JP2017021177A - Range-finding point upon lens vignetting, range-finding area transition method - Google Patents

Abstract

Lens vignetting is determined, and transition control of a focus detection frame and a focus detection region is performed.
A phase difference method digital camera capable of detecting a focus adjustment state of a photographing optical system in a plurality of focus detection regions, and a control unit 223 uses an entrance pupil of the focus detection optical system as an exit pupil of the photographing optical system. A pattern storage unit 223 for storing a pattern of the included focus detection area; a specific pattern stored in the pattern storage unit 223 is selected; and a focus adjustment state in the focus detection area corresponding to the specific pattern A focus detection mode selection means 223 for selecting a focus detection mode, a focus detection position determination means 223 for determining a focus detection position designated in the selected focus detection mode, When the focus detection area changes, it has vignetting determination means 223 for determining whether the focus detection position is included in the focus detection area. When it is constant, it changes the focus detection position.
[Selection] Figure 1

Description

  The present invention relates to a focus detection device, an imaging device, and a camera system, and is particularly suitable for a camera system when vignetting occurs due to a photographing optical system such as a lens.

  Recently, many photographic cameras or video cameras have an automatic focusing function for automatically adjusting the focus of an objective lens (photographing lens). In particular, a focus detection device using a phase difference detection method is generally used for a single-lens reflex camera that requires strict focus accuracy. This phase difference detection method receives a pair of light intensity distributions from different regions of the pupil of the photographing optical system by a pixel array (line sensor array) of the light intensity conversion element, and adjusts the focus of the objective lens from the relative positional relationship of both light intensity distributions This is a method for detecting a state.

  This focus detection method allows defocus detection regardless of the focal length of the photographic lens, and the size of the field of focus detection is fixed regardless of the focal length of the photographic lens. It is suitable for a camera system of the type. In recent years, a phase difference detection type focus detection apparatus having a plurality of focus detection fields has been commercialized.

  However, this phase difference detection method includes a pair of entrance pupils with a predetermined F value (F number) at a predetermined position on the optical axis determined by the optical system on the focus detection side. Vignetting may occur in the detected light beam. That is, when the F value (F number) of the photographing optical system is larger than the predetermined F value, vignetting occurs in the focus detection light beam, and when an interchangeable lens whose pupil of the photographing optical system is different from the predetermined position is attached. If vignetting occurs in a part of the focus detection light beam, the focus detection accuracy is significantly reduced.

  In order to improve this influence, in Patent Document 1, vignetting of a focus detection light beam is determined. When vignetting does not occur, AF control is performed with phase difference AF, and when vignetting occurs, contrast AF is performed. AF control is performed.

  Further, in Patent Document 2, a focus detection light beam is determined, and a focus detection region is appropriately set according to a change in the focus detection light beam.

JP 2007-248782 JP Japanese Unexamined Patent Publication No. 2014-10284

  In the prior art disclosed in Patent Document 1, there is a disclosure about a method of detecting a focus by switching a phase difference AF method and a contrast AF method by vignetting of a focus detection light beam by a lens, but by vignetting of a focus detection light beam by a lens, There is no disclosure of a method for determining a region where focus detection is possible by phase difference AF and further performing transition control of the focus detection frame and focus detection region.

  Even in the prior art disclosed in Patent Document 2, there is a disclosure of determining a region where focus detection is possible by phase difference AF by vignetting of a focus detection light beam by a lens, but further, transition control of a focus detection frame and focus detection region There is no disclosure of how to do this.

  Accordingly, an object of the present invention is to determine an area where focus detection is possible based on the characteristics of the focus detection light beam by the lens in advance, thereby detecting lens attachment / detachment, determining vignetting, and detecting the focus detection frame and the focus detection area. The transition control is performed, and the transition of the focus detection mode for setting the focus detection frame and the focus detection area is made easy to understand.

The digital camera according to the present invention is a phase difference type digital camera (200) capable of detecting the focus adjustment state of the photographing optical system in a plurality of focus detection regions, and the light beams that have passed through different regions of the exit pupil of the photographing optical system. Is calculated based on the focus adjustment state of the photographing optical system based on the output of the focus detection optical system, the AF sensor (204) that receives the light flux from the focus detection optical system, and the AF sensor (204). Control means (223), and the control means (223) converts the pattern of the focus detection area in which the entrance pupil of the focus detection optical system is included in the exit pupil of the imaging optical system into the F of the imaging optical system. Pattern storage means (223) for storing the value and information relating to the exit pupil position of the photographing optical system is provided, and the control means (223) provides the F value of the photographing optical system and the photographing Based on the information about the exit pupil position of the optical system, a specific pattern stored in the pattern storage means (223) is selected, and detection of the focus adjustment state is allowed in the focus detection area corresponding to the external specific pattern. It is characterized by
A focus detection mode determination means (223) for determining a focus detection mode selectable in the focus detection area, a focus detection mode selection means (223) for selecting a focus detection mode,
Focus detection position determination means (223) for determining a focus detection position designated in the selected focus detection mode;
Vignetting determination means (223) for determining whether the focus detection position is included in the focus detection area when the focus detection area changes,
When it is determined that vignetting has occurred, the focus detection position is changed.

