JP2006047944A - Photographing lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographing lens in which a photographic angle of view is wide and brightness and a cost reduction are satisfied. <P>SOLUTION: The photographing lens 10 includes first, second and third lens elements (11 to 13) arranged in a sequence from an object side. The first lens element (11) is a positive meniscus with a positive power. The second lens element (12) is a positive meniscus and has a convex surface convex to the object side. The third lens element (13) is a negative meniscus and has a concave surface oriented to the object side. The first lens element 11 and the third lens element 13 are made of an optical resin whereas the second lens element 12 is made of an optical glass. The convex face of the first lens element 11 on the object side and the concave face of the third lens element 13 on the object side are aspherical. The photographic lens satisfies conditions of: (1) 0.49<¾f2/f3¾<1.0, and (2) 0.5<f23/f<4 where f2 is a focal length of the second lens element 12, f3 is a focal length of the third lens element 13f, f is a lens system composite focal length and f23 is a composite focal length of the second lens element 12 and third lens element. Thus, the photographing lens with a brightness of F4.0 and a photographic angle of view of 81.6° can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inexpensive photographing lens that is suitable for a compact camera or a lens-fitted photo film unit and that can obtain a wide field angle with a field angle 2ω of 70 to 80 degrees.

  An unexposed photographic film is built in at the time of manufacture, and a lens-fitted photo film unit that can be photographed on the spot is known. For example, various types of lens unit with a lens are sold, such as a high-sensitivity material having an ISO sensitivity of 1600 and a photographing lens having an F6.2 that improves the quality of background description. In recent years, photographing devices that are convenient to carry, such as digital cameras and mobile phones with cameras, have been widely used. Under such circumstances, there is an increasing demand for photographing lenses having a wide angle of view and a large aperture so as to cope with diversification of photographing scenes and capable of photographing a wider range than before.

  As one of wide-angle and large-diameter photographing lenses, a so-called triplet-type photographing lens having a three-lens structure in which positive, negative, and positive lenses are combined in order from the object side is widely used. For example, as disclosed in Patent Document 1, a triplet type photographing lens uses a high refractive index and low dispersion material for two positive lenses and a low refractive index and high dispersion material for a central negative lens. Although it is known that the surface curvature can be corrected, there is a drawback that the cost is increased by using many high refractive index materials.

  Therefore, the photographing lens shown in Patent Document 2 or Patent Document 3 uses a material having a relatively low refractive index in order to reduce the cost. The photographing lens described in Patent Document 2 is bright in F number as F4 in those shown in Examples 1 to 6, but the photographing angle of view is less than 70 degrees, and those shown in Examples 7 through 11 are as follows. The shooting angle of view is as wide as about 72 degrees, but the F number is as dark as F4.5. The photographic lens described in Patent Document 3 uses a material having a lower refractive index than that of the photographic lens described in Patent Document 2, but the photographic field angle is narrow and the F-number is F4. 5 was the limit.

Further, as lens types different from the triplet type, photographing lenses described in Patent Literature 4 and Patent Literature 5 are known. Patent Document 4 discloses a photographing lens having three lenses of negative, positive, and positive powers in order from the object side, but has a disadvantage of a large distortion of 15.9%. Patent Document 5 discloses a photographing lens having three lenses of negative power, positive power, and negative power in order from the object side, and the F number is F2.8 to ensure sufficient brightness. However, there is a drawback that the shooting angle of view is as narrow as 65 degrees.
JP-A-7-35972 JP-A-8-201686 Japanese Patent Laid-Open No. 9-133860 JP-A-8-220430 JP 2003-149545 A

  As described above, the conventional photographing lens has at least one of the disadvantages of high cost, insufficient brightness, and a narrow angle of view. A lens was desired.

  The present invention has been made in consideration of the above-mentioned background. It has three lenses, can provide a brightness of F3.5 to F4, a wide shooting angle of view of 70 to 80 degrees, and uses a low refractive index material. An object of the present invention is to provide a photographing lens capable of reducing the cost and ensuring the performance.

In order to achieve the above object, in the photographing lens according to claim 1, in order from the object side, a convex surface is directed to the object side, and at least one surface is an aspherical first lens, a positive power second lens, A negative lens with a concave surface facing the object side, f is the total focal length of the entire system, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f23 is the second lens And the combined focal length of the third lens,
(1) 0.49 <| f2 / f3 | <1.0
(2) 0.5 <f23 / f <4
It is characterized by satisfying.

  When the upper limit of conditional expression (1) is exceeded, that is, when the focal length of the second lens is increased, it becomes difficult to reduce the Petzval sum with a small number of lenses, and field curvature and astigmatism increase. The brightness of F4 cannot be realized. On the other hand, when the lower limit is exceeded, the eccentricity sensitivity between the second lens and the third lens becomes high, performance deterioration due to a slight manufacturing error is large, and manufacturing suitability is deteriorated. When the lower limit of conditional expression (2) is exceeded, the first lens becomes a strong concave lens, resulting in a problem that the total lens length increases. When the upper limit of conditional expression (2) is exceeded, the first lens becomes a strong convex lens, so that the error sensitivity due to decentration between the first lens and the second / third lens increases, and the light is emitted toward the image plane. The angle of the light beam becomes large and it becomes difficult to secure the peripheral light amount.

In the photographic lens according to claim 2, the second lens is configured by a plano-convex lens having a convex surface facing the image side or a positive meniscus lens having a convex surface facing the image side, and N1 is a refractive index of the first lens, When N3 is the refractive index of the third lens,
(3) N1 <N3
The relationship between the shape of the second lens and the refractive index of the first lens and the third lens is defined. When using a material that satisfies the conditional expression (3), the second lens is preferably a meniscus lens convex to the image side. When the conditional expression (3) is not satisfied, it is difficult to correct the field curvature.

According to a third aspect of the present invention, the second lens is composed of a biconvex lens having a convex surface having a small curvature radius on the image side or a plano-convex lens having a convex surface facing the image side, and N1 is a refractive index of the first lens. And when N3 is the refractive index of the third lens,
(4) | N1-N3 | <0.13
The relationship between the shape of the second lens and the refractive index of the first lens and the third lens is defined. When using a material that satisfies the conditional expression (4), the second lens is preferably a biconvex lens or a plano-convex lens having a convex surface having a large curvature on the image side. If the conditional expression (4) is not satisfied, it is difficult to correct the field curvature.

  The photographic lens described in claim 4 is characterized in that at least one surface of the third lens is an aspheric surface, and can correct spherical aberration, coma aberration, and astigmatism.

In the photographic lens according to claim 5, when the first lens and the third lens are made of resin, the second lens is made of glass, and the refractive power of the first lens is p1,
(5) p1 ≧ 0
(6) 0.35 <f2 / f <0.9
Is satisfied. Conditional expression (5) defines the range of the focal length of the first lens, and defines that the lens is a positive lens or a non-power lens having the same curvature on both sides. Conditional expression (6) defines the range of the focal length of the second lens. By satisfying these conditional expressions, it is possible to reduce the focus fluctuation due to the environmental temperature change inherent to the resin.

  According to a sixth aspect of the present invention, the first lens and the third lens are aspheric glass lenses.

