JPH02160224A - Flashing controller for electronic still camera - Google Patents

Abstract

PURPOSE:To achieve appropriate exposure control without incorporating a circuit for stopping flashing in a camera or a flash by making the best use of an electronic shutter function obtained by a CCD and selecting the opening/ closing of a shutter and the timing of flashing. CONSTITUTION:The camera is the one employing a solid-state image pickup element such as a CCD, and has an electronic shutter control means 22. When a normal mode is selected, the timing of flashing is determined based on information on photometry of an object to permit flashing, and when appropriate exposure is achieved, the shutter is closed. When a forcibly flashing mode is selected, flashing is allowed at the timing of opening the shutter, and when appropriate exposure is achieved, the shutter is closed. In such a way, the forcibly flashing mode and the normal mode are arbitrarily to achieve appropriate exposure control although a flashing stop circuit is not provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flash emission control device for an electronic still camera.

[Prior Art] Conventionally, in an electronic camera using a solid-state image sensor such as a CCD, it has been known to control the timing at which a flash starts emitting light in order to obtain appropriate exposure.

For example, in Japanese Patent Application Laid-Open No. 58-104573, CCD
It has been shown that the start of charge accumulation and the flash light emission can be synchronized, and the transfer of the accumulated charge and the flash light emission stop can be synchronized.

Also, JP-A-58-147719, JP-A No. 58-1477
No. 20, No. 58-147722, No. 58-14772
Publication No. 3 states that if proper exposure is not achieved even after a predetermined period of time has elapsed from the start of charge accumulation in the COD, the flash is automatically emitted, and when the proper exposure is reached, the flash is stopped to emit light and the charge accumulation is also stopped. What was made to stop it is shown.

Furthermore, in Japanese Patent Application Laid-Open No. 59-123825, exposure amount control (combined control of exposure time and aperture value) is performed using the photometric output obtained by measuring the peripheral part of the photographic drawing, and the flash is controlled using the photometric output obtained by measuring the central part. It has been proposed to control the amount of light emitted.

[Problems to be Solved by the Invention] Incidentally, the above-mentioned conventional technology requires a flash stop circuit for stopping the light emission of the flash, and the structure tends to become complicated accordingly. In addition to the automatic flash mode in which the flash fires when necessary, the photographer may also want to force the flash to fire to emphasize the flash light, regardless of whether or not the flash is necessary. However, the above-mentioned conventional technology is not capable of supporting each such mode.

Therefore, the present invention makes effective use of the CCD electronic shutter function and appropriately selects the shutter opening/closing and flash emission timing, thereby eliminating the need for a built-in circuit in the camera or flash to stop the flash emission. This was done to simplify the configuration, and also allows the photographer to switch between forced flash mode and automatic flash (normal) mode as needed.
It is an object of the present invention to provide a flash emission control device for an electronic still camera that can selectively perform appropriate exposure control.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides selection means for selecting either a forced flash mode in which the flash is forced to fire or a normal mode in which the flash is not forced to fire, and a method that measures the brightness of a subject. It is equipped with a photometry means, a flash emission control means that determines the timing of flash emission based on the photometry information, and an electronic shutter control means that closes the shutter when appropriate exposure is reached after opening the shutter, and the normal mode is selected. is set, the flash firing timing is determined based on the subject's photometric information, the flash is fired, and the shutter is closed when the appropriate exposure is reached.Also, when the forced flash mode is selected, The flash is emitted at the timing when the shutter is opened, and the shutter is closed when the appropriate exposure is reached.

[Function] According to the above configuration, the forced flash mode and the normal mode of the flash are arbitrarily selected, and in the normal mode, for example, the flash fires just before the shutter jump, and when the appropriate exposure is achieved, the shutter closes. , when the subject is bright, etc., and the proper exposure is reached just before the shutter opens and before the flash fires.
The flash does not fire, and in forced flash mode,
The flash fires when the shutter opens, and the shutter closes when the proper exposure is reached.

[Effects of the Invention] According to the present invention, it is possible to arbitrarily select the forced light emission mode and the normal mode, and to perform appropriate exposure control in both modes, even though a flash stop circuit is not provided. In the forced flash mode, it is possible to take pictures with emphasis on flash light.

Further, in the normal mode, when the subject is bright and proper exposure is achieved with only natural light before the flash is emitted, the shutter is released without emitting the flash, eliminating unnecessary flash emission.

(Hereinafter, blank space) [Example] A configuration diagram of an optical system according to an embodiment of the present invention is shown in Fig. 1. In the figure, 1 is a photographic lens including a zoom lens, and 2 is a photographic lens that passes through the photographic lens 1. A half mirror 13 with a low reflectance that guides a part of the light to the photometric sensor 6 has a half mirror only in the center and a total reflection mirror around the center, and a main mirror 4 that guides the light transmitted through the mirror 2 to the pentaprism 5. 5 is a sub-mirror that totally reflects the light transmitted through the center of the main mirror 3 and guides it to the focus detection sensor 7; 5 is a pentaprism that guides the light reflected by the main mirror 3 to a finder (not shown); 8 is an optical low-pass The filter 9 is a solid-state m-image element (for example, C0D) arranged in a matrix and has a shutter function.

