JP2013148614A - Camera system and lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera system in which drive time of a diaphragm device is shortened when taking a still image while shooting a moving image.SOLUTION: A camera system comprises: an optical system which has a diaphragm with a variable aperture amount; imaging means which takes an image of an object through the optical system; a motor which drives the diaphragm device by exciting a plurality of coils; and control means which controls an electric current flowing in the plurality of coils through a micro step drive in a first phase where a rotor position of the motor is not kept when the electric current to the plurality of coils is shut down. The control means controls the electric current flowing in the plurality of coils so that, when a target position of the diaphragm device is changed due to a switchover from moving image shooting to still image shooting, the diaphragm device is driven to a second phase, where the rotor position of the motor is kept when the electric current to the plurality of coils is shut down, at a faster speed than the speed set before the target position is changed.

Description

  The present invention relates to a camera system including an aperture device.

  Conventionally, an aperture device is mounted on a lens device (interchangeable lens) that can be attached to and detached from a camera. Further, the step motor used for driving the diaphragm blades of the diaphragm device is driven using the calculation result of the diaphragm driving amount based on the photometric result. As a stepping motor driving method, in addition to 1-2 phase excitation driving or the like, there is microstep driving in which one step of the stepping motor is controlled more finely by controlling the current flowing in a plurality of coils stepwise. The micro-step drive can drive the aperture device with high accuracy, smoothly and quietly, and is suitable for aperture drive during moving image shooting. In addition, when switching to still image shooting during moving image shooting, in order to drive the diaphragm blades to the open side at a high speed once, after moving the rotor to the stable phase, switch to 1-2 phase excitation drive or the like to perform drive control. There is a way to do it.

  The driving device disclosed in Patent Document 1 controls the aperture during moving image shooting by microstep driving so as to hold the shooting light amount at a predetermined light amount with respect to the field luminance that changes during moving image shooting. It is configured. The imaging device disclosed in Patent Document 2 is configured to perform control suitable for each shooting by changing the excitation method of the step motor between still image shooting and moving image shooting.

JP 2001-69793 A JP 2007-6305 A

  However, if the rotor is located in an unstable phase that is not a stable phase when switching to still image shooting during moving image shooting, the step motor drive method is changed to microstep after moving from the unstable phase to the stable phase at a predetermined speed. It is necessary to switch from driving to 1-2 phase excitation driving. For this reason, with the configuration disclosed in Patent Documents 1 and 2, the diaphragm device cannot be driven in a short time.

  Therefore, the present invention provides a camera system and a lens apparatus in which the driving time of the diaphragm device is shortened when switching to still image shooting during moving image shooting.

  According to another aspect of the present invention, there is provided a camera system including an optical system including an aperture device having a variable aperture, an imaging unit that captures an image of a subject via the optical system, and a plurality of coils that excite the aperture device. A motor for driving, and a control means for controlling the current flowing to the plurality of coils by microstep driving in a first phase in which the rotor position of the motor is not maintained when the current to the plurality of coils is interrupted. When the target position of the diaphragm device is changed due to switching to still image shooting during moving image shooting, the control means holds the rotor position when the current to the plurality of coils is interrupted. Until the second phase is reached, the current flowing through the plurality of coils is controlled so as to drive the diaphragm device at a speed higher than the speed set before the change of the target position. .

  A lens device according to another aspect of the present invention includes an optical system including a diaphragm device having a variable aperture, a motor that drives the diaphragm device by exciting a plurality of coils, and currents to the plurality of coils. Control means for controlling the current flowing to the plurality of coils by microstep driving in a first phase where the rotor position of the motor is not maintained when the motor is shut off. When the target position of the diaphragm device is changed by receiving a signal indicating that switching to shooting has been performed, until the second phase in which the rotor position is maintained when the current to the plurality of coils is interrupted, The current flowing through the plurality of coils is controlled so as to drive the diaphragm device at a speed faster than the speed set before the target position is changed.

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to provide a camera system and a lens apparatus in which the drive time of the diaphragm device is shortened when switching to still image shooting during moving image shooting.

1 is a configuration diagram of a camera system in Embodiment 1. FIG. 1 is a perspective view of a diaphragm device in Embodiment 1. FIG. It is a block diagram of the step motor in Example 1. FIG. It is a drive current waveform figure of the step motor in Example 1. FIG. 6 is a flowchart illustrating photometry / distance measurement processing of the camera system according to the first exemplary embodiment. 3 is a flowchart illustrating communication processing of the imaging lens in Embodiment 1. 3 is a flowchart illustrating aperture driving processing according to the first exemplary embodiment. 3 is a flowchart illustrating aperture driving processing according to the first exemplary embodiment. FIG. 3 is a control pattern diagram of a step motor in Embodiment 1. It is explanatory drawing which shows the state just before the stop of the step motor (rotor position) in Example 2. FIG. 6 is a flowchart illustrating an aperture driving process in Embodiment 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  First, a camera system (imaging device) in Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram of a camera system in the present embodiment. In FIG. 1, reference numeral 100 denotes a camera (imaging device main body), 120 denotes a recording medium, 200 denotes an imaging lens (lens device) that can be attached to and detached from the camera 100, and 400 denotes a strobe that can be attached to and detached from the camera 100. As will be described later, the imaging lens 200 is an optical system including an aperture device with a variable aperture.

