JP2005148227A - Camera system and flashing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera system with which a light control feasible distance at which an object is photographed with proper exposure is easily grasped and to provide a flashing device. <P>SOLUTION: The camera system is equipped with a photographing mechanism having an imaging lens, a diaphragm, a shutter means and an imaging part; a camera control part controlling the respective parts of the photographing mechanism and acquiring necessary emitted light quantity, the diaphragm value of the diaphragm, the shutter fully open time of the shutter means and the sensitivity information of the imaging part; a flash light emitting part emitting flash light in photographing by the photographing mechanism; a light emission control part stopping the light emission of the flash light emitting part either at light emission allowable time corresponding to the necessary emitted light quantity reaching time or at light emission allowable time corresponding to the shutter fully open time; an effective emitted light quantity arithmetic means arithmetically calculating the upper limit value of effective emitted light quantity by the stop of the light emission at the light emission allowable time; a light control feasible distance arithmetic means arithmetically calculating the light control feasible distance at which the exposure by the flash light emitting part is properly performed based on the upper limit value of the effective emitted light quantity changed according to the shutter fully open state, the diaphragm value and the sensitivity information of the imaging part; and a display part displaying the light control feasible distance. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a camera system and a flash device capable of grasping in advance a light controllable distance at which exposure in a flash light emitting unit is appropriately executed.

  2. Description of the Related Art Conventionally, a flash device that emits light from a xenon arc tube using electric charges accumulated in a capacitor has been used as a flash device such as a camera for photographing. When flash photography is performed with a camera, reflected light from the subject illuminated by the flash device is received by the light metering light metering element, and the time integration amount of the photometric value reaches a preset light emission level. Control for stopping the light emission of the flash device is performed.

  In particular, in a silver halide camera equipped with a focal plane shutter, when the trailing curtain starts running while the flash device is emitting light, a difference in exposure amount occurs for each location in the exposure area, resulting in unevenness in the subject image. . Therefore, in order to complete the light emission of the flash device within the shutter fully open time (the time from the completion of the first curtain run to the start of the second curtain run) and shorten the synchro-sync time, the above-described light emission control is performed. Indispensable.

On the other hand, in an electronic camera equipped with an electronic shutter, even if the flash device continues to emit light after the electronic shutter is closed, the subject image is not uneven, but there is a risk of image deterioration due to blooming or smearing. Therefore, in the electronic camera, it is desirable to complete the light emission of the flash device before the electronic shutter is closed. For example, Patent Document 1 discloses an electronic camera that performs charge transfer of a CCD after a predetermined time delay after the flash emission is stopped.
JP-A-10-243299

  Here, when the flash device stops emitting light during flash photography of the camera, the amount of light emission is smaller than when the flash device is fully lit. Therefore, the light controllable distance at which the subject can be photographed with appropriate exposure when the light emission is stopped varies greatly. However, it is very difficult to accurately grasp the range of the dimmable distance that varies depending on the photographing conditions such as the shutter speed and the aperture value.

  The present invention has been made to solve the above-described problems of the prior art, and its purpose is to easily provide a dimmable distance at which a subject can be photographed with an appropriate exposure when the flash device of the camera is stopped. It is to provide a camera system and a flash device that can be grasped.

  The invention of claim 1 includes an imaging mechanism, a camera control unit, a flash light emission unit, a light emission control unit, an effective light emission amount calculation unit, a dimmable distance calculation unit, and a display unit. It is a camera system. The photographing mechanism includes an imaging lens, a diaphragm, shutter means, and an imaging unit. The camera control unit controls each unit of the photographing mechanism, and acquires a necessary light emission amount, an aperture value of the diaphragm, a shutter fully open time of the shutter unit, and imaging unit sensitivity information. The flash light emitting unit emits flash light during photographing by the photographing mechanism. The light emission control unit stops the light emission of the flash light emitting unit either at the time when the necessary light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time. The effective light emission amount calculating means calculates an upper limit value of the effective light emission amount by stopping the light emission in the light emission allowable time. The light controllable distance calculation means is a control for appropriately performing exposure in the flash light emitting unit based on the upper limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information that change according to the shutter fully open time. Calculate the possible light distance. The display unit displays the dimmable distance.

According to a second aspect of the present invention, in the first aspect of the present invention, the image pickup unit is an image pickup device that photoelectrically converts a subject image, and the shutter unit is an electronic shutter.
According to a third aspect of the present invention, in the first aspect of the invention, the shutter unit is a focal plane shutter, and the camera control unit further acquires shutter second time information and shutter curtain travel time information of the shutter unit. Features.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the camera system includes a camera and a flash device that can be attached to the camera. The camera includes the photographing mechanism, the camera control unit, and a communication unit that transfers the necessary light emission amount, the aperture value, the shutter full open time, and the imaging unit sensitivity information to the flash device. The flash device includes a receiving unit that receives the aperture value, the shutter full open time, and the imaging unit sensitivity information transmitted from the communication unit, the flash light emitting unit, the light emission control unit, and the effective light emission amount calculation. Means, the dimmable distance calculating means, and the display unit.

