JPH09325388A - Camera capable of controlling emitted strobe light quantity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a proper strobe exposure for each object, even if plural objects are arbitrarily arranged in a range direction in a picture by controlling the light quantity of the flat light emission of a stroboscope device, in response to plural bits of distance information, plural bits of photometric information and the clocking output of a timer means. SOLUTION: When a first release switch is turned on, multipoint range-finding is attained by a range-finding circuit 17. Bits of subject distance information located at plural range-finding points in the traveling direction of the curtain of a focal plane shutter in a photographic picture are obtained through the multipoint range-finding. Continuously, division photometry is attained by a photometric circuit 18. Bits of luminance information for plural regions divided in the traveling direction of the curtain of the focal plane shutter in the photographic picture are obtained through this division photometry. Then, a stop value and a shutter speed when a film is exposed are calculated with film sensitivity information, plural bits of distance information and plural bits of luminance information, to set the flat light emission pattern of the stroboscope device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera used together with a strobe device, and more particularly to a camera having a focal plane shutter for controlling the light emission condition of a flat light emission strobe device according to the photographing condition.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for controlling the light emission form of a strobe device. For example, in Japanese Examined Patent Publication No. Sho 61-19021, a liquid crystal plate is arranged in front of the light emitting portion of the strobe device, and the light transmittance of a portion of the liquid crystal plate corresponding to a short-distance subject is controlled so as to decrease
It is shown that appropriate stroboscopic light is emitted to any of the objects mixed in perspective.

Further, Japanese Patent Laid-Open No. 4-225337 is provided with two or more light emitting portions having different irradiation light distributions, and superimposing them while controlling the light amounts of the respective light emitting portions so that they are suitable for both distant and near mixed objects. It is shown that the flash light is emitted.

[0004]

However, since the light of the Japanese Patent Publication No. 61-19021 is dimmed by the liquid crystal plate, it is considered that the light amount loss is large and the liquid crystal plate is damaged by the heat generated from the light emitting portion. In addition, JP-A-4-
In the case of 225337, since it is necessary to provide a plurality of light emitting units, it is difficult to achieve miniaturization of the device, and in principle, the subject is near, middle, and far from the left to the right of the screen. It is convenient if the subjects are arranged so that the subject distance increases or decreases uniformly, but it is considered difficult to handle when the subjects are arranged irregularly such as near, far, and middle. To be

The present invention has been made in view of the above-mentioned disadvantages, and even if a plurality of subjects are arbitrarily arranged in the distance direction within the screen as long as the stroboscopic irradiation is possible, the respective subjects are properly arranged. It is an object of the present invention to provide a camera capable of stroboscopic light exposure and capable of controlling the stroboscopic light emission amount for a subject at infinity to a minimum.

[0006]

In order to solve the above-mentioned problems, a camera capable of controlling the strobe light emission amount of the present invention comprises a shutter device for slit exposure, a flat light emission strobe device with a variable light emission amount, and an on-screen photographing screen. Multi-point distance measuring means for measuring the distances to a plurality of objects to be photographed distributed in the area, divided photometric means for measuring each of a plurality of divided areas of the photographing screen, and timekeeping for measuring the elapsed time from the start of the slit exposure. Means and a plurality of distance information obtained by the distance measuring means at the time of the slit exposure, a plurality of photometric information obtained by the divided photometry, and the strobe device in response to the timing output of the timing means. And a control means for controlling the flat emission light amount.

Further, in the camera capable of controlling the amount of stroboscopic light emission according to the present invention, the advancing direction of the slit exposure coincides with the dividing direction of the distance measuring and photometric regions. Further, in the strobe light emission amount controllable camera of the present invention, the control means increases the flat light emission light amount according to the distance when the distance to the object in the photographing screen is a predetermined value or less and When it is far from the predetermined value, the amount of flat emission light is minimized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block configuration of an embodiment of a camera capable of controlling a strobe light emission amount according to the present invention, in which a strobe device is incorporated. The timer means 10 for measuring the elapsed time from the start of traveling of the focal plane shutter 14, which will be described later, is connected to the control means 19, and the strobe light emitting section 11 is connected to the strobe circuit 12 capable of flat light emission control. The strobe circuit 12 is connected to the control means 19.

A film feeding means (not shown) for feeding the film 13 loaded in the camera, and two films arranged in the vicinity of the film exposure surface for controlling the exposure time are arranged in the longitudinal direction of the film screen. The focal plane shutter 14 on which the curtain travels, and this focal plane shutter 14
A diaphragm 15 arranged between the lens and the taking lens 16 is connected to the control means 19, respectively.

