JP4822283B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus that employs a focus bracket imaging system.

  2. Description of the Related Art Conventionally, photographing apparatuses that employ a focus bracket photographing method are known (see Patent Document 1, Patent Document 2, etc.).

  The focus bracket photographing method is a photographing method for photographing a plurality of images while gradually shifting the focal position.

  In the invention described in Patent Document 1, when the release button is operated, focus bracket photography is performed at a constant interval while driving the focus lens system from an arrangement that focuses in close proximity to the subject to an arrangement that focuses at infinity. .

  After capturing the image, when the photographer selects the subject area that he wants to focus on while looking at the liquid crystal display, the focus is best achieved within the selected subject's peripheral area among the plurality of captured image data. Select an image.

After selecting the image with the best focus, the selected image is recorded on a recording medium, the image is stored, and then the shooting standby state is restored.
JP 2005-277813 A

  By the way, when shooting a subject with depth using a digital camera having an autofocus function, it is extremely difficult to automatically reflect the photographer's intention in the photographed image. It may be shot at the position.

  As a countermeasure for this problem, an imaging method called focus bracket imaging, in which the focus position of the focus lens is slightly moved back and forth from a determined focus position and is shot several times, has been conventionally known.

  However, with this method, even if a slight focus shift can be covered, a large focus shift cannot be covered.

  Therefore, in the invention of Patent Document 1, the focus lens system is driven from an arrangement that focuses in close proximity to the subject to an arrangement that focuses at infinity, and the photographer takes a photographed image after photographing in the entire photographing focus range. When an arbitrary area is designated on the image display unit, an image focused on the designated area is extracted.

  For this purpose, it is ideal to shoot all the focal positions from close to infinity. However, considering the merchantability, avoid limiting the focus range due to memory capacity and processing speed limitations. I can't.

  Moreover, as the subject distance is closer or the focal distance is closer to the telephoto side, the depth of field is sharply narrowed, so a considerable number of times can be taken to change the focal position while maintaining the in-focus state. Shooting is required.

  Although it depends on the specifications of the optical system, for example, in a compact digital camera that currently uses a 1 / 2.5-type 8 million to 10 million pixel image sensor, about 30 images from the closest to infinity on the wide-angle side. On the telephoto side, it is necessary to shoot about 70 images from close to infinity, and only about 10 images can be processed at a time using a 1 Gbit image buffer memory mounted on a single-lens reflex camera.

  Further, in the invention of Patent Document 1, the shooting focus range that can be shot for focus bracket shooting is also limited by the capacity of the image buffer memory, and the focus position must be divided into a plurality of positions from the nearest to infinity. There was no problem.

  Therefore, the present invention provides a photographing apparatus that employs a focus bracket photographing method that enables the photographing according to the photographing intention to be taken, while rationally reducing the number of photographing and saving the recording medium.

In order to achieve the above object, the invention described in claim 1 includes a photographing optical system that forms a subject image, an imaging element that converts the subject image formed by the photographing optical system into an image signal, and the photographing. an image recording means for recording the image data captured while moving at least a portion of the lens provided in the optical system in the optical axis direction, and an image display unit for displaying the photographed image data, wherein prior to shooting a focus evaluation value output means for outputting a focus evaluation value for evaluating the degree of focusing at each lens position while moving at least a portion of the lens in the optical axis direction, the data near the maximum of the focus evaluation value for each lens position Shooting focus range acquisition means for determining a plurality of shooting focus ranges that can be focused on the subject from
Each time the first switch is operated during shooting, the shooting focus range is sequentially displayed on the image display unit, and when the second switch is operated, a plurality of positions are changed while changing the lens position within the shooting focus range being displayed. It is characterized by a photographing device that performs multiple photographing and records each photographed image.

According to a second aspect of the present invention, an imaging optical system that forms a subject image, an imaging element that converts the subject image formed by the imaging optical system into an image signal, and the imaging optical system are provided. An image recording means for recording each image data photographed while moving at least a part of the lens in the optical axis direction , an image display unit for displaying the photographed image data, and the at least a part of the lens prior to photographing a focus evaluation value output means for outputting a focus evaluation value for evaluating the degree of focusing of the allowed while the lens position moving in the optical axis direction, focus on the subject from the data near the maximum of the focus evaluation value for each lens position A shooting focus range acquisition means for determining a plurality of possible shooting focus ranges; and a depth of field acquisition means for acquiring depth of field information at each lens position from the state of the shooting optical system;
Determining a plurality of focus ranges that can be focused from the local maximum value data of at least two focus evaluation values that are included in and close to the depth of field acquired by the depth of field acquisition means;
Each time the first switch is operated during shooting, the shooting focus range is sequentially displayed on the image display unit, and when the second switch is operated, a plurality of positions are changed while changing the lens position within the shooting focus range being displayed. It is characterized by a photographing device that performs multiple photographing and records each photographed image.

Further, in the invention described in claim 3 , the operation of the first switch and the operation of the second switch respectively correspond to a half-pressing operation and a full-pressing operation of the two-stage release SW1. The imaging apparatus according to claim 1 or claim 2 is characterized.

According to the first aspect of the present invention configured as described above, when the first switch is operated, the shooting focus range when shooting a plurality of times while changing the lens position after the second switch is operated is imaged. By displaying a warning on the display, the photographer can check the shooting focus range in advance, so it is possible to take a picture after confirming whether or not the subject is within the shooting focus range. In addition to the reduction, it is easy to obtain a subject image intended by the photographer.

