JP6576142B2 - Imaging apparatus and imaging system - Google Patents

Description

The present invention relates to an imaging apparatus and an imaging system.

Conventionally, to place the optical system, to change the focal length of the entire the focal length of the photographing optical system approach between the photographing optical system (main lens system) and the imaging device have been proposed. For example, Patent Document 1, the imaging apparatus has been proposed that to have the optical system you increase the focal length in the imaging device. In Patent Document 2, by inserting between the interchangeable lens and the imaging apparatus is an imaging optical system, attachment to obtain a focal length than has long focal length of the interchangeable lens has been proposed.

JP 2000-19613 A JP-A-11-258499

In recent years, imaging devices such as television cameras, movie cameras, photographic cameras, video cameras, and the like have been desired to achieve both high pixels and high sensitivity, and imaging devices having large-size imaging elements are required. Yes. On the other hand, there is a demand for users to use existing interchangeable lens assets. For this reason, for example, there is a strong need to use a 2/3 inch format interchangeable lens for an image pickup apparatus of a super 35 mm format having a larger image pickup device. In this case, between the interchangeable lens and the imaging device, obtained Ru optics focal length not longer than the focal length of the interchangeable lens are arranged, it is necessary to enlarge the image circle of the interchangeable lens.

However, the imaging apparatus of Patent Document 1 does not have a configuration in which an imaging optical system (main lens system) is provided integrally with the imaging apparatus and an interchangeable lens can be attached. In the attachment of Patent Document 2 , the distance from the interchangeable lens to the imaging device is increased, and the imaging system is increased in size.

The present invention is, for example, and an object thereof is to provide a favorable image pickup apparatus for obtaining a focal length not longer than the focal length of the interchangeable lens mounted.

To achieve the above object, an imaging apparatus of the present invention, between the mount you mount the interchangeable lens, an optical system, an imaging apparatus having an imaging element, a and the optical system and the imaging device has an optical filter, the optical system has a refractive power, the object point located on the image side of the most object side surface of the optical system is imaged on the image pickup device, the optical system in, The optical system includes a negative lens, a negative lens, and a positive lens in order from the object side to the image side, or a negative lens, a positive lens, and a negative lens in order from the object side to the image side. From the most object side lens to the third lens from the object side of the optical system as the first lens group, and the average refractive index of the negative lens constituting the first lens group as nav, the first lens group The average Abbe number of the negative lenses constituting νn is νn, and the first lens group is constructed. The Abbe number of the positive lens as vp,
1.8 <nav
5 <νn−νp <20
The following conditional expression is satisfied .

According to the present invention, for example, Ru can provide advantageous imaging apparatus for obtaining a long have focal than the focal length of the interchangeable lens mounted.

Basic configuration diagram of Embodiment 1 Cross-sectional view of the lens when focusing on infinity at the wide-angle end of the interchangeable lens Longitudinal aberration diagram when focusing on infinity at the wide-angle end of an interchangeable lens Sectional view of the lens with an interchangeable lens attached to the image pickup apparatus of Embodiment 1 Longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end with the interchangeable lens attached to the image pickup apparatus of Example 1 Lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of Embodiment 2 Longitudinal aberration diagram when the interchangeable lens is mounted on the image pickup apparatus of Example 2 and the interchangeable lens is focused at infinity at the wide-angle end Lens cross-sectional view in a state where an interchangeable lens is attached to the image pickup apparatus of Embodiment 3 Longitudinal aberration diagram when the interchangeable lens is mounted on the image pickup apparatus of Example 3 and the interchangeable lens is focused at infinity at the wide-angle end Lens sectional view of the imaging device of Example 4 with an interchangeable lens mounted Longitudinal aberration diagram when the interchangeable lens is mounted on the image pickup apparatus of Example 4 and the interchangeable lens is focused at infinity at the wide angle end Cross-sectional view of a lens with an interchangeable lens attached to the image pickup apparatus of Embodiment 5 Longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end with the interchangeable lens attached to the image pickup apparatus of Example 5 Cross-sectional view of a lens with an interchangeable lens attached to the image pickup apparatus of Embodiment 6 Longitudinal aberration diagram when the interchangeable lens is mounted on the image pickup apparatus of Example 6 and the interchangeable lens is focused at infinity at the wide angle end Lens cross-sectional view with an interchangeable lens attached to the image pickup apparatus of Embodiment 7 Longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end with the interchangeable lens attached to the image pickup apparatus of Example 7 Basic configuration diagram of embodiment 8 Basic configuration diagram of Embodiment 9 Basic configuration diagram of 3-plate camera

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a basic configuration diagram of Embodiment 1 of the present invention. The imaging apparatus 101 of the present invention has a mount 104 on which an optical system 102, an imaging element 103, and an interchangeable lens can be attached. The optical system 102 forms an image on the image sensor 103 with respect to an object point 105 located on the image side of the most object side surface of the optical system 102. The object point 105 is an imaging point of the interchangeable lens when the interchangeable lens is mounted on the mount 104 and the image side of the interchangeable lens is air. In other words, the optical system 102 forms an image of the imaging point of the interchangeable lens (the object point of the optical system 102) on the image sensor 103. The optical system 102 has a refractive power, makes the focal length of the interchangeable lens longer, and enlarges the image circle of the interchangeable lens. Furthermore, the imaging apparatus of the present invention is characterized in that an optical filter 106 is disposed between the optical system 102 and the imaging element 103.

