JP2008046341A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera with which the setting of an external stroboscopic unit is facilitated. <P>SOLUTION: When the camera is set to an external stroboscope mode, a CPU controls an LCD driver to display a through-image 85 on an LCD 26, acquires a photometric value from an AE/AF detection circuit and sets the exposure value. Thereafter, the CPU sets the aperture value and the shutter speed based on the exposure value and displays the set aperture value on the LCD 26. Furthermore, the CPU acquires a zoom position from a focal distance detection part. When the focal distance is changed, the CPU determines an effective aperture value so that the exposure value will not change due to the change in the open aperture value. When the effective aperture value is different from the set aperture value, the CPU controls the LCD driver to display a character string 87 together with the set aperture value 86, showing that the aperture value is not a true value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera that can change the focal length of a photographic lens and is detachably mounted with an external strobe device.

  Conventionally, in a digital camera, a light receiving sensor is provided on the front of the camera, and the light emission amount of the strobe is controlled based on the amount of light detected by the light receiving sensor. However, since a change occurs in the aperture value during zooming of the photographing lens and the finder lens, there is a problem that it is difficult to properly control the light emission amount of the strobe.

In order to solve such a problem, the photographic lens and the light receiving sensor unit are determined by determining the light control amount for controlling the light emission amount of the strobe based on the aperture value of the photographic lens and the aperture value of the finder lens. There is known a camera that eliminates the difference in aperture value change during zooming (see, for example, Patent Document 1).
JP 2005-114835 A

  However, although the camera described in Patent Document 1 is effective for a built-in strobe device or a camera having a contact for light control, an external strobe unit is attached to a camera that does not have a contact for light control. When shooting, the aperture value of the taking lens changes when the focal length is changed, and it is necessary to input the aperture value to the external strobe unit. was there.

  The present invention has been made in view of the above circumstances, and even when an external strobe unit is used with a camera that does not have a contact for light control, the external strobe unit can be easily set. The purpose is to provide a camera.

  In order to solve the above problems, the camera of the present invention can change the focal length of the taking lens, and is detachably mounted with an external strobe unit that automatically adjusts light based on the aperture value input by the photographer. A photometric means for measuring subject brightness, an exposure value setting means for setting an optimal exposure value based on a photometric value of the photometric means, and the exposure value set by the exposure value setting means. The aperture value setting means for setting the aperture value based on the display, the display means for displaying the set aperture value set by the aperture value setting means, and the external flash mode for shooting using the external flash unit are set. In this case, when the open aperture value of the photographic lens changes due to the change in the focal length, the aperture value is changed so that the exposure value does not fluctuate, and the display means is controlled. To, together with the aperture value setting, the aperture value setting is characterized in that it comprises a control means for displaying that it is not true value.

  When the aperture value becomes a predetermined threshold value due to the change of the focal length, the image pickup unit includes an imaging unit that images the subject by photoelectric conversion, and an amplification unit that amplifies the imaging signal output from the imaging unit. It is preferable to adjust the gain of the amplification means so that the exposure value does not fluctuate.

  Further, when the external strobe mode is set, when the release button is operated to perform the photographing process, the exposure value setting means sets the exposure value to 0 as compared with the case of photographing using the built-in strobe. It is preferable to set it to a value reduced by .8 to 1.5 EV. In addition, when the subject distance detected by the distance measuring unit is equal to or less than a predetermined distance, the exposure value setting unit is configured to detect the subject distance when detecting the subject distance. Is preferably set to a value obtained by further reducing 0.8 to 1.5 EV. The predetermined distance is a subject distance that may be overexposed by the strobe light of the external strobe unit, for example, 5 m, and can be changed as appropriate.

  Furthermore, a mounting portion to which the external strobe unit is mounted, and detection means for detecting that the external strobe unit has been mounted to the mounting portion, the mounting of the external strobe unit by the detecting means. It is preferable that the external strobe mode is automatically set when it is detected.

  In addition, after the external strobe unit is mounted, the aperture value is updated on the display unit based on the change in the focal length until a photographer inputs an aperture value to the external strobe unit. Are preferably displayed.