Then, shooting a plurality of imaging focus range for each of operating a first switch sequentially notice displayed on the image display portion during the shadow, the lens position in the photographing range of focus in predictive display when operating the second switch Since each image is recorded by shooting multiple times while changing, the operation of the first switch is repeated until the shooting intention is met, and the second switch is operated when the shooting focus range that matches the shooting intention is selected. By doing so, photographing is performed a plurality of times while changing the lens position within the photographing focus range at this time, and each photographed image can be recorded.

For this reason, shooting is performed multiple times while changing the lens position within the shooting focus range that matches the shooting intention of the photographer, and each shot image is recorded, so that shooting can be performed in the focus state intended by the photographer. It is possible to perform photographing with excellent image quality.

According to the second aspect of the present invention, the shooting focus range is determined based on the focus evaluation value data from the focus evaluation value output means and the depth of field information from the depth of field acquisition means. The photographer can select a photographing focus range that matches the intention more quickly and appropriately as to how to cope when the focal range is determined and a photographing focus range that does not match the photographing intention is displayed in advance.

Further, according to the first or second aspect of the present invention, since the photographing focal range is selected according to the photographing intention of the photographer, photographing is performed a plurality of times while changing the lens position within the photographing focal range. The storage area of the recording means is not wasted.

In addition, according to the third aspect , the first switch operation and the second switch operation are performed by one release SW1 by performing the operation according to the first or second aspect of the invention by performing the operation according to the first or second aspect of the invention. Therefore, operability can be improved.

  Hereinafter, the photographing apparatus of the present invention will be described based on examples.

<Operation principle of autofocus>
The auto focus method includes an active method using an infrared projection LED, a passive method using a phase difference sensor integrated with an optical lens, and a TTL / AF method for guiding light transmitted through a photographing lens to a phase difference sensor. Etc. are known.

  The method used in many compact digital cameras in recent years is called the contrast method (sometimes called the hill-climbing method because of its operation method), which has been known as an autofocus technology for video cameras. is there.

  As the operation principle of the contrast method, the subject light is photographed while changing the position of the focus lens in a minute step, and the high frequency component of each photographing data (the high frequency component of the Fourier coefficient when Fourier transforming the image data) is extracted, This is a method of calculating as an AF evaluation value (integral value (average value) of high-frequency components of Fourier coefficients on the image plane) and determining the in-focus position from the maximum value of the change in the AF evaluation value with respect to the focus lens position.

  As the most general operation method of this method, prior to actual photographing, photographing is performed sequentially while moving the focus lens step by step, high frequency components of photographing data are extracted, and calculated as an AF evaluation value.

  Of the focus lens positions where the AF evaluation value is maximum with respect to the focus lens position, the focus position where the maximum value is maximum is selected as the in-focus position, this position is stored, and when the minute step drive operation ends, The focus lens is moved again to that position, and actual shooting is performed.

  For this reason, although it takes time to determine the in-focus position, it is generally used as a method for obtaining an accurate in-focus position without providing a separate sensor.

<Constitution>
1A and 1B are external views showing a digital camera as a photographing apparatus of the present invention. FIG. 1A is a plan view, FIG. 1B is a front view, and FIG. In FIG. 1, the symbol C is a digital camera.

  As shown in FIG. 1A, a sub liquid crystal display 1 (hereinafter, the liquid crystal display is referred to as “LCD”), a release SW1, and a mode dial SW2 are provided above the digital camera C.

  The release SW 1 is configured so that the focus is locked by a half-press operation, and actual shooting is performed by a full-press operation.

  As shown in FIG. 1B, on the front side of the digital camera C, a lens barrel unit 2 provided with a photographing lens, a light incident part of an optical finder 3, a strobe light emitting part 4, a remote control light receiving part 5, an infrared measurement refusal On one side of the unit 6 and digital camera C, a memory card / battery loading chamber lid 7 is provided.

  As shown in FIG. 1C, on the back side of the digital camera C, the eyepiece of the optical viewfinder 3, the LCD monitor 8, the AF confirmation LED 9, the strobe confirmation LED 10, the zoom switch SW3, the self-timer switch SW4, A menu switch SW5, a cursor movement setting switch SW6, a display switch SW7, an OK switch SW8, and a power switch SW9 are provided.

  Thus, in the digital camera C of the present embodiment, the operation unit S is configured by the SW1 to SW9.

  FIG. 2 is a block diagram showing a system configuration of the digital camera C.

  In FIG. 2, reference numeral 11 denotes a DSP (digital still camera processor). The DSP 11 includes a control calculation unit (CPU unit) 12, an image processing unit 13, a compression / decompression processing unit 14, an image output I / F unit 15, and an image recording. An I / F unit 16 and the like are built in, and these units are connected to each other via a bus line.

  Although the image processing unit 13 has various image processing functions, the AF evaluation value (Fourier) is based on the frequency information of the subject image obtained by the hill-climbing scan (information on the high frequency component of the Fourier coefficient when the image data is Fourier transformed). It also has AF subject frequency information acquisition means 13a for acquiring the integral value (average value) of the high frequency component of the coefficient on the image plane.

  Outside the DSP 11, an image buffer memory 17, a RAM 18, and a program memory 19 in which a control program, parameters, and the like are stored are also connected to the DSP 11 through a bus line.

  Each unit of the digital camera C is controlled by the control calculation unit 12 of the DSP 11.

  The image buffer memory 17 stores RAW-RGB image data (image data subjected to white balance correction and γ correction) converted from image data of a photographed image, YUV image data (brightness data and color difference data). Converted image data) and JPEG image data (JPEG-compressed image data) are stored.

