WO2021241230A1

WO2021241230A1 - Optical system, optical device, and method for manufacturing optical system

Info

Publication number: WO2021241230A1
Application number: PCT/JP2021/018064
Authority: WO
Inventors: 壮基原田
Original assignee: 株式会社ニコン
Priority date: 2020-05-28
Filing date: 2021-05-12
Publication date: 2021-12-02
Also published as: JP7398060B2; JP2023184737A; JPWO2021241230A1

Abstract

Desired is an optical system in which an imaging lens has a large aperture appropriate also for manual focusing and has aberration satisfactorily corrected over the entire focusing region.　The optical system comprises, in order from the object side, a front group having positive refractive power, a stop, and a rear group having positive refractive power as a whole, and satisfies the following conditional expressions. 0.600 < ((h(max)-h(1))/h(1)+(h(max)-h(s))/h(s))×FNo < 2.100 1.500 < f/Bf < 10.000 where h(max) is a height at which a marginal ray becomes the highest in the front group, h(1) is the height of the marginal ray on a first surface, h(s) is the height of the marginal ray at a stop surface, FNo is a maximum aperture when imaging at infinity, f is the focal length of the entire system when imaging at infinity, and Bf is an air equivalent length from a lens final surface to a paraxial image surface on an optical axis when imaging at infinity.

Description

Optical systems, optical instruments, and methods for manufacturing optical systems

The present invention relates to an optical system, an optical device, and a method for manufacturing the optical system.

Conventionally, a photographing lens whose main purpose is to photograph a short-distance object, such as Patent Document 1, is known to be suitable for autofocus. In recent years, in such a photographic lens, a photographic lens having a large aperture that can correct various aberrations more satisfactorily and is also suitable for manual focus has been desired.

Japanese Unexamined Patent Publication No. 63-147124

The optical system according to the first embodiment is composed of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole in order from the object side, and satisfies the following conditional expression.
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo ＜ 2.100
1.500 <f / Bf <10.000
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting,
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.

Further, the optical system according to the second embodiment is composed of a front group having a positive refractive power, a aperture, and a rear group having a positive refractive power as a whole in order from the object side, and is the most among the front groups. The lens group from the lens arranged on the object side to the lens arranged on the most object side with the concave surface facing the object side is defined as the AF group, and the lens group arranged on the image side from the AF group is defined as the AR group. Satisfy the conditional expression.
0.750 <(| 1 / fAF | + | 1 / fAR |) x fA <7,000
However,
fAF: Focal length of AF group during infinite shooting,
fAR: Focal length during infinite shooting of AR group,
fA: Focal length of the front group during infinite shooting.

Further, the optical device according to the third embodiment has the above optical system.

Further, the method for manufacturing an optical system according to the fourth embodiment is configured to include a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole, in order from the object side. It is configured to satisfy the following conditional expression.
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo ＜ 2.100
1.500 <f / Bf <10.000
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting,
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.

It is sectional drawing of the optical system which concerns on 1st Example. It is a diagram of various aberrations at the time of infinity object focusing of the optical system which concerns on 1st Embodiment. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the first embodiment. It is sectional drawing of the optical system which concerns on 2nd Example. It is a diagram of various aberrations at the time of infinity object focusing of the optical system which concerns on 2nd Embodiment. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the second embodiment. It is sectional drawing of the optical system which concerns on 3rd Example. It is a diagram of various aberrations at the time of infinity object focusing of the optical system which concerns on 3rd Example. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the third embodiment. It is sectional drawing of the optical system which concerns on 4th Embodiment. It is a diagram of various aberrations at the time of infinity object focusing of the optical system which concerns on 4th Embodiment. It is a diagram of various aberrations at the time of focusing a short-distance object of the optical system which concerns on 4th Embodiment. It is sectional drawing of the optical system which concerns on 5th Embodiment. It is a diagram of various aberrations at the time of focusing on an infinity object of the optical system according to the fifth embodiment. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the fifth embodiment. It is sectional drawing of the optical system which concerns on 6th Embodiment. It is a diagram of various aberrations at the time of focusing on an infinity object of the optical system according to the sixth embodiment. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the sixth embodiment. It is sectional drawing of the optical system which concerns on 7th Example. It is a diagram of various aberrations at the time of infinity object focusing of the optical system which concerns on 7th Embodiment. It is a diagram of various aberrations at the time of focusing on a short-distance object of the optical system according to the seventh embodiment. It is a figure which shows the structure of the optical device provided with the optical system. It is a flow figure which shows the outline of the manufacturing method of an optical device.

Hereinafter, the optical system, the optical device, and the method for manufacturing the optical system according to the first embodiment and the second embodiment of the present application will be described. However, the present invention is not limited to each of the following embodiments, and any combination may be used. Further, each reference numeral for the figure according to each embodiment may be used independently for each drawing in order to avoid complicated explanation due to an increase in the reference numeral. Therefore, even if they have a reference code common to other drawings, they do not necessarily have a common configuration with other drawings.

First, the optical system according to the first embodiment will be described.
The optical system according to the first embodiment is composed of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole, in order from the object side.

With such a configuration, the optical system of the first embodiment can appropriately correct various aberrations, particularly spherical aberration and coma aberration, from the in-focus state of an infinite object to the in-focus state of a short-range object.

Under such a configuration, the optical system of the first embodiment satisfies the following conditional expression (1).
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo <2.100 (1)
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting.

Here, the "marginal ray" means a ray having the highest incident light among the incident light flux parallel to the optical axis. The "marginal ray height" is the distance from the optical axis to the marginal ray (distance in the direction perpendicular to the optical axis).

The conditional expression (1) is the highest in the front group in terms of the ratio between the difference between the highest marginal ray height in the front group and the marginal ray height in the first diaphragm and the marginal ray height in the first plane. It is a conditional expression that defines the product of the value obtained by adding the ratio of the difference between the marginal ray height and the marginal ray height on the diaphragm surface and the marginal ray height on the diaphragm surface and the open F value. By satisfying the conditional equation (1), the marginal ray passes through the rear lens group at a height equal to or higher than a predetermined height, and spherical aberration, coma aberration, and curvature of field can be satisfactorily corrected in the rear lens group. can.

When the corresponding value of the conditional expression (1) of the first embodiment is less than the lower limit value, the height of the marginal ray on the lens surface on the object side of the rear lens group becomes low, and spherical aberration and coma aberration in the rear lens group. It becomes difficult to correct the problem well. By setting the lower limit of the conditional expression (1) to 0.700, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit values of the conditional expression (1) to 0.800, 0.900, and further 1.000. It was

On the other hand, when the corresponding value of the conditional expression (1) of the first embodiment exceeds the upper limit value, the marginal ray height on the lens surface on the object side of the rear lens group becomes low, and spherical aberration occurs in the rear lens group. It becomes difficult to correct coma aberration well. By setting the upper limit value of the conditional expression (1) to 2.000, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit value of the conditional expression (1) to 1.900, 1.800, and further 1.750. It was

With the above configuration, the optical system of the first embodiment can satisfactorily correct various aberrations from the in-focus state of an infinite object to the in-focus state of a short-range object, and can be used for both auto focus and manual focus. It is possible to realize a suitable large-diameter optical system.

Further, with such a configuration, the optical system of the first embodiment can satisfactorily correct various aberrations, particularly spherical aberration and coma aberration, from the in-focus state of an infinite object to the in-focus state of a short-range object. can.

Further, under such a configuration, the optical system of the first embodiment satisfies the following conditional expression (2).
1.500 <f / Bf <10.000 (2)
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.

The above conditional expression (2) is a conditional expression that defines the ratio between the focal length of the entire system during infinite photography and the air conversion length from the final surface of the lens to the paraxial image plane on the optical axis during infinite photography. .. By satisfying the conditional expression (2), it is possible to satisfy the miniaturization of the entire optical system and good optical performance, and an optical system suitable for a mirrorless camera can be obtained.

When the corresponding value of the conditional expression (2) of the optical system of the first embodiment is less than the lower limit value, the entire optical system becomes large in the radial direction due to the large numerical aperture, and it becomes difficult to correct the curvature of field. By setting the lower limit of the conditional expression (2) to 1.600, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit value of the conditional expression (2) to 1.700, 1.800, 1.900, and further 2.000.

On the other hand, when the corresponding value of the conditional expression (2) of the optical system of the first embodiment exceeds the upper limit value, the diameter of the final lens group becomes large due to the peripheral light beam, and a strong negative power is applied to the optical system for miniaturization. It is required on the rear side of the entire system, and it is particularly difficult to correct spherical aberration. By setting the upper limit value of the conditional expression (2) to 9.000, the effect of the first embodiment can be made more reliable. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit value of the conditional expression (2) to 8,000 and further to 7.500.

Further, it is desirable that the optical system of the first embodiment satisfies the following conditional expression (3).
0.600 <fA / (2 × f) <1.50 (3)
However,
fA: Focal length of the front group during infinite shooting.

The above conditional expression (3) defines the ratio between the focal length of the front group of the first embodiment and the value obtained by doubling the focal length of the entire optical system. By satisfying the conditional expression (3), the symmetry before and after the aperture is improved, the aberration with respect to the angle of view is not enlarged, and the close-range shooting performance can be improved. In particular, spherical aberration and coma aberration during close-range photography can be satisfactorily corrected.

If the corresponding value of the conditional expression (3) of the optical system of the first embodiment exceeds the upper limit value, the refractive power of the front group becomes weak and it becomes difficult to satisfactorily correct spherical aberration and coma. .. By setting the upper limit value of the conditional expression (3) to 1.400, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit values of the conditional expression (3) to 1.300, 1.250, and further 1.200.

