JP2008113377A - Photographing apparatus and its control method, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographing apparatus which displays a photographable time in a bulb photographing mode used for long-time photographing such as astrophotographing to allow a user to know the photographable time and performs user-desired photographing. <P>SOLUTION: The photographing apparatus that can the bulb photographing mode using a battery as a power supply has a remaining amount acquisition means for acquiring information on a remaining amount of the battery when the bulb photographing mode is configured, a bulb photographable time calculation means for calculating a bulb photographable time based on information on the remaining amount acquired by the remaining amount acquisition means and information on electric power consumption necessary for bulb photographing operations, and a display means for displaying the bulb photographable time calculated by the bulb photographable time calculation means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an imaging apparatus control method, and a computer program suitable for use in, for example, a camera that uses a battery for power supply for imaging.

  Among cameras that use batteries for power supply for shooting, it is known to detect the remaining amount of batteries installed in the camera body and display the number of possible shots according to the detected remaining battery level. (For example, refer to Patent Document 1). According to Patent Document 1, displaying the number of images that can be photographed eliminates the situation where the user becomes unable to photograph due to battery exhaustion, despite the composition that the user wants to photograph.

  On the other hand, various cameras such as single-lens reflex cameras have a long time when shooting an object that moves slightly for a long time, such as astronomical shooting, or when shooting an object that is in the dark and has a small amount of light. There is what can perform exposure so-called bulb photography. A single-plane reflex camera capable of performing such bulb photography generally employs a focal plane shutter. In this focal plane shutter, a front curtain and a rear curtain are arranged in front of an image sensor, and the curtain normally shields the image sensor, and the front curtain and the rear curtain travel at an interval to the image sensor. Light passes through and is exposed, and the exposure time is determined by the difference in the travel intervals.

  Therefore, in the above-described bulb photography, the first curtain travels and exposes the first curtain, and the second shutter travels the rear curtain to complete the exposure. The exposure time as the curtain opening time, that is, the time from the first release to the second release can be arbitrarily determined by the photographer.

JP-A-11-52469

  However, even during the bulb shooting, even after the front curtain travels, the camera holds the exposure state. During this period, power is consumed by the electric holding power of the shutter and the power supply to the image sensor. Here, since the photographer can determine the exposure time as described above, the power consumption of one shooting is different, and displaying the number of shootable images as in Patent Document 1 does not allow shooting due to battery exhaustion. The problem of becoming possible is not solved. That is, even if a new battery is charged or the battery is fully charged, the battery capacity decreases due to power consumption due to long-time exposure, shooting conditions, shooting environment, etc., and there is a problem that shooting ends in the middle. Due to this problem, it is not possible to record shooting data, and long-time shooting is wasted.

  Moreover, since secondary batteries, such as a nickel-cadmium battery and a lithium ion battery, are deteriorated depending on the frequency of use and usage environment, the capacity of the deteriorated battery is reduced even when the battery is fully charged. Accordingly, there are cases where the battery capacity is less than the indicated battery capacity, and in this case as well, there arises a problem that shooting is ended in the middle or shooting data cannot be recorded.

  The present invention has been made in view of the above-described problems, and enables a user to perform good shooting even when a shutter is opened for a long time to perform exposure and image pickup. It is.

    In order to solve the above-described problems, the present invention is an imaging apparatus capable of setting a bulb photographing mode using a battery as a power source, and acquires information on a remaining battery capacity when the bulb photographing mode is set. Remaining capacity acquisition means, information relating to remaining capacity acquired by the remaining capacity acquisition means, bulb exposure possible time calculation means for calculating bulb photography possible time from information relating to power consumption required for bulb photography operation, and bulb photography possible And a display means for displaying the bulb exposure time calculated by the time calculation means.

  According to the present invention, in the bulb shooting mode, the bulb shooting possible time can be displayed, so that the user can grasp the shooting possible time and can perform good shooting intended by the user.

  Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a digital single-lens reflex camera including an imaging apparatus to which the present invention is applied. Reference numeral 100 denotes a camera body, which shows a simplified configuration for performing image processing and the like. An interchangeable photographic lens 9 having an aperture mechanism can be attached to the camera body 100.

  Reference numeral 1 denotes a system control circuit 1 that controls the entire camera body 100, and is a microcomputer having a ROM, a RAM, an A / D converter, a D / A converter, and a clock function. The system control circuit 1 acquires battery information, which will be described later, and processes and controls display control of a shootable time in the bulb shooting mode and the like with an internal program. Reference numeral 2 denotes a power supply control unit which is constituted by a DC-DC converter, which controls the DC-DC converter based on an instruction from the system control circuit 1 and supplies a necessary voltage to each necessary unit.

  A battery 3 is attached to the camera, and supplies power necessary for shooting the camera. A microcomputer is mounted inside the battery, and the microcomputer and the camera body 100 communicate with each other regarding battery information. Here, the battery information includes battery capacity, remaining battery capacity, battery voltage, discharge current, battery temperature, battery deterioration degree information, and the like. Battery information transmitted from the battery 3 to the camera body 100 is recorded in a memory in the camera, which will be described later.

  Reference numerals 4 and 5 denote connectors serving as connecting portions between the battery 3 to be mounted and the camera body 100, and connect the power line and the communication line of the battery 3 to the camera body 100. The communication line is directly connected to the system control circuit 1, and the system control circuit 1 determines whether or not the battery 3 is installed depending on whether or not the communication line is connected. Reference numeral 6 denotes a distance measurement control unit that controls focusing of the photographing lens 9. The distance measurement control unit 6 includes a distance measurement sensor, performs distance measurement selected from a plurality of distance measurement points, and takes a photographic lens in accordance with the aperture value (Av value) calculated by the system control circuit 1. Control to open and close the aperture of 9 is performed. Reference numerals 7 and 8 denote lens connection terminals, and the distance measurement control unit 6 controls opening and closing of the diaphragm of the photographing lens 9 described above via the lens connection terminals 7 and 8.

  An exposure control unit 10 controls the shutter 11. The exposure control unit 10 includes a photometric sensor, and performs control to open and close the front curtain 12 and the rear curtain 13 of the shutter 11 according to the shutter time (Tv value) calculated by the system control circuit 1. When the bulb shooting mode is set and released, a front curtain travel start signal is sent from the exposure control unit 10, and the front curtain 12 travels to start exposure. After that, the trailing curtain 13 is in a standby state until the next release.

  Reference numeral 20 denotes an image sensor such as a CCD that converts an optical image into an electric signal. Reference numeral 21 denotes an A / D converter that converts an analog signal output of the image sensor 20 into a digital signal. A timing generation circuit 22 supplies a clock signal and a control signal to the image sensor 20, A / D converter 21, and D / A converter 24, and is controlled by the memory control circuit 23 and the system control circuit 1. An image processing circuit 25 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 21 or the data from the memory control circuit 23. Reference numeral 26 denotes an image display memory.

  Reference numeral 27 denotes an information display unit composed of a TFT color LCD or the like. Display image data written in the image display memory 26 is displayed on the information display unit 27 via the D / A converter 24. The information display unit 27 is installed on the back of the camera, and displays various information notifications by confirming an image after photographing and communicating with the system control circuit 1. The display of the possible shooting time in bulb shooting described later can be confirmed using the information display unit 27 as a monitor.

  Reference numeral 28 denotes a memory for storing captured still image data and coded encoded shooting information attached to the still image, and has a sufficient storage capacity for storing a predetermined number of still images. . An image file generation unit 29 compresses and decompresses image data to form a file, reads an image stored in the image data memory 28, performs compression processing or decompression processing, and processes the processed data as memory connection terminals 31 and 32. To the external memory 30 through the connector.