  When the power switch SW9 is turned on, the control program stored in the program memory 19 is loaded into the memory of the DSP 11 and executed, and each part of the digital camera C is controlled by this control program.

  When the control program is executed, the memory of the RAM 18 is used as a working memory for the control program, so that the control data and parameters of the control program are written to and read from the RAM 18 as needed.

  Processing described later is mainly executed by the control calculation unit 12 of the DSP 11 by executing this control program.

  In FIG. 2, reference numeral 20 denotes a photographing optical system that forms a subject image. The photographing optical system 20 includes a photographing lens system 21 that includes a zoom optical system and a focus lens, and a diaphragm / shutter that includes a diaphragm and a mechanical shutter. The unit 22 is configured.

  The photographing lens system 21 and the aperture / shutter unit 22 are driven by an optical system driving unit 23, and the optical system driving unit 23 is controlled by the control calculation unit 12 of the DSP 11.

  The photographing optical system 20 changes the position of the zoom optical system and the focus lens by a mechanical mechanism at the time of focusing, zooming, starting and stopping, and the aperture / shutter unit 22 is adjusted to an appropriate exposure at the time of photographing, and at the time of still image photographing. The shutter is opened and closed.

  During operation of the digital camera C, the focus lens is driven by the optical system drive unit 23 to form a subject image on the light receiving unit of the CMOS image sensor 24.

  An optical low-pass filter 25 for preventing the incidence of ultraviolet rays is provided on the incident side of the light receiving unit of the image sensor 24.

  Although a CCD type may be used as the image pickup element, in this embodiment, a CMOS type image pickup element capable of reading a video signal at a higher speed than the CCD type is used.

  The subject image formed on the light receiving portion of the image sensor 24 by the photographing optical system 20 built in the lens barrel unit 2 is converted into an image signal by the image sensor 24, and this image signal is sent to the FEP (front end processor) 26. Is output.

  The FEP 26 includes a CDS 27 that performs correlated double sampling, a PGA 28 that automatically adjusts the gain, and an ADC 29 that converts an analog image signal output from the PGA 28 into a digital image signal.

  The FEP 26 performs predetermined processing such as noise reduction processing and gain adjustment processing on the analog image signal output from the image sensor 24, further converts the analog image signal into a digital image signal, and the image processing unit 13 of the DSP 11. Output to.

  Timing processing such as sampling of the image signal by the FEP 26 is performed by the TG 30 based on the VD / HD signal fed back from the image processing unit 13 of the DSP 11.

  The control calculation unit 12 of the DSP 11 is connected to each part of the digital camera C such as a strobe circuit that causes the strobe light emitting unit 3 to emit light, and these are controlled and monitored by the control calculation unit 12.

  The control calculation unit 12 is connected to the sub LCD 1, the remote control light receiving unit 5, the AF confirmation LED 9, the strobe confirmation LED 10, the operation unit S including the switches SW 1 to SW 9, a buzzer, and the like via the LCD driver. Is also controlled by the control calculation unit 12.

  The control calculation unit 12 constantly monitors the input state of the signal to the remote control light receiving unit 5 and the input state to the operation unit S.

  The LCD monitor 8 is connected to the image output I / F unit 15 of the DSP 11 via an LCD driver for driving the LCD monitor 8, and an image is output to the LCD monitor 8.

  The LCD monitor 8 is used for monitoring a subject being photographed, displaying a photographed image, and displaying an image recorded on a memory card or a built-in memory.

  The image recording I / F unit 16 is connected to a memory card slot, and exchanges image data between a recording medium such as an additional memory card inserted into the memory card slot and the digital camera.

<Operation of digital camera C>
Next, the basic operation of the digital camera C of this embodiment will be described.

  The operation mode of the digital camera C includes a shooting mode used when shooting, and a playback mode used when playing back the shot image. During operation in the shooting mode, AF (described later) is further performed. There are an area confirmation mode and an AF area selection mode.

  In addition to these, during operation in the shooting mode, various operation modes such as a self-timer mode for shooting using a self-timer and a remote-control mode for remotely operating the digital camera C by a remote controller are prepared. Yes.

  FIG. 3 is a flowchart for explaining an outline of the operation of the digital camera C.

  When the power switch SW9 of the digital camera C is turned on, the processing shown in the flowchart of FIG. 3 is started. This process will be described with reference to FIG.

  When the mode dial SW2 is set to the shooting mode with the power switch SW9 of the digital camera C turned on, the digital camera C enters the shooting mode, and when the mode dial SW2 is set to the playback mode, the digital camera C enters the playback mode. Become.

  Step S. In 1-1, it is determined whether the switch of the mode dial SW2 is in the shooting mode or the playback mode. If the playback mode is selected, the process proceeds to step 1-2. Proceed to processing 1-5.

  Step S. In 1-2, the optical system driving unit 23 is controlled by the control calculation unit 12 of the DSP 11, and the lens barrel constituting the lens barrel unit 2 is moved to a position where photographing can be performed. Further, the imaging device 24, FEP 26, LCD monitor Power is turned on to each circuit required for photographing such as 8.

  Information on the subject image formed on the light receiving portion of the image sensor 24 by the photographing optical system 20 is converted into RGB analog signals by the image sensor 24 as needed, and the RGB analog signals are subjected to noise reduction processing by the CDS 27 and the PGA 28. And predetermined processing such as gain adjustment processing is performed, and the ADC 29 converts the RGB analog signal into an RGB digital signal and outputs the RGB digital signal to the image processing unit 13 of the DSP 11.

