JP2006017854A - Imaging apparatus and flash light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that insufficiency of light quantity is caused at a periphery part in comparison with a center part because of the specificity of light distribution and the characteristic of a lens in a small flash device used for photography. <P>SOLUTION: The photometry of the inside of an image plane is performed by a photometry sensor which is divided into several, and the irradiation angle of the flash light emitting device at the time of photography is controlled on the basis of the spread of the luminance distribution of a photographic scene. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device that includes or can be equipped with a flash light emitting device, and flash photography control in the flash light emitting device.

As a technique for optimizing flash emission control during flash photography in imaging devices such as cameras and digital still cameras, the main flash emission control is performed according to the steady-state photometric value and the flash pre-emission photometric value. There has been proposed an imaging apparatus that can perform suitable flash control by performing this technique (Patent Document 1). In addition, an imaging apparatus that controls the flash irradiation angle in accordance with the focal length of the photographing lens has been proposed (Patent Document 2).
Japanese Patent Laid-Open No. 5-127215 JP-A-9-061898

  In a small flash unit used for photography, the amount of light emitted to the subject differs between the vicinity of the optical axis center of the photographic lens and the high image height away from the optical axis, compared to the vicinity of the optical axis center of the photographic lens. Thus, the amount of light decreases at a portion of the image height away from the optical axis. The photographing lens itself also has a lower light intensity in the peripheral part than in the central part of the photographing screen. For the above reasons, especially in a composition in which a uniform wall or the like is included in the entire shooting screen, the peripheral portion of the shooting screen often appears darker than the central portion when flash shooting is performed. Such a phenomenon tends to be more noticeable in the case of a digital image having a narrow reproduction range compared to a film image.

  In order to reduce the decrease in brightness at the periphery of the shooting screen, the light distribution characteristics of the flash unit should be widened in advance, but if you do so at all times, the amount of light near the center of the optical axis of the shooting lens will be reversed. This reduces the so-called guide number and shortens the effective shooting distance range of flash shooting, and is not necessarily a good measure.

  In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes a photometric unit that performs photometry with a photometric sensor that divides the interior of the screen into a plurality of areas, and a luminance value obtained by the photometric unit. Luminance distribution calculating means for calculating the degree of spread of the luminance distribution, and irradiation angle control of the light emitting unit at the time of photographing are performed based on the luminance distribution calculating means.

  An image pickup apparatus according to the present invention is an image pickup apparatus including the flash light emitting device according to claim 1 or 2, wherein a light emission amount is calculated from a luminance value obtained by the photometric means at an arbitrary timing, In accordance with an imaging command instructed at a timing later than the timing, there is a light emission amount fixed mode in which imaging is performed by causing the light emitting unit to emit light based on the light emission amount, and the irradiation angle control means Only when the light emission amount fixing mode is set, the irradiation angle control of the flash light emitting device at the time of photographing is performed based on the luminance distribution calculating means.

  In addition, the imaging apparatus of the present invention includes a first photometry unit that performs photometry with a photometric sensor in which the interior of the screen is divided into a plurality of portions in a non-emission state, a pre-emission unit that performs pre-emission of the flash emission device, and during the pre-emission Second photometric means for photometry with a photometric sensor divided into a plurality of screen interiors, a difference between the second photometric value obtained by the second photometric means and the first photometric value obtained by the first photometric means And a pre-emission component calculation means for calculating a third photometric value, and an irradiation angle control of the light emitting unit at the time of photographing based on the third photometric value.

  An image pickup apparatus according to the present invention is an image pickup apparatus provided with the flash light emitting device according to claim 5 or 6, wherein the third photometric value obtained by the pre-light emission component calculating means at an arbitrary timing. A light emission amount fixed mode in which light emission is calculated based on the light emission amount in accordance with an imaging command instructed at a timing later than the timing; The irradiation angle control means controls the irradiation angle of the flash light emitting device at the time of photographing based on the extent of the luminance distribution only when the light emission amount fixing mode is set.

  Further, the flash light emitting device of the present invention is obtained by the first photometric value obtained by the photometric sensor that divides the inside of the screen into a plurality of parts in the non-emission state and the photometric sensor that divides the inside of the screen by a plurality of parts during the pre-light emission. The irradiation angle control of the light emitting unit is performed based on the third photometric value obtained from the difference from the second photometric value.