  Next, the arrangement of the optical system 102 will be described. In the present invention, the optical system 102 is built in the image pickup apparatus 101 and arranged to achieve downsizing of the photographing system. Here, it is considered that the optical system of the present invention is arranged instead of the color separation optical system for a three-plate camera using the color separation optical system, such as an image pickup apparatus compatible with the 2/3 inch format. FIG. 20 shows a general configuration diagram of a three-plate camera, and the three-plate camera 201 includes a color separation optical system 202, image sensors 203, 204, 205, and a mount 206. The optical system of the present invention is designed to have a size close to that of the color separation optical system 202 of the three-plate camera 201, and the optical system of the present invention is arranged instead of the color separation optical system. The shooting system using the camera has the same size as the 2/3 inch format shooting system. Therefore, the size of the photographing system can be reduced as compared with the case where an external attachment is inserted between the interchangeable lens and the imaging device.

  Furthermore, in the imaging apparatus of the present invention, the optical system 102 is disposed on the image side with respect to the mount 104. With such an arrangement, it is possible to prevent interference between the interchangeable lens and the optical system 102 when the interchangeable lens is attached to the imaging apparatus 101.

Further, in the image pickup apparatus of the present invention, an interchangeable lens is attached to the image pickup apparatus 101, and the image pickup element 103 is in focus (the object point 105 on the image side from the most object side surface of the optical system 102 is placed on the image pickup element. When the horizontal magnification of the optical system 102 in the state of imaging) is β, the image circle of the interchangeable lens is IC, and the diagonal length of the image sensor 103 is I,
0.8 <IC × β / I <1.3 (1)
It is characterized by satisfying. Here, the image circle IC of the interchangeable lens is defined as the diagonal length of the image sensor of the camera to which the interchangeable lens originally corresponds. For example, in an interchangeable lens for a 2/3 inch format, the image circle IC is 11 mm.

By satisfying the expression (1), both the downsizing of the image pickup apparatus and the securing of the image size for the image pickup element are achieved. If the upper limit of the expression (1) is not satisfied, the magnification ratio of the image circle of the interchangeable lens increases with respect to the size of the image sensor 103, and the optical system 102 increases in size. As a result, it is difficult to reduce the size of the imaging device 101. If the lower limit of the expression (1) is not satisfied, the enlargement ratio of the image circle of the interchangeable lens is small and vignetting occurs with respect to the image sensor 103, so that the peripheral portion of the screen becomes dark. More preferably, the formula (1) is set as follows.
0.95 <IC × β / I <1.15 (1a)

Further, the imaging apparatus of the present invention is configured such that the air-converted flange back of the interchangeable lens (the distance from the mount to the object point 105 on the image side from the most object side surface of the optical system 102) is FB, and the imaging element from the flange surface of the mount. When the distance on the optical axis to L is
1.0 <L / FB <3.0 (2)
1.0 <β <3.0 (3)
It is characterized by satisfying. By satisfying the expressions (2) and (3), both the miniaturization of the imaging device 101 and the high optical performance in the state where the image size of the interchangeable lens is enlarged are achieved. If the upper limit of the expression (2) is not satisfied, the distance from the interchangeable lens to the image sensor 103 becomes long, so that it is difficult to reduce the size of the image pickup apparatus 101. If the lower limit of the expression (2) is not satisfied, the distance from the interchangeable lens to the image sensor 103 is short, which is advantageous for downsizing the image pickup apparatus 101. However, since the length of the optical system 102 is short, the optical system 102 is configured. The refractive power of the lens becomes strong, making it difficult to achieve high optical performance. If the upper limit of the expression (3) is not satisfied, the lateral magnification of the optical system 102 is increased, and the optical system 102 is increased in size. As a result, it is difficult to reduce the size of the imaging device 101. If the lower limit of the expression (3) is not satisfied, the lateral magnification of the optical system 102 is less than 1, so that the image size of the interchangeable lens is not enlarged. More preferably, the equations (2) and (3) are set as follows.
1.2 <L / FB <2.0 (2a)
1.2 <β <2.2 (3a)
More preferably, the equations (2) and (3) are set as follows.
1.2 <L / FB <1.8 (2b)
1.20 <β <1.45 (3b)

