JP2008028546A - Digital camera capable of recording moving image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-use digital camera that allows to obtain high-image-quality moving images. <P>SOLUTION: The digital camera has a CCD 221, which receives a subject light-flux passing through a photographing lens so as to output a subject image signal, a recording medium 245 for recording subject moving images on the basis of the subject image signal, a movable half mirror 201, which is advanceable into and retreatable from a photographing optical path, a phase-difference AF means, which detects an out-of-focus amount of the photographing lens on the basis of the subject light-flux, reflected by the half mirror, when the half mirror 201 is advanced into the photographing optical path so as to execute focusing operation of the photographing lens on the basis of the detection results, and a contrast AF means that executes the focusing operation of the photographing lens on the basis of contrast information of the subject image signal when the half mirror is retreated from the photographing optical path. The phase-difference AF means and the contrast AF means are selected corresponding to a photographing mode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a digital camera having a moving image shooting function.

Many digital cameras can record not only still images but also moving images. For example, Patent Document 1 discloses a digital single-lens reflex camera that takes a moving image by retracting a quick return mirror (movable mirror) out of the photographing optical path and maintaining the focal plane shutter in a bulb state. However, in the single-lens reflex camera disclosed in Patent Document 1, the movable mirror is retracted out of the photographing optical path during moving image shooting. Therefore, the TTL (Trough The Lens) generally used in conventional single-lens reflex cameras is used. There was a drawback that distance measurement by phase difference AF (Auto Focus) was not possible. However, as disclosed in Japanese Patent Application Laid-Open No. 2004-228688, this disadvantage is that if the movable mirror is formed of a half mirror and the subject luminous flux that has passed through the photographing optical system is guided to both the image sensor and the phase difference AF sensor. It can be solved once.
JP 59-201029 A Japanese Patent Laid-Open No. 2002-6208

As described above, if a half mirror is arranged in the photographing optical path as in Patent Document 2, phase difference AF can be performed even during moving image photographing, so that even a subject moving at high speed can be focused. You can shoot while aligning. However, when a half mirror is placed in the shooting optical path, image degradation such as shift of the subject image, distortion, blur, etc., due to various factors such as the refractive index, thickness, spectral transmittance, and placement angle of the half mirror. Will occur. Therefore, high-quality moving image shooting cannot be performed with subject light transmitted through the half mirror.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a digital camera that is easy to use and can acquire high-quality moving images.

In order to achieve the above object, a digital camera capable of moving image recording according to a first aspect of the present invention includes an imaging means for receiving a subject luminous flux that has passed through a photographing lens and outputting a subject image signal, and a subject image signal based on the subject image signal. Recording means for recording a moving image, a half mirror capable of moving back and forth in the photographic optical path, and the defocusing of the photographic lens based on the subject luminous flux reflected by the half mirror when the half mirror has advanced into the photographic optical path The first focus adjusting means for detecting the amount and performing the focusing operation of the photographing lens based on the detection result, and the contrast information of the subject image signal in a state where the half mirror is retracted from the photographing optical path. The second focus adjusting means for performing the focusing operation of the photographing lens and the half mirror are arranged in the photographing optical path, and the first A first moving image recording mode in which moving image recording is performed while performing a focus adjustment focusing operation; and a first moving image recording in which the half mirror is retracted from the photographing optical path and a focusing operation is performed by the second focus adjustment unit. Selection means capable of selectively setting the second moving image recording mode, and the image quality of the second moving image recording mode is higher than that of the first moving image recording mode.

In the digital camera capable of recording a moving image according to the second invention, in the first invention, the second moving image recording mode has a higher resolution than the first moving image recording mode.
In the digital camera capable of recording a moving image according to the third aspect of the present invention, the second moving image recording mode has a lower compression rate than the first moving image recording mode.
Further, in the digital camera capable of recording a moving image according to the fourth invention, in the first invention, the first moving image recording mode is selected corresponding to a shooting mode suitable for moving body shooting.
Furthermore, in the digital camera capable of recording a moving image according to the fifth invention, in the first invention, the first moving image recording mode is selected corresponding to a shooting mode in which shooting time is more important than image quality.

In order to achieve the above object, a digital camera capable of moving image recording according to a sixth aspect of the present invention includes an imaging means for receiving a subject luminous flux that has passed through a photographing lens and outputting a subject image signal, and a subject image signal based on the subject image signal. Recording means for recording a moving image, and a half mirror capable of moving back and forth in the photographing optical path and guiding a part of the subject light flux to the phase difference AF sensor in the photographing optical path, and recording the moving image by the recording means In accordance with the image quality condition, it is determined whether or not the half mirror is to enter the photographing optical path.

According to a seventh aspect of the present invention, there is provided a digital camera capable of recording a moving image, wherein in the sixth aspect, the image quality when the half mirror is in the photographing optical path is better than the image quality when the half mirror is retracted from the photographing optical path. Set low.

In order to achieve the above object, a digital camera according to an eighth aspect of the invention is an image pickup means for receiving a subject luminous flux that has passed through a photographing lens and outputting a subject image signal, and a recording for recording a subject image based on the subject image signal. Means, a half mirror capable of moving back and forth in the photographing optical path, and a photographing mode setting means for setting a photographing mode, and when the photographing mode set by the photographing mode setting means gives priority to image quality, the imaging means When taking a picture, the half mirror is retracted from the taking optical path of the taking lens to take a picture.

According to a ninth aspect of the present invention, there is provided a digital camera according to the eighth aspect, wherein the defocus amount of the photographing lens is calculated based on the subject light beam reflected by the half mirror in a state where the half mirror has advanced into the photographing optical path. In the state where the first focus adjusting unit that detects and performs the focusing operation of the photographing lens based on the detection result and the half mirror is retracted from the photographing optical path, the first focus adjusting unit is based on the contrast information of the subject image signal. When the second focus adjusting unit that performs the focusing operation of the photographic lens is provided and the half mirror is retracted to perform shooting, the focusing operation is performed by the second focus adjusting unit.
According to a tenth aspect of the present invention, there is provided a digital camera according to the ninth aspect, further comprising recording means for recording image data based on a subject image signal from the imaging means, the recording means being a moving image or a still image. Is selectively recorded.

According to the present invention, the first mirror adjustment focusing operation is performed in which the half mirror is disposed in the imaging optical path, the defocus amount of the imaging lens is detected, and the imaging lens is focused based on the detection result. The first moving image recording mode in which moving image recording is performed and the focus by the second focus adjusting unit that retracts the half mirror from the photographing optical path and performs the focusing operation of the photographing lens based on the contrast information of the subject image signal Since the selection means capable of selectively setting the second moving image recording mode for performing moving image recording while performing the operation is provided, the moving image recording digital that is easy to use and can acquire high-quality moving images A camera can be provided.

Hereinafter, a preferred embodiment using a digital camera to which the present invention is applied will be described with reference to the drawings. This digital camera forms a subject image formed by a photographing lens on an image sensor and displays a moving image on a display device such as a liquid crystal monitor for observing the subject image based on the output of the image sensor. It has a display function (also called a live view display function or an electronic viewfinder function). Further, a still image can be acquired and recorded on a recording medium in accordance with a shooting instruction from the photographer. Furthermore, it is possible to acquire a moving image in accordance with a shooting instruction from the photographer and record it on a recording medium. In acquiring this moving image, a mode that prioritizes image quality and a mode that prioritizes moving image recording time can be selected. Selection of these still images, moving images, image quality priority mode, long-time mode, and the like can be performed in a shooting mode, shooting condition setting, and menu setting described later.

FIG. 1 is a block diagram mainly showing an electric system of a digital camera according to an embodiment of the present invention. The lens barrel 10 is detachable from a mount opening (not shown) on the front surface of the camera body 20. The subject luminous flux from the photographing lens including the lenses 101a and 101b in the lens barrel 10 is guided into the camera body 20 through the mount opening. In the present embodiment, the lens barrel 10 and the camera body 20 are configured separately and are electrically connected via the communication contact 300. The attachment / detachment detection switch 259 provided on the camera body 20 can detect the attachment / detachment state.

