JP2761770B2 - Camera strobe control - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe control device for a camera having a built-in strobe whose light-emitting unit moves between a storage position and a light-emitting position.

“Prior art and its problems” In recent years, in consideration of ease of use, cameras with a built-in automatic light control strobe are increasing. In some cameras having such a built-in strobe, a light emitting portion of the strobe is supported by a support mechanism such as a retractable mechanism or a pop-up mechanism. There is one that moves to a light emitting position protruding from the main body.

Such a conventional strobe control device generally controls strobe light emission based on an exposure factor, for example, luminance information of a photometric subject, calculated shutter speed information, and the like. That is, if the brightness of the subject is lower than a certain value at the time of shooting, the light emitting unit is moved to the light emitting position to emit light, and then returned to the storage position. On the other hand, if the brightness of the subject is higher than a certain value, there is no need to emit a strobe, so that the flash is not emitted while the light emitting unit is held at the storage position.

However, in the conventional camera, when the release button is half-pressed, it is determined whether or not to use the flash, and when it is determined that the flash is used, the light emitting unit is moved to the light emitting position. Even without it, the light-emitting part moved and was very troublesome.

In the self-timer operation, it is determined whether or not the strobe is used at the start of the self-operation, and when it is determined that the strobe is used, the light emitting unit is moved to the light emitting position at this time.
There is a problem that the subject brightness at the time of actual exposure cannot be handled. When the release button is half-pressed, operations such as photometry and auto focus are performed. When the release button is fully pressed, the shutter runs during normal shooting, and exposure operations such as flash emission occur. Operation starts.

"Object of the Invention" The present invention has been made to solve such a problem of a conventional camera having a built-in strobe, and provides a strobe control device for performing a movement operation of a light emitting unit at more optimal timing. The purpose is to:

SUMMARY OF THE INVENTION To achieve this object, the present invention provides, in a camera with a built-in strobe, a support mechanism for movably supporting a light emitting portion of the strobe at a storage position and a light emitting position of a camera body;
A drive mechanism for moving the light emitting unit between the use position and the storage position via the support mechanism, a photometric unit for calculating an exposure factor when the first switch is turned on, and a strobe based on the exposure factor Strobe determining means for determining whether or not to perform the flash operation, exposure means for performing an appropriate exposure operation when the second switch is turned on, that the strobe determining means has determined that the strobe light is used, and that the second switch has been turned on. Control means for moving the light-emitting unit to the light-emitting position on the condition that this is the case.

According to this configuration, even when the strobe determining unit determines that the strobe is used, the light emitting unit does not jump to the light emitting position unless the release switch is turned on.

Further, in photographing in the self-timer mode, at a predetermined time immediately after the start of the self-operation and immediately before the exposure operation, the photometric means calculates an exposure factor, and the flash determination means makes a determination based on the exposure factor to determine that the flash is used. At this time, if the control means moves the light emitting unit to the light emitting position, the exposure is performed based on the brightness of the subject immediately before the exposure.

"Embodiments of the Invention" The present invention will be described below based on embodiments shown in the accompanying drawings. FIG. 1 is a schematic configuration diagram of a power retractable strobe to which the present invention is applied. FIG. 2 is a diagram showing a single-lens reflex camera equipped with a strobe control device of a camera of the present invention, in which a light-emitting unit is moved to a light-emitting position. FIG. 3 is a front view showing a state in which an external strobe is mounted, and FIG. 3 is a schematic configuration diagram of a strobe control device of the present embodiment.

At the upper part of the camera body 10 (at the upper part of the pentaprism 11), the strobe light-emitting part 12 is stored by a support mechanism in the storage part 10a in the camera body 10 (the position shown by the imaginary line). It is movably supported at a light emitting position (a position shown by a solid line) protruding from the storage portion 10a.
In the drawing, only the lever 13 constituting the support mechanism is shown.