  In addition, the imaging apparatus of the present invention includes a photometric unit that performs photometry with a photometric sensor that divides the interior of the screen into a plurality of pixels, and a luminance that calculates the extent of the luminance distribution of the object scene from the luminance value obtained by the photometric unit Distribution calculation means, and performs data communication related to the irradiation angle control of the light emitting unit during photographing based on the luminance distribution calculation means to the external flash light emitting device.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device and flash light-emitting device which prevent the fall of a guide number can be provided by changing suitably the light distribution characteristic of a flash apparatus according to a scene.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 shows mainly the arrangement of optical members as a cross-sectional view in the imaging apparatus of the present embodiment. Regarding the other drawings in the present embodiment, the same reference numerals as those in FIG.

  In the drawing, the configuration of a so-called single-lens reflex camera capable of exchanging lenses is shown, but the present invention is not limited to a single-lens reflex camera.

  In the figure, reference numeral 1 denotes a camera body which is an imaging device, 2 denotes an interchangeable lens, and 3 denotes a flash device. In the camera body 1, 10 is a mechanical shutter, 11 is a low-pass filter, 12 is an image sensor having a photoelectric conversion function such as CCD or CMOS, 13 is a semi-transparent main mirror, and 14 is a first reflection mirror. Both the mirror 13 and the reflecting mirror 14 jump up to the top during photographing. 15 is a paraxial imaging plane conjugate with the surface of the image sensor 12 by the first reflecting mirror 14, 16 is a second reflecting mirror, 17 is an infrared cut filter, 18 is a stop having two openings, 19 Is a secondary imaging lens, and 20 is a focus detection sensor. As shown in FIG. 2, the focus detection sensor 20 has a structure in which two light receiving sensor sections 20A and 20B are divided into a plurality of areas corresponding to the two openings of the diaphragm 18. Further, in addition to the light receiving sensor units 20A and 20B, a signal storage unit, a signal processing peripheral circuit, and the like are formed as an integrated circuit on the same chip. The configuration from the first reflecting mirror 14 to the focus detection sensor 20 enables focus detection by an image shift method at an arbitrary position in the photographing screen.

  Reference numeral 21 denotes a diffusive focusing plate, 22 a pentaprism, 23 an eyepiece, 24 a third reflecting mirror, 25 a condenser lens, and 26 a photometric sensor for obtaining information on the luminance of the subject. As illustrated in FIG. 3, the photometric sensor 26 has a configuration including a light receiving sensor unit divided into a plurality of grids, and has a substantially entire photographing screen as a visual field. As shown in the figure, in this example, the light receiving field is divided into 7 columns × 5 rows = 35 divisions. The light receiving units divided into 35 are referred to as PD1 to PD35. In the present embodiment, the inside of the light receiving field is divided into 35, but the size, shape, and relative arrangement of the illustrated divided areas are appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. The present invention is not limited to these examples. It is well known that in addition to the light receiving sensor part, a signal amplifying part, a signal processing peripheral circuit, and the like are formed as an integrated circuit on the same chip.

  The focus plate 21, the pentaprism 22 and the eyepiece lens 23 constitute a finder optical system. Of the light beam reflected by the main mirror 13 and diffused by the focus plate 21, a part outside the optical axis is incident on the photometric sensor 26.

  FIG. 4 is a diagram showing a corresponding positional relationship between the focus detection position in the photographing screen by the focus detection means such as the focus detection sensor 20 and the 35 photometric sensors 26 divided into 35 parts. In this embodiment, the focus detection positions in the photographing screen are three examples from S0 to S2, and the focus detection position S0 performs focus detection at a position corresponding to the light receiving unit PD18 of the photometric sensor 26. Further, as shown in the drawing, the focus detection position S1 performs focus detection at a position corresponding to the light receiving portion PD16 of the photometric sensor 26, and the focus detection position S2 is focused at a position corresponding to the light receiving portion PD20 of the photometric sensor 26. It shall be detected.

  Returning to the description of FIG. Reference numeral 27 denotes a mount portion for attaching the photographic lens, 28 denotes a contact portion for performing information communication with the photographic lens, and 29 denotes a connection portion to which the flash device is attached. In the interchangeable lens 2, reference numerals 30a to 30e denote optical lenses constituting the photographing lens, reference numeral 31 denotes a diaphragm, reference numeral 32 denotes a contact part for performing information communication with the camera body, and reference numeral 33 denotes a mount part to be attached to the camera.

