JP2009088825A - Camera system, and camera main body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a period of time till exposing an imaging element again after photographing cannot be shortened. <P>SOLUTION: A camera system is provided with: an imaging optical system L for forming an optical image of an object; a lens shutter 8 arranged in the optical path of the imaging optical system L; an imaging part 35 for converting the optical image into an image signal to acquire the image of the object; and a focal plane shutter 5 which is arranged more on the object side from the imaging part, and the camera system drives the focal plane shutter to perform photographing in a state that the lens shutter is opened, and reads electric charge of the imaging part in a state that the lens shutter is closed and performs opening operation of the focal plane shutter in parallel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a camera system and a camera body.

  In recent years, digital cameras that can convert an optical image of a subject into an electrical image signal and output it have become widespread. A digital camera has an image sensor that converts an optical image of a subject into an electrical image signal. There are two types of exposure time (hereinafter also referred to as shutter speed) of the image sensor at the time of photographing, that is, an electric shutter and a mechanical shutter. As mechanical means, a lens shutter and a focal plane shutter are known. The lens shutter and the focal plane shutter are arranged in the optical path. Then, at the time of photographing, these are driven so that the optical path is closed and the light to the image sensor is shielded, the optical path is opened to expose the image sensor, and the optical path is closed again to shield the light to the image sensor. .

In general, the focal plane shutter can be controlled to have a shorter exposure time than the lens shutter. A digital camera having a focal plane shutter is generally known (for example, Patent Document 1).
JP 2000-152057 A

  The image pickup device exposed at the time of shooting accumulates electric charges. It is necessary to block the light to the image sensor until the charge is read out. In a conventional digital camera, the focal plane shutter is in a state where the optical path is closed after shooting. Therefore, in order to expose the image sensor again after shooting, it is necessary to wait for the charge plane to be read from the image sensor while the focal plane shutter is closed, and then to open the focal plane shutter. is there.

  The present invention has been made in view of this point, and an object thereof is to provide a camera system and a camera body that can shorten the time until the image sensor is exposed again after shooting.

  The object of the present invention can be achieved by the following constitution.

  The camera system includes an imaging optical system that forms an optical image of a subject, a lens shutter disposed in an optical path of the imaging optical system, and an imaging unit that converts the optical image into an image signal and acquires the image of the subject And a focal plane shutter provided closer to the subject than the imaging unit. Then, shooting is performed by driving the focal plane shutter with the lens shutter opened, and reading the charge of the imaging unit and opening operation of the focal plane shutter in parallel with the lens shutter closed. Do.

  The camera body includes a mount capable of mounting a lens barrel having an imaging optical system that forms an optical image of a subject, an imaging unit that converts the optical image into an image signal and acquires the subject image, and the imaging unit A focal plane shutter provided closer to the subject, and a determination unit that determines whether or not the lens barrel mounted on the mount has a lens shutter. When the determination unit determines that the lens barrel has the lens shutter, the focal plane shutter is driven with the lens shutter opened to perform shooting, and the lens shutter is closed. Thus, the charge reading of the imaging unit and the opening operation of the focal plane shutter are performed in parallel.

  In a camera system including a camera body and a lens barrel that can be attached to the mount, the lens barrel has information on whether the lens barrel has the lens shutter, and the camera body includes: Information on whether or not the lens barrel has the lens shutter is acquired from the lens barrel.

  The determination unit of the camera body determines whether the lens barrel has the lens shutter based on information on whether the lens barrel has the lens shutter.

  Further, the focal plane shutter has a front curtain and a rear curtain, and operates the front curtain so that the optical path is opened from a state where the optical path is closed by the front curtain, and in parallel with the operation of the front curtain. Shutter driving is performed to operate the rear curtain so as to close the optical path.

  In addition, the readout of the charge of the imaging unit is started with the focal plane shutter closed, and the readout of the charge of the imaging unit and the closing operation of the lens shutter are performed in parallel with the focal plane shutter closed. Do.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the camera system and camera main body which can shorten time until it exposes an image pick-up element again after imaging | photography.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure and each embodiment, the same numerals are given to the same composition, and a part of explanation is omitted.

(Embodiment 1)
As a first embodiment, a camera body having a detachable lens barrel, and a camera system including the camera body and the lens barrel will be described.

<1: Configuration of camera system 1>
FIG. 1 is a block diagram showing a schematic configuration of the camera system according to the present embodiment. As shown in FIG. 1, the camera system 1 is an interchangeable lens digital camera system. The camera system 1 includes a camera body 3 having the main functions of the camera system 1 and an interchangeable lens barrel 2 (hereinafter also referred to as an interchangeable lens 2) that is detachably attached to the camera body 3. Yes. The interchangeable lens 2 has a lens mount 71 at a position closest to the camera body. The camera body 3 has a body mount 4 on the front surface. The lens mount 71 and the body mount 4 are mechanically and electrically connected. The interchangeable lens 2 is connected to the camera body 3 by connecting the lens mount 71 and the body mount 4.

(1.1: Camera body 3)
The camera body 3 mainly includes an imaging unit 35 that captures an image of a subject, a contrast value detection unit 38, a body-side shutter unit 37, and a body microcomputer 10 as a body control unit that controls the operation of each unit such as the imaging unit 35. The body mount 4 includes an image display unit 36 that displays a captured image and various information, and a shutter operation unit 30.