On the other hand, if the corresponding value of the conditional expression (3) of the optical system of the first embodiment is less than the lower limit value, the power of the front group becomes strong and it becomes difficult to satisfactorily correct the coma aberration. By setting the lower limit of the conditional expression (3) to 0.650, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit value of the conditional expression (3) to 0.700, further 0.750, and further 0.800.

Further, in the optical system of the first embodiment, the front group is fixed at the time of focusing, and the rear group includes at least one focusing group moving on the optical axis, satisfying the following conditional expression (4). It is desirable to do.
0.500 <(fF × FNo ² ) / f <2.900 (4)
However,
fF: The combined focal length of the entire in-focus group during infinite shooting.

The conditional equation (4) is the product of the combined focal length of the in-focus group at infinity focusing and the square of the open F value at infinity shooting, and the focal length of the entire optical system at infinity focusing. It defines an appropriate power balance with. By satisfying the conditional expression (4), it is possible to improve the close-range shooting performance without expanding various aberrations. In particular, spherical aberration and coma aberration during close-range photography can be satisfactorily corrected.

If the corresponding value of the conditional expression (4) of the optical system of the first embodiment exceeds the upper limit value, the refractive power of the rear group becomes weak and it becomes difficult to satisfactorily correct spherical aberration and coma. .. By setting the upper limit value of the conditional expression (4) to 2.800, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit value of the conditional expression (4) to 2.700, 2.600, and further 2.500.

On the other hand, if the corresponding value of the conditional expression (4) of the optical system of the first embodiment is less than the lower limit value, the power of the rear group becomes strong and it becomes difficult to satisfactorily correct the coma aberration. By setting the lower limit of the conditional expression (4) to 0.600, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit of the conditional expression (4) to 0.700, further 0.800, and further 0.900.

Further, in the optical system of the first embodiment, the front group is fixed at the time of focusing, and the rear group includes at least one focusing group moving on the optical axis, satisfying the following conditional expression (5). It is desirable to do.
0.500 <βF / βB <2000 (5)
However,
βF: Magnification of the in-focus group during infinite shooting,
βB: Magnification of the rear group during infinite shooting.

The conditional expression (5) is a conditional expression that defines the ratio between the magnification of the in-focus group at the time of infinite photography and the magnification of the rear group at the time of infinite photography. Normally, when the distance between lenses or between lens groups is changed, not only spherical aberration but also other aberrations change. When the optical system according to the first embodiment moves along the optical axis, the angle of view variation is reduced by satisfying the conditional equation (5), and coma aberration, curvature of field, astigmatism, and so on. Changes such as chromatic aberration can be suppressed as much as possible.

If the range of the conditional expression (5) of the optical system of the first embodiment is out of range, coma aberration and curvature of field mainly fluctuate due to fluctuations in the angle of view due to focusing, which is not desirable.

By setting the upper limit value of the conditional expression (5) to 1.800, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit values of the conditional expression (5) to 1.600, 1.400, and further 1.300.
Further, by setting the lower limit value of the conditional expression (5) to 0.600, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit values of the conditional expression (5) to 0.650, 0.700, and further 0.720.

Further, it is desirable that the optical system of the first embodiment has at least one negative lens satisfying the following conditional expression (6).
0.600 <θgFLn + 0.0021 × νdLn <0.660 (6)
However,
νdLn: Abbe number for the d line of the negative lens,
θgFLn: Partial dispersion ratio of the g-line and F-line of the negative lens.

Here, the Abbe number νdLn and the partial dispersion ratio θgFLn have a refractive index for the C line (wavelength 656.3 nm) of nC, a refractive index for the d line (wavelength 587.6 nm) of nd, and a refractive index for the F line (wavelength 486.1 nm). When the refractive index is nF and the refractive index for g-line (wavelength 435.8 nm) is ng, they are expressed by the following equations, respectively.
νdLn = (nd-1) / (nF-nC)
θgFLn = (ng-nF) / (nF-nC)

The above conditional expression (6) is a conditional expression that defines the glass material used for the negative lens of the optical system. By having a negative lens that satisfies the conditional expression (6), axial chromatic aberration can be satisfactorily corrected with a small number of lenses.

If the corresponding value of the conditional expression (6) of the optical system of the first embodiment exceeds the upper limit value, the abnormal dispersibility of the negative lens becomes large, and it becomes difficult to correct the axial chromatic aberration. By setting the upper limit value of the conditional expression (6) to 0.659, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit values of the conditional expression (6) to 0.657, 0.656, and further 0.655.

On the other hand, if the corresponding value of the conditional expression (6) of the optical system of the first embodiment is less than the lower limit value, the abnormal dispersibility of the negative lens becomes small, and it becomes difficult to correct the axial chromatic aberration. By setting the lower limit of the conditional expression (6) to 0.610, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit value of the conditional expression (6) to 0.620 and further to 0.630.

Further, it is desirable that the optical system of the first embodiment includes a configuration in which the front group has three or more positive lenses arranged in succession.

As a result, it is possible to suppress the occurrence of aberrations in places where the height of the marginal rays is high, so that spherical aberrations, axial chromatic aberrations, and curvature of field in the entire optical system can be satisfactorily corrected.

Further, in the optical system of the first embodiment, there are two or more negative lenses between the lens on the most object side and the fourth lens in order from the object side of the front group, and among the concave surfaces facing each other. Assuming that the radius of curvature of the image side surface of the negative lens on the object side is r1 and the radius of curvature of the object side surface of the negative lens on the image side is r2, it is desirable that the following conditional expression (7) is satisfied.
0.500 <-r1 / r2 <2000 (7)

In the conditional equation (7), there are two or more negative lenses between the lens on the most object side and the fourth lens in order from the object side of the front group, and the negative lens on the object side of the concave surfaces facing each other. It is a conditional expression that defines the ratio between the radius of curvature of the image side surface and the radius of curvature of the object side surface of the negative lens on the image side.

By satisfying the conditional equation (7), the optical system of the first embodiment contributes to reducing the Petzval sum, satisfactorily corrects curvature of field, and suppresses deterioration of coma aberration and spherical aberration. doing.

By setting the upper limit value of the conditional expression (7) to 1.900, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit value of the conditional expression (7) to 1.800 and further to 1.750.
Further, by setting the lower limit value of the conditional expression (7) to 0.530, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit value of the conditional expression (7) to 0.550 and further to 0.580.

Further, it is desirable that the optical system of the first embodiment satisfies the following conditional expression (8).
0.500 <(r1-r2) /f <5.000 (8)

The conditional expression (8) is a conditional expression that defines the ratio between the difference between the radius of curvature of the concave surface on the object side and the radius of curvature of the concave surface on the image side among the concave surfaces facing each other and the focal length of the entire optical system. Is.

By satisfying the conditional expression (8), the optical system of the first embodiment can further effectively reduce the Petzval sum and correct the curvature of field even better.

By setting the upper limit value of the conditional expression (8) to 4.000, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the upper limit value of the conditional expression (8) to 3.500 and further to 3.200.
Further, by setting the lower limit value of the conditional expression (8) to 0.750, the effect of the first embodiment can be further ensured. Further, in order to further ensure the effect of the first embodiment, it is preferable to set the lower limit values of the conditional expression (8) to 0.900, 1.000, and further 1.100.

Further, it is desirable that the optical system according to the first embodiment has a plurality of groups in which the front group is fixed and the rear group moves on the optical axis at the time of focusing.

As described above, in the optical system according to the first embodiment, the front group is fixed at the time of focusing, and the rear group has a plurality of groups moving on the optical axis, so that spherical aberration, coma aberration, and image are formed. The curvature of field can be corrected even better.

Further, the optical system of the first embodiment includes the F1 group and the F2 group, which are two focusing groups moving on the optical axis, in which the front group is fixed and the rear group moves on the optical axis at the time of focusing, and the following conditions are met. It is desirable to satisfy equation (9).
-0.500 <fF2 / fF1 <0.500 (9)
However,
fF2: Focal length of the F2 group,
fF1: Focal length of the F1 group.

The conditional expression (9) defines an appropriate power balance between the F1 group and the F2 group, which move independently of each other. By satisfying the conditional expression (9), the optical system according to the first embodiment can further suppress the change in image magnification due to focusing, and has extremely good optical performance over the entire focusing region. It is possible to obtain an optical system.
If the upper limit of the conditional expression (9) is exceeded, the refractive power of the F1 group becomes excessive with respect to the F2 group, and it becomes difficult to suppress the aberration fluctuation due to focusing.
In order to further ensure the effect of the conditional expression (9), the upper limit of the conditional expression (9) is preferably 0.400, with 0.300, 0.200, 0.150, and further 0.100. It is more preferable to have.
If it is less than the lower limit of the conditional expression (9), the refractive power of the F2 group becomes excessive with respect to the F1 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire region.
In order to further ensure the effect of the conditional expression (9), the lower limit of the conditional expression (9) is preferably −0.450, −0.400, −0.350, −0.300, and further. -0.250 is more preferable.

Further, the optical system of the first embodiment includes the F1 group and the F2 group, which are two focusing groups moving on the optical axis, in which the front group is fixed and the rear group moves on the optical axis at the time of focusing, and the following conditions are met. It is desirable to satisfy the equation (10).
-0.300 <βF2 / βF1 <1.200 (10)
However,
βF2: Horizontal magnification of the F2 group,
βF1: Horizontal magnification of the F1 group.

