JP2008035243A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device which can appropriately photograph flash pictures with a simple arrangement. <P>SOLUTION: A front of a camera body 12 mounts two flashes 16A and 16B whose irradiation distances are different from each other. Upon flash photographing, AF processing is performed by changing an AF fill light step by step, and an appropriate flash for photographing is used according to a light emitting amount of the AF fill light when it is focused. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus that performs AF (Auto Focus) control of a photographic lens based on contrast information of an image obtained from an imaging element such as a CCD.

In general, a high-performance camera such as a single-lens reflex camera is provided with a distance measuring sensor for AF, and the distance to the subject (subject distance) is detected by the distance measuring sensor to perform AF control of the photographing lens. Done. At the time of flash shooting, the flash emission amount is determined based on the subject distance detected by the distance measuring sensor, and appropriate shooting is performed according to the scene (for example, Patent Documents 1 and 2).
JP-A-2005-316128 JP 2005-192139 A

  However, a compact camera with a simple configuration does not include a distance measuring sensor like a single-lens reflex camera, and AF control is performed based on contrast information of an image obtained from an image sensor such as a CCD ( So-called contrast AF). For this reason, there is a drawback in that an accurate subject distance cannot be detected and appropriate flash photography cannot be performed.

  In addition, in the case of a compact camera, since it is difficult to control the amount of emitted light with respect to the flash function, if the distance to the subject is long, there is also a drawback that appropriate shooting cannot be performed because the flash light does not reach.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an imaging apparatus capable of appropriate flash photography with a simple configuration.

  According to a first aspect of the present invention, in order to achieve the above object, in the imaging apparatus that captures an image of a subject with an imaging unit via a photographic lens, the imaging is performed based on an image obtained from the imaging unit before actual imaging. AF control means for performing AF processing of the lens, a plurality of flash light emitting means having different irradiation distances, AF auxiliary light emitting means for emitting AF auxiliary light toward the subject, and the AF auxiliary light based on the result of the AF processing AF auxiliary light emission control means for controlling the emission of AF auxiliary light by the light emitting means, wherein AF auxiliary light emission control is performed to increase the amount of light emission stepwise and to emit AF auxiliary light from the AF auxiliary light emission means when an AF error occurs. And a setting means for setting a flash light emitting means to be used for actual photographing from among the plurality of flash light emitting means. Setting means for setting flash light emission means used for actual photographing in accordance with the amount of emitted AF auxiliary light, and flash light emission control means for controlling flash light emission by the plurality of flash light emission means, wherein the setting means And a flash light emission control means for emitting a flash from the flash light emission means set in (1).

  According to the first aspect of the present invention, the plurality of flash light emitting means having different irradiation distances are provided, and the flash light emitting means used during the main photographing is determined according to the light emission amount of the AF auxiliary light at the time of focusing. That is, since it can be estimated that the subject is farther away as the AF auxiliary light emission amount at the time of focusing is larger, the flash light emitting means having a longer irradiation distance as the AF auxiliary light emission amount at the time of focusing is used. Take a picture. Thereby, appropriate flash photography can be performed without performing complicated control with a simple configuration.

  According to a second aspect of the present invention, in order to achieve the object, an image obtained from the display unit, an irradiation range calculation unit that calculates an irradiation range of the flash light emitting unit used for actual photographing, and an image obtained from the imaging unit The image pickup apparatus according to claim 1, further comprising: a display control unit configured to display the display unit on the display unit and to display a frame indicating the irradiation range on the display unit.

  According to the invention which concerns on Claim 2, the display means is provided, The frame which shows the irradiation range of a flash with the image obtained from an imaging means is displayed on the display means. Thereby, the photographer can appropriately recognize the flash irradiation range, and can perform appropriate flash photography.

  In order to achieve the above object, the invention according to claim 3 includes a shooting condition determining unit that determines shooting conditions at the time of the main shooting based on an image obtained from the imaging unit before the main shooting. When there is a flash light emitting unit having a longer irradiation distance than the set flash light emitting unit, the flash light emission control unit pre-flashes the flash light emitting unit having an irradiation distance longer than the flash light emitting unit set by the setting unit. 3. The photographing condition determining unit according to claim 1 or 2, wherein the photographing condition determining unit determines a photographing condition at the time of actual photographing based on an image obtained from the imaging unit when the flash light emitting unit is pre-flashed. An imaging device is provided.

  According to the third aspect of the present invention, when there is a flash light emitting unit having a longer irradiation distance than the flash light emitting unit used at the time of actual photographing, the flash light emitting unit is pre-lighted to determine the photographing condition at the time of the main photographing. Thus, more appropriate flash photography can be performed.

  According to a fourth aspect of the present invention, in order to achieve the above object, when there is no flash light emitting means having an irradiation distance longer than that of the flash light emitting means set by the setting means, the photographing condition determining means has a prescribed shutter speed. The imaging apparatus according to claim 3, wherein the imaging conditions at the time of actual imaging are determined as described above.

  According to the fourth aspect of the present invention, when there is no flash light emitting unit whose irradiation distance is longer than the flash light emitting unit used at the time of main photographing, the photographing condition at the time of main photographing is determined so as to be equal to or higher than the prescribed shutter speed. . As a result, image blur due to camera shake can be prevented, and appropriate flash photography can be performed.

  According to the imaging apparatus of the present invention, appropriate flash photography can be performed with a simple configuration.

  The best mode for carrying out an imaging apparatus according to the present invention will be described below with reference to the accompanying drawings.

