JP2007322983A - Photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographing apparatus configured to reduce a release time lag, in which a half mirror is arranged in a photographing optical path, and which is capable of displaying a through-image. <P>SOLUTION: The movable half mirror is made movable between an enter position in the photographing optical path and a retreat position outside the photographing optical path, and in reply to the half-depression of a release button, a photographing preparation operation is started, and the movable half mirror is made to enter the photographing optical path (S65), a range finding operation is performed by a range finding sensor (S69), after the range finding operation, the movable half mirror is retreated outside the photographing optical path (S71). The movable half mirror retreating operation is already finished before the start (S79) of the photographing operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a photographing apparatus having a through image display function, and more specifically, a so-called through image display function (also referred to as a live view display function or an electronic viewfinder function) for displaying an image acquired by an image sensor as a moving image on a display device. The present invention relates to a photographing apparatus.

In conventional photographing apparatuses such as digital cameras, the observation of subject images has been performed with an optical finder. Recently, however, the optical finder has been eliminated, and an imaging device provided for recording subject image data instead. Is also used for display. That is, there are an increasing number of images having a through image display function for displaying an image acquired by an image sensor on a display device such as a liquid crystal monitor for observing a subject image.

As a digital camera having such a through image display function, for example, Japanese Patent Application Laid-Open No. H10-228707 obtains a subject image to an imaging device by retracting a movable mirror from a photographing optical path and fully opening a focal plane shutter. An interchangeable lens camera that continuously displays a subject image on a liquid crystal monitor is disclosed. However, in Patent Document 1, a TTL (Trough The Lens) phase difference AF (Auto Focus) generally adopted in a conventional camera is used in order to retract the movable mirror out of the photographing optical path during live view display. There is a problem that can not be done.
JP 2002-369042 A

Therefore, Patent Document 2 proposes a digital camera in which a movable mirror is configured by a half mirror, and a subject light beam that has passed through a photographing optical system is guided to both an image sensor and a phase difference AF sensor. According to this configuration, phase difference AF is also possible while displaying a through image, and the above-described problem can be solved.
Japanese Patent Laid-Open No. 2002-6208

However, when a configuration in which a half mirror is arranged in a photographing optical path as in Patent Document 2 is applied to a digital camera, the following problem may occur. In other words, the movable half mirror is retracted from the imaging optical path at the time of shooting so that all of the subject luminous flux from the imaging lens is guided to the image sensor, so that an operation time is required to retract the movable half mirror. Release time lag will increase.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a photographing apparatus capable of reducing the release time lag.

In order to achieve the above object, a photographing apparatus according to a first aspect of the present invention is capable of receiving a subject luminous flux through a photographing lens and outputting a subject image signal, and can advance and retreat in the optical path of the imaging means. In the optical path, a moving image is displayed on the display device based on a half mirror that reflects a part of the subject luminous flux, a driving unit that drives the half mirror, and a subject image signal that is repeatedly output from the imaging unit. A through image means, and a distance measuring means for receiving a subject light beam reflected by the half mirror when the half mirror is in the optical path and detecting a focus state of the photographing lens; The driving means causes the half mirror to enter the optical path in conjunction with the distance measuring operation by the distance measuring means.

In the photographing apparatus according to a second invention, in the first invention, the driving means retracts the half mirror out of the optical path in conjunction with the end of the distance measuring operation by the distance measuring means.
Further, in the photographing apparatus according to the third invention, in the first invention, the brightness of the image displayed on the display device is substantially the same regardless of whether or not the half mirror has entered the optical path. To be constant.
Furthermore, the imaging device according to a fourth aspect of the present invention is the imaging apparatus according to the first aspect, wherein the imaging means is in accordance with the transmittance of the half mirror in conjunction with the half mirror entering the optical path. Increase imaging gain.
Furthermore, in the photographing apparatus according to the fifth invention, in the fourth invention, the imaging means lowers the imaging gain in conjunction with the retraction of the half mirror from the optical path.
Further, a photographing apparatus according to a sixth aspect of the present invention includes, in the first aspect, a photographing preparation operation member that instructs a photographing preparation operation, and the driving means responds to the photographing preparation operation instruction by the half mirror. Execute the save operation.