  The photographic lens according to claim 7 is characterized in that the second lens is composed of a biconvex lens having a convex surface with a small radius of curvature on the image side, and all the lenses from the first lens to the third lens are made of the same material. To do.

  The photographic lens described in claim 8 is characterized in that at least one surface of the second lens is aspherical, and spherical aberration, coma and astigmatism are corrected.

  The photographic lens described in claim 9 is characterized in that at least one surface of the second lens and the third lens is an aspheric surface, and corrects spherical aberration, coma aberration, and astigmatism.

  According to the tenth aspect of the present invention, the first, second and third lenses are made of resin lenses, and the cost can be reduced most.

  According to the present invention, in order from the object side, a first lens having a convex surface facing the object side, a second lens having a positive power, and a third lens having a negative power having a concave surface facing the object side are provided. Therefore, it is possible to realize a low-cost photographic lens in which the brightness of F number F3.5 to F4 is ensured and the photographic angle of view is wide.

Example 1
In FIG. 1, the photographing lens 10 includes, in order from the object side, a first lens 11 having a positive power, a second lens 12 having a positive power, and a third lens 13 having a negative power. The first lens 11 is a positive meniscus lens having a convex surface facing the object side, the second lens 12 is a positive meniscus lens having a convex surface facing the image side, and the third lens 13 has a concave surface facing the object side. Negative meniscus lens. The first lens 11 and the third lens 13 are made of optical resin, and the second lens 12 is made of optical glass. A diaphragm is provided between the first lens 11 and the second lens 12. The object side surface of the first lens 11 and the object side surface of the third lens 13 are aspheric surfaces.

Table 1 below shows lens data and aspherical coefficients of the taking lens 10. It corresponds to the surface number given to the curved surface of each lens in order from the object side, and shows the radius of curvature of each surface, the surface interval, the refractive index with respect to d-line (587.56 nm), and the Abbe number. The same applies to the other embodiments. Each aspheric surface is
Z = ch ² / [1+ {1− (1 + K) c ² h ² } ^1/2 ]
+ Ah ⁴ + Bh ⁶ + Ch ⁸ + Dh ¹⁰
It is a curved surface that satisfies In the formula, c represents the reciprocal of the radius of curvature (= 1 / Ri), and h represents the height from the optical axis.

The specification of the taking lens 10 is that the combined focal length of all lenses is f, the focal length of the first lens 11 is f1, the focal length of the second lens 12 is f2, the focal length of the third lens 13 is f3, and the second lens. 12 and the third lens 13 has a combined focal length of f23, an F number of Fno, a shooting angle of view of 2ω, a lens total length of L, a Petzval sum of Pz, and a back focus when the temperature changes by 30 degrees with respect to the reference temperature. The amount of change is fb (30 degrees), and each value is
f = 26.00mm
f1 = 35.99mm
f2 = 15.36mm
f3 = -18.10mm
f23 = 73.25mm
Fno = 4.0
2ω = 81.6 °
L = 32.60mm
Pz = −0.510
fb (30 degrees) = 0.049 mm
It is. In addition, Petzval sum Pz described the calculation result using optical design software Code-V of the USA ORA company.

From these numerical values, the ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 15.36 / -18.10 | = 0.591
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (73.25 / 26) = 2.82
And satisfies the conditional expression (2). For conditional expression (3),
N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is clear that the first lens 21 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (15.36 / 26) = 0.591
And conditional expression (6) is satisfied.

  FIG. 2 shows aberration diagrams of the taking lens 10. The spherical aberration is a curve with g, d, and C in the figure for the g-line (435.84 nm), d-line (587.56 nm), and C-line (656.28 nm), respectively. The image surface curvature is expressed on the basis of a converted curvature radius (-149.330 mm) obtained by converting the image surface (film surface) curved with a curvature radius of −100 mm in the horizontal direction with respect to the diagonal direction, and relates to the sagittal image surface. A curve with S indicating a value and a curve with T indicating a value related to the tangential image plane are shown together.

(Example 2)
In FIG. 3, the photographic lens 20 according to the second embodiment includes a first lens 21 having a positive power, a second lens 22 having a positive power, and a third lens 23 having a negative power in order from the object side. The first lens 21 is a positive meniscus lens having a convex surface facing the object side, the second lens 22 is a positive meniscus lens having a convex surface facing the image side, and the third lens 23 has a concave surface facing the object side. Negative meniscus lens. The first lens 21 and the third lens 23 are made of optical resin, and the second lens 22 is made of optical glass. The object side convex surface of the first lens 21 and the object side concave surface of the third lens 23 are aspherical surfaces, respectively. Table 2 below shows lens data and aspherical coefficients of the taking lens 20.

The specification of the taking lens 20 is
f = 26.00mm
f1 = 33.72mm
f2 = 17.62mm
f3 = -21.49mm
f23 = 84.51mm
Fno = 4.03
2ω = 81.4 °
L = 31.90mm
Pz = −0.520
fb (30 degrees) = 0.054 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 17.62 / -21.49 | = 0.820
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (84.51 / 26) = 3.25
And satisfies the conditional expression (2). For conditional expression (3),
N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is clear that the first lens 21 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (17.14 / 26) = 0.678
And conditional expression (6) is satisfied. FIG. 4 shows aberration diagrams of the taking lens 20. The image surface curvature is expressed with reference to a converted curvature radius (-149.330 mm) obtained by converting an image surface (film surface) curved with a curvature radius of −100 mm in the horizontal direction in the diagonal direction.

(Example 3)
In FIG. 5, the photographing lens 30 according to the third embodiment of the present invention includes a first lens 31 having a positive power, a second lens 32 having a positive power, and a third lens 33 having a negative power in order from the object side. . The first lens 31 is a positive meniscus lens having a convex surface facing the object side, the second lens 32 is a positive meniscus lens having a convex surface facing the image side, and the third lens 33 has a concave surface facing the object side. Negative meniscus lens. The first lens 31 and the third lens 33 are made of optical resin, and the second lens 32 is made of optical glass. The object side surface of the first lens 31 and the object side surface of the third lens 33 are each aspheric. Table 3 below shows lens data and aspheric coefficients of the taking lens 30.

The specification of the photographic lens 30 is
f = 26.00mm
f1 = 37.32mm
f2 = 17.14mm
f3 = -20.80mm
f23 = 71.24mm
Fno = 4.03
2ω = 81.0 °
L = 31.06mm
Pz = −0.486
fb (30 degrees) = 0.045 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 17.14 / -20.80 | = 0.824
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (71.24 / 26) = 2.74
And satisfies the conditional expression (2). Further, with respect to conditional expression (3), from Table 3, N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). As for conditional expression (5), it is clear that the first lens 31 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (17.14 / 26) = 0.659
And conditional expression (6) is satisfied. FIG. 6 is an aberration diagram of the taking lens 30. Note that the image surface curvature is represented with reference to a converted curvature radius (−220.0 mm) obtained by converting an image surface (film surface) curved in a horizontal direction with a curvature radius of −150 mm in the diagonal direction.

