JP2005234042A - Method of controlling light emission quantity of strobe light and stroboscopic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain appropriate exposure amount by controlling the light emission quantity even at macro-photographing. <P>SOLUTION: A digital camera 2 is constituted of an imaging part 3, a stroboscopic apparatus 4, a CPU 5 and an operating part 6. The stroboscopic apparatus 4 is constituted of a strobe discharge tube 51, a light emitting capacitor 52, a charge control circuit 53, a voltage detection circuit 54, a discharge voltage adjustment circuit 55, a trigger circuit 56 and a power source 57. When a macro-photographing mode and also a strobe light emission mode are selected for the digital camera 2, the light emitting capacitor 52 is discharged by the discharge voltage adjustment circuit 55 so as to reduce the charge level of the light emitting capacitor 52. When a light emission control signal is transmitted from the CPU 5 to the trigger circuit 56, the charge voltage is already reduced in the light emitting capacitor 52, and the reduced discharge voltage flows into the strobe discharge tube 51 so as to emit the strobe light. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling a strobe light emission amount and a strobe device using the same.

  Many cameras currently used are equipped with a strobe device that emits strobe light in synchronization with shooting. In the strobe device, the strobe light emission amount is generally controlled so that the subject can be photographed with appropriate exposure while compensating for the insufficient subject luminance. The strobe light amount control described in Patent Document 1 is generally used. In the method, the flash emission is controlled so that the cumulative value of the light emission amounts by a plurality of light emissions becomes the target total light emission amount, that is, the target light amount corresponding to the subject distance.

  In the strobe device described in Patent Document 2, two capacitors having different capacities are used as strobe emission capacitors, and the amount of light emission is controlled by switching the capacitor to be used according to the subject brightness. In other words, when the subject has high brightness, discharge from the small capacity capacitor to the strobe discharge tube to emit light, and when the subject has low brightness, discharge to the strobe discharge tube with the large capacity capacitor to emit light. I have to.

  On the other hand, in recent years, digital cameras are rapidly spreading due to advantages such as low cost of solid-state imaging devices and easy photographing, but the above-described strobe device is also incorporated in this digital camera.

JP-A-5-260369 Japanese Patent Laid-Open No. 11-338019

  By the way, in a photographing optical system such as a digital camera or an inexpensive compact camera, a photographing lens having a deep depth of field is often used because of advantages such as cost and ease of design. Covers the range from macro shooting to long-distance shooting. However, in conventional strobe devices including those described in Patent Documents 1 and 2, the amount of emitted light is too large when performing macro photography, and an appropriate exposure amount cannot often be obtained. The reason why an appropriate exposure amount cannot be obtained at the time of macro photography is that, in the case of a configuration having only one strobe emission capacitor as in the strobe device described in Patent Document 1, photographing on a long distance side or low If a large-capacity capacitor is used to increase the amount of light emission in accordance with a subject with brightness, it is difficult to control the amount of light emission during macro photography, and an appropriate exposure amount cannot be obtained. In the strobe device described in Patent Document 2, a large-capacity light-emitting capacitor and a small-capacity light-emitting capacitor are switched. There is no description of controlling the amount of luminescence.

  The present invention has been made in consideration of the above circumstances, and can control the amount of light emission to achieve an appropriate exposure amount even in macro shooting with a very close subject distance, and can reach the strobe on the far side. An object of the present invention is to provide a strobe device capable of increasing the distance.

  The present invention detects a macro area from a distance measuring mechanism for detecting a subject distance in a strobe light emission amount control method for controlling a light emission amount when a strobe discharge tube is discharged by discharging a charge accumulated in a light emitting capacitor to a strobe discharge tube. In this case, after the light emitting capacitor is discharged to lower the charge level of the light emitting capacitor, the light emitting capacitor is discharged to the strobe discharge tube to emit strobe light.

  In the strobe light emission amount control method of the present invention, when a macro area is detected from a distance measuring mechanism that detects a subject distance, the light emitting capacitor is discharged to reduce the discharge current discharged to the strobe discharge tube. The light emitting capacitor is discharged to the strobe discharge tube to emit strobe light.

  The strobe light emission amount control method according to the present invention is such that the light-emitting capacitor is composed of two capacitors, and the macro discharge region is detected from only one of the capacitors when a macro area is detected from a distance measuring mechanism that detects a subject distance. When the electric field is not in the macro region, electric discharge is performed from the two capacitors to the strobe discharge tube to emit strobe light.

