JP6881604B2 - Optical system and optical equipment - Google Patents

Description

The present invention relates to optical systems and optical instruments .

In recent years, the number of pixels of image pickup devices used in image pickup devices such as digital cameras and video cameras has been increasing. A photographing lens provided in an imaging device using such an imaging element has good chromatic aberration in addition to reference aberrations (single wavelength aberrations) such as spherical aberration and coma, so that there is no color bleeding of an image in a white light source. It is desired that the lens has a high resolution and is corrected to the above. In particular, in the correction of chromatic aberration, it is desirable that the secondary spectrum is satisfactorily corrected in addition to the primary achromaticity. As a means for correcting chromatic aberration, for example, a method using a resin material having anomalous dispersibility (see, for example, Patent Document 1) is known. As described above, with the recent increase in the number of pixels of the image pickup device, a photographing lens in which various aberrations are satisfactorily corrected is desired.

Japanese Unexamined Patent Publication No. 2016-194609

The optical system according to the first aspect includes an aperture diaphragm and a positive lens arranged on the image side of the aperture diaphragm and satisfying the following conditional expression.
ndP2 + (0.01425 × νdP2) <2.12
18.0 <νdP2 <35.0
0.702 <θgFP2 + (0.00316 × νdP2)
ndP2- (0.020 × νdP2-1.080) × νdP2 <14.500
However, ndP2: the refractive index of the positive lens with respect to the d-line ν dP2: the Abbe number θgFP2 based on the d-line of the positive lens: the partial dispersion ratio of the positive lens, and the refractive index of the positive lens with respect to the g-line is ngP2. When the refractive index of the positive lens with respect to the F line is nFP2 and the refractive index of the positive lens with respect to the C line is nCP2, θgFP2 = (ngP2-nFP2) / (nFP2-nCP2) defined by the following equation.

The optical system according to the second aspect includes an aperture diaphragm and a positive lens arranged on the image side of the aperture diaphragm and satisfying the following conditional expression.
ndP2 + (0.01425 × νdP2) <2.07
23.5 <νdP2 <35.0
0.702 <θgFP2 + (0.00316 × νdP2)
1.86 <ndP2 + (0.00787 × νdP2)
However, ndP2: the refractive index of the positive lens with respect to the d line.
νdP2: Abbe number based on the d line of the positive lens
θgFP2: Partial dispersion ratio of the positive lens, the refractive index of the positive lens with respect to the g line is ngP2, the refractive index of the positive lens with respect to the F line is nFP2, and the refractive index of the positive lens with respect to the C line is nCP2. When you do, it is defined by the following equation
θgFP2 = (ngP2-nFP2) / (nFP2-nCP2)

The optical device according to the third aspect includes the above optical system.

It is a lens block diagram in the infinity focusing state of the optical system which concerns on 1st Example. It is a diagram of various aberrations in the infinity focusing state of the optical system according to the first embodiment. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 2nd Example. It is a diagram of various aberrations in the infinity focusing state of the optical system according to the second embodiment. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 3rd Example. 6 (A), 6 (B), and 6 (C) show various aspects of the optical system according to the third embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 4th Example. 8 (A), 8 (B), and 8 (C) show various aspects of the optical system according to the fourth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 5th Example. 10 (A), 10 (B), and 10 (C) show various aspects of the optical system according to the fifth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 6th Example. 12 (A), 12 (B), and 12 (C) show various aspects of the optical system according to the sixth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 7th Example. It is a diagram of various aberrations in the infinity focusing state of the optical system according to the seventh embodiment. It is a lens block diagram in the infinity focusing state of the optical system which concerns on 8th Example. It is a diagram of various aberrations in the infinity focusing state of the optical system according to the eighth embodiment. It is a figure which shows the structure of the camera provided with the optical system which concerns on this embodiment. It is a flowchart which shows the manufacturing method of the optical system which concerns on this embodiment.

Hereinafter, the optical system and the optical device according to the present embodiment will be described with reference to the drawings. First, a camera (optical device) provided with an optical system according to the present embodiment will be described with reference to FIG. As shown in FIG. 17, the camera 1 is a digital camera provided with an optical system according to the present embodiment as a photographing lens 2. In the camera 1, the light from an object (subject) (not shown) is collected by the photographing lens 2 and reaches the image sensor 3. As a result, the light from the subject is captured by the image sensor 3 and recorded as a subject image in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1. This camera may be a mirrorless camera or a single-lens reflex type camera having a quick return mirror.

As shown in FIG. 1, the optical system LS (1) as an example of the optical system (photographing lens) LS according to the present embodiment has an aperture diaphragm S and the following conditional expression arranged on the image side of the aperture diaphragm S. It has a positive lens (L22) that satisfies (1) to (3).

ndP2 + (0.01425 × νdP2) <2.12 ・ ・ ・ (1)
18.0 <νdP2 <35.0 ... (2)
0.702 <θgFP2 + (0.00316 × νdP2) ・ ・ ・ (3)
However, ndP2: the refractive index of the positive lens with respect to the d-line ν dP2: the Abbe number θgFP2 based on the d-line of the positive lens, and the partial dispersion ratio of the positive lens. When the refractive index for the F line is nFP2 and the refractive index for the C line of the positive lens is nCP2, θgFP2 = (ngP2-nFP2) / (nFP2-nCP2) defined by the following equation.
The Abbe number νdP2 based on the d-line of the positive lens is defined by the following equation: νdP2 = (ndP2-1) / (nFP2-nCP2).

According to the present embodiment, in the correction of chromatic aberration, it is possible to obtain an optical system in which the secondary spectrum is satisfactorily corrected in addition to the primary achromaticity, and an optical device provided with this optical system. The optical system LS according to the present embodiment may be the optical system LS (2) shown in FIG. 3, the optical system LS (3) shown in FIG. 5, or the optical system LS (4) shown in FIG. The optical system LS (5) shown in 9 may be used. Further, the optical system LS according to the present embodiment may be the optical system LS (6) shown in FIG. 11, the optical system LS (7) shown in FIG. 13, or the optical system LS (8) shown in FIG. ..

The conditional expression (1) defines an appropriate relationship between the refractive index of the positive lens with respect to the d-line and the Abbe number with respect to the d-line. By satisfying the conditional equation (1), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticity).

If the corresponding value of the conditional expression (1) exceeds the upper limit value, for example, the Petzval sum becomes small, which makes it difficult to correct the curvature of field, which is not preferable. By setting the upper limit value of the conditional expression (1) to 2.11, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the upper limit of the conditional expression (1) is preferably 2.10, 2.09, 2.08, 2.07, and further 2.06.

Conditional expression (2) defines an appropriate range of Abbe numbers with respect to the d-line of a positive lens. By satisfying the conditional expression (2), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticity).

If the corresponding value of the conditional expression (2) exceeds the upper limit value, for example, it becomes difficult to correct the axial chromatic aberration in the subgroup on the image side of the aperture stop S, which is not preferable. By setting the upper limit value of the conditional expression (2) to 32.5, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (2) is set to 32.0, 31.5, 31.0, 30.5, 30.0, and further 29.5. Is preferable.

If the corresponding value of the conditional expression (2) is less than the lower limit value, for example, it becomes difficult to correct the axial chromatic aberration in the subgroup on the image side of the aperture stop S, which is not preferable. By setting the lower limit value of the conditional expression (2) to 20.0, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the lower limit of the conditional expression (2) is set to 23.0, 23.5, 24.0, 24.5, 25.0, 25.5, 26.0. , 26.5, 27.0, 27.5, and more preferably 27.7.

The conditional expression (3) appropriately defines the anomalous dispersibility of the positive lens. By satisfying the conditional expression (3), in the correction of chromatic aberration, in addition to the first-order achromaticity, the second-order spectrum can be satisfactorily corrected.

When the corresponding value of the conditional expression (3) is less than the lower limit value, the abnormal dispersibility of the positive lens becomes small, and it becomes difficult to correct the chromatic aberration. By setting the lower limit value of the conditional expression (3) to 0.704, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (3) is preferably 0.708, 0.710, 0.712, and further 0.715.

In the optical system of the present embodiment, it is desirable that the positive lens satisfies the following conditional expression (4).
1.83 <ndP2 + (0.00787 × νdP2) ・ ・ ・ (4)

The conditional expression (4) defines an appropriate relationship between the refractive index of the positive lens with respect to the d-line and the Abbe number with respect to the d-line. By satisfying the conditional equation (4), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticity).

If the corresponding value of the conditional expression (4) is less than the lower limit value, for example, the refractive index of the positive lens becomes small, which makes it difficult to correct the reference aberration, particularly the spherical aberration, which is not preferable. By setting the lower limit value of the conditional expression (4) to 1.84, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the lower limit of the conditional expression (4) is 1.85 and further 1.86.

