JP4564445B2 - Electronic camera and bracket shooting method - Google Patents

Description

The present invention relates to an electronic camera capable of bracket photography and a bracket photography method.

In general, even with a proper exposure, an electronic camera is called “overexposure” when the subject brightness is too high and “blackout” when the subject brightness is too low due to the dynamic range. In some cases, a gradation cannot be expressed. In particular, if a whiteout or blackout occurs in a part intended by the photographer, the photograph is not expected. In order to deal with such problems, bracket shooting that allows you to select frames without overexposure or underexposure according to the photographer's intention by continuously shooting with varying exposure amounts There are electronic cameras with functions.

As an electronic camera with such a bracket shooting function, an electronic camera that determines whether or not whiteout or blackout has occurred and repeats correction until there is no whiteout or blackout phenomenon is proposed. (Patent Document 1). Also, bracket shooting that automatically determines the direction to correct overexposure and underexposure, and uses bracket exposure to pre-determine the number of frames with a preset exposure correction value in the direction to avoid and reduce overexposure and underexposure. A possible electronic camera has been proposed (Patent Document 2).

JP2001-145018A JP2004-245923

In the electronic camera disclosed in the above-mentioned Patent Document 1, since shooting is repeated while correcting until there is no whiteout or blackout phenomenon, shooting is repeated many times, and there are many useless shootings. In addition, since the electronic camera disclosed in Patent Document 2 only shoots a predetermined number of times with a predetermined correction exposure amount, the overexposure or blackout phenomenon may not be lost, and the certainty is lacking.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electronic camera and a bracket photographing method capable of photographing brackets without causing whiteout or blackout without waste.

In order to achieve the above object, the first invention provides a multi-division photometric means for measuring light by dividing a photographing screen into a plurality of areas, and an evaluation photometric value using a plurality of photometric values obtained by the multi-division photometric means. An exposure amount calculation unit that calculates an exposure amount based on the evaluation photometric value, an imaging unit that performs a shooting operation according to the exposure amount, and an image that performs image processing on the output of the imaging unit A processing unit; a determination unit that determines a whiteout or blackout position of a photographed image; and a photometric area of the multi-division photometry unit corresponding to the whiteout or blackout position, and the specific photometry Step exposure means for performing step exposure according to the difference between the photometric value of the region and the evaluation photometric value is provided.

According to a second aspect of the invention, the stepwise exposure means includes setting means for setting an exposure step of the stepwise exposure in accordance with a difference between the photometric value of the specific photometric area and the evaluation photometric value. .

Further, the third invention is characterized in that the exposure means includes setting means for setting the number of times of the stepwise exposure in accordance with a difference between the photometric value of the specific photometric area and the evaluated photometric value.

Further, the fourth invention is characterized by having a display means for displaying the number of stage exposures set by the setting means.

Further, the fifth invention provides means for detecting whether or not whiteout or blackout has occurred in the electronic image of the subject, multi-division photometry means for measuring light by dividing the photographing screen into a plurality of areas, and the above determination When it is detected by the means that overexposure or underexposure has occurred, the exposure amount based on the evaluation photometric value from the divided photometry means, and the photometric value corresponding to the position where overexposure or underexposure occurs Bracketing photographing means for performing bracket photographing between exposure amounts based on the above.

Further, the sixth invention determines whether whiteout or blackout occurs in the electronic image. If the result of this determination is whiteout or blackout, whiteout or blackout occurs. A method for detecting the brightness of a portion and imaging with a stepwise exposure amount between an appropriate exposure amount in a normal shooting mode and an appropriate exposure amount with respect to the brightness of the portion where the overexposure or underexposure occurs. To do.

According to the present invention, it is possible to provide an electronic camera and a bracket photographing method capable of photographing brackets without causing whiteout or blackout without waste.

Hereinafter, preferred embodiments of an electronic camera according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of a digital single-lens reflex camera according to the first embodiment to which the present invention is applied, and is composed of an interchangeable lens 100 and a camera body 200. 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. .

Inside the interchangeable lens 100, lenses 101 and 102 for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture amount are arranged. The lens 101 and the lens 102 are driven by a lens driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109. In the interchangeable lens 100, a lens data ROM 105 that stores information unique to the interchangeable lens such as focal length and aperture value information is arranged. These lens data ROM 105, lens driving mechanism 107, and aperture driving mechanism 109 are each connected to a lens CPU 111, and this lens CPU 111 is connected to the camera body 200 via a communication contact 300. The lens CPU 111 controls the interchangeable lens 100. The lens CPU 111 controls the lens driving mechanism 107 to perform focusing and zoom driving, and controls the diaphragm driving mechanism 109 to perform aperture value control.