The photometric sensor 6 is a photoelectric conversion element (for example, 5PC)
It has two types of sensors: one that measures light at the center of the shooting screen spot-wise and one that measures light around the periphery of the shooting screen. The sensor 6 is located at a position where the distance it Rb between the reflection point A of the half mirror 2 and the photometric point B of the sensor 6 is equal to the distance RC from the reflection point A to the imaging point C of the solid-state image sensor 9. , and is arranged so as to be equivalent to performing photometry on the imaging surface of the solid-state image sensor 9. Also,
The sensor 6 is placed in a position where the light it receives is not blocked regardless of whether the main mirror 3 is up or down, and can simultaneously measure light even when the solid-state image sensor 9 is exposed when the mirror is up. There is.

The focus detection sensor 7 has, for example, two CCD line sensors that each receive images from different exit pupils of the photographic lens, and uses a phase difference detection method of the two images to determine the amount of focus shift or detect the amount of focus. It detects the amount of focus.

In the above configuration, when the photographer presses the shutter button halfway, a system controller (not shown) calculates the amount of defocus based on the output of the focus detection sensor 7, and
Based on this, the photographing lens 1 is driven and focused. After the object has been focused, the photometric sensor 6 measures the brightness of the object, and based on the brightness information, the system controller determines the charge accumulation time of the solid-state TM image element 9 (i.e., the opening time of the shutter). Calculate the necessity of a flash and the timing of flash emission. When the photographer presses the shutter button all the way down to release the camera, the main mirror 3 flips up, the sub mirror 4 folds up,
Exposure to the solid-state image sensor 9 is started. That is,
The solid-state image sensor 9 starts accumulating charges. Further, the photometric sensor 6 starts photometry at the same time as the charge accumulation in the solid-state image sensor 9, and when it is detected that the amount of photometry has reached the appropriate exposure value, it stops the charge accumulation in the solid-state image sensor 9, and The accumulated charge is transferred to the analog memory section and the photographing is completed.

In addition, in the configuration of this embodiment, while taking the configuration of an eye reflex camera, the solid-state image sensor 9 has a shutter function,
Furthermore, all apertures are removed in order to downsize the camera and simplify the mechanism. Therefore, the main mirror 3 and sub-mirror 4 placed in front of the solid-state image sensor 9 are
It is configured to completely shield the low-pass filter 8 and the solid-state image sensor 9 from light. This prevents the color filter (not shown) from fading (burning) and also prevents the solid-state image sensor 9 from accumulating unnecessary charges at times other than when the camera is released.

Next, FIG. 2 shows the system configuration of this embodiment.

In the figure, 10 is a system controller (CPUI) that controls the sequence of the entire camera section, 23 is a system controller (CPU2) that controls the sequence of the video section, and 11 is a system controller (CPU2) that controls the sequence of the video section. This is a control circuit block consisting of a CCD line sensor for focus detection and an interface circuit section for focusing (AF) on the image.
/D conversion and output 1a function is controlled. Further, 12 is a DC/DC converter that generates different power supply voltages for each circuit block and supplies power; 13
1 is a clutch circuit for switching the power of the motor M to the photographing lens 1, the main mirror 3, and the sub-mirror 4;
4 is a light source such as an auxiliary light source (LED) of the AP to add contrast between light and dark to a dark subject where distance measurement is not possible and to enable distance measurement, and a light source such as an LED that blinks while the self-timer is operating;
A driving IC 116 for driving the motor M is a photocoupler that generates a number of pulses corresponding to the amount of driving of the photographing lens. Further, 17 is a cave 1 light sensor, which is a sensor 17a that measures the brightness at the center of the photographic screen in a spot.
A sensor 17 that measures the brightness around the shooting screen excluding the center
It has b. Further, 18 is a flash circuit, 19 is a display circuit including an LED display circuit 19a in the viewfinder and an LCD display circuit 19b on the top surface of the camera body, and 20 is a color temperature sensor circuit that measures the color temperature of the light source illuminating the subject. , 21 indicate switches including a switch linked to the shutter button and a mode changeover switch.

Here, each switch of the switches 21 is shown. SO is the main switch for prohibiting camera operation when J is open, and Sl is the main switch that starts AE (auto exposure) and AF (auto focusing). S2 is a release start switch.

