JPH0244320A - Camera exposing controller - Google Patents

Abstract

PURPOSE:To control exposure by means of real-time photometry according to brightness distribution and to appropriately expose by control the opening time of a shutter with the aid of weighted photometry element output according to a photographing mode discriminated based on photometry result. CONSTITUTION:A photometry means 16 and 17 holding photometry elements SP and AVE which at least photometrically meters the brightness of objects of the central and peripheral part of a photographing screen are provided. Before releasing the shutter, a means 20 is provided which discriminates according to the metered result that the current operation is in which photographing mode and which weights the photometry element output for the real-time photometry after releasing the shutter according to this discriminated photographing mode. This weighted output controls the opening time of the shutter. Thus, it is discriminated whether photographing is by natural light or by flash, and more proper exposing can be carried out according to all sorts of photographing mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for controlling exposure time during photographing in a still video camera or the like.

[Prior Art] In an exposure control device for a camera, in order to obtain proper exposure, the brightness of a subject is measured and the exposure time is appropriately controlled according to its distribution.

For example, in a device that performs real-time photometry with the shutter open, you can manually change the ratio of the output combination of spot metering, which measures the subject brightness at the center of the shooting screen, and peripheral metering, which measures the brightness at the periphery. However, this device is not designed to automatically set an appropriate ratio according to the luminance distribution of the subject.

In addition, a method has been proposed in which the ratio of the output combination of spot metering and peripheral metering is determined according to the brightness distribution of the subject, the exposure value is calculated, and the exposure is controlled based on this calculated value. There is. However, this device is not designed to perform real-time photometry.

[Problem to be solved by the invention ii] By the way, if we consider the case where real-time light metering is performed depending on the shooting conditions using natural light and flash light, most of the reflected light measured by flash light comes from the main subject. On the other hand, when shooting with natural light, the light from the main and secondary subjects is metered. As described above, since the content of the photometry output differs depending on the shooting mode, it is necessary to weight the outputs of peripheral photometry and spot photometry in order to properly perform real-time light control.

The present invention has been developed to meet the above-mentioned needs by weighting the photometry output for real-time photometry according to various shooting mode conditions, such as when shooting with natural light or using flash light. It is an object of the present invention to provide an exposure control device that allows exposure to be obtained.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an exposure control device for a camera having a means for controlling exposure by opening and closing a shutter to photograph and record an image. a photometer having a photometering element that measures the subject brightness in the center and the periphery; and a means for determining which shooting mode the photometer is in based on the result of photometry before the shirt release.
A means is provided for weighting the output of the photometering element for real-time photometry after shutter release in accordance with the shooting mode determined above, and the shutter opening time is controlled using the weighted output. This is what I did.

Furthermore, when determining the above-mentioned photographing mode, the weighting may be changed by taking into consideration whether or not the lens is in the close-up state.

In the above configuration, the subject brightness at the center and periphery of the shooting screen is measured before the shirt release, and based on the photometry results, it is determined which shooting mode the camera is in, for example, when shooting with natural light. It is determined whether the flash is present during photography, weighting is added to the photometry element output for real-time photometry according to the shooting mode determined above, and the shutter opening time is controlled by this weighted output. be done.

[Effect of the Invention J As described above, according to the present invention, the shooting mode such as natural light shooting or flash shooting is determined based on the photometry result,
Since the shutter opening time is controlled by the output of the photometric element, which is weighted according to the determined shooting mode, it is possible to perform real-time photometry and exposure control according to the abdominal skin distribution, ensuring proper exposure. can be obtained. Further, by taking into consideration the setting state of the lens, etc., more appropriate exposure control becomes possible.

Note that the present invention is not limited to the still video camera shown in the embodiment, and can be applied to various cameras. (Hereinafter, blank spaces) [Embodiment] FIG. 1 shows a block configuration of an embodiment of a still video camera equipped with an audio recording device of the present invention.

In the figure, 1 is a central processing unit (hereinafter referred to as CPU) that controls the entire camera, 2 is a group of various switches that input command information etc. to the CPU (details will be described later), and 3 is a power supply circuit. Main battery 4, booster circuit 5 for obtaining power for CCD (described later), backup battery 6, CPU
Regulator 7 for obtaining power for use and general circuits
Consists of etc.

Reference numeral 8 denotes an autofocus (AF) circuit section, which includes an AP circuit 9 that outputs focus and distance information to the CPU, a lens extension motor 10, a lens stop magnet 11, and a lens position detection encoder 12. 13 is a lens switching/barrier opening/closing circuit; 14 is its motor; for example, when the motor 14 rotates forward, the lens is sequentially switched between standard and close-up; when the motor 14 rotates in reverse, it is located in front of the lens, and has the function of an optical path shielding plate. The barrier is then opened and closed.

