Optical instrument, control method of optical instrument and program

Abstract

To provide an optical instrument in which exposure flicker of an image can be reduced in a zooming operation.SOLUTION: An optical instrument (100) comprises: an optical system that comprises an aperture diaphragm (102) having variable aperture diameter, and in which a focal distance and an F value are variable; and control means (120) that controls the aperture diameter for the F value to become a target F value on the basis of the focal distance. The control means control the aperture diameter to be close to first target diameter when a difference between the aperture diameter and the first target diameter corresponding to a target F value is smaller than a predetermined amount, and changes the first target diameter to second target diameter for the difference to become smaller than the predetermined amount when the difference between the aperture diameter and the first target diameter is larger than the predetermined amount.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical device, a control method for an optical device, and a program. [Background technology]

[0002] Generally, the F-number of an imaging optical system is determined according to the aperture diameter and focal length (zoom state). In particular, when shooting video, it is necessary to control the aperture unit so that the F-number remains constant during zooming. Patent Document 1 discloses an optical device that, when controlling the aperture unit according to the zoom state, slows the drive speed of the aperture unit during video shooting compared to still image shooting. Patent Document 2 discloses an optical device that suppresses exposure flicker by controlling the drive speed of the aperture unit according to the remaining drive amount of the aperture unit while changing the zoom state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-194601 [Patent Document 2] Japanese Patent Application Publication No. 2020-34779 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the optical devices disclosed in Patent Documents 1 and 2 may not be able to reduce exposure flicker in an image when a zoom reversal operation is performed.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical device that can reduce exposure flicker of an image during a zoom operation. [Means for solving the problem]

[0006] An optical device according to one aspect of the present invention comprises an optical system equipped with an aperture stop having a variable aperture diameter, and having a variable focal length and F-number, and a control means for controlling the aperture diameter based on the focal length so that the F-number becomes a target F-number, wherein the control means controls the aperture diameter to approach the first target diameter when a difference between the aperture diameter and a first target diameter corresponding to the target F-number is smaller than a predetermined amount, and changes the first target diameter to a second target diameter when the difference between the aperture diameter and the first target diameter is larger than the predetermined amount so that the difference becomes smaller than the predetermined amount.

[0007] Other objects and features of the present invention will be described in the following embodiments. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an optical device that can reduce exposure flicker of an image during a zoom operation. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 10 is an explanatory diagram of aperture drive during zoom operation as a comparative example. [Figure 2] FIG. 10 is an explanatory diagram of the amount of error in the aperture position during zoom operation as a comparative example. [Figure 3] FIG. 2 is a block diagram of an imaging system according to each embodiment. [Figure 4] 10 is a table showing aperture open positions for each focal length in each embodiment. [Figure 5] FIG. 4 is an explanatory diagram of an aperture tracking method during zoom operation in the first embodiment. [Figure 6] FIG. 4 is an explanatory diagram of diaphragm driving during zoom operation in the first embodiment. [Figure 7] FIG. 4 is an explanatory diagram of the amount of error in the aperture position during zoom operation in the first embodiment. [Figure 8] 4 is a flowchart of aperture control in the first embodiment. [Figure 9] FIG. 10 is an explanatory diagram of an aperture tracking method during zoom operation in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] <Explanation of Comparative Example> First, a comparative example of each embodiment will be described with reference to Figures 1 and 2 regarding exposure flicker of an image when a zoom inversion operation is performed in a lens unit. Here, the zoom inversion operation is, for example, an operation in which a zoom operation is performed from the TELE direction (telephoto side) to the WIDE direction (wide-angle side) until a certain time, and then the zoom operation (zoom position) is turned back (inverted) to return to the TELE direction.

[0012] FIG. 1 is an explanatory diagram of aperture drive during zoom operation as a comparative example. FIG. 1 shows the target position (target diameter) of the aperture and the tracking state of the aperture blades when zooming is performed when a predetermined target F-number (target F-number) is set (when the aperture blades are positioned at the predetermined F-number). In FIG. 1, the horizontal axis represents elapsed time t, and the vertical axis represents the aperture position (aperture opening diameter). Also in FIG. 1, the solid line represents the target aperture position (F-number tracing position, first target position (first target diameter)), and the dashed dotted line represents the current aperture position (actual aperture opening diameter, current position).