Further, when the optical system 102 is divided into a front group on the object side and a rear group on the image side with a maximum air space in the optical system 102, the front group has a negative refractive power. When the focal length of the front group is ff and the focal length of the optical system 102 is fcv,
| Ff / fcv | <1.5 (4)
It is characterized by satisfying. By satisfying the expression (4), it is possible to appropriately secure the interval between the optical system 102 and the image sensor 103. If the expression (4) is not satisfied, the negative refractive power of the front group becomes weaker than the refractive power of the optical system, so that the back focus of the optical system is shortened, and the distance between the optical system and the image sensor is narrowed. For this reason, the lens on the most image side of the optical system may be deformed due to heat generated by the image sensor. More preferably, the equation (4) is set as follows.
| Ff / fcv | <1.3 (4a)

Furthermore, in the imaging apparatus of the present invention, when the distance in terms of air from the surface closest to the image side of the optical system 102 to the imaging element 103 is SK,
0.52 <SK / FB <1.10 (5)
It is characterized by satisfying. When the expression (5) is satisfied, the distance between the optical system 102 and the image sensor 103 can be increased, and a space for arranging the optical filter 106 between the optical system 102 and the image sensor 103 can be secured. By disposing the optical filter 106 between the optical system 102 and the image sensor 103, for example, a filter insertion / removal mechanism when switching the density of the ND filter is facilitated. On the contrary, when the optical filter is disposed on the object side of the optical system, a mount exists near the optical filter, so that it is difficult to secure a space for the filter insertion / removal mechanism. In addition, when an optical filter is arranged in the optical system and the insertion / removal of the filter is considered, it is necessary to divide the lens barrel of the optical system across the optical filter, and it becomes difficult to match the coaxiality of each lens barrel. If the upper limit of the equation (5) is not satisfied, the distance between the optical system and the image sensor becomes long, and it becomes difficult to reduce the size of the image pickup apparatus. If the lower limit of the expression (5) is not satisfied, the distance between the optical system and the image sensor becomes short, and it becomes difficult to secure a space for a mechanical structure for inserting and removing the optical filter. More preferably, the formula (5) is set as follows.
0.6 <SK / FB <1.0 (5a)

Furthermore, in the imaging apparatus of the present invention, when the optical system 102 is composed of six or less lenses, and the distance from the most object-side surface to the image-side surface of the optical system 102 is Lcv,
0.2 <Lcv / FB / β <0.6 (6)
It is characterized by satisfying. By satisfying the expression (6), both the downsizing of the imaging device and high optical performance are achieved. If the upper limit of the expression (6) is not satisfied, the thickness of the optical system 102 in the optical axis direction becomes larger than the lateral magnification of the optical system 102, so that it is difficult to reduce the size of the imaging apparatus. If the lower limit of the expression (6) is not satisfied, the thickness of the optical system 102 in the optical axis direction is small, which is advantageous for downsizing of the imaging device, but the refractive power of each lens constituting the optical system 102 becomes strong and high. It becomes difficult to achieve optical performance. More preferably, the formula (6) is set as follows.
0.24 <Lcv / FB / β <0.58 (6a)
More preferably, the formula (6) is set as follows.
0.24 <Lcv / FB / β <0.43 (6b)

Furthermore, the imaging apparatus according to the present invention includes the negative lens, the negative lens, the positive lens or the negative lens, the positive lens, and the negative lens in order from the object side to the image side, and the focal point of the lens closest to the object side. When the distance is f1,
0.05 <| f1 / fcv | <0.60 (7)
It is characterized by satisfying. By setting the most object side lens of the optical system 102 as a negative lens, the rear principal point of the optical system 102 can be set on the object side, so that the image points of the optical system 102 and the optical system 102 can be separated. . For this reason, the configuration is advantageous for securing the distance between the optical system 102 and the image sensor 103. In addition, by configuring the second and third lenses from the object side of the optical system 102 with a negative lens and a positive lens, it is possible to correct spherical aberration and chromatic aberration generated by the most negative lens on the object side. Furthermore, satisfying the expression (7) achieves both the securing of the distance between the optical system 102 and the image sensor 103 and high optical performance. If the upper limit of the expression (7) is not satisfied, the refractive power of the lens closest to the object side of the optical system becomes smaller than the refractive power of the optical system, so that it is difficult to ensure the distance between the optical system 102 and the image sensor 103. Become. If the lower limit of the expression (7) is not satisfied, the refractive power of the lens closest to the object side of the optical system becomes large and the curvature becomes strong, making it difficult to achieve high optical performance. More preferably, the formula (7) is set as follows.
0.07 <| f1 / fcv | <0.52 (7a)

