WO2017134928A1

WO2017134928A1 - Teleconverter lens and optical apparatus

Info

Publication number: WO2017134928A1
Application number: PCT/JP2016/086673
Authority: WO
Inventors: 永華陳; 直己宮川
Original assignee: ソニー株式会社
Priority date: 2016-02-01
Filing date: 2016-12-09
Publication date: 2017-08-10
Also published as: CN109073868A; JP6750638B2; JPWO2017134928A1

Abstract

A teleconverter lens of the disclosure of the present invention has, overall, a negative refractive power, and comprises the following, in order from the object side to the image side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; and a third lens group having a positive refractive power. The first lens group and the third lens group each include a positive lens and are formed of no more than two lenses. The teleconverter lens is detachably attached to a master lens on the image side thereof, and thereby enlarge the focal length of the master lens.

Description

Teleconverter lens and optical device

The present disclosure relates to a teleconverter lens mounted on the image plane side with respect to a master lens to expand a focal length of the master lens, and an optical apparatus provided with such a teleconverter lens.

The focal length of the master lens can be expanded by inserting a rear conversion lens (teleconverter lens) having a negative focal length between the master lens and the camera body. The teleconverter lens has a function of a relay, and re-forms the primary image of the master lens incident on the teleconverter lens on the imaging device of the camera body. Therefore, in the case of mounting the teleconverter lens, it is premised that the flange back of the master lens is longer than the on-axis distance from the front lens of the teleconverter lens to the primary image formation of the master lens.

JP-A-5-142473 JP, 2013-250291, A JP 2013-235217 A

The long flange back of the conventional single-lens reflex camera system weakens the power of the teleconverter lens and can gently extend the light incident on the teleconverter lens. On the other hand, in recent years, a large number of imaging lenses having a short flange back and reduced in size have been developed, for example, for mirrorless camera systems. For this reason, the conventional teleconverter lens for a camera system with a long flange back is not suitable for a recent mirrorless camera system.

Patent Documents 1 to 3 disclose teleconverter lenses applicable to single-lens reflex camera systems. The teleconverter lens described in Patent Document 1 has a configuration in which incident light rays are gradually extended, and its application is difficult except for a master lens with a long exit pupil or a camera system with a long flange back.

Although the teleconverter lens described in Patent Document 2 has a positive, negative, positive three-group configuration in order from the object side, since the object side principal point is located near the center of the teleconverter lens, the mirror When applied to a less camera, the front lens of the teleconverter lens interferes with the master lens.

The teleconverter lens described in Patent Document 3 has a configuration in which the power of the lens unit on the image plane side is weak, and when applied to a full-frame camera system, the curvature of field at the outermost periphery becomes large, resulting in a small size. And it is difficult to obtain high optical performance.

The teleconverter lens enlarges the focal length of the master lens and at the same time the aberration is also enlarged according to the magnification. For example, in the case of a teleconverter lens having a magnification of 2 times, the lateral aberration of the master lens is enlarged by 2 times and the longitudinal aberration is expanded by 4 times when mounted on the master lens. The combined aberration of the state in which the teleconverter lens is mounted on the master lens is the aberration of the master lens expanded and the aberration of the teleconverter lens added thereto. In order to make the teleconverter lens versatile, it is preferable to bring the aberration of the teleconverter lens close to no aberration.

Therefore, for example, maintaining excellent imaging performance even when using a telephoto objective lens with an F-number of about 2 to 2.8 and an enlargement magnification of about 1.4 to 2 times the focal length as the master lens It is desirable to develop a teleconverter lens that can In addition, development of a teleconverter lens that can be used for a mirrorless camera and has small size and good optical performance is desired.

It is desirable to provide a teleconverter lens that achieves miniaturization and high imaging performance, and an optical device that is detachably mounted with such a teleconverter lens.

A first teleconverter lens according to an embodiment of the present disclosure has a first lens group having a negative refractive power as a whole and having a positive refractive power in order from an object side to an image surface side, The second lens group having a negative refractive power and the third lens group having a positive refractive power, and the first lens group and the third lens group each include two or less lenses including a positive lens. The focal length of the master lens is expanded by being detachably mounted on the image plane side with respect to the master lens, by satisfying the following conditional expression.
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group.

A first optical device according to an embodiment of the present disclosure includes a master lens, an imaging element that outputs an imaging signal according to an optical image formed by the master lens, and a detachable lens between the master lens and the imaging element. And a teleconverter lens configured by the first teleconverter lens according to the embodiment of the present disclosure.

A second teleconverter lens system according to an embodiment of the present disclosure has a first lens group having a negative refractive power as a whole and having a positive refractive power in order from the object side to the image side. The second lens group having a negative refractive power and the third lens group having a positive refractive power, and the first lens group and the third lens group each include two or less lenses including a positive lens. The focal length of the master lens is expanded by being detachably mounted on the image plane side with respect to the master lens, by satisfying the following conditional expression.
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: magnification of teleconverter lens Lr: distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane f2: focal length of the second lens group.

A second optical device according to an embodiment of the present disclosure includes a master lens, an imaging element that outputs an imaging signal according to an optical image formed by the master lens, and a detachable lens between the master lens and the imaging element. And a teleconverter lens configured by the second teleconverter lens according to the embodiment of the present disclosure.

A third teleconverter lens system according to an embodiment of the present disclosure has a first lens group having a negative refractive power as a whole and having a positive refractive power in order from an object side to an image surface side; The second lens group having a negative refractive power and the third lens group having a positive refractive power, and the first lens group and the third lens group each include two or less lenses including a positive lens. The focal length of the master lens is expanded by being detachably mounted on the image plane side with respect to the master lens, by satisfying the following conditional expression.
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: The distance from the object-side principal point of the teleconverter lens to the lens surface of the teleconverter lens closest to the object (however, the time when the lens surface on the most object side is closer to the object than the object-side principal point is negative) )
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.

A third optical device according to an embodiment of the present disclosure includes a master lens, an imaging element that outputs an imaging signal according to an optical image formed by the master lens, and a detachable lens between the master lens and the imaging element. And a teleconverter lens configured by the third teleconverter lens according to the embodiment of the present disclosure.

In the first to third teleconverter lenses or optical apparatuses according to one embodiment of the present disclosure, the teleconverter lens is detachably mounted on the image plane side with respect to the master lens, thereby making the focus of the master lens Increase the distance.

According to the first to third teleconverter lenses or optical devices according to the embodiment of the present disclosure, the teleconverter lenses as a whole are configured in three groups, and the configuration of each lens group is optimized. , Miniaturization and high imaging performance can be realized.

In addition, the effect described here is not necessarily limited, and may be any effect described in the present disclosure.