[0013] Figure 1 shows the state in which zooming is performed as follows: First, up to time t1, zooming is performed from the TELE direction (telephoto side) to the WIDE direction (wide-angle side). Next, in the section from time t1 to time t3, the zooming (zoom position (focal length)) is turned back (reversed) to move toward the TELE direction. Then, at time t3 (at an intermediate zoom position), the zooming stops.

[0014] To maintain a predetermined target F-number (target F-number), the aperture position must track to the position indicated by the solid line in FIG. 1. In this comparative example, in order to maintain the F-number (target F-number) during zoom operation, aperture tracking control is performed so that the aperture approaches the target aperture position (first target position) indicated by the solid line. Here, in the section up to time t1, as time passes, the current aperture position moves away from the target aperture position. This situation occurs particularly in video mode, where the aperture is driven at a relatively slow speed to suppress exposure flicker caused by noise and sudden changes in behavior, and so this situation occurs during fast zoom operation.

[0015] At time t1, the zoom operation reverses, and the target aperture position approaches the current aperture position. However, at this time, the current aperture position has not yet reached the target aperture position. Therefore, aperture control continues to move toward the target aperture position. At time t2, the target aperture position and the current aperture position intersect. After time t2, the current aperture position overtakes the target aperture value, and the aperture drive direction reverses, moving toward the target aperture value again.

[0016] Figure 2 is an explanatory diagram of the difference (aperture error, aperture position error) between the target aperture position and the current aperture position in the situation of Figure 1. In Figure 2, the horizontal axis represents elapsed time t, and the vertical axis represents aperture error (exposure difference). The aperture error is an error in the F-number, and is generally a factor that leads to an exposure difference.

[0017] As shown in Figure 2, until time t2 when the zoom operation is reversed, the current aperture position has not reached the target aperture position, resulting in a tendency toward overexposure. From time t1 to time t2, the aperture error amount suddenly decreases, resulting in a sudden change in exposure. In the section from time t2, the current aperture position overtakes the target aperture position, resulting in a tendency toward underexposure, resulting in variations in brightness and darkness of the exposure.

[0018] As can be seen from Figure 2, simply controlling the aperture diameter so as to approach the target aperture position can result in exposure flicker in the image during zooming. Therefore, each embodiment provides an optical device that reduces exposure flicker in the image during zooming. Each embodiment will be described in detail below.

[0019] <Imaging system> First, an imaging system 10 in each embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram of the imaging system 10. The imaging system 10 is configured to include a lens unit (lens device, optical equipment) 100 and a camera body (imaging device) 200 to which the lens unit 100 is detachably and communicably attached. However, each embodiment is not limited to this, and can also be applied to an imaging device in which the lens unit and camera body are integrally configured.

[0020] Lens unit 100 has an imaging optical system. The imaging optical system includes, arranged in this order from the subject side (left side in FIG. 1) to the image side (right side), a field lens 101, an aperture unit (aperture stop) 102, and a focus lens 103. In each embodiment, the imaging optical system includes aperture unit 102 with a variable aperture diameter, and the focal length and F-number are variable.

[0021] The focus lens 103 adjusts the focus of the imaging optical system by moving in a direction along the optical axis OA (optical axis direction). The aperture unit 102 has a variable aperture opening diameter (aperture position) to adjust the amount of light passing through the imaging optical system. The aperture position is a position where a predetermined aperture index value (F-number or T-number) can be achieved.

[0022] The focus lens 103 is held by a lens frame (not shown) and a guide shaft (not shown) so as to be movable in the optical axis direction, and is driven in the optical direction by a driving force from a stepping motor 111. The diaphragm unit (aperture diaphragm) 102 changes the diaphragm aperture diameter by driving diaphragm blades 102a and 102b in the opening and closing directions by a driving force from a stepping motor 109. In the following description, driving the diaphragm blades 102a and 102b (driving to change the diaphragm aperture diameter) is referred to as driving the diaphragm unit 102.