Further, a multi-point distance measuring circuit 17 for measuring a subject distance at a plurality of distance measuring points along the curtain traveling direction of the focal plane shutter 14, and a photographing screen along the curtain traveling direction of the focal plane shutter 14. A multi-point photometric circuit 18 for measuring the brightness in a region divided into a plurality of areas is connected to the control means 19, respectively.

The time measuring means 10 measures the elapsed time from the start of traveling of the focal plane shutter 14 during film exposure, and the time measuring result is referred to by the control means 19. The strobe light emission unit 11 is controlled by the strobe circuit 12 and can perform so-called flat light emission in which light emission of a small amount of light is repeated during the traveling time of the shutter curtain of the focal plane shutter 14.

The film 13 loaded in the camera is controlled to be fed by a film feeding means (not shown), and the light flux from the subject is passed through the taking lens 16, the diaphragm 15 and the focal plane shutter 14 to the film exposing section. Reach The distance measuring circuit 17 measures the object distance at a plurality of measurement points along the curtain traveling direction of the focal plane shutter 14 in the photographing screen, and the photometric circuit 18 measures the focal plane shutter 14 in the photographing screen. The brightness of a plurality of areas divided along the curtain running direction is measured.

FIG. 2 shows the strobe light emitting section 11, the strobe circuit 12, and a part of the control means 19, and particularly shows the strobe circuit 12 in detail. The CPU (central processing unit) 1 to which the power VDD is applied is shown in FIG.
The first release switch SW1 and the second release switch S.
W2 and each are connected.

The power supply filter 2 including the diode D1 and the capacitor C1 is connected between the battery E1 and the CPU1. The booster circuit 3 includes a series circuit of resistors R1 and R2,
Transistors Q1, Q2 connected in parallel with the battery E1,
And a resistor R4, a diode D2, a capacitor C2, and a step-up transformer T1 connected in parallel, and a transistor Q3 connected to the primary side of the step-up transformer T1.
The resistor R3 connected between the transistor Q3 and the resistor R4, the resistor R5 connected to the secondary side of the step-up transformer T1 and the diode D3 constitute the structure as shown.

The voltage detecting circuit 4 is a voltage dividing circuit for measuring the voltage VMC of the main capacitor C5, which will be described later, of the boosting circuit 3 by the CPU 1, and is a series circuit of resistors R6 and R7, and in parallel with this series circuit. Connected capacitor C4, this capacitor C4 and main capacitor C5
And a diode D4 connected between
The divided output of the voltage VMC of the main capacitor C5 is VST
Is input to CPI1.

The trigger circuit 5 is a strobe light emitting section 11 shown in FIG.
Is a circuit for starting the light emission of the discharge tube 6 which is
The resistors R8 to R10 and the thyristor SCR1, the capacitors C6 and C7, the resistor R11, and the trigger transformer T2.
And are connected as shown. A STRG signal for instructing the start of light emission from the CPU 1 is applied to one end of the resistor R8.

One end of the discharge tube 6 is connected to the main capacitor C5, and the other end is connected to a part of the trigger circuit and the anode (anode) of the diode D5. Diode D5
The cathode (cathode) is connected to the collector of a known IGBT (insulated gate bipolar transistor) 7 which is a power switching element. A buffer circuit U1 controlled by the SCONT signal from the CPU 1 is connected to the gate which is the control electrode of the IGBT 7.

The IGBT 7 is capable of on / off control of a large current by a signal SCONT applied to a gate terminal which is a control electrode, and a satisfactory switching characteristic can be obtained even if the gate control voltage has a low voltage amplitude. The buffer circuit U1 may be omitted as long as the specifications are satisfied. Referring to the timing chart of FIG. 3,
The operation of this strobe device will be described. When the CPU1 sets the CHG signal instructing the start of boosting to the low level (a),
The booster circuit 3 starts to operate, and the boosted voltage VMC is charged in the main capacitor C5 (b). The voltage VST obtained by dividing the charging voltage VMC by the voltage detection circuit 4 is monitored by the CPU 1, and when the voltage VST reaches a predetermined voltage (c), the CPU 1 returns the CHG signal to a high level to stop the boosting operation. The above is the light emission preparation (charging) operation.

Then, in response to the light emission start signal from the camera, the CPU 1 outputs a pulse train to the SCONT signal, and at the same time when the pulse train starts, outputs a single trigger signal STRG. It should be noted that the figure (g) shows t of the SCONT signal.
2 is a partially enlarged view of FIG. By giving such a control signal, the discharge tube 6 is excited by the trigger circuit 5 to start light emission, and the IGBT 7 is turned on / off at the same frequency as the SCONT signal. Once the discharge tube 6 is in an excited state, the discharge tube 6 is an IGB that is a series switch within a predetermined time.
Small light emission can be repeated without giving a trigger signal again by simply turning T7 on and off at high speed.
A substantially flat light emission is possible only by controlling the NT signal.