  According to the digital camera of the present invention, an area where focus detection is possible is determined in advance based on the characteristics of the focus detection light beam by the lens, thereby detecting the attachment / detachment of the lens, determining vignetting, It is possible to perform transition control of the detection area.

  Furthermore, it is possible to make the transition of the focus detection mode for setting the focus detection frame and the focus detection area easy to understand.

Digital camera block diagram Illustration of the principle of defocus amount detection Illustration of the principle of defocus amount detection Illustration of the principle of vignetting (A) Explanation of focus detection area and focus detection mode in the absence of luminous flux vignetting (b) Explanation of focus detection area and focus detection mode in the presence of luminous flux vignetting (A) (b) (c) Explanatory drawing of operation | movement of the focus detection area | region in zone focus detection mode which is one of focus detection modes. Explanatory drawing of the change sequence of the focus detection frame of Example 1. FIG. Explanatory drawing of the change sequence of the focus detection frame of Example 2. FIG. Explanatory drawing of a focus detection area and a focus detection mode when the automatic focus detection mode is changed in a state where there is vignetting of the luminous flux Explanatory drawing of the change sequence of the focus detection frame of Example 3.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Example 1]
The focus detection frame changing method according to the first embodiment of the present invention will be described below with reference to the drawings.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of a digital camera 200 according to the present embodiment. In FIG. 1, a lens unit 100 is a lens unit on which a replaceable photographic lens is mounted.

  The digital camera 200 is detachably attached to the taking lens unit 100 via a mount mechanism (not shown). The mount unit includes an electrical contact group 107, which communicates between the digital camera 200 and the photographing lens unit 100 to drive the lens 101 and the diaphragm 102 of the photographing lens.

  A photographing light beam from a subject image (not shown) is guided to a quick return mirror 202 via a photographing lens 101 and a diaphragm 102 which is an exposure control means for adjusting the amount of light. A central portion of the quick return mirror 202 is a half mirror, and is configured such that a part of the subject light flux is transmitted at a position where the quick return mirror 202 is down. The subject luminous flux that has passed through the quick return mirror 202 is reflected by the sub-mirror 203 installed behind the quick return mirror 202 and guided to the AF sensor 204 that is an automatic focus adjusting means.

  On the other hand, the photographing light beam reflected by the quick return mirror 202 forms an image on the focus plate 250. The image formed on the focus plate 250 reaches the eyes of the photographer through the pentaprism 201 and the eyepiece lens 206.

  A transmissive liquid crystal 251 is disposed between the focus plate 250 and the pentaprism 201, and the transmissive liquid crystal 251 displays a plurality of distance measuring points. As a result, the photographer can view the subject image on the focus plate 250 and a plurality of distance measuring points in a superimposed manner. Further, when the quick return mirror 202 is raised, the light flux from the photographing lens 101 is an image pickup unit represented by a CMOS or the like as an image pickup device via a filter 209 and a focal plane shutter 208 which is a mechanical shutter. The image sensor 210 is reached. The filter 209 has two functions, one is a function of cutting infrared rays and guiding only visible light to the image sensor 210, and the other is an optical low-pass filter for cutting high-frequency components of subject light. As a function. The focal plane shutter 208 includes a front curtain and a rear curtain, and is a light shielding unit that controls transmission and blocking of a light beam from the photographing lens 101.

  The sub mirror 203 is configured to be folded when the quick return mirror 202 is up. In addition, the digital camera 200 includes a system controller 223 configured by a CPU that serves as a control unit for the entire digital camera, and appropriately controls the operation of each unit described below.

  The system controller 223 includes a lens control circuit 104 that controls a lens driving mechanism 103 for moving the photographing lens 101 in the optical axis direction and performing focusing, and an aperture driving mechanism 105 for driving the aperture 102. The aperture control circuit 106 to be controlled, the up / down drive of the quick return mirror 202, the shutter charge / mirror drive mechanism 211 for controlling the shutter charge drive of the focal plane shutter 208, the front curtain and the rear of the focal plane shutter 208 A shutter control circuit 212 for controlling the running of the curtain, a photometric circuit 207 which is a split photometric means for performing automatic exposure control connected to a photometric sensor disposed in the vicinity of the eyepiece 206, and the digital Parameters that need to be adjusted to control the camera 200 EEPROM222 focus detection area corresponding to the lens ID information and the lens ID is a storage means stored is connected.

  The EEPROM 222 stores constants for operating the system controller 223, programs, and the like. Here, the program is a program for executing various flowcharts described later in the present embodiment.

  The system controller 223 controls the entire digital camera 200. By executing the program recorded in the above-described EEPROM 222, each process of this embodiment to be described later is realized. In the DRAM 221, constants and variables for operating the system controller 223, programs read from the EEPROM 222, and the like are expanded.

  The lens control circuit 104 stores information unique to the lens, for example, information such as focal length, wide aperture, lens ID assigned to each lens, lens type, manufacturer information, lens status, and information received from the system controller 223. It also has storage means.

  An external control device 300 represented by a personal computer (PC) can be connected to the digital camera 200, and the personal computer 300 and the system controller 223 can communicate with each other via a communication interface circuit 224. ing.

