JP2015034903A5 - - Google Patents

Description

Attachment optical system and imaging apparatus having the same

The present invention relates to an attachment optical system , for example, when detachably mounted on an image side of an image pickup optical system (main lens system) used in an image pickup apparatus such as a digital camera or a surveillance camera, and performing automatic focusing (AF). Is preferred.

  In recent years, a digital single-lens reflex camera system (hereinafter referred to as “D-SLR”) as an imaging device includes a camera body having a solid-state imaging device such as a CCD or CMOS, and an imaging lens system that forms an optical image on an imaging sensor surface. And an interchangeable lens device provided. An imaging optical system used in an interchangeable lens apparatus is required to have a focusing function that can perform an automatic focusing operation quickly.

On the other hand, D-SLR is required to perform not only still image shooting but also moving image shooting. In moving image shooting, it is necessary to repeat the focusing operation that is performed during still image shooting. An attachment optical system is detachably mounted on the image side of the imaging optical system (main lens system), and all or a part of the lens group of the attachment optical system is moved in the optical axis direction to perform automatic focus adjustment of the imaging optical system. An imaging apparatus for performing this is known (Patent Documents 1 and 2). As automatic focus adjustment at this time, a so-called contrast AF method is often used.

  In the focusing operation, the focusing lens group is vibrated at high speed in the optical axis direction (hereinafter referred to as “wobbling”) to detect the direction of deviation from the focused state. After wobbling, a signal component in a specific frequency band of the image area is detected from the output signal of the image sensor, and the optimum position of the focusing lens group that is in focus is calculated.

Thereafter, the focusing lens group is moved to the optimum position, and focusing is completed. In Patent Document 1, focusing is performed by moving the entire attachment optical system (rear converter lens). In Patent Document 2, a lens unit having a positive positive refractive power, a lens unit having a negative refractive power for wobbling, and an image side lens unit having a fixed positive refractive power are used. A focusing operation is performed by a lens group having a negative refractive power.

Japanese Patent Laid-Open No. 7-27975 JP 2011-175054 A

The attachment optical system is mounted on the image side of the main lens system, the utilizing attachment optical system for detecting focus by contrast AF method at high speed, it is necessary to drive at high speed focusing lens group at the time of wobbling. When performing focusing operation by wobbling, if the weight of the focusing lens group is heavy, a motor and an actuator for driving the focusing lens group at a high speed become large. For this reason, the maximum diameter of the lens barrel is increased, and the interchangeable lens device is increased in size.

The attachment optical system is mounted on the image side of the main lens system, a fast detection of the focus position of the entire system at the attachment optical system, moreover in order to perform a high accuracy, by appropriately setting the lens construction of attachment optical system Becomes important. In particular, it is important to appropriately set the lens configuration, refractive power, and the like of a lens unit that is driven to vibrate for the arrangement of refractive power and wobbling of each lens unit constituting the attachment optical system . When the lens configuration of the attachment optical system is inappropriate, it becomes difficult to perform automatic focus detection at high speed and with high accuracy using the attachment optical system .

For example, when focusing is performed by driving the entire attachment optical system , it is difficult to focus at high speed because the focusing lens group is heavy. In order to perform wobbling at a high speed, even if the focusing lens group is composed of a single lens, if the lens configuration is inappropriate, there are many aberration variations and it is difficult to detect the focus with high accuracy.

The present invention is detachable from the image side of the imaging optical system (main lens system), provides the entire system focus state at high speed, yet the imaging apparatus having the same attachment optical system and can be detected with high precision With the goal.

Attachment optical system of the present invention is an attachment optical system detachably mountable to an image side of the imaging optical system, the attachment optical system is arranged in order from the object side to the image side, a positive first lens refractive power A second lens unit having a negative refractive power and a third lens unit having a positive refractive power,
The absolute value of the focal length of the second lens unit is smaller than the absolute value of the focal length of the first lens unit and the absolute value of the focal length of the third lens unit,
The first lens unit and the third lens unit are immovable in the optical axis direction of the attachment optical system, and the second lens unit is movable in the optical axis direction,
The focal length of the first lens unit is f1, the focal length of the second lens unit is f2, and the distance on the optical axis from the most object side lens surface to the most image side lens surface of the attachment optical system is L. and when,
0.1 <L / f1 <1.0
0.2 <| L / f2 | <1.5
It satisfies the following conditional expression.