  The external memory 30 is a detachable memory of, for example, a card type that is configured by using a PCMCIA card, a flash memory card or the like that conforms to a standard. Reference numeral 41 denotes a photographing information display unit, which displays the operating state of the camera with characters, icons, etc. according to the execution of the program in the system control circuit 1 and is installed at a position near the operation unit where it can be easily seen. The display of the possible shooting time in bulb shooting described later is displayed on the shooting information display unit 41 together with the information display unit 27.

  Reference numeral 42 denotes a nonvolatile memory such as an EEPROM that continues to be stored even when the power supply is cut off, and stores recordings such as photographing conditions. Reference numeral 43 denotes a mode dial for selecting various shooting modes of the camera. Reference numeral 44 denotes a shutter switch SW1 that activates the start of shooting. The shutter switch SW1 is turned on during the operation of the shutter button and instructs the start of the shooting operation. Reference numeral 45 denotes a shutter switch SW2, which is turned on upon completion of the operation of the shutter button, and starts a series of photographing processing operations for writing a signal read from the image sensor 20 to the external memory 30 via the image processing circuit unit 25 described above. Instruct.

  Reference numeral 46 denotes a rotary switch for setting shooting conditions and the like. For example, the Tv value and Av value up / down are set while being displayed on the shooting information display unit 41 by rotating the dial switch 46. Reference numeral 47 denotes a switch installed on the exterior of the camera, which includes a switch for determining various shooting conditions, a switch for editing and viewing a shot image, an input control circuit, and the like.

  Next, the relationship between battery voltage or battery capacity and time will be described using a lithium ion battery generally used as the battery 3 as an example with reference to FIG. The battery discharge conditions in the figure represent the situation when a constant current is discharged under the same conditions.

  In FIG. 2A, the vertical axis represents the battery voltage V and the horizontal axis represents the elapsed time, and the battery voltage V changes as the battery discharges as shown in the figure. The battery voltage V at the initial stage is the maximum fully charged voltage of the battery, and the voltage value gradually decreases each time the battery is discharged.

  In the figure, the point t on the horizontal axis is a forbidden voltage value set by the camera body 100, and since the camera cannot guarantee normal operation below this voltage, a notification is displayed and the operation is stopped. When the battery is further discharged, a voltage drop occurs abruptly. When the end voltage of the battery is reached, the protection circuit is activated and the battery is not discharged.

  In FIG. 2B, the vertical axis represents the battery capacity and the horizontal axis represents the elapsed time, and the battery capacity decreases as the battery discharges as shown. The battery capacity at the initial stage is 100% of the fully charged capacity of the battery, and the battery capacity gradually decreases each time the battery is discharged.

  In the figure, the point t on the horizontal axis is the same point as t shown in FIG. 2A, and the case where the camera has reached the forbidden voltage value is indicated as 0%. Actually, there is a battery capacity capable of discharging to the end voltage after that, but since the normal operation of the camera cannot be guaranteed, it is desirable to display the t point of the forbidden voltage as 0% as the remaining capacity displayed by the camera.

  The battery capacity is generally expressed in [mAh]. Assuming that the nominal capacity of this battery is 2000 mAh, if the energy consumption of 1 C (discharge current 2000 mA) continues, it will be close to the end voltage in 1 hour. If the relationship between the prohibited voltage value at which the camera becomes inoperable and the remaining battery capacity 0% is the same, the remaining battery usable time can be determined for a certain amount of energy consumed (discharge current).

  In FIG. 2C, the vertical axis represents the battery capacity and the horizontal axis represents the elapsed time, as in FIG. In the figure, the t / 2 point on the horizontal axis represents half time of the above-mentioned t point, and the battery capacity changes in half time compared to FIG. 2 (b). In this case, there are two situations. is there. One is a case where the discharge current is doubled, and one is a case where the battery is deteriorated so that only half the capacity can be charged. Assuming that the nominal capacity of this battery is 2000 mAh, when the energy consumption of 2C (discharge current 4000 mA) continues, it will be close to the end voltage in half 0.5 hours.