Inside the lens barrel 10, there are disposed lenses 101a and 101b for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture. The lens 101 a and the lens 101 b are driven by an optical system driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109. The optical system driving mechanism 107 and the aperture driving mechanism 109 are each connected to a lens CPU 111, and the lens CPU 111 is connected to the camera body 20 via a communication contact 300. The lens CPU 111 controls the lens barrel 10 and controls the optical system driving mechanism 107 to perform focusing and zoom driving, and also controls the diaphragm driving mechanism 109 to control the aperture.

In a mirror box in the camera body 20, a movable reflecting mirror 201 (referred to as a movable half mirror for convenience) having a characteristic of transmitting a part of the light beam that has passed through the lenses 101a and 101b is disposed. The movable half mirror 201 is driven by a movable mirror drive mechanism 215 and can rotate along an axis in a direction perpendicular to the paper surface around a rotation shaft 201a. When the movable half mirror 201 is at a position inclined by 45 degrees with respect to the optical paths of the lenses 101a and 101b (the position indicated by the solid line in FIG. 1), a part (for example, 30%) of the subject luminous flux is reflected, and the camera body 20 Is guided to a distance measuring / photometric sensor 217 provided at the bottom. Further, the remainder (for example, 70%) of the subject luminous flux passes through the movable half mirror 201 and is guided in the direction of the CCD 221.

When the movable half mirror 201 is substantially parallel to the optical paths of the lenses 101a and 101b and is in a retracted position (a position indicated by a two-dot chain line in FIG. 1) that does not block the subject light beam, the entire subject light beam is guided to the CCD 221. The structure of the movable half mirror 201 will be described later with reference to FIG. In the present embodiment, the center of rotation of the movable half mirror 201 is the lower side in the mirror box, but is not limited to this, and may be the upper side or parallel to the paper surface on either the left or right side. Of course, the center of rotation may be used. Moreover, although the rotation center of the movable half mirror 201 is arranged on the CCD 221 side, it is not limited to this and may be arranged on the mount opening side. Furthermore, in this embodiment, the reflectance and transmittance of the half mirror are 30% and 70%, respectively, but are not limited to this ratio and can be changed as appropriate.

A distance measuring / photometric sensor 217 is arranged at the bottom of the mirror box in the camera body 20 at a position where the light beam reflected by the movable half mirror 201 is guided. The distance measuring / photometric sensor 217 includes a distance measuring sensor and a photometric sensor. The photometric sensor includes a multi-division photometric element that divides a subject image and performs photometry. The distance measuring sensor is a sensor for measuring a distance by the TTL phase difference method. The output of the distance measurement / photometry sensor 217 is sent to the distance measurement / photometry processing circuit 219. The distance measurement / photometry processing circuit 219 outputs an evaluation photometric value based on the output of the photometry sensor, and measures the focus shift amount of the subject image formed by the lenses 101 and 101b based on the output of the distance measurement sensor. To do. Note that the distance measuring sensor and the photometric sensor may be configured separately or integrally.

A focal plane type shutter 203 for exposure time control and light shielding of the CCD 221 is disposed behind the movable reflecting mirror 201 and on the optical axis of the lenses 101a and 101b and on the photographing optical path. Is driven and controlled by a shutter drive mechanism 213. A dustproof filter 205 is disposed behind the shutter 203. This is because dust generated in the mount opening of the camera body 20 and inside the body adheres to the CCD 221 and the optical element, and the shadow of the dust is reflected in the subject image. It is a filter to prevent it from becoming unsightly.

A piezoelectric element 207 is fixed to the entire periphery or a part of the periphery of the dustproof filter 205, and this piezoelectric element 207 is connected to the dustproof filter drive circuit 211 and driven by this circuit. The piezoelectric element 207 is driven by the dust filter driving circuit 211 so that the dust filter 205 vibrates with a predetermined ultrasonic wave, and the dust attached to the front surface of the dust filter 205 is removed using the vibration. In addition, as long as dust attached to the image pickup device itself such as a CCD or an optical element disposed on the front side of the image pickup device can be removed, it is not limited to one using ultrasonic vibration as in the present embodiment. Of course, it may be appropriately replaced with various methods such as a method of blowing off by an air flow using an air pump or a method of collecting and removing dust using static electricity.

An infrared cut filter 209 for cutting an infrared light component from the subject light beam is disposed behind the dust-proof filter 205, and an optical low-pass filter 210 for removing a high frequency component from the subject light beam is disposed behind the dust filter 205. ing. A CCD 221 serving as an image sensor is disposed behind the optical low-pass filter 210, and the subject image formed by the lenses 101a and 101b is photoelectrically converted into an electrical signal. The dustproof filter 205, the infrared cut filter 209, the optical low-pass filter 210, and the CCD 221 are integrally stored in a sealed package (not shown), and are configured so that dust does not enter the package. In the present embodiment, a CCD is used as an image sensor. However, the present invention is not limited to this, and a CMOS (Complementary Metal Oxide) is used.
Needless to say, a two-dimensional imaging device such as Semiconductor) can be used.

The CCD 221 is connected to the image sensor driving circuit 223 and is driven and controlled by a control signal from the input / output circuit 239. A photoelectric analog signal output from the CCD 221 is amplified and analog-digital converted (AD converted) by the image sensor driving circuit 223. The image sensor driving circuit 223 is connected to an image processing circuit 227 in an ASIC (Application Specific Integrated Circuit) 262, and the image processing circuit 227 performs digital amplification (digital gain adjustment processing) and color of digital image data. Various types of image processing such as correction, gamma (γ) correction, contrast correction, black and white / color mode processing, through image processing, and moving image processing for recording medium recording are performed. The image processing circuit 227 is connected to the data bus 261. In addition to the image processing circuit 227, the data bus 261 includes a sequence controller (hereinafter referred to as "body CPU") 229, a compression / decompression circuit 231, a video signal output circuit 233, an SDRAM control circuit 237, and an input / output circuit 239. A communication circuit 241, a recording medium control circuit 243, a flash memory control circuit 247, and a switch detection circuit 253 are connected.

The body CPU 229 connected to the data bus 261 controls the operation of this digital camera. A compression / decompression circuit 231 connected to the data bus 261 is a circuit for compressing the image data stored in the SDRAM 238 in a compression format for still images such as JPEG and MJPEG and for moving images. Note that image compression is not limited to JPEG or MJPEG, and other compression methods can be applied. The video signal output circuit 233 connected to the data bus 261 is connected to the rear liquid crystal monitor 26 and the finder liquid crystal monitor 29 (abbreviated as “F liquid crystal monitor” in the figure) via the liquid crystal monitor drive circuit 235. The video signal output circuit 233 is a circuit for converting the image data stored in the SDRAM 238 or the recording medium 245 into a video signal for display on the rear liquid crystal monitor 26 and / or the in-viewfinder liquid crystal monitor 29.

The rear liquid crystal monitor 26 is disposed on the rear surface of the camera body 20. However, the rear liquid crystal monitor 26 is not limited to the rear surface and may be other display devices as long as the photographer can observe. The in-viewfinder liquid crystal monitor 29 is disposed at a position that can be observed by the photographer through the viewfinder eyepiece, and, like the rear liquid crystal monitor 26, is not limited to the liquid crystal and may be another display device. Note that only the rear liquid crystal monitor 26 may be used for observation of the subject image, and the finder eyepiece and the finder liquid crystal monitor 29 may be omitted.

The SDRAM 238 is connected to the data bus 261 via the SDRAM control circuit 237, and the SDRAM 238 temporarily stores the image data processed by the image processing circuit 227 or the image data compressed by the compression / expansion circuit 231. This is a buffer memory. The input / output circuit 239 connected to the above-described dustproof filter drive circuit 211, shutter drive mechanism 213, movable mirror drive circuit 215, distance measurement / photometry processing circuit 219, and image sensor drive circuit 223 is connected to the body CPU 229 via the data bus 261. Control input / output of data with each circuit. The communication circuit 241 connected to the lens CPU 111 via the communication contact 300 is connected to the data bus 261, and exchanges data with the body CPU 229 and the like and communicates control commands.