In order to achieve the above object, a photographing apparatus according to a seventh aspect of the present invention is a half mirror capable of moving back and forth in the optical path of a photographing lens and reflecting a part of a subject luminous flux from the photographing lens in the optical path, Driving means for driving the half mirror in and out of the imaging optical path, an instruction for an imaging preparation operation, an operation member for instructing an imaging operation, and the operation when the imaging preparation operation is instructed by the operation member Means for driving the half mirror into the optical path by means, and a controller for retracting the half mirror from the optical path by the driving means before the imaging preparation operation is commanded.

According to an eighth aspect of the present invention, there is provided a photographing apparatus according to the seventh aspect, further comprising distance measuring means for receiving a subject light beam reflected by the half mirror and detecting a focus state of the photographing lens. The means measures the distance by the distance measuring means when the half mirror is in the optical path.
According to a ninth aspect of the present invention, in the eighth aspect, the control means retracts the half mirror from the optical path when the distance measuring operation by the distance measuring means is completed.
Furthermore, an imaging device according to a tenth invention is the imaging device according to the seventh invention, wherein the imaging device receives the subject light beam through the imaging lens and outputs a subject image signal, and the subject repeatedly output from the imaging device. Through image means for displaying a moving image on the display device based on the image signal is provided.
An imaging apparatus according to an eleventh aspect of the present invention is the imaging apparatus according to the seventh aspect, further comprising an amplifying unit that amplifies the subject image signal from the imaging unit, and when the half mirror advances and retreats in the imaging optical path. The gain is changed in accordance with the change in the amount of subject light reaching the imaging means.

According to the present invention, since the driving means for allowing the half mirror to enter the optical path in conjunction with the distance measuring operation by the distance measuring means is provided, it is possible to provide an imaging apparatus capable of reducing the release time lag.

Hereinafter, a preferred embodiment using a digital camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is an external perspective view of a digital camera according to an embodiment of the present invention as viewed from the back. This camera is composed of a camera body 20 and a lens barrel 10 as an interchangeable lens. 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, 101b, etc. (see FIG. 2) 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 a communication contact 300 (see FIG. 2). Also, the attachment / detachment state can be detected by an attachment / detachment detection switch 259 (see FIG. 2) provided in the camera body 20.

On the upper surface of the camera body 20, a release button 21, a mode dial 22, a power switch lever 23, a control dial 24, and the like are arranged. The release button 21 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 it is turned on, a photographing operation for capturing image data of a subject image is executed based on the output of a CCD (Charge Coupled Devices) 221 (see FIG. 2) as an image sensor.

The mode dial 22 is an operation member that is configured to be rotatable. By matching a picture display or symbol representing a shooting mode provided on the mode dial 22 with an index, a full-auto shooting mode (AUTO) or a program shooting mode is set. (P), aperture priority shooting mode (A), shutter speed priority shooting mode (S), manual shooting mode (M), portrait shooting mode, landscape shooting mode, macro shooting mode, sports shooting mode, night scene shooting mode, etc. Each shooting mode can be selected. The power switch lever 23 is an operation member for turning on / off the power supply of the digital camera, and is configured to be rotatable at two positions, on / off. The control dial 24 is an operation member configured to be rotatable, and a desired set value, mode, or the like can be selected by rotating the control dial 24 on an information display screen or the like.