  According to a fifth aspect of the present invention, in the third aspect of the invention, the camera system includes a camera and a flash device attachable to the camera. The camera is configured to communicate the imaging mechanism, the camera control unit, the required light emission amount, the aperture value, the shutter time information, the shutter curtain travel time information, and the imaging unit sensitivity information to the flash device. A part. The flash device includes a receiving unit that receives the shutter time information, the shutter curtain travel time information, and the imaging unit sensitivity information transmitted from the communication unit, and the shutter second time information and the shutter curtain travel time information. A shutter full open time calculating means for calculating the shutter full open time; the flash light emitting section; the light emission control section; the effective light emission amount calculating means; the dimmable distance calculating means; and the display section. .

  According to a sixth aspect of the present invention, there is provided a flash device that is attached to a camera having a communication unit that transfers necessary light emission amount, aperture value, shutter full open time, and imaging unit sensitivity information, and constitutes a camera system together with the camera. The apparatus includes a receiving unit, a flash light emitting unit that performs flash light emission, a light emission control unit, an effective light emission amount calculating unit, a dimmable distance calculating unit, and a display unit. The receiving unit receives the necessary light emission amount, the aperture value, the shutter fully open time, and the imaging unit sensitivity information from the communication unit. The light emission control unit stops the light emission of the flash light emitting unit either at the time when the necessary light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time. The effective light emission amount calculating means calculates an upper limit value of the effective light emission amount by stopping the light emission in the light emission allowable time. The light controllable distance calculation means is a control for appropriately performing exposure in the flash light emitting unit based on the upper limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information that change according to the shutter fully open time. Calculate the possible light distance. The display unit displays the dimmable distance.

  The invention according to claim 7 is attached to a camera having a communication unit for transferring the required light emission amount, aperture value, shutter second time information, shutter curtain travel time information, and image pickup unit sensitivity information, and the flash that constitutes the camera system together with the camera. The flash device includes a receiving unit, a shutter full open time calculating unit, a flash emitting unit that performs flash emission, a light emission control unit, an effective light emission amount calculating unit, a dimmable distance calculating unit, And a display unit. The receiving unit receives the required light emission amount, the aperture value, shutter time information, shutter curtain travel time information, and the imaging unit sensitivity information from the communication unit. The shutter full open time calculating means calculates the shutter full open time from the shutter second time information and the shutter curtain travel time information. The light emission control unit stops the light emission of the flash light emitting unit either at the time when the necessary light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time. The effective light emission amount calculating means calculates an upper limit value of the effective light emission amount by stopping the light emission in the light emission allowable time. The upper limit value of the effective light emission amount that changes depending on the shutter full open time, the aperture value, and the imaging unit sensitivity information. Based on this, the light controllable distance at which the exposure by the flash light emitting unit is appropriately executed is calculated. The display unit displays the dimmable distance.

  According to the present invention, in a camera system equipped with a flash device capable of controlling light emission stop, the dimmable distance that is changed according to the shutter speed is displayed on the display unit, so that an appropriate exposure can be obtained. The distance that can be adjusted is easily grasped.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Configuration of the first embodiment)
FIG. 1 is a schematic diagram of a camera system according to a first embodiment of the present invention (corresponding to the camera system of claims 1, 3, 4 and the flash device of claim 6). The camera system 1 according to the first embodiment includes a camera body 2 that is a single-lens reflex type silver salt camera and a flash device 3 attached to the camera body 2.

The camera body 2 includes a photographing mechanism, a split photometry unit 4, a light control photometry unit 5, a body microcomputer 6 that controls and controls each unit of the camera body 2, and a communication unit 7 that is connected to the flash device 3 in signal connection. Have.
The photographing mechanism of the camera body 2 includes a photographing lens system 8, an aperture mechanism 9, a focal plane shutter 10, a film 11, a quick return mirror 12, a diffusion screen 13, a condenser lens 14, a pentaprism 15, The eyepiece 16 is composed of a photometric prism 17 and a photometric lens 18.