  Further, the RGB digital signals are converted into RAW-RGB image data, YUV image data, and JPEG image data by the image processing unit 13 and written into the frame memory of the image buffer memory 17 by a memory controller (not shown).

  Among these image data, YUV image data is read from the frame memory of the image buffer memory 17 as needed, converted into a video signal by the image output I / F unit 15, and output to the LCD monitor 8.

  As described above, in the shooting standby state, the image data of the subject image is taken into the frame memory of the image buffer memory 17 as needed and the subject image is output from the LCD monitor 8 as needed. This process is referred to as a monitoring process.

  Step S. In 1-3, it is determined whether or not the setting of the mode dial SW2 has been changed. Returning to the process of 1-1, if the setting has not been changed, step S. The process proceeds to 1-4.

  Step S. In 1-4, the state of the release SW1 is determined. If the release SW1 is not pressed, step S.1. Returning to the processing of 1-2, when the release SW1 is pressed halfway, the AF area confirmation mode processing or AF area selection mode processing is performed. When the release SW1 is fully pressed, the set shooting is performed. Focus bracket shooting is performed within the focal range.

  Then, the captured image is taken into the frame memory of the image buffer memory 17 and the image data is recorded on the recording medium. The process returns to 1-2. This step S.I. The process 1-4 is referred to as a photographing process.

  As described above, when the digital camera C is operating in the shooting mode, step S. 1-2 to step S.E. The process of 1-4 is repeated. The state in which this repeated processing is performed is referred to as a finder mode. In the digital camera C of this embodiment, these processes are repeated at a constant cycle.

  In this finder mode, the monitoring process is also repeatedly performed at a constant period, and accordingly, the display on the LCD monitor 8 is updated.

  Further, step S.I. In step 1-5, the image data recorded on the recording medium such as the built-in memory or the memory card is output to the LCD monitor 8; The process proceeds to 1-6.

  Step S. At 1-6, it is determined whether or not the setting of the mode dial SW2 has been changed. Returning to the process of 1-1, if the setting has not been changed, step S. The process returns to 1-5.

  In the AF area confirmation mode, as shown in FIG. 5 (b), the focus range in focus bracket shooting is displayed on the LCD monitor 8 before the focus bracket shooting is started, and the photographer confirms the focus range and focuses. It is intended to enable bracket photography.

  The digital camera C according to the first embodiment includes a shooting focus range acquisition unit that determines a shooting focus range that can focus on the subject from data in the vicinity of the maximum value of the AF evaluation value for each focus position. When the half-pressing operation is performed, the shooting focus range is displayed in advance on the LCD monitor 8, and when the release SW1 is fully pressed, AF bracket shooting is performed within the shooting focus range being displayed, and each captured image is recorded. .

<Control flow chart>
FIG. 4 is a flowchart of the shooting process in the AF area confirmation mode.

  Step S. In 2-1, the shooting process in the AF area confirmation mode is started.

  Step S. In 2-2, it is determined whether or not the release SW1 is half pressed. If not half-pressed, step S.E. Returning to 2-1, if it is half-pressed, it proceeds to the next step (S.2-3).

  Step S. In 2-3, the hill-climbing scan process is executed while shifting the focus position of the focus lens of the photographing optical system 20.

  That is, while moving the focus lens from the closest focus position to the infinity focus position, the image information is recorded, and the frequency information of the subject image (Fourier transform of the image data is performed by the AF subject frequency information acquisition unit 13a). AF evaluation value (integral value (average value) of high-frequency component of Fourier coefficient on the image plane) is calculated based on the high-frequency component information of the Fourier coefficient.

  In normal AF (autofocus) processing, there are a plurality of subject distances at which the subject can be focused. Therefore, there are a plurality of AF evaluation value peaks with respect to the subject distance. By referring to the subject at the closest distance in the image, the focus position of the subject having the maximum peak value out of the AF evaluation value peaks is referred to as the in-focus position.

  In this embodiment, the focus position is determined with reference to the focal position of the subject (the person in front of FIG. 5A) having the maximum peak value.

  Step S. In step 2-4, step S.1. Based on the AF evaluation value calculated and recorded in 2-3, the photographing focal range of the focal lens is determined, and the focal lens is moved to a lens position within the photographing focal range.

  The photographing focus range can be set in advance by the user, or can be automatically determined from information such as the open state of the aperture, the state of the photographing lens, and the exposure state at that time.

  In the present embodiment, photographing focus range acquisition means for automatically determining the photographing focus range from the width of the peak graph of the AF evaluation value is provided. Specifically, a graph width such as a half width of a peak graph is used.

  Step S. In 2-5, a notice display of the photographing focus range is displayed on the LCD monitor 8 by the photographing focus range display means for displaying the photographing focus range of the focus bracket photographing on the LCD monitor 8.

  The photographing focus range display means displays a notice display of the photographing focus range on the LCD monitor 8 by program processing.

  Step S. In 2-6, it is determined whether or not the half-pressed state of the release SW1 is held. Returning to 2-1, if the half-pressed state is maintained, the photographing standby state is maintained, and the process proceeds to the next step (S.2-7).

  Step S. In 2-7, it is determined whether or not the release SW1 is fully pressed. If it is not fully pressed, step S.E. Return to 2-6, and if it is fully pressed, proceed to the next step (S.2-8).

  Step S. In step 2-8, step S.1. The so-called focus bracket photographing is performed in which photographing is performed a predetermined number of times or at a predetermined focal position interval while moving the focus lens within the photographing focal range determined in 2-4. Proceed to 2-9.