33, S4 sets, at the camera manufacturing stage, a correction amount in accordance with variations in imaging sensitivity (i.e., sensitivity of output voltage to a constant exposure amount) corresponding to the ISO sensitivity of the film of the solid-state imaging device 9, which differs individually. These switches S3 and S4 handle 2-bit signals (A, B
) are configured, and the corresponding correction values γ(Ev) are stored in the system controller 10.
When the bit signals (A, B) are input to the system controller 10, the system controller 10 outputs a correction value γ corresponding to the signal, and the luminance measured by the photometry sensor 17 is corrected. That is, the photometric sensor 17a performs photometry at the same time as shooting, and the timing of shutter release is controlled based on the photometric data, so the shutter speed is controlled by correcting the photometric data, and the imaging sensitivity is corrected. For example, (
0,0>=O,OEv, (0,1)−+0.3Ev,
(1,0)=-0,3Ev, (1,1)+0.5E
If the imaging sensitivity of the solid-state image sensor 9 is 0.3 Ev higher than the image sensor 9, if a 2-bit signal (0, 1) is input to the system controller 10, the controller 10 will change the value to (0°1). The corresponding correction value γ of +〇, 3Ev is output, and the photometric luminance of the photometric sensor 17 becomes +〇, 3E.
Since the v correction is performed, the shutter speed is increased by +0.3 Ev, the exposure amount is lowered by 0.3 Ev, and variations in imaging sensitivity are corrected. Note that by increasing the number of bits by increasing the number of switches and storing correction values corresponding to each bit signal in memory, the amount of correction can be made finer.

S5 sets the selected date information with the first switch 55-1 for selecting date information of year, month, day, hour, and minute;
It is a date switch consisting of a second switch 55-2 to be corrected, SO is a deck lid detection switch that detects whether the deck lid is opened or closed, and 57-1 is a date switch that detects whether a floppy disk for recording video signals is loaded in the camera. A floppy detection switch 57-2 detects whether write protection is selected by the write protection selection tab of the floppy disk.

S8 is a switch that detects whether or not the accessory slide copier is connected, and S9 is a switch that detects whether or not the accessory negative copier is connected.

S10 is a switch that detects the playback mode, and S11
is a field/frame switch that changes the recording format to field or frame.
312 is a zoom encoder switch group that monitors the focal length of the zoom lens.

S13 is a forced flash switch for forcing the flash to fire regardless of the brightness of the subject; 314
S15 is a flash prohibition switch for forcibly disabling the flash, and S15 is a mode changeover switch for switching between single/self-timer shooting mode.

Next, 22 is a control IC that controls the drive of each actuator such as the DC/DC converter 12 and the clutch 13 according to the control signal of the system controller IO, the shutter speed of the solid-state image sensor 9, and the control circuit of the flash circuit 18. A of photometric data based on light emission timing 17
/D conversion circuit, appropriate exposure detection circuit, etc.

To explain this control IC 22, the voltage control circuit 2
2a controls the startup and boost voltage of the DC/DC converter 12 using a DC/DC control signal, and the clutch control circuit 22b controls the clutch 13 using a clutch control signal.
The self-control circuit 22c controls the light emission of the light source 14 using a self-control signal, and the motor control circuit 22d controls the activation of the motor M using a motor control signal. In addition, the photointerrupter circuit 22e
counts the number of pulses according to the amount of lens rotation output from the photocoupler 16, and the system controller 10
This is what is output to. In addition, the amplifier circuits 22f1 and 22
f2 converts the output currents of the spot photometry sensor 17a and the peripheral photometry sensor 17b into logarithmically compressed voltage signals and outputs the signals, and the output signals are sent to the double integration control circuit 22g via the switch SWI. Input
It will be done. Further, the control circuit 22g switches the switch SW1, takes in the analog signals output from the amplifier circuits 22f1 and 22f2, converts them into digital signals, and sequentially outputs the digital signals to the system controller 10.

22i is a circuit for causing the solid-state image sensor 9 to start exposure in response to a "shutter open" signal, and for determining whether the exposure amount has become appropriate based on a detection signal from the photometric sensor 17a. The configuration of the circuit 22i for detecting this proper exposure is such that the common terminal of the switch SWI is connected to the common terminal of the switch SWI via the adder M1.
connected to the base of transistor Q,
has its emitter grounded and its collector connected to the inverting input terminal of comparator CP. Further, the collector of the transistor Q is connected to the negative electrode of a capacitor C, and the positive electrode of the capacitor C is connected to a power supply terminal Vcc (not shown). Further, the power supply terminal Vcc is connected to the positive pole of the constant voltage source B, and the negative pole of the identified voltage source B is connected to the normal input terminal of the comparator CP.

In addition, a switch SW2 is connected between the positive and negative electrodes of the capacitor C.
is connected, and the opening/closing of the switch SW2 is controlled by the "shutter open" output from the system controller 10.

In the proper exposure detection circuit 22i, when the switch SW2 is switched from "closed" to "open" by the above-mentioned "shutter open" signal, the capacitor C is charged by the collector current of the transistor Q, and the negative terminal of the capacitor C is charged. Potential (V
) falls and becomes lower than the normal input terminal voltage (■0) of the comparator CP, the output of the comparator CP is inverted to detect proper exposure, and this detection result is used as a signal to command the shutter to "close". The signal is output to the system controller 10 and the shutter control circuit 22n as a signal.