FIG. 2 is a lens cross-sectional view at the time of infinity focusing on an example of the configuration of a master lens to which the teleconverter lens according to an embodiment of the present disclosure is attached. It is a lens sectional view showing the 1st example of composition of the teleconverter lens concerning one embodiment of this indication. It is lens sectional drawing which shows the 2nd structural example of a teleconverter lens. It is lens sectional drawing which shows the 3rd structural example of a teleconverter lens. It is lens sectional drawing which shows the 4th structural example of a teleconverter lens. It is lens sectional drawing which shows the 5th structural example of a teleconverter lens. It is lens sectional drawing which shows the 6th structural example of a teleconverter lens. It is lens sectional drawing which shows the 7th structural example of a teleconverter lens. FIG. 2 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end of the master lens shown in FIG. 1 at infinity focusing. 3 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end when focusing on infinity, in the configuration example (numerical example 1) in which the teleconverter lens shown in FIG. 2 is attached to the master lens shown in FIG. is there. 3 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end when focusing at infinity according to the configuration example (numerical example 2) in which the teleconverter lens shown in FIG. 3 is attached to the master lens shown in FIG. is there. 6 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end when focusing on infinity, in the configuration example (numerical example 3) in which the teleconverter lens shown in FIG. 4 is attached to the master lens shown in FIG. is there. 6 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end when focusing on infinity, in the configuration example (numerical example 4) in which the teleconverter lens shown in FIG. 5 is attached to the master lens shown in FIG. is there. 6 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end in infinity focusing in the configuration example (numerical example 5) in which the teleconverter lens shown in FIG. 6 is attached to the master lens shown in FIG. is there. 8 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end in infinity focusing in the configuration example (numerical example 6) in which the tele conversion lens shown in FIG. 7 is attached to the master lens shown in FIG. is there. 8 is an aberration diagram showing various aberrations at the wide-angle end and at the telephoto end when focusing on infinity, in the configuration example (numerical example 7) in which the teleconverter lens shown in FIG. 8 is attached to the master lens shown in FIG. is there. It is a block diagram which shows the outline of the imaging device which mounted the teleconverter lens between the master lens and the camera main body. It is a lens sectional view showing an example of composition which attached a teleconverter lens to a master lens. It is a block diagram showing an example of 1 composition of a control system of an imaging device as an optical instrument.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order.
1. Basic configuration of lens Action / Effect 3. Application example to optical instrument 4. Numerical embodiment of lens 5. Other embodiments

<1. Basic configuration of lens>
FIG. 1 shows a configuration example of a master lens ML to which a teleconverter lens TCL according to an embodiment of the present disclosure is attached. In FIG. 1, Z1 denotes an optical axis, and IMG denotes an image plane. For example, as shown in FIG. 18, the teleconverter lens TCL according to the present embodiment enlarges the focal length of the master lens ML by being detachably mounted on the image surface side with respect to the master lens ML. It is.

FIG. 2 shows a first configuration example of the teleconverter lens TCL according to an embodiment of the present disclosure. FIG. 3 shows a second configuration example of the teleconverter lens TCL. FIG. 4 shows a third configuration example of the teleconverter lens TCL. FIG. 5 shows a fourth configuration example of the teleconverter lens TCL. FIG. 6 shows a fifth configuration example of the teleconverter lens TCL. FIG. 7 shows a sixth configuration example of the teleconverter lens TCL. FIG. 8 shows a seventh configuration example of the teleconverter lens TCL. Numerical examples in which specific numerical values are applied to these configuration examples will be described later.

Hereinafter, the configuration of the teleconverter lens TCL according to the present embodiment will be described as needed in association with the configuration example shown in FIG. 2 and the like, but the technology according to the present disclosure is not limited to the configuration example illustrated. .

The teleconverter lens TCL according to the present embodiment includes, in order from the object side to the image surface side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a positive lens group G2. And a third lens group G3 having a refractive power of

The first lens group G1 and the third lens group G3 are each composed of two or less lenses including a positive lens.

It is desirable that the teleconverter lens TCL according to the present embodiment at least satisfy conditional expression (1), conditional expression (3), or conditional expression (4) described later.

Besides, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy a predetermined conditional expression etc. described later.

<2. Action / Effect>
Next, the operation and effects of the teleconverter lens TCL according to the present embodiment will be described. In addition, a desirable configuration of the teleconverter lens TCL according to the present embodiment will be described.
In addition, the effect described in this specification is an illustration to the last, is not limited, and may have other effects.

According to the teleconverter lens TCL according to the present embodiment, the configuration is made into three groups as a whole, and optimization of the configuration of each lens group is achieved, so that downsizing and high imaging performance can be realized. The teleconverter lens TCL according to the present embodiment can realize, for example, about 1.4 to 2 times as the magnification ratio of the focal length. In addition, when the telephoto objective lens having an F number of about 2 to 2.8 is used as the master lens ML, excellent imaging performance can be maintained. In addition, the teleconverter lens TCL according to the present embodiment can be used for a mirrorless camera or the like.

In the teleconverter lens TCL according to the present embodiment, the third lens group G3 is configured to include a single positive lens component, and includes a positive lens having a convex surface on the image plane side closest to the image plane side. Is desirable. Here, one positive lens component may have a configuration of only one positive lens, or may be a positive cemented lens including a negative lens and a positive lens from the object side. In particular, when the third lens group G3 has a configuration of only one positive lens, the correction of distortion can be well controlled. Further, in the configuration in which the positive lens having a convex surface directed to the image surface side is disposed on the most image surface side of the third lens group G3, the angle of the light ray from the final lens surface of the teleconverter lens TCL becomes large. While being able to shorten the exit pupil distance, it becomes possible to maintain excellent imaging performance.

Further, in the teleconverter lens TCL according to the present embodiment, the first lens group G1 may be configured of a single positive lens. Further, the first lens group G1 may be configured of one negative lens and one positive lens from the object side. In particular, in the case where it is desired to weaken the power of the entire system of the teleconverter lens TCL, it is effective to correct various aberrations by constructing the first lens group G1 by a combination of a negative lens and a positive lens.

It is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (1).
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group G3 Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group G3.

Conditional expression (1) represents the shape of the positive lens included in the third lens group G3. If the upper limit value of the conditional expression (1) is exceeded, inward coma aberration is likely to occur in the light flux above the chief ray. In addition, it is difficult to make a balance with distortion. Conversely, when the lower limit value of the conditional expression (1) is not reached, an outgoing coma aberration is likely to be generated in the light flux on the upper side of the chief ray, and it becomes difficult to maintain good peripheral performance.

In order to better realize the effect of the conditional expression (1) described above, it is more preferable to set the numerical range of the conditional expression (1) as in the following conditional expression (1) ′.
-1.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.3 (1) '

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (2).
2.2 <f3 / (-f2) <7.2 (2)
However,
f2: focal length of second lens group G2 f3: focal length of third lens group G3.

The teleconverter lens TCL according to the present embodiment divides the lens configuration between the positive lens of the first lens group G1 and the positive lens component of the third lens group G3, and as a whole, from the object side, positive and negative , Is a positive three-group configuration. Furthermore, the negative power of the second lens group G2 is appropriately increased, and the positive power of the third lens group G3 is appropriately increased. By arranging in this manner, it is possible to bring the principal point position on the object side closer to the object side. This makes it possible to increase the number of lenses disposed in the narrow space between the master lens ML and the camera body while securing the magnification of the teleconverter lens TCL, which is advantageous for aberration correction. If the upper limit value of the conditional expression (2) is exceeded, the power of the third lens group G3 becomes weak, and the correction effect of the curvature of field in the tangential direction becomes small. Conversely, if the lower limit value of the conditional expression (2) is not reached, the power of the second lens group G2 becomes weak, and it becomes difficult to correct the curvature of field in the sagittal direction.

In order to realize the effect of the above-mentioned conditional expression (2) better, it is more preferable to set the numerical range of the conditional expression (2) to the following conditional expression (2) ′.
2.4 <f3 / (-f2) <6.5 (2) '

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (3).
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: Magnification of teleconverter lens TCL Lr: Distance on the optical axis from the lens surface of the teleconverter lens TCL closest to the object side to the lens surface closest to the image plane f2: Focal length of the second lens group G2.

