JP2012042864A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus including a zoom lens which is advantageous in shortening of the entire length, while securing a variable power ratio and an angle of view at a wide angle end.SOLUTION: In the imaging apparatus, a zoom lens includes in order from the object side to the image side: a first lens group which includes a reflection member having a reflection surface, and has positive refractive power; a second lens group having negative refractive power; and a rear lens group which includes at least three lens groups including, in order from the object side, a third lens group, a fourth lens group and a fifth lens group, and has positive refractive power as a whole. The zoom lens further includes a brightness diaphragm arranged between the second lens group and the fourth lens group. In the zoom lens, when power is varied from a wide angle end to a telephoto end, the first lens group is fixed, the second lens group is moved to be positioned closer to an image side at the telephoto end than at the wide angle end, and each space put between the respective lens groups is changed. The first lens group has, in order from the object side to the image side, a negative lens component, the reflection member and a rear sub-lens group having a first positive lens and a second positive lens, the second lens group has a plurality of lenses including a negative lens, and the zoom lens satisfies a predetermined conditional expression.

Description

  The present invention relates to an imaging apparatus in which the thickness direction of the imaging apparatus is reduced by disposing a reflecting member that reflects an optical path in a zoom lens.

2. Description of the Related Art Conventionally, there has been known a zoom lens in which a reflecting member that reflects an optical path is disposed in the optical path of the zoom lens and the imaging device (particularly, a digital camera) is thinned in the thickness direction.
Particularly, the reflecting member is arranged in the first lens group which is the most object side lens group in the zoom lens, and the zoom lens is fixed to the apparatus main body so that the zoom lens is not extended from the apparatus main body. The device is known. Thus, by eliminating the extension of the zoom lens from the apparatus main body, it is possible to improve the dust resistance, waterproofness, and impact resistance of the imaging apparatus.

On the other hand, in addition to the need for thinner imaging devices, recently, there is a need for a zoom lens with a high zoom ratio and a wide-angle end angle of view.
As a zoom lens corresponding to the need for such an imaging apparatus, a zoom lens disclosed in Patent Document 1 has been proposed.

  The zoom lens disclosed in Patent Document 1 includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an aperture stop, a third lens group having a positive refractive power, and a negative refractive power. The fourth lens group and the fifth lens group having positive refractive power, a reflecting member (here, a right-angle prism) is disposed in the first lens group, and the second lens group is used for zooming from the wide-angle end to the telephoto end. The aperture stop, the third lens group, and the fifth lens group are moved independently to achieve a high zoom ratio of about 10 times. The zoom lens disclosed in Patent Document 1 secures the zooming function of the second lens group and achieves a high zoom ratio by increasing the amount of movement of the second lens group. In order to easily secure the positive refractive power of the first lens group, a negative lens, a reflecting member (a right-angle prism) and two positive lenses on the image side are arranged in order from the object side, and two positive refractive powers are set. Aberration is reduced by sharing the lens.

JP 2009-236973 A

  However, although the zoom lens disclosed in Patent Document 1 can achieve a wide angle of view and a high zoom ratio, since the amount of movement of the second lens group is large, the first lens group, the brightness stop, The distance is large. Therefore, the effective diameter of the first lens group is increased, and the thickness of the prism is increased according to the size of the effective diameter. In particular, since the angle of view at the wide-angle end is secured, the effective diameter at the wide-angle end tends to increase further, and the thickness of the imaging device cannot be reduced as the prism becomes larger.

  Furthermore, in the zoom lens disclosed in Patent Document 1, the variation in chromatic aberration due to zooming is large, and the chromatic aberration of magnification becomes conspicuous if an attempt is made to shorten the overall length.

  The present invention has been made in view of the above, and an object of the present invention is to provide an imaging apparatus including a zoom lens that is advantageous in shortening the overall length while ensuring a zoom ratio and a field angle at the wide-angle end. Is to provide. A further object is to provide an imaging apparatus equipped with a zoom lens that is advantageous for both shortening the overall length and ensuring optical performance.

In order to solve the above-described problems and achieve the object, an imaging apparatus according to a first aspect of the present invention includes an imaging device having a zoom lens and an imaging device having an imaging surface that converts an image obtained by the zoom lens into an electrical signal. The zoom lens includes a first lens group having a reflecting member having a reflecting surface for reflecting an optical path in order from the object side to the image side, and having a positive refractive power, and a first lens group having a negative refractive power. A second lens group, and a rear lens group including at least three lens groups including a third lens group, a fourth lens group, and a fifth lens group in order from the object side, and having a positive refractive power as a whole. An aperture stop is disposed between the lens group and the fourth lens group. When zooming from the wide-angle end to the telephoto end, the first lens group is fixed, and the second lens group is more telephoto than the wide-angle end. Move so that it is positioned on the image side at the end. The first lens group includes, in order from the object side to the image side, a negative lens component, a reflecting member, a rear sub-lens group having a first positive lens and a second positive lens. The second lens group has a plurality of lenses including a negative lens, and satisfies the following conditional expressions (1), (2), and (AA).
7 <f _T / f _W <30 (1)
0.5 <f _W /IH<1.38 (2)
−0.2 <f _2G / f _T <−0.05 (AA)
here,
f _T is the focal length of the entire zoom lens system at the telephoto end,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
IH is the maximum image height of the effective imaging area of the imaging surface,
f _2G is the focal length of the second lens group,
And
The lens component is a lens body divided by a surface in contact with air on the lens effective surface, and is a single lens or a cemented lens.

According to the first aspect, the optical path is reflected by the reflecting member in the first lens group, which is advantageous for making the imaging device thinner.
It is easy to give the second lens group a zooming function with a constant overall length, and it is easy to secure a zoom ratio and reduce aberration fluctuations by using a plurality of lens groups for the zoom lens.

  Further, two positive lenses are used in the first lens group in order to ensure the zoom ratio. This is advantageous for correcting monochromatic aberration. In addition, a plurality of lenses are included in the second lens group in order to facilitate the reduction of aberrations even if the negative refractive power of the second lens group is ensured.

Conditional expression (1) specifies a preferable zoom ratio.
By making sure that the lower limit of conditional expression (1) is not exceeded, the user can enjoy the change in the angle of view, and the subject can be easily put in the frame in various shooting scenes.
By not exceeding the upper limit of conditional expression (1), it is easy to suppress camera shake caused by an increase in the F number at the telephoto end and noise generation due to an increase in sensitivity.

Conditional expression (2) corresponds to a preferred angle of view at the wide-angle end.
By making it not fall below the lower limit of conditional expression (2), it becomes easy to suppress the occurrence of distortion, and it becomes easy to suppress the increase in the number of lenses in the first lens group.
By making sure that the upper limit of conditional expression (2) is not exceeded, it is advantageous for shooting in places where the distance between the apparatus and the subject cannot be made large, such as indoor shooting conditions.

Conditional expression (AA) specifies a preferable focal length of the second lens group.
By appropriately suppressing the refractive power of the second lens unit so as not to fall below the lower limit of conditional expression (AA), excessive curvature of each lens surface is prevented, and various aberrations (particularly distortion and astigmatism at the wide-angle end) are prevented. This is advantageous in reducing aberration, axial chromatic aberration, lateral chromatic aberration, and coma aberration at the telephoto end. In addition, the influence of eccentricity can be suppressed.
By not exceeding the upper limit of the conditional expression (AA), the movement range of the second lens group can be reduced even if the zoom ratio is secured, which is advantageous for shortening the overall length of the zoom lens and thinning the device. Become. In addition, since the entrance pupil position can be made shallow, it is advantageous for securing peripheral performance at the wide-angle end, and it is advantageous for securing the angle of view although it is small.

  When the zoom lens has a focusing function, each of the above-described configurations is configured in a state where it is focused on the farthest distance. Similarly, in the subsequent inventions, each of the above-described configurations is a configuration in which the farthest distance is in focus.

As a second aspect of the present invention, the rear lens group includes at least three lens units having a positive refractive power. Instead of conditional expressions (1) and (2), the following conditional expressions (4) and (3 ) May be satisfied.
2.35 <| Δ _2G / f _W | <15 (4)
16.5 <| ν _dp1 −ν _dp2 | <80 (3)
here,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, with the movement toward the image side being a positive sign,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
ν _dp1 is the Abbe number based on the d-line of the first positive lens in the first lens group,
ν _dp2 is the Abbe number based on the d-line of the second positive lens in the first lens group.

An image pickup apparatus according to a second aspect of the present invention is an image pickup apparatus including a zoom lens and an image pickup element having an image pickup surface that converts an image obtained by the zoom lens into an electric signal. In turn, a first lens group having a reflecting member having a reflecting surface for reflecting the optical path and having a positive refractive power, a second lens group having a negative refractive power, a third lens group in order from the object side, A rear lens group that includes a plurality of lens groups including a fourth lens group and a fifth lens group and has a positive refractive power as a whole, and is arranged between the second lens group and the fourth lens group. The first lens unit is fixed at the time of zooming from the wide-angle end to the telephoto end, and the second lens unit is moved to be positioned closer to the image side at the telephoto end than at the wide-angle end. The interval between each of them changes, and the first lens group is imaged from the object side. In turn, a negative lens component, a reflecting member, and a rear sub lens group having a first positive lens and a second positive lens, and the second lens group has a plurality of lenses including a negative lens. The rear lens group has at least three lens units having a positive refractive power, and satisfies the following conditional expressions (3), (4), and (AA).
−0.2 <f _2G / f _T <−0.05 (AA)
1.8 <Δ _2G / f _W <15 (4)
16.5 <| ν _dp1 −ν _dp2 | <80 (3)
here,
f _T is the focal length of the entire zoom lens system at the telephoto end,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
f _2G is the focal length of the second lens group,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, with the movement toward the image side being a positive sign,
ν _dp1 is the Abbe number based on the d-line of the first positive lens in the first lens group,
ν _dp2 is the Abbe number based on the d-line of the second positive lens in the first lens group,
And
The lens component is a lens body separated by a surface in contact with air at the lens effective surface, and is composed of a single lens or a cemented lens,
The Abbe number is (n _d1 −1) / (n _F1 −n _C1 ),
n _d1 , n _C1 , and n _F1 are the refractive indices of the d-line, C-line, and F-line of the first positive lens or the second positive lens,
It is.

