JP2015138050A - Amphibian variable magnification lens, imaging device and manufacturing method of amphibian variable magnification lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amphibian variable magnification lens, imaging device and manufacturing method of the amphibian variable magnification lens that allow for varying magnification and are excellent in optical performance in both of a land photographing state and underwater photographing state even with a simple configuration.SOLUTION: An amphibian variable magnification lens 10 able to photograph in an underwater and land comprises, arranged in order from an object side along an optical axis,: a first lens group G1 having a lens shaped to have a lens surface on the most object side with a convex surface directed to the object side; and at least three moving lens groups (a second lens group G2, third lens group G, fourth lens group and fifth lens group in Fig.1). Upon varying magnification from a wide-angle end state to a telephoto end state, the first lens group G1 is stationary, and the moving lens groups move in a mutually independent manner. Of the moving lens groups, at least two lens groups (the fourth lens group G4 and fifth lens group G5 in Fig.1) are different in a movement trajectory upon zooming in a land photographing state and underwater photographing state.

Description

  The present invention relates to an amphibious variable-power lens device, an imaging device, and an amphibious variable-power lens device manufacturing method.

  Conventionally, amphibious variable power lenses have been proposed (see, for example, Patent Documents 1 and 2).

JP-A-7-159687 Japanese Patent Laid-Open No. 7-159589

  However, the conventional amphibious zoom lens is not convenient because zooming cannot be performed or an auxiliary lens system needs to be mounted in an underwater shooting state.

  The present invention has been made in view of such problems, and has a simple configuration, but can be changed in both land and underwater shooting conditions, and can be used for amphibious use having excellent optical performance. It is an object of the present invention to provide a method of manufacturing a double lens device, an imaging device, and an amphibious variable power lens device.

  In order to achieve such an object, an amphibious zoom lens device according to the present invention is an amphibious zoom lens device capable of photographing underwater and on land, and is arranged in order from the object side along the optical axis. However, it has a first lens group having a lens whose lens surface closest to the object side has a convex surface facing the object side, and at least three moving lens groups, and zooming from the wide-angle end state to the telephoto end state. At this time, the first lens group is fixed, the moving lens groups move independently from each other, and at least two of the moving lens groups are at the time of zooming in a land shooting state and an underwater shooting state. The movement trajectory is different.

  The amphibious variable power lens apparatus according to the present invention preferably satisfies the following conditional expression.

0.80 <R1 / Enpw <4.00
However,
R1: radius of curvature of the lens surface closest to the object side of the first lens group,
Enpw: Distance on the optical axis from the most object-side lens surface of the first lens group to the entrance pupil position in the infinity photographing state at the wide-angle end state in the land photographing state of the amphibious variable magnification lens apparatus.

  The amphibious variable power lens apparatus according to the present invention preferably satisfies the following conditional expression.

−0.90 <Δ1U / Δ1A <0.90
0.20 <Δ2U / Δ2A <2.00
However,
Δ1U: Of the at least two moving lens groups, the lens group located closest to the image side is required to change from the infinity shooting state at the wide-angle end state in the underwater shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ1A: Of the at least two moving lens groups, the lens group located closest to the image side needs to change from the infinity shooting state at the wide-angle end state in the land shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ2U: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the underwater shooting state to the infinity shooting state in the telephoto end state. The amount of movement required for the change (however, the amount of movement in the image plane direction is given a positive sign and the amount of movement in the object direction is attached with a negative sign),
Δ2A: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the land shooting state to the infinity shooting state in the telephoto end state. The amount of movement required to change the distance (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is assigned a negative sign).

  An amphibious variable magnification lens apparatus according to the present invention includes an identification unit that distinguishes between a land shooting state and an underwater shooting state, an operation unit for changing a focal length, and the focal length changed by the operation unit. A moving mechanism for moving at least one moving lens group among the moving lens groups along the optical axis in conjunction with the operation of the operating unit, and the moving lens group. , At least two moving lens groups that move at least two moving lens groups along the optical axis, respectively, other than the lens group that moves through the moving mechanism, and at least two moving mechanisms that move through the driving mechanism. In each of the land photographing state and the underwater photographing state of the moving lens group, a storage unit that stores a position on the optical axis set for each focal length, the identification unit, and the focal length detection unit Based on the output, the at a predetermined position stored in the storage unit such that at least two movable lens groups are moved, it is preferable that a control unit for controlling the driving of said at least two drive mechanisms.

  An amphibious variable magnification lens apparatus according to the present invention includes an identification unit that distinguishes between a land shooting state and an underwater shooting state, an operation unit for changing a focal length, and the focal length changed by the operation unit. And at least three independent driving mechanisms for moving at least three of the moving lens groups along the optical axis, respectively, and at least moving through the driving mechanism. In each of the three moving lens groups in the land shooting state and the underwater shooting state, the storage unit stores the position on the optical axis set for each focal length, and outputs from the identification unit and the focal length detection unit And a control unit that controls driving of the at least three driving mechanisms so that the at least three moving lens groups move to the predetermined positions stored in the storage unit. Door is preferable.

  The amphibious variable power lens apparatus according to the present invention includes 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 negative lens arrayed in order from the object side. The at least one moving lens group having a fourth lens group having a refractive power and a fifth lens group having a positive refractive power and moving via the moving mechanism includes the second lens group, and It is preferable that the at least two moving lens groups that move via two drive mechanisms include the fourth lens group and the fifth lens group.

  The amphibious variable power lens apparatus according to the present invention includes 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 negative lens arrayed in order from the object side. The at least three moving lens groups having a fourth lens group having a refractive power and a fifth lens group having a positive refractive power and moving via the at least three driving mechanisms are the second lens group, It is preferable that the fourth lens group and the fifth lens group are included.

  The amphibious variable power lens apparatus according to the present invention preferably has a meniscus lens having a convex surface on the object side closest to the object side, and satisfies the following conditional expression.

−0.15 <φ1 / φw <0.15
However,
φ1: refractive power of the meniscus lens in air
φw: Refracting power of the amphibious variable power lens apparatus in the wide-angle end state in the land photographing state.

  The amphibious variable power lens apparatus according to the present invention preferably has a meniscus lens having a convex surface on the object side closest to the object side, and satisfies the following conditional expression.

0.30 <R2 / TL <0.90
However,
R2: radius of curvature of the image side surface of the meniscus lens,
TL: Distance on the optical axis from the lens surface closest to the object side to the imaging surface of the amphibious variable magnification lens apparatus.

  An imaging apparatus according to the present invention includes any one of the above amphibious variable power lens apparatuses.

  The manufacturing method of an amphibious zoom lens apparatus according to the present invention is a manufacturing method of an amphibious zoom lens apparatus capable of photographing underwater and on land, and is arranged in order from the object side along the optical axis. A first lens group having a lens whose lens surface on the object side has a convex surface facing the object side, and at least three moving lens groups, and for zooming from the wide-angle end state to the telephoto end state, The first lens group is fixed, the moving lens groups move independently of each other, and at least two of the moving lens groups move during the zooming in a land shooting state and an underwater shooting state. Each lens is arranged in the housing so that the two are different.

  According to the present invention, an amphibious variable power lens apparatus, an imaging apparatus, and an amphibious variable lens that have a simple configuration and can perform zooming both in a land shooting state and an underwater shooting state, and have excellent optical performance. A method of manufacturing a double lens device can be provided.