  The imaging unit 35 mainly includes an imaging element 11 such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor that performs photoelectric conversion, and an imaging element drive control unit 12 that controls the operation of the imaging element 11. is doing. The image sensor 11 is driven and controlled by a timing signal generated by the image sensor drive controller 12. The imaging unit 35 converts the optical image of the subject received on the imaging surface into an image signal, and acquires the subject image.

  The contrast value detection unit 38 calculates a contrast evaluation value based on the image signal generated by the image sensor 11 and transmits the evaluation value to the body microcomputer 10. The contrast value detection unit 38 and the body microcomputer 10 perform autofocus control (hereinafter also referred to as contrast AF) by a contrast detection method. The camera system 1 can realize a focus operation with high accuracy by using contrast AF.

  The main body side shutter unit 37 includes a focal plane shutter 5 that adjusts the exposure state of the image sensor 11 and a shutter control unit 31 that controls driving of the focal plane shutter 5 based on a control signal from the body microcomputer 10. Yes. The focal plane shutter 5 has a rear curtain 6 and a front curtain 7. The focal plane shutter 5 is provided closer to the subject than the imaging unit 35. The focal plane shutter 5 operates the front curtain 7 so that the optical path is opened from the state where the optical path is closed by the front curtain 7, and operates the rear curtain 6 so as to close the optical path in parallel with the operation of the front curtain 7. The shutter is driven. Details will be described later.

  The body microcomputer 10 is a control device that controls the center of the camera body 3 and controls various sequences. Specifically, the body microcomputer 10 is equipped with a CPU, ROM, and RAM, and the body microcomputer 10 can realize various functions by reading a program stored in the ROM into the CPU. For example, the body microcomputer 10 acquires information essential for controlling the camera system 1 such as a function of detecting that the interchangeable lens 2 is attached to the camera body 3 or focal length information from the interchangeable lens 2. It has a function to do. The body microcomputer 10 functions as a determination unit that determines whether the interchangeable lens 2 mounted on the body mount 4 has the lens shutter 8.

  The body microcomputer 10 controls the entire camera system such as the image sensor 11 in response to an instruction from an operation member such as the shutter operation unit 30. The body microcomputer 10 transmits a vertical synchronization signal to the timing generator. In parallel with this, the body microcomputer 10 generates an exposure synchronization signal based on the vertical synchronization signal.

  The body microcomputer 10 can communicate with the lens microcomputer 40 of the interchangeable lens 2 via the body mount 4 and the lens mount 71. The body microcomputer 10 periodically transmits the generated exposure synchronization signal to the lens microcomputer 40 via the body mount 4 and the lens mount 71. The body microcomputer 10 also transmits other signals to the lens microcomputer 40. The body microcomputer 10 receives a signal from the lens microcomputer 40 via the body mount 4 and the lens mount 71.

  The body mount 4 can be mechanically and electrically connected to the lens mount 71 of the interchangeable lens 2. The body mount 4 has a body mount contact (not shown). The body mount contact is electrically connected to a lens mount contact (not shown) of the lens mount 71 and transmits signals between the lens microcomputer 40 and the body microcomputer 10. The body mount 4 and the lens mount 71 are part of a signal communication line between the interchangeable lens 2 and the camera body 3. Specifically, the body mount 4 and the lens mount 71 are part of a signal communication line between the body microcomputer 10 and the lens microcomputer 40. Further, the body mount 4 supplies the interchangeable lens 2 with the power received from the power supply unit (not shown) of the camera body 3 via the lens mount 71.

  The shutter operation unit 30 is, for example, a release button that is operated by a photographer or the like at the time of shooting. When the shutter operation unit 30 is operated, a timing signal is output to the body microcomputer 10. The shutter operation unit 30 is a two-stage press switch that can detect a half-press operation and a full-press operation. When a photographer or the like performs a half-press operation, the first switch S1 is turned on and a first timing signal is output. . Then, the camera system 1 starts photometry processing, focusing operation, and the like. Subsequently, when the photographer or the like performs a full press operation, the second switch S2 is turned on, and a second timing signal is output. The shutter control unit 31 operates the focal plane shutter 5 according to the control signal output from the body microcomputer 10 to expose the image sensor 11 for a predetermined time. Details will be described later.

  FIG. 2 is a block diagram showing a schematic configuration of the camera body according to the present embodiment. As shown in FIG. 2, the camera body 3 further includes an analog signal processing unit 13, an A / D conversion unit 14, a digital signal processing unit 15, a buffer memory 16, an image compression unit 17, an image reading / recording unit 18, an image A recording control unit 19 and a power switch 25 are provided. The image signal output from the image sensor 11 is sequentially sent from the analog signal processing unit 13 to the A / D conversion unit 14, the digital signal processing unit 15, the buffer memory 16, and the image compression unit 17 for processing.