  Furthermore, in the strobe light emission amount control method of the present invention, the light emitting capacitor is composed of two capacitors having large and small capacities, and when the macro area is detected from a distance measuring mechanism that detects the subject distance, A discharge is performed to the strobe discharge tube, and when it is outside the macro region, the strobe discharge tube is discharged from a large-capacitance capacitor to emit strobe light.

  The strobe device of the present invention is incorporated in a camera equipped with a distance measuring mechanism for measuring a subject distance, and stores a light emitting capacitor, a charging circuit for charging the light emitting capacitor, a strobe discharge tube, and the light emitting capacitor. In a strobe device comprising a light emitting circuit that discharges the generated charge to the strobe discharge tube and emits strobe light, the charge accumulated in the light emitting capacitor is discharged to a load means other than the strobe discharge tube for the light emission. A discharge voltage adjustment circuit for reducing a charge level of the capacitor, and when the macro area is detected from the subject distance measured by the distance measuring mechanism, the charge level of the light emitting capacitor is controlled by controlling the discharge voltage adjustment circuit. After being lowered, the light emitting capacitor discharges to a strobe discharge tube to emit strobe light. To.

  The strobe device of the present invention includes a discharge current adjusting circuit that discharges the charge accumulated in the light emitting capacitor to a load means other than the strobe discharge tube to reduce a discharge current discharged to the strobe discharge tube. When the macro area is detected from the subject distance measured by the distance measuring mechanism, the discharge current adjusting circuit is controlled to reduce the discharge current discharged to the strobe discharge tube, and from the light emitting capacitor. A strobe discharge tube is discharged to emit strobe light.

  In the strobe device of the present invention, the light emitting capacitor is composed of two capacitors, and when a macro area is detected from the subject distance measured by the distance measuring mechanism, only one of the capacitors is connected to the strobe discharge tube. Capacitor selection means for discharging the stroboscopic light from the two capacitors to the stroboscopic discharge tube when they are outside the macro region is provided.

  Furthermore, in the strobe device of the present invention, the light emitting capacitor is composed of a normal light emitting capacitor and a macro light emitting capacitor having a smaller capacity than the normal light emitting capacitor, and the subject distance measured by the distance measuring mechanism is used. Capacitor switching means for discharging only the macro light emission capacitor to the strobe discharge tube when the macro region is detected, and discharging the strobe light from the normal light emission capacitor to the strobe discharge tube when not in the macro region. It is characterized by having.

  In the present invention, when the macro area is detected from the distance measuring mechanism that detects the subject distance, the light emitting capacitor is discharged to lower the charge level of the light emitting capacitor, and then the light emitting capacitor is discharged to the strobe discharge tube. Since the flash is emitted, the amount of light emitted can be controlled to achieve an appropriate exposure even during macro photography.

  Further, in the present invention, when the macro area is detected from the distance measuring mechanism for detecting the subject distance, the light emitting capacitor is discharged from the light emitting capacitor while the discharge current discharged to the strobe discharge tube is reduced. Since the discharge tube is discharged to emit strobe light, it is possible to control the light emission amount even during macro photography so as to obtain an appropriate exposure amount.

  Further, in the present invention, when the macro area is detected from the distance measuring mechanism that detects the subject distance when the light emitting capacitor is composed of two capacitors, only one of the capacitors is discharged to the strobe discharge tube. Since the strobe is discharged by discharging from two capacitors to the strobe discharge tube, the amount of light emitted is controlled to achieve an appropriate exposure amount even during macro photography, and the strobe reaches the long distance with sufficient light emission even during normal photography. The distance can also be increased.

  Furthermore, in the present invention, when the macro area is detected from the distance measuring mechanism that detects the subject distance, the light emitting capacitor is composed of two capacitors having large and small capacities, and the macro capacitor is discharged from the small capacitor to the strobe discharge tube. When not in the area, the flash discharges from the large-capacitance capacitor to the strobe discharge tube so that the flash is emitted. The strobe reach distance on the side can also be increased.