Furthermore, in the imaging apparatus of the present invention, when the first lens group is a lens from the most object side lens of the optical system 102 to the third lens from the object side, the average refractive index of the negative lens constituting the first lens group is obtained. nav, when the average Abbe number of the negative lens is νn and the Abbe number of the positive lens is νp,
1.8 <nav (8)
5 <νn−νp <20 (9)
It is characterized by satisfying. The Abbe number ν is NF as the refractive index at the F line, Nd as the refractive index at the d line, and NC as the refractive index at the C line.
v = (Nd-1) / (NF-NC)
Defined by By satisfying the expressions (8) and (9), high optical performance is achieved. Expression (8) defines the refractive index of the negative lens constituting the first lens group. By using a high refractive index material for the negative lens having a strong refractive power, the curvature of the negative lens becomes loose and spherical aberration is obtained. It becomes easy to correct. As a further effect, correction of Petzval sum is advantageous, and correction of curvature of field at the periphery of the screen is possible. Equation (9) defines the difference between the average Abbe number of the negative lens constituting the first lens group and the Abbe number of the positive lens, and appropriately sets the refractive power of each lens constituting the first lens group. It becomes possible. If the lower limit of the expression (8) is not satisfied, the curvature of each lens constituting the first lens group becomes strong, and it becomes difficult to achieve high optical performance. If the upper limit of equation (9) is not satisfied, a material having a relatively large Abbe number is used for the negative lens, and it becomes difficult to select a material with a high refractive index for the negative lens. If the lower limit of the expression (9) is not satisfied, the difference between the Abbe numbers of the positive lens and the negative lens in the first lens group becomes small and the curvature of each lens becomes strong. As a result, it becomes difficult to achieve high optical performance. .
More preferably, equations (8) and (9) should be set as follows.
1.90 <nav <2.05 (8a)
7 <νn−νp <16 (9a)

  Hereinafter, a specific configuration of the imaging apparatus of the present invention will be described based on the characteristics of the optical system of Numerical Example 1 corresponding to Example 1. FIG.

  FIG. 2 is a lens cross-sectional view of the interchangeable lens as an example that is mounted on the imaging device of each embodiment of the present invention when focused at infinity at the wide angle end. FIG. 3 is a longitudinal aberration diagram when the interchangeable lens is focused at infinity at the wide-angle end. The value of the focal length is a value when a numerical example described later is expressed in mm. The same applies to the following numerical examples.

  In FIG. 2, a first lens unit (focus lens unit) U1 having a positive refractive power that moves in the order of focusing from the object side to the image side is provided. The zoom lens further includes a second lens unit (variator) U2 having a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end. Further, a third lens unit (compensator) U3 having a positive refractive power that moves in a non-linear manner on the optical axis in conjunction with the movement of the second lens unit U2 and corrects image plane fluctuations associated with zooming is provided. Yes. Further, the zoom lens has a fourth lens unit (relay lens unit) U4 having a positive refractive power that does not move for zooming and has an imaging function. The second lens unit U2 and the third lens unit U3 constitute a zooming system. SP is an aperture stop, which is disposed on the object side of the fourth lens unit U4. P is a color separation optical system or an optical filter, and is shown as a glass block. I is an imaging surface, which corresponds to the imaging surface of the solid-state imaging device.

  In the longitudinal aberration diagram, the straight line and the alternate long and short dash line in the spherical aberration are the e-line and the g-line, respectively. The dotted line and solid line in astigmatism are the meridional image surface and the sagittal image surface, respectively, and the alternate long and short dash line in the lateral chromatic aberration is the g line. ω is a half angle of view, and Fno is an F number. In the longitudinal aberration diagram, spherical aberration is drawn on a scale of 0.5 mm, astigmatism is 0.5 mm, distortion is 10%, and lateral chromatic aberration is drawn on a scale of 0.1 mm. In other examples described later, aberration diagrams are also described with the same scale. In Example 5 (FIG. 15), spherical aberration is 1.0 mm, astigmatism is 1.0 mm, distortion is 10%, and chromatic aberration of magnification. Is described on a scale of 0.2 mm. The flange surface of the mount of the interchangeable lens is disposed at a position 1.832 mm from the 55th surface to the object side, and the flange back is 48 mm in terms of air. The interchangeable lens is an interchangeable lens for 2/3 inch format, and the image circle IC is 11 mm.

