JPH03213835A - Camera system - Google Patents

Abstract

PURPOSE:To increase the number of photographs taken until photograph taking actions are impossible by restricting the action of a camera so as to prolong the life of a battery and checking power consumption in the case of detecting that the battery begins to be consumed. CONSTITUTION:The voltage of the battery 1 incorporated in the camera is detected by a battery voltage detection circuit 4, and a CPU 100 decides that the battery begins to be consumed when the detected voltage lowers to a specified value or under. Then, the acting condition of the camera is changed so as to prolong the life of the battery while keeping photograph taking function which is ordinarily required when the battery begins to be consumed, and the power consumption after that is checked to the utmost. Thus, the life of the battery is prolonged and the number of the photographs taken until the photograph taking actions are impossible is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera system that is capable of maintaining photographing operation as much as possible when battery voltage drops.

[Prior art] Conventionally, when it comes to camera battery consumption, when the battery voltage is detected and the voltage drops below a predetermined level, a warning message indicating battery consumption is displayed; ■ Camera operations such as half-pressing, releasing, and zooming are Prohibitions; (1) Forcefully draining the battery by rapidly increasing the power consumption of the circuit (Japanese Patent Publication No. 128299/1983); etc. are known.

[Problems to be Solved by the Invention] However, such conventional technology is based on the premise that if the battery runs out during photography, the photographer must promptly replace it with a new battery.

Therefore, if you are traveling and do not have new batteries on hand,
Due to unexpected battery consumption, a problem occurs in which you are unable to shoot even though there are still scenes you want to shoot.

The present invention was made in view of these conventional problems, and takes into consideration the situation where new batteries are difficult to obtain, and reduces power consumption by restricting camera operation when the battery starts to run out. An object of the present invention is to provide a camera system that increases the number of images that can be taken.

[Means for Solving the Problems] In order to achieve this object, the camera system of the present invention includes a voltage drop detection means for detecting that the voltage of the battery charged in the camera has decreased below a specified value; and operating condition changing means for changing the operating conditions of the camera in a direction that extends the life of the battery when the detection output of the voltage drop detection means is obtained.

Here, there are, for example, the following three operating condition changing means.

■As the battery voltage decreases, the brightness used to automatically fire the strobe when the subject brightness is low is changed to a lower brightness.

- As the battery voltage decreases, the judgment value for the brightness difference between the center and peripheral parts of the subject, which causes the flash to fire automatically when backlight is detected, is changed to a larger judgment value.

■When various operations such as half-pressing or zooming are not performed within a predetermined period of time, the timer setting time until a reset operation such as retracting the lens barrel or returning it to the wide position, or turning off the LCD, is performed. Change the setting time to a shorter time as the battery voltage decreases.

[Function] According to the camera system of the present invention having such a configuration, when the battery starts to run out, the normally necessary shooting functions are maintained while subsequent power consumption is suppressed as much as possible, thereby extending the battery life. It is possible to increase the number of shots taken before the camera becomes inoperable.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, 100 is a CPU, which performs various camera control operations under program control.

A main switch SW1 for turning on the power is connected to the CPU 100. Further, a half-press switch SW2 is connected in parallel to the output side of the main switch SWI, and the half-press switch SW2 does not work unless the main switch SWI is turned on. Further, a release switch SW, 3 is connected in parallel with the output side of the half-press switch SW2, and the release switch SW3 does not work unless the half-press switch SW2 is turned on. Furthermore, SW4 is an operation switch such as a zoom switch or a light emission detection switch, and the main switch SW4 is an operation switch such as a zoom switch or a light emission detection switch.
If I is included, it becomes operable.

Furthermore, a battery 1 is built into the camera, and the voltage of the battery 1 is detected by a battery voltage detection circuit 4 and provided to the CPU 100. When the voltage drops, it is determined that the battery has started to run out.

