L05, and the seventh lens L07 is ≥1.8; and the Abbe number Vd of the second lens L02, the third lens L03, the fourth lens L04, and the sixth lens L06 is ≥60.

[0064] In this embodiment, a specific lens configuration of the first lens group G1 is proposed. The first lens group G1 is composed of seven lenses. Under the synergistic effect of the above-mentioned high Abbe number lens, high refractive index lens and cemented lens, a higher imaging effect can be achieved. Further, the fourth lens L04 and the fifth lens L05 satisfy the following conditional formula:

[0065] |Vd4-Vd5|≥30, (5);

[0066] Wherein, Vd4 is the Abbe number of the fourth lens L04 in the first lens group G1 with respect to the light with a wavelength of 587.6nm; Vd5 is the Abbe number of the fifth lens L05 in the first lens group G1 with respect to the light with a wavelength of 587.6nm. Thus, the difference (absolute value) of the Abbe numbers between the fourth lens L04 and the fifth lens L05 is required to be greater than or equal to 30. And, the sixth lens L06 and the seventh lens L07 satisfy the following conditional formula:

[0067] |Vd6-Vd7|≥30, (6);

[0068] Wherein, Vd6 is the Abbe number of the sixth lens L06 in the first lens group G1 with respect to the light with a wavelength of 587.6 nm; Vd7 is the Abbe number of the seventh lens L07 in the first lens group G1 with respect to the light with a wavelength of 587.6 nm. It is also required that the difference (absolute value) between the Abbe numbers of the sixth lens L06 and the seventh lens L07 is greater than or equal to 30.

[0069] The above-mentioned combination of high and low Abbe number lenses in the cemented lens can effectively correct the axial chromatic aberration in the lens. And by using the dispersion characteristics of different lens materials to complement each other, by selecting the appropriate lens material combination, the focal length change of the entire lens system under different color lights can be optimized, thereby reducing dispersion and improving image quality.

[0070] In some embodiments, the first lens group G1 includes, from the object side to the image side, a first lens L01 with positive power, a second lens L02 with positive power, a third lens L03 with positive power, a fourth lens L04 with positive power, a fifth lens L05 with negative power, and a sixth lens L06 with positive power; wherein the fourth lens L04 and the fifth lens L05 are combined into a first cemented lens with positive power; the sixth lens L06 is an aspherical lens; the refractive index Nd of the first lens L01 and the fifth lens L05 is ≥1.8; and the Abbe number Vd of the second lens L02, the third lens L03, and the fourth lens L04 is ≥60.

[0071] In this embodiment, another specific lens configuration of the first lens group G1 is proposed. The first lens group G1 in this embodiment is composed of six lenses, and can also achieve better imaging effects through the synergistic effects of high Abbe number lenses, high refractive index lenses and cemented lenses.

[0072] In some embodiments, the second lens group G2 includes at least one lens with negative optical power.

[0073] The second lens group G2 is used as a zoom group. By changing the distance between the second lens group G2 and the front and rear lens groups, the focal length can be changed. In this embodiment, the second lens group G2 includes at least one lens with negative optical power, so that the second lens group G2 can correct aberrations (such as spherical aberration and coma) while achieving the zoom function to improve the imaging quality.

[0074] In some embodiments, the second lens group G2 is an eighth lens L08 with negative power; or, the second lens group G2 includes, from the object side to the image side, an eighth lens L08 with negative power and a ninth lens L09 with negative power.

[0075] Two specific lens configurations of the second lens group G2 are proposed above.

[0076] In the first lens configuration, the second lens group G2 consists of only one lens with negative optical power, which can not only correct aberrations to achieve focal length change, but also simplify the lens structure and reduce manufacturing costs and complexity.

[0077] In the second lens configuration, the second lens group G2 is composed of two lenses with negative optical power, which can further enhance the divergence effect of light. Although the structure is increased compared with the first lens configuration, it can more effectively improve the imaging quality.

[0078] In some embodiments, the third lens group G3 consists of a cemented lens and a lens with positive optical power in sequence from the object side to the image side; wherein the cemented lens consists of a lens with negative optical power and a lens with positive optical power, and the surface of the lens of the cemented lens adjacent to the aperture stop STP is bent toward the aperture stop STP.

