Internal-focusing ultra-wide-angle full-frame camera lens

Abstract

The utility model discloses an internal focusing ultra-wide-angle full-frame camera lens. The internal focusing ultra-wide-angle full-frame camera lens sequentially comprises a first lens group, a second lens group, a third lens group, an iris diaphragm, a fourth lens group and a fifth lens group from an object side to an imaging surface, the first lens group serves as a fixed group, has negative focal power and comprises a first lens and a second lens; the second lens group serves as a fixed group, has positive focal power and comprises a third lens and a fourth lens; the third lens group is used as a focusing group, has negative focal power, and is used as a focusing compensation group to move towards the object space when focusing is carried out from infinity to a near position; according to the utility model, the aberration is effectively corrected, the F1.8 maximum aperture is realized, the excellent performance can be obtained, the super-large visual angle is achieved, the distortion is effectively inhibited, and the distortion is less than 3%; the structure is short and light, the moving group only comprises one lens, the weight and the moving stroke of the moving group are obviously reduced, and the focusing efficiency is effectively guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to camera lens technical field, concretely is a kind of inner focusing ultra-wide-angle full-frame camera lens. BACKGROUND

[0002] Ultra-wide-angle lens as a unique lens type in photography field, has been favored by many photographers and photography enthusiasts, its unique perspective and wide field of view, so that it has incomparable advantage in the shooting scenery, building and large-scale activities etc.In photography practice, ultra-wide-angle lens can bring unique visual experience, it can increase the spatial depth of photographic picture, so that picture has more level and stereoscopic sense.Meanwhile, due to the long depth of field, ultra-wide-angle lens can ensure that the front and back scene of the subject can be clearly reproduced on picture.In addition, the coverage area of ultra-wide-angle lens is large, and the range of shooting scene is wide, and large shooting object can be shot as a whole in the case of being very close to shooting object.These characteristics make ultra-wide-angle lens play an important role in landscape photography, architectural photography, documentary photography and other fields, therefore, the utility model designs a kind of inner focusing ultra-wide-angle full-frame camera lens to improve the above problems. SUMMARY

[0003] In view of the deficiencies of prior art, the utility model aims at providing a kind of inner focusing ultra-wide-angle full-frame camera lens, can effectively correct aberration, while realizing F1.8 maximum aperture, can obtain superior performance, while reaching ultra-large angle of view, effectively suppress distortion, and distortion is less than 3%;Structure is short and small light weight, and mobile group only contains a lens, significantly reduces the weight and moving stroke of mobile group, effectively guarantees focusing efficiency.

[0004] To achieve the above object, the utility model provides the following technical scheme:

[0005] A kind of inner focusing ultra-wide-angle full-frame camera lens, from object side to imaging surface successively includes first lens group, second lens group, third lens group, variable diaphragm, fourth lens group and fifth lens group;

[0006] The first lens group as fixed group, with negative refractive power, including first lens and second lens;

[0007] The second lens group as fixed group, with positive refractive power, including third lens and fourth lens;

[0008] The third lens group as focusing group, with negative refractive power, including fifth lens, when focusing from infinity to near, the third lens group as focusing compensation group moves to object side;

[0009] The fourth lens group, as a fixed group, has positive refractive power and includes a sixth lens, a seventh lens, an eighth lens, a ninth lens and a tenth lens;

[0010] The fifth lens group, as a fixed group, has negative refractive power and includes an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens.

[0011] Preferably, the first lens group includes two pieces of meniscus negative lenses with the image side bent, and satisfies the following conditions:

[0012] -1.98<FG1 / f<-1.14

[0013] Where FG1 is the focal length of the first lens group, and f is the focal length of the camera lens optical system. Preferably, the second lens is a glass aspheric negative lens with the image side bent, and satisfies the following conditions:

[0014] G2R2<20mm

[0015] -3.19<F2 / f<-2.05

[0016] Where G2R2 is the radius of curvature of the side of the second lens close to the imaging surface, F2 is the focal length of the second lens, and f is the focal length of the camera lens optical system.

[0017] Preferably, the second lens group is composed of one piece of negative lens and one piece of positive lens, and satisfies the following conditions:

[0018] Nd<1.84

[0019] d<0.6mm

[0020] Where Nd is the refractive index of the lens in the second lens group, d is the interval from the negative lens to the positive lens in the second lens group, and f is the focal length of the camera lens optical system.

