JP2005292517A - Imaging apparatus and photographing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of preventing a picture displayed by a display means when driving a mirror unit from getting hard-to-view. <P>SOLUTION: The imaging apparatus includes a finder optical system capable of observing a subject image by using luminous flux from a photographic lens (103); the mirror unit switched to a 1st state where it reflects the luminous flux toward the finder optical system and a 2nd state where it makes the luminous flux reach the imaging device (106) and then driven; the display means (107) for displaying the picture generated by using output from the imaging element; and a control means (135) for controlling the driving of the display means. The control means controls the display means to display prescribed information before the mirror unit is switched from the 2nd state to the 1st state and then driven. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus that switches between a first state in which a light beam from a photographing lens is guided to a finder optical system and a second state in which the light beam reaches an image sensor.

  In a single-lens reflex camera that is one of the imaging devices, when observing an object image using an optical finder, the light beam emitted from the photographing lens is reflected by a reflecting mirror disposed on the image plane side with respect to the photographing lens, It leads to an optical viewfinder including a pentaprism. Thereby, the photographer can view the object image formed by the photographing lens as a normal image. At this time, the reflection mirror is provided obliquely on the photographing optical path.

  On the other hand, when photographing an object image, the reflecting mirror is retracted from the photographing optical path so that the light flux from the photographing lens reaches the imaging medium (imaging device such as a film or a CCD). When the photographing operation is completed, the reflecting mirror is obliquely installed on the photographing optical path.

  Here, some single-lens reflex digital cameras can manually select focus adjustment by a phase difference detection method and focus adjustment by a contrast detection method (for example, see Patent Document 1). When the reflecting mirror is obliquely arranged on the photographing optical path, focus adjustment is performed by the phase difference detection method, and when the reflecting mirror is retracted from the photographing optical path, the focus by the contrast detection method is used using the output of the image sensor. Some perform adjustment (see, for example, Patent Document 2). In the camera of Patent Document 2, it is possible to perform focus adjustment by a contrast detection method while displaying (electronically displaying) an image read from the image sensor on a display unit.

  In general, the focus adjustment by the contrast detection method has a problem that it takes time to reach an in-focus state because the evaluation function value is obtained while slightly moving the imaging lens in the optical axis direction. In the focus adjustment by the phase difference detection method, the photographing lens is only moved by the detected defocus amount, so that the time until the in-focus state is achieved is shorter than that in the contrast detection method.

  Therefore, in order to speed up the direction determination in the focus control by the contrast detection method, there is one in which a step is provided on the light detection surface of the image sensor (for example, Patent Document 3). That is, a plurality of image signals are collected by changing the optical path length by a minute distance, the in-focus direction is determined based on the collected image signals, and the imaging lens is moved to the in-focus position in the determined in-focus direction. It is to be moved.

  In addition, there is a single-lens reflex type digital camera in which a phase difference detection type focus detection unit is provided in each of the lens apparatus and the camera body (for example, Patent Document 4). In this camera, when a mirror for switching the optical path is arranged on the photographing optical path, focus detection is performed by a focus detection unit in the camera body, and in the lens apparatus when the mirror is retracted from the photographing optical path. The focus detection unit performs focus detection. That is, even when the mirror is in any state, focus detection by the phase difference detection method is performed by the focus detection unit, so that the focus adjustment operation can be speeded up.

  However, in the camera proposed in Patent Document 3, a high-quality image cannot be obtained because pixels with a short optical path length and pixels with a long optical path length coexist. Here, if the optical path length difference between the short optical path length pixel and the long optical path length pixel is shortened, the image quality is improved, but it becomes difficult to determine the direction in the focus control, and high-speed focus control cannot be performed.

  Further, in the camera proposed in Patent Document 4, the amount of photographing light flux is reduced by the mirror for guiding the object light to the focus detection unit in the lens device, and the focus detection unit is provided on the lens device and the camera body. Therefore, there are disadvantages such as an increase in size and cost of the camera system.

Therefore, as an imaging apparatus that can achieve the high speed of the focus adjustment operation while solving the problems of Patent Documents 3 and 4 described above, an optical viewfinder (OVF) or an electronic viewfinder (EVF) is provided. In either case of observing a subject image using a lens, it is conceivable that the light beam from the photographing lens is guided to a focus detection unit that performs focus detection by a phase difference detection method. Specifically, the mirror unit is driven to be switched between a first optical path division state in which the light beam from the photographing lens is guided to the optical viewfinder and the focus detection unit, and a second optical path division state in which the light beam is led to the image sensor and the focus detection unit. It can comprise so that it may do.
JP 2001-275033 A (paragraph numbers 0053 to 0057, FIG. 5) JP 2001-125173 A (paragraph numbers 0062 to 0067, FIGS. 8 and 9) JP 2001-215406 A (paragraph numbers 0034 to 0041, FIG. 6) Japanese Unexamined Patent Publication No. 2000-162494 (paragraph numbers 0019 to 0023, FIG. 2)

  In the imaging apparatus that switches the mirror unit in the first and second optical path division states, if the mirror unit is operated while the subject image is displayed on the electronic viewfinder, the light flux incident on the imaging element from the imaging optical system is changed. The movement of the mirror unit may obstruct the image displayed on the electronic viewfinder.

  An image pickup apparatus according to the present invention includes an image pickup device that photoelectrically converts a subject image formed by a light beam from a photographing lens, a finder optical system that enables observation of the subject image using the light beam, and the light beam that passes through the finder optical system. A mirror unit that is driven to switch between a first state that reflects toward the image sensor and a second state that causes the light beam to reach the image sensor, and a display unit that displays an image generated using the output of the image sensor And control means for controlling driving of the display means. Then, the control means causes the display means to display specific information before the mirror unit is driven to be switched from the second state to the first state.

  According to the present invention, since specific information is displayed on the display unit before the mirror unit is switched from the second state to the first state, an unsightly image accompanying the switching drive of the mirror unit is displayed on the display unit. Can be prevented from being displayed.

  Examples of the present invention will be described below.

  Hereinafter, a camera system (imaging system) that is Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 6 is a schematic diagram showing the configuration of the camera system in the present embodiment. This camera system has a camera body (imaging device) and a lens device that is detachably attached to the camera body.

  The camera is a single-plate digital color camera using an image sensor such as a CCD or CMOS sensor, and obtains an image signal representing a moving image or a still image by driving the image sensor continuously or once. Here, the imaging element is an area sensor of a type that converts the exposed light into an electrical signal for each pixel, accumulates charges according to the amount of received light, and reads the accumulated charges.

In FIG. 6, reference numeral 101 denotes a camera body, and reference numeral 102 denotes a lens device that can be detached from the camera body 101. A photographing optical system 103 is provided in the lens device 102.
The lens device 102 is electrically and mechanically connected to the camera body 101 via a known mount mechanism. Then, by attaching the lens device 102 having different focal lengths to the camera body 101, it is possible to obtain shooting screens having various angles of view.

  In the lens device 102, a focus lens, which is a part of the photographing optical system 103, is moved in the direction of the optical axis L1 via a drive mechanism (not shown), or the focus lens is moved to a flexible transparent elastic member or liquid. It is composed of a lens, and the focus of the photographic optical system is adjusted by changing the refractive power by changing the interface shape.

  Reference numeral 106 denotes an image sensor housed in a package 124. In the optical path from the photographic optical system 103 to the image sensor 106, the cutoff frequency of the photographic optical system 103 is limited so that a spatial frequency component higher than necessary of the object image (optical image) is not transmitted to the image sensor 106. An optical low-pass filter 156 is provided. The photographing optical system 103 is formed with an infrared cut filter (not shown).

  The signal read from the image sensor 106 is displayed on the display unit 107 as image data after being subjected to predetermined processing as will be described later. The display unit 107 is attached to the back of the camera body 101 so that the user can directly observe the display on the display unit 107.

  If the display unit 107 is composed of an organic EL spatial modulation element, a liquid crystal spatial modulation element, a spatial modulation element using fine particle electrophoresis, or the like, the power consumption can be reduced and the display unit 107 can be made thin. . Thereby, the power saving and size reduction of the camera body 1 can be achieved.

  Specifically, the image sensor 106 is a CMOS process compatible sensor (hereinafter abbreviated as a CMOS sensor) which is one of the amplification type solid-state image sensors. One of the features of the CMOS sensor is that the MOS transistors in the area sensor and the peripheral circuits such as the image sensor drive circuit, AD converter circuit, and image processing circuit can be formed in the same process. It can be greatly reduced. In addition, it has a feature that random access to an arbitrary pixel is possible, reading out for a display is easy, and real-time display can be performed at a high display rate on the display unit 107.

  The image sensor 106 uses the above-described features to perform a display image output operation (reading in a region where a part of the light receiving region of the image sensor 106 is thinned) and a high-definition image output operation (reading in the entire light receiving region). Do.