The taking lens system 8 is configured by combining a plurality of lenses, and adjusts the relative distance between the lenses by a driving mechanism (not shown). The diaphragm mechanism 9 varies the diaphragm diameter by changing the positions of the plurality of diaphragm blades by rotating the cam.
The quick return mirror 12 is inclined in front of the focal plane shutter 10 and the film 11, and is flipped up at the time of release so as to be retracted from the photographing optical path. Normally, the light beam that has passed through the photographic lens system 8 is reflected upward by the quick return mirror 12 and forms an image once on the diffusion screen 13. Thereafter, the light passes through the condenser lens 14, the pentaprism 15, and the eyepiece lens 16 and reaches the photographer's eyes. Further, part of the light beam diffused by the diffusion screen 13 passes through the condenser lens 14, the pentaprism 15, the photometric prism 17, and the photometric lens 18, and is re-imaged by the divided photometric unit 4.

  The divided photometry unit 4 is configured by arranging a light receiving element such as a CCD, and measures a luminance value of a subject by dividing a photographed image into a plurality of regions. The output of the split photometry unit 4 is connected to the body microcomputer 6, and the photometric value of the split photometry unit 4 is output to the body microcomputer 6. Further, the light metering unit 5 for light control photoelectrically converts subject light incident from the photographing lens system 8 and reflected on the film surface at the time of release, and accumulates photocurrent in a capacitor to monitor the exposure state of the film 11. The output of the light metering unit 5 for light control is connected to the body microcomputer 6.

The body microcomputer 6 controls a series of operations of the camera body 2 according to a sequence program stored in a ROM (not shown). The body microcomputer 6 executes a known exposure calculation from the brightness value acquired by the divided photometry unit 4, and calculates the shutter time, the shutter fully open time and the aperture value, and the necessary light emission amount for the main light emission.
Further, the body microcomputer 6 exchanges information necessary for photographing with the flash device 3 via the communication unit 7. Here, information exchanged between the camera body 2 and the flash device 3 is as follows. For example, from the camera body 2 side, the shutter fully open time, the aperture value, the ISO sensitivity of the film 11 (imaging unit sensitivity information), the shooting distance, the exposure mode, the focal length of the lens, the notification signal when the required light emission amount is reached, etc. From the flash device 3 side, it is a dimming mode.

On the other hand, the flash device 3 includes a power supply 19 for supplying voltage to each circuit, a power switch 20, a capacitor 21, a booster circuit 22, a xenon arc tube 23, a light emission control circuit 24, an arithmetic control circuit 25, a photometry circuit 26, and a receiver 27. The storage unit 28 and the display unit 29 are provided.
The capacitor 21 of the flash device 3 is a main capacitor that stores light emission energy. The booster circuit 22 boosts the voltage supplied by the instruction of the arithmetic control circuit 25 and charges the capacitor 21. The light emission control circuit 24 includes a switching element such as an IGBT, and supplies or stops the charge stored in the capacitor 21 to the xenon arc tube 23 to control light emission of the xenon arc tube 23.

The arithmetic control circuit 25 includes a microprocessor and the like, and includes a photometric circuit 26 that measures the light emission amount of the xenon arc tube 23, a receiver 27 that is signal-connected to the communication unit 7 of the camera body 2, a storage unit 28, a display The unit 29 is connected.
In addition, one end of signal lines BLK, TG, and STP is connected to the arithmetic control circuit 25. The other end of the signal line BLK is connected to the booster circuit 22. On the signal line BLK, a signal indicating the start of the boost operation (for example, high level “H”) and a signal indicating the stop (for example, low level “L”) are output from the arithmetic control circuit 25 to the boost circuit 22. The other ends of the signal lines TG and STG are connected to the light emission control circuit 24. A signal indicating the light emission start of the xenon arc tube 23 is output from the arithmetic control circuit 25 to the light emission control circuit 24 on the signal line TG, and a signal indicating the light emission stop of the xenon arc tube 23 is output on the signal line STP.

Furthermore, the calculation control circuit 25 functions as an effective light emission amount calculation unit and a dimmable distance calculation unit, and executes the following calculation and control.
First, the arithmetic control circuit 25 stops the light emission of the xenon arc tube 23 in the following two cases. Specifically, either (1) when the light emission amount of the flash device 3 reaches the required light emission amount transmitted from the camera body 2, or (2) when the light emission allowable time corresponding to the shutter fully open time has elapsed. The emission of the xenon arc tube 23 is stopped. This is because, in the case of (1), if the flash device 3 continues to emit light after reaching the required light emission amount, it is overexposed. On the other hand, in the case of (2), since the trailing curtain starts running while the flash device 3 is emitting light, a difference in exposure amount occurs for each position of the exposure region, and the subject image becomes uneven. is there.