Within the camera body 200, there are a position inclined 45 degrees with respect to the optical axis of the lens in order to reflect the subject image to the observation optical system, and a position jumped up to guide the subject image to the image sensor (CCD 221 described later). A movable mirror 201 that can be rotated 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 209 for observing a subject image is disposed on the emission side (right side in FIG. 1) of the pentaprism 207, and a photometric sensor 211 is disposed on the side of the pentaprism 207 so as not to interfere with the observation of the subject image. . As will be described later, the photometric sensor 211 includes a multi-division photometric element that divides a subject image and performs photometry.

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 sub mirror 203 is rotated to a position that covers the half mirror portion. When the movable mirror 201 is at the subject image observation position, the sub mirror 203 is illustrated. In this way, the position is perpendicular to the movable mirror 201. This movable mirror 201 is driven by a mirror drive mechanism 219. A distance measuring circuit 217 including a distance measuring sensor is disposed below the sub mirror 203. This circuit is a circuit for measuring the amount of focus deviation of the subject image formed by the lenses 101 and 102. is there.

A focal plane type shutter 213 for controlling the exposure time is disposed behind the movable mirror 201. The shutter 213 is driven and controlled by a shutter drive mechanism 215. A CCD 221 serving as an image sensor is disposed behind the shutter 213, and the subject image formed by the lenses 101 and 102 is photoelectrically converted into an electrical signal. In the present embodiment, the CCD is used as the image sensor, but the present invention is not limited to this, and it goes without saying that an image sensor such as a MOS can be used.

The CCD 221 is connected to a CCD drive circuit 223, and the analog / digital conversion (AD conversion) is performed by the CCD drive circuit 223. The CCD drive circuit 223 is connected to the image processing circuit 227 via the CCD interface 225. The image processing circuit 227 performs various types of image processing such as color correction, gamma (γ) correction, and contrast correction.

The image processing circuit 227 is connected to a data bus 261 in an ASIC (Application Specific Integrated Circuit) 271. In addition to the image processing circuit 227, the data bus 261 includes a sequence controller (hereinafter referred to as “body CPU”) 229, a compression circuit 231, a FLASH MEMORY control circuit 233, an SDRAM control circuit 236, an input / output circuit 239, A communication circuit 241, a recording medium control circuit 243, a video signal output circuit 247, and a switch detection circuit 253 are connected.

The body CPU 229 connected to the data bus 261 controls the flow of the electronic camera. A compression circuit 231 connected to the data bus 261 is a circuit for compressing image data or the like stored in an SDRAM 237 described later with JPEG. Note that image compression is not limited to JPEG, and other compression methods can be applied. FLASH connected to data bus 261
The MEMORY control circuit 233 is connected to the FLASH MEMORY 235, and the FLASH MEMORY 235 stores a program for controlling the flow of the electronic camera. The body CPU 229 controls the electronic camera according to the program stored in the FLASH MEMORY 235. Do. The FLASH MEMORY 235 is an electrically rewritable nonvolatile memory. The SDRAM 237 is connected to the data bus 261 via the SDRAM control circuit 236, and the SDRAM 237 temporarily stores the image information processed by the image processing circuit 227 or the image information compressed by the compression circuit 231. It is a memory for.

The input / output circuit 239 connected to the above-described photometric sensor 211, shutter drive mechanism 215, distance measuring circuit 217, and mirror drive mechanism 219 controls input / output of data with each circuit such as the body CPU 229 via the data bus 261. . A communication circuit 241 connected to the lens CPU 111 via a communication contact is connected to the data bus 261 and exchanges data with the body CPU 229 and the like and communicates control commands. A recording medium control circuit 243 connected to the data bus 261 is connected to the recording medium 245 and controls recording of image data and the like on the recording medium 245. The recording medium 245 includes a 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). It is detachable.

The video signal output circuit 247 connected to the data bus 261 is connected to the liquid crystal monitor 251 via the liquid crystal monitor drive circuit 249. The video signal output circuit 247 is a circuit for converting the image data stored in the SDRAM 237 or the recording medium 245 into a video signal for display on the liquid crystal monitor 251. The liquid crystal monitor 251 is disposed on the back surface of the camera body 200. However, the liquid crystal monitor 251 is not limited to the back surface as long as the photographer can observe the image. Various switches 355 such as a switch for detecting the first and second strokes of the shutter release button, a zoom switch for instructing driving of the zoom lens, and a bracket mode switch for instructing a bracket mode are provided via the switch detection circuit 253. It is connected to the bus 261.