[0023] The lens unit 100 has a lens microcomputer (lens microcontroller, control means) 120. Stepping motors 109 and 111 are driven by drive circuits 108 and 110, respectively, in accordance with commands from the lens microcomputer 120. The lens microcomputer 120 also performs control in response to various lens control commands transmitted from the camera body 200 (camera microcomputer 206). Communication between the lens unit 100 and the camera microcomputer 206 is performed via communication units 121 and 207.

[0024] The memory unit 122 stores the program body processed by the lens microcomputer 120 and various temporary storage variables. The image sensor 201 of the camera body 200 receives light that has passed through the imaging optical system of the lens unit 100 and outputs an imaging signal. The signal processing unit 202 converts the imaging signal from the image sensor 201 into digital data and outputs image data. The recording processing unit 203 records the image data. The display unit 204 displays information necessary for imaging. The operation unit 205 accepts imaging operations.

[0025] <Aperture unit> In the aperture unit 102, the positions of the aperture blades 102a and 102b in the opening and closing direction are managed by accumulating the drive amount of the stepping motor 109 in an internal memory (not shown) within the lens microcomputer 120 as position information of the aperture unit 102. An aperture control signal is output to the drive circuit 108 based on the position information for the aperture unit 102. The drive circuit 108 drives the stepping motor 109 in accordance with the aperture control signal. In each embodiment, the aperture unit 102 is designed so that the aperture opening diameter changes in 1 / 32 steps by driving the stepping motor 109 one step. However, each embodiment is not limited to this, and other drive methods may be used.

[0026] <Zoom control ring> The zoom operation ring 104 is an operation member provided on the lens unit 100. The zoom operation ring 104 changes (adjusts) the focal length (zoom position) of the lens unit 100 in response to a user operation. Note that the operation member is not limited to a member that is manually operated by the user, and may be a member that is electrically driven in response to a user operation.

[0027] The zoom operation ring 104 is mechanically coupled to the field lens 101. When the user operates the zoom operation ring 104, the field lens 101 moves in conjunction with it in the direction of the optical axis, thereby changing the focal length. The rotational position of the zoom operation ring 104 is detected by a position detection circuit 107 receiving an output signal from a rotation detection sensor 105, which is composed of a photoreflector or the like. With this configuration, the current focal length can be determined from the rotational position of the zoom operation ring 104.

[0028] <Relationship between zoom operation and aperture diameter> As described above, the F-number of the imaging optical system is determined according to the aperture diameter and focal length (zoom position, zoom state). FIG. 4 is a diagram showing the maximum aperture position (maximum aperture position) for each focal length (zoom position) of the lens unit 100 in each embodiment. FIG. 4 is a table showing the maximum aperture position in each of 32 zones divided into focal lengths from TELE (telephoto end) to WIDE (wide-angle end). Each value indicates the step position of the stepping motor 109, and indicates that driving the stepping motor 109 to the step position shown in FIG. 4 in each zone enables driving to the maximum aperture position for that focal length. Note that the lens unit 100 in each embodiment is designed so that the maximum aperture F-number remains constant regardless of the focal length, but this is not limited to this.

[0029] In this embodiment, the lens microcomputer 120 monitors the output of the position detection circuit 107 at regular intervals (predetermined intervals) and monitors the operating position of the zoom operation ring 104, i.e., changes in focal length. The lens microcomputer 120 monitors changes in focal length at regular intervals and controls the aperture unit 102 to maintain a predetermined F-number by adjusting the aperture opening diameter in accordance with changes in focal length. In other words, the lens microcomputer 120 controls the aperture diameter based on the focal length so that the F-number becomes the target F-number.

[0030] When controlling the aperture position at the maximum aperture F-number, the lens microcomputer 120 can maintain the maximum aperture F-number by continuing to drive the stepping motor 109 to the maximum aperture step position for each focal length, referring to the table shown in FIG. 4 in accordance with the zoom operation. Furthermore, even when maintaining a specific stopped-down F-number, the lens microcomputer 120 controls the stepping motor 109 to maintain a position stopped down from the maximum aperture position by the difference in steps from the maximum aperture F-number. Furthermore, the maximum aperture F-number may vary slightly depending on the focus position. Therefore, when maintaining a specific stopped-down F-number, the lens microcomputer 120 determines the difference in steps from the maximum aperture position, taking into account the amount of change in the maximum aperture F-number for each focus position.