  In the flash unit 3, 34 is a xenon tube, 35 is a light emitting unit comprising a reflective shade and a condenser lens, 36 is a Fresnel plate, 37 is a monitor sensor for monitoring the amount of light emitted from the xenon tube 34, and 38 is attached to the camera body 1. It is an attachment part for attaching the flash device 3.

  The light emitting unit 35 including the xenon tube 34 is moved back and forth in the direction of the arrow by a motor (not shown) or the like so that the irradiation angle of the flash light can be adjusted. In a state where the light emitting unit 35 is moved to a position close to the Fresnel plate 36, the flash light is irradiated over a wide range corresponding to the wide angle lens. On the contrary, in a state where the light emitting unit 35 is moved to a position far from the Fresnel plate 36, the flash light is irradiated to a narrow range corresponding to the telephoto lens.

  FIG. 5 is a block diagram showing a configuration example of an electric circuit of the camera body 1, the interchangeable lens 2 and the flash unit 3 embodying the present invention. In the camera main body 1, reference numeral 41 denotes a control circuit by a one-chip microcomputer having, for example, an ALU, ROM, RAM, A / D converter, timer, serial communication port (SPI), etc. therein, and performs overall control of the camera mechanism and the like. A specific control sequence of the control circuit 41 will be described later. The focus detection sensor 20 and the photometry sensor 26 are the same as those described in FIG. Output signals of the focus detection sensor 20 and the photometry sensor 26 are connected to an A / D converter input terminal of the control circuit 41.

  A shutter drive circuit 42 is connected to the output terminal of the control circuit 41 and drives the mechanical shutter 10 shown in FIG. A signal processing circuit 43 controls the image sensor 12 in accordance with an instruction from the control circuit 41, inputs an image signal output from the image sensor 12 while performing A / D conversion, performs signal processing, and obtains an image signal. Further, necessary image processing is performed on the obtained image signal.

  Reference numeral 44 denotes a storage medium such as a non-volatile memory such as a flash ROM or an optical disk, which stores captured image signals. Reference numeral 45 denotes a first motor driver, which is connected to and controlled by the output terminal of the control circuit 41 to raise and lower the main mirror 13 and the first reflecting mirror 14. Reference numeral 47 is a display unit which is composed of a liquid crystal panel or the like and displays the number of shots, date information, exposure information, and the like, and each segment is controlled to be lit according to the output signal of the control circuit 41. 48 is a flash exposure lock switch which will be described later, and 49 is a release switch. Reference numeral 28 denotes a contact portion described in FIG. 1, to which an input / output signal of a serial communication port of the control circuit 41 is connected. Reference numeral 29 denotes a flash device connection unit described in FIG. 1, to which input / output signals of the serial communication port of the control circuit 41 are also connected so that communication with the flash device 3 is possible.

  In the interchangeable lens 2, for example, 51 is a lens control circuit using a one-chip microcomputer in which an ALU, ROM, RAM, timer, serial communication port (SPI), and the like are incorporated. A second motor driver 52 is connected to and controlled by the output terminal of the lens control circuit 51 and drives a second motor 53 for performing focus adjustment. A third motor driver 54 is connected to the output terminal of the lens control circuit 51 and is controlled to drive a third motor 55 for controlling the diaphragm 31 described in FIG. Reference numeral 56 denotes a distance encoder for obtaining information relating to the amount of extension of the focus adjustment lens, that is, the subject distance, and is connected to the input terminal of the lens control circuit 51. Reference numeral 57 denotes a zoom encoder for obtaining focal length information at the time of shooting when the interchangeable lens 30 is a zoom lens, and is connected to an input terminal of the lens control circuit 51.

  When the interchangeable lens 2 is attached to the camera body 1, the contact portions 28 and 32 are connected, and the lens control circuit 51 can perform data communication with the control circuit 41 of the camera body. The lens control circuit 51 includes optical information unique to the lens necessary for the control circuit 41 of the camera body to perform focus detection and exposure calculation, information on the subject distance based on the distance encoder 56 or the zoom encoder 57, or focal length information. To the control circuit 41 of the camera body by data communication. Further, the focus adjustment information and the aperture information obtained as a result of the focus detection and exposure calculation performed by the control circuit 41 of the camera body are output from the control circuit 41 of the camera body to the lens control circuit 51 by data communication, and the lens control is performed. The circuit 51 controls the second motor driver 52 according to the focus adjustment information, and controls the third motor driver 54 according to the aperture information.