In the optical system of the present embodiment, the positive lens may satisfy the following conditional expression (2-1) and conditional expression (4-1).
18.0 <νdP2 <26.5 ... (2-1)
1.83 <ndP2 + (0.00787 × νdP2) ・ ・ ・ (4-1)

The conditional expression (2-1) is the same expression as the conditional expression (2), and the same effect as the conditional expression (2) can be obtained. By setting the upper limit value of the conditional expression (2-1) to 26.0, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the upper limit of the conditional expression (2-1) is 25.5 and further 25.0. On the other hand, by setting the lower limit value of the conditional expression (2-1) to 23.5, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the lower limit of the conditional expression (2-1) is 24.0 and further 24.5.

The conditional expression (4-1) is the same expression as the conditional expression (4), and the same effect as the conditional expression (4) can be obtained. By setting the lower limit value of the conditional expression (4-1) to 1.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the lower limit of the conditional expression (4-1) is 1.92 and further 1.94.

In the optical system of the present embodiment, the positive lens may satisfy the following conditional expression (2-2) and conditional expression (4-2).
25.0 <νdP2 <35.0 ... (2-2)
1.83 <ndP2 + (0.00787 × νdP2) ・ ・ ・ (4-2)

The conditional expression (2-2) is the same expression as the conditional expression (2), and the same effect as the conditional expression (2) can be obtained. By setting the upper limit value of the conditional expression (2-2) to 32.5, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the upper limit of the conditional expression (2-2) is 31.5 and further 29.5. On the other hand, by setting the lower limit value of the conditional expression (2-2) to 26.2, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable that the lower limit of the conditional expression (2-2) is 26.7 and further 27.7.

The conditional expression (4-2) is the same expression as the conditional expression (4), and the same effect as the conditional expression (4) can be obtained. By setting the lower limit value of the conditional expression (4-2) to 1.84, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (4-2) to 1.85.

In the optical system of the present embodiment, it is desirable that the positive lens satisfies the following conditional expression (5).
DP2> 0.80 ・ ・ ・ (5)
However, DP2: thickness [mm] on the optical axis of the positive lens

Conditional expression (5) defines an appropriate range of thickness on the optical axis of a positive lens. By satisfying the conditional equation (5), various aberrations such as coma and chromatic aberration (axial chromatic aberration and chromatic aberration of magnification) can be satisfactorily corrected.

If the corresponding value of the conditional expression (5) is less than the lower limit value, it becomes difficult to correct various aberrations such as coma and chromatic aberration (axial chromatic aberration and chromatic aberration of magnification), which is not preferable. By setting the lower limit value of the conditional expression (5) to 0.90, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of the present embodiment, it is preferable that the lower limit of the conditional expression (5) is 1.00, 1.10, 1.20, and further 1.30.

The optical system of the present embodiment has an image-side lens arranged most on the image side, the aperture diaphragm S is arranged on the object side of the image-side lens, the positive lens is on the object side of the image-side lens, and the aperture diaphragm S is. It is desirable to arrange it closer to the image side. Thereby, various aberrations such as coma aberration and chromatic aberration (axial chromatic aberration and magnifying chromatic aberration) can be satisfactorily corrected.

In the optical system of the present embodiment, the positive lens is preferably a glass lens. As a result, it is possible to obtain a lens that is resistant to aging and environmental changes such as temperature changes, as compared with the case where the material is resin.

In the optical system of the present embodiment, it is desirable that the positive lens satisfies the following conditional expressions (6) to (7).
ndP2 <1.63 ... (6)
ndP2- (0.040 × νdP2-2.470) × νdP2 <39.809 ... (7)

The conditional expression (6) defines an appropriate range of the refractive index of the positive lens with respect to the d-line. By satisfying the conditional equation (6), various aberrations such as coma and chromatic aberration (axial chromatic aberration and chromatic aberration of magnification) can be satisfactorily corrected.

If the corresponding value of the conditional expression (6) exceeds the upper limit value, it becomes difficult to correct various aberrations such as coma and chromatic aberration (axial chromatic aberration and chromatic aberration of magnification), which is not preferable. By setting the upper limit value of the conditional expression (6) to 1.62, the effect of the present embodiment can be made more reliable.

The conditional expression (7) defines an appropriate relationship between the refractive index of the positive lens with respect to the d-line and the Abbe number with respect to the d-line. By satisfying the conditional equation (7), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticity).

If the corresponding value of the conditional expression (7) exceeds the upper limit value, for example, the Petzval sum becomes small, which makes it difficult to correct the curvature of field, which is not preferable. By setting the upper limit value of the conditional expression (7) to 39.800, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (7) is set to 39.500, 39.000, 38.500, 38.000, 37.500, and further 36.800. Is preferable.

In the optical system of the present embodiment, it is desirable that the positive lens satisfies the following conditional expression (8).
ndP2- (0.020 × νdP2-1.080) × νdP2 <16.260 ... (8)

The conditional expression (8) defines an appropriate relationship between the refractive index of the positive lens with respect to the d-line and the Abbe number with respect to the d-line. By satisfying the conditional expression (8), it is possible to satisfactorily correct reference aberrations such as spherical aberration and coma, and correct primary chromatic aberration (achromaticity).

If the corresponding value of the conditional expression (8) exceeds the upper limit value, for example, the Petzval sum becomes small, which makes it difficult to correct the curvature of field, which is not preferable. By setting the upper limit value of the conditional expression (8) to 16.240, the effect of the present embodiment can be made more reliable. In order to further ensure the effect of this embodiment, the upper limit of the conditional expression (8) is set to 16.000, 15.800, 15.500, 15.300, 15.000, 14.800, 14.500. , 14.000, and more preferably 13.500.

Subsequently, the method for manufacturing the above-mentioned optical system LS will be outlined with reference to FIG. First, the aperture diaphragm S and at least a positive lens are arranged on the image side of the aperture diaphragm S (step ST1). At this time, each lens is arranged in the lens barrel so that at least one of the positive lenses arranged on the image side of the aperture diaphragm S satisfies the above conditional expressions (1) to (3) and the like (step). ST2). According to such a manufacturing method, in the correction of chromatic aberration, it is possible to manufacture an optical system in which the secondary spectrum is satisfactorily corrected in addition to the primary achromaticity.

Hereinafter, the optical system LS according to the embodiment of the present embodiment will be described with reference to the drawings. 1, FIG. 3, FIG. 5, FIG. 7, FIG. 9, FIG. 11, FIG. 13, and FIG. 15 show the configuration of the optical system LS {LS (1) to LS (8)} according to the first to eighth embodiments. And is a cross-sectional view showing the refractive power distribution. In the cross-sectional views of the optical systems LS (1) to LS (2) according to the first to second embodiments and the optical systems LS (7) to LS (8) according to the seventh to eighth embodiments, the focusing lens group The direction of movement when focusing on a short-range object from infinity is indicated by an arrow with the letters "focus". In the cross-sectional views of the optical systems LS (3) to LS (6) according to the third to sixth embodiments, the optical axis of each lens group when the magnification is changed from the wide-angle end state (W) to the telephoto end state (T). The direction of movement along is indicated by an arrow.

In FIGS. 1, 3, 5, 7, 7, 9, 11, 13, and 15, each lens group is represented by a combination of reference numerals G and numbers, and each lens is designated by a combination of reference numerals L and numbers. Represents. In this case, in order to prevent the types and numbers of the symbols and numbers from becoming large and complicated, the lens group and the like are represented by independently using combinations of the symbols and numbers for each embodiment. Therefore, even if the same combination of reference numerals and numbers is used between the examples, it does not mean that they have the same configuration.

Tables 1 to 8 are shown below. Among them, Table 1 is the first embodiment, Table 2 is the second embodiment, Table 3 is the third embodiment, Table 4 is the fourth embodiment, and Table 5 is the first embodiment. 5 Examples, Table 6 is a table showing 6th Example, Table 7 is a table showing 7th Example, and Table 8 is a table showing each specification data in the 8th Example. In each embodiment, d-line (wavelength λ = 587.6 nm), g-line (wavelength λ = 435.8 nm), C-line (wavelength λ = 656.3 nm), and F-line (wavelength λ =) are calculated as aberration characteristics. 486.1 nm) is selected.

In the [Overall Specifications] table, f is the focal length of the entire lens system, FNO is the F number, 2ω is the angle of view (unit is ° (degrees), and ω is the half angle of view), and Y is the image height. Shown. TL indicates the distance from the frontmost surface of the lens to the final surface of the lens on the optical axis at infinity, plus BF, and BF is the image from the final surface of the lens on the optical axis at infinity. The distance to the surface I (back focus) is shown. When the optical system is a variable magnification optical system, these values are shown for each of the wide-angle end (W), intermediate focal length (M), and telephoto end (T) in each variable magnification state.