It is a section lineblock diagram of the amphibious variable magnification lens device concerning a 1st embodiment. It is a figure which shows the transmission relationship of the information and control of the amphibious variable magnification lens apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the lens structure of the amphibious variable magnification lens apparatus which concerns on 1st Embodiment, and the figure which shows the movement locus | trajectory of each group from a wide-angle end state to a telephoto end state. FIG. 6 is a diagram illustrating various aberrations with respect to d-line (wavelength: 587.6 nm) in an infinitely focused state in an on-land photographing state of the amphibious variable magnification lens device according to the first embodiment, where (a) is a wide-angle end state, and (b) Intermediate focal length state, (c) shows the telephoto end state. FIG. 4 is a diagram illustrating various aberrations with respect to d-line (wavelength: 587.6 nm) in an infinite focus state in an underwater photographing state of the amphibious variable magnification lens device according to the first embodiment, (a) is a wide-angle end state, and (b) is a wide-angle end state. Intermediate focal length state, (c) shows the telephoto end state. It is a figure which shows the modification of the amphibious variable magnification lens apparatus which concerns on 1st Embodiment. It is a section lineblock diagram of the amphibious variable magnification lens device concerning a 2nd embodiment. It is a figure which shows the transmission relationship of the information and control of the amphibious variable magnification lens apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the lens structure of the amphibious variable magnification lens apparatus which concerns on 2nd Embodiment, and the figure which shows the movement locus | trajectory of each group from a wide-angle end state to a telephoto end state. FIG. 9 is a diagram illustrating various aberrations with respect to d-line (wavelength: 587.6 nm) in an infinitely focused state in an on-land photographing state of the amphibious variable magnification lens device according to the second embodiment, (a) is a wide-angle end state, and (b) is a wide-angle end state. Intermediate focal length state, (c) shows the telephoto end state. FIG. 9 is a diagram illustrating various aberrations with respect to d-line (wavelength: 587.6 nm) in an infinite focus state in an underwater photographing state of the amphibious variable magnification lens device according to the second embodiment, where (a) is a wide-angle end state, and (b) is a wide-angle state. Intermediate focal length state, (c) shows the telephoto end state. It is a figure which shows the modification of the amphibious variable magnification lens apparatus which concerns on 2nd Embodiment. It is a figure which shows the structure of a camera (imaging device) provided with the amphibious variable magnification lens apparatus which concerns on this embodiment. It is a flowchart which shows the manufacturing method of the amphibious variable magnification lens apparatus which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the characteristic configuration of the optical system common to each embodiment according to the present invention will be described. Next, a first embodiment according to the present invention will be described with reference to FIGS. A second embodiment according to the present invention will be described with reference to FIGS. The imaging apparatus according to these embodiments will be described with reference to FIG. The manufacturing method according to these embodiments will be described with reference to FIG.

  A characteristic configuration of the optical system ZL common to the amphibious variable power lens apparatus 10 according to the first embodiment and the amphibious variable power lens apparatus 100 according to the second embodiment will be described (see FIGS. 3 and 9). ).

  The amphibious variable power lens apparatus 10, 100 includes at least three movements, a first lens group G1 having lenses arranged in order from the object side and having the lens surface closest to the object side with a convex surface facing the object side. Lens group (for example, the second lens group G2, the fourth lens group G4, the fifth lens group G5), and the first lens group G1 is fixed at the time of zooming from the wide-angle end state to the telephoto end state, The moving lens groups move along the optical axis independently of each other, and at least two lens groups (for example, the fourth lens group G4 and the fifth lens group G5) of the moving lens groups are in a land photography state. An optical system ZL having a characteristic configuration in which the movement locus at the time of zooming differs in the underwater shooting state is mounted. In FIGS. 3 and 9, the movement locus of the fourth lens group G4 and the fifth lens group G5 in the land photographing state is indicated by a solid line, and the movement locus in the underwater photographing state is indicated by a dotted line.

  By fixing the first lens group G1, airtightness in an underwater shooting state is secured. Further, the zooming action is carried out by at least three moving lens groups. In particular, in this apparatus, the main lens zooming is performed by moving the second lens group G2, and the fourth lens group G4 and the fifth lens are moved. By moving the group G5, various aberrations such as field curvature associated with zooming and switching between a land photographing state and an underwater photographing state are corrected. Further, by making the lens surface (first surface m1) closest to the object side of the optical system ZL with a convex surface facing the object side, the change in the angle of view when placed in water is suppressed, and distortion and lateral chromatic aberration are suppressed. Is suppressed.

  As a result, the amphibious variable power lens apparatus 10 and 100 described later can be zoomed in both the land photographing state and the underwater photographing state while having a simple configuration, thereby achieving good optical performance. it can.

  In each embodiment, it is preferable that the optical system ZL satisfies the following conditional expression (1).

0.80 <R1 / Enpw <4.00 (1)
However,
R1: radius of curvature of the lens surface closest to the object side of the first lens group G1,
Enpw: the distance on the optical axis from the most object-side lens surface of the first lens group G1 to the entrance pupil position in the infinity photographing state at the wide-angle end state of the optical system ZL in the land photographing state.

  Conditional expression (1) is a condition for suppressing the occurrence of field curvature and distortion during underwater photography. If the lower limit value of conditional expression (1) is not reached, the power of the lens surface closest to the object side of the first lens group G1 changes greatly between the land photographing state and the underwater photographing state, and thereby the field curvature in the underwater photographing state. When the moving lens group is moved along a movement locus different from that in the land photographing state, the correction of the field curvature cannot be corrected. If the upper limit of conditional expression (1) is exceeded, it becomes close to the case where the lens surface closest to the object side of the first lens group G1 is configured as a plane, and is located closest to the object side of the first lens group G1 in the underwater shooting state. Positive distortion generated in the lens increases and cannot be corrected.

  In order to ensure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to 1.00. In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to 3.50.

  In each embodiment, it is preferable that the optical system ZL satisfies the following conditional expressions (2) and (3).

−0.90 <Δ1U / Δ1A <0.90 (2)
0.20 <Δ2U / Δ2A <2.00 (3)
However,
Δ1U: Of the at least two moving lens groups, the lens group located closest to the image side is required to change from the infinity shooting state at the wide-angle end state in the underwater shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ1A: Of the at least two moving lens groups, the lens group located closest to the image side needs to change from the infinity shooting state at the wide-angle end state in the land shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ2U: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the underwater shooting state to the infinity shooting state in the telephoto end state. The amount of movement required for the change (however, the amount of movement in the image plane direction is given a positive sign and the amount of movement in the object direction is attached with a negative sign),
Δ2A: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the land shooting state to the infinity shooting state in the telephoto end state. The amount of movement required to change the distance (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is assigned a negative sign).

  Conditional expressions (2) and (3) are conditions for favorably correcting various aberrations in each of the land photographing state and the underwater photographing state. When the upper limit value or lower limit value of conditional expression (2) is exceeded, correction of various aberrations including field curvature in the wide-angle end state and / or the telephoto end state in the land shooting state or underwater shooting state It becomes difficult. Similarly, when the upper limit value or lower limit value of conditional expression (3) is exceeded, various curvatures including field curvature are observed in either the wide-angle end state, the telephoto end state, or both in the land shooting state or the underwater shooting state. It becomes difficult to correct aberrations.