  Reference numeral 111 denotes a movable half mirror (first mirror member) that reflects a part of the light flux from the photographing optical system 103 and transmits the remaining part. The half mirror 111 has a refractive index of about 1.5 and a thickness of 0.5 mm. Reference numeral 105 denotes a focusing screen arranged on a predetermined image plane of an object image formed by the photographing optical system 103, and 112 denotes a pentaprism.

  Reference numeral 109 denotes a finder lens for observing an object image formed on the focusing screen, and actually includes three finder lenses (109-1, 109-2, 109-3 in FIG. 1). . The focusing screen 105, the pentaprism 112, and the finder lens 109 constitute a finder optical system.

  A movable sub-mirror (second mirror member) 122 is provided behind the half mirror 111 (on the image plane side), and reflects the light beam close to the optical axis L1 out of the light beam transmitted through the half mirror 111, thereby the focus detection unit. (Focus detection means) 121. The sub mirror 122 rotates around a rotation shaft 125 (see FIG. 1 and the like) described later, and is housed in the lower part of the mirror box according to the movement of the half mirror 111. That is, the sub mirror 122 does not operate integrally with the half mirror, and can advance and retreat independently with respect to the photographing optical path.

  The focus detection unit 121 receives the light beam from the sub-mirror 122 and performs focus detection by the phase difference detection method.

  The optical path splitting system composed of the half mirror 111 and the sub mirror 122 can be switched between the first to third optical path splitting states as will be described later. In the first optical path division state (first state), the light beam from the photographing optical system 103 is reflected by the half mirror 111 and guided to the finder optical system, and the light beam transmitted through the half mirror 111 is reflected by the sub mirror 122. To the focus detection unit 121.

  In the first optical path division state, the object image formed by the light beam can be observed through the finder lens 109 and the focus detection unit 121 can perform focus detection. In addition, in FIG. 6, the 1st optical path division | segmentation state is shown.

  In the second optical path division state (transmission / reflection state), the light beam from the photographing optical system 103 passes through the half mirror 111 and reaches the image sensor 106, and is reflected by the half mirror 111 and guided to the focus detection unit 121. It is burned. In the second optical path division state, captured image data can be displayed in real time on the display unit 107, or high-speed continuous shooting can be performed. Here, in the second optical path division state, since it is possible to perform imaging with the image sensor 106 without operating the optical path division system, high-speed continuous shooting is performed by speeding up the operation in the signal processing system. Can do.

  In the second optical path division state, the focus detection unit 121 can perform focus detection. For this reason, it is possible to perform high-speed focus adjustment by the phase difference detection method even during monitoring by the display unit 107. In the second optical path division state, since the light beam from the photographing optical system 103 reaches the image sensor 106, the contrast detection method using the output of the image sensor 106 in addition to the focus adjustment by the phase difference detection method described above. You may make it perform the focus adjustment by.

  In the third optical path division state (retracted state), the light beam from the photographing optical system 103 is directly guided to the image sensor 106. In this state, the half mirror 111 and the sub mirror 122 are retracted from the photographing optical path. The third optical path division state is used to generate a high-definition image suitable for large prints and the like.

  The optical path splitting system is driven by a mirror driving mechanism having an electromagnetic motor and a gear train (not shown), and the positions of the half mirror 111 and the sub mirror 122 are changed to change between the first to third optical path splitting states. Can be switched with. The drive control of the mirror drive mechanism is performed by a camera system control circuit 135 to be described later via a mirror drive control circuit 145.

  Here, in order to switch the above-described three optical path division states at high speed, the half mirror 111 is formed of a transparent resin to reduce the weight. A polymer thin film having birefringence is attached to the back surface of the half mirror 111 (the surface on the sub mirror 122 side in FIG. 6). This is because a stronger low-pass effect is provided in correspondence with the case where the image is not captured using all the pixels of the image sensor 106 as in the case of monitoring an image (real-time display) or when performing high-speed continuous shooting.

  In addition, by forming a fine pyramid-like periodic structure having a pitch smaller than the wavelength of visible light on the surface of the half mirror 111 and acting as a so-called photonic crystal, light caused by a difference in refractive index between air and resin It is also possible to reduce the surface reflection of the light and increase the light utilization efficiency. If comprised in this way, it can prevent that a ghost generate | occur | produces by the multiple reflection of the light in the back surface and the surface of the half mirror 111 in a 2nd optical path division | segmentation state.

  Reference numeral 104 denotes a movable flash light emitting unit, which is movable between a storage position stored in the camera main body 101 and a light emission position protruding from the camera main body 101. Reference numeral 113 denotes a focal plane shutter for adjusting the amount of light incident on the image plane, and reference numeral 119 denotes a main switch for starting the camera body 101.

  Reference numeral 120 denotes a release button that is pressed in two steps. A shooting preparation operation (photometry operation, focus adjustment operation, etc.) is started by a half-press operation (SW1 ON), and a shooting operation is performed by a full-press operation (SW2 ON). (Recording of image data read from the image sensor 106 to a recording medium) is started.

  Reference numeral 123 denotes a finder mode changeover switch, which can be switched between the OVF mode and the EVF mode each time the switch is pressed. Reference numeral 180 denotes an information display unit in the optical viewfinder for displaying specific information on the focusing screen 105.

  FIG. 7 is a block diagram showing an electrical configuration of the camera system in the present embodiment. Here, the same reference numerals are used for the same members as those described in FIG. First, an explanation will be given from the part related to the imaging and recording of object images.

  The camera system has an imaging system, an image processing system, a recording / reproducing system, and a control system. The imaging system has a photographing optical system 103 and an imaging element 106, and the image processing system has an A / D converter 130, an RGB image processing circuit 131, and a YC processing circuit 132. The recording / reproducing system includes a recording processing circuit 133 and a reproducing processing circuit 134, and the control system includes a camera system control circuit (control unit) 135, an operation detection circuit 136, and an image sensor driving circuit 137.

  Reference numeral 138 denotes a connection terminal that is connected to an external computer or the like and is standardized to transmit and receive data. The electric circuit described above is driven by receiving power from a small fuel cell (not shown).

  The imaging system is an optical processing system that forms an image of light from an object on the imaging surface of the imaging element 106 via the imaging optical system 103. By controlling the driving of a diaphragm (not shown) provided in the photographing optical system 103 and controlling the driving of the focal plane shutter 113 as necessary, the image sensor 106 receives an appropriate amount of object light. Can do.

  As the image sensor 106, an image sensor having a total of about 10 million pixels in which 3700 square pixels are arranged in the long side direction and 2800 in the short side direction is used. In addition, R (red), G (green), and B (blue) color filters are alternately arranged in each pixel to form a so-called Bayer array in which four pixels form a set.

  In the Bayer array, the overall image performance is improved by arranging more G pixels that are easily felt when an observer views the image than the R and B pixels. In general, in image processing using this type of image sensor, a luminance signal is generated mainly from G, and a color signal is generated from R, G, and B.

  The signal read from the image sensor 106 is supplied to the image processing system via the A / D converter 130. Image data is generated by image processing in this image processing system.

  The A / D converter 130 is a signal conversion circuit that converts, for example, an output signal of the image sensor 106 into a 10-bit digital signal and outputs the signal according to the amplitude of the signal read from each pixel of the image sensor 106. The subsequent image processing is executed by digital processing.

  The image processing system is a signal processing circuit that obtains an image signal in a desired format from R, G, and B digital signals. The R, G, and B color signals are converted into a luminance signal Y and a color difference signal (R−Y), ( B-Y) and the like are converted into a YC signal.

  The RGB image processing circuit 131 is a signal processing circuit that processes the output signal of the A / D converter 130, and includes a white balance circuit, a gamma correction circuit, and an interpolation calculation circuit that performs high resolution by interpolation calculation.

  The YC processing circuit 132 is a signal processing circuit that generates a luminance signal Y and color difference signals RY and BY. The YC processing circuit 132 generates a high-frequency luminance signal generation circuit that generates a high-frequency luminance signal YH, a low-frequency luminance signal generation circuit that generates a low-frequency luminance signal YL, and color difference signals RY and BY. It has a color difference signal generation circuit. The luminance signal Y is formed by combining the high frequency luminance signal YH and the low frequency luminance signal YL.

  The recording / reproducing system is a processing system that outputs an image signal to a memory (not shown) and outputs an image signal to the display unit 107. The recording processing circuit 133 performs writing processing and reading processing of the image signal to the memory, and the reproduction processing circuit 134 reproduces the image signal read from the memory and outputs it to the display unit 107.

  The recording processing circuit 133 includes a compression / expansion circuit that compresses the YC signal representing still image data and moving image data in a predetermined compression format and expands the compressed data. The compression / decompression circuit has a frame memory or the like for signal processing. The frame memory stores the YC signal from the image processing system for each frame, and the signals accumulated from each block among a plurality of blocks. Read and compression encode. The compression encoding is performed, for example, by subjecting the image signal for each block to two-dimensional orthogonal transformation, normalization, and Huffman encoding.