FIG. 4 is a lens cross-sectional view in a state where an interchangeable lens is mounted on the imaging apparatus of the present embodiment. In FIG. 4, ML is an interchangeable lens, CV is an optical system built in the imaging apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 5 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide angle end in a state where the interchangeable lens is attached to the imaging apparatus of the present embodiment. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a biconcave lens G1, a cemented lens of a meniscus positive lens G2 concave on the image side and a meniscus negative lens G3 convex on the object side, and a biconvex lens G4. In the imaging apparatus of the present embodiment, an optical filter F is disposed between the optical system and the imaging surface. In this embodiment, the front group is G1, the rear group is G2 to G4, and the first lens group is G1 to G3. By using the imaging apparatus of the present embodiment as an imaging system in which an interchangeable lens is mounted, the image circle of the interchangeable lens is enlarged 1.3 times. In addition, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 14.3 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 6 is a lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 6, ML is an interchangeable lens, CV is an optical system built in the image pickup apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 7 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end in a state where the interchangeable lens is attached to the imaging apparatus of the present embodiment. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a cemented lens 1 composed of a meniscus negative lens G1 convex toward the object side, a meniscus negative lens G2 convex toward the object side, and a meniscus positive lens G3 concave toward the image side. . Further, it is composed of a cemented lens 2 composed of a meniscus negative lens G4 convex to the object side and a biconvex lens G5, and a cemented lens 3 composed of a biconcave lens G6 and a biconvex lens G7. In this embodiment, the front group is G1 to G3, the rear group is G4 to G7, and the first lens group is G1 to G3. By attaching an interchangeable lens to the imaging apparatus of the present embodiment, the image circle of the interchangeable lens is enlarged by 2.83 times. Further, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 31.1 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 8 is a lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 8, ML is an interchangeable lens, CV is an optical system built in the image pickup apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 9 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end with the interchangeable lens attached to the image pickup apparatus of the present embodiment. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a cemented lens of a meniscus negative lens G1 that is convex on the object side, a meniscus negative lens G2 that is convex on the object side, and a meniscus positive lens G3 that is concave on the image side, and a concave lens on the image side. It comprises a meniscus positive lens G4. In this embodiment, the front group is G1 to G3, the rear group is G4, and the first lens group is G1 to G3. By attaching the interchangeable lens to the image pickup apparatus of the present embodiment, the image circle of the interchangeable lens is enlarged by 1.35 times. Further, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 13.5 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 10 is a lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 10, ML is an interchangeable lens, CV is an optical system built in the imaging apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 11 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide angle end in a state where the interchangeable lens is mounted on the imaging apparatus of the present embodiment. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a meniscus negative lens G1 convex toward the object side, a cemented lens 1 composed of a biconcave lens G2 and a biconvex lens G3, and a cemented lens composed of a biconvex lens G4 and a meniscus negative lens G5 convex toward the image side. The lens 2 includes a positive meniscus lens G6 that is concave on the image side. In this embodiment, the front group is G1, the rear group is G2 to G6, and the first lens group is G1 to G3. By attaching the interchangeable lens to the image pickup apparatus of the present embodiment, the image circle of the interchangeable lens is enlarged by 1.5 times. Further, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 16.5 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 12 is a lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 12, ML is an interchangeable lens, CV is an optical system built in the imaging apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 13 is a longitudinal aberration diagram when the interchangeable lens is mounted on the imaging apparatus of the present embodiment and the interchangeable lens is focused at infinity at the wide angle end. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a meniscus negative lens G1 convex toward the object side, a cemented lens 1 of a meniscus negative lens G2 convex toward the object side, and a meniscus positive lens G3 concave toward the image side, and a biconcave lens G4. It consists of a cemented lens 2 with a biconvex lens G5. In this embodiment, the front group is G1 to G3, the rear group is G4 and G6, and the first lens group is G1 to G3. By attaching the interchangeable lens to the image pickup apparatus of the present embodiment, the image circle of the interchangeable lens is doubled. Further, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 22 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 14 is a lens cross-sectional view in a state where an interchangeable lens is mounted on the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 14, ML is an interchangeable lens, CV is an optical system built in the imaging apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 15 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end in a state where the interchangeable lens is attached to the imaging apparatus of the present embodiment. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes a meniscus negative lens G1 that is convex from the object side to the image side, a cemented lens 1 of a biconcave lens G2 and a biconvex lens G3, a biconvex lens G4, and a biconvex lens G5. In this embodiment, the front group is G1, the rear group is G2 to G5, and the first lens group is G1 to G3. By attaching the interchangeable lens to the image pickup apparatus of the present embodiment, the image circle of the interchangeable lens is enlarged by 1.4 times. Further, the image pickup apparatus of the present embodiment has an image pickup element having a diagonal length of 15.4 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

FIG. 16 is a lens cross-sectional view in a state where an interchangeable lens is attached to the imaging apparatus of the present embodiment. The basic configuration of the imaging apparatus is the same as that of the first embodiment. In FIG. 16, ML is an interchangeable lens, CV is an optical system built in the imaging apparatus , and F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an image pickup surface, which corresponds to the image pickup surface of the solid-state image sensor. FIG. 17 is a longitudinal aberration diagram when the interchangeable lens is mounted on the imaging apparatus of the present embodiment and the interchangeable lens is focused at infinity at the wide angle end. The optical system of the present example is disposed at a position 12 mm from the 55th surface, which is the surface closest to the image side of the interchangeable lens, to the image side.

