JP2009141599A - Imaging apparatus and image display method of imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of obtaining an appropriate exposure level and an image display method of the imaging apparatus, in the imaging apparatus provided with a valve photographing function or its image display method. <P>SOLUTION: The imaging apparatus comprises: an imaging part 291 for repeatedly imaging an object image in a set cycle during the execution of valve photographing; an adding operation part 292 for adding image data to past image data every time the image data is output from the imaging part 291; a luminance level determination part 295 for determining the luminance level of the image added in the adding operation part 292 and generating information based on the luminance level; and an image display part 296 for superimposing the information based on the luminance level on the image added in the adding operation part 292 and displaying them. The information based on the luminance level is the histogram of added image or a difference between the luminance level of the added image and a target luminance level or the like. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging device and an image display method of the imaging device, and more particularly to an imaging device capable of displaying a subject image according to the degree of exposure in long-time shooting such as bulb shooting and an image display method of the imaging device.

  In general, bulb photography is often used when photographing subjects such as the starry sky, fireworks, and night views. However, bulb exposure varies in the appropriate exposure time (time from shutter opening to shutter closing) depending on the object to be photographed and ambient conditions, and the photographer can determine the exposure time without looking at the finished image at his own discretion. Had to decide. Therefore, there is a problem that if the judgment is wrong, the exposure becomes insufficient and the exposure becomes excessive.

Therefore, when a photographed image can be observed in accordance with exposure during bulb photographing or the like, the exposure level can be observed in real time, and the exposure time can be easily determined. For example, Patent Document 1 discloses an imaging apparatus that takes out pixel signals from an imaging element at a predetermined time interval (for example, 1/10 second) during an imaging operation and displays sequentially added images on a liquid crystal monitor. Yes.
JP 2005-117395 A

  According to the imaging apparatus described in Patent Document 1, since the progress of exposure can be confirmed, a large failure can be prevented even in bulb photography. However, many display devices such as a liquid crystal monitor mounted on an imaging device such as a camera are small and have a drawback that it is difficult to recognize details of an image. Also, because the LCD monitor looks different depending on the brightness of the backlight and the intensity of the ambient light, it is not always appropriate to determine that the exposure is appropriate during bulb shooting. You may notice a failure.

  The present invention has been made in view of such circumstances, and provides an imaging apparatus having an appropriate exposure level and an image display method of the imaging apparatus in an imaging apparatus having a bulb photographing function or an image display method thereof. The purpose is to do.

  In order to achieve the above object, an imaging apparatus according to a first aspect of the present invention starts bulb photography in response to a first manual operation, and responds to a second manual operation following the first manual operation. In the imaging apparatus configured to end shooting, an imaging unit that repeatedly captures a subject image at a set cycle during execution of the bulb shooting, and each time image data is output from the imaging unit, the image data An addition operation unit that performs an addition operation with past image data, a determination unit that determines the luminance level of the image subjected to the addition operation by the addition operation unit, and generates information based on the luminance level; and the addition operation unit An image display unit that superimposes and displays the above information on the added image.

  An imaging apparatus according to a second aspect of the invention starts bulb photography in response to a first manual operation, and finishes bulb photography in response to a second manual operation following the first manual operation. In the imaging device, during execution of the bulb photography, an imaging unit that repeatedly captures a subject image at a set cycle, and each time image data is output from the imaging unit, the image data and past image data are An addition calculation unit that performs addition calculation, a determination unit that determines a luminance level of the image subjected to addition calculation by the addition calculation unit, and generates a histogram of the addition image; and an image that is added by the addition calculation unit An image display unit that superimposes and displays the histogram.

  An imaging apparatus according to a third aspect of the invention starts bulb photography in response to a first manual operation, and finishes bulb photography in response to a second manual operation following the first manual operation. In the imaging device, during execution of the bulb photography, an imaging unit that repeatedly captures a subject image at a set cycle, and each time image data is output from the imaging unit, the image data and past image data are An addition operation unit that performs an addition operation, a determination unit that determines a luminance level of the image subjected to the addition operation by the addition operation unit, and generates information indicating a difference between the luminance level and the target luminance level; and the addition operation unit An image display unit that superimposes and displays the above information on the image subjected to the addition operation.

  According to a fourth aspect of the present invention, there is provided an image display method for an image pickup apparatus, wherein the subject image is repeatedly output at a set cycle during the bulb shooting and the image data is output, and the latest image data is output each time the image data is output. And past image data are added, and information based on the luminance level of the added image is displayed together with the added image.

According to a fifth aspect of the present invention, in the image display method of the imaging apparatus according to the fourth aspect, the information is a histogram of the added image.
According to a sixth aspect of the present invention, in the image display method of the imaging apparatus according to the fourth aspect, the information is information representing a difference between a luminance level of the added image and a target luminance level.

  ADVANTAGE OF THE INVENTION According to this invention, in the imaging device provided with the bulb | ball imaging function, or its image display method, the imaging device and the image display method of an imaging device which can obtain an appropriate exposure level can be provided.

  Hereinafter, a preferred embodiment using a digital single lens reflex camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is an external perspective view of a digital single-lens reflex camera according to an embodiment of the present invention as seen from the back.