Reference numeral 15 denotes a circuit section for automatic exposure <AE), and this circuit section 15 includes a spot photometry circuit 1 which receives as input a detection signal of a photometry element SP that measures the subject brightness at the center spot of the photographing screen.
6. Photometric element A that measures the subject brightness in the peripheral area of the shooting screen
a photometric circuit 17 that receives the VE detection signal as input; an A/'D conversion circuit 18 that converts these detection data from A/D;
A serial communication interface 19 receives this A/D conversion data and performs serial communication with the CPU, and the above-mentioned detection is performed as described below so that appropriate exposure can be obtained based on the commands from the CPU that are input via the interface 19. a weighting circuit 20 that weights data;
It includes a level shift circuit 21 that shifts the level of a signal based on the output of the weighting circuit 20 and a command from the CPU without intervening the interface 19.

Reference numeral 22 denotes a circuit section for controlling the actual closing timing of the CCD shutter based on the output from the AE circuit section 15, which connects a capacitor 25 for timekeeping and a capacitor 25 which is opened at the timing when the shutter is opened. The connection point potential ■ between the switch 26 that releases the short circuit, the capacitor 25, and the output part of the level shift circuit 21 is referenced to the reference potential V.
It consists of comparators 27 and 28 for comparison with O and Vl.

23 is the release signal and C for shooting the CCD shutter.
A control circuit that opens based on a pulse signal from the CD driver 32 and closes when a predetermined exposure is obtained by the output of the comparator 28 of the circuit section 22 or a forced close signal from the CPUI, A shutter opening/closing signal is output to the CPUI and CC/D driver 32.

Reference numeral 24 is a gain control discrimination circuit, which determines whether the predetermined exposure (exposure ff1 less than the appropriate exposure by a predetermined one) was not obtained even after the camera shake limit time was exceeded based on the output of the comparator 27 and the close signal from the shutter control # circuit 23. Tokina t
Then, a signal for electrically controlling the gain of the video recording @ signal is given to the CPU 1.

29 is a recording microphone; 30 is an audio circuit that operates in response to a recording control signal from the CPU; the output of this audio circuit 30 is given to a video recording circuit 34, which will be described later.

31 is a CCD image sensor (hereinafter referred to as COD), which is a solid-state imaging device that converts optical image information into electrical signals;
2 is a driver that drives the CCD 31, and this CCD driver 32 receives the output of the CCD shutter control circuit 23, C
It operates in response to the ISO sensitivity switching signal from the PUI, the synchronization signal PG generated in synchronization with the rotation of the floppy disk, etc.

34 is a video recording circuit for magnetically recording images and audio onto a floppy disk, and 35 is a magnetic head thereof. It operates in response to a digital information signal (year, month, day, track mark, etc.) displayed simultaneously with the image, a gain control output, and a synchronization signal PG.

36 is a spindle motor driver for driving the floppy disk to rotate at a constant speed according to a command from the CPUI, and 37 is a spindle motor.

38 is the magnetic herad 35 according to a command from the CPUI.
A spindle motor driver 39 is a stepping motor for moving the
As a result, the magnetic head 35 is controlled to move to a predetermined track position on the floppy disk. 40 is a head holding plunger for setting the head in a predetermined position during recording (writing).

41 is a flash that fires when the exposure amount is insufficient during shooting, and it has a built-in charging circuit and booster circuit for flashing.
The boost operation is started by the boost signal from the CPUI, and the CP
Based on the charging completion monitor signal from the UI, a charging completion signal is output to the CPU when charging is completed. Also, CPUI
The flash is emitted by a light emission trigger signal from.

42 is a reset circuit for preventing abnormal operation when the power supply is low; 43 is an LED that flashes to indicate when the CCD shutter is opened in a self-timer mode during photographing; and 44 is a floppy disk. If the insertion tube's insert lid is left open, etc.
A buzzer that generates a sound to alert the user, 4
A display section 5 is operated by the output of the CPU 1 and displays various camera information, setting modes, etc. on an LCD or the like.

