JP2010014950A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a user can not confirm intuitively what part of a subject is focused on when photographing if composition is changed after focusing lock. <P>SOLUTION: A first display area in which a subject image is observed as an optical image, and a second display area in which an electronic image displayed by a display means is observed by a display means, which can be simultaneously observed through an eyepiece window, are provided in a finder. Simultaneously with turning on a release button SW1, a focused image and focusing position information are acquired simply, and the focused image and the focusing position superposed on the focused image are displayed to be viewed in the second display area. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that captures an electronic image.

  2. Description of the Related Art Conventionally, there has been known a camera that can switch between an optical viewfinder and an electronic viewfinder as an imaging device that captures an electronic image, and facilitates a confirmation operation of a reproduced image without changing the shooting posture (see Patent Document 1). This camera has a first finder system that optically guides a subject image that has passed through a photographing lens to a finder, and a second finder system that electronically guides the subject image to a finder as a display device via an image sensor. The camera also has a finder switching unit that switches between the valid states of both finder systems. In addition, the camera includes a mode switching unit that switches between a recording mode that is recorded in the storage unit and a reproduction mode that is read from the storage unit and displayed on the display device, and a control unit that switches between these modes.

In this camera, when the control unit switches from the recording mode to the playback mode, the finder switching unit forcibly switches the finder system to the valid state of the second finder system. When the control unit switches back to the recording mode again, the finder switching unit automatically returns to the finder system that has been enabled in the original recording mode.
JP 2004-357123 A

  However, the conventional imaging device has the following problems. That is, in the camera described in Patent Document 1, when switching to the playback mode, the first viewfinder system that optically guides the subject image that has passed through the photographing lens to the viewfinder, and electronically guided to the viewfinder via the image sensor. The second finder system was simply switched. Therefore, when the second finder system is used, the subject image cannot be observed, and the occasional photo opportunity is often missed.

  Therefore, the present invention has been made in view of the above problems, and provides an imaging device that can simultaneously confirm a focused state of a subject and a subject image at that time without missing a photo opportunity. The purpose is to do.

  In order to achieve the above object, an image pickup apparatus of the present invention includes an image pickup element that photoelectrically converts a subject image formed by a photographing lens, a first display region in which the subject image is observed as an optical image, and display means. The second display area in which the electronic image photoelectrically converted by the image sensor displayed by the imaging device is observed can be photographed by the finder means capable of simultaneously observing through the eyepiece window, the photographing preparation instruction means, and the photographing preparation instruction means. The determination means for determining the in-focus state of the subject image after the preparation instruction is given, and the in-focus state by the determination means while the preparation instruction instruction is continuously given by the shooting preparation instruction means. And display means for superimposing information on the in-focus position on the image at the time of determination and displaying the information in the second display area.

  According to the imaging apparatus of the present invention, it is possible to check the state of the subject and the in-focus position when the focus is locked with an electronic image while allowing the optical image of the subject to be observed without taking the eyes off the viewfinder. is there. Therefore, even if the composition is changed after focusing, it is possible to intuitively visually recognize in which area of the subject the composition is focused, making it easy to set the composition, and realizing an imaging device that hardly misses a photo opportunity. it can.

  An embodiment of an imaging device of the present invention will be described with reference to the drawings. The imaging apparatus of this embodiment is applied to a digital single lens reflex camera.

[First Embodiment]
The digital single-lens reflex camera of this embodiment is a still camera that captures a subject image with an image sensor such as a CMOS or a CCD. In this digital single-lens reflex camera, a release button for instructing the start of an imaging operation is provided on the exterior housing of the camera. In addition, by continuously driving the image sensor, not only a still image but also a moving image can be captured. Further, this camera has a mode (live view mode) in which an image is captured by an image sensor at a predetermined frame rate (for example, 60 frames) and displayed on a liquid crystal display without pressing a release button as an imaging mode. . Here, not the liquid crystal display of the rear monitor but a liquid crystal display observable in the finder will be described. That is, the operation when the photographer is looking through the viewfinder in the live view mode will be described.

  FIG. 1 is a diagram illustrating a schematic configuration of an electric circuit of the digital single-lens reflex camera according to the first embodiment. The digital single-lens reflex camera 50 includes a CPU 141 that controls an operation sequence of the entire camera, an illumination unit 101, a photographing lens 120, a half mirror 124, a shutter 126, and an image sensor 127. The imaging element 127 has a rectangular imaging unit with an aspect ratio of 3: 2.

  The digital single-lens reflex camera 50 includes a finder device 130, a zoom / focus / anti-vibration driving circuit 134, an aperture driving circuit 135, a shutter driving circuit 138, and a dust-proof mechanism driving circuit 169.

  The digital single-lens reflex camera 50 includes a switch input unit 142, an EEPROM 143, a signal processing circuit 145, an illumination control circuit 146, an EPROM 147, an SDRAM 148, and a flash memory 150.

  The photographing lens 120 includes a plurality of lens groups 121, 167, and 123, and a diaphragm mechanism 122 is provided between these lens groups. The lens groups 121, 167, and 123 are driven by a zoom / focus / anti-vibration driving circuit 134. The aperture mechanism (simply referred to as aperture) 122 is driven by an aperture drive circuit 135.

  A fixed half mirror 124 is provided behind the lens groups 121, 167, and 123. The half mirror 124 divides incident visible light (incident light) into transmitted light and reflected light at a ratio of about 1: 1.

  The zoom / focus / anti-vibration drive circuit 134 includes a drive source such as a known electromagnetic motor or ultrasonic motor, a driver circuit that controls these drive sources, an encoder device that detects the position of the lens, and the like. In zoom control and focus control, the positions of the lens groups 121, 167, and 123 in the optical axis direction are controlled. In the image stabilization control, the position of the lens group 167 in the direction orthogonal to the optical axis is controlled. A finder optical system is provided on the reflected light path of the half mirror 124. The finder optical system includes a focusing screen 131, a pentaprism 132 made of optical glass, an eyepiece 133, and the like. The viewfinder device 130 has a configuration in which a liquid crystal display 108, a prism 154, and the like are added to the viewfinder optical system.

  Subject light (incident light) that has passed through the lens groups 121, 167, and 123 of the photographic lens 120 is reflected by the half mirror 124 and imaged on the focusing screen 131. The observer visually recognizes the optical subject image (optical image) formed on the focusing screen 131 through the single eyepiece window 168 via the pentaprism 132 and the eyepiece lens 133. The advantage of observing the optical image is that there is virtually no time delay.

  Behind the half mirror 124, a shutter 126, a dust removing mechanism 169, and an image sensor 127 such as a CCD or a CMOS imager are provided.

  The shutter 126 is driven by the shutter drive circuit 138 when a still image is acquired, and is opened for a predetermined time to guide the subject image to the light receiving surface of the image sensor 127.

  In the live view mode, the shutter 126 remains open, and the exposure time is controlled by an electronic shutter (not shown) (switching of the ON / OFF switch of the image sensor). In this state, the image sensor 127 is exposed for a certain period of time for each frame, and the shutter speed and the image sensor sensitivity are set based on the luminance information of the obtained image.