[0079] In this embodiment, the third lens group G3 with positive power can compensate for the change in the image plane position caused by the movement of the second lens group G2. As described above, the cemented lens composed of positive and negative power lenses can reduce aberrations and improve the imaging quality. In particular, the surface of the lens adjacent to the aperture stop STP in the cemented lens is bent toward the aperture stop STP, which helps to control the power and distribution of light when passing through the aperture stop STP, further reducing aberrations.

[0080] In addition, a lens with positive refractive power is further arranged on the side of the cemented lens close to the image side in the third lens group G3. The lens with positive refractive power can further converge light and ensure a clear image.

[0081] In some embodiments, the third lens group G3 includes, from the object side to the image side, a tenth lens L10 having negative power, an eleventh lens L11 having positive power, and a twelfth lens L12 having positive power; wherein the tenth lens L10 and the eleventh lens L11 are combined into a third cemented lens having negative power.

[0082] In this embodiment, a specific lens configuration of the third lens group G3 is proposed. The third lens group G3 is composed of three lenses, and the tenth lens L10 and the eleventh lens L11 are combined into a third cemented lens with negative optical power to meet the configuration requirements of the third lens L03.

[0083] Furthermore, the refractive index Vd11 of the eleventh lens L11 is ≥ 1.8, and the twelfth lens L12 is an aspherical lens. By setting the eleventh lens L11 as a high refractive index lens and the twelfth lens L12 as an aspherical lens in the third lens group G3, the aberration can be more effectively reduced based on the characteristics of the high refractive index lens and the aspherical lens, the optical performance of the lens can be improved, and high-quality imaging can be achieved.

[0084] In some embodiments, the fourth lens group G4 includes at least two groups of cemented lenses, and the last lens element adjacent to the image side in the fourth lens group G4 is a lens with negative optical power that is bent toward the object side; wherein the shape of the cemented lens close to the object side is a meniscus shape, and the surface adjacent to the image side is bent toward the image side.

[0085] In this embodiment, the fourth lens group G4 includes at least two groups of cemented lenses, which can reduce and simplify the lens structure and also help correct chromatic aberration.

[0086] The last lens on the image side has negative power and is curved toward the object, which can further correct the aberration introduced by the previous lens group. The cemented lens on the object side is meniscus-shaped, and its surface on the image side is curved toward the image side, which can also correct aberrations and improve the imaging performance of the lens.

[0087] Therefore, the fourth lens group G4 provided in this embodiment has a strong aberration correction effect, and can adapt to different optical systems and shooting requirements, so that the telephoto photography lens has an excellent imaging effect.

[0088] In some embodiments, the fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power, a seventeenth lens L17 with positive power, an eighteenth lens L18 with negative power, and a nineteenth lens L19 with negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens with negative power; the fifteenth lens L15, the sixteenth lens L16, and the seventeenth lens L17 are combined into a fifth cemented lens with positive power.

[0089] Alternatively, in some embodiments, the fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power, a seventeenth lens L17 with positive power, an eighteenth lens L18 with negative power and a nineteenth lens L19 with negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens with negative power; the fourteenth lens L14 and the fifteenth lens L15 are combined into a sixth lens L06 and a lens with negative power; the sixteenth lens L16 and the seventeenth lens L17 are combined into a seventh cemented lens with positive power.

[0090] Alternatively, in some embodiments, the fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power, and a seventeenth lens L17 with negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens with negative power; and the fifteenth lens L15 and the sixteenth lens L16 are combined into an eighth cemented lens with negative power.

[0091] The three specific lens configurations of the fourth lens group G4 are proposed above, which are used to achieve precise aberration correction and high-quality imaging effects through specific lens combinations and arrangements.

[0092] In the present application, a parallel glass plate GL configured by a filter is arranged between the last lens of the fourth lens group G4 and the image plane IMG. The parallel glass plate GL is used to filter light to improve the image quality. Specifically, the parallel glass plate GL can absorb or reflect light of certain wavelengths to eliminate or reduce interference factors such as chromatic aberration and stray light, thereby improving the contrast and clarity of the image.