[0031] (First embodiment) Next, a first embodiment of the present invention will be described. First, a method of aperture tracking during zoom operation in this embodiment will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram of the aperture tracking method during zoom operation. Fig. 5 shows how the lens microcomputer 120 controls the F-number to be maintained at a constant cycle. In Fig. 5, the horizontal axis represents elapsed time t, and the vertical axis represents aperture position.

[0032] In Figure 5, the aperture position (aperture position corresponding to a predetermined F-number) that should be maintained to maintain a predetermined F-number based on the focal length and focus position at a certain periodic timing (Tn) is designated as a target aperture position (first target position) Ptrn. The current aperture position (actual aperture position) at this time is designated as Pn. Here, the zoom operation ring 104 is being operated quickly, causing the aperture blades 102a and 102b to be slow to follow. The difference between the target aperture position Ptrn and the current aperture position Pn at this time corresponds to the current error amount in Figure 5.

[0033] In this embodiment, the second target position (second target diameter) Ptgtn is calculated with a target position obtained by reducing the current error amount by 20% in the next cycle. The purpose of this embodiment is to reduce exposure flicker caused by changes in the difference amount (current error amount) between the target aperture position Ptrn and the current aperture position Pn. Therefore, the second target position must be set so that the current difference amount gradually decreases. Therefore, the next difference amount is not only set to a value reduced from the current difference amount, but also set to the over-excess side if the current aperture tends to be over-excessive, or set to the under-excess side if the current aperture tends to be under-excessive. In other words, if the current aperture position Pn is closer to the target aperture position Ptrn than the target aperture position Ptrn, the second target position Ptgtn is also set to the smaller aperture side, and if the current aperture position Pn is closer to the target aperture position Ptrn than the target aperture position Ptrn, the second target position Ptgtn is also set to the larger aperture side.

[0034] In the next cycle, the lens microcomputer 120 sets the target position of the aperture unit 102 to the second target position Ptgtn and controls the stepping motor 109. By repeating this process, the current aperture position Pn approaches the target aperture position Ptrn.

[0035] At this time, the target aperture position during zoom operation described with reference to Fig. 1 and the current aperture position in this embodiment are as shown in Fig. 6. Fig. 6 is an explanatory diagram of aperture drive during zoom operation in this embodiment. In Fig. 6, the horizontal axis represents elapsed time t, and the vertical axis represents aperture position (aperture diameter). Also in Fig. 6, the solid line represents the trajectory (F-number tracing trajectory) of the target aperture position (F-number tracing position), and the dashed-dotted line represents the current aperture position (actual aperture diameter).

[0036] Figure 6 shows the same zoom operation as in Figure 1. That is, the zoom operation is performed from the TELE direction (telephoto side) to the WIDE direction (wide-angle side) (the zoom position moves in the first direction). Then, in the section from time t1 to time t3, the zoom operation is reversed so that it moves in the TELE direction (the zoom position is reversed to the second direction).

[0037] In this embodiment, as shown in FIG. 6 , after time t1 when the zoom operation (zoom position) is reversed, the current aperture position is driven in a direction away from the target aperture position (first target position). That is, when the movement of the zoom position (the direction of change in focal length) changes from a first direction to a second direction opposite to the first direction, the lens microcomputer 120 changes the first target position to the second target position, thereby controlling the aperture diameter so that the current aperture position moves away from the first target position. In other words, the first target position is a position (diameter) changed in the first direction based on the aperture diameter (current aperture position), and the second target position is a position (diameter) changed in the second direction based on the aperture diameter (current aperture position). This is because the second target position is set so that the amount of change in the error between the current aperture position and the target aperture position gradually decreases (for example, by a predetermined value or a predetermined rate). Note that in this embodiment, the first direction is the WIDE direction and the second direction is the TELE direction, but this is not limited thereto. The first direction may be the TELE direction and the second direction may be the WIDE direction.

