JP2007279529A - Digital single-lens reflex camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital single-lens reflex camera capable of achieving accurate focusing even when through image operation is performed. <P>SOLUTION: When an AF instruction button is depressed during B mode display for displaying through images on the basis of an output from an image recording main CCD, preparation for shifting the B mode display to A mode display for displaying through images is performed on the basis of an output from an intra-finder CCD, so that the B mode display is shifted to the A mode display; respective steps are successively executed from a step S1, and in steps S35, S37, operation is branched to a step S39. After executing range finding and focus adjustment, the A mode display is returned to the B mode display again. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a digital single-lens reflex camera having a through image display function, and more specifically, a so-called through image display function (live view display function and electronic viewfinder function) that displays an image repeatedly acquired by an image sensor as a moving image on a display device. A digital single-lens reflex camera.

In conventional cameras, the subject image is observed with an optical viewfinder. However, recent compact digital cameras abolish the viewfinder optical system together with the optical viewfinder, and continuously acquire images acquired by the image sensor. More and more, so-called through image display functions for displaying on a display device such as a liquid crystal monitor have been increasing.

Such a live view display function is effective, for example, during macro photography because no parallax occurs. For this reason, various examples mounted on a digital single lens reflex camera have been proposed. For example, the optical viewfinder display mode and the electronic viewfinder display mode can be selected. When the electronic viewfinder display mode is selected, the movable mirror is retracted from the photographing optical path and the focal plane shutter is fully opened to guide the subject image to the image sensor. There has been proposed a digital single-lens reflex camera in which subject images obtained thereby are continuously displayed on a liquid crystal monitor (Patent Document 1).
JP 2002-369042 A

By the way, in this type of live view function, the movable mirror has to be retracted out of the photographing optical path, so that the TTL phase difference AF generally adopted in the conventional single-lens reflex camera cannot be performed, and manual operation is not possible. However, there is a limitation that the photographing lens must be focused (so-called manual focus). Manual focus can be used to achieve focus according to the photographer's intentions. However, if the subject conditions are low, such as low brightness, low contrast, or small objects, a small LCD monitor In many cases, the conventional autofocus can perform more accurate focus adjustment than the manual focus while viewing the display device. As described above, when the output of a plurality of image sensors is selectively displayed as a through image, accurate focusing may be difficult if auto focus cannot be used when any one of the image sensors is selected.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a digital single-lens reflex camera capable of accurate focusing even when a through image is being performed.

In order to achieve the above object, a digital single-lens reflex camera according to a first aspect of the present invention is a photographic lens, a first position retracted out of the optical path of the photographic lens, and a first lens that guides a subject luminous flux to the optical viewfinder in the optical path. Mirror means movable to position 2, and when the mirror means is in the second position, an autofocus operation is performed by detecting the focus state of the photographing lens based on the subject light beam transmitted through the mirror means. And a first through image in which the subject image captured by the image recording image sensor is continuously displayed on the display device in a state where the mirror means is moved to the first position. In a state where the display means and the mirror means are moved to the second position, a subject image picked up by an image pickup device arranged in the finder is continuously displayed on the display device. When a predetermined operation member different from the release button is operated during the live view display operation of the live view display means and the live view display means of the first live view display means, the mirror means is moved to the second position. And a control means for executing a through image display operation by the second through image display means and an autofocus operation by the autofocus means.

According to a second aspect of the present invention, there is provided a digital single-lens reflex camera having a photographing lens, a first position retracted outside the optical path of the photographing lens, and a second position for guiding a subject luminous flux to the optical viewfinder in the optical path. A movable mirror means, an autofocus means for detecting a focus state of the photographing lens based on a subject light beam incident through the mirror means, and performing an autofocus operation; and The first through image display means for continuously displaying the subject image picked up by the image recording image pickup element on the display device in the state of being moved to the position, and the through image display by the first through image display means When a predetermined pointing member different from the release button is operated during operation, the mirror means is moved to the first position, and then the autofocus means Comprising a control means for executing the Okasu operation.

Furthermore, a digital single-lens reflex camera according to a third aspect of the present invention is a photographic lens, an autofocus unit that detects a focus state of the photographic lens and executes an autofocus operation, and a subject imaged by an image recording image sensor. A first through image display means for continuously displaying images on the display device, and a predetermined indicating member different from the release button is operated during the through image display operation by the first through image display means. And a control means for executing an autofocus operation by the autofocus means.
Furthermore, an electronic camera according to a fourth aspect of the present invention selectively switches between the photographing lens and the outputs of the first and second image sensors, and displays an image repeatedly acquired by the image sensor as a moving image on the display device. An image display means, an operation member for instructing a recording preparation operation for the subject image based on the output of the first image sensor, and the through image display based on the output of the first or second image sensor. An autofocus unit that detects the focus state of the photographing lens during a display operation by the unit and executes an autofocus operation, and a predetermined image different from the release button during a through image display in which the autofocus unit is inoperative When the instruction member is operated, a control means for switching to another through image display means for setting the autofocus means to an operating state is provided.

In the digital single-lens reflex camera of the present invention, when a predetermined pointing member different from the release button is operated during the live view display operation by the first live view display means, the autofocus operation by the autofocus means is executed. Because of this, it is possible to provide a digital single-lens reflex camera capable of accurate focusing even when a through image is being performed.

Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view of a digital single-lens reflex camera to which the present invention is applied. This single-lens reflex camera is composed of a camera body 20 and a lens barrel 10 as an interchangeable lens. The lens barrel 10 is detachably attached to the front mounting portion of the camera body 20. In the present embodiment, the lens barrel 10 and the camera body 20 are configured separately and are electrically connected via a communication contact (not shown). However, the lens barrel 10 and the camera body 20 are integrally configured. It is also possible to do.