In the [Lens Specifications] table, the surface numbers indicate the order of the optical surfaces from the object side along the direction in which the light beam travels, and R is the radius of curvature of each optical surface (the surface whose center of curvature is located on the image side). (Positive value), D is the distance on the optical axis from each optical surface to the next optical surface (or image surface), nd is the refractive index of the material of the optical member with respect to the d line, and νd is optical. The Abbe number with respect to the d-line of the material of the member is shown, and θgF is the partial dispersion ratio of the material of the optical member. “∞” of the radius of curvature indicates a plane or an aperture, and (aperture S) indicates an aperture stop S. The description of the refractive index of air nd = 1.00000 is omitted. When the optical surface is aspherical, the surface number is marked with * a, and the column of radius of curvature R indicates the paraxial radius of curvature.

The refractive index of the material of the optical member with respect to the g line (wavelength λ = 435.8 nm) is ng, the refractive index of the material of the optical member with respect to the F line (wavelength λ = 486.1 nm) is nF, and the refractive index of the material of the optical member is C. Let nC be the refractive index for the line (wavelength λ = 656.3 nm). At this time, the partial dispersion ratio θgF of the material of the optical member is defined by the following equation (A).

θgF = (ng-nF) / (nF-nC) ... (A)

In the table of [Aspherical surface data], the shape of the aspherical surface shown in [Lens specifications] is shown by the following equation (B). X (y) is the distance (zag amount) along the optical axis direction from the tangent plane at the aspherical apex to the position on the aspherical surface at the height y, and R is the radius of curvature of the reference sphere (near-axis radius of curvature). , Κ indicates the conical constant, and Ai indicates the i-th order aspherical coefficient. "E-n" indicates " ^{x10 -n".} For example, 1.234E-05 = 1.234 × 10 ^-5 . The second-order aspherical coefficient A2 is 0, and the description thereof is omitted.

X (y) = (y ² / R) / {1 + (1-κ × y ² / R ² ) ^1/2 } + A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰ … (B)

When the optical system is not a variable magnification optical system, f indicates the focal length of the entire lens system and β indicates the photographing magnification as [variable interval data at the time of short-distance shooting]. In addition, the table of [Variable Interval Data for Short-distance Shooting] shows the surface spacing with the surface number in which the surface spacing is "variable" in [Lens Specifications] corresponding to each focal length and shooting magnification. ..

When the optical system is a variable magnification optical system, the [variable interval data at the time of variable magnification shooting] corresponds to each variable magnification state of the wide-angle end (W), the intermediate focal length (M), and the telephoto end (T). Lens specifications] indicates the surface spacing at the surface number where the surface spacing is "variable". In addition, the table of [lens group data] shows the starting surface (the surface closest to the object) and the focal length of each lens group.

The table of [Conditional expression corresponding values] shows the values corresponding to each conditional expression.

Hereinafter, in all the specification values, "mm" is generally used for the focal length f, the radius of curvature R, the plane spacing D, other lengths, etc., unless otherwise specified, but the optical system is expanded proportionally. Alternatively, it is not limited to this because the same optical performance can be obtained even if the proportional reduction is performed.

The description of the table so far is common to all the examples, and the duplicate description below is omitted.

(First Example)
The first embodiment will be described with reference to FIGS. 1 to 2 and Table 1. FIG. 1 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the first embodiment of the present embodiment. The optical system LS (1) according to the first embodiment is composed of a first lens group G1 having a negative refractive power and a second lens group G2 having a positive refractive power arranged in order from the object side. There is. When focusing from an infinity object to a short-distance (finite distance) object, the second lens group G2 moves toward the object along the optical axis. The aperture diaphragm S is arranged in the second lens group G2. The symbol (+) or (-) attached to each lens group symbol indicates the refractive power of each lens group, and this also applies to all the following examples.

The first lens group G1 includes a negative meniscus lens L11 having a convex surface facing the object side, a biconvex positive lens L12, a biconcave negative lens L13, and a biconvex positive lens arranged in order from the object side. It is composed of a bonded lens composed of a lens L14 and a biconcave negative lens L15. The negative lens L13 has an aspherical lens surface on the image side.

The second lens group G2 is a junction lens composed of a biconvex positive lens L21 arranged in order from the object side, a positive meniscus lens L22 with a convex surface facing the object side, and a negative meniscus lens L23 with a convex surface facing the object side. A junction lens consisting of a biconcave negative lens L24 and a biconvex positive lens L25, a flat positive lens L26 with a convex surface facing the image side, and a positive meniscus lens L27 with a concave surface facing the object side. , Consists of. The image plane I is arranged on the image side of the second lens group G2. An aperture diaphragm S is arranged between the positive lens L21 and the positive meniscus lens L22 in the second lens group G2. In this embodiment, the positive meniscus lens L27 of the second lens group G2 corresponds to the image side lens, and the positive meniscus lens L22 of the second lens group G2 is a positive lens satisfying the conditional equations (1) to (3) and the like. Applicable. The positive lens L26 has an aspherical lens surface on the image side.

Table 1 below lists the values of the specifications of the optical system according to the first embodiment.

(Table 1)
[Overall specifications]
f 28.773
FNO 1.8796
2ω 75.3311
Y 21.60
TL 131.9655
BF 36.457
[Lens specifications]
Surface number R D nd ν d θ gF
1 57.6700 1.7000 1.713000 53.94 0.5441
2 23.6385 10.630
3 360.0000 3.4200 1.846660 23.78
4 -149.5844 2.1000
5 -91.6110 1.7000 1.487490 70.31
6 34.8169 0.1000 1.520500 51.02
7 * a 31.0734 7.4700
8 54.5000 8.5700 1.834000 37.18
9 -43.5000 1.7000 1.749714 24.66 0.6272
10 475.5646 D10 (variable)
11 41.6500 6.2000 1.589130 61.24
12 -79.7342 8.8800
13 ∞ 1.0000 (Aperture S)
14 71.7000 1.3000 1.659398 26.87 0.6323
15 165.1470 1.0000 1.672700 32.19
16 41.0000 6.0900
17 -19.3844 1.5200 1.805180 25.46
18 400.0000 2.4200 1.772500 49.65
19 -67.0000 0.6000
20 ∞ 3.0800 1.729160 54.66
21 -50.8920 0.2000 1.520500 51.02
22 * a -37.6986 1.1400
23 -98.0000 5.2100 1.834810 42.72 0.5651
24-26.8452 2.3629
25 ∞ BF
[Aspherical data]
Side 7 κ = 0.000
A4 = -2.99E-06, A6 = -2.39E-08, A8 = 1.13E-10, A10 = -3.69E-13
Side 22 κ = 0.000
A4 = 2.03E-05, A6 = 4.37E-09, A8 = 1.85E-10, A10 = -1.33E-12
[Variable interval data for short-distance shooting]
Infinity in-focus state Short-distance in-focus state
f = 28.7734 β = -0.2174
D10 9.5660 2.3031
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.87
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7172
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 1.3000
Conditional expression (6)
ndP2 = 1.659398
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.830
Conditional expression (8)
ndP2- (0.020 × νdP2-1.080) × νdP2 = 12.920

FIG. 2 is a diagram of various aberrations of the optical system according to the first embodiment in the infinity in-focus state. In each aberration diagram, FNO indicates an F number and Y indicates an image height. The spherical aberration diagram shows the F number or numerical aperture value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the coma aberration diagram shows the value of each image height. .. d is the d line (wavelength λ = 587.6 nm), g is the g line (wavelength λ = 435.8 nm), C is the C line (wavelength λ = 656.3 nm), and F is the F line (wavelength λ = 486.1 nm). ) Are shown respectively. In the astigmatism diagram, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. In the aberration diagrams of each of the following examples, the same reference numerals as those of the present embodiment will be used, and duplicate description will be omitted.

From each aberration diagram, it can be seen that the optical system according to the first embodiment has various aberrations satisfactorily corrected and has excellent imaging performance.

(Second Example)
The second embodiment will be described with reference to FIGS. 3 to 4 and Table 2. FIG. 3 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the second embodiment of the present embodiment. In the optical system LS (2) according to the second embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refraction are arranged in order from the object side. It is composed of a third lens group G3 having power. When focusing from an infinity object to a short-distance (finite distance) object, the second lens group G2 moves toward the image side along the optical axis. The aperture diaphragm S is arranged near the object side of the third lens group G3, and is fixed to the image plane I at the time of focusing, similarly to the first lens group G1 and the third lens group G3.