In order to ensure the angle of view at the wide angle end, it is necessary to sufficiently secure the positive refractive power of the synthesis system of the third lens unit and subsequent lens units.
According to the second aspect, by including at least three lens units having positive refractive power in the rear lens group, the positive refractive power can be shared among the lens groups having positive refractive power, which is advantageous for ensuring performance. .

Conditional expression (4) is a condition for a preferable amount of movement of the second lens group for advantageous reduction in size while being advantageous in ensuring a zoom ratio and an angle of view.
By securing the amount of movement of the second lens group so as not to fall below the lower limit of conditional expression (4), the function of ensuring the angle of view by the retrofocus type of the entire zoom lens can be exhibited at the wide angle end.
In addition, it becomes easy to sufficiently secure the zooming function by the second lens group, and it is advantageous for reducing the aberration in the second lens group by suppressing the refractive power of the second lens group.
By limiting the amount of movement of the second lens group so as not to exceed the upper limit of conditional expression (4), the entrance pupil can be easily brought closer to the first lens group, and an increase in the effective diameter of the first lens group can be suppressed, Even if the angle of view is secured, it is advantageous for downsizing of the image pickup apparatus.

Conditional expression (3) specifies a preferable Abbe number difference between the first positive lens and the second positive lens in the first lens group.
In an optical system with high zoom ratio and reduced optical total length, the lateral chromatic aberration of the first lens group can be efficiently suppressed by ensuring the Abbe number difference so as not to fall below the lower limit of the conditional expression (3).
By not exceeding the upper limit of the conditional expression (3), it is possible to suppress a reduction in workability of the combined material and to be advantageous in terms of cost.
Other operations and effects are the same as those of the imaging device of the first aspect.

  In the imaging device of the second aspect of the present invention, the third lens group may have a positive refractive power, the fourth lens group may have a positive refractive power, and the fifth lens group may have a positive refractive power. preferable.

According to this configuration, when the zoom lens is a positive / negative / positive / positive / positive five-group zoom type, the second lens group can have a main zooming function.
In order to secure the angle of view at the wide-angle end, it is necessary to sufficiently secure the positive refracting power of the synthesis system of the third lens group and subsequent lens groups. Thus, the positive refractive power can be assigned to each lens group, which is advantageous for downsizing and ensuring performance by saving the number of lens groups.

  In the imaging device according to the first aspect of the present invention, the rear lens group preferably has at least three lens groups having a positive refractive power.

  It is preferable that the third lens group has a positive refractive power, the fourth lens group has a positive refractive power, and the fifth lens group has a positive refractive power.

Moreover, it is preferable that the following conditional expression (4) is satisfied.
1.8 <Δ _2G / f _W <15 (4)
here,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, with the movement toward the image side being a positive sign,
And
The lens component is a lens body that is delimited by a surface in contact with air on the lens effective surface, and is configured by a single lens or a cemented lens.

Furthermore, it is preferable that the following conditional expression (3) is satisfied.
16.5 <| ν _dp1 −ν _dp2 | <80 (3)
here,
ν _dp1 is the Abbe number based on the d-line of the first positive lens in the first lens group,
ν _dp2 is the Abbe number based on the d-line of the second positive lens in the first lens group,
And
The lens component is a lens body separated by a surface in contact with air at the lens effective surface, and is composed of a single lens or a cemented lens,
The Abbe number is (n _d1 −1) / (n _F1 −n _C1 ),
n _d1 , n _C1 , and n _F1 are the refractive indices of the d-line, C-line, and F-line of the first positive lens or the second positive lens,
It is.

  In the first and second aspects of the present invention, it is preferable to have a configuration that satisfies at least one of the following, and more than one.

It is preferable that the most object side lens in the second lens group satisfies the following conditional expression (B).
N _dn1 ≧ 1.60 (B)
here,
N _dn1 is the refractive index of the d-line of the negative lens closest to the object among the plurality of lenses in the second lens group.

  By ensuring the refractive index so as not to fall below the lower limit of conditional expression (B), the absolute value of curvature can be reduced, which is advantageous for correcting various aberrations (particularly off-axis aberrations near the wide-angle end).

The second lens group includes a single lens composed of a first negative lens and a cemented lens composed of a second negative lens and a positive lens, and the image side surfaces of both the first negative lens and the second negative lens are both on the image side. It is preferable to satisfy the following conditional expression (C).
2.0 <SF _2G <30.0 (C)
here,
SF _2G = | (R ₁ + R ₂ ) / (R ₁ −R 2) |
R ₁ is a paraxial radius of curvature on the image plane side of the first negative lens,
R ₂ is the paraxial radius of curvature of the image side surface of the second negative lens in the cemented lens,
It is.

By avoiding falling below the lower limit of conditional expression (C), the curvature of the first negative lens image side surface is secured, the curvature of the image side surface of the second negative lens is suppressed, and the refractive power of the second negative lens is prevented from being excessive. Various aberrations and longitudinal chromatic aberration can easily reduce overcorrection.
By not exceeding the upper limit of conditional expression (C), the first negative lens image side curvature is suppressed, the second negative lens image side curvature is secured, and the refractive power of the second negative lens is appropriately secured. In addition, various aberrations and longitudinal chromatic aberration can be easily corrected.

The most object-side negative lens in the second lens group preferably has an aspheric lens surface.
This is advantageous for both securing the paraxial negative refractive power and correcting off-axis aberrations such as coma at the wide-angle end.

Moreover, it is preferable that the following conditional expression (D) is satisfied.
1.0 <L _T / f _T <2.0 (D)
here,
L _T is the distance from the entrance surface of the zoom lens at the telephoto end to the image plane is obtained by calculating the back focus as an air-equivalent length.

By making it not fall below the lower limit of conditional expression (D), it is possible to suppress excessive refractive power of each lens unit, which is advantageous in reducing aberrations.
By not exceeding the upper limit of the conditional expression (D), the imaging apparatus can be reduced in size.

The second lens group preferably satisfies the following conditional expression (E).
0.05 <Δ _2G / f _T <0.4 (E)
here,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, with the movement toward the image side being a positive sign.

By making sure that the lower limit of conditional expression (E) is not exceeded, the refractive power of the second lens group for securing the zoom ratio can be suppressed, which is advantageous in correcting various aberrations.
By avoiding exceeding the upper limit of conditional expression (E), the amount of movement of the second lens group is suppressed, which is advantageous for shortening the overall length.

The second lens group preferably satisfies the following conditional expression (F).
0.5 <Σ _2G / f _W <1.0 (F)
here,
Σ _2G is the thickness of the second lens group on the optical axis,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
It is.

By ensuring the thickness of the second lens group so as not to fall below the lower limit of conditional expression (F), the number of lenses and the air lens in the second lens group can be secured, which is advantageous for correcting various aberrations.
By suppressing the thickness of the second lens group so as not to exceed the upper limit of conditional expression (F), it becomes easy to secure a moving space for the second lens group.

The aperture stop is preferably fixed at the time of zooming from the wide angle end to the telephoto end.
This configuration is advantageous for miniaturization by simplifying the mechanical mechanism and eliminating the dead space required to move the diaphragm.

The third lens group preferably has a positive refractive power, and the third lens group and the aperture stop are preferably fixed when zooming from the wide-angle end to the telephoto end.
As a result, the mechanical mechanism is simplified, and the light beam height of the movable group after the aperture stop is suppressed, which is advantageous in achieving both a high zoom ratio and a reduction in size.

  The third lens group has a positive refractive power, the fourth lens group has a positive refractive power, the fifth lens group has a negative refractive power, and has a positive refractive power on the image side of the fifth lens group. It is preferable to arrange a sixth lens group having

  In this way, by making the zoom lens a zoom type including positive, negative, positive, positive, negative, and positive from the object side, by inserting the negative lens group into the rear lens group, the third lens group and the fourth lens group. This is advantageous in reducing the thickness of the optical system. It is also advantageous for field curvature correction. Furthermore, focusing with the fifth lens group leads to miniaturization of the optical system.

Of the first positive lens and the second positive lens, either one of the positive lenses preferably satisfies the following conditional expression (5A), and the other positive lens preferably satisfies the following conditional expression (5B). .
ν _dpone > 60 (5A)
ν _dpoth <60 (5B)
here,
ν _dpone is the d-line reference Abbe number of one of the first positive lens and the second positive lens,
ν _dpoth is the Abbe number of the other d-line reference of the first positive lens and the second positive lens,
It is.

  In this configuration, in an optical system with a high zoom ratio and a reduced optical total length, the first and second lens materials having positive refractive power are selected so that the above conditional expressions (5A) and (5B) are satisfied simultaneously. Thus, a positive lens having a large partial dispersion ratio is used for one positive lens, and the lateral chromatic aberration generated in the first positive lens of the first lens group can be efficiently suppressed while suppressing the secondary spectrum.

In addition, it is preferable that the difference in refractive index between the first positive lens and the second positive lens satisfies the conditional expression (A).
0.1 <n _dp1 −n _dp2 <0.65 (A)
here,
n _dp1 is the d-line reference refractive index of one of the first positive lens and the second positive lens,
n _dp2 is the d-line reference refractive index of the other of the first positive lens and the second positive lens,
The refractive index based on the d-line of the positive lens with the smaller Abbe number is n _dp1 ,
It is.

By ensuring the difference in refractive index so that it does not fall below the lower limit of conditional expression (A), the chromatic aberration is corrected with the lens with the larger Abbe number, and the refractive power that is advantageous for increasing the zoom ratio with the other lens It becomes easy to secure.
By making it not exceed the upper limit of conditional expression (A), it becomes easy to suppress the high cost of the material.

