JP2007033523A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an enlargement of a stroboscopic irradiation range in a wide side of a zoom lens and light amount increase in a tele side in a digital camera provided with stroboscopes. <P>SOLUTION: The digital camera 1 has two incorporated stroboscopes 2a and 2b. A processor of the digital camera 1 variably controls irradiation directions of the incorporated stroboscopes 2a and 2b in response to a zoom position of the zoom lens 5. When the zoom position of the zoom lens 5 is set at the wide side, the irradiation directions of the incorporated stroboscopes 2a and 2b are controlled in mutually separating directions to widen a stroboscope irradiation range. When the zoom position of the zoom lens 5 is set at the tele side, the irradiation directions of the incorporated stroboscopes 2a and 2b are controlled in mutually intersecting directions to overlay the stroboscope irradiation range so as to increase the light amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus including a plurality of strobes.

  An imaging apparatus such as a digital camera is required to have a strobe that can irradiate uniformly within the angle of view and has a large light emission amount. Zoom lenses mounted on digital cameras have a larger F number on the long focal length side (tele side) than on the short focal length side (wide side) in order to achieve miniaturization. There is a tendency for the amount of light produced to be small.

  For this reason, a strobe with a relatively small amount of light may be required on the wide side, but a strobe that can uniformly illuminate a wide angle of view is required, while a strobe that can irradiate with a sufficient amount of light is required on the tele side. become.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses that the guide number is increased by causing both the internal and external strobes to emit light as necessary.

  Patent Document 2 below discloses a zoom strobe that changes the irradiation angle of the strobe in accordance with zoom driving of the imaging lens.

  Also, in Patent Document 3 below, either the first or second strobe is emitted when the subject is farther than a predetermined distance, and both strobes are emitted when the subject is closer than the predetermined distance. It is described.

JP 2001-337373 A JP 2004-37629 A JP-A-7-104356

  However, none of the above prior arts can satisfy both the uniform irradiation within the angle of view on the wide side and the increase in the amount of light on the tele side. That is, in Patent Document 1, although the guide number can be increased, the inside of the angle of view cannot be uniformly irradiated on the wide side, and in Patent Document 2 and Patent Document 3, there is a possibility that the amount of light is insufficient. In addition to being able to uniformly illuminate the angle of view, there are few cases in which it is desirable to obtain a clearer captured image by increasing the amount of light emitted from a subject present in a specific area, particularly in a focus control distance measurement area. Absent.

  An object of the present invention is to provide an imaging apparatus capable of irradiating an appropriate amount of light with a strobe light in an appropriate range regardless of whether the angle of view when photographing a subject is wide or telephoto.

  The present invention provides an imaging optical system including a zoom lens, user operation means for setting a zoom position of the zoom lens, first and second strobes, and the zoom position set by the user operation means according to the zoom position. Strobe control means for controlling the irradiation directions of the first and second strobes, and the first and second strobe irradiation directions can be changed to intersect each other as the zoom position is set to the tele side. And a strobe control means for controlling.

  In one embodiment of the present invention, the strobe control unit is configured to separate the irradiation directions of the first and second strobes from each other when the set zoom position corresponds to the shortest focal length of the zoom lens. And the irradiation range of the first and second strobes when the set zoom position corresponds to the longest focal length of the zoom lens. Are controlled so as to cross each other to overlap the irradiation ranges of the first and second strobes, thereby increasing the amount of light. Further, in another embodiment of the present invention, the irradiation directions of the first and second strobes are controlled so that the strobe light is focused on the subject existing in the distance measuring area within the angle of view.