  In the flash device 3, 61 is a flash control circuit by a one-chip microcomputer having an ALU, ROM, RAM, A / D converter, timer, serial communication port (SPI), etc. built therein, and 62 is a light emission of the xenon tube 34. The boosting unit, the xenon tube 34 and the monitor sensor 37 which have the function of generating a high voltage of about 300 V required for charging and charging the high voltage are the same as those described in FIG. Reference numeral 63 denotes an irradiation angle adjusting unit including a motor and a driving circuit for adjusting the irradiation angle by moving the light emitting unit 35, and reference numeral 64 denotes an irradiation angle including an encoder for detecting whether or not the light emitting unit 35 has reached a desired position. It is a detection unit. When the flash device 3 is attached to the camera body 1, the connection portions 38 and 29 are connected, and the flash control circuit 61 can perform data communication with the control circuit 41 of the camera body. The flash control circuit 61 controls the boosting unit 62 according to the communication content from the control circuit 41 of the camera body to start and stop the light emission of the xenon tube 34, and the detected amount of the monitor sensor 37 is sent to the control circuit 41 of the camera body. Output. The irradiation angle is also controlled according to the communication content from the control circuit 41 of the camera body.

  Next, a specific operation sequence related to the present invention of the control circuit 41 of the camera body will be described with reference to the flowchart of FIG. When a power switch (not shown) is turned on and the control circuit 41 becomes operable, the process is executed from step S101 in FIG.

  In step S101, the flash control circuit 61 is communicated to operate the boosting unit 62 to instruct to charge the high voltage so that it is sufficient for flash emission.

  In step S102, communication with the lens control circuit 51 is performed to obtain current focal length information of the lens.

  In step S103, the obtained focal length information of the lens is transmitted to the flash control circuit 61 and instructed to adjust the irradiation angle. Accordingly, the flash control circuit 61 operates the irradiation angle adjusting unit 63 to move the light emitting unit 35 so that the irradiation angle is suitable for the focal length of the current lens.

  In step S104, a control signal is output to the focus detection sensor 20, and signal accumulation is performed. When the accumulation is completed, A / D conversion is performed while reading the signal accumulated in the focus detection sensor 20. Further, various necessary data corrections such as shading are performed on each read digital data.

  In step S105, lens information and the like necessary for focus detection are input from the lens control circuit 51, and the focus state of each part of the shooting screen is calculated from this and digital data obtained from the focus detection sensor 20. Further, an area to be focused in the screen is determined from S0 to S2. If there is an area designated in advance by an operation member or the like, it may be followed. The lens movement amount for focusing is calculated according to the focus state in the determined area, and the calculated lens movement amount is output to the lens control circuit 51. In accordance with this, the lens control circuit 51 outputs a signal to the second motor driver 52 so as to drive the focus adjustment lens, and drives the second motor 53. As a result, the photographing lens is brought into focus with respect to the subject.

  In step S106, A / D conversion is performed while reading the signals of the light receiving portions PD1 to PD35 divided into 35 by the photometric sensor 26, luminance information of each portion of the screen is input, and necessary lens information and the like are further input to the lens control circuit 51. The luminance information of each part of the input screen is corrected, and subject luminance information of each light receiving part is obtained. The subject luminance information of each light receiving unit is referred to as B (n). n is 1 to 35 corresponding to each of the 35 light receiving portions.

In step S107, the luminance of the entire screen is calculated by weighting the luminance information of the dividing unit corresponding to the focus detection portion from the obtained subject luminance information of each light receiving unit. Based on the brightness information of the entire screen calculated in this way, the storage time (that is, the shutter speed) and the aperture value of the image sensor 12 optimal for shooting are determined from a predetermined program diagram and displayed on the display 47. When one of the shutter speed and the aperture value is preset, the other factor that provides the optimum exposure is determined in combination with the preset value. The exposure value based on the apex value between the determined shutter speed and aperture value is referred to as EvT.
EvT = Tv + Av (Tv is the apex value of the shutter speed, Av is the apex value of the aperture value)

  In step S108, the process waits for the release switch 49 to be turned on. If it is not turned on, the process returns to step S101, and if it is turned on, the process proceeds to step S109.