  The dust removing mechanism 169 mechanically vibrates the optical low-pass filter and the infrared cut filter, applies acceleration to the foreign matter attached thereto, and shakes off the foreign matter with the generated force.

  A zoom / focus / anti-vibration drive circuit 134, an aperture drive circuit 135, and a dust removal mechanism drive circuit 169 are connected to a CPU 141 formed of a microprocessor via a data bus 152. Further, a shutter drive circuit 138 and an illumination control circuit 146 are also connected to the CPU 141 via the data bus 152. The CPU 141 is connected to a switch input unit 142 and an EEPROM 143 that is a nonvolatile memory via a data bus 152.

  The switch input unit 142 is linked to a first release switch that is turned on in response to a half-pressing operation of a release button (not shown) provided on the exterior casing of the camera, and a deep-pressing operation of the release button. A second release switch that is turned on; The user can give a shooting preparation instruction to the camera by turning on the first release switch and a shooting instruction by turning on the second release switch. Specific operations relating to shooting preparation and shooting will be described later. In addition, the switch input unit 142 includes a plurality of switches such as a switch interlocking with a power switch of the camera and a mode switch interlocking with various mode buttons in the camera. The switch input unit 142 supplies an operation signal based on any switch operation to the CPU 141.

  The EEPROM 143 is a nonvolatile semiconductor memory. The EEPROM 143 stores adjustment values for each camera that are necessary for shipping in a production process while suppressing variations in individual cameras. The EEPROM 143 stores a coefficient indicating the relationship between the BV value and the backlight light amount for the CPU 141 to define the light amount of the backlight 108b, which will be described later, based on the output from the image sensor 127.

  In the live view mode, the subject image formed on the light receiving surface of the image sensor 127 is continuously converted into a digital image signal with the operation of the electronic shutter.

  At this time, focusing is performed by hill-climbing AF, which is a known technique as a focus adjustment operation, using digital image signals that are continuously converted. When the first release switch is turned on, the CPU 141 performs a focusing operation and a focus confirmation operation by hill-climbing AF. A specific focus confirmation operation will be described later. Further, the CPU 141 identifies an optimum focus position. Further, subject luminance information (BV value) for performing exposure control is obtained from the series of calculation results.

  In addition, when the second release switch is turned on, the CPU 141 obtains an appropriate aperture value, shutter speed, and image sensor sensitivity based on subject luminance information based on the output of the image sensor 127. The CPU 141 drives the aperture mechanism 122 via the aperture drive circuit 135 with the obtained aperture value. The CPU 141 drives the shutter 126 via the shutter driving circuit 138 at the determined shutter time.

  Further, the CPU 141 refers to a coefficient indicating the relationship between the BV value stored in the EEPROM 143 and the backlight light amount, determines the amount of current to be supplied to the backlight 108b, and obtains a light amount appropriate for visual recognition.

  When the subject image is formed on the light receiving surface of the image sensor 127 by the opening operation of the shutter 126, the subject image is converted into an analog image signal, and further converted into a digital image signal in the signal processing circuit 145.

  The signal processing circuit 145 includes a RISC processor, a color processor, and a JPEG processor, and performs image processing such as digital image signal compression / expansion processing, white balance processing, and edge enhancement processing. Further, the signal processing circuit 145 performs a conversion process to a composite signal (luminance signal, color difference signal) output to the liquid crystal display 108.

  The CPU 141 and the signal processing circuit 145 are connected by a communication line 153. Via this communication line 153, control signals such as image signal capture timing and data are transmitted and received.

  The composite signal generated by the signal processing circuit 145 is output to the liquid crystal display 108 in the viewfinder device 130, and an electronic subject image is displayed. The liquid crystal display 108 is provided between the pentaprism 132 and the eyepiece 133. The liquid crystal display 108 includes an LCD (liquid crystal display element) 108a that is a display element for displaying a color image, and a backlight 108b for illuminating the display surface of the LCD 108a from the rear. For the backlight 108b, for example, a white LED is used.

  The pentaprism 132 has a surface 154b obtained by extending the third reflecting surface 132a (see FIG. 3), and a prism 154 having the same refractive index as that of the pentaprism 132 is fixed by using an index matching adhesive. ing. The light beam emitted from the liquid crystal display 108 is reflected twice inside the prism 154 and guided toward the eyepiece lens 133. At this time, the display surface of the LCD 108a of the liquid crystal display 108 is in an optically equivalent position to the focusing screen 131 due to the curvature of the surface 154a. The image displayed on the LCD 108 a can be observed through the eyepiece window 168 regardless of whether the movable mirror 124 is in the first position or the second position. The brightness of the image displayed on the LCD 108a is adjusted to an appropriate brightness by changing the current supply amount of the white LED that is the backlight 108b.

  The signal processing circuit 145 is connected to the EPROM 147, the SDRAM (Synchronous Dynamic Random Access Memory) 148, and the flash memory 150 via the data bus 151.

  The EPROM 147 stores a program to be processed by a processor (CPU) included in the signal processing circuit 145. The SDRAM 148 is a volatile memory that temporarily stores image data before image processing, image data during image processing, or image data immediately after image processing. The flash memory 150 is a non-volatile memory that stores finally finalized image data. The SDRAM 148 can perform high-speed operation, but when the power supply is stopped, the stored contents disappear. On the other hand, the flash memory 150 operates at a low speed, but the stored contents are preserved even when the camera is turned off.

  The lighting unit 101 includes a light-emitting panel 103, a reflector 118, and high-brightness LEDs 119 for each color of RGB. The light emitted from the high-intensity LED is reflected directly or by the reflector 118, passes through the light emitting panel 103, and is irradiated toward the subject. The illumination control circuit 146 determines the light quantity balance of each RGB color under the control of the CPU 141, and controls the light emission instruction to the high brightness LED 119.

  FIG. 2 is a block diagram showing the configuration of the electric circuit of the signal processing circuit 145 and peripheral circuits connected thereto. The signal processing circuit 145 includes a CPU 500 serving as a control circuit that controls the signal processing operation, and a plurality of circuits that are connected to the CPU 500 and operate according to control signals from the CPU 500. The CPU 500 is connected to the camera sequence control CPU 141 via the communication line 153, and controls each circuit in the signal processing circuit 145 in accordance with a control signal transmitted from the CPU 141. In the signal processing circuit 145, a first image processing circuit 501, a thinning / extraction processing circuit 502, a second image processing circuit 506, and a third image processing circuit 503 are provided as a plurality of circuits. In the signal processing circuit 145, a video decoder 504, a white balance processing circuit 505, and a JPEG compression / decompression processing circuit 507 are provided.

  The first image processing circuit 501 drives the image sensor 127 according to the drive conditions set by the CPU 500, and performs pre-processing for generating a digital image signal by A / D converting the analog image signal output from the image sensor 127 Circuit. Further, the first image processing circuit 501 corrects the digital image signal based on the pixel signal of the light shielding portion of the image sensor 127.

