JPH0915688A - Camera provided with synchronous photographing mode - Google Patents

Abstract

PURPOSE: To surely detect the synchronous timing of a trailing curtain by the microcomputer of an electronic flashing device through an interrupting function. CONSTITUTION: In this camera provided with a preceding curtain travel detecting means 1 detecting the completion of the traveling of the shutter preceding curtain of a focal plane shutter consisting of the shutter preceding and trailing curtains, a signal delaying means 2 for delaying the detection output of the preceding curtain travel detecting means 1 by a specified time, a flashing device 10 for executing flash photographing and further, a synchronous photographing mode for executing the flash photographing in connection with the traveling of the focal plane shutter, a mode selecting means 3 selecting a first or second trigger mode and a trigger control means 4 which triggers the flashing device 10 in synchronization with the shutter preceding curtain, when the first trigger mode is selected and the detection output of the detecting means 1 is detected and the flashing device 10, when the second trigger mode is selected and both of the detection output of the detecting means 1 and the output of the signal delaying means 2 are detected are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a synchronized photographing mode.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 61-156241 and US
As disclosed in P4,717,934,
There are detection means for detecting the traveling of the shutter front curtain and signal generating means for generating a signal after a predetermined time has elapsed from the start of traveling of the shutter front curtain.
Cameras having a trigger circuit for triggering a flash device when both the output of the detection means and the signal generated by the signal generation means are detected have been conventionally known. This conventional camera triggers the flash device when both signals are detected because the front curtain needs to be fully open even if the rear curtain is synchronized.

In this system, as shown in FIG. 8, during high-speed synchronization, a signal output after a lapse of a predetermined time from the start of traveling of the shutter front curtain, rather than the synchro signal X which detects the end of traveling of the shutter front curtain. R may be output first. This is a time t1 unilaterally calculated from the timing t1 before the trailing curtain release time t3 by the flash time T of the electronic flash device, that is, from the trailing curtain running start t3.
However, it may occur before the front curtain full opening time t2. If the signal R is to be received by the interrupt function of the microcomputer of the electronic flash device, the following problems occur.

In the line of the signal R, signals having various functions other than the timing of the rear curtain synchronization are multiplexed. Therefore, if the microcomputer of the electronic flash device tries to accurately detect the timing of the rear curtain synchronization, it is certain that the interruption of the signal R after the synchronization signal X is permitted. However, if the signal R becomes active before the synchronizing signal X, even if the edge interrupt expected by the signal R is enabled, the interrupt is not already generated. Therefore, the second-curtain sync flash due to the interruption fails.

[0005]

Due to this problem, a dedicated interface IC has been required in the past, resulting in an increase in cost.

The present invention has been made in view of the above problems, and an object of the present invention is to allow a microcomputer of an electronic flash device to reliably detect the timing of rear curtain synchronization by using an interrupt function.

[0007]

In order to achieve this object, a first invention is a front curtain traveling detecting means for detecting completion of traveling of a shutter front curtain of a focal plane shutter composed of a shutter front curtain and a shutter rear curtain. (1), a signal delay means (2) for delaying the detection output of the front curtain traveling detection means by a predetermined time, and a flash device (10) for performing flash photography, and are associated with the travel of the focal plane shutter. In a camera having a synchronized shooting mode for flash photography, a mode selection means (3) for selecting a first trigger mode or a second trigger mode and a front curtain traveling detection means (1) when the first trigger mode is selected. ) Is detected, the flash device is triggered in synchronization with the shutter front curtain, and when the second trigger mode is selected, the front curtain traveling detection means (1) detects Comprising a power and signal delay means (2) triggering control means for triggering the flash device when detecting both the output and (4).

A second invention is a front curtain traveling detecting means (1) for detecting completion of traveling of a shutter front curtain of a focal plane shutter composed of a shutter front curtain and a shutter rear curtain.
And a flash device (10) for performing flash shooting, and a first delay signal after a predetermined time has elapsed from the start of the shutter front curtain travel in a camera having a synchronized shooting mode for flash shooting in association with focal-plane shutter travel. A first delay signal generating means (5), a second delay signal generating means (6) for generating a second delay signal different from the first delay signal after the shutter front curtain starts traveling, and a first trigger mode. Alternatively, when the detection output of the front curtain traveling detection means (1) is detected when the mode selection means (3) for selecting the second trigger mode and the first trigger mode are selected, the shutter front curtain is synchronized. Trigger control means (7) for triggering the flash device and triggering the flash device when both the first delay signal and the second delay signal are detected when the second trigger mode is selected. That.