  FIG. 1 is a block diagram showing a main configuration of a digital camera to which the first embodiment of the present invention is applied. The digital camera 2 is roughly divided into an imaging unit 3 and a strobe device 4. Further, a CPU 5 that controls each of the imaging unit 3 and the flash unit 4 is provided, and an operation unit 6 is connected to the CPU 5. The CPU 5 acquires a command input from the operation unit 6 according to each mode selected by the user, and controls each unit of the digital camera 2. As the operation unit 6, a release button 7, a mode selection dial 8, a strobe light emission prohibiting switch 9 and the like are provided.

  The release button 7 can be pressed into a half-pressed position where the shutter button is pressed shallowly and a fully-pressed position where the release button 7 is further pressed. By setting the release button 7 to the half-pressed position, photometry and distance measurement are performed. By setting the push position, the electronic shutter of the imaging unit 3 operates to perform imaging.

  The strobe emission prohibition switch 9 can set the presence or absence of strobe emission. When the strobe emission prohibition switch 9 is off, the strobe device 4 is driven to emit strobe light, and when the strobe emission inhibition switch 9 is turned on. The strobe device 4 does not emit strobe light.

  The imaging unit 3 includes an imaging lens 11, an aperture 12, a lens driving device 13, a solid-state imaging device 14, a timing generator 16, an amplifier 18, an A / D converter 19, an image data processing circuit 21, a frame memory 22, a display 23, and compression / decompression. The circuit 24, the media controller 26, the distance measuring sensor 27, the AF detection circuit 28, the AE detection circuit 29, and the like.

  The imaging lens 11 is moved by the lens driving device 13 and positioned at the in-focus position. A solid-state image sensor 14 is disposed behind the photographic lens 11, and the image-capturing lens 11 positioned at the in-focus position forms a subject image on the solid-state image sensor 14. The solid-state imaging device 14 is constituted by, for example, a CCD image sensor or a CMOS image sensor. The solid-state imaging device 14 is driven by a timing generator 16 controlled by the CPU 5. The subject light transmitted through the imaging lens 11 is output as R, G, and B image data by the solid-state imaging device 14. Image data output from the solid-state imaging device 14 is amplified by an amplifier 18. The A / D converter 19 converts the image data amplified by the amplifier 18 into digital image data. The image data output from the A / D converter 19 is input to the image data processing circuit 21. The image data processing circuit 21 performs image processing such as matrix calculation processing, white balance adjustment, and gamma correction on the input image data.

  The processed image data is temporarily stored in the frame memory 22. The display 23 outputs the image data stored in the frame memory 22 and displays a through image. When the release button 7 is fully pressed, the image data written in the frame memory 22 is sent to the compression / decompression circuit 24. The compression / decompression circuit 24 performs compression processing on the image data and outputs it to the media controller 26. The media controller 26 writes the compressed image file to the memory card 31. In the reproduction mode, the media controller 26 reads out the image file from the memory card 31, is decompressed by the compression / decompression circuit 24, and then is output to the display 23.

  Further, an AF detection circuit 28 and an AE detection circuit 29 are connected to the CPU 5, and the CPU 5 controls the AF detection circuit 28 to obtain distance measurement data representing the distance to the subject acquired by the distance measurement sensor 27. Based on this, the AF detection value at which the focus adjustment of the imaging lens 11 is optimal for photographing is detected, and the lens driving device 12 is controlled based on this AF detection value, and the focus lens of the imaging lens 11 is moved to the optimal position. Let Further, the CPU 40 controls the AE detection circuit 29 to detect an AE detection value at which the exposure adjustment is optimal for photographing based on the image data acquired by the solid-state imaging device 14, and based on the AE detection value, The diaphragm 12, the timing generator 16, and the like are controlled so that the exposure amount is optimized. The CPU 5 further determines the light emission amount of the strobe device 4 based on the subject distance detected by the AF detection circuit 28, the aperture value controlled by the AE detection circuit 29, and the like.

  The stroboscopic device 4 emits stroboscopic light so that an appropriate exposure amount can be obtained when the digital camera 2 is used for indoor shooting or when the subject brightness is low and auxiliary light is required. The strobe device 4 includes a strobe discharge tube 51 that emits strobe light, a light emitting capacitor 52 for storing charges applied to the strobe discharge tube 51, a charge control circuit 53 that charges the light emitting capacitor 52, and a light emitting device. A voltage detection circuit 54 that detects a charge level of the capacitor 52; a discharge voltage adjustment circuit 55 that discharges the light-emitting capacitor 52 to reduce the charge level of the light-emitting capacitor 52 when the digital camera 2 performs macro photography as described later; It comprises a trigger circuit 56 that discharges the electric charge stored in the light emitting capacitor 52 to the strobe discharge tube 51 to emit strobe light, and a power source 57.