  The analog signal processing unit 13 performs analog signal processing such as gamma processing on the image signal output from the image sensor 11. The A / D conversion unit 14 converts the analog signal output from the analog signal processing unit 15 into a digital signal, and outputs a digital image signal. The digital signal processing unit 15 performs digital signal processing such as noise removal and edge enhancement on the digital image signal converted into the digital signal by the A / D conversion unit 14 and outputs the digital signal processed image signal. . The buffer memory 16 is a RAM (Random Access Memory) and temporarily stores an image signal subjected to signal processing. The image-processed image signal stored in the buffer memory 16 is sequentially sent from the image compression unit 17 to the image reading / recording unit 18 for processing. The signal-processed image signal stored in the buffer memory 16 is read by an instruction from the image recording control unit 19 and transmitted to the image compression unit 17. The image signal data transmitted to the image compression unit 17 is compressed into an image signal in accordance with an instruction from the image recording control unit 19. By this compression processing, the image signal becomes a compressed image signal having a data size smaller than that of the original data. As such a compression method, for example, a JPEG (Joint Photographic Experts Group) method is used. Thereafter, the compressed image signal is recorded in the image reading / recording unit 18 by the image recording control unit 19.

  The image reading / recording unit 18 records the compressed image signal and the predetermined information to be recorded in association with each other based on a command from the image recording control unit 19, and is removable from, for example, the internal memory and / or the camera body 3. Removable memory. The predetermined information to be recorded together with the compressed image signal includes the date and time when the image was shot, focal length information, shutter speed information, aperture value information, and shooting mode information. It is a format similar to the Exif (registered trademark) format and the Exif (registered trademark) format.

  The image display unit 36 includes a display unit 20 and an image display control unit 21. The display unit 20 is a liquid crystal monitor, for example, and displays an image signal recorded in the image reading / recording unit 18 or the buffer memory 16 as a visible image based on a command from the image display control unit 21. Here, the display form of the display unit 20 includes a display form in which only an image signal is displayed as a visible image, and a display form in which the image signal and information at the time of shooting are displayed as a visible image.

(1.2: Interchangeable lens)
Returning to FIG. 1, the interchangeable lens 2 includes an imaging optical system L for connecting an optical image of a subject to the imaging element 11 in the camera system 1. The imaging optical system L includes a focus lens L1 that moves in a direction parallel to the optical axis X to perform focusing. The interchangeable lens 2 further includes a focus lens drive control unit 41, a lens shutter 8, a lens shutter control unit 42 that controls the operation of the lens shutter 8, a diaphragm 43, and a lens control unit that controls the operation of the interchangeable lens 2. A lens microcomputer 40 and a lens mount 71.

  The focus lens drive control unit 41 drives and controls the focus lens L1 that mainly adjusts the focus.

  The lens shutter 8 has a plurality of shutter blades. When the shutter blades gather on the optical axis X, the lens shutter 8 closes the optical path and blocks light from the subject (hereinafter also referred to as subject light) from the interchangeable lens 2 to the camera body 3. Further, when each shutter blade is separated from the optical axis X, an optical path is opened, and subject light is guided from the interchangeable lens 2 to the camera body 3. The lens shutter 8 moves each shutter blade only to the vicinity of the optical axis X. In general, the opening / closing operation of the shutter blades of the lens shutter 8 is faster than the opening / closing operation of the front curtain 7 and the rear curtain 6 of the focal plane shutter 5. However, the shortest exposure time of the lens shutter 8 is longer than the shortest exposure time of the focal plane shutter 5 that controls the exposure time at the interval between the front curtain 7 and the rear curtain 6.

  The diaphragm 43 has a plurality of diaphragm blades. As each diaphragm blade approaches the optical axis X, the aperture diameter of the optical path is reduced. Further, when each diaphragm blade is separated from the optical axis X, the aperture diameter of the optical path is increased. The size of the aperture diameter of the diaphragm 43 is called an aperture value. The size of the light beam of the subject light passing through the interchangeable lens 2 is determined by the size of the aperture diameter of the aperture 43, in other words, the size of the aperture value. The brightness of the optical image of the subject and the so-called depth of field are determined by the size of the luminous flux of the subject light.

  The lens microcomputer 40 is a control device that controls the center of the interchangeable lens 2, and is connected to each part mounted on the interchangeable lens 2. Specifically, the lens microcomputer 40 is equipped with a CPU, a ROM, and a RAM, and various functions can be realized by reading a program stored in the ROM into the CPU. Moreover, it is electrically connected to the body microcomputer 10 via an electrical contact (not shown) provided on the lens mount 71, so that information can be transmitted and received with each other. Various information (hereinafter also referred to as lens information) relating to the interchangeable lens 2 is stored in a memory unit (not shown) in the lens microcomputer 40. The lens information includes information regarding whether or not the interchangeable lens 2 has the lens shutter 8.

<2: Operation of camera system 1>
Next, various operations of the camera system 1 will be described.

(2.1: Operation at startup)
When the power switch 25 is turned on, power is supplied to each part of the camera body 3 from a power source (not shown). When the interchangeable lens 2 is mounted on the body mount 4, the body mount 4 supplies the power received from the power supply unit (not shown) of the camera body 3 to each part of the interchangeable lens 2 via the lens mount 71. When the interchangeable lens 2 is mounted on the body mount 4, the body microcomputer 10 communicates with the lens microcomputer 40 and acquires lens information from the lens microcomputer 40.