  The photometric sensor connected to the photometric circuit 207 is a sensor for measuring the luminance of the subject, and its output is supplied to the system controller 223 via the photometric circuit 207. The photometry circuit 207 is an automatic exposure adjustment unit.

  Further, the system controller 223 controls the lens driving mechanism 103 via the lens control circuit 104 to form a subject image on the image sensor 210. Further, the system controller 223 controls the aperture driving mechanism 105 that drives the aperture 102 via the aperture control circuit 106 based on the Av value set in the photographing mode, and further, based on the set Tv value. A control signal is output to the shutter control circuit 212.

  The drive source of the front and rear curtains of the focal plane shutter 208 is a spring, and after the shutter travels, a spring charge is required for the next operation. The shutter charge / mirror drive mechanism 211 is configured to control this spring charge. Further, the click return mirror 202 is raised and lowered by the shutter charge / mirror drive mechanism 211.

  An image data controller 220 is connected to the system controller 223. The image data controller 220 is correction data sampling means and correction means constituted by a DSP (digital signal processor), and controls the image sensor 210 and corrects or processes image data input from the image sensor 210. Is executed based on a command from the system controller 223. Auto white balance is also included in the image data correction and processing items. Auto white balance is a function that corrects a portion of maximum brightness in a captured image to a predetermined color (white). In auto white balance, the correction amount can be changed by a command from the system controller 223.

  The image data controller 220 receives a timing pulse generation circuit 217 that outputs a pulse signal necessary for driving the image sensor 210, and a timing pulse generated by the timing pulse generation circuit 217 together with the image sensor 210. An A / D converter 216 for converting an analog signal corresponding to a subject image output from the image sensor 210 into a digital signal, a DRAM 221 for temporarily storing the obtained image data (digital data), and D The / A converter 215 and the image compression circuit 219 are connected.

  The DRAM 221 is used as a storage means for temporarily storing image data before processing or data conversion into a predetermined format.

  The D / A converter 215 is connected to an image display circuit 213 as image display means via an encoder circuit 214. Further, the image compression circuit 219 is connected to an image data recording medium 218 which is a recording means.

  The image display circuit 213 is a circuit for displaying image data picked up by the image sensor 210, and is generally composed of a color liquid crystal display element.

  The image data controller 220 converts the image data on the DRAM 221 into an analog signal by the D / A converter 215 and outputs the analog signal to the encoder circuit 214. The encoder circuit 214 converts the output of the D / A converter 215 into a video signal (for example, NTSC signal) necessary for driving the image display circuit 213.

  The image compression circuit 219 is a circuit for performing compression and conversion (for example, JPEG) of image data stored in the DRAM 221. The converted image data is stored in the image data recording medium 218. As this recording medium, a hard disk, a flash memory, a floppy (registered trademark) disk, or the like is used.

  Further, the system controller 223 includes an operation display circuit 225 for displaying operation mode information and exposure information (such as shutter speed, aperture value, etc.) of the digital camera 200, and photographing preparation operations such as photometry and distance measurement. Release SW1 (231) for starting, release SW2 (230) for starting an imaging operation, mode setting SW229 for setting a mode for causing the digital camera to perform a desired operation by the user, image selection means, The determination SW 227, which is various setting means such as menu settings, and the parameters are displayed up and down by rotating operation.

  Alternatively, an electronic dial SW226 for moving the focus detection frame, a menu SW236, a reproduction SW237, and an enlargement / reduction SW238 are connected. For example, when the menu SW 236 is pressed, various settable menu screens are displayed on the image display circuit 213. Various settable menu screens include a focus detection frame selection screen for selecting a focus detection frame. The user can make various settings such as menu settings intuitively using the menu screen displayed on the image display circuit 213 and the electronic dial SW 226 and the determination SW 227.

  Further, for example, when the playback SW 237 is pressed, various settable playback screens are displayed on the image display circuit 213. Further, the image data recorded on the image data recording medium 218 is displayed on the reproduction screen. When the enlargement / reduction SW 238 is pressed in the reproduction screen, the image is enlarged or reduced and displayed on the image display circuit 213. The user intuitively performs various settings such as image sending, designation of an enlargement position, enlargement / reduction, and the like using the reproduction screen displayed on the image display circuit 213 and the electronic dial SW226, determination SW227, and enlargement / reduction SW238. Can do.

(Explanation of defocus detection principle)
Next, the principle of defocus amount detection (focus position shift amount detection) will be described with reference to FIGS. FIG. 2 is a diagram showing a focus position on the image sensor and a focus position shift. As shown in FIG. 2, when the image sensor is in focus, the interval between the two images on the line sensor takes a certain value. This value can be obtained by design, but in practice, it does not become the same as the design value due to the size, variation and assembly error of parts. Therefore, it is difficult to obtain the two-image interval (reference two-image interval Lo) unless actually measured. If the two image interval is narrower than the reference two image interval Lo, it is a front pin, and if it is wider than Lo, it is a rear pin.

  FIG. 3 is a view showing a model in which the condenser lens is omitted from the optical system of the AF sensor module. As shown in FIG. 3, when the chief ray angle is θ, the separator lens magnification is β, and the image movement amounts are ΔL and ΔL ′, the defocus amount L can be obtained by the following equation.