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 the subject image is executed based on the output of the image sensor.

The mode dial 22 is an operation member configured to be rotatable, and a program mode, an aperture priority mode, a shutter priority mode, a portrait by matching a symbol or picture display representing a shooting mode (not shown) on the mode dial with an index. Shooting modes such as mode and auto mode can be selected. The power switch lever 23 is an operation member for turning on / off the power of the digital single-lens reflex camera, and is configured to be rotatable at two positions, on and off. The control dial 24 is an operation member for setting photographing information such as a shutter speed, an aperture value, a sensitivity, and a correction value, and various setting values can be changed by a rotating operation.

On the back of the camera body 20, there are a liquid crystal monitor 26, a playback button 27, a menu button 28, a cross key 30, an OK button 31, a viewfinder 33, a through image switching button 34, a display switching button 35, a preview button 36, and an AF instruction button 37. Is arranged. The playback button 27 is an operation button for instructing display of a subject image recorded on the liquid crystal monitor 26 after shooting. The subject image data stored in a later-described SDRAM 237 or recording medium 245 in a compression mode such as JPEG is expanded and displayed. The cross key 30 is an operation member for instructing movement of the cursor in the two-dimensional direction of the X direction and the Y direction on the liquid crystal monitor 26. The OK button 31 is an operation member for confirming various items selected by the cross key 30 or the like. The menu button 28 is a button for switching to the menu mode. When the menu mode is selected by operating the button 28, a menu screen is displayed on the liquid crystal monitor 26. The menu screen has a plurality of hierarchical structures, and various items are selected with the cross key 30 and the selection is determined by operating the OK button 31.

The display switching button 35 is an operation member for switching to a through image display for displaying a subject image on the liquid crystal monitor 26 based on the output of the image sensor. As will be described later in the through image display, the digital single-lens reflex camera of the present embodiment has two types of A mode display and B mode display, and the through image switching button 34 is an operation button for switching between these two mode displays. . The preview button 36 is an operation button for issuing a command for narrowing the aperture of the photographing lens from the open state in order to confirm the depth of focus when observing the subject image. The AF instruction button 37 is an operation button for detecting the focus state of the photographing lens and instructing execution of an autofocus operation. As will be described later, when the AF instruction button 37 is operated in the B mode display in which the subject image is displayed on the display device based on the output of the recording image pickup device, the distance measurement and the focus based on the distance measurement are performed. Align. These playback button 27, menu button 24, display switching button 35, preview button 36, and AF instruction button 37 are all linked to an on / off switch, and a signal generated in response to the operation of the operation button will be described later. (Application Specific Integrated Circuit). The 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. Although not shown, the angle with respect to the camera body 20 can be freely changed. The eyepiece 33 is an eyepiece of the finder optical system, and the photographer can look into the eyepiece 33 and check the subject image.

FIG. 2 is a block diagram showing a schematic optical configuration of the digital single-lens reflex camera according to the embodiment of the present invention.
A first reflecting mirror 201 is disposed in the camera body 20 on the optical axis of the photographing lens 101 disposed in the lens barrel 10. The first reflecting mirror 201 captures a subject image at a position inclined by 45 degrees with respect to the optical axis of the photographic lens 101 in order to reflect the subject luminous flux to the finder optical system, and a subject image (a main CCD (Charge Coupled Device) described later). 221), it can be rotated to a position retracted from the photographing optical path. The rotation axis 201a of the first reflection mirror 201 is along the height direction of the camera body 20, and can be rotated around the symbol R. The first reflecting mirror 201 totally reflects the subject luminous flux to the right as viewed from the front surface of the camera body 20. In the present embodiment, the light is totally reflected to the right. However, the present invention is not limited to this, and the reflection direction of the subject light flux is most appropriate in terms of the arrangement of the mechanism members and optical members, both above and to the left of the camera body. You may choose to Moreover, although the movable mirror is used as the optical path changing member, the present invention is not limited to this, and any member that can change the optical path, such as a liquid crystal mirror that can be electrically switched between a transmission state and a reflection state, may be used.

A screen mat 205 is disposed on the reflection optical axis of the first reflection mirror 201, and a second reflection mirror 271 formed of a half mirror is disposed behind the screen mat 205. The screen mat 205 is a mat surface for forming an image of a subject light flux by the photographing lens 101, and is disposed at a position equivalent to the main CCD 221 (see FIG. 3) at a distance from the first reflection mirror 201. The second reflecting mirror 271 reflects a part of the subject luminous flux above the camera body 20, and the remaining subject luminous flux passes through the second reflecting mirror 271 and enters the photometric sensor 281 disposed behind. The photometric sensor 281 is a 7 × 7 divided photometric sensor for measuring subject luminance, and is connected to an input / output circuit 239 in the ASIC 263.

A third reflection mirror 273 is disposed on the reflection optical axis of the second reflection mirror 271, and the subject luminous flux is totally reflected by the third reflection mirror 273 on the upper left side of the camera body 20. A fourth reflection mirror 275 configured with a half mirror is disposed on the reflection optical axis of the third reflection mirror 273. On the transmission optical axis of the fourth reflection mirror 275, an imaging lens 277 and a CCD 279 in the finder as a two-dimensional imaging device are arranged. The in-viewfinder CCD 279 converts the subject image formed on the screen mat 205 into a photoelectric signal and outputs it to the CCD drive circuit 283 (FIG. 3). The fourth reflecting mirror 275 reflects the remaining subject light beam behind the camera body 20, and an eyepiece lens 209 is disposed on the reflected optical axis. The subject luminous flux reflected by the fourth reflecting mirror is observed as a subject image by the photographer E through the eyepiece 209 and the finder 33 (FIG. 1).