Prior to describing the operation of the electronic camera according to the first embodiment of the present invention, detection of overexposure or underexposure will be described. FIG. 2 is an example of a photograph in which whiteout occurs on the cheek and forehead of a girl to be photographed. FIG. 3 is a histogram of the photograph of FIG. 2. The horizontal axis represents the brightness of the subject, and the vertical axis represents the number of pixels. When the histogram of FIG. 3 is analyzed, it can be determined that the number of pixels on the right side of the horizontal axis corresponding to high luminance is large and whiteout has occurred.

The above-mentioned photometric sensor 211 is configured by a multi-division photometric element. In the first embodiment, as shown in FIG. The respective photometric outputs BV1 to BV49 are output to the body CPU 229 via the input / output circuit 239. These photometric outputs BV1 to BV49 correspond to each part of the subject image as shown in FIG. When the above-described histogram is analyzed, it can be determined that whiteout has occurred in the photographed image, and the region of the multi-divided element and its output can be detected from the position of the whiteout portion in the image. Yes (BV30 in the example of FIG. 6). In addition, as a method for extracting a portion where whiteout occurs most, a method for extracting a pixel corresponding to the highest luminance value, a method for extracting an area having the largest number or ratio of the number of pixels equal to or higher than a predetermined luminance value, etc. There are various methods.

The case where overexposure has occurred has been described above. However, when underexposure occurs, there are a large number of pixels corresponding to low luminance in the histogram. It is possible to select the output of the multi-segment photometry element corresponding to the portion where the collapse occurs.

Next, the operation of the first embodiment of the present invention will be described with reference to the flowcharts shown in FIGS. First, when a release button (not shown) of the various switches 255 is half-pressed by the photographer, that is, when the first release is turned on, a detection signal is transmitted from the switch detection circuit 253 to the body CPU 229, as shown in FIG. The “shooting operation” flow shown is started. When the photographing operation is started, first, the photometric values BV1 to BV49 are read from the multi-division photometric element of the photometric sensor 211 (ST11). Next, an evaluation photometric value BVa is calculated based on each photometric value, and an exposure amount EVa is calculated based on the evaluation photometric value BVa (ST13). The evaluation photometric value BVa is a value obtained by weighting a total of nine photometric values of BV17 to BV19, BV24 to BV26, and BV31 to BV33 corresponding to substantially the center of the subject image with respect to each photometric value BV1 to BV49. The exposure amount EVa is obtained by adding the ISO sensitivity corresponding value SV to the evaluation photometric value BVa. This exposure amount EVa corresponds to an exposure amount with which proper exposure can be obtained in the normal photographing mode. In calculating the exposure amount EVa, as in the first embodiment, after obtaining the evaluation photometric value BVa, the exposure value is obtained by adding the ISO sensitivity-corresponding value, and the photometric value is weighted directly to directly calculate the exposure amount EVa. Can also be requested. The calculation method for evaluation photometry is not limited to the center-weighted photometry, and can be modified according to the design concept.

Next, the body CPU 229 calculates a focus shift amount of the lenses 101 and 102 based on the output of the distance measuring circuit 217, calculates a lens drive amount based on the shift amount and unique data from the lens data ROM, and this drive amount. To the lens CPU 111, and the lens CPU 111 controls the lens driving mechanism 107 to focus the lenses 101 and 102 (ST15). Thereafter, it is determined based on the output of the switch detection circuit 253 whether or not the release button is further pressed, that is, whether or not the second release is turned on. If the second release is not turned on, the process proceeds to step ST19, where it is determined whether or not the release button is held in the first release on state. Step ST17 and step ST19 are repeated. On the other hand, when the first release is off, that is, when the photographer's hand is released from the release button, the process proceeds to step ST33, and the flow returns to the main flow (not shown) from the flow of the shooting operation of FIG.