  In the camera 100, 1 is a main mirror. The main mirror 1 is obliquely arranged in the photographing optical path in the viewfinder observation state, and is retracted out of the photographing optical path in the photographing state. The main mirror 1 is a half mirror, and when it is obliquely arranged in the photographing optical path, it transmits substantially half of the light beam from the subject to a focus detection unit described later. Reference numeral 2 denotes a focusing plate on which a subject image formed by the imaging lens 200 is projected. 3 is a submirror. The sub mirror 3 and the main mirror 1 are configured so as to be obliquely provided in the photographing optical path in the finder observation state and to be retracted outside the photographing optical path in the photographing state. The sub mirror 3 bends the light beam that has passed through the oblique main mirror 1 and guides it toward the focus detection unit described later. Reference numeral 4 denotes a pentaprism for changing the finder optical path. 5 is an eyepiece. The photographer can observe the photographing screen by observing the focus plate 2 from the window of the eyepiece 5. This state is called an optical finder mode (OVF mode).

  Reference numerals 6 and 7 respectively denote an imaging lens and a photometric sensor for measuring the subject brightness in the viewfinder observation screen. Since the photometric sensor 7 includes a known logarithmic compression circuit, the output of the photometric sensor 7 is logarithmically compressed. 8 is a known phase difference type focus detection unit, and 9 is a shutter (focal plane shutter). Reference numeral 14 denotes an image pickup device (image pickup means) such as a CCD or a CMOS. The imaging element 14 images a subject via the imaging lens 200 (optical system). Reference numeral 16 denotes an A / D converter that converts an analog signal output from the image sensor 14 into a digital signal. A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16, and a D / A converter 26 described later. The timing generation circuit 18 is controlled by a memory control circuit 22 and a system controller 50 described later.

  Reference numeral 20 denotes an image processing circuit. The image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22. The image processing circuit 20 performs predetermined arithmetic processing using the captured image data, and performs TTL AWB (auto white balance) processing based on the obtained arithmetic result. Reference numeral 22 denotes a memory control circuit. The memory control circuit 22 includes an A / D converter 16, a timing generation circuit 18, an image processing circuit 20, an image display memory 24, a D / A converter 26, a memory 30, and a compression / decompression circuit 32 described later. Control. Further, the memory control circuit 22 writes the data of the A / D converter 16 in the image display memory 24 or the memory 30 directly or via the image processing circuit 20.

  Reference numeral 24 denotes an image display memory, 26 denotes a D / A converter, and 28 denotes an image display unit comprising a TFT-LCD or the like. The display image data written in the image display memory 24 is displayed on the image display unit 28 via the D / A converter 26. By sequentially displaying the image data picked up using the image display unit 28 in the state where the main mirror 1 and the sub mirror 3 are raised and the shutter 9 is opened, the electronic finder function can be realized. This state is called an electronic finder mode.

  A memory 30 stores captured still images and moving images. The memory 30 has a storage capacity sufficient to store a predetermined number of still images and a moving image for a predetermined time. The memory 30 is configured to be usable as a work area for the system controller 50. A compression / decompression circuit 32 compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like. The compression / decompression circuit 32 reads an image stored in the memory 30 and performs compression processing or decompression processing. The processed data is written to the memory 30. Reference numeral 40 denotes a shutter control circuit that controls the shutter 9. Reference numeral 41 denotes a mirror control circuit including a motor for driving the main mirror 1 up / down and a drive circuit.

  Reference numeral 50 denotes a system controller that controls the entire camera 100. A memory 52 stores constants, variables, programs, and the like for operating the system controller 50. Reference numeral 54 denotes a display unit such as a liquid crystal display device or a speaker that displays an operation state, a message, and the like using characters, images, sounds, and the like according to execution of a program in the system controller 50. The display unit 54 is installed in a single or a plurality of positions near the operation unit of the camera 100 so as to be easily visible, and is configured by a combination of, for example, an LCD, an LED, and a sounding element. A part of the function of the display unit 54 is displayed at the bottom of the focus plate 2.

  Among the display contents of the display unit 54, the contents to be displayed on the LCD or the like include a single shot / continuous shooting display, a self-timer display, a compression ratio display, a recording pixel number display, a recording number display, a remaining image number display, and a shutter speed display. , Aperture value display, exposure compensation display, flash display. In addition, red-eye reduction display, macro shooting display, buzzer setting display, clock battery level display, battery level display, error display, information display with multiple digits, display / removal status display of recording medium 120, communication I / F operation Display, date / time display, etc. are also displayed on the LED. Further, among the display contents of the display unit 54, there are a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, an exposure correction display, and the like that are displayed below the focus plate 2.

  Reference numeral 56 denotes an electrically erasable / recordable nonvolatile memory, which is configured using, for example, an EEPROM. Reference numerals 60, 62, 64, 66, 68, and 70 are operation members for inputting various operation instructions of the system controller 50. One or a plurality of operation members such as a switch, a dial, a touch panel, a pointing by line-of-sight detection, and a voice recognition device. Consists of Hereinafter, these operation members will be specifically described.

