Optical instrument and method for controlling the same

Abstract

To provide an optical instrument that can smoothly control a diaphragm value for the operation of a diaphragm ring, and controls the diaphragm value with good accuracy.SOLUTION: An optical instrument 100 has: a diaphragm unit 102 that has variable diaphragm value; an operating member 105 that can be operated by a user; instruction means 120 that outputs a diaphragm instruction value according to the operation of the operating member; and control means 120 that generates a target diaphragm value from the diaphragm instruction value, and controls the drive of the diaphragm unit based on the target diaphragm value. The control means performs first processing of generating a target diaphragm value of first resolution from the diaphragm instruction value, and second processing of generating a target diaphragm value of second resolution finer than the first resolution from the diaphragm instruction value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical device capable of driving an aperture in response to the operation of an operating member. [Background technology]

[0002] An optical device equipped with an operating member (aperture ring) for specifying an aperture setting value is disclosed in, for example, Patent Document 1. In such optical devices, a user can specify an aperture value by operating the aperture ring to align the position of an index provided on the aperture ring with an index for each aperture value provided near the aperture ring. There are also optical devices in which the rotational position (or amount of rotation) of an electronic ring-type aperture ring is detected by a sensor, and a motor mounted on an electromagnetic aperture is driven according to the detected rotational position, thereby controlling the aperture value (aperture diameter). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-53271 A Summary of the Invention [Problem to be solved by the invention]

[0004] When using an electronic aperture ring, the detection resolution of the rotational position of the aperture ring and the drive resolution of the electromagnetic aperture are increased (fine), which makes it possible to smoothly respond to the operation of the aperture ring in controlling the aperture value and aperture diameter of the electromagnetic aperture. As a result, it becomes possible to capture videos with smooth changes in brightness, especially when capturing videos.

[0005] However, if the detection resolution of the rotational position of the aperture ring is fine, the electromagnetic aperture may be driven in response to a minute change in the rotational position of the aperture ring, which may cause an error in the aperture value. As a result, the accuracy of the aperture value may decrease, particularly in still image capture, and a still image with the desired brightness may not be obtained.

[0006] The present invention provides an optical device capable of controlling the aperture value with high accuracy and smoothly in response to the operation of an operation member. [Means for solving the problem]

[0007] An optical device according to one aspect of the present invention includes an aperture unit with a variable aperture value, an operating member operable by a user, an instruction means for outputting an aperture instruction value according to the operation of the operating member, and a control means for generating a target aperture value from the aperture instruction value and controlling the drive of the aperture unit based on the target aperture value. The control means performs a first process for generating a target aperture value with a first resolution from the aperture instruction value, and a second process for generating a target aperture value with a second resolution finer than the first resolution from the aperture instruction value.

[0008] A control method according to another aspect of the present invention is applied to an optical device having an aperture unit with a variable aperture value and an operating member that can be operated by a user. The control method includes a step of outputting an aperture instruction value according to the operation of the operating member, a step of generating a target aperture value from the aperture instruction value, and a step of generating the target aperture value from the aperture instruction value and controlling the drive of the aperture unit based on the target aperture value. The step of generating the target aperture value includes a first process of generating a target aperture value with a first resolution from the aperture instruction value, and a second process of generating a target aperture value with a second resolution finer than the first resolution from the aperture instruction value. Note that a program for causing a computer to execute processes according to the above control method also constitutes another aspect of the present invention. Effect of the Invention

[0009] According to the present invention, in an optical device having an aperture unit, it is possible to control the aperture value with good precision and smoothly in response to the operation of an operation member. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a block diagram showing a configuration of an interchangeable lens and a camera body according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing the appearance of an aperture ring and its surroundings in the interchangeable lens of the first embodiment. [Diagram 3] FIG. 4 is a diagram showing the structure of stored data of the position of the aperture ring in the first embodiment. [Figure 4] 4 is a flowchart showing an aperture control process in the first embodiment. [Diagram 5] 4 is a flowchart showing a diaphragm index value determination process in the first embodiment. [Figure 6] 11 is a flowchart showing a diaphragm index value determination process in the second embodiment. [Figure 7] 11 is a flowchart showing a diaphragm index value determination process in the third embodiment. [Figure 8] 13 is a flowchart showing a diaphragm index value determination process in the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] 1 shows the configuration of a camera system including a lens unit 100 as an optical device (lens apparatus) used in common in Examples 1 to 4 described below, and a camera body 200 (imaging device) to which the lens unit 100 is detachably and communicably attached. Note that each example is based on a lens-interchangeable camera system, but the two rounding resolutions in the aperture control process described below may be applied to a lens-integrated camera as the optical device.