  1 and 2 are a front perspective view and a rear perspective view, respectively, showing the external configuration of a digital camera to which the present invention is applied.

  As shown in the figure, the digital camera 10 is configured as a so-called compact camera, and the camera body 12 is formed in a shape that can be held with one hand.

  As shown in FIG. 1, a photographing lens 14, a first flash 16A, a second flash 16B, a speaker 18, an AF auxiliary light lamp 20, and the like are provided on the front surface of the camera body 12, and a shutter button is provided on the upper surface. 22, a mode lever 24, a power button 26 and the like are provided.

  On the other hand, as shown in FIG. 2, a monitor 28, a zoom button 30, a playback button 32, a function button 34, a cross button 36, a MENU / OK button 38, a DISP / BACK button 40, etc. are provided on the back of the camera body 12. It has been.

  Although not shown, a tripod screw hole and an openable / closable battery cover are provided on the bottom surface of the camera body 12, and a battery storage chamber and a memory card for storing the battery are provided inside the battery cover. Is provided with a memory card slot.

  The photographic lens 14 is constituted by a retractable zoom lens, and is extended from the camera body 12 when the digital camera 10 is turned on. Since the zoom mechanism and the retracting mechanism of the photographic lens 14 are well-known techniques, a description of their specific configuration is omitted here.

  The first flash 16A and the second flash 16B are arranged in parallel on the upper part of the photographing lens 14, and emit light as needed during photographing. The first flash 16A and the second flash 16B are composed of flashes having different irradiation angles and irradiation distances. That is, as shown in FIG. 3A, the first flash 16A is composed of a flash having a wide irradiation angle and a short irradiation distance, and the second flash 16B is formed as shown in FIG. 3B. The flash has a narrow irradiation angle and a long irradiation distance. Therefore, by using the second flash 16B for a distant subject, appropriate flash photography can be performed.

  The first flash 16 </ b> A is configured with an irradiation angle that can cover the wide end of the photographic lens 14, and is configured to be usable in the entire zoom range of the photographic lens 14.

  The AF auxiliary light lamp 20 is composed of, for example, a high-intensity LED, and emits light as necessary during AF. The AF auxiliary light lamp 20 is configured to change the amount of AF auxiliary light to be emitted.

  The shutter button 22 is constituted by a two-stage stroke type switch composed of so-called “half press” and “full press”. When the shutter release button 22 is half-pressed, the digital camera 10 performs shooting preparation processing, that is, each of AE (Automatic Exposure), AF (Auto Focus), and AWB (Automatic White Balance). When the image is processed and fully pressed, the image is captured and recorded.

  The mode lever 24 is used for setting the shooting mode. The mode lever 24 is provided so as to be swingable around the shutter button 22 within a predetermined angle range, and can be set to “SP position”, “AUTO position”, “M position”, and “moving picture position”. Is provided. The digital camera 10 is set to the “scene program shooting mode” by setting the mode lever 24 to the “SP position”, and is set to a mode for performing exposure control and shooting control according to the shooting scene. Also, by setting the “AUTO position”, the “auto shooting mode” is set, and the mode is set to perform the exposure control fully automatically. Also, by setting the “M position”, the “manual shooting mode” is set, and the exposure setting is manually set. Also, by setting the “moving image position”, the “moving image shooting mode” is set, and the moving image shooting mode is set. As the “scene program shooting mode”, for example, “portrait mode” for shooting a person, “landscape mode” for shooting a landscape, “sport mode” for shooting a sport, “night view mode” for shooting a night scene, “Underwater mode” for shooting is prepared.

  The power button 26 is used to turn on / off the power of the digital camera 10, and is turned on / off when pressed for a predetermined time (for example, 2 seconds).

  The monitor 28 is composed of a color LCD. The monitor 28 is used as an image display unit for displaying captured images, and is used as a GUI during various settings. Further, at the time of shooting, an image captured by the image sensor is displayed through and used as an electronic viewfinder.

  The zoom button 30 is used for a zoom operation of the photographic lens 14 and includes a zoom tele button for instructing zooming to the telephoto side and a zoom wide button for instructing zooming to the wide angle side.

  The playback button 32 is used for an instruction to switch to the playback mode. That is, the digital camera 10 is switched to the playback mode when the playback button 32 is pressed during shooting. When the playback button 32 is pressed while the power is off, the digital camera 10 is activated in the playback mode.

  The function button 34 is used to call up various setting screens for shooting and playback functions. That is, when the function button 34 is pressed during photographing, a setting screen for image size (number of recording pixels), sensitivity, etc. is displayed on the monitor 28. When the function button 4 is pressed during reproduction, printing is performed on the monitor 28. A reservation (DPOF) setting screen is displayed.

  The cross button 36 is provided so that it can be pressed in four directions, up, down, left, and right, and a function corresponding to the setting state of the camera is assigned to the button in each direction. For example, at the time of shooting, a function for switching the macro function ON / OFF is assigned to the left button, and a function for switching the flash mode is assigned to the right button. In addition, a function for changing the brightness of the monitor 28 is assigned to the upper button, and a function for switching ON / OFF of the self-timer is assigned to the lower button. Further, during playback, a frame advance function is assigned to the left button, and a frame return function is assigned to the right button. Also, a function for changing the brightness of the monitor 28 is assigned to the upper button, and a function for deleting the image being reproduced is assigned to the lower button. In various settings, a function for moving the cursor displayed on the monitor 28 in the direction of each button is assigned.