  Here, in the first embodiment, the “light emission allowable time” means the shutter full open time or the total time of the shutter full open time and a slight delay time. That is, in the present invention, not only when the light emission of the flash device 3 is stopped in the shutter full open time, but also in order to bring the effective light emission amount close to the necessary light emission amount when the light amount is insufficient, a slight delay time after the shutter full open time elapses. This is intended to include the case where the flash device 3 is stopped from emitting light after opening (see FIG. 2). In the latter case, since the flash device 3 continues to emit light after the shutter 10 starts to run on the rear curtain, strictly, slight exposure unevenness occurs. However, in the present invention, the exposure amount is allowed by allowing minute exposure unevenness. To get a better picture.

  Second, the arithmetic control circuit 3 obtains an upper limit value of the effective light emission amount when the light emission is stopped within the light emission allowable time. Here, the upper limit value of the effective light emission amount is a value of the light emission amount when the light emission is stopped when the light emission allowable time has elapsed, and varies depending on the shutter full open time. In the first embodiment, the arithmetic control circuit 25 acquires the upper limit value of the effective light emission amount corresponding to the shutter fully open time from the storage unit 28. Further, the lower limit value of the effective light emission amount is a value of the light emission amount when the light emission is stopped immediately after the light emission is started. This lower limit value is an eigenvalue determined from the performance of the flash device 3, and is not affected by the shutter fully open time. The lower limit value of the effective light emission amount is recorded in the arithmetic control circuit 25.

  Third, the arithmetic control circuit 25 is an upper limit value of the effective light emission guide number that represents the aperture value obtained from the camera body 2 and the ISO sensitivity (imaging unit sensitivity information) of the film 11 and the above-mentioned effective light emission amount as a guide number. Then, from the lower limit value, the upper limit value and lower limit value of the dimmable distance are calculated by the following equation (1). The upper and lower limits of the dimmable distance are output to the display unit.

記憶部２８はデータ格納部とデータ読み出し部とから構成されている。記憶部２８のデータ格納部には、シャッタ全開時間と、シャッタ全開時間に対応する発光許容時間での有効発光量（有効発光量の上限値）との対応関係が格納されている。一方、記憶部２８のデータ読み出し部は、入力されたシャッタ全開時間に対応する有効発光量の上限値のデータをデータ格納部から読み出して、演算制御回路２５に出力する。

The storage unit 28 includes a data storage unit and a data reading unit. The data storage unit of the storage unit 28 stores a correspondence relationship between the shutter full open time and the effective light emission amount (the upper limit value of the effective light emission amount) in the light emission allowable time corresponding to the shutter full open time. On the other hand, the data reading unit of the storage unit 28 reads the data of the upper limit value of the effective light emission amount corresponding to the input shutter full open time from the data storage unit, and outputs it to the arithmetic control circuit 25.

As shown in FIG. 3, the display unit 29 displays information such as the upper and lower limits of the dimmable distance output from the arithmetic control circuit 25, imaging unit sensitivity information, and aperture value.
(Operation of the first embodiment)
The camera system 1 of 1st Embodiment is comprised as mentioned above, and demonstrates the operation | movement below, referring the flowchart of FIG.

Step S1: First, the user attaches the flash device 3 to the camera body 2, and then turns on the power switch 21 of the flash device 3 so that the flash device 3 can be used.
Step S2: The user makes a predetermined input such as half-pressing the release button to the camera body 2. Then, the body microcomputer 6 of the camera body 2 takes in the luminance information of the subject from the divided photometry unit 4. Then, the body microcomputer 6 performs an exposure calculation based on the luminance information, and determines an exposure condition (aperture value, shutter time, and shutter full open time) at the time of shooting.

Step S3: The body microcomputer 6 transmits the aperture value, the shutter full open time, and the imaging unit sensitivity information to the arithmetic control circuit 25 of the flash device 3.
Step S4: The arithmetic control circuit 25 outputs the acquired shutter full open time to the storage unit 28. The storage unit 28 reads the data of the upper limit value of the effective light emission amount corresponding to the input shutter full open time, and outputs it to the arithmetic control circuit 25.

Step S5: The calculation control circuit 25 calculates the upper limit value of the dimmable distance from the acquired upper limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information. At the same time, the arithmetic control circuit 25 reads the lower limit value of the effective light emission amount, and calculates the lower limit value of the dimmable distance from the lower limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information.
Step S6: The arithmetic control circuit 25 outputs the upper limit value and lower limit value of the dimmable distance, the imaging unit sensitivity information, and the aperture value to the display unit 29 and displays them on the display unit 29.