  According to the present invention, both the uniform irradiation within the angle of view on the wide side and the increase in the amount of light on the tele side can be achieved by adaptively changing the irradiation directions of the first and second strobes. In addition, it is possible to freely adjust the irradiation light amount of the subject portion that is important within the angle of view.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an external perspective view of a digital camera according to the present embodiment. The digital camera 1 has two built-in strobes 2a and 2b (first strobe and second strobe in the figure). The built-in flashes 2a and 2b are disposed above and below the zoom lens 5 of the digital camera 1 on the left and right sides with a predetermined distance therebetween. The built-in flashes 2a and 2b are arranged in the same horizontal plane. The built-in strobes 2a and 2b are configured such that the irradiation direction (irradiation optical axis) can be varied in a horizontal plane. The built-in flashes 2a and 2b are driven to emit light simultaneously. The configuration of the strobe is well known and mainly includes a booster circuit, a charge control circuit, a main capacitor, and a discharge tube. The booster circuit boosts the battery terminal voltage to charge the main capacitor. The charge control circuit controls charging of the main capacitor by the booster circuit. The electric charge stored in the main capacitor is supplied to the discharge tube in response to the light emission command from the digital camera 1 to emit strobe light. The digital camera 1 is configured so that an external strobe (external strobe) can be attached in addition to the built-in strobes 2a and 2b, and a hot shoe 3 is provided on the top surface of the digital camera 1 for attaching the external strobe. The hot shoe 3 has a sync contact 3a and a communication contact 3b, supplies a light emission signal from the main body of the digital camera 1 to the external strobe through the sync contact 3a, and sends other signals to the external strobe through the communication contact 3b. To supply. The digital camera 1 further includes a light receiving element 4 for photometry. The light receiving element 4 detects an electrical signal corresponding to the amount of light reflected from the subject.

  FIG. 2 shows a configuration block diagram of the digital camera 1. The CCD 20 converts the subject image formed by the zoom lens 5 into an electrical signal and outputs it. A CMOS may be used instead of the CCD as the image sensor. The zoom range of the zoom lens 5 is arbitrary, but is, for example, 25 mm to 125 mm at a 35 mm film equivalent focal length. The A / D 22 converts the analog signal from the CCD sensor 20 into a digital signal and supplies it to the processor 24.

  The light receiving element 4 receives the reflected light from the subject as described above, converts the amount of light into an electrical signal, and outputs it. The A / D 23 converts the analog signal from the light receiving element 4 into a digital signal and supplies it to the processor 24.

  The user control 25 is a button, switch, or touch switch operated by the user, and includes a power switch, a shutter button, a mode setting button, a zoom button, and the like.

  In response to the user's operation of the shutter button, the processor 24 processes the image obtained by the CCD 20 and stores it in the memory card 28 as the JPEG format or the RAW format. Image processing in the processor 24 includes white balance adjustment, edge enhancement, gamma correction, and the like. The processor 24 may generate a thumbnail image of the image obtained by the CCD 20 and store it in the memory card 28. The thumbnail image is used when the user browses by displaying the image stored in the memory card 28 on the LCD 30. The memory card 28 is composed of a flash memory or any other storage medium, and is preferably a detachable removable memory card. The processor 24 processes the image obtained by the CCD 20 and displays it on the LCD 30. The image displayed on the LCD 30 may be a low-resolution image obtained by thinning out image data obtained by the CCD 20. The processor 24 also adjusts the zoom position and focus position of the zoom lens 5 according to the operation of the zoom button by the user. The zoom position and the focus position of the zoom lens 5 are controlled by a common motor. The processor 24 further controls the shutter speed and the aperture amount according to the photometric result of the light receiving element 4, and further controls whether or not to drive the built-in strobes 2a and 2b. The processor 24 needs to emit light from the built-in strobes 2a and 2b, and can emit light from the built-in strobes 2a and 2b (a charge sufficient for light emission is already charged in the strobe capacitor). 2b is caused to emit light, and the irradiation optical axes of the built-in flashes 2a and 2b are variably set according to the zoom position set by the user control 25 at this time. The processor 24 controls the driver 10 according to the zoom position information from the user control 25 to change the irradiation optical axes of the strobes 2a and 2b.