  According to the camera of the present invention, the set aperture value set by photometry is displayed, and even when the focal length is changed, the aperture value is changed so that the exposure value is not changed. Displays that the aperture value is not a true value, so even if the focal length of the photographic lens is changed, the set aperture value can be input to the external flash unit without being aware of the fluctuation in the open aperture value of the photographic lens. Can do. For this reason, it is possible to easily set the external strobe unit.

  Even if the aperture value of the photographing lens cannot be changed by changing the aperture value, the exposure value can be kept constant by changing the photographing sensitivity by adjusting the gain of the amplification means.

  Further, when the external flash mode is set, overexposure is prevented by setting the exposure value to a value obtained by reducing the exposure value by 0.8 to 1.5 EV compared to the case of shooting using the built-in flash. In addition, it is possible to prevent subject blurring due to the low-speed shutter. Similarly, when the subject distance is equal to or smaller than the predetermined distance, similarly, by setting the exposure value to a value obtained by subtracting 0.8 to 1.5 EV, overexposure and subject blur can be prevented.

  Since the external strobe unit is detected and automatically set to the external strobe mode, it is possible to improve operability and prevent an operation error. Also, after the external strobe unit is attached, the aperture value is updated and displayed based on the change in focal length until the photographer inputs the aperture value to the external strobe unit. The photographer can recognize the true value of the aperture value until the aperture value is input.

  A digital camera 10 shown in FIG. 1 includes a lens barrel 13 having a photographing lens 12 on the front surface of a camera body 11. The digital camera 10 is an interchangeable lens digital camera, and the lens barrel 13 is detachably attached to the camera body 11. Also, a mounting release button 14 is provided in the vicinity of the lens barrel 13. The lens barrel 13 can be removed from the camera body 11 by pressing the mounting release button 14.

  The lens barrel 13 includes a zoom ring 15 and a focus ring 16. The zoom ring 15 is operated when changing the focal length of the photographic lens 12. The focus ring 16 is rotated by the photographer when the manual focus mode is set, and the focus is adjusted.

  Further, an external AF sensor 17 serving as a distance measuring unit that measures the subject distance is provided on the front surface of the camera body 11. The external AF sensor 17 is an active AF sensor, and includes a light projecting unit 17a that irradiates infrared rays toward a subject and a light receiving unit 17b that receives reflected light.

  A power lever 20, a release button 21, a mode selection dial 22, a hot shoe 23, and a pop-up button 24 are provided on the upper surface of the camera body 11. The power supply lever 20 is rotated by the photographer, and the power supply of the camera body 11 is turned on / off. The release button 21 is a two-stage press button, and when it is half-pressed, a shooting preparation process is executed, and when it is fully pressed, a shooting process is executed.

  The mode selection dial 22 is rotated when a desired operation mode is selected from a plurality of operation modes. The plurality of operation modes include, for example, a shooting mode, a playback mode for playing back and displaying a shot image, a setup mode for performing various settings, and the like. The hot shoe 23 is a mounting portion for mounting the external strobe unit 40. The pop-up button 24 is pressed when shooting using the built-in strobe device (see FIG. 4) 81, and the light emission window of the built-in strobe device 81 is arranged on the front surface of the camera body 11.

  Also, as shown in FIG. 2, on the back of the camera body 11, an electronic viewfinder (EVF) 25 that is looked into when framing a subject, a through image, various setting screens, a reproduced image, An LCD 26 is provided as a display means for displaying a set aperture value and the like.

  Further, a menu button 27, a cross cursor key 28, a display button 29, a switching button 30, and a focus lever 31 are provided on the rear surface. The menu button 27 is pressed when displaying a menu screen. The cross cursor key 28 is pressed when moving the cursor in the menu screen to select various items, and the menu button 27 is also pressed when determining the selected item. .

  The display button 29 is pressed when turning on / off the power of the LCD 26. The switching button 30 is operated when switching the display of the through image between the EVF 25 and the LCD 26. The focus lever 31 is operated when switching between the manual focus mode and the autofocus mode.