Furthermore, for the CPU, there is an exposure control circuit 2 and a strobe circuit 3.
, a distance measurement circuit 5 for autofocus, a photometry circuit 6,
- Lens barrel position detection circuit 9, timer 10, motor drive circuit 11 that drives the monitor 12 used for film advance and lens barrel drive, and ISO detection circuit 1 that detects film sensitivity.
3 or an LCD display circuit 15 and an LCD 16 for displaying an LCD.

Here, the light receiving element 7 connected to the photometry circuit 6 has two photodiodes 7a and 7b, and the photodiode 7
a measures the brightness at the center of the shooting screen, and the photodiode 7
b measures the brightness at the periphery of the photographic screen. By being able to measure the brightness of the center and the periphery separately in this way, it is possible to determine that the subject 8 is in a backlit position when the difference in brightness between the brightness of the center and the brightness of the periphery exceeds a certain value. This allows the strobe to fire automatically.

Here, when the CPU 100 determines that the detected voltage from the battery voltage detection circuit 4 is below a predetermined value and detects that the battery has started to run out, the CPU 100 sets the operating conditions of the camera in the direction of extending the life of the battery 1. A control function is provided to change the . Changes to the operating conditions of the camera that are made when this battery voltage drop is detected include: - lowering the judgment level of the subject brightness for low-brightness auto-flash, and - lowering the brightness of the center and peripheral areas for auto-flash based on backlight detection. Increasing the difference judgment value, (1) shortening the reset time of the timer 10, etc.

Next, as a first embodiment of the present invention, a control process for lowering the subject brightness level for low-brightness automatic light emission when the battery starts to run out will be described.

When the main switch SW1 of the camera is turned on, the process starts from step Sl (hereinafter "step" will be omitted) in FIG. 2A, and proceeds to S2, where the battery voltage is determined. is read and compared with the specified value BC2 in the next step 83. The specified value BC2 is the lowest voltage at which the camera can operate, and therefore the battery voltage V
When IC is lower than the specified value BC2, the process proceeds to S4 and the operation is stopped.

If the battery voltage ■ is higher than the specified value 802 in S3, the next 8
The process proceeds to step 5, where it is compared with the specified value BCI.

Here, the specified values BCI and BC2 have a relationship shown on the horizontal axis in FIG. 3. For example, BCI is set to 5.5 volts, which is the voltage used to determine that the battery has started to run out.

In S5, if the battery voltage Vllc is equal to or higher than the specified value BCI, the brightness Lsll of the subject required for strobe light emission is set to a predetermined value SB.
On the other hand, if the battery voltage Vac has started to be consumed and is lower than the specified value BCI, the process proceeds to S6, and the brightness of the subject required for strobe light emission is set to a predetermined value SB2. Here, the subject brightness L determines whether or not strobe light is emitted.
The predetermined values SB1 and SB2 set in sll are in the relationship shown on the vertical axis of FIG. In this case, SBI is set, and when the battery starts to run out and the battery voltage ■1 is lower than the specified value BC and is higher than the minimum specified value BC2, the SBI is set lower than the SBI.
Set B2.

Depending on the value of the subject brightness LSI+, which determines the presence or absence of strobe light emission according to the battery voltage, when the battery voltage is normal, the strobe automatically fires when it is darker than the predetermined value SB1, but when it is darker than SB2, which is lower. Otherwise, strobe light will not be emitted, which will result in a reduction in the strobe light emission rate and extend the battery life.

The relationship between the strobe light emission rate and the number of shots that can be taken due to battery life is shown in the following table, for example.

In this table, the number of films in the upper row for 20-second recycling and 3-minute recycling is a 36-shot film, and the number of films in the lower row is a 24-shot film.

As is clear from this table, the number of films that can be photographed can be sufficiently increased by lowering the luminescence rate.