  The reproduction processing circuit 134 is a circuit that converts the luminance signal Y and the color difference signals RY and BY into a matrix signal, for example, an RGB signal. The signal converted by the reproduction processing circuit 134 is output to the display unit 107 and displayed (reproduced) as a visible image. The reproduction processing circuit 134 and the display unit 107 may be connected via wireless communication such as Bluetooth. With such a configuration, an image captured by this camera can be monitored from a remote location.

  On the other hand, the operation detection circuit 136 in the control system detects the operation of the main switch 119, the release button 120, the finder mode changeover switch 123 and the like (other switches are not shown), and the detection result is sent to the camera system control circuit 135. Output.

  The camera system control circuit 135 receives the detection signal from the operation detection circuit 136 and performs an operation according to the detection result. Further, the camera system control circuit 135 generates a timing signal for performing an imaging operation and outputs the timing signal to the imaging element driving circuit 137.

  The image sensor drive circuit 137 receives the control signal from the camera system control circuit 135 and generates a drive signal for driving the image sensor 106. The information display circuit 142 receives a control signal from the camera system control circuit 135 and controls driving of the information display unit 180 in the optical viewfinder.

  The control system controls driving in the imaging system, image processing system, and recording / reproducing system in accordance with the operation of various switches provided in the camera body 101. For example, when SW2 is turned ON by operating the release button 120, the control system (camera system control circuit 135) performs driving of the image sensor 106, operation of the RGB image processing circuit 131, compression processing of the recording processing circuit 133, and the like. Control. Further, the control system controls the display of the information display unit 180 in the optical viewfinder via the information display circuit 142 to change the display in the optical viewfinder (display segment state).

  Next, the focus adjustment operation of the photographic optical system 103 will be described.

  The camera system control circuit 135 is connected to the AF control circuit 140. Further, by attaching the lens device 102 to the camera body 101, the camera system control circuit 135 is connected to the lens system control circuit 141 in the lens device 102 via the mount contacts 101a and 102a. The AF control circuit 140, the lens system control circuit 141, and the camera system control circuit 135 communicate data required for specific processing with each other.

  The focus detection unit 121 outputs a detection signal in a focus detection area provided at a predetermined position in the shooting screen to the AF control circuit 140. The AF control circuit 140 generates a focus detection signal based on the output signal from the focus detection unit 121, and detects the focus adjustment state (defocus amount) of the photographing optical system 103. Then, the AF control circuit 140 converts the detected defocus amount into a drive amount of a focus lens, which is a part of the photographing optical system 103, and sends information related to the focus lens drive amount via the camera system control circuit 135. To the lens system control circuit 141.

  Here, when the focus adjustment is performed on the moving object, the AF control circuit 140 takes into account the time lag from when the release button 120 is fully pressed until the actual imaging control is started. Predict an appropriate stop position. Then, information regarding the driving amount of the focus lens to the predicted stop position is transmitted to the lens system control circuit 141.

  On the other hand, when the camera system control circuit 135 determines that the brightness of the object is low and sufficient focus detection accuracy cannot be obtained based on the output signal of the image sensor 106, the flash light emitting unit 104 or the camera body 101 is provided. The object is illuminated by driving a white LED or a fluorescent tube (not shown).

  When the lens system control circuit 141 receives information on the drive amount of the focus lens from the camera system control circuit 135, the lens system control circuit 141 emits light for the drive amount by the drive mechanism (not shown) disposed in the lens device 102. Move in the direction of the axis L1. As a result, the photographing optical system 103 is brought into focus. As described above, when the focus lens is composed of a liquid lens or the like, the interface shape is changed.

  When the AF control circuit 140 detects that the object is in focus, this information is transmitted to the camera system control circuit 135. At this time, if SW2 is turned on by a full press operation of the release button 120, the photographing operation is performed by the imaging system, the image processing system, and the recording / reproducing system as described above.

  1 to 5 are sectional views of the camera system in this embodiment. In these drawings, a part of the lens device 102 is shown. The same members as those described in FIG.

  Here, FIG. 1 is a cross-sectional view of the camera system in the second optical path division state, and FIG. 2 is a camera system in the middle of switching between the first optical path division state and the second optical path division state. FIG. FIG. 3 is a cross-sectional view of the camera system in the first optical path split state, and FIG. 4 is a cross-sectional view of the camera system in a state where the camera system is in the middle of switching between the first optical path split state and the third optical path split state. FIG. 5 is a cross-sectional view of the camera system in the third optical path division state.

  Hereinafter, the configuration of the camera system will be described with reference to FIG. 3 (FIG. 3) when the optical path splitting system constituted by the half mirror 111 and the sub mirror 122 is in the first optical path splitting state described above.

  In FIG. 3, 101 is a camera body, and 102 is a lens device. The lens device 102 is attached to the camera side mount 101b via the lens side mount 102b. Reference numeral 103a denotes a photographing lens positioned closest to the image plane among a plurality of lenses constituting the photographing optical system 103, and reference numeral 105 denotes a focusing screen of the finder optical system. Reference numeral 107 denotes a display unit, and 163 denotes an eyepiece shutter.

  Reference numeral 164 denotes a condenser lens that serves as a light beam capturing window in the focus detection unit 121, and reference numeral 165 denotes a reflecting mirror that reflects the light flux from the condenser lens 164. Reference numeral 166 denotes a re-imaging lens for imaging the light beam reflected by the reflection mirror 165 on the focus detection sensor 167, and 167 denotes a focus detection sensor.

  Reference numeral 111 denotes a movable half mirror, which is held by a half mirror receiving plate (not shown). Pins 173 are provided on both side edge portions (backward direction and front side of the paper surface) of the half mirror receiving plate, and pins 174 are provided on one side edge portion (backward direction on the paper surface). Here, the half mirror 111 and the pins 173 and 174 move integrally.

  Reference numeral 170 denotes a half mirror drive lever, and 171 denotes a half mirror support arm. The half mirror drive lever 170 is rotatably supported with respect to a rotation shaft 170 a fixed to the camera body 101, and the half mirror support arm 171 is supported to be rotatable with respect to a rotation shaft 171 a fixed to the camera body 101. ing.

  Further, the half mirror support arm 171 is connected to a structure having substantially the same shape provided on the opposite wall surface side of the mirror box via the connection portion 171b. Pins 173 provided on both sides of a half mirror receiving plate (not shown) are engaged with a through-hole portion 171 c provided at the tip of the half mirror support arm 171. Thereby, the half mirror 111 can be rotated centering on the through-hole part 171c via the half mirror receiving plate.

  The half mirror backing plate is biased in the direction of arrow A by a torsion spring (not shown) at an intermediate position between the pins 173 and 174, and the biasing force of the torsion spring is also applied to the half mirror 111 via the half mirror backing plate. is working.

  In the first optical path split state, the mirror stoppers 160 and 161 are in a state where they enter the moving area of the half mirror 111, so that the half mirror 111 receives the urging force of the torsion spring and hits the mirror stoppers 160 and 161. It touches. At this time, there is a slight gap between the pin 173 and the first cam surface 170b of the half mirror drive lever 170 and between the pin 174 and the second cam surface 170c of the half mirror drive lever 170. Thereby, the half mirror 111 is positioned in the state shown in FIG.

  The mirror stoppers 160 and 161 can enter or retreat into the moving area of the half mirror 111 by driving the mirror driving mechanism. In addition, the mirror stoppers 160 and 161 are located outside the photographing optical path (positions that do not affect the photographing light flux) regardless of whether the mirror stoppers 160 and 161 are inside or outside the moving region of the half mirror 111. Further, mirror stoppers 175 and 176, which will be described later, are similarly located outside the photographing optical path.

  On the other hand, the sub mirror 122 is rotatable about the rotation axis 125. In the first optical path split state, the transmitted light from the half mirror 111 is transmitted to the focus detection unit 121 (condenser lens 164) side as shown in FIG. It is held at the position where it is reflected.

  In the first optical path division state, a part of the light beam from the photographing optical system 103 is reflected by the half mirror 111 and guided to the finder optical system, and the remaining light beam is transmitted through the half mirror 111 and reflected by the sub mirror 122. Then, it is guided to the focus detection unit 121.

  When the mirror stoppers 160 and 161 in the state shown in FIG. 3 are retracted from the moving area of the half mirror 111, the half mirror 111 receives the urging force in the direction of arrow A by a torsion spring (not shown) and enters the state shown in FIG. . At this time, the pin 173 contacts the first cam surface 170b of the half mirror drive lever 170 and the pin 174 contacts the second cam surface 170c of the half mirror drive lever 170 by the biasing force of the torsion spring.