  A USB connector 32 and a memory card slot 33 are provided on the side surface of the camera body 11. A USB cable is inserted into the USB connector 32 when the camera body 11 and an external peripheral device (for example, a personal computer) are connected. A memory card (see FIG. 4), which is a recording medium on which image data is recorded, is detachably inserted into the memory card slot 33.

  Next, the configuration of the external strobe unit 40 will be described. As shown in FIG. 1, the external strobe unit 40 includes a strobe light emission window 41 and a light receiving sensor 42 on the front surface, and the light receiving sensor 42 receives the reflected light of the strobe light and detects the amount of light. . Further, a connection projection 43 is provided on the lower surface. The projection 43 has a shape corresponding to the hot shoe 23 described above, and the external strobe unit 40 is fixed to the camera body 11 by being fitted into the hot shoe 23.

  As shown in FIG. 3, an operation unit 44 and an LCD 45 are provided on the back surface of the external flash unit 40. The photographer views the aperture value displayed on the LCD 26 of the digital camera 10 and operates the operation unit 44 to input the aperture value to the external flash unit 40. In addition, information such as setting contents is displayed on the LCD 45.

  The external flash unit 40 sets an appropriate amount of light based on the aperture value input by the photographer, and automatically stops light emission and automatically when the amount of light detected by the light receiving sensor 42 reaches the appropriate amount of light. Perform dimming. The case where the appropriate light amount is set based on the aperture value has been described as an example. However, the present invention is not limited to this. The amount of light incident on the light receiving sensor 42 may be adjusted according to the aperture value input by the operation unit.

  Next, the electrical configuration of the digital camera 10 will be described. As shown in FIG. 4, the digital camera 10 includes a CPU 50 that is a control unit that controls each unit in the camera. The photographing lens 12 includes a zoom lens 51, a focus lens 52, and a diaphragm 53. The zoom lens 51 is moved in the optical axis direction between the wide end and the tele end when the zoom ring 15 described above is rotated, and the focal length of the photographing lens is changed.

  Further, a focal length detection unit 54 is connected to the CPU 50. The focal length detection unit 54 outputs focal length information to the CPU 50 based on the position of the zoom lens 51. Note that the focal length detection unit 54 acquires position information of the zoom lens 51 based on, for example, a resistance value that changes as the zoom lens 51 moves, and detects the focal length based on the position information.

  Further, the focus lens 52 is moved in the optical axis direction when the focus ring 16 described above is operated to perform focus adjustment. When the focus lever 31 is set to auto focus, the focus lens 52 is moved in the optical axis direction by the motor 55.

  The aperture 53 is driven by a motor 56 to change the aperture diameter, and controls the amount of subject light incident on the light receiving surface of a CCD image sensor (hereinafter referred to as CCD) 57 as an imaging means. The motors 55 and 56 are connected to the CPU 50 via a motor driver 58. The motor driver 58 transmits drive pulses to the motors 55 and 56 based on a control signal from the CPU 50. The motors 55 and 56 are rotationally driven according to this drive pulse. As the motors 55 and 56, for example, stepping motors are used.

  The CCD 57 is disposed behind the photographing lens 12, and a large number of pixels (photodiodes) are two-dimensionally arranged on the light receiving surface. The subject light that has passed through the photographic lens 12 is incident on the light-receiving surface of the CCD 57 after being incident with the light amount adjusted by the diaphragm 53. The CCD 57 outputs an imaging signal by photoelectrically converting an optical image formed on the light receiving surface. The CCD 57 is connected to the CPU 50 via a timing generator (TG) 60, and the shutter speed of the electronic shutter is determined by a timing signal (clock pulse) input from the TG 60.

  A correlated double sampling circuit (CDS) 61, an AMP 62, and an A / D converter 63 are connected to the CCD 57. The noise component of the imaging signal is removed by the CDS 61, and the AMP 62 amplifies the imaging signal with a preset gain and outputs the amplified signal to the A / D converter 63.

