JP2010074743A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control brightness of a live view image when starting display. <P>SOLUTION: An imaging device 1, 2 includes an imaging element 20 for imaging an object image and outputting image data, an imaging optical system "LS" for letting the object image focus on the imaging element 20, an observing optical system 8 for observing the object image, optical path switching means 4 for switching between a first optical path which guides an object light passed through the imaging optical system "LS" into the observing optical system 8 and a second optical path which guides the object light into the imaging element 20, display controlling means for letting a reproduced image based on image data outputted after being repeatedly imaged by the imaging element 20 with a state switched to the second optical path sequentially display on a display device 23, a light receiving element 11 for receiving a light passing through the first optical path, optical path opening and closing means 24 to be provided within the optical path of the observing optical system 8 and for switching passing/shielding of the light within the optical path, and operating means for performing exposure operation to be needed when starting repetitive imaging for sequential display using a signal received by the light receiving element 11 in a state in which the optical path of the observing optical system 8 is shielded and switched to the first optical path. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that includes an optical viewfinder and performs monitor display.

  There is known an imaging apparatus capable of switching between a finder observation mode for observing a subject image via a finder optical system and a live view mode for reproduction display on a display apparatus based on an image signal captured by an imaging element ( Patent Document 1).

JP 2007-41150 A

  When switching from the viewfinder observation mode to the live view mode, it is preferable to start displaying the live view image as soon as possible. For this reason, the exposure condition of the image sensor immediately after switching to the live view mode is determined based on the photometric information immediately before switching to the live view mode acquired by the photometric element arranged on the finder optical system side. . In this case, when outside light enters the viewfinder optical system from the eyepiece lens, there is a problem that the brightness of the live view image at the start of display becomes darker than when it is appropriate.

  An imaging apparatus according to the present invention captures a subject image and outputs image data, an imaging optical system that forms the subject image on the imaging device, an observation optical system for observing the subject image, and imaging Optical path switching means for switching between a first optical path that guides the subject light that has passed through the optical system to the observation optical system and a second optical path that guides the subject light to the imaging element, and the imaging element repeatedly captures an image while being switched to the second optical path. Display control means for sequentially displaying a reproduced image based on the output image data on the display device, a light receiving element for receiving light passing through the first optical path, and an optical path of the observation optical system, and passage of light in the optical path / An optical path opening / closing means for switching light shielding, and a signal received by the light receiving element in a state where the optical path of the observation optical system is shielded and switched to the first optical path, for repeated imaging for sequential display Characterized in that it comprises a calculating means for performing exposure calculation required Hajimeji.

  With the imaging device according to the present invention, the brightness of the live view image at the start of display can be appropriately controlled.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 to 3 are diagrams illustrating the configuration of a single-lens reflex electronic camera system according to an embodiment of the present invention. In FIG. 1, a lens barrel 2 of a photographing lens configured to be detachable is attached to a lens mount (not shown) of a camera body 1.

  Light L from the subject enters the camera body 1 via the lens optical system LS of the lens barrel 2 and the diaphragm 3. The subject light L incident on the camera body 1 is guided to the upper finder by a quick return mirror (hereinafter referred to as a main mirror) 4 and imaged on the focusing screen 5 before the release operation. A part of the subject light L incident on the camera body 1 is reflected downward by the sub mirror 15 and guided to the focus detection sensor 16. A detection signal from the focus detection sensor 16 is used for focus detection calculation by an AF control unit 110 (FIG. 4) described later.

  The lens driving device 17 includes a motor, a coupling gear, a coupling, and the like. The lens driving device 17 generates a driving force for moving the focus lens included in the lens optical system LS to the in-focus position during focus adjustment, and moves toward the lens barrel 2 side. introduce. The moving direction and moving amount when moving the focus lens to the in-focus position are determined based on the focus detection calculation performed by the AF control unit 110 (FIG. 4).