The lever 13 has one end pivotally supported by the rear end of the light-emitting unit 12 via a shaft 13a, and the other end pivotally supported by a side wall of a housing 10a formed in the camera body 10 via a shaft 13b. One of the levers 13 is formed with a sector gear 14 centered on a shaft 13b. A pinion 17 of a strobe motor 16 as a drive mechanism meshes with the sector gear 14 via a gear train 15.
Therefore, the rotation of the strobe motor 16 is changed to the gears 17, 15, 14
The lever 13 is rotated in accordance with the rotation direction of the motor 16, and the strobe light emitting unit 12 moves between the storage position and the light emitting position.

Two limit switches 18 and 19 are provided between the lever 13 and the camera body 10, and are turned on (or off) when the light emitting unit 12 reaches the storage position and the light emitting position, respectively. The strobe motor 16 is controlled by the camera control circuit 20, and is stopped when the state of the switches 18 and 19 changes.

A pin 14a is implanted in the sector gear 14, and this pin 14a
An arc-shaped groove 1 formed on the camera body 10 and centered on an axis 13b.
It fits in 0b. The rotation angle of the sector gear 14 is restricted by the pins 14a and the arc-shaped grooves 10b. That is, the lever
The two rotation limit positions of the light emitting unit 13 are the light emitting position and the storage position of the light emitting unit 12, respectively.

Further, in the present embodiment, an overload detection circuit for the strobe motor 16 is provided, and when the movement of the light emitting unit 12 is prevented by an external force or the like, the overload detection circuit detects this and stops the strobe motor 16. Note that the overload detection circuit is included in the camera control circuit 20 in this embodiment. Further, when the stop of the normal strobe motor 16 is detected by the overload detecting means that the pin 14a comes into contact with the end of the arc-shaped groove 10b and the lever 13 cannot rotate from the light emitting position or the storage position earlier. May be performed.

Next, a circuit configuration of the flash control device of the present embodiment will be described. The camera control circuit 20 shown in FIG. 3 is a circuit for generally controlling all operations of the camera, and is usually constituted by a microcomputer. The camera control circuit 20 is connected to a photometric circuit 22 that amplifies the output of a photometric sensor 21 that receives the subject light and processes the output into a predetermined photometric signal. The camera control circuit 20 determines an exposure factor (subject luminance, shutter speed T _v , aperture value, camera shake limit shutter speed, etc.) by a predetermined algorithm based on a photometric signal from the photometric circuit 22 and information such as film sensitivity information. calculate. The camera control circuit 20, the photometric sensor 21, and the photometric circuit 22 constitute a photometric unit.

Further, the camera control circuit 20 reads the lens information from a lens ROM 23 (or CPU) provided in the mounted photographing lens by serial communication. The type of lens attached, focal length,
Know the minimum aperture value, open aperture value, etc. Here, the camera control circuit 20 functions as a lens information input unit. Note that the serial communication is performed through connection of a plurality of contacts provided on the mount unit 24.

Further, the camera controller 20 is connected to respective contacts of a hot shoe 26 to which an external flash 25 is mounted. When the external flash 25 attached to the hot shoe 26 has a communication function, the camera control circuit 20 inputs flash information from the external flash 25 via the hot shoe 26. The strobe information includes whether the strobe information is compatible with the camera body, that is, whether or not the light emitting unit 12 is prevented from being raised, whether or not the guide number or charging is completed. On the other hand, an external flash from the camera control circuit 20
To 25, a light emission permission signal, a trigger signal, a quench signal and the like are sent.

The distance measurement unit 27 includes a distance measurement sensor that converts a subject image formed by a photographing lens into a predetermined electric signal, and outputs a distance measurement signal necessary for measuring a subject distance (defocus amount) from the distance measurement sensor. Output. The camera control circuit 20 calculates an amount of defocus based on the distance measurement signal and the lens information, and performs an AF process for driving the focusing lens of the photographing lens to an in-focus position via the AF mechanism.

The LCD panel 29 is provided on the outer surface of the camera body 10 and in the finder field of view, and its display is controlled by the camera control circuit via the display circuit 28. LC of this embodiment
The D panel 29 displays at least whether or not the strobe can emit light. Of course, in addition to this, various displays relating to the photographing function of the camera, such as an exposure program mode, a shutter speed, an aperture value, and in-focus / out-of-focus, can also be performed.