  The thinning / extraction processing circuit 502 performs thinning processing on the digital image signal output from the first image processing circuit 501 and outputs the thinned image to the second image processing circuit 506 and the third image processing circuit 503. Here, the thinning-out process is a process for reducing the resolution. Note that the digital image signal output to the third image processing circuit 503 is a signal of an electronic subject image displayed on the liquid crystal display 108. Further, the CPU 500 processes the signal obtained from the second image processing circuit 506 to calculate the contrast value of the image, which is the focus evaluation value of the above-described hill-climbing AF, and the value is sent to the CPU 141.

  The thinning / extraction processing circuit 502 extracts a part of the digital image signal and outputs it to a white balance processing circuit (hereinafter referred to as a WB processing circuit) 505. A method of extracting the digital image signal is instructed by the CPU 141.

  The WB processing circuit 505 is a circuit that outputs white balance information (WB information) for adjusting the color balance (white balance) of an image. This WB information is sent directly to the third image processing circuit 503, and is sent to the second image processing circuit 506 via the CPU 141.

  The third image processing circuit 503 is a circuit that generates a display image of the liquid crystal display 108. The third image processing circuit 503 is a simple post-processing circuit, and is a known post-processing circuit such as γ correction, reduction in the number of data bits, color adjustment based on WB information, conversion from RGB signals to YCbCr signals, and the like. Process. In general, when the captured image is repeatedly displayed on the liquid crystal display 108, the speed by software processing is often not in time. Accordingly, all the image processing for display is processed by hardware by the third image processing circuit 503.

  The video decoder 504 converts the YCbCr signal constituting the digital image signal into an NTSC signal to form an electronic subject image, and displays the electronic subject image on the LCD 108 a of the liquid crystal display 108. Note that the display surface of the LCD 108a is illuminated from behind by the backlight 108b with the amount of light defined by the CPU 141.

  The second image processing circuit 506 is a circuit that generates the digital image signal to be stored in the flash memory 150. The second image processing circuit 506 is, as a subsequent processing circuit, γ correction, reduction of the number of data bits of the digital image signal, color adjustment based on WB information, conversion from RGB signal to YCbCr signal, defective pixel of the image sensor 127 A known process such as correction, smear correction, hue or chromaticity is performed.

  The JPEG compression / decompression processing circuit 507 performs JPEG compression processing when the digital image signal processed by the second image processing circuit 506 is stored in the flash memory 150. The JPEG compression / decompression processing circuit 507 reads and decompresses the JPEG image stored in the flash memory 150.

  FIG. 3 is a cross-sectional view showing the configuration of the finder device 130. FIG. 4 is a side view showing the configuration of the viewfinder device 130 when viewed from the direction of arrow A in FIG. A focusing screen 131, a condenser lens 180, and a pentaprism 132 are provided on the optical path reflected and branched by the movable mirror 124 shown in FIG. The subject light imaged on the focusing screen 131 by the lens groups 121, 167, and 123 of the photographing lens 120 is transmitted through the condenser lens 180 and the pentaprism 132, and is directed from the surface 132b to the eyepiece window 168 surrounded by the eye cup 186. To inject. At this time, the subject light passes through the dichroic mirror 182 and passes through the eyepiece lens 133 including the three lenses 133a, 133b, and 133c, and is then protected by the eye cup 186 and is viewed by the eye of the observer. Reach and re-image on the retina.

  The dichroic mirror 182 emits the organic EL display element 185 and reflects the light transmitted through the mirror 184 and the diopter matching lens 183 toward the eyepiece window 168. The field mask 179 has a rectangular opening indicating a subject image range imaged by the image sensor 127. The viewfinder observer can see the distance measuring point position information 197 (see FIG. 8) of the focus detection device 139 shown on the organic EL display element 185 superimposed on the subject image in the field mask 179.

  FIG. 5 is a diagram showing a screen of the LCD 108 a of the liquid crystal display 108. The LCD 108a of the liquid crystal display 108 has a color display unit 108c having an aspect ratio of 4: 3. The display unit 108c provides an LCD display area 108d and a flat horizontally long LCD display area 108e having the same 3: 2 aspect ratio as the image sensor 127 for displaying electronic images within the viewfinder field.

  The light beam 193 emitted from the LCD display area 108d of the LCD 108a enters the pentaprism 132 from the surface 132b of the pentaprism 132. A light beam incident on the pentaprism 132 is a light beam 192. The light beam 192 that has been refracted and changed in direction then enters the surface 132a. Silver vapor deposition is performed on the surface 132a. The light beam 192 is reflected here and enters the prism 154 fixed to the pentaprism 132 by adhesion. The light beam 192 is reflected again by the silver-deposited surface 154a, and is further reflected back to the silver-deposited surface 154b of the prism 154 that is continuous with the surface 132a of the pentaprism 132. The light beam 192 is emitted from the surface 132 b of the pentaprism 132 toward the eyepiece window 168.

  In this way, by configuring the reflection optical path in the prism 154, the optical path length from the eyepiece lens 133 to the LCD display area 108d becomes close to the optical path length from the eyepiece lens 133 to the focusing screen 131. The diopter of the LCD display area 108d and the diopter of the focusing screen 131 substantially match.

  Furthermore, by giving a curvature to the surface 154a of the prism 154, the diopter of the LCD display area 108d and the diopter of the focusing screen 131 can be matched more accurately. At this time, even if the surface 154a is a flat surface, the diopters of both surfaces are close to each other so that the curvature of the surface 154a may be very weak. Further, although the reflection optical path of the surface 154a is an eccentric system, the deterioration of various optical aberrations is negligible.

FIG. 6 is a diagram showing the incident state of light rays on the pentaprism 132. Of the light beam 193 emitted the LCD display area 108d of the LCD 108a, the green light 193g is the angle theta ₁ is obliquely incident on the surface 132b of the pentagonal prism 132 is refracted at the interface between air and glass, angle theta ₂ To go inside the pentaprism 132. Since the relationship between the angle θ ₁ and the angle θ ₂ varies depending on the wavelength of light due to the chromatic dispersion of the refractive index of the glass, when the LCD display area 108d is used for electronic image display, the color blur in the vertical direction is maintained. Occurs, resulting in an image with poor resolution. Therefore, the electronic image displayed in the LCD display area 108d is previously shifted from the RGB image by the amount of positional deviation caused by chromatic dispersion.

  FIG. 7 is a diagram showing a positional shift state of the electronic image displayed in the LCD display area 108d. In the LCD display area 108d, a red electronic image 194r, a green electronic image 194g, and a blue electronic image 194b are vertically shifted in position. As a result, one light beam 193r, 193g, 193b emitted from the corresponding position of the red electronic image 194r, the green electronic image 194g, and the blue electronic image 194b is formed inside the pentaprism 132 as shown in FIG. The light beam 192 proceeds. Then, the light beam 192 finally reaches the eyes of the observer in a state where the color blur is almost eliminated.

  A light beam 194 (see FIG. 3) emitted from the display area 108e of the LCD 108a enters the pentaprism 132 from the bottom surface of the pentaprism 132 through the light guide prism 181 and is reflected inside the pentaprism 132 in the same manner as the subject light. And it injects from the surface 132b.