[0013] The lens unit 100 has an imaging optical system. The imaging optical system includes, in order from the subject side (the left side of the figure), a field lens 101, an aperture unit 102, and a focus lens 103. The aperture unit 102 has a variable aperture diameter (in other words, aperture position) to adjust the amount of light passing through the imaging optical system. The aperture position is a position that realizes a predetermined aperture index value (F value or T value). In the aperture unit 102, the aperture blades 102a and 102b are driven in the opening and closing directions by the driving force of a stepping motor 109, thereby changing the aperture diameter. In the following description, the driving of the aperture blades 102a and 102b is referred to as driving the aperture unit 102.

[0014] The focus lens 103 adjusts the focus of the imaging optical system by moving in the optical axis direction (the direction of the arrow in the figure). The focus lens 103 is held by a lens frame and a guide shaft (not shown) so as to be movable in the optical axis direction, and is driven in the optical axis direction by receiving a driving force from a stepping motor 111.

[0015] The lens unit 100 has a lens microcomputer (hereinafter referred to as lens microcomputer) 120 as a lens control means. The lens microcomputer 120 controls the driving of the focus lens 103 and the aperture unit 102 in response to user operation of a focus operation ring 104, an aperture operation ring 105, and the like, which serve as operation members provided on the lens unit 100. The stepping motors 111 and 109 are driven via drive circuits 110 and 108, respectively, in response to commands from the lens microcomputer 120.

[0016] The lens microcomputer 120 also performs control in response to various lens control commands transmitted from the camera body 200 (a camera microcomputer 206, described later).

[0017] The lens microcomputer 120 grasps the aperture position, which indicates the position of the aperture blades 102a and 102b in the opening / closing direction, by integrating the driving amount of the stepping motor 109. The lens microcomputer 120 outputs an aperture control signal to the driving circuit 108 based on the aperture position. The driving circuit 108 drives the stepping motor 109 in response to the aperture control signal.

[0018] Here, even if the aperture blades 102a and 102b of the aperture unit 102 are driven by the drive amount according to the design value, an error occurs in the aperture diameter due to error factors such as component precision and assembly error. In this embodiment, when the stepping motor 109 is driven in microsteps, it is designed so that the aperture diameter changes by 1 / 16 step for each drive of one step based on a 1-2 phase drive wave. In the following explanation, when the drive amount of the stepping motor 109 is explained in terms of the number of steps, the number of steps is calculated based on the 1-2 phase drive wave unless otherwise specified.

[0019] If the above error factors exist, the amount of change in the aperture diameter is not exactly 1 / 16 stops even if the stepping motor 109 is driven by one step, and the error often occurs in various ways depending on the positions at which the aperture blades 102a and 102b are driven. In this embodiment, in order to deal with such errors, a correction value for correcting the drive amount of the stepping motor 109 is stored in the storage unit 122 for each aperture index value (Fno). The aperture index value is set in 1 / 32 step increments (1 / 32 step units) from the open aperture to the minimum aperture, with INDEX0 being the open aperture. The correction amount as the adjustment amount is stored in the storage unit 122 as a value in units equivalent to 1 / 256 steps. By actually projecting observation light onto the image plane through the imaging optical system and evaluating the amount of light reaching the image plane while changing the aperture diameter from the open aperture to the minimum aperture, it is possible to calculate the correction amount when changing the aperture diameter by 1 / 32 steps. As a result, the aperture unit 102 of this embodiment can form a highly accurate aperture diameter at each aperture index value in 1 / 32 step increments from the maximum aperture.