[0093] The following is a specific embodiment of a large aperture inner focusing telephoto camera lens.

[0094] Example 1

[0095] Figure 1 The structure diagram of the large aperture inner focusing telephoto lens of Example 1 is shown. Figure 1 As shown, in this embodiment, the first lens group G1 includes, from the object side to the image side, a first lens L01 with positive refractive power, a second lens L02 with positive refractive power, a third lens L03 with positive refractive power, a fourth lens L04 with positive refractive power, a fifth lens L05 with negative refractive power, a sixth lens L06 with positive refractive power, and a seventh lens L07 with negative refractive power; wherein the fourth lens L04 and the fifth lens L05 are combined into a first cemented lens with positive refractive power; the sixth lens L06 and The seventh lens L07 is combined into a second cemented lens with positive power; the refractive index Nd1 of the first lens L01 is 1.946, the refractive index Nd5 of the fifth lens L05 is 1.9229, and the refractive index Nd7 of the seventh lens L07 is 1.846; the Abbe number Vd2 of the second lens L02 is 94.523, the Abbe number Vd3 of the third lens L03 is 81.595, the Abbe number V4 of the fourth lens L04 is 81.595, and the Abbe number Vd6 of the sixth lens L06 is 68.346. The second lens group G2 is an eighth lens L08 with negative power. The third lens group G3 includes, from the object side to the image side, a tenth lens L10 with negative power, an eleventh lens L11 with positive power and a twelfth lens L12 with positive power; wherein the tenth lens L10 and the eleventh lens L11 are combined into a third cemented lens with negative power, the refractive index Vd11 of the eleventh lens L11 is 1.8707, and the twelfth lens L12 is an aspherical lens. The fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power, a seventeenth lens L17 with positive power, an eighteenth lens L18 with negative power and a nineteenth lens L19 with negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens with negative power; the fourteenth lens L14 and the fifteenth lens L15 are combined into a sixth cemented lens with negative power; the sixteenth lens L16 and the seventeenth lens L17 are combined into a seventh cemented lens with positive power.

[0096] In this embodiment, specific numerical data of the large aperture inner focusing telephoto photography lens are shown in Tables 1 to 3:

[0097] Table 1

[0098]

[0099] Table 2

[0100]

[0101] Table 3

[0102]

[0103] Figure 2 and Figure 3 The spherical aberration, field curvature and distortion curves of Example 1 when the image is in focus at infinity are shown. Figure 4 and Figure 5 The spherical aberration, field curvature and distortion curves of Example 1 when the lens is in focus at the closest distance are shown.

[0104] When the lens is in focus at infinity, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.28, where the F line, D line, and C line represent the spherical aberration at wavelengths of 486nm, 587nm, and 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 13.9°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 13.9°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view. When focusing at the closest distance, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.46, where the F line, D line, and C line represent the spherical aberration at a wavelength of 486nm, a wavelength of 587nm, and a wavelength of 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 11.3°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 11.3°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view.

[0105] As can be seen from Figures 2-5, the camera lens of this embodiment 1 has a good imaging effect.

[0106] Example 2

[0107] Figure 6 The structure diagram of the large aperture inner focusing telephoto lens of Example 2 is shown. Figure 6As shown, in this embodiment, the first lens group G1 includes, from the object side to the image side, a first lens L01 with positive power, a second lens L02 with positive power, a third lens L03 with positive power, a fourth lens L04 with positive power, a fifth lens L05 with negative power and a sixth lens L06 with positive power; wherein the fourth lens L04 and the fifth lens L05 are combined into a first cemented lens with positive power; the sixth lens L06 is an aspherical lens; the refractive index Nd1 of the first lens L01 is 1.946, the refractive index Nd5 of the fifth lens L05 is 1.9229; the Abbe number Vd2 of the second lens L02 is 94.523, the Abbe number Vd3 of the third lens L03 is 81.595, and the Abbe number Vd4 of the fourth lens L04 is 81.595. The second lens group G2 includes, from the object side to the image side, an eighth lens L08 having negative power and a ninth lens L09 having negative power. The third lens group G3 includes, from the object side to the image side, a tenth lens L10 having negative power, an eleventh lens L11 having positive power and a twelfth lens L12 having positive power; wherein the tenth lens L10 and the eleventh lens L11 are combined into a third cemented lens having negative power. The fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 with positive power, a fourteenth lens L14 with negative power, a fifteenth lens L15 with positive power, a sixteenth lens L16 with negative power, a seventeenth lens L17 with positive power, an eighteenth lens L18 with negative power and a nineteenth lens L19 with negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens with negative power; the fourteenth lens L14 and the fifteenth lens L15 are combined into a sixth lens L06 and a lens with negative power; the sixteenth lens L16 and the seventeenth lens L17 are combined into a seventh cemented lens with positive power.