  FIG. 8 is a diagram showing a display in the viewfinder field observed through the eyepiece window. The display in the viewfinder field includes a first display area 191, a second display area 190d, in-focus position information 197, and a third display area 190e. In the first display area 191, an optical image of the subject defined by the opening of the field mask 179 can be observed. The second display area 190d is located above the first display area 191 and displays information by an image based on the LCD display area 108d of the LCD 108a. The third display area 190e is below the first display area 191, and displays information using character strings and icons based on the LCD display area 108e of the LCD 108a. The display luminances of the second display area 190d, the third display area 190e, and the in-focus position information 197 are all controlled to values appropriate for visual recognition based on the output of the image sensor 127.

  The electronic image displayed in the second display area 190d of FIG. 8 displays the electronic image for each frame of the live view with a delay of one frame until the first release switch is turned on. When the first release switch is turned on, the focusing operation is performed in at least one of the predetermined focusing frames, and the image at that time is recorded when the focusing operation is completed. The image recorded at this time is a simple image (frame image) for display on the second display area with a small number of pixels, which is different from that at the time of actual photographing. Then, the image recorded at this time and the focusing frame superimposed on the image are displayed in the second display area. This display state continues until the second release switch is turned on. A specific flow will be described later.

  In the present embodiment, the liquid crystal display 108 is used, but an organic EL display may be used instead. In this case, the backlight 108b is not necessary.

  Next, in the digital single-lens reflex camera having the above-described configuration, an operation when the shutter release, which is an embodiment of the present invention, is switched stepwise will be specifically described with reference to FIG.

  FIG. 9 shows an example of the images of the first display area 191 and the second display area 190d from the focusing operation to the photographing operation, and FIG. 9A shows the state at the time of focusing lock. FIG. 9B shows a state when the composition is changed after focusing.

  In FIG. 9A, the focusing operation is performed by setting a preset focusing frame 196 to the person who is the main subject and turning on the first release switch. Then, when the focusing operation is completed, the frame that was displayed in the live view at that time is acquired, and the focusing frame is superimposed on the corresponding position and displayed in the second display area 190d.

  Thereafter, the user changes the composition so that the person is positioned at the bottom of the screen while maintaining the first release switch on (FIG. 9B). At this time, since the first release switch is kept on, the focused state with respect to the person is maintained (focus lock). As shown in the drawing, even after the composition is changed, the frame image when the focusing operation is performed and the focusing frame superimposed thereon are displayed in the second display area 190d. Therefore, the user can simultaneously observe the subject optical image after the composition change in the first display area 191 and the in-focus target during the focusing operation in the second display area.

  When the release button is pressed deeply (second release switch is turned on), a subject image having a composition observed in the first display area 191 in FIG. 9B is acquired by the image sensor as the main photographing operation. After the processing, it is recorded in the flash memory 150, and a series of photographing operations is completed.

  Next, the photographing operation sequence of the CPU 141 after the first release switch is turned on will be described with reference to FIG. FIG. 10A shows a flow of the live view operation (reference clock operation) when the photographer is looking into the viewfinder in the live view mode of the digital single lens reflex camera. FIG. 10B shows a flow for acquiring a still image when the release button of the switch input unit 142 is pressed deeply (second release on operation). FIG. 10A is a flow whose operation is controlled by the reference clock, and FIG. 10B is an asynchronous flow with respect to the reference clock and is appropriately performed as an interrupt operation.

  In the flow controlled by the reference clock in FIG. 10A, after confirming that the second release is not turned on in step S0 after the first release switch is turned on, the CPU 141 obtains the previous reference clock operation from the SDRAM 148. The obtained frame image data (digital image signal) is read out. Then, a control signal instructing to display the electronic image in the second display area 190d of the finder apparatus 130 is sent to the signal processing circuit 145 (step S1). When receiving this control signal, the signal processing circuit 145 performs processing for converting the image data into a composite signal. The signal processing circuit 145 supplies the composite signal to the liquid crystal display 108 and displays it on the LCD 108a. As a result, the previously acquired frame image is displayed in the second display area 190d of the finder apparatus 130. At the same time, the CPU 141 turns on the electronic shutter (step S2) and starts frame charge accumulation (step S3). In step S4, the CPU 141 stops the charge accumulation operation at the exposure time calculated by the previous photometric calculation. Then, the image signal obtained in step S5 is read and A / D conversion is performed. Thus, a frame image can be acquired by the signal processing circuit 145. Next, the CPU 141 measures the luminance of the subject using the output from the image sensor 127 (step S6). The CPU 141 determines the exposure amount (electronic shutter speed and imaging device sensitivity) in the next frame from the luminance information or the exposure amount in the imaging operation (squeezing amount of the aperture mechanism 122, shutter speed of the shutter 126 and imaging device sensitivity). Is calculated.

  In step S8, it is confirmed whether the focus is already locked. When the focus operation is being performed for the first time after the first release switch is turned on, the focus is not yet locked, and the process proceeds to step S9. If the focusing operation has already been completed and the first release switch is still on, the process proceeds to step S12.

  In step S9, the CPU 141 performs the focusing calculation in the above-described hill-climbing AF, and determines whether or not the focusing is OK. If it is determined that the lens is out of focus, the process proceeds to step S10, and the focus driving operation of the lens groups 121, 167, and 123 is performed again, and the focusing operation is continued. If it is determined in step S9 that the subject is in focus, it is determined whether or not the first release is in an on state (step S11). Return to operation. On the other hand, if the first release switch is kept on in step S11, the focus frame is superimposed on the frame image that is determined to be OK in the focus determination and displayed in the second display area 190d. In step S12, a focusing lock state in which the subsequent focusing operation is not performed is set. In step S13, the frame image is held in the SDRAM 148 in order to continue the display with the focusing frame superimposed on the frame image that has been determined to be in focus in the second display area 190d, and the reference clock operation is terminated. Return to operation.

  In the flow of the second release switch on operation in FIG. 10B, an interrupt is input to the reference clock operation in FIG. 10A when the second release switch is turned on. If it is determined in step S20 that the second release switch is turned on, the image sensor operation is turned off in step S21. Subsequently, in step S22, the display of the frame image and the focusing frame displayed in the second display area 190d is turned off.

  Further, in step S23, the aperture operation of the aperture mechanism 122 is performed via the aperture drive circuit 135 based on the aperture amount calculated in step S6 of FIG.

  In step S <b> 24, the CPU 141 sends a signal instructing start of imaging to the signal processing circuit 145. Upon receiving this signal, the signal processing circuit 145 starts the charge accumulation operation of the image sensor 127. In step S25, the shutter 126 is opened and closed based on the shutter speed calculated in step S6.

  In step S <b> 26, after closing the shutter 126, the CPU 141 sends a signal that instructs the signal processing circuit 145 to stop imaging. Upon receiving this signal, the signal processing circuit 145 ends the charge accumulation operation in the image sensor 127. Further, the signal processing circuit 145 reads out an image signal from the image sensor 127, performs analog-digital (A / D) conversion, converts it into a digital image signal, and executes image processing associated therewith. Then, the CPU 141 sends a control signal for instructing storage of the digital image signal to the signal processing circuit 145 (step S27). Upon receiving this signal, the signal processing circuit 145 stores the processed image signal in the SDRAM 148 in order.