The camera control circuit 20 includes, as switches, a photometric switch SWS as a first switch, a release switch SWR as a second switch, a self-switch SW1, a light-emission changeover switch SW2, a lens improper release switch SW3, and an up detection switch SW4. Is connected.

The photometry switch SWS and the release switch SWR are switches that are linked with the release button 31. The photometry switch SWS is turned on when the release button 31 is half-pressed, and the release switch SWR is turned on when the release button 31 is fully pressed. When the photometric switch SWS is turned on, the photometric circuit 22, the distance measuring unit 27, and the like start operating, and when the release switch SWR is turned on, the operation shifts to a release operation.

The self-switch SW1 is a switch for operating a self-timer. When the self-switch SW1 is turned on, a self-timer mode is entered. When the release switch SWR is turned on in the self-timer mode, a self-operation is started, and a release operation is performed after a lapse of a predetermined time.

The light emission switch SW2 is a switch for switching the light emission mode of the strobe. When the light-emission switch SW2 is not turned on, it controls whether or not to fire the strobe based on the luminance of the subject measured via the photometry circuit 22 and the lens information read from the ROM 23 (automatic light emission mode), and is turned on. When the flash is ON, the strobe is forcibly controlled to emit light (forcible light emission mode). If the calculated shutter speed is faster than the flash tuning speed at the time of forced flash emission, the camera control circuit 20 sets the shutter speed at the time of release to the flash tuning speed.

The lens improper release switch SW3 is a switch for switching whether or not the lens information read from the lens ROM 23 is used for determining the strobe light emission. The lens inappropriateness release switch SW3 is operated, for example, when it is necessary to forcibly emit light from the strobe, even though it is known that the angle of view of the attached lens is wider than the irradiation angle of the strobe.

The up detection switch SW4 is a switch that is turned on when the light emitting unit 12 of the strobe light shown in FIG. 1 is completely up (when the light emitting position is reached).
Note that the same switch can be used for both the up detection switch SW4 and the limit switch 19.

In addition, the camera control circuit 20 includes a strobe (arc tube 36)
A strobe circuit 35 for emitting light is connected to an auxiliary light emitting LED 37 provided adjacent to a light emitting tube 36. The camera control circuit 20 outputs a light emission permission signal, a trigger signal, and a quench signal to the strobe circuit 35. Here, the camera control circuit 20 functions as a flash control unit.

The above-mentioned light emission permission signal is a signal for permitting light emission when the conditions under which the strobe light can be emitted are established, and the internal and external strobes receiving this signal start preparation for light emission such as charging. The trigger signal is a signal for causing the strobe to emit light, and the quench signal is a signal for stopping the light emission when the amount of light emitted by the strobe reaches an appropriate amount. The auxiliary light emitting LED 37 assists the distance measurement by the distance measurement circuit 27 by irradiating a contrast pattern to the object when the object has low luminance or low contrast.

The camera control circuit 20 further includes a release switch SWR
Release magnet 39 that releases the mechanical charge of the mirror and shutter curtain (front curtain and rear curtain) when is turned on
A front curtain magnet 40 that locks the front curtain and the rear curtain in place of the mechanical lock, and sequentially releases the locking to move the front curtain and the rear curtain so as to obtain a predetermined shutter speed. And the rear curtain magnet 41 are connected.

The X contact switch SWX in the figure is a switch for emitting an external flash having a low function (having no communication function), and is turned on after the front curtain has been driven, thereby turning on the external flash via the hot shoe 26. Flash.

The strobe control device for a camera according to the present invention thus configured operates as follows based on the operation flowcharts shown in FIGS. 4 and 5. Here, before describing this flowchart, the schematic operation of the above-described apparatus will be described.

In the camera strobe control device according to the present invention, the calculated shutter speed is lower than a certain value (for example, lower than the camera shake limit shutter speed), an auxiliary light by the strobe is required, and the photographing lens attached to the camera is used. When the release switch SWR is turned on, the light emitting unit 12 emits light for the first time and emits light when the release switch SWR is turned on.