  Here, β tan θ is a parameter determined by the design of the AF sensor module 5. ΔL ′ can be obtained from the reference two-image interval (Lo) and the current two-image interval (Lt). The AF sensor 204 has a plurality of the above-described configurations so that focus detection can be performed at a plurality of positions on the photographing screen. The focus adjustment of the autofocus function uses a lens whose focus position is known in advance, and the two image intervals obtained from the AF sensor 204 so that the focus position comes to the position on the optical axis of the image sensor (image sensor assembling error). Are stored in the EEPROM as AF focus correction parameters.

(Inclusive relationship between exit pupil of imaging optical system and entrance pupil of focus detection optical system)
Next, the principle of vignetting of the light beam generated depending on the type of lens 100 attached to the digital camera 200 will be described with reference to FIG. FIG. 4 is a diagram for explaining the vignetting of the light beam used in the focus detection device caused by the difference in the position of the exit pupil of the photographing optical system.

  FIG. 4A shows a case where the photographing optical system is bright (F value is small), and the position of the exit pupil matches the position of the entrance pupil of the focus detection device. It shows that the light beam used by the focus detection device indicated by the ellipse is included in the light beam of the photographing optical system at the position of the entrance pupil indicated by the circle.

  In FIG. 4A, the circle indicates the restriction of the photographing optical system at the entrance pupil position of the focus detection device, and the pupil (two ellipses) indicates the light beam range used by the phase difference focus detection device. When the position of the exit pupil of the photographic optical system matches the position of the entrance pupil of the focus detection device, and the F value of the exit pupil of the photographic optical system is smaller than a predetermined F value specified by the focus detection device No vignetting occurs in the light beam used in the focus detection device. Therefore, detection of the focus adjustment state in the focus detection region in which the entrance pupil of the focus detection optical system is included in the exit pupil of the imaging optical system is allowed.

  However, when the position of the exit pupil of the photographing optical system does not match the position of the entrance pupil of the focus detection system, vignetting occurs in the light beam used in the focus detection device. That is, FIG. 4B shows that the position of the exit pupil of the photographing optical system and the position of the entrance pupil of the focus detection device do not coincide with each other, so that vignetting occurs in a trial light beam of the focus detection device. The circle in FIG. 4B indicates the light beam from the off-axis of the photographing optical system at the entrance pupil position of the focus detection device, and the two ellipses indicate the position of the light beam used by the focus detection device.

  In the state of FIG. 4B, vignetting occurs in one ellipse of the light flux used by the focus detection device, and the light amount of the focus detection line sensor is reduced. Therefore, detection of the focus adjustment state in the focus detection region where the entrance pupil of the focus detection optical system is not included in the exit pupil of the imaging optical system is limited.

  Further, although the entrance pupil of the focus detection device is specified at a predetermined position with a predetermined F value, even when the F value of the exit pupil of the photographing optical system is larger than the F value specified by the focus detection device, Vignetting occurs in the light beam used by the focus detection device. That is, FIG. 4C shows that vignetting occurs when the F value of the exit pupil of the photographing optical system is larger than the F value specified by the focus detection device. In FIG. 4C, a circle indicates the light beam from the optical axis of the photographing optical system at the entrance pupil position of the focus detection device, and two ellipses indicate the position of the light beam used by the focus detection device.

  In the state of FIG. 4C, vignetting occurs in the two ellipses, and the light amount decreases in the focus detection line sensor. Therefore, detection of the focus adjustment state in the focus detection region where the entrance pupil of the focus detection optical system is not included in the exit pupil of the imaging optical system is limited.

  As described above, the vignetting method of the light beam used in the focus detection device is different for each photographing lens, and accordingly, the light amount decrease on the focus detection line sensor is also different for each photographing lens.

(Auto focus detection mode types)
Next, the types of automatic focus detection modes provided by the automatic focus detection device will be described with reference to FIG. FIG. 5 is a diagram for explaining the types of automatic focus detection modes. FIG. 5A shows a configuration in the finder field that can be seen when looking through the finder. This figure shows a state where a plurality of segments (display portions) of the transmissive liquid crystal 251 are all points. For example, the remaining battery level, engraved lines indicating the autofocus detectable range in the finder, engraved lines indicating the grid shape may be displayed, or information other than the above may be displayed.

  In this proposal, four types of auto focus detection modes are provided in order from the largest selection region, namely, the whole region focus detection mode, the large zone focus detection mode, the zone focus detection mode, and the arbitrary single point focus detection mode. Will be described.

  The all-region focus detection mode is a mode in which focus detection is performed using a plurality of focus detection frames in a focus-detectable region. As the focus detection frames, a1 to a9, b1 to b9, c1 to c9, d1 to d9, and e1 to e9 are used. In addition, parentheses 310, 340, 332, and 342 are displayed in a form that represents the fully automatic focus detection mode.