  Reference numeral 60 denotes a mode dial switch. The mode dial switch 60 can switch and set each function mode such as power-off, shooting mode (still image shooting mode, moving image shooting mode), playback mode, deletion mode, PC connection mode, and the like. Reference numeral 62 denotes a shutter switch (SW1). The shutter switch 62 is turned on during the operation of a shutter button (not shown), and instructs to start operations such as AF (autofocus) processing and AE (automatic exposure) processing. Reference numeral 64 denotes a shutter switch (SW2). The shutter switch 64 is turned on when the operation of a shutter button (not shown) is completed, and performs an exposure process in which a signal read from the image sensor 14 is written into the memory 30 via the A / D converter 16 and the memory control circuit 22. . Further, the shutter switch 64 reads the image data from the development processing using the calculation in the image processing circuit 20 and the memory control circuit 22, the memory 30, compresses it in the compression / decompression circuit 32, and writes the image data in the recording medium 120. An instruction to start an operation of a series of processing called recording processing is given.

  Reference numeral 66 denotes a finder mode setting switch. The viewfinder mode setting switch 66 selects the above-described optical viewfinder (OVF) mode and electronic viewfinder (EVF) mode at the time of shooting. When the EVF mode is selected, the main mirror 1 and the sub mirror 3 described above are retracted from the shooting screen, the shutter 9 is opened, and an image captured by the image sensor 14 is always displayed on the image display unit 28. Reference numeral 68 denotes a quick review ON / OFF switch for switching ON / OFF of the quick review. An operation unit 70 includes various buttons and a touch panel. The operation unit 70 includes a menu button, a set button, a macro button, a multi-screen playback page break button, and a single shooting / continuous shooting / self-timer switching button. The operation unit 70 also includes a menu movement + (plus) button, menu movement-(minus) button, reproduction image movement + (plus) button, reproduction image-(minus) button, shooting image quality selection button, exposure correction button, date. / Time setting buttons are also included.

  Reference numeral 80 denotes a power control circuit, which includes a battery detection circuit, a DC-DC converter, a switch circuit that switches blocks to be energized, and the like. The power supply control circuit 80 detects the presence / absence of a battery, the type of battery, and the remaining battery level, controls the DC-DC converter based on the detection result and an instruction from the system controller 50, and supplies a necessary voltage for a necessary period. , And supplied to each unit including the recording medium. The power supply control circuit 80 supplies power to each part of the imaging lens 200 via the communication lines 390 and 391. 82 and 84 are connectors. A power source 86 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiMH battery or a Li battery, an AC adapter, or the like.

  Reference numeral 90 denotes an interface with a recording medium such as a memory card or a hard disk. A connector 92 connects to a recording medium such as a memory card or a hard disk. A recording medium attachment / detachment detection unit 98 detects whether or not the recording medium 120 is attached to the connector 92. As the interface 90 and the connector 92, those compliant with a standard such as a PCMCIA card or a CF (Compact Flash (registered trademark)) card are used. A communication unit 72 has various communication functions such as RS232C, USB, IEEE1394, and wireless communication. Reference numeral 73 denotes a connector for connecting the camera 100 to another device by the communication unit 72, or an antenna in the case of wireless communication. Reference numeral 399 denotes a communication line for performing communication between an imaging lens 200 described later and the system controller 50 on the camera 100 side. Reference numeral 499 denotes a communication line for performing communication between an external strobe 400 described later and the system controller 50 on the camera 100 side. The above are the components of the camera 100.

  Next, the recording medium 120 will be described. The recording medium 120 includes a memory card, a hard disk, and the like. The recording medium 120 includes a recording unit 122 formed of a semiconductor memory, a magnetic disk, or the like, an interface 124 with the camera 100, and a connector 126 that connects to the camera 100.

  Next, the imaging lens 200 (lens device) as an interchangeable lens will be described. Reference numeral 201 denotes a focusing lens that forms a subject image on the image sensor 14 and performs focus adjustment. Reference numeral 202 denotes a focus drive actuator that drives the focusing lens 201 in the optical axis direction to adjust the focus. Reference numeral 211 denotes a focus control circuit that controls the focus drive actuator 202 based on a command from the lens control microcomputer 206 (control means). Reference numeral 203 denotes a subject distance detection circuit including an encoder that detects the subject distance from the position of the imaging lens 200. Reference numeral 204 denotes an aperture (aperture device) that adjusts the amount of light during shooting. Reference numeral 250 denotes an aperture drive actuator. Reference numeral 205 denotes an aperture control circuit that controls the aperture drive actuator 250 based on a command from the lens control microcomputer 206 (control means), and is configured by a known H bridge circuit.

  Reference numeral 207 denotes a zooming lens that adjusts the focal length for zooming. Reference numeral 208 denotes a zoom drive actuator that electrically adjusts the focal length by driving the zooming lens 207 in the optical axis direction. A zoom control circuit 212 controls the zoom drive actuator 208. Reference numeral 206 denotes a lens control microcomputer that communicates with the system controller 50 on the camera 100 side and controls the above-described focus drive and aperture drive. A lens mount 209 is provided so that the imaging lens 200 can be attached to and detached from the camera 100. Reference numeral 210 denotes a connector composed of a serial communication line and a power source, which is electrically connected to the camera 100.