  This digital single-lens reflex camera is composed of a camera body 200 and an interchangeable lens 100. On the upper surface of the camera body 200, a release button 21, a shooting mode dial 22, an information setting dial 24, a strobe 50, and the like are arranged. The release button 21 has a first release switch that is turned on when the photographer is half-pressed and a second release switch that is turned on when the photographer is fully pressed. When the first release switch (hereinafter referred to as 1R) is turned on, the camera performs photographing preparation operations such as focus detection, focusing of the photographing lens, and photometry of the subject brightness, and the second release switch (hereinafter referred to as 2R). When the camera is turned on, the camera executes a photographing operation for capturing image data of the subject image based on the output of the image sensor 221 (see FIG. 2).

  The shooting mode dial 22 is an operation member configured to be rotatable. By matching a picture display or a symbol representing the shooting mode provided on the shooting mode dial 22 with an index, the program shooting mode (P) and aperture priority are set. Each shooting mode such as shooting mode (A), shutter shooting priority mode (S), manual shooting mode (M), bulb mode (B), etc. can be selected.

  The information setting dial 24 is an operation member configured to be rotatable, and a desired setting value, mode, or the like can be selected by rotating the information setting dial 24 on an information display screen or the like. When the bulb mode is set, the update time of the image display during exposure can be set. The strobe 50 is a pop-up type auxiliary lighting device. By operating an operation button (not shown), the strobe 50 pops up and can irradiate the subject.

  On the rear surface of the camera body 200, there are a liquid crystal monitor 26, a continuous / single shooting button 27, an AE lock button 28, an up cross button 30U, a down cross button 30D, a right cross button 30R, and a left cross button 30L (these buttons). The cross buttons 30U, 30D, 30R, and 30L are collectively referred to as a cross button 30), an OK button 31, a live view display button 33, an enlarge button 34, a menu button 37, and a playback button 38. . The liquid crystal monitor 26 is a display device that performs live view display, reproduces and displays a captured subject image, and displays shooting information and menus. At the time of bulb photographing, an image is displayed based on an image signal acquired by the image sensor 221 during the exposure operation. Any liquid crystal display can be used as long as it can perform these displays.

  The continuous shooting / single shooting button 27 is a continuous shooting mode in which continuous shooting is performed while the release button 21 is fully pressed, and a single shooting mode in which one frame is shot when the release button 21 is fully pressed. This is an operation member for switching. The AE lock button 28 is an operation member for fixing the photometric value. Thus, when the luminance of the object to be photographed is measured and then the AE lock button 28 is operated, the photometric value is retained even if the composition is changed, and photographing can be performed without changing the exposure level.

  The cross button 30 is an operation member for instructing the movement of the cursor in the two-dimensional direction of the X direction and the Y direction on the liquid crystal monitor 26. In addition, when reproducing and displaying the subject image recorded on the recording medium 277, It is also used to select a subject image. In addition to providing four buttons for up, down, left, and right, it is possible to replace with an operation member that can be operated in two dimensions, such as a switch that can detect the operation direction in two dimensions, such as a touch switch. It is. The OK button 31 is an operation member for confirming various items selected by the cross button 30, the control dial 24, or the like.

  The live view display button 33 is an operation button for switching from a display screen for information display or the like to a live view display, or from a live view display to a display screen for information display or the like. The live view display is a mode in which the subject image is displayed on the liquid crystal monitor 26 for observation based on the output of the image sensor 221 for recording the subject image, and the information display is set to display shooting information of the digital single lens reflex camera. Therefore, this mode is displayed on the liquid crystal monitor 26. The enlargement button 34 is an operation member for enlarging and displaying a part of the subject image on the liquid crystal monitor 26, and the enlargement position can be changed by operating the cross button 30 described above.

  The menu button 37 is an operation member for switching to a menu mode for setting various modes of the digital single-lens reflex camera. When the menu mode is selected by operating the menu button 37, a menu screen is displayed on the liquid crystal monitor 26. Is done. The menu screen has a plurality of hierarchical structures. Various items are selected with the cross-shaped button 30, and selection is determined by operating the OK button 31. The playback button 38 is an operation button for instructing the liquid crystal monitor 26 to display a subject image recorded after shooting. The image data of the subject stored in a later-described SDRAM (Synchronous Dynamic Random Access Memory) 267 and recording medium 277 in a compression mode such as JPEG is expanded and displayed.

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

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

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

  The lens driving mechanism 107 and the aperture driving mechanism 109 are each connected to a lens CPU 111, and the lens CPU 111 is connected to a communication circuit 273 of the camera body 200 via a communication contact 300. The lens CPU 111 controls the inside of the interchangeable lens 100. The lens CPU 111 controls the lens driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to perform aperture value control. Further, the lens CPU 111 transmits lens-specific information such as an open aperture value and focal length information of the interchangeable lens 100, and focal length and focal position information detected by an optical system position detection mechanism (not shown) to the camera body 200. To do.

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

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

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

  This movable mirror 201 is driven by a movable mirror drive mechanism 239. A focus detection sensor 243 is disposed below the sub mirror 203, and an output of the focus detection sensor 243 is connected to a focus detection processing circuit 245. The focus detection sensor 243 is a known phase difference AF that separates the peripheral light beam of the photographic optical system 101 into two light beams in order to measure the defocus amount of the subject image formed by the photographic optical system 101. It consists of an optical system and a pair of sensors.

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

  Between the shutter 213 and the image sensor 221, an infrared cut filter / low pass filter 217, which is an optical filter for removing an infrared light component and a high frequency component from a subject light beam, is disposed.