(2.2: Contrast AF)
The camera system 1 has a so-called live view mode in which shooting is performed while checking the subject displayed on the display unit 20. The camera system 1 can perform contrast AF. Contrast AF is suitable for shooting in live view mode. This is because in the live view mode, the image signal to be displayed on the imaging unit 20 is generated by the imaging element 11, and the image signal can be used for contrast AF in parallel.

  When performing the live view mode, the body microcomputer 10 determines whether or not the interchangeable lens 2 is compatible with contrast AF. Specifically, the body microcomputer 10 requests contrast AF data from the lens microcomputer 40. The contrast AF data is data necessary for the contrast type autofocus operation, and includes, for example, a focus drive speed, a focus shift amount, an image magnification, and contrast AF availability information. The body microcomputer 10 communicates with the lens microcomputer 40, acquires contrast AF data, and determines whether the interchangeable lens 2 is compatible with contrast AF based on this data. When it is determined that the interchangeable lens 2 is compatible with contrast AF, the camera system 1 performs contrast AF in the live view mode.

  The body microcomputer 10 periodically generates a vertical synchronization signal. In parallel with this, the body microcomputer 10 generates an exposure synchronization signal based on the vertical synchronization signal. The body microcomputer 10 generates an exposure synchronization signal based on the exposure start timing and the exposure end timing of the image sensor 11 with reference to the vertical synchronization signal. The body microcomputer 10 grasps the exposure start timing and the exposure end timing of the image sensor 11. The body microcomputer 10 outputs a vertical synchronization signal to a timing generator (not shown), and outputs an exposure synchronization signal to the lens microcomputer 40. The lens microcomputer 40 acquires position information of the focus lens L1 in the optical axis X direction in synchronization with the exposure synchronization signal.

  The image sensor drive control unit 12 periodically generates a read signal of the image sensor 11 and an electronic shutter drive signal based on the vertical synchronization signal. The image sensor drive control unit 12 drives the image sensor 11 based on the readout signal and the electronic shutter drive signal. That is, the image sensor 11 reads out pixel data generated by a large number of photoelectric conversion elements (not shown) in the image sensor 11 to a vertical transfer unit (not shown) according to the read signal. Pixel data in a predetermined area of the image sensor 11 is output as an image signal. The image signal is displayed on the display unit 20 after being processed by the analog signal processing unit 13 or the like. The display image of the display unit 20 is updated according to the read signal. Accordingly, the moving image of the subject is displayed on the display unit 20. This control mode is called live view mode. According to the live view mode, the user can determine a composition for capturing a still image or a moving image while viewing the display unit 20. Note that since the image signal is processed from the imaging by the imaging device 11 to the display on the display unit 20, the moving image of the subject is displayed with a slight delay.

  In the above state, the body microcomputer 10 monitors whether or not the shutter operation unit 30 is half-pressed. When the shutter operation unit 30 is half-pressed, the body microcomputer 10 transmits an autofocus start command to the lens microcomputer 40. The autofocus start command is a command indicating that contrast AF is started. In response to this, the lens microcomputer 40 issues a drive command to the focus lens drive control unit 41. The focus lens drive control unit 41 controls the drive of the focus lens L1. The lens microcomputer 40 acquires position information (hereinafter, also referred to as lens position information) of the focus lens L1 in the optical axis X direction, and transmits it to the body microcomputer 10. Further, the body microcomputer 10 issues a command to the contrast value detection unit 38. The contrast value detection unit 38 calculates an evaluation value of contrast for autofocus operation (hereinafter also referred to as AF evaluation value) based on the image signal generated by the image sensor 11. Specifically, a method of obtaining an AF evaluation value by obtaining a luminance signal from an image signal generated by the image sensor 11 and integrating high-frequency components in the screen of the luminance signal is known. The calculated AF evaluation value is stored in a DRAM (not shown) in a state associated with the exposure synchronization signal. The lens position information acquired from the lens microcomputer 40 is also associated with the exposure synchronization signal. Therefore, the body microcomputer 10 can store the AF evaluation value in association with the lens position information.

  Next, the body microcomputer 10 obtains a contrast peak based on the AF evaluation value stored in the DRAM and the lens position information. Specifically, the lens position of the focus lens L1 at which the AF evaluation value becomes the maximum value is extracted as the focal point. As this lens driving method, a hill-climbing method is generally known. Then, the focus lens L1 is driven to the lens position where the AF evaluation value becomes the maximum value, and the focusing operation is finished.

(2.3: Operation of focal plane shutter)
FIG. 3 shows the operating state of the focal plane shutter 5. The focal plane shutter 5 includes a rear curtain 6, a front curtain 7, and a shutter holding frame 9. The rear curtain 6 is urged downward in the drawing by a rear curtain urging means (not shown). The front curtain 7 is also urged in the same direction as the urging direction of the rear curtain 6. The shutter holding frame 9 has an opening.

  (A) shows the open state of the focal plane shutter 5. In the open state (a), the shutter drive motor (not shown) is driven in a direction opposite to the urging direction, and the rear curtain 6 is retracted to the upper side of the paper from the opening, and is then retracted. The rear curtain 6 is held. The open state (a) is a state in which the front curtain 7 is retracted to the lower side of the drawing than the opening by the urging means. When the focal plane shutter 5 is in the open state (a), the optical path to the image sensor 11 is opened. The above contrast AF and live view modes are performed when the focal plane shutter 5 is in the open state. In the following, the operation of driving the rear curtain 6 in the direction opposite to the urging direction to retract the rear curtain 6 to the upper side of the drawing than the opening is also referred to as rear curtain opening charge.