  Furthermore, the third lens group and the fourth lens group have positive refractive power, and when changing the magnification from the wide angle end to the telephoto end, the aperture stop and the third lens group are fixed, and the fourth lens group is fixed. It is preferable to move in the optical axis direction.

  By making the third lens group have positive refracting power, the effective diameter of the fourth lens group can be easily reduced, leading to a reduction in diameter (thinner imaging device). Further, by moving the fourth lens group in the optical axis direction, a zooming function or an image plane position adjusting function can be provided.

  It is preferable that the fifth lens group has a positive refractive power and is fixed when zooming from the wide-angle end to the telephoto end.

  By setting the fifth lens group to have positive refractive power, the exit pupil can be easily separated from the image plane, and the influence of shading can be easily reduced. In addition, by fixing the fifth lens group, the number of movable lens groups in the rear lens group can be reduced, leading to a simplified configuration.

  The fifth lens group has a negative refractive power, and a sixth lens group having a positive refractive power is arranged on the image side of the fifth lens group, and the fifth lens group at the time of zooming from the wide angle end to the telephoto end It is preferable that the distance between the first lens group and the sixth lens group is changed, and the fifth lens group is moved during focusing.

  Accordingly, by inserting a negative lens group in the rear lens group, the effective diameters of the third lens group and the fourth lens group can be reduced, which is advantageous in reducing the thickness of the optical system. It is also advantageous for field curvature correction. Furthermore, focusing with the fifth lens group leads to miniaturization of the optical system.

It is preferable that the fourth lens group satisfies the following conditional expression (6).
0.1 <f _4G / f _T <0.6 (6)
here,
f _4G is the focal length of the fourth lens group,
f _T is the focal length of the entire zoom lens system at the telephoto end,
It is.

Conditional expression (6) specifies a preferable focal length of the fourth lens unit having a positive refractive power.
By making sure that the lower limit of conditional expression (6) is not exceeded, excess of the refractive power of the fourth lens unit is suppressed, which is advantageous for aberration reduction.
By not exceeding the upper limit of conditional expression (6), the amount of movement for zooming of the fourth lens group can be reduced, which is advantageous for achieving both a high zoom ratio and compactness.

It is preferable that the most image side lens unit in the zoom lens satisfies the following conditional expression (7).
0.1 <f _RG / f _T <0.8 (7)
f _RG is the focal length of the lens group closest to the image side in the zoom lens,
f _T is the focal length of the entire zoom lens system at the telephoto end,
It is.

Conditional expression (7) specifies a preferable focal length of the lens group closest to the image side.
By making sure that the lower limit of conditional expression (7) is not exceeded, excessive refractive power of the lens unit closest to the image side is suppressed, which is advantageous in reducing aberrations.
By not exceeding the upper limit of conditional expression (7), the positive refracting power of the lens group closest to the image side is sufficiently secured, the exit pupil is easily separated from the image plane, and shading is easily reduced.

In addition, it is preferable to include an image conversion unit that converts an electrical signal output from the image sensor and including distortion by the zoom lens into an image signal in which distortion is corrected by image processing.
Thereby, distortion correction can be relaxed, and one negative lens component closer to the object side than the reflecting surface and further one negative lens can be formed, which is advantageous in reducing the thickness of the imaging apparatus.

  Here, it is more preferable that each of the above-described configurations satisfy a plurality at the same time.

  For conditional expression (1), it is more preferable to set the lower limit value to 7.5, more preferably 8 to 9, and so on. More preferably, the upper limit value is 24, more preferably 12.

  For conditional expression (2), it is more preferable to set the lower limit value to 0.6, further 0.7, and 1.0. More preferably, the upper limit value is 1.37, more preferably 1.36.

  For conditional expression (3), it is more preferable that the lower limit value be 20, more preferably 22 or even 24. More preferably, the upper limit value is 65, more preferably 60 or 45.

  For conditional expression (4), it is more preferable to set the lower limit to 1.85, more preferably 1.9, and even 1.95. More preferably, the upper limit value is 13, more preferably 10 or 5.

  For conditional expression (5A), it is more preferable to set the lower limit value to 65, more preferably 70.

  For conditional expression (5B), it is more preferable to set the upper limit value to 55, more preferably 50.

  For conditional expression (6), it is more preferable to set the lower limit value to 0.2, more preferably 0.25. More preferably, the upper limit value is 0.45, more preferably 0.33.

  For conditional expression (7), it is more preferable to let the lower limit value to be 0.15, further 0.2. The upper limit value is more preferably 0.7, and even more preferably 0.6.

  For conditional expression (A), the lower limit value is more preferably 0.15, and even more preferably 0.2. More preferably, the upper limit value is 0.5, more preferably 0.4.

  For conditional expression (AA), it is more preferable to let the lower limit value to be −0.19, more preferably −0.18. More preferably, the upper limit value is -0.06, more preferably -0.08.

  For conditional expression (B), it is more preferable to set the lower limit value to 1.65, more preferably 1.70. From the viewpoint of material cost, it is more preferable to set an upper limit value so as not to exceed 2.7, and further 2.5.

  For conditional expression (C), the lower limit value is more preferably 2.5, and even more preferably 3.0. More preferably, the upper limit value is 28.0, more preferably 25.0.

  For conditional expression (D), it is more preferable to set the lower limit value to 1.1, further 1.2. More preferably, the upper limit value is 1.9, more preferably 1.8.

  For conditional expression (E), it is more preferable to set the lower limit value to 0.1, further 0.15. More preferably, the upper limit value is 0.35, more preferably 0.32.

  For conditional expression (F), the lower limit value is more preferably 0.55, and even more preferably 0.6. More preferably, the upper limit value is 0.98, more preferably 0.94.

  The image pickup apparatus according to the present invention has an effect of providing an image pickup apparatus including a zoom lens that is advantageous for shortening the overall length while securing a zoom ratio and a field angle at the wide-angle end. Furthermore, there is an effect that it is possible to provide an imaging apparatus including a zoom lens that is advantageous for both shortening the overall length and ensuring optical performance.

FIG. 2 is a lens cross-sectional view at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity according to the first exemplary embodiment of the zoom lens of the present invention. FIG. 5 is a lens cross-sectional view at a wide angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to a second embodiment of the zoom lens of the present invention. FIG. 6 is a lens cross-sectional view at a wide angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to a third embodiment of the zoom lens of the present invention. FIG. 6 is a lens cross-sectional view at a wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Embodiment 4 of the zoom lens of the present invention. FIG. 6 is a lens cross-sectional view at a wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Example 5 of the zoom lens of the present invention. FIG. 10 is a lens cross-sectional view at a wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Example 6 of the zoom lens of the present invention. FIG. 10 is a lens cross-sectional view at a wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Example 7 of the zoom lens of the present invention. FIG. 6 is an aberration diagram for Example 1 upon focusing on an object point at infinity. FIG. 6 is an aberration diagram for Example 2 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 3 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 4 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 5 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 6 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 7 upon focusing on an object point at infinity. It is a figure explaining correction | amendment of a distortion aberration. It is a front perspective view which shows the external appearance of the digital camera incorporating the optical path bending zoom lens by this invention. It is a rear perspective view of the digital camera. It is sectional drawing of the said digital camera. It is a block diagram of the internal circuit of the main part of the digital camera.

  Embodiments of an imaging apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  Examples 1 to 7 of the zoom lens according to the present invention will be described below. FIGS. 1 to 7 show lens cross-sectional views of the wide-angle end (a), the intermediate focal length state (b), and the telephoto end (c) when focusing on an object point at infinity in Examples 1 to 7, respectively. 1 to 7, the first lens group is G1, the second lens group is G2, the third lens group is G3, the fourth lens group is G4, the fifth lens group is G5, the sixth lens group is G6, and the brightness is high. The aperture (aperture) is indicated by S, the parallel plate constituting the low-pass filter provided with the wavelength band limiting coat for limiting infrared light is indicated by F, the parallel plate of the cover glass of the electronic image sensor is indicated by C, and the image plane is indicated by I. is there. In addition, you may give the multilayer film for a wavelength range restriction | limiting to the surface of the cover glass C. FIG. Further, the cover glass C may have a low-pass filter action. The parallel plate F may not have the function of a low bass filter.

  In each embodiment, the position of the aperture stop S is fixed. All of the numerical data is data in a state where an object at infinity is focused. The unit of length of each numerical value is mm, and the unit of angle is ° (degree). Focusing is performed by moving the fourth lens group G4 in Examples 1 to 3, and is performed by moving the fifth lens group G5 in Examples 4 to 7. Further, the zoom data are values at the wide-angle end (WE), the intermediate zoom state (ST) defined in the present invention, and the telephoto end (TE).

  As shown in FIG. 1, the zoom lens of Example 1 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. A three-lens group G3, an aperture stop S, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are arranged.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the object side. The fifth lens group G5 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a biconvex positive lens, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconvex positive lens and a biconcave negative lens. The third lens group G3 is composed of a biconvex positive lens. The fourth lens group G4 includes a cemented lens which is formed by a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side. The fifth lens group G5 includes a cemented lens of a negative meniscus lens having a convex surface directed toward the object side and a positive meniscus lens having a convex surface directed toward the object side, a negative meniscus lens having a convex surface directed toward the object side, and a biconvex positive lens. And a cemented lens. 1 to 7 are developed views with the reflection surface in the prism omitted, but in reality, a right angle prism is used as shown in FIG.

  The aspherical surface includes both surfaces of the object side biconvex positive lens of the first lens group G1, the object side surface of the image side biconvex positive lens, and both surfaces of the object side biconcave negative lens of the second lens group G2. The biconvex positive lens of the third lens group G3 and the object side surface of the biconvex positive lens of the fourth lens group G4 are provided on eight surfaces.

  As shown in FIG. 2, the zoom lens according to the second embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. A three-lens group G3, an aperture stop S, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are arranged.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the object side. The fifth lens group G5 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a positive meniscus lens having a convex surface directed toward the image side, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconvex positive lens and a biconcave negative lens. The third lens group G3 is composed of a biconvex positive lens. The fourth lens group G4 includes a cemented lens which is formed by a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side. The fifth lens group G5 includes a cemented lens of a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side, and a cemented lens of a negative meniscus lens having a convex surface facing the object side and a biconvex positive lens. Become.