  3 and 4 show changes in the irradiation optical axes of the built-in flashes 2a and 2b according to the zoom position. FIG. 3 is a plan view of the digital camera 1. As described above, the built-in strobes 2a and 2b are configured such that their irradiation optical axes are variable (rotatable) in a horizontal plane. The angle between the irradiation optical axis 100a of the right built-in flash 2a and the optical axis 200 of the zoom lens 5 is θa (where clockwise is positive), the irradiation optical axis 100b of the left built-in flash 2b and the optical axis of the zoom lens 5 The angle formed with 200 is θb. Regarding the right built-in flash 2a, the irradiation optical axis 100a changes from the outward direction to the inward direction as the zoom position moves from the wide side to the tele side. The same applies to the left built-in flash 2b, and the irradiation optical axis 100b changes from the outward direction to the inward direction as the zoom position moves from the wide side to the tele side.

FIG. 4 shows the relationship between the zoom position and θa and θb. When the zoom position is at the shortest focal length fmin of the zoom lens 5, θa is a positive value, that is, the irradiation optical axis 100 a faces away from the optical axis 200 of the zoom lens 5. On the other hand, θb is a negative value, that is, the irradiation optical axis 100b is also directed away from the optical axis 200 of the zoom lens 5. As a result, at the zoom position fmin on the wide side, both the built-in strobes 2a and 2b are directed in opposite directions, and the strobe irradiation range including the two strobes 2a and 2b is expanded. This means that the strobe light can be uniformly applied to the angle of view on the wide side. When the zoom position moves from fmin to the tele side, θa gradually decreases, eventually becomes 0 at the zoom position, and then becomes a negative value. On the other hand, θb gradually increases and eventually becomes 0 at a zoom position, and then becomes a positive value. When the zoom position is at the longest focal length fmax of the zoom lens 5, θa is a negative value, that is, the irradiation optical axis 100 a is directed toward the optical axis 200 of the zoom lens 5. On the other hand, θb is positive, that is, the irradiation optical axis 100b is also directed toward the optical axis 200 of the zoom lens 5. As a result, at the tele zoom position fmax, both the built-in strobes 2a and 2b are directed in the same direction, the irradiation ranges of the two strobes 2a and 2b overlap, and the amount of light increases. This means that the amount of irradiation light can be increased on the tele side.
As described above, it is possible to satisfy the uniform irradiation request for the wide angle field angle on the wide side and the light quantity increase request on the tele side simultaneously.

  The processor 24 controls θa and θb according to the zoom position with a profile as shown in FIG. Specifically, the values of θa and θb with respect to the zoom position are stored in advance in a memory as a table, and θa and θb corresponding to the zoom position set by the user are read from the table and the driver 10 is controlled. The condition to be satisfied by θa and θb specified in the table is that the irradiation range of the deflected strobe light is wider than the photographing field angle and is as close to the photographing optical axis (lens optical axis) as possible. is there. For example, with respect to the zoom position fmin on the wide side, θa can be set to a large positive value and θb can be set to a large negative value, so that the irradiation range of the strobe light can be made wider than the shooting angle of view. However, the amount of light applied to the subject decreases. Therefore, it is preferable that θa and θb are close to the optical axis 200, that is, their absolute values are as small as possible.