In the case of forced light emission, if the calculated shutter speed is higher than the flash tuning speed, the flash tuning speed is set.

Also, if you turn on the lens inappropriate release switch SW3,
Regardless of the mounted photographing lens, the above-mentioned strobe control is performed based only on the luminance of the photometric subject. And it is provided on the camera body 10
The LCD panel 29 displays whether or not strobe light emission is possible, that is, whether or not the characteristics of the mounted photographing lens match the characteristics of the strobe, whether or not the external strobe 25 is appropriate, and the like.

The outline of the operation is as described above, but the operation of the present embodiment will be described in detail below with reference to the flowcharts shown in FIGS. This operation is performed by the camera control circuit.
It is executed based on the program written in the memory by 20 microcomputers.

First, when a program starts under a predetermined condition such as turning on a main switch, the camera control circuit 20 inputs switch information (whether it is ON or OFF) of each of the switches SWS, SWR and SW1 (step S1). Then, it waits for the photometric switch SWS to be turned on (S3).

When the metering switch SWS is turned on, the light emission switch SW2
Switch information, and if the switch is on, the flash mode is set to the forced flash mode. If the switch information is off, the flash mode is set to the automatic flash mode (S5 to S1).
1). When the strobe light emission mode is set to the forced light emission mode, the shutter speed at the time of release is set to a speed synchronized with the light emission of the strobe light, and the strobe light is emitted at the time of release. On the other hand, when the automatic light emission mode is set, the camera control circuit 20 reads the lens information stored in the lens ROM 23 and exchanges information with the external strobe 25 via the hot shoe 26 by the control described later. (S13, S15). The lens information stored in the lens ROM 23 is information such as a lens type and a focal length. Information from the external strobe 25 includes characteristics of the external strobe 25, for example, whether or not movement of the light-emitting unit 12 to the light-emitting position when attached to the camera body 10 is prevented, or a guide number. When an external strobe having no communication function is mounted, it is detected that the external strobe is mounted based on the level of an electric contact having a hot shoe.

Then, the camera control circuit 20 calculates an exposure factor such as a shutter speed based on the photometric signal output from the photometric circuit 22, the film sensitivity information and the like (S17, S19).

Next, the camera control device 20 causes the LCD panel 29 to display various set values set in the camera via the display circuit 28 (S21). This display content includes a strobe light emission mode.

Then, the camera control circuit 20 checks whether or not the self-switch SW1 is turned on (whether or not the camera is in a self-timer mode) (S23). (S2
4) If the self-operation is not being performed, it is checked whether or not the release switch SWR is on (S25). If the release switch SWR is on, the self-counter is started, that is, the self-operation is started (S26). Then, the fact that the operation is started in the self-timer mode is indicated by blinking of the external LED 32 (see FIG. 3), and the self-counter is further decremented (S27, S29). Step S24
If the self-operation has already started, the process jumps to step S27 to continue the self-operation. If the release switch SWR is not turned on even in the self-timer mode, the process returns from step S25 to step S1.

Then, it is checked whether or not the self-counter has become 0. If it is not 0, the process returns to step S1 to repeat the above-mentioned process, and if it becomes 0, the process proceeds to step S33 (S3
1).

On the other hand, if the mode is not the self-timer mode, that is, if the mode is the normal shooting mode, the process proceeds from step S23 to step S32, where it is checked whether the release switch SWR is on. If the release switch SWR is not turned on, the process returns to step S1 and returns to steps S1 to S4.
Repeat the processing of S23 and S32, release switch SWR
Is turned on, the process proceeds to step S33.

In step S33, it is checked whether or not the calculated shutter speed is lower than a predetermined speed (for example, a camera shake limit shutter speed). If the calculated shutter speed is not low, there is no need for auxiliary light emission and strobe light emission. )
Fly to processing.

On the other hand, if the calculated shutter speed is low, it is checked whether an external strobe is attached (S3).
Five). Step S if no external strobe is attached
Proceeding to step 39, if it is attached, proceed to step S37 to check whether the characteristics of the external strobe are compatible. If it is, return to step S39; otherwise, skip to step S45. Here, the adaptation of the external flash means that it does not prevent the light emitting unit 12 from being raised to the light emitting position.