  The aspheric surfaces include both surfaces of the positive meniscus lens of the first lens group G1, the object side surface of the biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens group G3. The two surfaces of the biconvex positive lens and the object side surface of the biconvex positive lens of the fourth lens group G4 are provided on eight surfaces.

  As shown in FIG. 3, the zoom lens of Example 3 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. A three-lens group G3, an aperture stop S, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power are arranged.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the object side. The fifth lens group G5 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a positive meniscus lens having a convex surface directed toward the image side, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconvex positive lens and a biconcave negative lens. The third lens group G3 is composed of a biconvex positive lens. The fourth lens group G4 includes a cemented lens which is formed by a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side. The fifth lens group G5 includes a cemented lens of a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side, and a cemented lens of a negative meniscus lens having a convex surface facing the object side and a biconvex positive lens. Become.

  The aspheric surfaces include both surfaces of the positive meniscus lens of the first lens group G1, the object side surface of the biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens group G3. The two surfaces of the biconvex positive lens and the object side surface of the biconvex positive lens of the fourth lens group G4 are provided on eight surfaces.

  As shown in FIG. 4, the zoom lens of Example 4 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power are disposed. is doing.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the image side after moving to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a biconvex positive lens, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconcave negative lens and a biconvex positive lens. The third lens group G3 is composed of a positive meniscus lens having a convex surface directed toward the object side. The fourth lens group G4 includes a cemented lens of a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side, and a biconvex positive lens. The fifth lens group G5 is composed of a negative meniscus lens having a convex surface directed toward the object side. The sixth lens group G6 is composed of a biconvex positive lens.

  The aspherical surface includes both the image side surface of the negative meniscus lens of the first lens group G1, both surfaces of the object side biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens. It is provided on eight surfaces, that is, the object-side surface of the positive meniscus lens of the group G3 and both surfaces of the biconvex positive lens on the image side of the fourth lens group G4.

  As shown in FIG. 5, the zoom lens of Example 5 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power are disposed. is doing.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the image side after moving to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a biconvex positive lens, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconcave negative lens and a biconvex positive lens. The third lens group G3 is composed of a positive meniscus lens having a convex surface directed toward the object side. The fourth lens group G4 includes a cemented lens of a biconvex positive lens and a biconcave negative lens, and a biconvex positive lens. The fifth lens group G5 is composed of a negative meniscus lens having a convex surface directed toward the object side. The sixth lens group G6 is composed of a biconvex positive lens.

  The aspherical surface includes both the image side surface of the negative meniscus lens of the first lens group G1, both surfaces of the object side biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens. It is provided on eight surfaces, that is, the object-side surface of the positive meniscus lens of the group G3 and both surfaces of the biconvex positive lens on the image side of the fourth lens group G4.

  As shown in FIG. 6, the zoom lens of Example 6 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power are disposed. is doing.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a biconvex positive lens, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconcave negative lens and a biconvex positive lens. The third lens group G3 is composed of a positive meniscus lens having a convex surface directed toward the object side. The fourth lens group G4 includes a cemented lens of a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side, and a biconvex positive lens. The fifth lens group G5 is composed of a negative meniscus lens having a convex surface directed toward the object side. The sixth lens group G6 is composed of a biconvex positive lens.

  The aspherical surface includes both the image side surface of the negative meniscus lens of the first lens group G1, both surfaces of the object side biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens. It is provided on eight surfaces, that is, the object-side surface of the positive meniscus lens of the group G3 and both surfaces of the biconvex positive lens on the image side of the fourth lens group G4.

  As shown in FIG. 7, the zoom lens of Example 7 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop S, A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power are disposed. is doing.

  At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed. The second lens group G2 moves to the image side. The third lens group G3 is fixed. The fourth lens group G4 moves to the object side. The fifth lens group G5 moves to the object side. The sixth lens group G6 is fixed.

  In order from the object side, the first lens group G1 includes a negative meniscus lens having a convex surface directed toward the object side, a prism, a biconvex positive lens, and a biconvex positive lens. The second lens group G2 includes a biconcave negative lens and a cemented lens made up of a biconcave negative lens and a biconvex positive lens. The third lens group G3 is composed of a positive meniscus lens having a convex surface directed toward the object side. The fourth lens group G4 includes a cemented lens of a biconvex positive lens and a biconcave negative lens, and a biconvex positive lens. The fifth lens group G5 is composed of a negative meniscus lens having a convex surface directed toward the object side. The sixth lens group G6 is composed of a biconvex positive lens.

  The aspherical surface includes both the image side surface of the negative meniscus lens of the first lens group G1, both surfaces of the object side biconvex positive lens, both surfaces of the object side biconcave negative lens of the second lens group G2, and the third lens. It is provided on eight surfaces, that is, the object-side surface of the positive meniscus lens of the group G3 and both surfaces of the biconvex positive lens on the image side of the fourth lens group G4.

  Below, the numerical data of each said Example are shown. Symbols are the above, BF is back focus, f1, f2... Are focal lengths of each lens group, FNO is F number, ω is half angle of view, WE is wide angle end, ST is intermediate focal length state, TE is telephoto end , R is the radius of curvature of each lens surface, d is the spacing between the lens surfaces, nd is the refractive index of the d-line of each lens, and νd is the Abbe number of each lens. The total lens length described later is obtained by adding back focus to the distance from the lens front surface to the lens final surface. BF (back focus) represents the distance from the last lens surface to the paraxial image plane in terms of air.

Each aspheric shape is expressed by the following formula (I) using each aspheric coefficient in each embodiment.
However, the coordinate in the optical axis direction is Z, and the coordinate in the direction perpendicular to the optical axis is Y.
^{Z = (Y 2 / r)} / [1+ {1- (1 + K) · (Y / r) 2} 1/2] + A 4 × Y 4 + A 6 × Y 6 + A 8 × Y 8 + A 10 × Y 10 + A ₁₂ x Y ¹² (I)
here,
r is the paraxial radius of curvature,
K is the cone coefficient,
A4, A6, A8, A10, and A12 are fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order aspheric coefficients, respectively.
In the aspheric coefficient, “e−n” (n is an integer) indicates “10 ⁻ⁿ ”.

Numerical example 1
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 98.092 0.50 2.00069 25.46
2 14.641 2.60
3 ∞ 12.00 1.90366 31.32
4 ∞ 0.21
5 * 443.612 1.66 1.74320 49.34
6 * -24.098 0.20
7 * 15.703 2.85 1.49700 81.54
8 -38.559 Variable
9 * -8.106 0.30 1.90200 25.10
10 * 9.383 0.50
11 15.787 2.10 1.94595 17.98
12 -7.628 0.30 1.88300 40.76
13 17.076 Variable
14 * 9.821 1.60 1.61881 63.85
15 * -85.122 0.20
16 (Aperture) ∞ Variable
17 * 14.967 3.17 1.49700 81.54
18 -5.729 0.30 1.85026 32.27
19 -9.050 Variable
20 38631.547 0.30 2.00069 25.46
21 4.131 2.73 1.51633 64.14
22 2427.864 5.51
23 191677.874 0.30 1.78800 47.37
24 15.097 2.47 2.00178 19.32
25 -15.327 0.20
26 ∞ 0.50 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51680 64.20
29 ∞ 0.37
Image plane ∞

Aspheric data 5th surface
K = 0.000
A4 = -2.25479e-08, A6 = 6.41668e-08, A8 = 4.95792e-10
6th page
K = 0.000
A4 = -5.33163e-06, A6 = -4.27108e-08, A8 = 7.27512e-10
7th page
K = 0.000
A4 = -1.87524e-05, A6 = -1.73513e-07, A8 = -1.25910e-10
9th page
K = -0.057
A4 = 8.81519e-04, A6 = 2.11573e-05, A8 = -1.27622e-06
10th page
K = 0.000
A4 = -1.49369e-04, A6 = 3.61056e-05, A8 = -1.63559e-06
14th page
K = 1.844
A4 = -4.00279e-04, A6 = -9.91698e-06, A8 = 1.10163e-07
15th page
K = 3.153
A4 = 2.65249e-05, A6 = -6.76979e-06, A8 = 3.90433e-07
17th page
K = -2.246
A4 = -1.89961e-04, A6 = 8.77333e-08, A8 = 2.68828e-07

Zoom data
WE ST TE
Focal length 5.14 15.64 48.86
FNO. 3.91 5.70 6.83
Angle of view 2ω 81.42 26.14 8.45
Image height 3.84 3.84 3.84
BF 1.72 1.72 1.72
Total length 68.79 68.79 68.79

d8 1.00 9.52 15.55
d13 15.07 6.54 0.50
d16 7.09 3.01 2.64
d19 4.12 8.10 8.53

Group focal length
f1 = 15.99 f2 = -5.04 f3 = 14.32 f4 = 15.73 f5 = 25.49

Numerical example 2
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 85.127 0.50 2.00069 25.46
2 14.313 2.60
3 ∞ 12.00 1.90366 31.32
4 ∞ 0.21
5 * -225.691 1.59 1.74320 49.34
6 * -21.762 0.20
7 * 14.439 2.90 1.49700 81.54
8 -44.212 variable
9 * -8.110 0.30 1.90200 25.10
10 * 9.442 0.50
11 13.990 2.16 1.94595 17.98
12 -7.826 0.30 1.88300 40.76
13 14.833 Variable
14 * 10.087 1.60 1.61881 63.85
15 * -62.720 0.20
16 (Aperture) ∞ Variable
17 * 15.018 3.03 1.49700 81.54
18 -5.518 0.30 1.85026 32.27
19 -8.771 Variable
20 -90.962 0.30 2.00069 25.46
21 4.387 2.74 1.51633 64.14
22 55.476 5.55
23 27.971 0.30 1.78800 47.37
24 13.293 2.45 2.00178 19.32
25 -21.675 0.20
26 ∞ 0.50 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51680 64.20
29 ∞ 0.37
Image plane ∞