Next, the D/A conversion circuit 22h is connected to the system controller 1.
The brightness correction amount output from 0, for example, the above-mentioned ISO
It converts the adjustment amount for sensitivity variation adjustment from a digital signal to an analog signal, and the correction signal is sent to the adder M1.
The signal is input to the photometric sensor 17 and added to the light reception signal of the photometric sensor 17.

The battery check circuit 22j checks the capacity of the battery. Further, the flash trigger circuit 22j outputs a "flash emission" trigger signal to the flash circuit 18 in response to a flash emission signal input from the system controller 10. In addition, the flash control circuit 22
m is the flash circuit 18 by the "boost start" control signal.
It controls the charging of the main capacitor for light emission (hereinafter referred to as flash circuit charging), detects the charging state of the flash circuit 18, and outputs a charging completion signal to the system controller 10.

22n is a shutter control circuit that outputs a shutter opening/closing signal;
Shutter "open" and "close" control signals are output to the system controller 23 and the time control circuit 24 in response to the "open" control signal and the detection signal of the proper exposure detection circuit 22i, or the forced termination signal from the system controller 10.

The time control circuit 24 is the same as the shutter control circuit 2.
The start and end of exposure of the solid-state image sensor 9 is controlled by the shutter "open" and "close" control signals inputted from the shutter 2n. The video processing control circuit 25 adjusts the video signal based on the gain correction amount input from the system controller 10 and the color temperature information input from the system controller 23, and also adjusts the video signal based on the gain correction amount input from the system controller 10 and the color temperature information input from the system controller 23. The recording signal also controls whether the number of recording tracks is one track or two tracks. Here, the details of the gain correction amount will be described later, but it is determined by each mode such as "frontlight", "backlight", "remote light", "flash mode", "forced flash", etc. -1. OEv, -Q
, 5Ev, 10, 5Ev, +1. This is the correction amount of OEv. Further, 26 is a recording magnetic head and disk, 2
A spindle motor 7 rotates the disk 26. Further, the system controller 23 sends map information (information on empty tracks and recording finished tracks), information indicating that the system controller 10 cannot accept switches such as recording, head feeding, etc.

Next, in FIG. 2 showing the system configuration, the operation of opening and closing the shutter will be explained focusing on the shutter control circuit 22n that outputs the shutter "open" and "close" signals, the appropriate exposure detection circuit 22i, and the system controller 10. do.

First, when a shutter "open" signal "H" is output from the system controller 10, it is input to SW2, starts charging the capacitor C of the detection circuit 22i, and is also input to the EXOR circuit 31 of the shutter control circuit 22n. E
Since "L" is input to the input terminal at the other end of the XOR circuit 31, the EXOR circuit 31 outputs "H" to the time controller 24 and system controller 23 to start exposure of the solid-state image sensor 9. , the system controller 10 opens the shutter only when flash is necessary.
At the same time as the signal is not output, a time count of the flash emission time is started, and when the time count of the flash emission time ends, a flash trigger signal is output from the system controller 10 to the flash trigger circuit 221, and the flash emission starts. .

Next, when the detection circuit 22i detects proper exposure, a shutter "close" signal "H" is output from the comparator CP to the system controller 1o and the OR circuit 32. OR circuit 32
receives the above-mentioned "H" output, and outputs "L" to the EXOR circuit 31, which outputs "L" in response to the shutter "open" signal "I(") input to the input terminal at the other end. Then, the system controller 23 and time controller 24 are notified of the end of exposure. Also, the timing at which the shutter "close J signal is outputted from the detection circuit 22i is determined for a predetermined period of time (
If it is later than the camera shake limit time), the system controller 10 outputs a forced termination signal "g" to notify the end of exposure in the same manner as in the above operation.

The system controller 10 determines the timing of outputting the shutter "open" signal, the timing of inputting the shutter "close" signal, the timing of outputting the forced end signal (shake limit time), and modes such as "frontlight" and "backlight". It calculates up/down of the gain (details will be shown later) and outputs it to the video processing control circuit 25.

28 is a communication line between the system controller 10 and the system controller 23;
For example, switch information signals such as Sl, Sl, date, playback, field/frame, slide copier, negative copier, write or write inhibit, floppy detection, spindle motor ON/OFF, and current track number.

etc. control signals are sent.

Next, the photometry mode classification of subject brightness based on photometry information will be explained using Table 1. As shown in the table, the metering mode for subject brightness is divided into "bright" mode, which allows you to shoot using only natural light, and "dark" mode, which requires supplementary light from a flash. For each case of "Dark", there is a case of "Front light" where the brightness of the main subject on the shooting screen and the brightness of the sub-subject in the background is properly balanced, and a case of "Front light" where the brightness of the main subject on the shooting screen is relative to the brightness of the sub-subject in the background. It can be divided into four types: ``backlit'' cases, which are extremely dark. Note that "front lighting" also includes back lighting.