[0021] Preferably, the last piece of lens in the second lens group is a glass aspheric positive lens with double convex shape, and satisfies the following conditions:

[0022] 0.81<F4 / f<2.50

[0023] Where F4 is the focal length of the last piece of lens in the second lens group, and f is the focal length of the camera lens optical system.

[0024] Preferably, the third lens group is a single piece of negative lens with the object side bent, and satisfies the following conditions:

[0025] 0<(G5R2+G5R1) / (G5R2-G5R1)<2.1

[0026] Wherein, G5R1 is the curvature radius of the negative lens close to the object side, and G5R2 is the curvature radius of the negative lens close to the imaging surface.

[0027] Preferably, at least two lenses in the fourth lens group satisfy the following conditions:

[0028] Vd>68

[0029] Wherein, Vd is the Abbe number of the lens material in the fourth lens group.

[0030] Preferably, the fourth lens group contains a set of three cemented lenses, at least one of which contains a negative lens and a positive lens, and satisfies the following conditions:

[0031] Ndn-Ndp>0.2

[0032] -5.77<FB1 / f<-1.92

[0033] Wherein, Ndn is the refractive index of the negative lens in the three cemented lenses, Ndp is the refractive index of the positive lens in the three cemented lenses, FB1 is the focal length of the three cemented lenses, and f is the focal length of the camera lens optical system.

[0034] Preferably, the fourth lens group and the fifth lens group satisfy the following conditions:

[0035] 0.22<FG4 / FG5<1.03

[0036] Wherein, FG4 is the focal length of the fourth lens group, and FG5 is the focal length of the fifth lens group.

[0037] Compared with the prior art, the beneficial effects of the utility model are:

[0038] The utility model effectively corrects aberration, realizes F1.8 maximum aperture, and can obtain superior performance, effectively suppresses distortion while achieving super large viewing angle, and the distortion is less than 3%; the structure is short and light, the moving group only contains one lens, the weight and moving stroke of the moving group are significantly reduced, and the focusing efficiency is effectively guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a lens structure schematic diagram of an inner focusing super wide angle full frame camera lens.

[0040] Figure 2 It is a spherical aberration curve diagram of the inner focusing super wide angle full frame camera lens.

[0041] Figure 3 It is a field curvature curve diagram of the inner focusing super wide angle full frame camera lens.

[0042] Figure 4 Distortion curve diagram of an inner focusing super-wide-angle full-frame camera lens.

[0043] In the figure: G1, first lens group; G2, second lens group; G3, third lens group; G4, fourth lens group; G5, fifth lens group; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, sixth lens; 7, seventh lens; 8, eighth lens; 9, ninth lens; 10, tenth lens; 11, eleventh lens; 12, twelfth lens; 13, thirteenth lens; 14, fourteenth lens; 15, fifteenth lens. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] Embodiment:

[0046] Please refer to Figure 1 The embodiment provides an inner focusing super-wide-angle full-frame camera lens, which comprises a first lens group G1, a second lens group G2, a third lens group G3, a variable diaphragm, a fourth lens group G4 and a fifth lens group G5 in sequence from an object side to an imaging surface.

[0047] The first lens group G1 is a fixed group, has negative refractive power, comprises a first lens 1 and a second lens 2, and the second lens 2 is an aspherical lens.

[0048] The second lens group G2 is a fixed group, has positive refractive power, comprises a third lens 3 and a fourth lens 4, and the fourth lens 4 is an aspherical lens.

[0049] The third lens group G3 is a focusing group, has negative refractive power, comprises a fifth lens 5, and when focusing from infinity to near, the third lens group G3 moves towards the object side as a focusing compensation group (moving group), and the fifth lens 5 is an aspherical lens.

[0050] The fourth lens group G4 is a fixed group, has positive refractive power, comprises a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9 and a tenth lens 10, and the sixth lens 6 is an aspherical lens.

[0051] The fifth lens group G5 is a fixed group with negative refractive power, and includes the eleventh lens 11, the twelfth lens 12, the thirteenth lens 13, the fourteenth lens 14 and the fifteenth lens 15, wherein the fifteenth lens 15 is an aspherical lens. The number of lenses in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4 and the fifth lens group G5 can be designed according to the design and use requirements, and the number of lenses can be increased or decreased, which belongs to the protection scope of the present application.