  The MENU / OK button 38 is used to call a menu screen (MENU function), and is used to confirm selection contents, execute a process, etc. (OK function), and is assigned according to the setting state of the digital camera 10. Is switched.

  The DISP / BACK button 40 is used for a display content switching instruction (DISP function) of the monitor 28 and an instruction for canceling an input operation (BACK function), and is assigned according to the setting state of the digital camera 10. The function is switched.

  FIG. 4 is a block diagram showing an electrical configuration of the digital camera 10 of the present embodiment.

  As shown in the figure, the digital camera 10 includes a CPU 110, an operation unit (shutter button 22, mode lever 24, power button 26, zoom button 30, playback button 32, function button 34, cross button 36, MENU / OK button 38. , DISP / BACK button 40, etc.) 112, ROM 114, RAM 116, EEPROM 118, VRAM 120, imaging optical system 124, imaging optical system drive control unit 126, image sensor 128, timing generator 130, analog signal processing unit 132, A / D converter 134 , Image input controller 136, image signal processor 138, compression / decompression processor 140, media controller 144, memory card 146, display controller 148, AE / AWB detector 152, AF detector 154, flash controller 15 , And a AF assist lamp control unit 158 and the like.

  The CPU 110 functions as a control unit that performs overall control of the entire operation of the digital camera 10 and also functions as a calculation unit that performs various types of calculation processing. Control each part.

  The ROM 114 stores a control program executed by the CPU 110 and various data necessary for control, and the EEPROM 118 stores various setting information such as user setting information.

  The RAM 116 is used as a work area for the CPU 110 and is used as a temporary storage area for image data, and the VRAM 120 is used as a temporary storage area dedicated for display image data.

  The photographic optical system 124 includes a photographic lens 14, a diaphragm, and a shutter, and each component operates by being driven by a drive unit 124A configured by an actuator such as a motor. For example, the focus lens group constituting the photographing lens 14 is driven by the focus motor to move in the front-rear direction, and the zoom lens group is driven by the zoom motor to move in the front-rear direction. The diaphragm is driven by a diaphragm motor to expand and contract, and the shutter is driven by a shutter motor to open and close.

  The photographing optical system drive control unit 126 controls the driving unit 124A of the photographing optical system 124 in accordance with a command from the CPU 110, and controls the operations of the photographing lens 14, the diaphragm, and the shutter.

  The image pickup device 128 is constituted by, for example, a color CCD having a predetermined color filter array, and electronically picks up an image of a subject imaged by the photographing optical system 124. A timing generator (TG) 130 outputs a timing signal for driving the image sensor 128 in response to a command from the CPU 110.

  The analog signal processing unit 132 is for the purpose of reducing correlated double sampling processing (noise (particularly thermal noise) included in the output signal of the image sensor) and the like for the image signal output from the image sensor 128. The process of obtaining accurate pixel data by taking the difference between the feed-through component level and the pixel signal component level included in the output signal for each pixel is amplified, and output.

  The A / D converter 134 converts the R, G, and B analog image signals output from the analog signal processing unit 132 into digital image signals.

  The image input controller 136 has a built-in line buffer with a predetermined capacity, accumulates image signals for one image output from the A / D converter 134 in accordance with instructions from the CPU 110, and stores them in the RAM 116.

  The image signal processing unit 138 includes a synchronization circuit (a processing circuit that interpolates a spatial shift of the color signal associated with the color filter array of the single CCD and converts the color signal into a simultaneous expression), a white balance correction circuit, and a gamma correction. Circuit, contour correction circuit, luminance / color difference signal generation circuit, etc., and according to a command from the CPU 110, the input image signal is subjected to necessary signal processing to obtain luminance data (Y data) and color difference data (Cr, Cb data). ) Is generated.

  The compression / decompression processing unit 140 performs compression processing in a predetermined format on the input image data in accordance with a command from the CPU 110 to generate compressed image data. Further, in accordance with a command from the CPU 110, the input compressed image data is subjected to a decompression process in a predetermined format to generate uncompressed image data.

  The media controller 144 controls reading / writing of data with respect to the memory card 146 loaded in the media slot in accordance with a command from the CPU 110.

  The display control unit 148 controls display on the monitor 28 in accordance with a command from the CPU 110. That is, in accordance with a command from the CPU 110, the input image signal is converted into a video signal (for example, NTSC signal, PAL signal, SCAM signal) for display on the monitor 28 and output to the monitor 28. The graphic information is output to the monitor 28.

  The AE / AWB detection unit 152 calculates a physical quantity necessary for AE control and AWB control from the input image signal in accordance with a command from the CPU 110. For example, as a physical quantity required for AE control, one screen is divided into a plurality of areas (for example, 16 × 16), and an integrated value of R, G, and B image signals is calculated for each divided area. The CPU 110 detects the brightness of the subject (subject brightness) based on the integrated value obtained from the AE / AWB detector 152, and calculates an exposure value (shooting EV value) suitable for shooting. Then, an aperture value and a shutter speed are determined from the calculated shooting EV value and a predetermined program diagram. Further, as a physical quantity necessary for AWB control, one screen is divided into a plurality of areas (for example, 16 × 16), and an average integrated value for each color of R, G, and B image signals is calculated for each divided area. . The CPU 110 obtains the ratio of R / G and B / G for each divided area from the obtained R accumulated value, B accumulated value, and G accumulated value, and R of the obtained R / G and B / G values. The light source type is discriminated based on the distribution in the / G, B / G color space. Then, according to the white balance adjustment value suitable for the determined light source type, for example, the value of each ratio is approximately 1 (that is, the RGB integration ratio is R: G: B≈1: 1: 1 in one screen). Then, a gain value (white balance correction value) for the R, G, and B signals of the white balance adjustment circuit is determined.