In step S39, a light emitting unit up process of moving the light emitting unit 12 to the light emitting position is performed, and the up detecting switch SW4
Is turned on (when the light-emitting part 12 is raised to the light-emitting position), the auxiliary light-emitting LED 37 is turned on, and then the AF processing in step S45 is performed. If the up detection switch SW4 is not turned on, the light is emitted and the AF processing is performed. Go on (S41, S43).

In step S45, the distance to the subject is measured via the distance measurement unit 27, and the focusing lens (not shown) of the photographing lens is moved to the focus position by the AF mechanism based on the distance measurement value (defocus amount). Perform AF processing. If the subject is in focus by the AF process, the process proceeds to the next step S49. If the subject is not focused, the process returns to step S1 and repeats the above process until the subject is focused (S47).

In the self-timer mode, the processes of steps S1 to S23, S24 to S31, S33 to S47, and S1 are repeated until the self-counter becomes 0 and focus is achieved. On the other hand, in the normal photographing mode, the processing of S1 to S23, S32 to S47, and S1 is repeated from when the release switch SWR is turned on until focusing is achieved. Note that the above is the case of focusing priority. However, in the case of release priority, step S4
The process advances from step 7 to step S49.

In step S49, it is checked whether the flash mode is set to the forced flash mode. If the flash mode is the forced flash mode, the built-in flash is fired regardless of the taking lens and the external flash.
The process jumps to S61, and if not in the forced light emission mode, the process proceeds to step S51.

In step S51, it is checked whether the calculated shutter speed is lower than a predetermined speed. If the speed is not low, the strobe is not fired, so the flow jumps to step S77 to inhibit the strobe light emission, set the shutter speed at the time of release to the calculated shutter speed, and then perform the exposure process of step S69.

If the calculated shutter speed is lower than the predetermined speed, the strobe is fired, so it is first checked whether an external strobe is attached (S53). If an external flash is attached, it is checked whether the external flash is compatible (S54). If the external flash is not compatible, the light emitting unit 12 cannot move to the normal light emitting position. The light emission of the built-in flash is prohibited, and the shutter speed at the time of release is set to the flash synchronization speed, and then the exposure processing in step S69 is performed.

If the external strobe is compatible, it is checked whether the characteristics of the mounted photographic lens match the characteristics of the built-in flash (S55). If not,
Since normal irradiation cannot be performed even when the built-in strobe light is emitted, the process proceeds to step S75 where the built-in strobe light emission is prohibited. On the other hand, if they match, in step S56,
Enable the built-in flash and set the shutter speed at release to the flash sync speed, then step
The process proceeds to S63.

If it is determined in step S53 that there is no external flash in the external flash presence check, it is checked whether the attached photographing lens is compatible (S57). If so, the process proceeds to step S61, and if not, it is checked whether the lens improper release switch SW4 is on (S59). If the lens improper release switch SW4 is not turned on, the built-in flash is not fired, so the process proceeds to step S77.If it is turned on, the built-in flash is fired.
Return to S61.

In step S61, light emission of the built-in flash is permitted, and the shutter speed at the time of release is set to the flash synchronization speed. Then, it is checked whether or not the up detection switch SW4 is turned on, that is, whether or not the light emitting unit 12 is at the light emitting position. If not, the strobe motor 26 is activated to raise the light emitting unit 12 to the light emitting position. After that, it is checked again whether the up detection switch SW4 is turned on (S63, S65, S67).

When the up detection switch SW4 is turned on, step S61
The exposure process is performed under the conditions set in (or steps S56, S75, S77) (S69).
If it is up, it is brought down and the process ends (S71).

On the other hand, in the up processing of the light emitting unit 12 (S65), if the light emitting unit 12 does not rise to the light emitting position for some reason and the up detection switch SW4 is not turned on, the process proceeds from step S67 to step S73.