  The A / D converter 63 converts the imaging signal, which is an analog signal, into digital signal image data (CCD RAW data), and outputs the image data to the image signal processing unit 64. The image signal processing unit 64 is connected to the SDRAM 66 through the data bus 65 and temporarily stores the image data in the SDRAM 66. Note that when displaying a through image before shooting, low-resolution image data is stored in the SDRAM 66, and when the release button 21 is fully pressed and main exposure is performed, high-resolution image data is stored.

  When image data is stored in the SDRAM 66, the image signal processing unit 64 performs various image processing such as white balance correction processing, gradation conversion processing, RGB interpolation processing, and YC conversion processing on the image data. Apply to data.

  In addition to the CPU 50 and SDRAM 66, the LCD driver 67, compression / decompression processing circuit 68, media controller 69, AE / AF detection circuit 70, ROM 71, and communication I / F 72 are connected to the data bus 65 described above.

  When displaying a through image, low-resolution image data that has been subjected to various types of image processing is sequentially read from the SDRAM 66 in accordance with instructions from the CPU 50, and is output to the LCD driver 67. The image data is converted into a signal that can be displayed on the LCD 26 or the EVF 25 by the LCD driver 67 and displayed on the LCD 26 or the EVF 25 as a through image.

  When the release button 21 is fully pressed and the photographing process is executed, the compression / decompression processing circuit 68 compresses the high-resolution image data subjected to various image processes in a compression format such as JPEG. Apply. Thereafter, the image data is recorded on the memory card 75 by the media controller 69. When reproducing a recorded image, the compression / decompression processing circuit 68 performs an expansion process on the image data read by the media controller 69. Thereafter, the image data subjected to the decompression process is displayed on the LCD 26.

  The AE / AF detection circuit 70 is a photometric unit that measures the subject luminance, calculates a photometric value representing the subject luminance based on the image data stored in the SDRAM 66, and outputs the photometric value to the CPU 50. The CPU 50 is an exposure value setting unit and an aperture value setting unit, and sets an optimal exposure value based on the photometric value acquired from the AE / AF detection circuit 70, and also sets an aperture value and a shutter speed corresponding to the exposure value. Set.

  The CPU 50 changes the aperture diameter of the aperture 52 by controlling the motor 56 via the motor driver 58 based on the aperture value, and further controls the electronic shutter speed of the CCD 57 based on the shutter speed.

  Further, the AE / AF detection circuit 70 performs AF processing together with the above-described photometry processing. That is, the AE / AF detection circuit 70 calculates an AF evaluation value (amplitude value of the high frequency component) representing the contrast of the image based on the image data converted into a digital signal by the A / D converter 63, and this AF The evaluation value is output to the CPU 50. The CPU 50 acquires the AF evaluation value while moving the focus lens 53 in the optical axis direction when the autofocus mode is set, and moves the focus lens 53 to a position where the AF evaluation value reaches a peak. .

  The ROM 71 stores an aperture value table 70a. The aperture value table 70a is a table for referring to an open aperture value corresponding to each focal length. That is, when the focal length is changed, the CPU 50 refers to the aperture value table 70a to obtain the full aperture value, and determines the effective aperture value so that the exposure value does not change due to the change in the wide aperture value. In the present embodiment, the aperture table 70a is described as a reference table of open aperture values corresponding to each focal length. However, the present invention is not limited to this, and for example, referring to aperture values corresponding to focal lengths and exposure values. It can be a table.

  A USB connector 32 is connected to the communication I / F 72. The communication I / F 72 is controlled by the CPU 50 and communicates with an external peripheral device (for example, a personal computer) connected to the USB connector 32.

  Further, the external AF sensor 17, the release button 21, the operation unit 80, the EEPROM 81, and the built-in flash device 82 are connected to the CPU 50 described above. As described above, the external AF sensor 17 is an active AF sensor, detects the subject distance based on the time until the reflected infrared light irradiated to the subject is received, and sends the subject distance information to the CPU 50. Output. Note that the external AF sensor is not limited to using infrared rays, and for example, a sensor that detects an object distance using ultrasonic waves may be used.