  Next, in step S <b> 28, the CPU 141 returns the aperture mechanism 122 from the aperture state to the open state via the aperture drive circuit 135. In step S 29, the CPU 141 instructs the signal processing circuit 145 to store the image temporarily stored in the SDRAM 148 in a predetermined storage area of the flash memory 150. Thereafter, the CPU 141 returns to the main routine.

  FIG. 11 is a timing chart showing the camera operation based on the operation sequence of the CPU 141. The figure explains the operation when the photographer is looking through the viewfinder in the live view mode. Specifically, it shows from the first release switch operation of the release button, after the first release switch operation of the release button, to the still image shooting of one frame by the second release switch operation of the release button and to the release button OFF. .

  First, at time T1, when the reference clock rises with the first release switch turned off, the electronic shutter, the charge accumulation of the image sensor, and the electronic image display of the previous frame are simultaneously performed. Next, at time T2, when the charge accumulation of the image sensor is completed, reading and A / D conversion are performed. When A / D conversion is completed at time T3, photometric calculation and focusing calculation are performed. If the focus determination is OK at time T4, the lens drive is not performed. If the focus determination is not OK, the CPU 141 performs the focus drive operation.

  Next, an operation after the first release switch is switched from OFF to ON at time T5 will be described. Basically, the same operation as before is performed, but if the focus determination is OK, the electronic image that is first determined to be in focus is displayed until the second release switch is turned on.

  When the second release switch is switched from OFF to ON at time T7, the operation mode of the image sensor and the electronic image display are turned off, and the diaphragm 122 of the photographing lens 120 is narrowed.

  At time T8, the charge accumulation operation of the image sensor 127 for the image I is started, and the shutter 126 is opened and closed at time T9. When the shutter 126 is closed, the charge accumulation operation of the image sensor 127 is stopped at time T10, and reading of the image signal of the image A and A / D conversion are started. Further, the aperture 122 is opened.

  When the reading of the image signal of the image I and the A / D conversion are completed at time T11, the digital image signal is temporarily stored in the data storage area of the SDRAM 148.

  At time T12, when the deep release operation of the release button is finished and the second release switch is turned off, the imaging operation is finished.

  From the time T12 when the second release switch operation of the release button is completed to the time when the first release switch operation of the release button at the time T13 is completed and the first release switch is turned off, the above-described reference clock operation is repeated. Even after the first release switch at time T13 is turned off, the above-described reference clock operation is repeated.

  In the above operation sequence, reading of the image signal, A / D conversion, storing of the image data in the memory (SDRAM 148), and opening of the aperture 122 are photographing preparation operations for the next frame. The electronic image displayed in the second display area 190d is updated in synchronization with this shooting preparation operation.

  As described above, according to the camera of the first embodiment, it is possible to observe the optical image of the subject without taking his eyes off the viewfinder, and the state and alignment of the subject when the focus is locked with the electronic image. The focal position can be confirmed. Therefore, even if the composition is changed after focusing, it is possible to intuitively visually recognize in which area of the subject the composition is focused, making it easy to set the composition, and realizing an imaging device that hardly misses a photo opportunity. it can. Further, since the optical image and the electronic image do not overlap each other, both can be seen well.

[Second Embodiment]
The digital single-lens reflex camera of the present embodiment is a still camera that captures a subject image with a CMOS image sensor, and has substantially the same configuration as that shown in FIG. 1 as the first embodiment. The difference is that the image sensor 127 itself has a phase difference detection function, and AF is possible based on this signal.

  A configuration and an operation unit different from those in the first embodiment will be described.

  FIG. 12 is a schematic circuit configuration diagram of an image sensor according to the second embodiment of the present invention (see Japanese Patent Application Laid-Open No. 09-046596). This figure shows a range of 2 columns × 4 rows of pixels of a two-dimensional CMOS area sensor, but when used as an image sensor, a large number of pixels are arranged to enable acquisition of a high resolution image.

In FIG. 12, 1301 is a photoelectric conversion portion of a photoelectric conversion element comprising a MOS transistor gate and a depletion layer under the gate, 1302 is a photogate, 1303 is a transfer switch MOS transistor, and 1304 is a reset MOS transistor. 1305 is a source follower amplifier MOS transistor, 1306 is a horizontal selection switch MOS transistor, 1307 is a load MOS transistor of the source follower, and 1308 is a dark output transfer MOS transistor. 1309 is a light output transfer MOS transistor, 1310 is a dark output storage capacitor C _TN , and 1311 is a bright output storage capacitor C _TS . 1312 is a horizontal transfer MOS transistor, 1313 is a horizontal output line reset MOS transistor, 1314 is a differential output amplifier, 1315 is a horizontal scanning circuit, and 1316 is a vertical scanning circuit.

  FIG. 13 shows a cross-sectional view of the pixel portion. In this figure, 1317 is a P-type well, 1318 is a gate oxide film, 1319 is first-layer poly-Si, 1320 is second-layer poly-Si, and 1321 is an n + floating diffusion portion (FD). The FD 1321 is connected to another photoelectric conversion unit via another transfer MOS transistor. In the figure, the drain of two transfer MOS transistors 1303 and the FD portion 1321 are shared to improve the sensitivity by miniaturization and the capacity reduction of the FD portion 1321, but the FD portion 1321 may be connected by an Al wiring. .

  Next, the operation will be described with reference to the timing chart of FIG. This timing chart is for the case of all pixel independent output.

  First, according to the timing output from the vertical scanning circuit 1316, the control pulse φL is set to high to reset the vertical output line. Further, the control pulses φR0, φPG00, and φPGe0 are set high, the reset MOS transistor 1304 is turned on, and the first-layer poly Si 1319 of the photogate 1302 is set high. At time T0, the control pulse φS0 is set high, the selection switch MOS transistor 1306 is turned on, and the pixel portions of the first and second lines are selected. Next, the control pulse φR0 is set to low, the reset of the FD unit 1321 is stopped, and the FD unit 1321 is set in a floating state. Then, after the source-follower amplifier MOS transistor 1305 is made through between the gate and the source, the control pulse φTN is set high at time T1, and the dark voltage of the FD unit 1321 is output to the storage capacitor CTN1310 by the source follower operation.

  Next, in order to perform photoelectric conversion output of the pixels on the first line, the control pulse φTX00 on the first line is set to high to turn on the transfer switch MOS transistor 1303, and then the control pulse φPG00 is lowered to low at time T2. At this time, a voltage relationship is preferable in which the potential well that has spread under the photogate 1302 is raised so that the photogenerated carriers are completely transferred to the FD portion 1321. Therefore, if complete transfer is possible, the control pulse φTX may be a fixed potential instead of a pulse.

