JP5151524B2 - PHOTOGRAPHIC LENS, OPTICAL DEVICE EQUIPPED WITH THIS PHOTOGRAPHIC LENS, AND IMAGE-FORMING METHOD - Google Patents

Description

  The present invention relates to a photographic lens, an optical apparatus including the photographic lens, and an imaging method.

Conventionally, there is a so-called Gaussian lens as a lens type in which a F-number is relatively bright and high optical performance can be easily obtained in a photographic camera, a video camera, etc., and is still widely used (for example, Patent Document 1). reference).
JP-A-1-30211

  However, the conventional lens has a problem that the correction of chromatic aberration, particularly the secondary spectrum, is insufficient.

  The present invention has been made in view of such a problem, and has an F number of about 1.2, can satisfactorily correct various aberrations, particularly chromatic aberration, and has high optical performance over the entire screen. An object of the present invention is to provide a photographing lens.

In order to solve the above-described problem, a photographic lens according to a first aspect of the present invention includes a first lens component having a positive refractive power on the most object side, and a second lens component having a positive refractive power in order from the object side. And a cemented lens in which a positive lens and a negative lens are bonded in this order from the object side. The refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, the refractive index of the second lens component with respect to the d-line is n2, and the Abbe number is ν2 . When the refractive index of the positive lens with respect to the d-line is n8, the Abbe number is ν8, the refractive index with respect to the d-line of the negative lens of the cemented lens arranged closest to the image side is n9, and the Abbe number is ν9, ) / 2> 1.49
(Ν1 + ν2) / 2> 60
n8> n9
ν8> ν9
It is configured to satisfy the following conditions.

The photographic lens according to the second aspect of the present invention has, on the most object side, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side, A front negative lens component having a negative refractive power in order from the object side between the second lens component and the cemented lens, having a cemented lens on the image side, in which a positive lens and a negative lens are bonded in order from the object side And an aperture stop, a rear negative lens component having a negative refractive power, and a rear positive lens component having a positive refractive power, wherein the refractive index of the first lens component with respect to the d-line is n1, and the Abbe number Is ν1, the refractive index of the second lens component with respect to the d-line is n2, the Abbe number is ν2, the radius of curvature of the image side surface of the front negative lens component is r8, and the focal length of the entire taking lens system is f. When
(N1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
0.3 <r8 / f <0.5
It is configured to satisfy the following conditions.

The photographic lens according to the third aspect of the present invention has, on the most object side, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side, A front negative lens component having a negative refractive power in order from the object side between the second lens component and the cemented lens, having a cemented lens on the image side, in which a positive lens and a negative lens are bonded in order from the object side An aperture stop, a rear negative lens component having a negative refractive power, and a rear positive lens component having a positive refractive power, and an object between the second lens component and the front negative lens component A third meniscus lens component having a convex surface facing the side, the front negative lens component is a fourth lens component having a meniscus shape having a convex surface facing the object side, and the rear negative lens component is a biconcave second lens component. 5 lens components, the refractive index of the first lens component with respect to d-line n1, the Abbe number and .nu.1, when the refractive index at the d-line of the second lens component n2, the Abbe number was .nu.2, the following equation
(N1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
It is configured to satisfy the following conditions.

The photographic lens according to the fourth aspect of the present invention has, on the most object side, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side, On the image side, there is a cemented lens in which a positive lens and a negative lens are bonded in order from the object side, the refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, and the second lens component with respect to the d-line When the refractive index is n2 and the Abbe number is ν2,
(N1 + n2) /2≧1.592
(Ν1 + ν2) /2≧68.36
It is configured to satisfy the following conditions.
The photographic lens according to the fifth aspect of the present invention has, on the most object side, a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side, On the image side, there is a cemented lens in which a positive lens and a negative lens are bonded in order from the object side, the refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, and the second lens component with respect to the d-line When the refractive index is n2 and the Abbe number is ν2,
(N1 + n2) /2≧1.5447
(Ν1 + ν2) /2≧74.95
It is configured to satisfy the following conditions.

In such a photographic lens, the refractive index of the positive lens of the cemented lens disposed closest to the image side with respect to the d-line is n8, the Abbe number is ν8, and the negative lens d of the cemented lens disposed closest to the image side. When the refractive index with respect to the line is n9 and the Abbe number is ν9, the following expression n8> n9
ν8> ν9
It is preferable to satisfy the following conditions.

Also, in such a photographing lens, when the radius of curvature of the image side surface of the front negative lens component is r8 and the focal length of the whole photographing lens system is f, the following expression 0.3 <r8 / f <0. 5
It is preferable to satisfy the following conditions.

  In addition, such a photographing lens includes a front negative lens component having negative refractive power, an aperture stop, and a rear side having negative refractive power in order from the object side between the second lens component and the cemented lens. It is preferable to have a negative lens component and a rear positive lens component having a positive refractive power.

  In addition, such a photographing lens preferably has a meniscus third lens component having a convex surface facing the object side between the second lens component and the front negative lens component.

  In such a photographing lens, it is preferable that a seventh lens component having a positive refractive power is provided between the sixth lens component as the rear positive lens component and the cemented lens.

  In such a photographing lens, it is preferable that the rear negative lens component and the rear positive lens component are a cemented cemented lens.