Example 4
In FIG. 7, the photographing lens 40 according to the fourth embodiment includes a first lens 41 having a positive power, a second lens 42 having a positive power, and a third lens 43 having a negative power in order from the object side. The first lens 41 is a positive meniscus lens having a convex surface facing the object side, the second lens 42 is a positive meniscus lens having a convex surface facing the image side, and the third lens 43 has a concave surface facing the object side. Negative meniscus lens. The first lens 41 and the third lens 43 are made of optical resin, and the second lens 42 is made of optical glass. The object side surface of the first lens 41 and the object side surface of the third lens 43 are aspherical surfaces, respectively. Table 4 below shows lens data and aspherical coefficients of the taking lens 40.

The specification of the taking lens 40 is
f = 26.00mm
f1 = 36.19mm
f2 = 16.60mm
f3 = −19.34 mm
f23 = 77.17mm
Fno = 3.5
2ω = 81.0 °
L = 32.07mm
Pz = −0.520
fb (30 degrees) = 0.047 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 16.60 / −19.34 | = 0.858
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (77.17 / 26) = 2.97
And satisfies the conditional expression (2). Further, with respect to conditional expression (3), from Table 5, N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is obvious that the first lens 51 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (16.60 / 26) = 0.639
And conditional expression (6) is satisfied. FIG. 8 shows aberration diagrams of the taking lens 40. Note that the image surface curvature is represented with reference to a converted curvature radius (−220.0 mm) obtained by converting an image surface (film surface) curved in a horizontal direction with a curvature radius of −150 mm in the diagonal direction.

(Example 5)
In FIG. 9, the photographing lens 50 according to the fifth embodiment includes a first lens 51 having a positive power, a second lens 52 having a positive power, and a third lens 53 having a negative power in order from the object side. The first lens 51 is a biconvex lens with a small curvature radius of the convex surface on the object side, the second lens 52 is a positive meniscus lens with the convex surface facing the image side, and the third lens 53 has a concave surface on the object side. This is a negative meniscus lens. The first lens 51 and the third lens 53 are made of optical resin, and the second lens 52 is made of optical glass. The object side surface of the first lens 51 and the object side surface of the third lens 53 are aspheric surfaces. Table 5 below shows lens data and aspherical coefficients of the taking lens 50.

The specification of the taking lens 50 is
f = 26.00mm
f1 = 51.63mm
f2 = 13.63mm
f3 = -15.27 mm
f23 = 48.74mm
Fno = 4.0
2ω = 80.80 °
L = 33.30mm
Pz = −0.330
fb (30 degrees) = 0.005 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 13.63 / −15.27 | = 0.893
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (48.74 / 26) = 1.87
And satisfies the conditional expression (2). Further, with respect to conditional expression (3), from Table 5, N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is obvious that the first lens 11 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (13.63 / 26) = 0.524
And conditional expression (6) is satisfied. FIG. 10 is an aberration diagram of the taking lens 50. In this embodiment, the image plane is flat (planar).

(Example 6)
In FIG. 11, a photographic lens 60 according to the sixth embodiment includes a first lens 61 having a positive power, a second lens 62 having a positive power, a third lens 63 having a negative power, and a plane parallel plate 64 in order from the object side. It consists of. The first lens 61 is a positive meniscus lens having a convex surface facing the object side, the second lens 22 is a positive meniscus lens having a convex surface facing the image side, and the third lens 23 is concave on the object side and has a convex surface on the image side. It is a flat negative lens. The first lens 61 and the third lens 63 are made of optical resin, and the second lens 62 and the plane parallel plate 64 are made of optical glass. The image-side concave surface of the first lens 61 and the object-side concave surface of the third lens 63 are aspheric surfaces. Table 6 below shows lens data and aspherical coefficients of the taking lens 60.

The specification of the taking lens 60 is
f = 7.50mm
f1 = 58.02mm
f2 = 3.46mm
f3 = −5.74 mm
f23 = 7.76mm
Fno = 3.5
2ω = 70.0 °
L = 10.76mm
Pz = −0.110
fb (30 degrees) = − 0.024 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 3.46 / −5.74 | = 0.603
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (7.76 / 7.5) = 1.03
And satisfies the conditional expression (2). Further, with respect to conditional expression (3), from Table 6, N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is obvious that the first lens 61 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (3.46 / 7.5) = 0.461
And conditional expression (6) is satisfied. FIG. 12 shows aberration diagrams of the taking lens 60. In this embodiment, the image surface is flat.

(Example 7)
In FIG. 13, the photographing lens 70 according to the seventh embodiment includes a first lens 71 having a positive power, a second lens 72 having a positive power, and a third lens 73 having a negative power in order from the object side. The first lens 71 is a positive meniscus lens having a convex surface facing the object side, the second lens 72 is a positive meniscus lens having a convex surface facing the image side, and the third lens 73 has a concave surface facing the object side. Negative meniscus lens. The first lens 71 and the third lens 73 are made of optical resin, and the second lens 72 is made of optical glass. The object-side convex surface of the first lens 71 and the object-side concave surface of the third lens 73 are aspheric surfaces. Table 7 below shows lens data and aspherical coefficients of the taking lens 70.

The specification of the taking lens 70 is
f = 26.00mm
f1 = 35.19mm
f2 = 22.10mm
f3 = −26.72 mm
f23 = 97.67mm
Fno = 4.03
2ω = 81.4 °
L = 30.46mm
Pz = −0.530
fb (30 degrees) = 0.079 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 22.10 / −26.72 | = 0.827
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (97.67 / 26) = 3.76
And satisfies the conditional expression (2). For conditional expression (3), from Table 7, N1 = 1.492, N3 = 1.585
And satisfies the conditional expression (3). Regarding conditional expression (5), it is obvious that the first lens 71 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (22.10 / 26) = 0.85
And conditional expression (6) is satisfied. FIG. 14 shows aberration diagrams of the taking lens 70. The image surface curvature is expressed with reference to a converted curvature radius (−220.0 mm) obtained by converting an image surface (film surface) curved in a horizontal direction with a curvature radius of −150 mm in the diagonal direction.

In the photographing lenses 10 to 70 according to the first to seventh embodiments, the focal length f2 of the second lens and the combined focal length f of the entire system are 0.4 <f2 / f <0.9.
When the Abbe numbers of the second lens and the third lens are ν2 and ν3,
ν2> ν3
Meet. Also, when the powers of the first lens, the second lens, and the third lens are P1, P2, and P3, respectively,
P1 <| P3 | <P2
Satisfied.

(Example 8)
In FIG. 15, the photographing lens 80 according to the eighth embodiment includes a first lens 81 having a positive power, a second lens 82 having a positive power, and a third lens 83 having a negative power in order from the object side. The first lens 81 is a positive meniscus lens in which the radius of curvature of the object-side convex surface is slightly small. The second lens 82 is a biconvex lens in which the curvature on the object-side convex surface is gentle and the curvature on the image-side convex surface is increased, and the third lens 83 is a negative meniscus lens with the concave surface facing the object side. The first lens 81 to the third lens 83 are all made of optical glass. A diaphragm and a light shielding plate for preventing flare are provided between the first lens 81 and the second lens 82. The object-side convex surface of the first lens 81 and the object-side concave surface of the third lens 83 are aspheric surfaces. Table 8 below shows lens data and aspheric coefficients of the taking lens 80.