[0038] Fig. 7 is an explanatory diagram of the difference between the target aperture position and the current aperture position (aperture error amount, aperture position error) in the situation of Fig. 6. In Fig. 7, the horizontal axis represents elapsed time t, and the vertical axis represents aperture error amount (exposure difference). In Fig. 7, compared to Fig. 2, it can be seen that the abrupt change in aperture error amount and the over / under hunting phenomenon have been improved.

[0039] Next, aperture control in this embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart of aperture control in this embodiment. Each step in Fig. 8 is mainly executed by the lens microcomputer 120 at regular intervals.

[0040] First, in step S1, the lens microcomputer 120 acquires information about the zoom position (the focal length of the lens unit 100). Next, in step S2, the lens microcomputer 120 acquires information about the focus position. Next, in step S3, the lens microcomputer 120 calculates the target aperture position (the aperture position on the solid line in FIG. 6, the first target position). The target aperture position is calculated based on the information about the zoom position acquired in step S1, the information about the focus position acquired in step S2, and the target F-number set in response to a user operation. Based on the zoom position, focus position, and target F-number, the lens microcomputer 120 controls the aperture diameter so that the aperture approaches the first target position to maintain the target position. In this embodiment, the target position is calculated using the focus position in addition to the zoom position and target F-number. Depending on the lens design, the effective F-number may change depending on the focus position, so it may be preferable to fine-tune the aperture diameter depending on the focus position. Specifically, it is appropriate to provide a data string (e.g., a data format such as that shown in FIG. 4) indicating the correction amount for each focus position and to reference this data and add it to the target position calculation.

[0041] Next, in step S4, the lens microcomputer 120 acquires the current aperture position (the aperture position on the dashed line in FIG. 6). Next, in step S5, the lens microcomputer 120 calculates the difference (aperture error amount) between the target aperture position calculated in step S3 and the current aperture position acquired in step S4.

[0042] Next, in step S6, the lens microcomputer 120 determines whether the aperture error amount calculated in step S5 is equal to or greater than a predetermined amount. In this embodiment, the lens microcomputer 120 determines at predetermined intervals whether the aperture error amount is greater than the predetermined amount. In this embodiment, the predetermined amount is, for example, 1 / 16 stops, but is not limited to this. If the aperture error amount is equal to or greater than the predetermined amount, the process proceeds to step S7.

[0043] In step S7, the lens microcomputer 120 calculates a second target position as the target aperture position. Subsequently, in step S8, the lens microcomputer 120 starts driving the aperture unit 102 (aperture drive) toward the second target position calculated in step S7. That is, the lens microcomputer 120 updates the drive target position from the first target position, which is the aperture position on the solid line in FIG. 6, to a second target position different from the first target position.

[0044] In this embodiment, when the difference between the aperture diameter (current aperture position) and the first target position is greater than a predetermined amount, the lens microcomputer 120 changes the first target position to a second target position different from the first target position so that the difference becomes smaller than the predetermined amount. Here, the current aperture position means the aperture diameter at any control timing.

[0045] On the other hand, if the aperture error amount is not equal to or greater than the predetermined amount in step S7, the process proceeds to step S9. In step S9, the lens microcomputer 120 starts driving the aperture toward the first target position calculated in step S3. That is, the lens microcomputer 120 updates the first target position so as to maintain the drive target position at the aperture position on the solid line in FIG.

[0046] Thus, in this embodiment, when the difference between the aperture diameter and the first target diameter corresponding to the target F-number is smaller than a predetermined amount, the lens microcomputer 120 controls the aperture diameter to approach the first target diameter. On the other hand, when the difference between the aperture diameter and the first target diameter is larger than a predetermined amount, the lens microcomputer 120 changes the first target diameter to the second target diameter so that the difference becomes smaller than the predetermined amount.

[0047] In this embodiment, when calculating the second target position, the change in the aperture error amount is calculated as a percentage. At this time, if the aperture error amount becomes small, it is preferable to perform control to quickly converge the error by setting the target aperture position directly to the target position. For this reason, in step S6 in Figure 8, if the aperture error amount is less than a predetermined amount, the target aperture position is set on the assumption that even if the aperture is driven to the target aperture position in one go, the change in exposure will be difficult to see.