Aspheric data 5th surface
K = 0.000
A4 = 5.06395e-06, A6 = 7.51622e-08, A8 = 1.38532e-09, A10 = -6.90374e-12
6th page
K = 0.000
A4 = -6.23781e-06, A6 = -3.50013e-08, A8 = 1.35599e-09, A10 = -1.27928e-24
7th page
K = 0.000
A4 = -2.62339e-05, A6 = -1.83640e-07, A8 = 1.11207e-13, A10 = 7.84124e-26
9th page
K = -0.059
A4 = 7.50130e-04, A6 = 1.44278e-05, A8 = -5.98152e-07, A10 = -9.09258e-26
10th page
K = 0.000
A4 = -2.11408e-04, A6 = 2.12777e-05, A8 = -3.47033e-07, A10 = -3.68350e-25
14th page
K = 1.852
A4 = -3.47949e-04, A6 = -7.39738e-06, A8 = 1.51684e-07, A10 = 1.93639e-26
15th page
K = 2.759
A4 = 6.04137e-05, A6 = -4.24405e-06, A8 = 3.64538e-07, A10 = 2.56493e-26
17th page
K = -2.277
A4 = -1.63104e-04, A6 = 1.89728e-07, A8 = 3.17801e-07, A10 = -5.84793e-25

Zoom data
WE ST TE
Focal length 5.13 15.62 49.01
FNO. 3.89 5.69 6.81
Angle of view 2ω 81.44 26.06 8.38
Image height 3.84 3.84 3.84
BF 1.73 1.73 1.73
Total length 68.68 68.68 68.68

d8 1.00 9.50 15.56
d13 15.05 6.54 0.50
d16 6.98 3.23 2.60
d19 4.20 8.11 8.56

Group focal length
f1 = 16.02 f2 = -5.02 f3 = 14.16 f4 = 15.57 f5 = 20.97

Numerical Example 3
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 107.329 0.50 2.00069 25.46
2 14.826 2.60
3 ∞ 12.00 1.90366 31.32
4 ∞ 0.21
5 * -449.056 1.55 1.74320 49.34
6 * -22.336 0.20
7 * 14.704 2.87 1.49700 81.54
8 -44.795 Variable
9 * -8.069 0.30 1.90200 25.10
10 * 9.666 0.50
11 13.977 2.16 1.94595 17.98
12 -7.846 0.30 1.88300 40.76
13 14.431 Variable
14 * 10.137 1.59 1.61881 63.85
15 * -55.149 0.20
16 (Aperture) ∞ Variable
17 * 13.351 3.35 1.49700 81.54
18 -5.277 0.30 1.85026 32.27
19 -8.601 Variable
20 -130.342 0.30 2.00069 25.46
21 3.992 2.56 1.51633 64.14
22 16.428 5.20
23 19.267 0.30 1.78800 47.37
24 9.139 3.15 2.00069 25.46
25 -19.671 0.20
26 ∞ 0.50 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51680 64.20
29 ∞ 0.37
Image plane ∞

Aspheric data 5th surface
K = 0.000
A4 = 5.04644e-06, A6 = 6.41121e-08, A8 = 1.46460e-09, A10 = 4.38213e-11
6th page
K = 0.000
A4 = -4.03123e-06, A6 = -3.70975e-08, A8 = 7.18165e-10, A10 = 5.94905e-11
7th page
K = 0.000
A4 = -2.30009e-05, A6 = -1.89066e-07, A8 = -2.83481e-12
9th page
K = -1.391
A4 = 6.24893e-04, A6 = -8.62204e-06, A8 = 5.61043e-07
10th page
K = 0.000
A4 = -1.13346e-06, A6 = -6.89849e-06, A8 = 1.62345e-06
14th page
K = 1.954
A4 = -4.17674e-04, A6 = -9.55420e-06, A8 = 2.86015e-07
15th page
K = 20.082
A4 = 5.90407e-06, A6 = -6.36510e-06, A8 = 5.36924e-07
17th page
K = 0.570
A4 = -2.75049e-04, A6 = 2.77954e-06, A8 = 3.64844e-07

Zoom data
WE ST TE
Focal length 5.12 15.41 48.95
FNO. 3.90 5.98 6.80
Angle of view 2ω 81.45 26.28 8.35
Image height 3.84 3.84 3.84
BF 1.73 1.73 1.73
Total length 68.68 68.68 68.68

d8 1.00 9.49 15.61
d13 15.11 6.61 0.50
d16 6.74 3.21 2.61
d19 3.97 7.59 8.14

Group focal length
f1 = 16.11 f2 = -5.02 f3 = 13.97 f4 = 14.96 f5 = 13.04

Numerical Example 4
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 99.518 0.60 1.84666 23.78
2 * 11.428 2.70
3 ∞ 11.97 1.84666 23.78
4 ∞ 0.20
5 * 19.605 3.00 1.49700 81.54
6 * -15.158 0.20
7 38.855 2.30 1.72916 54.68
8 -38.503 Variable
9 * -13.098 0.40 1.80139 45.45
10 * 6.964 1.48
11 -14.105 0.50 2.01820 28.03
12 9.045 1.72 1.94362 17.55
13 -14.750 Variable
14 (Aperture) ∞ 0.90
15 * 6.851 1.45 1.49700 81.54
16 15.699 Variable
17 125.536 3.83 1.49700 81.54
18 -9.420 0.50 1.99165 26.93
19 -40.393 0.20
20 * 21.383 2.60 1.53180 56.00
21 * -7.973 variable
22 14.105 1.10 1.90259 32.50
23 5.168 Variable
24 11.884 2.83 1.49700 81.60
25 -11.931 0.15
26 ∞ 0.42 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51633 64.10
Image plane ∞

Aspheric data 2nd surface
K = -4.467
A4 = 4.03959e-04, A6 = -1.70441e-06, A8 = 1.72129e-08
5th page
K = -3.000
A4 = -8.21321e-05, A6 = 9.69689e-07, A8 = -1.25272e-08
6th page
K = 1.464
A4 = 3.35955e-05, A6 = 9.19573e-07, A8 = -4.97736e-09
9th page
K = 0.000
A4 = 2.86004e-04
10th page
K = 0.000
A4 = -7.24011e-04, A6 = 3.64235e-06
15th page
K = 0.000
A4 = -3.34590e-04, A6 = -4.78611e-06
20th page
K = 0.000
A4 = -4.11171e-04
21st page
K = 0.000
A4 = 2.42732e-04

Zoom data
WE ST TE
Focal length 4.52 20.66 47.51
FNO. 4.19 5.80 6.84
Angle of view 2ω 86.13 18.74 8.33
Statue height 3.59 3.59 3.59
BF 1.25 1.25 1.25
Total length 69.31 69.31 69.31

d8 0.50 8.37 11.51
d13 12.01 4.14 1.00
d16 4.36 0.35 1.80
d21 9.56 9.04 1.98
d23 3.13 7.67 13.28

Group focal length
f1 = 11.03 f2 = -5.58 f3 = 23.20 f4 = 14.58 f5 = -9.60 f6 = 12.47

Numerical Example 5
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 106.398 0.60 1.84666 23.78
2 * 11.375 2.73
3 ∞ 11.97 1.84666 23.78
4 ∞ 0.20
5 * 17.538 3.10 1.49700 81.54
6 * -16.212 0.20
7 54.024 2.20 1.72916 54.68
8 -31.666 variable
9 * -15.838 0.40 1.76802 49.24
10 * 6.324 1.30
11 -44.612 0.50 1.88300 40.76
12 9.045 1.72 1.94595 17.98
13 -253.761 Variable
14 (Aperture) ∞ 0.60
15 * 8.848 1.45 1.58313 59.38
16 20.952 Variable
17 17.087 2.92 1.49700 81.54
18 -9.420 0.50 1.90366 31.32
19 45.271 0.20
20 * 15.563 2.60 1.53180 56.00
21 * -7.160 variable
22 24.424 1.10 1.90259 32.50
23 6.259 Variable
24 10.011 2.83 1.53071 55.60
25 -21.389 0.15
26 ∞ 0.42 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51633 64.10
Image plane ∞

Aspheric data 2nd surface
K = -4.467
A4 = 3.98813e-04, A6 = -1.95950e-06, A8 = 2.03574e-08
5th page
K = -3.000
A4 = -6.56079e-05, A6 = 2.46571e-07, A8 = -1.38942e-09
6th page
K = 0.972
A4 = 2.46615e-05, A6 = 1.53622e-07, A8 = 2.91381e-10
9th page
K = 0.000
A4 = 3.25830e-05
10th page
K = 0.000
A4 = -7.11565e-04, A6 = -1.51397e-05
15th page
K = 0.000
A4 = -1.68543e-04, A6 = -5.03020e-06
20th page
K = 0.000
A4 = -4.30833e-04
21st page
K = 0.000
A4 = 3.32580e-04

Zoom data
WE ST TE
Focal length 4.51 20.64 47.47
FNO. 4.06 6.43 6.91
Angle of view 2ω 87.46 18.74 8.24
Statue height 3.59 3.59 3.59
BF 1.28 1.28 1.28
Total length 68.79 68.79 68.79

d8 0.50 8.06 11.51
d13 12.01 4.45 1.00
d16 5.57 0.72 1.81
d21 9.20 9.11 2.00
d23 3.10 8.05 14.08


Group focal length
f1 = 11.16 f2 = -5.51 f3 = 25.16 f4 = 13.79 f5 = -9.60 f6 = 13.26