  In step S109, communication with the flash control circuit 61 is instructed to perform preliminary flash emission. Accordingly, the flash control circuit 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the xenon tube 34 emits light for a predetermined preliminary light emission amount. In order to obtain the luminance information of the subject during the preliminary light emission, A / D conversion is performed while reading the signals of the respective light receiving parts PD1 to PD35 divided by the photometric sensor 26, and the preliminary light emission of each part of the screen is performed. Enter brightness information. The luminance information at the time of preliminary light emission of each light receiving unit is referred to as P (n). n is 1 to 35 corresponding to each of the 35 light receiving portions.

In step S110, since the luminance information at the time of preliminary light emission of each part of the screen obtained in step S109 is subject luminance information in a state in which the background light for the subject and the preliminary light emission of the flash are added, this is only the preliminary light emission of the flash. In order to obtain subject luminance information according to the above, in each of the light receiving parts PD1 to PD35, the subject luminance information of only the background light obtained in step S106 is subtracted from the preliminary light emission luminance information obtained in step S109. The subject luminance information based only on the preliminary light emission of the flash is referred to as F (n). n is 1 to 35 corresponding to each of the 35 light receiving portions.
F (n) = P (n) -B (n)

In step S111, an average value Fmean of F (n) is first calculated in order to calculate the variation degree (degree of spread) of the subject luminance information F (n) due to only the preliminary light emission of the flash.
Fmean = {ΣF (n)} / 35 where n = 1 to 35

Next, a variation degree D (F) of F (n) is calculated.
D (F) = {Σ (| F (n) −Fmean |)} / 35 where n = 1 to 35

  For example, in a scene where there is little change in the depth of each part in the screen, such as a scene where a person is standing with a wall-like object placed immediately after it, the subject luminance information F (n) by only preliminary light emission of each light receiving part PD1 to PD35 is the difference. There are few, and it becomes like Fig.7 (a). If the frequency distribution (histogram) of F (n) in this case is taken, it becomes a concentrated distribution with high peaks as shown in FIG. On the other hand, in a scene where the depth change of each part in the screen is large, such as a scene where a person stands relatively near in the situation where the background is far away, the subject luminance information F (n) by only preliminary light emission of each light receiving part PD1 to PD35 is the person part. The difference is large, such as small in the background and small in the background portion, as shown in FIG. If the frequency distribution (histogram) of F (n) in this case is taken, it will be a distribution in which the peaks vary low as shown in FIG.

  The variation degree D (F) calculated in this way becomes a small value when F (n) has a concentrated distribution with high peaks as shown in FIG. 7B, and is shown in FIG. 7D. As shown in the figure, when the distribution of peaks is low, the value is large. Specifically, if F (n) in the case of FIG. 7A, Fmean = 10.2 and D (F) = 0.19, and F (n) in the case of FIG. 7C. If so, Fmean = 4.69 and D (F) = 1.83.

  In step S112, it is determined whether or not the scene has a variation degree D (F) smaller than a predetermined amount. It is considered that about 0.3 to 0.5 is appropriate as the predetermined amount for discriminating the scene as illustrated in FIG.

  If the degree of variation D (F) is smaller than a predetermined amount, the process proceeds to step S113.

  In step S113, in order to correct the irradiation angle of the flash adjusted in step S103, focal length information smaller than the actual focal length information of the photographing lens is transmitted to the flash control circuit 61 and an instruction to adjust the irradiation angle is given. . In accordance with this, the flash control circuit 61 operates the irradiation angle adjustment unit 63 to move the light emitting unit 35 so that the irradiation angle corresponding to the wide-angle lens is larger than the focal length of the current lens.

  In step S114, the flash control circuit 61 is communicated to instruct the flash to perform preliminary light emission again. Accordingly, the flash control circuit 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the xenon tube 34 emits light for a predetermined preliminary light emission amount. During the preliminary light emission of each part of the screen, A / D conversion is performed while reading the signals of the light receiving parts PD1 to PD35 divided into 35 by the photometric sensor 26 in order to obtain the luminance information of the subject during the preliminary light emission. Enter brightness information. The luminance information at the time of preliminary light emission for each light receiving unit is referred to as P (n). n is 1 to 35 corresponding to each of the 35 light receiving portions.