When the setting of the predetermined value SBI or SB2 for the subject brightness LSII necessary for strobe light emission in S6 or S7 is completed, the process proceeds to 88, and the ON operation of the half-press switch SW2 is monitored. When half-press switch SW2 is turned on, 8
Proceed to step 9 and read the ISO device (film sensitivity) by reading the DX code provided on the film cartridge or the like. Next, in 810, the lens barrel position is read and the open F value is calculated.

Subsequently, photometry is performed at Sll, distance measurement is performed at 812, and the process then proceeds to 313 in FIG. 2B, where it is determined whether or not to emit a strobe light. In this strobe light emission determination in S13, the value SBI set in S6 or S7
Or, when SB2 is used, the subject brightness measured in 311 is the subject brightness Ls required for strobe light emission at this time.
If the subject brightness is lower than o, the process advances to 814 and performs a flashmatic calculation (FM calculation).On the other hand, if the subject brightness is higher than the subject brightness LsB required for strobe light emission, the process advances to S15 and performs an AE calculation.

Next, the process proceeds to S16 to monitor whether the release switch SW3 is turned on, and if the release switch SW3 is turned on, the process proceeds to S17.
After the photographing process is completed, the process returns to 88 in FIG. 2A.

On the other hand, if it is not determined in S16 that the release switch SW3 is on, the process advances to 818, where it is again determined that the half-press switch SW2 is on, and the process continues.
If it is on, the process returns to step 316, and if the half-press switch SW2 is off at this time, the process returns to 88 in FIG. 2A.

Of course, in the photographing process of S17, the exposure operation and 81
Proceeding to step 4, if flashmatic calculation is being performed in the strobe mode, strobe light emission control and film winding after the photographing operation is completed.

Next, as a second embodiment of the present invention, a control process for widening the brightness difference between the central part and the peripheral part of the photographing screen, where automatic flash is performed for backlight detection when the battery starts to run out, is performed as shown in FIGS. 4A and 4B. This will be explained with reference to a flow diagram.

Since the basic structure of the operation flow shown in FIGS. 4A and 4B is the same as that in FIGS. 2A and 2B, only the differences in the second embodiment will be described.

First, in the second embodiment, as shown in FIG.
As in the example, the horizontal axis represents the battery voltage. is divided into predetermined values BCI and BC2, and when the battery voltage higher than BCI is normal, the strobe light emission judgment brightness difference ΔL, 8 is set as the predetermined value L1, and when the battery starts to wear out, the battery voltages v and c become lower than the predetermined value BCI. If it is equal to or higher than the minimum specified value BC2, a higher predetermined value L2 is set as the strobe light emission determination brightness difference ΔLSB. The set of LL and L2 for the strobe light emission stable luminance difference ΔL5 according to the battery voltage v8C shown in FIG. 5 is S5, 86.86 shown in FIG. 4A. This becomes the process of S7.

Then, the strobe light emission determination brightness difference ΔLSB set to Ll or L2 in S6 or S7 is used to determine the strobe mode at 813 in FIG. 4B, and the brightness difference between the peripheral area and the center area obtained by photometry of Sl If it is larger than the strobe light emission determination brightness difference, it is determined that it is strobe mode and S14
A flashmatic calculation is performed, and automatic strobe light emission based on backlight detection is performed in the photographing process of S17.

Regarding this automatic strobe firing, when the battery starts to run out, the judgment value for automatically firing the strobe based on the brightness difference between the center and periphery of the shooting screen is set to a larger value, thereby reducing the strobe firing rate in response to backlight detection. Extend battery life and battery voltage Vs. It is possible to increase the number of images to be taken until BC2 becomes equal to or less than the minimum specified value BC2.

Next, as a third embodiment of the present invention, control processing for shortening timer reset time will be described with reference to the operational flow diagram of FIG.

In FIG. 6, the processes from Sl to 84 are the same as in the first embodiment shown in FIG. 2A. When proceeding to S5, the battery voltage vll
c is compared with the specified value BCI for determining the start of battery consumption shown on the horizontal axis in FIG.
The set time T until resetting is set to T=71.