A recording medium control circuit 243 connected to the data bus 261 is connected to the recording medium 245 and controls recording of image data and the like on the recording medium 245. The recording medium 245 can be loaded with any rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), or a memory stick (registered trademark). And is detachable from the camera body 20. In addition, a hard disk unit such as a microdrive (registered trademark) or a wireless communication unit may be connectable.

A flash memory control circuit 247 connected to the data bus 261 is connected to a flash memory 249. The flash memory 249 stores a program for controlling the flow of the camera. The digital camera is controlled according to the program stored in the flash memory 249. Note that the flash memory 249 is an electrically rewritable nonvolatile memory.

Power switch 257 that is turned on / off in conjunction with a power switch lever for controlling power supply of the camera body 20 and the lens barrel 10, a switch that is linked to a shutter release button, and a playback button that designates a playback mode. , A switch linked to the cross button for instructing the movement of the cursor on the screen of the rear LCD monitor 26, a switch linked to the mode dial for instructing the shooting mode, and an OK linked to the OK button for determining each selected mode. Various switches 255 such as a switch and an attachment / detachment detection switch 259 are connected to the data bus 261 via a switch detection circuit 253.

The release button has a first release switch that is turned on when the photographer is half-pressed and a second release switch that is turned on when the photographer is fully pressed. When the first release switch (hereinafter referred to as 1R) is turned on, the camera performs photographing preparation operations such as focus detection, focusing of the photographing lens, and photometry of the subject brightness, and the second release switch (hereinafter referred to as 2R). When the switch is turned on, a shooting operation for capturing image data of a subject image is executed based on the output of the CCD 221 serving as an image sensor.

Next, the driving means and retracting means of the movable half mirror 201 will be described with reference to FIG. A half mirror 401 that transmits part of the subject luminous flux and reflects part of it is held by a mirror frame 403. The mirror frame 403 is rotatable around a shaft 411 inserted in the hole 403 a, and the rotation shaft 201 a in FIG. 1 is a central axis of the shaft 411. Both ends of an opening spring 407 are engaged between a pin 409 fixed to the camera body 20 and a driving pin 405 implanted in the mirror frame 403, and a coil portion of the opening spring 407 is wound around a shaft 411. It is disguised. Due to the spring force of the opening spring 407, the mirror frame 403 receives a biasing force in the counterclockwise direction (arrow A direction) in the figure. One end of the drive pin 405 and the locking lever 413 are engaged, and the cam pin 415 implanted at the other end of the locking lever 413 is engaged with the mirror cam 417.

The locking lever 413 is pivotally supported by a mirror box (not shown), and receives a biasing force counterclockwise (arrow B direction) in the figure by the spring force of the opening spring 407 via the drive pin 405. Yes. Therefore, the cam pin 415 of the locking lever 413 is in pressure contact with the cam surface of the mirror cam 417. The cam surface of the mirror cam 417 is formed so that the length in the radial direction from the center of rotation changes. That is, the locking position 417a on the cam surface is formed so that the distance from the rotation center is longer, and the locking release position 417b is formed so that the distance from the rotation center is shorter than the locking position 417a. ing. A cam surface is formed with a step 417c from the locking position 417a to the locking release position 417b in the counterclockwise direction in the drawing, and the cam surface is smoothly displaced from the locking release position 417b to the locking position 417a. It is formed.

When the locking position 417a of the mirror cam 417 is in a position where it abuts on the cam pin 415, the locking lever 413 is restricted from rotating in the direction of arrow B by the mirror cam 417. Hold on. From this state, when the mirror cam 417 is rotated clockwise in the drawing to a position where the unlocking position 417b contacts the cam pin 415 through the step 417c, the locking lever 413 is rotated in the arrow B direction. It becomes possible. Therefore, the mirror frame 403 is rotated in the direction of arrow A by the urging force of the opening spring 407 and displaced to the retracted position. The mirror cam 417 is rotationally driven by a motor (not shown).

The driving means for driving the movable half mirror 201 to the reflection position (the position indicated by the solid line in FIG. 2) in the imaging optical path includes a mirror cam 417, a locking lever 413, and the like. Further, the retracting means for driving the movable half mirror 201 to the retracted position (the position indicated by the two-dot chain line in FIG. 2) outside the imaging optical path includes an opening spring 407. The driving unit and the retracting unit are not limited to such a configuration, and other configurations may be used as long as the movable half mirror 201 can be driven.

Since the movable half mirror 201 is configured in this way, when the cam pin 415 is driven to a position in contact with the locking release position 417b by a motor (not shown), the mirror frame 403 and the locking lever 413 are opened and the spring 407 is attached. The mirror frame 403 is moved to the retracted position as shown by a two-dot chain line in the figure by the force. In this state, when the mirror cam 417 is rotated by the motor and the locking position 417a comes into contact with the cam pin 415, the locking lever 413 is rotated in the clockwise direction (the direction opposite to the arrow B direction), and the opening spring 407 is rotated. The mirror frame 403 is rotated clockwise (opposite to the direction of the arrow A) via the drive pin 405 against the urging force, and is positioned at a reflection position as shown by a solid line in the drawing.

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowcharts shown in FIGS. In the power-on reset flow shown in FIG. 3, it is determined whether the power switch 257 of the camera body 20 is turned on (S1). As a result of the determination, if the power switch 257 is off, the process proceeds to step S5 to enter a sleep state that is a state of low power consumption. In this sleep state, interrupt processing is performed only when the power switch 257 is turned on, and processing for turning on the power switch is performed in step S7 and subsequent steps. Until the power switch is turned on, operations other than power switch interrupt processing are stopped to prevent the power battery from being consumed.

In step S1, when the power switch 257 is on, the process proceeds to step S3, and it is determined whether the attach / detach switch 259 is off. As described above, the attachment / detachment detection switch 259 is a switch that is turned off when the lens barrel 10 is removed from the camera body 20. If it is off, that is, if the lens barrel 10 is detached, the process proceeds to step S67 described later. This is because when the power switch lever of the camera body 20 is operated and the power is turned on with the lens barrel 10 detached, the same processing as when the lens is detached is performed. If it is determined in step S3 that the attach / detach switch 259 is on, the process proceeds to step S7 and subsequent steps to perform processing for turning on the power switch.

In step S7, the movable half mirror 201 is returned. This is because the movable half mirror 201 is in a position retracted from the photographing optical path when the power switch 257 is off (in the state of the two-dot chain line in FIG. 1), but the subject luminous flux from the lens barrel 10 is measured / photometrically measured. This is for guiding to the sensor 217 and performing photometry and distance measurement as necessary. In step S9, the dust removal operation in the dustproof filter 205 is performed. This is an operation in which a driving voltage is applied from the dustproof filter driving circuit 211 to the piezoelectric element 207 fixed to the dustproof filter 205, and dust and the like are removed by ultrasonic vibration as described above. Subsequently, the shutter driving circuit 213 performs an opening operation of the shutter 203 (S11).

As a result, the subject light flux that has passed through the movable half mirror 201 is not blocked by the shutter 203, so that a subject image is formed on the CCD 221. Using the image data picked up by the CCD 221, the through image conditions are initially set in order to start the through image display in which the subject image is displayed as a moving image on the rear liquid crystal monitor 26 (S13). The initial setting of the through image conditions is to set default values of the electronic shutter speed TV and ISO sensitivity SV of the CCD 221. In addition, the frame rate for displaying the through image is set (in this embodiment, 30 fps). Here, reading by the CCD 221 and processing of the image processing circuit 227, the video signal output circuit 233, the liquid crystal monitor driving circuit 235, and the like are performed so that the image is displayed on the rear liquid crystal monitor 26 and the like according to the set frame rate. Since the through image display is now ready, the start of the through image is instructed (S11). The through image display operation is controlled by the image processing circuit 227 in response to the start instruction.