  Next, the external strobe 400 will be described. In the external strobe 400, 401 is a xenon (Xe) tube, and 402 is a reflective shade. Reference numeral 403 denotes a light emission control circuit composed of an IGBT or the like that controls light emission of the xenon tube 401. Reference numeral 404 denotes a charging circuit that generates a voltage of about 300 V to supply power to the xenon tube 401. Reference numeral 405 denotes a power source such as a battery that supplies power to the charging circuit 404. Reference numeral 406 denotes a strobe control microcomputer that controls light emission and charging of the strobe and communicates with the system controller 50 on the camera 100 side. The external strobe 400 is detachably attached to the camera 100 via the hot shoe 410. Further, the camera 100 is electrically connected by a connector 411 including a serial communication line and an X terminal (light emitting terminal). Although the camera 100 and the imaging lens 200 have various other functions, since the relationship with the present invention is small, the description thereof is omitted.

  Next, with reference to FIGS. 2 to 4, the configuration of the diaphragm mechanism in the present embodiment will be described in detail. FIG. 2 is a perspective view of the aperture mechanism. The diaphragm mechanism includes a diaphragm 204 (a diaphragm device) and a diaphragm drive actuator 250. The aperture drive actuator 250 is a step motor (motor), and includes a magnet rotor 251, a stator 252, and a coil 253. With such a configuration, the diaphragm driving actuator 250 drives the diaphragm 204 by exciting a plurality of coils 253.

  The diaphragm 204 includes a cam plate 254, a presser plate 255, a diaphragm opening detection switch 256, and a rotating ring (not shown) and a diaphragm blade that are integrally formed with the light shielding plate 257. The rotating ring receives rotational force from the diaphragm drive actuator 250 and opens and closes the diaphragm blades according to a cam (not shown) formed on the cam plate 254. With such a configuration, the opening amount of the diaphragm 204 is variable. As the aperture opening detection switch 256, for example, a photo interrupter is used. When the light shielding plate 257 passes between the aperture opening detection switch 256, it is turned on / off, and it is detected whether the aperture is open or stopped. The diaphragm 204 is attached to the lens barrel by a tap hole 258 of the presser plate 255, and the cam blade 254 rotates with respect to the presser plate 255 and a rotary ring (not shown), thereby opening and closing the diaphragm blades (not shown). It functions as a diaphragm aperture correction mechanism. Normally, the aperture diameter correcting mechanism is performed in conjunction with a zoom operation by a cam on the lens barrel side (not shown) with a roller attached to the tap hole 259 of the cam plate 254.

  Next, the principle of the step motor will be described with reference to FIG. FIG. 3 is a configuration diagram of a step motor (aperture driving actuator 250). 252a is an A-phase stator, and 253a is an A-phase coil wound around the A-phase stator. 252b is a B-phase stator, and 253b is a B-phase coil wound around the B-phase stator. Reference numeral 251 denotes a magnet rotor (rotor), which is magnetized into an N pole and an S pole as shown in FIG. The respective poles of the A-phase stator 252a and the B-phase stator 252b are switched according to the energization direction to the A-phase coil 253a and the B-phase coil 253b.

  Next, with reference to FIG. 4, the driving method of the step motor will be described. FIG. 4 is a drive current waveform diagram of the A-phase coil and the B-phase coil of the step motor. FIG. 4 (a) shows the waveform for the 1-2 phase excitation drive, and FIG. 4 (b) shows the waveform for the micro step drive. Show. When the step motor (magnet rotor 251 shown in FIG. 3) is driven by the 1-2 phase excitation drive as shown in FIG. 4A, the magnet rotor 251 is brought to an intermediate position between the A phase stator 252a and the B phase stator 252b. Can be stopped. On the other hand, when microstep driving is used as shown in FIG. 4B, the current flowing through the A-phase coil 253a and the B-phase coil 253b is controlled step by step as compared with the case of 1-2-phase excitation driving. The rotational position of the magnet rotor 251 can be finely controlled. For this reason, the diaphragm device can be driven with high precision, smoothness and quietness, and the microstep drive is suitably used for controlling the diaphragm device in moving image shooting.

  Further, the step motor (aperture driving actuator 250) is configured to coincide with the predetermined pattern of the above-described 1-2 phase excitation drive at the aperture open position, and the aperture value manipulated variable by one step in the 1-2 phase excitation drive. 1/8 stage is set. Further, the drive speed of the diaphragm 204 can be controlled by adjusting the change time of the 1-2 phase excitation pattern.

  The open aperture value is determined by the inner diameter dimension (open diameter) of a mechanically fixed disc. The aperture value is determined by taking in and out a plurality of plates called aperture blades by the rotation operation of the step motor. The aperture opening position of the step motor is set to a position where the aperture blade does not protrude beyond the inner diameter of the disc. The difference between the position of the diaphragm blade at the initial position of the step motor and the position where the position of the diaphragm blade becomes the inner diameter of the disk is defined as a run-up section, and the amount is set to 4 steps by the number of steps of 1-2 phase excitation Has been. Although the 1-2 phase excitation drive is used in this embodiment, other drive methods such as a 1 phase excitation drive and a 2 phase excitation drive may be adopted instead.

  Next, the operation of the camera system in the present embodiment will be described. When the shutter switch 62 (SW1) is turned on by operating the shutter button (not shown), the photometry / ranging process is performed to focus the focusing lens 201 on the subject, and the photometric process is performed to obtain the aperture value and the shutter time. To decide. First, with reference to FIG. 5, the photometry / ranging process in the present embodiment will be described in detail. FIG. 5 is a flowchart showing photometry / ranging processing of the camera system.

  First, in step S100, the system controller 50 determines whether or not the EVF mode is set. If the EVF mode is set, the process proceeds to step S101. On the other hand, when the EVF mode is not set, that is, when the optical viewfinder mode (OVF mode) is set, the process proceeds to step S108.