  When the shutter operation unit 30 is fully pressed, the focal plane shutter 5 shifts from the open state (a) to the exposure preparation state (b). Specifically, from the open state (a), the front curtain 7 is driven in a direction opposite to the urging direction by a shutter drive motor (not shown), and the front curtain 7 shields the opening, and the exposure preparation state ( Go to b). Thereafter, exposure is started. In the exposure preparation state (b), the front curtain 7 is held in a state where the opening is shielded. In the following, the operation of driving the front curtain 7 in the direction opposite to the urging direction to shield the opening with the rear curtain is also referred to as a front curtain closing charge.

  When the exposure preparation is completed, the front curtain 7 is operated so that the optical path is opened from the state where the optical path is closed by the front curtain 7, and the rear curtain 6 is operated so as to close the optical path in parallel with the operation of the front curtain 7. The shutter is driven. (C) shows a state during exposure by shutter driving. The holding of the front curtain 7 is released from the exposure preparation state. Then, the front curtain 7 moves to the lower side of the page so as to open the opening by the urging means. After the holding of the front curtain 7 is released, the holding of the rear curtain 6 is released. Then, the rear curtain 6 moves to the lower side of the page so as to shield the opening by the urging means. During exposure, the front curtain 7 and the rear curtain 6 move while keeping the gap s between the front curtain 7 and the rear curtain 6 constant. Light passing through the gap s between the front curtain 7 and the rear curtain 6 enters the image sensor 11. An opening having a gap s between the front curtain 7 and the rear curtain 6 moves downward from the top of the paper, thereby exposing the entire image sensor 11. The exposure time of the image sensor 11 can be controlled by appropriately adjusting the gap s. The gap s is controlled by controlling the time from the release of the holding of the front curtain 7 to the release of the rear curtain 6. Specifically, the time from the release of the holding of the front curtain 7 to the release of the rear curtain 6 is set as a desired exposure time.

  In the exposure completion state (d), the front curtain 7 is retracted below the opening. Further, the rear curtain 6 shields the opening. The image sensor 11 is shielded from light by the rear curtain 6. When contrast AF is performed again or when live view is performed, the rear curtain opening charge is performed from the exposure completion state (d), and the opening state (a) is thereafter performed.

  The focal plane shutter 5 can realize a very fast shutter speed by reducing the gap s between the front curtain 7 and the rear curtain 6 during exposure. However, since the front curtain 7 and the rear curtain 6 need to move over the entire opening, it takes time for the rear curtain opening charge and the front curtain closing charge.

(2.4: Operation during shooting using an interchangeable lens without a lens shutter)
First, the operation at the time of shooting of the camera system when an interchangeable lens not equipped with a lens shutter is attached to the imaging lens will be described. When an interchangeable lens (not shown) that does not include the lens shutter 8 is attached to the camera body 3, the body microcomputer 10 communicates with the lens microcomputer 40 via an electrical contact (not shown) between the body mount 4 and the lens mount 71. If the lens barrel has information that the lens barrel does not have a lens shutter, the body microcomputer 10 acquires the information and determines that the interchangeable lens does not have the lens shutter 8. If the lens barrel does not have information regarding whether or not the lens barrel has a lens shutter, the body microcomputer 10 determines that the information cannot be acquired from the lens microcomputer 40 and determines that the interchangeable lens does not have a lens shutter. To do. When the body microcomputer 10 determines that the interchangeable lens is not equipped with the lens shutter 8, the operation at the time of shooting is as follows.

  FIG. 4 shows a sequence diagram of the photographing operation when an interchangeable lens not equipped with a lens shutter is attached. The horizontal axis is time. A solid line indicates the operation of the front curtain 7. The vertical position of the solid line indicates the position of the end of the front curtain 7 on the opening side. An upper side of the solid line is opened, and a lower side of the solid line is shielded by the front curtain 7. A broken line indicates the operation of the trailing curtain 6. The position in the vertical direction of the broken line indicates the position of the end of the rear curtain 6 on the opening side. The lower side of the broken line is open, and the upper side of the broken line is shielded by the front curtain 7. That is, when the broken line is above the solid line, a state is shown in which the gap between the broken line and the solid line is open.

  The operation will be described from the state where the shutter operation unit 30 is fully pressed after the shutter operation unit 30 is pressed halfway and the contrast AF is completed. At this time, the focal plane shutter 5 is in the open state (a) due to contrast AF. When the shutter operation unit 30 is fully pressed by the photographer, the body microcomputer 10 instructs the shutter control unit 31 to close the front curtain 7 of the focal plane shutter 5. After the closing charge of the front curtain 7 is completed (b), the focal plane shutter 5 operates and is driven in the order of the front curtain 7 and the rear curtain 6 to expose the image sensor 11 (c). The image sensor 11 discharges the already accumulated charges before the start of exposure. After the exposure of the image sensor 11 is completed, the focal plane shutter 5 is in a closed state (d). In this state (d), the image sensor drive control unit 12 reads an image signal from the image sensor 11. The closed state (d) of the focal plane shutter 5 is maintained until the reading of the image signal from the image sensor 11 is completed.