Next, information such as a shooting mode for still image shooting such as a program shooting mode set by a mode dial (not shown) or a shooting mode such as a movie shooting mode, ISO sensitivity, a manually set shutter speed, an aperture value, etc. If there are, the photographing conditions are read (S17). Then, communication with the lens CPU 111 is performed, and various focal lengths, wide-side focal lengths, tele-side focal lengths, current set focus positions, close-up distances, open aperture values, and the like are set for the photographing lens of the lens barrel 10. The lens data is read (S19).

Subsequently, the image data of the moving image can be acquired with the exposure value EV that is the target appropriate exposure amount, and an image with appropriate brightness (lightness) is displayed on the rear liquid crystal monitor 26 and / or the liquid crystal 29 in the viewfinder. The through image condition is set (S21). In this step, conditions for the electronic shutter speed TV and sensitivity SV for driving the CCD 221 are set. Initially, the values initially set in step S13 are used, and the electronic shutter speed is set so that the target image brightness is obtained. Adjust TV and sensitivity SV. Details will be described later with reference to the flowchart of FIG.

Next, it progresses to step S23 and it is determined whether it is a reproduction | regeneration mode. This playback mode is a mode in which image data recorded on the recording medium 245 is read and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 when the playback button is operated. If the reproduction mode is set as a result of the determination, the process proceeds to step S41 to instruct the image processing circuit 227 to stop the through image display. Thereafter, after the shutter 203 is closed (S43), the image data recorded on the recording medium 245 is read, the image data is expanded by the compression / decompression circuit 231, and the video signal output circuit 233 and the liquid crystal monitor are driven. A still image or a moving image is reproduced and displayed on the rear liquid crystal monitor 26 and / or the viewfinder liquid crystal 29 via the circuit 235 (S45). If another manual operation such as half-pressing the release button is performed during the reproduction operation, the reproduction operation is terminated and the process returns to step S9 to repeat the above operation.

Returning to step S23, if the playback mode has not been set, the process proceeds to step S25 to determine whether the menu mode has been set. This determines whether the menu button is operated and the menu mode is set. As a result of the determination, if the menu mode is set, a through image stop instruction is output (S47) and a close command is output to the shutter 203 (S49) as in the case where the playback mode is set. Thereafter, a menu setting operation is performed (S51). Depending on the menu setting operation, various image quality priority modes and long-time mode selection for movie shooting, small capacity mode and image quality priority mode selection for still image shooting, white balance, ISO sensitivity setting, drive mode setting, etc. Can be set. Note that default values are preset for modes that can be selected during moving image shooting, modes that can be selected during still image shooting, and the like. When the menu setting operation is completed, the process returns to step S9, and the above operation is repeated.

Returning to step S25, if the result of determination is that the menu mode has not been set, processing proceeds to step S27, where it is determined whether the release button has been pressed halfway, that is, whether the 1R switch is on. As a result of the determination, if 1R is on, the process proceeds to step S53, and it is determined whether or not the shooting mode read in step S17 is the moving image mode. If the result of determination is that it is in moving image mode, the flow proceeds to step S55 to execute a moving image shooting operation subroutine. If it is not in moving image mode, that is, if it is still image mode, the flow proceeds to step S57. A shooting operation subroutine is executed. The subroutine for the moving image shooting operation will be described later using FIG. 6, and the subroutine for the still image shooting operation will be described later with reference to FIG. When the subroutine for moving image shooting operation ends, the process returns to step S17. When the subroutine for still image shooting operation ends, the process returns to step S9, and the above steps are repeated.

Returning to step S27, if the result of determination is that the 1R switch is off, processing proceeds to step S29, where it is determined whether the attachment / detachment detection switch 259 is off, as in step S3. When the lens barrel 10 is detached, a through image stop instruction is output (S61) and the shutter 203 is closed (S63), as in steps S41 and S43 in the reproduction mode. Thereafter, the retracting operation of the movable half mirror 201 is performed (S65). As described above, the retracting operation is performed by driving the motor to rotate the mirror cam 417 and rotating the mirror frame 403 to the position retracted from the photographing optical path by the biasing force of the opening spring 407 (FIG. 1). And the position of the chain double-dashed line in FIG.

When the retracting operation of the movable half mirror 201 is completed, or when it is determined in step S3 that the attachment / detachment detection switch 259 is off (that is, when the lens barrel 10 is detached), the process proceeds to step S67. It is determined whether the attachment / detachment detection switch 259 is on. In step S29, after detecting that the lens barrel 10 is detached, it is determined whether or not the lens barrel 10 is mounted again. As a result of the determination, if it is mounted, the process proceeds to step S71, and the movable half mirror 201 is returned. As described above, the mirror cam 417 is rotated by driving the motor, the locking lever 413 is rotated clockwise by the cam surface against the urging force of the opening spring 407, and the mirror frame. 403 is inserted in the optical path of the lenses 101a and 101b. When the return of the movable half mirror 201 is completed, the process returns to step S9 and the above-described steps are repeated.

Returning to step S67, if the attachment / detachment detection switch 259 is off, the process proceeds to step S69 to determine whether or not the power switch 257 is on. When the lens barrel 10 is detached and the power switch 257 is on, the mount opening remains open even when various operation buttons are operated. Therefore, from the viewpoint of preventing malfunction, the camera operation should not be performed. Yes. For this reason, in step S67, the lens barrel 10 is mounted, and in step S69, the standby state in which the determination of the operation state of the power switch lever is repeated. If it is determined in step S67 that the power switch 257 is off, the process returns to step S5 and enters a sleep state. If it is detected in step S67 that the lens barrel 10 remains detached, the determination in step S69 may be omitted, and the process may proceed to step S5 to enter the sleep state, or the process may proceed to step S9. Modifications such as performing an operation based on an operation by the operation button are possible.

Returning to step S29, if the result of determination is that the attachment / detachment detection switch 259 is on, that is, if the lens barrel 10 is mounted on the camera body, the routine proceeds to step 31, where it is determined whether or not the power switch 257 is on. If the result of determination is that it is on, processing returns to step S17 and the above steps are repeated. After the through image display is started in step S15, the subject luminous flux transmitted through the movable half mirror 201 is not blocked by the shutter 203 unless various operation buttons are operated in step S23 and the subsequent steps. The image data picked up by the CCD 221 is displayed as a moving image on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 as a moving image. If it is determined in step S31 that the power switch 257 is off, as in steps S41 and S43, the image processing circuit 227 is instructed to stop the live view display (S33), and the shutter 203 is closed. (S35). Thereafter, similarly to step S65 described above, after the retracting operation of the movable half mirror 201 is performed (S37), the process returns to step S5 and enters the sleep state.

Next, the through image condition setting subroutine of step S21 will be described with reference to FIG. When the through image condition setting subroutine is entered, first, a difference ΔEV between the target image brightness (predetermined value) and the image brightness at the previous imaging is calculated (S81). This is because, in the rear liquid crystal monitor 26 or the like, the exposure value EV is equivalent to the target image brightness on the screen (where EV = TV-SV (TV is the apex value of the electronic shutter speed, and SV is equivalent to the ISO sensitivity). The difference ΔEV between the apex value)) and the EV value when it was previously displayed on the rear liquid crystal monitor 26.

Subsequently, using the full aperture value AV0, the electronic shutter speed TV when the image displayed on the rear liquid crystal monitor 26 is acquired last time, and the image brightness difference ΔEV obtained in step S81, the appropriate EV value is calculated as AV0 + previous value. It is obtained from the arithmetic expression of TV-ΔEV (S83). Subsequent to this calculation, the next electronic shutter speed (next TV value) is calculated from the calculation formula of proper EV-AV0 using the proper EV value obtained in step S85 and the full aperture value AV0 (S85). Here, an instruction is output to the image sensor driving circuit 223 so as to control the CCD 221 with the next TV value obtained (S87). As described above, in this subroutine, the electronic shutter speed TV is changed in accordance with the difference (ΔEV) between the target image brightness and the previous image brightness, and is adjusted so that the image brightness is always constant. Further, when the calculated value of the next TV exceeds the set range, both the electronic shutter speed TV and the ISO sensitivity SV may be controlled.