  And according to rotation of the half mirror drive lever 170, the pins 173 and 174 slide along the first cam surface 170b and the second cam surface 170c, respectively, and the posture of the half mirror 111 changes. That is, the half mirror support arm 171 rotates with the rotation of the half mirror drive lever 170 and is connected to the half mirror drive lever 170 and the half mirror support arm 171 via the pins 173 and 174. The mirror receiving plate and the half mirror 111 operate integrally.

  As the half mirror drive lever 170 and the half mirror support arm 171 rotate counterclockwise in FIG. 3, the half mirror 111 contacts the mirror stoppers 175 and 176 as shown in FIG. At this time, since the half mirror 111 receives a biasing force in the direction of arrow A by a torsion spring (not shown), the half mirror 111 is held in the state shown in FIG. 1, that is, the second optical path split state.

  Here, when the half mirror 111 shifts from the first optical path split state to the second optical path split state, the sub mirror 122 rotates clockwise about the rotation shaft 125 to the lower part of the mirror box. Moving. That is, before the half mirror 111 shifts from the first optical path split state to the second optical path split state, the sub mirror 122 moves to the lower part of the mirror box to avoid the half mirror 111 from colliding with the sub mirror 122. ing.

  In the second optical path division state, as shown in FIG. 1, a part of the light flux from the photographing lens 103a is reflected by the half mirror 111 and guided to the focus detection unit 121, and the remaining light flux is half mirror 111. , And reaches the image sensor 106.

  On the other hand, when shifting from the first optical path split state (FIG. 3) to the third optical path split state (FIG. 5), the half mirror 111 is caused by the half mirror drive lever 170 rotating clockwise in FIG. Is retracted above the camera body 101 (to the focusing screen 105 side) with respect to the imaging optical path. Further, by rotating the sub mirror 122 in the clockwise direction in FIG. 3 about the rotation axis 125, the sub mirror 122 is retracted to the lower side of the camera body 101 with respect to the photographing optical path.

  In the third optical path division state, the light beam from the photographing lens 103a reaches the image sensor 106 as shown in FIG.

  Next, the operation of the camera system of this embodiment will be described with reference to FIG.

  If it is detected in step S1 that the main switch 119 is turned on, the electric circuit of the camera is activated in step S2.

  In step S3, the finder mode set by the finder mode changeover switch 123 is detected, and if it is the OVF mode, the process proceeds to step S13, and if it is not the OVF mode but the EVF mode, the process proceeds to step S4.

  In the OVF mode, the half mirror 111 and the sub mirror 122 are in the first optical path division state (FIG. 3).

  In the EVF mode, since no object light is guided to the finder optical system, the eyepiece shutter 163 is closed in step S4. In other words, the camera system control circuit 135 causes the eyepiece shutter 163 to enter the optical path of the finder optical system by controlling the driving of an eyepiece shutter driving circuit (not shown).

  This is to prevent the user from misunderstanding that the object image cannot be observed through the finder optical system, and that the light outside the camera enters the camera body 101 from the eyepiece of the finder optical system, and the imaging element. This is to prevent the occurrence of a ghost by reaching 106.

  In step S5, the display in the finder visual field by the information display unit 180 in the optical finder is set to a non-display state by controlling the driving of the information display circuit 142. Here, since the eyepiece shutter 163 has already been closed by the process in step S4, even if specific information is displayed in the viewfinder field, the photographer cannot see the information. Therefore, by stopping driving of the information display unit 180 in the optical viewfinder, unnecessary power consumption in the camera system can be suppressed, and battery consumption can be suppressed.

  In step S6, in order to move the half mirror 111 to the second optical path split state, first, the sub mirror 122 is moved to the lower part of the mirror box and retracted from the photographing optical path.

  In step S <b> 7, the mirror stoppers 160 and 161 are retracted from the moving region of the half mirror 111 by controlling the drive of the mirror drive control circuit 145. After retracting the mirror stoppers 160 and 161, when the half mirror driving lever 170 is rotated counterclockwise in FIG. By being received, it is driven to the second optical path division state (FIG. 1) through the state shown in FIG.

  As a result, a part of the light beam emitted from the photographing lens 103a is reflected by the half mirror 111 and guided to the focus detection unit 121, and the remaining light beam passes through the half mirror 111 and proceeds to the image plane side. .

  In the second optical path split state (FIG. 1), between the pin 173 and the first cam surface 170b of the half mirror drive lever 170 and between the pin 174 and the second cam surface 170c of the half mirror drive lever 170. There is a slight gap, and the half mirror 111 is positioned in contact with the mirror stopper 175 and the mirror stopper 176.

  The position of the reflection surface of the half mirror 111 in the second optical path division state is substantially equal to the position of the reflection surface of the sub mirror 122 in the first optical path division state. With this configuration, it is possible to prevent the position of the light beam incident on the focus detection unit 121 from being shifted between the first optical path split state and the second optical path split state.

  In the second optical path division state, the light beam from the photographing lens 103 a passes through the half mirror 111 and reaches the image sensor 106, so that the focus position of the object image formed on the image sensor 106 by the light beam transmitted through the half mirror 111 is reached. Is slightly different from the case of reaching the image sensor 106 without passing through the half mirror 111.

  For this reason, in step S9, the focus correction mode is activated to correct the above-described shift in the focus position.

  In the present embodiment, the focus detection signal output from the focus detection unit 121 indicates a focus state when the light beam from the photographing lens 103a directly reaches the image sensor 106 in the third optical path split state. . On the other hand, when the focus correction mode is set in the second optical path split state, the focus state when the light beam from the photographing lens 103a passes through the half mirror 111 and reaches the image sensor 106 is shown. The focus detection signal is corrected. For this reason, the focus position of the focus lens in the photographing optical system 103 in the second optical path division state is shifted by the amount of correction of the focus detection signal with respect to the focus positions in the first and third optical path division states. It will be.

  Therefore, in the EVF mode, when the photographing operation is performed with SW2 turned on, that is, when the optical path division system is switched from the second optical path division state to the third optical path division state, the front curtain drive mechanism of the focal plane shutter 113 With the above charging, the position of the focus lens is corrected by the amount of deviation described above. That is, the focus lens is moved from the in-focus position in the second optical path division state to the in-focus position in the third optical path division state. Thereafter, the focal plane shutter 113 is opened for a predetermined time to perform an imaging operation by the imaging element 106.

  By configuring as described above, in the EVF mode (second optical path division state), a focused image can be confirmed on the display unit 107, and when shooting is performed in the third optical path division state. It is possible to obtain a photographed image that is in focus.

  In step S10, only the front curtain of the focal plane shutter 113 is caused to travel to the bulb exposure state so that the object light that has passed through the photographing optical system 103 continuously reaches the image sensor 106, and an image is displayed on the display unit 107. It is assumed that it is possible to capture an image for displaying.

  In step S11, the display unit 107 is powered on. In step S <b> 12, the image pickup operation by the image pickup device 106 is continuously performed on the object image formed by the photographing optical system 103, and the image data read from the image pickup device 106 and subjected to image processing is displayed on the display unit 107 in real time. Display. Then, the process proceeds from step S12 to step S20.

  If it is determined in step S3 that the OVF mode is set, the process proceeds to step S13, and the finder mode switching operation is not performed.

  In step S14, the camera system control circuit 135 determines whether or not the manual focus mode is set based on the operating state of an AF / MF selector switch (not shown) provided in the camera system. If the manual focus mode is set, the process proceeds to step S4. If the manual focus mode is not set and the auto focus mode is set, the process proceeds to step S16.

  When the manual focus mode is set, it is not necessary to operate the focus detection unit 121, and the background (subject image) can be more accurately grasped by using the EVF than by using the OVF. it can. Therefore, when the manual focus mode is set, the process proceeds to step S4 in order to perform real-time display on the display unit 107.

  In step S16, the camera system control circuit 135 drives the information display unit 180 in the optical viewfinder to display the information display in the viewfinder (lighted), and the process proceeds to step S20.

  In step S20, the camera system control circuit 135 determines whether or not the finder mode changeover switch 123 has been operated based on the output of the operation detection circuit 136. Here, when the finder mode changeover switch 123 is operated, the process proceeds to step S22 to switch the finder mode. The specific operation in step S22 is shown in FIG.

  On the other hand, if the finder mode changeover switch 123 has not been operated, the process proceeds to step S21 to determine the set finder mode. Here, in the case of setting to switch to the OVF mode, the flow proceeds to the flow shown in FIG. If the setting is to switch to the EVF mode, the flow proceeds to the flow shown in FIG.

  Next, the finder mode switching operation will be described with reference to FIG.

  While the electric circuit in the camera system is operating, the camera system control circuit 135 monitors the state of each switch provided in the camera body 101 via the operation detection circuit 136, and the finder mode changeover switch 123 When an operation is detected, the finder mode switching operation starts immediately.