In step S115, since the luminance information at the time of preliminary light emission of each part of the screen obtained in step S114 is subject luminance information in a state in which the background light for the subject and the preliminary light emission of the flash are added, this is only the preliminary light emission of the flash. In order to obtain subject luminance information according to the above, the subject luminance information of only the background light obtained in step S106 is subtracted from the preliminary light emission luminance information obtained in step S114 in each of the light receiving parts PD1 to PD35. The subject luminance information based only on the preliminary light emission of the flash is referred to as F (n). n is 1 to 35 corresponding to each of the 35 light receiving portions.
F (n) = P (n) -B (n)

  Note that the flash luminance is calculated once again, and the subject luminance information F (n) is calculated only by the preliminary flash emission. The flash guide number changes when the illumination angle is corrected. This is because there is an error in the quantity calculation. Therefore, when the irradiation angle is corrected, the main light emission gain is calculated in step S116 based on F (n) obtained in step S115.

  If the variation degree D (F) is not smaller than the predetermined amount in step S112, the process proceeds from step S113 to step S116 without passing through step S115. That is, since the irradiation angle is not corrected, the main light emission gain is calculated in step S116 based on F (n) obtained in step S110.

In step S116, the gain G of the main light emission for the preliminary light emission is calculated from F (n) and B (n) of the area corresponding to each area in the screen and EvT obtained in step S107.
G = log ₂ {(EvT-BG) / FG}

  Here, BG focuses the subject luminance information B (n) of each light receiving unit obtained in step S106 on the screen center region where the possibility that the main subject is likely to exist or in S0 to S2 in step S102. It is a value obtained by weighted averaging at the center of the combined region.

  Similarly, the FG sets the subject luminance information F (n) based only on the preliminary light emission of the flash to the center area of the screen where the main subject is likely to exist or the center of the focused area among S0 to S2 in step S102. This is a weighted average value.

  The numerator EvT-BG is obtained by subtracting the luminance information from the background light for the main subject from the Ev value based on the combination of the shutter speed and aperture value used for imaging. Except when using, etc., if the flash light is applied to the main subject by an amount commensurate with the subtraction result, an appropriate exposure is obtained. Since the FG of the denominator is luminance information based only on the flash preliminary light emission in the main subject area, the main object is assumed to be the background light as long as the G light amount obtained by this equation is set to a multiple of the light emission amount during the main light emission with respect to the light amount of the preliminary light emission. It shows whether the proper exposure is obtained with the total amount of flash light.

  In step S117, a control signal is output to the first motor driver 45, the first motor 46 is driven, and the main mirror 13 and the first reflection mirror 14 are flipped up. Subsequently, the aperture value information calculated in step S107 is output to the lens control circuit 51. In accordance with this information, the lens control circuit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31, and drives the third motor 55. As a result, the photographing lens is brought into a narrowed state.

  In step S118, a signal is output to the shutter drive circuit 42 to open the shutter 11. As a result, a light beam from the photographic lens is incident on the image sensor 12 and imaging is possible. The signal processing circuit 43 is instructed to set the accumulation time of the image sensor 12 according to the shutter time calculated in step S107 and to perform image capture by the image sensor 12. In addition, a flash emission instruction is given to the flash control circuit 61 in synchronization with the imaging timing. In accordance with the light emission instruction, the flash control circuit 61 causes the xenon tube 34 to perform main light emission based on the output signal of the monitor sensor 37 so that the light emission amount corresponds to the gain G calculated in step S116. As a result, imaging with flash emission is performed. When the imaging is completed, a signal is output to the shutter drive circuit 42, and the shutter 11 is set in a light shielding state. As a result, the light beam from the photographing lens with respect to the image sensor 12 is blocked.

  In step S119, information is output to the lens control circuit 51 so that the aperture 31 is opened. In accordance with this information, the lens control circuit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31, and drives the third motor 55. As a result, the photographing lens is brought into an open state. Further, a control signal is output to the first motor driver, and the first motor 44 is driven to lower the main mirror 13 and the first reflection mirror 14.

  In step S120, the captured image information is read from the image sensor 12 while performing A / D conversion, and an instruction is issued to the signal processing circuit 43 to perform necessary correction processing and interpolation processing.