  The image sensor 221 is connected to the image sensor drive circuit 223, and the image sensor drive circuit 223 reads an image signal from the image sensor 221. The image sensor driving circuit 223 is connected to an ADC (Analogue Digital Converter) circuit 225 that performs analog-digital conversion of an image signal. The output of the ADC circuit 225 is connected to the dark current removal circuit 227. The dark current removal circuit 227 is a circuit for removing dark current generated in the image sensor 221 and corrects image data representing the subject image using the dark current generated in the light-shielding region around the image sensor 221. To do.

The dark current removal circuit 227 is an ASIC (Application Specific
Integrated Circuit Application Specific Integrated Circuit) 250 is connected to a data bus 252 in the circuit. The data bus 252 includes a sequence controller (hereinafter referred to as “body CPU”) 251, an image processing circuit 257, a compression / decompression circuit 259, a video signal output circuit 261, an SDRAM control circuit 265, an input / output circuit 271, and a communication circuit 273. A recording medium control circuit 275, a flash memory control circuit 279, and a switch detection circuit 283 are connected.

  The body CPU 251 connected to the data bus 252 controls the operation of this digital single lens reflex camera. The image processing circuit 257 connected to the data bus 252 is a variety of images such as digital amplification (digital gain adjustment processing) of digital image data, color correction, gamma (γ) correction, contrast correction, and live view display image generation. Perform processing. The compression / decompression circuit 259 is a circuit for compressing the image data stored in the SDRAM 267 by a compression method such as JPEG or TIFF, and decompressing the compressed image data. Note that image compression is not limited to JPEG or TIFF, and other compression methods can be applied.

  The video signal output circuit 261 is connected to the liquid crystal monitor 26 via the liquid crystal monitor drive circuit 263. The video signal output circuit 261 is a circuit for converting the image data stored in the SDRAM 267 and the recording medium 277 into a video signal for display on the liquid crystal monitor 26. As shown in FIG. 1, the liquid crystal monitor 26 is disposed on the back surface of the camera body 200. However, the liquid crystal monitor 26 is not limited to the back surface as long as the photographer can observe the image. .

  The SDRAM 267 is connected to the data bus 252 via the SDRAM control circuit 265, and the SDRAM 267 temporarily stores the image data processed by the image processing circuit 257 or the image data compressed by the compression / decompression circuit 259. This is a buffer memory.

  The input / output circuit 271 connected to the image sensor driving circuit 223, the shutter driving mechanism 237, the movable mirror driving mechanism 239, the photometry processing circuit 241, and the focus detection processing circuit 245 is connected to each of the body CPU 251 and the like via the data bus 252. Controls circuit and data input / output.

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

  The recording medium 277 can be loaded with any rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), or a memory stick (registered trademark). And is detachable from the camera body 200. In addition, the hard disk may be configured to be connectable via a communication contact.

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

  1R switch that detects the first stroke (half press) of the release button 21, 2R switch that detects the second stroke (full press), power switch, menu switch linked to the menu button 37, and linked to the shooting mode dial 22 Various switches 285 including a dial switch, a dial switch interlocked with the information setting dial 24, and various switches interlocked with other operation members are connected to the data bus 252 via the switch detection circuit 283.

  Next, a configuration related to image display during exposure in bulb photography will be described with reference to FIG. The imaging unit 291 includes an imaging element 221, an imaging element drive circuit 223, an ADC circuit 225, a dark current removal circuit 227, and the like, and outputs image data based on the image signal. An output of the imaging unit 291 is connected to an addition calculation unit 292 in the calculation control unit 297.

  The calculation control unit 297 includes an addition calculation unit 292 and a luminance level determination unit 295. In the block diagram shown in FIG. 2, the calculation control unit 297 includes a body CPU 251 and an image processing circuit 257 that control the entire digital single-lens reflex camera. Correspond. The addition operation unit 292 inputs image data from the imaging unit 291 and also inputs the previous addition image data stored in the storage area of the addition image storage unit 293, and adds both to generate a new addition image. And output to the added image storage unit 293. The added image storage unit 293 is configured by a temporary storage device such as the SDRAM 267, and has a large number of storage areas divided from the storage area A to the storage area nn. Is remembered.

  That is, the first image data is stored in the storage area A, and then when the image data is output from the imaging unit 291, the addition operation between the image data and the immediately preceding added image data stored in the storage area A The value is performed, and new added image data is stored in the storage area B. As described above, every time image data is output from the imaging unit 291, the addition image storage unit 293 performs addition calculation and sequentially stores the image data in the storage area in accordance with the control of the control unit 297. Note that when there are a lot of input image data in the storage areas A to nn, they are sequentially overwritten from the storage area in which the added image is stored first.

  In the block diagram shown in FIG. 2, the image display unit 296 corresponds to the liquid crystal monitor 26, the liquid crystal monitor drive circuit 263, and the like, and displays the added image read from the added image storage unit 293. The luminance level determination unit 295 is a determination unit that receives the addition image data calculated by the addition calculation unit 292 and generates information based on the luminance level. Information based on the brightness level generated here is output to the image display unit 296. The image display unit 296 superimposes and displays information based on the luminance level on the above-described added image. The information based on the brightness level includes a histogram of image data, a difference value from the target brightness, and the like. In the first embodiment, histogram information is generated.

