JP4590900B2 - Shooting lens - Google Patents

Description

  The present invention relates to a photographic lens, and more particularly to a photographic lens capable of focusing from an infinitely distant object to a close object near the same magnification.

  2. Description of the Related Art Conventionally, in a photographic camera, a still video camera, or the like, there is a so-called macro lens or a micro lens (hereinafter referred to as “macro lens”) as a photographing lens for photographing a short distance object. Such a macro lens is designed so as to obtain a high optical performance particularly when photographing a short distance object as compared with a general photographing lens. Of course, many macro lenses can shoot not only short-distance objects but also short-distance objects to infinity objects.

In general, with a photographic lens, as the photographic distance becomes shorter and the photographic magnification becomes higher, fluctuations in aberration become larger and it becomes difficult to correct this well. For this reason, a so-called floating lens has been proposed in which a plurality of lens groups are independently moved during focusing to correct near-field fluctuations in aberrations (see, for example, Patent Documents 1 and 2).
Registration No. 2679130 JP 2002-90622 A

  However, the floating lens disclosed in Patent Document 1 has a configuration in which a large, large lens group is moved greatly during focusing. Therefore, when the floating lens is applied to an autofocus camera that performs focusing using a motor or the like, there is a problem that quick focusing cannot be performed.

  In addition, the floating lens disclosed in Patent Document 2 is configured to reduce the amount of movement of the first lens group in consideration of autofocus. However, there is a problem that the effect is not sufficient because the structure is such that the large and large lens group is moved as in the above-mentioned Patent Document 1.

  Therefore, the present invention has been made in view of the above problems, and it is possible to quickly perform focusing from an infinitely distant object to a close object near the same magnification by moving a lightweight lens group, and it is favorable over the entire focusing area. An object is to provide a photographing lens having image performance.

In order to solve the above problems, the present invention
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power A group and a fifth lens group having negative refractive power ,
During focusing from an infinite object to a close object, the first lens group is fixed, the second lens group moves to the image side, the third lens group moves to the object side, and the fourth lens group moves toward the object side in a different trajectory and the third lens group, the fifth lens group Ri fixed der,
A photographic lens characterized by satisfying the following conditional expression is provided.
0.89 ≦ f4 / f3 <2.0
f3: focal length of the third lens group
f4: focal length of the fourth lens group

  According to the present invention, it is possible to quickly perform focusing from an object at infinity to an object at a near distance near the same magnification by moving a lightweight lens group, and to provide a photographing lens having good image performance over the entire focusing area. Can do.

  The photographic lens of the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive lens in order from the object side. It has a fourth lens group having refractive power and a fifth lens group having negative refractive power. In the photographing lens of the present invention, the first lens group is fixed, the second lens group moves to the image side, and the third lens group moves to the object side during focusing from an object at infinity to a near object. The fourth lens group is moved to the object side along a different locus from the third lens group, and the fifth lens group is fixed.

  As described above, the photographic lens of the present invention, unlike the conventional macro lens, secures the photographic magnification by fixing the heavy first lens group and sharing it with a plurality of lens groups after the relatively light second lens group, Focusing is performed by reducing the amount of movement of the moving lens group. Thereby, the photographing lens of the present invention can perform quick autofocus and good aberration correction. In addition, when the focusing is performed, the third lens group and the fourth lens group move along different trajectories, so that the variation in field curvature can be minimized.

  According to a preferred aspect of the present invention, an aperture stop is provided between the second lens group and the third lens group, and the aperture stop is fixed when focusing from an object at infinity to a close object. It is desirable. Thereby, the photographic lens of the present invention can simplify the structure of the mechanical part.

According to a preferred aspect of the present invention, it is desirable that the aperture diameter of the aperture stop be small when focusing from an infinitely distant object to a close object.
When the diameter of the first lens group is determined by land rays (RAND rays) at the time of focusing on an object at infinity, the diameter of the aperture stop is smaller at the time of focusing at a short distance than at the time of focusing on an object at infinity. For this reason, it is necessary to change the aperture diameter of the aperture stop according to the photographing distance. Here, the land light beam is a light beam farthest from the optical axis among the light beams reaching the image height 0.

According to a preferred aspect of the present invention, it is desirable that the following conditional expression (1) is satisfied.
(1) 0.5 <f4 / f3 <2.0
f3: focal length of the third lens group f4: focal length of the fourth lens group

  Conditional expression (1) is a conditional expression for appropriately setting the ratio between the refractive power of the third lens group and the refractive power of the fourth lens group. If the upper limit of conditional expression (1) is exceeded, the refractive power of the third lens group will be too large. For this reason, spherical aberration generated in the third lens group becomes large. On the other hand, if the lower limit of conditional expression (1) is not reached, the refractive power of the third lens group becomes too small. Therefore, the amount of movement of the moving lens group becomes large in order to correct field curvature.

According to a preferred aspect of the present invention, it is desirable that the following conditional expression (2) is satisfied.
(2) 1.2 <f / f1 <3.0
f: Focal length of the entire photographing lens system at infinite focus f1: Focal length of the first lens group

  Conditional expression (2) is a conditional expression for appropriately setting the refractive power of the first lens group. If the upper limit of conditional expression (2) is exceeded, the refractive power of the first lens group will become too large. For this reason, the variation of spherical aberration during close-up shooting cannot be sufficiently corrected, and correction of chromatic aberration in the first lens group becomes difficult. On the other hand, if the lower limit of conditional expression (2) is not reached, the refractive power of the first lens group becomes too small. Therefore, although it is advantageous in terms of aberration correction, the total length of the lens becomes large, and accordingly, it becomes difficult to secure the peripheral light amount.

According to a preferred aspect of the present invention, it is desirable that the following conditional expressions (3) and (4) are satisfied.
(3) -0.2 <f / f12 <0.2
(4) -4.0 <f / f2 <-2.0
f: Focal length of the whole photographing lens system at the time of focusing on an object at infinity f12: Composite focal length of the first lens and the second lens group at the time of focusing on an object at infinity f2: Focal length of the second lens group

  Conditional expression (3) is a conditional expression for appropriately setting the combined refractive power of the first lens group and the second lens group. If the upper limit value of conditional expression (3) is exceeded, the combined refractive power becomes too large. For this reason, the divergence action becomes strong, and the diameter (effective diameter) of the lenses after the third lens group becomes large. On the other hand, if the lower limit of conditional expression (3) is not reached, the combined refractive power will be too small. For this reason, it becomes difficult to ensure the back focus.

  Conditional expression (4) is a conditional expression for appropriately setting the refractive power of the second lens group. If the upper limit of conditional expression (4) is exceeded, the refractive power of the second lens group will become too large. For this reason, the aberration generated in the second lens group becomes too large, and the variation in aberration due to focusing becomes significant. On the other hand, if the lower limit of conditional expression (4) is not reached, the refractive power of the second lens group will be too small. For this reason, the amount of movement of the second lens group for focusing becomes too large, and the entire lens length is enlarged, or it becomes difficult to ensure the photographing magnification.

Hereinafter, a photographic lens according to each embodiment of the present invention will be described in detail with reference to the accompanying drawings. The photographic lens according to each embodiment has an angle of view of about 23 ° and an F-number of about 2.8, and is suitable for a photographic lens such as a photographic camera or a still video camera.
The fourth embodiment is a reference example.
(First embodiment)
FIG. 1 is a diagram showing the lens configuration of the taking lens according to the first embodiment of the present invention. (A), (b), and (c) are an infinite distance shooting state and an intermediate distance shooting state (0.5 ×), respectively. ), Shows a lens cross section in the closest photographing state (1.0x).
As shown in FIG. 1, the photographing lens according to the present embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture stop S. And a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When focusing from an infinitely distant object to a close object, the first lens group G1, the fifth lens group G5, and the aperture stop S are fixed, the second lens group G2 moves to the image side, and the third lens group G3 and the fourth lens group G4 are configured to move to the object side along different paths.

The first lens group G1 has, in order from the object side, a biconvex positive lens L1, a positive meniscus lens L2 having a convex surface facing the object side, a biconcave negative lens L3, and a convex surface facing the object side. It consists of a negative meniscus lens L4, a biconvex positive lens L5, a cemented lens of a biconcave negative lens L6 and a positive meniscus lens L7 having a convex surface facing the object side.
The second lens group G2 includes, in order from the object side, a negative meniscus lens L8 having a convex surface facing the object side, a cemented lens of a biconcave negative lens L9 and a positive meniscus lens L10 having a convex surface facing the object side. Become.

The third lens group G3 is composed of a biconvex positive lens L11.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L12 and a negative meniscus lens L13 having a convex surface directed toward the image plane I.
The fifth lens group G5 is composed of a cemented lens of a positive meniscus lens L14 having a convex surface directed toward the image plane I and a biconcave negative lens L15 in order from the object side.
In the present embodiment, the aperture stop S is disposed between the second lens group G2 and the third lens group G3 as described above, and does not move during focusing from an object at infinity to a short distance object. It is comprised so that a diameter may become small.

  Table 1 below lists values of specifications of the photographing lens according to the first example of the present invention. In Table 1 (overall specifications), f represents a focal length, FNO represents an F number, and 2ω represents an angle of view. In (lens data), the surface of the first column is the order of the lens surfaces from the object side, r of the second column is the radius of curvature of the lens surface, d of the third column is the distance between the lens surfaces, and Nd represents the refractive index with respect to the d-line (λ = 587.6 nm), and νd in the fifth column represents the Abbe number with respect to the d-line (λ = 587.6 nm). Further, ∞ represents a plane, and the refractive index of 1.000 is omitted from the description.

(Focusing data) shows the value of the variable interval and the value of the aperture diameter of the aperture stop S in each of the infinity shooting state, the intermediate distance shooting state, and the closest shooting state. D0 represents the distance from the object surface to the first lens surface (shortest shooting distance).
Here, in general, “mm” is used as a unit of the focal length f, the radius of curvature r, and other lengths listed in all the specification values of the following embodiments. However, since the optical system can obtain the same optical performance even when proportionally enlarged or reduced, the unit is not limited to “mm”.
In addition, also in the specification values of all the following examples, the same symbols as in this example are used.

[Table 1]
(Overall specifications)
f = 104.9
FNO = 2.85
2ω = 23.5

(Lens data)
Surface r d Nd νd
1 680.2799 3.4466 1.804000 46.58
2 -160.9179 0.1500
3 58.7799 4.4015 1.618000 63.38
4 320.9588 1.1881
5 -373.2633 1.2000 1.846660 23.78
6 176.3813 1.5000
7 68.3553 1.4000 1.805180 25.43
8 43.8013 0.7434
9 53.2500 5.1334 1.772500 49.61
10 -227.8754 1.7455
11 -144.0156 1.2000 1.595510 39.23
12 36.4974 4.2856 1.804000 46.58
13 356.1347 d13
14 465.2380 1.2000 1.729160 54.66
15 35.1870 3.0161
16 -253.1432 1.2000 1.772500 49.61
17 29.0405 3.3679 1.846660 23.78
18 129.4966 d18
19 ∞ d19 Aperture stop S
20 149.3341 4.1438 1.497000 81.61
21 -54.1838 d21
22 85.2158 5.6599 1.729160 54.66
23 -49.9973 1.2000 1.846660 23.78
24 -159.2344 d24
25 -60.7762 4.8500 1.805180 25.43
26 -36.1123 1.2000 1.581440 40.75
27 124.2054

(Focusing data)
Infinity shooting state Medium distance shooting state Closest shooting state
d0 ∞ 232.70000 145.00000
d13 1.78400 10.68500 19.84400
d18 20.02700 11.12800 2.00000
d19 22.21600 13.74500 6.96000
d21 9.45600 7.81200 5.19900
d24 4.91900 15.02000 24.42300
Diaphragm diameter 26.54 24.74 21.72

2, 3 and 4 are graphs showing various aberrations of the photographing lens according to the first example of the present invention in the infinity photographing state, the intermediate distance photographing state (0.5 times), and the closest photographing state (1.0 times).
In each aberration diagram, FNO is the F number, NA is the numerical aperture, A is the half field angle (unit is degrees), and H0 is the object height. In the spherical aberration diagram, the F-number value or the maximum value of the numerical aperture corresponding to the maximum aperture is shown, and in the astigmatism diagram and the distortion diagram, the maximum value of the half field angle or the maximum value of the object height is shown. In each aberration diagram, d represents an aberration curve of the d line (λ = 587.6 nm), and g represents an aberration curve of the g line (λ = 435.8 nm). Further, in the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane.
In addition, in the various aberration diagrams of each example described below, the same reference numerals as those in this example are used.

  From the various aberration diagrams, the photographic lens according to the present embodiment has excellent image performance with excellent correction of various aberrations in a wide range of imaging magnifications from an object at infinity to a close object near the same magnification. I understand.

(Second embodiment)
FIG. 5 is a diagram showing the lens configuration of the taking lens according to the second embodiment of the present invention. FIGS. 5A, 5B, and 5C are an infinite photographing state and an intermediate photographing state (0.5 times), respectively. ), Shows a lens cross section in the closest photographing state (1.0x).
As shown in FIG. 5, the photographing lens according to the present embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture stop S. And a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When focusing from an infinitely distant object to a close object, the first lens group G1, the fifth lens group G5, and the aperture stop S are fixed, the second lens group G2 moves to the image side, and the third lens group G3 and the fourth lens group G4 are configured to move to the object side along different paths.

The first lens group G1 has, in order from the object side, a biconvex positive lens L1, a positive meniscus lens L2 having a convex surface facing the object side, a biconcave negative lens L3, and a convex surface facing the object side. It consists of a negative meniscus lens L4, a biconvex positive lens L5, a cemented lens of a biconcave negative lens L6 and a positive meniscus lens L7 having a convex surface facing the object side.
The second lens group G2 includes, in order from the object side, a negative meniscus lens L8 having a convex surface facing the object side, a cemented lens of a biconcave negative lens L9 and a positive meniscus lens L10 having a convex surface facing the object side. Become.

The third lens group G3 is composed of a cemented lens of a negative meniscus lens L11 having a convex surface directed toward the object side and a biconvex positive lens L12 in order from the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L13 and a negative meniscus lens L14 having a convex surface directed toward the image plane I.
The fifth lens group G5 is composed of, in order from the object side, a cemented lens of a positive meniscus lens L15 having a convex surface directed toward the image plane I and a biconcave negative lens L16.
In the present embodiment, the aperture stop S is disposed between the second lens group G2 and the third lens group G3 as described above, and does not move during focusing from an object at infinity to a short distance object. It is comprised so that a diameter may become small.
Table 2 below lists values of specifications of the photographing lens according to the second example of the present invention.

[Table 2]
(Overall specifications)
f = 105.0
FNO = 2.85
2ω = 23.5

(Lens data)
Surface r d Nd νd
1 412.6945 3.7272 1.804000 46.58
2 -165.3299 0.1500
3 57.3867 4.3604 1.618000 63.38
4 255.7404 1.1612
5 -578.1405 1.2000 1.846660 23.78
6 143.9390 1.5000
7 67.4025 1.4000 1.805180 25.43
8 44.1550 0.7168
9 53.4698 5.1055 1.772500 49.61
10 -234.8579 1.8021
11 -136.8714 1.2000 1.595510 39.23
12 36.1437 4.2684 1.804000 46.58
13 442.1546 d13
14 884.2854 1.2000 1.729160 54.66
15 34.6345 3.1003
16 -189.5282 1.2000 1.772500 49.61
17 29.6854 3.3840 1.846660 23.78
18 149.2155 d18
19 ∞ d19 Aperture stop S
20 210.5758 1.2000 1.666800 33.04
21 111.9672 4.4058 1.497000 81.61
22 -52.8057 d22
23 81.0402 5.6434 1.729160 54.66
24 -52.8987 1.2000 1.846660 23.78
25 -146.8823 d25
26 -63.9041 3.1891 1.805180 25.43
27 -36.1860 1.2000 1.581440 40.75
28 136.5297

(Focusing data)
Infinity shooting state Medium distance shooting state Closest shooting state
d0 ∞ 225.90000 145.00000
d13 1.72400 10.42700 19.55700
d18 19.82800 11.11000 2.00000
d19 18.68200 13.86200 6.08200
d22 12.24000 5.37100 4.71200
d25 5.85700 17.56600 25.97600
Diaphragm diameter 26.60 24.74 21.28

FIGS. 6, 7 and 8 are graphs showing various aberrations of the photographing lens according to the second example of the present invention in the infinity photographing state, the intermediate distance photographing state (0.5 times), and the closest photographing state (1.0 times).
From the various aberration diagrams, the photographic lens according to the present embodiment has excellent image performance with excellent correction of various aberrations in a wide range of imaging magnifications from an object at infinity to a close object near the same magnification. I understand.

(Third embodiment)
FIG. 9 is a diagram showing the lens configuration of the photographing lens according to the third example of the present invention. (A), (b), and (c) are an infinite photographing state and an intermediate distance photographing state (0.5 times), respectively. ), Shows a lens cross section in the closest photographing state (1.0x).
As shown in FIG. 9, the photographing lens according to the present example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture stop S. And a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When focusing from an infinitely distant object to a close object, the first lens group G1, the fifth lens group G5, and the aperture stop S are fixed, the second lens group G2 moves to the image side, and the third lens group G3 and the fourth lens group G4 are configured to move to the object side along different paths.

The first lens group G1 has, in order from the object side, a biconvex positive lens L1, a positive meniscus lens L2 having a convex surface facing the object side, a biconcave negative lens L3, and a convex surface facing the object side. It consists of a negative meniscus lens L4, a biconvex positive lens L5, a cemented lens of a biconcave negative lens L6 and a positive meniscus lens L7 having a convex surface facing the object side.
The second lens group G2 includes, in order from the object side, a negative meniscus lens L8 having a concave surface facing the image plane I side, a negative lens L9 having a biconcave shape, and a positive meniscus lens L10 having a convex surface facing the object side. It consists of.

The third lens group G3 is composed of a cemented lens of a negative meniscus lens L11 having a convex surface directed toward the object side and a biconvex positive lens L12 in order from the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L13 and a negative meniscus lens L14 having a convex surface directed toward the image plane I.
The fifth lens group G5 includes, in order from the object side, a cemented lens of a biconcave negative lens L15 and a positive meniscus lens L16 having a convex surface directed toward the object side.
In the present embodiment, the aperture stop S is disposed between the second lens group G2 and the third lens group G3 as described above, and does not move during focusing from an object at infinity to a short distance object. It is comprised so that a diameter may become small.
Table 3 below lists values of specifications of the photographing lens according to the third example of the present invention.

[Table 3]
(Overall specifications)
f = 104.9
FNO = 2.85
2ω = 23.5

(Lens data)
Surface r d Nd νd
1 263.9134 4.2693 1.804000 46.58
2 -173.7122 0.1500
3 63.8036 3.6936 1.569070 71.31
4 188.4748 1.7043
5 -303.9443 1.2000 1.846660 23.78
6 232.4753 1.5000
7 72.9142 1.4000 1.805180 25.43
8 43.2139 0.6369
9 50.7224 5.4616 1.772500 49.61
10 -201.2030 1.7771
11 -125.1228 1.2000 1.595510 39.23
12 35.2662 4.7571 1.804000 46.58
13 1284.4263 d13
14 18069.9670 1.2000 1.729160 54.66
15 36.1440 2.9166
16 -275.1713 1.2000 1.772500 49.61
17 29.7576 3.4059 1.846660 23.78
18 136.6108 d18
19 ∞ d19 Aperture stop S
20 166.0807 1.2000 1.666800 33.04
21 95.5992 4.5411 1.497000 81.61
22 -55.0690 d22
23 100.9064 5.5000 1.729160 54.66
24 -58.7973 1.2000 1.846660 23.78
25 -142.6600 d25
26 -83.6028 1.5000 1.617720 49.82
27 33.8301 4.3343 1.735199 41.08
28 105.8964

(Focusing data)
Infinity shooting state Medium distance shooting state Closest shooting state
d0 ∞ 232.00000 145.00000
d13 1.60000 10.68900 20.06700
d18 20.39200 11.30000 2.00000
d19 19.92700 13.22700 6.56600
d22 10.50700 6.05200 3.76600
d25 8.45100 19.61400 28.44800
Diaphragm diameter 26.64 24.46 21.18

FIGS. 10, 11 and 12 are graphs showing various aberrations of the photographing lens according to the third example of the present invention in the infinite distance photographing state, the intermediate distance photographing state (0.5 times), and the closest photographing state (1.0 times).
From the various aberration diagrams, the photographic lens according to the present embodiment has excellent image performance with excellent correction of various aberrations in a wide range of imaging magnifications from an object at infinity to a close object near the same magnification. I understand.

(Fourth embodiment)
FIG. 13 is a diagram showing the lens configuration of the photographing lens according to the fourth example of the present invention. (A), (b), and (c) are an infinite distance photographing state and an intermediate distance photographing state (0.5 times), respectively. ), Shows a lens cross section in the closest photographing state (1.0x).
As shown in FIG. 13, the photographing lens according to the present example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and an aperture stop S. And a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When focusing from an infinitely distant object to a close object, the first lens group G1, the fifth lens group G5, and the aperture stop S are fixed, the second lens group G2 moves to the image side, and the third lens group G3 and the fourth lens group G4 are configured to move to the object side along different paths.

The first lens group G1 includes, in order from the object side, a biconvex positive lens L1, a positive meniscus lens L2 having a convex surface facing the object side, a negative meniscus lens L3 having a convex surface facing the object side, and an object side. And a positive meniscus lens L4 having a convex surface.
The second lens group G2 has, in order from the object side, a cemented lens of a negative meniscus lens L5 having a convex surface facing the object side and a positive meniscus lens L6 having a convex surface facing the object side, and a convex surface facing the image surface I side. And a negative meniscus lens L7.

The third lens group G3 is composed of a biconvex positive lens L8.
The fourth lens group G4 is composed of, in order from the object side, a cemented lens of a biconvex positive lens L9 and a negative meniscus lens L10 having a convex surface directed toward the image plane I.
The fifth lens group G5 includes, in order from the object side, a cemented lens of a biconcave negative lens L11 and a positive meniscus lens L12 having a convex surface directed toward the object side.
In the present embodiment, the aperture stop S is disposed between the second lens group G2 and the third lens group G3 as described above, and does not move during focusing from an object at infinity to a short distance object. It is comprised so that a diameter may become small.
Table 4 below provides values of specifications of the photographing lens according to the fourth example of the present invention.

[Table 4]
(Overall specifications)
f = 106.0
FNO = 2.88
2ω = 22.8

(Lens data)
Surface r d Nd νd
1 87.2332 5.5637 1.589130 61.18
2 -1140.2393 0.2000
3 46.1848 5.1624 1.497000 81.61
4 107.5736 0.2000
5 50.2483 2.0000 1.805180 25.43
6 27.2957 6.2778
7 31.0138 5.8317 1.584532 62.89
8 343.2530 d8
9 134.4788 1.5000 1.696800 55.52
10 19.3324 3.8736 1.805180 25.43
11 28.7089 4.5005
12 -51.1822 1.5000 1.729160 54.66
13 -129.7646 d13
14 ∞ d14 Aperture stop S
15 23093.7170 3.0123 1.618000 63.38
16 -78.1130 d16
17 791.4537 5.1412 1.708232 54.37
18 -31.0723 1.0000 1.805180 25.43
19 -57.8228 d19
20 -47.4936 1.5000 1.531720 48.87
21 46.8575 3.9041 1.834000 37.17
22 275.7271

(Focusing data)
Infinity shooting state Medium distance shooting state Closest shooting state
d0 ∞ 257.70000 155.90000
d8 1.60000 9.09480 19.43260
d13 19.18830 11.41530 1.00000
d14 20.98260 4.75220 1.00000
d16 7.77900 8.91330 1.00000
d19 16.55460 31.91860 43.67170
Diaphragm diameter 25.30 23.96 20.30

Table 5 below lists the values corresponding to the conditional expressions of the photographic lenses according to the respective examples.
[Table 5]
(Values for conditional expressions)
First Example Second Example Third Example Fourth Example (1) f4 / f3 + 1.09 + 0.89 + 1.01 + 0.68
(2) f / f1 +1.88 +1.93 +1.92 +1.82
(3) f / f12 -0.075 -0.103 -0.069 +0.001
(4) f / f2 -2.82 -2.96 -2.86 -2.69

FIGS. 14, 15 and 16 are graphs showing various aberrations of the photographing lens according to the fourth example of the present invention in the infinite distance photographing state, the intermediate distance photographing state (0.5 times), and the closest photographing state (1.0 times).
From the various aberration diagrams, the photographic lens according to the present embodiment has excellent image performance with excellent correction of various aberrations in a wide range of imaging magnifications from an object at infinity to a close object near the same magnification. I understand.