[0048] In this embodiment, the second target position is calculated using the current aperture error amount. That is, the lens microcomputer 120 uses the aperture error amount determined at the first timing (Tn) to determine the second target position to be used for control at the second timing (Tn+1) after the first timing. However, this embodiment is not limited to this, and the same effect can be achieved by calculating the second target position using, for example, the previous aperture error amount. That is, the lens microcomputer 120 may use the aperture error amount determined at the first timing (Tn-1) before the second timing (Tn) to determine the second target position to be used for control at the third timing (Tn+1) after the second timing.

[0049] (Second embodiment) Next, a second embodiment of the present invention will be described. A method of aperture tracking during zoom operation in this embodiment will be described with reference to Fig. 9. Fig. 9 is an explanatory diagram of the aperture tracking method during zoom operation. Fig. 9 shows the state of control for maintaining the F-number at a constant cycle in the lens microcomputer 120. In Fig. 5, the horizontal axis represents elapsed time t, and the vertical axis represents aperture position.

[0050] This embodiment differs from the first embodiment in that the second target position is set based on the next predicted position of the target aperture position. In FIG. 9, Ptrn+1 is the target aperture position (next predicted position) at time Tn+1. The next predicted position can be calculated, for example, by linearly interpolating the previous target aperture position Ptrn-1 and the current target aperture position (first target position) Ptrn. Then, a difference (a value obtained by multiplying the current error amount by 0.8) is calculated by subtracting 20% ​​from the current error amount, which is the difference between the current target aperture position (first target position) Ptrn and the current aperture position Pn, and the second target position Ptgtn is set based on the next predicted position Ptrn+1. Note that the second target position is set to have the same relationship as the relationship between the target aperture position and the current aperture position, as in the first embodiment. In this case, the target aperture position during the zoom operation described with reference to FIG. 1 and the current aperture position in this embodiment are as shown in FIG. 6, as in the first embodiment.

[0051] In this way, the lens microcomputer 120 uses the first target positions at the first timing (Tn-1) and the second timing (Tn) to calculate a predicted target position (next predicted position) that corresponds to the first target position at the third timing (Tn+1). Then, the lens microcomputer 120 uses the predicted target position to determine a second target position to be used for control at the third timing. The method of this embodiment can also achieve the same effects as the first embodiment. (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0052] According to each embodiment, it is possible to provide an optical device, a control method for an optical device, and a program that can reduce exposure flicker in an image during zooming. The configuration and method of each embodiment are particularly effective during zooming inversion.

[0053] The disclosure of each embodiment includes the following configurations and methods. (Configuration 1) an optical system having an aperture stop with a variable aperture diameter and variable focal length and F-number; a control means for controlling the aperture diameter based on the focal length so that the F-number becomes a target F-number, The control means When a difference between the aperture diameter and a first target diameter corresponding to the target F-number is smaller than a predetermined amount, the aperture diameter is controlled so as to approach the first target diameter; an optical device, characterized in that, when the difference between the opening diameter and the first target diameter is larger than the predetermined amount, the first target diameter is changed to a second target diameter so that the difference becomes smaller than the predetermined amount. (Configuration 2) The optical device described in configuration 1, characterized in that when the direction of change of the focal length changes from a first direction to a second direction opposite to the first direction, the control means controls the aperture diameter so that the aperture diameter moves away from the first target diameter by changing the first target diameter to the second target diameter. (Configuration 3) the first target diameter is a diameter that changes in the first direction based on the opening diameter, 3. The optical device according to configuration 2, wherein the second target diameter is a diameter that changes in the second direction with the aperture diameter as a reference. (Configuration 4) The optical device according to any one of configurations 1 to 3, characterized in that, when the difference is greater than the predetermined amount, the control means determines the second target diameter so that the difference decreases by a predetermined value or a predetermined rate. (Configuration 5) 5. The optical device according to any one of configurations 1 to 4, wherein the control means determines whether the difference is greater than the predetermined amount at predetermined intervals. (Configuration 6) 6. The optical device according to any one of configurations 1 to 5, further comprising an operation member that changes the focal length in response to a user operation. (Configuration 7) The optical device described in any one of configurations 1 to 6, characterized in that the control means uses the difference determined at a first timing to determine the second target diameter to be used for control at a second timing after the first timing. (Configuration 8) The optical device described in any one of configurations 1 to 6, characterized in that the control means determines the second target diameter to be used for control at a third timing after the second timing, using the difference determined at a first timing before the second timing. (Configuration 9) The control means calculating a predicted target diameter corresponding to the first target diameter at a third timing later than the second timing using the first target diameter at a first timing and a second timing later than the first timing; 7. The optical device according to any one of configurations 1 to 6, wherein the predicted target diameter is used to determine the second target diameter used for control at the third timing. (Configuration 10) 10. The optical device according to any one of configurations 1 to 9, wherein the control means controls the aperture diameter based on a focus position. (Method 1) A method for controlling an optical device having an aperture unit with a variable aperture diameter, comprising: an acquisition step of acquiring a zoom position, a focus position, and a target F-number; a control step of controlling the aperture diameter based on the zoom position, the focus position, and the target F-number, In the control step, controlling the aperture diameter so as to approach a first target position for maintaining the target F-number; A control method characterized by changing the first target position to a second target position different from the first target position so that the difference becomes smaller than the predetermined amount when the difference between the current position of the opening diameter and the first target position is larger than a predetermined amount. (Configuration 11) A program that causes a computer to execute the method for controlling an optical device according to Method 1.