FIG. 3 is a block diagram showing the overall configuration of the digital single-lens reflex camera according to the present embodiment.
Inside the lens barrel 10, photographing lenses 101a and 101b for adjusting the focal length and adjusting the focal length, and a diaphragm 103 for adjusting the aperture amount are arranged. The lens 101 a and the lens 101 b are driven by the lens driving mechanism 107, and the diaphragm 103 is driven by the diaphragm driving mechanism 109. These lens driving mechanism 107 and diaphragm driving mechanism 109 are each connected to a lens CPU 111, and this lens CPU 111 is connected to the camera body 20 via a communication contact (not shown). The lens CPU 111 controls the lens barrel 10 and controls the lens driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to control the aperture value.

The first reflection mirror 201 described above is disposed in the camera body 20, and on the right side of the first reflection mirror 201 (in FIG. 3, the drawing is above the first reflection mirror 201). The above-described screen mat 205 is arranged to form a subject image, and the second reflecting mirror 271, the third reflecting mirror 273, and the fourth reflecting mirror 275 are arranged behind the screen mat 205, and the second A photometric sensor 281 is disposed behind the reflection mirror 271, and an imaging lens 277 and a viewfinder CCD 279 (abbreviated as “F CCD” in FIG. 3) are disposed behind the fourth reflection mirror 275. An eyepiece lens 209 is disposed on the reflection optical axis of the fourth reflection mirror 275.

Near the center of the first reflection mirror 201 described above, a half mirror is formed, and on the back surface of the first reflection mirror 201, a sub mirror 203 for reflecting a subject light beam transmitted through the half mirror portion is provided. . The sub mirror 203 is rotatable with respect to the first reflecting mirror 201. When the first reflecting mirror 201 is retracted from the photographing optical path and the subject light flux is incident on the main CCD 221, the sub mirror 203 is positioned so as to cover the half mirror portion. When the first reflecting mirror 201 is in the subject image observation position as shown in the drawing, the first reflecting mirror 201 is in a position perpendicular to the first reflecting mirror 201. The first reflecting mirror 201 is driven by a mirror driving mechanism 219. In addition, a phase difference type distance measuring circuit 217 including a distance measuring sensor is disposed on the reflected optical path of the sub mirror 203, and this circuit detects a focus shift amount of a subject image formed by the lenses 101a and 101b. It is a circuit for doing.

A focal plane type shutter 213 for controlling the exposure time is disposed behind the first reflecting mirror 201, and the shutter 213 is driven and controlled by a shutter driving mechanism 215. A main CCD 221 serving as a two-dimensional imaging device is disposed behind the shutter 213, and subjects images formed by the lenses 101a and 101b are photoelectrically converted into electric signals. 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 main CCD 221 is connected to a CCD drive circuit 223, and the analog / digital conversion (AD conversion) is performed by the CCD drive circuit 223. The CCD drive circuit 223 receives control from a later-described sequence controller (hereinafter referred to as “body CPU”) 229 via the input / output circuit 239, performs on / off control of the power of the main CCD 221, and performs imaging timing of the main CCD 221. To adjust the variation with the output of the CCD 279 in the finder, and amplify the photoelectric conversion signal (gain adjustment). A CCD drive circuit 283 described later has a similar function. The in-viewfinder CCD 279 is an image pickup device that photoelectrically converts a subject image formed on the screen mat 205, and may be an image pickup device such as a CMOS like the main CCD 221, and the number of pixels is only used for observation of the subject image. The number may be smaller than that of the main CCD 221. The in-finder CCD 279 is connected to a CCD drive circuit 283, and the CCD drive circuit 283 performs analog-digital conversion (AD conversion).

The CCD drive circuit 223 and the CCD drive circuit 283 are connected to a CCD switching circuit 285, and this CCD switching circuit 285 is controlled to selectively output any one of the CCDs by a switching control line from the input / output circuit 239. . The CCD switching circuit 285 is connected to the image processing circuit 227 via the CCD interface 225. The image processing circuit 227 performs various types of image processing such as color correction, gamma (γ) correction, contrast correction, monochrome / color mode processing, and through image processing. The image processing circuit 227 is connected to the data bus 261 in the ASIC 263. In addition to the image processing circuit 227, the data bus 261 includes a body CPU 229, a compression circuit 231, a flash memory control circuit 233, and an SDRAM (Synchronous Dynamic Random Access).
Memory) control circuit 236, input / output circuit 239, communication circuit 241, recording medium control circuit 243, video signal output circuit 247, and switch detection circuit 253 are connected.

The body CPU 229 connected to the data bus 261 controls the flow of the digital single lens reflex camera. A compression circuit 231 connected to the data bus 261 is a circuit for compressing image data or the like stored in an SDRAM 237 described later with JPEG. Note that image compression is not limited to JPEG, and other compression methods can be applied. The flash memory control circuit 233 connected to the data bus 261 is connected to the flash memory 235. The flash memory 235 stores a program for controlling the flow of the electronic camera, and the body CPU 229 The electronic camera is controlled according to the program stored in H.235. Note that the flash memory 235 is an electrically rewritable nonvolatile memory. The SDRAM 237 is connected to the data bus 261 via the SDRAM control circuit 236, and the SDRAM 237 temporarily stores the image information processed by the image processing circuit 227 or the image information compressed by the compression circuit 231. It is a memory for.