[0020] The focus operation ring 104 is a rotatable operating member for performing a manual focus (MF) operation for inputting an instruction for the user to move the focus lens 103 to an arbitrary position. The direction and amount of rotation of the focus operation ring 104 are detected by a focus rotation detection unit 123. The focus rotation detection unit 123 is composed of a photointerrupter and a slit light shielding plate that rotates between a light emitting unit and a light receiving unit of the photointerrupter in response to the rotation of the focus operation ring 104. The photointerrupter outputs a pulse signal when the light transmitting unit and the light shielding unit of the slit light shielding plate are alternately positioned between the light emitting unit and the light receiving unit. The pulse signal is input to a lens microcomputer 120. The lens microcomputer 120 detects the amount of rotation of the focus operation ring 104 by counting the pulse signal.

[0021] The focus rotation detector 123 is configured by combining two photointerrupters arranged at a predetermined interval from each other and one slit light shielding plate. The lens microcomputer 120 can determine the rotation direction of the focus operation ring 104 by identifying which of the output pulse waveforms from the two photointerrupters is the leading one.

[0022] Furthermore, by measuring the time from an edge where the level of the output signal of one photointerrupter switches to the next edge of the output signal of the other photointerrupter, the rotation speed of the focus operation ring 104 can be detected (calculated). However, if the two photointerrupters are not spaced apart according to the design value, the dimensional error appears as a time error between the edges, making it impossible to detect an accurate rotation speed. Therefore, there is no such problem between the edges of the output signal of one photointerrupter, and in this embodiment, the lens microcomputer 120 detects the rotation speed of the focus operation ring 104 using the time interval at which these edges appear.

[0023] Lens microcomputer 120 controls the driving of focus lens 103 in response to MF operation information (information on rotation direction, rotation amount, and rotation speed) detected through focus rotation detection unit 123 and a focus drive command transmitted from camera microcomputer 206, which will be described later. The drive control of focus lens 103 is performed by driving stepping motor 111 via drive circuit 110.

[0024] In this embodiment, the focus rotation detector 123 is configured using a photointerrupter, but may be configured using a capacitance sensor, a magnetic sensor, or the like.

[0025] The aperture operation ring 105 is a rotatable operating member that performs aperture operation to input an instruction for the user to set the aperture unit 102 to an arbitrary aperture index value. The aperture operation ring 105 can only be rotated within a movable range between two operating ends. The rotation direction, rotation amount, and rotation position (operation position) of the aperture operation ring 105 are detected by an aperture ring rotation detection unit 106 serving as a detection means. The aperture ring rotation detection unit 106 is composed of a magnetic sensor, and detects the aperture ring position as an absolute rotation position within the movable range of the aperture operation ring 105.

[0026] 2 shows the appearance of the aperture operation ring 105 and its surroundings on the lens unit 100. On the surface of the housing of the lens unit 100 near the aperture operation ring 105, Fno is marked as an aperture index value. In this embodiment, aperture index values ​​are marked in order of increasing Fno from the maximum aperture of F2.8 to the minimum aperture of F16, with index lines as guides marked at every 1 / 3 stop between the aperture index values. The two operating ends of the aperture operation ring 105 are set to the maximum aperture (F2.8) and the minimum aperture (F16).

[0027] In addition, an index line is marked at one location on the outer periphery of the aperture operation ring 105. The user can specify the aperture diameter of the aperture unit 102 by rotating the aperture operation ring 105 so as to align the index line marked on the aperture operation ring 105 with the aperture index value on the housing side of the lens unit 100 as a guide.

[0028] The lens unit 100 of this embodiment is provided with an aperture ring changeover switch (not shown). The aperture ring changeover switch is operated by the user to instruct switching between manual aperture mode and auto aperture mode. The manual aperture mode is a mode in which the aperture unit 102 is driven to a position corresponding to an aperture index value specified by operation of the aperture operation ring 105. The auto aperture mode is a mode in which an aperture index value can be specified by control from the camera body 200. In the auto aperture mode, an aperture index value determined mainly by automatic exposure (AE) control or an aperture index value specified by the user via a menu in the camera body 200 is specified. In the following, unless otherwise specified, aperture control in the manual aperture mode will be described.