  In such a photographing lens, it is preferable that the first lens component and the second lens component each have a meniscus shape with a convex surface facing the object side.

  In addition, it is preferable that such a photographing lens is configured such that the cemented lens disposed on the most image side and the other lens move along the optical axis at different speeds during focusing.

Further, in such a photographing lens, when the focal length of the cemented lens arranged closest to the image side is f89 and the focal length of the entire photographing lens system is f, the following expression 1 <f89 / f <2
It is preferable to satisfy the following conditions.

  In such a photographing lens, it is preferable that the positive lens component of the cemented lens arranged closest to the image side is a biconvex shape.

  An optical apparatus according to the present invention includes any one of the above-described photographing lenses.

The imaging method according to the present invention has a first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side, and the most image side. And a refractive index with respect to the d-line of the second lens component, where n1 is the refractive index of the first lens component with respect to the d-line, and ν1 is the Abbe number. Is n2, Abbe number is ν2, the refractive index for the d-line of the positive lens of the cemented lens arranged closest to the image side is n8, the Abbe number is ν8, and d of the negative lens of the cemented lens arranged closest to the image side When the refractive index for a line is n9 and the Abbe number is ν9,
(N1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
n8> n9
ν8> ν9
This is performed using a photographic lens that satisfies the above conditions .

  When the photographing lens according to the present invention, the optical apparatus equipped with the photographing lens, and the zooming method are configured as described above, the F number is about 1.2, and various aberrations, particularly chromatic aberration, of the entire screen are improved. It is possible to correct the photographic lens with high optical performance over the entire screen.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the photographing lens ZL includes, in order from the object side along the optical axis, a first lens component G1 having a positive refractive power, a second lens component G2 having a positive refractive power, It has a cemented lens G89 in which a positive lens G8 and a negative lens G9 are bonded together in order from the object side on the most image side. With this configuration, the photographing lens ZL can be a large-diameter lens having an effective diameter of about 25 to 30 mm. Further, by disposing the cemented lens G89 in which the positive lens G8 and the negative lens G9 are bonded to the most image side lens, the image side lens also has an achromatic effect, and chromatic aberration can be corrected as a whole. By using such a cemented lens, total reflection of light rays can be prevented, and light rays can be passed through the lens satisfactorily.

  As a specific embodiment of the photographing lens ZL, as shown in FIG. 1, in addition to the first lens component G1, the second lens component G2, and the cemented lens G89, the second lens component G2 Between the image side and the object side of the cemented lens G89, in order from the object side, a third meniscus lens component G3 having a convex surface facing the object side, a front negative lens component G4 having negative refractive power, and an aperture A cemented lens G56 in which a stop S, a rear negative lens component G5 having negative refractive power and a rear positive lens component G6 having positive refractive power are bonded together, and a seventh lens component G7 having positive refractive power As a whole, it is desirable that the lens is composed of 9 lenses in 7 groups.

  The photographing lens ZL is a modification of a so-called Gauss type lens. In the Gaussian type, the lens has a substantially symmetrical shape before and after the stop, so that correction of distortion and the like is easy due to the symmetry. Further, in the present photographing lens ZL, three lens components are arranged on the object side of the negative meniscus lens on the object side from the aperture stop S (the front negative lens component G4 in FIG. 1), as in JP-A-1-30211. (In FIG. 1, the first to third lens components G1 to G3), the respective radii of curvature are increased, and the occurrence of spherical aberration is reduced.

  In the photographic lens ZL, the first lens component G1 and the second lens component G2 each preferably have a meniscus shape with a convex surface facing the object side. The front negative lens component G4, which is the fourth lens component, preferably has a meniscus shape with a convex surface facing the object side. The rear negative lens component G5, which is the fifth lens component, preferably has a biconcave shape. Furthermore, the positive lens G8 of the cemented lens G89 disposed on the most image side preferably has a biconvex shape.

  As described above, when the third lens component G3 having positive or negative refractive power is disposed between the second lens component G2 and the front negative lens component G4, the third lens component G3 is 1 A two-sheet configuration is preferred. When the seventh lens component G7 is disposed between the rear negative lens component G5 and the cemented lens G89, the seventh lens component G7 preferably has one or two lenses and has a positive refractive power. Is preferred.

  The conditions for configuring such a photographic lens ZL will now be described. First, the photographic lens ZL has a refractive index of the first lens component G1 with respect to the d-line as n1, an Abbe number as ν1, a refractive index with respect to the d-line of the second lens component G2 as n2, and an Abbe number as ν2. It is configured to satisfy the following conditional expressions (1) and (2).

(N1 + n2) / 2> 1.49 (1)
(Ν1 + ν2) / 2> 60 (2)

  Conditional expression (1) and conditional expression (2) are conditions defining the refractive power and dispersion of the two meniscus lens components G1 and G2 on the object side. By satisfying conditional expression (1) and conditional expression (2) at the same time, the dispersion is smaller with respect to the refractive index than a general material, and chromatic aberration can be corrected well. In particular, the lower coma can be corrected well. In the deformed Gaussian main photographing lens ZL, in which the lens component on the object side has a great influence on the occurrence of chromatic aberration, satisfying conditional expressions (1) and (2) is particularly effective for correcting chromatic aberration. Can be demonstrated.