  Also, in the case of a battery that has deteriorated due to the usage frequency or usage environment of the battery, for example, as shown in FIG. 2 (c), even when fully charged, only 50% of the actual capacity can be stored. If it is 100%, it will be in the vicinity of the end voltage in half 0.5 hours. As described above, if the discharge current consumed by the battery and the degree of deterioration of the battery are known, the time until the battery can no longer be used can be calculated from the remaining capacity of the battery.

  Next, specific operation examples and display of the camera will be described with reference to FIGS. FIG. 3 is an operation flowchart when a battery is attached to the camera. When the battery 3 is inserted into the camera body 100 and power is supplied, the system control circuit 1 is activated and the [battery attachment] flowchart is executed by an internal program. To do.

  First, the system control circuit 1 performs initial communication with the battery 3 to determine whether or not the battery is installed (step S301). If communication with the battery 3 is established, the system control circuit 1 determines that the battery 3 is attached, and proceeds to step S303. If communication is not established, the system control circuit 1 determines that the battery is incapable of communication or other battery, and proceeds to step S302 to perform end processing. The routine proceeds to display a warning message.

  When battery communication is confirmed in step S301, the system control circuit 1 makes a data request to the battery 3 with a predetermined command for information acquisition (step S303). The outline of the contents of the predetermined command includes a remaining battery capacity, a battery voltage, a current, a battery temperature, a battery deterioration level, and the like.

  In response to this data request, the system control circuit 1 acquires battery information (step S304) and records the respective data in the memory inside the camera (step S305). The recorded data can be read out at any time by the system control circuit 1 and used for calculation for time calculation to be described later.

  FIG. 4 is an operation flowchart for displaying the available shooting time in bulb shooting. When bulb shooting is set as the camera shooting mode, the system control circuit 1 executes the [bulb shooting possible time display] flowchart according to the internal program.

  First, the system control circuit 1 waits for setting of the bulb photographing mode (step S401). If the bulb photographing mode is set, the process proceeds to step S402. In step S402, the system control circuit 1 communicates with the battery 3 and requests the remaining battery capacity data. In step S <b> 403, the system control circuit 1 can acquire current remaining capacity data from the battery 3. In this way, the configuration in which the system control circuit 1 acquires information on the remaining battery capacity is referred to as remaining capacity acquisition means.

  Next, the system control circuit 1 extracts desired data from the memory information inside the camera in order to detect the current camera state (step S404). Here, the data taken out by the system control circuit 1 is item data having a large change factor as the current consumption of the camera. For example, it affects the information on the mounted device such as a lens that is attached to the camera and supplies power, the temperature information that affects the impedance inside the battery, the camera setting information such as the backlight lighting time, and the recorded image in the memory. For example, recorded size information of a captured image.

  Since the system control circuit 1 knows the consumption current for each of the above-described information, the consumption current required for the camera to continuously shoot during bulb shooting, that is, the power discharged by the battery 3 is calculated. be able to.

  Next, the system control circuit 1 calculates the bulb shooting possible time from the remaining battery capacity and the current consumption during bulb shooting (step S405). In this way, the configuration in which the system control circuit 1 calculates the bulb photographing time from the information regarding the remaining battery capacity and the information regarding the power consumption necessary for the bulb photographing operation is referred to as bulb photographing time calculating means. As will be described later, a more accurate time can be calculated by adding the information related to the power consumption of the processing after the end of bulb photographing and calculating the bulb photographing possible time. Next, in step S <b> 406, the bulb photographing available time is displayed on the photographing information display unit 41 or the information display unit 27. As described above, the configuration in which the system control circuit 1 displays the bulb photographing time on the photographing information display unit 41 or the like is referred to as a display unit.

  FIG. 5 is a diagram showing a display example of the possible photographing time in the bulb photographing mode. FIG. 5A is a display example of the photographing information display unit 41 installed on the exterior of the camera body 100. When the bulb shooting mode is set, “bulb” is displayed as a mode notification, a battery mark indicating the remaining battery level at that time is displayed, and the possible shooting time in the bulb shooting mode as a calculation result is displayed. In this display example, “6H: 39M: 51S” is displayed, indicating that the shootable time is 6 hours 39 minutes 51 seconds.

