JP2011090080A - Photographic lens, imaging apparatus, and method for adjusting the photographic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost photographic lens that achieves satisfactory optical performance, and to provide an imaging apparatus, and a method for adjusting the photographic lens. <P>SOLUTION: The photographic lens ZL mounted in an electronic still camera 1 or the like includes, in order from the object side, a first lens group G1 having positive and negative refractive powers, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. In addition, the photographic lens ZL has a structure which can tilt the first lens group G1 relative to an optical axis, and which can shift the third lens group G3 in a direction orthogonal to the optical axis. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photographing lens, an imaging device, and a method for adjusting a photographing lens.

  Conventionally, various photographing lenses suitable for an imaging apparatus such as a photographic camera, an electronic still camera, and a video camera have been proposed (for example, see Patent Document 1).

JP 2003-90958 A

  However, in the conventional photographic lens, if an eccentric error occurs during manufacturing, the imaging performance deteriorates. In order to prevent such deterioration of imaging performance, it is necessary to reduce the occurrence of eccentricity errors by increasing the processing accuracy of each lens, lens chamber, and lens components such as mechanical components. There is a problem that it is difficult to reduce the cost if the accuracy is increased.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and is capable of achieving good optical performance, a low-cost photographing lens, a method for adjusting the photographing lens, and an imaging apparatus including such a photographing lens. The purpose is to provide.

  In order to solve the above problems, a photographic lens according to a first aspect of the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a negative lens group. And a third lens group having refractive power. The first lens group can be tilted with respect to the optical axis, and the third lens group can be shifted in a direction perpendicular to the optical axis.

  The photographic lens according to the second aspect of the present invention includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens having a negative refractive power. And a structure capable of shifting the first lens group and the third lens group in a direction perpendicular to the optical axis.

  In such a photographing lens, it is preferable that the third lens group has a negative meniscus lens having a concave surface facing the object side.

  In such a photographing lens, it is preferable that the first lens group has one or more positive lenses and one or more negative lenses.

  At this time, the first lens group preferably includes two or more positive lenses and one or more negative lenses.

  Further, in such a photographing lens, the second lens group includes at least one variable air interval, and when zooming from the shortest focal length state to the longest focal length state, the air interval is changed to change the focal length. It is preferable to change.

  Further, in such a photographing lens, it is preferable to change the focal length by changing the air gap between the first lens group and the second lens group when zooming from the shortest focal length state to the longest focal length state. .

Further, in such a photographing lens, when the focal length of the first lens group is f1, and the focal length of the entire system in the longest focal length state is fT, the following expression 0.30 <f1 / fT <0.65
It is preferable to satisfy the following conditions.

Also, in such a photographing lens, when the focal length of the third lens group is f3 and the focal length of the entire system in the longest focal length state is fT, the following expression 0.30 <(− f3) / fT < 0.85
It is preferable to satisfy the following conditions.

  The photographic lens according to the third aspect of the present invention 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, and a third lens having a positive refractive power. The lens unit includes a lens group and a fourth lens group having a positive refractive power, and has a structure capable of tilting the second lens group and the fourth lens group with respect to the optical axis.

  In such a photographing lens, it is preferable that the second lens group includes one or more positive lenses and two or more negative lenses.

  Further, such a photographing lens has an air gap between the first lens group and the second lens group, and the second lens group and the third lens group when zooming from the shortest focal length state to the longest focal length state. It is preferable to change the focal distance by changing the air gap between the two.

  Thus, when zooming from the shortest focal length state to the longest focal length state, it is preferable to change the focal length by changing the air gap between the third lens group and the fourth lens group.

  In such a photographic lens, the third lens group includes at least one variable air interval. When the magnification is changed from the shortest focal length state to the longest focal length state, the third lens group changes the air interval to change the focal length. It is preferable to change.

Further, in such a photographing lens, when the focal length of the second lens group is f2, and the focal length of the entire system in the longest focal length state is fT, the following expression 0.09 <(− f2) / fT < 0.20
It is preferable to satisfy the following conditions.

Further, in such a photographing lens, when the focal length of the fourth lens unit is f4 and the focal length of the entire system in the longest focal length state is fT, the following formula 0.40 <f4 / fT <0.78
It is preferable to satisfy the following conditions.

  An imaging apparatus according to the present invention includes any one of the above-described photographing lenses.

  In addition, the method for adjusting a photographic lens according to the first aspect of the present invention includes a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. The first lens group is tilted with respect to the optical axis, and the third lens group is shifted in a direction orthogonal to the optical axis.

  In addition, in the adjustment method of the taking lens according to the second aspect of the present invention, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a negative refractive power. And a third lens group having a third lens group, wherein the first lens group and the third lens group are shifted in a direction perpendicular to the optical axis.

  In the third aspect of the present invention, there is provided a method for adjusting a photographic lens, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power. A method for adjusting a photographic lens, which includes a third lens group having a fourth lens group having positive refractive power, and tilting the second lens group and the fourth lens group with respect to the optical axis.

  By configuring the present invention as described above, it is possible to obtain a low-cost photographic lens, imaging device, and photographic lens adjustment method that can achieve good optical performance.