Condition (3) defines the relationship between the power of the second lens group G2 and the total length when the magnification β of the teleconverter lens TCL is constant. If the lower limit value of the conditional expression (3) is not reached, the negative refractive power of the second lens group G2 becomes too weak, and it becomes difficult to secure the magnification. Conversely, if the upper limit value of the conditional expression (3) is exceeded, the negative refractive power of the second lens group G2 becomes too strong, and as a result, the total length becomes too short. In addition, the Petzval sum of the teleconverter lens TCL becomes too large, which makes aberration correction difficult.

In order to better realize the effect of the conditional expression (3), it is more desirable to set the numerical range of the conditional expression (3) as in the following conditional expression (3) ′.
0.1 <−f2 / (Lr * β) <0.4 (3) ′

Further, in the teleconverter lens TCL according to the present embodiment, it is desirable that the second lens group G2 includes at least one cemented lens. In this case, it is preferable that at least one cemented lens includes a triple cemented lens including a negative lens, a positive lens, and a negative lens in order from the object side to the image surface side. This configuration is advantageous for correction of the sagittal image plane and the tangential image plane. In addition, the influence of the eccentricity can be reduced and the assembly becomes easy.

On the other hand, in particular, when the magnification is about 1.4, the cemented lens of the second lens group G2 is a double cemented lens consisting of a negative lens and a positive lens from the object side, or a positive lens from the object side You may comprise by 2-piece cemented lens which consists of negative lenses. In this case, the relative decentering sensitivity between the respective lenses can be suppressed by the configuration in which the two lenses are cemented to each other.

Further, in the teleconverter lens TCL according to the present embodiment, it is desirable that the object-side surface of the cemented lens in the second lens group G2 be aspheric. With this configuration, on-axis and off-axis performance can be significantly improved. In particular, curvature of field can be corrected well. The positive lens in the cemented lens of the second lens group G2 preferably has a biconvex shape. This configuration makes it possible to correct spherical aberration well.

In order to increase the magnification of the teleconverter lens TCL, it is more preferable to use two cemented lenses in the second lens group G2. In particular, it is more preferable to use two cemented lenses of a cemented doublet and a cemented triplet. By using two cemented lenses, decentration sensitivity can be reduced while astigmatism is well corrected, and assembly becomes easy.

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (4).
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: The distance from the object-side principal point of the teleconverter lens TCL to the lens surface of the tele-converter lens TCL closest to the object (provided that the lens surface closest to the object is closer to the object than the object-side principal point) Be negative)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens TCL to the lens surface closest to the image plane.

Conditional expression (4) defines the position of the object-side principal point of the teleconverter lens TCL. In order to prevent interference with the master lens ML when supporting the short flange back master lens ML, the teleconverter lens TCL is disposed at a relatively large distance from the lens surface on the most image plane side of the master lens ML. Need to Therefore, it is preferable to dispose the object-side principal point of the teleconverter lens TCL closer to the object side. If the upper limit value of conditional expression (4) is exceeded, the object-side principal point of the teleconverter lens TCL will be located near the center of the teleconverter lens TCL, making it difficult to cope with the short flange back master lens ML. Become. In particular, when the magnification of the teleconverter lens TCL is lowered to about 1.4 times, the lens arrangement space becomes insufficient, and aberration correction becomes difficult.

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (5).
0.3 <BF / h <1.9 (5)
However,
BF: Back focus in a state in which the tele conversion lens TCL is mounted on the master lens ML h: Maximum image height in a state in which the tele conversion lens TCL is mounted on the master lens ML

The teleconverter lens TCL of the present disclosure is preferably applied to a camera system defined by conditional expression (5). In particular, it is preferable to use it for a mirrorless camera system. By satisfying the conditional expression (5), the configuration when attached to the master lens ML becomes more compact.

Further, it is preferable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (6).
(BF-et_i) / (BF + Lr)> 0.7 (6)
However,
BF: Back focus in a state where the tele conversion lens TCL is mounted on the master lens ML et_i: Distance from the lens surface of the tele conversion lens TCL closest to the image plane to the image side principal point of the tele conversion lens TCL (tele conversion lens TCL When the image-side principal point of the lens is located on the object side with respect to the lens surface closest to the image plane of the teleconverter lens TCL,
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens TCL to the lens surface closest to the image plane.

Conditional expression (6) is a conditional expression for well maintaining the on-axis and off-axis optical performance when corresponding to the short flange back master lens ML. If the lower limit value of the conditional expression (6) is not reached, the angle of a ray emitted from the lens surface on the most image plane side of the teleconverter lens TCL becomes large, and the off-axis performance becomes worse.

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (7).
0.03 <d12 / (-f) <0.2 (7)
However, d12: distance on the optical axis between the first lens group G1 and the second lens group G2 f: focal length of the entire system of the teleconverter lens TCL.

Since the teleconverter lens TCL has negative power, positive spherical aberration is large. By setting a relatively large air gap between the first lens group G1 and the second lens group G2, light rays can be converged gently, which is advantageous for correction of spherical aberration. When the value goes below the lower limit value of the conditional expression (7), the distance between the first lens group G1 and the second lens group G2 decreases, and the refractive power of the lens surface closest to the object in the first lens group G1 increases. Too much correction of spherical aberration is excessive. If the upper limit value of conditional expression (7) is exceeded, the distance between the first lens group G1 and the second lens group G2 becomes long, and the refracting power of the lens surface closest to the image plane in the first lens group G1 The refracting power of the lens surface closest to the object side in the second lens group G2 becomes weak, and the correction of various aberrations becomes insufficient.

In order to better realize the effect of the conditional expression (7) described above, it is more desirable to set the numerical range of the conditional expression (7) as in the following conditional expression (7) ′.
0.035 <d12 / (-f) <0.15 (7) '

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (8).
0.3 <| f1 / f | <1.5 (8)
However,
f1: Focal length of the first lens group G1 f: Focal length of the whole system of the teleconverter lens TCL.

Conditional expression (8) defines the relationship between the power of the first lens group G1 and the power of the entire system of the teleconverter lens TCL, and is a conditional expression for correcting the spherical aberration and the curvature of field in a well-balanced manner. If the lower limit value of the conditional expression (8) is not reached, the power of the first lens group G1 becomes too strong, and the correction of spherical aberration becomes excessive. If the upper limit value of the conditional expression (8) is exceeded, the power of the first lens group G1 becomes too weak, the correction of spherical aberration becomes insufficient, and the balance of aberration correction at the center and the periphery becomes worse.

In order to better realize the effect of the conditional expression (8) described above, it is more desirable to set the numerical range of the conditional expression (8) as in the following conditional expression (8) ′.
0.45 <| f1 / f | <1.3 (8) '

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (9).
0.05 <f2 / f <0.4 (9)
However,
f2: Focal length of the second lens group G2 f: Focal length of the entire system of the teleconverter lens TCL.

The conditional expression (9) is a ratio of the power of the second lens group G2 to the power of the entire system of the teleconverter lens TCL, and defines an appropriate power distribution of the second lens group G2. If the lower limit value of the conditional expression (9) is not reached, the power of the second lens group G2 becomes too strong, and correction of astigmatism becomes difficult. If the upper limit value of the conditional expression (9) is exceeded, the power of the second lens group G2 becomes too weak, and in particular, try to realize a teleconverter lens TCL of relatively high magnification with respect to the master lens ML having a short flange back. And it becomes difficult to maintain the magnification.