  In FIG. 5, when the user operates the zoom switch of the user control 25 to the “tele” side to set the zoom lens 5 to the tele side, the irradiation optical axes 100a and 100b of the strobes 2a and 2b and the irradiation of the respective strobe lights. Indicates the range. In addition, the figure shows the configuration of the built-in flashes 2a and 2b and the configuration of the driver 10. The strobe 2a includes a flash light emitting tube (discharge tube) 2a-1, a reflecting mirror 2a-2, and a front panel 2a-3. The strobe light emitted from the flash tube 2a-1 is reflected by the reflecting mirror 2a-2, passes through the front panel 2a-3, and is emitted to the outside. The same applies to the built-in flash 2b. One end of the case of the built-in strobes 2a and 2b is connected to the link 10a, and the built-in strobes 2a and 2b are pivotally supported around the rotation axis in conjunction with the movement of the link 10a. The link 10a is a Y-shaped opening / closing mechanism having a bifurcated plane shape, and one of the two is connected to the built-in strobe 2a and the other is connected to the built-in strobe 2b. The link 10a opens and closes in conjunction with the movement of the push rod 10c that moves in the vertical direction in the drawing along the push rod guide 10b. When the push rod 10c moves downward along the push rod guide 10b in accordance with a control signal from the processor 24 (meaning that the push rod 10c moves to the back side of the digital camera 1), the link 10a is closed accordingly. In accordance with the operation 10a, the built-in strobe 2a rotates counterclockwise about the rotation axis, and the built-in strobe 2b rotates clockwise about the rotation axis. The push rod 10c may move in conjunction with the zoom and focus drive cam mechanism of the zoom lens 5, and the processor 24 can drive the zoom and focus drive cam mechanism of the zoom lens 5 and drive the push rod 10c. In this way, as shown in FIG. 5, the built-in strobes 2a and 2b are controlled so as to face each other in the same direction. The irradiation ranges of the built-in strobes 2a and 2b overlap each other, and the amount of light increases by adding two strobe lights at the overlapping portion. At the longest focal length fmax of the zoom lens 5, that is, at the tele end, the two optical axes 100a and 100b are set so as to intersect each other by about 1.5 degrees.

  In FIG. 6, when the user operates the zoom switch of the user control 25 to the “wide” side to set the zoom lens 5 to the wide side, the irradiation optical axes 100 a and 100 b of the strobes 2 a and 2 b and the respective strobe light irradiations. Indicates the range. When the push rod 10c moves upward in the figure along the push rod guide 10b in accordance with a control signal from the processor 24 (meaning that it moves to the front side of the digital camera 1), the link 10a opens accordingly. In accordance with the operation of the link 10a, the built-in strobe 2a rotates clockwise around the rotation axis, and the built-in strobe 2b rotates counterclockwise around the rotation axis. In this way, as shown in FIG. 6, the built-in strobes 2a and 2b are controlled to face away from each other. The irradiation range of the built-in strobes 2a and 2b is expanded, and the two strobe lights are uniformly irradiated over a wide range (especially over a wide range in the left-right direction). At the shortest focal length fmin of the zoom lens 5, that is, at the wide end, the two optical axes 100a and 100b are set to be separated from each other by about 17 degrees.

  7 and 8 show the irradiation ranges on the subject surface of the strobe light on the tele side and the wide side, respectively. The built-in strobes 2a and 2b respectively irradiate strobe light in a range of about 60 deg in the vertical direction and about 45 deg in the left-right direction. From these figures, compared with the case of emitting a single strobe, the strobe light is superimposed on a narrow range on the telephoto side to increase the amount of light (approximately 1.4 times the guide number is obtained), and wide on the wide side It will be understood that the area is illuminated with strobe light uniformly.

  FIG. 9 shows another configuration block diagram of the digital camera 1. Although FIG. 2 shows a configuration in which the digital camera 1 has a single zoom lens 5, FIG. 9 shows a configuration having two lenses 5a and 5b. The two lenses 5a and 5b are arranged on the front surface of the digital camera 1 in the vertical direction. Of the two lenses 5a and 5b, one lens may be a fixed focal length lens and the other lens may be a zoom lens, and either lens may be a zoom lens. When both lenses are zoom lenses, the zoom ranges are set to be different. For example, the lens 5a is a zoom lens with a focal length of 35 mm equivalent to 25 mm-75 mm, and the lens 5b is a zoom lens with a focal length equivalent to 35 mm film of 85 mm-200 mm.