It is sectional drawing which shows the lens structure of the imaging lens by 1st Example. It is sectional drawing which showed typically the mechanism of the imaging lens of 1st Example. FIG. 3 is a plan view of the photographic lens of the first example when viewed from the object side, and schematically shows a mechanism in which a first holding member that holds a first lens group is fixed to a lens barrel member by a screw. It is the top view which looked at the imaging lens of 1st Example from the image side, and is the figure which showed typically the mechanism by which the 2nd holding member holding a 3rd lens group is fixed to a lens barrel member with a screw. FIG. 6 is a diagram showing lateral aberration when no decentration error occurs during the production of the taking lens according to Example 1, where (a) shows lateral aberration with respect to an image height of 15 mm, and (b) shows lateral aberration with respect to an image height of 0 mm. (C) is the figure which showed the lateral aberration with respect to -15 mm of image height, respectively. It is a figure which shows a lateral aberration when an eccentric error generate | occur | produces at the time of manufacture of the imaging lens which concerns on 1st Example, (a) shows the lateral aberration with respect to image height 15mm, (b) shows the lateral aberration with respect to image height 0mm, (C) is the figure which showed the lateral aberration with respect to image height -15mm, respectively. It is a figure which shows the lateral aberration at the time of adjusting the decentration error which generate | occur | produced at the time of manufacture of the imaging lens which concerns on 1st Example using an adjustment mechanism, (a) is a lateral aberration with respect to image height 15mm, (b) is. (C) is a diagram showing lateral aberration with respect to an image height of -15 mm. It is sectional drawing which shows the lens structure of the photographic lens by 2nd Example. It is sectional drawing which showed typically the mechanism of the imaging lens of 2nd Example. It is the top view which looked at the imaging lens of 2nd Example from the object side, and is the figure which showed typically the mechanism in which the 1st holding member holding a 1st lens group is fixed to a lens barrel member with a screw. It is the top view which looked at the imaging lens of 2nd Example from the image side, and is the figure which showed typically the mechanism in which the 2nd holding member holding a 3rd lens group is fixed to a lens barrel member with a screw. It is a figure which shows the lateral aberration when an eccentric error does not generate | occur | produce at the time of manufacture of the photographic lens which concerns on 2nd Example, (a) is lateral aberration with respect to image height 15mm, (b) is lateral aberration with respect to image height 0mm. (C) is the figure which showed the lateral aberration with respect to -15 mm of image height, respectively. It is a figure which shows the lateral aberration when an eccentric error generate | occur | produces at the time of manufacture of the photographic lens which concerns on 2nd Example, (a) is lateral aberration with respect to image height 15mm, (b) is lateral aberration with respect to image height 0mm, (C) is the figure which showed the lateral aberration with respect to image height -15mm, respectively. It is a figure which shows the lateral aberration at the time of adjusting the eccentric error which generate | occur | produced at the time of manufacture of the imaging lens which concerns on 2nd Example using an adjustment mechanism, (a) is a lateral aberration with respect to image height of 15 mm, (b) is. (C) is a diagram showing lateral aberration with respect to an image height of -15 mm. It is sectional drawing which shows the lens structure of the photographic lens by 3rd Example. It is sectional drawing which showed typically the mechanism of the imaging lens of 3rd Example. It is the top view which looked at the imaging lens of 3rd Example from the image side, and is the figure which showed typically the mechanism in which the 2nd holding member holding a 3rd lens group is fixed to a lens barrel member with a screw. It is the perspective view which showed typically the mechanism of the 1st holding member holding the imaging lens of 3rd Example from the object side diagonal direction. It is a figure which shows the lateral aberration when an eccentric error does not generate | occur | produce at the time of manufacture of the photographic lens which concerns on 3rd Example, (a) is lateral aberration with respect to image height 15mm, (b) is lateral aberration with respect to image height 0mm. (C) is the figure which showed the lateral aberration with respect to -15 mm of image height, respectively. It is a figure which shows a lateral aberration when an eccentric error generate | occur | produces at the time of manufacture of the photographic lens which concerns on 3rd Example, (a) is a lateral aberration with respect to image height 15mm, (b) is a lateral aberration with respect to image height 0mm, (C) is the figure which showed the lateral aberration with respect to image height -15mm, respectively. It is a figure which shows the lateral aberration at the time of adjusting the eccentric error which generate | occur | produced at the time of manufacture of the imaging lens which concerns on 3rd Example using an adjustment mechanism, (a) is a lateral aberration with respect to image height 15mm, (b) is. (C) is a diagram showing lateral aberration with respect to an image height of -15 mm. 1 is a cross-sectional view of a digital single-lens reflex camera equipped with a photographing lens according to the present embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification, the wide-angle end state and the telephoto end state refer to an infinitely focused state unless otherwise specified. First, the photographic lens ZL according to the first embodiment will be described. As shown in FIG. 1, the photographing lens ZL (ZL1) according to the first embodiment includes a first lens group G1 having a positive refractive power and a second lens having a positive refractive power in order from the object side. It is composed of a group G2 and a third lens group G3 having negative refractive power. The taking lens ZL1 has a structure in which the first lens group G1 can be tilted with respect to the optical axis, and the third lens group G3 can be shifted in a direction perpendicular to the optical axis.

  With this configuration, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and periphery of the shooting screen due to the eccentricity error during manufacturing, and to achieve good optical performance without increasing the cost associated with improving the component accuracy. The achieved photographic lens ZL1 can be provided.

  In the photographic lens ZL1 according to the first embodiment, it is desirable that the third lens group G3 includes a negative meniscus lens having a concave surface directed toward the object side. With this configuration, by shifting the third lens group G3, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and the periphery of the photographing screen due to the eccentric error during manufacture.

  In the photographic lens ZL1 according to the first embodiment, it is desirable that the first lens group G1 includes one or more positive lenses and one or more negative lenses. With this configuration, by tilting the first lens group G1, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and the periphery of the photographing screen due to the eccentric error during manufacturing. More preferably, the first lens group G1 preferably includes two or more positive lenses and one or more negative lenses. With this configuration, the first lens group G1 is tilted, thereby decentering during manufacture. Deterioration of the imaging performance at the center and the periphery of the photographing screen due to an error can be corrected more favorably.

  The photographic lens ZL1 according to the first embodiment includes at least one variable air interval in the second lens group G2, and the air interval is changed when zooming from the shortest focal length state to the longest focal length state. The focal length can be changed by changing. Alternatively, the focal distance can be changed by changing the air gap between the first lens group G1 and the second lens group G2. That is, since the variable focal length lens has more movable parts than a lens having a fixed focal length, the influence of the manufacturing error on the imaging performance tends to be large. The photographic lens ZL1 and the adjustment method can be made more effective.

  In the photographic lens ZL1 according to the first embodiment, when the focal length of the first lens group G1 is f1, and the focal length of the entire photographic lens ZL1 in the longest focal length state is fT, the following conditions are satisfied. It is desirable to satisfy Formula (1).

0.30 <f1 / fT <0.65 (1)

  Conditional expression (1) is a conditional expression that defines the focal length of the first lens group G1 suitable for adjusting the manufacturing error by tilting the first lens group G1 with respect to the optical axis. When the upper limit of conditional expression (1) is exceeded, the refractive power of the first lens group G1 decreases, the change in imaging performance with respect to the tilt of the first lens group G1 decreases, and the first for adjusting manufacturing errors. This is not preferable because the tilt amount of the lens group G1 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 0.60. On the other hand, if the lower limit of conditional expression (1) is not reached, the refractive power of the first lens group G1 becomes large, the change in imaging performance with respect to the tilt of the first lens group G1 becomes too sensitive, and the adjustment of the manufacturing error. Therefore, it is necessary to adjust the tilt angle with high accuracy when tilting the first lens group G1. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 0.35.

  The photographic lens ZL1 according to the first embodiment has the following conditions, where the focal length of the third lens group G3 is f3 and the focal length of the entire photographic lens ZL1 system in the longest focal length state is fT. It is desirable to satisfy Formula (2).

0.30 <(− f3) / fT <0.85 (2)

  Conditional expression (2) is a conditional expression that defines the focal length of the third lens group G3 suitable for adjusting the manufacturing error by shifting the third lens group G3 in the direction orthogonal to the optical axis. When the upper limit of conditional expression (2) is exceeded, the refractive power of the third lens group G3 becomes small, the change in imaging performance with respect to the shift of the third lens group G3 becomes small, and a third for adjusting manufacturing errors. This is not preferable because the shift amount of the lens group G3 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.80. On the other hand, if the lower limit value of conditional expression (2) is not reached, the refractive power of the third lens group G3 becomes large, and the change in the imaging performance with respect to the shift of the third lens group G3 becomes too sensitive, and adjustment of the manufacturing error. Therefore, when the third lens group G3 is shifted, highly accurate position adjustment is required. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.35.