  In each embodiment, it is preferable that the optical system ZL has a meniscus lens L11 having a convex surface on the object side closest to the object side, and satisfies the following conditional expression (4).

−0.15 <φ1 / φw <0.15 (4)
However,
φ1: refracting power of the meniscus lens L11 in air,
φw: Refracting power of the optical system ZL in the wide-angle end state in the land photographing state.

  Conditional expression (4) is a condition for reducing the size of the optical system ZL, and thus the amphibious variable power lens apparatus 10 and 100 on which the optical system ZL is mounted. When the lower limit of conditional expression (4) is not reached, the refractive power of the meniscus lens L11 located closest to the object side becomes negatively larger, and the diameter of the lens located closer to the image side becomes larger than the meniscus lens L11. Therefore, it is not preferable. Exceeding the upper limit value of conditional expression (4) is not preferable because the refractive power of the meniscus lens L11 located closest to the object side increases positively and the diameter of the meniscus lens L11 increases.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to −0.10. In order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 0.10.

  In each embodiment, it is preferable that the optical system ZL has a meniscus lens L11 having a convex surface on the object side closest to the object side, and satisfies the following conditional expression (5).

0.30 <R2 / TL <0.90 (5)
However,
R2: radius of curvature of the image side surface of the meniscus lens L11,
TL: distance on the optical axis from the lens surface closest to the object side of the optical system ZL to the imaging surface.

  Conditional expression (5) is a condition for improving the aberration correction during underwater shooting. If the lower limit value of conditional expression (5) is not reached, the curvature of field generated on the image side surface of the meniscus lens L11 becomes large in the underwater shooting state and cannot be corrected. When the upper limit value of conditional expression (5) is exceeded, positive distortion occurring on the lens surface on the image side surface of the meniscus lens L11 becomes large and cannot be corrected.

  In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.34. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (5) to 0.80.

(First embodiment)
From here, the amphibious variable power lens apparatus 10 according to the first embodiment will be described. As shown in FIG. 1, the amphibious variable magnification lens apparatus 10 of the first embodiment includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, arranged in order from the object side, The optical system ZL (ZL1) includes a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power.

  The first lens group G1 is fixed on the optical axis via the first lens group fixing part 1a to the housing 1, and the third lens group G3 is fixed on the optical axis via the third lens group fixing part 1b. The second lens group G2 is located between the first lens group G1 and the third lens group G3. The fourth lens group G4 and the fifth lens group G5 are arranged on the image side of the third lens group G3. It is held by a member to be described later in the housing 1 so as to be independently movable along the direction.

  A mount member 2 is fixed to the image-side end portion 1c of the housing 1, and is fixed to an imaging device described later by the mount member 2.

  A pin 2b extending in the radial direction from the lens frame 2a holding the second lens group G2 is a cam groove 31a formed in an operating member 31 for changing the focal length through the long hole 3 opened in the housing 1. Is engaged. When the operation member 31 is rotated, the pin 2b moves along the cam groove 31a formed on the inner wall of the operation member 31, and thereby the second lens group G2 moves along the optical axis.

  The operation member 31 is connected to a focal length detection unit 32 disposed in the housing 1 via an interlocking member 32a. When the operation member 31 is operated, the focal length detection unit 32 detects a focal length change request via the interlocking member 32 a and outputs a focal length value corresponding to the rotation amount of the operation member 31.

  Note that a rubber ring (not shown) is sandwiched between the sliding portion between the operation member 31 and the housing 1 to prevent water from entering during underwater shooting.

  A switch member 37 for switching between the land photographing state and the underwater photographing state is provided outside the housing 1. A shooting state identification unit 33 for identifying the shooting state changed by the switch member 37 is disposed in the housing 1.

  The fourth lens group G4 is held by a fourth lens group lens frame 4a, and this lens frame 4a is disposed on a first support member 23 disposed between the third lens group fixing portion 1b and the image side end portion 1c. It is supported so as to be slidable, and is configured to move along the optical axis by the first drive mechanism 21 based on a control signal from the control unit 35 shown in FIG.

  The fifth lens group G5 is held by a fifth lens group lens frame 5a, and this lens frame 5a is attached to a second support member 24 disposed between the third lens group fixing portion 1b and the image side end portion 1c. It is supported so as to be slidable, and is configured to move along the optical axis by the second drive mechanism 22 based on a control signal from the control unit 35.

  The amphibious variable magnification lens apparatus 10 according to the first embodiment is a land photographing state of at least two moving lens groups that move via the drive mechanisms 21 and 22, that is, the fourth lens group G4 and the fifth lens group G5. In each of the underwater shooting states, position information on the optical axis set for each focal length is stored in the storage unit 34 shown in FIG. Note that the position information of the fourth lens group G4 and the fifth lens group G5 with the focal length not stored is set by the control unit 35 performing processing such as interpolation processing based on the stored position information. Can do.

  In the amphibious variable magnification lens apparatus 10 according to the first embodiment having such a configuration, as shown in FIG. 2, the photographing state identified by the photographing state identifying unit 33 by operating the switch member 37 is the control unit. 35. Further, the focal length detected by the focal length detection unit 32 by operating the operation member 31 is transmitted to the control unit 35.

  The control unit 35 reads position information on the optical axis of the fourth lens group G4 and the fifth lens group G5 corresponding to the transmitted shooting state and focal length from the storage unit 34, and passes through the first drive mechanism 21. The fourth lens group G4 and the fifth lens group G5 are independently moved to a predetermined optical axis position via the second drive mechanism 22.

  As a result, the amphibious variable magnification lens apparatus 10 according to the first embodiment changes the shooting state by operating the switch member 37, and changes the focal length by operating the operation member 31. By setting the positions of the fourth lens group G4 and the fifth lens group G5 on the optical axis at each focal length in the shooting state based on the position information stored in the storage unit 34, Various aberrations including curvature of field can be favorably corrected over the entire focal length range in both the land photographing state and the underwater photographing state.

  Next, the optical system ZL1 provided in the amphibious variable magnification lens apparatus 10 according to the first embodiment will be described with reference to FIGS. The characteristic configuration common to the second embodiment of the optical system ZL1 is as described above.

  3 are used independently for each embodiment in order to avoid complication of explanation due to an increase in the number of digits of the reference code. Therefore, even if the reference numerals common to the drawings according to the other embodiments are attached, they are not necessarily the same configuration as the other embodiments.

  As shown in FIG. 3, the optical system ZL1 provided in the amphibious variable magnification lens apparatus 10 according to the first embodiment includes a first lens group G1 having a positive refractive power and a first lens unit having a negative refractive power arranged in order from the object side. 2 lens group G2, 3rd lens group G3 of positive refractive power, 4th lens group G4 of negative refractive power, and 5th lens group G5 of positive refractive power.

  The first lens group G1 is composed of a meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a concave surface facing the image side, and a biconvex positive lens L13 arranged in order from the object side. It consists of a lens and a positive meniscus lens L14 having a convex surface facing the object side.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a concave surface facing the image side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens. It consists of a cemented lens with L24. The negative meniscus lens L21 includes an aspheric thin plastic resin layer on the object side surface.

  The third lens group G3 is arranged in order from the object side, a cemented lens of a negative meniscus lens L31 having a concave surface facing the image side and a biconvex positive lens L32, and a biconvex positive lens L33 and the object side. It consists of a cemented lens with a negative meniscus lens L34 having a concave surface, and a biconvex positive lens L35.