Numerical Example 6
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 95.870 0.60 1.84666 23.78
2 * 11.718 2.70
3 ∞ 11.97 1.84666 23.78
4 ∞ 0.20
5 * 24.671 3.00 1.49700 81.54
6 * -13.769 0.20
7 24.896 2.30 1.72916 54.68
8 -58.694 variable
9 * -62.598 0.40 1.80139 45.45
10 * 6.068 1.48
11 -8.720 0.50 2.02000 28.00
12 9.045 1.72 1.95288 17.45
13 -13.268 Variable
14 (Aperture) ∞ 0.90
15 * 6.302 1.45 1.49700 81.54
16 13.705 Variable
17 91.032 3.83 1.49700 81.54
18 -9.420 0.50 1.99165 26.93
19 -48.897 0.20
20 * 20.939 2.60 1.53180 56.00
21 * -7.664 variable
22 12.911 1.10 1.90259 32.50
23 4.975 Variable
24 24.904 2.83 1.49700 81.60
25 -9.349 0.15
26 ∞ 0.42 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51633 64.10
Image plane ∞

Aspheric data 2nd surface
K = -4.467
A4 = 4.11404e-04, A6 = -9.95647e-07, A8 = 1.89726e-08
5th page
K = -3.000
A4 = -9.32001e-05, A6 = 7.68664e-07, A8 = -6.42927e-09
6th page
K = 0.720
A4 = 5.61993e-06, A6 = 5.31953e-07, A8 = -2.22711e-09
9th page
K = 0.000
A4 = -2.40110e-04
10th page
K = 0.000
A4 = -7.72857e-04, A6 = -2.31059e-05
15th page
K = 0.000
A4 = -4.20856e-04-7.81582e-06
20th page
K = 0.000
A4 = -5.03001e-04
21st page
K = 0.000
A4 = 2.36467e-04

Zoom data
WE ST TE
Focal length 4.88 20.61 46.95
FNO. 4.07 5.55 6.67
Angle of view 2ω 80.91 18.95 8.69
Statue height 3.59 3.59 3.59
BF 1.60 1.60 1.60
Total length 67.56 67.56 67.56

d8 0.50 7.41 10.17
d13 10.67 3.76 1.00
d16 4.28 1.10 1.00
d21 10.04 9.04 1.90
d23 1.98 6.17 13.41


Group focal length
f1 = 10.43 f2 = -5.38 f3 = 22.04 f4 = 14.48 f5 = -9.60 f6 = 14.06

Numerical Example 7
Unit mm

Surface data surface number rd nd νd
Object ∞ ∞
1 85.461 0.60 1.84666 23.78
2 * 11.377 2.73
3 ∞ 11.97 1.84666 23.78
4 ∞ 0.20
5 * 23.539 3.10 1.49700 81.54
6 * -13.680 0.20
7 31.645 2.20 1.72916 54.68
8 -43.456 variable
9 * -36.322 0.40 1.76802 49.24
10 * 6.213 1.30
11 -19.855 0.50 1.88300 40.76
12 9.045 1.72 1.94595 17.98
13 -1052.890 Variable
14 (Aperture) ∞ 0.60
15 * 6.699 1.45 1.58313 59.38
16 13.095 Variable
17 17.970 2.92 1.49700 81.54
18 -9.420 0.50 1.90366 31.32
19 52.493 0.20
20 * 13.725 2.60 1.53180 56.00
21 * -7.699 variable
22 15.744 1.10 1.90259 32.50
23 5.403 Variable
24 23.086 2.83 1.53071 55.60
25 -10.770 0.15
26 ∞ 0.42 1.54880 67.00
27 ∞ 0.50
28 ∞ 0.50 1.51633 64.10
Image plane ∞

Aspheric data 2nd surface
K = -4.467
A4 = 4.63633e-04, A6 = -2.40019e-06, A8 = 4.27689e-08
5th page
K = -3.000
A4 = -5.57686e-05, A6 = -1.56344e-07, A8 = 1.37614e-09
6th page
K = 0.517
A4 = 3.47119e-05, A6 = -1.50986e-07, A8 = 1.60228e-09
9th page
K = 0.000
A4 = -4.30015e-05
10th page
K = 0.000
A4 = -4.53587e-04, A6 = -1.31203e-05
15th page
K = 0.000
A4 = -3.52390e-04, A6 = -5.03020e-06
20th page
K = 0.000
A4 = -3.84608e-04
21st page
K = 0.000
A4 = 4.08696e-04

Zoom data
WE ST TE
Focal length 4.87 20.61 46.98
FNO. 3.97 5.96 6.94
Angle of view 2ω 81.22 18.96 8.70
Statue height 3.59 3.59 3.59
BF 1.63 1.63 1.63
Total length 67.59 67.59 67.59

d8 0.50 7.36 10.10
d13 10.60 3.75 1.00
d16 6.73 2.95 1.00
d21 9.00 8.48 1.90
d23 2.00 6.30 14.83

Group focal length
f1 = 10.57 f2 = -5.31 f3 = 21.70 f4 = 13.77 f5 = -9.60 f6 = 14.25

Aberration diagrams at the time of focusing on an object point at infinity in Examples 1 to 7 are shown in FIGS. In these aberration diagrams, (a) is the wide angle end, (b) is the intermediate focal length state, (c) is the spherical aberration (SA), astigmatism (AS), distortion (DT), and magnification at the telephoto end. Chromatic aberration (CC) is shown. In each figure, “ω” indicates a half angle of view.

Next, the values of the conditional expressions in each example are listed.

Example 1 Example 2 Example 3 Example 4
(1) f _T / f _W 9.51 9.56 9.55 10.51
(2) f _W / I _H 1.34 1.34 1.33 1.26
(3) | ν _dp1 −ν _dp2 | 32.20 32.20 32.20 26.86
(4) | Δ _2G / f _W | 2.83 2.84 2.84 2.43
(5A) νd _pone 81.54 81.54 81.54 81.54
(5B) νd _poth 49.34 49.34 49.34 54.68
_{(6) f 4G / f T} 0.32 0.32 0.31 0.31
(7) f _RG / f _T 0.52 0.43 0.27 0.26
(A) n _dp1 −n _dp2 0.25 0.25 0.25 0.23
(AA) f _2G / f _T -0.10 -0.10 -0.10 -0.12
(B) N _dn1 1.90 1.90 1.90 1.80
(C) SF _2G | 3.44 4.50 5.06 7.69
_{(D) L T / f T} 1.36 1.35 1.35 1.43
(E) Δ _2G / f _T 0.30 0.30 0.30 0.23
(F) Σ _2G / f _W 0.62 0.64 0.64 0.91

Example 5 Example 6 Example 7
(1) _T / f _W 10.51 9.61 9.64
(2) f _W / I _H 1.26 1.36 1.36
(3) | ν _dp1 −ν _dp2 | 26.86 26.86 26.86
(4) | Δ _2G / f _W | 2.44 1.98 1.97
(5A) ν _dpone 81.54 81.54 81.54
(5B) ν _dpoth 54.68 54.68 54.68
_{(6) f 4G / f T} 0.29 0.31 0.29
(7) f _RG / f _T 0.28 0.30 0.30
(A) n _dp1 −n _dp2 0.23 0.23 0.23
(AA) f2G / fT -0.12 -0.11 -0.11
(B) N _dn1 1.77 1.80 1.77
(C) SF _2G 5.65 5.08 5.39
_{(D) L T / f T} 1.42 1.41 1.41
(E) Δ _2G / f _T 0.23 0.21 0.20
(F) Σ _2G / f _W 0.87 0.84 0.80

(Correction of distortion)
By the way, when the zoom lens of the present invention is used, image distortion may be digitally corrected electrically. The basic concept for digitally correcting image distortion will be described below.
For example, the image height when performing distortion correction can be set to the following value at the wide-angle end. Further, the intermediate state and the telephoto end can be the same as the image heights shown in the numerical examples described above.
In addition, the image height at the wide-angle end assuming distortion correction is shown below. This is an example in which the residual distortion when the electrical correction of the distortion is performed is corrected to be −3% on the short side basis.
The effective imaging area at the wide-angle end is barrel-shaped and is corrected to a rectangle by image processing.
In the intermediate state and the telephoto end, the pincushion type distortion is electrically corrected, and the remaining distortion is corrected to 0%.

Wide-angle end Intermediate state Telephoto end
Example 1 3.62 3.84 3.84
Example 2 3.62 3.84 3.84
Example 3 3.62 3.84 3.84
Example 4 3.35 3.59 3.59
Example 5 3.37 3.59 3.59
Example 6 3.36 3.59 3.59
Example 7 3.36 3.59 3.59

  For example, as shown in FIG. 15, the magnification on the circumference (image height) of the radius R inscribed in the long side of the effective imaging surface around the intersection of the optical axis and the imaging surface is fixed, and this circumference is The standard for correction. Then, correction is performed by moving each point on the circumference (image height) of any other radius r (ω) in a substantially radial direction and concentrically so as to have the radius r ′ (ω). To do.

For example, in FIG. 15, a point P ₁ on the circumference of an arbitrary radius r ₁ (ω) located inside the circle of radius R is a radius r ₁ ′ (ω) circle to be corrected toward the center of the circle. point on the circumference moves to P _2. A point Q ₁ on the circumference of an arbitrary radius r ₂ (ω) located outside the circle of radius R is a radius r ₂ ′ (ω) circumference to be corrected in a direction away from the center of the circle. It is moved to the point Q ₂ of the above.

Here, r ′ (ω) can be expressed as follows.
r ′ (ω) = α · f · tan ω
here,
ω is the half angle of view of the subject,
f is the focal length of the zoom lens.
α is 0 or more and 1 or less.

Here, if the ideal image height corresponding to the circle (image height) of the radius R is Y,
α = R / Y = R / (f · tan ω)
It becomes.

  The optical system is ideally rotationally symmetric with respect to the optical axis, that is, distortion is also generated rotationally symmetric with respect to the optical axis. Therefore, as described above, when the optically generated distortion aberration is electrically corrected, the radius inscribed in the long side of the effective imaging surface around the intersection of the optical axis and the imaging surface on the reproduced image. The magnification on the circumference of the circle of R (image height) is fixed, and the other points on the circumference of the circle (image height) of radius r (ω) are moved in a substantially radial direction to obtain a radius r ′ ( It can be considered advantageous in terms of data amount and calculation amount if it can be corrected by moving it concentrically so that ω).