  The subject light L imaged on the focusing screen 5 is further incident on the pentaprism 7 via the PN liquid crystal 6. The PN liquid crystal 6 is composed of a polymer network liquid crystal, which transmits light when energized and diffuses light when de-energized. The camera body 1 performs a display indicating an area (referred to as a focus point) where the focus is detected by the PN liquid crystal 6. The display content of the PN liquid crystal 6 is observed through the eyepiece lens group 8 from the eyepiece window 26 while being superimposed on the optical observation image by the finder unit.

  The eyepiece shutter 24 allows observation light to be observed by allowing subject light to pass through when opened (FIG. 1). On the other hand, when closed (FIGS. 2 and 3), external light entering from the eyepiece window 26 to the eyepiece lens group 8 side is blocked. Since the subject light is also shielded when the eyepiece shutter 24 is closed, the observation image by the finder unit cannot be observed.

  An eyepiece shutter drive mechanism (not shown) drives the eyepiece shutter 24 to close in response to a closing instruction from an MPU 106 (FIG. 4) described later. Further, the eyepiece shutter 24 is driven to open in response to an opening instruction from the MPU 106 (FIG. 4). The eye sensor 25 is a sensor for detecting whether or not an object (camera user's face) is close to the eyepiece window 26, and the object detection status is output to the MPU 106 (FIG. 4). In the present embodiment, it is used to determine whether or not the user is looking through the eyepiece window 26. The eye sensor 25 may be anything as long as it can detect the proximity of an object. In the present embodiment, the eye sensor 25 includes a light projecting element and a light receiving element that receives reflected light reflected by an object close to the light projected by the light projecting element. If the amount of reflected light received is greater than or equal to a predetermined value, it is determined that the user is looking into the eyepiece window 26.

  The pentaprism 7 guides the incident subject light L to the eyepiece lens group 8 and also guides part of it to the prism 9. The light incident on the prism 9 enters the photometric sensor 11 through the imaging lens 10. The photometric sensor 11 captures a subject image in a range substantially equal to the observation image obtained by the finder unit. The photometric sensor 11 outputs a photoelectric conversion signal corresponding to the brightness of the subject image.

  After the release operation, the main mirror 4 is rotated upward (mirror up), and the subject light L is guided to the image sensor 20 via the shutter 18 and forms a subject image on the imaging surface. The imaging element 20 is configured by a CCD image sensor or the like provided with a plurality of photoelectric conversion elements corresponding to pixels. The image sensor 20 captures a subject image formed on the imaging surface, and outputs a photoelectric conversion signal corresponding to the brightness of the subject image.

  The in-viewfinder liquid crystal 13 displays information such as an exposure control value related to photographing. By disposing the prism 12 in front of the in-viewfinder liquid crystal 13 (to the left in FIGS. 1 to 3), the display content of the in-viewfinder liquid crystal 13 is observed separately from the optical image by the viewfinder through the eyepiece lens group 8. The The in-finder backlight 14 illuminates the in-finder liquid crystal 13.

  Circuits such as the MPU 106, the timing circuit 101, the A / D conversion circuit 102, and the ASIC 103 shown in FIG. 4 are mounted on the digital board 22. The liquid crystal display unit 23 is disposed on the back side (right side in FIGS. 1 to 3) of the camera body 1. The liquid crystal display unit 23 displays a captured image, an operation menu screen, and the like.

  FIG. 4 is a block diagram illustrating the circuit configuration of the single-lens reflex electronic camera system described above. The camera body 1 includes a timing circuit (TG) 101, an A / D conversion circuit 102, an image sensor 20, an ASIC 103, a RAM 104, a liquid crystal display unit 23, an MPU 106, a shutter drive mechanism 107, and a mirror drive. A mechanism 108, an operation member 109, an AF control unit 110, and an AE control unit 111 are provided, and a detachable recording medium 105 is mounted.

<Camera body>
A timing circuit (TG) 101 generates a predetermined timing signal and supplies the timing signal to each of the A / D conversion circuit 102, the ASIC 103, and the image sensor 20. The A / D conversion circuit 102 converts a photoelectric conversion signal (analog image signal) from the image sensor 20 into a digital signal. The ASIC 103 performs predetermined image processing on the image signal after digital conversion, and further performs compression processing as necessary.