  In step S <b> 101, a charge signal is read from the image sensor 14, and photographed image data is sequentially read into the image processing circuit 20 via the A / D converter 16. Using the sequentially read image data, the image processing circuit 20 is used for TTL (through the lens) type AE (automatic exposure) processing, AF (autofocus) processing, and AWB (auto white balance) processing. Perform a predetermined calculation. In the AE process, the total number of captured pixels is divided into n vertical and m horizontal areas, the average luminance of each area is calculated, and the average luminance value of each of the n × m areas is calculated as necessary. Is multiplied by a weighting factor. As a result, it is possible to perform an optimum calculation for each mode having different center emphasis mode, average mode, and evaluation mode. On the other hand, in the AWB (auto white balance) process, similarly, average values of R, G, and B luminances of n × m areas are obtained, and white balance is set based on the area closest to white. In AF processing, so-called contrast AF processing is performed by detecting high-frequency components of image data in the distance measurement area.

  In step S <b> 102, the system controller 50 determines whether exposure (AE) is appropriate using the calculation result of the image processing circuit 20. If the exposure is not appropriate, the process proceeds to step S103, and AE control is performed using a combination of the aperture control circuit 205 and the electronic shutter of the image sensor 14. Note that the aperture drive command to the imaging lens 200 is performed by known serial communication via the communication line 399 between the camera 100 and the imaging lens 200. At this time, the lens control microcomputer 206 controls the diaphragm control circuit 205 and drives the diaphragm 204 according to the diaphragm driving amount or the diaphragm driving speed instructed from the camera 100. Details of the aperture driving operation in the imaging lens 200 will be described later. On the other hand, when the system controller 50 determines that the exposure (AE) obtained by the AE control is appropriate, the system controller 50 stores the measurement data and the setting parameter in the internal memory or the memory 52 of the system controller 50.

  Subsequently, in step S104, the system controller 50 determines whether or not the white balance (AWB) is appropriate using the calculation result in the image processing circuit 20 and the measurement data obtained by the AE control. If the white balance is not appropriate, the process proceeds to step S105, and the AWB control is performed by adjusting the color processing parameters using the image processing circuit 20. On the other hand, when it is determined that the white balance (AWB) is appropriate, the measurement data and the setting parameters are stored in the internal memory or the memory 52 of the system controller 50.

  In step S106, the system controller 50 performs distance measurement (AF), that is, in-focus determination, using measurement data obtained by the AE control and the AWB control. If it is not in focus, the process proceeds to step S107, where focus drive is commanded to the imaging lens 200 via the communication line 399, and AF control is performed. At this time, the lens control microcomputer 206 controls the focus control circuit 211 in accordance with the focus drive amount or the focus drive speed commanded from the camera 100 to drive the focusing lens 201 in the optical axis direction. In-focus determination is performed using so-called contrast AF in which the focusing lens 201 is driven in the optical axis direction to determine the position where the high-frequency component in the AF area of the image is the highest as the in-focus position. On the other hand, when it is determined that the in-focus state is obtained, the measurement data and the setting parameters are stored in the internal memory or the memory 52 of the system controller 50, and the photometry / ranging processing routine shown in FIG.

  If the EVF mode is not set in step S100, the process proceeds to step S108, where the system controller 50 performs photometry of the photometry sensor 7, and calculates the exposure value according to the result and the preset ISO sensitivity. When the shutter switch 64 (SW2) is pressed after the photometry / ranging process, the state of the photographing mode set by the mode dial switch 60 is determined, and the main mirror 1 and the sub mirror 3 are raised and retracted from the optical axis. Let Further, the communication lens 399 between the camera 100 and the imaging lens 200 is instructed to narrow down the imaging lens 200 (lens control microcomputer 206) to a predetermined aperture value. At this time, the lens control microcomputer 206 controls the diaphragm control circuit 205 and drives the diaphragm 204 in accordance with the diaphragm driving amount or the diaphragm driving speed instructed from the camera 100. The diaphragm driving operation in the imaging lens 200 will be described in detail later.

  Subsequently, in step S110, the system controller 50 determines whether or not the amount of focus deviation detected by the known TTL phase difference type focus detection circuit 8 is within the in-focus range. If it is within the focusing range, the photometry / ranging process shown in FIG. 5 is terminated. On the other hand, if it is out of focus range, the process proceeds to step S111, and the focusing lens 201 is driven and AF control is performed in the same manner as in step S107, and the process returns to step S110 to perform focus determination. When the above process ends, the photometry and distance measurement process ends.

  Next, with reference to FIG. 6, the communication process of the imaging lens 200 will be described. FIG. 6 is a flowchart showing communication processing of the imaging lens 200. First, in step S201, the lens control microcomputer 206 receives a command from the camera 100 via the communication line 399 (serial communication line), and proceeds to step S202. In step S202, the lens control microcomputer 206 performs a process according to the content of the command received in step S201. For example, the command is 1-byte data, and a branch is made based on this data.

  When the command data is “00H” (H means hexadecimal), the process proceeds to step S203, and status transmission processing is performed. If the command data is “01H”, the process advances to step S204 to perform focus lens drive processing. If the command data is “02H”, the process proceeds to step S205 to perform aperture drive processing. In the case of other command data, the process proceeds to step S206, and various data transmission / reception processes are performed. Note that commands from the camera 100 are not limited to these.