  Next, the photographic lens ZL according to the second embodiment will be described. As shown in FIG. 8, the taking lens ZL (ZL2) according to the second embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power and a second lens having a positive refractive power. The lens unit includes a group G2 and a third lens group G3 having a negative refractive power, and has a structure capable of shifting the first lens group G1 and the third lens group G3 in a direction orthogonal to the optical axis.

  With this configuration, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and periphery of the shooting screen due to the eccentricity error during manufacturing, and good optical performance has been achieved without causing an increase in costs associated with improving component accuracy. A photographic lens ZL2 can be provided.

  In the photographic lens ZL2 according to the second embodiment, it is desirable that the third lens group G3 includes a negative meniscus lens having a concave surface directed toward the object side. With this configuration, by shifting the third lens group G3, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and the periphery of the photographing screen due to the eccentric error during manufacture.

  In the photographing lens ZL2 according to the second embodiment, it is desirable that the first lens group G1 includes one or more positive lenses and one or more negative lenses. With this configuration, by shifting the first lens group G1, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and the periphery of the photographing screen due to the eccentric error during manufacture. More preferably, the first lens group G1 preferably includes two or more positive lenses and one or more negative lenses. With this configuration, the first lens group G1 is shifted, thereby decentering during manufacture. Deterioration of the imaging performance at the center and the periphery of the photographing screen due to an error can be corrected more favorably.

  In addition, the photographic lens ZL2 according to the second embodiment includes at least one variable air interval in the second lens group G2, and the air interval is changed when zooming from the shortest focal length state to the longest focal length state. The focal length can be changed by changing. Alternatively, the focal distance can be changed by changing the air gap between the first lens group G1 and the second lens group G2. That is, since the variable focal length lens has more movable parts than a lens having a fixed focal length, the influence of the manufacturing error on the imaging performance tends to be large. The photographic lens ZL2 and the adjustment method can be made more effective.

  In the photographic lens ZL2 according to the second embodiment, when the focal length of the first lens group G1 is f1, and the focal length of the entire photographic lens ZL2 in the longest focal length state is fT, the following conditions are satisfied. It is desirable to satisfy Formula (3).

0.30 <f1 / fT <0.65 (3)

  Conditional expression (3) is a conditional expression that defines the focal length of the first lens group G1 that is suitable for adjusting the manufacturing error by shifting the first lens group G1 in the direction orthogonal to the optical axis. If the upper limit value of conditional expression (3) is exceeded, the refractive power of the first lens group G1 becomes small, the change in imaging performance with respect to the shift of the first lens group G1 becomes small, and the first for adjusting manufacturing errors. This is not preferable because the shift amount of the lens group G1 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.60. On the other hand, if the lower limit value of conditional expression (3) is not reached, the refractive power of the first lens group G1 becomes large, the change in the imaging performance with respect to the shift of the first lens group G1 becomes too sensitive, and the adjustment of the manufacturing error. Therefore, high-precision position adjustment is required when shifting the first lens group G1. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.35.

  In the photographic lens ZL2 according to the second embodiment, when the focal length of the third lens group G3 is f3 and the focal length of the entire photographic lens ZL2 in the longest focal length state is fT, the following conditions are satisfied. It is desirable to satisfy Formula (4).

0.30 <(− f3) / fT <0.85 (4)

  Conditional expression (4) is a conditional expression that defines the focal length of the third lens group G3 that is suitable for adjusting the manufacturing error by shifting the third lens group G3 in the direction orthogonal to the optical axis. When the upper limit of conditional expression (4) is exceeded, the refractive power of the third lens group G3 becomes small, the change in imaging performance with respect to the shift of the third lens group G3 becomes small, and a third for adjusting manufacturing errors. This is not preferable because the shift amount of the lens group G3 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 0.80. On the other hand, if the lower limit value of conditional expression (4) is not reached, the refractive power of the third lens group G3 becomes large, and the change in imaging performance with respect to the shift of the third lens group G3 becomes too sensitive, and the adjustment of the manufacturing error. Therefore, when the third lens group G3 is shifted, highly accurate position adjustment is required. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 0.35.

  Next, a photographic lens ZL according to the third embodiment will be described. As shown in FIG. 15, the taking lens ZL (ZL3) according to the third embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power and a second lens having a negative refractive power. It consists of a group G2, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power. The second lens group G2 and the fourth lens group G4 can be tilted with respect to the optical axis. It has a simple structure.

  With this configuration, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and periphery of the shooting screen due to the eccentricity error during manufacturing, and good optical performance has been achieved without causing an increase in costs associated with improving component accuracy. A photographic lens ZL3 can be provided

  In the photographic lens ZL3 according to the third embodiment, it is desirable that the second lens group G2 includes one or more positive lenses and two or more negative lenses. With this configuration, by tilting the second lens group G2, it is possible to satisfactorily correct the deterioration of the imaging performance at the center and the periphery of the photographing screen due to the eccentric error during manufacture.

  In addition, the photographic lens ZL3 according to the third embodiment has an air gap between the first lens group G1 and the second lens group G2 and a second distance when zooming from the shortest focal length state to the longest focal length state. The focal distance can be changed by changing the air gap between the lens group G2 and the third lens group G3. Further, the focal distance can be changed by changing the air gap between the third lens group G3 and the fourth lens group G4. Alternatively, the third lens group G3 includes at least one variable air interval, and is configured to change the focal length by changing the air interval when zooming from the shortest focal length state to the longest focal length state. Can do. That is, since the variable focal length lens has more movable parts than a lens having a fixed focal length, the influence of the manufacturing error on the imaging performance tends to be large. The photographic lens ZL3 and the adjusting method can be made more effective.

  The photographic lens ZL3 according to the third embodiment has the following conditions when the focal length of the second lens group G2 is f2, and the focal length of the entire photographic lens ZL3 in the longest focal length state is fT. It is desirable to satisfy Formula (5).

0.09 <(− f2) / fT <0.20 (5)

  Conditional expression (5) is a conditional expression that defines the focal length of the second lens group G2 suitable for adjusting the manufacturing error by tilting the second lens group G2 with respect to the optical axis. When the upper limit of conditional expression (5) is exceeded, the refractive power of the second lens group G2 becomes small, the change in imaging performance with respect to the tilt of the second lens group G2 becomes small, and the second for adjusting manufacturing errors. This is not preferable because the tilt amount of the lens group G2 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (5) to 0.18. On the other hand, if the lower limit of conditional expression (5) is not reached, the refractive power of the second lens group G2 becomes large, and the change in imaging performance with respect to the tilt of the second lens group G2 becomes too sensitive, and adjustment of the manufacturing error. Therefore, when the second lens group G2 is tilted, highly accurate position adjustment is required. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.11.

  The photographic lens ZL3 according to the third embodiment has the following conditions when the focal length of the fourth lens group G4 is f4 and the focal length of the entire photographic lens ZL3 in the longest focal length state is fT. It is desirable to satisfy Formula (6).