Next, the still image shooting operation subroutine in step S57 will be described with reference to FIG. As described above, this subroutine is executed when the release button is pressed halfway when a still image shooting mode such as a normal program shooting mode is selected. First, the image processing circuit 227, the compression / decompression circuit 231 and the like are instructed to be in the still image mode (S91). As a result, these circuits perform processing suitable for still images.

Subsequently, a subroutine of phase difference AF1 for driving the photographing lens to the in-focus position based on the distance measurement operation and the distance measurement result is executed (S93). In the distance measurement, the subject light flux reflected by the movable half mirror 201 is received by the distance measurement sensor in the distance measurement / photometry sensor 217, and the distance measurement / photometry processing circuit 219 and the body CPU 229 are output using the output of the distance measurement sensor. And the like detect the focal shift amounts of the lenses 101a and 101b by the TTL phase difference method, and the lenses 101a and 101b are brought into focus by the optical system driving mechanism 107 via the lens CPU 111 based on the detected focal shift amounts. To drive.

This phase difference AF1 performs AF with higher accuracy than the subroutine of phase difference AF2 in step S189 described later. In general, the depth of focus d is set such that an allowable confusion circle is ε and an aperture value is F.
d = εF
It becomes. Here, the depth of focus d may be a positive value or a negative value. The phase difference AF in step S93 is performed with an open aperture, and the depth of focus d can be obtained if the allowable confusion circle is 30 μm, for example. In the phase difference AF1, the distance measurement operation and the lens driving toward the in-focus position are repeated until the focus shift enters the depth of focus d. Therefore, the smaller the allowable circle of confusion, the higher the accuracy of automatic focusing.

Next, photometry / exposure amount calculation is performed (S95). The subject luminous flux reflected by the movable half mirror 201 is also received by the photometry sensor of the distance measurement / photometry sensor 217 and processed by the distance measurement / photometry processing circuit 219, thereby detecting the subject brightness BV. The body CPU 229 obtains the exposure amount EV using the subject luminance BV, and further obtains the exposure conditions such as the shutter speed and the aperture according to the photographing mode. When the photometry / exposure amount calculation is completed, a through image condition setting is subsequently performed as in step S21 (S97).

When the through image condition setting is completed, it is next determined whether or not the release button has been fully pressed, that is, whether or not 2R is on (S99). As a result of the determination, if it is off, the process proceeds to step S101 to determine whether 1R is on. If the release button is half-pressed to jump to the still image shooting operation subroutine, and the release button remains half-pressed, a standby state is made in which repeat determination is made in steps S99 to S101. During this time, since the through image condition is set, the screen brightness of the through image displayed on the rear liquid crystal monitor 26 or the like is maintained even when the camera is pointed at a subject with different subject brightness while the release button is pressed halfway. It is adjusted to be appropriate. When the hand is released from the release button and 1R is turned off, the process returns to the power-on reset step S9.

Returning to step S99, if the result of determination is that the 2R switch is on, that is, if the release button is fully pressed, the operation moves to an imaging operation for acquiring a still image. First, in step S103, an instruction to stop the through image is output to the image processing circuit 227. This is because when moving the movable reflecting mirror 201 to the retracted position, a subject image incident on the CCD 221 is disturbed and a through image becomes unsightly on the rear liquid crystal monitor 26 and / or the liquid crystal 29 in the viewfinder. This is to prevent it.

Next, it is determined whether the recording mode for the recording medium 245 is the small capacity mode or the image quality priority mode is selected (S105). The small capacity mode is a mode for recording image data with a small capacity suitable for attaching an image to an e-mail or the like, and the image quality priority mode is a mode for recording image data to be a beautiful image suitable for printing. If it is determined that the mode is the small capacity mode, the process advances to step S129 to instruct the image processing circuit 229, the compression / decompression circuit 231 and the like to set the resolution to 320 * 240 and the compression rate to 1/10. send. On the other hand, if the image quality priority mode is determined as a result of the determination, the process proceeds to step S107, and the image processing circuit 229, the compression / decompression circuit 231 and the like are set so as to set the resolution to 3200 * 2400 and the compression rate to 1/2. Send instructions. Note that the resolution and the compression rate here are examples, and the resolution and the compression rate may be appropriately selected so that the image quality priority mode has a relatively high image quality.

Thereafter, similarly to step S65, the retracting operation of the movable half mirror 201 is performed (S109). In the present embodiment, since the high-quality image data is not required for acquiring and recording the image data in the small capacity mode, the subject luminous flux transmitted through the movable half mirror 201 is guided to the CCD 221. However, in the image quality priority mode, since high-quality image data is acquired and recorded, the movable half mirror 201 is retracted in order to avoid image quality degradation due to the movable half mirror 201.

When the instruction in step S129 or the retracting of the movable half mirror 201 in step S109 is completed, the lens CPU 111 is instructed to stop the aperture 103 to the set aperture value or the aperture value calculated in S95. Perform (S111). When the narrowing-down operation is completed, the CCD 221 performs an exposure operation for acquiring a still image (S113). That is, since the movable half mirror 201 is moved to the retracted position in the image quality priority mode, all the subject luminous fluxes that have passed through the lenses 101a and 101b are imaged on the CCD 221, and in the small capacity mode, the movable half mirror 201 is movable. The subject light flux that has passed through the half mirror 201 forms an image on the CCD 221.

In this state, the reset of the electronic shutter of the CCD 221 is released, and charge accumulation of the photoelectric conversion current of the subject image is started. When the exposure time set in advance or set in step S73 has elapsed, the electronic shutter of the CCD 221 stops the charge accumulation of the photoelectric conversion signal. In the exposure operation in step S113, the exposure time is controlled by the electronic shutter of the CCD 221. However, the present invention is not limited to this, and the exposure time can also be controlled by the shutter 203. In this case, it is necessary to once move the front and rear curtains of the shutter 203 to the initial positions before the start of the exposure operation.

Next, the shutter 203 is closed (S115), and an instruction to open the aperture 103 is output to the lens CPU 111 (S117). Further, the image signal stored in the CCD 221 is read, the image processing circuit 227 performs image processing, the compression / decompression circuit 231 performs signal compression and the like, and a still image file is generated (S119). Subsequently, the generated still image file is recorded on the recording medium 245 (S121). When the recording of the image data ends, it is determined in step S123 whether the 1R switch is on, that is, whether the release button is half-pressed.

When the 1R switch is turned off, it is determined whether or not the movable half mirror 201 is in a return state, that is, at a position where the movable half mirror 201 has entered the imaging optical path (S125). As described above, when the image quality priority mode is selected, the movable half mirror 201 is retracted in step S109. If the movable half mirror 201 has been retracted, the process proceeds to step S127, and the return operation of the movable half mirror 201 is performed in the same manner as in step S7. When the movable half mirror 201 has returned, or when the return operation in step S127 is completed, the routine returns to the power-on reset routine.

In the still image shooting operation subroutine of this embodiment, in the case of the image quality priority mode, the movable half mirror 201 is retracted from the shooting optical path during the shooting operation for acquiring a still image. For this reason, it is possible to avoid image degradation caused by the refractive index, thickness, etc. of the half mirror that occurs when passing through the movable half mirror 201. Further, the half mirror does not attenuate the subject light amount, and the subject light amount can be increased when acquiring a still image, so that shooting at a high shutter speed is possible. In the small-capacity mode, the movable half mirror 201 is not retracted while entering the photographing optical path, so that the shutter time lag can be shortened.

Next, the subroutine of the moving image shooting operation in step S55 will be described with reference to FIG. As described above, this subroutine is executed when the release button is pressed halfway while the moving image shooting mode is selected. First, the image processing circuit 227, the compression / decompression circuit 231 and the like are instructed to be in the moving image mode (S131). Thus, the image processing circuit 227 performs image processing suitable for moving images, and the compression / decompression circuit 231 performs compression suitable for moving images.