  In step S100, the camera system control circuit 135 detects the finder mode that is currently set. When the finder mode changeover switch 123 is instructed to switch from the OVF mode to the EVF mode, the process proceeds to step S101. On the other hand, when switching from the EVF mode to the OVF mode is instructed, the process proceeds to step S111.

  First, the case of switching from the OVF mode to the EVF mode will be described. In the OVF mode, the half mirror 111 and the sub mirror 122 are in the first optical path division state (FIG. 3). In the EVF mode, since no object light is guided to the finder optical system, the eyepiece shutter 163 is closed in step S101. In other words, the camera system control circuit 135 causes the eyepiece shutter 163 to enter the optical path of the finder optical system by controlling the driving of an eyepiece shutter driving circuit (not shown).

  This is to prevent the user from misunderstanding that the object image cannot be observed through the finder optical system, and that the light outside the camera enters the camera body 101 from the eyepiece part of the finder optical system. This is to prevent the occurrence of a ghost by reaching 106.

  In step S102, the display in the finder visual field by the information display unit 180 in the optical finder is set to a non-display state by controlling the driving of the information display circuit 142. Thereby, unnecessary power consumption in the camera system can be suppressed.

  In step S103, in order to move the half mirror 111 to the second optical path split state, first, the sub mirror 122 is moved to the lower part of the mirror box and retracted from the photographing optical path.

  In step S <b> 104, the mirror stoppers 160 and 161 are retracted from the moving region of the half mirror 111 by controlling the drive of the mirror drive control circuit 145. After retracting the mirror stoppers 160 and 161, when the half mirror drive lever 170 is rotated counterclockwise in FIG. 3 in step S105, the half mirror 111 is biased by a spring (not shown) (force indicated by arrow A). By being received, it is driven to the second optical path division state (FIG. 1) through the state shown in FIG.

  As a result, a part of the light beam emitted from the photographing lens 103a is reflected by the half mirror 111 and guided to the focus detection unit 121, and the remaining light beam passes through the half mirror 111 and proceeds to the image plane side. .

  In step S106, a focus correction mode is activated to correct the above-described shift in the focus position.

  In step S107, only the front curtain of the focal plane shutter 113 is caused to travel to the bulb exposure state so that the object light that has passed through the photographing optical system 103 reaches the image sensor 106 continuously, and an image is displayed on the display unit 107. It is assumed that it is possible to capture an image for displaying.

  In step S108, the display unit 107 is powered on. In step S <b> 109, an image pickup operation by the image pickup device 106 is continuously performed on the object image formed by the photographing optical system 103, and image data read from the image pickup device 106 and subjected to image processing is displayed on the display unit 107 in real time. Display. Then, the switching operation from the OVF mode to the EVF mode is completed.

  Here, in the second optical path division state that is the EVF mode, the light beam from the photographing lens 103 a reaches the image sensor 106 after being refracted by the half mirror 111. For this reason, as shown in FIG. 15, the light receiving area 190 of the image sensor 106 in the second optical path split state is in the vertical direction of the image sensor 106 with respect to the light receiving area 191 of the image sensor 106 in the third optical path split state ( There may be a slight deviation in the vertical direction in FIG. That is, an image displayed in real time on the display unit 107 in the second optical path division state may be shifted without matching with an image photographed in the third optical path division state.

  Here, an area 190 a that does not overlap the area 191 in the area 190 is an area that is displayed in real time on the display unit 107 but is not included in an image obtained by imaging in the third optical path division state.

  In the camera of the present embodiment, as shown in FIG. 16, the region 192 corresponding to the region 190a (FIG. 15) is blacked out of the image region displayed in real time on the display unit 107, and the entire region 190 is not displayed. I am doing so. This process is performed in the reproduction processing circuit 134.

  As a result, it is possible to avoid a problem such that an image actually displayed on the display unit 107 is not included in the actually captured image.

  Next, a case where the process proceeds from step S100 to step S110 in order to switch from the EVF mode to the OVF mode will be described.

  In the EVF mode, the half mirror 111 and the sub mirror 122 are in the second optical path division state (FIG. 1), and real-time display is performed on the display unit 107.

  In step S110, the display state on the display unit 107 is changed to a blackout (fixed color display) state, or the update of the image is temporarily stopped in the real time display, and the image updated immediately before (the image in the freeze state) is displayed. It is left displayed on the unit 107. The display unit 107 is driven by a camera system control circuit 135.

  When switching from the EVF mode to the OVF mode, that is, when the half mirror 111 and the sub mirror 122 are operated from the second optical path split state to the first optical path split state, if the real time display is performed on the display unit 107, half The movement of the mirror 111 or the like blocks the light beam incident on the image sensor 106 from the photographing optical system 103, and the image displayed on the display unit 107 becomes unsightly.

  Therefore, in this embodiment, it is possible to prevent an unsightly image from being displayed on the display unit 107 by causing the display unit 107 to perform the display as described above.

  Note that the display unit 107 may be in a non-display state (off state).

  Further, in this embodiment, the display unit 107 is in a blackout state or a freeze state image is displayed, but other displays such as the half mirror 111 and the sub mirror 122 are being switched. The information shown may be displayed. Also in this case, the above-described effects can be obtained.

  In step S111, the driving of the display unit 107 is stopped and the imaging operation by the imaging element 106 is stopped. Thereby, unnecessary power consumption in the camera system can be suppressed.

  In step S112, the rear curtain of the focal plane shutter 113 is driven to close the shutter, and the driving mechanism for the front curtain and the rear curtain is charged in preparation for shooting. In step S113, the mirror stoppers 160 and 161 are retracted from the movement region of the half mirror 111 in order to enable the movement of the half mirror 111 performed in a later step.

  In step S114, the half mirror drive lever 170 is rotated clockwise in FIG. 1, and only the half mirror 111 is moved in the order of the state of FIG. 2, the state of FIG. 3, the state of FIG. 4, and the state of FIG. At this time, the half mirror 111 enters the third optical path division state (FIG. 5) through the first optical path division state (FIG. 3).

  In step S115, the mirror stoppers 160 and 161 are moved into the moving area of the half mirror 111 and moved to a predetermined position for positioning the half mirror 111.

  As described above, after the mirror stoppers 160 and 161 are retracted from the moving region of the half mirror 111, the half mirror 111 is moved to the third optical path split state, and then the mirror stoppers 160 and 161 are moved within the moving region of the half mirror 111. Therefore, the half mirror 111 does not collide with the mirror stoppers 160 and 161 when the half mirror 111 moves. Thereby, the mechanical reliability at the time of switching from the OVF mode to the EVF mode can be increased.

  In step S116, the half mirror drive lever 170 is rotated counterclockwise in FIG. 5, and the half mirror 111 is moved from the third optical path split state (FIG. 5) to the first optical path split state (FIG. 4). Move to FIG. Here, the half mirror 111 comes into contact with the mirror stoppers 160 and 161 by receiving a biasing force (a force indicated by an arrow A in FIG. 3) of a spring (not shown) in the mirror driving mechanism.

  In step S117, the eyepiece shutter 163 provided in the viewfinder optical system is opened.

  In step S118, the camera system control circuit 135 determines whether or not the manual focus mode is set based on the operating state of an AF / MF selector switch (not shown) provided in the camera system. If the manual focus mode is set, the process proceeds to step S104. If the manual focus mode is not set and the auto focus mode is set, the process proceeds to step S120.

  When the manual focus mode is set, it is not necessary to operate the focus detection unit 121, and the background (subject image) can be more accurately grasped by using the EVF than by using the OVF. it can. Therefore, when the manual focus mode is set, the process proceeds to step S104 in order to perform real-time display on the display unit 107. When the process proceeds from step S118 to step S104, the eyepiece shutter 163 is closed.

  In step S <b> 120, the sub mirror 122 is caused to enter the imaging optical path, and the object light transmitted through the half mirror 111 is set at a predetermined position that guides it to the focus detection unit 121. Here, during the processing from step S110 to step S118, the sub mirror 122 is in the position in the second optical path division state (FIG. 1), that is, the position retracted from the photographing optical path, and operates when the process proceeds to step S120. Will do.

  In step S121, the camera system control circuit 135 drives the information display unit 180 in the optical viewfinder so that the information display in the viewfinder is displayed (lighted). Then, the switching operation from the EVF mode to the OVF mode is completed.

  Next, a case where the photographing operation is performed from the EVF mode will be described with reference to FIG.

  In step S31, it is determined whether or not SW1 is on. If SW1 is on, the process proceeds to step S32. If SW1 is off, the process returns to step S20.

  In step S32, a photometric operation is started, and the camera system control circuit 135 determines an exposure value (aperture value and exposure time) based on the photometric result. Further, the focus adjustment operation is performed by driving the focus lens to the in-focus position based on the detection result of the focus detection unit.