In order to better realize the effect of the conditional expression (9) described above, it is more desirable to set the numerical range of the conditional expression (9) to the following conditional expression (9) ′.
0.08 <f2 / f <0.4 (9) '

In the teleconverter lens TCL according to the present embodiment, it is desirable that the second lens group G2 includes at least one negative lens. In this case, it is desirable that the teleconverter lens TCL satisfy the following conditional expression (10).
Nd_G2m> 1.85 (10)
However,
Nd_G2m: The highest value of the refractive index of the d-line of at least one negative lens included in the second lens group G2.

It is preferable to bond a positive lens to either the object-side lens surface of the negative lens that satisfies the conditional expression (10) or the lens surface on the image plane side. In that case, it is preferable that the difference ΔNd_G2pm of the refractive index of the d-line between the negative lens and the positive lens satisfies the following condition.
ΔNd_G2pm> 0.25

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (11).
Nd_G3p <1.65 (11)
However,
Nd_G3p: A refractive index of d-line of a positive lens included in the third lens group G3.

Both conditional expressions (10) and (11) are preferable conditional expressions for satisfactorily correcting the Petzval sum. If the ranges of the conditional expressions (10) and (11) are exceeded, the Petzval sum of the entire system of the teleconverter lens TCL becomes large, and it becomes difficult to obtain good imaging performance.

In order to realize the effects of the conditional expressions (10) and (11) more favorably, the numerical ranges of the conditional expressions (10) and (11) are set to the following conditional expressions (10) ′ and (11) ′ It is more desirable to set as follows.
Nd_G2m> 1.90 (10) '
Nd_G3p <1.60 ... (11) '

Further, it is desirable that the teleconverter lens TCL according to the present embodiment satisfy the following conditional expression (12).
15 <νd_G1 <35 (12)
However,
dd_G1: Abbe's number of a positive lens included in the first lens group G1.

νd_G1 is the Abbe number at the d-line. In general, the Abbe number dd at the d-line is nd the refractive index for the d-line (wavelength 587.6 nm), nF the refractive index for the F-line (wavelength 486.1 nm), and the refractive index for the C-line (wavelength 656.3 nm) Assuming nC, it is defined as follows.
d d = (nd-1) / (nF-nC)

Conditional expression (12) is a preferable conditional expression for satisfactorily correcting the chromatic aberration. If the upper limit value of the conditional expression (12) is exceeded, the dispersion of the positive lens included in the first lens group G1 becomes too small, and the cancellation effect with the chromatic aberration generated in the second lens group G2 of negative refractive power is weak Become. The positive lens included in the first lens group G1 has a role of correcting spherical aberration, and the refractive index becomes high. If the lower limit value of the conditional expression (12) is exceeded, the cost is increased, and an appropriate glass material is limited particularly when using an aspheric surface.

Moreover, it is preferable that the teleconverter lens TCL which concerns on this Embodiment has an aspherical surface. The use of an aspheric surface makes the correction of spherical aberration and curvature of field better. When making the lens surface aspheric, any of aspheric aspheric surfaces by grinding, a glass mold aspheric surface with a glass formed into an aspheric surface shape, and a composite aspheric surface with a resin formed into aspheric surface shape on the glass surface It may be a spherical surface.

<3. Example of application to optical equipment>
An application example of the teleconverter lens TCL according to the present embodiment to an optical device will be described. Below, an example of composition of an imaging device is explained as an example of an optical instrument.

FIG. 17 shows an outline of the imaging device 100 in which the teleconverter lens TCL is mounted between the master lens ML and the camera body 101. FIG. 19 illustrates a block configuration example of a control system of the imaging device 100.

The imaging device 100 is, for example, a digital still camera, and includes an imaging optical system 11 and a camera body 101 as shown in FIG. An imaging element 12 is disposed in the camera body 101. A subject image obtained through the imaging optical system 11 forms an image on the imaging surface of the imaging device 12. The maximum image height on the imaging plane is h.

As the photographing optical system 11, the master lens ML shown in FIG. 1 and the teleconverter lens TCL of each configuration example shown in FIGS. 2 to 8 can be applied. FIG. 18 shows a configuration example in which the teleconverter lens TCL shown in FIG. 2 is mounted on the image plane side of the master lens ML shown in FIG. By applying the photographing optical system 11 including the teleconverter lens TCL of the present disclosure to a general interchangeable lens etc. optical apparatus, high optical performance and miniaturization can be achieved even in a state where the focal distance of the master lens ML is expanded. Can be realized.

As illustrated in FIG. 19, the imaging device 100 includes a camera block 10, a camera signal processing unit 20, an image processing unit 30, an LCD (Liquid Crystal Display) 40, and an R / W (reader / writer) 50. , A central processing unit (CPU) 60, an input unit 70, and a lens drive control unit 80.

The camera block 10 bears an imaging function, and includes an optical system including a photographing optical system 11 and an imaging element 12 such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging element 12 is configured to output an imaging signal (image signal) corresponding to the optical image by converting the optical image formed by the imaging optical system 11 into an electrical signal.

The camera signal processing unit 20 performs various signal processing such as analog-to-digital conversion, noise removal, image quality correction, conversion to luminance and color difference signals, and the like on the image signal output from the imaging device 12.

The image processing unit 30 performs recording / reproduction processing of an image signal, and performs compression encoding / expansion decoding processing of an image signal based on a predetermined image data format, conversion processing of data specifications such as resolution, etc. It has become.

The LCD 40 has a function of displaying various data such as an operation state of the user on the input unit 70 and a photographed image. The R / W 50 writes the image data encoded by the image processing unit 30 to the memory card 1000 and reads the image data recorded on the memory card 1000. The memory card 1000 is, for example, a semiconductor memory that can be attached to and detached from a slot connected to the R / W 50.

The CPU 60 functions as a control processing unit that controls each circuit block provided in the imaging device 100, and controls each circuit block based on an instruction input signal or the like from the input unit 70. The input unit 70 includes various switches and the like for which a user performs a required operation. The input unit 70 includes, for example, a shutter release button for performing a shutter operation, a selection switch for selecting an operation mode, and the like, and outputs an instruction input signal according to the operation by the user to the CPU 60. ing. The lens drive control unit 80 controls the drive of the lens disposed in the camera block 10, and controls a motor (not shown) that drives each lens of the photographing optical system 11 based on a control signal from the CPU 60. It has become.

Although not shown, the image pickup apparatus 100 includes a shake detection unit that detects shake of the apparatus accompanying camera shake.

The operation of the imaging device 100 will be described below.
In the photographing standby state, under control of the CPU 60, an image signal photographed in the camera block 10 is output to the LCD 40 via the camera signal processing unit 20 and displayed as a camera through image. Further, for example, when an instruction input signal for zooming or focusing is input from the input unit 70, the CPU 60 outputs a control signal to the lens drive control unit 80, and the photographing optical system is controlled based on the control of the lens drive control unit 80. Eleven predetermined lenses move.

When the shutter (not shown) of the camera block 10 is operated by an instruction input signal from the input unit 70, the photographed image signal is output from the camera signal processing unit 20 to the image processing unit 30, and compression encoding processing is performed. Converted to digital data in data format. The converted data is output to the R / W 50 and written to the memory card 1000.