[0029] The lens unit 100 stores aperture ring detection value information for associating the relationship between the aperture ring position (detection value) detected by the aperture ring rotation detection unit 106 and the position of each aperture index value on the surface of the housing in the storage unit 122. By using this aperture ring detection value information, it is possible to calculate the corresponding aperture index value from the rotation position (aperture ring position) detected by the aperture ring rotation detection unit 106 when the aperture operation ring 105 is operated.

[0030] 3 shows the data structure of aperture ring detection value information. In the figure, (a) is the main body of the aperture ring detection value information stored in the storage unit 122, with the upper row showing INDEX 0 to 15 and the lower row showing the aperture ring positions (detection values) corresponding to each of INDEX 0 to 15. In the figure, (b) shows AV values ​​(upper row) and Fno (lower row) in 1 / 256 stop units associated with each of INDEX 0 to 15 in (a). In the following explanation, AV values ​​in 1 / 256 stop units will be referred to as 1 / 256 stop AV values.

[0031] As shown in this diagram, the aperture ring detection value information is made up of 16 pieces of data, from INDEX 0 to INDEX 15, and indicates the detection values ​​by the aperture ring rotation detection unit 106 for each aperture index value in 1 / 3 stop increments from the maximum aperture of F2.8 to the minimum aperture of F16. These detection values ​​are those that were actually operated to the position of each aperture index value when the lens unit 100 was manufactured, and the detection values ​​for each aperture index value at that time were stored in the memory unit 122.

[0032] For example, a case where 501 is detected as the detection value in the aperture ring rotation detection unit 106 will be described. When the detection value is 501, referring to FIG. 3(a), the aperture index value corresponds to an aperture value between F3.5 and F4. Since the detection value at F3.5 is 470 and the detection value at F4 is 701, the detection value of 231 corresponds to 1 / 3 stops. Therefore, the aperture position corresponding to the detection value 501 is a position narrowed down by 31 in detection values ​​from F3.5. At this time, since 1 / 3 stops of the 1 / 256-stop AV value is equivalent to 0x60, the position narrowed down by 31 / 231 is a position narrowed down by 0xC as the 1 / 256-stop AV value. In this way, the aperture position corresponding to the detection value 501 is 0x3AD, which is a position narrowed down by 0xD from 0x3A0 in the 1 / 256-stop AV value from the ratio calculation, that is, around F3.575.

[0033] The flowchart in Fig. 4 shows basic aperture control processing executed by the lens microcomputer 120. The lens microcomputer 120 executes this processing in accordance with a program that is started at regular intervals (1 msec, for example). S stands for step.

[0034] The current process starts 1 msec after the previous process. First, in S401, the lens microcomputer 120 acquires a detection value from the aperture ring rotation detection unit 106 as the current rotation position of the aperture operation ring 105 (aperture ring position).

[0035] Next, in S402, the lens microcomputer 120 as an instruction unit performs a process of converting the detection value acquired from the aperture ring rotation detection unit 106 into an aperture index value (aperture instruction value: hereinafter, referred to as a current aperture index value).

[0036] Next, in S403, the lens microcomputer 120 determines (generates) a target aperture index value as a target aperture value of the aperture unit 102 from the current aperture index value. This process will be described later.

[0037] Next, in S404, the lens microcomputer 120 calculates the drive amount of the stepping motor 109 for driving the aperture unit 102 from the aperture value corresponding to the current aperture index value to the aperture value corresponding to the target aperture index value determined in S404 (i.e., the target aperture drive position of the aperture unit 102).

[0038] 5 shows details of the processing of S404. First, in S501, the lens microcomputer 120 calculates the stop-down step number by subtracting the maximum aperture index value as a design value from the target aperture index value determined in S403.

[0039] Next, in S502, the lens microcomputer 120 calculates the designed aperture drive position.

[0040] Next, in S503, the lens microcomputer 120 acquires a drive correction amount. As described above, in this embodiment, the storage unit 122 holds a correction value in units of 1 / 256 stops for correcting the drive amount of the aperture unit 102 (stepping motor 109) in units of 1 / 32 stops from the maximum aperture. The lens microcomputer 120 determines the drive correction amount by normalizing the aperture stop number calculated in S501 in units of 1 / 32 stops (obtaining the number of units when calculating how many units to stop down in 1 / 32 stops). The lens microcomputer 120 then adds the drive correction amount determined in this way to the aperture stop number calculated in S501 to calculate the corrected drive amount of the stepping motor 109.