The specification of the taking lens 80 is
f = 26.00mm
f1 = 132.75mm
f2 = 14.06mm
f3 = −17.10 mm
f23 = 29.31 mm
Fno = 3.5
2ω = 81.4 °
L = 29.11mm
Pz = −0.351
fb (30 degrees) = 0.000
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 14.06 / −17.10 | = 0.820
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (29.31 / 26) = 1.13
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0.06 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (-17.10 / 26) = 0.541
It is. FIG. 16 shows aberration diagrams of the taking lens 80. In this embodiment, the image surface is flat.

Example 9
In FIG. 17, the photographing lens 90 according to the ninth example includes a first lens 91 having a positive power, a second lens 92 having a positive power, and a third lens 93 having a negative power in order from the object side. The first lens 91 is a positive meniscus lens having a convex surface facing the object side, and the second lens 92 is a biconvex lens in which the curvature of the convex surface on the object side is loose and the curvature of the convex surface on the image side is increased. The lens 93 is a plano-concave negative lens having a concave surface on the object side and a flat surface on the image side. The first lens 91 and the third lens 93 are made of optical resin, and the second lens 92 is made of optical glass. A diaphragm is provided between the first lens 91 and the second lens 92. The object side convex surface of the first lens 91 and the object side concave surface of the third lens 93 are aspherical surfaces, respectively. Table 9 below shows lens data and aspheric coefficients of the photographing lens 90.

The specification of the taking lens 90 is
f = 26.00mm
f1 = 136.99mm
f2 = 15.10mm
f3 = -22.00mm
f23 = 28.22 mm
Fno = 4.02
2ω = 82.0 °
L = 30.05mm
Pz = −0.414
fb (30 degrees) = − 0.017 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 15.10 / -22.00 | = 0.686
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (28.22 / 26) = 1.085
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is clear that the first lens 91 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (15.10 / 26) = 0.581
And conditional expression (6) is satisfied. FIG. 18 is an aberration diagram of the taking lens 90. In this example, the image surface (film surface) is curved with a curvature radius of −150 mm in the horizontal direction, and the aberration diagram based on the converted curvature radius (−220.0 mm) converted in the diagonal direction. Is shown.

(Example 10)
In FIG. 19, the photographing lens 100 according to the tenth embodiment includes a first lens 101 having a positive power, a second lens 102 having a positive power, and a third lens 103 having a negative power in order from the object side. The first lens 101 is a positive meniscus lens having a convex surface facing the object side. The second lens 102 is a biconvex lens having a gentle curvature on the object side surface and a strong curvature on the image side surface. Reference numeral 103 denotes a negative meniscus lens having a concave surface facing the object side. The first lens 101 and the third lens 103 are made of optical resin, and the second lens 102 is made of optical glass. A diaphragm is provided between the first lens 101 and the second lens 102. The object side convex surface of the first lens 101 and the object side concave surface of the third lens 103 are aspherical surfaces, respectively. Table 10 below shows lens data and aspheric coefficients of the taking lens 100.

The specification of the taking lens 100 is
f = 26.00mm
f1 = 84.57mm
f2 = 13.37mm
f3 = -14.95 mm
f23 = 34.62mm
Fno = 4.03
2ω = 80.0 °
L = 29.02 mm
Pz = −0.230
fb (30 degrees) = − 0.024 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 13.37 / -14.95 | = 0.894
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (34.62 / 26) = 1.33
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is clear that the first lens 101 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (13.37 / 26) = 0.514
And conditional expression (6) is satisfied. FIG. 6 is an aberration diagram of the taking lens 100.

(Example 11)
In FIG. 21, the photographic lens 110 according to the eleventh embodiment includes a first lens 111 having a positive power, a second lens 112 having a positive power, a third lens 113 having a negative power, and a plane parallel plate 114 in order from the object side. It consists of. The first lens 111 is a positive meniscus lens having a convex surface facing the object side, and the second lens 112 is a biconvex lens having a gentle curvature on the object side convex surface and a strong curvature on the image side convex surface, and the third lens 113. Is a negative meniscus lens having a concave surface facing the object side. The first lens 111 and the third lens 113 are made of optical resin, and the second lens 112 is made of optical glass. The object side convex surface of the first lens 111 and the object side concave surface of the third lens 113 are aspherical surfaces, respectively. Table 11 below shows lens data and aspherical coefficients of the taking lens 110.

The specification of the taking lens 110 is
f = 15.00mm
f1 = 46.78mm
f2 = 7.09mm
f3 = −8.17 mm
f23 = 19.71mm
Fno = 3.5
2ω = 70.0 °
L = 17.48mm
Pz = −0.146
fb (30 degrees) = − 0.022 mm
It is.

The ratio between f2 and f3, which is the characteristic value of conditional expression (1), is
| F2 / f3 | = | 7.09 / −8.17 | = 0.868
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (19.71 / 15) = 1.31
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is clear that the first lens 111 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (7.09 / 15) = 0.473
And conditional expression (6) is satisfied. FIG. 22 is an aberration diagram of the taking lens 110. In this embodiment, the image surface is flat.

(Example 12)
In FIG. 23, the photographing lens 120 includes a first lens 121 having a positive power, a second lens 122 having a positive power, and a third lens 123 having a negative power in order from the object side. The first lens 121 is a positive meniscus lens having a convex surface facing the object side, and the second lens 122 is a biconvex lens having a gentle curvature of the object side convex surface and a strong curvature of the image side convex surface, and the third lens 123. Is a negative meniscus lens having a concave surface facing the object side. The first lens 121 and the third lens 123 are made of optical resin, and the second lens 122 is made of optical glass. A diaphragm is provided between the first lens 121 and the second lens 122. The object side convex surface of the first lens 121 and the object side concave surface of the third lens 123 are aspherical surfaces, respectively. Table 12 below shows lens data and aspheric coefficients of the taking lens 120.

撮影レンズ１２０の仕様は、
ｆ＝２６．００ｍｍ
ｆ１＝１２６．６８ｍｍ
ｆ２＝１４．５０ｍｍ
ｆ３＝−１７．８３ｍｍ
ｆ２３＝２９．６６ｍｍ
Ｆｎｏ＝４．０３
２ω＝８１．０°
Ｌ＝２８．９７ｍｍ
Ｐｚ＝−０．２４４
ｆｂ（３０度）＝−０．０１６ｍｍ
である。

The specification of the taking lens 120 is
f = 26.00mm
f1 = 126.68mm
f2 = 14.50mm
f3 = -17.83 mm
f23 = 29.66mm
Fno = 4.03
2ω = 81.0 °
L = 28.97mm
Pz = −0.244
fb (30 degrees) = − 0.016 mm
It is.

For conditional expression (1),
| F2 / f3 | = | 14.50 / -17.83 | = 0.814
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (29.66 / 26) = 1.14
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is clear that the first lens 121 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (14.50 / 26) = 0.558
And satisfies the conditional expression (6). FIG. 24 is an aberration diagram of the taking lens 120. In this embodiment, the image surface is flat.

(Example 13)
In FIG. 25, the photographing lens 130 includes a first lens 131 having a positive power, a second lens 132 having a positive power, and a third lens 133 having a negative power in order from the object side. The first lens 131 is a positive meniscus lens having a convex surface facing the object side, and the second lens 132 is a biconvex lens having a gentle curvature on the object side convex surface and a strong curvature on the image side convex surface, and the third lens 133. Is a negative meniscus lens having a concave surface facing the object side. The first lens 131 and the third lens 133 are made of optical resin, and the second lens 132 is made of optical glass. A diaphragm is provided between the first lens 131 and the second lens 132. The object side convex surface of the first lens 131 and the object side concave surface of the third lens 133 are aspherical surfaces, respectively. Table 13 below shows lens data and aspheric coefficients of the taking lens 130.