  In step S <b> 33, the image pickup device 106 continuously performs object image pickup operations, and the display unit 107 starts real-time display. Thus, the photographer can determine the composition while confirming the subject image displayed on the display unit 107. Thereafter, the process proceeds to step S34.

  In step S34, it is determined whether or not SW2 is on. If SW2 is off, the process proceeds to step S35 to determine whether or not SW1 is on. When SW1 is on, the process returns to step S33, and when it is off, the process returns to step S20. That is, real-time display continues until SW2 is turned on. On the other hand, if SW2 is on in step S34, the process proceeds to step S36.

  In step S36, the camera system control circuit 135 determines whether or not there is an image storage buffer area capable of storing image data obtained by the shooting operation in the memory. If there is no area where new image data can be stored in the image storage buffer area of the memory, a specific warning is displayed in the viewfinder field by controlling the driving of the information display circuit 142 in step S37. . A warning may be given by voice or the like. After the process in step S37, the process proceeds to step S20.

  On the other hand, if there is an image storage buffer area capable of storing new image data in the memory in step S36, the process proceeds to step S38.

  In step S <b> 38, the display unit 107 displays a fixed-color blackout image that is not a subject image, or displays the image (freeze image) that was read last from the image sensor 106. In addition, the display unit 107 can also be made into a non-display state by stopping the drive of the display unit 107. FIG. Thereby, the power consumed by the display unit 107 can be reduced, and the power saving of the camera system can be achieved.

  In step S39, the rear curtain of the focal plane shutter 113 is driven to close the shutter, and the driving mechanism for the front curtain and the rear curtain is charged by a shutter charge mechanism (not shown) in preparation for shooting. Here, a shutter charge mechanism comprising an electromagnetic motor (not shown) and a gear train can be used to charge the front curtain of the focal plane shutter 113 that has opened the shutter opening and close the shutter opening. In this case, it is not necessary to charge the trailing curtain to the exposure preparation position at the time of charging, and the power consumption in driving the focal plane shutter 113 can be reduced.

  In step S40, the image pickup signal accumulated in the image pickup device 106 is read from the image pickup device 106, and the A / D converter 130, the RGB image processing circuit 131, the YC processing circuit 132, and the recording processing circuit 133 are processed with respect to the signal. Process. Then, the generated image data subjected to the above processing is written in a predetermined area of the memory. The details of the photographing operation in step S40 will be described later with reference to FIG.

  In step S41, by driving the shutter charge mechanism, the front curtain and rear curtain drive mechanisms of the focal plane shutter 113 are once charged to the exposure preparation position where the shutter opening is closed. Thereafter, only the front curtain of the focal plane shutter 113 is caused to travel to be in a bulb exposure state, and object light is continuously guided to the image sensor 116. Thereby, imaging for displaying an image on the display unit 107 is enabled.

  In step S42, the display unit 107 starts real-time display. If the display unit 107 is turned off in step 38, the display unit 107 is turned on. Thus, the photographer can determine the composition while viewing the subject image displayed on the display unit 107.

  In step S43, the camera system control circuit 135 reads a part of the image data written in a predetermined area of the memory, performs white balance integration calculation processing and optical black integration calculation processing necessary for performing development processing, The calculation result is stored in the internal memory of the camera system control circuit 135.

  The camera system control circuit 135 reads out the captured image data written in a predetermined area of the memory using a recording / playback system and, if necessary, an image processing system, and uses the calculation result stored in the internal memory to Various development processes including white balance processing, gamma conversion processing, and color conversion processing are performed.

  Further, in the development process, dark current noise or the like of the image sensor 106 is reduced by performing a subtraction process using the dark image data captured in the dark capture process (data read from the image sensor 106 in the non-exposure state). Dark correction calculation processing to cancel is also performed.

  In step S44, the camera system control circuit 135 reads the image data written in the predetermined area of the memory, and performs image compression processing according to the set mode by a compression / decompression circuit (not shown). Then, the compressed image data is written into the empty image portion of the image storage buffer area of the memory.

  In step S45, the camera system control circuit 135 reads out the image data stored in the image storage buffer area of the memory along with the execution of a series of shooting operations, and uses a memory card or a compact flash memory via an interface or connector (not shown). Recording processing for writing to a recording medium such as a (registered trademark) card is started.

  The recording process is executed on the image data every time new data is written in the empty image portion of the image storage buffer area of the memory.

  In step S46, the camera system control circuit 135 determines whether SW1 is on. If SW1 is on, the process returns to step S33. If SW1 is off, the process returns to step S20.

  Next, a photographing operation (step S40 in FIG. 9 or step S77 in FIG. 10) in the camera system of the present embodiment will be described with reference to FIG.

  In step S301, the camera system control circuit 135 controls the drive of the mirror drive control circuit 145 to cause the half mirror 111 and the sub mirror 122 to be in the second optical path division state (FIG. 1) or the first optical path division state (FIG. 3) to the third optical path division state (FIG. 5). Further, the camera system control circuit 135 transmits information regarding the aperture value to the lens system control circuit 141 in accordance with the photometric data stored in the internal memory.

  In step S302, the lens system control circuit 141 that has received information on the aperture value from the camera system control circuit 135 controls the driving of the aperture provided in the lens device 102 so that the aperture diameter corresponds to the aperture value. To do.

  In step S303, the camera system control circuit 135 clears the charge of the image sensor 106, and then starts charge accumulation in the image sensor 106 in step S304.

  In step S305, the camera system control circuit 135 drives the focal plane shutter 113 to the open state, and starts an exposure operation for the image sensor 106 in step S306.

  In step S307, the camera system control circuit 135 determines whether or not the flash light emitting unit 104 is caused to emit light based on the photometric result. If it is determined that the flash light emitting unit 104 needs to emit light, the process proceeds to step S308. If it is determined that it is not necessary to emit light, the process proceeds to step S309.

  In step S308, the camera system control circuit 135 controls the drive of the flash light emitting unit 104 to irradiate the subject with illumination light.

  In step S309, the camera system control circuit 135 determines whether the previously determined exposure time has elapsed. If the predetermined exposure time has elapsed, the process proceeds to step S310.

  In step S <b> 310, the camera system control circuit 135 ends the exposure to the image sensor 106 by controlling the focal plane shutter 113 to be closed.

  In step S311, the camera system control circuit 135 instructs the lens system control circuit 141 to drive the aperture to the full aperture value. As a result, the lens system control circuit 141 controls the driving of the diaphragm so as to obtain the full aperture value. In step S312, the driving of the mirror drive control circuit 145 is controlled to return the half mirror 111 and the sub mirror 122 in the third optical path division state to the state before photographing. That is, when the EVF mode is set before photographing, the half mirror 111 and the sub mirror 122 are operated from the third optical path division state to the second optical path division state. Further, when the OVF mode is set before photographing, the half mirror 111 and the sub mirror 122 are operated from the third optical path division state to the first optical path division state.

  In step S313, it is determined whether or not the set charge accumulation time has elapsed. If the time has elapsed, the camera system control circuit 135 ends the charge accumulation process in the image sensor 106 in step S314. .

  In step S315, the charge signal accumulated from the image sensor 106 is read, and the read signal is processed by the A / D converter 130, the RGB image processing circuit 131, the YC processing circuit 132, and the recording processing circuit 133. Do. Then, the photographed image data generated by the above process is written in a predetermined area of the memory. When the series of processes described above is completed, the photographing process routine is terminated.

  Next, a case where a shooting operation is performed from the OVF mode will be described with reference to FIG.

  In step S71, it is determined whether or not SW1 is on. If SW1 is on, the process proceeds to step S72, and if SW1 is off, the process returns to step S20.

  In step S72, a photometric operation is started, and the camera system control circuit 135 determines an exposure value (aperture value and exposure time) based on the photometric result. Further, the focus adjustment operation is performed by driving the focus lens to the in-focus position based on the detection result of the focus detection unit.

  In step S73, it is determined whether or not SW2 is on. If SW2 is off, the process proceeds to step S74 to determine whether or not SW1 is on. When SW1 is on, the process returns to step S73. When SW1 is off, the process returns to step S20. On the other hand, if SW2 is on in step S73, the process proceeds to step S75.

  In step S75, the camera system control circuit 135 determines whether there is an image storage buffer area in the memory that can store image data obtained by the shooting operation. If there is no area where new image data can be stored in the image storage buffer area of the memory, a specific warning is displayed in the viewfinder field by controlling the driving of the information display circuit 142 in step S76. . A warning may be given by voice or the like. After the process in step S76, the process proceeds to step S20.

  On the other hand, if it is determined in step S75 that there is an image storage buffer area capable of storing new image data in the memory, the process proceeds to step S77.

