JP4438052B2 - Imaging device - Google Patents

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. It is also possible to measure subject luminance using the output of the image sensor.

  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.

On the other hand, in a camera having mode selection means for selecting a shooting mode, when the macro shooting mode is selected by the mode selection means, the image display unit is set in a display state and an image display unit (EVF; Electronic View Finder) is used. Some cameras allow you to shoot while observing the subject image. Further, when a shooting mode other than the macro shooting mode is selected, the image display unit is set in a non-display state so that an image can be taken while observing a subject image using an optical viewfinder (OVF, Optical View Finder) ( For example, see Patent Document 5).
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) JP-A-10-336495 (paragraph numbers 0021 to 0023, etc.)

  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. That is, in Patent Document 3, it is impossible to achieve both improvement in image quality and speeding up of focusing control.

  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.

  On the other hand, when the camera proposed in Patent Document 5 is applied to a single-lens reflex camera, the following problems occur. If the shooting mode selection means is operated while the playback mode for playing back and displaying the recorded image is set, the viewfinder mode (EVF mode and OVF mode) will be switched. Here, when the playback mode is switched to the shooting mode, since the finder mode is different from the finder mode before switching to the playback mode, the photographer is confused.

Imaging apparatus of the present invention includes an imaging device for photoelectrically converting an object image formed by the light flux from the photographic lens, a finder optical system that enables observation of the subject image by using the light flux, the using the light flux Focus detection means for detecting the focus state of the photographic lens, a half mirror and a reflection mirror, guides the light beam reflected by the half mirror out of the light beam to the finder optical system, and transmits the light beam transmitted through the half mirror. A first state in which the light is reflected by the reflection mirror and led to the focus detection unit, and the reflection mirror is retracted from the photographing optical path from the first state, and the reflection position of the half mirror is changed from the first state. By doing so, the light beam reflected by the half mirror is guided to the focus detection means, and the light beam transmitted through the half mirror is Recording a mirror unit which can be switched to a second state to direct the image element, and controls the switching operation of the mirror unit, a first mode in which an image recording operation using the output from the image sensor is to have a control means for operating in a second mode for reproducing and displaying the image, wherein, when said second mode is set to prohibit the switching operation of the mirror unit It is characterized by that.

According to the present invention, by prohibiting the mirror unit switching operation when the second mode is set, the state of the mirror unit is changed to the first when the second mode is switched to the first mode. And the malfunction by having switched between the 2nd states can be prevented.

  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. 1 to 7. 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 100 denotes a camera body, and reference numeral 101 denotes a lens device that can be detached from the camera body 100. In the lens apparatus 101, a diaphragm 102 and a photographing optical system 103 are provided. The lens device 101 is electrically and mechanically connected to the camera body 100 via a known mount mechanism. Then, by attaching the lens device 101 having different focal lengths to the camera body 100, it is possible to obtain shooting screens having various angles of view.

  In the lens device 101, the focus lens, which is a part of the photographing optical system 103, is moved in the direction of the optical axis L1 via a driving 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 rear surface of the camera body 100 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 : second state ), the light beam from the photographing optical system 103 passes through the half mirror 111 and passes through the open focal plane shutter 113, and the image sensor 106. And is reflected by the half mirror 111 and guided to the focus detection unit 121. 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 focal plane shutter 113 is opened, so that the light flux 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. In this state, optical path division by the half mirror 111 and the sub mirror 122 is not actually performed, but in this embodiment, this state is referred to as a third optical path division state.

  The optical path splitting system is driven by a mirror driving mechanism 150 (see FIG. 7) 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 the first to third directions. It is possible to switch between the optical path split states. The drive control of the mirror drive mechanism 150 is performed by a camera system control circuit 135 described later.

  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.

  A movable flash light emitting unit 104 is movable between a storage position stored in the camera main body 100 and a light emission position protruding from the camera main body 100. 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 activating the camera body 100.

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). ( Image recording operation: 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 (operation means), which can be switched between the OVF mode and the EVF mode each time the switch is pressed. Reference numeral 127 denotes a shooting / playback mode switching switch between a playback mode (second mode) for playing back and displaying an image obtained by the shooting operation and a shooting mode (first mode) for performing the shooting operation. It is operated to switch between.

  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, the shooting / playback mode changeover switch 127, etc. (other switches are not shown), and detects this. The result is output to the camera system control circuit 135.

  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, the image processing system, and the recording / reproducing system in accordance with the operation of various switches provided in the camera body 100. 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 mounting the lens device 101 to the camera body 100, the camera system control circuit 135 is connected to the lens system control circuit 141 in the lens device 101 via the mount contacts 100a and 101a. 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 (focus detection sensor 167) 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 100 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 related to the drive amount of the focus lens from the camera system control circuit 135, the lens system control circuit 141 transmits the focus lens to the drive amount via the drive mechanism (not shown) disposed in the lens device 101. 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 lens system control circuit 141 receives information on the exposure value (aperture value) from the camera system control circuit 135, the lens system control circuit 141 controls the aperture drive mechanism (not shown) in the lens device 101 to control the aperture value. The diaphragm 102 is operated so as to have a diaphragm aperture diameter according to the above. As a result, an appropriate amount of object light can be directed to the image plane side.