In step ST17, when the photographer fully presses the release button and detects that the second release is turned on, the process proceeds to step ST21, and imaging is performed. In this imaging, first, the body CPU 229 calculates the aperture opening value of the aperture 103 and the shutter opening time of the shutter 213 based on the exposure amount EVa calculated in step ST13, and the aperture 103 and the shutter 213 are controlled based on this. The A photoelectric conversion signal corresponding to the subject image formed on the CCD 221 with an exposure amount determined by the diaphragm 103 and the shutter 213 is read out by the CCD driving circuit 223. In the first embodiment, the exposure amount is controlled by the control of the diaphragm 103 and the shutter 213. However, the present invention is not limited to this, and an electronic shutter provided inside an image sensor such as a CCD, or an image sensor output. This may also be done by changing the amplification factor. The read photoelectric conversion signal is AD-converted by the CCD interface 225, and the digitized image signal is subjected to the above-described various image processing by the image processing circuit 227 and then passed through the data bus 261 and the SDRAM control circuit 236. Is written to the SDRAM 237.

When the imaging in step ST21 is completed, it is determined whether or not the bracket mode is set based on the output of the switch detection circuit 253 (ST23). If the bracket mode is not selected, the process proceeds to step ST31, the image data stored in the SDRAM 237 is compressed by the JPEG method or the like in the compression circuit 231, and then the recording medium is supplied via the recording medium control circuit 243. Record to H.245.

On the other hand, when the bracket mode is selected, the process proceeds to step ST25, and it is determined based on the output of the switch detection circuit 253 whether or not it is the highlight bracket mode. This highlight bracketing mode is between the appropriate exposure amount based on the brightness value (BV value) of the multi-segment photometry element corresponding to the whiteout portion and the appropriate exposure amount EVa based on the evaluation photometric value BVa calculated in step ST13. In this mode, the bracket shooting is performed in which the exposure is changed as appropriate. If it is determined in step ST25 that the highlight bracket mode is selected, the process proceeds to step ST27 to execute “highlight bracket” shown in FIG.

If it is determined in step ST25 that the highlight bracket mode is not set, the process proceeds to step ST29 because the other shadow bracket mode is selected, and the “shadow bracket” shown in FIG. 9 is executed. Here, in the shadow bracket mode, the appropriate exposure amount based on the luminance value (BV value) of the multi-division photometric element corresponding to the blackout portion and the appropriate exposure amount EVa based on the evaluation photometric value BVa calculated in step ST13. In this mode, bracketing shooting is performed in which shooting is performed by appropriately changing the exposure amount. When the execution of the highlight bracket or the shadow bracket is completed in steps ST27 and ST29, the image data is executed on the memory card in step ST31 described above, and then the process returns to the main flow in step ST33.

Next, the flow of “highlight bracket” in step ST27 will be described with reference to FIG. First, in step ST41, a histogram is created. Here, a histogram may be created over the entire region from low luminance to high luminance as shown in FIG. 3. However, the present invention is not limited to this, and only one point of maximum luminance or only the region on the high luminance side is histogram. It is enough to create. Next, the process proceeds to step ST43, and it is determined whether or not there is an over portion, that is, a whiteout portion, based on the histogram created in step ST41. This determination method detects whether or not there is a pixel corresponding to the highest luminance value, and detects whether or not there is an area where the number of pixels equal to or higher than the predetermined luminance value is large or has a high ratio. There are various methods such as a method, and the method may be appropriately selected according to the design concept.

If it is determined that there is an over portion, there will be a whiteout portion, so when shooting in highlight bracket mode, the appropriate exposure amount based on the output of the photometric element corresponding to the over portion and the result of evaluation metering The exposure is repeated a predetermined number of times (n + 1 times including imaging in ST21 in this embodiment) between the appropriate exposure amounts based on the above. For this purpose, first, it is searched from the image data where the over-area is located (ST45). If there are a plurality of over portions, the portion corresponding to the maximum luminance is searched. Next, the over-part photometric value BVs is detected from the outputs of the multi-division photometry element of the photometry sensor 211 based on the output of the photometry element corresponding to the over part searched in step ST45 (ST47).

Next, in order to calculate the stepwise exposure amount, the difference between the evaluation photometric value BVa obtained in step ST13 and the over partial photometric value BVs obtained in step ST47 is expressed by a number n corresponding to the number of times of photography in the bracket photography mode. The divided stepwise exposure correction amount ΔEV is calculated (ST49). Next, in order to count the number of shootings, m = 1 is set (ST51), and the exposure amount EV at the time of bracket shooting is calculated (ST53). This exposure amount EV is the difference between the appropriate exposure amount EVa based on the evaluation photometric value BVa and the step exposure value ΔEV obtained in step ST49 multiplied by the step number m. When m = 1, the evaluation photometry is performed. The exposure amount is underexposure by ΔEV from the exposure amount at which proper exposure is performed. When m = 2, the exposure amount is underexposure by 2 · ΔEV, and when m = n, n.・ Underexposure by ΔEV and appropriate exposure for overexposed areas. Of course, the number of exposures n may be displayed on a display means such as the liquid crystal monitor 251.