  The RAM 104 is a working memory that temporarily stores image data during processing by the ASIC 103. The recording medium 105 includes a nonvolatile memory that stores image data processed by the ASIC 103 as an image file. The liquid crystal display unit 23 displays a reproduced image based on the image data processed by the ASIC 103.

  The MPU 106 is a microprocessor, inputs a signal output from each block, performs a predetermined calculation, and outputs a control signal based on the calculation result to each block. The MPU 106 and the ASIC 103 transmit and receive mutual control signals by serial communication.

  The shutter drive mechanism 107 performs charge and drive control of the focal plane shutter 18 (FIGS. 1 to 3) in accordance with an instruction sent from the MPU 106. The mirror drive mechanism 108 controls the mirror up drive and the mirror down drive of the main mirror 4 in accordance with an instruction sent from the MPU 106.

  The operation member 109 outputs a setting / switching signal corresponding to various settings and selection operations to the MPU 106. The operation member 109 has an exposure mode setting dial for setting an exposure calculation mode (P mode, S mode, A mode, M mode), a sensitivity setting dial for setting imaging sensitivity (ISO sensitivity), and a live view switch. , AF switch, half-press switch, full-press switch, and the like.

  The P mode is a mode in which the shutter speed and the aperture value are automatically controlled according to a predetermined program diagram. The S mode is a mode in which the aperture value is automatically controlled according to the set shutter speed. The A mode is a mode in which the shutter speed is automatically controlled according to the set aperture value. The M mode is a manual mode in which a deviation from the appropriate exposure is calculated using the set shutter speed and aperture value.

  The live view switch is a switch for manually starting / ending a live view display operation described later. The live view display operation can be automatically started / finished based on the change in the output signal of the eye sensor 25. The AF switch is a switch for starting an automatic focus adjustment (AF) operation.

  Each of the half-press switch and the full-press switch outputs an ON signal to the MPU 106 in conjunction with a pressing operation of a release button (not shown). The half-press on signal from the half-press switch is output when the release button is pressed down to about half of the normal stroke, and the output is canceled when the half-stroke pressing operation is released. The full push on signal from the full push switch is output when the release button is pushed down to the normal stroke, and the output is released when the normal stroke push down operation is released.

  The AF control unit 110 includes a focus detection sensor 16 (FIGS. 1 to 3). The AF control unit 110 performs a known phase difference type focus detection calculation using a detection signal from the focus detection sensor 16. By this calculation, a focus adjustment state (defocus amount) by the lens barrel 2 is obtained, and a movement amount of a focus lens (not shown) constituting the lens optical system LS is calculated according to the defocus amount. A signal indicating the amount of movement of the focus lens is transmitted to the lens barrel 2 via the MPU 106.

  The AE control unit 111 includes a photometric sensor 11 (FIGS. 1 to 3). The AE control unit 111 calculates the subject brightness using the detection signal from the photometric sensor 11. The AE control unit 111 further uses the imaging sensitivity set by the sensitivity setting dial, the lens information acquired by the MPU 106, and the calculated subject brightness, according to the exposure calculation mode set by the exposure mode setting dial. Calculation is performed to determine the aperture value AV and the shutter speed TV.

  The MPU 106 communicates with the lens CPU 501 on the lens barrel 2 side attached to the camera body 1. Through communication between the camera body 1 and the lens barrel 2, lens information such as an aperture value and lens data is transmitted from the lens barrel 2 to the camera body 1, while lens control information such as the moving amount of the focus lens and a drive instruction is received. It is transmitted from the camera body 1 to the lens barrel 2 side.

<Tube>
The lens barrel 2 is provided with a lens CPU 501, a focus drive mechanism 502, and an aperture drive mechanism 503. The lens CPU 501 communicates with the MPU 106 on the camera body 1 side. The lens CPU 501 transmits lens information such as an aperture value and lens data to the camera body 1 side, and acquires lens control information such as the moving amount of the focus lens and a drive instruction from the camera body 1.