  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 101 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, reference numeral 100 denotes a camera body, and 101 denotes a lens device. The lens device 101 is attached to the camera side mount 100b via the lens side mount 101b. 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 100, 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 100. 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.

  Note that the mirror stoppers 160 and 161 can enter or retreat into the moving region of the half mirror 111 by driving the mirror driving mechanism 150. 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 transitioning 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 100 (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 shaft 125, the sub mirror 122 is retracted to the lower side of the camera body 100 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.

  A shooting sequence in the camera system of the present embodiment will be described below.

  First, when the main switch 119 is turned on, an electric circuit in the camera system is activated. Then, the display unit 107 is operated or the information display unit 180 in the optical viewfinder is operated according to the set finder mode. That is, in the EVF mode, real-time display is performed by causing the display unit 107 to display images sequentially read from the image sensor 106. In the OVF mode, specific information is displayed in the viewfinder field. Here, when the finder mode switch 123 is operated, the finder mode is switched.

  Next, when SW1 is turned on, focus adjustment is performed by driving the focus lens of the photographing optical system 130 under the control of the AF control circuit 140 and the lens system control circuit 141. Also, subject brightness is measured (photometric). Here, in any viewfinder mode of the EVF mode and the OVF mode, since the light beam from the photographing optical system 103 is guided to the focus detection unit 121, high-speed focus adjustment by the phase difference detection method can be performed. .

  When SW2 is turned on, the mirror drive mechanism 150 is driven to place the optical path splitting system (half mirror 111 and sub mirror 122) in the third optical path splitting state (FIG. 5), and the object from the photographing optical system 103 The light reaches the image sensor 106. A signal read from the image sensor 106 is subjected to predetermined processing in the image processing system, and then recorded on a recording medium (not shown) or displayed on the display unit 107.

  Next, the finder mode switching operation in the camera system having the above-described configuration will be described.

  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 100 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. FIG. 8 is a flowchart for explaining the finder mode switching operation.

  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 100 from the eyepiece of the finder optical system, and the imaging device. 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. Here, since the eyepiece shutter 163 has already been closed by the processing in step S101, the photographer cannot see the information even if specific information is displayed in the viewfinder field of view. 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 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 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 S106, a focus correction mode is activated to correct the above-described shift of 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 division state. . In contrast, 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 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. 12, the light receiving area 190 of the image sensor 106 in the second optical path division state is in the vertical direction ( 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. 13, the area 192 corresponding to the area 190a (FIG. 12) is blacked out of the image area displayed in real time on the display unit 107, and the entire area 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 S111 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 S111, the driving of the display unit 107 is stopped and the imaging operation by the imaging element 106 is stopped.

  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 150.

  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 S119.

  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 119, 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 the focus light to the focus detection unit 121. Here, during the processing from step S111 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 S119. Will do.

  In step S120, 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.

  In this embodiment, when the captured image is displayed on the display unit 107, that is, in the EVF mode, the optical path division system having the half mirror 111 and the sub mirror 122 is in the second optical path division state (FIG. 1). The light beam from the photographic lens 103 a is guided to the focus detection unit 121. Thereby, even in the EVF mode, a high-speed focus adjustment operation can be performed based on the focus detection by the focus detection unit 121 using the phase difference detection method.

  Next, switching operation between the shooting mode and the playback mode by operating the shooting / playback mode switch 127 will be described with reference to FIG.

  The camera system control circuit 135 determines whether or not the photographing / playback mode switch 127 has been operated via the operation detection circuit 136. If the shooting / playback mode switch 127 is operated, it is determined in step S200 whether the finder mode currently set is the OVF mode. If the OVF mode is set, the process proceeds to step S210. If the EVF mode is set, the process proceeds to step S201.

  In step S210, by controlling the driving of the information display circuit 142, the information display in the viewfinder field by the information display unit 180 in the optical viewfinder is set to the non-display state (lights off). By stopping the display of the information display unit 180 in the optical finder and making the information display in the finder field of view non-display state, unnecessary power consumption can be suppressed and battery consumption can be suppressed.

  In step S201, information related to the finder mode determined in step S200 is stored in the memory 135a of the camera system control circuit 135.

  In step S202, image data recorded on a recording medium (not shown) is read via the recording processing circuit 133, and the read image data is processed by the reproduction processing circuit 134. Then, the image data processed by the reproduction processing circuit 134 is displayed on the display unit 107.

  In step S203, the input of the finder mode changeover switch 123 is invalidated and the setting according to the operation of the finder mode changeover switch 123 is prohibited. As a result, when the playback mode is set, it is possible to prevent the viewfinder mode from being switched by inadvertently operating the viewfinder mode switch 123.