  Step S. In 2-9, the process ends.

<Function and effect>
When the release SW1 is half-pressed, the shooting focus range when performing the focus bracket shooting is displayed on the LCD monitor 8 in advance so that the photographer can confirm the shooting focus range in advance. It is possible to take a picture after confirming whether or not it is inside, not only reducing photography mistakes but also easily obtaining a subject image intended by the photographer.

  Further, by performing the operations according to the inventions of claims 1 to 3 by the two-stage push release SW1, the first switch operation and the second switch operation can be continuously performed by one release SW1, The operability can be improved.

  If the subject that the photographer intends to shoot is not included in the photographing focus range displayed by the notice display when the photographer half-presses the release SW1, the release SW1 half-pressed state is released. Thus, the hill-climbing scan process is executed again by returning to the initial state and again pressing the release SW 1 halfway, so that the subject intended for photographing is displayed by the notice display by changing the photographing condition. Focusing can be attempted again until it falls within the photographing focus range.

  The present invention will be described based on examples. In addition, description is abbreviate | omitted about the same or equivalent part as the above-mentioned Example, About the code | symbol of drawing, the same code | symbol shall be attached | subjected about the same or equivalent part.

  The digital camera C according to the second embodiment includes a shooting focus range acquisition unit that determines a plurality of shooting focus ranges that can be focused on the subject from data in the vicinity of the maximum value of the AF evaluation value for each focus position. Each time SW1 is pressed halfway, a plurality of shooting focus ranges are sequentially displayed on the LCD monitor 8, and AF bracket shooting is performed within the shooting focus range displayed when the release SW1 is fully pressed. Record each image.

  In the AF area selection mode of the second embodiment, as shown in FIGS. 7B to 7D, the shooting focus range in focus bracket shooting is displayed on the LCD monitor 8 before the focus bracket shooting is started. The focus bracket shooting can be performed after confirming the shooting focus range.

  When the release SW1 is pressed halfway for the first time and the warning focus range for which the focus bracket shooting is performed is out of the shooting intention, the release SW1 is repeatedly pressed halfway to release the release SW1. Each time the button is half-pressed, the shooting focus range is changed and the notice display is switched (in the order of (b) → (c) → (d) in FIG. 7), so the operation is repeated until the shooting intention is met. When a suitable shooting focus range is selected, the release SW1 is fully pressed to perform focus bracket shooting.

<Control flow chart>
FIG. 6 is a flowchart of the AF area selection mode.

  Step S. In 3-1, shooting processing in the AF area selection mode is started.

  Step S. In 3-2, the counter N is set to the initial value 0.

  Step S. In 3-3, it is determined whether or not the release SW1 is half pressed. If not half-pressed, step S.E. Returning to 3-2, if half-pressed, the process proceeds to the next step (S.3-4).

  Step S. In 3-4, it is determined whether or not the value of the counter N is N> 0. If N> 0 is not satisfied (N = 0 in this case), step S. If N> 0, go to step S.3-5a. Proceed to 3-5c.

  Step S. In 3-5a, the hill-climbing scan process is executed while shifting the focus position of the focus lens of the photographing optical system 20.

  That is, while moving the focus lens from the closest focus position to the infinity focus position, the image information is recorded, and the frequency information of the subject image (Fourier transform of the image data is performed by the AF subject frequency information acquisition unit 13a). AF evaluation value (integral value (average value) of high-frequency component of Fourier coefficient on the image plane) is calculated based on the high-frequency component information of the Fourier coefficient.

  In this embodiment, there are a plurality of subject distances that can be focused on, so there are also a plurality of AF evaluation value peaks with respect to the subject distance. In this embodiment, among the AF evaluation value peaks, the peak value Is referred to as the in-focus position with reference to the focal positions of a plurality of subjects that exceed a predetermined threshold.

  Then, the next step S.E. Proceed to 3-5c.

  Step S. In 3-5b, step S.3. 3-5a, the number of peaks in which the peak value exceeds the predetermined threshold value among the peaks of the extracted AF evaluation values is set to Nmax, and the next step S.3-5a. Proceed to 3-5c.

  Step S. 3-5c, a value obtained by adding 1 to the value of the counter N is set in the counter N, and the next step S.3. Proceed to 3-6.

  Step S. In step 3-6, step S.E. Among the Nmax AF evaluation value peaks calculated and recorded in 3-5a, the focus range of the focus lens is determined based on the Nth peak, and the focus lens is placed at a lens position within the focus range. Moving.

  The photographing focus range can be set in advance by the user, or can be automatically determined from information such as the open state of the aperture, the state of the photographing lens, and the exposure state at that time.

  In the present embodiment, photographing focus range acquisition means for automatically determining the photographing focus range from the width of the peak graph of the AF evaluation value is provided. Specifically, a graph width such as a half width of a peak graph is used.

  Step S. In step 3-7, the photographing focus range display means performs step S.3. A notice display of the photographing focus range determined in 3-6 is displayed on the LCD monitor 8.

  Step S. In step 3-8, it is determined whether or not the counter N is N ≦ Nmax. If N ≦ Nmax is not satisfied (N = Nmax + 1 now), step S.3 is performed. Returning to step 3-2, if N ≦ Nmax, step S.3. Proceed to 3-9.

  Step S. In 3-9, it is determined whether or not the half-pressed state of the release SW1 is held. Returning to 3-3, if the half-pressed state is maintained, the photographing standby state is maintained, and the next step S.3. Proceed to 3-10.