  When the release button 21 is pressed halfway when the autofocus mode is set, the CPU 50 moves the focus lens 53 to the in-focus position based on the subject distance information acquired from the external AF sensor 17. Thereafter, the CPU 50 finely adjusts the in-focus position of the focus lens 53 based on the AF evaluation value acquired from the AE / AF detection circuit 70 described above.

  The operation unit 80 includes a power lever 20, a mode selection dial 22, a menu button 27, a cross cursor key 28, a display button 29, a switching button 30, and a focus switching lever 31. The CPU 50 acquires operation signals from the release button 21 and the operation unit 80 and executes processing corresponding to each operation signal.

  The EEPROM 81 stores various control programs and setting information. The CPU 50 reads these pieces of information from the EEPROM 81 to the SDRAM 66, which is a working memory, and executes various processes based on these pieces of information.

  Further, when performing flash photography using the built-in strobe device 28, the CPU 50 causes the built-in strobe device 82 to emit light in synchronization with the operation of the release button 21 and adjusts the amount of light emitted.

  Next, photographing processing of the digital camera 10 having the above configuration will be described with reference to the flowchart of FIG. An example in which the initial position of the zoom lens 51 is the wide end will be described below.

  When the photographing mode is set by the mode selection dial 22, the CPU 50 controls the LCD driver 67 to display a through image on the LCD 26. Thereafter, the CPU 50 determines whether or not the external strobe mode is set. This determination is made based on whether or not the external strobe mode is set by the operation unit 80. If it is determined that the external strobe mode is not set, the process proceeds to a process for determining whether or not the release button 21 is half-pressed.

  If it is determined that the external strobe mode is set, the CPU 50 acquires a photometric value from the AE / AF detection circuit 70 and sets an optimum exposure value corresponding to the photometric value. Further, the CPU 50 sets an aperture value based on the exposure value and causes the LCD 26 to display the set aperture value. The set aperture value is an aperture value at the wide end (short focus) side when the zoom lens 51 is at the wide end. Further, the focus lens 53 is moved to the in-focus position based on the AF evaluation value.

  Thereafter, the CPU 50 acquires focal length information from the focal length detection unit 54. The CPU 50 determines the effective aperture value by referring to the aperture table based on the focal length information. That is, when the zoom lens 51 is moved from the wide end to the tele end side, the focal length of the photographing lens 12 increases, the brightness of the photographing lens 12 becomes dark, and the open aperture value increases. For this reason, the effective aperture value is set to a value smaller than the set aperture value so that the exposure value does not change.

  The CPU 50 determines whether or not the set aperture value is larger than the effective aperture value. If it is determined that the set aperture value is not larger than the effective aperture value, the “set aperture value” is still displayed on the LCD 26 (the state shown in FIG. 6A). Thereafter, the process proceeds to a process for determining whether or not the release button 21 is half-pressed.

  When it is determined that the set aperture value is larger than the effective aperture value, the CPU 50 determines whether or not the effective aperture value is a predetermined threshold value, for example, an open aperture value. When it is determined that the effective aperture value is the full aperture value, the CPU 50 determines that the exposure value cannot be kept constant only by the aperture value, and increases the gain of the AMP 62.

  Thereafter, the CPU 50 controls the LCD driver 67 to display on the LCD 26 that the aperture value is not a true value along with the set aperture value. For example, as shown in FIG. 6B, a set aperture value 86 and a character string 86 of “equivalent” are displayed on the LCD 26 so as to overlap the through image. When it is determined that the effective aperture value is not the full aperture value, the display on the LCD 26 is similarly in the state shown in FIG. 6B without changing the gain of the AMP 62.

  Thereafter, the CPU 50 determines whether or not the release button 21 is half-pressed. If it is determined that the button is not half-pressed, the process returns to the process of acquiring focal length information. If it is determined that the button is half-pressed, the CPU 50 executes shooting preparation processing such as AE processing and AF processing.