  The AF detection unit 154 calculates a physical quantity necessary for AF control from the input image signal in accordance with a command from the CPU 110. In the digital camera 10 according to the present embodiment, AF control is performed based on the contrast of the image obtained from the image sensor 128 (so-called contrast AF), and the AF detection unit 154 has a focus indicating the sharpness of the image from the input image signal. An evaluation value is calculated. The CPU 110 detects a position where the focus evaluation value calculated by the AF detection unit 154 is maximized, and moves the focus lens group to that position. That is, the focus lens group is moved from the closest distance to infinity in a predetermined step, the focus evaluation value is obtained at each position, and the position where the obtained focus evaluation value is the maximum is set as the in-focus position, and the focus lens group is at that position. Move.

  The flash controller 156 individually controls the light emission of the first flash 16A and the second flash 16B in accordance with a command from the CPU 110.

  The AF auxiliary light lamp control unit 158 controls the light emission of the AF auxiliary light lamp 20 in accordance with a command from the CPU 110. That is, if the CPU 110 determines that the subject is dark during AF or determines that the subject has a low contrast, the CPU 110 causes the AF auxiliary light lamp 20 to emit light via the AF auxiliary light lamp control unit 158 and emits AF auxiliary light to the subject. Irradiate and execute AF control.

  At this time, the CPU 110 changes the amount of AF auxiliary light emitted from the AF auxiliary light lamp 20 as necessary. That is, when AF auxiliary light is emitted with a preset initial light emission amount and focusing cannot be performed (in the case of an AF error), the CPU 110 increases the light emission amount of the AF auxiliary light by a predetermined amount and executes AF control again. If an AF error occurs even with the light emission amount, the light emission amount of AF auxiliary light is increased by a predetermined amount, and AF control is executed again. As described above, when an AF error occurs, the CPU 110 executes AF control by increasing the light emission amount of the AF auxiliary light step by step in a preset step (executed up to the limit of the light emission amount of the AF auxiliary light).

  The operation of the digital camera 10 of the present embodiment configured as described above is as follows.

  As described above, the digital camera 10 according to the present embodiment is equipped with two flashes. Since the two flashes 16A and 16B have different irradiation distances, they are selectively used according to the subject distance. That is, for a subject at a subject distance that can be illuminated with the first flash 16A, flash photography is performed using the first flash 16A, and for a subject at a subject distance that cannot be illuminated with the first flash 16A. Then, flash photography is performed using the second flash 16B.

  As described above, the first flash 16A and the second flash 16B are selectively used according to the subject distance. However, in the digital camera 10 of the present embodiment, the subject distance that is the reference for the proper use is determined based on the amount of AF auxiliary light emitted. Infer. That is, as described above, in the digital camera 10 of the present embodiment, when an AF error occurs, the AF control is executed by gradually increasing the light emission amount of the AF auxiliary light, but this AF auxiliary light is far away. A subject requires a larger amount of light emission. Therefore, the subject distance can be estimated from the light emission amount of the AF auxiliary light.

  In the digital camera 10 of the present embodiment, the two flashes 16A and 16B are selectively used based on the subject distance estimated from the light emission amount of the AF auxiliary light.

  FIG. 5 is a flowchart showing a processing procedure at the time of flash photographing in the digital camera of the present embodiment.

  When the camera mode is set to the shooting mode (step S11), the CPU 110 executes through image display processing according to a predetermined control program (step S12). That is, an image obtained from the image sensor 128 via the photographing lens 14 is displayed on the monitor 28 as a through display. The photographer adjusts the angle of view by operating the zoom button 30 while viewing the image (through image) displayed through on the monitor 28. Then, the shutter button 22 is half-pressed to give an AF instruction.

  Based on the input from the operation unit 112, the CPU 110 determines whether or not the shutter button 22 is half-pressed (step S13). If it is determined that the shutter button 22 is half-pressed, AF processing is executed according to a predetermined control program (step S14). At this time, the CPU 110 emits AF auxiliary light from the AF auxiliary light lamp 20 with a preset initial light emission amount, and executes AF processing.

  From the result of the AF process, the CPU 110 determines whether or not AF is successful (step S15). That is, it is determined whether or not the subject can be focused.

  If it is determined that the AF has failed (AF error), the CPU 110 determines whether or not the light emission amount of the AF auxiliary light has reached a limit value (step S16). When determining that the light emission amount of the AF auxiliary light has not reached the limit value, the CPU 110 increases the light emission amount of the AF auxiliary light by one step (step S17), and again under the new light emission amount of the AF auxiliary light. AF processing is executed (step S14).

  Thereafter, the CPU 110 again determines the success or failure of the AF from the result of the AF process, and determines whether or not the subject is in focus (step S15).

  As described above, when an AF error occurs, the AF processing is executed by increasing the light emission amount of the AF auxiliary light step by step. If it is determined that AF has succeeded (focused), the CPU 110 determines a flash to be used based on the amount of AF auxiliary light emitted at the time of focusing (step S18). That is, the light emission amount of the AF auxiliary light at the time of focusing is compared with a preset threshold value, and if it is less than the threshold value, the first flash 16A is set as a flash used at the time of actual photographing. On the other hand, if the amount of AF auxiliary light emitted at the time of in-focus is equal to or greater than the threshold, the second flash 16B is set as a flash to be used during the main photographing.