  Next, the optical system in the present embodiment will be described. The optical system includes, in order from the object side to the image side, a meniscus negative lens G1 that is convex on the object side, a cemented lens 1 of a meniscus negative lens G2 that is convex on the object side and a biconvex lens G3, and a meniscus negative lens G4 that is convex on the image side. It is composed of a cemented lens 2 with a concave meniscus positive lens G5 on the object side and a concave meniscus positive lens G6 on the image side. In this embodiment, the front group is G1 to G3, the rear group is G4 to G6, and the first lens group is G1 to G3. By attaching the interchangeable lens to the image pickup apparatus of the present embodiment, the image circle of the interchangeable lens is enlarged by 1.44 times. Further, the imaging apparatus of the present embodiment has an imaging element having a diagonal length of 15.84 mm.

  Table 1 shows values corresponding to the conditional expressions of this example. The present embodiment satisfies the conditional expressions (1) to (9), has a function of making the focal length of the interchangeable lens longer, and achieves downsizing of the photographing system.

The imaging apparatus illustrated in FIG. 18 includes a movable mechanism 109 that can move the optical system 102 in the optical axis direction. Deviation occurs in the image forming position of the optical system 102 due to manufacturing errors such as a gap between the lenses constituting the optical system 102, a thickness error, and a curvature error. An optical system 102 and the imaging device 103 when no write set to the image pickup apparatus 101, by moving the optical system 102 in the optical axis direction, and can be imaged the imaging position of the optical system 102 to the image sensor 103 Become.

The imaging apparatus illustrated in FIG. 19 includes a movable mechanism 110 that can move the imaging element 103 in the optical axis direction. Deviation occurs in the image forming position of the optical system 102 due to manufacturing errors such as a gap between the lenses constituting the optical system 102, a thickness error, and a curvature error. An optical system 102 and the imaging device 103 when no write set to the image pickup device 101, an image pickup device 103 is moved in the optical axis direction, and can be imaged the imaging position of the optical system 102 to the image sensor 103 Become.

  Numerical examples corresponding to the embodiments of the present invention will be shown below. In each numerical example, i indicates the order of the surfaces from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th and i + 1-th interval from the object side, ndi , Νdi are the refractive index and Abbe number of the optical member between the i-th surface and the (i + 1) -th surface. BF is an air equivalent back focus. The last three surfaces are glass blocks such as filters.

The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the cone constant, and A4, A6, A8, and A10 are non- The spherical coefficient is expressed by the following equation. “E-Z” means “× 10 ^−Z ”.

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

<Interchangeable lens>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
1 * 17634.271 4.70 1.69680 55.5 183.19
2 109.899 46.92 152.38
3 -201.325 4.50 1.69680 55.5 151.93
4 1829.577 0.15 155.00
5 283.523 12.64 1.80518 25.4 158.03
6 2167.464 5.15 157.76
7 -2805.896 18.49 1.48749 70.2 157.47
8 -196.467 0.20 157.29
9 -1000.469 4.40 1.80518 25.4 149.49
10 603.998 16.55 1.48749 70.2 146.78
11 -307.782 32.56 146.03
12 315.156 17.48 1.48749 70.2 155.94
13 -596.320 0.15 156.09
14 191.137 4.40 1.80518 25.4 155.18
15 118.065 0.39 149.21
16 119.291 35.44 1.48749 70.2 149.24
17 -534.941 0.15 148.58
18 * 200.940 12.13 1.62041 60.3 141.59
19 826.607 (variable) 140.30
20 129.425 1.50 1.88300 40.8 52.29
21 64.705 6.90 48.69
22 -200.592 1.50 1.72916 54.7 47.84
23 41.776 10.46 1.84666 23.8 43.43
24 -106.134 1.50 1.72916 54.7 42.53
25 86.715 6.25 41.00
26 -81.264 1.50 1.88300 40.8 40.91
27 227.627 (variable) 41.93
28 600.754 6.75 1.62041 60.3 51.99
29 -114.148 0.15 52.85
30 117.668 11.71 1.48749 70.2 53.85
31 -75.558 0.09 53.66
32 -76.874 1.60 1.80518 25.4 53.57
33 -134.820 0.15 53.89
34 86.226 1.60 1.80518 25.4 52.65
35 48.805 10.30 1.48749 70.2 50.88
36 2324.271 0.15 50.18
37 94.553 6.65 1.62041 60.3 49.18
38 -6865.358 (variable) 47.86
39 (Aperture) ∞ 3.42 29.98
40 -46.195 1.50 1.77250 49.6 29.29
41 36.572 7.11 1.78472 25.7 28.98
42 -43.549 1.50 1.77250 49.6 28.89
43 69.864 5.93 28.57
44 -41.024 19.74 1.77250 49.6 28.98
45 -41.228 8.40 37.08
46 -195.562 4.78 1.62041 60.3 37.58
47 -59.391 0.20 37.84
48 277.984 1.80 1.88300 40.8 36.81
49 37.998 7.73 1.48749 70.2 35.68
50 -82.491 0.20 35.71
51 81.354 8.17 1.48749 70.2 34.96
52 -31.106 1.80 1.83400 37.2 34.70
53 -201.103 0.20 35.02
54 180.091 6.65 1.48749 70.2 34.93
55 -40.373 5.00 34.74
56 ∞ 33.00 1.60859 46.4 40.00
57 ∞ 13.20 1.51633 64.2 40.00
58 ∞ 12.00 40.00
Image plane ∞