On the back of the camera body 20, a rear liquid crystal monitor 26, a playback button 27, a menu button 28, a cross button 30, an OK button 31, and a viewfinder eyepiece 33 are arranged. The rear liquid crystal monitor 26 is a display device for displaying a subject image as a through image for observation, reproducing and displaying a photographed subject image, and displaying camera information and menus. Any liquid crystal display can be used as long as it can perform these displays. Note that the camera body 20 may be configured to freely change the angle. The viewfinder eyepiece 33 is an eyepiece window for observing a subject image, and an in-finder liquid crystal monitor 29 described later is disposed therein, and the subject image can be observed through the finder eyepiece 33. Yes. The playback button 27 is an operation button for instructing to display a subject image recorded after shooting on the rear liquid crystal monitor 26. In accordance with the operation of the playback button 27, the image data of the subject stored in the later-described SDRAM 238 or the recording medium 245 in the compression mode such as JPEG is expanded and then displayed on the rear liquid crystal monitor 26.

The cross button 30 is an operation member for instructing the movement of the cursor in the two-dimensional direction of the X direction and the Y direction on the rear liquid crystal monitor 26, and for displaying the subject image recorded on the recording medium 245. Also used to select playback images. In addition to providing four buttons for up, down, left, and right, it is also possible to replace with a switch that can be operated in a two-dimensional direction, such as a switch that can detect the operation direction in two dimensions, such as a touch switch. is there. The OK button 31 is an operation member for confirming various items selected by the cross button 30, the control dial 24, or the like. The menu button 28 is a button for switching to a menu mode for setting various modes of the digital camera. When the menu mode is selected by operating the menu button 28, a menu screen is displayed on the rear liquid crystal monitor 26. . The menu screen has a plurality of hierarchical structures. Various items are selected with the cross-shaped button 30, and selection is determined by operating the OK button 31.

The release button 21, the power switch lever 23, the playback button 27, the menu button 28, the cross button 30, and the OK button 31 are all linked to the on / off switch. Signals generated in response to the operation of the operation buttons linked to these on / off switches and the operation members such as the mode dial 22 and the control dial 24 are detected by the switch in an ASIC (Application Specific Integrated Circuit) 262. It is transmitted to the circuit 253 (see FIG. 2).

Next, referring to FIG. 2, an overall configuration mainly including an electric system of the digital camera will be described.
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 aperture driving mechanism 109 to control the aperture value.

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 path of the lenses 101a and 101b (the position indicated by the solid line in FIG. 2), a part (for example, 30%) of the subject luminous flux is reflected, and the camera body 20 Is guided to a distance measuring sensor 217 provided at the bottom of the. Further, the remainder (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 at a retracted position (a position indicated by a two-dot chain line in FIG. 2) 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. In the present embodiment, the reflectance and transmittance of the movable half mirror are 30% and 70%, respectively, but are not limited to this ratio.

A distance measuring 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 sensor 217 is a sensor for measuring a distance by a TTL phase difference method. The output of the distance measuring sensor 217 is sent to the distance measuring circuit 219. The distance measuring circuit 219 measures the amount of focus shift of the subject image formed by the lenses 101 and 101b based on the output of the distance measuring sensor 217.

A focal plane type shutter 203 for controlling the exposure time and shielding the CCD 221 is disposed behind the movable half mirror 201 and on the optical axis of the lenses 101a and 101b and on the photographing optical path. The shutter 203 is driven and controlled by a shutter drive mechanism 213. A dust-proof 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. Has been. A CCD 221 serving as an image sensor is disposed behind the optical low-pass filter 210, and subjects images formed by the lenses 101a and 101b are photoelectrically converted into electric signals. 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 the image pickup device. However, the present invention is not limited to this, and it is needless to say that a two-dimensional image pickup device such as a CMOS (Complementary Metal Oxide 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, and the image processing circuit 227 performs digital amplification (digital gain adjustment processing) of digital image data, color correction, gamma (γ) correction, contrast correction, monochrome / color mode. Various image processing such as processing and through image processing 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 image data stored in the SDRAM 238 by JPEG or TIFF. Note that image compression is not limited to JPEG or TIFF, 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 where it can be observed by the photographer through the viewfinder eyepiece 33, and like the rear liquid crystal monitor 26, other liquid crystal display devices may be used. Note that only the rear liquid crystal monitor 26 may be used for observation of the subject image, and the finder eyepiece 33 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 dust filter driving circuit 211, the shutter driving mechanism 213, the movable mirror driving mechanism 215, the distance measuring processing circuit 219, and the image sensor driving circuit 223 is connected to the body CPU 229 or the like via the data bus 261. Controls data input / output 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.