[0054] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0055] 100 Lens unit (optical equipment) 102 Aperture unit 120 Lens microcomputer (control means)

Claims

1. an optical system having an aperture stop with a variable aperture diameter and variable focal length and F-number; a control means for controlling the aperture diameter based on the focal length so that the F-number becomes a target F-number, The control means When a difference between the aperture diameter and a first target diameter corresponding to the target F-number is smaller than a predetermined amount, the aperture diameter is controlled so as to approach the first target diameter; an optical device, characterized in that, when the difference between the opening diameter and the first target diameter is larger than the predetermined amount, the first target diameter is changed to a second target diameter so that the difference becomes smaller than the predetermined amount.

2. The optical device according to claim 1, characterized in that, when the direction of change of the focal length changes from a first direction to a second direction opposite to the first direction, the control means controls the aperture diameter so that the aperture diameter moves away from the first target diameter by changing the first target diameter to the second target diameter.

3. the first target diameter is a diameter that changes in the first direction based on the opening diameter, 3. The optical device according to claim 2, wherein the second target diameter is a diameter that varies in the second direction with the aperture diameter as a reference.

4. 4. The optical device according to claim 1, wherein, when the difference is greater than the predetermined amount, the control means determines the second target diameter so that the difference decreases by a predetermined value or a predetermined rate.

5. 4. The optical device according to claim 1, wherein the control means determines whether the difference is greater than the predetermined amount at predetermined intervals.

6. 4. The optical device according to claim 1, further comprising an operation member that changes the focal length in response to a user operation.

7. 4. The optical device according to claim 1, wherein the control means uses the difference determined at a first timing to determine the second target diameter to be used for control at a second timing that is later than the first timing.

8. The optical device according to any one of claims 1 to 3, characterized in that the control means determines the second target diameter to be used for control at a third timing after the second timing, using the difference determined at a first timing before the second timing.

9. The control means calculating a predicted target diameter corresponding to the first target diameter at a third timing later than the second timing using the first target diameter at a first timing and a second timing later than the first timing; 4. The optical device according to claim 1, wherein the predicted target diameter is used to determine the second target diameter used for control at the third timing.

10. 4. The optical device according to claim 1, wherein the control means controls the aperture diameter based on a focus position.

11. 1. A method for controlling an optical device having an optical system equipped with an aperture stop whose aperture diameter is variable and whose focal length and F-number are variable, comprising: an acquisition step of acquiring the focal length; a control step of controlling the aperture diameter based on the focal length so that the F-number becomes a target F-number, In the control step, When a difference between the aperture diameter and a first target diameter corresponding to the target F-number is smaller than a predetermined amount, the aperture diameter is controlled so as to approach the first target diameter; A control method characterized by changing the first target diameter to a second target diameter when the difference between the opening diameter and the first target diameter is greater than the predetermined amount so that the difference becomes smaller than the predetermined amount.

12. A program causing a computer to execute the method for controlling an optical device according to claim 11.

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