  When the shooting preparation process ends, the CPU 50 determines whether or not the release button 21 has been fully pressed. When it is determined that the release button 21 is not fully pressed, the standby state is maintained until the release button 21 is fully pressed. If it is determined that the button has been fully pressed, the CPU 50 controls each unit to execute an imaging process. When the external strobe mode is set, the CPU 50 outputs a trigger signal to the external strobe unit 40 in synchronization with the full press of the release button 21, and the external strobe unit 40 is input by the photographer. The flash light is automatically adjusted based on the aperture value. Further, the CPU 50 controls the media controller 69 to record the captured image data in the memory card 75 and ends the photographing process.

  As described above, since the set aperture displayed on the LCD 26 does not change even when the focal length of the taking lens 12 is changed, the photographer is not aware of the fluctuation of the open aperture value of the taking lens 12 and is externally aware. Shoot in strobe mode. In addition, operability is improved because there is no need to re-enter the aperture value in the external flash unit 40.

  In the above description of the photographing process, the case where the exposure value is set in the same way as when the built-in flash device 82 is used has been described. In addition, there is a problem that subject blur occurs due to a low-speed shutter. Hereinafter, photographing processing for preventing such overexposure and subject blur will be described with reference to the flowchart of FIG.

  Since the processing until the release button 21 is half-pressed is the same as the above-described photographing processing, description thereof will be omitted. First, the case where the external flash mode is set will be described. In this case, the CPU 50 determines whether or not the release button 21 is half-pressed. If it is determined that the release button 21 is not half-pressed, the CPU 50 returns to the process of acquiring focal length information.

  If it is determined that the release button 21 is half-pressed, the CPU 50 controls the AE / AF detection circuit 70 to obtain a photometric value. Thereafter, the CPU 50 sets an appropriate exposure value based on the photometric value, and sets the exposure value to a value obtained by subtracting 0.8 to 1.5 EV, for example, 1 EV from the appropriate exposure value. At the same time, AF processing is performed. Thereafter, the process proceeds to a process of determining whether the subject distance is equal to or less than a predetermined distance.

  If it is determined that the external flash mode is not set, the CPU 50 determines whether or not the release button 21 is half-pressed. When it is determined that the release button 21 is not half-pressed, the standby state is maintained until the release button 21 is half-pressed.

  If it is determined that the release button 21 is half-pressed, the CPU 50 controls the AE / AF detection circuit 70 to obtain a photometric value. Thereafter, the CPU 50 sets the appropriate exposure value determined based on the photometric value as the exposure value. At the same time, AF processing is performed. Thereafter, the process proceeds to a process of determining whether the subject distance is equal to or less than a predetermined distance.

  The CPU 50 determines whether or not the subject distance is a predetermined distance (for example, 5 m) or less. When it is determined that the distance is equal to or less than the predetermined distance, the CPU 50 sets the exposure value to a value further reduced by 1 EV. If it is determined that the distance is not less than the predetermined distance, the exposure value is not changed.

  Thereafter, the CPU 50 determines whether or not the release button 21 has been fully pressed. When it is determined that the release button 21 is not fully pressed, the standby state is maintained until the release button 21 is fully pressed. When it is determined that the release button 21 is fully pressed, the CPU 50 controls each unit based on the above-described exposure value setting to execute an imaging process. When the external strobe mode is set, the CPU 50 outputs a trigger signal to the external strobe unit 40 in synchronization with the full press of the release button 21, and the external strobe unit 40 is input by the photographer. The flash light is automatically adjusted based on the aperture value. Further, the CPU 50 controls the media controller 69 to record the captured image data in the memory card 75 and ends the photographing process.

  As described above, when the external strobe mode is set, the exposure value is set to a value obtained by subtracting 0.8 to 1.5 EV from the case of shooting using the built-in strobe so that overexposure is caused. It is possible to prevent subject blurring due to a low-speed shutter. Similarly, when the subject distance is equal to or less than the predetermined distance, overexposure and subject blur can be prevented.

  In the description of the above embodiment, the case where the external strobe mode is set by the photographer's operation has been described. However, the external strobe unit 40 may be detected and automatically set to the external strobe mode. good. Further, the case where the change of the aperture value due to the change of the focal length is not reflected on the display of the LCD 26 regardless of the aperture value setting operation of the external flash unit 40 has been described as an example. The change of the aperture value may be reflected on the display of the LCD 26 before the is input. Hereinafter, these cases will be described.