The specification of the taking lens 130 is
f = 26.00mm
f1 = 59.42mm
f2 = 20.797mm
f3 = -32.214mm
f23 = 41.02mm
Fno = 4.03
2ω = 81.0 °
L = 29.9mm
Pz = −0.494
fb (30 degrees) = 0.038 mm
It is.

For conditional expression (1),
| F2 / f3 | = | 20.797 / -32.214 | = 0.646
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (41.02 / 26) = 1.58
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is obvious that the first lens 131 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (20.797 / 26) = 0.8
And conditional expression (6) is satisfied. FIG. 26 is an aberration diagram of the taking lens 130. In this example, the image surface (film surface) is curved with a curvature radius of −200 mm in the horizontal direction, and an aberration diagram based on the converted curvature radius (−289 mm) converted in the diagonal direction is shown. ing.

(Example 14)
In FIG. 27, the photographic lens 140 according to the fourteenth embodiment includes a first lens 141 having a positive power, a second lens 142 having a positive power, and a third lens 143 having a negative power in order from the object side. The first lens 141 is a positive meniscus lens having a convex surface facing the object side, and the second lens 142 is a biconvex lens having a gentle curvature of the object side convex surface and a strong curvature of the image side convex surface, and the third lens 143. Is a negative meniscus lens having a concave surface facing the object side. The first lens 141 and the third lens 143 are made of optical resin, and the second lens 142 is made of optical glass. A diaphragm is provided between the first lens 141 and the second lens 142. The object side convex surface of the first lens 141 and the object side concave surface of the third lens 143 are aspherical surfaces, respectively. Table 14 below shows lens data and aspheric coefficients of the photographing lens 140.

The specification of the taking lens 140 is
f = 26.00mm
f1 = 66.81mm
f2 = 18.20mm
f3 = −25.15 mm
f23 = 38.69mm
Fno = 4.03
2ω = 81.0 °
L = 29.01 mm
Pz = −0.369
fb (30 degrees) = 0.025 mm
It is.

For conditional expression (1),
| F2 / f3 | = | 18.20 / −25.15 | = 0.724
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (38.69 / 26) = 1.49
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). Regarding conditional expression (5), it is obvious that the first lens 141 is a positive lens and has a positive refractive power. For conditional expression (6),
f2 / f = (18.20 / 26) = 0.70
And conditional expression (6) is satisfied. FIG. 28 shows aberration diagrams of the taking lens 140. Note that the image plane of the photographing lens 140 is flat.

(Example 15)
In FIG. 29, the photographing lens 150 according to the fifteenth embodiment includes a first lens 151 having a positive power, a second lens 152 having a positive power, and a third lens 153 having a negative power in order from the object side. The first lens 151 is a positive meniscus lens having a convex surface facing the object side, the second lens 152 is a biconvex lens having a gentle curvature on the object side convex surface and a strong curvature on the image side convex surface, and a third lens 153. Is a negative meniscus lens having a concave surface facing the object side. In the photographic lens 150, all of the first lens 151 to the third lens 153 are made of optical glass. A diaphragm is provided between the first lens 151 and the second lens 152. The object side convex surface of the first lens 151 and the object side concave surface of the third lens 153 are aspherical surfaces, respectively. Table 15 below shows lens data and aspheric coefficients of the photographing lens 150.

The specification of the taking lens 150 is
f = 26.00mm
f1 = 81.81mm
f2 = 18.20mm
f3 = −28.14 mm
f23 = 33.57mm
Fno = 4.03
2ω = 81.0 °
L = 29.11mm
Pz = −0.38
fb (30 degrees) = 0.00 mm
It is.

For conditional expression (1),
| F2 / f3 | = | 18.20 / −28.14 | = 0.647
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (33.57 / 26) = 1.29
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = | 1.620-1.720 | = 0.10 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (18.20 / 26) = 0.70
It is. FIG. 30 is an aberration diagram of the taking lens 150.

In the photographing lenses 80 to 150 according to Examples 8 to 15, the focal length f2 of the second lens and the combined focal length f of the entire system are 0.42 <f2 / f <0.9.
Meet. Also, when the powers of the first lens, the second lens, and the third lens are P1, P2, and P3, respectively,
P1 <| P3 | <P2
Satisfied.

(Example 16)
In FIG. 31, the photographing lens 160 includes a first lens 161 having a positive power, a second lens 162 having a positive power, and a third lens 163 having a negative power in order from the object side. The first lens 161 has a convex meniscus shape with a convex surface facing the object side, the second lens 162 has a biconvex shape with a strong curvature of the image-side convex surface, and the third lens 163 has an object-side concave surface Has a biconcave shape with a small curvature radius. All the lenses of the first lens 161 to the third lens 163 are made of polymethyl methacrylate (acrylic) resin (PMMA resin). A diaphragm is provided between the first lens 161 and the second lens 162. The image surface side concave surface of the first lens 161, the image surface side convex surface of the second lens 162, and the object side concave surface of the third lens 163 are each formed as an aspheric surface. Table 16 shows lens data and aspheric coefficients of the taking lens 160.

The specification of the photographic lens 160 is
f = 25.00mm
f1 = 87.42mm
f2 = 11.99mm
f3 = -14.17mm
f23 = 31.1mm
Fno = 4.00
2ω = 84.00 °
L = 28.93mm
It is.

For conditional expression (1),
| F2 / f3 | = | 11.99 / −14.17 | = 0.846
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (31.1 / 25) = 1.24
And satisfies the conditional expression (2). For conditional expression (4),
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (11.99 / 25) = 0.480
It is. FIG. 32 shows aberration diagrams of the taking lens 160. FIG. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 17)
In FIG. 33, the photographing lens 170 includes a first lens 171 having a positive power, a second lens 172 having a positive power, and a third lens 173 having a negative power in order from the object side. The first lens 171 has a convex meniscus shape with a convex surface facing the object side, the second lens 172 has a biconvex shape with a small curvature radius of the image side convex surface, and the third lens 173 has an object side The concave surface has a biconcave shape having a small radius of curvature. The first lens 171 to the third lens 173 are all made of PMMA resin. A diaphragm is provided between the first lens 171 and the second lens 172. The image side concave surface of the first lens 171, the image side convex surface of the second lens 172, and the object side concave surface of the third lens 173 are each formed as an aspherical surface. Table 17 below shows lens data and aspherical coefficients of the taking lens 170.

The specification of the photographic lens 170 is
f = 25.00mm
f1 = 95.28mm
f2 = 12.16mm
f3 = -13.75 mm
f23 = 30.32mm
Fno = 4.00
2ω = 84.00 °
L = 28.94mm
It is.

For conditional expression (1),
| F2 / f3 | = | 12.16 / -13.75 | = 0.848
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (30.32 / 25) = 1.21
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same optical resin,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (12.16 / 25) = 0.486
It is. FIG. 34 shows aberration diagrams of the photographing lens 170. FIG. In this embodiment, the image surface is flat.