A power switch 257 that is turned on / off in conjunction with a power switch lever 23 for controlling the power supply of the camera body 20 and the lens barrel 10, and a switch that detects the first stroke and the second stroke of the shutter release button 21. A switch linked to the playback button 27 for instructing the playback mode, a switch linked to the cross button 30 for instructing the movement of the cursor on the screen of the rear liquid crystal monitor 26, and a switch linked to the mode dial 22 for instructing the shooting mode. In addition, various switches 255 such as an OK switch linked to an OK button 31 for determining each mode and the like, and the attachment / detachment detection switch 259 are connected to the data bus 261 via the switch detection circuit 253. The structure of the attachment / detachment detection switch 259 will be described later with reference to FIG.

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 403a, and the rotation shaft 201a in FIG. 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. 3) in the imaging optical path includes a mirror cam 417, a locking lever 413, and the like. The retracting means for driving the movable half mirror 201 to the retracted position outside the photographing optical path (the position indicated by the two-dot chain line in FIG. 3) 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 unlocking 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.

FIG. 6 is a block diagram showing the configuration of the attachment / detachment detection switch 259 that detects the attachment / detachment state of the camera body 20 and the lens barrel 10. The interlocking pin 137 provided in the mount portion to which the lens barrel 10 of the camera body 20 is attached is urged in a direction protruding from the camera body 20 by the pressing spring 138. One end of the interlocking pin 137 on the camera body side is in contact with the lens attaching / detaching switch 139, and the lens attaching / detaching switch 139 is spring-biased in the opening direction. Reference numeral 131 denotes a lens side mount portion of the lens barrel 10.

Since the attachment / detachment detection switch 259 is configured as described above, when the lens barrel 10 is attached to the camera body 20, the interlocking pin 137 is moved by the lens-side mount portion 131 as shown in FIG. The lens attachment / detachment switch 139 is turned on, that is, the attachment / detachment detection switch 259 is turned on. On the other hand, when the lens barrel 10 is removed from the camera body, as shown in FIG. 6B, the interlocking pin 137 protrudes to the right side of the drawing by the urging force of the pressing spring 138. Off, that is, the attachment / detachment detection switch 259 is turned off. In addition, the detection of the attachment / detachment state of the lens barrel 10 is not limited to the mechanical detection switch as in the present embodiment, and may be, for example, a photoelectric detection switch using a photosensor, a method by communication with the lens CPU 111, There are various methods such as detection of the energized state of the two contact points in contact with the lens barrel 10.

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowcharts shown in FIGS. When the power-on reset flow shown in FIG. 4 is entered, 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 S5, 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 S51 described later. This is because when the power switch lever 23 of the camera body 20 is operated and the power is turned on while the lens barrel 10 is 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 dust removal operation in the dustproof filter 205 is performed. In this operation, a driving voltage is applied from the dust filter driving circuit 211 to the piezoelectric element 207 fixed to the dust filter 205, and dust and the like are removed by ultrasonic waves as described above.

Subsequently, the shutter driving circuit 213 performs an opening operation of the shutter 203 (S9). Since the movable half mirror 201 is in the retracted position, the subject light beam is not blocked by the shutter 203 by opening the shutter 203, and a subject image is formed on the CCD 221. Using the image data picked up by the CCD 221, the rear liquid crystal monitor 26 is instructed to start a through image display for displaying a subject image as a moving image (S 11). The through image display operation is controlled by the image processing circuit 227 in response to the start instruction.