  As shown in FIG. 8, the digital camera 90 includes an external strobe detection unit 91 that detects that the external strobe unit 40 is attached to the hot shoe 23. The strobe detector 91 is provided on the hot shoe 23 and is connected to the CPU 50 via the data bus 65. When the CPU 50 obtains a detection signal from the strobe detector 91, it automatically sets the external strobe mode. Other configurations are the same as those of the digital camera 10, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  Next, photographing processing in the external strobe mode of the digital camera 90 will be described using the flowchart of FIG. When the photographing mode is set by the mode selection dial 22, the CPU 50 determines whether or not the external flash unit 40 is attached to the hot shoe 23. This determination is made based on whether or not a detection signal has been acquired.

  If it is determined that the external strobe unit 40 is not attached, the standby state is maintained until the external strobe unit 40 is attached. If it is determined that the external strobe unit 40 is attached, the CPU 50 automatically sets the external strobe mode.

  Thereafter, the CPU 50 controls the LCD driver 67 to display a through image, and controls the AE / AF detection circuit 70 to acquire a photometric value, and sets an exposure value based on the photometric value. Further, the CPU 50 sets an aperture value and a shutter speed based on the exposure value, and controls the LCD driver 67 to display the aperture value on the LCD 26.

  Thereafter, the CPU 50 acquires focal length information from the focal length detection unit 54, changes the aperture value so that the exposure value does not change due to the change in the open aperture value, and controls the LCD driver 67 to display the aperture value. Update.

  Thereafter, the CPU 50 determines whether or not an aperture value has been input to the external strobe unit 40. This determination is performed based on, for example, whether or not an operation indicating that the input of the aperture value has been completed is performed by the photographer. If it is determined that the aperture value has not been input, the process returns to the process of acquiring focal length information.

  If it is determined that an aperture value has been input, the CPU 50 performs the same processing as the above-described shooting process using the current aperture value as a set aperture value. That is, the CPU 50 determines the effective aperture value so that the exposure value does not change when the focal length is changed. When the set aperture value and the effective aperture value are different, as shown in FIG. 6B, the LCD driver 67, and the character string 87 of “equivalent” is displayed on the LCD 26 together with the “set aperture value” 86.

  Further, when it is determined that the effective aperture value has reached a predetermined threshold (for example, an open aperture value, a minimum aperture value, etc.), it is determined that the exposure value cannot be kept constant with only the aperture value. The CPU 50 adjusts the gain of the AMP 62 to change the photographing sensitivity so that the exposure value does not change with the change of the focal length. Thereafter, similarly, the character string 87 of “equivalent” is displayed on the LCD 26 together with the set aperture value 86.

  Further, the CPU 50 determines whether or not the release button 21 is half-pressed. If it is determined that the release button 21 is not half-pressed, the process returns to the process of acquiring focal length information, and the process of determining the effective aperture value is repeated. If it is determined that the release button 21 is half-pressed, photometry is performed to set an exposure value, and AF processing is also performed. At this time, similarly to the case described above, the exposure value may be reduced by 0.8 to 1.5 EV.

  Thereafter, the CPU 50 determines whether or not the release button 21 has been fully pressed. When it is determined that the release button 21 is not fully pressed, the standby state is maintained until the release button 21 is fully pressed. If it is determined that the release button 21 has been fully pressed, the CPU 50 outputs a trigger signal to the external strobe unit 40 and controls each unit based on the exposure value described above to execute an imaging process. At this time, the external flash unit 40 automatically adjusts the flash light based on the aperture value input by the photographer. Further, the CPU 50 controls the media controller 67 to record the captured image data in the memory card 75 and ends the shooting process.

  In the above embodiment, the case where the aperture value and the character string indicating that the aperture value is not true is displayed on the LCD has been described as an example. However, the through image is displayed on the EVF by the switching button. If set, the aperture value is displayed on the EVF. Further, a dedicated display means for displaying the aperture value may be provided.