In addition, for each of the four types of metering modes mentioned above, there is an "auto mode" that automatically determines whether or not the flash is necessary based on the metering results and selects the appropriate shooting method, and an "auto mode" that automatically determines whether or not the flash is necessary based on the metering results and selects the appropriate shooting method. There are three types of shooting modes: ``Forced flash mode'', which fires the flash to take pictures, and ``Flash prohibition mode'', which forcibly prohibits the flash from firing even when the flash is required to provide additional illumination. corresponds. In addition, in the same table, "forced flash" and "flash inhibit" are respectively "forced flash mode" and "flash inhibit mode".
"Flash" or "AE (light emission prohibited)" indicates the shooting mode selected by "Auto mode".

By the way, if we classify the shooting methods in the above shooting modes based on whether or not a flash is required, there are two types: natural light mode, which uses only natural light without using the flash, and natural light mode, which uses the flash and uses both natural light and flash light. It is divided into "flash mode" for taking pictures. In the classification of photometry modes in Table 1 (described later), "flash off" and rAE (flash off)" are "natural light mode", and "forced flash" and "flash" are "flash mode".

Next, the photographing method of the photographing mode for each photometry mode of this embodiment will be explained.

(1) Regarding "Natural Light Mode J": In this mode, when shooting in "flash off mode" in the case of "bright backlight", the brightness of the sub-subject is relatively bright compared to the brightness of the main subject. Therefore, when the main subject is photographed with an appropriate exposure amount, the sub-subject in the background will be photographed with brightness. For this reason, the photometered brightness of the main subject is corrected by +0°5Ev, and when the main subject is properly exposed, the exposure is stopped. By shooting in this way, the main subject will be exposed 0.5 times below the proper exposure.
Although the image is photographed at a low Ev, the background is prevented from being photographed extremely brightly, and the photograph as a whole is beautifully photographed.

Next, when shooting in "flash off mode" in the case of "dark backlight", the brightness of the secondary subject is relatively brighter than the brightness of the main subject, but the brightness of the secondary subject in the background is dark, so the main subject Even if the subject is photographed with the correct exposure, the secondary subject in the background will not be photographed excessively brightly.For this reason, the metered brightness of the main subject is not corrected and the main subject is taken with the correct exposure. Being photographed.

In addition, when shooting in "Flash Off Mode" in "Dark Front Light" and "Bright Front Light" in rAE (Flash Off), the balance between the brightness of the main subject and the sub-subject is relatively appropriate. In this case, the brightness of the entire shooting screen is bright and dark, so the average brightness (Bvs') is calculated by taking into account both the brightness of the main subject and the brightness of the sub-subject, and calculating the weighted average of the respective brightnesses. and then shoot so that the average brightness is the appropriate exposure. Note that when the brightness of the entire photographic screen is extremely low to the threshold value of photometry, the above-mentioned average brightness is such that the weight of the brightness of the sub-subject is increased relative to the brightness of the main object. Additionally, if the brightness of the shooting screen is significantly below the photometry limit, the release will be locked and shooting will not be possible.

(2) Regarding "flash mode": In this mode, "forced flash mode" is considered to be the photographer's intention to take a picture using the flash light source regardless of the brightness of the main subject. Regardless of the mode classification, the flash is emitted by the shutter "open" control signal, and the main subject is photographed with proper exposure.

In addition, in the case of "bright backlight" (hereinafter referred to as "backlight flash mode"), the luminance of the metered subject is -1.
, OEv correction is applied to calculate the appropriate exposure time for the sub-subject, and if the APEX value of the exposure time obtained by subtracting the above correction value 1°OEv is Tv, then after the start of shooting, expose with natural light until the above exposure time Tv. After that, the flash is fired and when the main subject becomes suitable, the exposure is stopped and the photograph is taken.

That is, the background is photographed using natural light to be brighter than appropriate by IEv, and then the main subject is properly photographed using flash light. By photographing in this manner, the main subject can be photographed clearly, and the sub-subject can be photographed brightly relative to the main subject, creating an atmosphere of backlight.

In addition, in the case of "dark backlight j" and "dark front light" (hereinafter referred to as "dark flash mode"), the main subject's measured brightness is +1. Apply the OEv correction, calculate the appropriate exposure time for the main subject, and apply the above correction ff11. When the APEX value of the exposure time including OEv is Tv, after starting shooting, expose to natural light until the above exposure time Tv, then fire the flash and stop the exposure when the main subject becomes suitable. do. That is, the main subject is photographed using natural light IEv darker than appropriate, and then the main subject is photographed appropriately using flash light.

By the way, in the above embodiment, the exposure time corresponding to the flash emission timing time is divided into "backlight flash mode" and "dark flash mode" and calculated by the system controller 10, and the exposure time is calculated at the same time as the exposure of the solid-state image sensor 9 starts. However, instead of calculating the flash firing timing from advance photometry information, the solid-state image sensor 9 is used to measure the secondary subject in "backlight flash mode" and the main subject in "dark flash mode". Alternatively, direct light metering may be performed at the same time as the exposure to obtain the flash firing timing. That is,
In the "backlight flash mode", the sub-object brightness is directly measured at the same time as the exposure of the solid-state TI image element 9 starts, and 1. The flash is emitted when OEv increases, and the exposure is ended when the main subject becomes suitable. In addition, in the "dark flash mode", the brightness of the main subject is directly measured at the same time as the exposure of the solid-state image sensor 9 starts, and 1. Fire the flash when OEv is low,
Exposure may be terminated when the main subject becomes suitable.