  The first lens 5a forms an image on the first CCD sensor 20a. The first CCD sensor 20a converts the optical image into an electrical signal and outputs it to the A / D 22a. The A / D 22a converts the analog signal into a digital signal and supplies it to the processor 24. On the other hand, the second lens 5b forms an image on the second CCD sensor 20b. The second CCD sensor 20b converts the optical image into an electrical signal and outputs it to the A / D 22b. The A / D 22b converts the analog electric signal into a digital signal and supplies it to the processor 24. The processor 24 switches between the signal from the first CCD sensor 20a and the signal from the second CCD sensor 20b according to the zoom position set by the user control 25, and stores the processed image in the memory card 28. Displayed on the LCD 30.

  Also in the digital camera 1 having such a configuration, similarly to the digital camera 1 shown in FIG. 2, the processor 24 variably controls the irradiation direction of the built-in flashes 2a and 2b in accordance with the zoom position. When the first lens 5a is a fixed focal length lens of 25 mm with a 35 mm equivalent focal length or a zoom lens of 35-105 mm, the first lens is set when the zoom position set by the user control 25 is on the wide side. 5a and the first CCD 20a are selected, and the processor 24 controls the irradiation direction of the built-in flashes 2a and 2b in accordance with the zoom position of the first lens 5a. When the zoom position set by the user control 25 is on the tele side, the second lens 5b and the second CCD sensor 20b are selected, and the processor 24 sets the built-in flashes 2a and 2b according to the zoom position of the second lens 5b. Control the direction of irradiation. When the first lens 5a and the first CCD 20a are selected, the irradiation directions of the built-in strobes 2a and 2b are controlled so as to be separated from each other as shown in FIG. 6, and when the second lens 5b and the second CCD 20b are selected, The irradiation directions of the built-in flashes 2a and 2b are controlled so as to approach each other (cross each other) as shown in FIG.

  As described above, in this embodiment, in a digital camera including a plurality of imaging optical systems having different focal lengths, a high guide number can be realized while the loss of strobe light is small during zooming and the light distribution is uniform. it can. In the present embodiment, since the irradiation optical axes of the two built-in strobes 2a and 2b are controlled to be separated from each other on the wide side, the strobe is normally taken from one direction when photographing a close subject (so-called macro photography). It is possible to prevent the generation of shadows that are harmful to photographing, which occurs when irradiation is performed, and it is possible to obtain a superior photographed image. This shadow generation preventing effect becomes higher as the distance between the two built-in strobes 2a and 2b increases. In the present embodiment, the separation interval between the two built-in lenses 2a and 2b is fixed, but the separation interval may be variable.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, Other embodiment is also possible.

  For example, in FIG. 4, θa and θb change linearly with respect to the zoom position, but θa and θb may change nonlinearly with respect to the zoom position. 10 and 11 show other profiles of θa and θb. In FIG. 10, θa decreases steeply from fmin to θa = 0, that is, from the zoom position fth in the same direction as the optical axis 200, and then decreases gently to fmax. θb increases steeply up to fth and then increases gently up to fmax. In FIG. 11, θa decreases linearly from fmin to fth2, and then becomes a negative constant value until fmax. θb increases linearly from fmin to fth2, and then becomes a positive constant value until fmax. 4, 10, and 11, θa and θb have the same absolute value and opposite signs for the same zoom position.

  Further, in the present embodiment, the example in which the intersection of the strobe irradiation optical axes is arranged on the lens optical axis 200 and the control is performed so that the inside of the angle of view is uniformly irradiated when the zoom position is on the wide side. It is also possible to control so that the strobe light is concentrated at a specific position within the angle of view. For example, the digital camera 1 having a multipoint distance measuring function includes a mechanism for independently driving the irradiation optical axes of the two strobes 2a and 2b. When shooting on the wide side, the vicinity of the AF in-focus position is irradiated with two strobe light beams with priority. 12 and 13 show an example of the screen 50 displayed on the finder of the digital camera 1 or the LCD 30. FIG. In FIGS. 12 and 13, a distance measuring area 52 is shown, and focusing is performed in these areas. Therefore, the optical axes of the two strobes 2a and 2b are driven so as to irradiate these distance measurement areas within the angle of view. Alternatively, when it is known that the subject position is different within the angle of view by the multi-point distance measuring function, by directing the irradiation light of the two strobes 2a and 2b toward the subject at a longer distance, the image is apparently displayed. The inside of the corner can be irradiated uniformly. Further, at the time of preview, the user may select an area within the angle of view using the cross key or the like, and control so that the irradiation direction of the two strobes 2a and 2b is directed in that direction. FIG. 14 shows an example in which the optical axes 100a and 100b of the strobes 2a and 2b are rotated toward a specific position designated by the user within the angle of view.