Step S7: The user confirms the display of the upper limit value and the lower limit value of the dimmable distance on the display unit 29, and determines whether to start photographing. When shooting is started (YES side), the process proceeds to the shooting operation in step S8. If shooting is not started (NO side), the process returns to step S2 to reset the shutter speed and aperture value.
Step S8: The user presses the release button to start shooting. The body microcomputer 6 of the camera body 2 jumps up the quick return mirror 12 and retracts from the photographing optical path. Then, the front curtain of the focal plane shutter 10 is caused to travel, and exposure of the subject image on the film 11 is started. On the other hand, the flash device 3 sets the signal line TG to “H” in synchronization with the shutter fully opened, and starts the light emission of the xenon arc tube 23. Further, the arithmetic control circuit 25 starts counting the allowable emission time from the start of light emission of the xenon arc tube 23. Note that the light emitted from the flash device 3 is monitored by the light metering metering unit 5 of the camera body 2, and when the necessary light emission amount is reached, a notification signal when the necessary light emission amount is reached is sent from the body microcomputer 6 to the arithmetic control circuit 25. Is output.

Step S9: The arithmetic control circuit 25 determines whether or not a notification signal when the necessary light emission amount is reached is input from the body microcomputer 6. When the notification signal is input (YES side), the process proceeds to step S10. When no notification signal is input (NO side), the process proceeds to step S11.
Step S10: The arithmetic control circuit 25 sets the signal line STP to “H” in response to the input of the notification signal when the required light emission amount is reached, and stops the light emission of the xenon arc tube 23 within the light emission allowable time. In this case, the light emitted from the xenon arc tube 23 is emitted with a necessary light amount capable of realizing proper exposure. Thereafter, the body microcomputer 6 of the camera body 2 runs the shutter rear curtain at a predetermined timing, and the exposure of the film 11 is completed.

Step S11: The arithmetic control circuit 25 determines whether or not the allowable light emission time has elapsed. When the allowable light emission time has elapsed (YES side), the process proceeds to step S12. If the allowable light emission time has not elapsed, the process returns to step S9.
Step S12: The arithmetic control circuit 25 sets the signal line STP to “H” when the allowable light emission time elapses, and stops the light emission of the xenon arc tube 23 when the allowable light emission time elapses. In this case, the xenon arc tube 23 emits light at the upper limit of the effective light emission amount (see FIG. 2). Then, before and after the emission of the xenon arc tube 23 is stopped, the body microcomputer 6 of the camera body 2 runs the shutter rear curtain at a predetermined timing, and the exposure of the film 11 is completed.

Step S13: After the exposure of the film 11, the body microcomputer 6 returns the quick return mirror 12 to the photographing optical path, winds up the film 11 by one frame, and enters a standby state for the next photographing. Thus, a series of shooting operations are completed.
(Effect of 1st Embodiment)
In the camera system of the first embodiment, the dimmable distance that is changed according to the shutter fully open time or the like is displayed on the display unit. Therefore, the user can easily grasp whether or not appropriate exposure can be realized under a certain shutter speed or aperture condition, and can obtain a photograph in good condition.

(Configuration of Second Embodiment)
FIG. 5 is a schematic diagram of the camera system 1a of the second embodiment (corresponding to the camera systems of claims 1, 2, and 4 and the flash device of claim 6). Note that in the second embodiment, identical symbols are assigned to configurations identical to those in the first embodiment and descriptions thereof are omitted.
A camera system 1a according to the second embodiment includes a camera body 2a that is a single-lens reflex electronic camera, and a flash device 3a attached to the camera body 2a. In the camera system 1a of the second embodiment, information on the necessary light emission amount is acquired by performing monitor light emission prior to the main light emission at the time of photographing.

  The camera body 2a includes an image sensor 30 as an imaging unit. Light receiving elements are two-dimensionally arranged on the light receiving surface of the image pickup element 30 facing the photographing lens system 8, and a subject image projected on the light receiving surface is photoelectrically converted by each light receiving element to generate an image signal. The output of the image sensor 30 is output to the image processing circuit via the A / D conversion circuit, and image data is generated by the image processing circuit (the A / D conversion circuit and the image processing circuit are not shown).

The image sensor 30 also has an electronic shutter function by controlling the charge accumulation time of each light receiving element. The body microcomputer 6 controls the charge accumulation time of the image pickup device 30 and obtains image pickup unit sensitivity information. In the case of an electronic shutter, “shutter time” corresponds to the shutter fully open time in the first embodiment.
Here, the electronic shutter is different from the first embodiment in that unevenness does not occur in the subject image even when the flash device 3 continues to emit light after the electronic shutter is closed. However, in the above case, image degradation may occur due to blooming or smear. Therefore, also in the second embodiment, the arithmetic control circuit 25 of the flash device 3 (1) when the light emission amount of the flash device 3 reaches the required light emission amount transmitted from the camera body 2a, or (2) shutter seconds. The light emission is stopped at any time when the permissible light emission time has elapsed.