[0041] In S405 of FIG. 4, the lens microcomputer 120 drives the stepping motor 109 by the corrected drive amount via the aperture drive circuit 108 so as to drive the aperture unit 102 to the target aperture drive position calculated in S404.

[0042] By repeatedly executing the above process at 1 msec intervals, it becomes possible to control the aperture diameter of the aperture unit 102 so as to follow the operation of the aperture operation ring 105 at 1 msec intervals. At this time, by designing a program so that the current aperture diameter control can be started even if the aperture diameter control of the aperture unit 102 started in the previous process has not been completed, it is possible to realize follow-up control of the aperture unit 102 while updating the target aperture drive position sequentially at 1 msec intervals.

[0043] Camera body 200 has an imaging element 201 such as a CCD sensor or a CMOS sensor that captures (photoelectrically converts) a subject image formed by lens unit 100. Camera body 200 also has a signal processing unit 202, a recording processing unit 203, a camera microcomputer (hereinafter referred to as camera microcomputer) 206 as camera control means, and a display unit 204.

[0044] The image sensor 201 photoelectrically converts the subject image and outputs an electrical signal (analog signal). This analog signal is converted into a digital signal by an A / D conversion circuit (not shown), and the digital signal is input to the signal processor 202. The signal processor 202 performs various signal processes on the input digital signal to generate a focus signal representing the focus state of the imaging optical system (subject image), generate a luminance signal representing the exposure state, and generate a video signal. The video signal generated by the signal processor 202 is sent to the recording processor 203, and still image data and video data obtained from the video signal are recorded on a recording medium (not shown). At this time, the digital signal as imaging information input to the signal processor 202 is also used as a photometry evaluation value, and control is performed so that the exposure is appropriate by automatic exposure control. Specifically, a balance is calculated between the current aperture index value acquired by inquiring of the lens microcomputer 120, the shutter speed setting held in the camera microcomputer 206, and the sensor sensitivity setting so that the photometry evaluation value is appropriate exposure. In this embodiment, the shutter speed setting and the sensor sensitivity setting can be adjusted with a resolution of 1 / 128 steps.

[0045] The camera body 200 and the lens unit 100 are mechanically and electrically connected by a mount 300, which is a coupling portion. The lens unit 100 receives power from the camera body 200 via a power terminal portion provided on the mount 300. The camera microcomputer 206 and the lens microcomputer 120 communicate with each other via a communication terminal portion provided on the mount 300. The camera microcomputer 206 transmits an aperture drive command and a focus drive command to the lens microcomputer 120.

[0046] The operation unit 205 is an input interface provided on the camera body 200, and includes an image capture instruction switch, a camera setting switch, etc. The camera microcomputer 206 controls the camera body 200 in response to an input from the operation unit 205. EXAMPLES

[0047] Next, a description will be given of Example 1. In this example and Examples 2 to 4 described below, an aperture control process (aperture control method) will be described in which the lens microcomputer 120 can select the rounding resolution used to calculate (generate) a target aperture index value from a current aperture index value according to the operation of the aperture operation ring 105. The aperture control process in each example is characterized by the process executed in S403 in the flowchart of FIG.

[0048] In S402 described above, the detection value from the aperture ring rotation detection unit 106 is converted into a current aperture index value in 1 / 256-stop AV value (1 / 256-stop resolution). In this embodiment, this current aperture index value (aperture indication value) is rounded with a specific rounding resolution to an AV value, which is converted into a target aperture index value (target aperture value) to be actually used. In this embodiment, the specific rounding resolution can be specified from the camera body 200 (camera microcomputer 206).

[0049] The rounding resolution is a value that indicates the amount of change in the target aperture value relative to the amount of change in the current aperture index value in 1 / 256 stops. A rounding resolution in 1 / 256 stops, which will be described later, means that when the amount of change in the current aperture index value reaches 1 / 256 stops, the target aperture value also changes by 1 / 256 stops. Furthermore, a rounding resolution in 1 / 32 stops, which will be described later, means that when the amount of change in the current aperture index value reaches 1 / 256 stops x 8, the target aperture value changes by 1 / 32 stops.