  When the release SW 231 is pressed by the user and the system controller 223 executes the focus detection algorithm stored in the EEPROM 222, the focus detection circuit 205 performs focus detection. If the focus detection state is not in focus, the system controller 223 sends a signal to the lens control circuit 104 to drive the lens 101 in focus. When the lens is driven, the focus detection circuit 104 performs focus detection again to determine whether or not the focus detection state is in focus. When the focus detection state is in-focus, a focus detection frame (for example, b5) corresponding to the all-region focus detection mode is turned on to notify the photographer that the focus is achieved. The in-focus display mode can be set freely.

  Since the focus detection frame cannot be selected, when the system controller 223 executes the focus selection algorithm stored in the EEPROM 222 by operating the electronic dial 226, the operation of the electronic dial 226 is ignored. Alternatively, a warning display indicating that the operation is invalid is performed on the image display circuit 213.

  The large zone focus detection mode is a mode in which focus detection is performed using a plurality of focus detection frames in a focus detectable region. The large zone includes three regions: a large zone region 1 surrounded by parentheses 310 and 312, a large zone region 2 surrounded by parentheses 320 and 322, a parenthesis 330 and a large zone region 3 surrounded by parentheses 332. Consists of. The user selects a focus detection area from three areas. Hereinafter, a case where the large zone 1 is selected will be described. As the focus detection frames of the large zone region 1, a1 to a3, b1 to b3, c1 to c3, d1 to d3, and e1 to e3 are used. In addition, the parentheses 310 and 312 are turned on in the form of representing the large zone region 1 in the large zone detection mode.

  When the release SW 231 is pressed by the user and the system controller 223 executes the focus detection algorithm stored in the EEPROM 222, the focus detection frame (for example, b2) corresponding to the large zone 1 is turned on when the focus detection state is in focus. And inform the photographer that the subject is in focus.

  When the system controller 223 executes the focus selection algorithm stored in the EEPROM 222 by operating the electronic dial 226, the selected area can be moved. First, since the large zone 1 is selected, the parentheses 310 and 312 are lit. When the large zone 2 is selected by operating the electronic dial 226, the parentheses 320 and 322 are lit.

  The zone focus detection mode is a mode in which focus detection is performed using a plurality of focus detection frames in a focus detectable region. A zone is composed of a total of nine focus detection frames surrounded by three vertical and three horizontal regions as shown in FIGS. The user selects a total of nine focus detection frames surrounded by three vertical and three horizontal areas from all the areas. Hereinafter, a case where the central zone as shown in FIG. 6A is selected will be described. B4 to b6, c4 to c6, and d4 to d6 are used as focus detection frames in the central zone region. In addition, each of the nine focus detection frames is turned on in a form representing the zone area.

  When the release SW 231 is pressed by the user and the system controller 223 executes the focus detection algorithm stored in the EEPROM 222, when the focus detection state is in focus, the focus detection frame (for example, b5) corresponding to the zone is turned on. Inform the photographer that he is in focus.

  When the system controller 223 executes the focus selection algorithm stored in the EEPROM 222 by operating the electronic dial 226, the selected area can be moved. First, when the zone shown in FIG. 6A is selected and the selected area is moved upward, the light is turned on as shown in FIG. 6B. When the zone shown in FIG. 6A is selected and the selected area is moved to the left, it is lit as shown in FIG.

  The arbitrary one-point focus detection mode is a mode in which focus detection is performed using one focus detection frame in an area where focus detection is possible. The selected focus detection frame is lit to express one arbitrary point. Hereinafter, a case where c5 which is the central focus detection frame is selected will be described.

  When the release SW 231 is pressed by the user and the system controller 223 executes the focus detection algorithm stored in the EEPROM 222, when the focus detection state is in focus, the selected focus detection frame (for example, c5) is turned on, Inform the photographer that he is in focus.

  When the system controller 223 executes the focus selection algorithm stored in the EEPROM 222 by operating the electronic dial 226, the selected focus detection frame can be moved. First, when the focus detection frame selected upward is moved, b5 is lit. When the focus detection frame selected in the left direction is moved, c4 is lit.

  Next, a sequence for determining the type of the lens 100 attached to the digital camera 200 and changing the currently selected focus detection frame will be described with reference to FIGS.

  In the present embodiment, it is assumed that the vignetting of the luminous flux is measured in advance according to the type of the lens 100 and the focus detectable area is determined. For example, in a certain lens 100, FIG. 5A is a focus detectable region. However, in another lens 100, FIG. 5B is a focus detectable region. In the present embodiment, description will be made assuming that the lens having the focus detectable region in FIG. 5A is replaced with the lens having the focus detectable region in FIG. 5B.

  FIG. 7 is a flowchart of processing for determining the type of the lens 100 attached to the digital camera 200 in the first embodiment and changing the currently selected focus detection frame. Each process in this flowchart is realized by the system controller 223 executing a program stored in the EEPROM 222.

  When the menu SW 236 is pressed, a power control unit (not shown) is activated to start supplying power to the system controller 223. The system controller 223 starts execution from step S102 of FIG.

[Step S102] Determine the Lens ID The lens ID stored in the lens control circuit 104 is acquired.

[Step S104] Obtaining a Focus Detectable Area A focus detectable area corresponding to the lens ID stored in the EEPROM 223 is obtained from the lens ID obtained in step S102.