The components of the switch group 2 include the main switch SO1 and the switch S for performing photometry and distance measurement prior to photographing.
l Release switch S2 for performing photographic operations; recording switch S3.1 for selecting recording or non-recording mode;
Switch S4 for switching between single shooting (S, this or original vehicle mode), continuous shooting (C) for shooting multiple shots, and self-timer (SELF) for shooting using a self-timer. , date information changeover switch S, date 1 to information correction switch S6, switch S7 that detects the opening/closing state of the data/kiss, switch S8 that detects the insertion state of the floppy, and detects the presence or absence of the write-protection claw on the floppy. switch s9, switches sio and sit for detecting the open and closed positions of the barrier, switch S12 for detecting the initial position of the lens, lens changeover switch 313 for putting the lens in a close-up state during close-up photography, and a close-up lens switch. Switch S14 for detecting the position (close-up state) and hanging position (standard state). It consists of a switch S15 and a switch S16 that detects the initial position of the magnetic head.

Here, the CPU 1 is equipped with various functional configurations such as a self-timer means and a sequence control means to be described later, and the setting information of the recording switch S3, mode changeover switch 84, etc. is input by the user before shooting, and is stored in the memory in CPtJl. Based on this memory information, the CPU 1 executes predetermined program operations, and camera operations such as video recording and audio recording are performed.

Particularly, in the present invention, when the self-timer mode is selected and set using the mode selector switch s4, recording is performed during the self-timer count before taking an image, whereas when the self-timer mode is not selected, the recording is performed after the end of taking the image. , the sequence is automatically switched using the CPUI.

Hereinafter, the operation of this camera will be explained according to the flowcharts shown in FIGS. 2 to 7.

FIG. 2 shows the main flowchart. In the same figure, when the power is turned on to the CPUI, the CPU1 is reset and reset (#1), and the reset flag is set to "1"(#2).
Initialization of flags and RAM, and to lenses and magnetism.
5 to the initial position (#3). If this reset flag remains "1", it means that the date has not been corrected as described later, and such a date Information is not recorded on the floppy disk, and a warning is given by blinking a part of the LCD. Next, check to see if there is a battery (#4), and if there is no battery, proceed with the battery removal routine. #5 ) If you have a yt switch, check the status of the main switch SO<(#6
).

If the same switch So is currently ON, check whether the deck lid is open or closed, the presence or absence of flow y and -, the presence or absence of a recording prohibition claw, and whether the deck has just changed from open to closed (#7
~#10) If the deck lid has just been closed, the initial load routine locates the beginning of an unrecorded track on the floppy disk, and the magnetic head 35 moves to that position (S11).

After that, if the determination in S10 becomes NO, the state of the photometry/distance measurement switch S1 is checked (S12), and if it has changed from OFF to ON, the photometry/distance measurement, exposure, and subsequent various steps are performed. Process the S1 sequence (shown in Figures 3 and 4) (#13.#14),
+31 is OFF or has been ON from before, do not proceed to S1 Sequences, but check the status of the lens close-up switch 313 (S15), and check if this is OFF.
If the answer is N, the lens switching routine (S16) is processed.

Next, check the state of the mode changeover switch S4 (S1
7) When this is turned on, the date flag is set to "0",
If it is the date switching correction mode, exit this correction mode (#18) and execute the mode change routine (#19).
). Through this mode change process, as mentioned above, the single, continuous, or selfie shooting mode is memorized.Next, check the status of the recording switch S3 (#201) If this is turned on, the recording mode will also be recorded. The flag is set to r□, and if the date switching correction mode is selected, the correction mode is exited (#21) and the recording switching routine (82, 2) is processed.

It should be noted that the close amplifier switch 313, mode changeover switch S4, recording switch 83, etc. all change to a different state each time they are pressed (turned on), and return to the original state when pressed as many times as there are existing states. .

After that, check the status of the date selector switch S5 (#23
), when this is turned ON, the date flag is set to "1" and the date switching correction mode is entered (#24), and the reset flag is set to "O" to enable recording of date information.
25) After a predetermined period of time has elapsed, start a date timer to exit this switching correction mode (#26).
, 6 to process the date switching routine (#27>)
Check the date flag (#28), and if it is "1" and the date correction switch S6 is turned on, start the date timer anew (#29° #30), and execute the date correction routine (#31). ). When the date correction switch 36 is turned off and the date timer time elapses (
YES at #32), set the date flag as 0 (#3
3) Exit the date switching correction mode. In addition, S1
As will be described later in Siegen, the O of the photometry/distance switch S1
Even if it is N, the date switching correction mode will be exited.

After that, it is checked whether the charging circuit of the flash 41 needs to be boosted (#34), and if it is necessary, it is checked whether charging is completed (#35), and if it is not completed, the boost is started. #36> Return to step #4 above. Also, # above
When the main switch SO is OFF in step 6 and # above
34. If step-up is not necessary in #35 or charging is complete, stop step-up #37>, and the first
Start the timer (#38), and until the predetermined time has elapsed (NO in #39), check whether the deck lid is open or closed (#44) and check whether it is closed or open. The switches SO, St, S3 . S4
．． S5. Check for changes in the condition of S6, deck lid, etc. 1
47), if there is a change, return to #4 above; if there is no change, return to #39.