This concludes the explanation of how to shoot in each shooting mode, and next,
A description will be given of dividing the photographing mode into modes based on the brightness of the subject detected by the photometric sensor 17.

The photometric sensor 17 is composed of two types of photometric sensors: a photometric sensor 17a that spot-meters the brightness at the center of the photographic screen, and a photometric sensor 17b that measures the brightness around the photographic screen. For example, when photographing a person, the main subject, the person, is often placed in the center of the shooting screen, and the background, which is the sub-subject, is often placed around the periphery of the shooting screen. This method measures the brightness and the brightness of the sub-subject separately.

By the way, the brightness at the center of the photographic screen measured by the photometric sensor 17a (hereinafter referred to as center brightness) is Bvl, and the brightness around the photographic screen measured by the photometric sensor 17b (
(hereinafter referred to as peripheral brightness) is Bv2, the brightness of the main subject is Bvs, and the brightness of the sub-subject is BvA.The photometric value Bv2 can be used as the brightness BvA of the sub-subject such as the background, but the photometric value Bvl is the brightness B of the main subject
It is known that when used as vs, an error occurs. For example, if the main subject is small relative to the shooting screen and is backlit, the background light will wrap around the main subject, the photometric value Bv1 will be larger than the main subject brightness Bvs, and the shooting lens may be a zoom lens. In this case, if the ratio of the size of the main subject to the photographic screen is arbitrarily changed by zooming, the error between the photometric value Bv1 and the main subject brightness [3vs will differ depending on the ratio. For this reason,
The ratio of the size of the main subject to the shooting screen, and
It is necessary to correct the photometric value l3v1 according to the luminance difference between the main subject and the sub-subject to obtain the main subject luminance Bvs. That is, if this correction amount is α, the main subject brightness Bvs is expressed as Bvs=Bvl −a −■. Note that the unit of subject brightness is expressed in Ev value.

Table 2 (described later) is α Pine 1 representing the correction amount α. In the same table, β is the photographing magnification that indicates the size of the subject relative to the photographic screen, and ΔBv is the difference between the peripheral brightness Bv2 and the central brightness Bvl, that is, ΔBv=Bv2−Bv1
It shows. As shown in the table, as β becomes smaller, the ratio of the size of the main subject to the shooting screen becomes smaller, and the amount of light that wraps around from surrounding objects to the photometric sensor 17a increases, so the value of the correction amount α becomes larger. It has become.

Furthermore, as ΔBv increases, the brightness of surrounding objects becomes brighter than that of the main object, and the backlight becomes stronger, so the amount of light that wraps around from the surrounding objects to the photometric sensor 17a increases, so the value of the correction amount α becomes larger. There is. However, when β is smaller than 1/100, the ratio of the size of the main subject to the shooting screen is so small that it cannot be considered as the main subject on the shooting screen, so the correction amount α is not included. .

Furthermore, when ΔBv is 2.75 or more, it can be considered that the amount of light that wraps around from the secondary subject to the photometric sensor 17a is small, that is, the main subject is relatively accurately photometered in strong backlight, and Since the main subject is considered to be a religiously large object, the value of the correction amount α is set small in order to take advantage of the shooting conditions.

Here, the above main subject brightness Bvs and sub-subject brightness Bv
The mode classification of "frontlight" and "backlight" by ^ will be explained.

The brightness difference (B
If 'v^-Bvs) is ΔBv', if the sub-subject brightness is larger than a certain value (δ) compared to the main subject brightness, that is, if ΔBv'> δ, the sub-subject will be smaller than the main subject. ΔBv′≦
In the case of δ, it is assumed that the brightness of the main subject and the sub-subject is well-balanced, ie, "front light".

Table 3 (described later) is a δ map giving the above constant value δ. The δ values in the table were obtained through actual photography, and the δ values vary in three levels depending on the brightness of the main subject. This is because as the brightness increases, the amount of light that wraps around from the periphery to the center increases, making it difficult to detect backlight.
Table constants are carried.

Next, the classification of flash emission modes will be explained.

Exposure time is long, and the brightness is at the limit where photographers can experience camera shake (
Let BvH be the camera shake limit brightness (hereinafter referred to as camera shake limit brightness), and when the overall brightness of the shooting screen is lower than the camera shake limit brightness BvH, "flash mode J" is set in which the flash is emitted to take a picture.

By the way, as for the overall brightness of the shooting screen, since the main subject brightness and the sub-subject brightness are different, the weighted average IBVS' of the main subject brightness Bvs and the sub-subject brightness BvA taking into account the respective brightnesses is calculated as the average brightness of the entire shooting screen. It will be used as In the case of "Front light", Bvs' is given by Bvs'=Bvs/4+(3・BvA)/4, when Bvs'≧BvH, it is "Front light flash mode", and when Bvs'<BvH, Since the entire shooting screen is dark, use "dark flash mode".

