JP2005115060A - External flash device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an external flash device for displaying an accurate modulated light distance range even in a camera performed in automation by changing the margin of a margin regulation circuit by sensitivity setting of an imaging device. <P>SOLUTION: The minimum sensitivity information and the maximum sensitivity information capable of automatic regulation and diaphragm value information of the camera are communicated with the external flash device 11 from the camera having an automatically regulating function, by changing the margin of the margin regulation circuit concerning the sensitivity of an imaging device 4 during photographing. CPU 12 of the external flash device 11 calculates a distance range of capable modulated light by the external flash device on the basis of the communicated information to display the calculated result on an LCD panel 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an external flash device that is detachable from a camera.

  Various proposals have been made in the field of flash devices that emit light toward a subject. For example, Patent Document 1 proposes a technique for widening a distance range that can be dimmed by a flash device. That is, the technique proposed in Patent Document 1 sets the gain value of the image signal acquired by the image sensor based on the calculated subject distance, and sets the dimming value in the strobe dimming unit to perform flash photography. Is to do.

で示す式が用いられる。ここで、Ｇ＿ｎｏはフラッシュ装置のＩＳＯ１００相当のガイドナンバーである。また、設定ＩＳＯは自動設定若しくは手動設定された感度値（ＩＳＯ感度値）であり、Ｆ値は絞り値である。
特開２０００−１３４５３３号公報 A range of distance that can be dimmed by the flash device (hereinafter referred to as a dimming interlocking distance range) can also be calculated from a value such as an aperture value. In such distance calculation,

Is used. Here, G_no is a guide number equivalent to ISO 100 of the flash device. The set ISO is an automatically set or manually set sensitivity value (ISO sensitivity value), and the F value is an aperture value.
JP 2000-134533 A

  Here, many digital cameras are configured so that the sensitivity of the image sensor at the time of shooting can be automatically adjusted by changing the gain (gain) of a gain adjustment circuit, for example, an AGC amplifier. In such a case, as can be seen from the above formula, the dimming interlocking distance range changes depending on the sensitivity range that can be automatically adjusted. Further, such a sensitivity range that can be automatically adjusted varies depending on the type of camera. Therefore, when the dimming interlocking distance range is displayed on an external flash device that is detachable from the camera, the accurate dimming interlocking distance range cannot be displayed. This is because the external flash device is not designed for each individual camera, and there is no accurate sensitivity range information on the external flash side.

  The present invention has been made in view of the above circumstances, and an accurate dimming interlocking distance range can be displayed even in a camera in which sensitivity setting of an image sensor is automatically performed by changing the gain of a gain adjustment circuit. An object of the present invention is to provide an external flash device that can be used.

  In order to achieve the above object, the external flash device according to the first aspect of the present invention is detachably attachable to a camera having a function of automatically adjusting the sensitivity of the image sensor at the time of shooting by changing the gain of the gain adjusting circuit. An external flash device that receives at least the minimum sensitivity information and the maximum sensitivity information within a range in which the sensitivity of the light emitting means and the image sensor can be automatically adjusted, and the aperture value information of the camera from the camera. Communication means, calculation means for calculating a distance range dimmable by the light emitting means based on information communicated through the communication means, and display means for displaying the distance range calculated by the calculation means It comprises.

  According to the first aspect, by communicating information necessary for calculation of the dimming interlocking distance range from the camera to the external flash device, an accurate dimming interlocking distance range can be calculated and displayed.

  According to the present invention, it is possible to provide an external flash device capable of displaying an accurate dimming interlocking distance range even in a camera in which sensitivity setting of an image sensor is automatically performed by changing the gain of a gain adjustment circuit. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a camera system including a camera 1 and an external flash device 11 according to an embodiment of the present invention configured to be detachable from the camera 1. In other words, the external flash device 11 is detachable via the hot shoe 7 provided in the camera 1. When the external flash device 11 is thus attached to the camera 1, bidirectional communication between the CPU 6 inside the camera 1 and the CPU 12 inside the external flash device 11 becomes possible. Here, FIG. 1 shows a communication line for communicating data between the camera 1 side and the external flash device 11 side, and X for instructing flash emission from the camera 1 side to the external flash device 11 side. A communication line for communication of a switch (SW) signal is illustrated.

  First, the camera 1 will be described. Here, the camera 1 in FIG. 1 is assumed to be a digital camera. Further, as the internal configuration of the camera 1, a conventionally well-known configuration may be used, and hence the detailed description of the camera 1 is omitted hereinafter.