  The charge control circuit 53 boosts the voltage supplied from the power source 57 and charges the light-emitting capacitor 52 with the boosted voltage based on the control from the CPU 51 when the strobe device 4 is in the ON state. The charge level of the light emitting capacitor 52 charged by the charge control circuit 53 is detected by the voltage detection circuit 54, and electric charges are accumulated until the charge level reaches a predetermined value. The trigger circuit 56 gives a light emission trigger to the strobe discharge tube 51 based on a light emission control signal sent from the CPU 51 to cause the strobe discharge tube 51 to emit light (discharge).

  The discharge voltage adjustment circuit 55 includes a resistor 61 as a discharge load means, a switch 62, and the like. One end of the resistor 61 is connected to the output side of the light emitting capacitor 52, and the switch 62 is controlled by a discharge control signal output from the CPU 5, and the switch 62 is turned on while the discharge control signal is being sent. When discharge from the light emitting capacitor 52 to the resistor 61 is permitted and no discharge control signal is output from the CPU 5, the switch 62 is turned off, and discharge from the light emitting capacitor 52 to the resistor 61 is prohibited. The configuration of the discharge voltage adjusting circuit 55 is not limited to this, and any configuration that can discharge the voltage of the light emitting capacitor 52 to load means other than the strobe discharge tube 51 may be used.

  The operation of the above configuration will be described with reference to the flowchart shown in FIG. When shooting with the digital camera 2, the power switch is turned on, and the mode selection dial 8 is operated to select an imaging mode from a plurality of selection modes. When the imaging mode is selected, the imaging unit 3 is turned on. At this time, if it is desired to select the flash photography, the flash emission prohibition switch 9 is operated to the off side. Then, when imaging the subject, framing is performed while viewing the display 23.

  When imaging a subject after framing, the user first pushes the release button 7 to the half-pressed position. When the release button 7 is half-pressed, the distance measuring sensor 27, the AF detection circuit 28, the AE detection circuit 29, and the lens driving device 12 are turned on to measure the subject distance and the subject brightness, and further, based on the measured values, the imaging lens 11 In-focus movement and exposure control are performed.

  After the release button 7 is half-pressed in this way, the CPU 5 determines whether the on / off of the flash photography is selected. It is determined from the detected subject distance whether or not the macro shooting is performed. That is, if the subject distance detected by the distance measuring sensor 27 is less than a predetermined value (macro area) set in advance, it is determined that the macro photography is performed. It is determined that it is a shooting.

  As described above, when the CPU 5 determines that the flash photography is on and the macro photography is selected, the CPU 5 controls the switch 62 of the discharge voltage control circuit 55 to the on side to charge the light emitting capacitor 52. The charged electric charge is discharged to the resistor 61. Then, when a predetermined time has elapsed from the start of the discharge, the voltage detection circuit 54 detects the charge level of the light emitting capacitor 52. If the voltage detection circuit 54 has dropped below the predetermined charge level, the switch 62 is turned off. When the discharge is stopped and the predetermined charge level is exceeded, the discharge is continued and the discharge is performed until it becomes less than the predetermined value.

  When the release button 7 is fully depressed, the CPU 5 controls the trigger circuit 56 to discharge the electric charge from the light emitting capacitor 52 to the strobe discharge tube 51 to perform strobe light emission, and to the solid-state image sensor 14 through the imaging lens 11. The formed subject image is recorded in the memory card 31 as image data, and one imaging is completed. At this time, when the macro shooting is determined from the subject distance, since the discharge is performed so that the charging level of the light emitting capacitor 52 is lowered, the light emission amount discharged from the strobe discharge tube 51 is adjusted to the macro shooting. It is controlled to emit a very small amount of light, and can be photographed with an appropriate exposure amount suitable for macro photography. Further, during normal photographing, the switch 62 of the discharge voltage control circuit 55 is controlled to the off side, and the discharge from the light emitting capacitor 52 to the resistor 61 is not performed and the charge level is not lowered. The discharge from the light emitting capacitor 52 to the strobe discharge tube 51 is performed with a voltage, and an image can be taken with an appropriate exposure amount. The capacity of the light-emitting capacitor 52 is large in capacity when the subject distance is on the far side in normal shooting. That is, the strobe device 4 can achieve strobe light emission with a sufficient amount of light even when the subject is at a long distance, and controls the discharge voltage to suppress the amount of light emission at macro photography. The flash can be emitted.