Also, when the predetermined time set by the first timer has elapsed in #39 above, check the setting mode (#40), and if it is self-shooting or continuous shooting mode, change to the standard single mode (#41). Further check the condition of the lens (#
42), If it is close-up, change to standard #43) and proceed to #44 above.Also, when the predetermined time set by the second timer has elapsed in #45 above, the user is alerted with a buzzer 44. emits (#46),
As is clear from this flowchart, when the deck lid is open, A's input is not accepted and only date corrections are possible.

Also, if the deck lid is open in #7 above, proceed to #48, and if it has just changed from closed to open, start the second timer (#49), and continue until the predetermined time elapses. and #8 above. If there is no floppy or no nail in #9 (i.e. recording is prohibited), stop boosting and press (#9).
51) - Proceed to #23 above without checking the status of switch S1, etc., and when the predetermined time of the second time elapses, issue a warning in the same way as above (#52), and also confirm that the deck lid is closed. When this happens, the warning will stop (#53).

Next, an example of the S1 sequence of #14 will be described with reference to FIG. In this example, recording is prohibited during continuous shooting, and recording is performed after continuous shooting, and moreover, when the self-mode is selected, recording is performed during the self-timer.

In Fig. 3, first stop the voltage boost to prohibit charging during recording/recording, and set the #611 date flag to 'OJ. In other words, turn on the switch S1 to exit the date switching correction mode) (#62) , check whether the self mode is memorized (#63), and if it is not self, turn on the spindle motor 37 that drives the floppy to immediately put it into recording standby (#64), and if it is self, turn on the self timer. During counting, in order to save power, the spindle motor 37 is not turned on at this point.

Next, distance measurement and photometry/AE calculation routine (described later) are performed.
#65. After processing #66), it is checked from the calculation result whether or not boosting is necessary (#67), and if it is not necessary, wait for the release switch S2 to be turned on (#68), and if the switch S2 is turned on, , check whether the self mode is stored in memory (#69m) If it is not the self mode, immediately process the self sequence (#70), which will be described later, and turn the spindle motor 37 ON (#71). , open the barrier (#72)
, operates the lens extension motor 10 to extend the lens to the in-focus position (#73), processes a release routine (#74) to be described later, and further processes the video recording circuit 3.
The image is recorded on the floppy disk using a recording device such as No. 4 (#75). In this recording step, date information of year, month, day and track number are also recorded at the same time. Note that when the camera is not in self-mode, recording is performed after taking an image, so it has not been performed yet at this point.

After that, the magnetic head 35 is sent to the next empty track (
#76), reset the lens #77), check whether the memory information for mode selection is continuous shooting mode (#78),
If not in continuous shooting mode, reset continuous shooting flag 2#
79), To finish recording the image, turn the spindle motor 37 to 0FFL (#80), close the barrier (#81) + return the lens to the standard (#82, #83).

Furthermore, if it is not the self mode (NO in #84), check the memory information according to the setting of the recording switch S3 (#85
), if it is in recording mode, the recording operation begins. Set the recordable timer time T of the audio memory to 9.6 seconds (s) (#86) and start the audio memory (#87). Then, the timer counts down and checks whether T=O (#88), and before reaching that point, checks whether the photometry/distance measurement switch S1 has been turned from OFF to ON (#89). In order to indicate the intention to stop recording midway through, switch S1 is set to be turned on again from 0FFL, so if #8 is YES, that is, to stop recording, the 83 count will be described later. Set to "0"#
90), end the audio memory (#95).

If NO in #89 above, check the state of the main switch SO (#91), and if it turns OFF, reset the audio memory as an indication of your intention to stop the current recording from the beginning #92> and start the audio recording process. The process moves to #4 in the main flowchart of FIG. 2 described above. the above#
If the main switch SO remains ON in step 91, then it is checked whether the recording switch S3 has changed from OFF to ON (#93).

This is because if the user wishes to make additional recordings for one captured image, the user can indicate his/her intention by pressing the recording switch S3. That is, recording switch S3
If you press once, the 83 count will be incremented by 1 (#94>, and the process will return to #88.
As the count is incremented, the process returns from #100 to #86 via #101, as will be described later, and the sound timer is set again, allowing additional recording by the number of 83 counts.