The input / output circuit 239 for connecting the shutter driving mechanism 215, distance measuring circuit 217, mirror driving mechanism 219, CCD driving circuit 223, photometric sensor 281, CCD driving circuit 283, and CCD switching circuit 285 is connected via the data bus 261. Controls data input / output with each circuit such as the body CPU 229. A communication circuit 241 connected to the lens CPU 111 via a communication contact (not shown) 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 includes a rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), a memory stick (registered trademark), or a hard disk drive (HD). The camera body 20 is detachable.

The video signal output circuit 247 connected to the data bus 261 is connected to the liquid crystal monitor 26 via the liquid crystal monitor drive circuit 249. The video signal output circuit 247 is a circuit for converting image data stored in the SDRAM 237 or the recording medium 245 into a video signal to be displayed on the liquid crystal monitor 26. The liquid crystal monitor 26 is arranged on the back surface of the camera body 20 as shown in FIG. 1, but it is not limited to the back surface as long as it can be observed by the photographer. . A switch for detecting the first stroke and the second stroke of the release button 21, a mode dial 22, a power switch 23, a control dial 24, a playback button 27, a menu button 28, a cross key 30, an OK button 31, and a through image switching button 34 Various switches 255 (abbreviated as various SWs in FIG. 3) including a preview button 36, a lens detection switch <not shown> and the like are connected to the data bus 261 via the switch detection circuit 253.

Next, a hierarchical structure of display / operation modes of the digital single-lens reflex camera according to the present embodiment will be described with reference to FIG.
There are three main display / operation modes: information display M100, A mode display M200, and B mode display M300. The information display M100 is initially set in a state where the camera body 20 is turned on. In this information display mode, basic information is displayed for shooting by the camera, and an information display screen for shooting mode, shutter speed, aperture, AF mode, flash, pixel count, etc. is displayed on the liquid crystal monitor 26. Is displayed. Shooting modes such as a program mode and a shutter speed priority mode are set by rotating the mode dial 22. Items such as sensitivity, shutter speed, aperture value, correction value, and number of pixels are selected by operating the cross key 30 on the information display screen, and numerical values are set by operating the control dial 24.

The A mode display M200 is a mode in which the subject image formed on the screen mat 205 is photoelectrically converted by the in-finder CCD 279 and the observation subject image is displayed on the liquid crystal monitor 26 based on the photoelectric conversion signal. In this mode, the subject luminous flux is guided to the distance measuring circuit 217 via the sub mirror 203 provided in the first reflecting mirror 201, so that the automatic focus detection operation can be performed together with the observation of the subject image. In the screen display on the liquid crystal monitor 26, as shown in FIG. 8A, “A” (see reference numeral 305) is displayed at the lower left of the screen to indicate the A mode display. In this mode, the AF frame 303 engraved on the screen mat 205 can also be visually recognized.

In the B mode display M300, the first reflecting mirror 201 is retracted from the photographing optical path, the shutter 213 is opened, the subject luminous flux is directly formed on the main CCD 221, and the subject image is converted into a photoelectric conversion signal. In this mode, an object image for observation is displayed on the liquid crystal monitor 26 based on the signal. In this mode, since the subject light flux is directly received by the main CCD 221 without using the half mirror in the finder optical system, the reduction in the amount of light reaching the CCD 221 can be prevented, and a subject image can be sufficiently obtained even for a low-luminance subject. Can be displayed. Note that, in the B mode display M300, the autofocus is essentially inoperative. That is, since the first reflecting mirror 201 is retracted, the automatic focus detection is not activated, and focusing in this case is performed manually. As shown in FIG. 8B, “B” (see reference numeral 307) is displayed at the lower left of the screen of the liquid crystal monitor 26 to indicate that the mode is B mode display. In this mode, since the distance measurement by the distance measurement circuit 217 is impossible, the AF frame is not displayed unlike the A mode display. Of course, the symbols for indicating the A mode display and the B mode display are not limited to “A” and “B”, but may be symbols, characters, pictograms, etc. such as “main CCD” and “in-finder CCD”. . However, as will be described later, by operating the AF instruction button 37, the first reflecting mirror 201 is rotated and moved to a position where the subject luminous flux is reflected by the CCD 279 in the finder, so that the distance measuring circuit 217 becomes operable. An automatic focusing operation is performed.

As described above, when the camera body 20 is turned on, the information display M100 is initialized. Switching from the information display M100 to the A mode display M200 or the B mode display M300 is performed by operating the display switching button 35. In this case, when the display switching button 35 is operated, the display mode is switched to the A mode display M200 or the B mode display M300 set most recently. At the time of shipment from the factory, if the A mode display is set as a default value (of course, B mode display is also possible), when the display switching button 35 is first operated, the mode is switched to the A mode display M200 and displayed again. When the switch button 35 is operated, the display returns to the information display M100. When the through image display switching button 34 is operated when the A mode display M200 is set, the mode is switched to the B mode display M300. When the through image display switching button 34 is operated again in this state, the display returns to the A mode display M200. . When the display switching button 35 is operated in the B mode display M300, the display returns to the information display M100. That is, switching from the information display M100 to the A mode display M200 or the B mode display M300 is performed by operating the display switching button 35 to shift to the most recently set mode, and the A mode display M200 and the B mode display M300. Switching between them is performed by a through image display switching button 34.