Note that focusing is performed, for example, when the shutter release button of the input unit 70 is half-pressed or fully-pressed for recording (shooting), etc., based on the control signal from the CPU 60. It is performed by moving a predetermined lens of the photographing optical system 11.

When reproducing image data recorded in the memory card 1000, predetermined image data is read from the memory card 1000 by the R / W 50 in response to an operation on the input unit 70, and the image processing unit 30 decompresses and decodes the image data. After the processing, the reproduced image signal is output to the LCD 40 and the reproduced image is displayed.

Further, the CPU 60 operates the lens drive control unit 80 based on a signal output from a shake detection unit (not shown) to move the anti-vibration lens group in a direction substantially perpendicular to the optical axis Z1 according to the shake amount.

In the above embodiment, an example is shown in which the optical device is applied to an imaging device such as a digital still camera, but the application range of the optical device is not limited to the digital still camera, and various other optical Applicable to equipment. For example, the present invention can be applied to digital single-lens reflex cameras, digital non-reflex cameras, digital video cameras, surveillance cameras, and the like. In addition, the present invention can be widely applied as a camera unit of a digital input / output device such as a mobile phone in which a camera is incorporated or an information terminal in which a camera is incorporated. The present invention can also be applied to a lens-interchangeable camera.

<4. Numerical embodiment of lens>
Next, specific numerical examples of the master lens ML and the teleconverter lens TCL according to the present embodiment will be described. Here, numerical examples will be described in which specific numerical values are applied to the master lens ML shown in FIG. 1 and the teleconverter lens TCL of each configuration example shown in FIG. 2 to FIG.

In addition, about the meaning etc. of the symbol shown in each following table or description, it is as showing below. “Plane No.” indicates the number of the ith plane counted from the object side to the image plane side. “Ri” indicates the value (mm) of the paraxial radius of curvature of the i-th surface. “Di” indicates the value (mm) of the distance on the optical axis between the i-th surface and the (i + 1) -th surface. “Ndi” indicates the value of the refractive index at the d-line (wavelength 587.6 nm) of the material of the optical element having the i-th surface. “Νdi” indicates the value of Abbe number at the d-line of the material of the optical element having the i-th surface. The portion where the value of “Ri” is “∞” indicates a flat surface or a stop surface (aperture stop St). The surface marked "*" in "Surface No." indicates that it is an aspheric surface. The surface described as "STO" in "surface No." indicates that it is the aperture stop St. "BF" indicates back focus. "Fno." Indicates an F number, and "ω" indicates a half angle of view.

In each numerical embodiment, the aspheric shape is defined by the following aspheric equation. In the data indicating the aspheric coefficient described later, a power of 10 is represented using E. For example, “1.2 × 10 ⁻⁰² ” is represented as “1.2 E-02”.

(Expression of aspheric surface)
x = c ² y ² / [1+ {1- (1 + K) c ² y ² } ^1/2 ] + ΣAi · y ⁱ

here,
x: distance in the optical axis direction from the lens surface vertex y: height in the direction perpendicular to the optical axis c: paraxial curvature at the lens vertex (reciprocal of paraxial radius of curvature)
K: Conic constant Ai: Ith aspheric coefficient.

[Numerical Example of Master Lens ML]
Table 1 shows basic lens data of a numerical example in which specific numerical values are applied to the master lens ML shown in FIG. The master lens ML is a zoom lens, and FIG. 1 shows the arrangement of each lens group at the wide-angle end (short focal length end) and the telephoto end (long focal length end). Further, FIG. 1 shows a locus of movement of each lens unit when zooming from the wide-angle end to the telephoto end. During focusing, some of the lens units of the master lens ML move along the optical axis. FIG. 1 also shows the moving directions of some lens groups during focusing.

The master lens ML of this embodiment is a telephoto zoom lens whose focal length changes in a range of about 70 mm to 200 mm and Fno is about 2.8. Although the numerical embodiment of the teleconverter lens TCL described later shows an embodiment in the case of being attached to the master lens ML of the present embodiment, the master lens ML applied to the teleconverter lens TCL of the present embodiment is not limited to this embodiment. It is not limited to the configuration shown in the embodiment.

Table 2 shows the focal length, F number (Fno), angle of view 2ω, and back focus (BF) of the entire lens system at the wide-angle end (short focal length end) and at the telephoto end (long focal length end). , Total length, and image height values. [Table 2] also shows variable surface spacing values. In the master lens ML, the values of the surface intervals D10, D15, D17, D22, D30, and D32 change during zooming.

The master lens ML of the present embodiment includes an aspheric surface. The values of the aspheric coefficients are shown below.
The 26th plane K = 0, A4 = -2.7344E-6, A6 = 1.6153E-10
The 31st surface K = 0, A4 = 1.2894E-006, A6 = -2.3559E-008, A8 = 3.0254E-01,
The thirty-second surface K = 0, A4 = -5.1807E-006, A6 = -3.5426E-008, A8 = -1.4272E-011, A10 = 3.1502E-015
The thirty-sixth surface K = 0, A4 = 3.3738E-006, A6 = 7.9254E-009, A8 =-2.5398E-011, A10 = 3.7458E-014

In the following, the focal length f10 of the tenth lens group G10, the focal length f20 of the 20th lens group G20, the focal length f30 of the 30th lens group G30, and the focal length f40 of the 40th lens group G40, and the 50th lens group G50 And the values of the focal length f60 of the 60th lens group G60.
f10 = 96.9
f20 = -25.4
f30 = 81.4
f40 = 58.5
f50 = -61.2
f60 = 285.5

The master lens ML includes, in order from the object side to the image side along the optical axis Z1, a tenth lens group G10 having a positive refractive power, a twentieth lens group G20 having a negative refractive power, and a positive lens. A 30th lens group G30 having a refractive power, a 40th lens group G40 having a positive refractive power, a 50th lens group G50 having a negative refractive power, and a 60th lens group G60 having a positive refractive power It consists essentially of six lens groups arranged.

The tenth lens group G10 is composed of, in order from the object side to the image plane side, a first F lens group G1F having positive refractive power and a first R lens group G1R having positive refractive power.

The twentieth lens group G20 is composed of, in order from the object side to the image plane side, a second f lens group G2F and a second R lens group G2R.

In the master lens ML of this embodiment, the first F lens group G1F, the 40th lens group G40, and the 60th lens group G60 are fixed in the optical axis direction with respect to the image plane during zooming from the wide angle end to the telephoto end. The twentieth lens group G20, the thirtieth lens group G30, and the fifty lens group G50 move in the optical axis direction.

In the master lens ML of this embodiment, the first R lens group G1R, the 50th lens group G50, and the negative lens on the most image plane side of the 20th lens group G20 form a focusing lens group. The first R lens group G1R moves to the object side along the optical axis at the time of focusing from an infinite distance object to a close distance object. The 50th lens group G50 moves toward the image plane side along the optical axis when focusing from an infinite distance object to a close distance object. The negative lens closest to the image plane in the 20th lens group G20 moves toward the object along the optical axis when focusing from an infinite distance object to a near distance object.

The aperture stop St is disposed between the 30th lens group G30 and the 40th lens group G40.

The first F lens group G1F is composed of, in order from the object side, a negative meniscus lens L1F1, a positive lens L1F2, and a positive meniscus lens L1F3. The first R lens group G1R is composed of, in order from the object side, a negative meniscus lens L1R1 and a positive meniscus lens L1R2.