[Step S106] Determine vignetting of selected focus detection frame. It is determined whether or not vignetting has occurred in the focus detection available area acquired in step S104 in the currently selected focus detection frame.

[Step S108] Whether or not vignetting has been determined in step S106. If vignetting has occurred, the process proceeds to step S110. If vignetting has not occurred, the flowchart ends.

[Step S110] Measuring the minimum movement destination of the selected focus detection frame The minimum movement destination is measured so that the movement necessary for the selected focus detection frame to be within the focus detectable region by the new lens is the shortest.

[Step S112] Move the Selected Focus Detection Frame Move the selected focus detection frame to the minimum movement destination measured in step S110.

  Specific processing in step S106, step S110, and step S112 will be described with reference to FIGS. 5 (a) and 5 (b). When the whole-area focus detection mode is selected as the type of automatic focus detection mode, FIG. 5A is a focus-detectable area, so that the focus detection frames are a1 to a9, b1 to b9, and c1 to c9. , D1 to d9, and e1 to e9 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames a1 to a9 and e1 to e9 become focus detection frames that are not included in the focus detectable frame, and it is determined that there is vignetting. Thereafter, by moving the selected focus detection frame, b1 to b9, c1 to c9, and d1 to d9 are used as the focus detection frames.

  Further, when the large zone focus detection mode is selected as the type of the automatic focus detection mode, since FIG. 5A is a focus detectable region, the focus is selected when the left large zone region is selected. As detection frames, a1 to a3, b1 to b3, c1 to c3, d1 to d3, and e1 to e3 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames a1 to a3 and e1 to e3 become focus detection frames that are not included in the focus detectable frame, and it is determined that there is vignetting. Thereafter, by moving the selected focus detection frame, b1 to b3, c1 to c3, and d1 to d3 are used as the focus detection frames.

  Further, when the zone focus detection mode is selected as the type of the automatic focus detection mode, FIG. 5A is the focus detection possible region. Therefore, when the lower left zone is selected, the focus detection frame is c1. -C3, d1-d3, e1-e3 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames e1 to e3 become focus detection frames not included in the focus detectable frame, and it is determined that there is vignetting. Thereafter, by measuring the minimum movement destination, b1 to b3, c1 to c3, and d1 to d3 are used as the focus detection frames.

  Further, when the arbitrary single-point focus detection mode is selected as the type of the automatic focus detection mode, FIG. 5 (a) is the focus detectable region, and therefore e3 is selected as the focus detection frame. . When the lens is changed and FIG. 5B becomes the focus detectable region, e3 of the focus detection frame becomes a focus detection frame not included in the focus detectable frame, and it is determined that there is vignetting. Then, d3 is used as a focus detection frame by measuring the minimum movement destination.

  As described above, in changing the focus detection frame that is currently selected, the type of the lens 100 attached to the digital camera 200 is determined, and the focus is switched to the focus detectable region that is determined in advance for each lens. The vignetting of the detection frame is determined, the minimum movement destination is measured, and the selected focus detection frame is moved.

  As described above, by determining the area where focus detection is possible based on the characteristics of the focus detection light beam by the lens, lens attachment / detachment is detected, vignetting is determined, and the focus detection frame and the focus detection area transition It has become possible to make control easier and to make it easier to understand the transition of the focus detection mode for setting the focus detection frame and focus detection area.

[Example 2]
In the first embodiment, an area in which focus detection is possible is determined in advance based on the characteristics of the focus detection light beam by the lens, thereby detecting lens attachment / detachment, determining vignetting, and controlling transition of the focus detection frame and focus detection area. In addition, the apparatus configuration related to the method of changing the focus detection frame that makes it easy to understand the transition of the focus detection mode for setting the focus detection frame and the focus detection region has been described.

  In the second embodiment, an apparatus configuration relating to a method of changing the selected focus detection frame different from the first embodiment will be described.

  FIG. 8 is a flowchart of processing for determining the type of the lens 100 attached to the digital camera 200 in the second embodiment and changing the currently selected focus detection frame. Each process in this flowchart is realized by the system controller 223 executing a program stored in the EEPROM 222. Here, steps different from those in the first embodiment will be described.

[Step S114] The selected focus detection frame is moved to the center. The selected focus detection frame is moved to the center of the focus detection area in the currently selected focus detection mode. Specific processing in step S114 will be described with reference to FIGS. 5 (a) and 5 (b).

  When the whole-area focus detection mode is selected as the type of automatic focus detection mode, FIG. 5A is a focus-detectable area, so that the focus detection frames are a1 to a9, b1 to b9, and c1 to c9. , D1 to d9, and e1 to e9 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames a1 to a9 and e1 to e9 become focus detection frames that are not included in the focus detectable frame, and it is determined that there is vignetting. Since there is no region corresponding to the center of the focus-detectable region in the all-region focus detection mode, by subsequently moving the selected focus detection frame, b1 to b9, c1 to c9, and d1 to d9 are used as the focus detection frames. Will be used.