  In the first embodiment, the discharge voltage control means is controlled to reduce the charge level of the light emitting capacitor, thereby suppressing the strobe light emission amount and enabling macro photography with an appropriate exposure amount. However, the present invention is not limited to this. In the second embodiment of the present invention described below, when strobe light emission is performed in macro photography, the amount of strobe light emission is reduced by reducing the discharge current discharged from the light emitting capacitor to the strobe discharge tube. The same effects as those of the first embodiment can be obtained.

  FIG. 3 is a block diagram illustrating a configuration of a digital camera 70 to which the present embodiment is applied. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The digital camera 70 includes an imaging unit 3, a strobe device 71, a CPU 5, and an operation unit 6.

  The strobe device 71 includes a strobe discharge tube 51, a light emission capacitor 52, a charge control circuit 53, a voltage detection circuit 54, and the light emission capacitor 52 discharges to the strobe discharge tube 51 when the digital camera 2 performs macro photography as will be described later. It comprises a discharge current adjusting circuit 75, a trigger circuit 56, and a power source 57 for reducing the discharge current.

  The discharge current adjustment circuit 75 includes a resistor 76 as a discharge load means, a switch 77, and the like. The resistor 76 is connected between the light emitting capacitor 52 and the ground, and the switch 77 is controlled by a discharge control signal output from the CPU 5, and when the discharge control signal is sent, the switch 77 is turned on. When the electric charge is discharged from the light emitting capacitor 52 to the strobe discharge tube 51, a part of the electric charge accumulated in the light emitting capacitor 52 is discharged to the resistor 76. That is, the discharge current discharged from the light emitting capacitor 52 to the strobe discharge tube 51 is reduced, and the strobe emission amount is suppressed. When the discharge control signal is not issued, the switch 77 is turned off and the discharge from the light emitting capacitor 52 to the resistor 76 is prohibited. The configuration of the discharge current adjusting circuit is not limited to this, and any configuration that can discharge the voltage of the light emitting capacitor 52 to load means other than the strobe discharge tube 51 may be used.

  The effect | action of the said structure is demonstrated along the flowchart shown in FIG. After the framing is finished and the release button 7 is pressed halfway, when the CPU 5 determines that the flash photography is on and the macro photography is selected, the CPU 5 sends a discharge control signal to adjust the discharge current. The switch 77 of the circuit 75 is controlled to be on. When the release button 7 is fully depressed, the CPU 5 controls the trigger circuit 56 to discharge the electric charge from the light emitting capacitor 52 to the strobe discharge tube 51 to perform strobe light emission, and to the solid-state image sensor 14 through the imaging lens 11. The formed subject image is recorded in the memory card 31 as image data, and one imaging is completed. At this time, a part of the electric charge discharged from the light emitting capacitor 52 is discharged to the resistor 76, and the discharge current discharged to the strobe discharge tube 51 is reduced. Therefore, the light emission amount discharged from the strobe discharge tube 51 is The light emission is controlled to a minute amount according to the macro photography, and the photographing can be performed with an appropriate exposure amount according to the macro photography.

  In the first and second embodiments, a single light-emitting capacitor is used, and the charge stored in the light-emitting capacitor is discharged to load means other than the strobe discharge tube, so that normal shooting and macro shooting are performed. Although the strobe light emission amount is adjusted, the present invention is not limited to this. In the third embodiment of the present invention described below, two light emitting capacitors are used. When performing strobe light emission in macro photography, only one capacitor is discharged, and during normal photography, both capacitors are discharged. As a result, the strobe emission amount is adjusted, and the same effect as in the first and second embodiments is obtained.

  FIG. 5 is a block diagram showing a configuration of a digital camera 80 to which the present embodiment is applied. In FIG. 5, components using the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. The digital camera 80 includes an imaging unit 3, a strobe device 81, a CPU 5, and an operation unit 6.