  With this configuration, the calculation control unit 297 outputs image data from the imaging unit 291 at the set update time interval, and the addition calculation unit 292 stores the image data and the addition image storage unit 293. Addition operation is performed on the immediately preceding added value. In each storage area of the addition image storage unit 293, the addition value of the image data until each image data is output is sequentially stored.

  An image based on the image data stored in the added image storage unit 293 is displayed on the image display unit 296. Since the image data stored in the storage area A is the first exposure, it is an underexposed image as shown in FIG. 8A, and the image stored in the storage area B is the first image stored next. The image data of the exposure is added and becomes slightly brighter as shown in FIG. Sequentially, every time image data is accumulated, the image becomes a little brighter, the image in the storage area D becomes close to the appropriate exposure as shown in FIG. 8D, and when the accumulation of image data continues further, FIG. As a result, the image becomes overexposed.

  In addition to the added image, in the first embodiment, histogram displays 320a to 320g are superimposed and displayed on the image display unit 296, as shown in FIG. The histogram displays 320a to 320g indicate the luminance distribution of the image data, the horizontal axis indicates the luminance level, and the vertical axis indicates the number of pixels corresponding to the luminance level. When the luminance level is low as a whole, the luminance distribution is biased to the left as in the histogram displays 320a and 320b, and when the luminance level is appropriate, the luminance distribution is spread out as a whole as in the histogram display 320d. When the level is high, the luminance distribution is biased to the right as in the histogram displays 320f and 320g. The photographer can determine whether or not the exposure is appropriate from the shape of the luminance distribution of the histogram displays 320a to 320g.

  When shooting is finished, the image display unit 296 displays a list of images based on the image data stored in each storage area in a thumbnail display as shown in FIG. In the case immediately after the end of bulb shooting, the selection frame 311 shows an image corresponding to the latest shooting. The photographer moves the selection frame 311 to an image according to the photographer's intention from among the images displayed in the list by operating the cross button 30, and if the image is satisfactory, selects the image with the OK button 31. When an image is selected, the image is recorded on the recording medium 277.

  Next, details of the operation of the digital single-lens reflex camera according to the embodiment of the present invention will be described with reference to the flowcharts shown in FIGS. FIG. 4 shows a power-on reset operation by the body CPU 251 on the camera body 200 side. When a battery is loaded in the camera body 200, this flow starts, and it is determined whether the power switch of the camera body 200 is on (# 1).

  If the result of the determination is that the power switch is off, it enters a sleep state that is a state of low power consumption (# 3). In this sleep state, interrupt processing is performed only when the power switch is turned on, and processing for turning on the power switch is performed in step # 5 and subsequent steps. Until the power switch is turned on, operations other than power switch interrupt processing are stopped to prevent the power battery from being consumed. In step # 1, if the power switch is on, or if the sleep state is canceled in step # 3, power supply is started (# 5).

  Next, if there is information such as the shooting mode set by the shooting mode dial 22, the ISO sensitivity set by the information setting dial 24, the manually set shutter speed or aperture value, those shooting conditions, and lens information Reading is performed (# 7). The lens information is read from the lens CPU 111 via the communication circuit 273 such as lens-specific information such as the full aperture value and focal length information of the interchangeable lens 100. In this step, if the valve mode is set, this information is read.

  Subsequently, it is determined whether or not the valve mode is set (# 9). Since the shooting mode is read in step # 7, it is determined whether or not the bulb mode is set as the read shooting mode. As a result of the determination, if the bulb mode is not set, photometry / exposure amount calculation is performed (# 11). In this step, the subject brightness is measured by the photometric sensor 211, an exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated according to the shooting mode and shooting conditions using the exposure amount.

  If the valve mode is set as a result of the determination in step # 9, an update time (cycle for repeatedly outputting image data) is input (# 31). The input of the update time will be described later with reference to FIG. When the input of the update time is finished, the process jumps to step # 13. In the bulb mode, since the shutter 213 is opened and closed by a user operation regardless of photometry, the photometry / exposure amount calculation in step # 11 is not executed.

  Next, shooting information is displayed on the liquid crystal monitor 26 (# 13). The shooting information includes the shooting mode and shooting conditions read in step # 7, and the shutter speed and aperture value exposure control values calculated in step # 11. When the bulb mode is set as the shooting mode, as shown in FIG. 10, a valve mode display 301 and an update time display 302 are displayed on the liquid crystal monitor 26 together with other shooting information.

  Once the shooting information is displayed, it is next determined whether or not the playback switch linked to the playback button 38 is on (# 17). The reproduction mode is a mode in which image data recorded on the recording medium 277 is read and displayed on the liquid crystal monitor 26 when the reproduction button 38 is operated. If the result of determination is that the regeneration switch is on, regeneration operation is executed (# 33).

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

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

  If the result of determination in step # 21 is that the 1R switch is not on, it is determined whether or not the power switch is on as in step # 1 (# 23). If the result of determination is that the power switch is on, processing returns to step # 7 and the above operation is repeated. On the other hand, if the power switch is not on, the power supply is stopped (# 25), the process returns to step # 3, and the above-described sleep state is entered.