  Further, when the large zone focus detection mode is selected as the type of the automatic focus detection mode, since FIG. 5A is a focus detectable region, the focus is selected when the left large zone region is selected. As detection frames, a1 to a3, b1 to b3, c1 to c3, d1 to d3, and e1 to e3 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames a1 to a3 and e1 to e3 become focus detection frames that are not included in the focus detectable frame, and it is determined that there is vignetting. In the large zone focus detection mode, the area corresponding to the center of the focus detectable area is b4 to b6, c4 to c6, and d4 to d6 as the focus detection frames, and then the selected focus detection frame is moved. Thus, the focus detection frame is used.

  Further, when the zone focus detection mode is selected as the type of the automatic focus detection mode, FIG. 5A is the focus detection possible region. Therefore, when the lower left zone is selected, the focus detection frame is c1. -C3, d1-d3, e1-e3 are used. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frames e1 to e3 become focus detection frames not included in the focus detectable frame, and it is determined that there is vignetting. In the zone focus detection mode, the area corresponding to the center of the focus detectable area is b4 to b6, c4 to c6, and d4 to d6 as focus detection frames, and then the selected focus detection frame is moved. The focus detection frame is used.

  In addition, when the arbitrary single-point focus detection mode is selected as the type of the automatic focus detection mode, it is assumed that e3 is selected as the focus detection frame because FIG. When the lens is changed and FIG. 5B becomes the focus detectable region, the focus detection frame e3 becomes a focus detection frame not included in the focus detectable frame, and it is determined that there is vignetting. In the arbitrary one-point focus detection mode, the region corresponding to the center of the focus-detectable region is c5 as the focus detection frame, and then the focus detection frame is used by moving the selected focus detection frame. become.

  As described above, in changing the currently selected focus detection frame, the type of lens attached to the digital camera is determined, and after switching to a focus detectable area predetermined for each lens, the selected focus detection frame is selected. Vignetting is determined, and the selected focus detection frame is moved to the center of the focus detection region in the currently selected focus detection mode.

  As described above, similarly to the first embodiment, by determining a region where focus detection is possible in advance based on the characteristics of the focus detection light beam by the lens, lens attachment / detachment is detected, vignetting is determined, a focus detection frame, It is possible to control the transition of the focus detection area, and to make the transition of the focus detection mode for setting the focus detection frame and the focus detection area easy to understand.

[Example 3]
In the first and second embodiments, an area where focus detection is possible is determined in advance based on the characteristics of the focus detection light beam by the lens, thereby detecting lens attachment / detachment, determining vignetting, and detecting the focus detection frame and the focus detection area. The apparatus configuration related to the method for changing the focus detection frame that enables the transition control to be performed and further facilitates the transition of the focus detection mode for setting the focus detection frame and the focus detection area has been described.

  In the first and second embodiments, the description has been made on the assumption that the automatic focus detection mode does not change when lens attachment / detachment is detected and vignetting is determined. However, in reality, there is an upper limit on the number of characters such as lines and frames that can be displayed on the transmissive liquid crystal due to cost restrictions, and the focus detection area and focus detection frame may not be sufficiently expressed.

  Therefore, in the third embodiment, when the large zone detection mode that is the automatic focus detection mode cannot be expressed when FIG. 5B is the focus detectable region, the selected focus detection frame different from the first and second embodiments. An apparatus configuration relating to the changing method will be described.

  FIG. 9 shows the configuration in the viewfinder field that is visible when looking through the viewfinder when the large zone detection mode, which is the automatic focus detection mode, cannot be expressed with respect to FIG. This figure shows a state where a plurality of segments (display portions) of the transmissive liquid crystal 251 are all points.

  In FIG. 5 (b), the large zone is surrounded by parentheses 310 and 312, a large zone region 1 surrounded by parentheses 320 and 320, a large zone region 2 surrounded by parentheses 322, a parenthesis 330 and a large region surrounded by parentheses 332. Although three areas of the zone area 3 can be expressed, in FIG. 9, there are no parentheses 352, 360, 362, and 370 for expressing the large zone area.

  In the liquid crystal display of FIG. 5A, all the automatic focus detection modes of the all-region focus detection mode, the large zone focus detection mode, the zone focus detection mode, and the arbitrary one-point focus detection mode can be selected. On the other hand, in the liquid crystal display of FIG. 9, an auto focus detection mode of an all-region focus detection mode, a zone focus detection mode, or an arbitrary one-point focus detection mode can be selected.

  Here, when all the auto focus detection modes are selectable and the focus detection area is the widest in FIG. 5A, the size of the focus detection area that can be taken for each auto focus detection mode is compared. In this order, the entire area focus detection mode, the large zone focus detection mode, the zone focus detection mode, and the arbitrary single point focus detection mode are selected. If the automatic focus detection mode is automatically switched in the direction in which the focus detection area is reduced, it is considered that there is less sense of discomfort if the automatic focus detection mode is switched to the auto focus detection mode with a small difference in focus detection areas. That is, when the large zone focus detection mode cannot be selected in the automatic focus detection mode in FIG. 9, it is only necessary to switch to the zone focus detection mode.

  FIG. 10 is a flowchart of processing for determining the type of the lens 100 attached to the digital camera 200 and changing the currently selected focus detection frame in the third embodiment. Each process in this flowchart is realized by the system controller 223 executing a program stored in the EEPROM 222.