  As shown in FIG. 6, in the second embodiment, it is preferable to set the “light emission allowance time” to be equal to or less than the shutter time (shutter fully open time). In the case of an electronic shutter, even if the flash device continues to emit light after the shutter time elapses, it does not contribute to an increase in exposure amount, but rather increases the risk of blooming or smearing. Of course, the “light emission allowable time” may be the shutter speed.

(Operation of Second Embodiment)
The camera system 1a of the second embodiment is configured as described above, and the operation thereof will be described below with reference to the flowchart of FIG.
Step S21: First, the user attaches the flash device to the camera body 2a, and then turns on the power switch 20 of the flash device 3 so that the flash device 3a can be used.

Step S22: The user performs a predetermined input, such as half-pressing the release button, to the camera body 2a. Then, the body microcomputer 6 of the camera body 2 a takes in the luminance information of the subject from the divided photometry unit 4. Then, the body microcomputer 6 performs an exposure calculation based on the luminance information, and determines an exposure condition (aperture value, shutter speed, etc.) at the time of shooting.
Step S23: The body microcomputer 6 transmits the aperture value, the shutter speed, and the imaging unit sensitivity information to the arithmetic control circuit 25 of the flash device 3a.

Step S24: The arithmetic control circuit 25 outputs the acquired shutter full open time to the storage unit 28. The storage unit 28 reads the data of the upper limit value of the effective light emission amount corresponding to the input shutter full open time, and outputs it to the arithmetic control circuit 25.
Step S25: The calculation control circuit 25 calculates the upper limit value of the dimmable distance from the acquired upper limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information. At the same time, the arithmetic control circuit 25 reads the lower limit value of the effective light emission amount, and calculates the lower limit value of the dimmable distance from the lower limit value of the effective light emission amount, the aperture value, and the imaging unit sensitivity information.

Step S26: The arithmetic control circuit 25 outputs the upper limit value and lower limit value of the dimmable distance, the imaging unit sensitivity information, and the aperture value to the display unit 29 and displays them on the display unit 29.
Step S27: The user confirms the display of the upper limit value and the lower limit value of the dimmable distance on the display unit 29, and determines whether to start photographing. When shooting is started (YES side), the process proceeds to the shooting operation in step S28. If shooting is not started (NO side), the process returns to step S22 to reset the shutter speed and aperture value.

  Step S28: The user presses the release button to start shooting. When the shutter release switch is pressed, the body microcomputer 6 instructs the arithmetic control circuit of the flash device 3a to perform monitor light emission. The body microcomputer 6 jumps up the quick return mirror 12 and evacuates from the photographing optical path prior to the monitor light emission. When receiving the monitor emission instruction, the arithmetic control circuit 25 sets the signal line TG to “H” to cause the xenon arc tube 23 to emit light at a predetermined emission intensity and perform monitor emission. The monitor light emission may be performed a plurality of times.

  Step S29: The photometry circuit 26 of the flash device 3a measures the light emission amount of the xenon arc tube 23 and notifies the calculation control circuit 25 of the measurement result. The arithmetic control circuit 25 sets the signal line STP to “H” to end the light emission of the xenon arc tube 23. The arithmetic control circuit 25 notifies the body microcomputer 6 of the camera body 2a of the end of monitor light emission and the guide number of monitor light emission.

  Step S30: On the other hand, during monitor light emission, the dimming metering section 5 of the camera body 2a measures the amount of reflected light of the subject that has passed through the photographing lens system 8 and is reflected by the curtain plane of the focal plane shutter 10, and Measure brightness. When the body microcomputer 6 receives the notification of the end of the monitor light emission, the body microcomputer 6 acquires the subject brightness from the light control metering unit 5. The body microcomputer 6 calculates the necessary light emission amount of the main light emission by a known calculation method in consideration of the shooting distance, the appropriate exposure value, and the sensitivity of the imaging unit. Then, the body microcomputer 6 notifies the calculation control circuit 25 of the flash device 3a of the necessary light emission amount for the main light emission.

Step S31: The body microcomputer 6 runs the front curtain of the focal plane shutter 10 to expose the image sensor 30. Then, the body microcomputer 6 causes the image pickup device 30 to start accumulating electric charges and sets the electronic shutter to the “open” state.
Step S32: The arithmetic control circuit 25 of the flash device 3a determines whether or not the light emission time capable of realizing the necessary light emission amount for the main light emission is equal to or shorter than the light emission allowable time. If it is less than the light emission allowable time (YES side), the process proceeds to step S33. If it is longer than the light emission allowable time (NO side), the process proceeds to step S34.