[0108] In this embodiment, specific numerical data of the large aperture inner focusing telephoto photography lens are shown in Table 4 to Table 6:

[0109] Table 4

[0110]

[0111] Table 5

[0112]

[0113] Table 6

[0114]

[0115] Figure 7 and Figure 8The spherical aberration, field curvature and distortion curves of Example 2 when the image is in focus at infinity are shown. Fig. 9 and Fig.10 The spherical aberration, field curvature and distortion curves of Example 2 are shown when the image is in focus at the closest distance.

[0116] When the lens is in focus at infinity, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.28, where the F line, D line, and C line represent the spherical aberration at wavelengths of 486nm, 587nm, and 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 14°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 14°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view. When focusing at the closest distance, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.48, where the F line, D line, and C line represent the spherical aberration at a wavelength of 486nm, a wavelength of 587nm, and a wavelength of 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 11.2°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 11.2°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view.

[0117] As can be seen from Figures 7-10, the camera lens of this embodiment 2 has a good imaging effect.

[0118] Example 3

[0119] Fig.11 The structure diagram of the large aperture inner focusing telephoto lens of Example 3 is shown. Fig.11As shown, in this embodiment, the first lens group G1 includes, from the object side to the image side, a first lens L01 with positive power, a second lens L02 with positive power, a third lens L03 with positive power, a fourth lens L04 with positive power, a fifth lens L05 with negative power and a sixth lens L06 with positive power; wherein the fourth lens L04 and the fifth lens L05 are combined into a first cemented lens with positive power; the sixth lens L06 is an aspherical lens; the refractive index Nd1 of the first lens L01 is 1.946, the refractive index Nd5 of the fifth lens L05 is 1.9229; the Abbe number Vd2 of the second lens L02 is 94.523, the Abbe number Vd3 of the third lens L03 is 81.595, and the Abbe number Vd4 of the fourth lens L04 is 81.595. The second lens group G2 includes, from the object side to the image side, an eighth lens L08 having negative power and a ninth lens L09 having negative power. The third lens group G3 includes, from the object side to the image side, a tenth lens L10 having negative power, an eleventh lens L11 having positive power, and a twelfth lens L12 having positive power; wherein the tenth lens L10 and the eleventh lens L11 are combined into a third cemented lens having negative power. The fourth lens group G4 includes, from the object side to the image side, a thirteenth lens L13 having positive power, a fourteenth lens L14 having negative power, a fifteenth lens L15 having positive power, a sixteenth lens L16 having negative power, and a seventeenth lens L17 having negative power; wherein the thirteenth lens L13 and the fourteenth lens L14 are combined into a fourth cemented lens having negative power; and the fifteenth lens L15 and the sixteenth lens L16 are combined into an eighth cemented lens having negative power.

[0120] In this embodiment, specific numerical data of the large aperture inner focusing telephoto photography lens are shown in Table 7 to Table 9:

[0121] Table 7

[0122]

[0123] Table 8

[0124]

[0125] Table 9

[0126]

[0127] Fig.12 and Fig.13 The spherical aberration, field curvature and distortion curves of Example 3 when in infinity focus are shown. Fig.14 and Fig.15 The spherical aberration, field curvature and distortion curves of Example 3 are shown when the image is in focus at the closest distance.