  The focus driving mechanism 502 moves the focus lens in a predetermined direction by a predetermined amount by the driving force transmitted from the camera body 1 side in response to an instruction sent from the lens CPU 501. The aperture driving mechanism 503 drives the aperture 3 (FIGS. 1 to 3) by a predetermined number of stages so as to obtain an aperture value corresponding to an instruction sent from the lens CPU 501.

<Live view>
The live view display refers to display of a monitor image that causes the liquid crystal display unit 23 to sequentially reproduce and display images repeatedly captured at a predetermined time interval (for example, 30 frames / second) by the image sensor 20 before a shooting instruction. When the main mirror 4 is up (FIG. 3), the subject luminous flux is not guided to the viewfinder, so that the photographer cannot confirm the subject image via the eyepiece lens group 8. Therefore, a monitor image is displayed on the liquid crystal display unit 23 of the camera body 1 so that the subject image can be observed on the liquid crystal display unit 23.

  The MPU 106 closes the eyepiece shutter 24 during live view display. This prevents adverse effects caused by back-entered light that has entered the camera body 1 from the eyepiece window 26 wrap around the photometric sensor 11 or wrap around the imaging surface of the image sensor 20.

  Further, the MPU 106 instructs the ASIC 103 to switch from a driving signal for normal photographing (for finder observation) to a driving signal for live view during live view display. Then, the timing circuit (TG) 101 supplies a drive signal for live view to the image sensor 20, the A / D conversion circuit 102, and the ASIC 103. The RAM 104 is controlled to temporarily store image data before the ASIC 103 performs image processing, after image processing, and during image processing. As a result, the next frame can be captured without waiting for the end of the processing for the captured image data of the previous frame. Display data is generated in order from the image of the frame for which processing has been completed, and sequentially displayed on the liquid crystal display unit 23 (live view display).

<AE (automatic exposure) calculation during live view>
Since the subject light L is not guided to the photometric sensor 11 (FIG. 3) when the main mirror 4 is up, the exposure calculation using the photometric sensor 11 cannot be performed. Therefore, the exposure calculation is performed based on the image signal acquired by the image sensor 20 during live view display. For example, the MPU 106 divides an image into a predetermined number (for example, 6 × 8 × 48) regions, and calculates an average value of signal values included in each divided region. The MPU 106 extracts a region where the calculated average value exceeds a predetermined determination threshold value from the predetermined number of regions, and sets a value obtained by further averaging the average value in the extraction region as subject luminance information.

  The MPU 106 sends subject luminance information to the AE control unit 111. The AE control unit 111 performs an exposure calculation using the set imaging sensitivity, lens information acquired by the MPU 106, and subject brightness acquired from the MPU 106, and determines an aperture value AV and a shutter speed TV.

  Since the present embodiment is characterized by an operation at the time of switching to / cancelling the live view mode in the single-lens reflex camera system, the control for this will be mainly described below.

<Automatic switching>
The camera body 1 of the present embodiment automatically switches to the live view mode (starts live view display) / cancels (ends live view display) automatically based on a change in the output signal from the eye sensor 25. Is provided. The detection signal from the eye sensor 25 decreases when the photographer's eye (face) comes close to the eyepiece window 26 and becomes less than a predetermined value, and increases when the photographer's eye (face) moves away from the eyepiece window 26. To a predetermined value or more.

  In the automatic switching mode, when the photographer's eye (face) is close to the eyepiece window 26, the live view mode is canceled (that is, switching to the viewfinder observation mode), and the photographer's eye (face) is placed in the eyepiece window. When the user is away from H.26, the live view mode is switched.

  FIG. 5 is a flowchart for explaining the flow of processing executed by the MPU 106 in the automatic switching mode. When the “automatic switching mode” is set to ON in the operation menu setting, the MPU 106 activates a program for performing the processing shown in FIG.