In addition, in the case of "backlight", the sub-subject brightness is higher than the main subject brightness, so the value obtained by subtracting the above δ from the sub-subject brightness BvA (BvA -
δ) will be used.

In other words, when Bv・A−δ≧Bvll, the background is bright and the main subject is dark due to backlighting, so the “backlight flash mode” is set in which the flash is emitted, and BvA−δ<
At the time of BvH, since Bvs≦BvA−δ<B v II, the entire photographing screen is dark even though it is backlit, so the “dark flash mode” is set.

In addition, if the center brightness Bvl is lower than the limit of the photometry of the photometry sensor 17a, the reliability of the photometry value is low. The weighted average value l3v that increases
s' is used to perform processing in "low brightness processing mode".

That is, Bvs' =Bvs/8+ (7・BvA)
Using Bvs′ calculated by /8, processing is performed as [dark flash mode].

Below, "Natural light mode J, [Dark flash mode]"
, [backlight flash mode J, and "forced flash mode J", the control of the exposure time of the solid-state image sensor 9 and the control of the flash light emission timing time will be explained.

FIG. 3 shows an example of the exposure time of the solid-state image sensor 9 and the timing time of flash emission. In the same figure, t
H (=2 ””) is the limit exposure time (
The camera shake limit shutter speed) is changed depending on the output of the zoom encoder, that is, the focal length of the lens [f].

tH (=2-TvX) is the highest shutter speed that can control the exposure time of the solid-state image sensor 9, and to is the above tH by 2.
It shows the divided time. Furthermore, T v tA (=2) is the delay time from when the solid-state image sensor 9 starts exposure in response to the shutter start signal until when the flash starts emitting light, and in "flash mode",
After being exposed to natural light for a predetermined time tA, a flash is emitted. Furthermore, t[ indicates the time during which the flash is emitting light, and ts indicates the time at which proper exposure is achieved.

(1) “Natural light mode” will be explained.

The "natural light mode" is divided into three types of photographing methods, which will be explained below, depending on the brightness of the main subject.

■When the brightness of the main subject is very bright and the proper exposure is reached within the time of the maximum shutter speed tH.

Exposure is carried out up to the maximum shutter speed time tH, and overexposure is carried out beyond the time ts at which proper exposure is obtained (tH-ts), so that the captured image is reduced in gain by the image processing control circuit 25. Overexposure is corrected.

By the way, since the exposure time of tH/2 corresponds to overexposure of IEv, the system controller 10 corrects the gain separately for the cases of ts≦to((8, to=tH/2) and tH>ts>to. The amount is changed and outputted to the video processing control circuit 25. That is, when ts≦to, the excessive exposure time (tH-ts) is shorter than tH/2, so the constant gain 1.OEv is decreased. , tH>ts>to, the excessive exposure time (tM-ts) becomes longer than M/2, so the constant gain of 0.5Ev is reduced.

0 When proper exposure can be obtained in a shorter time than the camera shake limit shutter speed tH.

This is a case where proper photography is performed using only normal natural light.
The photographed video is recorded without exposure correction by the video processing control circuit 25.

■ Time ts when the brightness of the main subject is dark and reaches the appropriate exposure
exceeds the camera shake limit shutter speed t11.

Camera shake limit shutter speed tH to prevent camera shake
Exposure is forcibly stopped at , and the gain of the image photographed by the image processing control circuit 25 is increased by 0.5 Ev to correct the underexposure.

(2) “Dark flash mode J will be explained.

In the "dark flash mode", after the solid-state image sensor 9 starts exposure, the main subject in the shooting screen is set to 1. O
Until the time when Ev reaches a low value (this time is defined as tA),
exposed by natural light, then a flash is fired,
Exposure is stopped when the main subject becomes suitable.

This "dark flash mode" is divided into three types of shooting methods depending on the brightness of the main subject. In other words, ■When the proper exposure is reached while the flash is firing.

■When the proper exposure is reached within the camera shake limit time tH after the flash fires.

■If the time tS at which proper exposure is reached after the flash fires exceeds the camera shake limit time t11 (note that t^=t11
(Including the case where the flash is emitted at , and proper exposure cannot be obtained after the flash emission time tF ends).

In the case of (1) and (2) above, exposure is stopped when proper exposure is obtained, and the photographed image is recorded without exposure correction by the image processing control circuit 25. In the case of (2), when the camera shake limit time tII has elapsed, exposure is forcibly stopped to prevent camera shake, and the underexposure is compensated for by increasing the gain of 0.5Ev in the video processing control circuit 25. Ru.

(3) “Backlight flash mode” will be explained.

In the "backlight flash mode", the time from when the solid-state S-image element 9 starts exposure until the secondary subject in the background in the shooting screen has a value higher than the appropriate exposure (this time is set as ta)
After that, the flash is emitted, and when the main subject is properly exposed, the exposure is stopped.