0.40 <f4 / fT <0.78 (6)

  Conditional expression (6) is a conditional expression that defines the focal length of the fourth lens group G4 suitable for adjusting the manufacturing error by tilting the fourth lens group G4 with respect to the optical axis. When the upper limit of conditional expression (6) is exceeded, the refractive power of the fourth lens group G4 becomes small, the change in imaging performance with respect to the tilt of the fourth lens group G4 becomes small, and the fourth for adjusting manufacturing errors. This is not preferable because the tilt amount of the lens group G4 increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (6) to 0.72. On the other hand, if the lower limit value of conditional expression (6) is not reached, the refractive power of the fourth lens group G4 becomes large, and the change in the imaging performance with respect to the tilt of the fourth lens group G4 becomes too sensitive, and adjustment of the manufacturing error. Therefore, when the fourth lens group G4 is tilted, highly accurate position adjustment is required. This undesirably increases the time required for adjustment and increases the manufacturing cost. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.46.

  FIG. 22 is a schematic cross-sectional view of a digital single-lens reflex camera 1 (hereinafter simply referred to as a camera) as an imaging apparatus including the above-described photographing lens ZL. In this camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 (shooting lens ZL) and imaged on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected a plurality of times in the pentaprism 5 and guided to the eyepiece lens 6. Thus, the photographer can observe the object (subject) image as an erect image through the eyepiece 6.

  Further, when a release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light of an object (subject) (not shown) condensed by the photographing lens 2 is captured on the image sensor 7. Form an image. Thereby, the light from the object (subject) is captured by the image sensor 7 and recorded as an object (subject) image in a memory (not shown). In this way, the photographer can shoot an object (subject) with the camera 1. Note that the camera 1 shown in FIG. 22 may hold the photographic lens ZL in a removable manner, or may be formed integrally with the photographic lens ZL. The camera 1 may be a so-called single-lens reflex camera or a compact camera without a quick return mirror or the like.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1, FIG. 8, and FIG. 15 are cross-sectional views showing the lens configuration of the taking lens ZL (ZL1 to ZL3) according to the present embodiment. As shown in FIGS. 1 and 8, the photographing lenses ZL1 and ZL2 according to the first and second examples have a positive refractive power and a first lens group G1 having a positive refractive power in order from the object side. The lens unit includes a second lens group G2 and a third lens group G3 having negative refractive power. As shown in FIG. 15, the taking lens ZL3 according to the third example 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 positive The third lens group G3 having refracting power and the fourth lens group G4 having positive refracting power.

[First embodiment]
FIG. 1 is a lens configuration diagram of the taking lens ZL1 according to the first example. As shown in FIG. 1, in the lens configuration of the first example, the first lens group G1 includes, in order from the object side, a negative meniscus lens L101 having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side. It comprises a cemented negative lens L102, a biconvex lens L103, and a positive meniscus lens L104 having a convex surface facing the object side. The second lens group G2, in order from the object side, is a cemented positive lens composed of a negative meniscus lens L201 having a convex surface facing the object side, a biconcave lens L202 and a positive meniscus lens L203 having a convex surface facing the object side, and a concave surface facing the object side A negative meniscus lens L204 with a convex surface facing the object side, a cemented positive lens of a negative meniscus lens L205 with a convex surface facing the object side and a biconvex lens L206, a biconvex lens L207, a negative meniscus lens L208 with a concave surface facing the object side, an aperture stop S, A cemented positive lens composed of a negative meniscus lens L209 having a convex surface facing the object side and a biconvex lens L210, a cemented negative lens composed of a positive meniscus lens L211 having a concave surface facing the object side and a biconcave lens L212, and a negative lens having a convex surface facing the object side A cemented positive lens composed of a meniscus lens L213 and a biconvex lens L214, and a positive lens having a convex surface facing the object side. And a Sukasurenzu L215. The third lens group G3 includes a negative meniscus lens L301 having a concave surface directed toward the object side.

  2 to 4 are diagrams schematically showing the mechanism of the photographing lens ZL1 in the first embodiment, FIG. 2 is a cross-sectional view schematically showing the mechanism of the photographing lens ZL1, and FIG. 3 is a photographing lens. 4 is a plan view of ZL1 as viewed from the object side, and FIG. 4 is a plan view of photographic lens ZL1 as viewed from the image side. The reference numerals are common to FIGS.

  As shown in FIGS. 2 and 3, the first lens group G1 is held by an annular first holding member 41, the third lens group G3 is held by an annular second holding member 42, and the first holding member. 41 is fixed to the lens barrel member 43 by screws 44 and 45. The first holding member 41 is provided with holes (so-called “fool holes”, the same applies to the following embodiments) 41 a and screw holes 41 b at three locations, and the lens barrel member 43 has screw holes. 43a is provided in three places. The diameter of the hole 41a is formed larger than the shaft diameter of the screw 44, the screw hole 43a is formed so that the screw 44 can be screwed in, and the screw hole 41b is formed so that the screw 45 can be screwed in. With this configuration, the tilt of the first holding member 41 with respect to the lens barrel member 43 can be adjusted and fixed by tightening and loosening the screws 44 and 45. In other words, the first lens group G1 can be tilted with respect to the optical axis, and can be disposed at a position where the deterioration of the imaging performance due to the decentration error at the time of manufacture is satisfactorily corrected. it can. Note that the screw 44 and the screw 45 can be adjusted from the outside, and can be adjusted from the outside of the photographic lens ZL1 without disassembling the photographic lens ZL1.

  Further, as shown in FIGS. 2 and 4, the second holding member 42 is fixed to the lens barrel member 43 with a screw 46 through a washer 47. The second holding member 42 is provided with three holes 42a, and the lens barrel member 43 is provided with three screw holes 43b. Here, the three holes 42a are formed larger than the shaft diameter of the screw 46, and the screw hole 43b is formed so that the screw 46 can be screwed therein. With this configuration, the three screws 46 are loosened to adjust the position in the direction perpendicular to the optical axis of the second holding member 42 with respect to the lens barrel member 43, and then the screws 46 are tightened and fixed. That is, it is possible to shift the third lens group G3 in a direction perpendicular to the optical axis, and to place the third lens group G3 at a position where the deterioration of the imaging performance due to the decentration error at the time of manufacturing is satisfactorily corrected. Can be realized. The screw 46 is located at an adjustable position from the mount side, and can be adjusted from the mount side of the photographic lens ZL1 without disassembling the photographic lens ZL1.

  In the first embodiment, the air gap between the second lens group G2 and the third lens group G3 can be changed by replacing the washer 47 with a washer having a different thickness in the optical axis direction. It is also possible to correct changes in spherical aberration or curvature of field caused by manufacturing errors such as curvature, lens thickness, lens interval, and lens refractive index.

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents the focal length, FNO represents the F number, and 2ω represents the angle of view. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the refractive index and Abbe number are each The value for the d-line (λ = 587.6 nm) is shown. Here, “mm” is generally used for the focal length, the radius of curvature, the surface interval, and other length units listed in all the following specifications, but the optical system is proportionally enlarged or reduced. However, the same optical performance can be obtained, and the present invention is not limited to this. The curvature radius ∞ indicates a plane, and the refractive index of air 1.000 is omitted. The description of these symbols and the description of the specification table are the same in the following embodiments.