  Thereafter, the CPU 110 performs a process for determining exposure conditions (sensitivity, aperture, shutter speed) according to a predetermined control program (step S19). Then, based on the input from the operation unit 112, it is determined whether or not the shutter button 22 is half-pressed (step S20). If it is determined that the half-press is released, the process returns to step S13 and the half-press is again determined. Determine.

  On the other hand, when determining that the half-press of the shutter button 22 has not been released, the CPU 110 determines whether or not the shutter button 22 is fully pressed based on an input from the operation unit 112 (step S21), and the shutter button 22 is fully pressed. If it is determined that the button has been pressed, the main photographing / recording process is executed (step S22).

  That is, the determined flash is emitted, the image sensor 128 is exposed with the determined aperture value and shutter speed, and a recording image is captured. An image signal output from the image sensor 128 by this imaging is taken into the image input controller 136 via the analog signal processing unit 132 and the A / D converter 134 and stored in the RAM 116. The image signal stored in the RAM 116 is added to the image signal processing unit 138 under the control of the CPU 110, and converted into image data (YUV data) including luminance data and color difference data. This image data is temporarily stored in the RAM 116 and then added to the compression / decompression processing unit 140. The compression / decompression processing unit 140 performs a predetermined compression process and then stores it in the RAM 116. The CPU 110 records the compressed image data stored in the RAM 116 as a still image file (eg, Exif) in a predetermined format on the memory card 146 via the media controller 144, and ends the process.

  As described above, when the AF auxiliary light fails, if the AF fails, the light emission amount is increased stepwise. However, if the AF fails even when the light emission amount reaches the limit value, that is, AF auxiliary light in step S16. When it is determined that the amount of emitted light has reached the limit value, the CPU 110 performs a predetermined error warning process (for example, displaying an error message on the monitor 28, generating a warning sound, etc.) (step S23), The process ends.

  As described above, in the digital camera 10 of the present embodiment, the subject distance is estimated from the light emission amount of the AF auxiliary light, and the two mounted flashes 16A and 16B are used properly. This makes it possible to perform flash photography by appropriately using the flash without separately installing a subject distance measuring means, and the overall configuration can be simplified.

  In addition, by using two flashes 16A and 16B having different irradiation distances, appropriate flash photography can be performed without using a complicated mechanism such as a zoom mechanism for the flash, and the entire configuration is simplified. be able to.

  In the above embodiment, the flash to be used for the main photographing is determined according to the light emission amount of the AF auxiliary light. However, the light emission amount may be adjusted at the same time. That is, even when the same flash is used, the light emission amount may be changed according to the light emission amount of the AF auxiliary light.

  In the above embodiment, the flash to be used for the main photographing is determined from the amount of AF auxiliary light emitted after focusing. However, the flash to be used for the main photographing is interlocked with the switching of the AF auxiliary light emission amount. You may switch.

  FIG. 6 is a flowchart showing a processing procedure when shooting is performed by switching the flash in conjunction with switching of the light emission amount of the AF auxiliary light.

  When the camera mode is set to the shooting mode (step S31), the CPU 110 executes through image display processing according to a predetermined control program (step S32). The photographer adjusts the angle of view by operating the zoom button 30 while viewing the through image displayed on the monitor 28. Then, the shutter button 22 is half-pressed to give an AF instruction.

  The CPU 110 determines whether or not the shutter button 22 is half-pressed based on the input from the operation unit 112 (step S33). If it is determined that the shutter button 22 is half-pressed, AF processing is executed according to a predetermined control program (step S34). At this time, the CPU 110 emits AF auxiliary light from the AF auxiliary light lamp 20 with a preset initial light emission amount, and executes AF processing.

  From the result of the AF process, the CPU 110 determines whether or not AF is successful (step S35). That is, it is determined whether or not the subject can be focused.

  Here, if it is determined that AF has succeeded, that is, it is in focus, the CPU 110 sets the first flash 16A as a flash to be used at the time of actual photographing (step S45).

  On the other hand, when determining that the AF has failed, the CPU 110 determines whether or not the light emission amount of the AF auxiliary light has reached a limit value (step S36). When determining that the light emission amount of the AF auxiliary light has not reached the limit value, the CPU 110 increases the light emission amount of the AF auxiliary light by one level (step S37), and again under the new light emission amount of the AF auxiliary light. AF processing is executed (step S38).

  Thereafter, the CPU 110 again determines the success or failure of the AF from the result of the AF process, and determines whether or not the subject is in focus (step S39).

  As described above, when an AF error occurs, the AF processing is executed by increasing the light emission amount of the AF auxiliary light step by step. If it is determined that AF has succeeded, that is, it is in focus, the CPU 110 sets the second flash 16B as a flash to be used at the time of actual photographing (step S40).

  Thereafter, the CPU 110 performs an exposure condition determination process according to a predetermined control program (step S41). Then, based on the input from the operation unit 112, it is determined whether the half-press of the shutter button 22 has been released (step S42). If it is determined that the half-press has been released, the process returns to step S33 to check whether the half-press has been released again. Determine.

  On the other hand, when determining that the half-press of the shutter button 22 has not been released, the CPU 110 determines whether or not the shutter button 22 is fully pressed based on an input from the operation unit 112 (step S43). If it is determined that the button has been pressed, the main photographing / recording process is executed (step S44).