At time T2, the charge from the photoelectric conversion unit 1301 of the photodiode is transferred to the FD unit 1321, so that the potential of the FD unit 1321 changes according to light. At this time, since the source follower amplifier MOS transistor 1305 is in a floating state, the potential of the FD unit 1321 is output to the storage capacitor C _TS 1311 with the control pulse φTs being high at time T3. At this time, the dark output and the light output of the pixels on the first line are stored in the storage capacitors C _TN 1310 and C _TS 1311 respectively, and the horizontal output line reset MOS transistor 1313 is turned on by temporarily setting the control pulse φHC at time T4 to high. To reset the horizontal output line. In the horizontal transfer period, the dark output and the light output of the pixel are output to the horizontal output line by the scanning timing signal of the horizontal scanning circuit 1315. At this time, if the differential output VOUT is taken by the differential amplifier 1314 of the storage capacitors C _TN 1310 and C _TS 1311, a signal with good S / N from which random noise and fixed pattern noise of the pixel are removed can be obtained. The photocharge pixel 30-12,30-22 but are accumulated in the storage capacitor CTN10 and _C TS 1311 of people each simultaneously pixel 30-11,30-21, the read timing pulse from the horizontal scanning circuit 1315 It is delayed by one pixel and read out to the horizontal output line and output from the differential amplifier 1314.

  In the present embodiment, the configuration in which the differential output VOUT is performed in the chip is shown. However, the same effect can be obtained even if a conventional CDS (Correlated Double Sampling) circuit is used outside without being included in the chip. Is obtained.

After outputting a bright output to the accumulation capacitor _C TS 1311, to reset the FD section 1321 to turn on the reset MOS transistor 4 a control pulse φR0 as high to the power supply VDD. After the horizontal transfer of the first line is completed, the second line is read. Reading of the second line, control pulses FaiTXe0, likewise not driven control pulses FaiPGe0 control pulse .phi.Tn, supplies each high pulse on FaiTS, accumulates each photoelectric charge accumulation capacitor _C TN 1310 and _C TS 1311, Take out dark output and bright output. With the above driving, the first and second lines can be read independently. Thereafter, by scanning the vertical scanning circuit and reading out the second n + 1 and second n + 2 (n = 1, 2,...) In the same manner, all the pixels can be independently output. That is, when n = 1, first, the control pulse φS1 is set to high. Then, φR1 is set to low, then the control pulses φTN and φTX01 are set to high, the control pulse φPG01 is set to low, the control pulse φTS is set to high, and the control pulse φHC is set to high temporarily, so that the pixel signals of the pixels 30-31 and 30-32 Is read. Subsequently, the control pulses φTXe1, φPGe1 and the control pulse are applied in the same manner as described above, and the pixel signals of the pixels 30-41 and 30-42 are read out.

  15 to 16 are diagrams for explaining the structures of the imaging pixels and the focus detection pixels. In the present embodiment, out of 4 pixels of 2 rows × 2 columns, pixels having G (green) spectral sensitivity are arranged in 2 diagonal pixels, and R (red) and B (blue) are arranged in the other 2 pixels. A Bayer arrangement in which one pixel each having a spectral sensitivity of 1 is arranged is employed. Further, focus detection pixels having a structure to be described later are arranged in a distributed manner between the Bayer arrays.

FIG. 15 shows the arrangement and structure of the imaging pixels. FIG. 2A is a plan view of 2 × 2 imaging pixels. As is well known, in the Bayer array, G pixels are arranged diagonally, and R and B pixels are arranged in the other two pixels. The structure of 2 rows × 2 columns is repeatedly arranged.
A cross section AA of FIG. 4A is shown in FIG. ML denotes an on-chip microlens arranged in front of each pixel, CF _R is a color filter, CF _G of R (Red) is a color filter of G (Green). PD schematically shows the photoelectric conversion unit of the CMOS sensor described in FIG. 3, and CL is a wiring layer for forming signal lines for transmitting various signals in the CMOS sensor. TL schematically shows the photographing optical system.

  Here, the on-chip microlens ML and the photoelectric conversion unit PD of the imaging pixel are configured to capture the light beam that has passed through the photographing optical system ML as effectively as possible. In other words, the exit pupil EP of the photographing optical system TL and the photoelectric conversion unit PD are conjugated with each other by the microlens ML, and the effective area of the photoelectric conversion unit is designed to be large. Further, in FIG. 5B, the incident light beam of the R pixel has been described, but the G pixel and the B (Blue) pixel have the same structure. Accordingly, the exit pupil EP corresponding to each of the RGB pixels for imaging has a large diameter, and the S / N of the image signal is improved by efficiently capturing the light flux from the subject.

FIG. 16 shows the arrangement and structure of focus detection pixels for performing pupil division in the horizontal direction (lateral direction) of the photographic lens. FIG. 5A is a plan view of 2 × 2 pixels including focus detection pixels. When obtaining an imaging signal, the G pixel is a main component of luminance information. Since human image recognition characteristics are sensitive to luminance information, image quality degradation is likely to be recognized if G pixels are lost. On the other hand, the R or B pixel is a pixel that acquires color information. However, since humans are insensitive to color information, pixels that acquire color information are less likely to notice image quality degradation even if some defects occur. Therefore, in the present embodiment, among the pixels of 2 rows × 2 columns, the G pixel is left as an imaging pixel, and the R and B pixels are used as focus detection pixels. This is indicated by SH _A and SH _B in FIG.
A cross section AA of FIG. 4A is shown in FIG. The microlens ML and the photoelectric conversion unit PD have the same structure as the imaging pixel shown in FIG. In the present embodiment, since the signal of the focus detection pixel is not used for image generation, a transparent film CF _W (White) is disposed instead of the color filter for color separation. Moreover, since pupil division is performed by the image sensor, the opening of the wiring layer CL is biased in one direction with respect to the center line of the microlens ML. Specifically, since the opening SHHA of the pixel SH _A and the opening OPHA are biased to the right side, the light beam that has passed through the left exit pupil EPHA of the photographic lens TL is received. Similarly, since the opening OPHB of the pixel SH _B is biased to the left side, the light beam that has passed through the right exit pupil EPHB of the photographic lens TL is received. Therefore, the pixels SH _A are regularly arranged in the horizontal direction, and the subject image acquired by these pixel groups is defined as an A image. Further, the pixels SH _B are also regularly arranged in the horizontal direction, and assuming that the subject image acquired by these pixel groups is a B image, the relative position between the A image and the B image is detected, so that the subject image defocus amount ( Defocus amount) can be detected.

  In the digital single-lens reflex camera having the above configuration, a moving object prediction function which is a known technique can be added by using the above-described phase difference AF pixel. Here, the operation when the shutter release according to the embodiment of the present invention is switched in stages in the moving object prediction mode will be described.

  First, while looking through the optical image in the viewfinder, the release button of the switch input unit 142 is half-pressed (first release switch is turned on) aiming at the subject to be focused. At this time, the focusing operation is performed by the above-described phase difference AF, and the focus is drawn (at the time of moving object prediction lock). At the same time, the obtained image and red that is an index of focus OK are aligned with the focus distance measurement position. The image is displayed in the second display area 190d. If the release button is half-pressed (first release switch-on operation), the display image in the second display area 190d remains as it is, and the state in which it is possible to confirm which subject has been focused is maintained. If the moving object prediction is performed in this state, it is possible to confirm the state of the moving subject in the first display area 191 without changing the image on the second display area 190d.