The flat light emission is a light emission state in which a small amount of light is repeatedly emitted for a predetermined time, and the amount of flat light emission can be controlled by changing the duty ratio of the light emission control pulse SCONT signal during the flat light emission. As will be described later, the SCO
The duty ratio of the NT signal is changed. Next, the actual camera operation will be described with reference to FIG. This camera first determines whether or not a first release switch SW1 linked with a release member (not shown) is turned on (S1). If the first release is turned on, the distance measuring circuit 17 performs multipoint distance measurement ( S2). In this multi-point distance measuring, a plurality of distance measuring points along the traveling direction of the curtain of the focal plane shutter are measured within the photographing screen, and subject distance information located at each distance measuring point is obtained.

Subsequently, divided photometry is performed by the photometry circuit 18 (S3). This division photometry obtains luminance information of a plurality of areas divided along the curtain traveling direction of the focal plane shutter within the shooting screen. This camera calculates an aperture value and a shutter speed at the time of film exposure based on film sensitivity information by a film sensitivity input means (not shown), the plurality of distance information, and the plurality of luminance information (S
4) Further, based on this result, the flash emission amount is set so as to change the flat emission pattern of the flash device, that is, the flat emission light amount according to the slit traveling of the focal plane shutter (S5).

The flat emission pattern of the strobe device will be described with reference to FIGS. FIG.
(A) shows a photographing screen, (b) shows the change of the light emission amount with respect to the time of flat light emission, the solid line shows the example of the present embodiment, and the broken line shows the example of conventional flat light emission. FIG. 5C shows a traveling state of the lateral traveling type focal plane shutter. Here, FIG.
(C) corresponds to each other temporally and positionally.

Now, as shown in FIG. 5 (a), when a group of subjects having different distances is photographed by using a flat flash, a conventional flash light emitting unit emits flat light as shown by a broken line in FIG. 5 (b). Is almost constant, so for example
If the flat light emission amount is set so that the subject at the middle distance located on the left side of the screen is appropriate, the far-distance subject in the center of the screen and the short-distance subject on the right side of the screen will be underexposed and overexposed, respectively.

In order to avoid such a trouble phenomenon, in the present invention, the amount of flat light emission is controlled in synchronization with the progress of slit exposure of the focal plane shutter according to the object distance information, as indicated by the solid line in FIG. 5 (b). , When the slit of the shutter exposes a medium-distance subject, it emits a medium amount of flat emission light, and when the slit exposes a subject of a long distance, it emits a large amount of flat emission light, and the slit emits a short-distance subject. By controlling so that flat light emission with a small amount of light is performed during exposure, appropriate exposure amounts are given to subjects at different distances.

FIG. 6 shows an example in which three-point distance measurement is performed as the multi-point distance measurement, and FIG. 6A shows a photographing screen. Reference numerals 1 to 3 in the figure denote respective distance measuring points, and these distance measuring points are set by a distance measuring optical system (not shown). Since the distance information from each distance measuring point can be obtained, in order to properly control the exposure amount, the photographing screen is displayed as shown in FIG.
(B) is divided into areas A to C, and the flat emission light amount is set for each area.

FIG. 7 shows how the focal plane shutter 14 travels. Since the size of the exposure opening and the shutter curtain speed are known, the lines A to 6 shown in FIG.
For each area of C, from the timing t0 when the shutter front curtain reaches the exposure opening to the first timing t.
1 corresponds to the area A, the timing t1 to the second timing t2 correspond to the area B, and the timing t2 to the third timing t3 correspond to the area C.
It is possible to make the amount of flat emission light correspond to each region of A to C by controlling the time from the start of flat emission. The timing of these t0 to t3 is
The control of the flat light emission pattern is achieved by referring to the output of the timing means 10 and by changing the duty ratio of the SCONT signal during the flat light emission.

Returning to FIG. 4, when the flat light emission pattern is determined as described above, the CPU 1 determines the input of a second release signal SW2 which is an exposure start signal and is interlocked with a release operating member (not shown) (S6), and the second release signal SW2 is input. If the release is not on, the state of the first release is determined (S7). If the first release is not on, the process returns to S1, and if it is on, the process returns to S6 to wait for the second release to be turned on.

When it is determined that the second release is on, the procedure moves to the next step, the diaphragm 15 is driven (S8), the focal plane shutter 14 starts to run, and the timekeeping means 10 is started ( S
9), while the focal plane shutter 14 is traveling, flat light emission is performed according to the light emission pattern set in step S5 (S10). When the shutter travel is completed (S
11) End the control.