According to the present invention, it is possible to obtain an attachment optical system that can be attached to and detached from the image side of the imaging optical system (main lens system) and can detect the in-focus state of the entire system at high speed and with high accuracy.

Sectional view of the lens when the attachment optical system of Example 1 is attached to the main lens system (A), (B) Aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 1 is attached to the main lens system Sectional view of the lens when the attachment optical system of Example 2 is attached to the main lens system (A), (B) Aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 2 is mounted on the main lens system Sectional view of the lens when the attachment optical system of Example 3 is attached to the main lens system (A), (B) Aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 3 is attached to the main lens system Sectional view of the lens when the attachment optical system of Example 4 is mounted on the main lens system (A), (B) Aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 4 is attached to the main lens system Sectional view of the lens when the attachment optical system of Example 5 is mounted on the main lens system (A), (B) Aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 5 is attached to the main lens system Schematic diagram of main parts of an imaging apparatus of the present invention (A), (B) Aberration diagrams at the wide-angle end and the telephoto end of the main lens system

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The attachment optical system LA of the present invention is detachably mounted on the image side of the imaging optical system (main lens system) LM. Then, it is used to detect the in-focus (focus) direction of the entire system by minutely vibrating at least some of the lens units constituting the attachment optical system LA in the optical axis direction. The attachment optical system according to the present invention includes, in order from the object side to the image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power. .

The absolute value of the focal length of the second lens unit is smaller than the absolute value of the focal length of the first lens unit and the absolute value of the focal length of the third lens unit . The second lens unit is configured to be movable in the optical axis direction for focus detection of the entire system. The first lens unit and the third lens unit do not move in the optical axis direction. Here, the lens unit means a condenser lens composed of a single lens or a plurality of lenses.

FIG. 1 is a lens cross-sectional view when the attachment optical system of Example 1 is attached to the main lens system. FIGS. 2A and 2B are aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 1 is attached to the main lens system. FIG. 3 is a lens cross-sectional view when the attachment optical system of Example 2 is attached to the main lens system. FIGS. 4A and 4B are aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 2 is attached to the main lens system.

FIG. 5 is a lens cross-sectional view when the attachment optical system of Example 3 is attached to the main lens system. FIGS. 6A and 6B are aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 3 is mounted on the main lens system. FIG. 7 is a lens cross-sectional view when the attachment optical system of Example 4 is attached to the main lens system. 8A and 8B are aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system according to Example 4 is mounted on the main lens system.

FIG. 9 is a lens cross-sectional view when the attachment optical system of Example 5 is attached to the main lens system. FIGS. 10A and 10B are aberration diagrams at the wide-angle end and the telephoto end when the attachment optical system of Example 5 is attached to the main lens system.

FIG. 11 is a schematic diagram of a main part of the imaging apparatus of the present invention. 12A and 12B are aberration diagrams at the wide-angle end and the telephoto end of the main lens system. In the lens cross-sectional view, LM is a main lens system (imaging optical system), which is a zoom lens. The main lens system may be an imaging optical system having a single focal length. LA is an attachment optical system , and includes a first lens unit L1, a second lens unit L2, and a third lens unit L3.

  The main lens system LM includes, in order from the object side to the image side, a first lens unit B1 having a positive refractive power, a second lens unit B2 having a positive refractive power, a third lens unit B3 having a negative refractive power, and a positive refractive power. The fourth lens unit B4 and the fifth lens unit B5 having a positive refractive power. P is an aperture stop. IMG is an image plane.

  During zooming from the wide-angle end to the telephoto end, the second lens unit B2 and the third lens unit B3 move toward the image side, and the fourth lens unit B4 moves along a locus that is convex toward the image side. During zooming, the first lens unit B1 and the fifth lens unit B5 do not move. Here, any zoom type of the main lens system LM may be used. In the spherical aberration diagram, the solid line is the d line, and the two-dot chain line is the g line. In the astigmatism diagram, the solid line is the sagittal image plane, and the dotted line is the meridional image plane. The lateral chromatic aberration is shown for the g-line. Fno is an F number, and ω is a half angle of view (degrees).