  Next, the update time input operation in step # 31 will be described with reference to FIG. When this subroutine is entered, it is first determined whether or not the information setting dial 24 has been operated in order to input the update time (# 45). If the result of determination is that the information setting dial 24 has not been operated, processing returns to the original routine. On the other hand, if the information setting dial 24 has been operated, the switch detection circuit 283 detects the rotation direction (# 47).

  Subsequently, it is determined whether or not the detected rotation direction is a direction for reducing the update time (# 49). As a result of the determination, if the rotation direction decreases the update time, it is determined whether or not the previous update time has reached the lower limit value (# 51). The lower limit value may be set as appropriate, but may be about 0.1 seconds, for example. If the result of determination is that the lower limit has not been reached, the update time is shortened in a predetermined step in order from the current setting state (# 53). As shown in FIG. 10, the update time is displayed as the update display 302 in the shooting information on the liquid crystal monitor 26. Each time the information setting dial 24 is rotated to shorten the update time, for example, If the current setting state is the initial value of 30 seconds, it gradually decreases in a predetermined step from FIG. 11C toward the lower limit value in FIG. This step may be appropriately determined in consideration of usability. When the update time is shortened, the original routine is restored.

  If the result of determination in step # 49 is not decreasing, it is determined whether or not the previous update time has reached the upper limit (# 55). The upper limit value may be set as appropriate. For example, the upper limit value may be 9 minutes as a time period that is not affected by the dark current. If the result of determination is that the upper limit has not been reached, the update time is extended in a predetermined step (# 57). Each time the information setting dial 24 is rotated in the direction of increasing the update time, the information setting dial 24 gradually increases in a predetermined step from the current state toward the upper limit value in FIG. When the update time extension ends, the process returns to the original routine. This update time interval is an example and can be changed as appropriate.

  Next, the photographing operation in step # 37 will be described with reference to FIG. This subroutine starts when the 1R switch is turned on. First, the photographing information displayed on the liquid crystal monitor 26 is turned off (# 61). Subsequently, a subroutine for phase difference AF control is executed (# 63). In this subroutine, the focus shift direction and the focus shift amount of the photographing optical system 101 are detected by a known phase difference AF, and the drive control of the optical system drive mechanism 107 is performed based on the focus shift direction and the focus shift amount. The system 101 is focused.

  When the phase difference AF is completed, it is determined whether or not the valve mode is set as in step # 9 (# 65). If the bulb mode is not set as a result of the determination, photometry / exposure amount calculation is performed to determine exposure control values such as shutter speed and aperture value (# 67). On the other hand, if the valve mode is set as a result of the determination, step # 67 is skipped and the process proceeds to step # 69. In the bulb mode, as described above, the opening / closing time of the shutter 213 is determined by the photographer, and photometry and exposure amount calculation are unnecessary.

  Subsequently, it is determined whether the shutter button 21 has been fully pressed, that is, whether the 2R switch is on (# 69). If the result of determination is that the 2R switch is not on, it is determined whether or not the 1R switch is on (# 87). If the result of determination is that the 1R switch is not on, the shooting operation is terminated and processing returns to the original routine. On the other hand, if the result of determination is that the 1R switch is on, processing returns to step # 69 and enters a standby state for detecting the state of the 1R switch and 2R switch.

  If the result of determination in step # 69 is that the 2R switch is turned on, the routine proceeds to step for shooting. First, the movable mirror 201 is retracted (moved to the raised position) (# 71). As a result, the subject light flux by the photographing optical system 101 is guided in the direction of the image sensor 221. Subsequently, the lens CPU 111 is instructed to perform a narrowing operation, and the narrowing operation of the diaphragm 103 is executed (# 73).

  Now that the preparation for entering the normal photographing operation or the bulb photographing operation is completed, the exposure operation is started (# 75). In the exposure, the traveling of the front curtain of the shutter 213 is started and the charge accumulation of the image sensor 221 is started. When the time corresponding to the shutter speed obtained in step # 67 or the shutter speed manually set by the photographer has elapsed, the running of the rear curtain of the shutter 213 is started and the charge accumulation of the image sensor 221 is ended.

  Here, when the bulb mode is set, the shutter 213 is opened while the release button 21 is fully pressed, and during this time, the image sensor 221 repeatedly acquires image data at update time intervals. The added image based on the image data is displayed on the liquid crystal monitor 26 while being updated. At this time, the brightness level is determined, histogram information is generated based on the brightness level, and the histogram information is superimposed on the added image and displayed. Details of this exposure operation will be described later with reference to FIG.

  When the exposure operation ends, an instruction to open the diaphragm 103 is output to the lens CPU 111, the diaphragm 103 is opened (# 77), and the movable mirror 201 is returned to the lowered position (# 79). Subsequently, as in step # 65, it is determined whether or not the valve mode is set (# 81). As a result of the determination, if the valve mode is not set, image processing is performed on the data of the normal image or the added image that is read from the image sensor 221 and temporarily stored in the SDRAM 267. Data is recorded on the recording medium 277 (# 83), and display of the image displayed on the liquid crystal monitor 26 is stopped (# 85). When the image display is stopped, the original routine is restored.

  If the result of determination in step # 81 is valve mode, a list of all added images is displayed (# 89). That is, based on the image data stored in each storage area of the added image storage unit 293, a list is displayed in thumbnail display as shown in FIG. Then, the latest image, that is, the last image taken is selected and the selection frame 311 is displayed (# 91).