On the other hand, the battery voltage begins to drain and the battery voltage ■. If T is lower than BCI, the process advances to S6, and the set time T until the timer 11 is reset is set to a shorter time T=T2.

Next, proceed to S8 to start timer 10, and then proceed to S8.
At step 9, check whether various operation switches such as the mode changeover switch for switching between tele and wide, the zoom switch, etc. are turned on. If it is determined that a switch has been turned on before the timer started in S8 times up, the process proceeds to 810, where processing corresponding to each switch operation is executed, and after the processing is completed, the timer is reset in 811 and the timer is restarted in S8. Let's do it. On the other hand, if it is not determined in S9 that the switch is on, the process proceeds to S12, where time-up is checked, and the processes of S9 and S12 are repeated until the time-up is reached. S9. If no switch operation is performed during the process of S12, time-up is determined after the set time T set in S6 or S7 has elapsed, and the process proceeds to S13, in which the lens barrel is retracted into the camera body or returned to its initial position. The lens barrel is reset and the LCD is turned off, and the series of processing ends in S14.

At this point, the battery begins to run out and the battery voltage ■, c becomes the specified value B.
If the timer setting time until the timer becomes lower than CI and is reset at 86 has been changed to a shorter setting time T2, S9. By shortening the timer setting time to wait for a switch operation in S12 to T2, and resetting the lens barrel and turning off the LCD earlier than the normal setting time T1, wasteful power consumption is avoided, thereby suppressing battery consumption. be able to.

Furthermore, the first. In addition to the second and third embodiments, battery voltage vBc
When the voltage falls below the specified value BCI, film feeding operations such as film feeding may be temporarily interrupted and resumed after the battery voltage has recovered to the specified value BCI or higher.

[Effects of the Invention] As explained above, according to the present invention, when it is detected that the battery has started to run out due to a drop in battery voltage, the camera operation is restricted to extend the battery life and the power consumption is reduced. To keep the number of images to a minimum, to increase the number of images taken before photographing becomes impossible, and to continue photographing as much as possible even in a situation where new batteries are difficult to obtain.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention; Figs. 2A and 2B are operation flow diagrams showing control processing of the first embodiment of the present invention; Fig. 3 is a battery voltage and strobe light emission brightness in the first embodiment. - Figures 4A and 4B are operation flow diagrams showing the control processing of the second embodiment of the present invention. Figure 5 is the characteristic of the battery voltage and the strobe light emission judgment brightness difference for backlight detection in the second embodiment. Figures: Figure 6 is an operation flow diagram of control processing according to the third embodiment of the present invention; Figure 7 is a characteristic diagram of battery voltage and timer setting time according to the third embodiment. In the figure: 1: Battery 4: Battery voltage detection circuit 3: Strobe circuit (S8 circuit) 6: Photometry circuit 7: Photodetector elements 7a, 7b: 10: Timer 100: CPU 5WI: Main switch SW2: Half-press switch SW3 Switch SW4: Operation switch photodiode Figure 5 ■ Figure 4B

Claims (4)

[Claims] (1) Voltage drop detection means for detecting that the voltage of the battery charged in the camera has fallen below a specified value; when the detection output of the voltage drop detection means is obtained, A camera system comprising: operating condition changing means for changing camera operating conditions; (2) The operating condition changing means changes the determination brightness for automatically firing the strobe when the subject brightness is low to a lower determination brightness as the battery voltage decreases. camera system. (3) The operating condition changing means changes the judgment value of the brightness difference between the center and the periphery of the subject, which causes the flash to automatically fire when backlight is detected, to a larger judgment value as the battery voltage decreases. The camera system according to claim 1, characterized in that: (4) The operating condition changing means performs a reset operation such as retracting the lens barrel or returning it to the wide position or turning off the LCD when various operations such as half-pressing or zooming are not performed within a predetermined period of time. 2. The camera system according to claim 1, wherein the set time of the timer is changed to a shorter set time as the battery voltage decreases.