  After the image signal has been read, the body microcomputer 10 instructs the shutter control unit 31 to open the rear curtain 6 of the focal plane shutter 5. After the opening of the rear curtain 6 is completed, the body microcomputer 10 waits for completion of a series of processes after the exposure, and then confirms that the state of the shutter operation unit 30 is not pushed in and ends the photographing sequence. .

  The time required for reading the image data from the image sensor 11 is 160 msec as an example, and the time required for the front curtain opening charge and the rear curtain closing charge of the focal plane shutter 6 is 90 msec. If exposure is performed during readout of image data, noise will be generated in the image data and image quality will be degraded. Therefore, after the completion of readout of the image signal, the rear curtain must be charged. Therefore, it takes 250 msec (160 msec + 90 msec) from the completion of exposure until the next time the focal plane shutter 5 is opened (a) and the image sensor 11 can be exposed. Therefore, when it is desired to continuously perform imaging and it is desired to perform contrast AF before the next imaging, it takes time. Also, it takes time to perform live view after shooting.

(2.5: Operation during shooting using an interchangeable lens with a lens shutter)
Next, the operation at the time of shooting of the camera system 1 using the interchangeable lens 2 equipped with the lens shutter 8 will be described.

  When the body microcomputer 10 determines that the interchangeable lens 2 is equipped with the lens shutter 8, the operation at the time of shooting is as follows.

  FIG. 5 shows operating states (A) to (F) of the lens shutter 8 and the focal plane shutter 5 at the time of photographing by the camera system of the present invention. In the drawing, (a) to (d) show the same state as the operation state of the focal plane shutter 5 shown in FIG.

  In the state shown in (A), both the lens shutter 8 and the focal plane shutter 5 are in the open state, and the image sensor 11 is exposed. In the open state (a), contrast AF is possible. After the contrast AF is completed by half-pressing the shutter operation unit 30 and the shutter operation unit 30 is fully pressed by the photographer, the body microcomputer 10 causes the shutter control unit 31 to close the front curtain 7 of the focal plane shutter 5. Is instructed. When the closing charge of the front curtain 7 is completed, the focal plane shutter 5 enters the exposure preparation state (b). At this time, the lens shutter 8 remains open (B). Thereafter, the focal plane shutter 5 operates to expose the image sensor 11 (c). At the time of exposure, the lens shutter 8 maintains an open state (C). After the exposure is completed (FIG. 5d), a command is transmitted from the body microcomputer 10 to the lens microcomputer 40, and an operation to close the lens shutter 8 is instructed from the lens microcomputer 40 to the lens shutter control unit 42. The lens shutter control unit 42 performs an operation of closing the lens shutter 8. At that time, the focal plane shutter 5 maintains the closed state (d). The lens shutter 8 is closed, and the lens shutter 8 and the focal plane shutter 5 are both closed (E). Thereafter, a command is transmitted from the body microcomputer 10 to the shutter control unit 31, an operation for opening the rear curtain 6 of the focal plane shutter 5 is instructed, and the opening of the rear curtain 6 is completed (a). At this time, the lens shutter 8 is kept closed (F).

  FIG. 6 shows a sequence diagram of the photographing operation when an interchangeable lens equipped with a lens shutter is attached. The horizontal axis is time. The upper solid line is a sequence diagram of the lens shutter 8. The lower solid line and broken line are sequence diagrams of the focal plane shutter 5.

In the sequence diagram of the lens shutter 8, the vertical position of the solid line indicates the position of the end portion of the lens shutter 8 on the opening side of the shutter blade. The solid line is at the upper position when the lens shutter 8 is in the open state, and the solid line is at the lower position when the shutter blades are gathered on the optical axis and the lens shutter 8 is in the closed state.

  In the sequence diagram of the focal plane shutter 5, the solid line indicates the operation of the front curtain 7. The vertical position of the solid line indicates the position of the end of the front curtain 7 on the opening side. An upper side of the solid line is opened, and a lower side of the solid line is shielded by the front curtain 7. A broken line indicates the operation of the trailing curtain 6. The position in the vertical direction of the broken line indicates the position of the end of the rear curtain 6 on the opening side. The lower side of the broken line is open, and the upper side of the broken line is shielded by the front curtain 7. That is, when the broken line is above the solid line, the focal plane shutter 5 shows a state where the gap between the broken line and the solid line is open.