  The fourth lens group G4 includes a biconcave negative lens L41, and a cemented lens of a biconcave negative lens L42 and a biconvex positive lens L43, which are arranged in order from the object side.

  The fifth lens group G5 includes a biconvex positive lens L51, a cemented lens of a biconvex positive lens L52, and a negative meniscus lens L53 having a concave surface facing the object side, arranged in order from the object side, and the image side. And a negative meniscus lens L56 having a concave surface facing the object side, and a cemented lens of a negative meniscus lens L54 having a concave surface facing the lens and a biconvex positive lens L55. The image side surface of the biconvex positive lens L51 is aspheric.

  An iris diaphragm S is disposed adjacent to the image side of the third lens group G3.

  A filter group F is arranged between the fifth lens group G5 and the image plane I. The filter group F includes a low-pass filter for cutting a spatial frequency equal to or higher than the limit resolution of an image sensor such as a CCD or CMOS disposed on the image plane I, a cover glass of the image sensor, and the like.

  The image plane I is formed on an image sensor (not shown), and the image sensor is composed of a CCD, a CMOS, or the like.

  In the optical system ZL1 having the above-described configuration, the lens surface closest to the object side of the first lens group G1 has a radius of curvature that satisfies the above-described conditional expression (1), and has a convex surface facing the object side. As a result, the occurrence of distortion during underwater shooting is suppressed.

  The first lens group G1 and the third lens group G3 are always fixed.

  The second lens group G2 moves in the image plane direction during zooming from the wide-angle end state to the telephoto end state along the cam groove 31a in both the land photographing state and the underwater photographing state.

  The fourth lens group G4 has a land photographing state (solid arrow in FIG. 3) and an underwater photographing state (dotted arrow in FIG. 3) when zooming from the wide-angle end state to the telephoto end state by the first drive mechanism 21. ) And move to take different movement trajectories.

  The fifth lens group G5 has a land shooting state (solid arrow in FIG. 3) and an underwater shooting state (dotted arrow in FIG. 3) during zooming from the wide-angle end state to the telephoto end state by the second drive mechanism 22. ) And move to take different movement trajectories.

  Thus, by changing the movement trajectory of the fourth lens group G4 and the fifth lens group G5 between the land photographing state and the underwater photographing state, the imaging position is kept constant in the land photographing state and the underwater photographing state, It is possible to satisfactorily correct field curvature in both the land shooting state and the underwater shooting state.

  In focusing from the infinity shooting state to the close-up shooting state, the fourth lens group G4 is moved in the image plane direction. Also during focusing, the fourth lens group G4 is moved by the first drive mechanism 21 in the same manner as during zooming.

  Table 1 below lists specifications of the optical system ZL1 included in the amphibious variable magnification lens apparatus 10 according to the first embodiment. Surface numbers 1 to 41 in Table 1 correspond to the optical surfaces m1 to m41 shown in FIG.

  In [Lens data] in the table, the surface number is the order of the optical surfaces from the object side along the direction in which the light beam travels, R is the radius of curvature of each optical surface, and D is the next optical surface from each optical surface (or The distance between surfaces on the optical axis to the image plane), nd is the refractive index of the material of the optical member with respect to the d-line, and νd is the Abbe number with respect to the d-line of the material of the optical member. The object plane is the object plane, (variable) is the variable plane spacing, the curvature radius “∞” is the plane, (aperture S) is the iris diaphragm S, and the image plane is the image plane I. The refractive index of air “1.000000” is omitted. When the optical surface is an aspherical surface, the surface number is marked with *, and the column of curvature radius R indicates the paraxial curvature radius.

In [Aspherical data] in the table, the shape of the aspherical surface shown in [Lens data] is shown by the following equation (a). X (y) is the distance along the optical axis direction from the tangential plane at the apex of the aspheric surface to the position on the aspheric surface at height y, R is the radius of curvature of the reference sphere (paraxial radius of curvature), and κ is Ai represents the i-th aspherical coefficient. “E-n” indicates “× 10 ⁻ⁿ ”. For example, 1.234E-05 = 1.234 × 10 ⁻⁵ .

X (y) = (y ² / R) / {1+ (1−κ × y ² / R ² ) ^1/2 } + A 4 · y ⁴ + A 6 · y ⁶ + A 8 · y ⁸ + A 10 · y ¹⁰ + A 12 · y ¹² + A 14 Y ¹⁴ ... (a)

  In [Various data] in the table, f is the focal length of the entire lens system, FNO is the F number, 2ω is the angle of view (unit: °), Y is the image height, TL is the total lens length (the most lens on the optical axis) Bf represents back focus, the distance from the lens surface on the object side to the paraxial image plane). Di is a variable interval and indicates a variable interval between the i-th surface and the (i + 1) -th surface.

  In [Lens Group Data] in the table, the start surface number (the most object-side lens surface number), the end surface number (the most image-side lens surface number), and the focal length in the air are shown.

  The [Position data of each lens group] in the table is infinite at each focal length in the land shooting state and the underwater shooting state with reference to the position of each lens group in the infinity shooting state in the wide-angle end state in the land shooting state. The position of each lens group in the far shooting state is shown. The sign is positive in the image plane direction.

  “Values corresponding to conditional expressions” in the table indicate values corresponding to the conditional expressions (1) to (5).

  Hereinafter, in all the specification values, “mm” is generally used for the focal length f, curvature radius R, surface interval D, and other lengths, etc. unless otherwise specified. Since the same optical performance can be obtained even if proportional expansion or proportional reduction is performed, the present invention is not limited to this. Further, the unit is not limited to “mm”, and other appropriate units can be used.

  The description of the table so far is the same in other embodiments.

(Table 1)
[Lens data]
Surface number R D nd νd
1 60.0000 5.0000 1.516800 63.88
2 58.2950 15.8000
3 102.3091 2.0000 1.795040 28.69
4 41.8010 10.4000 1.497820 82.57
5 -1007.6756 0.1000
6 37.6062 5.1500 1.834810 42.73
7 98.9884 D7 (variable)
* 8 99.2450 0.1500 1.553890 38.09
9 94.6723 1.4000 1.834810 42.73
10 12.0783 6.0000
11 -32.7960 1.0000 1.834810 42.73
12 46.9143 0.4000
13 25.5606 3.8000 1.846660 23.78
14 -54.2180 1.0000 1.816000 46.59
15 54.1534 D15 (variable)
16 34.7874 0.8000 1.850260 32.35
17 16.6502 2.6000 1.618000 63.34
18 -37.1204 1.2000
19 48.7843 2.6000 1.497820 82.57
20 -18.5410 0.8000 1.850 260 32.35
21 -41.7038 0.3000
22 47.8525 1.6000 1.696800 55.52
23 -59.5425 0.5000
24 ∞ (Aperture) D24 (Variable)
25 -33.1327 0.8000 1.816000 46.59
26 23.8736 0.7000
27 -23.1424 0.8000 1.816000 46.59
28 16.9872 2.0000 1.808090 22.74
29 -33.9829 D29 (variable)
30 49.4602 3.5000 1.589130 61.18
* 31 -19.7954 0.1000
32 23.4122 4.4000 1.497820 82.57
33 -23.4006 1.0000 1.950000 29.37
34 -80.0819 0.3000
35 85.4967 1.0000 1.883000 40.66
36 14.9004 4.0000 1.517420 52.20
37 -50.2458 1.4500
38 -30.3940 1.0000 2.000690 25.46
39 -82.9601 D39 (variable)
40 ∞ 2.7900 1.516800 63.88
41 ∞ Bf
Image plane ∞