  Step S. In 3-10, it is determined whether or not the release SW1 is fully pressed. If it is not fully pressed, step S.E. Returning to 3-9, if the button is fully pressed, the next step S.3. Proceed to 3-11.

  Step S. In step S3-11, step S.E. The so-called focus bracket photographing is performed, in which photographing is performed a predetermined number of times or at a predetermined focal position interval while moving the focal lens within the photographing focal range determined in 3-6. Proceed to 3-12.

  Step S. In 3-12, the process ends.

<Function and effect>
Each time the release SW1 is pressed halfway during shooting, a plurality of shooting focus ranges are displayed in advance on the LCD monitor 8, and when the release SW1 is fully pressed, focus bracket shooting is performed within the shooting focus range displayed in the warning display. Since each photographed image is recorded, the half-pressing operation of the release SW1 is repeated until the photographing intention is met, and the release SW1 is fully depressed when the photographing focus range suitable for the photographing intention is selected. Focus bracket shooting can be performed within the shooting focus range.

  For this reason, since focus bracket shooting is performed in a shooting focus range that matches the shooting intention of the photographer, shooting is performed in a focused state intended by the photographer, and shooting with excellent image quality can be performed.

  Further, by performing the operations according to the inventions of claims 1 to 3 by the two-stage push release SW1, the first switch operation and the second switch operation can be continuously performed by one release SW1, The operability can be improved.

  The present invention will be described based on examples. In addition, description is abbreviate | omitted about the same or equivalent part as the above-mentioned Example, About the code | symbol of drawing, the same code | symbol shall be attached | subjected about the same or equivalent part.

  The digital camera C according to the third embodiment includes a shooting focus range acquisition unit that determines a plurality of shooting focus ranges that can be focused on the subject from data in the vicinity of the maximum value of the AF evaluation value with respect to the focus position, and the state of the shooting optical system 20 ( In particular, a depth-of-field acquisition unit that acquires depth-of-field information at each focus position from the aperture value) is provided.

  Then, a plurality of focus ranges that can be focused are determined from the local maximum value data of at least two AF evaluation values that are included in the depth of field and are close to each other, and the LCD is pressed every time the release SW1 is half-pressed during shooting. One of a plurality of shooting focus ranges is sequentially displayed on the monitor 8 in advance, and AF bracket shooting is performed within the shooting focus range being displayed when the release SW1 is fully pressed.

  The AF area selection mode of the third embodiment is similar to the AF area selection mode of the second embodiment as shown in FIGS. 9B, 9C, 10B, and 10C. The shooting focus range in focus bracket shooting is displayed on the LCD monitor 8 before the focus bracket shooting is started, so that the photographer can confirm the shooting focus range and perform focus bracket shooting.

  When the release SW1 is pressed halfway for the first time and the warning focus range for which the focus bracket shooting is performed is out of the shooting intention, the release SW1 is repeatedly pressed halfway to release the release SW1. Each time the button is half-pressed, the shooting focus range is changed and the notice display is switched (in the order of (b) → (c) in FIGS. 9 and 10). Therefore, the operation is repeated until the shooting intention is met. When the shooting focus range is selected, the release SW1 is fully pressed to perform focus bracket shooting.

  The shooting processing operation of the third embodiment is almost the same as the shooting processing operation of the second embodiment (the processing shown in the flowchart of FIG. 6), but the shooting focus range for determining the shooting focus range for performing the focus bracket shooting described above. Since the operation of the acquisition means is different and characteristic, this operation will be described with reference to FIGS.

<Operation of shooting focus range acquisition means>
FIG. 9 (a) shows a subject (FIG. 9 (b) or FIG. 9 (c)) composed of a person in the foreground at about 1 to 2 m, a person in the back about 2 to 3 m, and a building at a distance. ), The subject distance is shown on the horizontal axis, and the AF evaluation value is shown on the vertical axis, which is obtained by a hill-climbing scan before photographing.

  Immediately after the release SW1 is half-pressed for the first time, AF evaluation value data for the subject distance shown in FIG.

  Separately from this, the depth of field L is determined from information on the open state of the aperture and the state of the photographing optical system 20, and the adjacent peaks among the peaks of the AF evaluation value fall within the depth of field L. The object is extracted, and the photographing focus range is determined by the front and rear focus positions including these peaks.

  Among a plurality of peaks of the AF evaluation value with respect to the subject distance, a peak close to the depth of field depth L or less is detected, and the photographing focus range is set so as to include the half width of these peaks.

  Then, as shown in FIG. 9B, it is displayed on the LCD monitor 8 that the focus bracket photographing is performed in the range of 1 to 3 m, which is an area where two persons are within the photographing focal range.

  If this shooting focus range does not match the photographer's intention, as shown in FIG. 9C, the release SW1 is half-pressed again to bring the building within the shooting focus range from 4 m to infinity. A preview of the far focus range is displayed.

  When the release SW1 is fully pressed, focus bracket shooting is performed in the range from 4 m to infinity where the building is within the shooting focus range.

  An example different from the above-described example is shown in FIGS. 10 (a) to 10 (c).

  FIG. 10A to FIG. 10C illustrate a subject formed by a person in front of approximately 1 to 2 m, a person approximately 2 to 3 m behind, and a car in the back. In addition, the motor vehicle shown to Fig.10 (a) is located in the position of about 4-6m.

  Immediately after the release SW1 is half-pressed for the first time, AF evaluation value data for the subject distance shown in FIG.