Next, if there is information such as the shooting mode set by the mode dial 22 or the like, ISO sensitivity, manually set shutter speed or aperture value, those shooting conditions are read (S13). Then, the subject brightness is obtained based on the output from the CCD 221, the exposure amount is calculated, and exposure control values such as the shutter speed and the aperture value are calculated according to the shooting mode and shooting conditions using this exposure amount (S15). Further, through image display setting is performed using a photometric value, an exposure amount, and the like (S17). In this step, in order to set the electronic shutter speed and sensitivity conditions for driving the CCD 221, using the photometry / exposure calculation result obtained in step S15 or the previous display image, the rear liquid crystal monitor 26 and / or Alternatively, calculation and setting for displaying an image of appropriate brightness (brightness) on the liquid crystal 29 in the finder is performed.

Next, it progresses to step S19 and it is determined whether it is a reproduction | regeneration mode. This playback mode is a mode in which when the playback button 27 is operated, still 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. If the reproduction mode is set as a result of the determination, the process proceeds to step S31 to instruct the image processing circuit 227 to stop the through image display. Thereafter, after closing the shutter 203 (S33), the still image data recorded on the recording medium 245 is read out, the image data is expanded by the compression / expansion circuit 231, and the video signal output circuit 233 and the liquid crystal monitor are read out. The still image is reproduced and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 via the drive circuit 235 (S35). If another manual operation such as half-pressing the release button 21 is performed during the reproduction operation, the reproduction operation is terminated and the process returns to step S7 to repeat the above-described operation.

Returning to step S19, if the playback mode has not been set, the process proceeds to step S21 to determine whether the menu mode has been set. This determines whether the menu button 28 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 (S37) and a close command is output to the shutter 203 (S39), as in the case where the playback mode is set. Thereafter, a menu setting operation is performed (S41). Various setting operations such as white balance, ISO sensitivity setting, and drive mode setting can be performed by the menu setting operation. When the menu setting operation is completed, the process returns to step S7, and the above operation is repeated.

Returning to step S21, if the result of determination is that the menu mode has not been set, processing proceeds to step S23, where it is determined whether the release button 21 has been pressed halfway, that is, whether the 1R switch is on. If the result of determination is that 1R is on, processing advances to step S43, and a shooting operation subroutine for shooting preparation and shooting is executed. Details of this subroutine will be described later with reference to FIG. When the photographing operation subroutine ends, the process returns to step S7 and the above-described steps are repeated.

Returning to step S23, if the result of determination is that the 1R switch is off, processing proceeds to step S25, where it is determined whether the attachment / detachment detection switch 259 is off, as in step S2. When the lens barrel 10 is detached, a through image stop instruction is output (S45) and the shutter 203 is closed (S47), as in steps S31 and S33 in the reproduction mode.

When the closing operation of the shutter 203 is completed, or when it is determined in step S2 that the attachment / detachment detection switch 259 is off (that is, when the lens barrel 10 is detached), the process proceeds to step S51, and attachment / detachment detection is performed. It is determined whether the switch 259 is on. In step S25, after detecting that the lens barrel 10 is detached, it is determined whether or not the lens barrel 10 is attached again. If the attachment / detachment switch 259 is on, that is, if the lens barrel 10 is attached, the process returns to step S7 and the above steps are repeated.

If the attachment / detachment detection switch 259 is off, the process advances to step S53 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, the lens barrel 10 is attached in step S51 and the standby state in which the determination of the operation state of the power switch lever 23 is repeated in step S53. If it is determined in step S53 that the power switch 257 is off, the process returns to step S5 and enters a sleep state. In step S51, when it is detected that the lens barrel 10 remains detached, the determination in step S53 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 S25, if the result of determination is that the attachment / detachment detection switch 259 is on, that is, if the lens barrel 10 is attached to the camera body, the routine proceeds to step S27, 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 S13 and the above steps are repeated. In step S11, after the through image display is started, the subject light flux that has passed through the movable half mirror 201 is not blocked by the shutter 203 unless various operation buttons are operated in step S19 and 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 S27 that the power switch 257 is off, as in steps S31 and S33, the image processing circuit 227 is instructed to stop displaying the through image (S28), and the shutter 203 is closed. (S29). Thereafter, similarly to step S49 described above, after the retracting operation of the movable half mirror 201 is performed (S30), the process returns to step S5 to enter the sleep state.