  If it is determined in step S36 that the light emission amount of the AF auxiliary light has reached the limit value, the CPU 110 performs a predetermined error warning process (step S46) and ends the process.

  In this way, the flash to be used may be switched in conjunction with the switching of the light emission amount of the AF auxiliary light.

  It should be noted that the number of AF auxiliary light emission amounts can be changed at least by the number of flashes mounted on the camera minus one. Therefore, in the case of the above example, since two flashes are mounted, the light emission amount of the AF auxiliary light is switched at least one step. Similarly, when three flashes are mounted, at least two stages can be switched, and when four flashes are mounted, at least three stages can be switched.

  As described above, in the digital camera according to the present embodiment, the subject distance is estimated from the light emission amount of the AF auxiliary light, and the two flashes 16A and 16B having different irradiation distances are selectively used. Since the irradiation angle is narrow, it is not possible to irradiate the whole at the time of wide-angle shooting. Therefore, it is preferable that the user can confirm the irradiation range in advance. As a method for the user to check the irradiation range of the flash light, as shown in FIG. 7A, there is a method in which the irradiation range of the flash light is displayed on the monitor 28 together with the through image. Hereinafter, a method for displaying the flash light irradiation range will be described.

  FIG. 8 is a flowchart showing a processing procedure when shooting is performed while displaying the flash light irradiation range.

  When the camera mode is set to the shooting mode (step S51), the CPU 110 executes through image display processing according to a predetermined control program (step S52). The photographer adjusts the angle of view by operating the zoom button 30 while viewing the through image displayed on the monitor 28. Then, the shutter button 22 is half-pressed to give an AF instruction.

  The CPU 110 determines whether or not the shutter button 22 is half-pressed based on the input from the operation unit 112 (step S53). If it is determined that the shutter button 22 is half-pressed, AF processing is executed according to a predetermined control program (step S54). At this time, the CPU 110 emits AF auxiliary light from the AF auxiliary light lamp 20 with a preset initial light emission amount, and executes AF processing.

  From the result of the AF process, the CPU 110 determines whether or not AF is successful (step S55).

  If it is determined that the AF has failed, the CPU 110 determines whether or not the light emission amount of the AF auxiliary light has reached a limit value (step S56). When determining that the light emission amount of the AF auxiliary light has not reached the limit value, the CPU 110 increases the light emission amount of the AF auxiliary light by one level (step S57), and again under the new light emission amount of the AF auxiliary light. AF processing is executed (step S54).

  Thereafter, the CPU 110 again determines the success or failure of the AF from the result of the AF process, and determines whether or not the subject is in focus (step S55).

  As described above, when an AF error occurs, the AF processing is executed by increasing the light emission amount of the AF auxiliary light step by step. If it is determined that AF has succeeded (focused), the CPU 110 determines a flash to be used based on the amount of AF auxiliary light emitted at the time of focusing (step S58). That is, the light emission amount of the AF auxiliary light at the time of focusing is compared with a preset threshold value, and if it is less than the threshold value, the first flash 16A is set as a flash used at the time of actual photographing. On the other hand, if the amount of AF auxiliary light emitted at the time of in-focus is equal to or greater than the threshold, the second flash 16B is set as a flash to be used during the main photographing.

  Thereafter, the CPU 110 performs an exposure condition determination process according to the control program (step S59), and performs a flash light irradiation range calculation process (step S60).

  The calculation process of the flash light irradiation range includes information on the currently set focal length (or zoom ratio) of the photographing lens 14, information on the subject distance estimated from the light emission amount of the AF auxiliary light, and flash irradiation. Based on the angle information.

  Since the flash irradiation angle is constant in the digital camera according to the present embodiment, it is estimated from the currently set information on the focal length (or zoom ratio) of the photographing lens 14 and the light emission amount of the AF auxiliary light. The flash irradiation range is calculated based on the subject distance information.

  In the digital camera of the present embodiment, since the first flash 16A can be used in the entire zoom area, the flash irradiation range is calculated only when the second flash 16B is used.

  After calculating the flash irradiation range, the CPU 110 determines whether the currently set photographing range exceeds the flash irradiation range based on the calculation result (step S61). If it is determined that the currently set photographing range exceeds the flash irradiation range, the flash irradiation is superimposed on the through image displayed on the monitor 28 as shown in FIG. 7A. A frame representing the range is displayed (step S62). In addition to this, a predetermined warning, for example, a message indicating that the photographing range exceeds the irradiation range may be displayed on the monitor 28 or a warning sound may be sounded.

  The photographer confirms the flash irradiation range by viewing the display on the monitor 28. Then, if necessary, the zoom button 30 is operated (the zoom is operated to the tele side), and as shown in FIG. 7 (b9), the photographing range is adjusted to be within the flash irradiation range.

  Thereafter, the CPU 110 determines whether or not the half-press of the shutter button 22 has been released based on the input from the operation unit 112 (step S64). If it is determined that the half-press has been released, the CPU 110 returns to the process of step S53 and again. Determine if half-pressed.

  On the other hand, when determining that the half-press of the shutter button 22 has not been released, the CPU 110 determines whether or not the shutter button 22 is fully pressed based on an input from the operation unit 112 (step S64), and the shutter button 22 is fully pressed. If it is determined that the button has been pressed, actual photographing / recording processing is executed (step S65).