The first lens group G1 includes a protective glass HG having an extremely weak refractive power, a biconvex positive lens L11, a biconvex positive lens L12, and a biconcave negative lens L13 arranged in order from the object side. The lens is composed of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side.

The second lens group G2 is composed of a biconcave negative lens L21 arranged in order from the object side, a positive meniscus lens L22 with a concave surface facing the object side, and a junction lens consisting of a biconcave negative lens L23. Will be done.

The third lens group G3 includes a first subgroup G31 having a positive refractive power, a second subgroup G32 having a negative power, and a third subgroup having a positive power, which are arranged in order from the object side. It has G33. The first subgroup G31 is composed of a biconvex positive lens L31 arranged in order from the object side and a junction lens composed of a negative meniscus lens L32 with a concave surface facing the object side. The second subgroup G32 is composed of a junction lens composed of a biconvex positive lens L33 and a biconcave negative lens L34 arranged in order from the object side, and a biconcave negative lens L35. The third subgroup G33 is composed of a biconvex positive lens L36, a biconvex positive lens L37, and a biconcave negative lens L38 arranged in order from the object side. In this embodiment, the negative lens L38 of the third lens group G3 corresponds to the image side lens, and the positive lens L33 of the third lens group G3 corresponds to the positive lens satisfying the conditional equations (1) to (3) and the like. .. The second subgroup G33 of the third lens group G3 constitutes a vibration-proof lens group (subgroup) that can move in a direction perpendicular to the optical axis, and the displacement of the imaging position due to camera shake or the like (on the image plane I). Image blur) is corrected. A fixed diaphragm (flare cut diaphragm) Sa is arranged between the second subgroup G32 and the third subgroup G33 in the third lens group G3.

The image plane I is arranged on the image side of the third lens group G3. An optical filter FL that can be inserted and removed is arranged between the third lens group G3 and the image plane I. As the interchangeable optical filter FL, for example, an NC filter (neutral color filter), a color filter, a polarizing filter, an ND filter (dimming filter), an IR filter (infrared cut filter) and the like are used.

Table 2 below lists the values of the specifications of the optical system according to the second embodiment.

(Table 2)
[Overall specifications]
f 392.000
FNO 2.881
2ω 6.245
Y 21.63
TL 396.319
BF 74.502
[Lens specifications]
Surface number R D nd ν d θ gF
1 1200.37020 5.000 1.51680 63.88 0.536
2 1199.78950 1.000
3 250.71590 16.414 1.43385 95.25 0.540
4 -766.97150 45.000
5 158.99440 18.720 1.43385 95.25 0.540
6 -400.00000 2.261
7 -377.29180 6.000 1.61266 44.46 0.564
8 461.79700 95.451
9 70.05760 4.000 1.79500 45.31 0.560
10 47.57190 11.944 1.49782 82.57 0.539
11 1223.84820 D11 (variable)
12 -546.41280 2.500 1.80610 40.97 0.569
13 76.73180 6.996
14 -241.81680 4.500 1.65940 26.87 0.633
15 -56.62280 2.500 1.48749 70.32 0.529
16 234.80990 D16 (variable)
17 ∞ 5.100 (Aperture S)
18 95.57020 6.000 1.75500 52.33 0.548
19 -75.36620 1.800 1.80809 22.74 0.629
20 -757.80810 4.500
21 279.80870 4.700 1.74971 24.66 0.627
22 -82.76070 1.800 1.59319 67.90 0.544
23 50.04470 3.390
24 -226.07440 1.800 1.83481 42.73 0.565
25 105.63280 4.250
26 ∞ 0.250
27 105.07290 3.700 1.69680 55.52 0.543
28 -158.46840 0.100
29 92.25180 4.000 1.72047 34.71 0.583
30 -129.17240 1.800 1.92119 23.96 0.620
31 404.52160 7.500
32 ∞ 1.500 1.51680 63.88 0.536
33 ∞ BF
[Variable interval data for short-distance shooting]
Infinity in-focus state Short-distance in-focus state
f = 392.000 β = -0.173
D11 13.847 29.047
D16 33.495 18.295
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.101
Conditional expressions (2), (2-1), (2-2)
νdP2 = 24.66
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7049
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 x νdP2) = 1.944
Conditional expression (5)
DP2 = 4.700
Conditional expression (6)
ndP2 = 1.74971
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 34.836
Conditional expression (8)
ndP2- (0.020 x νdP2-1.080) x νdP2 = 12.721

FIG. 4 is a diagram of various aberrations of the optical system according to the second embodiment in the infinity in-focus state. From each aberration diagram, it can be seen that the optical system according to the second embodiment has various aberrations corrected well and has excellent imaging performance.

(Third Example)
The third embodiment will be described with reference to FIGS. 5 to 6 and Table 3. FIG. 5 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the third embodiment of the present embodiment. In the optical system LS (3) according to the third embodiment, the first lens group G1 having a negative refractive power, the second lens group G2 having a positive refractive power, and the negative refractive power arranged in order from the object side. It is composed of a third lens group G3 having a force and a fourth lens group G4 having a positive refractive power. When the magnification is changed from the wide-angle end state (W) to the telephoto end state (T), the first to fourth lens groups G1 to G4 move in the directions indicated by the arrows in FIG. The aperture diaphragm S is arranged between the second lens group G2 and the third lens group G3, and moves along the optical axis together with the third lens group G3 at the time of scaling.

The first lens group G1 includes a negative meniscus lens L11 having a convex surface facing the object side, a biconcave negative lens L12, a biconcave negative lens L13, and a biconvex positive lens arranged in order from the object side. It is composed of a lens L14. The negative meniscus lens L11 has aspherical lens surfaces on both sides. The negative lens L13 has an aspherical lens surface on the image side.

The second lens group G2 is a junction lens composed of a negative meniscus lens L21 having a convex surface facing the object side and a positive meniscus lens L22 having a convex surface facing the object side arranged in order from the object side, and a biconvex positive lens L23. And consists of.

The third lens group G3 includes a junction lens composed of a biconvex positive lens L31 and a biconcave negative lens L32 arranged in order from the object side, a negative meniscus lens L33 with a concave surface facing the object side, and biconvex. It is composed of a positive lens L34 having a shape. In this embodiment, the positive lens L34 of the third lens group G3 corresponds to a positive lens satisfying the conditional expressions (1) to (3) and the like. Further, in this embodiment, when focusing from an infinity object to a short-distance (finite distance) object, the negative meniscus lens L33 and the positive lens L34 of the third lens group G3 move toward the image side along the optical axis. ..

The fourth lens group G4 includes a junction lens composed of a biconvex positive lens L41 and a biconcave negative lens L42 arranged in order from the object side, a biconvex positive lens L43, and a concave surface facing the object side. It is composed of a positive meniscus lens L44 and a junction lens consisting of a negative lens L45 with a concave surface facing the object side. The image plane I is arranged on the image side of the fourth lens group G4. In this embodiment, the negative lens L45 of the fourth lens group G4 corresponds to the image side lens. The negative lens L45 has an aspherical lens surface on the image side.

Table 3 below lists the values of the specifications of the optical system according to the third embodiment.

(Table 3)
[Overall specifications]
Variable ratio 2.07
WMT
f 16.65 24.00 34.43
FNO 4.12 4.12 4.18
2ω 107.58 83.63 63.19
Y 21.60 21.60 21.60
TL 168.91 162.86 167.14
BF 39.00 48.62 65.18
[Lens specifications]
Surface number R D nd ν d θ gF
1 * a 145.31700 3.000 1.76684 46.78 0.5576
2 * a 18.85670 9.851
3-326.23140 1.550 1.88300 40.66 0.5668
4 85.38900 4.225
5 -53.70640 1.500 1.88300 40.66 0.5668
6 51.34430 0.400 1.55389 38.09 0.5928
7 * a 63.00250 2.357
8 53.19070 6.801 1.69895 30.13 0.6021
9 -42.56470 D9 (variable)
10 36.83870 1.050 1.84666 23.80 0.6215
11 18.12050 4.250 1.62004 36.40 0.5833
12 63.71820 0.100
13 32.00210 4.533 1.51696 52.40 0.5544
14 -68.04600 D14 (variable)
15 ∞ 3.263 (Aperture S)
16 745.37430 2.545 1.62004 36.40 0.5833
17 -30.65950 1.000 1.88300 40.66 0.5668
18 69.53870 2.388
19 -23.28320 0.800 1.88300 40.66 0.5668
20 -69.51460 0.150
21 86.42750 4.549 1.65940 26.87 0.6327
22 -29.47240 D22 (variable)
23 35.16640 10.376 1.49782 82.57 0.5386
24 -24.74900 1.100 1.83400 37.18 0.5778
25 1215.04870 0.100
26 38.11360 9.425 1.49782 82.57 0.5386
27 -36.58240 0.100
28 -136.80970 8.294 1.67221 54.76 0.5503
29 -20.68170 1.600 1.80610 40.97 0.5688
30 * a -654.08670 BF
[Aspherical data]
First side κ = 1.0000
A4 = 3.82E-06, A6 = 3.24E-09, A8 = 0.00E + 00, A10 = 0.00E + 00
Second side κ = 1.0000
A4 = -2.08E-05, A6 = 0.00E + 00, A8 = 0.00E + 00, A10 = 0.00E + 00
Side 7 κ = 1.0000
A4 = 1.57E-05, A6 = -3.97E-08, A8 = 3.99E-11, A10 = 0.00E + 00
Side 30 κ = 1.0000
A4 = 1.77E-05, A6 = 1.40E-08, A8 = 0.00E + 00, A10 = 0.00E + 00
[Variable interval data during variable magnification shooting]
WMT
D9 31.875 14.203 2.000
D14 3.000 8.901 13.460
D22 9.727 5.825 1.200
[Lens group data]
Focal length
G1 1 -23.700
G2 10 42.200
G3 15 -84.900
G4 23 60.900
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.87
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7176
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 4.549
Conditional expression (6)
ndP2 = 1.65940
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.830
Conditional expression (8)
ndP2- (0.020 × νdP2-1.080) × νdP2 = 12.920