[Aspherical data]
8th surface κ = +15.1751
A4 = + 4.64891E-06
A6 = -1.26998E-08
A8 = -3.35661E-10
A10 = + 2.59761E-12
A12 = -8.51930E-15
A14 = + 1.02560E-17

31st plane κ = +1.2313
A4 = + 1.39795E-05
A6 = + 3.25121E-08
A8 = 0.00000E + 00
A10 = 0.00000E + 00
A12 = 0.00000E + 00
A14 = 0.00000E + 00

[Various data]
(Land shooting state)
f 10.60 19.05 45.07
FNO 4.58 4.99 5.48
2ω 76.48 44.65 19.40
Y 8.00 8.00 8.00
TL 158.41 158.41 158.41
D7 1.822 11.822 22.822
D15 30.318 20.318 9.318
D24 2.508 5.447 12.132
D29 17.391 15.008 11.482
D39 17.831 17.275 14.116
Bf 2.104 2.104 2.104

(Underwater shooting)
f 8.32 13.76 30.42
FNO 4.65 5.17 6.23
2ω 74.34 47.24 21.89
Y 8.00 8.00 8.00
TL 158.41 158.41 158.41
D7 1.822 11.822 22.822
D15 30.318 20.318 9.318
D24 2.971 6.248 14.349
D29 17.477 14.667 7.736
D39 17.277 16.811 15.641
Bf 2.104 2.104 2.104

[Lens group data]
Group Start surface End surface Focal length First lens group 1 7 67.131
Second lens group 8 15 -10.504
Third lens group 16 23 16.830
4th lens group 25 29 -14.660
5th lens group 30 39 24.633

[Position data for each lens group]
(Land shooting state)
f 10.60 19.05 45.07
Second lens group 0.000 9.999 20.998
Fourth lens group 0.000 2.938 9.622
5th lens group 0.000 0.556 3.713

(Underwater shooting)
f 8.32 13.76 30.42
Second lens group 0.000 9.999 20.998
Fourth lens group 0.463 3.744 11.845
5th lens group 0.554 1.020 2.190

[Conditional expression values]
Conditional expression (1) R1 / Enpw = 1.126
Conditional expression (2) Δ1U / Δ1A = 0.440
Conditional expression (3) Δ2U / Δ2A = 1.183
Conditional expression (4) φ1 / φw = 0.000
Conditional expression (5) R2 / TL = 0.368
R1 = 60.000
Enpw = 53.283
Δ1U = 1.636
Δ1A = 3.715
Δ2U = 11.382
Δ2A = 9.622
φ1 = 0.000
φw = 0.094
R2 = 58.295
TL = 158.41

  From Table 1, it can be seen that the amphibious variable magnification lens apparatus 10 according to the first embodiment satisfies the conditional expressions (1) to (5).

  FIG. 4 is a diagram showing various aberrations for the d-line (wavelength 587.6 nm) in the infinitely focused state in the land photographing state, based on the design value of the amphibious variable magnification lens apparatus 10 according to the first embodiment. ) Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. FIG. 5 is a diagram showing various aberrations for the d-line (wavelength 587.6 nm) in the infinite focus state in the underwater photographing state based on the design value of the amphibious variable magnification lens device 10 according to the first embodiment. ) Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  In each aberration diagram, FNO indicates an F number, and Y indicates an image height. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. The description of the aberration diagrams is the same in the other embodiments.

  From the respective aberration diagrams, the amphibious variable magnification lens apparatus 10 according to the first embodiment is well corrected for various aberrations such as distortion and curvature of field in both the land photographing state and the underwater photographing state, and has high image formation. It can be seen that it has performance.

  In the first embodiment, as a method for identifying the land shooting state and the underwater shooting state, as described above, the switch member 37 is provided in the housing 1, and the method for identifying according to the switching operation of the photographer is adopted. However, the present invention is not limited to this. For example, as shown in the amphibious variable magnification lens device 11 of FIG. 6, a method of automatically identifying the two terminals 36 by exposing them to the outside of the housing 1 and measuring the electrical resistance between the terminals, etc. It is also possible to adopt. With this configuration, convenience can be further enhanced.

(Second Embodiment)
The amphibious variable power lens apparatus according to the second embodiment will be described. As shown in FIG. 7, the amphibious variable magnification lens apparatus 100 according to the second embodiment includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power, which are arranged in order from the object side. A third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power are provided with an optical system ZL (ZL2).

  The first lens group G1 is fixed on the optical axis via the first lens group fixing portion 101a to the housing 101, and the third lens group G3 is fixed on the optical axis via the third lens group fixing portion 101b. The second lens group G2 is located between the first lens group G1 and the third lens group G3. The fourth lens group G4 and the fifth lens group G5 are arranged on the image side of the third lens group G3. It is held by a member to be described later in the housing 101 so as to be independently movable along the direction.

  A focal length change switch member 138 for changing the focal length is provided outside the housing 101. A focal length detection unit 132 that detects a focal length change request by operating the focal length change switch member 138 is disposed in the housing 101.

  A shooting state changeover switch member 137 for switching between an underwater shooting state and a land shooting state is provided outside the housing 101. In the housing 101, a shooting state identification unit 133 that identifies the shooting state changed by the shooting state changeover switch member 137 is disposed.

  A mount member 102 is fixed to the image side end portion 101c of the housing 101, and is fixed to an imaging apparatus described later by the mount member 102.

  The second lens group G2 is held by the second lens group lens frame 102a, and the first support member is disposed between the first lens group fixing part 101a and the third lens group fixing part 101b. 126 is slidably supported, and is configured to move along the optical axis by the first drive mechanism 125 based on a control signal from the control unit 135 shown in FIG.

  The fourth lens group G4 is held by a fourth lens group lens frame 104a, and this lens frame 104a is attached to a second support member 123 disposed between the third lens group fixing portion 101b and the image side end portion 101c. The second drive mechanism 121 is supported so as to be slidable and moves along the optical axis based on a control signal from the control unit 135.

  The fifth lens group G5 is held by a fifth lens group lens frame 105a, and this lens frame 5a is attached to a third support member 124 disposed between the third lens group fixing portion 101b and the image side end portion 101c. It is supported so as to be slidable, and is configured to move along the optical axis by the third drive mechanism 122 based on a control signal from the control unit 135.

  The amphibious variable magnification lens apparatus 100 according to the second embodiment includes a second lens group G2, a fourth lens group G4, and a fifth lens group G5 set for each focal length in each of a land photographing state and an underwater photographing state. The position information on the optical axis is stored in the storage unit 134. The position information of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 with the focal length not stored is processed by the control unit 135 based on the stored position information, such as interpolation processing. Can be set.

  In the amphibious variable magnification lens apparatus 100 according to the second embodiment, as shown in FIG. 8, the shooting state identified by the shooting state identification unit 133 when the shooting state changeover switch member 137 is operated is transmitted to the control unit 135. Is done. The focal length change request detected by the focal length detection unit 132 when the focal length change switch member 138 is operated is transmitted to the control unit 135.