The photographing possible time in the bulb photographing mode is calculated by the system control circuit 1 performing the following arithmetic processing.
Here, as the condition of FIG.
The actual capacity of the battery is 2000 mAh,
The battery is 100% fully charged,
Assuming that the current consumption during bulb photography continues at 300 mA,
Assume that 500 mA is consumed for 5 seconds for the processing after camera shooting.

First, the system control circuit 1 subtracts the energy required for the processing after shooting from the actual battery capacity, and calculates the capacity of the battery that can be used for shooting in the bulb shooting mode. Using the numerical value assumed above specifically, the battery capacity that can be used for shooting =
{2000 (mAh)-(500 (mA) × 5 (h) / 3600)}
It becomes. This calculation process obtains 19999.3 (mAh).

Next, the system control circuit 1 divides the capacity of the battery that can be used for photographing by the current consumption consumed by bulb photographing, and calculates the photographing possible time in the bulb photographing mode. Specifically, using the numerical value assumed above and the capacity of the battery that can be used for shooting obtained above,
Bulb photography possible time = 19999.3 (mAh) / 300 (mA).
By this calculation processing, a bulb photographing possible time of 6 hours 39 minutes 51 seconds is obtained.
The current consumption is determined by the camera state detection described in step S404 in FIG.

  FIG. 5B is a display example of the information display unit 27 installed on the back of the camera. When the battery information display is selected in the bulb shooting mode, a percentage value indicating the remaining battery capacity at that time is displayed, and the battery charge capacity, which is the degree of battery deterioration obtained from the battery information, is displayed as a percentage value. The possible shooting time for bulb shooting, which is the result, is displayed.

The possible shooting time in the bulb exposure mode is calculated by the system control circuit 1 performing the following arithmetic processing.
Here, as the condition of FIG.
The actual capacity of the battery is 2000 mAh,
The battery level is 80%
The battery ’s charging capacity has degraded to 50%,
Assuming that the current consumption during bulb photography continues at 300 mA,
Assume that 500 mA is consumed for 5 seconds for the processing after camera shooting.

First, the system control circuit 1 calculates the current remaining battery level using the actual battery capacity, the remaining battery level, and the battery charging capacity (deterioration level of the battery). Specifically, using the values assumed above,
The remaining battery capacity at the current time = 2000 (mAh) × 50% × 80%.
By this calculation process, 800 (mAh) is obtained.

Next, the system control circuit 1 calculates the capacity of the battery that can be used for photographing in the bulb photographing mode by subtracting the energy required for the processing after photographing from the current remaining battery level. Using the numerical value assumed above specifically, the battery capacity that can be used for shooting =
{800 (mAh)-(500 (mA) × 5 (h) / 3600)}
This calculation process obtains 799.3 (mAh).

Next, the system control circuit 1 divides the capacity of the battery that can be used for photographing by the current consumption consumed by bulb photographing, and calculates the photographing possible time in the bulb photographing mode. Specifically, using the numerical value assumed above and the capacity of the battery that can be used for shooting obtained above,
Bulb shooting time = 799.3 (mAh) / 300 (mA) = 2.664 (h)
This calculation process obtains the bulb exposure time, 2 hours 39 minutes 51 seconds.
The current consumption is determined by the camera state detection described in step S404 in FIG.

  As described above, the battery information such as the remaining capacity of the battery and the degree of deterioration of the battery is acquired, and the battery information and the current consumption necessary for continuing the photographing and the current consumption necessary after the photographing are completed It is possible to calculate the possible shooting time for shooting.

  In addition, the current consumption in the bubble shooting mode can be calculated more accurately by taking into account the mounted device information, temperature information, camera setting information, recording size information, and the like that are factors that change the shooting environment.