Based on the exposure amount calculated in step ST53, imaging is performed in step ST55. The imaging here is performed in the same manner as step ST21 in FIG. 7 except that the exposure amount is different. When the imaging in step ST55 is completed, 1 is added to m for counting the number of times of shooting (ST57), and it is determined whether or not the first release is held in an on state (ST59). If not, that is, if the photographer releases his hand from the release button, the process proceeds to step ST63 and returns to step ST31 in FIG. 7 to record the image data on the recording medium 245. Therefore, if the photographer releases his hand from the release button before reaching m = n, the bracket shooting is ended even if the predetermined n + 1 bracket shooting is not performed. On the other hand, if it is determined in step ST59 that the first release is on, that is, held, the process proceeds to step ST61, where it is determined whether m has reached n. Steps ST53 to ST61 are repeated until m = n. When m reaches n, the process returns to step ST31 via step ST63. When m = n, n + 1 times of shooting are performed together with the shooting at step ST21.

Returning to step ST43, if it is determined that there is no over portion, normal bracket shooting is performed because there is no overexposed portion. First, in step ST71, 0.5 is set as a fixed value for ΔEV. Note that 0.5 can be appropriately changed in design, and can be changed by the user. Thereafter, m for counting the number of times of auto bracket shooting is initialized to 1 (ST73).

Next, the exposure amount at each stage in auto bracket shooting is calculated (ST75). In this calculation, the exposure correction amount ΔEV is added for each exposure to the appropriate exposure amount EVa based on the evaluation photometric value calculated in step ST13. When the exposure amount calculation is completed, imaging is performed based on the exposure amount in the same manner as in step ST21 in FIG. Next, as in step ST41, a histogram is created (ST79), and it is determined whether the first release is on, that is, whether the release button is held halfway down. After step ST63, image data is written to the recording medium 245 in step ST31. On the other hand, if the release button is half-pressed, it is determined in step ST83 whether or not there is an over portion based on the histogram created in step ST79, and it is determined that there is no over portion. First, 1 is added to m for counting the number of times of shooting (ST85), and the process returns to step ST75 to increase the exposure amount by 0.5 EV and continue bracket shooting.

Since the exposure amount gradually increases while repeating step ST75 to step ST83, it is finally determined in step ST83 that there is an over portion. After step ST63, the image data recording medium 245 is determined in step ST31. Is written to. As described above, in the case of the highlight bracket, when it is first determined that there is no over portion, bracket photographing is performed until the over portion occurs. For this reason, exposure can be obtained in stages from the proper exposure state to the occurrence of overexposure as a whole, and it is possible to select a photograph according to the photographing intention.

Next, the flow of “shadow bracket” in step ST29 of FIG. 7 will be described with reference to FIG. First, a histogram is created in the same manner as in step ST41 (ST91), and it is determined whether or not an under portion exists based on the created histogram (ST93). In creating the histogram, the histogram may be created over the entire region from low luminance to high luminance as shown in FIG. 3. However, the present invention is not limited to this. It is also sufficient to create a histogram only for this area.

If it is determined in step ST93 that there is an under part, a blacked-out part exists. Therefore, in shadow bracket shooting, the appropriate exposure amount based on the output of the photometric element corresponding to the under part and the result of evaluation photometry are used. The imaging is repeated a predetermined number of times (n + 1 in the present embodiment) between the appropriate exposure amounts based on them. The basic method is the same as that of the highlight bracket, but the correction direction is reversed. First, the under part is searched from the image data (ST95). When there are a plurality of under portions, a portion corresponding to the minimum luminance is searched. There are various search methods when there are a plurality of under-parts, and can be selected as appropriate. Next, based on the output of the photometric element corresponding to the under part retrieved in step ST95 from the outputs of the multi-division photometric element of the photometric sensor 211, the under part photometric value BVs of the photometric area corresponding to the under part is obtained. Detect (ST97).