  Next, it is determined whether or not the cross button 30 has been operated (# 93). If the cross button 30 has not been operated, the process jumps to step # 97. The selection frame 311 is moved to switch the selected image (# 95). Subsequently, it is determined whether or not the OK button 31 has been operated (# 97). If it has not been operated, the process returns to step # 93 to execute the above-described processing. On the other hand, if the OK button 31 has been operated, the image data of the selected image is read from the added image storage unit 293 (# 99). When the reading is finished, the process proceeds to step # 83 described above to execute the process.

  Next, the exposure operation in step # 75 will be described with reference to FIG. When this subroutine is entered, first, as in step # 9, it is determined whether or not the valve mode is set (# 101). If the valve mode is not set as a result of the determination, a normal shooting mode such as a program shooting mode is executed.

  As a normal shooting mode, first, a timer for measuring the exposure time is started (# 103), and when the shutter 213 is opened, the image sensor 221 starts imaging (# 105). That is, photoelectric conversion of the subject image formed on the image sensor 221 is performed, and signal charge accumulation is started. It is determined whether the exposure time (set time) corresponding to the shutter speed calculated in step # 67 or manually set has elapsed (# 107). As a result of the determination, when the exposure time has elapsed, the shutter 213 is closed and the imaging with the image sensor 221 is stopped (# 109).

  Subsequently, the image signal is read from the image sensor 221 (# 111), and the read image signal is temporarily stored in the SDRAM 267 (# 113). Based on the temporarily stored image signal, the captured image is displayed on the liquid crystal monitor 26 (# 115). When the captured image is displayed, the original flow is restored.

  If the valve mode is set as a result of the determination in step # 101, first, all of the storage areas A to nn of the addition image prepared in the addition image storage unit 293 are cleared (# 119). The update time manually input in # 31 is set (# 120). Subsequently, a timer for updating the display update time is started (# 121), and as in step # 105, the shutter 213 is opened and imaging is started (# 123). Subsequently, the update time measuring timer determines whether or not the update time set in step # 120 has elapsed (# 125).

  As a result of the determination, if the update time has not elapsed, it is determined whether or not the release button 21 has been fully pressed, that is, whether or not the 2R switch has been turned off (# 151). When the 2R switch is on and the update time has not elapsed, the process enters a standby state in which step # 125 and step # 151 are repeatedly determined.

  As a result of the determination in step # 125, when the update time has elapsed, similarly to step # 109 and step # 111, the imaging of the image sensor 221 is stopped while the shutter 213 is open, and the image signal is read (# 127, # 129). Subsequently, the timer for update time measurement is restarted (# 131), and the image sensor 221 is started to image (# 133).

  Next, the addition image data is read from the storage area stored immediately before in the addition image storage unit 293, and the addition operation of this image data and the image data read in step # 129 is performed (# 135). The image data of the added image obtained here is stored in a storage area adjacent to the storage area read immediately before by the added image storage unit 293 (# 137). Subsequently, the stored added image is displayed on the liquid crystal monitor 26 (# 139).

  Subsequently, the brightness level determination unit 295 creates a histogram (# 141), and as shown in FIGS. 8A to 8G, the created histogram displays 320a to 320g are superimposed on the added image to display the liquid crystal. It is displayed on the monitor 26 (# 143). The photographer determines whether or not the proper exposure has been obtained from the shapes of the graphs of the histogram displays 320a to 320g. When the histogram is superimposed and displayed, the process returns to step # 125, and the above-described steps are executed.

  If the result of determination in step # 151 is that the release button 21 has been fully pressed, that is, if it is determined that the 2R switch has been turned off, the shutter 213 is closed and imaging is stopped, as in step # 127. (# 153). That is, the exposure operation is terminated, and then the original routine is returned to.

  Thus, in the first embodiment of the present invention, every time the update time set in step # 31 (# 120) elapses (# 125 → Y), the imaging with the image sensor 221 is stopped, and the image Data is output, and an added image of this image data and the immediately previous added image stored in the storage area of the added image storage unit 293 is obtained and stored sequentially. The added image stored in each storage area is updated and displayed on the liquid crystal monitor 26 as shown in FIG. 8 every time the update time elapses. When the update time elapses for the first time, since the exposure time is short, the entire image is dark. However, every time the update time elapses, image data is cumulatively added, so that the image gradually becomes brighter.

  In the present embodiment, each time the addition image is updated, a histogram is created and displayed superimposed on the addition image. Therefore, even when it is difficult to see the added image on the liquid crystal monitor 26, the photographer can easily determine whether or not the exposure is appropriate by observing the histogram displays 320a to 320g.

  Further, in the present embodiment, when the bulb mode is set, the imaging operation is repeated at the update time interval during the bulb photographing operation, the image data obtained at this time and the past added image data are added, and this added image is calculated. Data is stored in the added image storage unit 293 independently, and can be selected from a plurality of added images after the photographing is completed. For this reason, an image with an appropriate exposure level can be obtained after photographing.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, when the added image is updated, a histogram of the added image is created. In the second embodiment, the luminance level of the added image is determined, information indicating the difference between the luminance level and the target luminance level is generated, and this information is superimposed on the added image and displayed. Yes.