(Table 1)
Wide angle end Telephoto end
f = 71.4 to 196.0
FNO = 2.91 to 2.91
2ω = 34.2 ° ~ 12.3 °

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 207.2519 2.0000 32.35 1.850 260
2 77.5141 9.5000 82.52 1.497820
3 461.0795 0.1000
4 96.8810 8.0000 82.52 1.497820
5 -2446.3946 0.1000
6 74.8396 8.0000 65.46 1.603001
7 635.5296 (d1)
8 301.7367 2.2000 42.72 1.834807
9 35.0104 9.1179
10 -83.6050 2.0000 70.41 1.487490
11 42.3925 6.0000 23.78 1.846660
12 647.2222 4.5999
13 -49.2733 2.2000 65.46 1.603001
14 -2747.7138 (d2)
15 350.7655 2.0000 28.46 1.728250
16 91.4253 6.5000 65.46 1.603001
17 -94.5881 0.1000
18 143.9361 5.5000 65.46 1.603001
19 -132.9507 (d3)
20 -84.4304 2.5000 52.31 1.754999
21 -211.8686 (d4)
22 ∞ 1.0000 (Aperture stop S)
23 44.5401 2.0000 32.35 1.850 260
24 30.5381 9.0000 65.46 1.603001
25 -8165.2768 25.0000
26 -197.5962 4.0000 32.35 1.850260
27 -34.4924 2.0000 54.66 1.729157
28 47.2773 5.0000
29 147.5802 2.0000 32.35 1.850 260
30 52.0642 6.0000 82.52 1.497820
31 -60.9696 0.1000
32 37.8007 6.0000 82.52 1.497820
33 394.5473 5.0000
34 -47.6819 2.0000 44.88 1.639300
35 -113.6656 58.1161

  In the first embodiment, when zooming from the shortest focal length state to the longest focal length state, the air gap d1 between the first lens group G1 and the second lens group G2, and the negative meniscus lens L204 of the second lens group G2. The focal distance is changed by changing the air gap d2 between the negative meniscus lens L205, the air gap d3 between the biconvex lens L207 and the negative meniscus lens L208, and the air gap d4 between the negative meniscus lens L208 and the aperture stop S. . Table 2 below shows variable intervals at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 2)
Wide angle end Intermediate focal length Telephoto end f 71.40002 135.00011 196.00033
d1 1.99999 23.00070 30.81585
d2 29.81608 15.62605 2.94345
d3 6.61715 14.91938 19.78683
d4 17.11292 2.00000 2.00000

  Table 3 below shows corresponding values of the conditional expressions (1) and (2) in the first embodiment. The definition of each variable in Table 3 is as described in the description of conditional expressions (1) and (2).

(Table 3)
(1) f1 / fT = 0.471
(2) (−f3) /fT=0.663

  Here, in the photographic lens ZL1 according to the first example, the deterioration of the imaging performance due to the decentration error at the time of manufacturing is corrected, and a state in which good optical performance is achieved is shown in the photographic lens ZL1 according to the first example. A description will be given using the longest focal length state as an example.

  FIG. 5 is a diagram showing transverse aberration with respect to the d-line (λ = 587.6 nm) in the longest focal length state of the taking lens ZL1 according to the first example when no decentering error occurred during manufacturing. 5A shows lateral aberration with respect to an image height of 15 mm, FIG. 5B shows lateral aberration with respect to an image height of 0 mm (center), and FIG. 5C shows lateral aberration with respect to an image height of −15 mm. FIG. 6 is a diagram showing transverse aberration in the longest focal length state of the taking lens ZL1 according to the first example when a predetermined decentering error occurs at the time of manufacture. FIG. 6 (a) shows transverse aberration with respect to an image height of 15 mm. FIG. 6B shows lateral aberration with respect to an image height of 0 mm (center), and FIG. 6C shows lateral aberration with respect to an image height of −15 mm.

  FIG. 7 shows a state in which the first lens group G1 is tilted by −1 ′ and the third lens group G3 is shifted by −0.15 mm from the state where a predetermined eccentricity error has occurred at the time of manufacture using the adjustment mechanism described above. FIGS. 7A and 7B are diagrams illustrating lateral aberration in the longest focal length state of the taking lens ZL1 according to the first example. FIG. 7A illustrates lateral aberration with respect to an image height of 15 mm, and FIG. ), And FIG. 7C shows the lateral aberration with respect to an image height of −15 mm. From FIG. 7, when adjustment is performed by tilting the first lens group G1 and shifting the third lens group G3, the decentration aberration is corrected well, and the imaging performance at the center and the periphery is improved. You can see that

  As described above, the photographic lens ZL1 according to the first example can achieve a good optical performance by correcting the decentration error generated at the time of manufacture.

[Second Embodiment]
FIG. 8 is a lens configuration diagram of the taking lens ZL2 according to the second example. As shown in FIG. 8, in the lens configuration of the second example, the first lens group G1 includes, in order from the object side, a cemented negative lens composed of a negative meniscus lens L101 having a convex surface facing the object side and a biconvex lens L102, The lens includes a convex lens L103 and a positive meniscus lens L104 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L201 having a convex surface facing the object side, a cemented positive lens composed of a biconcave lens L202 and a positive meniscus lens 203 having a convex surface facing the object side, and a concave surface facing the object side. A negative meniscus lens L205 having a concave surface facing the object side, a positive meniscus lens L206 having a concave surface facing the object side, a negative meniscus lens L207 having a convex surface facing the object side, and a biconvex lens A cemented positive lens with L208, a negative meniscus lens L209 with a concave surface facing the object side, a biconvex lens L210, a positive meniscus lens L211 with a convex surface facing the object side, an aperture stop S, a negative cemented lens with a biconvex lens L212 and a biconcave lens L213 A lens, a negative meniscus lens L214 having a convex surface facing the object side, a biconvex lens L215, and And a biconvex lens L216. The third lens group G3 includes a negative meniscus lens L301 having a concave surface directed toward the object side.

  FIGS. 9 to 11 are diagrams schematically showing the mechanism of the taking lens ZL2 in the second embodiment. FIG. 9 is a cross-sectional view of the taking lens ZL2, and FIG. 10 is a plan view of the taking lens ZL2 as viewed from the object side. FIG. 11 is a plan view of the photographic lens ZL2 as viewed from the image side. The reference numerals are common to FIGS.