The 20th lens group G2 is composed of, in order from the object side, a negative lens L21, a cemented lens in which a negative lens L22 and a positive lens L23 are bonded, and a negative meniscus lens L24.

The negative lens L21 and a cemented lens in which the negative lens L22 and the positive lens L23 are cemented together constitute a second F lens group G2F. Further, a negative meniscus lens L24 which is a negative lens closest to the image plane side in the twentieth lens group G20 constitutes a second R lens group G2R. Then, during zooming, the second F lens group G2F and the second R lens group G2R move along different optical paths along the optical axis.

The 30th lens group G3 is composed of, in order from the object side, a positive lens L31, and a cemented lens in which a positive lens L32 and a negative lens L33 are bonded.

The 40th lens group G4 is composed of, in order from the object side, a positive lens L41, a positive lens L42 with an aspheric surface formed on the object side, and a cemented lens in which a negative lens L43 and a positive lens L44 are bonded. ing.

The 50th lens group G50 is composed of, in order from the object side, a negative lens L51 having aspheric surfaces formed on both sides.

The 60th lens group G60, in order from the object side, is a cemented lens in which a positive lens L61 and a negative lens L62 are cemented together, a positive lens L63 having an aspheric surface formed on the object side, a negative lens L64 and a positive lens L65. And a negative lens L66.

In the upper part of FIG. 9, various aberrations at the wide-angle end at the time of infinity focusing in the master lens ML of this embodiment are shown. The lower part of FIG. 9 shows various aberrations of the telephoto end in infinity focusing in the master lens ML of this embodiment. FIG. 9 shows spherical aberration, astigmatism (field curvature), and distortion as various aberrations. In the astigmatism diagram, a solid line (S) indicates a sagittal image plane, and a broken line (M) indicates a value on a meridional image plane. The respective aberration diagrams show values at the d-line. The spherical aberration diagrams also show the values of C-line (wavelength 656.3 nm) and g-line (wavelength 435.8 nm). The same applies to aberration diagrams in the other numerical examples below.

(Configuration common to numerical example of tele converter lens TCL)
Each of the teleconverter lenses TCL to which the following numerical examples are applied has a configuration satisfying the above-described basic configuration of the lens. That is, in each of the teleconverter lenses TCL according to each numerical example, the first lens group G1 having positive refractive power and the second lens group having negative refractive power are sequentially arranged from the object side to the image surface side. It consists of G2 and the 3rd lens group G3 which has positive refractive power.

Further, the following numerical examples of the teleconverter lens TCL show examples where the lens is mounted on the master lens ML shown in the above [Table 1] and [Table 2]. Up to the forty-second surface in the above [Table 1] is a substantial constituent part of the master lens ML. In the following numerical example of the teleconverter lens TCL, the forty-third surface subsequent to the master lens ML is the surface closest to the object side in the teleconverter lens TCL.

Numerical Embodiment 1 of Tele-Converter Lens TCL
Table 3 shows basic lens data of Numerical Example 1 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. [Table 4] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide angle end and the telephoto end in a state of being attached to the master lens ML. And the image height value.

The teleconverter lens TCL according to Numerical Example 1 includes an aspheric surface. The values of the aspheric coefficients are shown below.
The 45th face K = 1.42, A4 = 8. 2362 E-06, A 6 = -3. 13 847 E-08, A 8 = 2.5173 1 E-10, A 10 = -8.

In addition, the magnification β of the teleconverter lens TCL according to Numerical Example 1, the values of focal lengths of the lens units, and the values of the distance between the master lens ML will be described below.
β = 2.0
f1 = 56.48
f2 = -9.86
f3 = 36.68
Distance to master lens ML = 2.6082

In the teleconverter lens TCL according to Numerical Example 1, the first lens group G1 is composed of a biconvex positive lens L1.

The second lens group G2 includes, in order from the object side, a biconcave negative lens L2 having an aspheric surface formed on the object side, a biconvex positive lens L3, and a biconcave negative lens L4. It is composed of a cemented doublet lens composed of a cemented doublet lens, a biconvex positive lens L5, and a negative meniscus lens L6 having a convex surface facing the image surface, and a biconcave negative lens L7. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 is composed of a biconvex positive lens L8.

The upper part of FIG. 10 shows various aberrations at the time of focusing at infinity and in the wide-angle end in Numerical Embodiment 1 with the master lens ML attached. The lower part of FIG. 10 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 1 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 1 is attached to the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 2 of Tele-Converter Lens TCL
Table 5 shows basic lens data of Numerical Embodiment 2 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. [Table 6] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide angle end and the telephoto end in a state of being attached to the master lens ML. And the image height value.

In addition, the magnification β of the teleconverter lens TCL according to Numerical Example 2, the values of focal lengths of the lens units, and the values of the distance between the master lens ML will be described below.
β = 2.0
f1 = 57.45
f2 = -15.35
f3 = 92.28
Distance to master lens ML = 2.6082

In the teleconverter lens TCL according to Numerical Example 2, the first lens group G1 is composed of a biconvex positive lens L1.

The second lens group G2 has a biconcave negative lens L2, a biconvex positive lens L3, and a biconcave negative lens L4 in this order from the object side, and a biconvex positive lens It is configured of a cemented lens consisting of L5 and a negative meniscus lens L6 having a convex surface facing the image plane side. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 includes, in order from the object side, a double cemented lens of a biconcave negative lens L7 and a biconvex positive lens L8.

The upper part of FIG. 11 shows various aberrations at the time of focusing at infinity and in the wide-angle end in Numerical Embodiment 2 with the master lens ML attached. The lower part of FIG. 11 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 2 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 2 is mounted on the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 3 of Tele-Converter Lens TCL
[Table 7] shows basic lens data of Numerical Embodiment 3 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. [Table 8] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide angle end and the telephoto end in a state of being attached to the master lens ML. And the image height value.

The teleconverter lens TCL according to Numerical Example 3 includes an aspheric surface. The values of the aspheric coefficients are shown below.
The forty-fourth surface K = 0.13, A4 = -7.90520E-06, A6 = 3.13613E-10, A8 = 1.60328E-11

Further, the magnification β of the teleconverter lens TCL according to Numerical Example 3, the values of focal lengths of the respective lens units, and the values of the distance between the master lens ML will be described below.
β = 2.0
f1 = 68.22
f2 = -12.55
f3 = 46.46
Distance to master lens ML = 1.6082

In the teleconverter lens TCL according to Numerical Example 3, the first lens group G1 is composed of a biconvex positive lens L1 having an aspheric surface formed on the surface on the image plane side.

The second lens group G2 has a biconcave negative lens L2, a biconvex positive lens L3, and a biconcave negative lens L4 in this order from the object side, and a biconvex positive lens It is composed of a double cemented lens consisting of a negative meniscus lens L6 having a convex surface directed to L5 and the image plane side, and a negative meniscus lens L7 having a convex surface directed to the image plane side.

The third lens group G3 is composed of a biconvex positive lens L8.

The upper part of FIG. 12 shows various aberrations at the time of infinity in-focusing and at the wide-angle end in Numerical Embodiment 3 with the master lens ML attached. The lower part of FIG. 12 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 3 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 3 is mounted on the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 4 of Tele Converter Lens TCL
Table 9 shows basic lens data of Numerical Example 4 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. [Table 10] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide-angle end and the telephoto end in the state of being attached to the master lens ML. And the image height value.