Here, the fact that either the A mode display M200 or the B mode display M300 is set is stored in a non-illustrated nonvolatile memory, so that the memory is retained even if the power of the camera body 20 is turned off. Is done. However, it goes without saying that the display may be reset to either the A mode display or the B mode display in accordance with the power on. As a special case, when the lens detection switch (not shown) detects that the lens barrel 10 has been removed from the camera body 20, the B mode display M300 is switched to the information display M100.

As described above, in this embodiment, the light amount of the subject light flux is reduced, but the A mode display capable of performing the automatic focus adjustment and the automatic focus adjustment are disabled, but the light amount of the subject light flux is not reduced and is reduced. The B mode display capable of sufficiently displaying the subject image even with the brightness is switched by a simple operation.

Next, the lower hierarchy of the information display M100 will be described. In the information display M100, when the release button 21 is half-pressed (1R on), photographing preparation operations such as photometry and distance measurement are performed (M120), and when the release button 21 is fully pressed (2R on), the main The output of the CCD 221 is read, and the photographing operation C for recording the recording image data on the recording medium 245 is executed (M121). When the shooting operation is finished and the release button 21 is half-pressed (1R off), the display returns to the information display M100. When the menu button 28 is turned on, a menu screen for setting card setting, drive mode, flash correction, etc. appears (M130). It can be determined by operating the cross key 30 on this screen to move the cursor, select a desired item, and press the OK button 31 (M131). When menu button 28 or OK button 31 is turned on from menu display M130, it is possible to return to information display M100. Furthermore, on the screen of the information display M100, the mode dial 22, the control dial 24, and the cross key 30 can be operated to set the desired mode / value (M140).

Next, moving to the lower hierarchy of the A mode display M200, first, when the release button 21 is half-pressed and 1R is turned on, shooting preparation is performed in the same manner as the shooting preparation operation M120 (M220). When pressed and 2R is turned on, a shooting operation A is performed (M221). When the menu button 28 is turned on, a menu screen appears (M230). In this state, the cross key 30 is operated to move the cursor, select an item, determine a desired item with the OK button 31, and return to the menu display M230 (M231). When the menu button 28 or the OK button 31 is turned on in this display state, the screen returns to the A mode display M200.

Next, moving to the lower level of the B mode display M300, first, when the menu button 28 is pressed and turned on in the B mode display M300, the menu is displayed (M310). Here, when the cross key 30 is operated (M311) and the desired item is determined by the OK button 31, the display returns to the menu display M310. From the menu display, it is possible to return to the B mode display M300 by turning on the menu button 28 or the OK button 31. Even in the B mode display state, even if the release button 21 is half-pressed, the first reflecting mirror is in the retracted state and the shutter is in the open state. When turned on, the photographing operation B for recording the recording image data on the recording medium 245 is executed based on the image signal from the main CCD (M320).

Next, the A mode display M200 shown in FIG. 4 will be described with reference to the flowchart shown in FIG.
As described above, when the display switching button 35 is turned on, an A mode display operation for displaying a subject image based on an output from the CCD 279 in the finder is performed. First, in order to determine the driving condition of the in-viewfinder CCD 279, photometric / exposure amount calculation (that is, the subject luminance value, shutter speed and sensitivity) is performed based on the output of the photometric sensor 281 in step S1. Next, the CCD 279 in the finder is selected (S3), and power is supplied to it (S5). Subsequently, in order to set the electronic shutter speed and sensitivity conditions for driving the CCD, the through image condition setting 1 subroutine is executed using the photometry / exposure amount calculation result obtained in step S1 (S7). By executing this subroutine, an image with appropriate brightness (brightness) can be displayed on the liquid crystal monitor 26. Details of this subroutine will be described later with reference to FIG. When the through image condition setting 1 is completed, the A mode display is started (S9). The through image display operation is controlled by the image processing circuit 227 in response to the start instruction.

Next, similarly to step S2, photometry / exposure amount calculation is performed again (S11), and the calculated exposure amount is displayed (S13). Subsequently, in order to keep the brightness of the live view display on the liquid crystal monitor 26 appropriately, a live view condition setting 2 subroutine is executed (S15). Since the through image condition setting 1 in step S7 was before the through image display on the liquid crystal monitor 26, it was performed based on the output of the photometric sensor 281, but in the through image condition setting 2, the target brightness and the previous imaging The electronic shutter speed and sensitivity at the next imaging are determined from the screen brightness and the difference based on the result. Here, the brightness is a value corresponding to a weighted average value of each pixel output of the CCD, for example. Thereafter, it is determined whether or not the release button 21 is half-pressed, that is, whether 1R is turned on (S21).

If the result of determination is that 1R is on, photometry / exposure amount calculation for use in exposure control during shooting operation is performed (S23), and a ranging / focus adjustment subroutine is executed (S25). The distance measurement / focus adjustment subroutine calculates the focus shift amount of the photographing lens 101 based on the output of the distance measurement circuit 217, calculates the lens drive amount based on the focus shift amount, and drives the lens via the lens CPU 111. The mechanism 107 is driven to perform focusing. Subsequently, it is determined whether or not the release button 21 is fully pressed, that is, whether or not 2R is turned on. If it is off, it is determined whether or not the release button 21 is half-pressed (S29). In this case, a standby state in which steps S27 and S29 are repeatedly executed is entered. If the photographer's hand is released from the release button 21 in this state, the process skips step S29 with N and returns to step S11 again. On the other hand, when the release button 21 is fully pressed, the process proceeds to step S31 to stop the A mode display, that is, stop displaying the live view on the liquid crystal monitor 26, and turn off the power of the CCD 279 in the finder. (S33), the operation proceeds to the photographing operation A (M221). In the photographing operation A, the first reflecting mirror 201 is retracted from the photographing optical path, the diaphragm 103 is narrowed down to a set value, the shutter 213 is opened, and after the photographing operation by the main CCD 221 is performed, the first reflecting mirror 201 is set to the reflecting position. A known operation of returning the aperture 103 and the shutter 213 to the initial position is performed. When the photographing operation A ends, the process returns to step S1 and the above steps are repeated.