When the timer reaches T=O, end the audio memory #95
), the spindle motor 37 is turned on (#96>, and audio is recorded (#97). Here, the track number and the audio compatible track number are recorded.

Date information such as year, month, and day is not recorded.

Next, the magnetic head 35 is moved to the next empty track (#
98), spindle motor 37 to 0FFL (#99),
Check the 33 count (#100), and if this is OJ, return to the standard single if the mode is self or continuous shooting (#102 #103), and return to #4 of the main flowchart. If the 83 count is not 0 at 100, the 83 count is decremented by 1 (#101) and the process returns to #86.Additional recording is thus performed.

Note that if it is not the recording mode in #85, the process moves to #102 without processing the steps of the recording operation described above.

Also, if continuous shooting mode is set in #78 above,
Continuous shooting is executed by setting the continuous shooting flag 2 to "1"(#104), returning to #65, and cyclically processing the above routine. Here, no recording was made during continuous shooting.

In addition, in #68 above, if the release switch S2 remains OFF or becomes OFF, check the continuous shooting flag 2,
If continuous shooting is not in progress, the open/closed state of the electric saucer, main switch, etc.
Check the status of Tsuchi SO and the status of photometry/distance measurement switch S1 (#106 to #108), and check whether they are closed or O.
If it is N or ON, the process returns to #66, and if it is open, off, or off, the process moves to #4 of the main flowchart.

On the other hand, if the continuous shooting flag 2 is "1" in #105, the continuous shooting operation is canceled and the process moves to #79.

On the other hand, if it is determined in #67 that the voltage needs to be boosted, check whether charging is complete (#109>, and if charging is complete, check #109).
Proceed to step 68, but if charging is not completed, check to see if there is bright backlight (#110). As a result, if it is bright backlight and the release switch S2 is turned on (YES in #111 (#69 above) However, in other cases, check the continuous shooting flag 2 that indicates whether or not continuous shooting is in progress (#112). ), stop continuous shooting and proceed to #79 above.If continuous shooting is not in progress, turn off the spindle motor 37 to save power during charging.
(#113), start boosting the voltage (#114), then check whether charging is complete (#115), and if charging is complete, stop boosting (#116), and check again to see if there is bright backlight. (#117), if YES, set the spindle motor 37 to 0NLt"(#118), above #6
Return to 6. If NO, return to #4 of the main flow.

Also, if charging is not completed in #115 above, the deck lid,
Look at each status of the main switch SO1 and photometry/distance measurement switch S1 (#119 to #121), and see if they are closed, ON, or
If it is ON, check whether there is bright backlight, and if it is bright backlight, check the status of release switch S2 (#123)
, if this is ON, stop boosting the voltage without waiting for charging completion (#124), and turn on the spindle motor 37 (#125).
) and take a photo <(Proceed to #69). Also, #12 above
If the judgment in step 2 is NO, that is, when it is dark or #123
When the release switch S2 is OFF, the above #11
Return to 5. Further, when the deck lid is opened in steps #119 to #121, the main switch SO is OFF, and the photometry/distance measurement switch S1 is OFF, the process exits the S1 sequence and moves to #4 of the main flowchart.

Note that when the self mode is stored in memory and the sequence of the same mode (#70) is processed, recording has already been completed, so the process directly proceeds from #84 to #96.

The S1 sequence shown in Figure 3 above is recorded after continuous shooting (
However, as will be described later, in this embodiment, recording is performed during the self-timer count, but below, an embodiment in which recording is performed in the ear will be described with reference to FIG. 4.

In FIG. 4, in this embodiment, if the continuous shooting mode is #
Proceeding from #78 to #104, after setting continuous shooting flag 2 to rl, recording operation is performed, that is, timer T = 9.6 seconds (
s) #201) and start audio memory #
202), the process returns from #203 to #65 until T=O, and thereafter, this routine is repeated to perform continuous shooting and recording.

When T=O, end the audio memory (#204), set continuous shooting flag 2 to "0"#205), and close the barrier (#205).
206), after returning the lens to standard (#207
．． #208), skip routines such as recording #97
Go to and record the audio.

Also, go from #68 to #105, and here continuous shooting flag 2
If is "1", continuous shooting 7 is determined to be stopped.
Set lug 2 to rO'(#209), spindle motor 3
oFFL 7 (#2io) and close the barrier (#211
), after returning the lens to standard (#212.#
213), the process moves to #88, and recording continues for the remaining time of the timer. Also, if the continuous shooting flag 2 is "1" when proceeding to #112 with the uncharged lock, the above #2
Similar to #09 to #213, processing to stop continuous shooting is performed in #214 to #218, and the process moves to #88.