  However, the optical image is no longer a continuous amount (due to sampling) when captured by the electronic image sensor. Therefore, strictly speaking, the circle with the radius R drawn on the optical image is not an accurate circle unless the pixels on the electronic image sensor are arranged radially.

  That is, in the shape correction of the image data represented for each discrete coordinate point, there is no circle that can fix the magnification. Therefore, it is preferable to use a method of determining the coordinates (Xi ′, Yj ′) of the movement destination for each pixel (Xi, Yj). When two or more points (Xi, Yj) have moved to the coordinates (Xi ′, Yj ′), the average value of the values of each pixel is taken. If there is no moving point, interpolation may be performed using the values of the coordinates (Xi ′, Yj ′) of some surrounding pixels.

  Such a method is particularly distorted with respect to the optical axis due to manufacturing errors of an optical system and an electronic imaging device in an electronic imaging apparatus having a zoom lens, and the circle with the radius R drawn on the optical image is It is effective for correction when it becomes asymmetric. Further, it is effective for correction when a geometric distortion or the like occurs when a signal is reproduced as an image in an image sensor or various output devices.

  In the electronic imaging apparatus of the present invention, in order to calculate the correction amount r ′ (ω) −r (ω), r (ω), that is, the relationship between the half field angle and the image height, or the real image height r and the ideal image height. The relationship between r ′ / α may be recorded on a recording medium built in the electronic imaging apparatus.

  Note that the radius R preferably satisfies the following conditional expression so that the image after distortion correction does not have an extremely short amount of light at both ends in the short side direction.

0 ≦ R ≦ 0.6Ls
Here, Ls is the length of the short side of the effective imaging surface.

Preferably, the radius R satisfies the following conditional expression.
0.3Ls ≦ R ≦ 0.6Ls
Furthermore, it is most advantageous to make the radius R coincide with the radius of the inscribed circle in the short side direction of the substantially effective imaging surface. In the case of correction in which the magnification is fixed in the vicinity of the radius R = 0, that is, in the vicinity of the axis, there is a slight disadvantage in terms of image quality, but the effect of reducing the size is ensured even if the angle of view is widened. it can.

The focal length section that needs to be corrected is divided into several focal zones. And approximately near the telephoto end in the divided focal zone,
r ′ (ω) = α · f · tan ω
You may correct | amend with the same correction amount as the case where the correction result which satisfies is obtained.

  Here, in this case, some barrel distortion remains at the wide-angle end in the divided focal zone. Further, if the number of divided zones is increased, it becomes unnecessary to store extraneous data necessary for correction on the recording medium, which is not preferable. Therefore, one or several coefficients related to each focal length in the divided focal zone are calculated in advance. This coefficient may be determined on the basis of simulation or actual measurement.

And approximately near the telephoto end in the divided zone,
r ′ (ω) = α · f · tan ω
It is also possible to calculate a correction amount when a correction result satisfying the above is obtained, and uniformly multiply the correction amount for each focal distance to obtain a final correction amount.

By the way, if there is no distortion in the image obtained by imaging an object at infinity,
f = y / tan ω
Is established.
Here, y is the height (image height) of the image point from the optical axis, f is the focal length of the imaging system (in the present invention, the zoom lens), and ω is the image point connecting from the center on the imaging surface to the y position. Is an angle (subject half-field angle) with respect to the optical axis in the object direction corresponding to.

If the imaging system has barrel distortion,
f> y / tan ω
It becomes. That is, if the focal length f of the imaging system and the image height y are constant, the value of ω increases.

(Digital camera)
The zoom lens of the present invention as described above forms an object image, and the image can be received by an electronic image sensor such as a CCD. The embodiment is illustrated below.

  FIGS. 16 to 18 are conceptual diagrams of structures in which the zoom lens according to the present invention is incorporated in the photographing optical system 141 of the digital camera. 16 is a front perspective view showing the appearance of the digital camera 140, FIG. 17 is a rear perspective view thereof, and FIG. 18 is a cross-sectional view showing the configuration of the digital camera 140. In this example, the digital camera 140 includes a photographing optical system 141 having a photographing optical path 142, a finder optical system 143 having a finder optical path 144, a shutter 145, a flash 146, a liquid crystal display monitor 147, and the like. When the shutter 145 disposed in the position is pressed, photographing is performed through the photographing optical system 141, for example, the optical path bending zoom lens according to the first embodiment in conjunction therewith. An object image formed by the photographing optical system 141 is formed on the imaging surface of the CCD 149 through a near-infrared cut filter and an optical low-pass filter F. The object image received by the CCD 149 is displayed as an electronic image on a liquid crystal display monitor 147 provided on the back of the camera via the processing means 151. Further, the processing means 151 is connected to a recording means 152 so that a photographed electronic image can be recorded. The recording unit 152 may be provided separately from the processing unit 151, or may be configured to perform recording / writing electronically using a flexible disk, a memory card, an MO, or the like. Further, instead of the CCD 149, a silver salt camera in which a silver salt film is arranged may be configured.

  Further, a finder objective optical system 153 is disposed on the finder optical path 144. The object image formed by the finder objective optical system 153 is formed on the field frame 157 of the Porro prism 155 that is an image erecting member. Behind this polyprism 155, an eyepiece optical system 159 for guiding an erect image to the observer eyeball E is disposed. Cover members 150 are disposed on the incident side of the photographing optical system 141 and the finder objective optical system 153 and on the exit side of the eyepiece optical system 159, respectively.

  The digital camera 140 configured in this manner is a zoom lens having a high zoom ratio and a high optical performance of the photographing optical system 141 of about 10 times. Therefore, the digital camera 140 is a low-cost digital camera with high performance and extremely thin depth direction. Can be realized.

  In addition, in the example of FIG. 18, although a parallel plane board is arrange | positioned as the cover member 150, you may omit.

(Internal circuit configuration)
FIG. 19 is a block diagram showing the internal circuitry of the main part of the digital camera 140. In the following description, the processing means includes, for example, the CDS / ADC unit 124, the temporary storage memory 117, the image processing unit 118, and the like, and the storage means includes, for example, the storage medium unit 119.

  As shown in FIG. 19, the digital camera 140 is connected to the operation unit 112, the control unit 113 connected to the operation unit 112, and the control signal output port of the control unit 113 via buses 114 and 115. An imaging drive circuit 116, a temporary storage memory 117, an image processing unit 118, a storage medium unit 119, a display unit 120, and a setting information storage memory unit 121 are provided.

  The temporary storage memory 117, the image processing unit 118, the storage medium unit 119, the display unit 120, and the setting information storage memory unit 121 are configured so that data can be input or output with each other via the bus 122. In addition, a CCD 149 and a CDS / ADC unit 124 are connected to the imaging drive circuit 116.

  The operation unit 112 includes various input buttons and switches, and is a circuit that notifies the control unit of event information input from the outside (camera user) via these input buttons and switches.

  The control unit 113 is a central processing unit composed of, for example, a CPU and the like. The control unit 113 includes a program memory (not shown) and is input from the camera user via the operation unit 112 according to a program stored in the program memory. This is a circuit that controls the entire digital camera 140 in response to an instruction command.

  The CCD 149 receives an object image formed through the photographing optical system 141 according to the present invention. The CCD 149 is an image pickup element that is driven and controlled by the image pickup drive circuit 116 and converts the light amount of each pixel of the object image into an electric signal and outputs the electric signal to the CDS / ADC unit 124.

  The CDS / ADC unit 124 amplifies the electric signal input from the CCD 149 and performs analog / digital conversion, and temporarily stores the raw video data (Bayer data, hereinafter referred to as RAW data) that has just been subjected to the amplification and digital conversion. This is a circuit for outputting to the storage memory 117.

  The temporary storage memory 117 is a buffer made of, for example, SDRAM or the like, and is a memory device that temporarily stores the RAW data output from the CDS / ADC unit 124. The image processing unit 118 reads out the RAW data stored in the temporary storage memory 117 or the RAW data stored in the storage medium unit 119, and performs various corrections including distortion correction based on the image quality parameter designated from the control unit 113. It is a circuit that performs image processing electrically.

  The recording medium unit 119 detachably mounts a card-type or stick-type recording medium made of, for example, a flash memory, and RAW data transferred from the temporary storage memory 117 to the card-type or stick-type flash memory. This is a control circuit of an apparatus for recording and holding image data processed by the image processing unit 118.

  The display unit 120 includes a liquid crystal display monitor, and is a circuit that displays an image, an operation menu, and the like on the liquid crystal display monitor. The setting information storage memory unit 121 stores a ROM unit in which various image quality parameters are stored in advance, and an image quality parameter selected by an input operation of the operation unit 112 among the image quality parameters read from the ROM unit. RAM section is provided. The setting information storage memory unit 121 is a circuit that controls input and output to these memories.

  In the digital camera 140 configured in this way, the imaging optical system 141 has a sufficiently wide angle range and a compact configuration according to the present invention, and the imaging performance is extremely stable at a high zoom ratio and in a full zoom ratio range. Therefore, high performance, downsizing, and wide angle of view can be realized. In addition, fast focusing operation on the wide-angle side and the telephoto side is possible.

  As described above, the imaging apparatus according to the present invention is useful for an imaging apparatus in which the thickness direction of the imaging apparatus is reduced by disposing a reflection member that reflects an optical path in a zoom lens.