(Example 18)
In FIG. 35, the taking lens 180 includes a first lens 181 having a positive power, a second lens 182 having a positive power, and a third lens 183 having a negative power in order from the object side. The first lens 181 has a convex meniscus shape with the convex surface facing the object side, the second lens 182 has a biconvex shape with a small curvature radius of the image side convex surface, and the third lens 183 has an object side The concave surface has a biconcave shape with a small radius of curvature. The first lens 181 to the third lens 183 are all made of PMMA resin. A diaphragm is provided between the first lens 181 and the second lens 182. The object-side convex surface of the first lens 181, the image-side convex surface of the second lens 182, and the object-side concave surface of the third lens 183 are each formed as an aspheric surface. Table 18 below shows lens data and aspheric coefficients of the taking lens 180.

The specification of the taking lens 180 is
f = 26.00mm
f1 = 72.03mm
f2 = 12.58mm
f3 = -13.76 mm
Fno = 4.00
2ω = 83 °
L = 29.14mm
It is.

For conditional expression (1),
| F2 / f3 | = | 12.58 / −13.76 | = 0.914
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (38.2 / 26) = 1.47
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (12.58 / 26) = 0.484
It is. FIG. 36 shows aberration diagrams of the taking lens 180. FIG. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 19)
In FIG. 37, the taking lens 190 includes a first lens 191 having a positive power, a second lens 192 having a positive power, and a third lens 193 having a negative power in order from the object side. The first lens 191 has a convex meniscus shape with a convex surface facing the object side, the second lens 192 has a biconvex shape with a small curvature radius of the image side convex surface, and the third lens 193 has an object side It has a concave meniscus shape with the concave surface facing the surface. The first lens 191 to the third lens 193 are all made of PMMA resin. A diaphragm is provided between the first lens 191 and the second lens 192. The object-side convex surface of the first lens 191, the image-side convex surface of the second lens 192, and the image-side convex surface of the third lens 193 are each formed as an aspheric surface. Table 19 below shows lens data and aspherical coefficients of the photographing lens 190.

The specification of the taking lens 190 is
f = 26.00mm
f1 = 85.63mm
f2 = 15.80 mm
f3 = −19.32 mm
f23 = 36.64mm
Fno = 4.00
2ω = 85 °
L = 28.84mm
It is.

For conditional expression (1),
| F2 / f3 | = | 15.80 / −19.32 | = 0.818
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (36.64 / 26) = 1.41
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (15.8 / 26) = 0.608
It is. FIG. 38 shows aberration diagrams of the photographing lens 190. Each aberration diagram is based on a converted curvature radius (-149 mm) obtained by converting an image surface (film surface) curved with a curvature radius of -100 mm in the horizontal direction (longitudinal direction of the film surface) in a diagonal direction. It is represented by.

(Example 20)
In FIG. 39, the photographing lens 200 includes a first lens 201 having a positive power, a second lens 202 having a positive power, and a third lens 203 having a negative power in order from the object side. The first lens 201 has a convex meniscus shape with a convex surface facing the object side, the second lens 202 has a biconvex shape with a small radius of curvature of the image side curved surface, and the third lens 203 has an object side The concave surface has a biconcave shape having a small radius of curvature. The first lens 201 to the third lens 203 are all made of PMMA resin. A diaphragm is provided between the first lens 201 and the second lens 202. The object-side convex surface of the first lens 201, the image-side convex surface of the second lens 202, and the object-side concave surface of the third lens 203 are each formed as an aspheric surface. Table 20 below shows lens data and aspheric coefficients of the taking lens 200.

The specification of the taking lens 200 is
f = 26.00mm
f1 = 75.94mm
f2 = 11.66mm
f3 = -12.19mm
f23 = 36.83mm
Fno = 4.00
2ω = 81.4 °
L = 28.55mm
It is.

For conditional expression (1),
| F2 / f3 | = | 11.66 / -12.19 | = 0.957
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (36.83 / 26) = 1.42
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same resin material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (11.66 / 26) = 0.448
It is. FIG. 40 shows aberration diagrams of the photographing lens 200. FIG. The image plane of the present embodiment is flat.

(Example 21)
In FIG. 41, the photographing lens 210 includes a first lens 211 having a positive power, a second lens 212 having a positive power, and a third lens 213 having a negative power in order from the object side. The first lens 211 has a convex meniscus shape with a convex surface facing the object side, the second lens 212 has a biconvex shape with a small curvature radius of the image surface side convex surface, and the third lens 203 has an object side The concave surface has a biconcave shape having a small radius of curvature. The first lens 211 to the third lens 213 are all made of PMMA resin. A diaphragm is provided between the first lens 211 and the second lens 212. The object-side convex surface of the first lens 211, the image-side convex surface of the second lens 212, and the object-side concave surface of the third lens 213 are each formed as an aspheric surface. Table 21 below shows lens data and aspheric coefficients of the taking lens 210.

The specification of the taking lens 210 is
f = 26.00mm
f1 = 268.65mm
f2 = 10.00mm
f3 = -11.98 mm
f23 = 24.12 mm
Fno = 4.00
2ω = 83 °
L = 30.47mm
It is.

For conditional expression (1),
| F2 / f3 | = | 10.00 / -11.98 | = 0.835
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (24.12 / 26) = 0.93
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (10.00 / 26) = 0.385
It is. FIG. 42 shows aberration diagrams of the taking lens 210. FIG. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) curved in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by

(Example 22)
In FIG. 43, the photographing lens 220 includes a first lens 221 having a positive power, a second lens 222 having a positive power, and a third lens 223 having a negative power in order from the object side. The first lens 221 has a convex meniscus shape with a convex surface facing the object side, the second lens 222 has a biconvex shape with a small curvature radius of the image surface side convex surface, and the third lens 223 has an object side The concave surface has a biconcave shape having a small radius of curvature. The first lens 221 to the third lens 223 are all made of PMMA resin. A diaphragm is provided between the first lens 221 and the second lens 222. The object-side convex surface of the first lens 221, the image-side convex surface of the second lens 222, and the object-side concave surface of the third lens 223 are each formed as an aspheric surface. Table 22 below shows lens data and aspheric coefficients of the photographing lens 220.

The specification value of the taking lens 220 is
f = 26.00mm
f1 = 77.12mm
f2 = 13.99mm
f3 = -15.17 mm
Fno = 4.03
2ω = 82 °
L = 28.92mm
It is.

For conditional expression (1),
| F2 / f3 | = | 13.99 / −15.17 | = 0.922
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (37.88 / 26) = 1.46
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (13.99 / 26) = 0.608
It is. FIG. 44 shows aberration diagrams of the photographing lens 220. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 23)
In FIG. 45, the taking lens 230 includes a first lens 231 having a positive power, a second lens 232 having a positive power, and a third lens 233 having a negative power in order from the object side. The first lens 231 has a convex meniscus shape with a convex surface facing the object side, and the second lens 232 has a plano-convex shape with a flat surface on the object side and a convex surface facing the image surface side, and a third lens 233 has a biconcave shape in which the radius of curvature of the object-side concave surface is small. The first lens 231 to the third lens 233 are all made of PMMA resin. A diaphragm is provided between the first lens 231 and the second lens 232. The object-side convex surface of the first lens 231, the image-side convex surface of the second lens 232, and the object-side concave surface of the third lens 233 are each formed as an aspheric surface. Table 23 below shows lens data and aspheric coefficients of the taking lens 230.