  The photographing optical system 2 is composed of a plurality of lenses, and forms an image on the image sensor 4 with a light beam from a subject (not shown). Here, the photographing optical system 2 is configured to be driven in the optical axis direction by a lens driving unit (not shown) configured by a step motor or the like.

  The diaphragm 3 is an opening for adjusting the amount of incident light flux that has entered through the photographing optical system 2. Here, the size of the aperture of the diaphragm 3 is configured to be adjustable by a diaphragm driving unit (not shown).

  In other words, a light beam from a subject (not shown) that has entered through the photographing optical system 2 forms an image on the image sensor 4 via a diaphragm 3 or a shutter (not shown). The image sensor 4 converts this light beam into an electrical signal and outputs it to the AGC amplifier 5. The AGC amplifier 5 amplifies the electrical signal output from the image sensor 4 with a predetermined gain value. This amplification is performed according to the sensitivity value set by the user, the sensitivity automatically adjusted by the CPU 6, or the like. That is, the sensitivity of the image sensor 4 can be adjusted in a pseudo manner by adjusting the gain value of the AGC amplifier.

  Thereafter, the CPU 6 digitizes and reads the signal amplified by the AGC amplifier 5. Thereafter, the CPU 6 performs predetermined image processing or the like on the read signal to generate image data, and records this image data on a recording medium (not shown). The CPU 6 also controls the entire camera such as the control of the photographing optical system 2, the control of the diaphragm 3, and the control of the AGC amplifier 5.

  Here, the CPU 6 communicates the lens position information of the photographing optical system 2 and the aperture value information (F value) of the aperture 3 to the external flash unit 11. The ISO sensitivity information set by the camera 1 is also communicated to the external flash device 11. In particular, in the present embodiment, in a mode in which the optimum ISO sensitivity at the time of shooting is automatically adjusted by the CPU 6 (hereinafter, this mode is referred to as “auto ISO mode”), the CPU 6 automatically uses the camera 1. Data of the maximum adjustable ISO sensitivity (hereinafter referred to as MAX_ISO) and the minimum ISO sensitivity (hereinafter referred to as MIN_ISO) are communicated to the external flash device 11.

Next, the external flash device 11 according to the present embodiment will be described.
The CPU 12 is a control circuit that controls the entire external flash device 11. That is, when various commands and various data are received from the CPU 6, various controls of the external flash device are executed via the control IC 16. In addition, an operation switch (SW) 13 is connected to the CPU 12, and the CPU 12 determines an operation state of the operation SW 13 and executes various controls according to the determination result.

  The EEPROM 14 is a memory in which various control programs executed by the CPU 12 and various setting values such as a charging voltage are stored. Furthermore, the power supply 15 is a power supply for the external flash device 11 that operates under the control of the CPU 12. That is, the power supply 15 supplies power to each part inside the external flash device 11. The power supply 15 also guarantees the power supply operation of the control system during the charging operation of the external flash device 11.

  The charging unit 17 performs charging control during flash emission according to an instruction from the CPU 12. Here, the charging voltage in the charging unit 17 is monitored by monitoring the voltage of a charging capacitor (not shown) of the charging unit 17 in the CPU 12 via the control IC 16. When the CPU 12 receives the XSW signal from the camera 1 side, the CPU 12 sends a light emission start signal to the charging unit 17 via the control IC 16.

  The light emitting unit 18 receives the light emission start signal from the CPU 12 and causes the xenon (Xe) tube 20 to discharge light. The emitted light is reflected by the reflector 19 and then irradiated to a subject (not shown) via the light emitting panel 21.

  The optical sensor 22 and the optical sensor 23 are sensors for detecting the light emission amount at the time of flash emission. Here, the optical sensor 22 is a sensor that is disposed in the vicinity of the Xe tube 20 and directly receives the light emitted from the Xe tube 20. The control IC 16 controls the light emission amount according to the light reception result of the optical sensor 22. On the other hand, the optical sensor 23 is a sensor that monitors the amount of reflected light from a subject (not shown). The control IC 16 stops the light emitting operation of the light emitting unit 18 when the voltage obtained by integrating the reflected light received by the optical sensor 23 reaches a predetermined voltage.

  The external flash device 11 can be zoomed. That is, the external flash unit 11 can change the irradiation angle at the time of flash emission by zooming the light emitter, here the Xe tube 20. The zoom control unit 24 performs such zoom drive control. For example, if the zoom position is set to the wide-angle side, the irradiation angle becomes wide, and if the zoom position is set to the telephoto side, light can be emitted far away.