Next, the shooting operation subroutine of step S43 will be described with reference to FIG. As described above, this subroutine is executed when the release button 21 is half-pressed. First, the movable half mirror 201 is caused to enter the optical path of the photographic lens (lenses 101a and 101b) (S65). 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 photographing lens. Subsequently, the imaging gain of the output of the CCD 221 is increased and corrected (S67). This is to compensate for the fact that the movable half mirror 201 is inserted in the optical path of the photographic lens to reduce the amount of light, and thus the display screen on the rear liquid crystal monitor 26 and / or the viewfinder liquid crystal 29 becomes dark. It is. The correction of the imaging gain is performed in the image processing circuit 227 so that the imaging gain is increased according to the transmittance of the movable half mirror 201. For example, if the transmittance of the half mirror is 50%, the amount of light reaching the CCD 221 is halved, so the imaging gain may be increased by one step.

Next, ranging and automatic focus adjustment are performed (S69). This is because in step S65, the movable half mirror 201 is inserted in the optical path, and a part of the subject light beam is reflected by the distance measuring sensor 217. Therefore, the distance measuring circuit 219, the body CPU 229, etc. Detects the focus shift amount of the lenses 101a and 101b by the TTL phase difference method, and drives the lenses 101a and 101b to the focus position by the optical system drive mechanism 107 via the lens CPU 111 based on the detected focus shift amount. To do. Note that the photometry / exposure amount calculation is not performed in this subroutine because it is performed in step S13, but based on the output of the CCD 221 in the same manner as in step S13 in response to half-pressing of the release button 21. Of course, it is possible to go. Of course, a photometric sensor may be disposed at a position where the reflected light from the movable half mirror 201 is received, and the output of this photometric sensor may be used.

Next, since the distance measuring operation is completed, the retracting operation of the movable half mirror 201 is performed (S71). 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 retracted position from the photographing optical path by the biasing force of the opening spring 407 (FIG. 2). And the position of the chain double-dashed line in FIG. 3). Further, since the movable half mirror 201 is retracted, the imaging gain is corrected (S73). As described above, the amount by which the subject light amount has decreased due to the insertion of the movable half mirror 201 in the optical path is corrected in step S67. However, in step S71, since the movable half mirror 201 is retracted and the amount of light of the subject increases, correction is performed so that the imaging gain is decreased in this step. The correction amount in this case is determined in consideration of the transmittance of the movable half mirror 201. In addition, if the through image is disturbed during the entering / retreating operation of the movable half mirror 201 in step S65 and step S71, the through image may be temporarily fixed.

Next, it is determined whether or not the release button 21 is fully pressed, that is, whether or not 2R is on (S75). If the result of determination is that it is off, processing advances to step S77 to determine whether 1R is on. If the release button 21 is half-pressed to jump to this shooting operation subroutine and the release button 21 remains half-pressed, a standby state is made in which the determination is repeated in steps S75 and S77. When the hand is released from the release button 21 and 1R is turned off, the process returns to the power-on reset step S9.

Returning to step S75, if the result of determination is that the 2R switch is on, that is, if the release button 21 is fully pressed, the operation moves to an imaging operation for acquiring a still image. First, in step S79, a through image stop instruction is output to the image processing circuit 227. This is due to the movement of the movable half mirror 201 to the retracted position and the opening / closing operation of the shutter 203 during the acquisition of the still image, causing the subject image incident on the CCD 221 to be disturbed, and in the rear liquid crystal monitor 26 and / or the liquid crystal 29 in the viewfinder. This is to prevent the through image from becoming unsightly.