The specification of the taking lens 230 is
f = 26.00mm
f1 = 90.98mm
f2 = 17.00mm
f3 = −24.64 mm
f23 = 32.66 mm
Fno = 4.03
2ω = 82 °
L = 29.46mm
It is.

For conditional expression (1),
| F2 / f3 | = | 17.00 / −24.64 | = 0.690
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (32.66 / 26) = 1.26
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (17.00 / 26) = 0.654
It is. FIG. 46 shows aberration diagrams of the taking lens 230. FIG. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 24)
In FIG. 47, the photographic lens 240 includes a first lens 241 having a positive power, a second lens 242 having a positive power, and a third lens 243 having a negative power in order from the object side. The first lens 241 has a convex meniscus shape with the convex surface facing the object side, the second lens 242 has a biconvex shape with a small curvature radius of the image side convex surface, and the third lens 243 has an object side It has a concave meniscus shape with a concave surface facing the surface. The first lens 241 to the third lens 243 are all made of PMMA resin. A diaphragm is provided between the first lens 241 and the second lens 242. The object-side convex surface of the first lens 241, the object-side convex surface of the second lens 242, and the object-side concave surface of the third lens 243 are each formed as an aspheric surface. Table 24 below shows lens data and aspherical coefficients of the taking lens 240.

The specification of the taking lens 240 is
f = 26.00mm
f1 = 74.19mm
f2 = 14.61mm
f3 = -15.49 mm
f23 = 41.01mm
Fno = 4.00
2ω = 83 °
L = 28.38mm
It is.

For conditional expression (1),
| F2 / f3 | = | 14.61 / -15.49 | = 0.944
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (41.01 / 26) = 1.58
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (14.61 / 26) = 0.562
It is. FIG. 48 is an aberration diagram of the taking lens 240. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 25)
49, the photographing lens 250 includes a first lens 251 having a positive power, a second lens 252 having a positive power, and a third lens 253 having a negative power in order from the object side. The first lens 251 has a convex meniscus shape with a convex surface facing the object side, the second lens 252 has a biconvex shape with a small curvature radius of the image side convex surface, and the third lens 253 has an object side It has a concave meniscus shape with a concave surface facing the surface. The first lens 251 to the third lens 253 are all made of PMMA resin. A diaphragm is provided between the first lens 251 and the second lens 252. The object-side convex surface of the first lens 251 and the image-side convex surface of the second lens 252 are each formed as an aspheric surface. Table 25 below shows lens data and aspheric coefficients of the photographing lens 250.

The specification value of the taking lens 250 is
f = 26.00mm
f1 = 183.89mm
f2 = 15.28 mm
f3 = -19.22 mm
f23 = 28.05mm
Fno = 4.03
2ω = 81 °
L = 28.66mm
It is.

For conditional expression (1),
| F2 / f3 | = | 15.28 / -19.22 | = 0.895
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (28.05 / 26) = 1.08
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (15.28 / 26) = 0.588
It is. FIG. 50 is an aberration diagram of the taking lens 250. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

In addition, in the photographing lenses 160 to 250 according to Examples 16 to 25, the focal length f2 of the second lens and the combined focal length f of the entire system are 0.35 <f2 / f <0.7.
Meet.

(Example 26)
In FIG. 51, the photographing lens 260 includes a first lens 261 having a positive power, a second lens 262 having a positive power, and a third lens 263 having a negative power in order from the object side. The first lens 261 has a convex meniscus shape with a convex surface facing the object side, the second lens 262 has a biconvex shape with a small curvature radius of the image surface side convex surface, and the third lens 263 has an object side Has a biconcave shape having a concave surface with a small radius of curvature. The first lens 261 to the third lens 263 are all made of PMMA resin. A diaphragm is provided between the first lens 261 and the second lens 262. The object-side convex surface of the first lens 261, the image-side convex surface of the second lens 262, and the object-side concave surface of the third lens 263 are each formed as an aspheric surface. Table 26 below shows lens data and aspherical coefficients of the photographing lens 260.

The specification of the photographic lens 260 is
f = 26.00mm
f1 = 438.09mm
f2 = 12.73mm
f3 = -18.11mm
f23 = 24.9mm
Fno = 4.00
2ω = 82 °
L = 30.68mm
It is.

For conditional expression (1),
| F2 / f3 | = | 12.73 / −18.11 | = 0.703
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (24.9 / 26) = 0.96
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (12.73 / 26) = 0.49
It is. FIG. 52 is an aberration diagram of the photographing lens 260. Each aberration diagram is based on a converted curvature radius (−220 mm) obtained by converting an image surface (film surface) curved in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −150 mm in a diagonal direction. It is represented by.

(Example 27)
In FIG. 53, the photographing lens 270 includes a first lens 271 having a negative power, a second lens 272 having a positive power, and a third lens 273 having a negative power in order from the object side. The first lens 271 has a concave meniscus shape with the concave surface facing the image surface side, the second lens 272 has a biconvex shape with a small curvature radius of the image surface side convex surface, and the third lens 273 has an object It has a biconcave shape having a concave surface with a small radius of curvature on the side. The first lens 271 to the third lens 273 are all made of PMMA resin. A diaphragm is provided between the first lens 271 and the second lens 272. The object side convex surface of the first lens 271, the image side convex surface of the second lens 272, and the object side concave surface of the third lens 273 are each formed as an aspheric surface. Table 27 below shows lens data and aspherical coefficients of the taking lens 270.

The specification of the taking lens 270 is
f = 26.00mm
f1 = -150.00mm
f2 = 12.14mm
f3 = -19.05 mm
f23 = 20.17mm
Fno = 4.00
2ω = 81 °
L = 31.46mm
It is.

For conditional expression (1),
| F2 / f3 | = | 12.14 / -19.05 | = 0.637
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (20.17 / 26) = 0.78
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (12.14 / 26) = 0.47
It is. FIG. 54 shows aberration diagrams of the taking lens 270. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 28)
55, the photographing lens 280 includes a negative power first lens 281, a positive power second lens 282, and a negative power third lens 283 in order from the object side. The first lens 281 has a concave meniscus shape with the concave surface facing the image surface side, the second lens 282 has a biconvex shape with a small radius of curvature of the image surface side convex surface, and the third lens 283 is an object. It has a biconcave shape having a concave surface with a small radius of curvature on the side. The first lens 281 to the third lens 283 are all made of PMMA resin. A diaphragm is provided between the first lens 281 and the second lens 282. The object-side convex surface of the first lens 281, the image-side convex surface of the second lens 282, and the object-side concave surface of the third lens 283 are each formed as an aspheric surface. Table 28 below shows lens data and aspheric coefficients of the taking lens 280.

The specifications of the taking lens 280 are:
f = 26.00mm
f1 = −100.00 mm
f2 = 11.99mm
f3 = -20.33mm
f23 = 18.87 mm
Fno = 4.00
2ω = 81 °
L = 32.05mm
It is.