  If it is determined in step S56 that the light emission amount of the AF auxiliary light has reached the limit value, the CPU 110 performs a predetermined error warning process (step S66) and ends the process.

  As described above, when the shooting range exceeds the flash light irradiation range, the flash light irradiation range is displayed on the monitor 28, whereby appropriate flash shooting can be performed.

  The display of the flash light irradiation range may be arbitrarily turned ON / OFF by the user's setting.

  In the above example, the flash light irradiation range is displayed on the monitor 28 only when the shooting range exceeds the flash light irradiation range. However, the shooting range exceeds the flash light irradiation range. Even in the case where it is not, the irradiation range of the flash light may be displayed on the monitor 28. In this case, it may be notified that the entire range can be irradiated (for example, a message is displayed on the monitor 28).

  Next, a case where flash photography is performed using the fact that two flashes are mounted and one of them is used as a pre-flash will be described.

  As described above, the digital camera 10 of the present embodiment includes the first flash 16A with a wide irradiation angle and a short irradiation distance, and the second flash 16B with a narrow irradiation angle and a long irradiation distance.

  At the time of actual photographing, the flash to be used is properly used according to the light emission amount of the AF auxiliary light, and only one of the flashes is used.

  Therefore, when the first flash 16A having a wide irradiation angle is used during the main photographing, the second flash 16B is used as a pre-flash and the main flash is reflected from the subject reflected light when the second flash 16B is pre-flash. It is configured to set the exposure conditions during shooting.

  FIG. 9 is a flowchart showing a processing procedure of the digital camera when one of the flashes is used for pre-flash and photographing is performed.

  When the camera mode is set to the shooting mode (step S71), the CPU 110 executes through image display processing according to a predetermined control program (step S72). The photographer adjusts the angle of view by operating the zoom button 30 while viewing the through image displayed on the monitor 28. Then, the shutter button 22 is half-pressed to give an AF instruction.

  The CPU 110 determines whether or not the shutter button 22 is half-pressed based on the input from the operation unit 112 (step S73). If it is determined that the shutter button 22 is half-pressed, AF processing is executed according to a predetermined control program (step S74). At this time, the CPU 110 emits AF auxiliary light from the AF auxiliary light lamp 20 with a preset initial light emission amount, and executes AF processing.

  From the result of the AF process, the CPU 110 determines whether or not AF is successful (step S75).

  If it is determined that the AF has failed, the CPU 110 determines whether or not the light emission amount of the AF auxiliary light has reached a limit value (step S76). When determining that the light emission amount of the AF auxiliary light has not reached the limit value, the CPU 110 increases the light emission amount of the AF auxiliary light by one level (step S77), and again under the new light emission amount of the AF auxiliary light. AF processing is executed (step S74).

  Thereafter, the CPU 110 again determines the success or failure of the AF from the result of the AF process, and determines whether or not the subject is in focus (step S75).

  As described above, when an AF error occurs, the AF processing is executed by increasing the light emission amount of the AF auxiliary light step by step. If it is determined that AF is successful, the CPU 110 determines a flash to be used based on the amount of AF auxiliary light emitted at the time of focusing (step S78). That is, the light emission amount of the AF auxiliary light at the time of focusing is compared with a preset threshold value, and if it is less than the threshold value, the first flash 16A is set as a flash used at the time of actual photographing. On the other hand, if the amount of AF auxiliary light emitted at the time of in-focus is equal to or greater than the threshold, the second flash 16B is set as a flash to be used during the main photographing.

  Thereafter, the CPU 110 determines whether or not the first flash 16A is used for the main photographing (step S79), and if it is determined that the first flash 16A is used for the main photographing, the second flash 16B is pre-flashed (step S80). ). Then, based on the subject reflected light of the flash light of the second flash 16B that has been pre-flashed, the exposure at the time of actual photographing is determined (step S81).

  Note that the method for obtaining the exposure condition at the time of actual photographing by pre-flashing the flash is a known technique, and therefore, the description of the specific processing contents is omitted here.

  On the other hand, when determining that the first flash 16A is not used for the main photographing, the CPU 110 performs an exposure determination process without pre-flashing the flash (step S82). In this case, the first flash 16A is not pre-flashed because the flash light of the first flash 16A does not reach the subject.

  Thereafter, the CPU 110 determines whether or not the half-press of the shutter button 22 has been released based on the input from the operation unit 112 (step S83). If it is determined that the half-press has been released, the CPU 110 returns to the process of step S73 and again. Determine if half-pressed.

  On the other hand, when determining that the half-press of the shutter button 22 has not been released, the CPU 110 determines whether or not the shutter button 22 is fully pressed based on an input from the operation unit 112 (step S84), and the shutter button 22 is fully pressed. If it is determined that the button has been pressed, the main photographing / recording process is executed (step S85).

  If it is determined in step S76 that the emission amount of the AF auxiliary light has reached the limit value, the CPU 110 performs a predetermined error warning process (step S86), and then ends the process.

  As described above, when the first flash 16A having a wide irradiation angle is used at the time of actual photographing, the reflected light from the subject when the second flash 16B is used as a pre-flash and the second flash 16B is pre-flash is used. From this, it is possible to perform more appropriate flash photography by determining the exposure conditions during actual photography.