By mounting the attachment optical system LA of the present invention on the image side of the main lens group LM, it is easy to make the entire attachment optical system LA compact. Further, by performing focus detection by driving the second lens unit L2 having the largest absolute value of refractive power in the optical axis direction, the focus sensitivity is increased, and the entire attachment optical system LA is easily reduced in size. .

The shift direction from the in-focus state is detected by detecting the change in the contrast value of the image obtained on the image plane when the second lens unit L2 is driven with minute vibration in the optical axis direction. The second lens unit L2 is preferably composed of a single lens. By configuring the second lens unit L2 with a single lens, the second lens unit L2 for focusing of the attachment optical system LA can be reduced in weight, so that it is easy to detect the deviation direction from the in-focus state at high speed.

When the attachment optical system LA is attached to the main lens system LM, it is not preferable that the specifications and optical performance of the main lens system LM change. For example, if the focal length of the main lens system LM changes when the attachment optical system LA is attached to the main lens system LM, it is not preferable because the shooting angle of view changes. Also, if the exit pupil position fluctuates greatly when the attachment optical system LA is attached to the main lens system LM, problems such as peripheral light reduction and shading may occur, which is not preferable.

Furthermore, optical performance will be degraded when wearing the attachment optical system LA when the attachment optical system LA is left aberrations, it is not preferred. In order to reduce the change in the specification of the main lens system LM, it is preferable that the focal length of the attachment optical system LA is sufficiently longer than the focal length of the main lens system LM.

The attachment optical system LA of each embodiment of the present invention includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens having a positive refractive power. It consists of unit L3. The attachment optical system LA is composed of three lens units, and has a symmetrical refractive power arrangement, so that the specifications of the main lens system LM are maintained when mounted on the main lens system LM, and optical performance is less deteriorated. .

  There are two types of symmetrical refractive power arrangements: negative, positive and negative refractive power lens units and positive, negative and positive refractive power lens units. When the refractive power arrangement is symmetric, the refractive power of the middle lens unit becomes strong, and therefore it is preferable to perform focusing with the middle lens unit. In order to reduce the weight of the focusing lens unit, it is necessary to reduce the diameter of the focusing lens unit. The diameter of the focusing lens unit is determined by the height of the off-axis light beam.

  When a lens unit with negative, positive, and negative refractive power is arranged, the off-axis light beam diverges in the lens unit with the negative refractive power closest to the object side. The diameter of the lens unit having a positive refractive power is increased. On the other hand, if a lens unit having positive, negative, and positive refractive power is arranged, the off-axis light beam is converged by the lens unit having positive refractive power on the object side, and the incident height of the off-axis light beam can be reduced. The diameter of the lens unit having the negative refractive power in the middle can be reduced.

In the attachment optical system LA of the present invention, the lens unit having the negative refractive power in the middle is arranged for focusing in the arrangement of the lens units having positive, negative, and positive refractive power, and the refractive power arrangement of each lens unit is appropriately set. , Focus sensitivity is high. The focus lens unit is also miniaturized. When the attachment optical system LA is mounted on the image side of the imaging optical system LM, the focal length of the entire system may be unchanged or variable. A

The driving means for driving the second lens unit L2 of the attachment lens LA may be provided in the main lens system LM or the imaging device (camera body) in addition to the lens barrel that holds the attachment optical system LA. In each embodiment, the focal length of the first lens unit L1 is f1, and the focal length of the second lens unit L2 is f2. Let L be the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side of the attachment optical system LA. At this time,
0.1 <L / f1 <1.0 (1)
0.2 <| L / f2 | <1.5 (2)
The following conditional expression is satisfied.

Conditional expression (1) defines the ratio of the optical total length of the attachment optical system LA to the focal length of the first lens unit L1. If the lower limit of conditional expression (1) is not reached, the refractive power of the first lens unit L1 becomes too small, so that the convergence of the off-axis light beam becomes insufficient and the diameter of the second lens unit L2 becomes large, which is not preferable. If the upper limit is exceeded, the refractive power of the first lens unit L1 becomes too large, and it becomes difficult to correct various aberrations generated by the first lens unit L1, and the optical performance when attached to the main lens system LM is not preferable. .