  FIG. 17 shows an example of the state of the images in the first display area 191 and the second display area 190d when the above operation is performed. FIG. 17 (a) shows the state at the time of moving object prediction lock, and FIG. ) Shows a state immediately before the release button is pressed down, and FIG. 17C shows a state at the time of shooting the second frame.

  When the release button is pressed deeply (second release switch is turned on), an image of the composition observed in the first display area 191 in FIGS. 17B and 17C is acquired by the imaging device, and finally Image data can be stored in a memory (SDRAM 148). At this time, before the release button is pressed deeply (second release switch is turned on), the electronic image and the focal position at the time of moving object prediction are displayed in the second display area 190d. By displaying the in-focus position, the photographer is informed that the subject is in focus. The first display area 191 displays the assumed focus position of the subject from the subject movement vector calculated by the moving object prediction. Further, while the release button is pressed deeply (second release switch is on), video display such as an electronic image from the second display area 190d is turned off. This is to prevent video such as an electronic image from being mixed into the image sensor 227 via the finder device 230 and the half mirror 224.

  Subsequently, an operation sequence of the CPU 141 in the second embodiment will be described. FIG. 18 is a flowchart of the live view operation (reference clock operation) with respect to the operation when the photographer is looking into the viewfinder when the digital single-lens reflex camera is in the live view mode and the moving object prediction mode. Shown in FIG. 18B is a flowchart for acquiring a still image when the release button of the switch input unit 142 is pressed deeply (second release switch-on operation). The flowchart shown in FIG. 18 is a subroutine called in the main flowchart of the CPU 141. FIG. 18A is a flow whose operation is controlled by the reference clock, and FIG. 18B is a flow asynchronous with the reference clock, and an interrupt operation is appropriately performed.

  In the flow whose operation is controlled by the reference clock in FIG. 18A, after confirming that the second release is not turned on in step S30 after the first release switch is turned on, the CPU 141 obtains the previous reference clock operation from the SDRAM 148. The read image data is read out. Then, a control signal instructing to display the electronic image on the second display area 190d of the finder apparatus 130 is sent to the signal processing circuit 145 (step S31). Upon receiving this control signal, the signal processing circuit 145 performs processing for converting this image data into a composite signal. The signal processing circuit 145 supplies the composite signal to the liquid crystal display 108 and displays it on the LCD 108a. As a result, the frame image captured last time is displayed in the second display area 190d of the finder device 130. At the same time, the CPU 141 turns on the electronic shutter (step S32) and starts frame charge accumulation (step S33). In step S34, the CPU 141 stops the charge accumulation operation at the timing of the exposure time calculated by the previous photometric calculation. Then, the image signal obtained in step S35 is read and A / D conversion is performed. In this way, the frame image can be acquired by the signal processing circuit 145. Next, the CPU 141 measures the luminance of the subject using the output from the image sensor 127 (step S36). Based on the luminance information, an exposure amount in the next frame (electronic shutter speed and imaging device sensitivity) or an exposure amount in the imaging operation (aperture amount of the aperture mechanism 122, shutter speed of the shutter 126 and imaging device sensitivity) is set to a predetermined value. Calculate according to the calculation program.

  In step S <b> 37, the CPU 141 performs a so-called moving object prediction calculation that performs a focusing calculation with the above-described phase difference AF and calculates a movement vector of the subject from changes in a plurality of past defocus amounts. Next, it is determined whether or not the ON state of the first release is continued (step S11). If the ON state is not continued, the reference clock operation is terminated and the operation returns to the initial operation. On the other hand, if the first release switch is kept on in step S11, it is confirmed whether the focus is already locked (step S39). If the focus lock is not performed, the process proceeds to step S41, and the focus drive operation of the lens groups 121, 167, and 123 is performed again, and the focus operation is continued. If the focus is locked, in step S40, the frame image is held in the SDRAM 148 in order to continue the display by superimposing the focus frame on the frame image determined to be OK in the second display area 190d. . Then, the process proceeds to step S41, and the lens group 121, 167, 123 is focus-driven by the CPU 141 so that the subject is in focus after a predetermined time from the focusing calculation and the moving object prediction calculation calculated in step S37, and the focusing operation is performed. to continue. As described above, the reference clock operation is terminated and the initial operation is resumed.

  In the flow of the second release switch-on operation in FIG. 19B, an interrupt is input to the reference clock operation in FIG. 19A when the second release is turned on. If it is determined in step S50 that the second release switch has been turned on, the image sensor operation is turned off in step S51. Subsequently, in step S52, the display of the frame image and the focusing frame displayed in the second display area 190d is turned off.

  Further, in step S23, the aperture operation of the aperture mechanism 122 is performed via the aperture drive circuit 135 based on the aperture amount calculated in step S36 of FIG.

  In step S54, the CPU 141 sends a signal instructing the start of imaging to the signal processing circuit 145. Upon receiving this signal, the signal processing circuit 145 starts the charge accumulation operation of the image sensor 127. In step S55, the shutter 126 is opened and closed based on the shutter speed calculated in step S36.

  In step S <b> 56, the CPU 141 closes the shutter 126, and then sends a signal that instructs the signal processing circuit 145 to stop imaging. Upon receiving this signal, the signal processing circuit 145 ends the charge accumulation operation in the image sensor 127. Further, the signal processing circuit 145 reads out an image signal from the image sensor 127, performs analog-digital (A / D) conversion, converts it into a digital image signal, and executes image processing associated therewith. Then, the CPU 141 sends a control signal for instructing storage of the digital image signal to the signal processing circuit 145 (step S57). Upon receiving this signal, the signal processing circuit 145 stores the processed image signal in the SDRAM 148 in order.

  Next, in step S58, the CPU 141 returns the aperture mechanism 122 from the aperture state to the open state via the aperture drive circuit 135. In step S <b> 59, the CPU 141 instructs the signal processing circuit 145 to store the image temporarily stored in the SDRAM 148 in a predetermined storage area of the flash memory 150. Thereafter, it is determined whether or not the second release switch remains on (step S60). If it is on, the process returns to step S53, and the continuous shooting is repeated. If the second release switch is off, the CPU 141 returns to the main routine.

  FIG. 19 is a timing chart showing the camera operation based on the operation sequence of the CPU 141. In the figure, the operation when the photographer is looking through the viewfinder in the live view mode and the moving object prediction mode is described. Specifically, it shows from before the first release switch operation of the release button, after the first release switch operation of the release button, to still image shooting of continuous shooting by the second release switch operation of the release button and to the release button OFF. ing.

  First, at time T1, when the reference clock rises with the first release switch turned off, the electronic shutter, the charge accumulation of the image sensor, and the electronic image display of the previous frame are simultaneously performed. Next, at time T2, when charge accumulation in the image sensor is completed, reading and A / D conversion are performed. When the A / D conversion ends at time T3, photometric calculation, focusing calculation, and moving object prediction calculation are performed. At time T4, if the first release switch remains off, focus drive is not performed and the next reference clock operation is repeated.