Aspheric data 1st surface
K = 1.68492e + 004 A 4 = 2.64785e-008 A 6 = -1.47610e-012 A 8 = 8.96960e-017 A10 = -3.30657e-021

18th page
K = -1.44619e-001 A 4 = -7.46282e-009 A 6 = -2.04300e-013 A 8 = 1.70939e-017 A10 = -3.75331e-021

Various data

Focal length 6.70
F number 1.50
Half angle of view 39.38
Statue height 5.50
Total lens length 606.22
BF 12.00

d19 3.93
d27 173.49
d38 1.30

Entrance pupil position 107.96
Exit pupil position 328.64
Front principal point position 114.80
Rear principal point position 5.30

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 120.59 216.39 131.11 72.76
2 20 -30.00 29.61 13.82 -6.54
3 28 50.00 39.16 11.50 -15.21
4 39 40.05 130.33 45.82 10.33

<Numerical Example 1>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 -157.317 1.10 2.00100 29.1 29.36
57 38.170 3.50 28.62
58 43.949 4.48 1.80809 22.8 30.45
59 377.668 1.10 1.88300 40.8 30.32
60 87.306 0.20 30.19
61 62.000 5.06 1.58144 40.8 30.34
62 -68.247 10.00 30.25
63 ∞ 2.00 1.51633 64.1 40.00
64 ∞ 28.83 40.00
Image plane ∞

Various data

Focal length 8.71
F number 1.95
Half angle of view 39.38
Statue height 7.15
BF 28.83

<Numerical Example 2>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 148.228 1.20 2.00100 29.1 28.69
57 30.603 11.76 27.34
58 77.609 1.10 1.88300 40.8 30.03
59 22.099 7.65 1.80809 22.8 29.78
60 762.559 33.61 29.83
61 135.306 1.20 1.95375 32.3 32.40
62 31.326 15.07 1.53172 48.8 32.03
63 -28.937 0.20 33.31
64 -70.515 1.20 2.00100 29.1 31.80
65 69.867 4.31 1.85478 24.8 31.98
66 -169.728 10.00 32.10
67 ∞ 2.00 1.51633 64.1 40.00
68 ∞ 28.70 40.00
Image plane ∞

Various data

Focal length 18.94
F number 4.24
Half angle of view 39.38
Statue height 15.55
BF 28.70

<Numerical Example 3>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 472.643 1.10 1.88300 40.8 28.93
57 62.360 5.00 28.17
58 33.563 1.10 1.88300 40.8 27.08
59 26.045 2.14 1.80518 25.4 26.20
60 31.109 9.34 25.57
61 56.850 2.40 1.60342 38.0 24.46
62 173.352 10.00 24.08
63 ∞ 2.00 1.51633 64.1 40.00
64 ∞ 17.98 40.00
Image plane ∞

Various data

Focal length 9.05
F number 2.02
Half angle of view 36.73
Statue height 6.75
BF 17.98

<Numerical Example 4>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 146.968 1.00 2.04976 27.1 28.50
57 34.550 4.57 27.38
58 -62.037 1.00 1.95375 32.3 27.42
59 38.828 5.48 1.92286 18.9 29.07
60 -104.388 2.63 29.59
61 71.901 5.85 1.51742 52.4 31.56
62 -49.878 1.00 1.84666 23.8 31.68
63 -113.287 0.20 32.12
64 41.365 4.79 1.51823 58.9 32.55
65 2879.165 10.00 32.21
66 ∞ 2.00 1.51633 64.1 40.00
67 ∞ 34.48 40.00
Image plane ∞

Various data

Focal length 10.05
F number 2.25
Half angle of view 39.38
Statue height 8.25
Total lens length 628.02
BF 34.48

<Numerical example 5>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 162.179 1.20 2.00100 29.1 28.70
57 33.030 10.69 27.44
58 40.334 1.10 1.95375 32.3 29.54
59 18.712 7.51 1.80809 22.8 28.21
60 247.670 14.85 28.00
61 -38.115 1.20 1.95375 32.3 26.08
62 204.648 7.12 1.51742 52.4 27.17
63 -23.400 10.00 27.97
64 ∞ 2.00 1.51633 64.1 40.00
65 ∞ 25.56 40.00
Image plane ∞

Various data

Focal length 13.40
F number 3.00
Half angle of view 39.38
Statue height 11.00
Total lens length 636.24
BF 25.56