In this embodiment, the laterally-traveling type focal plane shutter is used, but a vertically-traveling type focal plane shutter may be used, and further, any slit exposure that allows uniform traveling is possible. This type of shutter device may be used. However, it is necessary to match the arrangement direction of the multi-point distance measurement points and the arrangement direction of the divided photometry areas with the slit traveling direction of the shutter device. Further, the camera having the built-in strobe device has been described, but the strobe device may be an external device as long as the flat emission light amount can be controlled by the camera.

According to the present embodiment, it is possible to properly expose a plurality of subjects arranged arbitrarily within the photographing screen. Further, the flat emission light amount is, for example, as shown in FIG.
It may be controlled as shown in. That is, FIG. 8 shows a case in which the background on the left side of the shooting screen is almost infinity, and this portion does not contribute to the exposure amount even if the strobe is irradiated, and the main subject is located on the right side of the shooting screen. In this example, the flat emission light amount is set to zero or the minimum level at the timing when the slit of the focal plane shutter corresponds to the infinity portion, and the flat emission light amount is increased and exposure is performed only at the timing corresponding to the main subject portion.

As described above, when the subject is at a long distance where the stroboscopic light cannot reach, the amount of the flat light emission is minimized and the main subject portion is irradiated with the flat light emission to prevent wasteful energy loss of the strobe device. ,
Efficient flat light emission is possible. The embodiment described above includes the following configurations. (1) Focal plane shutter, illumination means for illuminating an object while the focal plane shutter is running, distance measuring means capable of measuring a plurality of object distances, and a plurality of objects measured by the distance measuring means Depending on distance
A camera capable of controlling a strobe light emission amount, comprising: a light amount control means for changing a light amount of the illumination means while the shutter is traveling. (2) The focal plane shutter, the strobe circuit capable of emitting flat light, the distance measuring means capable of measuring a plurality of object distances, and the flat light emission according to the plurality of object distances measured by the distance measuring means. And a light amount control means for changing the luminance per unit time while the shutter is traveling, and a strobe light emission amount controllable camera. (3) The strobe light emission amount controllable camera according to (2), wherein the light amount control means increases the light emission luminance value as the subject distance increases. (4) The strobe light emission amount controllable camera according to (2), wherein the light amount control means sets the emission luminance to zero or a minimum value when the subject distance is longer than a predetermined value.

[0032]

As described above, according to the present invention,
By controlling the flat emission light amount during slit exposure in association with the distances of a plurality of subjects within the shooting screen, each subject can be properly exposed. Also, by minimizing the amount of flat light emitted for infinity,
It is possible to effectively irradiate the main subject within the effective strobe distance with the strobe light, and it is possible to achieve highly efficient flat light emission while suppressing unnecessary energy loss.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

FIG. 2 is a circuit example of a flash device according to the present embodiment.

FIG. 3 is a time chart showing the operation of the circuit of FIG.

FIG. 4 is a flowchart showing a schematic operation of the camera of the present invention.

FIG. 5 is a diagram showing a relationship between strobe light amount control according to a subject distribution state and traveling of a focal plane shutter.

FIG. 6 is an explanatory diagram of three-point distance measurement.

FIG. 7 is a diagram showing the relationship between the traveling timing of the focal plane shutter and the screen area.

FIG. 8 is a diagram showing a relationship between an example of an arrangement of subjects different from that in FIG. 5 and strobe light amount control according to the example.

[Explanation of symbols]

 1 CPU, 2 power supply filter circuit, 3 booster circuit, 4 voltage detection circuit, 5 trigger circuit, 6 discharge tube, 7 IGBT.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03B 15/03 G03B 3/00 A

Claims (3)

[Claims] 1. A shutter device for slit exposure, a flat flash device with variable light emission amount, a multi-point distance measuring means for measuring distances to a plurality of photographing objects distributed in the photographing screen, and an inside of the photographing screen. Divided photometric means for photometrically measuring each of a plurality of divided areas, timing means for timing the elapsed time from the start of slit exposure, and at the time of slit exposure, at least a plurality of distance information obtained by the distance measuring means, A camera capable of controlling a flash light emission amount, comprising: a plurality of photometric information obtained by divided photometry, and control means for controlling a flat light emission amount of the strobe device in response to a time output of the time measuring means. . 2. The camera according to claim 1, wherein a direction in which the slit exposure progresses and a direction in which the distance measurement and the photometry area are divided coincide with each other. 3. The control means increases the flat emission light amount according to the distance when the distance to the object in the photographing screen is less than or equal to a predetermined value, and flat when the distance is farther than the predetermined value. The camera according to claim 1, wherein the amount of emitted light is minimized.