  In step S <b> 10 of FIG. 5, the MPU 106 determines whether or not “no face” based on the change in the output signal from the eye sensor 25. The MPU 106 makes a positive determination in step S10 when the output signal of the eye sensor 25 is greater than or equal to a predetermined value, and proceeds to step S20. When the output signal of the eye sensor 25 is less than the predetermined value, the MPU 106 makes a negative determination in step S10 and proceeds to step S170.

  In step S20, the MPU 106 sends an instruction to an eyepiece shutter drive mechanism (not shown), drives the eyepiece shutter 24 to close, and proceeds to step S30. In step S <b> 30, the MPU 106 sends an instruction to the AE control unit 111 to perform photometry using a detection signal from the photometry sensor 11. The AE control unit 111 performs a predetermined calculation using the subject brightness calculated based on the detection signal and the lens information acquired by the MPU 106, and the exposure condition (live view image) necessary for starting the live view. Storage time, imaging sensitivity, etc.).

  In step S40, the MPU 106 sends an instruction to the mirror drive mechanism 108 to start up driving of the main mirror 4 and proceeds to step S50. In step S50, the MPU 106 starts the live view display described above, and proceeds to step S60. In step S60, the MPU 106 performs photometry based on an image signal acquired during live view display. The MPU 106 calculates subject luminance information by performing AE (automatic exposure) calculation during the live view based on the image signal, and proceeds to step S70.

  In step S70, the MPU 106 sends an instruction to the AE control unit 111 to perform exposure calculation using the subject luminance information and the subject luminance information, determines the aperture value AV and the shutter speed TV, and proceeds to step S80.

  In step S80, the MPU 106 determines whether or not the release switch has been turned ON. The MPU 106 makes an affirmative decision in step S <b> 80 and proceeds to step S <b> 90 when a full push on signal is input from the full push switch constituting the operation member 109. If the full push-on signal is not input from the full push switch, the MPU 106 makes a negative determination in step S80 and proceeds to step S100.

  In step S90, the MPU 106 performs shooting processing and proceeds to step S100. Details of the photographing process will be described later. In step S <b> 100, the MPU 106 determines whether there is “no face” based on the change in the output signal from the eye sensor 25. When the output signal of the eye sensor 25 is equal to or greater than the predetermined value, the MPU 106 makes an affirmative decision in step S100 and proceeds to step S110. If the output signal of the eye sensor 25 is less than the predetermined value, the MPU 106 makes a negative determination in step S100 and proceeds to step S150.

  In step S110, the MPU 106 determines whether or not an end operation has been performed. When the “automatic switching mode” is set to OFF in the operation menu setting, the MPU 106 makes a positive determination in step S110 and proceeds to step S120. If the “automatic switching mode” is not set to OFF, the MPU 106 makes a negative determination in step S110 and returns to step S60. When returning to step S60, the live view display is continued.

  In step S120, the MPU 106 ends the live view display and proceeds to step S130. In step S130, the MPU 106 sends an instruction to an eyepiece shutter drive mechanism (not shown) to drive the eyepiece shutter 24 to open, and proceeds to step S140. In step S140, the MPU 106 sends an instruction to the mirror drive mechanism 108, starts the down drive of the main mirror 4, and ends the process shown in FIG.

  In step S150, which proceeds after making a negative determination in step S100, the MPU 106 ends the live view display and proceeds to step S160. In step S160, the MPU 106 sends an instruction to an eyepiece shutter drive mechanism (not shown), drives the eyepiece shutter 24 to open, and proceeds to step S170. In step S170, the MPU 106 sends an instruction to the mirror driving mechanism 108 to start down driving of the main mirror 4 and proceeds to step S180.

  In step S180, the MPU 106 sends an instruction to the AE control unit 111, performs photometry using the detection signal from the photometry sensor 11, and proceeds to step S190. The AE control unit 111 calculates subject luminance information by performing AE (automatic exposure) calculation based on the detection signal.

  In step S190, the MPU 106 sends an instruction to the AE control unit 111, determines the aperture value AV and the shutter speed TV, and proceeds to step S200.