[0009]

In the camera having the synchro photographing mode having the above-described structure, by appropriately setting the delay time of the signal delay means, it becomes possible to output the signal indicating the timing of the rear curtain synchronization after the synchro signal is output. The device can reliably detect the timing of the rear curtain synchronization by enabling the interrupt for the timing reception of the rear curtain synchronization immediately after receiving the synchronization signal.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the system including the camera and the electronic flash device, the following description will be made on the assumption that the mode of the rear curtain synchronization has already been set.

FIG. 1 is a block connection diagram showing a first embodiment (corresponding to claim 1) of a camera having a synchronized photographing mode according to the present invention. Further, FIG. 2 shows the running of the front and rear curtains of the focal plane shutter and the state of each signal.
The horizontal axis represents time. FIG. 3 is a flowchart illustrating the operation of the camera and the electronic flash device.

In FIG. 2, at time a, the camera starts a timer TM1 corresponding to the shutter second (FIG. 3).
(A)). When the front curtain is released at time b immediately after that, the synchronizing signal X is generated by the detection means 1 for detecting the traveling of the shutter front curtain at time c after the traveling time of the front curtain (FIG. 3 (b)). ). This synchro signal X enables the interruption of the signal R of the trigger control circuit 4 described later (FIG. 3 (e)). Further, the synchronizing signal X is also transmitted to the signal generating means 2, and the timer TM starts from time c.
2 starts (Fig. 3 (b)). The time of the timer TM2 is obtained by subtracting the flash time Tflash of the electronic flash device 10 (see FIG. 7) from the fully open time Topen of the shutter, and is preset by calculation. Timer T
At the time when M2 overflows, the signal R is output from the signal generation means 2 to the trigger control circuit 4 (FIG. 3).
(F)).

If TM2 is negative as a result of the operation, 0
Alternatively, set a time close to 0. This is because the interrupt of the signal R is generated after the interrupt on the electronic flash device 10 side by the synchro signal X occurs, and a slight time difference is sufficient. In the current microcomputer, about 50 μS is sufficient. In this case, the light emission timing is substantially the same as that of the front curtain synchronization, and the setting may be set to the front curtain synchronization.

When the selecting means 3 sets the second trigger mode, that is, the trailing curtain sync, the sync signal X has already been output, so that the interrupt input of the signal R is permitted and the trigger control circuit 4 The electronic flash device 10 is triggered based on the signal R, and the electronic flash device 10 emits light at time e.

Next, a second embodiment (corresponding to claim 4) will be described with reference to FIGS. 4, 5 and 6. FIG.
6 is a flowchart illustrating operations of the camera and the electronic flash device according to the embodiment.

FIG. 5 shows the running of the front and rear curtains of the focal plane shutter and the state of each signal, with the horizontal axis representing time. At time a, the camera starts the timer TM1 corresponding to the shutter second (see FIG. 6).
(A)). Immediately after that, at time b, the front curtain is released and the timer TM2-1 for predicting the completion of traveling of the front curtain is started (FIG. 6A). Timer TM2- at time c
When 1 overflows, the pseudo sync signal X is output and the timer TM2-2 starts (FIG. 6 (b)). TM2-2 is obtained by subtracting the flash time Tflash of the timer TM2-1 and the electronic flash device 10 (see FIG. 7) from the timer TM1. When the timer TM2-2 becomes negative as a result of the calculation, a value close to 0 is set as in the first embodiment. When the timer TM2-2 overflows (time e in FIG. 5), the signal R is output (see FIG. 6).
(C)), the electronic flash device 10 emits light (FIG. 6).
(F)).

FIG. 7 is a block connection diagram for supplementarily explaining that the connection relationship between the trigger control circuits 4 and 7 and the electronic flash device 10 is unclear in FIGS. 1 and 4. The description of each block is given above.

According to the embodiment described above, the following effects can be obtained.