  The configuration of the second embodiment is the same as the configuration of the first embodiment shown in FIGS. 1 and 2, the flowcharts shown in FIGS. 4 to 6 are also the same, and after the shooting shown in FIG. This is the same for the list display, the shooting information display shown in FIG. 10, and the update display shown in FIG. The difference is that the flowchart showing the exposure operation shown in FIG. 7 is replaced with the flowchart shown in FIG. 12, and the display at the time of bulb mode imaging shown in FIG. 8 is replaced with FIG. Further, in the block diagram shown in FIG. 3, only the information based on the luminance level generated by the luminance level determination unit 295 is different, and this difference will be mainly described. Of the steps in the flowchart shown in FIG. 12, the same steps as those in the flowchart shown in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the block diagram of FIG. 3, the luminance level determination unit 295 determines the average luminance level of the image data, and outputs the difference between the average luminance level value and the target luminance level (appropriate exposure level). As shown in FIG. 13, the image determination unit 296 superimposes and displays level indicator displays 321a to 321g indicating the difference value output from the luminance level determination unit 295 on the addition image output from the addition calculation unit 292. .

  Next, the exposure operation in the second embodiment will be described with reference to the flowchart shown in FIG. In the exposure operation in the second embodiment, step # 141 and step # 143 are replaced with step # 145 to step # 149 as shown in FIG. 12 in the flowchart of FIG. 7 showing the exposure operation in the first embodiment. Therefore, only different steps will be described.

  Once the added image is displayed in step # 139, the luminance level determination unit 295 next calculates the luminance level (# 145). Here, the average luminance level of the added image data output from the addition calculation unit 292 is obtained. Note that the brightness level can be calculated by various evaluation operations such as a simple average that simply divides the total added value of image data by the number of pixels and a center-weighted average that weights the pixel data in the center of the screen. May be performed.

  Next, a level indicator image is generated (# 147), and the generated level indicator image is superimposed on the added image (# 149). When the level indicator image is superimposed and displayed, the process returns to step # 125. The level indicator image is level indicator displays 321a to 321g as shown in FIG. 13, and includes a broken line indicating a target level (appropriate level) and a shaded portion indicating the current luminance level. It is a display image in which the difference of the current level can be grasped at a glance. Generally, if the brightness of each pixel of image data has an 8-bit resolution, the luminance level of each pixel is one of 0-255. In this case, the target level (indicated by a broken line) may be set to 140, for example. Note that the level indicator displays 321a to 321g shown in FIG. 13 are an example of this display method, and the present invention is not limited to this as long as the target value and the current luminance level or the difference value are displayed.

  As described above, in the second embodiment of the present invention, since the difference between the luminance level and the target luminance level is displayed, the photographer can know whether or not the target luminance level has been reached. The end timing can be easily determined.

  As described above, in each embodiment of the present invention, the luminance level of the added image is determined, information based on the luminance level is generated, and the information based on the luminance level is added to the added image. Since the images are superimposed and displayed, an appropriate exposure level can be easily obtained.

  In each embodiment of the present invention, a list of added images as shown in FIG. 9 is displayed after bulb photographing is completed. At this time, histogram displays 320a to 320g and level indicator displays 321a to 321g are added. The image may be displayed superimposed on the image. In each embodiment, the addition image is generated when the valve mode is set. However, when the exposure is performed for a long time, for example, when the exposure is performed for a long time, the addition image is displayed. It may be generated and displayed.

  In each embodiment, when the valve mode is set, the release button 21 is fully pressed, and the shutter is opened until the full press is released, that is, while the 2R switch is on, and the imaging operation is performed. Had gone. However, other than this method, for example, the imaging operation is started when the release button 21 is fully pressed (first release operation), and the imaging operation is continued even when the release button 21 is fully released, and again. The imaging operation may be stopped when the release button 21 is fully pressed (second release operation performed after the first release operation).

  Furthermore, in each embodiment, the update time is set manually in step # 31. However, the update time is not limited to this, and for example, when the brightness is high, the update time is shortened according to the brightness of the subject. On the contrary, when the luminance is low, it is of course possible to automatically set the update time, for example.

  Further, in each embodiment, when the exposure operation is terminated, when imaging is stopped in step # 153 (FIG. 7), the process returns to the original routine. However, at this time, since the signal charge is accumulated in the image sensor 221, the image capturing unit 291 may read this signal, generate an added image, and display the added image.

  Furthermore, in each embodiment, the image selected in steps # 97 and # 99 is read. However, the selected image is not limited to one, and a plurality of added images may be read.

Furthermore, in each embodiment, the example applied to a single-lens reflex type as a digital camera has been described. However, the present invention may be a digital camera such as a compact type other than a single-lens reflex type, and may be a mobile phone or a personal digital assistant (PDA). Personal
Of course, a camera built into Digital Assist) may be used. The present invention can be applied to any imaging apparatus capable of shooting in bulb mode or long time.