  The command “00H” is a command for returning the state (status information) of the imaging lens 200 to the camera 100. This status information is stored in the internal memory of the lens control microcomputer 206. In this embodiment, various types of information such as the state of the diaphragm position detection sensor, the diaphragm operating state, and the AF operating state are set in the internal memory so that they can be determined in bit units. Upon receiving this command data, the lens control microcomputer 206 transmits necessary data to the camera 100 as status information in step S203.

  The command “01H” is a command for instructing focus driving from the camera 100 to the imaging lens 200. When the 2-byte drive data following this command is received, in step S204, the imaging lens 200 drives the focusing lens 201 with the designated drive amount.

  The command “02H” is a command that instructs the imaging lens 200 to drive the aperture from the camera 100. When 1-byte drive data following this command is received, in step S205, the imaging lens 200 operates the diaphragm 204 with the designated drive amount. Details of the aperture driving operation in the imaging lens 200 will be described later.

  As other command data, there is an instruction to transmit / receive various data to / from the camera 100. In step S206, such various data is transmitted and received. The various data are information on the speed at the time of driving the focusing lens, the driving speed of the aperture, and the optics. Information related to optics includes focal length, sensitivity, AF error information, FNo information, and the like.

  FIG. 9 is a control pattern diagram of the step motor, in which the horizontal axis indicates the number of drive steps and the vertical axis indicates the drive speed. FIG. 9 shows two control patterns. The reason why the two control patterns are provided in the step motor is to cope with the noise accompanying the driving of the step motor. The camera 100 according to the present embodiment is configured to be able to select a first shooting mode for taking a still image and a second shooting mode for taking a moving image. In the second shooting mode in which moving image shooting is performed, since the sound is simultaneously recorded, the imaging lens 200 needs to be quiet. Therefore, in the case of the first shooting mode in which still image shooting is performed, the control pattern for the high speed mode is selected with an emphasis on high speed. On the other hand, in the second shooting mode in which moving image shooting is performed, the control pattern for the silent mode is selected with emphasis on the quietness. In the present embodiment, the control pattern for the high speed mode is described as 1-2 phase excitation driving, and the control pattern for the silent mode is described as microstep driving.

  Next, with reference to FIG. 7, a driving process of the diaphragm 204 (a diaphragm device) in the present embodiment will be described. FIG. 7 is a flowchart showing the aperture driving process when an aperture driving instruction and drive data are received. When an aperture drive instruction and drive data are received in step S205 in FIG. 6, in step S301, the lens control microcomputer 206 of the imaging lens 200 determines whether the commanded aperture drive is an open drive or a small aperture drive. Determine. If the aperture drive command is open drive (drive to the open side), the process proceeds to step S302. On the other hand, if the aperture drive command is small aperture drive (drive toward the small aperture side), the process proceeds to step S305.

  If it is determined in step S301 that the drive is to the open side, in step S302, based on the output of the aperture opening detection switch 256, it is detected whether the aperture 204 is in the open position or the aperture position. When the diaphragm 204 is in the open position, the driving of the open side is not necessary, and the processing of this flow is terminated. When the diaphragm 204 is narrowed down, the process proceeds to step S303. Subsequently, in step S303, when the shooting mode of the camera 100 is the first shooting mode in which still image shooting is performed, the control pattern for the high speed mode (1-2 phase excitation drive) is selected. On the other hand, when the shooting mode is the second shooting mode in which moving image shooting is performed, the control pattern (microstep drive) for the silent mode is selected. After one of the shooting modes is set as described above, the process proceeds to step 304.

  In step S304, the received drive amount is set as the drive amount, the drive to the open side is started at the aperture drive speed selected in the photographing mode, and the process ends. Thereafter, in a diaphragm drive process (not shown), the step motor is driven until the received drive quantity becomes equal to the control drive quantity, and the process ends. Further, during the driving to the open side, the output of the aperture opening detection switch 256 is detected, and when it is determined that it is in the open position state, the driving is finished up to the initial position of the step motor regardless of the driving amount.

  If the lens control microcomputer 206 determines in step S301 to drive toward the small aperture side, in step S305, the same processing as in step S303 is performed. That is, when the shooting mode of the camera 100 is the first shooting mode in which still image shooting is performed, the control pattern for the high speed mode (1-2 phase excitation drive) is selected. On the other hand, when the shooting mode is the second shooting mode in which moving image shooting is performed, a control pattern (microstep drive) for the silent mode is selected. After one of the shooting modes is set in this way, the process proceeds to step 306.

  In step S306, driving toward the small aperture side is started at the aperture drive speed received in advance, and the process is terminated. Thereafter, in the aperture driving process (not shown), the stepping motor is driven and the driving is finished until the received driving amount and the control driving amount become equal. If the maximum aperture position that can be driven is reached during the driving toward the small aperture side, the drive is completed up to the initial position of the step motor regardless of the drive amount.

  Next, when the release button (SW2) is pressed while driving in the silent mode during moving image shooting, the shooting mode is switched to still image shooting during moving image shooting. When still image shooting is performed, the opening is driven to the initial position of the step motor regardless of the drive amount, and the small aperture side is driven at the aperture drive speed received in advance. The opening side is preferably driven at a high speed in order to shorten the release time lag.