  The control unit 135 reads position information on the optical axis of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 corresponding to the transmitted photographing state and focal length request from the storage unit 134, and The second lens group G2 via the first drive mechanism 125, the fourth lens group G4 via the second drive mechanism 121, and the fifth lens group G5 via the third drive means 122, respectively. Move to a predetermined optical axis position.

  As a result, the amphibious variable magnification lens apparatus 100 according to the second embodiment changes the shooting state by operating the shooting state changeover switch member 137, and changes the focal length by operating the focal length change switch member 138. The control unit 135 stores the positions of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 on the optical axis in the storage unit 134 at each focal length in both the land shooting state and the underwater shooting state. By setting based on the position information, it is possible to satisfactorily correct various aberrations including field curvature over the entire focal length range in both the land photographing state and the underwater photographing state.

  Next, the optical system ZL2 included in the amphibious variable magnification lens apparatus 100 according to the second embodiment will be described with reference to FIGS. The characteristic configuration of the optical system ZL2 that is common to the first embodiment is as described above.

  As shown in FIG. 9, the optical system ZL2 provided in the amphibious variable magnification lens apparatus 100 according to the second embodiment includes a first lens group G1 having a positive refractive power and a first lens unit having a negative refractive power arranged in order from the object side. 2 lens group G2, 3rd lens group G3 of positive refractive power, 4th lens group G4 of negative refractive power, and 5th lens group G5 of positive refractive power.

  The first lens group G1 includes, in order from the object side, a meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a concave surface facing the image side, and a positive meniscus lens having a convex surface facing the object side. It consists of a cemented lens with L13 and a positive meniscus lens L14 with a convex surface facing the object side.

  The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a concave surface facing the image side, a biconcave negative lens L22, a biconvex positive lens L23, and a biconcave negative lens. Lens L24. The object side surface of the negative meniscus lens L21 is aspheric.

  The third lens group G3 is composed of a cemented lens composed of a negative meniscus lens L31 having a concave surface facing the image side and a biconvex positive lens L32, and a negative meniscus lens L33 having a concave surface facing the image side. And a biconvex positive lens L34, and a biconvex positive lens L35.

  The fourth lens group G4 includes a biconcave negative lens L41, and a cemented lens of a biconcave negative lens L42 and a biconvex positive lens L43, which are arranged in order from the object side.

  The fifth lens group G5 includes a biconvex positive lens L51 arranged in order from the object side, a cemented lens of a negative meniscus lens L52 having a concave surface facing the image side, and a biconvex positive lens L53, and a biconvex lens. It comprises a positive lens L54 having a shape and a negative meniscus lens L55 having a concave surface facing the object side.

  An iris diaphragm S is disposed adjacent to the image side of the third lens group G3.

  The image plane I is formed on an image sensor (not shown), and the image sensor is composed of a CCD, a CMOS, or the like.

  In the optical system ZL2 configured as described above, the lens surface closest to the object side of the first lens group G1 has a radius of curvature that satisfies the above-described conditional expression (1), and has a convex surface facing the object side. As a result, the occurrence of distortion during underwater shooting is suppressed.

  The first lens group G1 and the third lens group G3 are always fixed.

  The second lens group G2 is moved in the image plane direction by the first drive mechanism 125 upon zooming from the wide-angle end state to the telephoto end state. However, the moving range of the second lens group G2 is different between the land photographing state and the underwater photographing state.

  The fourth lens group G4 has a land shooting state (solid arrow in FIG. 9) and an underwater shooting state (dotted arrow in FIG. 9) during zooming from the wide-angle end state to the telephoto end state by the second drive mechanism 121. ) And move to take different movement trajectories.

  The fifth lens group G5 has a land driving state (solid arrow in FIG. 9) and an underwater shooting state (dotted arrow in FIG. 9) upon zooming from the wide-angle end state to the telephoto end state by the third drive mechanism 122. ) And move to take different movement trajectories.

  In this way, by changing the movement trajectory of the fourth lens group G4 and the fifth lens group G5 between the land photographing state and the underwater photographing state, the image formation position is kept constant in the land photographing state and the underwater photographing state. It is possible to satisfactorily correct field curvature in both the photographing state and the underwater photographing state.

  In focusing from the infinity shooting state to the close-up shooting state, the fourth lens group G4 is moved in the image plane direction. In focusing, the fourth lens group G4 is moved by the second drive mechanism 121 as in the case of zooming.

  Table 2 below lists specification values of the optical system ZL2 included in the amphibious variable magnification lens apparatus 100 according to the second embodiment. Surface numbers 1 to 38 in Table 2 correspond to the optical surfaces m1 to m38 shown in FIG.

(Table 2)
[Lens data]
Surface number r d nd νd
1 100.0000 3.0000 1.516800 63.88
2 98.9800 4.0000
3 74.1356 1.8000 1.850260 32.35
4 36.0351 7.0000 1.497820 82.51
5 3038.1597 0.1000
6 36.3362 5.0000 1.729157 54.66
7 170.0064 D7 (variable)
* 8 159.7676 1.0000 1.816000 46.62
9 11.1111 5.7573
10 -57.3031 0.8000 1.816000 46.62
11 32.0791 0.2020
12 18.8298 4.0000 1.846660 23.78
13 -127.9381 0.3170
14 -90.0599 1.0000 1.816000 46.62
15 41.7316 D15 (variable)
16 22.5107 0.8000 1.834000 37.16
17 12.0861 2.5000 1.603001 65.46
18 -69.1710 1.0000
19 864.1596 1.0000 1.850260 32.35
20 16.8557 2.2000 1.603001 65.46
21 -47.4738 0.1000
22 24.2921 1.8000 1.729157 54.66
23 -67.1681 1.0000
24 ∞ (Aperture) D24 (Variable)
25 -43.6868 0.8000 1.834807 42.72
26 22.6901 0.8000
27 -25.0831 0.8000 1.834807 42.72
28 11.7100 1.8000 1.846660 23.78
29 -48.7106 D29 (variable)
30 24.1884 2.5000 1.497820 82.51
31 -58.4609 0.2000
32 40.9485 1.0000 1.834807 42.72
33 15.4156 3.5000 1.497820 82.51
34 -46.0872 8.5639
35 28.3973 2.5000 1.497820 82.51
36 -123.1319 3.7652
37 -20.5259 1.0000 1.846660 23.78
38 -54.7499 Bf
Image plane ∞

[Aspherical data]
8th surface κ = -20.0000
A4 = + 4.26826E-06
A6 = -9.97395E-09
A8 = + 1.52813E-11
A10 = -3.70867E-14
A12 = 0.00000E + 00
A14 = 0.00000E + 00

[Various data]
(Land shooting state)
f 10.41 45.47 98.00
FNO 4.60 5.15 5.89
2ω 77.37 19.45 9.06
Y 8.00 8.00 8.00
TL 135.78 135.78 135.78
D7 0.800 20.355 28.029
D15 28.052 8.497 0.823
D24 0.800 8.210 13.112
D29 16.136 9.093 6.831
Bf 18.391 18.023 15.383

(Underwater shooting)
f 9.50 16.43 38.02
FNO 4.65 4.95 5.67
2ω 64.38 39.34 17.66
Y 8.00 8.00 8.00
TL 135.78 135.78 135.78
D7 0.800 10.200 20.355
D15 28.052 18.652 8.497
D24 1.618 4.381 10.362
D29 16.899 13.919 7.212
Bf 16.809 17.026 17.762