Subsequently, the aperture driving mechanism 109 performs the aperture operation of the aperture 103 to the set aperture value or the aperture value calculated in step S15 via the lens CPU 111. When the narrowing-down operation is completed, an exposure operation by the CCD 221 is then performed (S85). That is, since the movable half mirror 201 has moved to the retracted position, all of the subject luminous flux that has passed through the lenses 101 a and 101 b 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 S85, 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.

Subsequently, the shutter 203 is closed (S87), and an instruction to open the aperture 103 is output to the lens CPU 111 (S89). Further, the image signal stored in the CCD 221 is read (S91), and image processing is performed by the image processing circuit 227 or the like (S93). After processing such as signal compression in the compression / decompression circuit 231, image data is recorded on the recording medium 245 (S95). When the recording of the image data is finished, it is determined in step S97 whether the 1R switch is on, that is, whether the release button 21 is half pressed. When the 1R switch is turned off, the routine returns to the power-on reset routine.

In the power-on reset and photographing operation routine of the present embodiment, in a normal state, the movable half mirror 201 remains retracted from the optical path of the photographing lenses (lenses 101a and 101b). When the power-on operation is started, the shutter 203 is opened in step 9 and the subject image is directly formed on the CCD 221, so that the through image display is displayed on the rear liquid crystal monitor 26 or the like using the subject image signal from the CCD 221. The subject image can be observed. In this state, when distance measurement is necessary, the movable half mirror 201 is caused to enter the optical path so that the subject luminous flux is guided to the distance measurement sensor 217. When the distance measurement is completed, the movable half mirror 201 is retracted from the optical path, so that the shutter time lag caused by retracting the movable half mirror 201 can be eliminated before the photographing operation in step S79 and subsequent steps.

In the present embodiment, the movable half mirror 201 is retracted during normal live view display, so that the amount of light transmitted through the movable half mirror 201 does not decrease, and display on a display device such as the rear liquid crystal monitor 26 is possible. Can be brightened. Further, since the movable half mirror 201 is also retracted from the photographing optical path when acquiring a still image at the time of photographing, the amount of subject light can be increased, and photographing at a high shutter speed is possible.

In this embodiment, when the movable half mirror 201 enters the optical path during live view display (S65), the amount of subject light decreases when passing through the movable half mirror 201, so that the imaging gain is corrected. Like to do. For this reason, the brightness of the through image display screen can be kept constant. Similarly, when the movable half mirror 201 is retracted from the optical path, the imaging gain is corrected. Furthermore, since this gain correction is a correction amount considering the transmittance of the movable half mirror 201, accurate correction can be performed. In addition to adjusting the imaging gain, the brightness of the captured image can be corrected by correcting the brightness of the captured image by the image processing circuit 227 or simply changing the display conditions of the liquid crystal monitor 26. May be adjusted to be substantially constant.

In the present embodiment, since the movable half mirror 201 is normally retracted from the optical path of the photographing lens in the present embodiment, when the lens barrel 10 is removed and the mount portion is in the open state, the user or the like can move from the mount opening portion. Even if a cleaning tool or the like is to be inserted, the movable half mirror 201 is in the retracted state, so there is no possibility that the movable half mirror 201 is damaged or a fingerprint is attached.

In the present embodiment, the camera ranging operation is started by pressing the release button 21 halfway. As a modification, when the continuous ranging mode is selected, steps S65 to S73 may be repeated at predetermined time intervals. In this case, continuous distance measurement may be performed only while the release button 21 is half-pressed.

In the present embodiment, the CCD 221 serving as an image sensor receives the transmitted light from the movable half mirror 201, and the distance measuring sensor 217 receives the reflected light from the movable half mirror 201. May be configured to receive reflected light and the ranging sensor 217 to receive transmitted light.

In the present embodiment, the present invention is applied to a general digital camera. However, the present invention is not limited to this, and may be a photographing device in various devices such as a portable device, and is equipped with a bellows, an extension tube, or the like. Of course, the present invention can also be applied to a dedicated camera attached to various devices such as a microscope and binoculars.