The conditional expression (10) defines the ratio of the two focusing groups, the F2 group and the F1 group, which move on the optical axis, at the lateral magnifications. By satisfying the conditional expression (10), the optical system according to the first embodiment can suppress the change in image magnification due to focusing, and has extremely good optical performance over the entire focusing region. You can get the system.
If the upper limit of the conditional expression (10) is exceeded, the lateral magnification of the F2 group becomes excessive with respect to the F1 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire focusing region.
In order to make the effect of the conditional expression (10) more reliable, it is preferable to set the upper limit value of the conditional expression (10) to 1.100, 1.000, 0.900, 0.800, 0.750, 0. More preferably, it is .700, 0.680, and more preferably 0.650.
If it falls below the lower limit of the conditional expression (10), the lateral magnification of the F1 group becomes excessive with respect to the F2 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire focusing region.
In order to further ensure the effect of the conditional expression (10), the lower limit of the conditional expression (10) is preferably −0.250, −0.200, −0.150, −0.100, −. More preferably, it is 0.050, 0.000, and even 0.040.

Further, it is desirable that the optical system of the first embodiment includes a lens having at least one aspherical surface in the rear group.

From this, although the invention of the present application is a large-diameter optical system, spherical aberration can be effectively reduced in particular.

Next, the optical system according to the second embodiment will be described.
The optical system according to the second embodiment is composed of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole, in order from the object side.

With such a configuration, the optical system of the second embodiment can appropriately correct various aberrations, particularly spherical aberration and coma aberration, from the in-focus state of an infinite object to the in-focus state of a short-range object.

Under such a configuration, the optical system of the second embodiment is from the lens arranged on the most object side to the lens arranged on the most object side with the concave surface facing the object side in the front group. The lens group is defined as an AF group, and the lens group arranged on the image side of the AF group is defined as an AR group, and the following conditional expression (11) is satisfied.
0.750 <(| 1 / fAF | + | 1 / fAR |) x fA <7.70 (11)
However,
fAF: Focal length of AF group during infinite shooting,
fAR: Focal length during infinite shooting of AR group,
fA: Focal length of the front group during infinite shooting.

The conditional expression (11) is a conditional expression that defines the product of the sum of the refractive powers of the AF group and the refractive powers of the AR group and the focal length of the front group. By satisfying the conditional expression (11), the marginal ray is once raised high in the group A and lowered in the group B. As a result, the Petzval sum can be reduced, and both spherical aberration and curvature of field in a large-diameter lens can be corrected at the same time.

When the corresponding value of the conditional expression (11) of the second embodiment is less than the lower limit value, the amount of raising it once becomes small, and it becomes impossible to correct both spherical aberration and curvature of field at the same time, and the curvature of field becomes particularly worse. By setting the lower limit of the conditional expression (11) to 0.800, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the lower limit values of the conditional expression (11) to 1.000, 2.000, 2.500, and further 3.000.

On the other hand, if the corresponding value of the conditional expression (11) of the second embodiment exceeds the upper limit value, the spherical aberration will be severely corrected because it is raised too high in the group A. By setting the upper limit of the conditional expression (11) to 6.500, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the upper limit value of the conditional expression (11) to 6,000, 5.500, and further 5.000. It was

With the above configuration, the optical system of the second embodiment can satisfactorily correct various aberrations from the in-focus state of an infinite object to the in-focus state of a short-range object, and can be used for both auto focus and manual focus. It is possible to realize a suitable large-diameter optical system.

Further, with such a configuration, the optical system of the second embodiment can satisfactorily correct various aberrations, particularly spherical aberration and coma aberration, from the in-focus state of an infinite object to the in-focus state of a short-range object. can.

Further, it is desirable that the optical system of the second embodiment has at least one negative lens satisfying the following conditional expression (12).
-0.060 <-NdL-0.011 x νdL + 2.12 <0.034 (12)
24.7 <νdL <58.0 (13)
However,
νdL: Abbe number for the d line of the negative lens,
NdL: Partial dispersion ratio of the g-line and F-line of the negative lens.

Here, as described above, the Abbe number νdL and the partial dispersion ratio NdL have a refractive index of nC for the C line (wavelength 656.3 nm), nd for the d line (wavelength 587.6 nm), and an F line (wavelength 486). When the refractive index for (1 nm) is nF and the refractive index for g-line (wavelength 435.8 nm) is ng, they are expressed by the following equations, respectively.
νdL = (nd-1) / (nF-nC)
NdL = (ng-nF) / (nF-nC)

The above conditional expressions (12) and (13) are conditional expressions that define the glass material used for the negative lens of the optical system. By having a negative lens that satisfies the conditional equations (12) and (13), axial chromatic aberration can be satisfactorily corrected.

If the corresponding value of the conditional expression (12) of the optical system of the second embodiment exceeds the upper limit value, the abnormal dispersibility of the negative lens becomes large, and it becomes difficult to correct the axial chromatic aberration. By setting the upper limit value of the conditional expression (12) to 0.032, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the upper limit values of the conditional expression (12) to 0.030, 0.029, and further 0.028.

On the other hand, if the corresponding value of the conditional expression (12) of the optical system of the second embodiment is less than the lower limit value, the Abbe number of the negative lens becomes large and it becomes difficult to correct the axial chromatic aberration. By setting the lower limit of the conditional expression (12) to −0.055, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the lower limit value of the conditional expression (12) to −0.050 and further to −0.045.

Further, when the corresponding value of the conditional expression (13) of the optical system of the second embodiment exceeds the upper limit value, the abnormal dispersibility of the negative lens becomes small, and it becomes difficult to correct the axial chromatic aberration. By setting the upper limit value of the conditional expression (13) to 57.0, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the upper limit value of the conditional expression (13) to 56.0 and further to 55.5.

On the other hand, if the corresponding value of the conditional expression (13) of the optical system of the second embodiment is less than the lower limit value, the Abbe number of the negative lens becomes small, and it becomes difficult to correct the axial chromatic aberration. By setting the lower limit of the conditional expression (13) to 25.0, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the lower limit values of the conditional expression (13) to 26.0, 27.0, and further 29.5.

Further, it is desirable that the optical system of the second embodiment satisfies the following conditional expression (14).
0.400 <fA / fB <2.5500 (14)
However,
fB: Focal length of the rear group during infinite shooting.

The conditional expression (14) is a conditional expression for defining the ratio between the focal length of the front group and the focal length of the rear group at the time of infinite shooting. By satisfying the conditional equation (14), deterioration of coma aberration and spherical aberration can be suppressed while effectively reducing the Petzval sum, and as a result, curvature of field can be satisfactorily corrected.

If the corresponding value of the conditional expression (14) of the optical system of the second embodiment exceeds the upper limit value, the Petzval sum cannot be effectively reduced, and it becomes difficult to satisfactorily correct the curvature of field. It ends up. By setting the upper limit value of the conditional expression (14) to 2.200, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the upper limit value of the conditional expression (9) to 2.000 and further to 1.800.

On the other hand, if the corresponding value of the conditional expression (14) of the optical system of the second embodiment is less than the lower limit value, spherical aberration and coma aberration will be deteriorated. By setting the lower limit of the conditional expression (14) to 0.450, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the lower limit values of the conditional expression (14) to 0.500, 0.550, and further to 0.600.

Further, in the optical system of the second embodiment, there are two or more negative lenses between the lens on the most object side and the fourth lens in order from the object side of the front group, and among the concave surfaces facing each other. Assuming that the radius of curvature of the image side surface of the negative lens on the object side is r1 and the radius of curvature of the object side surface of the negative lens on the image side is r2, it is desirable that the following conditional expression (15) is satisfied.
-0.500 <(r1 + r2) / (r1-r2) <0.500 (15)

The conditional equation (15) is a condition for defining a scherrer of the radius of curvature of the image side surface of the negative lens on the object side and the radius of curvature of the object side surface of the negative lens on the image side in the concave surfaces facing each other. It is an expression.

By setting the upper limit value of the conditional expression (15) to 0.400, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the upper limit values of the conditional expression (15) to 0.350, 0.300, and further 0.280.
Further, by setting the lower limit value of the conditional expression (15) to −0.400, the effect of the second embodiment can be further ensured. Further, in order to further ensure the effect of the second embodiment, it is preferable to set the lower limit values of the conditional expression (15) to −0.350, −0.300, and further −0.250.

Further, the optical system of the second embodiment includes the F1 group and the F2 group, which are two focusing groups moving on the optical axis, in which the front group is fixed and the rear group moves on the optical axis at the time of focusing, and the following conditions are met. It is desirable to satisfy equation (16).
-0.500 <fF2 / fF1 <0.500 (16)
However,
fF2: Focal length of the F2 group,
fF1: Focal length of the F1 group.

The conditional expression (16) defines an appropriate power balance between the F1 group and the F2 group, which move independently of each other. By satisfying the conditional expression (16), the optical system according to the second embodiment can further suppress the change in image magnification due to focusing, and has extremely good optical performance over the entire focusing region. It is possible to obtain an optical system.
If the upper limit of the conditional expression (16) is exceeded, the refractive power of the F1 group becomes excessive with respect to the F2 group, and it becomes difficult to suppress the aberration fluctuation due to focusing.
In order to further ensure the effect of the conditional expression (16), the upper limit of the conditional expression (16) is preferably 0.400, and 0.300, 0.200, 0.150, and further 0.100. It is more preferable to have.
If it is below the lower limit of the conditional expression (16), the refractive power of the F2 group becomes excessive with respect to the F1 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire region.
In order to further ensure the effect of the conditional expression (16), the lower limit of the conditional expression (16) is preferably −0.450, −0.400, −0.350, −0.300, and further. -0.250 is more preferable.