  Further, in the photographing lens ZL, the negative lens of the cemented lens G89 disposed closest to the image side, where the refractive index of the cemented lens G89 disposed closest to the image side with respect to the d-line of the positive lens G8 is n8 and the Abbe number is ν8. It is desirable to satisfy the following conditional expression (3) and conditional expression (4), where n9 is the refractive index of the G9 for the d-line and ν9 is the Abbe number.

n8> n9 (3)
ν8> ν9 (4)

  Conditional expression (3) and conditional expression (4) are conditions that prescribe the refractive power and dispersion of the positive lens G8 and the negative lens G9 of the cemented lens G89 disposed on the most image side. By satisfying conditional expression (3), an increase in Petzval sum can be prevented. Further, chromatic aberration can be corrected by satisfying conditional expression (4). Here, when a material having a high refractive index is used for the positive lens G8 in order to suppress the occurrence of coma and spherical aberration, the dispersion increases, and the negative lens G9 tends to have a high refractive index for correcting chromatic aberration. . This increases the Petzval sum. Therefore, the cemented lens G89 arranged on the most image side is a cemented lens that satisfies the conditional expressions (3) and (4) at the same time, so that achromatic and Petzval can be obtained even when a material with a high refractive index is used. The sum can be prevented from increasing. In order to further secure the effect of the present embodiment, in conditional expression (4), the Abbe number ν8 of the positive lens G8 is 20 or more larger than the Abbe number ν9 of the negative lens G9. It is preferable to satisfy (a).

ν8-ν9> 20 (a)

  The photographic lens ZL further has a radius of curvature r8 of the image side surface (in FIG. 1, the eighth lens surface counted from the object side) of the front negative lens component G4, and the focal length of the entire photographic lens ZL system. It is desirable to satisfy the following conditional expression (5) where f is:

0.3 <r8 / f <0.5 (5)

  Conditional expression (5) is a condition that defines the ratio of the radius of curvature of the image-side surface of the front negative lens component G4 to the focal length f. If the lower limit of conditional expression (5) is not reached, it will be difficult to correct coma. Further, the entire power of the rear group becomes strong, and the spherical aberration cannot be corrected well as a whole, which is not preferable. On the contrary, if the upper limit value of conditional expression (5) is exceeded, the Petzval sum becomes large, and it becomes difficult to correct the curvature of field, which is not preferable.

  Further, the photographing lens ZL may be a focusing lens group that performs focusing from an object at infinity to a near object by moving a single lens component or a plurality of lens components, or a part of the lens components, in the optical axis direction. . In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In this embodiment, it is desirable that the cemented lens G89 disposed on the most image side of the photographing lens ZL and the other lenses are configured to move along the optical axis at different speeds during focusing. It is possible to prevent spherical aberration and image surface tilt when focusing on a short-distance object. The aperture stop S moves along the optical axis together with the front negative lens component G4 or the rear negative lens component G5 during focusing.

  The cemented lens G89 arranged closest to the image side further satisfies the following conditional expression (6), where f89 is the focal length of the cemented lens G89 and f is the focal length of the entire photographing lens system. Is desirable.

1 <f89 / f <2 (6)

  Conditional expression (6) is a condition that defines the ratio between the focal length of the cemented lens G89 arranged on the most image side and the focal length of the entire taking lens ZL system. If the upper limit of conditional expression (6) is exceeded, the entire photographic lens will be enlarged. Further, when focusing at a finite distance, the fluctuation of the image surface becomes large, and it becomes difficult to correct aberrations from infinity to a short distance. Moreover, it is not preferable because the moving distance is large and the function is severely deteriorated. On the other hand, if the lower limit of conditional expression (6) is not reached, it will be difficult to correct aberrations, particularly spherical aberrations, which is not preferable.

  The photographic lens ZL according to the present example has a focal length in terms of 35 mm film size of about 60 to 150 mm, preferably about 80 to 90 mm. In addition, the photographing lens ZL according to the present embodiment is more preferably about 10 to 30 mm in a state where the distance (back focus) from the image side surface of the positive lens G9 arranged closest to the image side to the image surface is the smallest. desirable.

  The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  First, the lens surface may be an aspherical surface. At this time, any one of an aspheric surface by grinding, a glass mold aspheric surface in which glass is formed into an aspheric shape by a mold, and a composite aspheric surface in which resin is formed in an aspheric shape on the surface of the glass may be used. The image side surface of the front negative lens component G4 (negative meniscus lens L4 in FIG. 1), the object side surface of the rear negative lens component G5 (biconcave lens L5 in FIG. 1), and the rear positive lens component G6 (FIG. 1, at least one of the image side surface of the biconvex lens L6) and one of the object side surface of the positive lens G8 (biconvex lens L8 in FIG. 1) is preferably an aspherical surface. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably disposed between the front negative lens component G4 (negative meniscus lens L4 in FIG. 1) and the rear negative lens component G5 (biconcave lens L5 in FIG. 1). The role may be substituted by a lens frame without providing a member as an aperture stop.

  Furthermore, an antireflection film having a high transmittance in a wide wavelength range is applied to each lens surface, thereby reducing flare and ghost and achieving high contrast and high optical performance.