Returning to step S21, if 1R is off, it is determined in step S35 whether or not the AF instruction button 37 is on. If it is on, the process proceeds to step S37, and it is determined whether or not 1 is set in the B mode AF flag. When the AF instruction button 37 is operated during the B mode display, the autofocus operation in the A mode display is used. In this step, it is confirmed whether or not the AF instruction button 37 has been operated during the B mode display. If the flag is set as a result of the determination, the process proceeds to step S39, and ranging and focus adjustment operations are performed as in step S25. When the automatic focus adjustment ends, next, in step S41, the A mode display is fixed. This prevents the image from being disturbed and unsightly when returning from the A mode display to the B mode display again. By fixing the A mode display, the through image display on the liquid crystal monitor 26 is not updated until the B mode display is started thereafter. Next, the power source of the CCD 279 in the finder is turned off (S43), the B mode AF flag is reset (S44), and then the B mode display is started.

Returning to step S35, if the AF instruction button 37 is off, or if the B mode AF flag is not set to 1 in step S37, the process proceeds to step S45, and whether or not the display switching button 35 has been pressed. That is, it is determined whether or not it is on. If it is on, the A mode display M200 is terminated and the process proceeds to the information display M100. Returning to step S45, if the result of determination is that the display switching button 35 has not been pressed, that is, if it has been turned off, processing proceeds to step S47, whether the menu button 28 has been pressed, that is, whether it has been turned on. If it is ON, the process proceeds to the menu display M230 described with reference to FIG. If the menu button 28 is off, the process proceeds to step S49, and it is determined whether or not the through image switching button 34 is on (S49). If it is off, no button has been operated, so the process returns to step S11 and the above-described flow is repeated. When the live view display button 34 is operated in the state of the A mode display M200, the mode is switched to the B mode display M300 as described above. Therefore, if it is determined to be on in S49, first, similarly to step S43, the A mode display is fixed and then the process proceeds to the B mode display (M300).

Next, the flow of the B mode display M300 will be described with reference to FIG. When the B mode display is entered, first, the main CCD 221 is selected (S61), and supply of power to the main CCD 221 is started (S63). Next, as in step S1, photometric / exposure amount calculation is performed (S65), the first reflecting mirror 201 is rotated about the axis 201a, and retracted from the photographing optical path (S67). Subsequently, the focal plane shutter 213 is opened (S69), and a subject image is formed on the main CCD 221. As in step S7, a subroutine for setting the through image display condition 1 is executed (S71), and the through image display in the B mode display is started (S73). When the A mode display M200 is switched to the B mode display M300, the display on the liquid crystal monitor 26 is fixed from the A mode display fixed in step S51 to the start of the B mode display in step S73. The display is switched to B mode display, that is, through image display based on the image signal output from the main CCD 221.

Next, in step S76, it is determined whether or not the AF instruction button 37 has been operated, that is, whether or not it is on. As a result of the determination, if it is ON, the process proceeds to a step for performing autofocus using the A mode display. First, in step S77, the B mode display is fixed. This is to prevent image distortion when the display mode is changed, as in the case of fixing the A mode display in step S41. Next, the shutter 213 is closed (S78), the first reflecting mirror 201 is lowered (S79), and the subject light flux is guided to the in-finder CCD 279 side. Subsequently, the power of the main CCD 221 is turned off (S80), and 1 is set in the B mode AF flag. As described above, the B mode AF flag is a flag for determining whether or not an AF instruction is given during the B mode display in step S37. When these series of steps are completed, the display shifts to the A mode display shown in FIG. 5, and the autofocus operation is executed in step S39 as described above.

Returning to step S76, if the AF instruction button 37 has not been operated, the process proceeds to step S82, where it is determined whether the release button 21 has been fully pressed, that is, 2R is on. Proceed to shooting operation B. First, the through image display displayed on the liquid crystal monitor 26 is stopped, that is, the B mode display is stopped (S83), and the focal plane shutter 213 and the first reflection mirror 201 are returned to the initial state as in steps S78 and S79 ( S85, S87). Thereafter, the process proceeds to the photographing operation B (M320). In the photographing operation B, the first reflecting mirror 201 is retracted from the photographing optical path, the diaphragm 103 is narrowed down to the set value, the shutter 213 is opened, and after the photographing operation by the main CCD 221 is performed, the first reflecting mirror 201 is moved to the reflecting position. A known operation of returning the aperture 103 and the shutter 213 to the initial position is performed. When the photographing operation B is completed, the process returns to step S61 and the above steps are repeated.

Returning to step S81, if 2R is off, it is determined in step S101 whether the display switching button 35 is on. If it is on, the process returns to the information display M100, but before that, a process for ending the B mode display is performed from S103 to S109. First, the B mode display is stopped (S103), the focal plane shutter 213 is closed, the first reflecting mirror 201 is returned from the retracted position to the position where the light beam is reflected to the finder optical system (S107), and the main CCD 221 is turned off. (S109). When these operations are completed, the process proceeds to the information display M100.

Returning to step S101, if the display switching button 35 is off, the process proceeds to step S111 to determine whether the menu button 28 is on. If the result of determination is that it is on, menu display M310 is displayed, but before that, processing for stopping the live view display in B mode display is performed in steps S113 to S119. Since this process is the same as steps S103 to S109 described above, a description thereof will be omitted.