  Next, an operation after the first release switch is switched from OFF to ON at time T5 will be described. Basically, the same operation as before is performed, but at time T6, after the focusing and moving object prediction calculation is completed, the lens is driven to focus on the subject at the next exposure. At time T7, when the focus determination is OK for the first time after the first release switch is turned on, this electronic image D is displayed until the second release switch is turned on.

  When the second release switch is switched from OFF to ON at time T8, the operation mode of the image sensor and the electronic image display are turned off, and the diaphragm 122 of the photographing lens 120 is narrowed. Further, based on the moving object prediction calculation so far, the lens is driven so that the subject is in focus when the still image of the first frame is exposed. The charge accumulation operation of the image sensor 127 for the image H is started at time T9, and the shutter 126 is opened and closed at time T10. When the shutter 126 is closed, the charge accumulation operation of the image sensor 127 is stopped at time T11, and reading of the image signal of the image H and A / D conversion are started. Further, the aperture 122 is opened.

  When the reading of the image signal of the image H and the A / D conversion are completed at time T12, the digital image signal is temporarily stored in the data storage area of the SDRAM 148. At the same time, based on the moving object prediction calculation so far, the lens is driven to focus so that the subject is in focus when the still image of the second frame is exposed. Since the second release switch remains on, the charge accumulation operation of the image sensor 227 for the image I is started at time T14, and the shutter 126 is opened and closed at time T15. When the shutter 126 is closed, the charge accumulation operation of the image sensor 127 is stopped at time T16, and reading of the image signal of the image I and A / D conversion are started. Further, the aperture 122 is opened.

  When the reading of the image signal of the image I and the A / D conversion are completed at time T17, the digital image signal is temporarily stored in the data storage area of the SDRAM 148. At this time, since the second release switch is still on, the lens focus drive is performed at time T18 in preparation for the next continuous shooting.

  At time T19, when the deep release operation of the release button is finished and the second release switch is turned off, the imaging operation is finished.

  The above-described reference clock operation is repeated until the half-pressing operation of the release button from time T19 when the release button deep-pressing operation is ended to time T20 ends and the first release switch is turned off. Even after the first release switch at time T20 is turned off, the above-described reference clock operation is repeated.

  In the above operation sequence, reading of an image signal, A / D conversion, storing of image data in a memory (SDRAM 148), and opening of the aperture 222 are photographing preparation operations for the next frame. The electronic image displayed in the second display area 190d is updated in synchronization with this shooting preparation operation.

  As described above, according to the camera of the second embodiment, in the moving object prediction mode, the electronic image at the time when the focus lock is performed while the optical image of the subject can be observed without taking an eye off the viewfinder. And the in-focus position can be confirmed at the same time. Therefore, it is possible to reconfirm whether or not the focus position is intended by the photographer even when the subject has moved. Therefore, it is possible to realize a new camera that does not miss a photo opportunity. As a result, it is possible to prevent shooting failures. Further, since the optical image and the electronic image do not overlap each other, both can be seen well.

[Modification of the above embodiment]
In each of the above embodiments, it is assumed that an AF operation is performed, but the present invention is not limited to this. That is, it is assumed that the user performs focus adjustment by manual operation. If it is determined that one of the subject areas is in focus when the first release switch is turned on, the frame image at that time is captured, and the focus frame is superimposed on the image to display the second display area. You may make it display on 190d. Even with this configuration, it is possible to confirm the state of the subject and the in-focus position from the electronic image while allowing the optical image of the subject to be observed without taking his eyes off the viewfinder.

  In each of the above embodiments, the focus frame is superimposed and displayed as the information on the focus position. However, the present invention is not limited to this. For example, a horizontal line and a vertical line may be displayed, and this intersection may be represented as a focus position, or may be displayed by image processing such that a region other than the focus region is grayscale.

It is a figure which shows schematic structure of the electric circuit of the digital single-lens reflex camera in 1st Embodiment. It is a block diagram which shows the structure of the electric circuit of the signal processing circuit 145, and the peripheral circuit connected to it. It is sectional drawing which shows the structure of the finder apparatus 130. FIG. It is a side view which shows the structure of the finder apparatus 130 at the time of seeing from the arrow A direction of FIG. It is a figure which shows the screen of LCD108a of the liquid crystal display. It is a figure which shows the incident state of the light ray to the pentaprism 132. FIG. It is a figure which shows the position shift state of the electronic image displayed on LCD display area 108d. It is a figure which shows the display in a finder visual field. It is a figure which shows the example of the mode of the image of the 1st display area 191 and the 2nd display area 190d. It is a flowchart which shows the imaging operation procedure in 1st Embodiment. It is a timing chart which shows the camera operation | movement in 1st Embodiment. It is a circuit diagram of the image sensor in a 2nd embodiment. It is a pixel part sectional view of an image sensor in a 2nd embodiment. 9 is a drive timing chart of an image sensor according to the second embodiment. It is the top view and sectional view of an image pick-up pixel of an image sensor in a 2nd embodiment. It is a top view and a sectional view of a pixel for focus detection of an image sensor in a 2nd embodiment. It is a figure which shows the example of the mode of the image of the 1st display area 191 and the 2nd display area 190d. It is a flowchart which shows the imaging operation procedure in 2nd Embodiment. It is a timing chart which shows the camera operation | movement in 2nd Embodiment.

Explanation of symbols

50 Digital SLR Camera 127 Image Sensor 130 Finder Device 141 CPU
168 Eyepiece window 190d Second display area 191 First display area

Claims (5)

An image sensor that photoelectrically converts a subject image formed by the photographing lens;
The first display area where the subject image is observed as an optical image and the second display area where the electronic image photoelectrically converted by the imaging device displayed by the display means can be observed simultaneously through the eyepiece window. A finder means,
Shooting preparation instruction means;
Determining means for determining the in-focus state of the subject image after an instruction to prepare for shooting is given by the shooting preparation instructing means;
While the imaging preparation instruction unit continues to instruct the imaging preparation, the second display area is configured to superimpose information relating to the in-focus position on the image that is determined to be in focus by the determination unit. An image pickup apparatus having display means for displaying on the display. A focus adjusting means for adjusting the focus of the photographic lens when an instruction to prepare for shooting is given by the shooting preparation instructing means;
The imaging apparatus according to claim 1, wherein the determination unit is performed in conjunction with a focus adjustment operation by the focus adjustment unit.   The imaging apparatus according to claim 2, wherein the focus adjustment unit performs focus adjustment by performing phase difference detection based on an output of a pixel provided in the imaging element.   4. The apparatus according to claim 1, further comprising: a half mirror that reflects a part of incident light toward the finder unit and transmits a part of the incident light toward the imaging element. The imaging apparatus of Claim 1. Having shooting instruction means,
5. The imaging apparatus according to claim 1, wherein the display unit terminates the display of the second display area when a shooting instruction is given by the shooting instruction unit. 6.

Images