Further, the optical system of the second embodiment includes the F1 group and the F2 group, which are two focusing groups moving on the optical axis, in which the front group is fixed and the rear group moves on the optical axis at the time of focusing, and the following conditions are met. It is desirable to satisfy equation (17).
-0.300 <βF2 / βF1 <1.200 (17)
However,
βF2: Horizontal magnification of the F2 group,
βF1: Horizontal magnification of the F1 group.

The conditional expression (17) defines the ratio of the two focusing groups, the F2 group and the F1 group, which move on the optical axis, at the lateral magnifications. By satisfying the conditional expression (17), the optical system according to the second embodiment can suppress the change in image magnification due to focusing, and has extremely good optical performance over the entire focusing region. You can get the system.
If the upper limit of the conditional expression (17) is exceeded, the lateral magnification of the F2 group becomes excessive with respect to the F1 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire focusing region.
In order to make the effect of the conditional expression (17) more reliable, it is preferable to set the upper limit value of the conditional expression (17) to 1.100, 1.000, 0.900, 0.800, 0.750, 0. More preferably, it is .700, 0.680, and more preferably 0.650.
If it falls below the lower limit of the conditional expression (17), the lateral magnification of the F1 group becomes excessive with respect to the F2 group, and it becomes difficult to suppress the aberration fluctuation due to focusing over the entire focusing region.
In order to further ensure the effect of the conditional expression (17), the lower limit of the conditional expression (17) is preferably −0.250, −0.200, −0.150, −0.100, −. More preferably, it is 0.050, 0.000, and even 0.040.

The optical device according to this embodiment has an optical system having the above-mentioned configuration. As a result, various aberrations can be satisfactorily corrected from the in-focus state of an infinite object to the in-focus state of a short-range object, and an optical device equipped with a large-diameter optical system suitable for both autofocus and manual focus. Can be realized.

Here, an example of a camera (optical device) equipped with the optical system OL of the present embodiment will be described. FIG. 22 is a diagram showing an example of the configuration of the camera 1 having the lens OL.

As shown in FIG. 22, the camera 1 is a so-called mirrorless camera with interchangeable lenses equipped with an optical system OL as a photographing lens 2.
In the camera 1, the light from an object (subject) (not shown) is focused by the photographing lens 2 and is placed on the image pickup surface of the image pickup unit 3 via an OLPF (Optical low pass filter) (not shown). Form a subject image. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the image pickup unit 3, and the image of the subject is generated. This image is displayed on an EVF (Electronic Viewfinder) 4 provided in the camera 1. This allows the photographer to observe the subject via the EVF4. Further, when the photographer presses the release button (not shown), the image of the subject generated by the image pickup unit 3 is stored in the memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

As can be seen from each of the embodiments described later, the optical system OL provided in the camera 1 as the photographing lens 2 has a large diameter and the aberration is satisfactorily corrected over the entire in-focus region by its characteristic lens configuration. Has a system. Therefore, according to the camera 1, it is possible to realize an optical device having an optical system having a large aperture and satisfactorily corrected aberration over the entire focusing region.

Although an example of a mirrorless camera has been described as the camera 1, the optical device of the present embodiment is not limited to this. For example, even when a single-lens reflex type camera having a quick return mirror in the camera body and observing a subject by a finder optical system has the above-mentioned optical system OL, the same effect as that of the camera 1 can be obtained.

The method for manufacturing an optical system of the present embodiment is configured to include a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole in order from the object side, and the following conditional expression is used. It is a method of manufacturing an optical system configured to satisfy (1) and (2).
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo <2.100 (1)
1.500 <f / Bf <10.000 (2)
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting,
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.

As a result, various aberrations can be satisfactorily corrected from the in-focus state of an infinite object to the in-focus state of a short-range object, and the large diameter suitable for both autofocus and manual focus covers the entire in-focus region. It is possible to manufacture an optical system in which aberrations are well corrected.

Hereinafter, the outline of the manufacturing method of the optical system OL according to the present embodiment will be described with reference to FIG. 23. First, in order from the object side, the optical system is arranged so as to consist of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole (S1). Next, it is arranged so as to satisfy a predetermined conditional expression (S2).

According to the above-mentioned method for manufacturing an optical system, it is possible to manufacture an optical system having a large aperture and well corrected for aberrations over the entire in-focus region.

It should be noted that the conditions and configurations described above are those that exert the above-mentioned effects, and are not limited to those that satisfy all the conditions and configurations, and are any of the conditions or configurations, or any of them. It is possible to obtain the above-mentioned effect even if the combination of the above conditions or configurations is satisfied.

Further, each of the examples described below 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.

For example, each of the examples described below shows a three-group or four-group configuration as a numerical example of an optical system, but the present embodiment is not limited to this, and other group configurations (for example, five groups, etc.) can be used. An optical system can also be configured. Specifically, a lens or a lens group may be added to the most object side or the most image side of the optical system of each of the following examples. Alternatively, a lens or a lens group may be added between adjacent lens groups. In the present specification, the lens group refers to a portion having at least one lens separated by an air interval that changes at the time of focusing, but is composed of at least one or more lenses separated by an air interval. If it is, it may be a lens group.

The in-focus lens group can also be applied to autofocus, and is also suitable for driving a motor for autofocus (for example, an ultrasonic motor, a stepping motor, a VCM motor, etc.).

In addition, the lens group or partial lens group is moved so as to have a displacement component in the direction orthogonal to the optical axis, or is rotationally moved (swinged) in the in-plane direction including the optical axis to cause image blur caused by camera shake or the like. It may be a group of anti-vibration lenses to be corrected.

Further, the lens surface may be formed of a spherical surface or a flat surface, or may be formed of an aspherical surface. When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment can be prevented, which is preferable. Further, even if the image plane is displaced, the deterioration of the depiction performance is small, 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 surface of glass into an aspherical shape. Any aspherical surface may be used. 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.

The aperture diaphragm S is preferably arranged inside or outside the lens group, but the role may be substituted by the frame of the lens without providing the member as the aperture diaphragm.

Further, in order to reduce flare and ghost and achieve high optical performance with high contrast, each lens surface may be provided with an antireflection film having high transmittance in a wide wavelength range.

With the above configuration, it is possible to provide a bright optical system OL and a photographing apparatus having this optical system OL, which have good optical performance.

Hereinafter, each embodiment according to this embodiment will be described with reference to the drawings. Tables 1 to 7 are shown below, and these are tables of specifications in the first to seventh embodiments.

The cross-sectional view of the optical system shown in FIG. 1 is a cross-sectional view of the optical system of the first embodiment. The focusing state of the distance object is described, and the movement locus of each lens group at the time of focusing is shown between the two.
Each lens in FIG. 1 is shown as L11, L12, L13, ... In order from the object side (left side of the paper surface).
Further, in FIG. 1, the focusing lens group is shown as F (F1, F2) together with the movement locus at the time of focusing.
Further, FIGS. 2 and 3 are aberration diagrams of the point at infinity (FIG. 2) and the short-distance focusing (FIG. 3) of the first embodiment, and the aberrations are well corrected. Recognize. However, FNo indicates an F number, Y indicates an image height, and d and g indicate aberration curves of the d-line and g-line, respectively. In astigmatism, the solid line indicates the sagittal image plane and the dotted line indicates the meridional image plane.

Note that each reference numeral with respect to FIG. 1 according to the first embodiment is used independently for each embodiment in order to avoid complication of explanation due to an increase in the number of digits of the reference numeral. Therefore, even if they have a reference reference numeral common to the drawings according to the other embodiments, they do not necessarily have the same configuration as the other embodiments.

In each embodiment, C line (wavelength 656.3 nm), d line (wavelength 587.6 nm), F line (wavelength 486.1 nm), and g line (wavelength 435.8 nm) are selected as the calculation targets of the aberration characteristics.

In the (basic specifications) in the table, f is the focal length of the entire optical system OL, FNo is the F number, ω is the half angle (maximum incident angle unit: °), Y is the image height, and TL is the total lens length (TL). The distance from the front surface of the lens to the final surface of the lens on the optical axis plus BF), and BF is the back focal length (actually through a filter from the final surface of the lens to the near-axis image plane on the optical axis). Distance) and BF (air equivalent length) indicate back focus (distance converted by air from the final surface of the lens on the optical axis to the near-axis image plane).

In the (plane data) in the table, the plane number is the order of the optical planes from the object side along the traveling direction of the light beam, r is the radius of refraction of each optical plane, and d is the next optical plane (or the next optical plane) from each optical plane. The plane spacing, which is the distance on the optical axis to the image plane), nd indicates the refractive index of the material of the optical member with respect to the d-line, and νd indicates the Abbe number based on the d-line of the material of the optical member. (Object surface) is an object surface, (variable) is a variable surface spacing, "∞" of curvature radius is a plane or an aperture, (aperture) is an aperture diaphragm S, an image plane is an image plane I, and BF is a back focus ( The distance from the final surface of the lens on the optical axis to the paraxial image plane) is shown. BF includes the case where it is variable even if it is not shown as (variable). The refractive index of air "1.00000" is omitted.

In the (aspherical surface data) in the table, the aspherical surface has a height in the direction perpendicular to the optical axis as y, and is along the optical axis from the tangent plane of the apex of each aspherical surface to each aspherical surface at the height y. The distance (sag amount) is S (y), the radius of curvature (near axis radius of curvature) of the reference sphere is r, the conical constant is κ, and the nth order (n = 4,6,8,10,12,14, When the aspherical coefficient of 16) is An, it is expressed by the following equation (a). In the following examples, " ^en " indicates "× 10 -n". For example, "-4.54914e-06" indicates "-4.54914 × ^10-6 ".