  In step S77, the above-described photographing operation is performed. That is, the image pickup signal accumulated in the image pickup device 106 is read from the image pickup device 106, and the signal is processed by the A / D converter 130, the RGB image processing circuit 131, the YC processing circuit 132, and the recording processing circuit 133. Do. Then, the generated image data subjected to the above processing is written in a predetermined area of the memory.

  In step S78, the camera system control circuit 135 reads a part of the image data written in the predetermined area of the memory, performs white balance integration calculation processing and optical black integration calculation processing necessary for performing development processing, The calculation result is stored in the internal memory of the camera system control circuit 135.

  The camera system control circuit 135 reads out the captured image data written in a predetermined area of the memory using a recording / playback system and, if necessary, an image processing system, and uses the calculation result stored in the internal memory to Various development processes including white balance processing, gamma conversion processing, and color conversion processing are performed.

  Further, in the development process, dark current noise or the like of the image sensor 106 is reduced by performing a subtraction process using the dark image data captured in the dark capture process (data read from the image sensor 106 in the non-exposure state). Dark correction calculation processing to cancel is also performed.

  In step S79, the camera system control circuit 135 reads the image data written in the predetermined area of the memory, and performs image compression processing according to the set mode by a compression / decompression circuit (not shown). Then, the compressed image data is written into the empty image portion of the image storage buffer area of the memory.

  In step S80, along with the execution of a series of shooting operations, the camera system control circuit 135 reads the image data stored in the image storage buffer area of the memory, and uses a memory card or compact flash memory via an interface or connector (not shown). Recording processing for writing to a recording medium such as a (registered trademark) card is started.

  The recording process is executed on the image data every time new data is written in the empty image portion of the image storage buffer area of the memory.

  In step S81, the camera system control circuit 135 determines whether SW1 is on. If SW1 is on, the process returns to S73. If SW1 is off, the process returns to step S20.

  Next, signal processing for focus detection in the focus detection unit 121 will be described.

  The light beam (object light) emitted from the photographic lens 103a is reflected by the half mirror 111 in the second optical path division state, and reflected by the sub mirror 122 in the first optical path division state, and then a condenser provided below the mirror box. The light enters the lens 164. The light beam incident on the condenser lens 164 is deflected by the reflection mirror 165 and forms a secondary image of the object on the focus detection sensor 167 by the action of the re-imaging lens 166.

  The focus detection sensor 167 includes at least two pixel columns. When the signal waveforms output from the two pixel columns are compared, a relatively laterally shifted state is observed according to the imaging state of the object image formed by the photographing optical system 103 on the focus detection region. . The focus state is based on whether the imaging state is the front pin or the rear pin, and the shift direction of the output signal waveform is reversed, and the shift direction and shift amount (phase difference) are detected using a method such as correlation calculation. It is.

  FIGS. 13 and 14 are diagrams showing output signal waveforms of the focus detection sensor 167 input to the AF control circuit 140. FIG. The horizontal axis indicates the arrangement of pixels, and the vertical axis indicates the output value of the focus detection sensor 167. FIG. 13 shows an output signal waveform when the object image is not in focus, and FIG. 14 shows an output signal waveform when the object image is in focus.

  In general, the light beam used for focus detection is not the same as the imaging light beam in the fully open state, but is a part of the imaging light beam. That is, when performing focus detection, a dark F-number light beam is used. Further, in consideration of the error of the mechanism in the camera, the position of the image sensor 106 and the position of the focus detection sensor 167 are not optically conjugate in a strict sense.

  For this reason, even if the object image is in focus, a slight initial phase difference Δ remains between the two output signal waveforms as shown in FIG. The initial phase difference Δ is different from that used in the correction for the focus detection signal in the above-described focus correction mode (see step S106 in FIG. 11).

  Here, since the true phase difference can be obtained by subtracting the initial phase difference Δ from the phase difference detected by the correlation calculation of the two images, the presence of the initial phase difference Δ is not usually a problem.

  In the present embodiment, as described above, the light beam used for focus detection may be guided from the sub mirror 122 in the first optical path split state or may be guided from the half mirror 111 in the second optical path split state. In this case, the reflection surface position of the sub-mirror 122 in the first optical path division state (FIG. 3) and the reflection surface position of the half mirror 111 in the second optical path division state (FIG. 1) are completely in terms of mechanism accuracy. The values of the initial phase difference Δ differ depending on the optical path division state. For this reason, the true phase difference in the first and second optical path division states cannot be known only by subtracting a certain initial phase difference Δ from the phase difference detected by the correlation calculation.

  With normal component processing accuracy, there is a possibility that the positions of the two reflecting surfaces are shifted by approximately 30 μm in the direction perpendicular to the reflecting surfaces. Here, if it is attempted to mechanically reduce the displacement of the reflecting surface position, the cost for processing the parts becomes extremely high.

  Therefore, in the present embodiment, the initial phase difference Δ is set for each of the first optical path split state and the second optical path split state, and the initial phase difference Δ corresponding to the optical path split state is used, whereby the focus detection sensor 167 The output signal is corrected. As a result, the true phase difference according to the optical path division state can be known, and accurate focus detection can be performed based on the phase difference.

  As described above, it is possible to determine whether or not the photographing optical system is in a focused state by determining the identity of a set of signals in consideration of the initial phase difference. Further, the defocus amount can be obtained by detecting a phase difference using a known method using correlation calculation, for example, a method disclosed in Japanese Patent Publication No. 5-88445. Then, the obtained defocus amount is converted into the drive amount of the focus lens of the photographing optical system 103, and the focus lens is driven by the drive amount, the focus adjustment of the photographing optical system can be automatically performed.

  In the phase difference detection method, since the driving amount of the focus lens can be known in advance, the lens driving to the in-focus position is usually performed only once, and extremely fast focus adjustment is possible.

  According to the present embodiment, in addition to the case of observing an object image using a finder optical system (in the case of OVF mode), the focus is applied to the case where the object image is displayed on the display unit 107 in real time (in the case of EVF mode). The detection unit 121 can perform focus detection by the phase difference detection method, and can perform the focus adjustment operation of the photographing optical system at high speed. Further, if continuous shooting or moving image shooting is performed in the second optical path division state (FIG. 1), high-speed focus adjustment operation can be performed in these shootings. Further, since it is not necessary to provide two focus detection units as in the prior art, the camera system does not increase in size or increase in cost.

  Next, a camera system that is Embodiment 2 of the present invention will be described.

  In the first embodiment, the first optical path split state is directly shifted to the second optical path split state, and when the second optical path split state is shifted to the first optical path split state, the third optical path split state is The optical path is divided.

  On the other hand, in the present embodiment, when switching between the first optical path split state and the second optical path split state, the third optical path split state is passed, and this is different from the first embodiment. ing. Hereinafter, a different part from Example 1 is demonstrated. The same members as those described in the first embodiment will be described with the same reference numerals.

  FIG. 17 is a diagram for explaining the operation of the split optical system in the present embodiment. In the same figure, (A) is a first optical path split state, (C) is a third optical path split state, and (E) is a second optical path split state. (B) is a diagram in which the switching process between the first optical path split state and the third optical path split state is overwritten, and (D) is a switch between the third optical path split state and the second optical path split state. It is the figure which overwritten the substitution process.

  In these drawings, L2 is an optical axis of the photographing optical system 103, 106 is an image sensor, 211 is a movable half mirror, 222 is a sub mirror, and 201 is a light shielding plate. Reference numeral 202 denotes a mirror stopper, which holds the half mirror 211 in the first optical path division state by contacting the half mirror 211. Reference numeral 203 denotes a mirror stopper, which holds the half mirror 211 in the second optical path division state by coming into contact with the half mirror 211. Unlike the first embodiment, these mirror stoppers 202 and 203 are fixed in the camera body.

  A dotted line in FIG. 17 indicates an optical path through which the light beam from the photographing optical system 103 can travel in the camera system of the present embodiment, and each optical path division in FIGS. 17A, 17 </ b> C, and 17 </ b> E. The direction in which the light beam actually travels in the state is indicated by an arrow.

  In the first optical path division state shown in FIG. 17A, the half mirror 211 is obliquely arranged on the optical axis L2, and is positioned by abutting against the mirror stopper 202 by receiving a biasing force of a spring (not shown). ing. Further, a sub mirror 222 is located behind the half mirror 211 (on the image plane side).

  The first optical path division state is a state when the camera system is set to the OVF mode as in the first embodiment, and an object image can be observed through the finder optical system, and the focus detection unit 121. The focus adjustment state can be detected by the phase difference detection method.

  A part of the light beam incident on the half mirror 211 along the optical axis L2 from the photographing optical system 103 is reflected on the surface of the half mirror 211 upward (in the drawing) and guided to the finder optical system (focusing screen 105). It is burned. Further, the remaining light beam is transmitted through the half mirror 211, reflected by the sub mirror 222 located behind the half mirror 211 to the lower side of the camera (downward in the figure), and guided to the focus detection unit 121.