In step S73, the presence or absence of an external flash is checked.
In step S77, the emission of the internal and external strobes is prohibited, the shutter speed at the time of release is set to the calculated shutter speed, and the exposure process is performed without emitting the internal and external strobes (S6).
9). On the other hand, if an external flash is attached, the built-in flash is prohibited in step S75, the shutter speed at the time of release is set to the flash tuning speed, and then the external flash is fired to perform exposure processing ( S69).

When the exposure process is completed, if the light emitting unit 12 has been raised to the light emitting position, the light emitting unit 12 is lowered to the storage position and the process ends (S71).

FIG. 5 shows a display subroutine. Light emitting unit
When it is determined that 12 is not in the flash position,
When 25 is determined to be inappropriate or when the mounted lens is determined to be inappropriate, a warning is displayed (S81 to S87). The determination that the light emitting unit 12 is not at the light emitting position is made by turning the up detection switch SW4 ON / OFF as described above.
Detected by OFF.

Further, in the display subroutine, the four types of light emission modes of the above-mentioned strobe light and the setting information of the camera are displayed (S89).

As described above, in the present embodiment, it is determined whether or not to use strobe light based on the subject luminance and the lens information. When the strobe light is required, the light emitting unit 12 is automatically raised immediately before the exposure to perform the exposure accompanied by the strobe light during the self-timer operation on condition that the release switch SWR is turned on during the normal photographing. Therefore, simply turning on the photometric switch SWS does not cause the light-emitting unit 12 to protrude to the light-emitting position, so that there is no trouble. Moreover, since the sound of the light-emitting unit 12 rises and the sound of the release operation,
Eliminating auditory annoyance.

Then, at the time of the self-timer operation, it is determined whether or not the strobe is used by the photometry immediately before the release operation, and the light-emitting unit 12 is protruded to the light-emitting position, so that a more accurate exposure value can be photographed.

[Effects of the Invention] As is clear from the above description, according to the camera strobe control device of the present invention, during normal shooting, the light emitting unit is moved to the light emitting position after the release switch is turned on.
The number of times the light emitting unit is up and down is reduced, so that troublesome shooting is eliminated, and operability is improved.

In addition, at the time of self-timer shooting, whether or not to use a flash is determined immediately before the release operation to perform exposure, so that shooting can be performed with a more accurate exposure value.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a retractable strobe whose operation is controlled by a camera strobe control device of the present invention, and FIG. 2 is a single-lens reflex camera equipped with a camera strobe control device of the present invention. FIG. 3 is a front view showing a state in which a light emitting unit is moved to a light emitting position and an external strobe is mounted. FIG. 3 is a schematic configuration diagram showing a circuit configuration of an embodiment of a strobe control device for a camera according to the present invention. 4A, 4B, 4C and FIG. 5 are operation flowcharts of the embodiment. 10 camera body, 12 light emitting unit, 13 lever (supporting mechanism), 16 strobe motor (drive mechanism), 20 camera control circuit (photometric means, strobe determining means, control means), 21
... A photometric sensor (photometric means), 22 a photometric circuit (photometric means), 23 lens ROM, 28 a display circuit, 29 an LCD panel (display means).

Claims (3)

(57) [Claims] 1. A camera having a built-in strobe, a support mechanism for movably supporting a light-emitting portion of the strobe at a storage position and a light-emitting position of a camera body, and using the light-emitting portion via the support mechanism. A drive mechanism for moving between a position and a storage position, photometric means for calculating an exposure factor when the first switch is turned on, and strobe determining means for determining whether or not to use a strobe based on the exposure factor. An exposure unit for performing a predetermined exposure operation when a second switch is turned on; and a light emitting position for the light emitting unit on the condition that the strobe determining unit determines that a strobe is used and that the second switch is turned on. And a control means for moving the strobe light to the camera. 2. The camera according to claim 1, wherein said camera has a self-timer mode. In the photographing in said self-timer mode, at a predetermined time immediately after the start of the self-timer operation and immediately before the exposure operation, said photometric means is operated to expose said camera. A flash control means for a camera, wherein the control means moves a light emitting portion to a light emitting position when a factor is calculated and the flash determining means determines to use the flash based on the exposure factor. 3. The camera control device according to claim 1, further comprising display means for displaying when the strobe determining means determines that the strobe light is emitted.