  Step S33: The arithmetic control circuit 25 sets the signal line TG to “H” in synchronization with the opening operation of the electronic shutter, and causes the xenon arc tube 23 to emit light. The arithmetic control circuit 25 sets the signal line STP to “H” when the light emission time of the required light emission amount has elapsed, and stops the light emission of the xenon arc tube 23. After the elapse of the shutter time, the body microcomputer 6 of the camera body 2a ends the charge accumulation of the image sensor 30 and puts the electronic shutter in the “closed” state.

  Step S34: The arithmetic control circuit 25 sets the signal line TG to “H” in synchronization with the opening operation of the electronic shutter, and causes the xenon arc tube 23 to emit light. The arithmetic control circuit 25 sets the signal line STP to “H” when the allowable emission time elapses, and stops the emission of the xenon arc tube 23. In this case, the light emitted from the xenon arc tube 23 is emitted at the upper limit of the effective light emission amount. After the elapse of the shutter time, the body microcomputer 6 of the camera body 2a ends the charge accumulation of the image sensor 30 and puts the electronic shutter in the “closed” state.

Step S35: The body microcomputer 6 returns the quick return mirror 12 to the photographing optical path, runs the rear curtain of the focal plane shutter 10, and enters a standby state for the next photographing. Thus, a series of shooting operations are completed.
(Effect of 2nd Embodiment)
Also in the camera system of the second embodiment, the dimmable distance that is changed according to the shutter fully open time or the like is displayed on the display unit as in the first embodiment. Therefore, the user can easily grasp whether or not appropriate exposure can be realized under a certain shutter speed or aperture condition, and can obtain a photograph in good condition.

(Third embodiment)
FIG. 8 is a flowchart showing the operation of the camera system of the third embodiment of the present invention (corresponding to the camera system of claims 1, 3, and 5 and the flash device of claim 7). The third embodiment is a modification of the first embodiment, and is the same as the first embodiment except that the calculation control circuit 25 functions as a shutter full-open time calculation unit. Description is omitted.

That is, in the third embodiment, the camera body 2 outputs the shutter time and shutter curtain travel time information to the flash device 3b, and the arithmetic control circuit 25 of the flash device 3 uses the shutter time and shutter curtain travel time information to determine the shutter. Calculate the fully open time. The calculation of the shutter fully open time is calculated by subtracting the shutter curtain travel time from the shutter time.
In the operation of the camera system of the third embodiment, steps S41 and S42 correspond to steps S1 and S2 of the first embodiment, and steps S43 and S44 are different.

  Here, in step S43, the body microcomputer 6 transmits the aperture value, shutter speed, shutter curtain travel time, and imaging unit sensitivity information to the arithmetic control circuit 25 of the flash unit 3. In step S44, the calculation control circuit 25 calculates the shutter fully open time by subtracting the shutter curtain travel time from the input shutter speed. The subsequent steps S45 to S54 correspond to steps S4 to S13 of the first embodiment.

(Supplementary items of the embodiment)
As mentioned above, although this invention has been demonstrated by said embodiment, the technical scope of this invention is not limited to the said embodiment. For example, in the first to third embodiments, an example of a camera system in which a flash device is externally attached to the camera body has been described. However, a camera system in which a flash device is built in the camera body may be used. Further, the photographing lens system and the diaphragm may be interchangeable independently from the camera body. Furthermore, in the camera system of the first embodiment or the third embodiment, the necessary light emission amount may be acquired by monitor light emission as in the second embodiment.

  The present invention is suitable for a camera system equipped with a flash device capable of controlling light emission stop when grasping a dimmable distance that is changed according to the shutter speed.

It is a schematic diagram of the camera system of a 1st embodiment. It is a figure which shows the issuing stop in the light emission permissible time of 1st Embodiment. It is a figure which shows the display screen of a display part. It is a flowchart which shows operation | movement of the camera system of 1st Embodiment. It is a schematic diagram of the camera system of 2nd Embodiment. It is a figure which shows the light emission stop in the light emission permissible time of 2nd Embodiment. It is a flowchart which shows operation | movement of the camera system of 2nd Embodiment. It is a flowchart which shows operation | movement of the camera system of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Camera system 2, 2a Camera main body 3, 3a Flashing device 4 Division | segmentation photometry part 5 Light control photometry part 6 Body microcomputer 7 Communication part 8 Shooting lens system 9 Aperture mechanism 10 Focal plane shutter 11 Film 12 Quick return mirror 13 Diffusion Screen 14 Condenser lens 15 Penta prism 16 Eyepiece lens 17 Photometric prism 18 Photometric lens 19 Power supply 20 Power switch 21 Capacitor 22 Booster circuit 23 Xenon arc tube 24 Light emission control circuit 25 Arithmetic control circuit 26 Photometry circuit 27 Receiver 28 Storage unit 29 Display unit 30 Image sensor