Conditional expression (2) defines the ratio of the optical total length of the attachment optical system LA to the focal length of the second lens unit L2. If the lower limit of conditional expression (2) is not reached, the refractive power of the second lens unit L2 becomes too small and the focus sensitivity becomes low, which is not preferable. If the upper limit is exceeded, the refractive power of the second lens unit L2 becomes too large, it becomes difficult to correct various aberrations generated by the second lens unit L2, and the optical performance when attached to the main lens system LM is greatly reduced, which is preferable. Absent.

  On the other hand, if the upper limit is exceeded, the change in the focal length when the second lens unit L2 is driven becomes large, the photographing angle of view fluctuates greatly, and the photographer is uncomfortable. More preferably, the numerical ranges of conditional expressions (1) and (2) are set as follows.

0.18 <L / f1 <0.55 (1a)
0.30 <| L / f2 | <0.90 (2a)
As described above, according to each embodiment, it is possible to obtain a compact attachment optical system that is attached to the main lens system LM and that can detect the shift direction from the in-focus position at high speed. Next, features other than those described above of the attachment optical system of the present invention will be described.

In order to detect the deviation direction from the in-focus position, it is necessary to sufficiently change the contrast value of the image obtained when the focusing lens unit is driven to vibrate. In the case of a lens system with a bright Fno (F number), since the depth of focus is shallow, the contrast value changes greatly with a small drive amount.
On the other hand, when Fno is darkened by narrowing the aperture stop of a lens system with a dark Fno or when the lens system is darkened, the depth of focus is deep. Therefore, in order to change the contrast value by the same amount, the driving amount of the lens unit for focusing needs to be increased. There is. However, if the driving amount of the lens unit for focusing is increased, it becomes difficult to detect the deviation direction from the in-focus direction at high speed.

  Here, the ratio Δxp / Δxf of the movement amount Δxp of the paraxial image plane in the optical axis direction when the lens unit for focusing is driven by the minute amount Δxf in the optical axis direction is defined as the focus sensitivity. By increasing the focus sensitivity, it becomes easy to detect the deviation direction from the in-focus direction at high speed even when the depth of focus is deep. On the other hand, if the focus sensitivity is increased too much, the positioning accuracy of the focusing lens unit increases, and the required processing accuracy becomes too high, which is not preferable.

The focus sensitivity is determined by using the combined lateral magnification βf of the focusing lens unit and the combined lateral magnification βR of the lens unit existing on the image side of the focusing lens unit. Δxp / Δxf = (βf ² −1) × βR ² ... (x1)
Can be expressed as However, when there is no lens unit on the image side of the focusing lens unit, the combined lateral magnification βR in the equation (x1) is 1. In order to set the focus sensitivity to an appropriate value, it is important to select an appropriate refractive power arrangement of the lens system and a lens unit for focusing.

In the attachment optical system LA of the present invention, it is preferable to satisfy one or more of the following conditional expressions. Let the focal length of the third lens unit L3 be f3. And sk a distance on the optical axis to the image plane from the lens surface on the most image side of the attachment optical system LA in the case of mounting the attachment optical system LA on the image side of the imaging optical system LM. Let f be the focal length of the attachment optical system LA. The lateral magnification of the second lens unit L2 is β2, and the lateral magnification of the third lens unit L3 is β3. At this time, it is preferable to satisfy one or more of the following conditional expressions.

1.2 <β2 <3.0 (3)
0.2 <f1 / f3 <4.0 (4)
0.7 <L / sk <2.5 (5)
−0.03 <(sk + L / 2) / f <0.05 (6)
0.9 <| β2 ² −1 | × β3 ² <4.5 (7)
Next, the technical meaning of each conditional expression described above will be described.

The attachment optical system LA of the present invention is a reduction system because the focusing lens unit has a negative refractive power, and the lateral magnification β2 is larger than 1. Accordingly, the focus sensitivity is optimized by setting the lateral magnification β2 large. If the lower limit of conditional expression (3) is not reached, the driving amount of the focusing lens unit L2 required for detecting the direction of deviation from the in-focus position becomes too large, which is not preferable. Exceeding the upper limit is not preferable because the positioning accuracy of the focusing lens unit L2 becomes too high.