6 (A), 6 (B), and 6 (C) show various aspects of the optical system according to the third embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. From each aberration diagram, it can be seen that the optical system according to the third embodiment has various aberrations satisfactorily corrected and has excellent imaging performance.

(Fourth Example)
The fourth embodiment will be described with reference to FIGS. 7 to 8 and Table 4. FIG. 7 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the fourth embodiment of the present embodiment. In the optical system LS (4) according to the fourth embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refractive power arranged in order from the object side. It is composed of a third lens group G3 having a force, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. When the magnification is changed from the wide-angle end state (W) to the telephoto end state (T), the first to fourth lens groups G1 to G4 move in the directions indicated by the arrows in FIG. The aperture diaphragm S is arranged on the most object side of the third lens group G3, and moves along the optical axis together with the third lens group G3 at the time of scaling.

The first lens group G1 is a junction lens composed of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side arranged in order from the object side, and a convex surface facing the object side. It is composed of a positive meniscus lens L13.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, and a positive meniscus lens L22 having a concave surface facing the object side, which are arranged in order from the object side. It is composed of L23 and a negative meniscus lens L24 with a concave surface facing the object side. The negative meniscus lens L21 has an aspherical lens surface on the object side. The negative meniscus lens L24 has an aspherical lens surface on the image side.

The third lens group G3 is a junction lens composed of a biconvex positive lens L31 arranged in order from the object side, a positive meniscus lens L32 with a concave surface facing the object side, and a negative meniscus lens L33 with a concave surface facing the object side. It is composed of a negative meniscus lens L34 having a convex surface facing the object side and a junction lens consisting of a biconvex positive lens L35. In this embodiment, the positive lens L31 of the third lens group G3 corresponds to a positive lens satisfying the conditional expressions (1) to (3) and the like. The positive lens L35 has an aspherical lens surface on the image side.

The fourth lens group G4 is composed of a junction lens composed of a biconcave negative lens L41 and a biconvex positive lens L42 arranged in order from the object side, and a negative meniscus lens L43 with a convex surface facing the object side. Will be done. In this embodiment, focusing is performed by moving the negative meniscus lens L43 of the fourth lens group G4 along the optical axis.

The fifth lens group G5 is composed of a biconvex positive lens L51 arranged in order from the object side and a negative meniscus lens L52 with a convex surface facing the object side. The image plane I is arranged on the image side of the fifth lens group G5. In this embodiment, the negative meniscus lens L52 of the fifth lens group G5 corresponds to the image side lens.

Table 4 below lists the values of the specifications of the optical system according to the fourth embodiment.

(Table 4)
[Overall specifications]
Variable ratio 7.85
WMT
f 24.720 58.064 194.000
FNO 3.6 5.5 6.5
2ω 85.516 38.972 12.120
Y 21.60 21.60 21.60
TL 149.034 171.725 204.028
BF 40.17156 40.17154 40.17152
[Lens specifications]
Surface number R D nd ν d θ gF
1 92.15372 1.50000 1.893278 29.92 0.5973
2 50.45119 5.86351 1.49782 82.57 0.5386
3 287.2377 0.50000
4 52.85439 5.29710 1.754987 52.34 0.5545
5 179.2157 D5 (variable)
6 * a 192.5648 1.50000 1.76684 46.78 0.5576
7 14.39735 9.14834
8 -53.9422 1.50000 1.804 46.6 0.5575
9 -159.834 0.50004
10 -458.262 3.37612 1.80809 22.74 0.6287
11 -32.7306 1.09499
12 -25.8208 1.50010 1.76818 49.12 0.5602
13 * a -71.2139 D13 (variable)
14 ∞ 0.50251 (Aperture S)
15 25.10727 4.79424 1.659398 26.87 0.6327
16 -47.2953 0.53134
17 -63.4845 2.79326 1.754941 52.34 0.5546
18 -22.633 1.50000 1.949938 29.37 0.5987
19 -1891.64 0.50000
20 22.49872 2.24749 1.949963 29.37 0.5987
21 12.7943 8.00000 1.519269 65.98 0.5332
22 * a -31.4383 D22 (variable)
23 -31.6877 3.00000 1.78738 34.67 0.5867
24 25.83264 6.67641 1.765346 49.1 0.5602
25 -37.7488 0.50640
26 95.74988 1.50570 1.755164 52.29 0.5546
27 27.40248 D27 (variable)
28 43.74094 5.00269 1.615395 37.55 0.5811
29 -91.144 0.50000
30 83.67357 1.50000 1.755 52.34 0.5545
31 26.73611 BF
[Aspherical data]
Side 6 κ = 2.000
A4 = 2.65541E-06, A6 = -2.66829E-09, A8 = 2.269004E-12, A10 = -1.11750E-14
Page 13 κ = 0.000
A4 = -1.10122E-05, A6 = -3.09432E-08, A8 = 1.57986E-10, A10 = -9.22034E-13
Side 22 κ = 0.0427
A4 = 2.11546E-05, A6 = -8.86580E-09, A8 = -7.04018E-10, A10 = 2.78728E-12
[Variable interval data during variable magnification shooting]
WMT
D5 0.50226 15.6917 48.17765
D13 34.74901 15.99244 0.50004
D22 0.55612 4.10818 8.61444
D27 1.71514 24.42039 35.22397
[Lens group data]
Focal length
G1 1 97.0173
G2 6 -17.8186
G3 14 24.5561
G4 23 -38.3045
G5 28 328.1997
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.87
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7176
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 4.794424
Conditional expression (6)
ndP2 = 1.659398
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.830
Conditional expression (8)
ndP2- (0.020 × νdP2-1.080) × νdP2 = 12.920

8 (A), 8 (B), and 8 (C) show various aspects of the optical system according to the fourth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. From each aberration diagram, it can be seen that the optical system according to the fourth embodiment has various aberrations corrected well and has excellent imaging performance.

(Fifth Example)
A fifth embodiment will be described with reference to FIGS. 9 to 10 and Table 5. FIG. 9 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the fifth embodiment of the present embodiment. In the optical system LS (5) according to the fifth embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refractive power arranged in order from the object side. It is composed of a third lens group G3 having a force, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When the magnification is changed from the wide-angle end state (W) to the telephoto end state (T), the second lens group G2 and the fourth lens group G4 move in the directions indicated by the arrows in FIG. 9, respectively. The aperture diaphragm S is arranged near the object side of the third lens group G3, and at the time of scaling, the image plane I is similar to the first lens group G1, the third lens group G3, and the fifth lens group G5. Is fixed to.

The first lens group G1 is a junction lens composed of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12 arranged in order from the object side, and a positive meniscus lens L13 having a convex surface facing the object side. And consists of.

The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a concave shape, and a positive meniscus lens L23 having a convex surface facing the object side, which are arranged in order from the object side. It is composed of a concave negative lens L24.

The third lens group G3 includes a biconvex positive lens L31 arranged in order from the object side, a flat positive lens L32 with a convex surface facing the object side, and a positive meniscus lens L33 with a convex surface facing the object side. , A biconcave negative lens L34, a biconvex positive lens L35, and a biconcave negative lens L36.

The fourth lens group G4 is a junction lens composed of a biconvex positive lens L41 arranged in order from the object side, a negative meniscus lens L42 having a convex surface facing the object side, and a positive meniscus lens L43 having a convex surface facing the object side. And consists of. In this embodiment, focusing is performed by moving the entire fourth lens group G4 along the optical axis.