Subsequently, the phase difference AF1 is performed in the same manner as in step S93, and focusing is performed with high accuracy (S133). When the distance measurement / focus driving is completed, the through image condition is set in the same manner as in step S97, and the electronic shutter speed TV and the ISO sensitivity SV are set so that the target exposure value EV is obtained. In the still image shooting operation subroutine, photometry / exposure amount calculation is performed in step S95, but not in the moving image shooting operation. In the case of still image shooting, it is necessary to determine exposure conditions such as the shutter speed and the aperture value when shooting a single frame still image. In the case of moving image shooting, the through image condition setting in step S135 and that will be described later. This is because the moving image condition setting 1 in step S149 and the moving image condition setting 2 in steps S175 and S183 are adjusted so that the exposure value is aimed at moving image display, and the exposure condition setting is sufficient.

When the through image condition setting is completed, next, as in step S99, it is determined whether or not the release button is fully pressed, that is, whether or not 2R is on (S137). If the result of determination is that it is off, processing proceeds to step S139, where it is determined whether 1R is on. If the release button is half-pressed to jump to this moving image shooting operation subroutine and the release button remains half-pressed, steps S133 to S139 are looped to enter a standby state for repeated determination. During this time, the phase difference AF1 and the through image condition setting are performed. For this reason, even when the camera is pointed at a subject with different subject brightness while the release button is pressed halfway, the rear liquid crystal monitor 26 or the like is adjusted to have a constant screen brightness. Further, since the phase difference AF1 is repeatedly performed, the focus is automatically adjusted even when the framing is changed or the subject moves. When the hand is released from the release button and 1R is turned off, the process returns from step S139 to step S9 of the power-on reset.

If it is determined in step S137 that the 2R switch is on, that is, if the release button is fully pressed, the process proceeds to an imaging operation for moving image acquisition, and the process proceeds to step S141 to determine the recording mode. Do. If it is determined that the mode is the long time mode, the process proceeds to step S171, and an instruction is sent to the image processing circuit 229, the compression / decompression circuit 231 and the like to set the resolution to 160 * 120 and the compression level to 1/10. Here, the long-time mode is a mode in which a moving image is recorded for a long time with a reduced resolution and compression rate. Note that the resolution and the compression rate here are examples, and the resolution and the compression rate can be appropriately selected so that the image quality priority mode described later has a relatively high image quality.

When the instructions for the resolution and the like are finished, the lens CPU 111 is instructed to perform phase difference AF (S173). That is, in the long time mode, the recording time is more important than the image quality, so the movable half mirror 201 remains in the photographing optical path. For this reason, the subject light flux is guided to the distance measuring / photometric sensor 217 by the movable half mirror 201, and distance measurement by the phase difference AF can be performed, and the distance measurement by the phase difference AF and the focus position are repeatedly performed during moving image shooting. Driving.

Subsequently, moving image condition setting 2 for setting an electronic shutter speed TV for obtaining proper exposure in moving image shooting is performed (S175). Ranging in the phase difference AF mode is performed using triangulation using two peripheral light beams that pass through the photographing lens. For this reason, since the distance measurement accuracy is not sufficient in the narrowed-down state, when performing the phase difference AF in the long-time mode, the diaphragm is opened in the open state. Therefore, in the moving image condition setting 2 in step S175, an electronic shutter speed TV for obtaining appropriate exposure in the fully-open aperture state is obtained. The detailed flow of the moving image condition setting 2 will be described later with reference to FIG.

Returning to step S141, if it is determined that the image quality priority mode is set, the process proceeds to step S143 to set the resolution to 640 * 480 and the compression rate to 1/5 in order to perform high-quality moving image recording. In addition, an instruction is sent to the image processing circuit 229, the compression / decompression circuit 231 and the like. Note that the resolution and the compression ratio here are only examples, and as described above, the resolution and the compression rate are higher in the image quality priority mode than in the long-time mode described above. What is necessary is just to select a compression rate suitably. Subsequently, the lens CPU 111 is instructed to perform contrast AF (S145). The contrast AF mode is an AF mode in which information regarding whether or not to drive the lens, and information on the lens driving direction and the driving speed is transmitted to the body CPU 229. This contrast AF is not transmitted because drive amount information cannot be obtained.

When the contrast AF mode instruction ends, the movable half mirror is retracted in the same manner as in step S109 (S147). Since the image quality priority mode is a mode for shooting a moving image with high image quality, the movable half mirror 201 is retracted in order to avoid image quality degradation due to the movable half mirror 201.

Subsequently, the moving image condition setting 1 for setting the electronic shutter speed TV and aperture value AV for obtaining proper exposure in moving image shooting in the image quality priority mode is executed (S149). In the phase difference AF, since it is desirable to set to an open aperture, appropriate exposure is obtained only with the electronic shutter speed TV. However, since there is no such restriction in the contrast AF mode, the aperture value is adjusted together. For this reason, it is possible to perform control with a wide dynamic range with respect to the subject luminance. The detailed flow of the moving image condition setting 1 will be described later with reference to FIG. Next, the aperture value AV obtained in step S149 is transmitted to the lens CPU 111, and the aperture operation of the aperture 103 in the lens barrel 10 is performed (S151).

When the narrowing-down instruction ends or when the moving image condition setting 2 in step S175 ends, the process proceeds to step S153, where an instruction to start moving image recording is issued. When the moving image recording is started, the CCD 221 captures an image at the set electronic shutter speed TV, and the subject image signal output from the CCD 221 is processed by the image processing circuit 227 and compressed by JPEG for each frame by the compression / expansion circuit 231. The processed image data is stored in the SDRAM 238.

In step S155, it is determined whether the storage capacity of the SDRAM 238 used as the buffer memory is full. As a result of the determination, if it is not full, the process proceeds to step S181 to determine whether or not the 2R switch is on, that is, whether or not the release button is fully pressed by the photographer and movie shooting is continued. If the result of determination is that the 2R switch is on, processing advances to step S183, and the aforementioned moving picture condition setting 2 subroutine is executed. Here, only the electronic shutter speed TV is adjusted so that the framing is changed during moving image shooting in the image quality priority mode or the long-time mode, or even when the subject brightness changes, the appropriate exposure is obtained.

When the moving image condition setting 2 is completed, the recording mode is determined in the same manner as in step S141 (S185). If the image quality priority mode is determined as a result of the determination, the process advances to step S187 to perform known contrast AF. This is based on the subject image signal output from the CCD 221 and detects the in-focus state of the photographic lens by utilizing the fact that a high-frequency component increases in the subject image signal as the focus approaches, and based on this in-focus state information. This controls the driving of the taking lens.

On the other hand, if the recording mode is determined to be the long time mode, the process proceeds to step S189 to execute the phase difference AF2. This phase difference AF2 is less accurate than the phase difference AF1 in step S133 by setting the focusing accuracy to a focusing allowable confusion circle of, for example, about 60 μm. If the focusing accuracy is set to a high accuracy, tracking is performed according to changes in the subject image during moving body shooting, and the shooting lens is driven in small steps, so that the feeling of use is not necessarily good.

In this way, when the image quality priority mode is selected, shooting preparations are performed in steps S143 to S151, and when the long-time mode is selected, shooting preparations are performed in steps S171 to S175. In step S153, moving image recording is started, and the loop of steps S155 and S181 to S189 is repeated to record moving image data in the SDRAM 238. During this time, when the image quality priority mode is selected, image data with a high image quality (high resolution and low compression rate) is recorded with the movable half mirror 201 retracted, and automatic alignment is performed by contrast AF. I get burnt. On the other hand, when the long-time mode is selected, the subject image that has passed through the movable half mirror 201 is recorded with low-resolution and high-compression image data and is automatically focused by phase difference AF. .