<Numerical Example 6>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 400.455 1.00 2.04976 27.1 27.65
57 37.612 4.12 26.81
58 -63.364 1.00 1.95375 32.3 26.86
59 48.077 4.76 1.92286 18.9 28.47
60 -104.208 0.20 29.05
61 74.800 5.89 1.49700 81.5 30.28
62 -106.671 0.20 30.75
63 38.750 8.04 1.48749 70.2 31.09
64 625.170 10.00 29.93
65 ∞ 2.00 1.51633 64.1 40.00
66 ∞ 29.99 40.00
Image plane ∞

Various data

Focal length 9.38
F number 2.10
Half angle of view 39.38
Statue height 7.70
Total lens length 622.22
BF 29.99

<Numerical Example 7>
Unit mm

Surface data surface number ri di ndi vdi Effective diameter
56 199.269 1.00 2.04976 27.1 27.87
57 36.284 2.97 26.91
58 534.236 1.00 1.95375 32.3 27.02
59 24.998 6.28 1.89286 20.4 27.41
60 -151.995 3.50 27.61
61 -29.943 1.00 1.72825 28.5 27.66
62 -154.031 5.25 1.48749 70.2 29.37
63 -27.477 1.38 30.12
64 32.253 6.62 1.51823 58.9 31.69
65 231.036 10.00 30.87
66 ∞ 2.00 1.51633 64.1 40.00
67 ∞ 29.99 40.00
Image plane ∞

Various data

Focal length 9.65
F number 2.16
Half angle of view 39.38
Statue height 7.92
Total lens length 626.03
BF 29.99

DESCRIPTION OF SYMBOLS 101 Image pick-up apparatus 102 Optical system 103 Image pick-up element 104 Mount 105 Object of optical system

Claims (13)

And mounting you mount the interchangeable lens, an image pickup apparatus having an optical system, an image sensor, a,
Has an optical filter between said optical system and the imaging element,
The optical system has a refractive power, and an object point located on the image side from the most object-side surface of the optical system is imaged on the image sensor ,
The optical system has a negative lens, a negative lens, and a positive lens in order from the object side to the image side, or has a negative lens, a positive lens, and a negative lens in order from the object side to the image side. And
The first lens group is the lens from the most object side of the optical system to the third lens from the object side of the optical system, and the average refractive index of the negative lens constituting the first lens group is nav. An average Abbe number of a negative lens constituting one lens group is denoted by νn, and an Abbe number of a positive lens constituting the first lens group is denoted by νp.
1.8 <nav
5 <νn−νp <20
An imaging apparatus characterized by satisfying the following conditional expression: Wherein the optical system, an imaging apparatus according to claim 1, characterized in Tei Rukoto disposed on the image side of the mount. The lateral magnification of the previous SL optics and beta, the image circle of the interchangeable lens and the IC, and the diagonal length of the image pickup device as an I,
0.8 <IC × β / I <1.3
Or claim 1 and satisfies a conditional expression imaging device according to claim 2. The distance along the optical axis between the flange surface or found the object point of the mounting and FB, the distance on the optical axis from the flange surface of the mount to the image sensor is L, the lateral magnification of the previous SL optical system β as a,
1.0 <L / FB <3.0
1.0 <β <3.0
The imaging apparatus according to any one of claims 1 to 3 and satisfies the following conditional expression. The imaging apparatus according to any one of claims 1 to 4, wherein the distance on the optical axis is variable between the optical system and the imaging element. The imaging apparatus according to claim 5, wherein the optical system is movable on an optical axis. The imaging apparatus according to claim 5, wherein the imaging element is movable on an optical axis. At a maximum air gap in the optical system, the object-side portion of the optical system and the front group, as a group the rear portions other than the front group of the optical system, wherein the front group includes a negative the imaging apparatus according to any one of claims 1 to 7, characterized in that it has a refractive power. The focal length of the front group and ff, and the focal length of the optical system and fcv,
| Ff / fcv | <1.5
The image pickup apparatus according to claim 8, wherein the following conditional expression is satisfied. Wherein the distance on the optical axis from the flange surface of the mount to the object point and FB, and a and SK distance equivalent air from a surface on the most image side of the optical system to the imaging device,
0.52 <SK / FB <1.10
The imaging apparatus according to any one of claims 1 to 9, characterized by satisfying the following conditional expression. The optical system is composed of seven or less lenses, and the distance on the optical axis from the flange surface of the mount to the object point is FB, and the most image of the optical system from the most object side surface of the optical system. the distance to the surface on the side and Lcv, the lateral magnification of the previous SL optical system as a beta,
0.2 <Lcv / FB / β <0.6
The imaging apparatus according to any one of claims 1 to 10, characterized in that satisfies the following conditional expression. Wherein the focal length of the optical system and fcv, the focal length of the negative lens on the most object side of the optical system as a f1,
0.05 <| f1 / fcv | <0.60
The imaging apparatus according to any one of claims 1 to 11, characterized in that satisfies the following conditional expression. An imaging device according to any one of claims 1 to 12 ,
A mounted interchangeable lens mount of the imaging device,
An imaging system comprising:

Images