  The strobe device 81 is connected to the strobe discharge tube 51, the first and second light emitting capacitors 83 and 84, the charge control circuit 53, the voltage detection circuit 54, and the macro photography and the normal photography as described later. It comprises a capacitor selection circuit 85, a trigger circuit 56, and a power source 57 for switching the number of capacitors when discharging.

  The capacitor selection circuit 85 is connected to a position between the second light emitting capacitor 84 and the ground, is controlled by a discharge control signal output from the CPU 5, and is turned on when the discharge control signal is sent. The charge accumulated in the two-light-emitting capacitor 84 is prohibited from being discharged to the strobe discharge tube 51, and is turned off when the discharge control signal is not output from the CPU 5, and the second light-emitting capacitor 84 is turned on when strobe light is emitted. The accumulated charge is allowed to be discharged to the strobe discharge tube 51. That is, when the discharge control signal is sent, only the first light emitting capacitor 83 is used for discharging to the strobe discharge tube 51 to perform strobe light emission, and when the discharge control signal is not output, the first and second light emitting capacitors are used. Both 83 and 84 are used for discharge to the strobe discharge tube 51 to emit strobe light. Note that when only one of the capacitors of the first and second light-emitting capacitors 83 and 84 is used, a very small amount of strobe light is set according to the macro shooting, and when both are used, it is adjusted to the normal shooting. The light emission amount is set.

  The effect | action of the said structure is demonstrated along the flowchart shown in FIG. After the framing is finished and the release button 7 is half-pressed, when the CPU 5 determines that the flash photography is on and the macro photography is selected, the CPU 5 transmits a discharge control signal to send a capacitor selection circuit. Turn on 85. When the release button 7 is fully pressed, the CPU 5 controls the trigger circuit 56 to discharge the electric charge from the first light emitting capacitor 83 to the strobe discharge tube 51 to perform strobe light emission. 14 is recorded in the memory card 31 as image data, and one imaging is completed. At this time, since the electric charge discharged to the strobe discharge tube 51 is discharged only from the first light emitting capacitor 83, the light emission amount discharged from the strobe discharge tube 51 is a minute amount of light emission adapted to macro photography. Therefore, it is possible to perform photographing with an appropriate exposure amount adapted to macro photography. Also, during normal shooting, the strobe selection circuit 85 is turned off, and both the first and second light-emitting capacitors 83 and 84 are discharged to the strobe discharge tube 51 to perform strobe light emission. The amount of light emission becomes so that photographing can be performed with an appropriate exposure amount.

  In the third embodiment, two light-emitting capacitors are used, and when performing strobe light emission in macro photography, only one capacitor is discharged, and in normal photography, both capacitors are discharged to perform normal photography. Although the flash emission amount is adjusted in macro photography, the present invention is not limited to this. In the fourth embodiment of the present invention described below, when using two light-emitting capacitors having different capacities to perform strobe light emission in macro photography, the capacitor is discharged from a small capacity, and during normal photography, The amount of stroboscopic light emission is adjusted by discharging from a large-capacitance capacitor, and the same effect as in the first to third embodiments is obtained.

  FIG. 7 is a block diagram showing a configuration of a digital camera 90 to which this embodiment is applied. In FIG. 7, components using the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The digital camera 90 includes an imaging unit 3, a strobe device 91, a CPU 5, and an operation unit 6.

  The strobe device 91 includes a strobe discharge tube 51, a macro light emission capacitor 93, a normal light emission capacitor 94, a charge control circuit 53, a voltage detection circuit 54, as will be described later, to the strobe discharge tube 51 in macro photography and normal photography. A capacitor switching circuit 95, a trigger circuit 56, and a power source 57 are provided for switching capacitors when discharging.