[0050] The camera microcomputer 206 specifies the rounding resolution to the lens microcomputer 120 by command communication via the mount 300. The camera microcomputer 206 can specify the rounding resolution to the lens microcomputer 120 at any time. At this time, by specifying a rounding resolution (first resolution) in 1 / 32-step units corresponding to the unit step (correction resolution) of the correction value for the aperture unit 102, the aperture unit 102 can be controlled to a target aperture index value with high accuracy and reproducibility of the aperture diameter. At this time, since the automatic exposure control controls both the shutter time setting and the sensor sensitivity setting with a resolution of 1 / 128 steps, the occurrence of residual errors in the automatic exposure control can also be reduced by setting the target aperture index value with a rounding resolution in 1 / 32-step units, which is coarser (lower) than that. The process of generating a target aperture index value with a rounding resolution in 1 / 32-step units is the first process.

[0051] Separately from this, the camera microcomputer 206 can set the rounding resolution (second resolution) of 1 / 256 steps explained in Fig. 3 to the lens microcomputer 120. This allows the aperture diameter of the aperture unit 102 to change very smoothly in response to the operation of the aperture operation ring 105 compared to the case where a rounding resolution of 1 / 32 steps is used. The process of generating a target aperture index value with a rounding resolution of 1 / 256 steps is the second process.

[0052] In this manner, in this embodiment, the rounding resolution can be selected between the first resolution and the second resolution in accordance with a specification from the camera body 200. The selectable rounding resolution and the correction resolution of the aperture unit 102 may be held in a pre-programmed state in the camera microcomputer 206 as design values, or may be notified from the lens microcomputer 120 to the camera microcomputer 206 by command communication.

[0053] According to this embodiment, when it is preferable to increase the accuracy of the automatic exposure control, such as when capturing a still image, a precision-priority rounding resolution (first resolution) equivalent to the correction resolution of the aperture unit 102 is set, thereby enabling highly accurate automatic exposure control with reduced residuals. On the other hand, when priority is given to a smooth tracking change of the aperture value in response to the operation of the aperture operation ring 105 rather than the accuracy of the aperture value (aperture diameter), such as when capturing a moving image, a tracking-priority rounding resolution (second resolution) finer than the correction resolution is set. This makes it possible to capture a natural moving image in which sudden changes in brightness are suppressed. EXAMPLES

[0054] Next, a description will be given of embodiment 2. In this embodiment, the rounding resolution according to the aperture control mode set in the camera body 200 is selected.

[0055] In this embodiment, the lens unit 100 has two aperture control methods for controlling the aperture unit 102 in response to the operation of the aperture operation ring 105. The camera microcomputer 206 can specify one of the two aperture control methods, a first method or a second method, to the lens microcomputer 120 at any time by command communication. The lens microcomputer 120 performs a first process when the first method is specified, and performs a second process when the second method is specified.

[0056] The flowchart in Fig. 6 shows the processing executed in S403 in Fig. 4 in this embodiment. First, in S601, the lens microcomputer 120 checks the aperture control method specified by the camera microcomputer 206. If the specified aperture control method is the first method, the process proceeds to S602, where the rounding resolution is set to a precision-priority rounding resolution (first resolution) equivalent to the correction resolution (in 1 / 32 step units) of the aperture unit 102.

[0057] On the other hand, if the specified aperture control method is the second method, the lens microcomputer 120 proceeds to S603 and sets the rounding resolution to a tracking-priority rounding resolution (second resolution) in 1 / 256 step units that is finer than the precision-priority resolution.

[0058] Next, in S604, the lens microcomputer 120 calculates the target aperture index value using the rounding resolution set in S602 or S603.

[0059] According to this embodiment, when the first method is specified as the aperture control method in the camera body 200, a precision-priority rounding resolution equivalent to the correction resolution of the aperture unit 102 is set, thereby enabling highly accurate automatic exposure control with reduced residuals. On the other hand, when the second method is specified, a tracking-priority rounding resolution finer than the correction resolution is set. This makes it possible to capture natural moving images in which sudden changes in brightness are suppressed. EXAMPLES

[0060] Next, a description will be given of embodiment 3. In this embodiment, the rounding resolution according to the imaging mode set in the camera body 200 is selected.