[Lens group data]
Group Start surface End surface Focal length 1st lens group 1 7 58.171
Second lens group 8 15 -10.550
Third lens group 16 23 16.309
4th lens group 25 29 -14.362
5th lens group 30 38 24.289

[Position data for each lens group]
(Land shooting state)
f 10.41 45.47 98.00
Second lens group 0.000 19.555 27.230
Fourth lens group 0.000 7.411 12.313
5th lens group 0.000 0.368 3.008

(Underwater shooting)
f 9.50 16.43 38.02
Second lens group 0.000 9.400 19.555
Fourth lens group 0.818 3.581 9.562
5th lens group 1.582 1.365 0.629

(Values for conditional expressions)
Conditional expression (1) R1 / Enpw = 3.014
Conditional expression (2) Δ1U / Δ1A = −0.317
Conditional expression (3) Δ2U / Δ2A = 0.710
Conditional expression (4) φ1 / φw = 0.000
Conditional expression (5) R2 / TL = 0.729
R1 = 100.000
Enpw = 33.183
Δ1U = −0.953
Δ1A = 3.008
Δ2U = 8.744
Δ2A = 12.313
φ1 = 0.000
φw = 0.096
R2 = 98.98
TL = 135.78

  From Table 2, it can be seen that the amphibious variable magnification lens apparatus 100 according to the second embodiment satisfies the conditional expressions (1) to (5).

  FIG. 10 is a diagram of various aberrations for the d-line (wavelength 587.6 nm) in the infinitely focused state in the land photographing state, based on the design value of the amphibious variable magnification lens device 100 according to the second embodiment. ) Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. FIG. 11 is a diagram showing various aberrations with respect to the d-line (wavelength 587.6 nm) in an infinite focus state in an underwater photographing state, based on the design value of the amphibious variable magnification lens device 100 according to the second embodiment. ) Shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  From the respective aberration diagrams, the amphibious variable magnification lens device 100 according to the second embodiment is well corrected for various aberrations such as distortion and field curvature in both the land photographing state and the underwater photographing state, and has high image formation. It can be seen that it has performance.

  In the second embodiment, as a method for discriminating between the land photographing state and the underwater photographing state, as described above, the photographing state changeover switch member 137 is provided in the casing 101 and is identified according to the switching operation of the photographer. Although the method is adopted, it is not limited to this. For example, as shown in the amphibious variable magnification lens device 110 of FIG. 12, a method of automatically identifying two terminals 136 by exposing them to the outside of the casing 101 and measuring the electrical resistance between the terminals, etc. It is also possible to adopt. With this configuration, convenience can be further enhanced.

  Next, a camera (imaging device) 40 equipped with the amphibious variable magnification lens device according to the first and second embodiments will be described with reference to FIG. Here, a case where the amphibious variable magnification lens device 10 (see FIG. 1) according to the first embodiment is mounted will be described, but the same applies to the second embodiment.

  As shown in FIG. 13, the camera 40 is a lens-exchangeable amphibious camera that detachably holds the amphibious variable magnification lens device 10 according to the first embodiment. In this camera 40, light from a subject (not shown) is collected by the optical system ZL 1 of the amphibious variable magnification lens device 10 and imaged on the image sensor 41. The subject image formed on the image sensor 41 is converted into a video signal by an electric circuit (not shown) and displayed on the monitor screen 42 so that it can be observed by the photographer. The photographer operates the switch member 37 (see FIG. 1) to set the shooting state, operates the operation member 31 (see FIG. 1) to set the focal length, and then half-presses a release button (not shown). While observing the subject image via the monitor screen 42, the shooting composition is determined. Subsequently, when the release button is fully pressed by the photographer, in the camera 40, light from the subject is received by the image sensor 41, and a photographed image is acquired and recorded in a memory (not shown).

  According to the amphibious camera 40 according to the present embodiment having the above-described configuration, the amphibious zoom lens device 10 according to the first embodiment is provided. In both cases, it is possible to realize a camera capable of zooming and having excellent optical performance.

  The camera 40 shown in FIG. 13 is not only a type in which the amphibious zoom lens device 10 is detachably mounted, but also a type in which the camera body and the amphibious zoom lens device 10 are integrally formed. It may be a thing. Further, the camera 40 may be a so-called single-lens reflex camera having a quick return mirror or a video camera that mainly performs moving image shooting.

  Then, the manufacturing method of the amphibious variable magnification lens apparatus which concerns on 1st and 2nd embodiment is demonstrated, referring FIG. Here, although the case where the amphibious variable magnification lens apparatus 10 (refer FIG. 1) which concerns on 1st Embodiment is manufactured is demonstrated, it is the same also in 2nd Embodiment.

  First, a first lens group having lenses arranged in order from the object side along the optical axis and having a lens surface with the convex surface facing the object side closest to the object side, and at least three moving lens groups are included. In addition, each lens is arranged in the housing 1 (step ST10). At this time, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed and the moving lens group (for example, the second lens group G2, the fourth lens group G4, and the fifth lens group G5) is fixed. The lenses are arranged so as to move independently from each other (step ST20). Further, among the moving lens groups, at least two lens groups (for example, the fourth lens group G4 and the fifth lens group G5) have different movement loci at the time of zooming in the land photographing state and the underwater photographing state. Then, each lens is arranged (step ST30).

  As an example of the lens arrangement in this embodiment, in the amphibious variable magnification lens apparatus 10 according to the first embodiment, as described above (see FIG. 3), as the first lens group G1, objects are sequentially arranged from the object side. A meniscus lens L11 having a convex surface on the side, a cemented lens of a negative meniscus lens L12 having a concave surface on the image side and a positive lens L13 having a biconvex shape, and a positive meniscus lens L14 having a convex surface on the object side. And placed in the housing 1. As the second lens group G2, in order from the object side, a cemented lens of a positive meniscus lens L21 having a convex surface facing the object side and a negative meniscus lens L22 having a concave surface facing the image side, a biconcave negative lens L23, A cemented lens of a biconvex positive lens L24 and a biconcave negative lens L25 is disposed in the housing 1. As the third lens group G3, in order from the object side, a cemented lens of a negative meniscus lens L31 having a concave surface facing the image side and a biconvex positive lens L32, and a biconvex positive lens L33 and a concave surface on the object side. A cemented lens with the directed negative meniscus lens L34 and a biconvex positive lens L35 are arranged in the housing 1. As the fourth lens group G4, a biconcave negative lens L41, and a cemented lens of a biconcave negative lens L42 and a biconvex positive lens L43 are arranged in the housing 1 in order from the object side. As the fifth lens group G5, a cemented lens of a biconvex positive lens L51, a biconvex positive lens L52, and a negative meniscus lens L53 having a concave surface facing the object side, arranged in order from the object side, and the image side A cemented lens composed of a negative meniscus lens L54 having a concave surface facing the lens and a biconvex positive lens L55, and a negative meniscus lens L56 having a concave surface facing the object side are disposed in the housing 1.

  According to such a manufacturing method, the amphibious variable power lens apparatus 10 having a simple configuration and capable of zooming in both the land shooting state and the underwater shooting state and having excellent optical performance is manufactured. Can do.