For conditional expression (1),
| F2 / f3 | = | 11.99 / -20.33 | = 0.590
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (18.87 / 26) = 0.73
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (11.99 / 26) = 0.46
It is. FIG. 56 shows aberration diagrams of the taking lens 280. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

(Example 29)
In FIG. 57, the photographing lens 290 includes a first lens 291 having a negative power, a second lens 292 having a positive power, and a third lens 293 having a negative power in order from the object side. The first lens 291 has a concave meniscus shape with the concave surface facing the image surface side, the second lens 292 is a biconvex lens having a convex surface with a small radius of curvature on the image surface side, and the third lens 293 is an object. This is a biconcave lens with a small curvature radius on the side. The first lens 291 to the third lens 293 are all made of PMMA resin. A diaphragm is provided between the first lens 291 and the second lens 292. The object-side convex surface of the first lens 291, the image-side convex surface of the second lens 292, and the object-side concave surface of the third lens 243 are each formed as an aspheric surface. Table 29 below shows lens data and aspheric coefficients of the taking lens 290.

The specifications of the taking lens 290 are:
f = 26.00mm
f1 = −50.00mm
f2 = 11.80 mm
f3 = −24.69 mm
f23 = 16.38 mm
Fno = 4.00
2ω = 81 °
L = 33.55mm
It is.

For conditional expression (1),
| F2 / f3 | = | 11.80 / −24.69 | = 0.478
Thus, the conditional expression (1) is satisfied. For conditional expression (2),
f23 / f = (16.38 / 26) = 0.63
And satisfies the conditional expression (2). As for conditional expression (4), as can be seen from the fact that all lenses are made of the same material,
| N1-N3 | = 0 <0.13
And satisfies the conditional expression (4). In addition,
f2 / f = (11.80 / 26) = 0.45
It is. FIG. 58 shows aberration diagrams of the taking lens 290. Each aberration diagram is based on a converted curvature radius (−299 mm) obtained by converting an image surface (film surface) bent in a horizontal direction (longitudinal direction of the film surface) with a curvature radius of −200 mm in a diagonal direction. It is represented by.

It is sectional drawing which shows the lens structure of 1st Example. It is an aberration diagram of the first example. It is sectional drawing which shows the lens structure of 2nd Example. It is an aberration diagram of the second example. It is sectional drawing which shows the lens structure of 3rd Example. It is an aberration diagram of the third example. It is sectional drawing which shows the lens structure of 4th Example. It is an aberration diagram of the fourth example. It is sectional drawing which shows the lens structure of 5th Example. It is an aberration diagram of the fifth example. It is sectional drawing which shows the lens structure of 6th Example. It is an aberration diagram of the sixth example. It is sectional drawing which shows the lens structure of 7th Example. It is an aberration diagram of the seventh example. It is sectional drawing which shows the lens structure of 8th Example. It is an aberration diagram of the eighth example. It is sectional drawing which shows the lens structure of 9th Example. It is an aberration diagram of the ninth example. It is sectional drawing which shows the lens structure of 10th Example. It is an aberration diagram of the tenth example. It is sectional drawing which shows the lens structure of 11th Example. It is an aberration diagram of the eleventh example. It is sectional drawing which shows the lens structure of 12th Example. It is an aberration diagram of the twelfth example. It is sectional drawing which shows the lens structure of 13th Example. It is an aberration diagram of the 13th example. It is sectional drawing which shows the lens structure of 14th Example. It is an aberration diagram of the 14th example. It is sectional drawing which shows the lens structure of 15th Example. It is an aberration diagram of the 15th example. It is sectional drawing which shows the lens structure of 16th Example. It is an aberration diagram of Example 16. It is sectional drawing which shows the lens structure of 17th Example. It is an aberration diagram of the 17th example. It is sectional drawing which shows the lens structure of 18th Example. It is an aberration diagram of the 18th example. It is sectional drawing which shows the lens structure of 19th Example. It is an aberration diagram of the 19th example. It is sectional drawing which shows the lens structure of 20th Example. It is an aberration diagram of the twentieth example. It is sectional drawing which shows the lens structure of 21st Example. FIG. 34 is an aberration diagram of Example 21. It is sectional drawing which shows the lens structure of 22nd Example. It is an aberration diagram of the 22nd example. It is sectional drawing which shows the lens structure of 23rd Example. It is an aberration diagram of the 23rd example. It is sectional drawing which shows the lens structure of 24th Example. It is an aberration diagram of the 24th example. It is sectional drawing which shows the lens structure of 25th Example. It is an aberration diagram of the 25th example. It is sectional drawing which shows the lens structure of 26th Example. It is an aberration diagram of the 26th example. It is sectional drawing which shows the lens structure of 27th Example. It is an aberration diagram of the 27th example. It is sectional drawing which shows the lens structure of 28th Example. FIG. 42 is an aberration diagram of Example 28. It is sectional drawing which shows the lens structure of 29th Example. FIG. 42 is an aberration diagram of Example 29.

Explanation of symbols

10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290 Photography lenses 11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211 , 221, 231, 241, 251, 261, 271, 281, 291 First lens 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162 , 172,182,192,202,212,222,232,242,252,262,272,282,292 13, 23, 33, 43, 53, 63, 73, 83, 93, 103, 113, 123, 133, 143, 153, 163, 173, 183, 193, 203, 213, 223, 233, 243, 253 , 263, 273, 283, 293 Third lens

Claims (10)

In order from the object side, the lens is composed of a first lens having a convex surface facing the object side and at least one surface being aspherical, a second lens having a positive power, and a third lens having a negative power having a concave surface facing the object side. A photographing lens satisfying the following conditional expression:
(1) 0.49 <| f2 / f3 | <1.0
(2) 0.5 <f23 / f <4
Here, f is the combined focal length of the entire system, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f23 is the combined focal length of the second lens and the third lens. 2. The photographic lens according to claim 1, wherein the second lens includes a plano-convex lens having a convex surface facing the image side or a positive meniscus lens having a convex surface facing the image side, and satisfies the following conditional expression.
(3) N1 <N3
N1 is the refractive index of the first lens, and N3 is the refractive index of the third lens. 2. The photographing according to claim 1, wherein the second lens includes a biconvex lens having a convex surface having a small curvature radius on the image side or a plano-convex lens having a convex surface facing the image side, and satisfies the following conditional expression: lens.
(4) | N1-N3 | <0.13
N1 is the refractive index of the first lens, and N3 is the refractive index of the third lens.   4. A photographic lens according to claim 2, wherein at least one surface of the third lens is an aspherical surface. 5. The photographing lens according to claim 4, wherein the first lens and the third lens are made of resin, the second lens is made of glass, and the following conditions are satisfied.
(5) p1 ≧ 0
(6) 0.35 <f2 / f <0.9
Here, p1 is the refractive power of the first lens, f is the combined focal length of the entire lens system, and f2 is the focal length of the second lens.   5. The photographing lens according to claim 4, wherein the first lens and the third lens are aspheric glass lenses.   2. The photographic lens according to claim 1, wherein the second lens includes a biconvex lens having a convex surface having a small curvature radius on the image side, and the first lens to the third lens are made of the same material.   The photographing lens according to claim 7, wherein at least one surface of the second lens is an aspherical surface.   The taking lens according to claim 2, 3 or 7, wherein at least one surface of the second lens and the third lens is an aspherical surface. 8. The photographing lens according to claim 2, wherein the first, second, and third lenses are resin lenses.

Images