  In step S200, the MPU 106 determines whether or not the release switch has been turned ON. The MPU 106 makes an affirmative decision in step S <b> 200 and proceeds to step S <b> 210 when a full push-on signal is input from the full push switch constituting the operation member 109. If the full-press on signal is not input from the full-press switch, the MPU 106 makes a negative determination in step S200 and returns to step S10.

  In step S210, the MPU 106 performs shooting processing and proceeds to step S220. Details of the photographing process will be described later. In step S220, the MPU 106 determines whether an end operation has been performed. When the “automatic switching mode” is set to OFF in the operation menu setting, the MPU 106 makes an affirmative determination in step S220 and ends the process of FIG. If the “automatic switching mode” is not set to OFF, the MPU 106 makes a negative determination in step S220 and returns to step S10.

<Shooting process in live view mode>
The flow of shooting processing in the live view mode will be described with reference to the flowchart illustrated in FIG. In step S91 of FIG. 6, the MPU 106 initializes the image sensor 20 (charge discharge or the like), and proceeds to step S92. In step S92, the MPU 106 causes the image sensor 20 to store charge for photographing and sweep out the stored charge, and then proceeds to step S93.

  In step S93, the MPU 106 sends an instruction to the ASIC 103, performs predetermined image processing on the captured image, and proceeds to step S94.

  In step S94, the MPU 106 sends an instruction to the ASIC 103 to record the image file on the recording medium 105, and the processing in FIG.

<Shooting process in viewfinder observation mode>
A flow of photographing processing in the finder observation mode will be described with reference to a flowchart illustrated in FIG. In step S211 of FIG. 7, the MPU 106 sends an instruction to the mirror drive mechanism 108 to start up-drive of the main mirror 4 and proceeds to step S212.

  In step S212, the MPU 106 initializes the image sensor 20 (charge discharge or the like), and proceeds to step S213. In step S213, the MPU 106 causes the image sensor 20 to store charge for photographing and sweep out the stored charge, and the process proceeds to step S214.

  In step S214, the MPU 106 sends an instruction to the mirror drive mechanism 108 to start down driving of the main mirror 4 and proceeds to step S215. In step S215, the MPU 106 sends an instruction to the ASIC 103, performs predetermined image processing on the captured image, and proceeds to step S216.

  In step S216, the MPU 106 sends an instruction to the ASIC 103 to record the image file on the recording medium 105, and the processing in FIG.

<Manual switching>
When the “automatic switching mode” is set to OFF in the operation menu setting, the MPU 106 switches to the live view mode when an operation signal is input from a live view switch (not shown) constituting the operation member 109. The MPU 106 cancels the live view mode (that is, switches to the viewfinder observation mode) when an operation signal is input again from a live view switch (not shown).

  FIG. 8 is a flowchart for explaining the flow of processing executed by the MPU 106 during manual switching. The MPU 106 activates a program for performing the processing shown in FIG. 8 when the “automatic switching mode” is set to OFF in the operation menu setting.

  The processing according to FIG. 8 and the processing according to FIG. 5 are different in the processing in step S10B and step S100B, and therefore, these differences will be mainly described.

  In step S10B, the MPU 106 determines whether or not the live view switch is turned on. The MPU 106 makes an affirmative decision in step S <b> 10 </ b> B and proceeds to step S <b> 20 when an ON operation signal is input from a live view switch (not shown) constituting the operation member 109. The MPU 106 makes a negative determination in step S <b> 10 </ b> B when no on-operation signal is input from a live view switch (not shown) constituting the operation member 109, and proceeds to step S <b> 180.

  In step S100B, the MPU 106 determines whether the live view switch is turned on. The MPU 106 makes an affirmative decision in step S <b> 100 </ b> B and proceeds to step S <b> 110 when an on-operation signal is input from a live view switch (not shown) configuring the operation member 109. The MPU 106 makes a negative determination in step S <b> 100 </ b> B when the on-operation signal is not input from a live view switch (not shown) constituting the operation member 109, and proceeds to step S <b> 150.