Returning to step S111, if the result of determination is OFF, it is determined in step S121 whether or not the through image switching button 34 is ON. If the result of determination is that it is on, the B mode display M300 is switched to the A mode display M200, but before that, switching processing is performed in steps S123 to S129. First, in step S123, the B mode display is fixed. This is to prevent image distortion when switching the through image display mode, as in step S77. Subsequent steps S125 to S129 are the same as steps S105 to S109 described above, and a description thereof will be omitted.

Returning to step S121, if the result of determination is No, the through image switching button 34 has not been operated. In this case, the process proceeds to step S143. Here, similarly to step S15, after the through image condition setting 2 subroutine is executed, the process proceeds to step S76 described above, and the above steps are repeated.

In this embodiment, the subject image is frozen in order to prevent the subject image from being disturbed on the monitor when shifting to autofocus using the A mode display during the B mode display. That is, when shifting from the B mode display to the A mode display, the B mode display is frozen from step S77 to step S9, and when returning from the A mode display to the B mode display, from step S41 to step S73. Freezing with A mode display. In addition, the subject image is prevented from being disturbed even when switching between normal A mode display and B mode display. When switching from A mode display to B mode display, the A mode display freezes from step S51 to step S73. At the time of switching from the B mode display to the A mode display, the B mode display is frozen from step S123 to S9. In addition to the method of ending freeze according to a predetermined operation, various methods may be selected as appropriate, such as freezing for a predetermined time until the image is stabilized. In this embodiment, the display is frozen when switching between the A mode display and the B mode display. However, the present invention can be applied to only one of the display modes.

Next, “through image condition setting 1” and “through image condition setting 2” will be described with reference to FIG. As described above, this subroutine is for adjusting the image brightness when displaying the subject image on the liquid crystal monitor 26. First, when the through image condition setting 1 subroutine is entered, in step S201, the electronic shutter speed TV1 and sensitivity SV1 at the time of next imaging are determined based on the output BVs of the photometric sensor 281. Since the aperture value when displaying a through image is an open aperture value, if this aperture value is AVs,
AVs + TV1 = BVs + SV1
There is a relationship
BVs-AVs = TV1-SV1
It becomes. Since the left side of this equation is a known value, TV1 and SV1 may be obtained from the value on the left side according to a program line or a table as appropriate. Thereafter, the determined electronic shutter speed TV1 and sensitivity SV1 are stored and set in the respective registers (S207). The CCD drive circuit 223 or the CCD drive circuit 283 performs drive control of the CCD 221 or 279 based on the TV1 and SV1 set and stored here, and reads out the photoelectric conversion signal. When the setting of TV1 and SV1 is completed in step S207, the process returns to the original flow.

Next, “through image condition setting 2” will be described. When the setting 2 subroutine is entered, first, a difference ΔEV between the target image brightness (predetermined value) and the image brightness at the time of previous imaging is calculated (S203). Subsequently, the electronic shutter speed TV1 and sensitivity SV1 at the next imaging are determined so that the image brightness is constant (S205). This decision is based on the following factors:
・ Aperture value AVs
-Electronic shutter speed TV0 at the time of previous imaging
・ Sensitivity SV0 at the time of previous imaging
The difference ΔEV between the target image brightness and the previous image brightness
First, as a basic expression of the exposure condition, AVs + TV0 = BV0 + SV0
It is.

Here, BV0 is the previous luminance, but the true value is not known and is a provisional value in the above basic formula. Since the true luminance value BV0 is different from the target, ie, ΔEV,
BV0 = AVs + TV0−SV0 + ΔEV
= AV1 + TV1-SV1
Thus, TV1 and SV1 are obtained from this relational expression. Here, the difference ΔEV may be obtained from, for example, the difference between the weighted average of the output of each pixel of the image sensor and the target value. When step S205 ends, the process proceeds to step S207 described above and returns to the original flow.

As described above, in this embodiment, when the AF instruction button 37 is operated during the B mode display (S76), after preparing for shifting to the A mode display in steps S77 to S81, the A mode display is performed. , And each step is executed sequentially from step S1, branching to step S39 in steps S35 and S37, distance measurement and focus adjustment are performed, and then the display returns to the B mode again. As described above, even in the B mode display, the photographer can easily perform the autofocus operation as necessary, which is very convenient for a subject that is difficult to focus with manual focus.

In this embodiment, the autofocus operation can be performed during the A mode display, while the autofocus operation cannot be performed during the B mode display. However, on the contrary, for example, when the TTL phase difference method autofocus device arranged in the viewfinder is eliminated and instead the focus method is performed by the contrast method based on the output from the main CCD 221. , Auto focus is possible even in B mode display. In such a case, when the release button 21 is operated during the A mode display, the mode may be shifted to the B mode to perform autofocus.

The digital single-lens reflex camera of the present embodiment includes a photographic lens 101, an up position retracted out of the optical path of the photographic lens 101, and a first reflecting mirror that can move to a down position that guides a subject light beam to the optical viewfinder in the optical path. 201, and when the first reflecting mirror 201 is in the down position, the focus state of the photographing lens 101 is detected by the distance measuring circuit 217 on the basis of the subject light flux transmitted through the first reflecting mirror 201 and the auto focus operation is performed. A B mode in which the subject image captured by the main CCD 221 for image recording is continuously displayed on the liquid crystal monitor 26 with the autofocus means to be executed and the first reflecting mirror 201 moved to the up position (retracted position). In the viewfinder, the live view display means for display and the first reflection mirror 201 are moved to the down position (reflection position). A through image display means in the A mode for continuously displaying the subject image picked up by the arranged CCD 279 in the finder on the liquid crystal monitor 26, and an AF different from the release button during the through image display operation in the B mode display. When the instruction button 37 is operated, the first reflection mirror 201 is moved to the down position (reflection position), and then the through image display operation in the A mode display and the autofocus operation by the autofocus means are executed. As a result, it is possible to provide a digital single-lens reflex camera capable of accurate focusing even when a through image is displayed in B mode display.