  As described above, the embodiment according to the present invention has been described. However, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope in the implementation stage. . In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete some components of all the components shown by embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is the external appearance perspective view which looked at the digital single-lens reflex camera concerning 1st Embodiment of this invention from the back. 1 is a block diagram illustrating an overall configuration of an electric system of a digital single-lens reflex camera according to a first embodiment of the present invention. FIG. 3 is a block diagram showing an extracted configuration related to imaging and display such as a bulb mode in the digital single-lens reflex camera according to the first embodiment of the present invention. It is a flowchart which shows the operation | movement of the power-on reset in 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the update time input in 1st Embodiment of this invention. It is a flowchart which shows the imaging | photography operation | movement in 1st Embodiment of this invention. It is a flowchart which shows the exposure operation | movement in 1st Embodiment of this invention. It is a figure which shows the display at the time of valve | bulb mode imaging | photography in 1st Embodiment of this invention, (a) to (g) shows the display which changes with progress of update time. It is a figure which shows the list display of the full addition image at the time of completion | finish of bulb mode imaging | photography in 1st Embodiment of this invention, (a) is a list display immediately after completion | finish of imaging | photography, (b) is a list display at the time of selection. . It is a figure which shows the imaging | photography information display of the digital single-lens reflex camera concerning 1st Embodiment of this invention. It is a figure which shows the update display of the digital single-lens reflex camera concerning 1st Embodiment of this invention, (a) to (e) shows the display of a respectively different update time. It is a flowchart which shows the exposure operation | movement in 2nd Embodiment of this invention. It is a figure which shows the display at the time of valve | bulb mode imaging | photography in 2nd Embodiment of this invention, (a) to (g) shows the display which changes with progress of update time.

Explanation of symbols

21 ... Release button, 22 ... Shooting mode dial, 24 ... Information setting dial, 26 ... LCD monitor, 27 ... Continuous / single-shot button, 28 ... AE lock button, 30 ... Cross button, 30U ... Cross button for up, 30D ... Cross button for down, 30R ... Cross button for right, 30L ... Cross button for left, 31 ... OK button, 33 ..Live view display button 34... Enlarge button 37. Menu button 38. Play button 40. Media loading lid 50. Strobe 100. Interchangeable lens 101 ... Imaging optical system, 103. Diaphragm, 107... Optical system drive mechanism, 109... Diaphragm drive mechanism, 111. 203 ... submirror, 205 ... focusin Screen, 207... Pentaprism, 211... Photometric sensor, 213... Focal plane shutter, 217... Infrared cut filter / low pass filter, 221. Circuit, 225 ... ADC circuit, 227 ... dark current elimination circuit, 237 ... shutter drive mechanism, 239 ... movable mirror drive mechanism, 241 ... photometric processing circuit, 243 ... focus detection sensor 245: focus detection processing circuit, 250: ASIC, 251 ... sequence controller (body CPU), 252 ... data bus, 257 ... image processing circuit, 259 ... compression / decompression circuit, 261 ... Video signal output circuit, 263 ... Liquid crystal monitor drive circuit, 265 ... SDRAM detection circuit, 267 ... S RAM, 271 ... I / O circuit, 273 ... communication circuit, 275 ... recording medium control circuit, 277 ... recording medium, 279 ... flash memory control circuit, 281 ... flash memory, 283 ... switch detection circuit, 285 ... various switches, 291 ... imaging unit, 292 ... addition calculation unit, 293 ... addition image storage unit, 295 ... luminance level determination unit, 296 ... Image display unit, 297 ... arithmetic control unit, 300 ... communication contact, 301 ... valve mode display, 302 ... update time display, 311 ... selection frame, 320a to 320g ... histogram Display, 321a to 321g ... Level indicator display

Claims (6)

In the imaging apparatus configured to start bulb photography in response to a first manual operation and end the bulb photography in response to a second manual operation following the first manual operation.
An imaging unit that repeatedly captures a subject image at a set period during execution of the bulb photography,
Each time image data is output from the imaging unit, an addition calculation unit that performs an addition calculation of the image data and past image data;
A determination unit that determines a luminance level of the image subjected to the addition calculation by the addition calculation unit, and generates information based on the luminance level;
An image display unit that superimposes and displays the information on the image subjected to the addition calculation by the addition calculation unit;
An image pickup apparatus comprising: In the imaging apparatus configured to start bulb photography in response to a first manual operation and end the bulb photography in response to a second manual operation following the first manual operation.
An imaging unit that repeatedly captures a subject image at a set period during execution of the bulb photography,
Each time image data is output from the imaging unit, an addition calculation unit that performs an addition calculation of the image data and past image data;
A determination unit that determines a luminance level of the image subjected to the addition calculation by the addition calculation unit and generates a histogram of the addition image;
An image display unit that superimposes and displays the histogram on the image subjected to the addition calculation by the addition calculation unit;
An image pickup apparatus comprising: In the imaging apparatus configured to start bulb photography in response to a first manual operation and end the bulb photography in response to a second manual operation following the first manual operation.
An imaging unit that repeatedly captures a subject image at a set period during execution of the bulb photography,
Each time image data is output from the imaging unit, an addition calculation unit that performs an addition calculation of the image data and past image data;
A determination unit that determines a luminance level of the image subjected to the addition calculation by the addition calculation unit and generates information indicating a difference between the luminance level and the target luminance level;
An image display unit that superimposes and displays the information on the image subjected to the addition calculation by the addition calculation unit;
An image pickup apparatus comprising:   During bulb shooting, the subject image is repeated at a set cycle and image data is output. Each time the image data is output, the latest image data and past image data are added, and the above addition is performed. An image display method for an imaging apparatus, characterized in that information based on the calculated luminance level of an image is displayed together with the added image.   5. The image display method for an imaging apparatus according to claim 4, wherein the information is a histogram of the added image.   5. The image display method for an imaging apparatus according to claim 4, wherein the information is information representing a difference between a luminance level of the added image and a target luminance level.