  Next, with reference to FIG. 8, the diaphragm drive process for shortening the drive time of the diaphragm 204 (a diaphragm device) will be described. FIG. 8 is a flowchart showing the aperture driving process. The flow of FIG. 8 is a control flow for operating the section from the unstable phase to the stable phase of the step motor at a speed higher than the speed set before the target position change. The description about is omitted.

  In step S303, when the shooting mode is the second shooting mode for moving image shooting, and the control pattern for the silent mode (microstep driving) is selected, the process proceeds to step S307. In step S307, the received driving amount is set as the driving amount, and driving to the open side is started at a predetermined aperture driving speed by microstep driving.

  When the release button (SW2) is pressed in step S308, the shooting mode of the camera 100 is switched to still image shooting during moving image shooting. The lens control microcomputer 206 (control means) receives the signal (switching signal) from the system controller 50 and changes the target position of the diaphragm 204 (aperture device). Then, after switching to still image shooting, the process proceeds to step S309. On the other hand, when the release button (SW2) is not pressed, the moving image shooting continues, and the step motor is driven until the received drive amount becomes equal to the control drive amount in the aperture drive process (not shown). This process ends. Further, during the driving to the open side, the output of the aperture opening detection switch 256 is detected, and if it is determined to be in the open position state, the driving is finished up to the initial position of the step motor regardless of the driving amount. .

  In step S309, the lens control microcomputer 206 determines whether the step motor is in the stable phase or the unstable phase. The stable phase is a phase (second phase) in which the rotor position of the step motor is held when currents to the plurality of coils are interrupted. The unstable phase is a phase (first phase) in which the rotor position of the step motor is not maintained when the current to the plurality of coils is interrupted. When the rotor position of the step motor is in the stable phase in step S309, the control pattern is switched to the high-speed mode control pattern (1-2 phase excitation drive), and the process proceeds to step S304. On the other hand, when the rotor position of the step motor is in an unstable phase, the process proceeds to step S310.

  When the rotor position is in the unstable phase, the step motor cannot be driven by 1-2 phase excitation drive. When the rotor position of the step motor is in an unstable phase, the lens control microcomputer 206 controls the current flowing through the plurality of coils by microstep driving. In step S310, the rotor position is moved to a stable phase by microstep driving, and then the motor is driven by switching to 1-2 phase excitation driving. At the time of microstep driving (silent mode control), the imaging lens 200 (lens control microcomputer 206) drives the diaphragm 204 at a speed higher than the previously received diaphragm driving speed (speed set before changing the target position). In this way, the current flowing through the plurality of coils is controlled. This control is performed until the rotor position reaches the stable phase (second phase) from the unstable phase (first phase). When the rotor position moves to the stable phase, the control pattern is switched to the high-speed mode control pattern (1-2-phase excitation drive), and the process proceeds to step S304. In step S304, the lens control microcomputer 206 controls the current flowing through the plurality of coils by the 1-2 phase excitation drive until the rotor position reaches the target position from the stable phase (second phase).

  In step S305, when the shooting mode of the camera 100 is the second shooting mode for moving image shooting, the control pattern for the silent mode (microstep drive) is selected, and the process proceeds to step S311. In step S311, the received driving amount is set as the driving amount, and driving toward the small aperture side is started at the aperture driving speed set according to the photographing mode.

  When the release button (SW2) is pressed in step S311, the shooting mode of the camera 100 is switched to still image shooting during moving image shooting, and the lens control microcomputer 206 changes the target position of the aperture 204 (aperture device). Then, after switching to still image shooting, the process proceeds to step S313. On the other hand, when the release button (SW2) is not pressed, the moving image shooting continues, and the step motor is driven until the received drive amount becomes equal to the control drive amount in the aperture drive process (not shown). This process ends. If the maximum aperture position that can be driven is reached during driving toward the small aperture side, the drive is completed up to the initial position of the step motor regardless of the drive amount.

  In step S313, the lens control microcomputer 206 determines whether the step motor is positioned in the stable phase or the unstable phase. If the rotor position of the step motor is in the stable phase in step S313, the control pattern is switched to the high-speed mode control pattern (1-2 phase excitation drive), and the process proceeds to step S304. On the other hand, when the rotor position of the step motor is in the unstable phase, the process proceeds to step S314.

  When the rotor position is in the unstable phase, the step motor cannot be driven by 1-2 phase excitation drive. For this reason, in step S314, similarly to step S310, the rotor position is moved to the stable phase by the control pattern for the quiet mode (microstep drive), and then the motor is driven by switching to the 1-2 phase excitation drive. During micro-step driving, the lens control microcomputer 206 controls the current flowing through the plurality of coils so as to drive the diaphragm 204 at a speed faster than the speed set before the target position is changed. When the rotor position reaches the stable phase, the control pattern is switched to the high-speed mode control pattern (1-2-phase excitation drive), and the process proceeds to step S304. In step S304, the lens control microcomputer 206 controls the current flowing through the plurality of coils by the 1-2 phase excitation drive until the rotor position reaches the target position from the stable phase (second phase).

  As described above, according to the present embodiment, it is possible to provide a camera system and a lens device in which the driving time of the aperture device is shortened when still image shooting is performed during moving image shooting.