In addition, the magnification β of the teleconverter lens TCL according to Numerical Example 4, the values of focal lengths of the lens units, and the values of the distance between the master lens ML will be described below.
β = 2.0
f1 = 70.46
f2 = -10.06
f3 = 26.95
Distance to master lens ML = 3.6082

In the teleconverter lens TCL according to Numerical Example 4, the first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 having a concave surface facing the image plane side, and a biconvex positive lens L2.

The second lens group G2 includes, in order from the object side, a biconcave negative lens L3, a biconvex positive lens L4, a biconcave negative lens L5, a biconvex positive lens L6, and a biconcave shape And a cemented doublet consisting of a negative lens L7. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 is composed of a biconvex positive lens L8.

The upper part of FIG. 13 shows various aberrations at the time of infinity in-focusing and at the wide-angle end in Numerical Embodiment 4 with the master lens ML attached. The lower part of FIG. 13 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 4 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 4 is attached to the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 5 of Tele-Converter Lens TCL
Table 11 shows basic lens data of Numerical Example 5 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. [Table 12] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide-angle end and the telephoto end in the state of being attached to the master lens ML. And the image height value.

The teleconverter lens TCL according to Numerical Embodiment 5 includes an aspheric surface. The values of the aspheric coefficients are shown below.
The 48th surface K = -1.8400, A4 = -6.1902E-06, A6 = 7.5710E-10, A8 = 1.1492E-11
The 52nd surface K = -0.0954, A4 = 7.2871E-06, A6 = 1.1868E-09, A8 = 3.9430E-12

Further, the magnification β of the teleconverter lens TCL according to Numerical Example 5, the values of focal lengths of the respective lens units, and the values of the distance between the master lens ML will be described below.
β = 1.4
f1 = 57.20
f2 = -14.64
f3 = 37.62
Distance to master lens ML = 2.6082

In the teleconverter lens TCL according to Numerical Example 5, the first lens group G1 is composed of a biconvex positive lens L1.

The second lens group G2 is, in order from the object side, a double cemented lens consisting of a biconcave negative lens L2 and a biconvex positive lens L3, and a biconcave lens in which an aspheric surface is formed on the object side. And a negative lens L4. The aspheric surface of the negative lens L4 is obtained by processing the resin joined to the surface into an aspheric shape. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 is composed of a biconvex lens L5 in which an aspheric surface is formed on the surface on the image plane side.

The upper part of FIG. 14 shows various aberrations at the time of infinity in-focus state and at the wide-angle end in Numerical Embodiment 5 with the master lens ML attached. The lower part of FIG. 14 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 5 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 5 is mounted on the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 6 of Tele Converter Lens TCL
Table 13 shows basic lens data of Numerical Example 6 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. 7. [Table 14] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide-angle end and the telephoto end in the state of being attached to the master lens ML. And the image height value.

The teleconverter lens TCL according to Numerical Example 6 includes an aspheric surface. The values of the aspheric coefficients are shown below.
The 45th surface K = -1.65, A4 = 2.0600E-06, A6 = -2.0120E-09, A8 = 5.1320E-11, A10 = -7.8900E-14

In addition, the magnification β of the teleconverter lens TCL according to Numerical Example 6, the values of focal lengths of the lens units, and the values of the distance between the master lens ML will be described below.
β = 1.4
f1 = 61.46
f2 = -16.99
f3 = 46.35
Distance to master lens ML = 1.6082

In the teleconverter lens TCL according to Numerical Example 6, the first lens group G1 is composed of a positive meniscus lens L1 having a convex surface facing the image plane side.

The second lens group G2 includes, in order from the object side, a biconcave negative lens L2 having an aspheric surface formed on the object side, a biconvex positive lens L3, and a negative meniscus convex on the image surface side It is composed of a double cemented lens consisting of a lens L4 and a biconcave negative lens L5. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 is composed of a biconvex lens L6.

The upper part of FIG. 15 shows various aberrations at the time of infinity in-focusing and at the wide-angle end in Numerical Embodiment 6 with the master lens ML attached. The lower part of FIG. 15 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 6 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 6 is mounted on the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

Numerical Embodiment 7 of Tele Converter Lens TCL
Basic lens data of Numerical Example 7 in which specific numerical values are applied to the teleconverter lens TCL shown in FIG. 6 is shown in [Table 15]. [Table 16] shows the focal length, F number (Fno), angle of view 2ω, back focus (BF), total length, of the entire lens system at the wide angle end and the telephoto end in a state of being attached to the master lens ML. And the image height value.

The teleconverter lens TCL according to Numerical Example 7 includes an aspheric surface. The values of the aspheric coefficients are shown below.
The 45th surface K = -9.421, A4 = -5.08731E-05, A6 = 2.65431E-07, A8 = -9.87829E-10, A10 = 1.74813E-12

In addition, the magnification β of the teleconverter lens TCL according to Numerical Example 7, the values of focal lengths of the lens units, and the values of the distance between the master lens ML will be described below.
β = 1.4
f1 = 55.00
f2 = -17.36
f3 = 52.69
Distance to master lens ML = 1.6082

In the teleconverter lens TCL according to Numerical Example 7, the first lens group G1 is composed of a biconvex positive lens L1.

The second lens group G2 includes, in order from the object side, a biconcave negative lens L2 having an aspheric surface formed on the object side, a biconvex positive lens L3, and a negative meniscus convex on the image surface side It is configured by a three-piece cemented lens composed of a lens L4. Between the first lens group G1 and the second lens group G2, the largest air gap is provided in the teleconverter lens TCL.

The third lens group G3 is composed of, in order from the object side, a double cemented lens of a negative meniscus lens L5 with a convex surface facing the image plane side and a biconvex lens L6.

The upper part of FIG. 16 shows various aberrations at the time of infinity in-focusing and at the wide-angle end in Numerical Embodiment 7 with the master lens ML attached. The lower part of FIG. 16 shows various aberrations at the time of focusing at infinity and at the telephoto end in Numerical Embodiment 7 with the master lens ML attached.

As can be seen from the respective aberration diagrams, in the state where the teleconverter lens TCL according to Numerical Example 7 is attached to the master lens ML, each aberration is well corrected in a well-balanced manner at the wide angle end and the telephoto end. It is clear that it has image performance.

[Other numerical data of each example]
[Table 17] shows values of the above-mentioned conditional expressions summarized for each numerical example. As can be seen from [Table 17], the value of each numerical example is within the numerical range for each conditional expression.

<5. Other Embodiments>
The technology according to the present disclosure is not limited to the description of the above embodiments and examples, and various modifications can be made.
For example, the shapes and the numerical values of the respective parts shown in the above numerical examples are merely examples of the implementation for implementing the present technology, and the technical scope of the present technology is interpreted limitedly by these. It is something that should not happen.

Further, in the above-described embodiment and examples, the configuration consisting of substantially three lens groups has been described, but the configuration may further include a lens having substantially no refractive power.