Of the capacitors 93 and 94 having different capacities, the macro light-emitting capacitor 93 is a small-capacitance capacitor, and the normal light-emitting capacitor 94 is larger in capacity than the macro light-emitting capacitor 93. As the small-capacity macro light-emitting capacitor 93, a capacitor having the minimum capacitance that can be appropriately exposed at the longest distance on the macro photographing side may be used. For example, a capacitor having a capacitance C _mn that satisfies the following expression (1): Good. In the equation, L ₁ is the maximum strobe distance, L _mn is the boundary distance between macro photography and normal photography (that is, the longest distance on the macro photography side), and C ₁ is the capacity of the normal light emitting capacitor 94.
C _mn = (L _mn / L ₁ ) ² × C ₁ (1)
In this formula, for example, when the capacitance C ₁ of the normal light emission capacitor 94 is set to 150 μF, the longest strobe distance L ₁ = 2.5 m, and the longest macro shooting side distance L _mn = 0.5 m, the macro light emission capacitor 93 is The capacitance C _mn to be secured may be as small as (0.5 / 2.5) ² × 150 = 0.04 × 150 = 6 μF.

  The capacitor switching circuit 95 is connected to a position between the normal light emitting capacitor 94 and the ground, and is controlled by a discharge control signal output from the CPU 5, and is turned on when the discharge control signal is sent, and the macro light emission. When the discharge control signal is not sent, it is turned off, and the normal light emission capacitor 94 is discharged to the strobe discharge tube 51 to cause strobe light emission. Like that.

  The operation of the above configuration will be described with reference to the flowchart shown in FIG. After the framing is finished and the release button 7 is half-pressed, when the CPU 5 determines that the flash photography is on and the macro photography is selected, the CPU 5 transmits a discharge control signal to transmit the capacitor switching circuit. Turn on 95. When the release button 7 is fully pressed, the CPU 5 controls the trigger circuit 56 to discharge the electric charge from the macro light-emitting capacitor 93 to the strobe discharge tube 51 to perform strobe light emission. The subject image formed on the image is recorded in the memory card 31 as image data, and one imaging is completed. At this time, since the electric charge discharged to the strobe discharge tube 51 is discharged only from the macro light emission capacitor 93, the light emission amount discharged from the strobe discharge tube 51 is a very small amount of light emission corresponding to macro photography. It is controlled, and it is possible to perform photographing with an appropriate exposure amount that matches macro photography. Further, in normal shooting, since the normal light emission capacitor 94 is discharged to the strobe discharge tube 51 and strobe light is emitted, the amount of light emission matches that of normal shooting, and shooting can be performed with an appropriate exposure amount. In addition, since a capacitor that matches each exposure amount is used for normal shooting and macro shooting, even when settings such as the flash range and the boundary distance between macro shooting and normal shooting are changed, This can be easily handled by simply changing the capacitor capacity. Further, since a macro light emitting capacitor having a small capacity may be used, an increase in the cost of the strobe device can be prevented.

  In the above first to fourth embodiments, examples in which the present invention is applied to a digital camera have been described.

It is a block diagram which shows the outline of a structure of the digital camera to which 1st Embodiment of this invention is applied. It is a flowchart explaining the imaging | photography process of the digital camera to which 1st Embodiment of this invention is applied. It is a block diagram which shows the outline of a structure of the digital camera to which 2nd Embodiment of this invention is applied. It is a flowchart explaining the imaging | photography process of the digital camera to which 2nd Embodiment of this invention is applied. It is a block diagram which shows the outline of a structure of the digital camera to which 3rd Embodiment of this invention is applied. It is a flowchart explaining the imaging | photography process of the digital camera to which 3rd Embodiment of this invention is applied. It is a block diagram which shows the outline of a structure of the digital camera to which 4th Embodiment of this invention is applied. It is a flowchart explaining the imaging | photography process of the digital camera to which 4th Embodiment of this invention is applied.

Explanation of symbols

2 Digital camera 4, 71, 81, 91 Strobe device 51, 71, 81, 91 Strobe discharge tube 52, 83, 84, 93, 94 Capacitor 55 Discharge voltage adjustment circuit 75 Discharge current adjustment circuit 85 Capacitor selection circuit 95 Capacitor switching circuit

Claims (8)