  As shown in FIGS. 9 and 10, the first lens group G1 is held by an annular first holding member 51, and the third lens group G3 is held by an annular second holding member 52. 51 is fixed to the barrel member 53 with a screw 54 via a washer 55. The first holding member 51 is provided with three holes 51a, and the lens barrel member 53 is provided with three screw holes 53a. The diameter of the hole 51a is formed larger than the shaft diameter of the screw 54, and the screw hole 53a is formed so that the screw 54 can be screwed. With this configuration, the screws 54 are loosened to adjust the position in the direction perpendicular to the optical axis of the first holding member 51 with respect to the lens barrel member 53, and then the screws 54 are tightened and fixed. That is, it is possible to shift the first lens group G1 in a direction perpendicular to the optical axis and arrange it at a position that favorably corrects the deterioration in imaging performance due to decentration error during manufacturing, and good correction of decentration aberrations. Can be realized. The screw 54 is adjustable from the outside, and can be adjusted from the outside of the photographic lens ZL2 without disassembling the photographic lens ZL2.

  In the second embodiment, the air gap between the first lens group G1 and the second lens group G2 can be changed by replacing the washer 55 with a washer having a different thickness in the optical axis direction. It is also possible to correct a change in back focus caused by manufacturing errors such as curvature, lens thickness, lens interval, and lens refractive index.

  Further, as shown in FIGS. 9 and 11, the second holding member 52 is fixed to the lens barrel member 53 with a screw 56 via a washer 57. The second holding member 52 is provided with three holes 52a, and the lens barrel member 53 is provided with three screw holes 53b. Here, the three holes 52a are formed larger than the shaft diameter of the screw 56, and the screw hole 53b is formed so that the screw 56 can be screwed therein. With this configuration, the three screws 56 are loosened to adjust the position in the direction perpendicular to the optical axis of the second holding member 52 with respect to the lens barrel member 53, and then the screws 56 are tightened and fixed. That is, it is possible to shift the third lens group G3 in a direction perpendicular to the optical axis, and to place the third lens group G3 at a position where the deterioration of the imaging performance due to the decentration error at the time of manufacturing is satisfactorily corrected. Can be realized. The screw 56 is adjustable from the mount side and can be adjusted from the mount side of the photographic lens ZL2 without disassembling the photographic lens ZL2.

  In the second embodiment, the air gap between the second lens group G2 and the third lens group G3 can be changed by replacing the washer 57 with a washer having a different thickness in the optical axis direction. It is also possible to correct changes in spherical aberration or curvature of field caused by manufacturing errors such as curvature, lens thickness, lens interval, and lens refractive index.

  Table 4 below lists values of specifications of the second embodiment.

(Table 4)
Wide angle end Telephoto end
f = 71.4 to 196.0
FNO = 2.89 to 2.89
2ω = 33.9 ° to 12.2 °

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 381.3020 2.5000 28.69 1.795041
2 106.4250 8.8000 82.52 1.497820
3 -1149.1256 0.1000
4 98.2127 8.5000 82.52 1.497820
5 -1919.4180 0.1000
6 66.6347 8.5000 82.52 1.497820
7 293.0617 (d1)
8 228.7827 2.1000 46.62 1.816000
9 33.2041 10.0000
10 -117.4258 2.1000 70.41 1.487490
11 37.9960 6.2000 23.78 1.846660
12 287.5696 4.2000
13 -53.8038 3.3000 25.43 1.805181
14 -38.9730 2.1000 46.62 1.816000
15 -2687.3318 (d2)
16 -1365.0388 3.8000 44.78 1.743997
17 -93.5331 0.1000
18 77.7004 2.4000 23.78 1.846660
19 47.7610 8.8000 65.46 1.603001
20 -130.8829 (d3)
21 -90.0052 2.5000 23.78 1.846660
22 -222.5672 (d4)
23 156.5810 3.8000 82.52 1.497820
24 -223.4996 0.1000
25 48.3764 4.0000 82.52 1.497820
26 104.4479 6.6000
27 ∞ 15.4000 (Aperture stop S)
28 629.9782 3.8000 28.46 1.728250
29 -55.4480 1.6000 53.71 1.579570
30 55.4345 4.0000
31 482.0258 1.6000 39.57 1.804400
32 58.8315 4.0000
33 182.5454 5.0000 82.52 1.497820
34 -61.2108 0.1000
35 40.0944 6.5000 82.52 1.497820
36 -880.4337 4.7500
37 -53.2131 2.0000 32.35 1.850 260
38 -148.8412 53.7873

  In the second embodiment, when zooming from the shortest focal length state to the longest focal length state, the air gap d1 between the first lens group G1 and the second lens group G2, and the negative meniscus lens L205 of the second lens group G2. The focal distance is changed by changing the air distance d2 between the positive meniscus lens L206, the air distance d3 between the biconvex lens L208 and the negative meniscus lens L209, and the air distance d4 between the negative meniscus lens L209 and the biconvex lens L210. Table 5 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 5)
Wide angle end Intermediate focal length Telephoto end f 71.40001 105.00008 195.99998
d1 2.05398 16.41142 30.77623
d2 25.89558 19.01839 2.01055
d3 5.28887 8.92163 16.87079
d4 19.89903 8.78601 3.47988

  Table 6 below shows corresponding values of the conditional expressions (3) and (4) in the second embodiment. The definition of each variable in Table 6 is as described in the description of conditional expressions (3) and (4) above.

(Table 6)
(3) f1 / fT = 0.472
(4) (−f3) /fT=0.502

  Here, in the photographic lens ZL2 according to the second example, the deterioration of the imaging performance due to the decentration error at the time of manufacture is corrected, and a state in which good optical performance is achieved is shown in the photographic lens ZL2 according to the second example. A description will be given using the longest focal length state as an example.

  FIG. 12 is a diagram showing transverse aberration with respect to the d-line (λ = 587.6 nm) in the longest focal length state of the taking lens ZL2 according to Example 2 when no eccentric error occurs during manufacturing. 12 (a) shows the lateral aberration for an image height of 15 mm, FIG. 12 (b) shows the lateral aberration for an image height of 0 mm (center), and FIG. 12 (c) shows the lateral aberration for an image height of −15 mm. FIG. 13 is a diagram showing lateral aberration in the longest focal length state of the taking lens ZL2 according to the second example when a predetermined decentering error occurs at the time of manufacture. FIG. 13 (a) shows lateral aberration with respect to an image height of 15 mm. FIG. 13B shows lateral aberration with respect to an image height of 0 mm (center), and FIG. 13C shows lateral aberration with respect to an image height of −15 mm.

  FIG. 14 shows a state in which the first lens group G1 is shifted by +0.12 mm and the third lens group G3 is shifted by −0.10 mm from the state where a predetermined eccentricity error has occurred at the time of manufacture using the adjustment mechanism described above. FIGS. 14A and 14B show lateral aberrations in the longest focal length state of the taking lens ZL2 according to the second example, FIG. 14A shows lateral aberrations with respect to an image height of 15 mm, and FIG. 14B shows image heights of 0 mm (center). ), And FIG. 14C shows the lateral aberration with respect to an image height of −15 mm. From FIG. 14, when the adjustment is performed by shifting the first lens group G1 and the third lens group G3, the decentration aberration is corrected well, and the imaging performance of the center and the periphery is improved. I understand that.

  As described above, the photographic lens ZL2 according to the second example can achieve good optical performance by correcting the decentration error generated at the time of manufacture.