The fifth lens group G5 includes a negative meniscus lens L51 arranged in order from the object side and having a convex surface facing the object side, a junction lens consisting of a biconvex positive lens L52 and a biconcave negative lens L53, and an image side. It is composed of a flat negative lens L54 with a concave surface facing the surface, a biconvex positive lens L55, and a positive meniscus lens L56 with a convex surface facing the object side. The image plane I is arranged on the image side of the fifth lens group G5. In this embodiment, the positive meniscus lens L56 of the fifth lens group G5 corresponds to the image side lens, and the positive lens L52 of the fifth lens group G5 corresponds to the positive lens satisfying the conditional expressions (1) to (3) and the like. To do.

Table 5 below lists the values of the specifications of the optical system according to the fifth embodiment.

(Table 5)
[Overall specifications]
Variable ratio 2.74
WMT
f 71.413619 139.954134 195.992207
FNO 2.9 2.9 2.9
2ω 33.679 17.10734 12.20834
Y 21.60 21.60 21.60
TL 245.2 245.2 245.2
BF 53.3 53.3 53.3
[Lens specifications]
Surface number R D nd ν d θ gF
1 126.7377 2.8000 1.950000 29.37 0.600
2 89.1138 9.9000 1.497820 82.57 0.539
3 -1020.1958 0.1000
4 92.2410 7.7000 1.433852 95.25 0.540
5 697.5997 D5 (variable)
6 67.2071 2.4000 1.719990 50.27 0.553
7 33.2108 10.2500
8-131.8697 2.0000 1.618000 63.34 0.541
9 100.8703 2.0000
10 53.8723 4.4000 1.846660 23.78 0.619
11 192.4940 3.5500
12 -73.3376 2.2000 1.603000 65.44 0.539
13 293.3428 D13 (variable)
14 ∞ 2.5000 (Aperture S)
15 581.3263 3.7000 1.834810 42.73 0.565
16 -130.4486 0.2000
17 90.5655 3.8500 1.593190 67.90 0.544
18 ∞ 0.2000
19 52.6779 4.9000 1.497820 82.57 0.539
20 450.4224 2.0436
21 -118.6005 2.2000 2.001000 29.14 0.600
22 173.2673 4.5500
23 114.6393 5.7500 1.902650 35.73 0.580
24 -66.6756 2.2000 1.581440 40.98 0.576
25 41.9887 D25 (variable)
26 57.8460 4.8000 1.497820 82.57 0.539
27 -191.5275 0.1000
28 44.2622 2.0000 1.950000 29.37 0.600
29 28.5009 5.5500 1.593190 67.90 0.544
30 169.0503 D30 (variable)
31 47.8018 1.8000 1.804000 46.60 0.557
32 30.1942 5.1500
33 105.9950 3.3500 1.659398 26.84 0.632
34 -69.1861 1.6000 1.593190 67.90 0.544
35 40.7640 2.5830
36 ∞ 1.6000 1.953750 32.31 0.590
37 57.1830 3.7500
38 71.6966 3.4000 1.593190 67.90 0.544
39 -551.0952 0.1500
40 55.3080 4.2000 1.719990 50.27 0.553
41 445.3842 BF
[Variable interval data during variable magnification shooting]
WMT
D5 2.94202 20.03940 50.94204
D13 50.63064 33.53326 2.63063
D25 16.90451 14.80744 16.89216
D30 2.01033 4.10740 2.02269
[Lens group data]
Focal length
G1 1 143.97421
G2 6 -45.57214
G3 14 94.45728
G4 26 58.18894
G5 31 -109.05105
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.84
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7168
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 3.3500
Conditional expression (6)
ndP2 = 1.659398
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.820
Conditional expression (8)
ndP2- (0.020 × νdP2-1.080) × νdP2 = 12.920

10 (A), 10 (B), and 10 (C) show various aspects of the optical system according to the fifth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. From each aberration diagram, it can be seen that the optical system according to the fifth embodiment has various aberrations satisfactorily corrected and has excellent imaging performance.

(6th Example)
The sixth embodiment will be described with reference to FIGS. 11 to 12 and Table 6. FIG. 11 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the sixth embodiment of the present embodiment. In the optical system LS (6) according to the sixth embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refractive power arranged in order from the object side. It is composed of a third lens group G3 having a force, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. When the magnification is changed from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in the directions indicated by the arrows in FIG. At the time of scaling, the third lens group G3 and the fifth lens group G5 move along the optical axis with the same amount of movement. The aperture diaphragm S is arranged near the object side of the third lens group G3, and moves along the optical axis together with the third lens group G3 at the time of scaling.

The first lens group G1 includes a junction lens consisting of a negative meniscus lens L11 having a convex surface facing the object side and a flat positive lens L12 having a convex surface facing the object side, which are arranged in order from the object side, and a convex surface toward the object side. It is composed of a positive meniscus lens L13 directed toward the lens.

The second lens group G2 has a negative meniscus lens L21 having a convex surface facing the object side, a negative lens L22 having a biconcave shape, a positive lens L23 having a biconvex shape, and a concave surface on the object side, which are arranged in order from the object side. It is composed of a negative meniscus lens L24 directed toward the lens. The negative meniscus lens L21 has an aspherical lens surface on the object side. In this embodiment, when focusing from an infinity object to a short-distance (finite distance) object, the entire second lens group G2 moves toward the object along the optical axis.

The third lens group G3 is a junction lens composed of a positive meniscus lens L31 having a convex surface facing the object side, a negative meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33 arranged in order from the object side. And a biconvex positive lens L34. The positive lens L34 has an aspherical lens surface on the object side.

The fourth lens group G4 is a junction lens composed of a positive meniscus lens L41 having a concave surface facing the object side and a negative lens L42 having both concave shapes arranged in order from the object side, and a positive meniscus lens L43 having a concave surface facing the object side. It is composed of a bonded lens composed of a biconcave negative lens L44 and a concave lens. In this embodiment, the positive meniscus lens L43 of the fourth lens group G4 corresponds to a positive lens satisfying the conditional expressions (1) to (3) and the like.

The fifth lens group G5 is a junction lens composed of a biconvex positive lens L51 arranged in order from the object side, a positive meniscus lens L52 with a concave surface facing the object side, and a negative meniscus lens L53 with a concave surface facing the object side. And consists of. The image plane I is arranged on the image side of the fifth lens group G5. In this embodiment, the negative meniscus lens L53 of the fifth lens group G5 corresponds to the image side lens. The positive lens L51 has an aspherical lens surface on the object side.

Table 6 below lists the values of the specifications of the optical system according to the sixth embodiment.

(Table 6)
[Overall specifications]
Variable ratio 4.09
WMT
f 24.900 50.000 101.900
FNO 4.100 4.100 4.100
2ω 84.743 45.523 23.261
Y 21.60 21.60 21.60
TL 149.910 162.620 182.430
BF 40.185 48.193 58.850
[Lens specifications]
Surface number R D nd ν d θ gF
1 163.16770 1.800 1.84666 23.80 0.622
2 63.11640 8.700 1.60311 60.69 0.541
3 ∞ 0.100
4 47.77580 6.150 1.80400 46.60 0.557
5 108.85110 D5 (variable)
6 * a 137.31600 0.100 1.55389 38.09 0.593
7 78.84000 1.200 1.83481 42.71 0.564
8 13.88400 6.500
9 -29.19600 1.000 1.88300 40.76 0.567
10 57.78220 0.100
11 36.31400 5.300 1.80518 25.42 0.616
12 -26.80660 0.670
13 -19.89480 1.300 1.77250 49.60 0.552
14 -45.63920 D14 (variable)
15 ∞ 0.000 (Aperture S)
16 31.50170 3.500 1.43700 95.00 0.533
17 412.56440 1.200
18 28.92410 1.300 1.78470 26.27 0.613
19 16.85630 7.800 1.48749 70.31 0.529
20 -68.28050 0.150
21 * 50.53390 4.010 1.58313 59.42 0.543
22 -63.50130 D22 (variable)
23 -60.07050 3.200 1.84666 23.80 0.622
24 -16.94620 1.000 1.76200 40.10 0.576
25 61.07170 2.900
26 -104.05170 2.300 1.65940 26.87 0.633
27 -44.45510 1.000 1.83481 42.73 0.565
28 586.44930 D28 (variable)
29 * a 140.20100 0.080 1.55389 38.09 0.593
30 198.01300 6.300 1.58913 61.14 0.541
31 -26.62820 0.150
32 -285.71710 6.700 1.48749 70.23 0.530
33 -21.67090 1.900 1.84666 23.88 0.616
34 -69.60370 BF
Side 6 κ = 1.0000
A4 = 1.70949E-05, A6 = -2.106050E-08, A8 = -4.68699E-11, A10 = 4.42797E-13
Side 21 κ = 1.0000
A4 = -1.20879E-05, A6 = -4.99039E-09, A8 = 1.50865E-11, A10 = -4.88260E-14
Side 29 κ = 1.0000
A4 = -8.63929E-06, A6 = 2.78090E-09, A8 = 1.43178E-11, A10 = -3.56187E-14
[Variable interval data during variable magnification shooting]
WMT
D5 2.442 18.432 34.512
D14 19.113 7.823 0.903
D22 1.993 7.103 10.783
D28 9.767 4.657 0.977
[Lens group data]
Focal length
G1 1 89.877
G2 6 -14.548
G3 15 22.802
G4 23 -28.690
G5 29 49.373
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.87
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7179
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 2.300
Conditional expression (6)
ndP2 = 1.65940
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.830
Conditional expression (8)
ndP2- (0.020 x νdP2-1.080) x νdP2 = 12.920

12 (A), 12 (B), and 12 (C) show various aspects of the optical system according to the sixth embodiment at infinity focusing in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. From each aberration diagram, it can be seen that the optical system according to the sixth embodiment has various aberrations corrected well and has excellent imaging performance.