  Apart from this, the depth of field L ′ is determined from information on the open state of the aperture and the state of the imaging optical system 20, and the adjacent peaks among the AF evaluation value peaks are within the depth of field L ′. What is included is extracted, and the photographing focus range is determined by the front and rear focus positions including these peaks.

  Then, as shown in FIG. 10B, a notice display is performed on the LCD monitor 8 as shown in the drawing to perform the photographing of 1 to 3 m, which is an area where two persons are within the photographing focal range.

  If this shooting does not match the photographer's intention, the release half-pressing operation is performed again, so that a 2-6 m shooting focus range warning display in which the person behind and the car are within the shooting focus range is displayed. Is done.

  Then, by fully pressing the release SW1, focus bracket shooting is performed in a shooting focus range of 2 to 6 m in which the back person and the car are within the shooting focus range.

  In this way, by changing the selection of the shooting focus range for shooting from information obtained by one hill-climbing scan, the shooting focus range that meets the shooting intention is displayed with as few half-presses as possible.

<Control flow chart>
FIG. 8 is a flowchart of the AF area selection mode.

  Step S. In 4-1, shooting processing in the AF area selection mode is started.

  Step S. At 4-2, the counter N is set to the initial value 0.

  Step S. In 4-3, it is determined whether or not the release SW1 is half pressed. If not half-pressed, step S.E. Return to 4-2, and if it is half-pressed, proceed to the next step (S.4-4).

  Step S. In 4-4, it is determined whether or not the value of the counter N is N> 0. If N> 0 is not satisfied (N = 0 in this case), step S. 4-5a. If N> 0, step S.4. Proceed to 4-5d.

  Step S. In 4-5a, the hill-climbing scan process is executed while shifting the focus position of the focus lens of the photographing optical system 20.

  That is, while moving the focus lens from the closest focus position to the infinity focus position, the image information is recorded, and the frequency information of the subject image (Fourier transform of the image data is performed by the AF subject frequency information acquisition unit 13a). AF evaluation value (integral value (average value) of high-frequency component of Fourier coefficient on the image plane) is calculated based on the high-frequency component information of the Fourier coefficient.

  In this embodiment, there are a plurality of subject distances that can be focused on, so there are also a plurality of AF evaluation value peaks with respect to the subject distance. In this embodiment, among the AF evaluation value peaks, the peak value Is referred to as the in-focus position with reference to the focal positions of a plurality of subjects that exceed a predetermined threshold.

  Then, the next step S.E. Proceed to 4-5b.

  Step S. 4-5b, step S.4. In 4-5a, among the extracted AF evaluation value peaks, a peak that is included in and close to the depth of field is selected, and a photographing focus range is determined based on a graph width such as a half-value width. The next step S. Proceed to 4-5c.

  Step S. In step 4-5c, step S.E. The number of shooting points of AF bracket shooting determined by the focus range acquisition process of 4-5b (the number of shooting focus ranges that can be focused) is set to Nmax, and the next step S.1. Proceed to 4-5d.

  Step S. 4-5d, a value obtained by adding 1 to the value of the counter N is set in the counter N, and the next step S.4. Proceed to 4-6.

  Step S. In step 4-6, step S.4. The focus lens is moved to a lens position within the Nth shooting focus range among the Nmax shooting focus ranges calculated and recorded in 4-5c.

  Step S. 4-7, the photographing focus range display means performs step S.4. A notice display of the photographing focus range determined in 4-6 is displayed on the LCD monitor 8.

  Step S. 4-8, it is determined whether or not the counter N is N ≦ Nmax. If N ≦ Nmax is not satisfied (N = Nmax + 1 now), step S.4 is performed. Returning to step 4-2, if N ≦ Nmax, step S. Proceed to 4-9.

  Step S. In step 4-9, it is determined whether or not the half-pressed state of the release SW1 is held. Returning to step 4-2, if the half-pressed state is maintained, the photographing standby state is maintained, and the next step S. Proceed to 4-10.

  Step S. In 4-10, it is determined whether or not the release SW1 is fully pressed. If it is not fully pressed, step S.E. Returning to 4-9, if the button is fully pressed, the next step S.4. Proceed to 4-11.

  Step S. 4-11, step S.4. The so-called focus bracket photographing is performed, in which photographing is performed at a predetermined number of times or at a predetermined focal position interval while moving the focus lens within the photographing focal range determined in 4-5b. Proceed to 4-12.

  Step S. In 4-12, the process ends.

<Function and effect>
Each time the release SW1 is pressed halfway during shooting, a plurality of shooting focus ranges are displayed in advance on the LCD monitor 8, and when the release SW1 is fully pressed, focus bracket shooting is performed within the shooting focus range displayed in the warning display. By repeating the half-pressing operation of the release SW 1 until it meets the shooting intention, and pressing the release SW 1 when the shooting focus range that matches the shooting intention is selected, the focus bracket shooting is performed within the shooting focus range at this time. Can be done.

  For this reason, since focus bracket shooting is performed in a shooting focus range that matches the shooting intention of the photographer, shooting is performed in a focused state intended by the photographer, and shooting with excellent image quality can be performed.

  In addition, since the shooting focus range is determined based on the AF evaluation value data by the focus evaluation value output unit and the depth of field information by the depth of field acquisition unit, the shooting focus range is determined without waste, and shooting is performed. With respect to a method of dealing with a shooting focus range that does not match the intention, a shooting focus range that matches the photographer's intention can be selected more quickly and appropriately.