Conditional expression (4) defines the ratio of the focal length of the first lens unit L1 to the focal length of the third lens unit L3. If the lower limit of conditional expression (4) is not reached, it is not preferable because when the attachment optical system LA is mounted on the main lens system LM, the exit pupil position becomes too short and shading occurs. If the upper limit of conditional expression (4) is exceeded, it will be difficult to correct various aberrations generated by the third lens unit L3, and the optical performance will deteriorate.

Conditional expression (5) defines the ratio of the optical total length of the attachment optical system LA to the back focus. If the lower limit of conditional expression (5) is not reached, the back focus becomes too long, and the total lens length (distance from the first lens surface to the image plane) when the attachment optical system LA is mounted becomes long. Exceeding the upper limit is not preferable because the back focus becomes too short and interferes with the main body of the imaging apparatus when used in the imaging apparatus.

Conditional expression (6) defines the total optical length of the attachment optical system LA, the back focus, the focal length of the attachment optical system LA, and the like. Exceeding the upper limit of conditional expression (6) is not preferable because the focal length fluctuates to the wide angle side (shortening direction) when the attachment optical system LA is attached to the main lens system LM. In particular, if the focal length fluctuates to the wide angle side, vignetting may occur in the main lens system LM, which is not preferable. Below the lower limit, it is not preferable because the focal length fluctuates to the telephoto side (in the longer direction) when the attachment optical system LA is attached to the main lens system LM.

  Conditional expression (7) defines the focus sensitivity of the second lens unit L2. If the lower limit of conditional expression (7) is not reached, the driving amount of the second lens unit L2 necessary for detecting the direction of deviation from the in-focus position becomes too large, which is not preferable. Exceeding the upper limit is not preferable because the positioning accuracy of the second lens unit L2 becomes too high. More preferably, the numerical ranges of conditional expressions (3) to (7) are set as follows.

1.5 <β2 <2.2 (3a)
0.25 <f1 / f3 <3.30 (4a)
0.9 <L / sk <2.2 (5a)
−0.01 <(sk + L / 2) / f <0.03 (6a)
1.2 <| β2 ² −1 | × β3 ² <2.5 (7a)

As an imaging apparatus having a function of recording image data generated by an imaging optical system and an imaging sensor (imaging element) as a moving image, the so-called D-SLR uses the attachment optical system LA for automatic focusing during moving image shooting. Also good. During moving image shooting or when the live view function is activated, the aperture stop of the imaging optical system may be throttled. When Fno becomes dark, the depth of focus becomes shallow, so it is preferable to increase the driving amount of the second lens unit L2.

The attachment optical system LA of the present invention has a communication means with the imaging apparatus main body and / or the lens main body, and has a control means for determining the driving amount of the second lens unit L2 based on the optical information at the time of photographing. It is preferable to have it. When the attachment optical system is mounted on the image side of the main lens system, the distance from the lens surface closest to the image side of the main lens system to the image plane is when the attachment optical system LA is not mounted on the image side of the main lens system. This is longer than the distance from the lens surface closest to the image side of the main lens system to the image plane. This facilitates downsizing of the attachment optical system .

The main lens system to which the attachment optical system LA of the present invention is attached may have a focusing mechanism separately from the attachment optical system LA. When focusing is performed by driving the second lens unit L2 of the attachment optical system LA in the direction of the optical axis, the amount of movement for focusing increases particularly when the second lens unit L2 is mounted on a main lens system having a long focal length. Therefore, focusing may be performed with a part of the main lens system.

FIG. 11 is a schematic diagram of a main part of a digital still camera (imaging device) using a zoom lens having the attachment optical system of each embodiment. In FIG. 11, reference numeral 20 denotes a camera body, and 21 denotes an imaging optical system constituted by a zoom lens having any one of the attachment optical systems described in each embodiment. Reference numeral 22 denotes a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the imaging optical system 21 and is built in the camera body 20.

  The imaging apparatus of the present embodiment can be applied to both a single-lens reflex camera with a quick return mirror, a single-lens reflex camera with a quick return mirror, and a mirrorless single-lens reflex camera without a quick return mirror.