  As described above, the pre-flash of the flash is only for the case where the first flash 16A is used for the main photographing. Therefore, when the second flash 16B is used for the main photographing, from the viewpoint of preventing camera shake, It is preferable to determine the exposure condition so that the shutter speed is equal to or higher than a prescribed shutter speed (so-called shutter speed priority AE). That is, when determining the exposure condition in step S82, the exposure condition is set in accordance with a predetermined control program so as to be equal to or higher than a prescribed shutter speed. In this case, the sensitivity may be automatically increased to a specified value. Thereby, it is possible to take a picture while preventing camera shake even in a dark environment.

  In the above example, when the second flash 16B is pre-flashed, the second flash 16B is pre-flashed when the shutter button 22 is half-pressed. However, after the shutter button 22 is fully pressed, the second flash 16B is flashed. May be pre-flashed to determine the exposure condition, and then the actual shooting may be performed.

  In the flowchart shown in FIG. 9, the flash irradiation range display process is not performed, but the flash irradiation range is calculated in the same manner as described above, and if the shooting range exceeds the flash irradiation range, the monitor It is preferable to display the flash irradiation range at 28.

  In the above embodiment, two flashes are mounted on the camera, but the number of flashes mounted on the camera is not limited to this. It is only necessary to mount at least two flashes, and for example, three or four flashes may be mounted. In this case, flashes having different irradiation distances are used. For example, when three flashes are mounted, they are selectively used as a short distance, a middle distance, and a long distance according to the light emission amount of the AF auxiliary light.

  In the above embodiment, the irradiation angle is changed together with the irradiation distance of each flash, but only the irradiation distance may be changed at the same irradiation angle.

  In the above embodiment, the case where the present invention is applied to a digital camera has been described as an example. However, the application of the present invention is not limited to this. For example, the present invention can be similarly applied to a mobile device having an imaging function such as a mobile phone with a camera.

Front perspective view showing external configuration of digital camera Rear perspective view showing external configuration of digital camera Diagram showing the relationship between the irradiation distance and irradiation angle of each flash mounted on a digital camera Block diagram showing the electrical configuration of the digital camera Flow chart showing processing procedure at the time of flash photography A flowchart showing a procedure of processing when shooting is performed by switching the flash in conjunction with switching of the light emission amount of AF auxiliary light. The figure which shows the example of a display of the frame which shows the irradiation range of flash light Flow chart showing the processing procedure for shooting with the flash light irradiation range displayed Flowchart showing the procedure of processing when flash photography is performed using one of the flashes for pre-flash

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Digital camera, 12 ... Camera body, 14 ... Shooting lens, 16 ... Flash, 18 ... Self-timer lamp, 20 ... AF auxiliary light lamp, 22 ... Shutter button, 24 ... Mode lever, 26 ... Power button, 28 ... Monitor , 30 ... Zoom button, 32 ... Play button, 34 ... Function button, 36 ... Cross button, 38 ... MENU / OK button, 40 ... DISP / BACK button, 110 ... CPU, 112 ... Operation unit, 114 ... ROM, 116 ... RAM 118, EEPROM, 120, VRAM 124, photographing optical system, 124A, drive unit, 126, photographing optical system drive control unit, 128, image pickup device, 130, timing generator, 132, analog signal processing unit, 134, A / D converter, 136 ... image input controller, 138 ... image signal Processing unit, 140 ... Compression / decompression processing unit, 144 ... Media controller, 146 ... Memory card, 148 ... Display control unit, 152 ... AE / AWB detection unit, 154 ... AF detection unit, 156 ... Flash control unit, 158 ... AF assist Light lamp controller

Claims (4)

In an imaging device that captures an image of a subject with an imaging unit via a photographing lens,
AF control means for performing AF processing of the photographing lens based on an image obtained from the imaging means before the main photographing;
A plurality of flash emission means having different irradiation distances;
AF auxiliary light emitting means for emitting AF auxiliary light toward the subject;
An AF auxiliary light emission control means for controlling the emission of AF auxiliary light by the AF auxiliary light emission means based on the result of the AF processing, wherein the light emission amount is increased stepwise at the time of AF error from the AF auxiliary light emission means. AF auxiliary light emission control means for emitting AF auxiliary light;
A setting means for setting a flash light emitting means to be used for actual photographing from among the plurality of flash light emitting means, wherein the main photographing is performed according to the amount of AF auxiliary light emitted from the AF auxiliary light emitting means at the time of focusing. Setting means for setting the flash emission means to be used for,
A flash emission control means for controlling the flash emission by the plurality of flash emission means, the flash emission control means for emitting a flash from the flash emission means set by the setting means;
An imaging apparatus comprising: Display means;
An irradiation range calculating means for calculating an irradiation range of the flash light emitting means used for the actual photographing;
A display control unit that displays an image obtained from the imaging unit on the display unit, and displays a frame indicating the irradiation range on the display unit so as to overlap the image;
The imaging apparatus according to claim 1, further comprising: A shooting condition determining means for determining shooting conditions at the time of main shooting based on an image obtained from the imaging means before the main shooting;
When there is a flash light emitting unit having an irradiation distance longer than the flash light emitting unit set by the setting unit, the flash light emission control unit has a flash light emitting unit having an irradiation distance longer than the flash light emitting unit set by the setting unit. The pre-light emission, while the photographing condition determining means determines the photographing condition at the time of main photographing based on an image obtained from the imaging means when the flash light emitting means is pre-lighted. 2. The imaging device according to 2.   When there is no flash light emitting unit whose irradiation distance is longer than the flash light emitting unit set by the setting unit, the photographing condition determining unit determines the photographing condition at the time of the main photographing so as to be equal to or higher than a predetermined shutter speed. The imaging apparatus according to claim 3.

Images