(7th Example)
A seventh embodiment will be described with reference to FIGS. 13 to 14 and Table 7. FIG. 13 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the seventh embodiment of the present embodiment. In the optical system LS (7) according to the seventh embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refraction are arranged in order from the object side. It is composed of a third lens group G3 having power. When focusing from an infinity object to a short-distance (finite distance) object, the second lens group G2 moves toward the image side along the optical axis. The aperture diaphragm S is arranged near the object side of the third lens group G3, and is fixed to the image plane I at the time of focusing, similarly to the first lens group G1 and the third lens group G3.

The first lens group G1 includes a protective glass HG having an extremely weak refractive power, a biconvex positive lens L11, a biconvex positive lens L12, and a biconcave negative lens L13 arranged in order from the object side. The lens is composed of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side.

The second lens group G2 is composed of a biconcave negative lens L21 arranged in order from the object side, a positive meniscus lens L22 with a concave surface facing the object side, and a junction lens consisting of a biconcave negative lens L23. Will be done.

The third lens group G3 includes a biconvex positive lens L31, a negative meniscus lens L32 with a concave surface facing the object side, a biconvex positive lens L33, and a biconcave negative lens arranged in order from the object side. A junction lens made of L34, a biconcave negative lens L35, a biconvex positive lens L36, a biconvex positive lens L37, and a biconcave negative lens L38, and a concave surface on the object side. It consists of a junction lens consisting of a positive meniscus lens L39 with a concave surface facing the object and a negative meniscus lens L40 with a concave surface facing the object side, a negative meniscus lens L41 with a convex surface facing the object side, and a positive meniscus lens L42 with a convex surface facing the object side. It is composed of a junction lens, a biconcave negative lens L43, a biconvex positive lens L44, and a conjunct lens consisting of a negative meniscus lens L45 with a concave surface facing the object side. In this embodiment, the negative meniscus lens L45 of the third lens group G3 corresponds to the image side lens, and the positive meniscus lens L39 of the third lens group G3 is a positive lens satisfying the conditional equations (1) to (3) and the like. Applicable.

The image plane I is arranged on the image side of the third lens group G3. An optical filter FL that can be inserted and removed is arranged between the negative lens L38 and the positive meniscus lens L39 in the third lens group G3. As the interchangeable optical filter FL, for example, an NC filter (neutral color filter), a color filter, a polarizing filter, an ND filter (dimming filter), an IR filter (infrared cut filter) and the like are used.

Table 7 below lists the values of the specifications of the optical system according to the seventh embodiment.

(Table 7)
[Overall specifications]
f 548.897246
FNO 4.028
2ω 4.529
Y 21.60
TL 421.51451
BF 41.79450
[Lens specifications]
Surface number R D nd ν d θ gF
1 1200.3704 5.0000 1.516800 63.88 0.536
2 1199.7897
3 207.5249 17.5000 1.433843 95.26 0.540
4-1086.1158 44.9000
5 176.7586 18.0000 1.433843 95.26 0.540
6 -399.9688 3.0700
7 -360.7137 6.0000 1.612660 44.46 0.564
8 360.6858 90.0000
9 66.6831 4.0000 1.794997 45.32 0.560
10 46.0960 15.0000 1.497820 82.54 0.539
11 1030.2823 D11 (variable)
12 -1579.9519 2.5000 1.772499 49.68 0.552
13 115.8247 3.3500
14 -274.6805 3.5000 1.846679 23.83 0.620
15 -87.1354 2.4000 1.518229 58.84 0.546
16 65.0724 D16 (variable)
17 ∞ 1.5000 (Aperture S)
18 89.0765 7.6000 1.487490 70.43 0.530
19 -64.1681 1.2000
20 -66.2092 1.9000 1.846679 23.83 0.620
21 -113.6112 5.0000
22 309.3141 3.5000 1.846679 23.83 0.620
23 -136.2550 1.9000 1.593190 67.94 0.544
24 53.6104 3.1000
25 -343.3953 1.9000 1.754999 52.33 0.548
26 94.6723 4.1900
27 117.8519 3.5000 1.772499 49.68 0.552
28 -385.7489 0.1000
29 67.6179 4.5000 1.639999 60.14 0.537
30 -410.4180 1.9000 1.846679 23.83 0.620
31 247.6487 6.5000
32 ∞ 1.5000 1.516800 63.88 0.536
33 ∞ 25.3277
34 -212.6904 6.2000 1.659398 26.84 0.632
35 -34.5457 1.6000 1.850000 27.03 0.609
36 -57.9415 0.1000
37 171.5239 1.7000 1.729160 54.61 0.544
38 20.3538 7.1000 1.581440 40.98 0.576
39 199.2504 3.7000
40 -61.4914 1.7000 1.772500 49.62 0.552
41 80.1566 0.1000
42 39.9229 7.8000 1.581440 40.98 0.576
43 -38.2861 1.7000 1.808090 22.74 0.629
44 -171.6744 BF
[Variable interval data for short-distance shooting]
Infinity in-focus state Short-distance in-focus state
f = 548.89725 β = -0.24282
D11 18.50291 33.77284
D16 38.17937 22.90945
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.042
Conditional expressions (2), (2-1), (2-2)
νdP2 = 26.84
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7168
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 × νdP2) = 1.871
Conditional expression (5)
DP2 = 6.2000
Conditional expression (6)
ndP2 = 1.659398
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 35.820
Conditional expression (8)
ndP2- (0.020 × νdP2-1.080) × νdP2 = 12.920

FIG. 14 is a diagram of various aberrations of the optical system according to the seventh embodiment in the infinity in-focus state. From each aberration diagram, it can be seen that the optical system according to the seventh embodiment has various aberrations corrected well and has excellent imaging performance.

(8th Example)
The eighth embodiment will be described with reference to FIGS. 15 to 16 and Table 8. FIG. 15 is a diagram showing a lens configuration in an infinity-focused state of the optical system according to the eighth embodiment of the present embodiment. In the optical system LS (8) according to the eighth embodiment, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, and the positive refraction are arranged in order from the object side. It is composed of a third lens group G3 having power. When focusing from an infinity object to a short-distance (finite distance) object, the second lens group G2 moves toward the image side along the optical axis. The aperture diaphragm S is arranged near the object side of the third lens group G3, and is fixed to the image plane I at the time of focusing, similarly to the first lens group G1 and the third lens group G3.

The first lens group G1 includes a positive meniscus lens L11 having a convex surface oriented in order from the object side, a junction lens consisting of a biconvex positive lens L12 and a biconcave negative lens L13, and a biconvex positive lens. It is composed of a lens L14, a junction lens including a negative meniscus lens L15 having a convex surface facing the object side, and a positive meniscus lens L16 having a convex surface facing the object side.

The second lens group G2 is a junction lens composed of a positive meniscus lens L21 having a concave surface facing the object side and a negative lens L22 having both concave shapes arranged in order from the object side, and a positive meniscus lens L23 having a concave surface facing the object side. It is composed of a bonded lens composed of a biconcave negative lens L24 and a concave lens.

The third lens group G3 includes a biconvex positive lens L31 arranged in order from the object side, a negative meniscus lens L32 with a concave surface facing the object side, and a positive meniscus lens L33 with a concave surface facing the object side. A junction lens consisting of a convex positive lens L34, a negative meniscus lens L35 with a convex surface facing the object side, a biconvex positive lens L36, a biconcave negative lens L37, and a biconvex positive lens L38. It is composed of a positive meniscus lens L39 having a concave surface facing the object side and a negative meniscus lens L40 having a concave surface facing the object side. In this embodiment, the negative meniscus lens L40 of the third lens group G3 corresponds to the image side lens, and the positive lens L34 of the third lens group G3 corresponds to the positive lens satisfying the conditional equations (1) to (3) and the like. To do. The positive meniscus lens L39 has an aspherical lens surface on the object side.