According to the embodiment described above, the following operational effects can be obtained.
(1) The electronic camera system includes a first optical path that guides the subject light L to the viewfinder (an optical path that reflects the main mirror 4 and travels upward in FIG. 1), and a second optical path that guides the subject light L to the image sensor 20 ( 3 is provided, and the monitor image is displayed in a live view on the liquid crystal display unit 23 while being switched to the second optical path by the main mirror 4. In this case, the photometric sensor 11 that receives light passing through the first optical path when the optical path of the finder section is shielded by the eyepiece shutter 24 provided in the optical path of the finder section and is switched to the first optical path. The exposure calculation required at the start of repeated imaging for live view display is performed using the received light signal. Thereby, it is possible to prevent an adverse effect on the exposure calculation due to the back-entering light from the eyepiece window 26 wrapping around the photometric sensor 11 of the finder unit. That is, it is possible to prevent the brightness of the image at the start of live view display from becoming darker than when it is appropriate.

(2) The exposure condition of the image sensor 20 immediately after switching to the live view mode based on the photometric information immediately before switching to the live view mode acquired using the photometric sensor 11 that receives light passing through the first optical path. I decided to decide. Thereby, the display of the live view image can be started earlier than when the image pickup device 20 performs preliminary imaging for the purpose of obtaining subject luminance information without displaying on the liquid crystal display unit 23.

(3) Since the eyepiece shutter 24 and the main mirror 4 are driven and controlled so that the eyepiece shutter 24 blocks the optical path of the finder unit and then switches to the second optical path, the eyepiece shutter 24 is switched to the first optical path. It is possible to reliably prevent reverse incident light from the eyepiece window 26.

(4) Since the exposure calculation is performed using the light receiving signal from the photometric sensor 11 after the light path of the finder portion is blocked and before switching to the second optical path, the light receiving signal from which the reverse incident light is excluded Since the exposure can be calculated using, the live view image at the start of the live view display can be set to an appropriate brightness.

(Modification 1)
In the embodiment described above, photometry is performed using the detection signal from the photometry sensor 11 (step S30), and the image sensor 20 required at the start of the live view is calculated using the subject luminance and lens information based on the photometry result. The exposure conditions (live view image accumulation time, imaging sensitivity, etc.) were determined. The determined exposure condition is used for at least the first imaging of live view display. In addition, you may make it use not only for the 1st imaging but for 2 times imaging. After starting the live view display in step S50, photometry is performed using the image pickup signal from the image sensor 20 (step S60), and is necessary for subsequent live view display by calculation using subject luminance information based on the photometry result. The exposure conditions (accumulation time for live view image, imaging sensitivity, etc.) of the image sensor 20 are determined.

(Modification 2)
The main mirror 4 may be driven and controlled so that the first optical path is switched to the second optical path after a predetermined time has passed since the instruction to close the eyepiece shutter 24 has been sent. The predetermined time in this case corresponds to the time required for closing the eyepiece shutter 24. Also in the case of the modified example 2, the reverse incident light from the eyepiece window 26 can be reliably prevented while being switched to the first optical path.

  According to the second modification, since the exposure calculation is performed using the light reception signal by the photometry sensor 11 after the predetermined time has elapsed and before switching to the second optical path, the light reception signal from which the reverse incident light is excluded. Can be used to calculate the exposure. As a result, the live view image at the start of the live view display can be set to an appropriate brightness.

(Modification 3)
The main mirror 4 may be driven and controlled so that the first optical path is switched to the second optical path after the light reception signal from the photometric sensor 11 decreases after the eyepiece shutter 24 blocks the optical path of the viewfinder. When the light received by the photometric sensor 11 includes reverse incident light, the received light signal from the photometric sensor 11 decreases when the eyepiece shutter 24 is closed. By controlling the switching to the second optical path after waiting for a decrease in the received light signal, it is possible to reliably prevent back-entering light from the eyepiece window 26 while switching to the first optical path.

  According to the third modification, the exposure calculation is performed using the light reception signal from the photometry sensor 11 after the light reception signal from the photometry sensor 11 is reduced and before switching to the second optical path. The live view image can be set to appropriate brightness.