S (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 ＋ A12 × y ¹² ＋ A14 × y ¹⁴ ＋ A16 × y ¹⁶ (a)

In each embodiment, the second-order aspherical coefficient A2 is 0. Further, in the table of each embodiment, the aspherical surface is marked with * on the right side of the surface number.

In the table (lens group focal length), the start surface indicates the surface number on the most object side of each group, the end surface indicates the surface number on the image side of each group, and the group focal length indicates the focal length of each group. ..

In the (variable interval data) in the table, each variable interval di at infinity (infinity focusing state) and close (short distance focusing state) is shown. Here, di indicates a variable interval between the i-th plane and the (i + 1) th plane. Note that d0 indicates the distance on the optical axis from the object to the apex of the lens surface on the object side.

Hereinafter, in all the specification values, "mm" is generally used for the focal length f, the radius of curvature r, the surface 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. Further, the unit is not limited to "mm", and other appropriate units can be used.

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

(First Example)
FIG. 1 is a cross-sectional view of an optical system according to the first embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

In the front group A, in order from the object side, a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a positive lens L12 having a meniscus lens shape with a convex surface facing the object side, and a meniscus lens shape having a concave surface facing the object side. Negative lens L13, a positive lens L14 with a meniscus lens shape with a concave surface facing the object side, a biconvex positive lens L15, a positive lens L16 with a meniscus lens shape with a convex surface facing the object side, and a meniscus lens with a convex surface facing the object side. It is composed of a junction negative lens in which a positive lens L17 having a shape, a biconvex positive lens L18, and a biconcave negative lens L19 are joined.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side and a plano-convex positive lens L22 with a convex surface facing the object side, and the F2 group consists of a biconvex positive lens L31 and a biconvex positive lens L32. The R group is composed of a positive lens L41 having a meniscus lens shape with a convex surface facing the object side, a junction negative lens in which a biconvex positive lens L42 and a biconcave negative lens L43 are joined, and a biconcave negative lens L44. There is.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

In this optical system, the image side surface of the negative lens L11 (curvature radius r1) and the object side surface of the negative lens L13 (curvature radius r2) are configured to face each other.

In this optical system, focusing from infinity to a close object point is configured by moving the F1 group and the F2 group toward the object side along the optical axis.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 1 shows an optical system and an image plane I of the optical system.
Table 1 below shows the values of each specification in the first embodiment.

(Table 1) First Example (Basic Specifications)
f 51.29
FNo 1.23
ω 22.8
Y 21.60
TL 163.307
BF 13.112
BF (air equivalent length) 12.567

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 280.68270 2.650 1.64000 60.1
2 46.02198 3.540 r1
3 50.87481 4.190 1.94595 18.0
4 62.23366 16.510
5 -43.98849 3.200 1.55298 55.1 r2
6 -158.30791 4.050
7 -82.01412 6.700 1.59349 67.0
8-52.72274 -3.000
9 0.00000 3.100
10 113.04472 10.810 1.59349 67.0
11 -113.04472 0.200
12 75.49059 6.540 1.59349 67.0
13 275.33026 0.200
14 48.85546 10.350 1.59349 67.0
15 571.46325 0.680
16 290.13527 6.040 1.59319 67.9
17 -109.11000 2.160 1.73800 32.3
18 40.04126 7.790
19 (Aperture) ∞ (Variable)
20 -37.07012 1.700 1.72047 34.7
21 -95.03209 0.200
22 58.85968 6.200 1.59319 67.9
23 0.00000 (variable)
24 391.60810 6.460 1.59306 67.0
25 * -165.00000 2.600
26 * 71.00000 4.000 1.76450 49.1
27 -430.72555 (variable)
28 137.78125 3.100 1.61800 63.3
29 795.36428 0.100
30 87.92389 5.700 1.90265 35.8
31 -127.68000 1.800 1.61266 44.5
32 40.89766 7.760
33 * -64.58764 1.800 1.51680 64.0
34 423.87378 10.810
35 0.00000 1.600 1.51680 63.9
36 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
25 1.52295e + 01 -2.31391e-05 7.84797e-08 -2.22440e-10 4.85260e-13
A12 A14 A16
-7.08430e-16 6.01460e-19 -2.27720e-22
Surface κ A4 A6 A8 A10
26 -1.15900e-01 -2.10400e-05 5.52111e-08 -1.44760e-10 2.04610e-13
A12 A14 A16
1.63620e-16 -1.08770e-18 1.17040e-21
Surface κ A4 A6 A8 A10
33 9.47940e + 00 9.45827e-07 1.06743e-08 -3.94910e-11 1.67840e-13
A12 A14 A16
-4.43900e-16 6.53730e-19 0.00000e + 00

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 18 114.58
F1 20 23 -707.60
F2 24 27 57.73
R 28 34 -157.33

(Variable interval data)
Close to infinity
d0 ∞ 467.50
Magnification --- 0.1000
f 51.29-
d19 19.164 11.437
d23 2.000 3.584
d27 1.900 8.043
d36 0.702 0.701

2 and 3 are aberration diagrams of the optical system according to the first embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(Second Example)
FIG. 4 is a cross-sectional view of the optical system according to the second embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

In the front group A, in order from the object side, a biconvex positive lens L11, a biconcave negative lens L12, a meniscus lens-shaped negative lens L13 with a concave surface facing the object side, and a meniscus lens-shaped positive lens with a concave surface facing the object side. It is composed of L14, a biconvex positive lens L15, a biconvex positive lens L16, a positive lens L17 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L18, and a junction negative lens L19 joined together. ing.
The rear group B is composed of the F1 group and the R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side, a positive lens L22 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L23, and a biconvex positive lens L24. The R group is composed of a junction negative lens in which a biconvex positive lens L31 and a biconcave negative lens L32 are joined, a meniscus lens-shaped positive lens L33 with a convex surface facing the object side, and a biconvex negative lens L34.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

In this optical system, the image side surface of the negative lens L12 (curvature radius r1) and the object side surface of the negative lens L13 (curvature radius r2) are configured to face each other.

In this optical system, focusing from infinity to a close object point is configured by moving the F1 group toward the object side along the optical axis.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 4 shows an optical system and an image plane I of the optical system.
Table 2 below shows the values of each specification in the second embodiment.

(Table 2) Second Example (Basic Specifications)
f 51.60
FNo 1.23
ω 23.2
Y 21.60
TL 159.001
BF 13.301
BF (air equivalent length) 12.756

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 561.29662 3.472 1.94595 18.0
2 -305.56196 2.894 1.00000
3 -98.58907 2.400 1.64000 60.2
4 59.18522 16.590 1.00000 r1
5 -38.57810 2.000 1.61266 44.5 r2
6 -77.71819 1.125 1.00000
7 -66.43595 7.639 1.48749 70.3
8 -40.96684 -5.500
9 0.00000 5.600
10 208.08414 8.046 1.59349 67.0
11 -131.00411 0.200
12 66.25297 12.563 1.59349 67.0
13 -226.94593 0.200
14 47.98878 10.340 1.59349 67.0
15 602.32269 0.100
16 227.35510 6.148 1.49782 82.6
17 -119.73996 2.100 1.73800 32.3
18 38.44017 8.050
19 (Aperture) ∞ (Variable)
20 -38.72427 1.700 1.67300 38.1
21 -200.60706 0.200
22 46.90854 6.300 1.59349 67.0
23 281.98159 2.937
24 10173.51700 5.973 1.59349 67.0
25 -60.25114 1.938
26 * 125.33569 4.027 1.74389 49.5
27 -171.03743 (variable)
28 103.50665 4.719 1.92286 20.9
29 -306.58773 1.800 1.66111 32.7
30 36.00000 2.023
31 52.72529 5.109 1.84850 43.8
32 442.08579 3.792
33 * -74.13130 1.800 1.88202 37.2
34 182.21660 10.710
35 0.00000 1.600 1.51680 64.1
36 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
26 -4.41960e + 01 -1.67080e-06 -5.36140e-09 -1.35087e-13 0.00000e + 00
33 1.08477e + 01 4.00275e-06 8.47101e-09 -1.45201e-11 3.36098e-14

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 18 96.06
F1 20 27 56.72
R 28 34 -102.22

(Variable interval data)
Close to infinity
d0 ∞ 468.42
Magnification --- 0.1000
f 51.60-
d19 17.715 12.059
d27 1.700 7.357
d36 0.991 0.991

5 and 6 are aberration diagrams of the optical system according to the second embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(Third Example)
FIG. 7 is a cross-sectional view of the optical system according to the third embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

The front group A is a bonded negative lens in which a positive lens L11 having a meniscus lens shape with a convex surface facing the object side and a negative lens L12 having a meniscus lens shape having a convex surface facing the object side are joined in order from the object side. Negative lens L13 in the shape of a meniscus lens with a concave surface, positive lens L14 in the shape of a meniscus lens with a concave surface facing the object side, biconvex positive lens L15, biconvex positive lens L16, biconvex positive lens L17, concave surface on the object side It is composed of a junction negative lens in which a positive lens L18 having a meniscus lens shape and a biconcave negative lens L19 are joined.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side and a positive lens L22 having a meniscus lens shape with a convex surface facing the object side, and the F2 group is a biconvex positive lens L31 and biconvex positive. It is composed of a lens L32, and the R group is composed of a junction negative lens in which a biconvex positive lens L41 and a biconcave negative lens L42 are joined, a meniscus lens-shaped positive lens L43 with a convex surface facing the object side, and a biconcave negative lens L44. Has been done.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 7 shows an optical system and an image plane I of the optical system.
Table 3 below shows the values of each specification in the third embodiment.

(Table 3) Third Example (Basic Specifications)
f 50.44
FNo 1.23
ω 23.6
Y 21.60
TL 161.001
BF 11.501
BF (air equivalent length) 10.956

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 71.68293 3.506 1.94595 18.0
2 98.68966 2.400 1.51680 63.9
3 * 34.17342 23.790 r1
4-36.23950 2.000 1.58144 41.0 r2
5 -109.48322 3.227
6 -54.61894 8.468 1.59349 67.0
7 -39.57217 0.200
8 152.50213 6.564 1.59349 67.0
9 -235.07193 0.200
10 101.07244 6.599 1.59349 67.0
11 -2010.92240 0.200
12 64.86498 11.625 1.59349 67.0
13 -128.09154 0.200
14 -9456.76000 8.595 1.59349 67.0
15 -50.42595 2.100 1.67300 38.1
16 52.95853 6.325
17 (Aperture) ∞ (Variable)
18 -39.28674 1.700 1.73800 32.3
19 -83.98274 0.200
20 43.45027 6.300 1.59349 67.0
21 88.65078 (variable)
22 189.04968 6.862 1.59349 67.0
23 -64.92428 1.131
24 145.44614 3.138 1.74320 49.3
25 * -320.04070 (variable)
26 72.64919 5.823 1.92286 20.9
27 -228.15986 1.800 1.73012 28.7
28 34.16027 2.269
29 51.49364 4.937 1.75500 52.3
30 482.77881 4.157
31 -63.36088 1.800 1.88202 37.2
32 * 149.98309 8.898
33 0.00000 1.600 1.51680 64.1
34 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
3 1.32680e + 00 -1.10898e-06 1.31476e-12 -4.13742e-12 5.96666e-15
A12
-5.43510e-18
Surface κ A4 A6 A8 A10
25 1.00000e + 00 4.73166e-06 5.64935e-10 4.85981e-12 0.00000e + 00
32 1.00000e + 00 -2.51953e-06 2.05941e-09 -7.81003e-12 9.64611e-15

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 16 99.25
F1 18 21 -381.48
F2 22 25 51.77
R 26 32 -81.32

(Variable interval data)
Close to infinity
d0 ∞ 452.37
Magnification --- 0.1000
f 50.44-
d17 18.108 10.946
d21 3.575 5.079
d25 1.700 7.358
d34 1.002 1.002

8 and 9 are aberration diagrams of the optical system according to the third embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(Fourth Example)
FIG. 10 is a cross-sectional view of the optical system according to the fourth embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

In the front group A, in order from the object side, a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a positive lens L12 having a meniscus lens shape with a convex surface facing the object side, and a meniscus lens shape having a convex surface facing the object side. Negative positive lens L13 joined with the negative lens L13, negative lens L14 with a meniscus lens shape with a concave surface facing the object side, biconvex positive lens L15, positive lens L16 with a meniscus lens shape with a concave surface facing the object side, biconvex It is composed of a junction negative lens in which a positive lens L17, a biconvex positive lens L18, a biconvex positive lens L19, and a biconcave negative lens L110 are joined.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side and a biconvex positive lens L22, the F2 group is composed of a biconvex positive lens L31 and a biconvex positive lens L32, and the R group is composed of a biconvex positive lens L32. Consists of a positive lens L41 with a meniscus lens shape with a convex surface facing the object side, a bonded negative lens L42 with a biconvex positive lens L42 and a biconcave negative lens L43 bonded together, and a negative lens L44 with a meniscus lens shape with the concave surface facing the object side. Has been done.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

In this optical system, the image side surface of the negative lens L13 (curvature radius r1) and the object side surface of the negative lens L14 (curvature radius r2) are configured to face each other.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 10 shows an optical system and an image plane I of the optical system.
Table 4 below shows the values of each specification in the fourth embodiment.

(Table 4) Fourth Example (Basic Specifications)
f 35.25
FNo 1.24
ω 32.2
Y 21.60
TL 165.000
BF 11.500
BF (air equivalent length) 10.955

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 89.32754 2.500 1.64000 60.2
2 * 28.41029 7.398
3 50.53314 5.851 2.00100 29.1
4 130.33728 2.500 1.55298 55.1
5 35.48671 23.791 r1
6 -34.72160 2.192 1.55298 55.1 r2
7 -3763.19840 0.200
8 161.94880 6.456 1.59349 67.0
9 -102.83340 0.200
10 -524.15678 8.697 1.59349 67.0
11 -50.23150 0.200
12 96.65872 5.534 1.59349 67.0
13 -862.05167 0.200
14 123.28920 6.007 1.59349 67.0
15 -177.55812 0.200
16 268.09904 10.649 1.59319 67.9
17 -40.38897 2.000 1.67300 38.1
18 91.36172 4.426
19 (Aperture) ∞ (Variable)
20 -37.46768 1.700 1.73800 32.3
21 -123.38467 0.200
22 70.54203 5.800 1.72916 54.6
23 -511.93789 (variable)
24 102.38447 5.700 1.59349 67.0
25 * -170.75720 5.061
26 * 80.00000 3.800 1.76450 49.1
27 -532.36896 (variable)
28 91.55721 3.834 1.49782 82.6
29 4513.25730 0.200
30 201.76955 4.942 1.95375 32.3
31 -172.46641 1.800 1.67300 38.1
32 48.75165 7.616
33 * -58.06622 1.800 1.69680 55.5
34 -196.84782 9.495
35 0.00000 1.600 1.51680 64.1
36 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
2 8.63700e-01 -4.94390e-07 -2.25643e-10 -7.45212e-13 7.07578e-17
25 1.00000e + 00 -8.53553e-06 1.43475e-08 -1.72696e-11 1.07404e-14
26 1.00000e + 00 -1.11143e-05 6.17280e-09 -6.48775e-12 3.59508e-15
A12
-7.05540e-19
Surface κ A4 A6 A8 A10
33 1.00000e + 00 -2.42337e-06 3.58561e-09 -9.77205e-12 -1.08954e-16

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 18 79.30
F1 20 23 -638.37
F2 24 27 51.55
R 28 34 -104.22

(Variable interval data)
Close to infinity
d0 ∞ 312.47
Magnification --- 0.1000
f 35.25-
d19 18.347 13.608
d23 2.000 3.137
d27 1.700 5.302
d36 0.405 0.405

11 and 12 are aberration diagrams of the optical system according to the fourth embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(Fifth Example)
FIG. 13 is a cross-sectional view of the optical system according to the fifth embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

In the front group A, in order from the object side, a meniscus lens-shaped negative lens L11 having a convex surface facing the object side, a meniscus lens-shaped negative lens L12 having a convex surface facing the object side, and a meniscus lens shape having a convex surface facing the object side. Positive lens L13, biconcave negative lens L14, biconvex positive lens L15, biconvex positive lens L16, biconvex positive lens L17, meniscus lens-shaped positive lens L18 with the convex surface facing the object side, concave surface facing the object side. It is composed of a bonded negative lens in which a positive lens L19 having a meniscus lens shape and a negative lens L110 having a meniscus lens shape having a concave surface facing the object side are joined.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a biconcave negative lens L21 and a biconvex positive lens L22, and the F2 group is composed of a meniscus lens-shaped positive lens L31 and a biconvex positive lens L32 with the concave surface facing the object side. A junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42, a junction positive lens of a biconvex positive lens L43 and a meniscus-shaped negative lens L44 with a concave surface facing the object side, and a concave surface facing the object side. It is composed of a negative lens L45 having a meniscus shape.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

In this optical system, the image side surface of the negative lens L12 (curvature radius r1) and the object side surface of the negative lens L14 (curvature radius r2) are configured to face each other.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 13 shows an optical system and an image plane I of the optical system.
Table 5 below shows the values of each specification in the fifth embodiment.

(Table 5) Fifth Example (Basic Specifications)
f 28.50
FNo 1.24
ω 37.9
Y 21.60
TL 159.999
BF 11.500
BF (air equivalent length) 10.955

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 65.78093 2.000 1.69350 53.2
2 * 27.00000 9.514
3 67.76189 1.800 1.64000 60.2
4 * 30.14132 3.460 r1
5 48.58319 6.886 1.95375 32.3
6 77.93204 14.630
7 -46.97277 4.500 1.64000 60.2 r2
8 131.32283 0.200
9 73.03981 5.770 1.59349 67.0
10 -764.03804 0.200
11 186.54312 5.669 1.59349 67.0
12 -103.74187 0.200
13 305.69367 6.649 1.59349 67.0
14 -72.25597 0.200
15 58.71790 6.277 1.59349 67.0
16 492.46988 5.239
17 -98.51249 8.806 1.49782 82.6
18 -30.18896 2.000 1.61266 44.5
19 -74.16167 1.000
20 (aperture) ∞ (variable)
21 -41.26732 1.700 1.73800 32.3
22 106.03276 0.200
23 48.10480 6.600 1.59319 67.9
24-114.20927 (variable)
25 -111.30737 2.540 1.61800 63.3
26 * -68.67812 0.200
27 * 54.38044 7.460 1.76450 49.1
28 -71.60470 (variable)
29 188.53706 4.267 1.59319 67.9
30 -88.72672 1.800 1.49632 65.3
31 26.75005 4.410
32 83.87176 11.560 1.59319 67.9
33 -21.21314 1.800 1.73800 32.3
34 -59.57903 2.294
35 * -30.40171 1.800 1.51680 63.9
36 -214.62417 8.910
37 0.00000 1.600 1.51680 64.1
38 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
2 9.23900e-01 -4.69891e-07 -4.17120e-10 1.11934e-12 0.00000e + 00
4 1.21690e + 00 -3.22251e-06 -8.85798e-10 -1.97209e-11 3.09127e-14
A12
-3.63100e-17
Surface κ A4 A6 A8 A10
26 1.00000e + 00 3.89724e-06 8.93172e-10 -2.68215e-12 0.00000e + 00
27 1.00000e + 00 -3.97515e-06 -1.96473e-09 -1.42330e-13 -1.18545e-15
35 1.00000e + 00 1.06340e-05 -7.88050e-09 3.97129e-11 -7.99650e-14

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 19 53.78
F1 21 24 -147.49
F2 25 28 36.15
R 29 36 -60.41

(Variable interval data)
Close to infinity
d0 ∞ 250.62
Magnification --- 0.1000
f 28.50-
d20 13.170 10.648
d24 2.000 2.530
d28 1.700 3.693
d38 0.990 0.990

14 and 15 are aberration diagrams of the optical system according to the fifth embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(6th Example)
FIG. 16 is a cross-sectional view of the optical system according to the sixth embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

In the front group A, in order from the object side, a meniscus lens-shaped positive lens L11 with a concave surface facing the object side, a biconcave negative lens L12, a meniscus lens-shaped positive lens L13 with a concave surface facing the object side, and a biconvex positive lens. L14, a positive lens L15 having a meniscus lens shape with a concave surface facing the object side, a positive lens L16 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L17, and a bonded negative lens L18 joined together. It is composed of.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side and a positive lens L22 having a meniscus lens shape with a convex surface facing the object side. It is composed of a positive lens L32 having a meniscus lens shape with a convex surface, and the R group is a junction negative lens and a biconvex positive lens in which a positive lens L41 with a meniscus lens shape with a concave surface facing the object side and a biconcave negative lens L42 are joined. It is composed of L43 and both concave and negative lenses L44.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 16 shows an optical system and an image plane I of the optical system.
Table 6 below shows the values of each specification in the sixth embodiment.

(Table 6) Example 6 (basic specifications)
f 51.60
FNo 1.45
ω 23.3
Y 21.60
TL 131.000
BF 13.300
BF (air equivalent length) 12.755

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 -586.32842 2.233 1.94594 18.0
2 -221.27208 3.240
3 -63.73911 2.400 1.64000 60.2
4 70.98553 11.146 r1
5 -41.12359 5.395 1.61266 44.5 r2
6 -42.99781 0.100
7 75.79513 8.408 1.59349 67.0
8-136.07944 0.200
9 -643.66310 4.487 1.59349 67.0
10 -104.67250 0.200
11 40.44605 5.624 1.59349 67.0
12 70.92793 0.100
13 56.02814 7.018 1.49782 82.6
14 -488.58889 2.100 1.73800 32.3
15 50.90651 5.843
16 (Aperture) ∞ (Variable)
17 -39.72234 1.700 1.72047 34.7
18 -184.92774 0.848
19 42.53567 6.300 1.49782 82.6
20 12882.71200 (variable)
21 56.76493 7.298 1.59349 67.0
22 -108.34629 6.120
23 * 96.31448 2.307 1.74389 49.5
24 2613.31880 (variable)
25 -867.21714 2.257 1.92286 20.9
26 -182.38116 1.800 1.49693 65.0
27 36.00000 2.538
28 77.38378 4.268 1.84850 43.8
29 -256.69283 3.362
30 * -46.44164 1.800 1.88202 37.2
31 215.48087 10.710
32 0.00000 1.600 1.51680 64.1
33 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
23 -4.62518e + 01 -2.54555e-06 -1.93441e-08 6.72994e-12 0.00000e + 00
30 4.67220e + 00 6.88347e-06 1.14794e-08 8.86183e-12 2.57043e-14

(Focal length of lens group)
Lens group Start surface End surface Group focal length A 1 15 92.67
F1 17 20 -463.40
F2 21 24 45.35
R 25 31 -46.36

(Variable interval data)
Close to infinity
d0 ∞ 481.34
Magnification --- 0.1000
f 51.60-
d16 14.841 9.189
d20 2.000 4.035
d24 1.768 5.385
d33 0.990 0.990

17 and 18 are aberration diagrams of the optical system according to the sixth embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

(7th Example)
FIG. 19 is a cross-sectional view of the optical system according to the seventh embodiment.
The optical system according to this embodiment is composed of a front group A having a positive refractive power and a rear group B having a positive refractive power in order from the object side.

The front group A is a junction in which a positive lens L11 having a meniscus lens shape with a concave surface facing the object side, a biconcave negative lens L12, and a positive lens L13 having a meniscus lens shape with a convex surface facing the object side are joined in this order from the object side. Negative lens, negative lens L14 with a meniscus lens shape with a concave surface facing the object side, positive lens L15 with a meniscus lens shape with a concave surface facing the object side, biconvex positive lens L16, meniscus lens shape with a convex surface facing the object side It is composed of a positive lens L17, a positive lens L18 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L19, and a junction negative lens L110 in which a biconcave negative lens L110 is joined.
The rear group B is composed of an F1, F2 group, and an R group. Here, the F1 group is composed of a negative lens L21 having a meniscus lens shape with a concave surface facing the object side and a positive lens L22 having a meniscus lens shape with a convex surface facing the object side, and the F2 group is a meniscus lens with a concave surface facing the object side. It is composed of a positive lens L31 with a shape and a plano-convex positive lens L32 with a convex surface facing the object side. It is composed of a positive lens L43 having a lens shape and a biconcave negative lens L44.
Further, the aperture stop S is arranged between the front group A and the rear group B.
A filter group FL composed of a low-pass filter or the like is arranged between the rear group B and the image plane I. An image pickup device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

An image is formed on the image plane I by this optical system and an image is taken. FIG. 19 shows an optical system and an image plane I of the optical system.
Table 7 below shows the values of each specification in the seventh embodiment.

(Table 7) Example 7 (basic specifications)
f 82.02
FNo 1.24
ω 14.5
Y 21.60
TL 160.006
BF 13.701
BF (air equivalent length) 13.156

(Surface data)
Surface number r d nd νd Equation (7) (8) (15)
0 (paraboloid) ∞ (variable)
1 -500.00000 4.141 1.48749 70.3
2 -166.66667 0.256
3 -163.81862 1.800 1.55298 55.1
4 96.33720 6.033 1.66382 27.4 r1
5 294.61628 10.782
6 -75.93264 2.817 1.55298 55.1 r2
7 -188.73960 0.200
8-3574.99840 6.456 1.48749 70.3
9 -134.49391 0.100
10 78.03293 12.533 1.59349 67.0
11 -1459.12130 0.200
12 95.48816 7.486 1.59349 67.0
13 404.44858 0.200
14 46.79755 7.911 1.59349 67.0
15 80.84962 0.100
16 67.21392 11.041 1.49782 82.6
17 -301.98614 2.100 1.73800 32.3
18 31.29759 10.093
19 (Aperture) ∞ (Variable)
20 -38.43782 1.700 1.72047 34.7
21 -79.55106 0.200
22 43.92412 6.300 1.59319 67.9
23 182.13428 (Variable)
24 -68.26751 3.852 1.59349 67.0
25 * -41.08941 0.200
26 * 86.68157 4.441 1.74389 49.5
27 0.00000 (variable)
28 194.89958 5.109 1.90265 35.7
29 -105.41890 1.800 1.55298 55.1
30 36.00000 0.754
31 42.38265 5.253 1.77250 49.6
32 190.18266 3.340
33 * -121.88623 1.800 1.64000 60.2
34 59.06896 11.105
35 0.00000 1.600 1.51680 64.1
36 0.00000 BF
Image plane ∞

(Aspherical data)
Surface κ A4 A6 A8 A10
25 2.25800e-01 -2.63453e-07 7.00870e-10 0.00000e + 00 0.00000e + 00
26 1.24355e + 01 -4.91263e-06 -3.20212e-09 1.07263e-12 -1.15021e-14
33 3.30744e + 01 1.56233e-06 8.02732e-09 -3.37791e-11 5.78485e-14

(Focal length of lens group)
Lens group Start surface End surface Focal length A 1 18 150.69
F1 20 23 1007.16
F2 24 27 67.54
R 28 34 -125.50

(Variable interval data)
Close to infinity
d0 ∞ 753.14
Magnification --- 0.1000
df 82.02-
d19 17.945 8.586
d23 7.663 7.383
d27 1.698 11.338
d36 0.996 1.000

20 and 21 are aberration diagrams of the optical system according to the seventh embodiment at infinity focusing and short-distance focusing, respectively, and various aberrations are satisfactorily corrected to provide excellent imaging performance. You can see that it has.

According to each of the above embodiments, various aberrations can be satisfactorily corrected from the in-focus state of an infinite object to the in-focus state of a short-range object, and a large-diameter optical system suitable for both autofocus and manual focus. Can be realized.