[0052] In the embodiment, the first lens group G1 includes two meniscus negative lenses with the concave side facing the image side, and satisfies the following conditions:

[0053] -1.98 < FG1 / f < -1.14

[0054] Wherein FG1 is the focal length of the first lens group G1, and f is the focal length of the camera lens optical system.

[0055] In the embodiment, the second lens 2 is a glass aspherical negative lens with the concave side facing the image side, and satisfies the following conditions:

[0056] G2R2 < 20 mm

[0057] -3.19 < F2 / f < -2.05

[0058] Wherein G2R2 is the radius of curvature of the side of the second lens 2 close to the imaging surface, F2 is the focal length of the second lens 2, and f is the focal length of the camera lens optical system.

[0059] In the embodiment, the second lens group G2 is composed of one negative lens and one positive lens, and satisfies the following conditions:

[0060] Nd < 1.84

[0061] d < 0.6 mm

[0062] Wherein Nd is the refractive index of the lens in the second lens group G2, d is the interval between the negative lens and the positive lens in the second lens group G2, and f is the focal length of the camera lens optical system.

[0063] In the embodiment, the last lens (i.e. the fourth lens 4) in the second lens group G2 is a glass aspherical positive lens with a biconvex shape, and satisfies the following conditions:

[0064] 0.81 < F4 / f < 2.50

[0065] Wherein F4 is the focal length of the last lens (the fourth lens 4) in the second lens group G2, and f is the focal length of the camera lens optical system.

[0066] In the embodiment, the third lens group G3 (i.e. the fifth lens 5) is a single negative lens bending toward the object side, and satisfies the following conditions:

[0067] 0 < (G5R2+G5R1) / (G5R2-G5R1) < 2.1

[0068] wherein G5R1 is the radius of curvature of the side of the negative lens (the fifth lens 5) close to the object side, and G5R2 is the radius of curvature of the side of the negative lens (the fifth lens 5) close to the imaging surface.

[0069] In the embodiment, at least two lenses in the fourth lens group G4 satisfy the following conditions:

[0070] Vd > 68

[0071] wherein Vd is the Abbe number of the lens material of the lens in the fourth lens group G4.

[0072] In the embodiment, the fourth lens group G4 contains a set of three cemented lenses, and at least one negative lens and one positive lens are contained in the three cemented lenses, and satisfy the following conditions:

[0073] Ndn-Ndp > 0.2

[0074] -5.77 < FB1 / f < -1.92

[0075] wherein Ndn is the refractive index of the negative lens in the three cemented lenses, Ndp is the refractive index of the positive lens in the three cemented lenses, FB1 is the focal length of the three cemented lenses, and f is the focal length of the camera lens optical system.

[0076] In the embodiment, the fourth lens group G4 and the fifth lens group G5 satisfy the following conditions:

[0077] 0.22 < FG4 / FG5 < 1.03

[0078] wherein FG4 is the focal length of the fourth lens group G4, and FG5 is the focal length of the fifth lens group G5.

[0079] As a preferred embodiment of the technical solution, the parameters of the camera lens embodiment are shown in Table 1 below, wherein the aspherical coefficients of the aspherical lens are shown in Table 2 below, and the surface number in the surface serial number column shows the surface number when the surface close to the object side is set as the first surface and the surface number is sequentially increased toward the imaging surface side, and the shape parameters of each lens are as follows:

[0080] Table 1

[0081]

[0082]

[0083] Table 2

[0084]

[0085]

[0086] As a preferred technical solution, the positions of the focusing compensation group (moving group) of the camera lens in different focusing states in the embodiment are shown in Table 3, that is, the values of the two states of D1 and D2 in Table 1:

[0087] Table 3

[0088] Conjugate distance Infinity Closest (0.3 m) D1 5.45 mm 2.97 mm D2 2.47 mm 4.95 mm

[0089] As a preferred technical solution, the physical parameters of the camera lens in the embodiment are shown in Table 4:

[0090] Table 4

[0091] Focal length f 15.04 mm Relative aperture FNO. 1.85 Field of view angle ω 105.7° Optical total length 123 mm

[0092] Figure 2 The spherical aberration curve of the camera lens in the embodiment is shown in FIG. 3, Figure 3 The field curvature curve of the camera lens in the embodiment is shown in FIG. 4, Figure 4 The distortion curve of the camera lens in the embodiment is shown in FIG. 5, and it can be seen that the camera lens in the embodiment has good imaging effect.