In addition, in this embodiment, additional recording cannot be performed after recording ends after 9.6 seconds have elapsed during continuous shooting, and continuous shooting ends before 9.6 seconds have elapsed (switch/ychi S2 is turned off or uncharged lock). If you do so, you will be able to record additional audio. Further, according to the S1 sequence shown in FIGS. 3 and 4, the barrier is kept open during continuous shooting in order to reduce the time lag.

Furthermore, the corresponding video track number of the audio during continuous shooting can be made to correspond to the track number of the first (first stage of continuous shooting),
It can also be made to correspond to all track numbers.

Next, repeat the self mode sequence in #70 above in the fifth step.
This will be explained using figures.

Set timer T to 9.6 seconds (s) #301) and start voice memory and self-count #302. #
303), during timer counting, flash the LED to indicate that self-counting or recording is in progress (#305), and during recording, #306. #308
The deck lid is opened or the main switch SO is turned off.
When it is FF, please reset the voice memory by self-cancelling as an indication of your intention to stop recording from the beginning #308).
Return to the main flowchart. When the recording continues until the timer counts up (YES in #304), end the audio memory.
Move to 71.

In addition, to record the audio memory to the floppy disk in self mode, after recording the image (#75 in Figures 3 and 4),
This is done in #97. Also, during self-count, LE
Flash D and self-count! #: Although used to indicate that the sound is in progress, this self-use LED may also be used to indicate that recording is in progress during normal shooting (for example, single mode) recording.

Next, #66 photometry/AE in the above S1 sequence
The calculation sequence will be explained with reference to FIG.

16.17 Photometric elements SP, AVE and photometric circuit
Perform photometry (#401) and convert the photometry analog data to A
The data is A/D converted by the /D conversion circuit 18 and stored in the CPUI (#402 to #404).

Next, it is checked whether the switch S1 is AP locked without being pressed (#405), and if NO, the brightness photometric value BV of the center (front) is determined from the brightness photometric value BV2 of the surrounding (abole).
I is subtracted to find the brightness difference ΔBv (#406), and a predetermined correction value α according to ΔBv is subtracted from the photometric value Bv1 of the spot to find the main subject brightness BvS (#4
07), and set the above-mentioned Abe photometry value Bv2 as the background, that is, sub-subject brightness BvA (#408), and if the AP lock is set in #405, #406. Proceed to #408 without processing #407. Here, the AP lock occurs at #405 in the S1 sequence in Figures 3 and 4.
This is only the case when moving from #8 to #66 and performing photometry/AE calculations.

Next, check whether the lens is in a close-up state (#409mN0, the difference between the sub-subject brightness BvA and the main subject brightness BvS calculated above, that is, the degree of backlight Δ
Find BvS (#4.10) and compare this value with the backlight detection level δ (#411). If ΔBvS is smaller than δ, it is assumed that the degree of backlighting is small (frontlighting), and the weighted main subject brightness Bvs - Close, 1/8 B v S
Use +7/8 B vA (#412>, while #4
11, if ΔBvS is larger than δ, the degree of backlighting is large (backlighting) and a backlight flag is set.
15) -BvS is set to Bvs- (#416).

These weightings are performed by weighting circuit 20 (FIG. 1).

Subsequently, when the above process #412 is performed, Bvs
Check whether - is higher than the camera shake limit brightness BvH (#414), if YES, it is judged that it is brighter than the camera shake limit brightness and enters natural light shooting mode ■, and if No, it is judged that it is dark and flashes in the dark. Enter shooting mode ■. Further, when the process of #416 is performed, it is checked whether the sub-subject brightness BvA minus the backlight detection level δ is equal to or higher than the camera shake limit brightness BvH (#417).
If YES, it is bright backlight, so set the transparent flag and set r1#418), backlight flash photography mode■
On the other hand, if No, the background is backlit or the background is dark, so the dark flash photography mode ■ is entered.

First, natural light photography mode (2) will be explained.

In this mode, the initial setting ISO sensitivity SvO determined by the CCD 31 corresponding to the film is set as the sensitivity value Sv.
419>, the maximum brightness B v M at which proper exposure can be controlled when the subject brightness is extremely bright, the maximum shutter speed TvM, the value Av equivalent to the lens aperture, and the value Sv equivalent to the CCD sensitivity (both are Apex values) ), B
vM-TvM+Av-Sv (#420).

Next, the Bvs- obtained in #412 above and the BVM above
Compare the magnitudes of (#421), and if Bvs is greater than BvM, it is too bright, so use 5vO-1 as the sensitivity value Sv (#422), and if BvS- is greater than BvM, perform the process in #422 above. without the need for boosting (
#423), the process moves to the S1 sequence.