Next, the table of [Conditional expression correspondence value] is shown below. In this table, the values corresponding to each conditional expression (1) to (17) are collectively shown for all the examples (1st to 7th examples).
Conditional expression
(1) 0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) ／ h (s)) × FNo ＜ 2.100
(2) 1.500 <f / Bf <10.000
(3) 0.600 <fA / (2 × f) <1.500
(4) 0.500 <(fFR x FNo ² ) /f<2.900
(5) 0.500 <βF / βB <2.000
(6) 0.600 <θgFLn + 0.0021 × νdLn <0.660
(7) 0.500 <-r1 / r2 <2.000
(8) 0.500 <(r1-r2) /f<5.000
(9) -0.500 <fF2 / fF1 <0.500
(10) -0.300 <βF2 / βF1 <1.200
(11) 0.750 <(| 1 / fAF | + | 1 / fAR |) x fA <7.000
(12) -0.060 <-NdL-0.011 x νdL + 2.12 <0.034
(13) 24.7 <νdL <58.0
(14) 0.400 <fA / fB <2.500
(15) -0.500 <(r1 + r2) / (r1-r2) <0.500
(16) -0.500 <fF2 / fF1 <0.500
(17) -0.300 <βF2 / βF1 <1.200

[Conditional expression correspondence value]
Conditional expression 1st Example 2nd Example 3rd Example 4th Example 5th Example
(1) 1.187 1.085 1.084 1.360 1.604
(2) 4.143 4.045 4.604 3.218 2.602
(3) 1.117 0.931 0.984 1.125 0.944
(4) 1.798 1.679 1.759 2.319 2.236
(5) 0.998 0.935 0.944 0.928 0.759
(6) 0.658 (17) 0.657 (5) 0.655 (15) 0.655 (17) 0.657 (18)
0.657 (20) 0.658 (17) 0.658 (18) 0.658 (20) 0.657 (21)
0.657 (31) 0.655 (20) 0.655 (31) 0.655 (31) 0.657 (33)
0.655 (33)
(7) 1.046 1.534 0.943 1.022 0.642
(8) 1.755 1.895 1.396 1.992 2.706
(9) -0.082 -0.162 -0.136 -0.081 -0.245
(10) 0.327 0.292 0.312 0.287 0.082
(11) 4.595 2.943 3.904 5.181 4.317
(12) -0.039 (5) 0.018 (5) 0.027 (15) -0.039 (4) 0.018 (18)
0.027 (17) 0.027 (17) 0.027 (18) -0.039 (6) 0.027 (21)
0.018 (20) 0.027 (20) -0.027 (27) 0.027 (17)
0.018 (31) 0.027 (20)
(13) 55.1 (5) 44.5 (5) 38.1 (15) 55.1 (4) 44.5 (18)
32.3 (17) 32.3 (17) 32.3 (18) 55.1 (6) 32.3 (21)
34.7 (20) 38.1 (20) 28.7 (27) 38.1 (17)
44.5 (31) 32.3 (20)
(14) 1.570 1.112 1.024 1.061 0.621
(15) 0.023 0.211 -0.029 0.011 -0.218
(16) -0.082 -0.162 -0.136 -0.081 -0.245
(17) 0.327 0.292 0.312 0.287 0.082

Conditional expression 6th embodiment 7th embodiment
(1) 1.076 1.227
(2) 4.046 6.233
(3) 0.898 0.919
(4) 1.934 1.188
(5) 0.758 0.970
(6) 0.657 (5) 0.658 (17)
0.658 (14) 0.657 (20)
0.657 (17)
0.655 (30)
(7) 1.726 1.269
(8) 2.173 2.101
(9) -0.098 0.067
(10) 0.273 0.598
(11) 1.090 0.958
(12) 0.018 (5) 0.027 (3)
0.027 (14) 0.027 (6)
0.018 (17) 0.027 (17)
0.018 (20)
-0.039 (29)
(13) 44.5 (5) 55.1 (3)
32.3 (14) 55.1 (6)
34.7 (17) 32.3 (17)
34.7 (20)
55.1 (29)
(14) 0.636 1.659
(15) 0.266 0.118
(16) -0.098 0.067
(17) 0.273 0.598
However, in the above (6), (12) and (13), the numbers in parentheses after the numerical values are the numbers of the surfaces corresponding to the numerical values.

OL optics A Front group B Rear group S Aperture aperture I Image plane FL Filter group F Focusing group (F1, F2)
Fixed group in the posterior group

Claims

An optical system consisting of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole in order from the object side, and satisfying the following conditional expression.
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo ＜ 2.100
1.500 <f / Bf <10.000
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting,
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.
The optical system according to claim 1, which satisfies the following conditional expression.
0.600 <fA / (2 × f) <1.500
However,
fA: Focal length of the front group during infinite shooting.
The optical system according to claim 1 or 2, wherein the front group is fixed at the time of focusing, the rear group is at least one focusing group moving on an optical axis, and the following conditional expression is satisfied.
0.500 <(fF × FNo 2 ) / f <2.900
However,
fF: The combined focal length of the entire in-focus group during infinite shooting.
The optical system according to any one of claims 1 to 3, wherein the front group is fixed at the time of focusing, the rear group is at least one focusing group moving on the optical axis, and the following conditional expression is satisfied. ..
0.500 <βF / βB <2,000
However,
βF: Magnification of the in-focus group during infinite shooting,
βB: Magnification of the rear group during infinite shooting.
The optical system according to any one of claims 1 to 4, which has at least one negative lens satisfying the following conditional expression.
0.600 <θgFLn + 0.0021 × νdLn <0.660
However,
νdLn: Abbe number for the d line of the negative lens,
θgFLn: Partial dispersion ratio of the g-line and F-line of the negative lens.
The optical system according to any one of claims 1 to 5, wherein the front group includes a configuration in which three or more positive lenses are arranged in succession.
There are two or more negative lenses between the lens on the most object side and the fourth lens in order from the object side of the front group, and the curvature of the image side of the negative lens on the object side among the concave surfaces facing each other. The optical system according to any one of claims 1 to 6, wherein the radius is r1 and the radius of curvature of the side surface of the object of the negative lens on the image side is r2, which satisfies the following conditional expression.
0.500 <-r1 / r2 <2,000
The optical system according to claim 7, which satisfies the following conditional expression.
0.500 <(r1-r2) /f <5.000
The optical system according to any one of claims 1 to 8, wherein the front group is fixed at the time of focusing, and the rear group has a plurality of groups moving on the optical axis.
The front group is fixed at the time of focusing, and the rear group includes F1 group and F2 group which are two focusing groups moving on the optical axis, and any one of claims 1 to 9 satisfying the following conditional expression. The optical system according to item 1.
-0.500 <fF2 / fF1 <0.500
However,
fF2: Focal length of the F2 group,
fF1: Focal length of the F1 group.
Upon focusing, the front group is fixed, and the rear group is two focusing groups that move on the optical axis, the F1 group and the F2 group, and any one of claims 1 to 10 that satisfies the following conditional expression. The optical system described in the section.
-0.300 <βF2 / βF1 <1.200
However,
βF2: Horizontal magnification of the F2 group,
βF1: Horizontal magnification of the F1 group.
The optical system according to any one of claims 1 to 11, wherein the rear group includes a lens having at least one aspherical surface.
From the object side, it consists of a front group with a positive refractive power, an aperture, and a rear group with a positive refractive power as a whole. An optical system that satisfies the following conditional expression, with the lens group up to the lens placed closest to the object side as the AF group and the lens group placed on the image side of the AF group as the AR group.
0.750 <(| 1 / fAF | + | 1 / fAR |) x fA <7,000
However,
fAF: Focal length of AF group during infinite shooting,
fAR: Focal length during infinite shooting of AR group,
fA: Focal length of the front group during infinite shooting.
The optical system according to claim 13, further comprising at least one negative lens satisfying the following conditional expression.
-0.060 <-NdL-0.011 x νdL + 2.12 <0.034
24.7 <νdL <58.0
However,
νdL: Abbe number for the d line of the negative lens,
NdL: Partial dispersion ratio of the g-line and F-line of the negative lens.
The optical system according to claim 13 or 14, which satisfies the following conditional expression.
0.400 <fA / fB <2.5500
However,
fB: Focal length of the rear group during infinite shooting.
There are two or more negative lenses between the lens on the most object side and the fourth lens in order from the object side of the front group, and the curvature of the image side of the negative lens on the object side among the concave surfaces facing each other. The optical system according to any one of claims 13 to 15, where the radius is r1 and the radius of curvature of the side surface of the object of the negative lens on the image side is r2, which satisfies the following conditional expression.
-0.500 <(r1 + r2) / (r1-r2) <0.500
The front group is fixed at the time of focusing, the rear group includes the F1 group and the F2 group which are two focusing groups moving on the optical axis, and the subsequent group which is fixed at the time of focusing, and the following conditional expression is used. The optical system according to any one of claims 13 to 16, which is satisfied.
-0.500 <fF2 / fF1 <0.500
However,
fF2: Focal length of the F2 group,
fF1: Focal length of the F1 group.
The front group is fixed at the time of focusing, and the rear group includes two focusing groups, F1 group and F2 group, which move on the optical axis, and any of claims 13 to 17 satisfying the following conditional expression. The optical system according to item 1.
-0.300 <βF2 / βF1 <1.200
However,
βF2: Horizontal magnification of the F2 group,
βF1: Horizontal magnification of the F1 group.
An optical device having the optical system according to any one of claims 1 to 18.
Manufacture of an optical system composed of a front group having a positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole in order from the object side, so as to satisfy the following conditional expression. Method.
0.600 <((h (max) －h (1)) / h (1) ＋ (h (max) －h (s)) / h (s)) × FNo ＜ 2.100
1.500 <f / Bf <10.000
However,
h (max): The height at which the marginal ray is the highest in the front group,
h (1): Marginal ray height on the front surface,
h (s): Marginal ray height at the aperture surface,
FNo: Open F value during infinite shooting,
f: Focal length of the whole system at the time of infinite shooting,
Bf: Air equivalent length from the final surface of the lens on the optical axis to the paraxial image plane during infinite shooting.