Claims (7)

An imaging mechanism having an imaging lens, a diaphragm, a shutter means, and an imaging unit;
A camera control unit that controls each unit of the photographing mechanism to obtain a necessary light emission amount, an aperture value of the diaphragm, a shutter fully open time of the shutter unit, and imaging unit sensitivity information;
A flash light emitting unit that emits flash light during photographing by the photographing mechanism;
A light emission control unit for stopping the light emission of the flash light emitting unit either at a time when the required light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time;
Effective light emission amount calculating means for calculating an upper limit value of the effective light emission amount due to light emission stop in the light emission allowable time;
Dimming for calculating a dimmable distance at which the flash light emitting unit is appropriately exposed based on the upper limit value of the effective light emission amount that changes according to the shutter fully open time, the aperture value, and the imaging unit sensitivity information Possible distance calculation means;
And a display unit for displaying the dimmable distance.   The camera system according to claim 1, wherein the imaging unit is an imaging device that photoelectrically converts a subject image, and the shutter unit is an electronic shutter. The shutter means is a focal plane shutter;
The camera system according to claim 1, wherein the camera control unit further acquires shutter second time information and shutter curtain travel time information of the shutter unit. The camera system according to claim 2 or 3, wherein the camera system includes a camera and a flash device that can be attached to the camera.
The camera includes the photographing mechanism, the camera control unit, and a communication unit that transfers the necessary light emission amount, the aperture value, the shutter full open time, and the imaging unit sensitivity information to the flash device,
The flash device includes a receiving unit that receives the aperture value, the shutter full open time, and the imaging unit sensitivity information transmitted from the communication unit, the flash light emitting unit, the light emission control unit, and the effective light emission amount calculation. A camera system comprising: means; a dimmable distance calculating means; and the display section. The camera system according to claim 3, wherein the camera system includes a camera and a flash device attachable to the camera.
The camera is configured to communicate the imaging mechanism, the camera control unit, the required light emission amount, the aperture value, the shutter time information, the shutter curtain travel time information, and the imaging unit sensitivity information to the flash device. With
The flash device includes a receiving unit that receives the shutter second time information, the shutter curtain travel time information, and the imaging unit sensitivity information transmitted from the communication unit, and the shutter second time information and the shutter curtain travel time information. A shutter full open time calculating means for calculating the shutter full open time, the flash light emitting section, the light emission control section, the effective light emission amount calculating means, the dimmable distance calculating means, and the display section. A camera system characterized by that. A flash device that is attached to a camera having a communication unit that transfers necessary light emission amount, aperture value, shutter full open time, and imaging unit sensitivity information, and constitutes a camera system together with the camera,
A receiving unit that receives the necessary light emission amount, the aperture value, the shutter fully open time, and the imaging unit sensitivity information from the communication unit;
A flash light emitting section for performing flash light emission;
A light emission control unit for stopping the light emission of the flash light emitting unit either at a time when the required light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time;
Effective light emission amount calculating means for calculating an upper limit value of the effective light emission amount due to light emission stop in the light emission allowable time;
Dimming for calculating a dimmable distance at which the flash light emitting unit is appropriately exposed based on the upper limit value of the effective light emission amount that changes according to the shutter fully open time, the aperture value, and the imaging unit sensitivity information Possible distance calculation means;
A flash unit comprising: a display unit that displays the dimmable distance. A flash device that is attached to a camera having a communication unit that transfers necessary light emission amount, aperture value, shutter time information, shutter curtain travel time information, and imaging unit sensitivity information, and constitutes a camera system together with the camera,
A receiving unit that receives the required light emission amount, the aperture value, shutter second time information, shutter curtain travel time information, and the imaging unit sensitivity information from the communication unit;
Shutter full open time calculating means for calculating the shutter full open time from the shutter second time information and the shutter curtain travel time information;
A flash light emitting section for performing flash light emission;
A light emission control unit for stopping the light emission of the flash light emitting unit either at a time when the required light emission amount is reached or at a light emission allowable time corresponding to the shutter full open time;
Effective light emission amount calculating means for calculating an upper limit value of the effective light emission amount due to light emission stop in the light emission allowable time;
Dimming for calculating a dimmable distance at which the flash light emitting unit is appropriately exposed based on the upper limit value of the effective light emission amount that changes according to the shutter fully open time, the aperture value, and the imaging unit sensitivity information Possible distance calculation means;
A flash unit comprising: a display unit that displays the dimmable distance.

Images