  In the third optical path split state shown in FIG. 17C, the half mirror 211 and the sub mirror 222 are positioned above the camera and are retracted from the photographing optical path. At this time, the light shielding plate 201 covers a region of the half mirror 211 that does not overlap with the sub mirror 222, and shields back incident light from the finder optical system together with the sub mirror 222. Thereby, it is possible to prevent back-incident light from the finder optical system from entering the image sensor 106 and to prevent ghost from occurring.

  In the second optical path split state shown in FIG. 17E, the half mirror 211 is obliquely arranged on the optical axis L2, and is positioned by abutting against the mirror stopper 203 by receiving a biasing force of a spring (not shown). ing. On the other hand, the sub mirror 222 is located above the camera together with the light shielding plate 201 and is retracted from the photographing optical path.

  The second optical path division state is a state when the camera system is set to the EVF mode as in the first embodiment, and an object image can be observed through the display unit 107 and the focus detection unit 121. The focus adjustment state can be detected by the phase difference detection method.

  A part of the light beam incident on the half mirror 211 from the photographing optical system 103 is reflected downward by the half mirror 211 and guided to the focus detection unit 121. Further, the remaining light flux passes through the half mirror 211 and enters the image sensor 106.

  The transition operation from the first optical path division state (A) to the third optical path division state (C) is almost the same as the mirror up operation of a general single-lens reflex camera as shown in FIG. That is, the half mirror 211 rotates so that the surface (reflection surface) faces upward of the camera, and the sub mirror 222 rotates so that the reflection surface faces upward of the camera. At this time, the sub mirror 222 moves to a position along the back surface of the half mirror 211.

  Note that the transition operation from the third optical path split state (C) to the first optical path split state (A) is the reverse of the above-described operation. In addition, the operations of the half mirror 211 and the sub mirror 222 described above are performed by, for example, transmitting the driving force of the motor to the cam via the gear train and rotating the cam, thereby causing the half mirror 211 and the sub mirror 222 engaged with the cam to rotate. This can be done by moving the pin.

  On the other hand, in the transition operation from the third optical path split state (C) to the second optical path split state (E), the half mirror 211 disposed substantially parallel to the optical axis L2 is a rear end portion of the half mirror 211, That is, it starts to fall from the side close to the image sensor 106 and comes into contact with the mirror stopper 203. At this time, the back surface of the half mirror 211 faces the photographing optical system 103 side.

  The position of the half mirror 211 substantially coincides with the position of the sub mirror 222 in the first optical path division state. In the present embodiment, unlike the first embodiment, the reflecting surface of the half mirror 211 is positioned on the image sensor 106 side, so that the optical axis after deflection by the half mirror 211 is the focus detection unit in the first optical path division state. The position of the half mirror 211 is determined so as to coincide with the optical axis incident on 121.

  With this configuration, the position of the focus detection region can be hardly changed between the first optical path division state and the second optical path division state.

  In the present embodiment, when switching between the first optical path split state and the second optical path split state, the states shown in FIGS. 17B to 17D are passed, so the mirror stoppers 202 and 203 are used in the embodiment. As in 1, it is not necessary to be movable (a structure that moves forward and backward with respect to the moving region of the half mirror). In addition, since the operations of the half mirror 211 and the sub mirror 222 are not hindered by the mirror stoppers 202 and 203, mechanical reliability is ensured when switching between the first optical path split state and the second optical path split state. can do.

  According to the camera of the present embodiment, even when electronic image display of an object image is performed on the display unit 107 in the second optical path division state, the focus adjustment state by the phase difference detection method is the same as in the first optical path division state. Therefore, a high-speed focus adjustment operation (focusing lens focusing drive) can be performed. Further, by performing continuous shooting or moving image shooting in the second optical path division state, high-speed focus adjustment operation is possible. In addition, since it is not necessary to provide the focus detection unit in each of the lens device and the camera body as in the above-mentioned document 4, the camera can be reduced in size and the cost is not increased.

  In the first and second embodiments, a camera that obtains a color image is taken as an example. However, the present invention is not limited to this, and the present invention is not limited to this. Applicable.

Sectional drawing of the camera system in a 2nd optical path division | segmentation state. Sectional drawing of the camera system in the middle of switching from the 1st optical path division state to the 2nd optical path division state. Sectional drawing of the camera system in a 1st optical path division | segmentation state. Sectional drawing of the camera system in the middle of switching from the 1st optical path division state to the 3rd optical path division state. Sectional drawing of the camera system in a 3rd optical path division | segmentation state. 1 is a schematic diagram illustrating a configuration of a camera system according to Embodiment 1. FIG. 1 is a block diagram illustrating a circuit configuration of a camera system according to Embodiment 1. FIG. 6 is a flowchart illustrating the operation of the camera system according to the first embodiment. 6 is a flowchart illustrating the operation of the camera system according to the first embodiment. 6 is a flowchart illustrating the operation of the camera system according to the first embodiment. 7 is a flowchart showing a finder mode switching operation. 6 is a flowchart illustrating a shooting operation in the camera system according to the first exemplary embodiment. The figure showing the output signal waveform of a focus detection sensor when an imaging optical system is not in focus. The figure showing the output signal waveform of a focus detection sensor when an imaging optical system is in an in-focus state. The figure showing the relationship between the image range which can be output to a display unit, and an imaging range. The figure showing the relationship between the image range which can be output to a display unit, and an imaging range. It is a figure for demonstrating the operation | movement of the optical path splitting system in Example 2 (AE).

Explanation of symbols

105 ... Focusing screen 106 ... Image sensor 107 ... Display unit 109 ... Viewfinder lens 111 ... Half mirror 121 ... Focus detection unit 122 ... Sub mirror 123 ... Viewfinder mode switch 135... Camera system control circuit 211... Half mirror 222... Sub mirror 201.

Claims (8)

An image sensor that photoelectrically converts a subject image formed by a light beam from a photographing lens;
A viewfinder optical system that enables observation of a subject image using the luminous flux;
A mirror unit that is driven to switch between a first state in which the light beam is reflected toward the finder optical system and a second state in which the light beam reaches the imaging element;
Display means for displaying an image generated using the output of the image sensor;
Control means for controlling the drive of the display means,
The control device causes the display device to display specific information before the mirror unit is driven to switch from the second state to the first state. An image sensor that photoelectrically converts a subject image formed by a light beam from a photographing lens;
A viewfinder optical system that enables observation of a subject image using the luminous flux;
A mirror unit that is driven to switch between a first state in which the light beam is reflected toward the finder optical system and a second state in which the light beam reaches the imaging element;
Display means for displaying an image generated using the output of the image sensor;
Control means for controlling the drive of the display means,
The control unit stops driving of the display unit before the mirror unit is driven to switch from the second state to the first state. A focus detection unit that detects a focus state of the photographing lens using the light beam;
The first state is a state in which the light beam is reflected toward the finder optical system and the focus detection means, and the second state is a state in which the light beam is transmitted toward the image sensor and the focus detection is performed. The imaging apparatus according to claim 1, wherein the imaging apparatus is in a transmitting / reflecting state reflecting toward the means and in a retracted state in which the imaging lens is retracted from the imaging optical path to the imaging element. An image sensor that photoelectrically converts a subject image formed by a light beam from a photographing lens;
A viewfinder optical system that enables observation of a subject image using the luminous flux;
Focus detection means for detecting a focus state of the photographing lens using the light flux;
A first state in which the light beam is reflected toward the finder optical system and the focus detection unit; and a transmission / reflection state in which the light beam is transmitted toward the imaging element and reflected toward the focus detection unit; A mirror unit that is driven to be switched to a retracted state of retracting from a photographing optical path from the photographing lens to the imaging element;
Display means for displaying an image generated using the output of the image sensor;
Control means for controlling the drive of the display means,
The control means causes the display means to display specific information before the mirror unit is driven to switch from the transmission / reflection state to the retracted state, and is driven to switch from the retracted state to the transmission / reflection state. An image pickup apparatus that displays the image on the display means later. The mirror unit includes a first mirror member that reflects a part of the light beam and transmits the remainder, and a second mirror member that reflects the light beam transmitted through the first mirror member,
In the first state, the first and second mirror members are disposed in the photographing optical path. In the transmission / reflection state, the first mirror member is disposed in the photographing optical path and the second mirror member is disposed in the photographing optical path. The imaging apparatus according to claim 3 or 4, wherein a mirror member is retracted from the imaging optical path, and the first and second mirror members are retracted from the imaging optical path in the retracted state.   The imaging apparatus according to claim 1, wherein the specific information is still image data generated using an output of the imaging element.   The imaging apparatus according to claim 1, wherein the specific information is information regarding a specific color. An imaging device according to any one of claims 1 to 7,
An imaging system comprising an imaging lens attached to the imaging apparatus.

Images