(Modification 4)
In the above description, the eyepiece shutter 24 is used to switch the passage / light-blocking of light in the optical path of the finder section. Dimming that can reversibly change the transmittance by applying a liquid crystal element (for example, PN liquid crystal) instead of the eyepiece shutter 24 or applying a voltage, as long as it prevents back-entering light from the eyepiece window 26 during light shielding. You may comprise by a mirror etc. In the present invention, the reverse incident light level incident on the photometric sensor 11 only needs to be suppressed to a level that does not have an adverse effect. Therefore, it may be constituted by a light reducing member that attenuates the reverse incident light to a predetermined light amount or less even if it is not completely light-shielded.

  The above description is merely an example, and is not limited to the configuration of the above embodiment.

It is a figure explaining the structure of the single-lens reflex electronic camera system by one embodiment of this invention. It is a figure explaining the structure of the single-lens reflex electronic camera system by one embodiment of this invention. It is a figure explaining the structure of the single-lens reflex electronic camera system by one embodiment of this invention. It is a block diagram which illustrates the circuit structure of a single-lens reflex electronic camera system. It is a flowchart explaining the flow of the process which MPU performs in the automatic switching mode. It is a flowchart explaining the flow of an imaging process. It is a flowchart explaining the flow of an imaging process. It is a flowchart explaining the flow of the process which MPU performs at the time of manual switching.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera body 2 ... Lens tube 8 ... Eyepiece lens group 11 ... Photometric sensor 20 ... Image sensor 23 ... Liquid crystal display part 26 ... Eyepiece window 106 ... MPU
108 ... Mirror drive mechanism 109 ... Operation member 111 ... AE control unit

Claims (8)

An image sensor that captures a subject image and outputs image data;
An imaging optical system for forming a subject image on the imaging device;
An observation optical system for observing the subject image;
Optical path switching means for switching between a first optical path that guides the subject light that has passed through the imaging optical system to the observation optical system and a second optical path that guides the subject light to the imaging element;
Display control means for sequentially displaying on the display device a reproduced image based on image data that is repeatedly captured and output by the imaging element in a state of being switched to the second optical path;
A light receiving element that receives light passing through the first optical path;
An optical path opening / closing means that is provided in the optical path of the observation optical system and switches between passage and shading of light in the optical path;
Using a signal received by the light receiving element in a state where the optical path of the observation optical system is shielded and switched to the first optical path, an exposure calculation necessary at the start of repeated imaging for the sequential display is performed. An imaging device comprising: an arithmetic means for performing the operation. The imaging device according to claim 1,
The said calculating means performs the exposure calculation with respect to at least 1st of the said repeated imaging, The imaging device characterized by the above-mentioned. The imaging device according to claim 1,
An imaging apparatus comprising: a control unit that controls the optical path switching unit and the optical path switching unit so that the optical path switching unit switches the second optical path after blocking the optical path of the observation optical system. The imaging device according to claim 3.
The imaging apparatus according to claim 1, wherein the calculation means performs the exposure calculation using a light reception signal after the light shielding and before switching to the second optical path. The imaging device according to claim 1,
Control means for controlling the optical path switching means and the optical path switching means to switch to the second optical path after a lapse of a predetermined time after sending an instruction to block the optical path of the observation optical system to the optical path switching means. An imaging device that is characterized. The imaging apparatus according to claim 5,
The imaging device, wherein the calculation means performs the exposure calculation using a light reception signal before switching to the second optical path after the predetermined time has elapsed. The imaging device according to claim 1,
The optical path opening / closing means and the optical path switching means are respectively controlled so that the signal received by the light receiving element decreases after the instruction to block the optical path of the observation optical system is sent to the optical path opening / closing means, and then the optical path switching means is switched to the second optical path. An image pickup apparatus comprising control means for performing the operation. The imaging apparatus according to claim 7,
The imaging device, wherein the calculation means performs the exposure calculation using a light reception signal after the decrease and before switching to the second optical path.

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