  Here, steps different from those in the first embodiment will be described. Here, when the large zone focus detection mode is selected as the automatic focus selection mode in FIG. 5A, the focus detectable area is changed in FIG. 9, and the large zone detection mode which is the automatic focus detection mode cannot be expressed. Will be described.

[Step S120] It is determined whether there is a change in the automatic focus detection mode. It is determined whether there is a change in the automatic focus detection mode. In FIG. 9, since the large zone focus detection mode cannot be selected as the auto focus selection mode, the auto focus detection mode is changed.

[Step S122] Whether there is a change In step S120, it is determined whether there is a change in the automatic focus detection mode. If there is a change, the process branches to step S124, and if there is no change, the process branches to step S114.

[Step S124] Changing the automatic focus detection mode The automatic focus detection mode is changed. When the large zone focus detection mode cannot be selected in the automatic focus detection mode in FIG. 9, the mode is switched to the zone focus detection mode.

[Step S114] The selected focus detection frame is moved to the center. The selected focus detection frame is moved to the center of the focus detection area in the currently selected focus detection mode.

  When the large zone focus detection mode cannot be selected in the automatic focus detection mode in FIG. 9, the zone focus detection mode is switched, so that the region corresponding to the center of the focus detectable region, that is, b4 to b6, The selected focus detection frame is moved to c4 to c6 and d4 to d6.

  In this way, in changing the focus detection frame that is currently selected, the type of lens attached to the digital camera is determined, and after switching to a focus detectable region that is determined in advance for each lens, the automatic focus detection mode The automatic focus detection mode is changed and the selected focus detection frame is moved to the center of the focus detection area in the currently selected focus detection mode.

  As described above, as in the first and second embodiments, by setting a focus-detectable region in advance based on the characteristics of the focus detection light beam by the lens, it is possible to detect lens detachment, determine vignetting, and detect focus. It is possible to perform transition control of the frame and the focus detection area, and to make it easy to understand the transition of the focus detection mode for setting the focus detection frame and the focus detection area.

100 photographic lens unit, 101 photographic lens, 102 aperture,
103 lens drive mechanism, 104 lens control circuit, 105 aperture drive mechanism,
106 Aperture control circuit, 107 Electrical contact group, 200 Digital camera,
201 Penta prism, 202 Quick return mirror, 203 Sub mirror,
204 AF sensor, 206 eyepiece, 207 photometry circuit,
208 focal plane shutter, 209 filter, 210 image sensor,
211 shutter charge mirror drive mechanism, 212 shutter control circuit,
213 image display circuit, 214 encoder circuit, 215 D / A converter,
216 A / D converter, 217 timing pulse generation circuit,
218 image data recording medium, 219 image compression circuit,
220 image data controller, 221 DRAM, 222 EEPROM,
223 system controller, 224 communication interface circuit,
225 Display circuit, 226 Electronic dial SW, 227 Determination SW,
229 Mode setting SW, 230 Release SW2, 231 Release SW1,
236 Menu SW, 237 Playback SW, 238 Enlargement / reduction SW, 250 Focus version,
251 Transmission type liquid crystal, 300 External control device

Claims (4)

Focus detection optics for forming images of light beams that have passed through different areas of the exit pupil of the imaging optical system, using a phase difference type digital camera (200) capable of detecting the focus adjustment state of the imaging optical system in a plurality of focus detection areas. System, an AF sensor (204) that receives a light beam from the focus detection optical system, and a control means (223) that performs calculation related to the focus adjustment state of the photographing optical system based on the output of the AF sensor (204). The control means (223) determines the pattern of the focus detection area in which the entrance pupil of the focus detection optical system is included in the exit pupil of the imaging optical system, the F value of the imaging optical system, and the exit of the imaging optical system. A pattern storage means (223) for storing information according to information relating to the pupil position is provided, and the control means (223) provides information relating to the F value of the photographing optical system and the exit pupil position of the photographing optical system. Based on, characterized by a choice of a specific pattern that is stored, to permit detection of the focusing state at the focus detection area corresponding to the outer particular pattern that the pattern storage unit (223),
A focus detection mode determination means (223) for determining a focus detection mode selectable in the focus detection area, a focus detection mode selection means (223) for selecting a focus detection mode,
Focus detection position determination means (223) for determining a focus detection position designated in the selected focus detection mode;
Vignetting determination means (223) for determining whether the focus detection position is included in the focus detection area when the focus detection area changes,
A digital camera that changes a focus detection position when it is determined that vignetting has occurred. 2. The digital camera according to claim 1, wherein the detection device makes a transition so that the movement of the focus detection position is minimized when it is determined that vignetting has occurred. 2. The digital camera according to claim 1, wherein, when it is determined that vignetting has occurred in the detection device, the focus detection position is shifted to the center of an area selectable in the focus detection mode. The detection apparatus further includes a focus detection mode change determination unit that determines a change in the focus detection mode,
When it is determined by the focus detection mode change determination means that there is a change in the focus detection mode when the vignetting determination means determines that vignetting has occurred, the focus detection mode selection means changes the change. The digital camera according to claim 1, wherein the focus detection position is shifted to the center of an area selectable in the focus detection mode.