Returning to steps S155 and S181, when the storage capacity of the SDRAM 238 in which image data is recorded is full, or when the 2R switch is turned off, that is, when the photographer releases the release button and stops shooting, the process proceeds to step S157 to record. Instruct to stop. Subsequently, an instruction to open the aperture is sent to the lens CPU 111 to open the aperture 103 (S159). Subsequently, a moving image file in MJPEG (Motion JPEG) format for moving images is generated based on the JPEG format image data for each frame stored in the SDRAM 238 (S161). The generated moving image file is recorded on the recording medium 245 via the recording medium control circuit 243 (S163).

Next, the retracted state of the movable half mirror 201 is determined (S165). If the result of determination is that it has been retracted, a return operation is performed in the same manner as in step S7 (S167). This is because when the image quality priority mode is selected, the movable half mirror 201 is retracted from the photographing optical path in step S147, and the movable half mirror 201 is restored at the end of the operation photographing operation. This is to quickly perform distance measurement and photometry by phase difference AF. If the result of determination in step S165 is that the movable half mirror 201 has returned, or when the movable half mirror return operation in step S167 has ended, the routine returns to step S9 in the power-on reset routine, and the above steps are repeated.

In the moving image shooting operation subroutine of the present embodiment, in the image quality priority mode, the movable half mirror 201 is retracted from the shooting optical path during the shooting operation for acquiring a moving image. For this reason, it is possible to avoid image degradation caused by the refractive index, thickness, etc. of the half mirror that occurs when passing through the movable half mirror 201. In addition, the half mirror does not attenuate the subject light amount, and the subject light amount can be increased when moving images are acquired, so that shooting at a high shutter speed is possible. In the image quality priority mode, since ranging and focusing drive are performed by contrast AF, a moving image in focus can be obtained.

Further, in the moving image shooting operation subroutine of the present embodiment, in the long time mode, it is possible to record a moving image for a long time by reducing the image quality. In addition, since the movable half mirror 201 is allowed to enter the photographing optical path, the reflected light of the subject light beam from the movable half mirror 201 is used to perform distance measurement and focusing drive by phase difference AF. Can be obtained. In particular, the TTL phase difference AF has an advantage of excellent tracking even when the subject distance changes greatly.

Next, the moving image condition setting 1 subroutine in step S149 will be described with reference to FIG. In this subroutine, the aperture value AV and the electronic shutter speed TV are set so that an appropriate exposure amount is obtained prior to moving image acquisition in the image quality priority mode. When this routine is entered, first, the difference (ΔEV) between the target image brightness (predetermined value) and the previous image brightness is calculated (S201). That is, the difference between the EV equivalent value that is the appropriate exposure amount and the brightness (EV of the exposure amount equivalent value) that was previously displayed on the rear liquid crystal monitor 26 is calculated. Next, this difference is subtracted from the previous exposure amount (that is, previous AV + previous TV) to obtain an appropriate exposure amount (appropriate EV) (S203).

Next, the next aperture value AV and electronic shutter speed TV are calculated from the obtained appropriate EV (S205). Since EV = AV + TV, AV and TV may be determined so that the added value of the aperture value AV and the electronic shutter speed TV becomes the appropriate EV obtained in step S203. The TV value calculated here is instructed to the image sensor driving circuit 223 (S207), and the electronic shutter speed of the CCD 221 is controlled. The obtained next aperture value AV is instructed to the lens CPU 111 in step S151 to control the aperture as described above. When the TV value setting is completed, the process returns to the routine below.

Next, the moving image condition setting 2 subroutine in steps S175 and S183 will be described with reference to FIG. In this subroutine, the electronic shutter speed TV is set so that an appropriate exposure amount is obtained without changing the aperture value AV. When this routine is entered, as in step S201, the difference between the target image brightness (predetermined value) and the brightness of the previous image (ΔEV) is calculated (S211). Subsequently, as in step S203, an appropriate EV value is obtained (S213). Thereafter, an electronic shutter speed TV for obtaining an appropriate EV value is obtained next time (S215). In the moving image condition setting 1, the aperture is distributed to the aperture AV and the electronic shutter speed TV so as to obtain an appropriate exposure amount. However, in the moving image condition setting 2, only the electronic shutter speed TV is changed without changing the aperture. Appropriate exposure is set. The imaging device driving circuit 223 is instructed to set the next TV value obtained here (S217).

In this way, in the present embodiment, control is performed so as to obtain an appropriate exposure amount by appropriately using the electronic shutter speed and the aperture value. That is, when TTL phase difference AF is performed, exposure control is performed with an open aperture value from the viewpoint of ensuring distance measurement accuracy, and when contrast AF is performed, an appropriate exposure amount is obtained before starting moving image shooting. Control is started by a combination of the aperture value and the electronic shutter speed.

Next, the flow of data processing relating to images in the present embodiment will be described. The image signal output from the CCD 221 is subjected to image processing (301) by the image processing circuit 227, and the contrast signal composed of the high frequency component at this time is sent to the body CPU 229 which is a sequence controller. Then, the image processing circuit 227 performs an image size changing process (303) using the processed image signal. This change process is performed according to the image size designated in steps S107, S129, S143, and S171.

The image data that has undergone the image size change processing is then sent to the compression / decompression circuit 231 for JPEG compression processing (305). The compression ratio here is the ratio instructed in steps S107, S129, S143, and S171. The image data subjected to JPEG compression processing is stored in the SDRAM 238 by single data accumulation (307) when still image shooting is selected. Then, the sequence controller creates a JPEG file based on the JPEG data stored in the SDRAM 238 (311).

On the other hand, when moving image shooting is selected, the image data subjected to the JPEG compression process (305) is sequentially stored in the SDRAM 238 in accordance with the start of moving image recording in step S153. Then, in response to the stop of moving image recording in step S157, storage of the image data in JPEG format is stopped, and the sequence controller performs moving image compression according to MJPEG, which is a compression format for moving images, and creates an MJPEG file (313). Next, an MJPEG file or a JPEG file is recorded on the recording medium 245 in accordance with the file recording in steps S121 and S163.

As mentioned above, although one Embodiment of this invention was described, the modification of this embodiment is demonstrated using FIG. In the moving image shooting operation of the embodiment, it is determined whether the recording mode is the image quality priority mode or the long-time mode (S141), and the image quality, the distance measuring method, and the position of the movable half mirror are determined. In the example, the shooting mode is changed depending on whether the shooting mode is the moving body mode or the still body mode. The moving body mode is a shooting mode suitable for shooting a moving body in which the subject is moving, and the still body mode is a shooting mode that does not particularly target such a subject.

This modification is the same as the embodiment except for steps S241 and S285 as compared with the moving image shooting operation subroutine shown in FIG. 6, and only the differences will be described. When this subroutine is entered and the process proceeds to step S241, it is determined whether the shooting mode is the moving body mode or the still body mode. As a result of the determination, in the case of the moving body mode, the process proceeds to S171 and the subsequent steps, and when acquiring the moving image, a low image quality condition is instructed as compared to the case of the still body mode. This is because when the subject moves, high-speed focus adjustment by phase difference AF is required, and focus followability of focus adjustment is more important than image quality. In addition, since the moving object's visual acuity is reduced, it is not required that the image quality be higher than that in the case of a still image. In addition, with the movable half mirror 201 still entering the photographing optical path, the distance measuring sensor receives the light flux of the subject from the photographing lens, and outputs an instruction to perform distance measurement and focusing drive by TTL phase difference AF. To do.

On the other hand, if it is determined in step S241 that the mode is still body mode, the process proceeds to step S143 and the subsequent steps, and conditions are instructed to obtain high image quality when moving images are acquired. In addition, the movable half mirror 201 is retracted from the photographing optical path to prevent image quality deterioration due to the movable half mirror 201. Also, a contrast AF instruction is issued so that the automatic focus adjustment operation can be performed even during moving image acquisition.