It is the external appearance perspective view which looked at the digital camera in one Embodiment of this invention from the back surface. 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 perspective view which shows the components structure of the movable half mirror in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this invention. 6 is a flowchart of a shooting operation according to an embodiment of the present invention. It is a figure which shows the structure of the attachment / detachment detection switch in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens barrel 20 Camera main body 21 Release button 23 Power switch lever 26 Back surface liquid crystal monitor 29 In-finder liquid crystal monitor 33 Viewfinder eyepiece 101a, 101b Lens 103 Diaphragm 111 Lens CPU
201 Movable half mirror 203 Shutter 205 Dustproof filter 207 Piezoelectric element 209 Infrared cut filter 210 Optical low-pass filter 215 Movable mirror drive mechanism 217 Distance sensor 219 Distance processing circuit 221 CCD
227 Image processing circuit 229 Body CPU
253 Switch detection circuit 255 Various switches 257 Power switch 259 Detachment detection switch 261 Data bus 401 Half mirror 403 Mirror frame

Claims (11)

Imaging means for receiving a subject luminous flux through a photographing lens and outputting a subject image signal;
A half mirror capable of moving back and forth in the optical path of the imaging means and reflecting a part of the subject luminous flux in the optical path;
Driving means for driving the half mirror;
Based on the subject image signal repeatedly output from the imaging means, a through image means for displaying a moving image on the display device;
Ranging means for receiving a subject light beam reflected by the half mirror and detecting a focus state of the photographing lens when the half mirror is in the optical path;
It has
The imaging apparatus according to claim 1, wherein the driving means causes the half mirror to enter the optical path in conjunction with a distance measuring operation by the distance measuring means.   2. The photographing apparatus according to claim 1, wherein the driving means retracts the half mirror out of the optical path in conjunction with the end of the distance measuring operation by the distance measuring means.   2. The photographing apparatus according to claim 1, wherein the brightness of an image displayed on the display device is substantially constant regardless of whether or not the half mirror has entered the optical path. .   The imaging apparatus according to claim 1, wherein the imaging unit increases the imaging gain according to the transmittance of the half mirror in conjunction with the half mirror entering the optical path.   The imaging apparatus according to claim 4, wherein the imaging unit lowers the imaging gain in conjunction with the half mirror being retracted from the optical path.   2. The photographing apparatus according to claim 1, further comprising a photographing preparation operation member for instructing a photographing preparation operation, wherein the driving unit executes a retraction operation of the half mirror in response to the photographing preparation operation command. . A half mirror capable of moving back and forth in the optical path of the photographic lens and reflecting a part of the subject luminous flux from the photographic lens in the optical path;
Driving means for driving the half mirror in and out of the photographing optical path;
A command for shooting preparation operation and an operation member for commanding shooting operation
When the shooting preparation operation is commanded by the operating member, the driving means drives the half mirror into the optical path, and the driving means drives the half mirror to the optical path before the shooting preparation operation is commanded. Control means for evacuation from within,
An imaging apparatus comprising: Ranging means for detecting the light flux of the subject reflected by the half mirror and detecting the focus state of the photographing lens is provided, and the control means measures the measurement when the half mirror is in the optical path. 8. The photographing apparatus according to claim 7, wherein distance measurement is performed by a distance unit. 9. The photographing apparatus according to claim 8, wherein the control means retracts the half mirror from the optical path when the distance measuring operation by the distance measuring means is completed. An imaging unit that receives a subject luminous flux through the photographing lens and outputs a subject image signal, and a through image unit that displays a moving image on a display device based on the subject image signal repeatedly output from the imaging unit. The imaging device according to claim 7, wherein: Amplifying means for amplifying the subject image signal from the imaging means, and the gain is changed according to a change in the amount of subject light reaching the imaging means when the half mirror advances and retreats in the imaging optical path. The imaging device according to claim 7.