  In step S121, an instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the captured image information. Specifically, in the captured image information, one screen is divided into a plurality of areas, and the white area of the subject is extracted from the color difference signal for each area. Further, the white balance adjustment is performed by correcting the gain of the red channel and the blue channel of the entire screen based on the signal of the extracted area.

In step S122, the signal processing circuit 43 is instructed to compress and convert the captured image information subjected to white balance adjustment into a recording file format and store it in the storage medium 44.
This completes a series of shooting sequences.

  As described above, according to the present embodiment, when the variation degree of the luminance of the subject is small (there is no large difference in luminance on the entire screen), the flash irradiation angle that has already been set is corrected to the wide angle side. However, by reducing the difference between the light amount in the peripheral portion of the shooting screen and the light amount in the vicinity of the center, it is possible to improve the conventional tendency that the light amount drop in the peripheral portion is conspicuous.

  In addition, the flash illumination angle is corrected to the wide-angle side only when it is estimated that the light intensity drop in the peripheral part is conspicuous (that is, when the degree of variation in luminance is small), so that the flash emission energy is wasted. Absent.

(Second Embodiment)
In the first embodiment, the sequence is described in which the release switch 49 is turned on and the flash irradiation angle is corrected after preliminary flash emission. Here, in order to correct the flash irradiation angle, a certain amount of time is required to move the light emitting unit 35 with a motor or the like. Therefore, when the subject condition for correcting the flash irradiation angle is reached in the first embodiment, the release time lag becomes long. In consideration of such a point, an embodiment in which the flash irradiation angle is corrected only in an operation in which the exposure by the flash is locked in advance before the release switch 49 is turned on can be considered. Such an embodiment will be described with reference to the flowchart of FIG. The configuration described with reference to FIGS. 1 to 5 is the same as that of the first embodiment. Note that the same step numbers as in FIG. 2 are assigned to steps that perform the same processing as in the first embodiment.

  In the present embodiment, Steps S201 to S205 and Step S206 are different from those in the first embodiment, and these processes will be described.

  In this embodiment, after the value of EVT is obtained in step S107, it is checked in step S201 whether the flash exposure lock switch 48 is turned on. The flash exposure lock switch 48 is an operation member for setting a light emission amount fixing mode. When this mode is set, the flash light emission amount (preliminary light emission in the present embodiment) is based on subject brightness at an arbitrary timing. The main light emission gain G) is calculated and stored, and based on the stored light emission amount, the main light emission at the time of imaging instructed at a later timing is performed. If the flash exposure lock switch 48 is turned on, the process proceeds to step S109, and processes from step S109 to step S116, which are the same processes as in the first embodiment, are performed. After the gain G is obtained in step S116, it waits for the release switch 49 to be turned on in step S206. If it is detected that the camera is turned on, the process proceeds to step S117 and subsequent steps so that shooting is performed.

  If the flash exposure lock switch is not turned on in step S201, the process proceeds to step S202 and waits for the release switch 49 to be turned on. If it is not turned on, the process returns to step S101. If it is turned on, the process proceeds to step S203.

  The processing in steps S203, S204, and S205 calculates the main light emission gain G0 for the preliminary light emission by the same method as the processing in steps S109, S110, and S115, and the flash main light emission amount based on the G0 calculated in step S205. Is communicated to the flash control circuit 61.

  Thereafter, the process proceeds to step S218 and the subsequent steps for photographing. Accordingly, when the release switch 49 is turned on without using the flash exposure lock switch 48, the flash irradiation angle is not corrected and the image is taken and the release time lag does not increase.

  As described above, according to the present embodiment, only when a certain light emission amount fixing mode between the time when the light emission amount at the time of main light emission is determined and before the imaging instruction is set, according to the luminance variation degree. By correcting the irradiation angle, it is possible to prevent a drop in the amount of light in the peripheral portion of the shooting screen without missing the shooting timing.