[0128] When the lens is in focus at infinity, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.28, where the F line, D line, and C line represent the spherical aberration at wavelengths of 486nm, 587nm, and 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 14.2°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 14.2°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view. When focusing at the closest distance, the spherical aberration curve shows the spherical aberration curve when the aperture number is 1.46, where the F line, D line, and C line represent the spherical aberration at a wavelength of 486nm, a wavelength of 587nm, and a wavelength of 656nm, respectively. The horizontal axis represents the spherical aberration value, and the vertical axis represents the field of view. The field curvature curve shows the field curvature curve when the half field angle ω is 11.1°, where the dotted line S represents the value of the chief ray D line on the sagittal image plane, the solid line T represents the value of the chief ray D line on the meridional image plane, the horizontal axis represents the field curvature value, and the vertical axis represents the field of view; the distortion curve shows the distortion curve when the half field angle ω is 11.1°, where the horizontal axis represents the distortion value, and the vertical axis represents the field of view.

[0129] As can be seen from Figures 12-15, the camera lens in this embodiment 3 has a good imaging effect.

[0130] The above description is only a partial or preferred embodiment of the present application. Neither the text nor the drawings can limit the scope of protection of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the overall concept of the present application, or direct / indirect application in other related technical fields are included in the scope of protection of the present application.

Claims

1. A large aperture inner focusing telephoto photography lens, characterized in that: The lens comprises, from the object side to the image side, a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with negative focal power; the large aperture internal focusing telephoto lens has four lens groups with focal power, and in the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the first lens group and the fourth lens group remain unchanged relative to the image plane; The first lens group includes, from the object side to the image side, a first lens with positive power, a second lens with positive power, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power, a sixth lens with positive power and a seventh lens with negative power, and the first lens group has seven lenses; The second lens group is an eighth lens with negative power; the third lens group includes, from the object side to the image side, a tenth lens with negative power, an eleventh lens with positive power and a twelfth lens with positive power, and the third lens group has three lenses; the fourth lens group includes, from the object side to the image side, a thirteenth lens with positive power, a fourteenth lens with negative power, a fifteenth lens with positive power, a sixteenth lens with negative power, a seventeenth lens with positive power, an eighteenth lens with negative power and a nineteenth lens with negative power, and the fourth lens group has seven lenses; A large aperture internal focusing telephoto lens meets the following conditions: 0≤F1 / F≤2, (1); -2≤F2 / F≤0, (2); 0≤F3 / F≤2.5, (3); -6≤F4 / F≤0, (4); Among them, F1 represents the composite focal length of the first lens group, F2 represents the composite focal length of the second lens group, F3 represents the composite focal length of the third lens group, F4 represents the composite focal length of the fourth lens group, and F represents the composite focal length of the photographic lens.

2. The large aperture inner focusing telephoto lens according to claim 1, characterized in that: In the first lens group, the fourth lens and the fifth lens are combined into a first cemented lens with positive power; the sixth lens and the seventh lens are combined into a second cemented lens with positive power; the refractive index Nd of the first lens, the fifth lens and the seventh lens is ≥1.8; the Abbe number Vd of the second lens, the third lens, the fourth lens and the sixth lens is ≥60.

3. The large aperture inner focusing telephoto lens according to claim 1, characterized in that: In the third lens group, the tenth lens and the eleventh lens are combined to form a third cemented lens with negative optical power; the refractive index Vd11 of the eleventh lens is ≥1.8, and the twelfth lens is an aspherical lens.

4. The large aperture inner focusing telephoto lens according to claim 1, characterized in that: In the fourth lens group, the thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative power; the fifteenth lens, the sixteenth lens and the seventeenth lens are combined into a fifth cemented lens with positive power.