  The LCD panel 25 is a monitor on which various setting information of the external flash device 11 is displayed. Here, in the present embodiment, the dimmable distance range of the external flash device is displayed on the LCD panel 25 as the dimming interlocking distance range. Such calculation of the dimming interlocking distance range is performed by the CPU 12. The dimming interlocking distance range calculation and display control will be described with reference to the flowchart of FIG.

  That is, the CPU 12 receives the focal length information of the photographing optical system 2 from the camera 1 side (step S1). The CPU 12 calculates the zoom position of the external flash device based on the received focal length information (step S2).

  Next, the CPU 12 receives MIN_ISO information from the camera 1 side (step S3) and also receives MAX_ISO information (step S4). Further, the CPU 12 receives F value information from the camera 1 side (step S5).

  Thereafter, the CPU 12 calculates the minimum guide number (hereinafter referred to as MIN_Gno) and the maximum guide number (hereinafter referred to as MAX_Gno) at ISO 100 from the zoom position information of the external flash device (step S6). Here, as a method of calculating these guide numbers, for example, MIN_Gno and MAX_Gno table data corresponding to the zoom position of the external flash device may be stored in the EEPROM 14. That is, the CPU 12 calculates MIN_Gno and MAX_Gno with reference to this table data.

によって算出できる。即ち、調光連動距離範囲の演算においては、近距離側の調光可能な距離と遠距離側の調光可能な距離とを演算する。 Next, the CPU 12 calculates the dimming interlocking distance range (step S7). Here, the dimming interlocking distance range is

Can be calculated. That is, in the calculation of the dimming interlocking distance range, the dimmable distance on the short distance side and the dimmable distance on the long distance side are calculated.

  Thereafter, the CPU 12 displays the distance on the short distance side and the distance on the long distance side calculated in step S7 on the LCD panel 25 as indicated by reference numeral 26 in FIG. 3 (step S8).

  That is, in the present embodiment, even if the sensitivity of the camera is automatically adjustable, the minimum sensitivity value and the maximum sensitivity value that can be adjusted by the camera are communicated to the external flash device, so that an accurate interlocking distance can be obtained. Range calculation can be performed.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention. For example, in each of the above formulas, the ISO sensitivity standard is ISO 100, but it goes without saying that the present invention is not limited to this. Further, the sensitivity information for communication is not limited to ISO sensitivity. Further, the display of the distance range is not limited to the metric system.

  Further, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

1 is a configuration diagram of a camera system including a camera and an external flash device according to an embodiment of the present invention configured to be detachable from the camera. It is a flowchart which shows the control procedure of the light control interlocking distance range display in the external flash device which concerns on one Embodiment of this invention. It is a display example of a dimming interlocking distance range display.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Camera, 2 ... Shooting optical system, 3 ... Aperture, 4 ... Image sensor, 5 ... AGC amplifier, 6, 12 ... CPU, 7 ... Hot shoe, 11 ... External flash device, 13 ... Operation switch (SW), 14 ... Program memory (EEPROM), 15 ... Power supply, 16 ... Control IC, 17 ... Charging part, 18 ... Light emitting part, 19 ... Reflective umbrella, 20 ... Xenon (Xe) tube, 21 ... Light emitting panel, 22, 23 ... Light sensor 24 ... zoom control unit, 25 ... LCD panel

Claims (2)

An external flash device that can be attached to and detached from a camera having a function of automatically adjusting the sensitivity of an image sensor at the time of shooting by changing the gain of a gain adjustment circuit,
Light emitting means;
Communication means for receiving at least the minimum sensitivity information and the maximum sensitivity information in a range in which the sensitivity of the image sensor can be automatically adjusted, and the aperture value information of the camera, from the camera;
Based on the information communicated through the communication means, computing means for computing a distance range that can be dimmed by the light emitting means,
Display means for displaying the distance range calculated by the calculating means;
An external flash device comprising: The calculation of the distance range by the calculating means calculates the distance on the short distance side that can be dimmed by the light emitting means based on at least the minimum sensitivity information and the aperture value information, and at least the maximum sensitivity information and Based on the aperture value information, by calculating the distance on the far side that can be dimmed by the light emitting means,
2. The external flash device according to claim 1, wherein the display of the distance range by the display means is performed by displaying the distance on the near side and the distance on the far side.

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