  Furthermore, in the present embodiment, the case where the optical axes of the two strobes 2a and 2b are rotationally driven in the left-right direction has been described. However, the strobe light irradiation range or irradiation direction is controlled by rotationally driving in the vertical direction or the oblique direction. May be.

It is an external appearance perspective view of a digital camera. It is a block diagram of the configuration of the digital camera. It is a top view which shows the relationship between two built-in flashes and a lens optical axis (imaging optical axis). It is a graph which shows the relationship between a zoom position and (theta) a, (theta) b. It is a top view which shows the strobe irradiation direction when a zoom position is set to the tele side (tele end). It is a top view which shows the stroboscopic irradiation direction when a zoom position is set to the wide side (wide end). It is a perspective view which shows the strobe irradiation direction when a zoom position is set to the tele side (tele end). It is a perspective view which shows the strobe irradiation direction when the zoom position is set to the wide side (wide end). It is another block diagram of a digital camera. It is a graph which shows the other relationship between a zoom position and (theta) a, (theta) b. It is a graph which shows the further another relationship between a zoom position and (theta) a, (theta) b. It is a ranging area explanatory drawing within an angle of view. It is a ranging area explanatory drawing within an angle of view. It is another explanatory view of the strobe irradiation direction, and is an explanatory view when the irradiation optical axis is controlled toward an arbitrary position.

Explanation of symbols

  1 Digital camera, 2a, 2b Built-in flash, 3 Hot shoe, 4 Light receiving element, 5 Lens.

Claims (7)

An imaging optical system comprising a zoom lens;
User operation means for setting the zoom position of the zoom lens;
A first strobe and a second strobe;
Strobe control means for controlling the irradiation directions of the first and second strobes according to the zoom position set by the user operation means, wherein the first and second strobes are set as the zoom position is set to the tele side. Strobe control means for variably controlling the irradiation direction of the second strobe in a direction crossing each other;
An imaging device comprising: The apparatus of claim 1.
The strobe control means controls the first and second strobes to be separated from each other when the set zoom position corresponds to the shortest focal length of the zoom lens. When the irradiation range of the two strobes is expanded and the set zoom position corresponds to the longest focal length of the zoom lens, the irradiation directions of the first and second strobes are controlled to intersect each other. An image pickup apparatus that enlarges the light amount by overlapping the irradiation ranges of the first and second strobes. The apparatus according to claim 1,
The strobe control means includes storage means for storing a table that defines a relationship between the preset zoom position and the irradiation directions of the first and second strobes at each of the set zoom positions, An imaging apparatus that controls irradiation directions of the first and second strobes corresponding to the set zoom position by referring to a table. The device according to any one of claims 1 to 3,
The strobe control unit controls the irradiation direction of the first and second strobes so that the strobe irradiation range is wider than the shooting angle of view and close to the optical axis direction of the zoom lens. . In the device according to any one of claims 1 to 4,
The image pickup optical system has two optical systems, a first image pickup optical system having a fixed focal length lens and a second image pickup optical system having the zoom lens. In the device according to any one of claims 1 to 4,
The imaging optical system includes two optical systems each having two zoom lenses having different focal length ranges. The apparatus according to any one of claims 1 to 4, further comprising:
The strobe control means controls the irradiation direction of the first and second strobes so that the amount of light irradiated to a subject existing in a distance measuring area within an angle of view obtained by the imaging optical system increases. An imaging apparatus characterized by the above.

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