5. A large aperture inner focusing telephoto photography lens, characterized in that: The lens comprises, from the object side to the image side, a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with negative focal power; the large aperture internal focusing telephoto lens has four lens groups with focal power, and in the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the first lens group and the fourth lens group remain unchanged relative to the image plane; The first lens group includes, from the object side to the image side, a first lens with positive power, a second lens with positive power, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power and a sixth lens with positive power, and the first lens group has six lenses; The second lens group includes, from the object side to the image side, an eighth lens having negative refractive power and a ninth lens having negative refractive power, and the second lens group has two lenses; The third lens group includes, from the object side to the image side, a tenth lens with negative power, an eleventh lens with positive power, and a twelfth lens with positive power, and the number of lenses of the third lens group is three; the fourth lens group includes, from the object side to the image side, a thirteenth lens with positive power, a fourteenth lens with negative power, a fifteenth lens with positive power, a sixteenth lens with negative power, a seventeenth lens with positive power, an eighteenth lens with negative power, and a nineteenth lens with negative power, and the number of lenses of the fourth lens group is seven; the large aperture inner focusing telephoto lens satisfies the following conditional formula: 0≤F1 / F≤2, (1); -2≤F2 / F≤0, (2); 0≤F3 / F≤2.5, (3); -6≤F4 / F≤0, (4); Among them, F1 represents the composite focal length of the first lens group, F2 represents the composite focal length of the second lens group, F3 represents the composite focal length of the third lens group, F4 represents the composite focal length of the fourth lens group, and F represents the composite focal length of the photographic lens.

6. The large aperture inner focusing telephoto lens according to claim 5, characterized in that: In the first lens group, the fourth lens and the fifth lens are combined into a first cemented lens with positive power; the sixth lens is an aspherical lens; the refractive index Nd of the first lens and the fifth lens is ≥1.8; the Abbe number Vd of the second lens, the third lens and the fourth lens is ≥60; in the third lens group, the tenth lens and the eleventh lens are combined into a third cemented lens with negative power.

7. The large aperture inner focusing telephoto lens according to claim 5, characterized in that: In the fourth lens group, the thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative power; the fourteenth lens and the sixteenth lens are combined into a sixth cemented lens with negative power; The seventeenth lens and the eighteenth lens are combined into a seventh cemented lens having positive refractive power.

8. A large aperture inner focusing telephoto lens, characterized in that: The lens comprises, from the object side to the image side, a first lens group with positive focal power, a second lens group with negative focal power, an aperture stop, a third lens group with positive focal power, and a fourth lens group with negative focal power; the large aperture internal focusing telephoto lens has four lens groups with focal power, and in the focusing process, the second lens group moves along the optical axis toward the image side, the third lens group moves along the optical axis toward the object side, and the first lens group and the fourth lens group remain unchanged relative to the image plane; The first lens group includes, from the object side to the image side, a first lens with positive power, a second lens with positive power, a third lens with positive power, a fourth lens with positive power, a fifth lens with negative power and a sixth lens with positive power, and the first lens group has six lenses; The second lens group includes, from the object side to the image side, an eighth lens having negative refractive power and a ninth lens having negative refractive power, and the second lens group has two lenses; The third lens group includes, from the object side to the image side, a tenth lens with negative power, an eleventh lens with positive power, and a twelfth lens with positive power, and the number of lenses of the third lens group is three; the fourth lens group includes, from the object side to the image side, a thirteenth lens with positive power, a fourteenth lens with negative power, a fifteenth lens with positive power, a sixteenth lens with negative power, and a seventeenth lens with negative power, and the number of lenses of the fourth lens group is five; A large aperture internal focusing telephoto lens meets the following conditions: 0≤F1 / F≤2, (1); -2≤F2 / F≤0, (2); 0≤F3 / F≤2.5, (3); -6≤F4 / F≤0, (4); Among them, F1 represents the composite focal length of the first lens group, F2 represents the composite focal length of the second lens group, F3 represents the composite focal length of the third lens group, F4 represents the composite focal length of the fourth lens group, and F represents the composite focal length of the photographic lens.

9. The large aperture inner focusing telephoto lens according to claim 8, characterized in that: In the first lens group, the fourth lens and the fifth lens are combined into a first cemented lens with positive power; the sixth lens is an aspherical lens; the refractive index Nd of the first lens and the fifth lens is ≥1.8; the Abbe number Vd of the second lens, the third lens and the fourth lens is ≥60; in the third lens group, the tenth lens and the eleventh lens are combined into a third cemented lens with negative power.

10. The large aperture inner focusing telephoto photography lens according to claim 8, characterized in that: In the fourth lens group, the thirteenth lens and the fourteenth lens are combined into a fourth cemented lens with negative power; the fifteenth lens and the sixteenth lens are combined into an eighth cemented lens with negative power.

Images