  The operation will be described from the state where the shutter operation unit 30 is fully pressed after the shutter operation unit 30 is pressed halfway and the contrast AF is completed. At this time, because of contrast AF, the lens shutter 8 and the focal plane shutter 5 are in the open state (A). When the shutter operation unit 30 is fully pressed by the photographer, the body microcomputer 10 instructs the shutter control unit 31 to close the front curtain 7 of the focal plane shutter 5. After the closing charge of the front curtain 7 is completed with the lens shutter 8 opened (B), the focal plane shutter 5 operates with the lens shutter 8 opened, and the front curtain 7 and the rear curtain 6 are driven in this order. Then, the image sensor 11 is exposed (C) to perform photographing. The image sensor 11 discharges the already accumulated charges before the start of exposure. After the exposure of the image sensor 11 is completed, the focal plane shutter 5 is in the closed state (D) with the lens shutter 8 being opened. In this state (D), the image sensor drive control unit 12 starts reading an image signal from the image sensor 11. Specifically, the image sensor drive control unit 12 starts reading image signals from the image sensor 11 simultaneously with the completion of exposure. Further, after the exposure is completed (D), a command is transmitted from the body microcomputer 10 to the lens microcomputer 40, and an operation to close the lens shutter 8 is instructed from the lens microcomputer 40 to the lens shutter control unit 42. While the focal plane shutter 5 is closed (d), the reading of the image signal from the image sensor 11 and the operation of closing the lens shutter 8 are performed in parallel. After the operation of closing the lens shutter 8 is completed (E), a command is transmitted from the body microcomputer 10 to the shutter control unit 31 to instruct an operation of opening the rear curtain 6 of the focal plane shutter 5. Reading the image signal from the image sensor 11 and the opening operation of the focal plane shutter 5 are performed in parallel with the lens shutter 8 closed. After the image signal has been read, a command is transmitted from the body microcomputer 10 to the lens microcomputer 40, and an operation to open the lens shutter 8 is instructed from the lens microcomputer 40 to the lens shutter control unit 42. After the opening operation of the lens shutter 8 is completed with the focal plane shutter 5 being opened (F), the lens microcomputer 40 notifies the body microcomputer 10 of the reset completion. The body microcomputer 10 waits for the reset completion information from the lens microcomputer 40 and the completion of the series of processes after exposure, and then confirms that the state of the shutter operation unit 30 is not pushed in and ends the photographing sequence.

  The closing charge time of the front curtain 7 and the opening charge time of the rear curtain 6 are 90 msec, and the image data reading time of the image sensor is 160 msec. By opening the rear curtain 6 of the focal plane shutter 5 in parallel with the reading of the image signal from the image pickup device 11, the interchangeable lens 2 has a shorter time than when the lens shutter 8 is not mounted. The shooting sequence can be terminated. Further, since the image signal is read from the image sensor 11 while the focal plane shutter 5 is closed, the closing operation of the lens shutter 8 is performed in parallel, so that the closing operation time of the lens shutter 8 can be shortened. The opening and closing time of the lens shutter 8 is as fast as 10 msec or less, and the time from the completion of exposure until the start of contrast AF is 170 msec (160 msec + 10 msec), and the photographing sequence can be completed in a shorter time than the conventional camera system. .

(Embodiment 2)
As a second embodiment, a camera system in which a lens barrel and a camera body are integrated will be described.

<3: Overall Configuration of Camera System 101>
FIG. 7 is a block diagram showing a schematic configuration of the camera system 101 according to the present embodiment. The camera system 101 is a lens barrel integrated digital camera system. In each configuration of the camera system 101, the same configuration as the camera system 1 is denoted by the same reference numeral. Hereinafter, the difference from the camera system 1 will be mainly described.

(3.1: Configuration of Camera System 101)
The camera system 101 mainly includes an imaging optical system L that forms an optical image of a subject, a lens shutter 8 disposed in an optical path of the imaging optical system L, and converts the optical image into an image signal to convert the optical image of the subject. An imaging unit 35 that acquires an image and a focal plane shutter 5 provided on the subject side of the imaging unit 35 are provided. The term “in the optical path” means not only between the optical components constituting the imaging optical system but also the positions near the front and rear of the imaging optical system.

  The camera system 101 does not include the body mount 4 and the lens mount 71 unlike the camera system 1. The camera system 101 body microcomputer 102 has a function including the function of the body microcomputer 10 of the camera system 1 and the function of the lens microcomputer 40. That is, a command is sent from the body microcomputer 102 to each component of the camera system 101.

<4: Operation of Camera System 101>
The camera system 101 performs the same operation as the camera system 1.

  The camera system 101 performs shooting by driving the focal plane shutter 5 with the lens shutter 8 opened, and reading the charge of the imaging unit 35 and opening operation of the focal plane shutter 5 with the lens shutter 8 closed. Do it in parallel.

  Further, the reading of the charge of the imaging unit 35 is started in a state where the focal plane shutter 5 is closed, and the reading of the charge of the imaging unit 35 and the closing operation of the lens shutter 8 are performed in parallel with the focal plane shutter 5 being closed. Do.

(effect)
(1)
Since the imaging device is exposed for shooting with the focal plane shutter, the shutter speed can be increased.

(2)
By performing the reading of the charge of the imaging unit and the opening operation of the focal plane shutter in parallel with the lens shutter closed, the time until the image sensor is exposed again after shooting can be shortened. For example, when contrast AF is performed again after shooting, the start of the contrast AF operation can be accelerated. Also, for example, it is possible to speed up the return to the live view mode after shooting.

(3)
Reading the charge of the imaging unit with the focal plane shutter closed, and reading the charge of the imaging unit and closing the lens shutter in parallel with the focal plane shutter closed, The time until the image sensor is exposed again can be further shortened.