  Further, the first switch operation and the second switch operation can be continuously performed by one release SW1 by performing the operation according to the first to third aspects of the invention by the two-push release SW1. The operability can be improved.

  Moreover, since the shooting focus range is automatically selected to include a plurality of subjects that fall within the depth of field and focus bracket shooting is performed, there is a higher possibility that the subject intended by the photographer is included. Thus, the operability is improved.

  As mentioned above, although the imaging device of the present invention has been described based on the first to third embodiments, the specific configuration is not limited to these embodiments, and is designed without departing from the gist of the present invention. Changes or additions are permitted.

  In this embodiment, the focus lock mode and the focus bracket shooting mode are switched according to whether the release SW 1 is half-pressed or fully pressed. However, switching between the focus lock mode and the focus bracket shooting mode is different. It may be performed by a switch.

  In the first to third embodiments, an example in which the imaging device of the present invention is applied to a digital camera has been shown. However, as an application field, an imaging device mounted on a mobile device such as a mobile phone with a camera or a PDA (Personal Digital Assistants). It can also be applied.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which shows the digital camera as an imaging device of this invention, (a) shows the top view of a digital camera, (b) shows the front view of a digital camera, (c) shows the rear view of a digital camera. Show. It is a block diagram which shows the structure of the internal system of the digital camera common to Example 1-Example 3. FIG. It is a flowchart figure explaining the operation | movement outline | summary of the digital camera common to Example 1- Example 3. FIG. FIG. 5 is a flowchart illustrating an AF area confirmation mode of the digital camera according to the first embodiment. 2A and 2B are conceptual diagrams for explaining an AF area confirmation mode of the digital camera according to the first embodiment. FIG. 3A is a graph of an AF evaluation value with respect to a subject distance, and FIG. FIG. 10 is a flowchart illustrating an AF area selection mode of the digital camera according to the second embodiment. FIG. 6 is a conceptual diagram illustrating an AF area selection mode of a digital camera according to a second embodiment, where (a) is a graph of AF evaluation values with respect to a subject distance, and (b) to (d) show display states of an LCD monitor. ing. (B) is the front person, (c) is the back person, and (d) is a state in which the photographing focus range is selected at the front and rear positions of the car, and these are displayed on the LCD monitor. FIG. 10 is a flowchart for explaining an AF area selection mode of the digital camera according to the third embodiment. FIG. 10 is a conceptual diagram illustrating an AF area selection mode of a digital camera according to a third embodiment, where (a) is a graph of AF evaluation values with respect to a subject distance, and (b) and (c) are display states of an LCD monitor. ing. (B) shows the front and back positions of the front person and the back person, and (c) shows a state in which the photographing focus range is selected for the background building group and these are displayed on the LCD monitor. FIG. 10 is a conceptual diagram illustrating an AF area selection mode of a digital camera according to a third embodiment, where (a) is a graph of AF evaluation values with respect to a subject distance, and (b) and (c) are display states of an LCD monitor. ing. (B) shows the front and back positions of the front person and the back person, and (c) shows the state where the shooting focus range is selected at the front and back positions of the back person and the car, and is displayed on the LCD monitor. Yes.

Explanation of symbols

8 LCD monitor (image display part)
13a AF object frequency information acquisition means (focus evaluation value output means)
17 Image buffer memory (image recording means)
20 Imaging Optical System 24 Image Sensor 23 Optical System Drive Unit (Focus Drive Unit)
C Digital camera (photographing device)
SW1 release (first switch, second switch)

Claims (3)

A photographic optical system that forms a subject image, an image sensor that converts the subject image formed by the photographic optical system into an image signal, and at least a part of the lens provided in the photographic optical system in the optical axis direction Image recording means for recording each image data captured while moving, an image display unit for displaying the captured image data, and each lens position while moving at least a part of the lenses in the optical axis direction prior to imaging a focus evaluation value output means for outputting a focus evaluation value for evaluating the degree of focusing of the photographing for determining a plurality of photographic focal range of possible focusing on the subject from the data near the maximum of the focus evaluation value for each lens position A focal range acquisition means,
Each time the first switch is operated during shooting, the shooting focus range is sequentially displayed on the image display unit, and when the second switch is operated, a plurality of positions are changed while changing the lens position within the shooting focus range being displayed. An imaging apparatus that performs multiple imaging and records each captured image. A photographic optical system that forms a subject image, an image sensor that converts the subject image formed by the photographic optical system into an image signal, and at least a part of the lens provided in the photographic optical system in the optical axis direction Image recording means for recording each image data captured while moving, an image display unit for displaying the captured image data, and each lens position while moving at least a part of the lenses in the optical axis direction prior to imaging a focus evaluation value output means for outputting a focus evaluation value for evaluating the degree of focusing of the photographing for determining a plurality of photographic focal range of possible focusing on the subject from the data near the maximum of the focus evaluation value for each lens position A focus range acquisition unit, and a depth of field acquisition unit that acquires depth of field information at each lens position from the state of the imaging optical system,
Determining a plurality of focus ranges that can be focused from the local maximum value data of at least two focus evaluation values that are included in and close to the depth of field acquired by the depth of field acquisition means;
Each time the first switch is operated during shooting, the shooting focus range is sequentially displayed on the image display unit, and when the second switch is operated, a plurality of positions are changed while changing the lens position within the shooting focus range being displayed. An imaging apparatus that performs multiple imaging and records each captured image. To claim 1 or claim 2, characterized in that respectively correspond to the half-press operation and full press operation of the first switch of the operation and the second switch operation and a two-stage release SW1 The imaging device described.

Images