[0061] In this embodiment, the lens microcomputer 120 can obtain the imaging mode currently set in the camera body 200 from the camera microcomputer 206 by command communication.

[0062] The flowchart in Fig. 7 shows the processing executed in S403 in Fig. 4 in this embodiment. First, in S701, the lens microcomputer 120 checks the imaging mode currently set in the camera body 200. If the imaging mode set is a still image imaging mode, the process proceeds to S702, where the lens microcomputer 120 sets the rounding resolution to a precision-priority rounding resolution (first resolution) equivalent to the correction resolution (in 1 / 32 step units) of the aperture unit 102 at its own discretion.

[0063] On the other hand, if the imaging mode is the video imaging mode, the lens microcomputer 120 proceeds to S703 and sets the rounding resolution to a tracking-priority rounding resolution (second resolution) in 1 / 256 step units that is finer than the precision-priority resolution at the lens microcomputer 120's own discretion.

[0064] Next, in S704, the lens microcomputer 120 calculates the target aperture index value using the rounding resolution set in S702 or S703.

[0065] According to this embodiment, when the still image capture mode is set in the camera body 200, a precision-priority rounding resolution equivalent to the correction resolution of the aperture unit 102 is set, thereby enabling highly accurate automatic exposure control with reduced residuals. On the other hand, when the video capture mode is set, a tracking-priority rounding resolution finer than the correction resolution is set. This makes it possible to capture natural video with suppressed sudden changes in brightness. EXAMPLES

[0066] Next, a fourth embodiment will be described. In this embodiment, a rounding resolution is selected according to the presence or absence of a click function for the rotation operation of the aperture operation ring 105. The click mechanism (click means) 150 shown in parentheses in FIG. 1 generates a clicking sensation mechanically or electrically for each predetermined amount of operation of the aperture operation ring 105. The click mechanism 150 of this embodiment is configured to be able to switch the presence or absence (enable and disable) of the click function for the rotation operation of the aperture operation ring 105. For example, the presence or absence of the click function can be switched by sliding the aperture operation ring 105 in the optical axis direction relative to the housing of the lens unit 100. The lens unit 100 has a sensor that detects the slide position of the aperture operation ring 105 in the optical axis direction, i.e., the presence or absence of the click function.

[0067] Furthermore, the lens microcomputer 120 is capable of acquiring the rounding resolution (in 1 / 2 step units, 1 / 3 step units, etc.) for calculating the aperture index value from the camera microcomputer 206 through command communication.

[0068] The flowchart in Fig. 8 shows the process executed in S403 in Fig. 4 in this embodiment. First, in S801, the lens microcomputer 120 checks whether or not the aperture operation ring 105 has a click function. If the click mechanism is present, the process proceeds to S802, where the rounding resolution is set to a precision-priority rounding resolution (first resolution). The precision-priority rounding resolution at this time is set to 1 / 2 step or 1 / 3 step units, etc., obtained from the camera microcomputer 206.

[0069] On the other hand, if the click function is not present, the lens microcomputer 120 proceeds to S803 and sets the rounding resolution to a tracking-priority rounding resolution (second resolution) in units of 1 / 256 steps that is finer than the precision-priority resolution.

[0070] Next, in S804, the lens microcomputer 120 calculates the target aperture index value using the rounding resolution set in S702 or S703.

[0071] According to this embodiment, when the lens unit 100 has a click function for the aperture operation ring 105, a precision-priority rounding resolution equivalent to the correction resolution of the aperture unit 102 is set, enabling highly accurate automatic exposure control with reduced residuals. On the other hand, when there is no click function and the video shooting mode is set, a tracking-priority rounding resolution finer than the correction resolution is set. This makes it possible to capture natural videos with suppressed sudden changes in brightness.

[0072] In each embodiment, Fno is used as the aperture index value, but an effective aperture value Tno taking into account the light transmittance of the imaging optical system may be used as the aperture index value.