[0093] In the embodiment, the above-mentioned conditional formula is limited to effectively correct aberration, superior performance can be obtained while achieving F1.8 maximum aperture, distortion is effectively suppressed while achieving super large viewing angle, the distortion is less than 3%; the structure is short and light, the moving group only contains one lens, the weight and moving stroke of the moving group are significantly reduced, and the focusing efficiency is effectively guaranteed.

[0094] The above-mentioned embodiment is a preferred implementation scheme of the present application, in addition to this, the present application can also be implemented in other ways, any obvious replacement without departing from the technical solution concept of the present application is within the protection scope of the present application.

Claims

1. An inner focusing ultra-wide full-frame camera lens characterized by: From the object side to the imaging plane, the camera lens optical system comprises a first lens group (G1), a second lens group (G2), a third lens group (G3), a variable diaphragm, a fourth lens group (G4) and a fifth lens group (G5) in sequence; The first lens group (G1) is a fixed group, has negative refractive power, and comprises a first lens (1) and a second lens (2); The second lens group (G2) is a fixed group, has positive refractive power, and comprises a third lens (3) and a fourth lens (4); The third lens group (G3) is a focusing group, has negative refractive power, and comprises a fifth lens (5); when focusing from infinity to close range, the third lens group (G3) moves to the object side as a focusing compensation group; The fourth lens group (G4) is a fixed group, has positive refractive power, and comprises a sixth lens (6), a seventh lens (7), an eighth lens (8), a ninth lens (9) and a tenth lens (10); The fifth lens group (G5) is a fixed group, has negative refractive power, and comprises an eleventh lens (11), a twelfth lens (12), a thirteenth lens (13), a fourteenth lens (14) and a fifteenth lens (15).

2. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: The first lens group (G1) comprises two meniscus negative lenses curved toward the image side, and satisfies the following conditions: -1.98<FG1 / f<-1.14 Where FG1 is the focal length of the first lens group (G1), and f is the focal length of the camera lens optical system.

3. An internal focus ultra-wide full-frame camera lens according to claim 1, characterized in that: The second lens (2) is a glass aspheric negative lens curved toward the image side, and satisfies the following conditions: G2R2<20mm -3.19<F2 / f<-2.05 Where G2R2 is the radius of curvature of the side of the second lens (2) close to the imaging plane, F2 is the focal length of the second lens (2), and f is the focal length of the camera lens optical system.

4. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: The second lens group (G2) is composed of one negative lens and one positive lens, and satisfies the following conditions: Nd<1.84 d<0.6mm Where Nd is the refractive index of the lens in the second lens group (G2), d is the interval between the negative lens and the positive lens in the second lens group (G2), and f is the focal length of the camera lens optical system.

5. An inner focusing ultra-wide full-frame camera lens according to claim 4, characterized in that: The last lens in the second lens group (G2) is a glass aspheric positive lens with a double-convex shape, and satisfies the following conditions: 0.81<F4 / f<2.50 Where F4 is the focal length of the last lens in the second lens group (G2), and f is the focal length of the camera lens optical system.

6. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: The third lens group (G3) is a single negative lens curved toward the object side, and satisfies the following conditions: 0<(G5R2+G5R1) / (G5R2-G5R1)<2.1 Where G5R1 is the radius of curvature of the side of the negative lens close to the object side, and G5R2 is the radius of curvature of the side of the negative lens close to the imaging plane.

7. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: At least two lenses in the fourth lens group (G4) satisfy the following conditions: Vd>68 Where Vd is the Abbe number of the lens material in the fourth lens group (G4).

8. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: The fourth lens group (G4) contains a set of three cemented lenses, and at least one negative lens and one positive lens are contained in the three cemented lenses, and satisfy the following conditions: Ndn-Ndp > 0.2 -5.77 < FB1 / f < -1.92 wherein Ndn is the refractive index of a negative lens in the triplet lens, Ndp is the refractive index of a positive lens in the triplet lens, FB1 is the focal length of the triplet lens, and f is the focal length of the camera lens optical system.

9. An inner focusing ultra-wide full-frame camera lens according to claim 1, characterized in that: The fourth lens group (G4) and the fifth lens group (G5) satisfy the following condition: 0.22 < FG4 / FG5 < 1.03 wherein FG4 is the focal length of the fourth lens group (G4), and FG5 is the focal length of the fifth lens group (G5).

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