Next, the dark Franche photography mode (2) will be explained.

In this mode, compare the main subject brightness BvS plus IEv and the camera shake limit brightness BvH #424)
, if BvS+1 is not less than BvH, #1 #
As the brightness value BvT, set the main subject brightness BvS plus IEv (#425>. As a result, the main subject will be photographed under natural light by IEv from the appropriate value. On the other hand, BvS+1 If is smaller than BVH, the main subject is dark, so set the camera shake limit brightness f3 v H as the control brightness value BvT (#426
).

Furthermore, in order to calculate the correction value for flash dimming, we calculate the value ΔEvN, which indicates how much the main subject will be under from the appropriate level when photographed using only natural light, and calculate the main subject brightness Bv
Obtained from the difference between S and the above control brightness @B vT (#427)
, check whether ΔEvN is greater than -IEV (#428), and if it is, set ΔEvN to -IEv (#429), then check whether ΔEvN is less than -3Ev (#430), and select YES. If so, the correction value K
#431), if No, that is, ΔEv
When N is between -1 and -3, the correction value K is (1/2)ΔE
Set vN+-(3/2) (#432).

Next, check whether the main subject distance is 5m or more (#4
33), if it is 5m or more, flash dimming correction value ΔE
Set vFL to the above correction value of 0.5 #434),
If it is less than 5 m, the tuning light correction value ΔEVFL is set to the above correction value (#435).

Next item, initial setting RSO sensitivity 5VOt! - rso sensitivity value Sv of CCD31 #436), maximum controllable brightness BvM at maximum brightness, maximum shutter speed TvM, lens aperture value AV, and sensitivity value S above
From v, B v M = T v M + A v -3v (#437), and then it is checked whether the control brightness value DvT is equal to or higher than the maximum controllable brightness BvM determined above (#438). If the comparison result is YES, it means it is bright and the ISO! ! i-degree Sv is set to 5vO-1 #439), and then the maximum controllable brightness B at this time is
Similarly, TvM+Av-3v was used after vM~ (#44
01 Control brightness value BvT can be controlled again I & high brightness BvM
- Check whether it is greater than or equal to (#441>, and this comparison result is Y
If it is ES, check the transparent flag (#442), and if the flag is set, check the main subject brightness BvS and the maximum brightness value B above.
Compare with vM- (#443), and if BvS is larger than BvM-, the brightness of the main subject will be bright even in backlight and there is no need for a flash, so set the transparency flag to rQ (#443).
444), transition to natural light photography mode ■.

Above #438. Comparison result of #441 and #443 is N
o, and when the clear flag in #442 is 0, go to #445 and control the flash emission timing Tv by setting the brightness value BvT, ISO sensitivity value Sv, and lens aperture value A.
From v, set Tv = BvT + 5v - Av.Furthermore, check whether the above flash emission timing Tv is greater than or equal to the maximum shutter speed TvM (#446), and if Tv is smaller than TvM, the same timing Tv is It is checked whether the shutter speed is below the limit shutter speed TvH (#447), and if TV is greater than TvH, the Tv determined in #445 is left unchanged and a flag indicating the need for boosting is set (#448), and the process moves to S1 sequence. Also, the determination in #446 and #447 is YES.
When , Tv is TvM (#449) and Tv, respectively.
Set vH (#450) and proceed to #448.

Next, the backlight flash photography mode (2) will be explained.

In this mode, the sub-subject brightness BvA-1 is used as the control brightness value BvT (#451), so that when the main subject is properly exposed, the background will be overshot by IEv. After the process of #451, the process moves to #427, and the same process is performed thereafter.

In addition, in #409 above, if the lens is in a close-up state, proceed to #452, and the camera shake limit brightness value at close-up is BvCU, and the camera shake limit shutter speed T.
vH and close-up aperture value AvCU and initial setting I
From SO sensitivity SvO, BvCU=TvH+AvCU-3
vO, then compare this camera shake limit brightness value BvCU and the sub-subject brightness BvA (#453), and BvA is BvCI.
If it is larger than J, the sub-object brightness BvAg0.75eM
Nff degree value BvT and t (#454), set the flash emission timing Tv from the above BvT, initial setting ISO sensitivity SvO, and close-up aperture value AvCU as Tv = BvT - f - 8vO - AvCU #455 ), pressure boost is required #456), return to S1 Sequence. Also, if BVA is smaller than BvCU, the camera shake limit shutter speed T during close-up
vHC as flash emission timing Tv (#45
7), proceed to #456 above.