[0073] The above embodiment includes the following configurations.

[0074] (Configuration 1) an aperture unit having a variable aperture value; An operation member that can be operated by a user; an instruction unit that outputs an aperture instruction value in response to the operation of the operation member; a control means for generating a target aperture value from the aperture instruction value and controlling the driving of the aperture unit based on the target aperture value; the control means performs a first process of generating the target aperture value with a first resolution from the aperture instruction value, and a second process of generating the target aperture value with a second resolution finer than the first resolution from the aperture instruction value. (Configuration 2) The optical device described in configuration 1, characterized in that the control means drives the aperture unit with a drive amount obtained using the target aperture value of the first resolution generated in the first processing and a correction value set in units corresponding to the second resolution. (Configuration 3) the optical device is detachably attached to an imaging device, 2. The optical device according to configuration 1, wherein the control means performs the first or second processing corresponding to one of the first and second resolutions designated by the imaging device. (Configuration 4) the optical device is detachably attached to an imaging device, 2. The optical device according to configuration 1, wherein the control means performs one of the first and second processes in accordance with an aperture control method specified by the imaging device. (Configuration 5) the optical device is detachably attached to an imaging device, 2. The optical device according to configuration 1, wherein the control means performs one of the first and second processes in accordance with an imaging mode set in the imaging device. (Configuration 6) a click means for generating a clicking sensation each time the operating member is operated by a predetermined amount, the click means is capable of switching between generation and non-generation of the click sensation, 2. The optical device according to configuration 1, wherein the control means performs one of the first and second processes depending on whether the click means is present or not. (Configuration 7) 7. The optical device according to any one of configurations 1 to 6, wherein the first resolution is a 1 / 32 step resolution, and the second resolution is a 1 / 256 step resolution. (Other Examples) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0075] The embodiments described above are merely representative examples, and various modifications and alterations are possible for each embodiment when implementing the present invention. [Explanation of symbols]

[0076] 100 Lens unit 102 Aperture unit 105 Aperture control ring 106 Aperture ring rotation detector 120 Lens microcomputer

Claims

1. an aperture unit with a variable aperture value; an operation member that can set the aperture value in response to an operation by a user; an instruction means for outputting an aperture instruction value in response to the operation of the operation member; a control means for generating a target aperture value from the aperture instruction value and controlling the driving of the aperture unit based on the target aperture value; the control means performs a first process of generating the target aperture value with a first resolution from the aperture instruction value, and a second process of generating the target aperture value with a second resolution finer than the first resolution from the aperture instruction value.

2. The optical device according to claim 1, wherein the control means drives the aperture unit with a drive amount obtained using the target aperture value of the first resolution generated in the first processing and a correction value set in units corresponding to the second resolution.

3. the optical device is detachably attached to the imaging device, 2. The optical apparatus according to claim 1, wherein the control means performs the first or second processing corresponding to one of the first and second resolutions designated by the imaging device.

4. the optical device is detachably attached to the imaging device, 2. The optical apparatus according to claim 1, wherein the control means performs one of the first and second processes corresponding to an aperture control method designated by the image pickup device.

5. the optical device is detachably attached to the imaging device, 2. The optical apparatus according to claim 1, wherein the control means performs one of the first and second processes according to an imaging mode set in the imaging device.

6. a click means for generating a clicking sensation each time the operating member is operated by a predetermined amount, the click means is capable of switching between generating and not generating the click feeling, 2. The optical device according to claim 1, wherein the control means performs one of the first and second processes depending on whether the click means is present or not.

7. 1. A method for controlling an optical device having an aperture unit with a variable aperture value and an operation member that can set the aperture value in response to an operation by a user, comprising: outputting an aperture indication value according to operation of the operation member; generating a target aperture value from the aperture instruction value; generating a target aperture value from the aperture instruction value and controlling the drive of the aperture unit based on the target aperture value, a control method characterized in that, in the step of generating the target aperture value, a first process is performed to generate the target aperture value with a first resolution from the aperture instruction value, and a second process is performed to generate the target aperture value with a second resolution finer than the first resolution from the aperture instruction value.

8. A program causing a computer to execute a process according to the control method of claim 7.

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