Further, for example, the present technology can have the following configurations.
[1]
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group.
[2]
The teleconverter lens as described in said [1] which satisfies the following conditional expressions.
2.2 <f3 / (-f2) <7.2 (2)
However,
f2: Focal length of the second lens group f3: Focal length of the third lens group.
[3]
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: Magnification of the teleconverter lens Lr: Distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane f2: Focal length of the second lens group.
[4]
The second lens group includes at least one cemented lens,
The teleconverter lens according to the above [3], wherein the at least one cemented lens includes, in order from the object side to the image surface side, a cemented doublet including a negative lens, a positive lens, and a negative lens.
[5]
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: the distance from the object-side principal point of the teleconverter lens to the lens surface of the tele-converter lens closest to the object (provided that the lens surface closest to the object is closer to the object than the object-side principal point Be negative)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.
[6]
The teleconverter lens as described in said [5] which satisfies the following conditional expressions.
0.3 <BF / h <1.9 (5)
However,
BF: Back focus in a state in which the teleconverter lens is attached to the master lens h: A maximum image height in a state in which the teleconverter lens is attached to the master lens.
[7]
The teleconverter lens according to any one of the above [1] to [6], which satisfies the following conditional expression.
(BF-et_i) / (BF + Lr)> 0.7 (6)
However,
BF: back focus with the teleconverter lens attached to the master lens et_i: distance from the lens surface closest to the image plane of the teleconverter lens to the image-side principal point of the teleconverter lens (the teleconverter lens Is negative when the image-side principal point of the lens is located on the object side of the lens surface closest to the image plane of the teleconverter lens)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.
[8]
The teleconverter lens according to any one of the above [1] to [7], which satisfies the following conditional expression.
0.03 <d12 / (-f) <0.2 (7)
However, d12: distance on the optical axis between the first lens group and the second lens group f: the focal length of the whole system of the teleconverter lens.
[9]
The teleconverter lens according to any one of the above [1] to [8], which satisfies the following conditional expression.
0.3 <| f1 / f | <1.5 (8)
However,
f1: Focal length of the first lens group f: Focal length of the whole system of the teleconverter lens.
[10]
The teleconverter lens according to any one of the above [1] to [9], which satisfies the following conditional expression.
0.05 <f2 / f <0.4 (9)
However,
f2: Focal length of the second lens group f: Focal length of the whole system of the teleconverter lens.
[11]
The second lens group includes at least one negative lens,
The teleconverter lens according to any one of the above [1] to [10], which satisfies the following conditional expression.
Nd_G2m> 1.85 (10)
However,
Nd_G2m: The highest value of the refractive index of the d-line of at least one negative lens included in the second lens group.
[12]
The teleconverter lens according to any one of the above [1] to [11], which satisfies the following conditional expression.
Nd_G3p <1.65 (11)
However,
Nd_G3p: A refractive index of d-line of a positive lens included in the third lens group.
[13]
The teleconverter lens according to any one of the above [1] to [12], which satisfies the following conditional expression.
15 <νd_G1 <35 (12)
However,
dd_G1: Abbe number of the positive lens included in the first lens group.
[14]
The teleconverter lens according to any one of the above [1] to [13], further comprising a lens having substantially no refractive power.
[15]
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group.
[16]
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: Magnification of the teleconverter lens Lr: Distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane f2: Focal length of the second lens group.
[17]
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: the distance from the object-side principal point of the teleconverter lens to the lens surface of the tele-converter lens closest to the object (provided that the lens surface closest to the object is closer to the object than the object-side principal point Be negative)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.
[18]
The optical apparatus according to any one of the above [15] to [17], wherein the zoom lens further includes a lens having substantially no refractive power.

This application claims priority based on Japanese Patent Application No. 2016-016981 filed on Feb. 1, 2016 in the Japanese Patent Office, and the entire contents of this application are hereby incorporated by reference. Incorporated in the application.

Various modifications, combinations, subcombinations, and modifications will occur to those skilled in the art depending on the design requirements and other factors, but they fall within the scope of the appended claims and their equivalents. Are understood to be

Claims

It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
2.2 <f3 / (-f2) <7.2 (2)
However,
f2: Focal length of the second lens group f3: Focal length of the third lens group.
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: Magnification of the teleconverter lens Lr: Distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane f2: Focal length of the second lens group.
The second lens group includes at least one cemented lens,
4. The teleconverter lens according to claim 3, wherein the at least one cemented lens includes, in order from the object side to the image surface side, a triple cemented lens including a negative lens, a positive lens, and a negative lens.
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
A teleconverter lens that enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: the distance from the object-side principal point of the teleconverter lens to the lens surface of the tele-converter lens closest to the object (provided that the lens surface closest to the object is closer to the object than the object-side principal point Be negative)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.
The teleconverter lens according to claim 5, which satisfies the following conditional expression.
0.3 <BF / h <1.9 (5)
However,
BF: Back focus in a state in which the teleconverter lens is attached to the master lens h: A maximum image height in a state in which the teleconverter lens is attached to the master lens.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
(BF-et_i) / (BF + Lr)> 0.7 (6)
However,
BF: back focus with the teleconverter lens attached to the master lens et_i: distance from the lens surface closest to the image plane of the teleconverter lens to the image-side principal point of the teleconverter lens (the teleconverter lens Is negative when the image-side principal point of the lens is located on the object side of the lens surface closest to the image plane of the teleconverter lens)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
However,
0.03 <d12 / (-f) <0.2 (7)
However, d12: distance on the optical axis between the first lens group and the second lens group f: the focal length of the whole system of the teleconverter lens.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
0.3 <| f1 / f | <1.5 (8)
However,
f1: Focal length of the first lens group f: Focal length of the whole system of the teleconverter lens.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
0.05 <f2 / f <0.4 (9)
However,
f2: Focal length of the second lens group f: Focal length of the whole system of the teleconverter lens.
The second lens group includes at least one negative lens,
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
Nd_G2m> 1.85 (10)
However,
Nd_G2m: The highest value of the refractive index of the d-line of at least one negative lens included in the second lens group.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
Nd_G3p <1.65 (11)
However,
Nd_G3p: A refractive index of d-line of a positive lens included in the third lens group.
The teleconverter lens according to claim 1, which satisfies the following conditional expression.
15 <νd_G1 <35 (12)
However,
dd_G1: Abbe number of the positive lens included in the first lens group.
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
-3.5 <(Rb2 + Rb1) / (Rb2-Rb1) <-0.18 (1)
However,
Rb1: Radius of curvature of lens surface on the object side of the positive lens included in the third lens group Rb2: Radius of curvature of the lens surface on the image plane side of the positive lens included in the third lens group.
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
0.05 <−f2 / (Lr * β) <0.45 (3)
However,
β: Magnification of the teleconverter lens Lr: Distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane f2: Focal length of the second lens group.
A master lens, an imaging device for outputting an imaging signal according to an optical image formed by the master lens, and a teleconverter lens detachably mounted between the master lens and the imaging device;
The teleconverter lens is
It has negative refractive power as a whole,
It comprises a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power in order from the object side to the image surface side,
Each of the first lens group and the third lens group is composed of two or less lenses including a positive lens,
The following conditional expressions are satisfied,
An optical device which enlarges the focal length of the master lens by being detachably mounted on the image plane side with respect to the master lens.
Lr / (et_o + Lr) <1.13 (4)
However,
et_o: the distance from the object-side principal point of the teleconverter lens to the lens surface of the tele-converter lens closest to the object (provided that the lens surface closest to the object is closer to the object than the object-side principal point Be negative)
Lr: A distance on the optical axis from the lens surface closest to the object side of the teleconverter lens to the lens surface closest to the image plane.