In the present embodiment, the photographing lens 101, the focusing state of the photographing lens 101 is detected by the distance measuring circuit 217, and the image is picked up by the main CCD 221 for image recording. When a live view display means in B mode display for continuously displaying the subject image on the liquid crystal monitor 26 is provided, and an AF instruction button 37 different from the release button is operated during the live view display operation in the B mode display. Since the autofocus operation by the autofocus means is executed, it is possible to provide a digital single-lens reflex camera capable of accurate focusing even when a through image is being displayed in B mode display. In this embodiment, the instruction of the AF operation during the B mode display is instructed by the operation of the AF instruction button 37. However, the present invention is not limited to this, and another operation member may be used and also used as another operation member. You may do it. In any case, any operation member different from the release button may be used.

Note that the present invention is not limited to a single-lens reflex camera, and can selectively display both an image sensor for observing a subject and an image sensor for recording image information data, and can display image information from the image sensor for observing the subject. Of course, the present invention can be applied to any electronic camera that can execute the autofocus function. The present invention can also be applied to an electronic camera that selectively displays through images of two or more image pickup devices and only performs through image display of a specific image pickup device.

1 is an external perspective view of a digital single lens reflex camera according to an embodiment of the present invention. 1 is a block diagram showing a schematic optical configuration of a digital single-lens reflex camera according to an embodiment of the present invention. 1 is a block diagram illustrating an overall configuration of a digital single-lens reflex camera according to an embodiment of the present invention. It is a block diagram which shows the display mode of the digital single-lens reflex camera in one Embodiment of this invention, and the hierarchical structure of the operation mode menu. It is a flowchart of A mode display in one embodiment of the present invention. It is a flowchart of the B mode display in one Embodiment of this invention. 6 is a flowchart of through image condition setting 1 and through image condition setting 2 in an embodiment of the present invention. In one Embodiment of this invention, the display on a liquid crystal monitor is shown, (A) is a through image display in A mode display, (B) is a figure which shows the through image display in B mode display.

Explanation of symbols

10 Lens barrel 20 Camera body 21 Release button 22 Mode dial 23 Power switch 24 Control switch 26 Liquid crystal monitor 27 Playback button 28 Menu button 30 Cross key 31 OK button 33 Viewfinder 34 Through image switching button 35 Display switching button 36 Preview button 37 AF Instruction button 201 First reflection mirror 205 Screen mat 213 Focal plane shutter 221 Main CCD
229 Body CPU
279 CCD in the viewfinder
227 Image processing circuit 285 CCD switching circuit

Claims (4)

A taking lens,
Mirror means movable to a first position retracted out of the optical path of the photographic lens and a second position for guiding the subject light beam to the optical viewfinder in the optical path;
Auto-focus means for detecting the focus state of the photographing lens and performing auto-focus operation based on the subject luminous flux transmitted through the mirror means when the mirror means is in the second position;
First through-image display means for continuously displaying on the display device a subject image picked up by an image-recording image sensor with the mirror means moved to the first position;
Second through-image display means for continuously displaying a subject image picked up by an image pickup device arranged in the viewfinder on a display device in a state where the mirror means is moved to the second position;
When a predetermined operation member different from the release button is operated during the live view display operation by the first live view display means, the mirror means is moved to the second position, and then the second position is displayed. A control means for performing a live view display operation by the live view display means and an autofocus operation by the autofocus means,
A digital single-lens reflex camera characterized by comprising: A taking lens,
Mirror means movable to a first position retracted out of the optical path of the photographic lens and a second position for guiding the subject light beam to the optical viewfinder in the optical path;
Auto focus means for detecting the focus state of the photographing lens based on the subject luminous flux incident through the mirror means and performing an auto focus operation;
First through-image display means for continuously displaying on the display device a subject image picked up by an image-recording image sensor with the mirror means moved to the first position;
When a predetermined pointing member different from the release button is operated during the live view display operation by the first live view display means, the mirror means is moved to the first position, and then the autofocus is performed. Control means for executing an autofocus operation by the means;
A digital single-lens reflex camera characterized by comprising: A taking lens,
Auto focus means for detecting the focus state of the taking lens and executing auto focus operation;
First through-image display means for continuously displaying a subject image captured by an image-recording image sensor on a display device;
Control means for executing an autofocus operation by the autofocus means when a predetermined indicating member different from the release button is operated during the live view display operation by the first live view display means;
A digital single-lens reflex camera characterized by comprising: A taking lens,
A through image display means for selectively switching the outputs of the first and second image sensors and displaying an image repeatedly acquired by the image sensor as a moving image on the display device;
An operation member for instructing a recording preparation operation of the subject image based on an output of the first image sensor;
Auto focus means for detecting a focus state of the photographing lens and performing auto focus operation during display operation by the through image display means based on the output of the first or second image sensor;
Control of switching to another through image display unit that activates the auto focus unit when a predetermined pointing member different from the release button is operated during the through image display in which the auto focus unit is inactive. Means,
An electronic camera comprising: