JP2009048122A - Photographing equipment and method of controlling same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide photographing equipment capable of highly accurately performing focus adjustment by decreasing time lag when photographing is performed from a live view display state, and to provide a method of controlling the photographing equipment. <P>SOLUTION: The photographing equipment displays enlarged object images on a liquid crystal monitor 26 when operating an enlarged button 34 in live view display (#55); performs automatic focus adjustment with a contrast AF (#105) when half-pushing of a release button 21 is performed in the state (#53); further, performs highly accurate automatic focus adjustment (#121) is performed with a phase difference AF when fully pushing of the release button 21 (#107); then, performs focus detection for focus detection points in a range enlarged and displayed (#182); and drives a photographing optical system 101 at a focusing position based on the focus detection result (#185-#195). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a digital camera having a live view display function, and more specifically, has a so-called live view display function (also referred to as a through image display function or an electronic viewfinder function) for displaying an image acquired by an image sensor on a display device, The present invention relates to a photographing apparatus capable of adjusting the focus of a photographing lens by using an image signal during live view display, and a method for controlling the photographing apparatus.

In a conventional digital camera, an object image is observed using an optical viewfinder. Recently, however, digital cameras with a live view display function have been put on the market, which eliminate the optical finder or display an image acquired by the image sensor together with the optical finder on a display device such as a liquid crystal monitor for observing the subject image. Yes.

Such a digital camera with a live view display function is convenient and easy to observe because a subject image acquired by an image sensor is displayed as it is. However, in a digital single-lens reflex camera, in order to perform live view display, the movable mirror disposed in the photographing optical path is temporarily retracted from the optical path, so that the sub mirror attached to the movable mirror is displayed during live view display. Thus, the AF (Auto focus) mechanism based on the conventional phase difference method in which the amount of focus deviation of the photographing lens is detected using the subject light beam reflected by the lens cannot be used.

For example, Patent Document 1 discloses a digital single-lens reflex camera that uses contrast AF for detecting contrast information based on an image signal from an image sensor and performing AF, and phase difference AF. This digital single-lens reflex camera focuses the photographing lens only by contrast AF when performing live view display.
JP 2001-281530 A

As described above, in a digital single-lens reflex camera that performs live view display, if focus adjustment is performed with normal contrast AF, there are the following problems. That is, contrast AF is also called a hill-climbing method, and it is necessary to move the photographic lens back and forth in search of a point where the contrast value of the image output is maximum, so that it takes time to focus. In addition, in an interchangeable lens single-lens reflex camera, it is necessary to communicate the contrast information of the image signal to the photographing lens side for each frame. Therefore, if an attempt is made to increase the focus accuracy, the number of communications increases, and further focusing is achieved. It takes time to complete. In addition, some photographing lenses, such as a macro lens, have a large extension amount from the infinite end, and in this case, the focusing time becomes long.

The present invention has been made in view of such circumstances, and when photographing from a live view display state, a photographing apparatus and a photographing apparatus control method capable of performing focus adjustment with little time lag and high accuracy. The purpose is to provide.

In order to achieve the above object, a photographing apparatus according to a first aspect of the present invention receives a subject luminous flux incident through a photographing lens on an imaging surface, and photoelectrically converts the subject image formed on the imaging surface to obtain subject image data. Imaging means for outputting, display means for performing a live view display operation using subject image data acquired by the imaging means, and contrast information of the subject image from the subject image data while performing the live view display operation. And a contrast AF means for guiding the photographing lens within a predetermined focusing tolerance based on the contrast information, and a sensor for detecting a focal shift amount of the photographing lens at a plurality of points in the photographing screen by a phase difference method. And including the photographing lens according to any of a plurality of pieces of defocus amount information detected by the sensor. A phase difference AF unit that leads to a narrower focus tolerance range, and when the release button is pressed halfway during the live view display operation, the focus adjustment operation by the contrast AF unit is performed. After that, when the release button is fully pressed, the control means for controlling the focus adjustment operation by the phase difference AF means is provided, and the display means is a part of the photographing screen. When the enlarged live view display is performed, the phase difference AF means detects the focus shift amount at a focus detection point included in the enlarged area.

In order to achieve the above object, a method for controlling a photographing apparatus according to a second aspect of the present invention provides a half-press operation of a release button during continuous live view display in which a part of the subject image data is cut out and live view display is performed. When the focus is adjusted, the focus of the photographic lens is adjusted based on the contrast information of the clipped subject image data. After that, when the release button is fully pressed, the phase difference method is applied to the focus detection points existing within the clipped range. Is used to detect the amount of defocus of the photographing lens, and the focus adjustment operation of the photographing lens is performed based on the detection result.

In order to achieve the above object, a photographing apparatus according to a third aspect of the present invention receives a subject luminous flux incident through a photographing lens on an imaging surface and photoelectrically converts the subject image formed on the imaging surface to obtain subject image data. Imaging means for outputting; display means for performing live view display operation using subject image data acquired by the imaging means; and a portion of the subject image data cut out in response to an operation of an enlargement operation member. An enlarged display means for performing enlarged display, and a sensor for detecting a focal shift amount of the photographing lens at a plurality of points in the photographing screen by a phase difference method, and based on a plurality of focal shift amount information detected by the sensor Phase difference AF means for guiding the photographic lens to within a focus allowable range, and when the release button is operated, the enlarged display means performs the enlarged display. For focus detecting points existing in a range to detect the defocus amount by the phase difference AF unit performs the focusing operation of the photographing lens based on the detection result.

According to a fourth aspect of the present invention, there is provided a photographing apparatus according to the third aspect, wherein contrast information of the subject image is obtained from subject image data acquired by the imaging means, and the photographing lens is attached to the first joint based on the contrast information. A first contrast AF means for guiding the focus within the permissible focus range, and adjusting the focus of the photographing lens within the first permissible focus range by the first contrast AF means in response to a half-pressing operation of the release button; When the release button is fully pressed in this state, a focus adjustment operation is executed by the phase difference AF means.
According to a fifth aspect of the present invention, there is provided a photographing apparatus according to the fourth aspect, wherein the photographing lens is guided to a second focusing allowable range narrower than the first focusing allowable range based on the contrast information. A second contrast AF means, and after the focus adjustment operation of the photographing lens is performed within the first focus allowable range in response to a half-press operation of the release button, the second focus permission is further provided. When the release button is fully pressed with the focus adjustment operation of the photographing lens within the range, the focus adjustment operation by the phase difference AF means is prohibited.

ADVANTAGE OF THE INVENTION According to this invention, when image | photographing from a live view display state, there is little time lag and the imaging device which can perform focus adjustment with high precision and the control method of an imaging device can be provided.

Hereinafter, a preferred embodiment using a digital single lens reflex 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 single-lens reflex camera according to an embodiment of the present invention as seen from the back.

On the upper surface of the camera body 200, a release button 21, a shooting mode dial 22, an information setting dial 24, a strobe 200, 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 the image sensor 221 (see FIG. 2).

The shooting mode dial 22 is an operation member configured to be rotatable, and by matching a picture display or a symbol representing the shooting mode provided on the shooting mode dial 22 with an index, a full auto shooting mode (AUTO), a program Shooting mode (P), aperture priority shooting mode (A), shutter shooting priority 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 information setting dial 24 is an operation member configured to be rotatable, and a desired setting value, mode, or the like can be selected by rotating the information setting dial 24 on an information display screen or the like. The strobe 50 is a pop-up type auxiliary illumination device. By operating an operation button (not shown), the strobe 200 pops up and can irradiate the subject.

On the back of the camera body 200, there are a liquid crystal monitor 26, a continuous / single shooting button 27, an AF lock button 28, an up cross button 30U, a down cross button 30D, a right cross button 30R, and a left cross button 30L (these buttons). The cross buttons 30U, 30D, 30R, and 30L are collectively referred to as cross buttons 30), an OK button 31, a live view display button 33, an enlarge button 34, a menu button 37, and a playback button 38. . The liquid crystal monitor 26 is a display device that performs live view display, reproduces and displays a captured subject image, and displays shooting information and menus. Any liquid crystal display can be used as long as it can perform these displays.

The continuous shooting / single shooting button 27 is a continuous shooting mode in which continuous shooting is performed while the release button 21 is fully pressed, and a single shooting mode in which one frame is shot when the release button 21 is fully pressed. This is an operation member for switching. The AF lock button 28 is an operation member for fixing the focus of the subject. Thus, even if the composition AF is changed after the focusing AF lock button 28 is operated on the subject to be photographed to fix the focus, it is possible to perform photographing that is in focus on the photographing subject.

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 liquid crystal monitor 26. In addition, when the subject image recorded on the recording medium is reproduced and displayed, Also used for image selection instructions. In addition to providing four buttons for up, down, left, and right, it is possible to replace with an operation member that can be operated in two dimensions, such as a switch that can detect the operation direction in two dimensions, such as a touch switch. It is. 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 live view display button 33 is an operation button for switching from a display screen for information display or the like to a live view display, or from a live view display to a display screen for information display or the like. The live view display is a mode in which the subject image is displayed on the liquid crystal monitor 26 for observation based on the output of the image sensor 221 for recording the subject image, and the information display is for setting the shooting information of the digital camera. This mode is displayed on the liquid crystal monitor 26. The enlargement button 34 is an operation member for enlarging and displaying a part of the subject image on the liquid crystal monitor 26, and the enlargement position can be changed by operating the cross button 30 described above.

The menu button 37 is an operation member 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 37, a menu screen is displayed on the 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 playback button 38 is an operation button for instructing the liquid crystal monitor 26 to display a subject image recorded after shooting. The subject image data stored in the later-described SDRAM 267 and recording medium 277 in a compression mode such as JPEG is expanded and displayed.

A recording medium storage lid 40 is attached to the side surface of the camera body 200 so as to be freely opened and closed. When the recording medium storage lid 40 is opened, a loading slot for the recording medium 277 is provided therein, and the recording medium 277 can be detachably loaded into the camera body 200.

Next, the overall configuration of the digital single-lens reflex camera mainly including the electric system will be described with reference to FIG. The digital single-lens reflex camera according to this embodiment includes an interchangeable lens 100 and a camera body 200. In the present embodiment, the interchangeable lens 100 and the camera body 200 are configured separately and are electrically connected by the communication contact 300, but the interchangeable lens 100 and the camera body 200 can also be configured integrally. . The circuit block of the built-in strobe 50 is omitted in FIG.

Inside the interchangeable lens 100, a photographing optical system 101 for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture amount are arranged. The photographing optical system 101 is driven by a lens driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109. The focal length and focal position of the photographing optical system 101 driven by the lens driving mechanism 107 are detected by the optical system position detection mechanism 105.

The lens driving mechanism 107, the aperture driving mechanism 109, and the optical system position detection mechanism 105 are each connected to a lens CPU 111, and the lens CPU 111 is connected to the camera body 200 via a communication contact 300. The lens CPU 111 controls the inside of the interchangeable lens 100. The lens CPU 111 controls the lens driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to perform aperture value control. In addition, the lens CPU 111 transmits the focal length and focal position information detected by the optical system position detection mechanism 105 to the camera body 200.

In the camera body 200, a position tilted by 45 degrees with respect to the optical axis of the lens (the lowered position, the subject image observation position) in order to reflect the subject image to the observation optical system, and a subject image to be guided to the image sensor 221. A movable mirror 201 that can be rotated between the jumped up position (the raised position and the retracted position) is provided. Above the movable mirror 201, a focusing screen 205 for forming a subject image is disposed, and above this focusing screen 205, a pentaprism 207 for horizontally reversing the subject image is disposed.

An eyepiece lens (not shown) for observing the subject image is arranged on the emission side (right side in FIG. 2) of the pentaprism 207, and the photometric sensor 211 is arranged on the side of the pentaprism 207 so as not to interfere with the observation of the subject image. Has been. The photometric sensor 211 is connected to a photometric processing circuit 241, and the output of the photometric sensor 211 is subjected to processing such as amplification and analog-digital conversion by the photometric processing circuit 241.

Near the center of the movable mirror 201 described above is a half mirror, and on the back surface of the movable mirror 201, a sub mirror 203 for reflecting subject light transmitted through the half mirror portion to the lower part of the camera body 200 is provided. ing. The sub mirror 203 is rotatable with respect to the movable mirror 201. When the movable mirror 201 is flipped up (the position indicated by a broken line in FIG. 2), the sub mirror 203 is rotated to a position that covers the half mirror portion. When in the observation position (lowering position), it is in an open position with respect to the movable mirror 201 as shown.

This movable mirror 201 is driven by a movable mirror drive mechanism 239. Further, a phase difference AF sensor 243 is disposed below the sub mirror 203, and an output of the phase difference AF sensor 243 is connected to a phase difference AF processing circuit 245. The phase difference AF sensor 243 is a known phase difference that separates the light flux around the photographing optical system 101 into two light fluxes in order to measure the amount of focus shift (defocus amount) of the subject image formed by the photographing optical system 101. It consists of an AF optical system and a pair of sensors. Further, the phase difference AF sensor 243 can detect the focus at each of a plurality of points in the shooting screen.

A focal plane type shutter 213 for controlling the exposure time is disposed behind the movable mirror 201, and this shutter 213 is driven and controlled by a shutter drive mechanism 237. An imaging element 221 is disposed behind the shutter 213 and photoelectrically converts a subject image formed by the photographing optical system 101 into an electrical signal. The imaging element 211 may be a CCD (Charge Coupled Devices) or a CMOS (Complementary).
Needless to say, a two-dimensional image sensor such as Metal Oxide Semiconductor can be used.

The image sensor 221 is connected to the image sensor drive circuit 223, and the image sensor drive circuit 223 reads an image signal from the image sensor 221. The image sensor driving circuit 223 is connected to a preprocessing circuit 225. The preprocessing circuit 225 performs preprocessing for image processing such as pixel thinning processing for live view display and clipping processing for enlarged display. Do.

A dustproof filter 215, a piezoelectric element 216, and an infrared cut filter / low pass filter 217 are disposed between the shutter 213 and the image sensor 221. A piezoelectric element 216 is fixed around the dust filter 215, and this piezoelectric element 216 is vibrated by ultrasonic waves by a dust filter driving circuit 235. The dust attached to the dustproof filter 215 is removed by the vibration wave generated in the piezoelectric element 216.

The infrared cut filter / low pass filter 217 is an optical filter for removing the infrared light component and the high frequency component from the subject light flux. The dust filter 215, the piezoelectric element 216, the infrared cut filter / low pass filter 217, and the image sensor 221 are integrally formed in an airtight manner so that dust and the like do not enter. The integrated image sensor 223 and the like can be moved by the shift mechanism 233 along the X-axis direction and the Y-axis direction on the imaging surface of the image sensor 223, respectively.

The camera shake sensor 227 is a sensor that detects vibration caused by camera shake or the like applied to the camera body 200, and this output is connected to the camera shake correction circuit 229. The camera shake correction circuit 229 generates a camera shake correction signal for removing vibrations such as camera shake, and the output of the camera shake correction circuit 229 is connected to the shift mechanism drive circuit 231. The shift mechanism drive circuit 231 inputs a camera shake correction signal, and drives the shift mechanism 233 based on this signal. By this shift mechanism 233, the image pickup device 221 and the like are moved so as to cancel vibrations such as camera shake applied to the camera body 200, thereby performing vibration isolation.

The pre-processing circuit 225 is an ASIC (Application Specific
Integrated Circuit Application Specific Integrated Circuit) 250 is connected to a data bus 252 in the circuit. The data bus 252 includes a sequence controller (hereinafter referred to as “body CPU”) 251, an image processing circuit 257, a compression / decompression circuit 259, a video signal output circuit 261, an SDRAM control circuit 265, an input / output circuit 271, and a communication circuit 273. A recording medium control circuit 275, a flash memory control circuit 279, and a switch detection circuit 283 are connected.

The body CPU 251 connected to the data bus 252 controls the operation of this digital single lens reflex camera. A contrast AF circuit 253 and an AE circuit 255 are connected in parallel between the preprocessing circuit 225 and the body CPU 251 described above. The contrast AF circuit 253 extracts a high frequency component based on the image signal output from the preprocessing circuit 225, and outputs contrast information based on the high frequency component to the body CPU 251. The AE circuit 255 outputs photometric information corresponding to the subject brightness to the body CPU 251 based on the image signal output from the preprocessing circuit 225.

The image processing circuit 257 connected to the data bus 252 is a variety of images such as digital amplification (digital gain adjustment processing) of digital image data, color correction, gamma (γ) correction, contrast correction, and live view display image generation. Perform processing. The compression / decompression circuit 259 is a circuit for compressing the image data stored in the SDRAM 267 by a compression method such as 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 261 is connected to the liquid crystal monitor 26 via the liquid crystal monitor drive circuit 263. The video signal output circuit 261 is a circuit for converting the image data stored in the SDRAM 267 and the recording medium 277 into a video signal for display on the liquid crystal monitor 26. As shown in FIG. 1, the liquid crystal monitor 26 is disposed on the back surface of the camera body 200. However, the liquid crystal monitor 26 is not limited to the back surface as long as the photographer can observe the image. .

The SDRAM 267 is connected to the data bus 261 via the SDRAM control circuit 265, and the SDRAM 267 temporarily stores the image data processed by the image processing circuit 257 or the image data compressed by the compression / decompression circuit 259. This is a buffer memory.

The above-described image sensor driving circuit 223, preprocessing circuit 225, camera shake correction circuit 229, shift mechanism driving circuit 231, dustproof filter driving circuit 235, shutter driving mechanism 237, movable mirror driving mechanism 239, photometry processing circuit 241, phase difference AF processing An input / output circuit 271 connected to the circuit 245 controls data input / output with each circuit such as the body CPU 251 via the data bus 252.

The communication circuit 273 connected to the lens CPU 111 via the communication contact 300 is connected to the data bus 252 and exchanges data and communicates control commands with the body CPU 251 and the like. A recording medium control circuit 275 connected to the data bus 252 is connected to the recording medium 277 and controls recording of image data and the like on the recording medium 277 and reading of the image data and the like.

The recording medium 277 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 200. In addition, the hard disk may be configured to be connectable via a communication contact.

The flash memory control circuit 279 is connected to a flash memory 281, and the flash memory 235 stores a program for controlling the operation of the digital single-lens reflex camera, and the body CPU 251 stores the program in the flash memory 281. The digital single lens reflex camera is controlled according to the stored program. Note that the flash memory 281 is an electrically rewritable nonvolatile memory.

Various switches including a 1R switch for detecting the first stroke (half press) of the shutter release button 21, a 2R switch for detecting the second stroke (full press), and a live view display switch that is turned on by operating the live view display button 33 285 is connected to the data bus 252 via the switch detection circuit 283. The various switches 285 include an enlargement switch linked to the enlargement button 34, a power switch, a menu switch linked to the menu button 37, an AF lock switch linked to the AF lock button 28, and a continuous / single shot button 27. It includes a continuous / single-shot switch and other various switches linked to other operation members.

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowcharts shown in FIGS. FIG. 3 shows a power-on reset operation by the body CPU 251 on the camera body 200 side. When a battery is loaded in the camera body 200, this flow starts, and it is first determined whether the power switch of the camera body 200 is on (# 1). If the result of the determination is that the power switch is off, it enters a sleep state that is a state of low power consumption (# 3). In this sleep state, interrupt processing is performed only when the power switch is turned on, and processing for turning on the power switch is performed in step # 5 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 # 1, if the power switch is on, or if the sleep state is canceled in step # 3, power supply is started (# 5). Next, a dust removing operation is performed in the dust filter 215 (# 7). In this operation, a driving voltage is applied from the dust filter driving circuit 235 to the piezoelectric element 216 fixed to the dust filter 215, and dust and the like are removed by ultrasonic vibration waves.

Next, if there is information such as the photographing mode set by the photographing mode dial 22 or the like, ISO sensitivity, manually set shutter speed or aperture value, those photographing conditions and lens information are read (# 9). . The lens information is read from the lens CPU 111 through the communication circuit 273 to read lens characteristic information such as the open aperture, focal length information, and lens identification number of the interchangeable lens 100.

Subsequently, photometry / exposure amount calculation is performed (# 11). In this step, the subject brightness is measured by the photometric sensor 211, an exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated according to the shooting mode and shooting conditions using the exposure amount. Thereafter, the photographing information is displayed on the liquid crystal monitor 26 (# 13). The shooting information includes the shooting mode and shooting conditions read in step # 9, and the shutter speed and aperture value exposure control values calculated in step # 11.

Next, it is determined whether or not the live view display switch is on (# 15). As described above, when the photographer observes the subject image in the live view display, the live view display button 33 is operated. If the result of determination is that the live view display switch is on, a live view display operation subroutine is executed (# 31). This live view display operation will be described later with reference to FIGS.

If the result of determination in step # 15 is that the live view display switch is not on, it is determined whether or not the playback switch is on (# 17). The playback mode is a mode in which the still image data recorded on the recording medium 277 is read and displayed on the liquid crystal monitor 26 when the playback button 38 is operated. If the result of determination is that the regeneration switch is on, regeneration operation is executed (# 33).

If the result of determination in step # 17 is that the playback switch is not on, it is determined whether or not the menu switch is on (# 19). In this step, it is determined whether the menu button 37 is operated and the menu mode is set. If the result of determination is that the menu switch is on, a menu is displayed on the liquid crystal monitor 26 and menu setting operation is performed (# 35). Various setting operations such as AF mode, white balance, ISO sensitivity setting, and drive mode setting can be performed by the menu setting operation.

If the result of determination in step # 19 is that the menu switch is not on, it is determined whether or not the release button 21 has been pressed halfway, that is, whether or not the 1R switch is on (# 21). If the result of determination is that the 1R switch is on, a subroutine for shooting operation A for shooting preparation and shooting is executed (# 37). Details of this subroutine will be described later with reference to FIG.

If the result of determination in step # 21 is that the 1R switch is not on, it is determined whether or not the power switch is on as in step # 1 (# 23). If the result of determination is that the power switch is on, processing returns to step # 9 and the above operation is repeated. On the other hand, if the power switch is not on, the power supply is stopped (# 25), the process returns to step # 3, and the above-described sleep state is entered.

Next, the live view display operation in step # 31 will be described with reference to FIGS. When this subroutine is entered, first, the photographing information display is turned off (# 41). In step # 13, the shooting information is displayed on the liquid crystal monitor 26. In this step, the display of the shooting information is stopped in order to display the live view on the liquid crystal monitor 26. Subsequently, in the same manner as in step # 11, photometry / exposure amount calculation is performed (# 43).

Next, the movable mirror 201 is retracted from the optical axis of the photographing optical system 101 (# 45), and the shutter 213 is opened (# 47). By these operations, a subject image by the photographing optical system 101 is formed on the image sensor 221. Subsequently, live view condition initial setting is performed (# 49). In this step, in order to set the electronic shutter speed and sensitivity conditions for driving the image sensor 221, the brightness (appropriate brightness) for the liquid crystal monitor 26 is obtained using the photometry / exposure amount calculation result obtained in step # 43. Calculation and setting for displaying an image of brightness.

Next, the start of live view display is instructed (# 51). That is, the image sensor 221 and the image processing circuit 257 are instructed to display the image data acquired by the image sensor 221 on the liquid crystal monitor 26 as a moving image. The photographer can determine the shooting composition based on the live view display. Note that the electronic shutter speed, ISO sensitivity, and the like are controlled so that the screen brightness of the liquid crystal monitor 26 is constant during live view display.

When live view display is started, it is next determined whether or not the release button 21 has been half-pressed, that is, whether or not the 1R switch is on (# 53). If the result of determination is that the 1R switch has not been turned on, it is determined whether or not the enlargement button 34 has been operated, that is, whether or not the enlargement switch has been turned on (# 55). As a result of the determination, if the enlargement switch is not on, the process jumps to step # 71 (FIG. 5). On the other hand, if the enlargement switch is on, it is determined whether or not the enlargement display is being performed ( # 57).

As described above, the enlargement button 34 is an operation button for enlarging and displaying a subject image in the live view display mode. When the enlargement button 34 is operated once, the enlargement display mode is set. The enlarged display mode is canceled. Therefore, in step # 57, it is determined whether to continue or end the enlarged display mode.

If the result of determination in step # 57 is that enlarged display is not in progress, that is, if the display is in the enlarged display mode from the non-enlarged display (normal live view display), the cutout range is instructed (# 59), The start of enlarged display is instructed (# 61). The enlarged display is performed by instructing the preprocessing circuit 225 and cutting out image data corresponding to the enlarged range from the image data read from the image sensor 221.

If the result of determination in step # 57 is that enlarged display is in progress, the enlarged display mode is terminated and processing for returning to normal live view display is performed. That is, a full screen output instruction is given to the preprocessing circuit 225 (# 63), and an enlargement display stop instruction is given to the image processing circuit 257 (# 65). When the process of step # 61 or # 65 is completed, the process proceeds to step # 71, and it is determined whether or not the cross button 30 has been operated.

If the result of determination in step # 71 is that the cross button 30 has been operated, it is next determined whether or not enlarged display is in progress (# 73). As a result of the determination in Step # 71 or Step # 73, if either is N, the process jumps to Step # 77. If the determination in both steps is Y, that is, in enlarged display. If the cross switch is operated, the movement of the enlargement area corresponding to the cross button 30 is instructed (# 75).

As described above, in this embodiment, when the live view display mode is entered, the subject image is displayed on the full screen on the liquid crystal monitor 26 as shown in FIG. 13A (# 51). When the enlarge button 34 is operated in this state (# 55), the subject image is enlarged and displayed as shown in FIG. 13B (# 61). This enlarged display is a part of the full screen display as shown in FIG. Thereafter, when the cross button 30 is operated (# 71), an enlarged display is performed at a position corresponding to the operation of the cross button 30 (# 75). The enlarged display at this time corresponds to a position corresponding to the operation of the cross button 30 in a part of the full screen display as shown in FIG.

Next, it is determined whether or not the live view display switch linked to the live view display button 33 is ON (# 77). Once the live view display button 33 is operated, the live view display mode is set. When the live view display button 33 is operated again, the live view display mode is canceled. If the result of determination in step # 77 is on, the live view display mode is terminated in step # 85 and thereafter.

If the result of determination in step # 77 is that the live view display switch is not on, it is determined whether or not the playback switch linked to the playback button 38 is on (# 79). In the reproduction mode, it is necessary to end the live view display mode in order to reproduce and display the image data recorded on the recording medium 277 on the liquid crystal monitor 26. If the result of determination in step # 79 is on, the live view display mode is terminated in step # 85 and thereafter.

If the result of determination in step # 79 is that the playback switch is not on, it is determined whether or not the menu switch linked to the menu button 37 is on (# 81). In the menu setting mode, in order to display the menu on the liquid crystal monitor 26, it is necessary to end the live view display mode. If the result of determination in step # 81 is on, the live view display mode is terminated in step # 85 and thereafter.

If the result of determination in step # 81 is that the menu switch is not on, it is determined whether or not the power switch is on (# 83). If the result of determination is that the power switch is off, in order to perform power off processing, live view display is first terminated in step # 85 and thereafter. If the result of determination in step # 83 is on, processing returns to step # 53 and the above operation is repeated.

When the process proceeds to step # 85 to end the live view display, the focus display is first turned off (# 85). As will be described later, when the subject is in focus, the first in-focus display 311 and the second in-focus display 312 are displayed as shown in FIGS. If so, turn it off. Subsequently, a live view display stop instruction is given to the pre-processing circuit 225, the image processing circuit 257, etc. (# 87). After that, the shutter 213 is instructed to close the shutter (# 89), the movable mirror 201 is returned (moved to the lowered position) (# 91), and the process returns to the original routine.

If the result of determination in step # 53 (FIG. 4) is that the 1R switch is on, AE information is read (# 101, FIG. 6). In step # 43, since the movable mirror 201 was in the lowered position, the photometric sensor 211 was able to perform photometry. However, in this step, the movable mirror 201 is in the retracted position (upward position). Photometry with 211 is not possible. Therefore, AE information is acquired based on the output of the AE circuit 255. Subsequently, it is determined whether or not the second focus display is being performed (# 102). As will be described later, when the photographing optical system 101 is brought into the second in-focus state by the high-precision contrast AF, the second in-focus display is performed (# 277 in FIG. 11). After reaching the second in-focus state, in step # 105, when the photographing optical system 101 is driven again by contrast AF, the operational feeling is not good. Step # 105 is skipped.

If the result of determination in step # 102 is that the second in-focus display is not in progress, it is determined whether or not the mode is the phase difference AF only mode (# 103). The AF mode can be selected on the AF mode selection screen (see FIG. 14) in the menu setting operation in step # 35. That is, in this embodiment, the i-AF mode that performs only contrast AF based on the output of the image sensor 221, the PD-AF mode that performs only phase difference AF based on the output of the phase difference AF sensor 243, and the contrast AF and level. Either i-AF + PD-AF mode in which both phase difference AF is performed can be selected.

If the result of determination in step # 103 is the phase difference AF only mode, or the result of determination in step # 102 is that the second in-focus display is in progress, the process jumps to step # 107, while step # 103 If the result of determination is not the phase difference AF only mode, contrast AF control is performed (# 105). In this contrast AF control, the photographic optical system 101 is controlled to be in focus based on the contrast information from the contrast AF circuit 253. The details of this contrast AF control will be described later with reference to FIGS.

Next, it is determined whether the release button 21 is fully pressed, that is, whether the 2R switch is turned on (# 107). If the result of determination is that it is not on, processing returns to step # 53 and the above steps are repeated. On the other hand, if it is on, the photographing operation is executed in step # 109 and thereafter.

When the shooting operation is started, the live view display is first stopped (# 109). Subsequently, the shutter 213 is closed (# 111). During live view display, the shutter 213 is opened and the subject image is displayed on the liquid crystal monitor 26 based on the output of the image sensor 221, but the shutter 213 is temporarily closed in order to start the photographing operation.

Next, it is determined whether or not the second focus display is being performed (# 113). In the contrast AF control subroutine, the first contrast AF control that guides the taking lens into the first focus allowable range and the second focus AF range that is narrower than the first focus allowable range. When the second contrast AF control can be executed and the second contrast AF control is completed, the second focus display is performed (# 277 in FIG. 11 and FIG. 15B). ). In step # 113, it is determined whether or not this highly accurate second in-focus state is reached.

In step # 113, if the second focus display is not being performed, it is determined whether or not the phase difference AF unnecessary condition is satisfied (# 115). The phase difference AF unnecessary conditions are as follows: (1) the focal length of the photographic lens is on the wide angle side from a predetermined value, (2) the aperture value is greater than or equal to a predetermined value (small aperture diameter), and (3) the subject distance is greater than the predetermined distance. This is a case where the depth of field is wider than the first focus allowable range due to the reason of being on the far side. That is, when these conditions are satisfied, it is considered that sufficient focusing accuracy can be obtained only by the first contrast AF control, so that it is not necessary to further perform highly accurate phase difference AF.

If the phase difference AF unnecessary condition is not satisfied in step # 115, it is determined whether or not the AF lock switch linked to the AF lock button 28 is on (# 117). If the result of determination is that the AF lock switch is not on, phase difference AF is performed in step # 119 and thereafter. That is, if all of the determination results in steps # 113, # 115, and # 117 pass N, high-precision AF is performed by phase difference AF.

In order to perform phase difference AF, first, the movable mirror 201 is returned and inserted into the optical path of the photographing optical system 101 (# 119). As a result, the subject light flux for phase difference AF is guided to the phase difference AF sensor 243. Subsequently, phase difference AF control is performed (# 121). In this step, the focus shift direction and the focus shift amount of the photographing optical system 101 are detected by a known phase difference AF, and the drive control of the optical system drive mechanism 107 is performed based on the focus shift direction and the focus shift amount. The system 101 is focused. Details will be described later with reference to FIG.

When the phase difference AF control is finished, the movable mirror 201 is moved to the raised position, that is, retracted (# 123). As a result, the subject light flux that has passed through the photographing optical system 101 is again guided to the image sensor 221 and forms an image on the image sensor 221.

If the result of determination in steps # 113 and # 115 described above passes both in Y, it is not necessary to perform high-precision AF by phase difference AF. Also, as a result of determination in step # 117, AF lock When the switch is on, the photographer has already determined the in-focus position, so that the in-focus position is not changed by the phase difference AF. The focus display is turned off (# 127). When step # 123 or step # 127 is completed, a shooting operation B for acquiring and recording image data based on the subject image is performed (# 125). This photographing operation B will be described later with reference to FIG. When the shooting operation B is completed, the process returns to step # 43, the live view display is resumed, and the above-described operation is repeated.

Next, a sub-routine of the photographing operation A in step # 37 will be described using FIG. This photographing operation A is a subroutine executed when the release button 21 is half-pressed in the normal optical viewfinder observation state (that is, non-live view display). When the shooting operation A subroutine is entered, first, shooting information display is turned off (# 131). Subsequently, as in step # 121, a phase difference AF control subroutine is executed (# 133). That is, the focus shift direction and the focus shift amount are obtained based on the output of the phase difference AF sensor 243, and the photographing optical system 101 is focused. Details of this subroutine will be described later with reference to FIG.

When the phase difference AF ends, photometry / exposure amount calculation is performed in the same manner as in step # 11, and exposure control values such as shutter speed and aperture value are obtained (# 135). Subsequently, it is determined whether or not the shutter button 21 has been fully pressed, that is, whether or not the 2R switch is on (# 137). If the result of determination is that the 2R switch is not on, it is determined whether or not the 1R switch is on (# 157). If the result of determination is that the 1R switch is not on, the shooting operation A is terminated and the original routine is returned to. On the other hand, if the result of determination is that the 1R switch is on, the flow returns to step # 137 to enter a standby state for detecting the state of the 1R switch and 2R switch.

If the result of determination in step # 137 is that the 2R switch is on, the routine proceeds to step for shooting. First, the movable mirror 201 is retracted (moved to the raised position) (# 139). As a result, the subject light flux by the photographing optical system 101 is guided onto the image sensor 221 to form an image. Subsequently, the lens CPU 111 is instructed to perform a narrowing operation (# 141), and the amount of narrowing is also instructed (# 143).

Now that the preparation for entering the imaging operation is completed, the exposure operation is started (# 145). In the exposure, the traveling of the front curtain of the shutter 213 is started and the charge accumulation of the image sensor 221 is started. When the time corresponding to the shutter speed obtained in step # 135 or the shutter speed manually set by the photographer has elapsed, the running of the rear curtain of the shutter 213 is started and the charge accumulation of the image sensor 221 is ended.

When the exposure operation ends, an instruction to open the aperture is output to the lens CPU 111 (# 147). Subsequently, the movable mirror 201 is returned to the lowered position (149), and the image signal is read from the image sensor 221 (# 151). Image processing of the read image signal is performed by the image processing circuit 257 or the like (# 153), and the processed image data is recorded on the recording medium 277 (# 155). When the image recording is completed, the original routine is restored.

Next, the subroutine of the photographing operation B in step # 125 (FIG. 6) will be described using FIG. This shooting operation B is a subroutine executed when the release button 21 is fully pressed in the live view display state. When the shooting operation B subroutine is entered, the exposure amount is calculated based on the output of the AE circuit 255 (# 161).

Subsequently, as in steps # 141 and # 143, a narrowing instruction is given and a narrowing amount is designated (# 163, # 165). Then, similarly to step # 145, an exposure operation is performed (# 167), whereby image data of the subject image is acquired based on the output of the image sensor 221. Thereafter, as in steps # 147, # 151, # 153, and # 155, the aperture is instructed to be opened (# 169), the image signal is read (# 171), the image processing is performed (# 173), and the recording medium 277 is recorded. (# 175). When the image recording is completed, the original routine is restored.

Next, the subroutine for phase difference AF control in step # 121 (FIG. 6) and step # 133 (FIG. 7) will be described with reference to FIG. In this phase difference AF control, the focus deviation direction and the amount of focus deviation of the photographing optical system 101 are obtained by a known phase difference method using the two light beams around the photographing optical system 101. It is possible to perform AF with high accuracy similar to high accuracy AF in contrast AF. When the subroutine for phase difference AF control is entered, it is first determined whether or not the enlarged display is being performed (# 180). That is, during live view display, the zoom display mode is entered in step # 55 (FIG. 4). In this state, the release button 21 is fully pressed (# 107), and it is determined whether or not the phase difference AF control subroutine is entered. To do. If the result of determination is that enlarged display is not in progress, all-point focus detection is performed (# 181).

In step 181, the defocus direction and defocus amount are detected for all points detectable by the phase difference AF sensor 243 and the phase difference AF processing circuit 245. On the other hand, as a result of the determination, when the enlarged display is being performed, the focal shift direction and the focal shift amount (defocus amount) are detected by the phase difference method for the points within the enlarged range. Points that can be measured by the phase difference AF method are positions (focus detection points 322) where “+” mark is given in the photographing screen 321 shown in FIG. 19A, and in this example, there are 11 points in total. is there. In step # 181, focus detection is performed for these all-focus detection points 322. Further, in the enlarged display mode, the live view display is displayed in an enlarged manner with respect to the enlarged area 323 indicated by a broken line in FIG. 19B, and by operating the cross button 30, for example, as shown in FIG. As described above, the enlarged region 323 indicated by the broken line moves. As the enlarged area 323 moves, the focus detection point 322 included in the enlarged area 323 also changes. In step # 182, when the release button 21 is fully pressed, focus detection (focus shift direction and focus shift amount) by the phase difference AF method is performed on the focus detection point 322 included in the enlarged display area.

When focus detection is completed in step # 181 or # 182, the closest point is selected from the detected points (# 183). In general, since the main subject is most often the closest subject, such a selection is performed. Next, based on the defocus amount at the selected closest point, it is determined whether or not the lens is within the focusing range (# 185). The criterion for determining whether or not the focus is within the focus range is based on whether or not the focus shift amount (defocus amount) is within a focus determination value based on the allowable circle of confusion. If the result of determination is within the in-focus range, the routine returns to the original routine. The permissible circle of confusion is set according to the imaging resolution of the image sensor 221, in other words, the cell size of the image sensor 221.

On the other hand, if the result of determination is not within the in-focus range, the driving direction for driving the imaging optical system 101 by the optical system driving mechanism 107 based on the focal shift direction and the focal shift amount of the selected focus detection point, and The drive amount is calculated (# 187). Then, the lens CPU 111 is instructed to perform lens drive control of the optical system drive mechanism 107 (# 189), and the lens drive amount and drive direction at that time are instructed (# 191).

When the body CPU 251 outputs a lens drive control instruction to the lens CPU 111, the body CPU 251 waits for a signal indicating completion of lens drive from the lens CPU 111 (# 193). When the lens driving is completed, focus detection is performed for the focus detection point selected in step # 183 (# 195). When focus detection ends, the process returns to step # 185, and the above steps are repeated until the focus range is entered.

Next, the contrast AF control subroutine in step # 105 (FIG. 6) will be described with reference to FIGS. In this contrast AF control, the photographing optical system 101 is driven so that the contrast information in the contrast AF circuit 253 based on the output of the image sensor 221 is maximized. This contrast AF control can be used when the movable mirror 201 is in the retracted position (upward position) and phase difference AF control based on the output of the phase difference AF sensor 243 cannot be performed. In contrast AF control, high-speed contrast AF (first contrast AF) that performs AF control with high speed but low focusing accuracy, and second focusing with low speed but high focusing accuracy. There are two modes of high-precision contrast AF (second contrast AF) for performing AF control with accuracy.

When the subroutine for contrast AF control is entered, first contrast AF is started, and first, 1 is set in the register DC (# 201). This register DC is a register used to determine the driving direction of lens driving. Subsequently, the lens extension direction is set as the lens driving direction (# 203). Then, the first predetermined value is set as the lens driving amount (# 205). The first predetermined value corresponds to the focus lens feed amount LD1 in FIG. 16A, and is an amount related to the defocus amount ΔfLCD corresponding to the permissible circle of confusion diameter φLCD on the liquid crystal monitor surface in FIG. is there.

Next, contrast information is acquired from the contrast AF circuit 253 (# 207). In this case, when performing non-enlarged live view display, contrast information of image data corresponding to the entire shooting screen is acquired. Further, when the 1R switch is turned on during enlarged display, the contrast information acquired here is performed based on image data cut out for enlarged display. The same applies to the contrast information acquired in step # 215, which will be described later. Subsequently, lens drive control is instructed to the lens CPU 111 (# 209), and the lens drive amount and drive direction set in steps # 203 and # 205 are transmitted (# 211). When these signals are transmitted, the lens CPU 111 drives the photographing optical system 101 by the optical system driving mechanism 107. When the drive control based on the set drive direction and drive amount ends, the lens CPU 111 transmits a lens drive completion signal to the body CPU 251.

The body CPU 251 waits for reception of the lens drive completion signal (# 213), and when received, acquires the latest contrast information from the contrast AF circuit 253 (# 215). Subsequently, it is determined whether or not the contrast has improved compared to the previous time (# 217). If the current contrast is improved as a result of the determination, 1 is added to the register DC (# 219), the process returns to step # 209, and the above steps are repeated.

If the result of determination in step # 217 is that the contrast is lower than the previous time, it is determined whether or not the value of the register DC is 1 (# 221). As a result of the determination, if the register DC is 1, the lens drive direction is reversed from the previous time (# 223), the process returns to step # 209, and the above steps are repeated.

That is, in the first lens driving, since the driving direction is unknown, the lens is once driven in the extending direction. As a result of driving, if the contrast is improved, the driving direction is correct (approaching the in-focus position), while if the contrast is decreasing, the driving direction is reverse (away from the in-focus position). It reverses because it is. Therefore, if the register DC is 1, it is determined that the driving is the first time and the process proceeds to step # 223, and the driving direction is reversed. On the other hand, if the register DC is not 1, it is determined that the contrast has exceeded the peak position. Proceed to # 225.

If the register DC is not 1 as a result of the determination in step # 221, the lens has been driven in a direction in which the contrast is improved, but since it has decreased here, it is determined that the contrast has passed the peak position. Then, the driving direction is changed to the opposite direction (# 225). Then, a second predetermined value is set as the lens driving amount (# 227).

The second predetermined value as the lens driving amount corresponds to half of the focus lens extension amount LD1 in FIG. Since it exceeds the peak position of the contrast, it is assumed that there is a peak position between the previous time and the current time, and is half of the first predetermined value. Subsequently, the lens CPU 111 is instructed to perform lens drive control (# 229), and the lens drive amount and drive direction set in steps # 225 and # 227 are transmitted (# 231).

When the lens CPU 111 receives a lens drive control instruction or the like, the lens CPU 111 starts drive control for the optical system drive mechanism 107 and transmits a lens drive completion signal to the body CPU 251 when driven by a drive amount based on the second predetermined value. To do. The body CPU 251 waits for reception of the lens drive completion signal (# 233), and when receiving the completion signal, performs a first in-focus display (# 235). This is displayed on the display surface of the liquid crystal monitor 26 as the first in-focus display 311 as shown in FIG.

The state in which the first in-focus display is performed is an in-focus state where the out-of-focus is inconspicuous if the subject image is confirmed on the liquid crystal monitor 26 even if it is inappropriate for photographing, and the in-focus tolerance is acceptable. The range is set by the allowable confusion circle diameter based on the display resolution of the liquid crystal monitor 26, that is, the display dot size of the liquid crystal monitor 26. Therefore, the focusing accuracy is sufficient for observing the subject image on the liquid crystal monitor 26.

Subsequently, it is determined whether or not the 2R switch is on (# 239). If the result of determination is that the 2R switch is on, the lens CPU 111 is instructed to request lens position information (# 241). The lens CPU 111 acquires lens position information from the optical system position detection mechanism 105 and transmits it to the body CPU 251. The body CPU 251 acquires the transmitted lens position information (# 243).

In step # 235, when the first in-focus display is made, the in-focus state is rough due to contrast AF control. In this state, if the release button 21 is not fully pressed, control is performed by the contrast AF control so that a more accurate in-focus state is achieved. However, when the release button 21 is fully pressed and the photographing operation is started, the process returns to Step # 107 in FIG. 6, and when a predetermined condition is satisfied, the focus control is performed by the phase difference AF control in Step # 121. The shooting operation B in step # 125 is performed. The lens position information is acquired in steps # 241 and # 243 in order to determine whether or not the phase difference AF unnecessary condition is satisfied in step # 115.

If it is determined in step # 239 that the 2R switch is not on, it is determined whether or not the 1R switch is on (# 245). If the result of determination is that the 1R switch is not on, processing returns to the original routine. However, if the 1R switch is on, contrast information is acquired for the second contrast AF (# 251, FIG. 11). ).

Subsequently, the same direction as the previous time is set as the driving direction (# 253), and a third predetermined value is set as the driving amount (# 255). This third predetermined value corresponds to the focus lens extension amount LD3 in FIG. 16B, and is related to the defocus amount Δfimg corresponding to the allowable circle of confusion diameter φimg on the imaging surface of the image sensor 211 in FIG. The amount to be.

Subsequently, lens drive control is instructed to the lens CPU 111 (# 257), and the lens drive amount and drive direction set in steps # 253 and # 255 are transmitted (# 259). The lens CPU 111 controls the optical system driving mechanism 107 to control driving of the photographing optical system 101. When the drive control is completed, a lens drive completion signal is transmitted to the body CPU 251. Therefore, the body CPU 251 is in a standby state until receiving this lens drive completion signal (# 261).

When the body CPU 251 receives the lens drive completion signal, it next acquires contrast information (# 263). Then, it is determined whether or not the contrast information has improved from the previous time (# 265). If the contrast is improved as a result of the determination, it is determined whether or not the 2R switch is on (# 285). If the result of determination is that the 2R switch is not on, it is determined whether or not the 1R switch is on (# 287).

If the result of determination in steps # 285 and # 287 is that the 2R switch is off and the 1R switch is on, the process returns to step # 257, and the above steps are repeated as long as the contrast is improved. On the other hand, if the 2R switch is on, or if the 2R switch and the 1R switch are off, the process jumps to step # 279, performs the processes of steps # 279 and # 281, and returns to the original routine. This defines the operation when the 2R switch is turned on when the second contrast AF is performed after the first focus display is performed. If the 2R switch is turned on, the second contrast AF is performed. The contrast AF is interrupted.

If the result of determination in step # 265 is that the contrast has decreased, the driving direction is set opposite to the previous driving direction (# 267), and a fourth predetermined value is set as the driving amount (# 269). The fourth predetermined value as the lens drive amount corresponds to half of the focus lens extension amount LD3 in FIG. Since it exceeds the peak position of the contrast, it is assumed that there is a peak position between the previous time and the current time, and is half of the third predetermined value.

Subsequently, the lens CPU 111 is instructed to perform lens drive control (# 271), and the lens drive amount and drive direction set in steps # 267 and # 269 are transmitted (# 273). When the lens CPU 111 receives a lens drive control instruction or the like, the lens CPU 111 performs drive control by the optical system drive mechanism 107, and transmits a drive completion signal to the body CPU 251 when the drive control is completed. The body CPU 251 waits to receive this lens drive completion signal (# 275), and when receiving the drive completion signal, the body CPU 251 displays the second in-focus display (# 277).

In this display, as shown in FIG. 15B, a first in-focus display 311 and a second in-focus display 312 are displayed on the display surface of the liquid crystal monitor 26. The state in which the second in-focus display 312 is displayed is a highly accurate in-focus state equivalent to the permissible circle of confusion of the pixels of the image sensor 221, and is also in the same degree as the in-focus accuracy in the phase difference AF. is there. Once the second in-focus display 312 is performed, a lens position information request is instructed in the same manner as in step # 241 (# 279), and lens information is acquired in the same manner as in step # 243 (# 281). Return to the routine.

In this embodiment, when the contrast peak position is passed, the drive amount is halved and the drive is performed in the reverse direction (# 225, # 227, # 267, # 269). You may make it move to the peak position of contrast by interpolation calculations, such as a three-point interpolation method.

As described above, in the present embodiment, when the enlarged display is performed in the live view display mode (# 55 → # 75), the release button is fully pressed (# 53Y → # 107Y), and the shooting operation is started. The focus shift amount is detected by the phase difference AF method at the focus detection point (# 182) included in the enlarged region. For this reason, it is possible to perform automatic focus adjustment on a region where the photographer has performed an enlarged display, that is, an object that the photographer wants to focus on. Further, since it is not necessary to perform the phase difference AF for all the focus detection points, the distance measurement time can be shortened, and furthermore, high precision focusing accuracy can be ensured by the phase difference AF.

In the present embodiment, after contrast AF is performed in step # 105, phase difference AF is performed in step # 121. In contrast AF, focus adjustment is performed at least at high speed and with coarse focusing accuracy, and then high-precision phase difference AF is performed in step # 121. Although the focusing accuracy of the contrast AF is rough (the first focusing accuracy), it is in the in-focus state, so it takes a long time to complete the high-precision focus adjustment from the in-focus state. Therefore, the time lag is small and high-precision focus adjustment can be performed.

Further, in the determination of step # 113 in the present embodiment, when the second in-focus display is made, that is, when the high-precision contrast AF is in focus, the phase difference AF in step # 121 is omitted. is doing. That is, in the present embodiment, the first focus adjustment mode in which focus adjustment is performed by a combination of high-speed contrast AF and phase difference AF, and the second focus adjustment mode in which focus adjustment is performed by high-precision contrast AF after high-speed contrast AF. However, by omitting the phase difference AF, the time lag can be shortened by the time required for the phase difference AF. Further, in the high-precision contrast AF, the focus adjustment can be performed with the same high accuracy as the phase difference AF, and sufficient focusing accuracy can be ensured. In addition, when the release button 21 is half-pressed during the enlarged display and the automatic focus adjustment by the contrast AF is performed and the second in-focus display is performed, sufficient focus accuracy is obtained. The phase difference AF is omitted, and the time required for automatic focusing is shortened.

Further, in step # 115 in the present embodiment, an unnecessary condition for phase difference AF is determined, and when this unnecessary condition is met, the phase difference AF in step # 121 is omitted. For this reason, the time lag can be shortened by the time required for the phase difference AF, and high-precision focus adjustment can be performed. In the present embodiment, three conditions are used as unnecessary conditions for phase difference AF. However, the present invention is not limited to this, and other requirements may be added, or any of the requirements may be omitted. Also good. In any case, the phase difference AF can be omitted as long as sufficient focusing accuracy is obtained without performing the phase difference AF with high accuracy.

Further, in step # 117 in this embodiment, it is determined whether or not AF lock is performed. If AF lock is performed, the phase difference AF in step # 121 is omitted. For this reason, the time lag can be shortened by the time required for the phase difference AF. In particular, when the AF lock is performed, the photographer has already determined the in-focus position, and often wants to shoot quickly, and at least the first in-focus display is provided. Temporary focusing accuracy can be ensured. In the present embodiment, the phase difference AF is omitted when the AF lock button 28 is operated. However, not only the AF lock button 28 but also the phase difference AF is operated when another operation member is operated. May be omitted.

Next, the focusing accuracy of contrast AF in the present embodiment will be described with reference to FIGS. As shown in FIG. 17A, the pixels on the imaging surface of the imaging element 221 are 3648 pixels in the horizontal direction and 2738 pixels in the vertical direction. On the other hand, when the liquid crystal monitor surface of the liquid crystal monitor 26 is composed of 640 pixels in the horizontal direction and 320 pixels in the vertical direction as shown in FIG. Is about 1/7, and even if the LPF coefficient is taken into consideration, it is about 1/4.
φLCD = (3648/640) * φimg / α
≒ 4 * φimg
It becomes.

The allowable defocus amount ΔfLCD for the liquid crystal monitor corresponding to the allowable confusion circle diameter φLCD of the liquid crystal monitor 26 is
ΔfLCD = φLCD / F
F: Lens aperture value (FNo.)
F = D / f (D: aperture, f: focal length)

Accordingly, the focusing accuracy in the first focus display (# 235) is such that the driving amount is the first predetermined value, and as this first predetermined value, as shown in FIG. By adopting β * ΔfLCD, it is possible to obtain the focusing accuracy of the permissible circle of confusion diameter φLCD of the liquid crystal monitor 26. Here, β≈5 to 15 (β is an empirical value).

On the other hand, as shown in FIG. 17A, the imaging surface (light receiving surface) of the imaging element 221 is composed of 3648 pixels in the horizontal direction and 2838 pixels in the vertical direction. The allowable confusion circle diameter φimg of the image sensor 221 is
φimg = α * X
Where α: LPF coefficient (= 1.5-2)
X: Cell size. Since the LPF coefficient is a coefficient due to the influence of the infrared cut filter / low-pass filter 217, the allowable confusion circle diameter φimg of the image sensor 221 is obtained by multiplying the pixel size of the image sensor by a coefficient considering the low-pass filter. Is obtained.

Then, the allowable defocus amount Δfimg for imaging corresponding to the allowable confusion circle diameter φimg of the image sensor 221 is
Δfimg = φimg / F
F: Lens aperture value (FNo.)
F = D / f (D: aperture, f: focal length)

Therefore, the focusing accuracy in the second focus display (# 277) is such that the driving amount is the second predetermined value, and γ * Δfimg is adopted as the second predetermined value as shown in FIG. For example, it is possible to obtain a focusing accuracy of about the allowable confusion circle diameter φimg of the image sensor 221. Here, γ≈3 (γ is an empirical value). Note that the number of pixels described individually is an example, and an allowable circle of confusion, a defocus amount, and a drive amount may be determined according to the design value of the photographing apparatus here. Note that the focus allowable range in the phase difference AF is also determined based on Δfimg.

Next, the operation of the interchangeable lens 100 in the lens CPU 111 will be described with reference to FIG. First, it is determined whether or not a lens information request instruction has been issued from the body CPU 251 (# 301). If the request is instructed as a result of the determination, lens information is transmitted (# 311). The lens information here is information unique to the lens such as an open aperture value, a minimum aperture value, lens color balance information, aberration information, information for AF, and the like. This is information stored in a rewritable memory.

If the result of determination in step # 301 is not a lens information request instruction, it is determined whether or not lens position information is requested (# 303). If it is determined that the position information is requested, the lens position information is transmitted to the body CPU 251 (# 313). Since the lens position information is detected by the optical system position detection mechanism 105, this information is transmitted.

If the result of determination in step # 303 is not a position information request instruction, it is determined whether or not it is a narrowing instruction (# 305). If the result of the determination is a narrowing instruction, the narrowing amount transmitted from the body CPU 251 is subsequently received (# 315). When the aperture amount is received, the aperture drive mechanism 109 controls the aperture drive of the aperture 103 (# 317).

If the result of determination in step # 305 is not a narrowing-down instruction, it is determined whether or not it is an opening instruction (# 307). If the result of the determination is an aperture opening instruction, the aperture opening drive control of the aperture 103 performed by the aperture driving mechanism 109 is controlled (# 317).

If the result of determination in step # 307 is that there is no aperture opening instruction, it is determined whether or not it is a lens drive control instruction (# 309). If the result of the determination is a lens drive control instruction, the lens drive amount and drive direction transmitted subsequently are received (# 321). When the lens driving amount and the driving direction are received, the lens CPU 111 controls the optical system driving mechanism 107 to control the photographing optical system 101 (# 323). When a predetermined driving amount is driven, a lens driving completion signal is transmitted to the body CPU 251 (# 325).

As described above, in the embodiment of the present invention, the subject luminous flux incident through the imaging optical system 101 is received by the imaging surface, and the subject image formed on the imaging surface is photoelectrically converted to output subject image data. The image sensor 221 that performs the live view display using the subject image data acquired by the image sensor 221 and the live view display operation while obtaining the contrast information of the subject image from the subject image data. Contrast AF means (contrast AF circuit 253, etc., # 105 contrast AF control) for guiding the photographing optical system 101 within a predetermined focusing allowable range (first focusing range) based on the contrast information, and a plurality of images in the photographing screen Including a phase difference AF sensor 243 for detecting the amount of defocus of the photographing optical system 101 by a phase difference method. Phase difference AF means (phase difference AF sensor) that guides the photographing optical system 101 within a focus allowable range narrower than a focus allowable range of the contrast AF means in accordance with any of a plurality of focus shift amount information detected by the sensor 243 243, phase difference AF processing circuit 245) and the release button 21 is pressed halfway during the live view display operation (# 53Y), the focus adjustment operation by the contrast AF means is executed (# 53Y). # 105) After that, when the release button 21 is fully pressed (# 107), the control means (body CPU 251) for controlling to execute the focus adjustment operation (# 121) by the phase difference AF means. It has. The liquid crystal monitor 26 can enlarge and display a part of the photographing screen (enlarged display mode, see FIG. 13), and the phase difference AF means is included in the enlarged area in the state where the enlarged live view display is performed. The focus shift amount is detected at the focus detection point (FIGS. 19B and 19C) (# 182).

Further, in the embodiment of the present invention, an image sensor that receives a subject luminous flux incident via the photographing optical system 101 on the imaging surface, photoelectrically converts the subject image formed on the imaging surface, and outputs subject image data. 221, a liquid crystal monitor 26 that performs live view display using the subject image data acquired by the image sensor 221, and a portion of the subject image data is cut out according to the operation of the enlargement button 34, and an enlarged display is displayed on the liquid crystal monitor 26. An enlarged display means (pre-processing circuit 225, # 55 to # 75) to be performed, and a phase difference AF sensor 243 for detecting a focal shift amount of the photographing optical system 101 at a plurality of points in the photographing screen by a phase difference method, Phase difference AF means (phase difference AF sensor 243, phase difference) that guides the photographing optical system 101 to within the focus allowable range in accordance with any of a plurality of pieces of defocus amount information detected by the sensor 243. And it includes an AF processing circuit 245, etc.). When the release button 21 is operated, the focus detection point existing in the range where the enlarged display has been performed by the enlarged display means (see FIGS. 19B and 19C), the focus shift by the phase difference AF means. The amount is detected (# 182), and the focus adjustment operation of the photographing lens is performed based on the detection result (# 185 to # 195).

As described above, in the present embodiment, the focus shift amount is detected by the phase difference AF method at the focus detection point included in the enlarged display area, and the subject intended by the photographer is focused. be able to. In addition, the distance measurement time can be shortened by performing distance measurement for all focus detection points.

In this embodiment, the subject luminous flux is switched between the finder optical system and the image pickup device by moving the movable mirror 201 up and down. However, the present invention is not limited to this, and a half mirror is arranged to distribute the subject luminous flux. May be. In addition, although the focusing accuracy by the phase difference AF is approximately the same as the accuracy at the time of the second focusing display by the high-precision contrast AF, the focusing accuracy is not limited to this, and any focusing accuracy is higher. Also good. However, the focusing accuracy by the phase difference AF is higher than the system for the first focusing display in the high-speed contrast AF. Furthermore, in the phase difference AF control subroutine, the closest point is selected from among the focus detection points (# 183). However, the present invention is not limited to this, and an intermediate value of a plurality of focus detection results may be selected. In addition, a plurality of focus detection results may be appropriately processed by an evaluation calculation.

In this embodiment, an example in which a single-lens reflex camera is applied as a digital camera has been described. However, the present invention can perform live view display and can perform focus adjustment by switching between contrast AF and phase difference AF. It can be applied to an electronic imaging device such as

It is the external appearance perspective view which looked at the digital single-lens reflex camera in one Embodiment of this invention from the back. 1 is a block diagram illustrating an overall configuration of a digital single-lens reflex camera according to an embodiment to which the present invention is applied. It is a flowchart which shows the operation | movement of the power-on reset in the camera main body side in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the live view display in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the live view display in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the live view display in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the imaging | photography operation | movement A in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the imaging operation B in one Embodiment of this invention. It is a flowchart which shows the operation | movement of phase difference AF control in one Embodiment of this invention. It is a flowchart which shows the operation | movement of contrast AF control in one Embodiment of this invention. It is a flowchart which shows the operation | movement of contrast AF control in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the power-on reset in the interchangeable lens side in one Embodiment of this invention. It is a figure which shows the display state in the liquid crystal monitor in the enlarged display mode in one Embodiment of this invention, (A) shows a full-screen display state, (B) shows an enlarged display state, (C) is an enlarged range. (D) shows the enlarged part in (B), (E) is a figure which shows the enlarged part in (C). It is a figure which shows the menu display screen of AF mode setting in one Embodiment of this invention. It is a figure which shows the focus completion display in one Embodiment of this invention, (A) shows a 1st focus display, (B) is a figure which shows a 2nd focus display. It is a figure which shows the contrast information and drive relationship of a focus lens in one Embodiment of this invention, (A) is a case of high-speed contrast AF, (B) is a figure which shows the case of high-precision contrast AF. It is a figure explaining the permissible circle of confusion of the image sensor and liquid crystal monitor in one embodiment of the present invention, (A) shows the permissible circle of confusion of the image sensor, and (B) shows the permissible circle of confusion of the liquid crystal monitor Show. It is a figure which shows the relationship between the allowable confusion circle diameter and defocus amount in one Embodiment of this invention. It is a figure which shows notionally the relationship between the focus detection point and expansion range in one Embodiment of this invention.

Explanation of symbols

21 ... Release button, 22 ... Shooting mode dial, 24 ... Information setting dial, 26 ... LCD monitor, 27 ... Continuous / single-shot button, 28 ... AF lock button, 30 ... Cross button, 30U ... Cross button for up, 30D ... Cross button for down, 30R ... Cross button for right, 30L ... Cross button for left, 31 ... OK button, 33 ..Live view display button 34... Enlarge button 37. Menu button 38. Play button 40. Media loading lid 50. Strobe 100. Interchangeable lens 101 ...... Optical optical system 103 ... Aperture 105 ... Optical system position detection mechanism 107 ... Optical system drive mechanism 109 ... Aperture drive mechanism 111 ... Lens CPU 200 ...・ Camera body, 201 ... movable mirror, 203 ... sub 205, focusing screen, 207 ... pentaprism, 211 ... photometric sensor, 213 ... focal plane shutter, 215 ... dust filter, 216 ... piezoelectric element, 217 ... red Outer cut filter / low-pass filter, 221... Image sensor, 223... Image sensor drive circuit, 225... Pre-processing circuit, 227. Shift mechanism drive circuit, 233 ... Shift mechanism, 235 ... Dust-proof filter drive circuit, 237 ... Movable mirror drive mechanism, 241 ... Photometric processing circuit, 243 ... Phase difference AF sensor, 245 ... Phase difference AF processing circuit, 250... ASIC, 251... Sequence controller (body CPU), 252. Bus, 253 ... Contrast AF circuit, 255 ... AE circuit, 257 ... Image processing circuit, 259 ... Compression / decompression circuit, 261 ... Video signal output circuit, 263 ... Liquid crystal monitor drive circuit 265 ... SDRAM detection circuit, 267 ... SDRAM, 271 ... input / output circuit, 273 ... communication circuit, 275 ... recording medium control circuit, 277 ... recording medium, 279 ... Flash memory control circuit, 281 ... flash memory, 283 ... switch detection circuit, 285 ... various switches, 300 ... communication contact, 311 ... first focus display, 312 ... second Focus display, 321 ... Shooting screen, 322 ... Focus detection point, 323 ... Enlarged area

Claims (5)

Imaging means for receiving a subject luminous flux incident through a photographing lens on an imaging surface, photoelectrically converting a subject image formed on the imaging surface and outputting subject image data;
Display means for performing live view display operation using subject image data acquired by the imaging means;
Contrast AF means for obtaining the contrast information of the subject image from the subject image data while performing the live view display operation, and guiding the photographing lens within a predetermined focus allowable range based on the contrast information;
A sensor that detects a focal shift amount of the photographing lens with respect to a plurality of points in the photographing screen by a phase difference method, and the contrast of the photographing lens according to any one of the plurality of focal shift amount information detected by the sensor A phase difference AF unit that leads to a focus allowable range narrower than a focus allowable range of the AF unit;
When a half-press operation of the release button is performed during execution of the live view display operation, a focus adjustment operation is performed by the contrast AF means, and then a full-press operation of the release button is performed. Control means for controlling the focus adjustment operation by the phase difference AF means,
It has
The display means can enlarge and display a part of the photographing screen, and the phase difference AF means can detect the focus detection point included in the enlargement area when the enlarged live view display is performed. An imaging apparatus for detecting the focus shift amount.   If the release button is pressed halfway while the enlarged live view display is performed, which cuts out a part of the subject image data and performs live view display, the focus of the taking lens is determined based on the contrast information of the extracted subject image data. After adjusting the release button, if the release button is fully pressed, the focus detection point of the photographing lens is detected by the phase difference method for the focus detection point existing in the cut-out range, and the detection result is based on the detection result. A method for controlling a photographing apparatus, comprising performing a focus adjustment operation of a photographing lens. Imaging means for receiving a subject luminous flux incident through a photographing lens on an imaging surface, photoelectrically converting a subject image formed on the imaging surface and outputting subject image data;
Display means for performing live view display operation using subject image data acquired by the imaging means;
An enlarged display means for cutting out a part of the subject image data and performing an enlarged display on the display means in response to an operation of an enlargement operation member;
A sensor that detects a focal shift amount of the photographing lens with respect to a plurality of points in the photographing screen by a phase difference method, and the photographing lens is within an in-focus tolerance range based on a plurality of focal deviation amount information detected by the sensor. Phase difference AF means leading to
It has
When the release button is operated, a focus shift amount is detected by the phase difference AF means for the focus detection point existing in the range where the enlarged display is made by the enlargement display means, and based on the detection result. A photographing apparatus for performing a focus adjustment operation of the photographing lens. First contrast AF means for obtaining contrast information of the subject image from the subject image data acquired by the imaging means, and for guiding the photographing lens within a first allowable focus range based on the contrast information;
With
In response to the half-pressing operation of the release button, the first contrast AF means performs the focus adjustment operation of the photographing lens within the first focus allowable range, and in this state, the release button is fully pressed. 4. The photographing apparatus according to claim 3, wherein a focus adjustment operation is performed by the phase difference AF unit when the phase difference AF unit is used. Second contrast AF means for guiding the photographing lens to a second focus allowable range narrower than the first focus allowable range based on the contrast information;
With
In response to the half-pressing operation of the release button, after the focus adjustment operation of the photographing lens is performed within the first focus allowable range, the focus of the photographing lens is further within the second focus allowable range. 5. The photographing apparatus according to claim 4, wherein the focus adjustment operation by the phase difference AF means is prohibited when the release button is fully pressed in a state where the adjustment operation is performed.