  9 and 10 show a configuration of an electronic still camera 1 (hereinafter simply referred to as camera 1) as an optical apparatus including the above-described photographing lens ZL. In this camera 1, when a power button (not shown) is pressed, a shutter (not shown) of the photographic lens ZL is opened, and light from a subject (not shown) is condensed by the photographic lens ZL, and an image pickup device arranged on the image plane I. The image is formed on C (for example, film, CCD, CMOS, etc.). The subject image formed on the image sensor C is displayed on the liquid crystal monitor 2 disposed behind the camera 1. The photographer determines the composition of the subject image while looking at the liquid crystal monitor 2, and then presses the release button 3 to photograph the subject image with the image sensor C and records and saves it in a memory (not shown).

  The camera 1 includes an auxiliary light emitting unit 4 that emits auxiliary light when the subject is dark, and a wide (W) when zooming the zoom optical system ZL from the wide-angle end state (W) to the telephoto end state (T). A tele (T) button 5 and function buttons 6 used for setting various conditions of the camera 1 are arranged.

  In addition, in order to explain the present invention in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this.

  Embodiments of the present invention will be described below with reference to the drawings. 1, 3, 5, and 7 are cross-sectional views illustrating the configurations of the photographing lenses ZL (ZL1 to ZL4) according to the respective embodiments. From the infinity in focusing of the photographing lenses ZL1 to ZL4, FIG. The direction in which the lens group is moved along the optical axis when focusing on a short-distance object is indicated by an arrow. As shown in FIGS. 1 to 3, the photographing lenses ZL1 to ZL4 according to the present embodiment are all first lenses having positive refractive power in order from the object side along the optical axis as described above. A component G1, a second lens component G2 having a positive refractive power, a meniscus third lens component G3 having a convex surface facing the object side, and a front negative lens component having a negative refractive power (fourth lens component) G4, an aperture stop S, and a rear negative lens component having negative refractive power (fifth lens component) G5 and a rear positive lens component having positive refractive power (sixth lens component) G6 bonded together The lens G56 includes a seventh lens component G7 having a positive refractive power, a cemented lens G89 in which a positive lens G8 and a negative lens G9 are bonded, and a filter group FL. Here, the filter group FL includes a low-pass filter, an infrared cut filter, and the like. As shown in FIG. 10, the image plane I is imaged on an image sensor C (for example, film, CCD, CMOS, etc.).

[First embodiment]
FIG. 1 is a diagram showing the configuration of the taking lens ZL1 according to the first embodiment of the present invention. In the photographic lens ZL1 of FIG. 1, the first lens component G1 includes a positive meniscus lens L1 having a convex surface facing the object side, and the second lens component G2 includes a positive meniscus lens L2 having a convex surface facing the object side. The third lens component G3 is composed of a positive meniscus lens L3 having a convex surface facing the object side, and the front negative lens component (fourth lens component) G4 is composed of a negative meniscus lens L4 having a convex surface facing the object side. The cemented lens G56 is configured by bonding a rear negative lens component G5 (fifth lens component) composed of a biconcave lens L5 and a rear positive lens component G6 (sixth lens component) composed of a biconvex lens L6. The seventh lens component G7 is composed of a biconvex positive lens L7, and the cemented lens G89 is composed of an eighth lens G8 composed of a biconvex lens L8 and a biconcave lens L9. Constructed by bonding the ninth lens G9.

  Focusing from a long distance to a short distance is performed by dividing the entire photographing lens ZL into two groups of lens components G1 to G7 and a cemented lens G89, and separately feeding them to the object side. At this time, the aperture stop S moves along the optical axis together with the front negative lens component G4 and the rear negative lens component G5 during focusing. The moving speed at the time of focusing is such that the front lens group (G1 to G7) moves faster than the rear lens group (junction lens G89).

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents the focal length, FNO represents the F number, and 2ω represents the angle of view. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the refractive index and Abbe number are each The value for the d-line (λ = 587.6 nm) is shown. The total lens length represents the distance on the optical axis from the first surface of the lens surface to the image plane when focusing on infinity. Here, “mm” is generally used for the focal length f, the radius of curvature, the surface interval, and other length units listed in all the following specifications, but the optical system is proportionally enlarged or reduced. However, since the same optical performance can be obtained, it is not limited to this. The radius of curvature of 0.0000 indicates a plane, and the refractive index of air of 1.0000 is omitted. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
f = 32.0
F.NO = 1.2
2ω = 29.9
Image height = 8.5
Total length = 54.6

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 28.9228 4.30 1.5924 68.36
2 228.3618 0.10
3 26.0101 3.39 1.5924 68.36
4 63.1641 0.10
5 19.3125 4.33 1.8160 46.62
6 20.7366 1.70
7 60.3267 1.30 1.6727 32.10
8 10.9478 4.14
9 0.0000 4.55 (Aperture stop)
10 -12.1627 1.00 1.6727 32.10
11 69.4239 5.19 1.8830 40.76
12 -20.9084 0.10
13 270.4986 2.85 1.7550 52.32
14 -37.4965 (d1)
15 46.6626 4.50 1.8830 40.76
16 -25.9360 2.99 1.7618 26.52
17 258.6980 (d2)
18 0.0000 1.00 1.5168 64.10
19 0.0000 1.50
20 0.0000 1.87 1.5168 64.10
21 0.0000 0.40
22 0.0000 0.70 1.5168 64.10
23 0.0000 0.50

  In the first embodiment, the axial air distance d1 between the seventh lens component G7 and the eighth lens G8 (junction lens G89) and the axial air distance d2 between the ninth lens component G9 and the filter group FL are as follows: It changes during focusing. Table 2 below shows the variable intervals at infinity and at a magnification of 1 / 13.6.

(Table 2)
Magnification at infinity 1 / 13.6
d1 0.10 2.05
d2 7.98 9.55

  Table 3 below shows values corresponding to the conditional expressions in the first embodiment. In Table 3, n1 represents the refractive index of the first lens component G1 with respect to the d-line, ν1 represents the Abbe number of the first lens component G1, n2 represents the refractive index of the second lens component G2 with respect to the d-line, and ν2 Is the Abbe number of the second lens component G2, n8 is the refractive index of the positive lens G8 with respect to the d-line, ν8 is the Abbe number of this positive lens G8, n9 is the refractive index of the negative lens G9 with respect to the d-line, and ν9. Represents the Abbe number of the negative lens G9, r8 represents the radius of curvature of the image-side eighth surface of the front negative lens component G4, and f represents the focal length of the entire taking lens ZL system. The description of the above symbols is the same in the following embodiments.

(Table 3)
(1) (n1 + n2) / 2 = 1.5920
(2) (ν1 + ν2) / 2 = 68.36
(3) n8 = 1.8830
n9 = 1.7618
(4) ν8 = 40.76
ν9 = 26.52
(5) r8 / f = 0.34
(6) f89 / f = 1.51

  The aberration diagrams of the first example are shown in FIG. 2A is a diagram showing various aberrations in the infinitely focused state, and FIG. 2B is a diagram showing various aberrations in the finite distance in-focus state. In each aberration diagram, NA is the numerical aperture, Y is the image height, d is the d-line (λ = 587.6 nm), g is the g-line (λ = 435.6 nm), and C is the C-line (λ = 656.3 nm) and F represents the F line (λ = 486.1 nm), respectively. In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. Further, in the aberration diagrams showing the spherical aberration, the solid line shows the spherical aberration, and the broken line shows the sine condition (sine condition). The description of this aberration diagram is the same in the following examples. As is apparent from the respective aberration diagrams, in the first example, it is understood that various aberrations are favorably corrected in each in-focus state, and excellent imaging performance is obtained.

[Second Embodiment]
FIG. 3 is a diagram showing the configuration of the taking lens ZL2 according to the second embodiment of the present invention. In the photographic lens ZL2 of FIG. 3, the first lens component G1 is composed of a positive meniscus lens L1 having a convex surface facing the object side, and the second lens component G2 is composed of a positive meniscus lens L2 having a convex surface facing the object side. The third lens component G3 is composed of a negative meniscus lens L3 having a convex surface facing the object side, and the front lens component G4 (fourth lens component) is composed of a negative meniscus lens L4 having a convex surface facing the object side. The cemented lens G56 is configured by bonding a rear negative lens component G5 (fifth lens component) composed of a biconcave lens L5 and a rear positive lens component G6 (sixth lens component) composed of a biconvex lens L6. The seventh lens component G7 is composed of a positive meniscus lens L7 having a convex surface facing the image side, and the cemented lens G89 is an eighth lens G8 composed of a biconvex lens L8. Constructed by bonding the ninth lens G9 consisting of a negative meniscus lens L9 having a convex surface directed toward the image side.

  Focusing from a long distance to a short distance is performed by dividing the entire taking lens ZL into three groups of lens components G1 to G4, lens components G5 to G7, and a cemented lens G89, and separately feeding them to the object side. Is called. Here, the aperture stop S moves along the optical axis together with the front negative lens component G4 during focusing. In addition, the moving speed at the time of focusing is configured to move faster in the order of the lens components G1 to G4, the lens components G5 to G7, and the cemented lens G89.

  Table 4 below lists values of specifications of the second embodiment.

(Table 4)
f = 32.0
F.NO = 1.2
2ω = 29.9
Image height = 8.5
Total length = 54.4

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 37.0000 3.53 1.5924 68.36
2 234.8452 0.10
3 24.4487 3.93 1.5924 68.36
4 79.8238 0.10
5 19.5757 5.63 1.8160 46.62
6 19.2626 1.57
7 48.1037 0.80 1.6727 32.10
8 10.9088 4.05
9 0.0000 (d1) (Aperture stop)
10 -12.2741 0.80 1.6989 30.13
11 59.2157 5.08 1.8830 40.76
12 -19.1818 0.10
13 -122.2510 2.09 1.7550 52.32
14 -42.5780 (d2)
15 38.5205 4.67 1.8830 40.76
16 -25.0706 4.03 1.7618 26.52
17 -223.2770 (d3)
18 0.0000 1.00 1.5168 64.10
19 0.0000 1.50
20 0.0000 1.87 1.5168 64.10
21 0.0000 0.40
22 0.0000 0.70 1.5168 64.10
23 0.0000 0.50

  In the second embodiment, the axial air distance d1 between the front negative lens component G4 and the rear negative lens component G5, the axial air distance d2 between the seventh lens component G7 and the eighth lens component G8, and the ninth The axial air gap d3 between the lens component G9 and the filter group FL changes during focusing. Table 5 below shows the variable interval at infinity and at a shooting magnification of 1 / 13.6.

(Table 5)
Magnification at infinity 1 / 13.6
d1 4.23 4.62
d2 0.1 1.9
d3 7.59 9.52

  Table 6 below shows values corresponding to the conditional expressions in the second embodiment.

(Table 6)
(1) (n1 + n2) / 2 = 1.5920
(2) (ν1 + ν2) / 2 = 68.36
(3) n8 = 1.8830
n9 = 1.7618
(4) ν8 = 40.76
ν9 = 26.52
(5) r8 / f = 0.34
(6) f89 / f = 1.03

  FIG. 4 shows various aberrations of the second example. 4A is a diagram showing various aberrations in the infinitely focused state, and FIG. 4B is a diagram showing various aberrations in the finite distance in-focus state. As is apparent from this aberration diagram, it can be seen that in the second example, various aberrations are satisfactorily corrected and excellent imaging performance is obtained in each in-focus state.

[Third embodiment]
FIG. 5 is a diagram showing the configuration of the taking lens ZL3 according to the third embodiment of the present invention. In the photographic lens ZL3 of FIG. 5, the first lens component G1 is composed of a positive meniscus lens L1 having a convex surface facing the object side, and the second lens component G2 is composed of a positive meniscus lens L2 having a convex surface facing the object side. The third lens component G3 is composed of a positive meniscus lens L3 having a convex surface facing the object side, and the front negative lens component G4 (fourth lens component) is composed of a negative meniscus lens L4 having a convex surface facing the object side. The cemented lens G56 is configured by bonding a rear negative lens component G5 (fifth lens component) composed of a biconcave lens L5 and a rear positive lens component G6 (sixth lens component) composed of a biconvex lens L6. The seventh lens component G7 is composed of a biconvex positive lens L7, and the cemented lens G89 is composed of an eighth lens G8 composed of a biconvex lens L8 and a biconcave lens L9. Constructed by bonding the ninth lens G9.

  Focusing from a long distance to a short distance is performed by dividing the entire taking lens ZL into three groups of lens components G1 to G4, lens components G5 to G7, and a lens component G89, and separately feeding them to the object side. Is called. Here, the aperture stop S moves along the optical axis together with the front negative lens component G4 during focusing. In addition, the moving speed at the time of focusing is configured to move faster in the order of the lens components G1 to G4, the lens components G5 to G7, and the cemented lens G89.

  Table 7 below lists values of specifications of the third example.

(Table 7)
f = 32.0
F.NO = 1.2
2ω = 29.9
Image height = 8.5
Total length = 57.2

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 40.3452 3.29 1.4970 81.54
2 223.9692 0.10
3 28.3068 3.84 1.5924 68.36
4 127.2352 0.10
5 20.6648 5.85 1.8160 46.62
6 23.4794 1.55
7 46.6282 1.47 1.6727 32.10
8 11.4452 4.07
9 0.0000 (d1) (Aperture stop)
10 -12.5129 1.00 1.6989 30.13
11 77.8330 6.92 1.8830 40.76
12 -21.0744 0.10
13 174.0421 3.16 1.7550 52.32
14 -39.3712 (d2)
15 34.3162 4.76 1.8830 40.76
16 -36.3229 1.30 1.7618 26.52
17 61.4220 (d3)
18 0.0000 1.00 1.5168 64.10
19 0.0000 1.50
20 0.0000 1.87 1.5168 64.1
21 0.0000 0.40
22 0.0000 0.70 1.5168 64.1
23 0.0000 0.50

  In the third embodiment, the axial air distance d1 between the front negative lens component G4 and the rear negative lens component G5, the axial air distance d2 between the seventh lens component G7 and the eighth lens component G8, and the ninth The axial air gap d3 between the lens component G9 and the filter group FL changes during focusing. Table 8 below shows the variable intervals at infinity and at a magnification of 1 / 13.6.

(Table 8)
Magnification at infinity 1 / 13.6
d1 5.02 5.96
d2 0.10 2.72
d3 8.64 9.77

  Table 9 below shows values corresponding to the conditional expressions in the third embodiment.

(Table 9)
(1) (n1 + n2) / 2 = 1.5447
(2) (ν1 + ν2) / 2 = 74.95
(3) n8 = 1.8830
n9 = 1.7618
(4) ν8 = 40.76
ν9 = 26.52
(5) r8 / f = 0.36
(6) f89 / f = 1.78

  The aberration diagrams of the third example are shown in FIG. FIG. 6A is a diagram illustrating various aberrations in the infinitely focused state, and FIG. 6B is a diagram illustrating various aberrations in the finite distance focused state. As is apparent from this aberration diagram, it can be seen that in the third example, various aberrations are satisfactorily corrected and excellent imaging performance is obtained in each in-focus state.

[Fourth embodiment]
FIG. 7 is a diagram showing the configuration of the taking lens ZL4 according to the fourth embodiment of the present invention. In the photographing lens ZL4 of FIG. 7, the first lens component G1 is composed of a positive meniscus lens L1 having a convex surface facing the object side, and the second lens component G2 is composed of a positive meniscus lens L2 having a convex surface facing the object side. The third lens component G3 is composed of a positive meniscus lens L3 having a convex surface facing the object side, and the front negative lens component G4 (fourth lens component) is composed of a negative meniscus lens L4 having a convex surface facing the object side. The cemented lens G56 is configured by bonding a rear negative lens component G5 (fifth lens component) composed of a biconcave lens L5 and a rear positive lens component G6 (sixth lens component) composed of a biconvex lens L6. The seventh lens component G7 is composed of a biconvex positive lens L7, and the cemented lens G89 is composed of an eighth lens G8 composed of a biconvex lens L8 and a biconcave lens L9. Constructed by bonding the ninth lens G9.

  Focusing from a long distance to a short distance is performed by dividing the entire taking lens ZL into three groups of lens components G1 to G4, lens components G5 to G7, and a lens component G89, and separately feeding them to the object side. Is called. Here, the aperture stop S moves along the optical axis together with the front negative lens component G4 during focusing. In addition, the moving speed at the time of focusing is configured to move faster in the order of the lens components G1 to G4, the lens components G5 to G7, and the cemented lens G89.

  Table 10 below lists values of specifications of the fourth example.

(Table 10)
f = 32.0
F.NO = 1.2
2ω = 29.9
Image height = 8.5
Total length = 58.7

Surface number Curvature radius Surface spacing Refractive index Abbe number
1 45.1295 3.37 1.5924 68.36
2 1436.3282 0.10
3 31.5479 3.39 1.5924 68.36
4 112.1635 0.10
5 21.2165 5.13 1.8160 46.62
6 22.6838 2.49
7 91.6166 0.80 1.6477 33.79
8 13.6500 3.88
9 0.0000 (d1) (Aperture stop)
10 -13.6776 0.80 1.6989 30.13
11 309.5468 6.84 1.8830 40.76
12 -21.5615 0.10
13 184.5845 2.86 1.7550 52.32
14 -44.1935 (d2)
15 38.4025 5.26 1.8830 40.76
16 -33.3169 4.61 1.7618 26.52
17 68.0862 (d3)
18 0.0000 1.00 1.5168 64.10
19 0.0000 1.50
20 0.0000 1.87 1.5168 64.10
21 0.0000 0.40
22 0.0000 0.70 1.5168 64.10
23 0.0000 0.50

  In the fourth embodiment, the axial air distance d1 between the front negative lens component G4 and the rear negative lens component G5, the axial air distance d2 between the seventh lens component G7 and the 89th lens component G89, and the 89th lens. The axial air distance d3 between the lens component G89 and the filter group FL changes during focusing. Table 11 below shows the variable intervals at infinity and at a shooting magnification of 1 / 13.6.

(Table 11)
Magnification at infinity 1 / 13.6
d1 4.43 5.21
d2 0.10 2.31
d3 8.47 9.95

  Table 12 below shows values corresponding to the conditional expressions in the fourth embodiment.

(Table 12)
(1) (n1 + n2) / 2 = 1.5920
(2) (ν1 + ν2) / 2 = 68.36
(3) n8 = 1.8830
n9 = 1.7618
(4) ν8 = 40.76
ν9 = 26.52
(5) r8 / f = 0.43
(6) f89 / f = 1.87

  The aberration diagrams of the fourth example are shown in FIG. FIG. 8A is a diagram of various aberrations in the infinite focus state, and FIG. 8B is a diagram of various aberrations in the finite distance focus state. As is apparent from this aberration diagram, in the fourth example, it is understood that various aberrations are satisfactorily corrected and excellent imaging performance is obtained in each in-focus state.

It is sectional drawing which shows the structure of the imaging lens by 1st Example. FIG. 3A is a diagram illustrating various aberrations of the first example, in which FIG. 3A is a diagram illustrating aberrations in an infinite focus state, and FIG. It is sectional drawing which shows the structure of the imaging lens by 2nd Example. FIG. 5A is a diagram illustrating various aberrations of the second example, in which FIG. 9A is a diagram illustrating aberrations in an infinitely focused state, and FIG. It is sectional drawing which shows the structure of the photographic lens by 3rd Example. FIG. 5A is a diagram illustrating various aberrations of the third example, in which FIG. 9A is a diagram illustrating aberrations in an infinite focus state, and FIG. It is sectional drawing which shows the structure of the photographic lens by 4th Example. FIG. 6A is a diagram illustrating various aberrations of the fourth example, in which FIG. 9A is a diagram illustrating aberrations in an infinitely focused state, and FIG. The electronic still camera which mounts the photographic lens concerning this invention is shown, (a) is a front view, (b) is a rear view. It is sectional drawing along the AA 'line of Fig.9 (a).

Explanation of symbols

ZL (ZL1 to ZL4) Shooting lens G1 First lens component G2 Second lens component G3 Third lens component G4 Front negative lens component (fourth lens component)
G5 Rear negative lens component (5th lens component)
G6 Rear positive lens component (sixth lens component) G56 Joint lens G8 Positive lens G9 Negative lens G89 Joint lens S Aperture stop 1 Electronic still camera (optical equipment)

Claims (17)

A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
The cemented lens disposed on the most image side , wherein the refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, the refractive index of the second lens component with respect to the d-line is n2, and the Abbe number is ν2. When the refractive index of the positive lens with respect to the d-line is n8, the Abbe number is ν8, the refractive index of the cemented lens arranged closest to the image side with respect to the d-line of the negative lens is n9, and the Abbe number is ν9 , The following formula (n1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
n8> n9
ν8> ν9
Shooting lens that satisfies the above conditions. A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
Between the second lens component and the cemented lens, in order from the object side, a front negative lens component having a negative refractive power, an aperture stop, a rear negative lens component having a negative refractive power, and a positive A rear positive lens component having refractive power,
The refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, the refractive index of the second lens component with respect to the d-line is n2, the Abbe number is ν2, and the image side surface of the front negative lens component Where r8 is the radius of curvature and f is the focal length of the entire photographic lens system , the following equation (n1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
0.3 <r8 / f <0.5
Shooting lens that satisfies the above conditions. A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
Between the second lens component and the cemented lens, in order from the object side, a front negative lens component having a negative refractive power, an aperture stop, a rear negative lens component having a negative refractive power, and a positive A rear positive lens component having refractive power,
A meniscus third lens component with a convex surface facing the object side between the second lens component and the front negative lens component;
The front negative lens component is a meniscus fourth lens component having a convex surface facing the object side, and the rear negative lens component is a biconcave fifth lens component;
When the refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, the refractive index of the second lens component with respect to the d-line is n2, and the Abbe number is ν2, the following formula (n1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
Shooting lens that satisfies the above conditions. A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
When the refractive index for the d-line of the first lens component is n1, the Abbe number is ν1, the refractive index for the d-line of the second lens component is n2, and the Abbe number is ν2, the following formula (n1 + n2) / 2 ≧ 1.592
(Ν1 + ν2) /2≧68.36
Shooting lens that satisfies the above conditions. A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
When the refractive index for the d-line of the first lens component is n1, the Abbe number is ν1, the refractive index for the d-line of the second lens component is n2, and the Abbe number is ν2, the following formula (n1 + n2) / 2 ≧ 1.5447
( Ν1 + ν2 ) /2≧74.95
Shooting lens that satisfies the above conditions. The refractive index of the cemented lens arranged on the most image side with respect to the d-line of the positive lens is n8, the Abbe number is ν8, and the refractive index of the cemented lens arranged on the most image side with respect to the d-line of the negative lens is When n9 and the Abbe number are ν9, the following formula n8> n9
ν8> ν9
The photographing lens according to claim 2 or 3 , wherein When the radius of curvature of the image side surface of the front negative lens component is r8 and the focal length of the entire photographing lens system is f, the following expression 0.3 <r8 / f <0.5
The photographic lens according to claim 3 , wherein Between the second lens component and the cemented lens,
A front negative lens component having negative refractive power, an aperture stop, a rear negative lens component having negative refractive power, and a rear positive lens component having positive refractive power in order from the object side. The photographing lens according to any one of 1 , 4, and 5 . Wherein between the second lens component and the front negative lens component, the imaging lens according to claim 2 or 8 having a third lens component having a meniscus shape with a convex surface directed toward the object side. 10. The seventh lens component according to claim 2, further comprising a seventh lens component having a positive refractive power, between the sixth lens component as the rear positive lens component and the cemented lens. Shooting lens. The photographing lens according to any one of claims 2, 3, and 6 to 10, wherein the rear negative lens component and the rear positive lens component are bonded cemented lenses. It said first lens component and said second lens component, respectively, the imaging lens according to any one of claims 1 to 11 is a meniscus shape with a convex surface facing the object side. The imaging according to any one of claims 1 to 12, wherein the cemented lens and the other lens arranged closest to the image side are configured to move along the optical axis at different speeds during focusing. lens. When the focal length of the cemented lens arranged closest to the image side is f89, and the focal length of the entire photographing lens system is f, the following expression 1 <f89 / f <2
The photographic lens according to any one of claims 1 to 13, which satisfies the following condition. Most the positive lens component arranged the cemented lens on the image side, the imaging lens according to any one of claims 1 to 14 is a biconvex shape. Optical apparatus equipped with the imaging lens according to any one of claims 1 to 15. A first lens component having a positive refractive power and a second lens component having a positive refractive power in order from the object side on the most object side;
On the most image side, it has a cemented lens in which a positive lens and a negative lens are bonded in order from the object side,
The cemented lens disposed on the most image side, wherein the refractive index of the first lens component with respect to the d-line is n1, the Abbe number is ν1, the refractive index of the second lens component with respect to the d-line is n2, and the Abbe number is ν2. When the refractive index of the positive lens with respect to the d-line is n8, the Abbe number is ν8, the refractive index of the cemented lens arranged closest to the image side with respect to the d-line of the negative lens is n9, and the Abbe number is ν9, Next formula
(N1 + n2) / 2> 1.49
(Ν1 + ν2) / 2> 60
n8> n9
ν8> ν9
An imaging method using a photographic lens that satisfies the above conditions .

Images