  In the above-described calculation example of the possible shooting time in the bulb shooting mode, it is assumed that 500 mA is consumed for 5 seconds for the processing after the shooting is finished. This is stored in advance in the memory in consideration of the size that can record the current consumed for the processing after the photographing and the time required for the processing at the maximum. However, the present invention is not limited to this embodiment, and the system control circuit 1 may calculate the current consumed for the processing after the end of photographing and the time required for the processing based on the recording size information and the like. By calculating the current consumed for the processing after the end of shooting and the time required for the processing, it is possible to calculate the shooting possible time in the bubble shooting mode more accurately.

  Each unit constituting the imaging apparatus and each step of the imaging apparatus control method according to the embodiment of the present invention described above can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  In addition, the present invention can be implemented as, for example, a system, apparatus, method, program, or recording medium. Specifically, the present invention may be applied to a system including a plurality of devices.

  The present invention supplies a software program for realizing the functions of the above-described embodiments directly or remotely to a system or apparatus. In addition, this includes a case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention. In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. Furthermore, based on the instructions of the program, the OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  As another method, the program read from the recording medium is first written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Based on the instructions of the program, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

It is a block diagram which shows the structure of the camera of embodiment which concerns on this invention. It is a figure for demonstrating the relationship between battery voltage or battery capacity, and time of embodiment which concerns on this invention. It is a flowchart which shows the operation | movement at the time of battery mounting of embodiment which concerns on this invention. It is a flowchart which shows the operation | movement which displays the imaging | photography possible time in valve | bulb imaging | photography of embodiment which concerns on this invention. It is a figure which shows the example of a display of the camera of embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 System control circuit 3 Battery 4 Camera battery connector 5 Battery camera connector 10 Exposure control part 11 Shutter 12 Shutter front curtain 13 Shutter rear curtain 27 Information display part 41 Shooting information display part

Claims (6)

An imaging device capable of setting a bulb shooting mode using a battery as a power source,
When the bulb shooting mode is set, remaining capacity acquisition means for acquiring information on the remaining capacity of the battery;
Bulb shootable time calculation means for calculating bulb shootable time from information related to the remaining capacity acquired by the remaining capacity acquisition means and information related to power consumption required for bulb shooting operation;
An image pickup apparatus comprising: a display unit that displays the bulb exposure time calculated by the bulb exposure time calculation unit.   The imaging apparatus according to claim 1, wherein the remaining capacity acquisition unit acquires information regarding a remaining capacity of the battery by receiving remaining capacity data transmitted from the battery.   3. The imaging according to claim 1, wherein the remaining capacity acquisition unit acquires information on the remaining capacity of the battery by receiving the remaining capacity data and the deterioration degree data transmitted from the battery. apparatus.   The bulb photographing time calculation unit calculates the bulb photographing time from the information regarding the remaining capacity acquired by the remaining capacity acquisition unit, the information regarding the power consumption during bulb photographing, and the information regarding the power consumption of processing after the bulb photographing is completed. The imaging device according to claim 1, wherein the imaging device is calculated. A method for controlling an imaging apparatus capable of setting a bulb photography mode using a battery as a power source,
A remaining capacity acquisition step of acquiring information about a remaining capacity of the battery when the bulb photographing mode is set;
Bulb shootable time calculating step for calculating bulb shootable time from information related to remaining capacity acquired in the remaining capacity acquisition step and information related to power consumption required for bulb shooting operation;
And a display step for displaying the bulb photographing time calculated by the bulb photographing time calculating step. A computer program for controlling an imaging device capable of setting a bulb shooting mode using a battery as a power source,
A remaining capacity acquisition step of acquiring information relating to a remaining capacity of the battery when the bulb photographing mode is set;
Bulb shootable time calculating step for calculating bulb shootable time from information related to remaining capacity acquired in the remaining capacity acquisition step and information related to power consumption required for bulb shooting operation;
A computer program for causing a computer to execute a display step of displaying the bulb exposure time calculated by the bulb exposure time calculation step.

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