In the first embodiment, even when the signal input on the electronic flash device side is used as the interrupt input, the order of the signals can be optimized, and the sync signal X interrupts the signal R for the rear curtain sync. Permission is given and correct light emission is performed. Since no dedicated timing IC or the like is required, it is advantageous in terms of cost. Further, since the synchro signal X is also output, even if a conventional electronic flash device is connected, both front curtain synchronization and rear curtain synchronization can be performed, and there is no problem in compatibility.

In the second embodiment, the detecting means 1 for detecting the traveling of the shutter front curtain can be omitted, so that in an inexpensive camera which does not require strict synchronization timing,
It is also possible to pursue lower costs.

[0021]

As described above, according to the camera having the synchro photographing mode of the present invention, by appropriately setting the delay time of the signal delay means, a signal indicating the timing of the rear curtain synchronization can be output after the synchro signal is output. As a result, the electronic flash device can reliably detect the timing of the rear curtain synchronization by allowing the interrupt for the timing reception of the rear curtain synchronization immediately after receiving the synchronization signal.

[Brief description of the drawings]

FIG. 1 is a block connection diagram showing a first embodiment of a camera having a synchronized photographing mode according to the present invention.

FIG. 2 is a timing chart showing a first embodiment of a camera having a synchronized shooting mode according to the present invention.

FIG. 3 is a flowchart showing a first embodiment of a camera having a synchronized shooting mode according to the present invention.

FIG. 4 is a block connection diagram showing a second embodiment of a camera having a synchronized shooting mode according to the present invention.

FIG. 5 is a timing chart showing a second embodiment of a camera having a synchronized shooting mode according to the present invention.

FIG. 6 is a flowchart showing a second embodiment of a camera having a synchronized shooting mode according to the present invention.

FIG. 7 is a block connection diagram showing first and second embodiments of a camera having a synchronized photographing mode according to the present invention.

FIG. 8 is a timing chart showing an example of a camera having a conventional synchronized shooting mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 detection means 2 signal generation means 3 selection means 4 trigger control circuit 7 trigger control circuit 10 electronic flash device

Claims (4)

[Claims] 1. A front curtain traveling detecting means for detecting completion of traveling of the shutter front curtain of a focal plane shutter composed of a shutter front curtain and a shutter rear curtain, and a detection output of the front curtain traveling detecting means delayed by a predetermined time. A first trigger mode or a second trigger mode is selected in a camera having a signal delay unit for performing flash photography and a flash device for performing flash photography, and having a synchronized photography mode for performing flash photography in association with traveling of the focal plane shutter. And a second mode triggering means for triggering the flash device in synchronization with the shutter front curtain when the detection output of the front curtain traveling detection means is detected when the first trigger mode is selected. When the trigger mode is selected, both the detection output of the front curtain traveling detection means and the output of the signal delay means are detected. A camera having a synchronized photographing mode, comprising: trigger control means for triggering a flash device. 2. A camera having a synchronized photographing mode according to claim 1, further comprising shutter speed setting means for setting a shutter speed of said focal plane shutter, and said selecting means is set by said shutter speed setting means. A camera having a synchronized photographing mode, characterized in that one of the first trigger mode and the second trigger mode is selected based on a shutter speed. 3. A camera having a synchronized photographing mode according to claim 2, wherein the selecting means selects the first trigger mode when the shutter speed is higher than a predetermined shutter speed, and the shutter speed is predetermined. A camera having a synchronized photographing mode, wherein the second trigger mode is selected when the shutter speed is slower than the shutter speed. 4. A focal plane shutter comprising a front curtain and a shutter rear curtain, front curtain traveling detection means for detecting completion of traveling of the shutter front curtain, and a flash device for performing flash photography. In a camera having a synchronized photographing mode for performing flash photography in association with shutter travel, a first delay signal generating means for generating a first delay signal after a predetermined time has elapsed from the start of travel of the shutter front curtain, and travel of the shutter front curtain. Second delay signal generating means for generating a second delay signal different from the first delay signal from the start, mode selecting means for selecting a first trigger mode or a second trigger mode, and the first trigger mode is selected When the detection output of the front curtain traveling detection means is detected, the flash device is triggered in synchronization with the shutter front curtain. And a trigger control means for triggering the flash device when both the first delay signal and the second delay signal are detected when the second trigger mode is selected. A camera with a synchronized shooting mode.