  According to each of the above embodiments, a photographic lens having a good image performance over the entire focusing area can be quickly obtained by moving a lightweight lens group from an infinitely distant object to a close object near the same magnification. can do.

FIG. 2 is a diagram illustrating a lens configuration of a photographic lens according to Example 1 of the present invention, in which (a), (b), and (c) are the infinity shooting state, the intermediate distance shooting state (0.5 times), and the closest The lens cross section in the shooting state (1.0x) is shown. FIG. 6 is a diagram illustrating all aberrations of the photographing lens according to the first example of the present invention when the photographing lens is photographed at infinity. FIG. 6 is a diagram illustrating various aberrations of the photographing lens according to the first example of the present invention in an intermediate distance photographing state (0.5 times). FIG. 6 is a diagram illustrating all aberrations of the photographing lens according to Example 1 of the present invention in the closest photographing state (1.0 ×). It is a figure which shows the lens structure of the imaging lens which concerns on 2nd Example of this invention, (a), (b), (c) is respectively an infinite distance imaging | photography state, an intermediate distance imaging | photography state (0.5 time), and the nearest. The lens cross section in the shooting state (1.0x) is shown. FIG. 9 is a diagram illustrating all aberrations of the photographing lens according to the second example of the present invention when the photographing lens is photographed at infinity. FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to the second example of the present invention in an intermediate distance photographing state (0.5 times). FIG. 6 is a diagram illustrating various aberrations of the photographing lens according to Example 2 of the present invention in the closest photographing state (1.0 ×). It is a figure which shows the lens structure of the imaging lens which concerns on 3rd Example of this invention, (a), (b), (c) is respectively an infinite distance imaging | photography state, an intermediate distance imaging | photography state (0.5 time), and the nearest. The lens cross section in the shooting state (1.0x) is shown. FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to the third example of the present invention in the state of photographing at infinity. FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to the third example of the present invention in an intermediate distance photographing state (0.5 times). FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to Example 3 of the present invention in the closest photographing state (1.0 ×). It is a figure which shows the lens structure of the photographic lens which concerns on 4th Example of this invention, (a), (b), (c) is respectively the infinity photography state, the intermediate distance photography state (0.5 time), and the nearest. The lens cross section in the shooting state (1.0x) is shown. FIG. 12 is a diagram illustrating all aberrations of the photographing lens according to the fourth example of the present invention in the state of photographing at infinity. FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to the fourth example of the present invention in an intermediate distance photographing state (0.5 times). FIG. 12 is a diagram illustrating various aberrations of the photographing lens according to Example 4 of the present invention in the closest photographing state (1.0 ×).

Explanation of symbols

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group S Aperture stop I Image surface

Claims (5)

In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power A group and a fifth lens group having negative refractive power ,
During focusing from an infinite object to a close object, the first lens group is fixed, the second lens group moves to the image side, the third lens group moves to the object side, and the fourth lens group moves toward the object side in a different trajectory and the third lens group, the fifth lens group Ri fixed der,
A photographic lens characterized by satisfying the following conditional expression:
0.89 ≦ f4 / f3 <2.0
f3: focal length of the third lens group
f4: focal length of the fourth lens group An aperture stop is provided between the second lens group and the third lens group;
The photographing lens according to claim 1, wherein the aperture stop is fixed when focusing from an object at infinity to an object at a short distance.   The photographing lens according to claim 2, wherein the aperture diameter of the aperture stop is reduced when focusing from an object at infinity to an object at a short distance. The photographic lens according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
1.2 <f / f1 <3.0
f: Focal length of the entire photographing lens system when focusing on an object at infinity
f1: Focal length of the first lens group The photographic lens according to claim 1, wherein the following conditional expression is satisfied.
−0.2 <f / f12 <0.2
−4.0 <f / f2 <−2.0
f: Focal length of the entire photographing lens system when focusing on an object at infinity
f12: the combined focal length of the first lens and the second lens group when focusing on an object at infinity
f2: focal length of the second lens group

Images