Next, in order to calculate the stepwise exposure correction amount, the difference between the evaluation photometric value BVa obtained in step ST13 and the under partial photometric value BVs obtained in step ST97 is a number n corresponding to the number of times of photography in the bracket photography mode. The stepwise exposure correction amount ΔEV divided by is calculated (ST99). Thereafter, in order to count the number of times of shooting, m = 1 is set (ST101), and the exposure amount EV at the time of bracket shooting is calculated (ST103). This exposure amount EV is the difference between the exposure amount EVa that is appropriate exposure with respect to the evaluation photometric value BVa and the step exposure correction amount ΔEV obtained in step ST99 multiplied by the number of steps m, where m = 1. Is an exposure amount that is overexposed by ΔEV from the exposure amount that is appropriate exposure in evaluation photometry, and when m = 2, it is an exposure amount that is overexposed by 2 · ΔEV, and m = n In this case, overexposure is performed for n · ΔEV and appropriate exposure is applied to the under portion.

The subsequent steps ST105 to ST113 are the same as steps ST55 to ST63 in FIG. 8, and will not be described in detail. However, the exposure amount is changed by ΔEV until m for counting the number of photographing reaches n. Repeat the imaging while performing bracket shooting. When the photographer releases his hand from the release button during bracket shooting, shooting ends (from ST109 to ST113 and ST31 to the main routine).

Returning to step ST93, if it is determined that there is no under portion, normal shadow bracket shooting is performed. First, in step ST121, 0.5 is set as a fixed value for the stepwise exposure correction amount ΔEV. Note that 0.5 can be changed as appropriate as described in step ST71, and can be changed by the user. Thereafter, m for counting the number of times of auto bracket shooting is initialized to 1 (ST123).

Next, the exposure amount at each stage in auto bracket shooting is calculated (ST125). In this calculation, the stepwise exposure correction amount ΔEV is subtracted for each exposure from the appropriate exposure amount EVa based on the evaluation photometric value calculated in step ST13. Since the next steps ST127 to ST135 are substantially the same as steps ST77 to ST88 in FIG. 8, detailed description thereof will be omitted. However, the difference is that “over part?” In step ST83 of FIG. 8 whereas “under part?” In step ST133 of FIG. In the highlight bracket of FIG. 8, the exposure amount is increased stepwise in step ST75, and bracket shooting is performed until an over portion, that is, a whiteout occurs, whereas in the shadow bracket of FIG. In step ST123, the exposure amount is decreased stepwise, and bracket shooting is performed until it is determined in step ST133 that an under portion, that is, blackening has occurred. This normal shadow bracket shooting is performed until the photographer detects that the release button is released (No in ST131) or until the underexposure is detected by performing stepwise exposure. After this, the image data is recorded on the recording medium 245 through step ST113 and step ST31, the process returns to the main flow, and the auto bracket shooting is finished.

In addition, in step ST45 of the present embodiment, when there are a plurality of over portions, the portion having the highest luminance value is searched from among them, but the present invention is not limited to this. The over portion may be evaluated. The same is true even if there are a plurality of under portions in step ST95.

As described above, in the first embodiment, based on the photometric value of the photometric sensor 211 serving as the multi-division photometry means, the exposure amount that provides an appropriate exposure with respect to the photometric value of the portion where whiteout or blackout occurs. In addition, since the stepwise exposure is performed between the exposure value that is the appropriate exposure with respect to the evaluation photometric value of the photometric sensor 211, it is possible to provide a photograph with no overexposure or underexposure. In addition, since the step exposure is performed a predetermined number of times, the number of step exposures does not become infinite, which is convenient for photographing.

Next, a second embodiment of the present invention will be described. In the first embodiment, the exposure difference in the stepwise exposure is a value obtained by dividing the difference in exposure amount between the appropriate exposure amount for overexposure or blackout and the appropriate exposure amount for evaluation photometry by a predetermined number. Although the number of times could be made constant, the stepwise exposure correction amount was not constant. In the second embodiment, the exposure correction amount is made constant.

The configuration of the second embodiment is the same as that of the first embodiment, and the operation is the same as that of FIGS. 10 and 11 except that the flow of the highlight bracket and the shadow bracket shown in FIGS. Since this is the same as that of the first embodiment, only different parts will be described.

First, as in the first embodiment, when the flow of the highlight bracket shown in FIG. 10 is entered, a histogram is created as in step ST41 (ST201), and it is determined whether or not there is an over portion in the image data. Perform (ST203). If it is determined that there is an over portion, the over portion in the image data is searched (ST205), and the luminance value (BVs) of the photometric area corresponding to the over portion is detected (ST207). Up to this point, the flow is the same as in the first embodiment. Subsequently, ΔEV is set to 0.5 as an exposure correction amount (ST209). Here, the numerical value of the exposure correction amount ΔEV is a design matter, and may be changed as appropriate, or may be arbitrarily set by the photographer.