(4)
Since it is determined whether or not the lens barrel attached to the mount of the camera body has a lens shutter, the operation can be changed according to the attached lens barrel. Further, when it is determined that the lens barrel has a lens shutter, the above-described effects can be obtained.

(5)
The lens barrel has information on whether or not the lens barrel has a lens shutter, and the camera body acquires information on whether or not the lens barrel has a lens shutter from the lens barrel. It becomes easy to determine whether or not the lens barrel attached to the mount in the main body has a lens shutter.

(Other embodiments)
Needless to say, the above-described embodiments are examples of the present invention, and the present invention is not limited to these embodiments.

(1)
The camera system and the camera body may include a quick return mirror that can be inserted into and retracted from the optical path. In that case, before the sequence described with reference to FIG. 6, the sequence described with reference to FIG. 6 is performed with the quick return mirror retracted from the optical path and the quick return mirror retracted from the optical path.

(2)
In this embodiment, the focal plane shutter 5 having a front curtain and a rear curtain is used, and the operation for performing exposure after closing the front curtain at the time of shooting to make the image sensor light-shielded has been described. As the focal plane shutter 5, an electronic shutter that performs exposure by closing the rear curtain after resetting the charge of the image sensor may be used.

  The camera system and camera body according to the present invention are suitable for a digital still camera or the like.

Block diagram showing a schematic configuration of the camera system according to the present embodiment Block diagram showing a schematic configuration of a camera body according to the present embodiment The figure which shows the operation state of the focal plane shutter which concerns on this Embodiment. Sequence diagram of shooting operation when an interchangeable lens without a lens shutter is attached The figure which shows the operation state of the lens shutter at the time of imaging | photography of the camera system which concerns on this Embodiment, and a focal plane shutter Sequence diagram of shooting operation when an interchangeable lens equipped with a lens shutter is attached Block diagram showing a schematic configuration of the camera system according to the present embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Camera system 2 Interchangeable lens 3 Camera body 4 Body mount 5 Focal plane shutter 6 Rear curtain 7 Front curtain 8 Lens shutter 10 Body microcomputer 11 Imaging element 12 Imaging element drive control part 20 Display part 21 Image display control part 30 Shutter operation Unit 31 Shutter control unit 40 Lens microcomputer 41 Focus lens drive control unit 42 Lens shutter control unit 43 Aperture unit 71 Lens mount L Imaging optical system L1 Focus lens

Claims (10)

An imaging optical system for forming an optical image of a subject;
A lens shutter disposed in the optical path of the imaging optical system;
An imaging unit that converts the optical image into an image signal to obtain an image of the subject;
A focal plane shutter provided on the subject side of the imaging unit, and taking a picture by driving the focal plane shutter with the lens shutter opened and closing the lens shutter. A camera system that performs charge readout and opening operation of the focal plane shutter in parallel.   The focal plane shutter has a front curtain and a rear curtain, and operates the front curtain so that the optical path is opened from a state where the optical path is closed by the front curtain, and in parallel with the operation of the front curtain, the optical path The camera system according to claim 1, wherein shutter driving is performed to operate the rear curtain so as to close the door.   The readout of the charge of the imaging unit is started with the focal plane shutter closed, and the readout of the charge of the imaging unit and the closing operation of the lens shutter are performed in parallel with the focal plane shutter closed. The camera system according to claim 1. A mount on which a lens barrel having an imaging optical system for forming an optical image of a subject can be mounted;
An imaging unit that converts the optical image into an image signal to obtain an image of the subject;
A focal plane shutter provided closer to the subject than the imaging unit;
A determination unit for determining whether or not the lens barrel mounted on the mount has a lens shutter;
When the determination unit determines that the lens barrel has the lens shutter, the focal plane shutter is driven with the lens shutter opened to perform shooting, and the lens shutter is closed with the lens shutter closed. A camera main body that performs reading of charges of the imaging unit and opening operation of the focal plane shutter in parallel.   The focal plane shutter has a front curtain and a rear curtain, and operates the front curtain so that the optical path is opened from a state where the optical path is closed by the front curtain, and in parallel with the operation of the front curtain, the optical path The camera body according to claim 4, wherein shutter driving is performed so as to close the camera.   The readout of the charge of the imaging unit is started with the focal plane shutter closed, and the readout of the charge of the imaging unit and the closing operation of the lens shutter are performed in parallel with the focal plane shutter closed. The camera body according to claim 4. A camera system comprising the camera body according to claim 4 and a lens barrel that can be attached to the mount.
The lens barrel has information on whether the lens barrel has the lens shutter;
The camera body is a camera system that acquires information on whether or not the lens barrel has the lens shutter from the lens barrel.   The said determination part of the said camera main body determines whether the said lens barrel has the said lens shutter based on the information regarding whether the said lens barrel has the said lens shutter. Camera system.   The focal plane shutter has a front curtain and a rear curtain, and operates the front curtain so that the optical path is opened from a state where the optical path is closed by the front curtain, and in parallel with the operation of the front curtain, the optical path The camera system according to claim 7 or 8, wherein the shutter system is operated so as to close the mouth. The readout of the charge of the imaging unit is started with the focal plane shutter closed, and the readout of the charge of the imaging unit and the closing operation of the lens shutter are performed in parallel with the focal plane shutter closed. The camera system according to claim 7 or 8.