Next, also in step S285, the shooting mode is determined, and the process proceeds to contrast AF or phase difference AF2 depending on the determination result. In the moving body mode, the subject is moving, and even if the subject distance fluctuates greatly, the focus drive is performed by the phase difference AF with good tracking. In the still body mode, since the movable half mirror 201 is retracted from the photographing optical path in order to prioritize image quality, focusing driving is performed by contrast AF.

As described above, in the present embodiment and its modifications, the position of the movable half mirror 201 is changed according to the target image quality when recording a moving image. That is, when recording a high-quality moving image, the movable half mirror 201 is retracted from the photographing optical path to prevent the image from being deteriorated due to the movable half mirror 201. When high image quality is not required, the movable half mirror 201 is allowed to enter the imaging optical path to eliminate time for advancement and retreat, and to shorten the time lag until the start of imaging.

Further, in the present embodiment and its modifications, the position of the movable half mirror is changed according to the distance measuring method when recording a moving image. In other words, the phase difference AF is adopted when it is necessary to sufficiently follow even if the subject distance fluctuates, and the contrast AF is adopted otherwise.

Further, in the present embodiment and its modified examples, when recording a high-quality moving image, focusing is performed using contrast AF, and if not, focusing is performed using phase difference AF. This is very convenient because focusing is performed regardless of the image quality, even during moving image shooting.

Furthermore, in the present embodiment and its modifications, the combination of image quality, AF method, and arrangement of the movable half mirror 201 is automatically determined according to the shooting mode. That is, when the image quality priority mode is selected, the movable half mirror 201 is retracted from the photographing optical path to maintain high image quality, and is automatically set so that it can be focused with contrast AF. In addition, when the long time mode is selected, an image quality in which the recording time is more important than the image quality is selected, and the phase difference AF is set so that the subject can be followed for a long time. In addition, when the moving body mode is selected, the followability of the subject is emphasized, and the image quality and the AF method are selected.

As described above, in the present embodiment and the modification thereof, the influence on the image quality exerted by the movable half mirror 201 is examined, and the combination in which the resolution, the compression rate, and the distance measurement method are optimized according to the target shooting. Is set automatically, so it is very convenient to use.

Furthermore, in the present embodiment and its modifications, the position of the movable half mirror 201 is changed according to the target image quality even when a still image is taken. That is, when recording a high-quality still image, the movable half mirror 201 is retracted from the photographing optical path to prevent the image from being deteriorated due to the movable half mirror 201. When high image quality is not required, the movable half mirror 201 is allowed to enter the imaging optical path to eliminate time for advancement and retreat, and to shorten the time lag until the start of imaging.

Further, in the present embodiment and its modifications, the movable half mirror 201 is inserted in the photographing optical path when the camera is operated, and a part of the subject luminous flux is reflected to the distance measuring / photometric sensor 217, so that a through image display is performed. When the release button 21 is pressed halfway down and 1R is turned on, photometry and distance measurement can be performed immediately in parallel with the live view display.

In the present embodiment, the CCD 221 serving as the image sensor receives the transmitted light from the movable half mirror 201, and the distance measuring / photometric sensor 217 receives the reflected light from the movable half mirror 201. In addition, the CCD 221 may receive reflected light, and the distance measuring / photometric sensor 217 may receive transmitted light.

In the present embodiment, the present invention is applied to a general digital camera. However, the present invention is not limited thereto, and may be a digital camera in various devices such as a portable device, and may be attached to various devices such as a microscope and binoculars. Of course, the present invention can also be applied to a dedicated digital camera. The present invention can be applied to any camera that can record a shooting target as a moving image.

It is a block diagram which shows the whole structure of the electric system of the digital camera in one Embodiment to which this invention is applied. It is a disassembled perspective view which shows the structure of the movable reflective mirror in one Embodiment to which this invention is applied. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the through image condition setting in one Embodiment of this invention. It is a flowchart of the still image shooting operation in one embodiment of the present invention. It is a flowchart of the moving image shooting operation in one embodiment of the present invention. It is a flowchart of animation condition setting 1 in one embodiment of the present invention. It is a flowchart of the moving image condition setting 2 in one Embodiment of this invention. It is a flowchart which shows the process of the data in one Embodiment of this invention. It is a flowchart which shows the modification of the moving image shooting operation | movement in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens barrel 20 Camera main body 26 Back surface liquid crystal monitor 29 Liquid crystal monitor 101a, 101b in finder Lens 103 Diaphragm 111 Lens CPU
201 Movable half mirror 203 Shutter 215 Movable mirror drive mechanism 217 Distance / photometric sensor 221 CCD
223 Image sensor driving circuit 227 Image processing circuit 229 Body CPU
231 Compression / decompression circuit 238 SDRAM
241 Communication circuit 243 Recording medium control circuit 245 Recording medium 257 Power switch

Claims (10)

Imaging means for receiving a subject luminous flux that has passed through the photographing lens and outputting a subject image signal;
Recording means for recording a moving image of a subject based on the subject image signal;
A half mirror that can move back and forth in the optical path
In the state where the half mirror has advanced into the photographing optical path, the defocus amount of the photographing lens is detected based on the subject light beam reflected by the half mirror, and the focusing operation of the photographing lens is performed based on the detection result. First focusing means for performing;
Second focus adjusting means for performing a focusing operation of the photographing lens based on contrast information of the subject image signal in a state where the half mirror is retracted from the photographing optical path;
A first moving image recording mode in which the half mirror is disposed in the photographing optical path, moving image recording is performed while performing the first focus adjustment focusing operation, the half mirror is retracted from the photographing optical path, and the second Selection means capable of selectively setting a second moving image recording mode in which moving image recording is performed while performing a focusing operation by the focus adjusting means;
It has
A digital camera capable of recording a moving image, wherein the image quality in the second moving image recording mode is higher than the image quality in the first moving image recording mode.   The digital camera capable of moving image recording according to claim 1, wherein the second moving image recording mode has a higher resolution than the first moving image recording mode.   The digital camera capable of moving image recording according to claim 1, wherein the second moving image recording mode has a lower compression rate than the first moving image recording mode.   The digital camera capable of moving image recording according to claim 1, wherein the first moving image recording mode is selected in accordance with a shooting mode suitable for moving body shooting.   2. The digital camera capable of moving image recording according to claim 1, wherein the first moving image recording mode is selected in accordance with a shooting mode in which shooting time is more important than image quality. Imaging means for receiving a subject luminous flux that has passed through the photographing lens and outputting a subject image signal;
Recording means for recording a moving image of a subject based on the subject image signal;
A half mirror that can be moved back and forth in the imaging optical path and guides a part of the subject luminous flux to the phase difference AF sensor in the imaging optical path;
It has
A digital camera capable of recording a moving image, wherein whether or not the half mirror is caused to enter the photographing optical path is determined according to an image quality condition of moving image recording by the recording means.   7. The digital camera capable of recording a moving image according to claim 6, wherein an image quality when the half mirror is in the photographing optical path is set lower than an image quality when the half mirror is retracted from the photographing optical path. . Imaging means for receiving a subject luminous flux that has passed through the photographing lens and outputting a subject image signal;
Recording means for recording a subject image based on the subject image signal;
A half mirror that can be moved back and forth in the shooting optical path,
A shooting mode setting means for setting a shooting mode;
Comprising
A digital camera characterized in that when the shooting mode set by the shooting mode setting means gives priority to image quality, the half mirror is retracted from the shooting optical path of the shooting lens when shooting by the imaging means. . In a state where the half mirror has advanced into the photographing optical path, the defocus amount of the photographing lens is detected based on the subject light beam reflected by the half mirror, and the focusing operation of the photographing lens is performed based on the detection result. First focusing means for performing;
Second focus adjusting means for performing a focusing operation of the photographing lens based on contrast information of the subject image signal in a state where the half mirror is retracted from the photographing optical path;
Comprising
9. The digital camera according to claim 8, wherein when shooting is performed with the half mirror retracted, a focusing operation is performed by the second focus adjusting unit.   9. The digital camera according to claim 8, further comprising recording means for recording image data based on a subject image signal from the imaging means, wherein the recording means selectively records a moving image or a still image. .