[Third embodiment]
FIG. 15 is a lens configuration diagram of the taking lens ZL3 according to the third example. As shown in FIG. 15, in the lens configuration of the third example, the first lens group G1 includes, in order from the object side, a negative meniscus lens L101 having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side. The lens includes a positive lens cemented with L102, a positive meniscus lens L103 having a convex surface facing the object side, and a positive meniscus lens L104 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L201 having a convex surface facing the object side, a cemented negative lens of a biconcave lens L202 and a positive meniscus lens L203 having a convex surface facing the object side, and the object side. It is composed of a cemented negative lens composed of a positive meniscus lens L204 having a concave surface and a negative meniscus lens L205 having a concave surface facing the object side. The third lens group G3 includes a cemented positive lens composed of a negative meniscus lens L301 having a convex surface directed toward the object side and a biconvex lens L302, a biconvex lens L303, and a negative meniscus lens L304 having a concave surface directed toward the object side. . The fourth lens group G4 includes a cemented positive lens composed of a biconvex lens L401 and a biconcave lens L402, an aperture stop S, a cemented negative lens composed of a positive meniscus lens L403 having a concave surface facing the object side, and a biconcave lens L404, and a convex surface facing the object side. A negative positive meniscus lens L405 and a biconvex lens L406, a biconvex lens L407, and a negative meniscus lens L408 having a concave surface facing the object side.

  FIGS. 16 to 18 are diagrams schematically showing the mechanism of the taking lens ZL3 in the third embodiment, FIG. 16 is a sectional view of the taking lens ZL3, and FIG. 17 is a view of the taking lens ZL3 from the image side. A plan view is shown. FIG. 18 is a diagram schematically showing the configuration of the first holding member 61 from the oblique direction on the object side. The reference numerals are common to FIGS.

  As shown in FIGS. 16 and 17, the second lens group G <b> 2 is held by an annular first holding member 61 having a double structure, and the first holding member 61 is engaged with a cam member 64 by a cam pin 66. Yes. The fourth lens group G4 is held by an annular second holding member 62, and the second holding member 62 is fixed to the barrel member 63 by screws 67 and 68. The second holding member 62 is provided with three holes 62a and screw holes 62b, and the lens barrel member 63 is provided with three screw holes 63b. The diameter of the hole 62a is formed larger than the shaft diameter of the screw 67, the screw hole 63b is formed so that the screw 67 can be screwed in, and the screw hole 62b is formed so that the screw 68 can be screwed in. With this configuration, the tilt of the second holding member 62 with respect to the lens barrel member 63 can be adjusted and fixed by tightening and loosening the screws 67 and 68. That is, the fourth lens group G4 can be tilted with respect to the optical axis, and can be disposed at a position where the deterioration of the imaging performance due to the decentration error at the time of manufacture is favorably corrected, thereby realizing good correction of the decentration aberration. it can. The screw 67 and the screw 68 are adjustable from the mount side, and can be adjusted from the mount side of the photographic lens ZL3 without disassembling the photographic lens ZL3.

  As shown in FIG. 18, the first holding member 61 has a double ring structure, and the second lens group G2 is held by the inner ring part 61a, and the inner ring part 61a. And the outer annular portion 61b are connected by three connecting portions 61c. A cam pin 66 is fixed to the outer annular portion 61 b and is engaged with the cam member 64 via the cam pin 66. The outer annular portion 61b is provided with three grooves 61d. By screwing the immobilizer 65 into the groove 61d, the outer annular portion 61b is deformed and the inner annular portion 61a is tilted. it can. The lens barrel member 63 is provided with three holes 63a, and a hex key wrench (not shown) can be inserted through the hole 63a to allow the immobilizer 65 to be screwed. With this configuration, the second lens group G2 is tilted with respect to the optical axis by tightening the three immobilizers 65, and is disposed at a position that favorably corrects deterioration in imaging performance due to decentration error during manufacturing. Therefore, it is possible to achieve a good correction of decentration aberration. Further, as described above, the immobilizer 65 can be adjusted from the outside of the lens barrel member 63 and can be adjusted from the outside of the photographic lens ZL3 without disassembling the photographic lens ZL3.

  Table 7 below lists values of specifications of the third example.

(Table 7)
Wide angle end Telephoto end
f = 71.4 to 196.0
FNO = 2.91 to 2.91
2ω = 34.2 ° ~ 12.3 °

Surface number Curvature radius Surface spacing Abbe number Refractive index
1 138.9420 2.0000 32.35 1.850 260
2 74.8515 10.0000 82.52 1.497820
3 499.1083 0.1000
4 86.7613 8.0000 82.52 1.497820
5 437.0393 0.1000
6 84.2569 7.0000 82.52 1.497820
7 938.7139 (d1)
8 384.1157 2.0000 40.94 1.806100
9 35.6165 9.6847
10 -131.1744 2.0000 70.41 1.487490
11 42.3484 4.5000 23.78 1.846660
12 163.1687 5.0588
13 -53.5772 4.0000 22.76 1.808095
14 -32.5969 2.0000 42.72 1.834807
15 -234.9579 (d2)
16 510.9139 2.0000 32.35 1.850 260
17 86.7071 7.0000 65.46 1.603001
18 -83.2647 0.1000
19 103.7337 6.0000 65.46 1.603001
20 -116.8560 (d3)
21 -103.1415 2.5000 42.72 1.834807
22 -342.0133 (d4)
23 58.8589 7.0000 42.72 1.834807
24 -140.2358 2.0000 23.78 1.846660
25 198.9539 3.0000
26 ∞ 20.0000 (Aperture stop S)
27 -183.3956 4.0000 23.78 1.846660
28 -45.0249 2.0000 41.96 1.667551
29 57.8421 5.0000
30 383.3560 2.0000 50.23 1.719995
31 39.1251 7.0000 82.52 1.497820
32 -82.1158 0.1000
33 45.2987 7.0000 82.52 1.497820
34 -153.4974 7.5493
35 -47.9028 2.0000 32.35 1.850260
36 -82.5403 63.5393

  In the third embodiment, when zooming from the shortest focal length state to the longest focal length state, the air gap d1 between the first lens group G1 and the second lens group G2, the second lens group G2 and the third lens group. By changing the air gap d2 with G3, the air gap d3 between the biconvex lens L303 and the negative meniscus lens L304 of the third lens group G3, and the air gap d4 between the third lens group G3 and the fourth lens group G4. Change the focal length. Table 8 below shows variable intervals at the respective focal lengths in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

(Table 8)
Wide angle end Intermediate focal length Telephoto end f 71.40012 135.00026 196.00046
d1 2.00000 25.43704 33.99476
d2 24.32992 12.56574 2.00000
d3 4.66795 10.86541 14.95333
d4 21.95021 4.07989 2.00000

  Table 9 below shows corresponding values of the conditional expressions (5) and (6) in the third embodiment. The definition of each variable in Table 9 is as described in the description of conditional expressions (5) and (6) above.