  In order to make the present invention easy to understand, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this.

  For example, in each of the above embodiments, an optical system having a five-group configuration has been described. However, the present invention can be applied to other group configurations such as a four-group configuration and a six-group configuration or more. 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 refers to a portion having at least one lens separated by an air interval that changes during focusing or zooming. In the case of a configuration of six groups or more, the number of moving lens groups is not limited to three, and four or more moving lens groups are applicable. Further, when there are four or more moving lens groups, the storage units 34 and 134 can obtain the same effects as those of the above embodiment by storing the positional information of the two to four moving lens groups. it can

  In each embodiment, 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. This focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (using an ultrasonic motor or the like). In particular, the fourth lens group G4 is preferably a focusing lens group.

  In each embodiment, the lens surface may be formed of a spherical surface, a flat surface, or an aspheric surface. When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and optical performance deterioration due to errors in processing and assembly adjustment can be 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.

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

Changeover switch 10, 11, 100, 110 Amphibious variable power lens apparatus 1, 101 Housing 21, 125 First drive mechanism 22, 121 Second drive mechanism 31 Operation member (for changing focal length)
2a Lens frame (movement mechanism)
2b pin (movement mechanism)
31a Cam groove (moving mechanism)
32, 132 Focal length detection unit 33, 133 Shooting state identification unit 34, 134 Storage unit 35, 135 Control unit 37, 137 Switch member (for shooting state switching)
40 Amphibious camera (imaging device)
41 Image sensor 42 Monitor screen 122 Third drive mechanism 138 Switch member (for changing focal length)
ZL (ZL1, ZL2) Optical system G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group S Aperture F Filter group I Image surface

Claims (11)

An amphibious variable power lens device capable of photographing underwater and on land,
A first lens group having lenses that are arranged in order from the object side along the optical axis and whose lens surface closest to the object side has a convex surface facing the object side; and at least three moving lens groups;
During zooming from the wide-angle end state to the telephoto end state, the first lens group is fixed, and the moving lens group moves independently of each other,
Among the moving lens groups, at least two lens groups have different movement trajectories at the time of zooming in the land shooting state and the underwater shooting state. The amphibious variable power lens apparatus according to claim 1, wherein the following conditional expression is satisfied.
0.80 <R1 / Enpw <4.00
However,
R1: radius of curvature of the lens surface closest to the object side of the first lens group,
Enpw: Distance on the optical axis from the most object-side lens surface of the first lens group to the entrance pupil position in the infinity photographing state at the wide-angle end state in the land photographing state of the amphibious variable magnification lens apparatus. The amphibious variable power lens apparatus according to claim 1 or 2, wherein the following conditional expression is satisfied.
−0.90 <Δ1U / Δ1A <0.90
0.20 <Δ2U / Δ2A <2.00
However,
Δ1U: Of the at least two moving lens groups, the lens group located closest to the image side is required to change from the infinity shooting state at the wide-angle end state in the underwater shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ1A: Of the at least two moving lens groups, the lens group located closest to the image side needs to change from the infinity shooting state at the wide-angle end state in the land shooting state to the infinity shooting state at the telephoto end state. Amount of movement (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is attached with a negative sign),
Δ2U: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the underwater shooting state to the infinity shooting state in the telephoto end state. The amount of movement required for the change (however, the amount of movement in the image plane direction is given a positive sign and the amount of movement in the object direction is attached with a negative sign),
Δ2A: Of the at least two moving lens groups, the second lens group counted from the image side changes from the infinity shooting state in the wide-angle end state in the land shooting state to the infinity shooting state in the telephoto end state. The amount of movement required to change the distance (however, the amount of movement in the image plane direction is given a positive sign, and the amount of movement in the object direction is assigned a negative sign). An identification unit for distinguishing between a land shooting state and an underwater shooting state;
An operation unit for changing the focal length;
A focal length detection unit for detecting the focal length changed by the operation unit;
A moving mechanism for moving at least one moving lens group among the moving lens groups along the optical axis in conjunction with an operation of the operation unit;
At least two independent driving mechanisms for moving at least two moving lens groups other than the lens group moving through the moving mechanism among the moving lens groups, respectively, along the optical axis;
A storage unit that stores positions on the optical axis set for each focal length in each of a land shooting state and an underwater shooting state of at least two moving lens groups that move via the drive mechanism;
Based on outputs from the identification unit and the focal length detection unit, the driving of the at least two drive mechanisms is controlled so that the at least two moving lens groups move to a predetermined position stored in the storage unit. The amphibious variable power lens apparatus according to any one of claims 1 to 3, further comprising a control unit. An identification unit for distinguishing between a land shooting state and an underwater shooting state;
An operation unit for changing the focal length;
A focal length detection unit for detecting the focal length changed by the operation unit;
At least three independent driving mechanisms for moving at least three of the moving lens groups along the optical axis, respectively;
A storage unit that stores positions on the optical axis set for each focal length in each of a land shooting state and an underwater shooting state of at least three moving lens groups that move via the drive mechanism;
Based on the outputs from the identification unit and the focal length detection unit, the driving of the at least three drive mechanisms is controlled so that the at least three moving lens groups move to predetermined positions stored in the storage unit. The amphibious variable power lens apparatus according to any one of claims 1 to 3, further comprising a control unit. 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, a fourth lens group having a negative refractive power, and a positive refractive power arranged in order from the object side. A fifth lens group,
The at least one moving lens group that moves via the moving mechanism includes the second lens group;
The amphibious variable according to claim 4, wherein the at least two moving lens groups that move via the at least two drive mechanisms include the fourth lens group and the fifth lens group. Double lens device. 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, a fourth lens group having a negative refractive power, and a positive refractive power arranged in order from the object side. A fifth lens group,
The at least three moving lens groups that move via the at least three drive mechanisms include the second lens group, the fourth lens group, and the fifth lens group. The amphibious variable-power lens apparatus according to 5. On the most object side, it has a meniscus lens with a convex surface facing the object side,
The amphibious variable power lens apparatus according to any one of claims 1 to 7, wherein the following conditional expression is satisfied.
−0.15 <φ1 / φw <0.15
However,
φ1: refractive power of the meniscus lens in air
φw: Refracting power of the amphibious variable power lens apparatus in the wide-angle end state in the land photographing state. On the most object side, it has a meniscus lens with a convex surface facing the object side,
The amphibious variable power lens apparatus according to any one of claims 1 to 7, wherein the following conditional expression is satisfied.
0.30 <R2 / TL <0.90
However,
R2: radius of curvature of the image side surface of the meniscus lens,
TL: Distance on the optical axis from the lens surface closest to the object side to the imaging surface of the amphibious variable magnification lens apparatus.   An image pickup apparatus comprising the amphibious variable power lens apparatus according to any one of claims 1 to 9. A method of manufacturing an amphibious variable magnification lens apparatus capable of photographing underwater and on land,
A first lens group having lenses that are arranged in order from the object side along the optical axis and whose lens surface closest to the object side has a convex surface facing the object side; and at least three moving lens groups;
During zooming from the wide-angle end state to the telephoto end state, the first lens group is fixed, and the moving lens group moves independently of each other,
Among the moving lens groups, at least two lens groups have different movement loci at the time of zooming in the land shooting state and the underwater shooting state,
A method for manufacturing an amphibious variable power lens apparatus, wherein each lens is disposed in a housing.

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