In the strobe light emission amount control method for controlling the light emission amount when the strobe discharge tube discharges the electric charge accumulated in the capacitor for light emission,
When a macro area is detected from a distance measuring mechanism that detects a subject distance, the light emitting capacitor is discharged to lower the charge level of the light emitting capacitor, and then discharged from the light emitting capacitor to the strobe discharge tube. A method for controlling the amount of light emitted from a strobe. In the strobe light emission amount control method for controlling the light emission amount when discharging the electric charge accumulated in the light emitting capacitor to the strobe discharge tube to emit the strobe light,
When the macro area is detected from the distance measuring mechanism that detects the object distance, the light emitting capacitor is discharged to reduce the discharge current discharged to the strobe discharge tube, and from the light emitting capacitor to the strobe discharge tube. A method for controlling the amount of stroboscopic light emission, characterized in that the stroboscopic light is emitted by discharging to a stroboscopic light. In the strobe light emission amount control method for controlling the light emission amount when discharging the electric charge accumulated in the light emitting capacitor to the strobe discharge tube to emit the strobe light,
When the macro area is detected from a distance measuring mechanism that detects the subject distance, the light emitting capacitor is composed of two capacitors, and discharges from only one of the capacitors to the strobe discharge tube. A strobe emission amount control method, wherein two strobes are discharged to the strobe discharge tube to emit strobe light. In the strobe light emission amount control method for controlling the light emission amount when discharging the electric charge accumulated in the light emitting capacitor to the strobe discharge tube to emit the strobe light,
The light emitting capacitor is composed of two capacitors having large and small capacities, and when the macro area is detected from the distance measuring mechanism that detects the subject distance, the small capacity capacitor is discharged to the strobe discharge tube, And a strobe emission control method, characterized in that a strobe light is emitted by discharging from a large-capacitance capacitor to the strobe discharge tube. Built in a camera equipped with a distance measuring mechanism for measuring a subject distance, a light emitting capacitor, a charging circuit for charging the light emitting capacitor, a strobe discharge tube, and a charge accumulated in the light emitting capacitor are supplied to the strobe discharge tube. In a strobe device consisting of a light emitting circuit that discharges and strobes,
A discharge voltage adjusting circuit for reducing the charge level of the light emitting capacitor by discharging the electric charge accumulated in the light emitting capacitor to a load means other than the strobe discharge tube, and the subject measured by the distance measuring mechanism When a macro region is detected from a distance, the discharge voltage adjusting circuit is controlled to lower a charge level of the light emitting capacitor, and then the light emitting capacitor is discharged to a strobe discharge tube to emit strobe light. Strobe device. Built in a camera equipped with a distance measuring mechanism for measuring a subject distance, a light emitting capacitor, a charging circuit for charging the light emitting capacitor, a strobe discharge tube, and a charge accumulated in the light emitting capacitor are supplied to the strobe discharge tube. In a strobe device consisting of a light emitting circuit that discharges and strobes,
A discharge current adjusting circuit for reducing the discharge current discharged to the strobe discharge tube by discharging the charge accumulated in the light emitting capacitor to a load means other than the strobe discharge tube; When the macro area is detected from the measured subject distance, the discharge current adjusting circuit is controlled to reduce the discharge current discharged to the strobe discharge tube, and then the discharge capacitor is discharged from the light emitting capacitor to the strobe discharge tube. A strobe device that emits strobe light. Built in a camera equipped with a distance measuring mechanism for measuring a subject distance, a light emitting capacitor, a charging circuit for charging the light emitting capacitor, a strobe discharge tube, and a charge accumulated in the light emitting capacitor are supplied to the strobe discharge tube. In a strobe device consisting of a light emitting circuit that discharges and strobes,
The light emitting capacitor is composed of two capacitors. When a macro area is detected from the subject distance measured by the distance measuring mechanism, only one of the capacitors is discharged to the strobe discharge tube, and the macro A strobe device comprising capacitor selecting means for discharging the two capacitors from the two capacitors to the strobe discharge tube and emitting strobe light when the area is not in the area. Built in a camera equipped with a distance measuring mechanism for measuring a subject distance, a light emitting capacitor, a charging circuit for charging the light emitting capacitor, a strobe discharge tube, and a charge accumulated in the light emitting capacitor are supplied to the strobe discharge tube. In a strobe device consisting of a light emitting circuit that discharges and strobes,
The light emitting capacitor includes a normal light emitting capacitor and a macro light emitting capacitor having a smaller capacity than the normal light emitting capacitor. When the macro area is detected from the subject distance measured by the distance measuring mechanism, the macro light emitting A strobe device comprising capacitor switching means for discharging the strobe discharge tube only from the capacitor for use in the strobe discharge tube and discharging the strobe discharge tube from the normal light emission capacitor to the strobe discharge tube outside the macro region.

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