The image plane I is arranged on the image side of the third lens group G3. An optical filter FL that can be inserted and removed is arranged between the positive meniscus lens L33 and the positive lens L34 in the third lens group G3. As the interchangeable optical filter FL, for example, an NC filter (neutral color filter), a color filter, a polarizing filter, an ND filter (dimming filter), an IR filter (infrared cut filter) and the like are used.

Table 8 below lists the values of the specifications of the optical system according to the eighth embodiment.

(Table 8)
[Overall specifications]
f 388.032537
FNO 4.038
2ω 6.416
Y 21.60
TL 283.53069
BF 53.66784
[Lens specifications]
Surface number R D nd ν d θ gF
1 167.3500 10.6000 1.497820 82.52 0.539
2 2361.5509 0.3000
3 98.4074 20.8000 1.497820 82.52 0.539
4 -306.6320 5.0000 1.772499 49.61 0.552
5 165.4047 20.0000
6 135.6601 9.6000 1.446791 91.03 0.534
7 -731.2064 0.3000
8 71.2883 4.0000 1.754999 52.31 0.547
9 42.3960 16.5000 1.497820 82.52 0.539
10 435.6465 D10 (variable)
11 -1745.8851 5.0000 1.850260 32.35 0.594
12 -78.6510 3.0000 1.639999 60.09 0.538
13 55.9799 6.0000
14 -79.8113 4.2000 1.766840 46.80 0.558
15 -45.8300 2.8000 1.516800 64.10 0.536
16 51.2954 D16 (variable)
17 ∞ 3.2000 (Aperture S)
18 126.0707 5.0000 1.729157 54.66 0.544
19 -81.3057 2.1000
20 -43.1962 3.4000 1.795040 28.54 0.607
21 -104.9670 7.0000
22 -827.9284 5.3000 1.603001 65.47 0.541
23 -52.9313 5.3151
24 ∞ 2.0000 1.516800 64.12 0.536
25 ∞ 9.4440
26 64.5713 5.0000 1.611553 31.26 0.618
27 -280.9473 0.8000
28 350.7347 1.5000 1.804000 46.58 0.557
29 24.0250 5.4000
30 33.9853 9.0000 1.620040 36.30 0.587
31 -23.4510 2.0000 1.882997 40.76 0.567
32 36.4535 8.2000 1.575010 41.49 0.576
33 -45.3865 2.9000
34 * a -91.9573 6.4000 1.589130 61.18 0.539
35 -28.9225 0.5000
36 -33.4300 2.5000 1.882997 40.76 0.567
37 -192.4648 BF
[Aspherical data]
Side 34 κ = 1.0000
A4 = 8.36373E-06, A6 = 2.40160E-09, A8 = 0.00000E + 00, A10 = 0.0000E + 00
[Variable interval data for short-distance shooting]
Infinity in-focus state Short-distance in-focus state
f = 388.03254 β = -0.25415
D10 19.01315 27.19783
D16 15.10916 6.92448
[Conditional expression correspondence value]
Conditional expression (1)
ndP2 + (0.01425 x νdP2) = 2.057
Conditional expressions (2), (2-1), (2-2)
νdP2 = 31.26
Conditional expression (3)
θgFP2 + (0.00316 × νdP2) = 0.7168
Conditional expressions (4), (4-1), (4-2)
ndP2 + (0.00787 x νdP2) = 1.858
Conditional expression (5)
DP2 = 5.000
Conditional expression (6)
ndP2 = 1.611553
Conditional expression (7)
ndP2- (0.040 x ν dP2-2.470) x ν dP2 = 36.513
Conditional expression (8)
ndP2- (0.020 x νdP2-1.080) x νdP2 = 12.605

FIG. 16 is a diagram of various aberrations of the optical system according to the eighth embodiment in the infinity in-focus state. From each aberration diagram, it can be seen that the optical system according to the eighth embodiment has various aberrations corrected well and has excellent imaging performance.

According to each of the above embodiments, it is possible to realize an optical system in which the secondary spectrum is satisfactorily corrected in addition to the primary achromaticity in the correction of chromatic aberration.

Here, each of the above examples shows a specific example of the present invention, and the present invention is not limited thereto.

The following contents can be appropriately adopted as long as the optical performance of the optical system of the present embodiment is not impaired.

The focusing lens group refers to a portion having at least one lens separated by an air interval that changes during focusing. That is, it may be a focusing lens group that focuses on a short-distance object from an infinity object by moving a single lens group or a plurality of lens groups or a partial lens group in the optical axis direction. This focusing lens group can also be applied to autofocus, and is also suitable for driving a motor for autofocus (using an ultrasonic motor or the like).

In the second embodiment of the optical system of the present embodiment, a configuration having an anti-vibration function is shown, but the present application is not limited to this, and a configuration having no anti-vibration function is also possible. Further, other embodiments that do not have the anti-vibration function can also be configured to have the anti-vibration function.

The lens surface may be formed on a spherical surface or a flat surface, or may be formed on an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to processing and assembly adjustment errors can be prevented, which is preferable. Further, even if the image plane is deviated, the depiction performance is less deteriorated, which is preferable.

When the lens surface is aspherical, the aspherical surface is an aspherical surface formed by grinding, a glass mold aspherical surface formed by forming glass into an aspherical shape, or a composite aspherical surface formed by forming resin on the glass surface into an aspherical shape. It doesn't matter which one. Further, the lens surface may be a diffraction surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

An antireflection film having a high transmittance in a wide wavelength range may be applied to each lens surface in order to reduce flare and ghost and achieve high contrast optical performance. As a result, flare and ghost can be reduced, and high-contrast and high optical performance can be achieved.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group I image plane S Aperture aperture

Claims (9)

An optical system having an aperture diaphragm and a positive lens arranged on the image side of the aperture diaphragm and satisfying the following conditional expression.
ndP2 + (0.01425 × νdP2) <2.12
18.0 <νdP2 <35.0
0.702 <θgFP2 + (0.00316 × νdP2)
ndP2- (0.020 × νdP2-1.080) × νdP2 <14.500
However, ndP2: the refractive index of the positive lens with respect to the d-line ν dP2: the Abbe number θgFP2 based on the d-line of the positive lens: the partial dispersion ratio of the positive lens, and the refractive index of the positive lens with respect to the g-line is ngP2. When the refractive index of the positive lens with respect to the F line is nFP2 and the refractive index of the positive lens with respect to the C line is nCP2, θgFP2 = (ngP2-nFP2) / (nFP2-nCP2) defined by the following equation. An optical system having an aperture diaphragm and a positive lens arranged on the image side of the aperture diaphragm and satisfying the following conditional expression.
ndP2 + (0.01425 × νdP2) <2.07
23.5 <νdP2 <35.0
0.702 <θgFP2 + (0.00316 × νdP2)
1.86 <ndP2 + (0.00787 × νdP2)
However, ndP2: the refractive index of the positive lens with respect to the d line.
νdP2: Abbe number based on the d line of the positive lens
θgFP2: Partial dispersion ratio of the positive lens, the refractive index of the positive lens with respect to the g line is ngP2, the refractive index of the positive lens with respect to the F line is nFP2, and the refractive index of the positive lens with respect to the C line is nCP2. When you do, it is defined by the following equation
θgFP2 = (ngP2-nFP2) / (nFP2-nCP2) The optical system according to claim 1, wherein the positive lens satisfies the following conditional expression.
1.83 <ndP2 + (0.00787 × νdP2) The optical system according to claim 1, wherein the positive lens satisfies the following conditional expression.
18.0 <νdP2 <26.5
1.83 <ndP2 + (0.00787 × νdP2) The optical system according to claim 1, wherein the positive lens satisfies the following conditional expression.
25.0 <νdP2 <35.0
1.83 <ndP2 + (0.00787 × νdP2) The optical system according to any one of claims 1 to 5 , wherein the positive lens satisfies the following conditional expression.
DP2> 0.80
However, DP2: thickness [mm] on the optical axis of the positive lens It has an image-side lens placed closest to the image side
The aperture diaphragm is arranged on the object side of the image side lens.
The optical system according to any one of claims 1 to 6 , wherein the positive lens is arranged on the object side of the image side lens and on the image side of the aperture diaphragm. The optical system according to any one of claims 1 to 7 , wherein the positive lens is a glass lens. An optical device including the optical system according to any one of claims 1 to 8.

Images