  Next, a camera system and a lens apparatus in Embodiment 2 of the present invention will be described. Since the configuration of the camera system in the present embodiment is the same as that in the first embodiment, description thereof is omitted. The camera system and the lens apparatus according to the present embodiment are different from the first embodiment in that the camera system and the lens apparatus are configured to be able to select a more appropriate stable phase among a plurality of stable phases.

  FIG. 10 is an explanatory diagram showing a state immediately before the stop of the step motor (rotor position) when the release button (SW2) is pressed during driving in the silent mode during moving image shooting. In FIG. 10, the horizontal axis simply shows the aperture value, the left side shows the open side, and the right side shows the small aperture side. Point B and point C are the unstable phase (first phase) of the step motor (rotor) and are the current position. Points A and D are the stable phase (second phase) of the step motor (rotor). The vertical line between the stable phase points A and D indicates the resolution of microstep drive.

  In step S205 in FIG. 6, when the diaphragm drive instruction and drive data are received and driven to the small diaphragm side at the diaphragm drive speed in the silent mode up to the stable phase D point, the step motor is located at the unstable phase B point. Assume that the release button (SW2) is pressed while Since the unstable phase B point is located in the vicinity (closest) to the stable phase A point, the control pattern for the high speed mode as described in the first embodiment is earlier than the time when the unstable phase B point moves to the stable phase D point. It is possible to shift to (1-2 phase excitation drive).

  On the other hand, in step S205 in FIG. 6, when the diaphragm drive instruction and drive data are received and driven to the small diaphragm side at the diaphragm drive speed in the silent mode up to the stable phase D point, the step motor is in the unstable phase C point. Assume that the release button (SW2) has been pressed when it is positioned at. Since the unstable phase C point is located in the vicinity (closest) to the stable phase D point, the control shifts to the high-speed mode control as in the first embodiment before moving to the stable phase A point. be able to.

  Next, with reference to FIG. 11, a diaphragm driving process for shortening the driving time of the diaphragm 204 (a diaphragm device) will be described. FIG. 11 is a flowchart showing the aperture driving process in the present embodiment. The flowchart of FIG. 11 includes a step of selecting a stable phase to be moved when the step motor is positioned in the unstable phase when receiving the aperture drive instruction and the drive data. Note that the description of steps having the same reference numerals as those in FIGS. 7 and 8 is omitted.

  In step S309 in FIG. 11, when the rotor position of the step motor is in an unstable phase, the process proceeds to step S315. In step S315, the lens control microcomputer 206 of the imaging lens 200 selects the stable phase (second phase) closest to the unstable phase (first phase) where the step motor is currently located, and the process proceeds to step S310. . In step S310, the lens control microcomputer 206 flows to the plurality of coils so as to drive the diaphragm 204 at a speed higher than the speed set before the change of the target position until the stable phase selected in step S315 is reached. The current is controlled (microstep drive).

  In step S316, if the rotor position of the step motor is in an unstable phase, the process proceeds to step S316. In step S316, the lens control microcomputer 206 selects the stable phase (second phase) closest to the unstable phase (first phase) in which the step motor is currently located, and proceeds to step S314. In step S314, the lens control microcomputer 206 flows to the plurality of coils so as to drive the diaphragm 204 at a speed higher than the speed set before the change of the target position until the stable phase selected in step S316 is reached. The current is controlled (microstep drive).

  Thus, the second phase in the present embodiment is the phase closest to the first phase. For this reason, according to the present embodiment, it is possible to provide a camera system and a lens device in which the drive time of the aperture device is further shortened when still image shooting is performed during moving image shooting.

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

DESCRIPTION OF SYMBOLS 100 ... Camera 200 ... Imaging lens 204 ... Aperture 50 ... System controller 206 ... Lens control microcomputer

Claims (6)

An optical system having a diaphragm device with a variable aperture,
Imaging means for imaging a subject via the optical system;
A motor that excites a plurality of coils to drive the diaphragm device;
Control means for controlling the current flowing to the plurality of coils by microstep driving in a first phase in which the rotor position of the motor is not maintained when the current to the plurality of coils is interrupted;
When the target position of the diaphragm device is changed by switching to still image shooting during moving image shooting, the control means holds the rotor position when the current to the plurality of coils is interrupted. Until the phase of 2 is reached, the current flowing through the plurality of coils is controlled so as to drive the diaphragm device at a speed faster than the speed set before the change of the target position. .   The camera system according to claim 1, wherein the second phase is a phase closest to the first phase.   The control means controls the current flowing through the plurality of coils by 1-2 phase excitation drive until the rotor position reaches the target position from the second phase. The camera system described in. An optical system having a diaphragm device with a variable aperture,
A motor that excites a plurality of coils to drive the diaphragm device;
Control means for controlling the current flowing to the plurality of coils by microstep driving in a first phase in which the rotor position of the motor is not maintained when the current to the plurality of coils is interrupted;
When the target position of the diaphragm device is changed by receiving a signal indicating that switching to still image shooting is performed during moving image shooting, the control means is configured to stop the rotor position when current to the plurality of coils is interrupted The current flowing through the plurality of coils is controlled so as to drive the diaphragm device at a speed faster than the speed set before the change of the target position until the second phase is maintained. Lens device.   The lens apparatus according to claim 4, wherein the second phase is a phase closest to the first phase.   The said control means controls the electric current which flows into the said several coil by 1-2 phase excitation drive until the said rotor position reaches | attains the said target position from the said 2nd phase. The lens device according to 1.