G1 ... 1st lens group G2 ... 2nd lens group G3 ... 3rd lens group G4 ... 4th lens group G5 ... 5th lens group G6 ... 6th lens group S ... Aperture stop F ... Low pass filter C ... Cover glass P ... Prism I ... Image plane 112 ... Operation unit 113 ... Control unit 114 ... Bus 115 ... Bus 116 ... Imaging drive circuit 117 ... Temporary storage memory 118 ... Image processing unit 119 ... Storage medium unit 120 ... Display unit 121 ... Setting information storage memory unit 122 ... Bus 124 ... CDS / ADC section 140 ... Digital camera 141 ... Shooting optical system 142 ... Shooting optical path 143 ... Viewfinder optical system 144 ... Viewfinder optical path 145 ... Shutter button 146 ... Flash 147 ... Liquid crystal display monitor 149 ... CCD
150: cover member 151 ... processing means 152 ... recording means 153 ... finder objective optical system 155 ... erecting prism 157 ... field frame 159 ... eyepiece optical system

Claims (24)

An image pickup apparatus comprising a zoom lens and an image pickup device having an image pickup surface for converting an image obtained by the zoom lens into an electric signal,
The zoom lens, in order from the object side to the image side,
A first lens group having a reflecting member having a reflecting surface for reflecting the optical path and having a positive refractive power;
A second lens group having negative refractive power;
A rear lens group including at least three lens groups including a third lens group, a fourth lens group, and a fifth lens group in order from the object side, and having a positive refractive power as a whole;
Having an aperture stop disposed between the second lens group and the fourth lens group;
When zooming from the wide-angle end to the telephoto end,
The first lens group is fixed;
The second lens group moves so as to be positioned closer to the image side at the telephoto end than at the wide-angle end,
The interval between the lens groups changes,
The first lens group includes, in order from the object side to the image side, a negative lens component, the reflecting member, and a rear sub lens group including a first positive lens and a second positive lens.
The second lens group has a plurality of lenses including a negative lens,
An image pickup apparatus satisfying the following conditional expressions (1), (2), and (AA).
7 <f _T / f _W <30 (1)
0.5 <f _W /IH<1.38 (2)
−0.2 <f _2G / f _T <−0.05 (AA)
here,
f _T is the focal length of the entire zoom lens system at the telephoto end,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
IH is the maximum image height of the effective imaging area of the imaging surface,
f _2G is the focal length of the second lens group,
And
The lens component is a lens body divided by a surface in contact with air on the lens effective surface, and is a single lens or a cemented lens. An image pickup apparatus comprising a zoom lens and an image pickup device having an image pickup surface for converting an image obtained by the zoom lens into an electric signal,
The zoom lens, in order from the object side to the image side,
A first lens group having a reflecting member having a reflecting surface for reflecting the optical path and having a positive refractive power;
A second lens group having negative refractive power;
A rear lens group having a positive refractive power as a whole including a plurality of lens groups including a third lens group, a fourth lens group, and a fifth lens group in order from the object side;
Having an aperture stop disposed between the second lens group and the fourth lens group;
When zooming from the wide-angle end to the telephoto end,
The first lens group is fixed;
The second lens group moves so as to be positioned closer to the image side at the telephoto end than at the wide-angle end,
The interval between the lens groups changes,
The first lens group includes, in order from the object side to the image side, a negative lens component, the reflecting member, and a rear sub lens group including a first positive lens and a second positive lens.
The second lens group has a plurality of lenses including a negative lens,
The rear lens group has at least three lens units having a positive refractive power,
An image pickup apparatus satisfying the following conditional expressions (3), (4), and (AA).
−0.2 <f _2G / f _T <−0.05 (AA)
1.8 <Δ _2G / f _W <15 (4)
16.5 <| ν _dp1 −ν _dp2 | <80 (3)
here,
f _T is the focal length of the entire zoom lens system at the telephoto end,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
f _2G is the focal length of the second lens group,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, where the movement toward the image side is a positive sign;
ν _dp1 is the Abbe number based on the d-line of the first positive lens in the first lens group,
ν _dp2 is the Abbe number based on the d-line of the second positive lens in the first lens group,
And
The lens component is a lens body separated by a surface in contact with air at the lens effective surface, and is composed of a single lens or a cemented lens,
The Abbe number is (n _d1 −1) / (n _F1 −n _C1 ),
n _d1 , n _C1 , and n _F1 are refractive indexes of the d-line, C-line, and F-line of the first positive lens or the second positive lens,
It is. The third lens group has a positive refractive power,
The fourth lens group has a positive refractive power,
The imaging apparatus according to claim 2, wherein the fifth lens group has a positive refractive power.   The imaging apparatus according to claim 1, wherein the rear lens group group includes at least three lens groups having a positive refractive power. The third lens group has a positive refractive power,
The fourth lens group has a positive refractive power,
The imaging apparatus according to claim 4, wherein the fifth lens group has a positive refractive power. The imaging apparatus according to claim 1, wherein the following conditional expression (4) is satisfied.
1.8 <Δ _2G / f _W <15 (4)
here,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, with the movement toward the image side being a positive sign,
And
The lens component is a lens body that is delimited by a surface in contact with air on the lens effective surface, and is configured by a single lens or a cemented lens. The imaging apparatus according to claim 1, wherein the following conditional expression (3) is satisfied.
16.5 <| ν _dp1 −ν _dp2 | <80 (3)
here,
ν _dp1 is the Abbe number based on the d-line of the first positive lens in the first lens group,
ν _dp2 is the Abbe number based on the d-line of the second positive lens in the first lens group,
And
The lens component is a lens body separated by a surface in contact with air at the lens effective surface, and is composed of a single lens or a cemented lens,
The Abbe number is (n _d1 −1) / (n _F1 −n _C1 ),
n _d1 , n _C1 , and n _F1 are refractive indexes of the d-line, C-line, and F-line of the first positive lens or the second positive lens,
It is. The imaging device according to claim 1, wherein the lens closest to the object side of the second lens group satisfies the following conditional expression (B).
N _dn1 ≧ 1.60 (B)
here,
N _dn1 is the d-line refractive index of the negative lens closest to the object among the plurality of lenses in the second lens group. The second lens group includes a single lens composed of a first negative lens and a cemented lens composed of a second negative lens and a positive lens.
Both the image side surfaces of the first negative lens and the second negative lens have a shape with a concave surface facing the image side,
The imaging apparatus according to claim 1, wherein the following conditional expression (C) is satisfied.
2.0 <SF _2G <30.0 (C)
here,
SF _2G = | (R ₁ + R ₂ ) / (R ₁ −R 2) |
R ₁ is a paraxial radius of curvature on the image plane side of the first negative lens,
R ₂ is the paraxial radius of curvature of the image side surface of the second negative lens in the cemented lens,
It is.   The imaging apparatus according to claim 1, wherein the most object-side negative lens in the second lens group has an aspheric lens surface. The imaging apparatus according to claim 1, wherein the following conditional expression (D) is satisfied.
1.0 <L _T / f _T <2.0 (D)
here,
L _T is the distance from the entrance surface of the zoom lens at the telephoto end to the image plane is obtained by calculating the back focus as an air-equivalent length. The imaging apparatus according to claim 1, wherein the second lens group satisfies the following conditional expression (E).
0.05 <Δ _2G / f _T <0.4 (E)
here,
Δ _2G is the amount of movement of the second lens group at the telephoto end with respect to the wide-angle end, where the movement toward the image side is a positive sign. The imaging apparatus according to claim 1, wherein the second lens group satisfies the following conditional expression (F).
0.5 <Σ _2G / f _W <1.0 (F)
here,
Σ _2G is the thickness of the second lens group on the optical axis,
f _W is the focal length of the entire zoom lens system at the wide-angle end,
It is.   The imaging apparatus according to claim 1, wherein the aperture stop is fixed at the time of zooming from the wide-angle end to the telephoto end.   2. The third lens group has a positive refractive power, and the third lens group and the aperture stop are fixed when zooming from a wide angle end to a telephoto end. Or the imaging device of Claim 2. The third lens group has a positive refractive power,
The fourth lens group has a positive refractive power,
The fifth lens group has negative refractive power,
The imaging device according to claim 1, wherein a sixth lens group having a positive refractive power is disposed on the image side of the fifth lens group. Either one of the first positive lens and the second positive lens satisfies the following conditional expression (5A), and the other positive lens satisfies the following conditional expression (5B) The imaging device according to claim 1 or 2, wherein
ν _dpone > 60 (5A)
ν _dpoth <60 (5B)
here,
ν _dpone is the Abbe number based on the d-line of one of the first positive lens and the second positive lens,
ν _dpoth is the Abbe number of the other d-line reference of the first positive lens and the second positive lens,
It is. The imaging apparatus according to claim 17, wherein a difference in refractive index between the first positive lens and the second positive lens satisfies the conditional expression (A).
0.1 <n _dp1 −n _dp2 <0.65 (A)
here,
n _dp1 is the d-line-based refractive index of one of the first positive lens and the second positive lens;
n _dp2 is the other d-line-based refractive index of the first positive lens and the second positive lens,
The refractive index based on the d-line of the positive lens with the smaller Abbe number is n _dp1 ,
It is. The third lens group and the fourth lens group have positive refractive power;
When zooming from the wide-angle end to the telephoto end,
The imaging apparatus according to claim 17, wherein the brightness stop and the third lens group are fixed, and the fourth lens group is moved in an optical axis direction. The fifth lens group has a positive refractive power;
When zooming from the wide-angle end to the telephoto end,
The imaging device according to claim 19, wherein the fifth lens group is fixed. The fifth lens group has negative refractive power;
A sixth lens group having a positive refractive power is disposed on the image side of the fifth lens group;
When zooming from the wide-angle end to the telephoto end,
The distance between the fifth lens group and the sixth lens group changes;
The image pickup apparatus according to claim 19, wherein the fifth lens group is further moved during focusing. The imaging apparatus according to claim 19, wherein the fourth lens group satisfies the following conditional expression (6).
0.1 <f _4G / f _T <0.6 (6)
here,
f _4G is the focal length of the fourth lens group,
f _T is the focal length of the entire zoom lens system at the telephoto end,
It is. The image pickup apparatus according to claim 19, wherein the most image side lens group in the zoom lens satisfies the following conditional expression (7).
0.1 <f _RG / f _T <0.8 (7)
f _RG is the focal length of the lens unit closest to the image side in the zoom lens;
f _T is the focal length of the entire zoom lens system at the telephoto end,
It is.   3. The image conversion unit according to claim 1, further comprising: an image conversion unit configured to convert an electric signal output from the image sensor and including distortion by the zoom lens into an image signal in which distortion is corrected by image processing. Imaging device.