Next, the stepwise exposure count p is obtained (ST211), and the exposure count p is displayed on the liquid crystal monitor 251 or the like (ST213). As a result, the photographer can recognize the number of stage exposures during bracket shooting. Subsequently, m for counting the number of times of auto bracket shooting is initialized to 1 (ST215), and the exposure amount EV is calculated (ST217). The exposure amount EV decreases the exposure correction amount by ΔEV for each step exposure from EVa which is an appropriate exposure amount for evaluation photometry. Based on this exposure amount EV, imaging is performed in the same manner as in step ST55 of FIG. 8 (ST219). When the imaging is completed, the remaining number of exposures (p-m) is calculated and displayed (ST221). Thereafter, as in the first embodiment, 1 is added to m corresponding to the number of times of photographing (ST223), and m corresponding to the number of times of photographing is set to the stepwise exposure number p while the first release is on. Continue bracket shooting until it reaches. When the photographer releases the release button or m reaches p, the image data is recorded on the recording medium 245 in step ST31 through step ST229, the process returns to the main flow, and bracket shooting is terminated.

Returning to step ST203, if it is determined that there is no over portion, it is a normal highlight bracket mode, and the exposure amount step ΔBV is set to 0.5 as in step ST209 (ST231). Subsequently, m for counting the number of times of auto bracket shooting is initialized to 1 (ST233), and the exposure amount EV is obtained (ST235). The exposure amount EV increases the exposure correction amount by ΔEV for each step exposure with respect to the appropriate exposure EVa based on the evaluation value of the multi-segment photometry of the photometric sensor 211. Based on this exposure amount EV, imaging is performed in the same manner as ST55 (ST237). When the imaging is completed, a histogram is created again as in the first embodiment (ST239), and while the first release is on, it is determined whether or not there is an over portion based on the histogram ( ST243), bracket shooting is continued while the over portion is not generated. When the photographer releases his / her hand from the release button or an over portion occurs, the image data is recorded on the recording medium 245 in step ST31 through step ST279, and bracket shooting is terminated.

Next, when entering the shadow bracket flow shown in FIG. 11, a histogram is created as in step ST91 of FIG. 9 (ST251), and it is determined whether or not there is an under part in the image data (ST253). If it is determined that there is an under part, the under part in the image data is searched (ST255), and the brightness value (BVs value) of the photometric area corresponding to this under part is detected (ST257). Up to this point, the flow is the same as in the first embodiment. Subsequently, although ΔEV is set to 0.5 corresponding to the stepwise exposure correction amount (ST259), as in the case of the highlight bracket, this numerical value is a design matter and can be changed as appropriate. It may be set arbitrarily.

Next, as in the case of the highlight bracket, the number p of the step exposure is obtained (ST261), and this is displayed on the display means such as the liquid crystal monitor 251 (ST263). M for counting the number of times of auto bracket shooting is initialized to 1 (ST265), and the exposure amount is calculated (ST267). The exposure amount EV increases the exposure amount by ΔEV for each step exposure with respect to the appropriate exposure EVa based on the evaluation value of the multi-segment photometry of the photometric sensor 211. Subsequent steps ST269 to ST279 are the same as the highlight bracket flow (ST219 to ST229), and thus detailed description thereof is omitted. In this embodiment, the stepwise exposure correction amount ΔEV in steps ST259 and ST281 is the same value, but it is needless to say that the step exposure correction amount ΔEV may be different.

Next, returning to step ST253, if it is determined that there is no under part as a result of the analysis of the histogram, the exposure level difference ΔEV is set to 0.5 as in step ST259 (ST281). Subsequently, m for counting the number of times of auto bracket shooting is initialized to 1 (ST233), and the exposure amount EV is obtained (ST285). With respect to the appropriate exposure EVa based on the evaluation value of the multi-segment photometry of the photometric sensor 211, the exposure amount EV decreases the exposure amount by ΔEV for each step exposure. Based on this exposure amount calculation value EV, imaging is performed in the same manner as ST55 (ST287). When imaging is completed, a histogram is created again as in the first embodiment (ST289), and while the first release is on, it is determined whether or not there is an under portion based on the histogram ( ST293), bracket shooting is continued while there is an under part. When the photographer releases the release button or an under portion occurs, the image data is recorded on the recording medium 245 in step ST31 through step ST279, and the process returns to the main flow to end bracket shooting.