(Table 9)
(5) (−f2) /fT=0.136
(6) f4 / fT = 0.582

  Here, in the photographic lens ZL3 according to the third example, the deterioration of the imaging performance due to the decentration error at the time of manufacture is corrected, and a state in which good optical performance is achieved is shown in the photographic lens ZL3 according to the third example. A description will be given using the longest focal length state as an example.

  FIG. 19 is a diagram showing transverse aberration with respect to the d-line (λ = 587.6 nm) in the longest focal length state of the taking lens ZL3 according to Example 3 when no decentering error occurs during manufacturing. 19 (a) shows lateral aberration with respect to an image height of 15 mm, FIG. 19 (b) shows lateral aberration with respect to an image height of 0 mm (center), and (c) shows lateral aberration with respect to an image height of −15 mm. FIG. 20 is a diagram showing lateral aberration in the longest focal length state of the taking lens ZL3 according to Example 3 when a predetermined decentering error occurs during manufacturing, and FIG. 20 (a) shows lateral aberration with respect to an image height of 15 mm. FIG. 20B shows lateral aberration with respect to an image height of 0 mm (center), and FIG. 20C shows lateral aberration with respect to an image height of −15 mm.

FIG. 21 shows the third state when the second lens group G2 is tilted by +4 ′ and the fourth lens group G4 is tilted by +13 ′ from the state where a predetermined eccentricity error has occurred during manufacturing, using the adjustment mechanism described above. FIGS. 21A and 21B are diagrams illustrating lateral aberrations in the longest focal length state of the photographing lens ZL3 according to the example. FIG. 21A illustrates lateral aberrations with respect to an image height of 15 mm, and FIG. 21B illustrates lateral aberrations with respect to an image height of 0 mm (center). FIG. 21C shows the aberrations with respect to the image height of −15 mm. From FIG. 21, when the adjustment is performed by tilting the second lens group G2 and the fourth lens group G4, the decentration aberration is corrected well, and the center and peripheral imaging performance are improved. I understand that.

  As described above, the photographic lens ZL3 according to the third example can achieve good optical performance by correcting the decentration error generated at the time of manufacture.

  As is clear from the above, the photographic lens ZL according to the first to third examples can realize a good optical performance by correcting the eccentric error generated at the time of manufacture. Therefore, it is possible to provide a low-cost photographing lens ZL that can achieve good optical performance and a method for adjusting the photographing lens ZL.

  In each of the above embodiments, the configuration in which the lens group is divided into three or four lens groups at the time of zooming is shown, but the present invention can also be applied to other group configurations such as a fifth group and a sixth group. Further, a configuration in which a lens or a lens group is added to the most object side, or a configuration in which a lens or a lens group is added to the most image side may be used. The lens group indicates a portion having at least one lens.

  A single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. In this case, the focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor).

  In addition, the lens group or the partial lens group is moved so as to have a component in a direction perpendicular to the optical axis, or is rotated (swayed) in the in-plane direction including the optical axis to reduce image blur caused by camera shake. A vibration-proof lens group to be corrected may be used.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric surface. It is preferable that the lens surface is a spherical surface or a flat surface because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in processing and assembly adjustment is prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. When the lens surface is an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. Any aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably arranged in the second lens group G2 or the fourth lens group G4. However, the role of the aperture stop may be substituted by a lens frame without providing a member as an aperture stop. .

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

ZL (ZL1 to ZL3) Shooting lens G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group S Aperture stop 1 Electronic still camera (optical equipment)

Claims (20)

From the object side,
A first lens group having a positive refractive power;
A second lens group having a positive refractive power;
A third lens group having negative refractive power,
An imaging lens having a structure in which the first lens group can be tilted with respect to an optical axis and the third lens group can be shifted in a direction perpendicular to the optical axis. From the object side,
A first lens group having a positive refractive power;
A second lens group having a positive refractive power;
A third lens group having negative refractive power,
A photographic lens having a structure capable of shifting the first lens group and the third lens group in a direction perpendicular to the optical axis.   The photographic lens according to claim 1, wherein the third lens group includes a negative meniscus lens having a concave surface facing the object side.   The photographing lens according to any one of claims 1 to 3, wherein the first lens group includes one or more positive lenses and one or more negative lenses.   The photographic lens according to claim 4, wherein the first lens group includes two or more positive lenses and one or more negative lenses.   The said 2nd lens group contains at least 1 variable air space | interval, and changes a focal distance by changing this air space | interval, when zooming from the shortest focal length state to the longest focal length state. The taking lens according to claim 1.   The focal length is changed by changing an air gap between the first lens group and the second lens group when zooming from the shortest focal length state to the longest focal length state. The described taking lens. When the focal length of the first lens group is f1, and the focal length of the entire system in the longest focal length state is fT, the following expression 0.30 <f1 / fT <0.65
The photographic lens according to claim 1, which satisfies the following condition. When the focal length of the third lens group is f3 and the focal length of the entire system in the longest focal length state is fT, the following expression 0.30 <(− f3) / fT <0.85
The photographic lens according to claim 1, which satisfies the following condition. From the object side,
A first lens group having a positive refractive power;
A second lens group having negative refractive power;
A third lens group having positive refractive power;
A fourth lens group having a positive refractive power,
A photographic lens having a structure in which the second lens group and the fourth lens group can be tilted with respect to an optical axis.   The photographing lens according to claim 10, wherein the second lens group includes one or more positive lenses and two or more negative lenses.   When zooming from the shortest focal length state to the longest focal length state, the air gap between the first lens group and the second lens group and the air gap between the second lens group and the third lens group are set. The photographic lens according to claim 10, wherein the focal length is changed by changing the focal length.   The photographing lens according to claim 12, wherein, when zooming from the shortest focal length state to the longest focal length state, the focal length is further changed by changing an air interval between the third lens group and the fourth lens group. .   The third lens group includes at least one variable air interval, and changes the focal length by changing the air interval when zooming from the shortest focal length state to the longest focal length state. The taking lens according to claim 1. When the focal length of the second lens group is f2, and the focal length of the entire system in the longest focal length state is fT, the following expression 0.09 <(− f2) / fT <0.20
The photographic lens according to claim 10, which satisfies the following condition. When the focal length of the fourth lens group is f4 and the focal length of the entire system in the longest focal length state is fT, the following formula 0.40 <f4 / fT <0.78
The photographic lens according to claim 10, which satisfies the following condition.   The imaging device provided with the imaging lens as described in any one of Claims 1-16. A method for adjusting a photographic lens, which includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. And
A method for adjusting a photographing lens, wherein the first lens group is tilted with respect to an optical axis, and the third lens group is shifted in a direction orthogonal to the optical axis. A method for adjusting a photographic lens, which includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. And
A method for adjusting a photographic lens, wherein the first lens group and the third lens group are shifted in a direction perpendicular to the optical axis. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power A method for adjusting a photographic lens comprising:
A method for adjusting a photographing lens in which the second lens group and the fourth lens group are tilted with respect to an optical axis.

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