  Further, in the above embodiment, the case where the subject distance is detected by the external AF sensor has been described as an example. However, the present invention is not limited to this, and the CPU acquires from the AE / AF detection circuit when there is no external AF sensor. The subject distance may be detected based on the AF evaluation value, or the subject distance may be detected based on the focus lens position.

  Furthermore, in the above-described embodiment, the case where the shutter speed is controlled only by the electronic shutter has been described as an example. However, the present invention is not limited to this, and the shutter speed may be controlled using both the mechanical shutter and the electronic shutter. .

  Further, in the above embodiment, the digital camera in which the lens barrel is detachably attached to the camera body has been described as an example. However, the present invention is not limited to this, and the lens barrel is provided integrally with the camera body. May be.

  Furthermore, in the above embodiment, the case where the present invention is applied to a digital camera has been described as an example. However, the present invention is not limited to this, and the present invention may be applied to a silver salt camera. In this case, the aperture value is changed from the set aperture value so that the exposure value does not change due to the change of the focal length, and if the change cannot be dealt with only by changing the aperture value, the shutter speed may be changed.

It is a perspective view which shows the structure of the front side of a digital camera. It is a perspective view which shows the structure of the back side of a digital camera. It is a perspective view which shows the structure of an external strobe unit. It is a block diagram which shows the electric constitution of a digital camera. It is a flowchart explaining the imaging | photography process of a digital camera. It is a top view which shows the display screen of LCD. It is a flowchart explaining the imaging | photography process of a digital camera. It is a block diagram which shows the electric constitution of a digital camera, and has shown the case where it sets automatically to external strobe mode. 6 is a flowchart for describing photographing processing in an external strobe mode of a digital camera.

Explanation of symbols

10, 90 Digital camera 11 Camera body 12 Shooting lens 17 External AF sensor 21 Release button 23 Hot shoe 25 EVF
26 LCD
40 External strobe unit 50 CPU
57 CCD
62 AMP
70 AE / AF detection circuit 91 External strobe detector

Claims (6)

In a camera that can change the focal length of the photographic lens and is detachably mounted with an external flash unit that performs automatic light control based on the aperture value input by the photographer.
Metering means for metering subject brightness;
Exposure value setting means for setting an optimal exposure value based on the photometric value of the photometric means;
Aperture value setting means for setting an aperture value based on the exposure value set by the exposure value setting means;
Display means for displaying a set aperture value set by the aperture value setting means;
When the external strobe mode is set to perform shooting using the external strobe unit, the aperture value is set so that the exposure value does not fluctuate when the open aperture value of the photographing lens changes due to the change in the focal length. And a control means for controlling the display means to display that the set aperture value is not a true value along with the set aperture value.   When the aperture value becomes a predetermined threshold value due to the change in the focal length, the exposure value includes an imaging unit that images a subject by photoelectric conversion and an amplification unit that amplifies an imaging signal output from the imaging unit. The camera according to claim 1, wherein the gain of the amplifying unit is adjusted so as not to fluctuate.   When the external flash mode is set, when the release button is operated to perform shooting processing, the exposure value setting means sets the exposure value to 0.8 than when shooting using the built-in flash. 3. The camera according to claim 1, wherein the camera is set to a value obtained by subtracting -1.5 EV.   When the subject distance detected by the distance measuring unit is equal to or less than a predetermined distance, the exposure value setting unit further sets the exposure value when executing the photographing process. 4. The camera according to claim 3, wherein the camera is set to a value obtained by subtracting 0.8 to 1.5 EV.   A mounting unit on which the external strobe unit is mounted; and a detecting unit that detects that the external strobe unit is mounted on the mounting unit. The detecting unit detects the mounting of the external strobe unit. 5. The camera according to claim 1, wherein the camera is automatically set to the external strobe mode.   After the external strobe unit is mounted, the aperture value is updated and displayed on the display means based on the change in the focal length until a photographer inputs an aperture value to the external strobe unit. The camera according to any one of claims 1 to 5, wherein:

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