  Specifically, when switching from playback mode to shooting mode, you can prevent the viewfinder mode from switching regardless of the user's intention, or a mode that is different from the viewfinder mode that the user has memorized. It can be prevented from being set to. Accordingly, the user is not confused when observing the subject image when the display unit 107 reproduces the recorded image and then switches to the photographing mode again. In the finder mode set before switching to the reproduction mode, operations such as composition determination can be performed smoothly.

  In step S204, the display unit 107 is in a standby state for input of a switch such as the release button 120 while displaying the recorded image.

  In step S <b> 205, the camera system control circuit 135 determines whether various switches such as the release button 120 have been operated via the operation detection circuit 136. If none of the switches are operated, the process returns to step S204. On the other hand, if there is an input from any of the switches, the process proceeds to step S206.

  In step S206, it is determined whether or not the operated switch is the shooting / playback mode switch 127. If the input is from the shooting / playback mode switch 127, the process proceeds to step S207. On the other hand, when the input is from another switch, for example, when the input is from an image deletion switch or a display image changeover switch (not shown), the process proceeds to step S220.

  In step S220, an operation corresponding to the input from the other switch is performed. For example, in the case of input from the image erasure switch, the image data is erased, and in the case of input from the display image changeover switch, the recorded image to be displayed on the display unit 107 is switched. When the process in step S220 is completed, the process returns to step S204 and enters an input standby state.

  In step S207, the playback mode is switched to the shooting mode, and the input of the finder mode changeover switch 123 prohibited in step S203 is validated. Thus, the user can freely switch the finder mode by operating the finder mode switching switch 123.

  In step S208, it is determined whether or not the finder mode stored in step S201 is the OVF mode. If the OVF mode is selected, the process proceeds to step S230. If the EVF mode is selected, the process proceeds to step S209.

  In step S230, by controlling the driving of the information display circuit 142, the information display in the viewfinder visual field by the information display unit 180 in the optical viewfinder is set to the display state (lit). In this embodiment, when the shooting mode is switched to the playback mode, the input of the finder mode switching switch 123 is invalidated. Therefore, when the playback mode is set, the finder mode is not switched and the half mirror 111 and the sub mirror 122 are switched. Is not performed.

  For this reason, when the OVF mode is set before switching to the playback mode, when the playback mode is switched to the shooting mode, the OVF mode is set simply by driving the information display unit 180 in the optical viewfinder.

  In step S209, real-time display on the display unit 107 is performed. As described above, when the shooting mode is switched to the reproduction mode, the half mirror 111 and the sub mirror 122 are not driven. Therefore, in the case where the EVF mode is set before switching to the playback mode, when switching from the playback mode to the shooting mode, real-time display can be performed simply by starting reading of an image with the image sensor 106.

  In the present embodiment, as described above, when the playback mode is set, the operation of the finder mode changeover switch 123 is invalidated. However, the present invention is not limited to this, and the half mirror 111 is set when the playback mode is set. The sub mirror 122 may be not driven. For example, when a switch other than the finder mode switch 123 is operated, the finder mode switching operation is performed in conjunction with an operation according to an instruction from the other switch. During this, the viewfinder mode can be prevented from being switched even when the other switches are operated.

  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.

  10 and 11 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. 10 shows an output signal waveform when the object image is not in focus, and FIG. 11 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.

  Therefore, even when 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. 8).

  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 in real time on the display unit 107 (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.

  In addition, since the operation of the finder mode changeover switch 123 is invalidated when the playback mode is set, the finder mode set in the shooting mode before switching to the playback mode when switching from the playback mode to the shooting mode. Can prevent switching to a different mode. Thereby, it is possible to prevent the user from being confused by switching the finder mode, and to smoothly perform operations such as composition determination in the finder mode set before switching to the reproduction mode.

  In the above-described embodiments, the camera system having the configuration in which the half mirror and the sub mirror are separately driven has been described. However, the present invention can also be applied to a camera system in which the half mirror and the sub mirror are integrally driven. That is, in the configuration in which the half mirror and the sub mirror are arranged in the photographing optical path in the OVF mode and retracted from the photographing optical path in the EVF mode, the half mirror and the sub mirror may not be driven when the reproduction mode is set.

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. 7 is a flowchart showing a finder mode switching operation. 7 is a flowchart showing an operation for switching between a shooting mode and a playback mode. 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.

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

Claims (1)

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;
Consists of a half mirror and a reflection mirror, of which the light beam reflected by the half mirror is guided to the finder optical system, and the light beam transmitted through the half mirror is reflected by the reflection mirror and guided to the focus detection means. From the first state and the first state, the reflection mirror is retracted out of the photographing optical path, and the reflection position of the half mirror is changed from the first state, so that it is reflected by the half mirror out of the light flux. A mirror unit capable of guiding the luminous flux to be performed to the focus detection means and switching to a second state in which the luminous flux transmitted through the half mirror is guided to the imaging device;
Control means for controlling the switching operation of the mirror unit and operating in a first mode in which an image recording operation is performed using an output from the image sensor and a second mode in which a recorded image is reproduced and displayed. And
The image pickup apparatus, wherein the control unit prohibits the switching operation of the mirror unit when the second mode is set.

Images