Next, numerical examples corresponding to the main lens system and Examples 1 to 5 of the present invention will be described. In the numerical example, the surface number i indicates the order from the object side, ri is the radius of curvature of the i-th (i-th surface) surface in order from the object side, and di is the i-th and i + 1-th in order from the object side. Lens thickness or air spacing between ndi and νdi are respectively the refractive index and Abbe number at the d-line of the i-th optical material in order from the object side. In Numerical Examples 1 to 5 of the attachment optical system shows a case in which inserting the attachment optical system on the image side of the main lens system. In each numerical example, surface numbers 1 to 42 are main lens systems.

In Numerical Example 1, the surface numbers 43 to 48 are attachment optical systems . In Numerical Example 2, the surface numbers 43 to 51 are attachment optical systems . In Numerical Example 3, the surface numbers 43 to 49 are attachment optical systems . In Numerical Example 4, the surface numbers 43 to 50 are attachment optical systems . In Numerical Example 5, surface numbers 43 to 50 are attachment optical systems . Table 1 shows the relationship between the above-described conditional expressions and various numerical values in the numerical examples. The main lens LM to which the attachment optical system of the present invention is attached is shown below.

[Main lens system] Numerical examples

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 54.00
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium telephoto focal length 72.13 135.02 193.99
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 237.36 237.36 237.35
BF 54.00 54.00 54.00

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

The main lens to which the attachment optical system of the present invention is attached is not limited to this, and can be attached to various main lenses. Next, numerical examples in which the attachment optical system of the present invention is attached to the main lens LM will be described.

[Numerical example when an attachment optical system is attached to the main lens system]
[Numerical Example 1]

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 18.92
43 74.862 3.13 1.80 100 35.0
44 -530.100 3.13
45 -151.984 1.44 1.83400 37.2
46 62.880 8.78
47 -2107.198 4.18 1.51633 64.1
48 -89.880 16.77
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium Telephoto focal length 72.12 135.00 193.96
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 239.70 239.71 239.71
BF 16.77 16.77 16.77

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

[Numerical Example 2]

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 17.06
43 68.443 3.92 1.83400 37.2
44 -350.300 1.30
45 -441.548 2.51 1.74077 27.8
46 -101.467 1.48 1.60562 43.7
47 74.892 5.50
48 -73.086 1.44 1.83400 37.2
49 41.249 3.00
50 43.187 8.26 1.51633 64.1
51 -49.071 13.87
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium telephoto focal length 72.13 135.02 193.99
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 241.70 241.70 241.70
BF 13.87 13.87 13.87

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

[Numerical Example 3]

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 17.00
43 65.054 5.79 1.78800 47.4
44 -56.882 1.20 1.58913 61.1
45 85.619 6.85
46 -57.297 1.44 1.83481 42.7
47 44.015 3.00
48 50.164 8.15 1.51633 64.1
49 -43.710 14.78
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium telephoto focal length 72.13 135.02 193.99
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 241.57 241.57 241.57
BF 14.78 14.78 14.78

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

[Numerical Example 4]

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 16.00
43 40.082 6.10 1.67270 32.1
44 -167.971 1.89
45 -134.676 1.40 1.80610 33.3
46 34.180 6.11
47 -175.746 1.40 1.63930 44.9
48 97.497 3.00
49 49.267 6.40 1.51633 64.1
50 -104.895 14.84
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium telephoto focal length 72.13 135.02
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 240.49 240.49 240.49
BF 14.84 14.84 14.84

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

[Numerical Example 5]