Next, the release sequence in S1 sequence (
#74) will be explained with reference to FIG.

This release is controlled based on the photometry/AE calculation results.

If the lens is not in close-up mode and strobe light is not required (NO in #501 or #502), natural light photography will be used, and the center spot (SP) of the light receiving area and the surrounding area (AV
Using the luminance data of E) (#503), the photometry/AE
Weighting based on Bvs- determined in #412 of the calculation sequence is added (#504), which is calculated using C shown in Figure 1.
Weighting is performed by the circuit 20 based on a command from the PU1. Then, set the timer t1 to the camera shake limit time tH.
and starts light adjustment (exposure) together with the timer start (#505.#506), here is TvH.

tH=2 After the start of dimming, the reference standard potential VO for setting the appropriate exposure in the circuit 28 for controlling the shutter opening time shown in FIG. The potentials V are compared and the exposure is terminated when vO≧■. (#511).

If the timer t1 = 0 before reaching this VO≧■ (YES in #508), compare the reference potential ■1 (>VO) and the control potential V (#509), and if V is higher than Vl ( #509: NO), even after the camera shake limit time has elapsed, the subject remains dark and the exposure is insufficient, so increase the gain by a predetermined amount in the gain control discrimination circuit 24 #5
22) End the exposure (#511).
If Vl is greater than or equal to V in 509 (YES in #509),
Exposure is ended (#511) without changing the gain. After the exposure is completed, the process proceeds to #75 of the S1 sequence.

On the other hand, if strobe light is required (YES in #502)
), using the brightness data of only the center spot (SP) of the light receiving part (#512>, add the ΔEvFL and Sv found above as correction values #5 and 13), and use the Bvs- found in #416 above. Check #514) to see if it is backlit from the above transparent flag (#515), and if it is not backlit (
Clear flag - 〇), process #516 to #522 below, and if backlit (clear flag = 1), #523 to #52
7 is processed and the exposure is completed (#511).

In any of these processes, timer t1=t
Set timer t2=tH+tF.

A' T v Here, -T until flash emission at tA=2
vH is the hand wave timing time, tH"2 is the limit time for shaking, and tF is the flash emission time.

Then, natural exposure is started by timer start, and t1
When the value becomes 0, light control starts by emitting a flash.

Regarding the processing after the start of light adjustment, when there is no backlight, the timer t1 in the case of shooting with only natural light as described above is used.
It is the same except that timer t2 is used instead of , and since it is brighter when backlit than when it is not backlit, it is necessary to process whether to increase the gain when timer t2 = 0. Exposure is immediately terminated (#511).

Also, when the lens is in the close-a-y7' state, processes #528 to #536 are performed and the exposure is completed (#51
1), that is, in this process, as in #503 above, the center spot (SP) and the periphery (Ave) of the light receiving section are
Using the brightness data of , and adding correction of AvCU, add weighting of Bvs - 1 (3/4) BvS + (1/4) BvA #530), Hereinafter, #523 to # at the time of backlight mentioned above The same processing as 527 is performed, and the camera shake limit time during close-up is set to -TvHC.

is tHc=2 In addition, in the above embodiment, weighting was added in the case of close-up and natural light modes, but weighting may also be added in backlighting, or the value may be determined separately. Good too.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a still video camera according to an embodiment of the present invention, FIG. 2 is a main flowchart showing the operation of the camera, FIG. 3 is a flowchart showing an example of the sequence of switch S1, and FIG. 4 is a flowchart showing another example of the sequence of the switch S1, FIG. 5 is a flowchart of the self sequence, and FIG.
A flowchart of the operation sequence, and FIG. 7 is a flowchart of the release sequence. 1...CPU, 16.17...Photometering circuit, 20...
・Weighting is a circuit, 22... circuit section for shying control, 2
5... Timekeeping capacitor, 35... Magnetic head,
41... Flash, Sl... Photometry 1111117
Giant switch, S2... Release switch, 513...
・Close-up switch, SP, AVE...photometering element.

Claims (1)

[Claims] (1) In a camera that has a means for controlling exposure and photographing and recording images by opening and closing a shutter, the camera has a photometering element that measures the brightness of a subject at least in the center and periphery of the shooting screen, and a shutter release. means for determining which photographing mode the mode is in based on the result of photometry performed before the shutter release; and means for weighting the photometric element output for real-time photometry after shutter release in accordance with the determined photographing mode. What is claimed is: 1. An exposure control device for a camera, characterized in that the shutter opening time is controlled using the weighted output.