As described above, in the second embodiment, based on the photometric value of the photometric sensor 211, the exposure amount that is appropriate exposure for the photometric value of the portion where whiteout or blackout occurs, and the evaluation of the photometric sensor 211 Since the stepwise exposure is performed between the exposure amount appropriate for the photometric value, it is possible to reliably provide a photograph without whiteout or blackout. In addition, since the exposure difference of the step exposure is constant, it is convenient when selecting a photograph according to the photographer's intention, and how many times it is exposed when overexposure or underexposure occurs Can be displayed, which is convenient for shooting.

In the above-described embodiment, the present invention is applied to a digital single-lens reflex camera. However, the present invention is not limited to a digital single-lens reflex camera. For example, an ordinary compact digital camera, a digital camera built in a mobile phone, or the like can be used. The present invention can be applied to any electronic image recording apparatus capable of performing bracket photography. Further, in the present invention, the evaluation photometry value and the photometry value corresponding to the overexposure or underexposure portion are obtained using the multi-division photometry value from the photometry sensor 211. However, the present invention is not limited to this. The output of the element may be calculated to obtain a photometric value.

It is a block diagram which shows the whole structure of the digital camera in 1st Embodiment to which this invention is applied. This is an example of a photograph in which whiteout occurs on the cheek and forehead of the girl who is the subject of photography. It is a figure which shows the histogram of the photograph of FIG. It is a figure which shows the photometry area | region of a multi-division photometry element. FIG. 5 is a diagram in which the photometric area shown in FIG. 4 is superimposed on the photograph shown in FIG. 2. It is a figure which shows the photometry area | region where the overexposure has generate | occur | produced. It is a flowchart which shows imaging | photography operation | movement. It is a flowchart which shows operation | movement of a highlight bracket. It is a flowchart which shows operation | movement of a shadow bracket. It is a flowchart which shows operation | movement of the highlight bracket in 2nd Embodiment to which this invention is applied. It is a flowchart which shows operation | movement of the shadow bracket in 2nd Embodiment to which this invention is applied.

Explanation of symbols

100 Interchangeable lenses 101, 102 Lens 103 Aperture 211 Photometric sensor 213 Shutter 221 CCD229
Sequence controller (Body CPU)

Claims (6)

Multi-division metering means for dividing the shooting screen into a plurality of areas for metering;
An exposure metering unit that calculates an evaluation metering value using a plurality of metering values obtained by the multi-division metering unit, and calculates an exposure amount based on the evaluation metering value;
Imaging means for performing a photographing operation according to the exposure amount;
Image processing means for performing image processing on the output of the imaging means;
A determination means for determining a whiteout or blackout position of a captured image;
A step exposure unit that specifies a photometry area of the multi-division photometry unit corresponding to the overexposure or blackout position, and performs stepwise exposure according to a difference between the photometry value of the specific photometry region and the evaluation photometry value; An electronic camera comprising: 2. The electronic camera according to claim 1, wherein the stepwise exposure unit includes a setting unit that sets an exposure step of the stepwise exposure according to a difference between the photometric value of the specific photometric area and the evaluation photometric value. . 2. The electronic camera according to claim 1, wherein the stepwise exposure means includes setting means for setting the number of times of the stepwise exposure according to a difference between the photometric value of the specific photometric area and the evaluation photometric value. 4. The electronic camera according to claim 3, further comprising display means for displaying the number of stage exposures set by the setting means. Detection means for detecting whether or not whiteout or blackout occurs in the electronic image of the subject;
Multi-division metering means for dividing the shooting screen into a plurality of areas for metering;
When the detection unit detects that whiteout or blackout occurs, the exposure amount based on the evaluation photometric value from the divided photometry unit, and the whiteout or blackout occur corresponding to the position. An electronic camera comprising bracket photographing means for performing bracket photographing between exposure amounts based on photometric values. Determine whether the electronic image has whiteout or blackout,
As a result of this determination, if whiteout or blackout occurs, the brightness of the part where whiteout or blackout occurs is detected,
A bracket photographing method characterized in that an image is captured with a stepwise exposure amount between an appropriate exposure amount in a normal photographing mode and an appropriate exposure amount with respect to the brightness of a portion where whiteout or blackout occurs.