Surface data surface number rd nd νd
1 289.168 2.80 1.74950 35.3
2 113.925 0.96
3 136.073 8.52 1.49700 81.5
4 -299.563 0.10
5 73.100 6.66 1.49700 81.5
6 190.324 (variable)
7 51.002 2.20 1.80518 25.4
8 43.113 1.55
9 51.352 8.51 1.49700 81.5
10 -15551.359 (variable)
11 -1008.202 1.40 1.80 400 46.6
12 34.486 5.76
13 -81.184 1.40 1.49700 81.5
14 37.378 5.33 1.84666 23.9
15 352.647 2.83
16 -57.635 1.40 1.69680 55.5
17 ∞ (variable)
18 153.392 5.04 1.67790 55.3
19 -90.419 0.15
20 1051.897 6.50 1.49700 81.5
21 -41.538 1.45 1.83400 37.2
22 -104.544 (variable)
23 (Aperture) ∞ 0.39
24 59.410 3.24 1.80 400 46.6
25 173.026 0.49
26 42.341 3.38 1.77250 49.6
27 62.133 1.85
28 350.253 1.60 1.74000 28.3
29 34.471 6.87 1.49700 81.5
30 -135.210 3.70
31 260.157 3.69 1.80518 25.4
32 -64.844 1.40 1.58313 59.4
33 33.633 4.89
34 -67.742 1.40 1.74400 44.8
35 1881.652 3.46
36 192.183 4.01 1.80 400 46.6
37 -73.493 2.48
38 164.169 8.87 1.48749 70.2
39 -29.142 2.00 1.83400 37.2
40 -391.790 4.90
41 78.138 3.40 1.83400 37.2
42 306.537 15.22
43 61.602 6.26 1.63980 34.5
44 -90.190 2.14
45 -72.803 1.98 1.72342 38.0
46 -49.140 1.20 1.80 400 46.6
47 61.469 6.25
48 -105.110 1.20 1.84666 23.9
49 151.375 6.09 1.77250 49.6
50 -57.730 18.60
Image plane ∞

Various data Zoom ratio 2.69
Wide angle Medium telephoto focal length 72.14 135.03 194.00
F number 2.90 2.90 2.90
Half angle of view (degrees) 10.72 5.78 4.03
Image height 13.66 13.66 13.66
Total lens length 242.29 242.29 242.29
BF 18.60 18.60 18.60

d 6 10.72 26.51 33.79
d10 1.58 13.45 17.30
d17 29.09 14.44 1.09
d22 17.39 4.38 6.62

LM Main lens P Aperture stop LA Attachment optical system L1 First lens unit L2 Second lens unit L3 Third lens unit IMG Image plane

Claims (9)

A attachment optical system detachably mountable to an image side of the imaging optical system, the attachment optical system is arranged in order from the object side to the image side, a first lens unit of positive refractive power, a negative refractive power 2 lens units and a third lens unit with positive refractive power,
The absolute value of the focal length of the second lens unit is smaller than the absolute value of the focal length of the first lens unit and the absolute value of the focal length of the third lens unit,
The first lens unit and the third lens unit are immovable in the optical axis direction of the attachment optical system, and the second lens unit is movable in the optical axis direction,
The focal length of the first lens unit is f1, the focal length of the second lens unit is f2, and the distance on the optical axis from the most object side lens surface to the most image side lens surface of the attachment optical system is L. and when,
0.1 <L / f1 <1.0
0.2 <| L / f2 | <1.5
An attachment optical system characterized by satisfying the following conditional expression: The attachment optical system according to claim 1, wherein the second lens unit includes a single lens. When the lateral magnification of the second lens unit is β2,
1.2 <β2 <3.0
The attachment optical system according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the third lens unit is f3,
0.2 <f1 / f3 <4.0
The attachment optical system according to any one of claims 1 to 3, wherein the following conditional expression is satisfied. When the sk a distance on the optical axis to the image plane from the lens surface on the most image side of the attachment optical system at the time of mounting the attachment optical system on the image side of the imaging optical system,
0.7 <L / sk <2.5
The attachment optical system according to claim 1, wherein the following conditional expression is satisfied. The attachment of the focal length of the optical system f, sk the distance on the optical axis to the image plane from the lens surface on the most image side of the attachment optical system at the time when the attachment optical system mounted on the image side of the imaging optical system And when
−0.03 <(sk + L / 2) / f <0.05
The attachment optical system according to any one of claims 1 to 5, wherein the following conditional expression is satisfied. When the lateral magnification of the second lens unit is β2, and the lateral magnification of the third lens unit is β3,
0.9 <| β2 ² −1 | × β3 ² <4.5
The attachment optical system according to claim 1, wherein the following conditional expression is satisfied. Distance on the optical axis to the image plane from the lens surface on the most image side of the imaging optical system at the time of mounting the attachment optical system on the image side of the imaging optical system, the attachment optical system of the imaging optical system according to any one of claims 1 to 7, wherein the longer than the distance on the optical axis to the image plane from the lens surface on the most image side of the imaging optical system at the time when not mounted to the image side Attachment optical system . An imaging apparatus comprising: an imaging optical system; the attachment optical system according to any one of claims 1 to 8; and an imaging element that receives an image formed by the attachment optical system .