It is sectional drawing of the camera, interchangeable lens, and flash apparatus which implemented this invention. It is a figure showing the structural example of the sensor for focus detection. It is a figure showing the example of a structure of the sensor for photometry. It is a figure which shows the example of a focus detection position. It is a block diagram showing the structural example of the electric circuit of a camera, an interchangeable lens, and a flash apparatus. It is an operation | movement flowchart of the control circuit of a camera. It is explanatory drawing of a pre-reflection light level. It is an operation | movement flowchart of the control circuit of the camera in a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 2 Interchangeable lens 3 Flash apparatus 10 Mechanical shutter 12 Image sensor 20 Focus detection sensor 21 Focus plate 26 Photometric sensor 34 Xenon tube 35 Light emission part unit 37 Monitor sensor 41 Camera control circuit 43 Signal processing circuit 61 Control of flash apparatus Circuit 63 Irradiation angle adjustment unit 64 Irradiation angle detection unit

Claims (11)

A metering means for metering with a metering sensor that divides the screen into multiple parts,
Luminance distribution calculating means for calculating the extent of the luminance distribution of the object scene from the luminance value at the time of pre-light emission obtained by the photometric means;
An imaging apparatus comprising: an illumination angle control unit that performs illumination angle control of a light emitting unit during photographing based on the luminance distribution calculation unit.   The imaging apparatus according to claim 1, wherein the irradiation angle control unit widens the irradiation angle of the light emitting unit during photographing when the value obtained by the luminance distribution calculation unit exceeds a threshold value. An imaging apparatus comprising the flash light emitting device according to claim 1, wherein a light emission amount is calculated from a luminance value obtained by the photometry means at an arbitrary timing, and an instruction is given at a timing later than the timing In accordance with the imaging command that has been made, it has a light emission amount fixed mode for performing imaging by causing the light emitting unit to emit light based on the light emission amount,
The imaging apparatus according to claim 1, wherein the irradiation angle control means controls the irradiation angle of the flash light emitting device during photographing based on the luminance distribution calculation means only when the light emission amount fixing mode is set. A first photometric means for measuring light with a photometric sensor in which the interior of the screen is divided into a plurality of parts in a non-light-emitting state;
Pre-light emitting means for performing pre-light emission of the flash light emitting device;
A second photometric means for performing photometry with a photometric sensor obtained by dividing the inside of the screen during the pre-flash;
Pre-emission component computing means for computing a third photometric value from the difference between the second photometric value obtained by the second photometric means and the first photometric value obtained by the first photometric means;
An imaging apparatus comprising: an illumination angle control unit that performs illumination angle control of the light emitting unit at the time of photographing based on the third photometric value.   5. The imaging apparatus according to claim 4, wherein the illumination angle control unit performs illumination angle control of the light emitting unit based on a degree of spread of a luminance distribution of the object scene obtained from the third photometric value. .   6. The imaging apparatus according to claim 5, wherein the irradiation angle control means widens the irradiation angle of the light emitting unit at the time of photographing when a value obtained from a luminance distribution of the object field exceeds a threshold value.   7. An imaging device comprising the flash light-emitting device according to claim 5 or 6, wherein a light emission amount of the flash light-emitting device is calculated from a third photometric value obtained by the pre-light-emitting component calculating means at an arbitrary timing. And having a light emission amount fixed mode in which light emission is performed based on the light emission amount in accordance with an imaging command instructed at a timing later than the timing, and the irradiation angle control means includes the light emission amount An imaging apparatus that performs irradiation angle control of the flash light emitting device at the time of photographing based on a degree of spread of the luminance distribution only when a fixed mode is set.   From the difference between the first photometric value obtained by the photometric sensor that divides the inside of the screen into a plurality of parts in the non-light-emitting state and the second photometric value obtained by the photometric sensor that divides the inside of the screen into a plurality of parts during the pre-light emission. A flash light emitting device comprising irradiation angle control means for performing irradiation angle control of a light emitting unit based on a required third photometric value.   9. The flash according to claim 8, wherein the irradiation angle control means controls the irradiation angle of the light emitting unit based on a degree of spread of a luminance distribution of the object scene obtained from the third photometric value. Light emitting device.   9. The flash light emitting device according to claim 8, wherein the irradiation angle control means widens the irradiation angle of the light emitting unit at the time of photographing when a value obtained from the luminance distribution of the object field exceeds a threshold value. Metering means for metering with a metering sensor that divides the interior of the screen into multiple parts
Luminance distribution calculating means for calculating the extent of the luminance distribution of the object scene from the luminance value obtained by the photometric means,
An image pickup apparatus that performs data communication related to irradiation angle control of a light emitting unit at the time of photographing based on the luminance distribution calculating means to an external flash light emitting apparatus.

Images