In this "backlight flash mode", there are two types of shooting methods depending on the brightness of the subject. In other words, ■When the proper exposure is reached while the flash is firing.

■When the proper exposure is not reached even after the flash emission time tF has elapsed after the flash emission.

In the case of ■ above, stop the exposure when the proper exposure is obtained,
The photographed video is recorded without exposure correction by the video processing control circuit 25. In the case of (2), since the "backlight flash mode" is used to photograph a subject with a bright background, if the main subject is exposed beyond the flash emission time tF until the time ts when the main subject is properly exposed, the natural light after the flash emission will be Since the secondary subject becomes excessively bright due to the exposure, the exposure is forcibly stopped after the flash emission time tF, and the image processing υ control circuit 25 for the captured image is
No exposure correction is made.

Next, in the above-mentioned "backlight flash mode" and when the distance of the main subject exceeds the limit that the flash light can reach, the above-mentioned flash emission delay time tA after the solid-state image sensor 9 starts exposure is set by 1. The lens is exposed to natural light until the time OEv is added (this time is set as t^'=tA/2), then a flash is emitted, and after the flash is emitted, the exposure is stopped. Similar to the above-mentioned backlight flash mode J, if the time ts at which the main subject becomes properly exposed exceeds the flash emission time tF, the exposure is forcibly stopped after the flash emission time tF, and the image processing control circuit 25 Exposure is corrected by increasing the gain by 1.OEv.In other words, in "backlight flash mode" where the distance of the main subject exceeds the limit that the flash light can reach,
Since the flash does not work effectively as auxiliary light for the main subject, the exposure time using natural light is reduced to half the exposure time using natural light in the above-mentioned "backlight flash mode",
Take a picture so that the overall IEv is clear, then fire the flash and forcefully stop the exposure after the flash finishes,
This increases the overall gain by IEv at the stage of the photographed video. Then, in this way, the overall IEv is lowered so that the difference in brightness between the main subject and the sub-subject is smaller than the actual brightness difference, and the IEv is corrected to be higher overall at the video stage. Therefore, the main subject can be photographed clearly, and the balance of brightness between the main subject and the sub-subject can be appropriately adjusted. Here, the flash emission timing time t^ is
This is the time from the start of exposure of the solid-state image sensor 9 until the flash is emitted, and is calculated by the system controller 10 based on the photometered main and sub-object brightness.

(4) “Forced flash mode” will be explained.

In the "forced flash mode", a flash is emitted when the maximum shutter speed tH has elapsed after starting exposure, and the exposure is stopped when the main subject is properly exposed.

In addition, if the time required for the main subject to be properly exposed exceeds the camera shake limit shutter speed tI+, exposure will be forcibly stopped when the camera shake limit shutter speed tH has elapsed to prevent camera shake, and the underexposure will be corrected. The image processing control circuit 25 increases the image gain by 0.5 Ev for correction.

Next, a sequence for controlling the camera section of the system controller 10 in the electronic camera of this embodiment will be described.

First, the main routine will be explained using the flowchart shown in FIG. In the first state when the camera is loaded with batteries, the system controller IO is reset to the initial state (#5) and executes the initial setting subroutine.
Initial settings of the system controller 10 are performed (#1
0). Next, in steps #15 to #30, it is checked whether the camera is in the shooting state. In other words, the battery for the power supply is in (#15), but the "playback mode" is not selected with the playback switch S10 (#20), the deck lid is not open (#25), or the deck lid is not open. At each step, check whether the state has changed from "open" to "closed"(#30). If the battery is not inserted in each of the above steps, the ``battery removal J subroutine is executed (S200); if the r reproduction mode'' is selected, the ``regeneration'' subroutine is executed (S210). When the deck lid is open, the
The subroutine ``prohibit playback'' is executed to prohibit both recording and playback operations (S220). When a floppy disk for recording is inserted and the state of the deck lid changes from ``open'' to ``closed,'' execute the ``initial load'' subroutine, check the information on the floppy disk, and save that information. Load it into the system controller 10 (
S500).

Next, it is checked whether the main switch SO is turned on (S35). If the main switch SO is turned off, shooting will not begin, so proceed to S110, set the photographing lens 1 to the initial position, and display the LCD display circuit. 21a display (S115), if the voltage is being increased to charge the flash circuit 18, the process proceeds to S145, where the voltage increase is stopped and the flash charging LED display (red) in the viewfinder is turned off. Turn it off (#150) and enter the HALT state (S160). In the HALT state, the sequence execution of the system controller 10 is paused, and the settings of the switches 21 are checked for changes at regular intervals (S
170), if there is no change in the settings, continue the )[ALT state, and if there is a change in the settings, return to #15.

If the main switch SO is turned on, the same switch S
Check whether O has changed from OFF to ON (#40
'). When the main switch SO is turned ON for the first time, set the "boost required J flag" to charge the flash circuit 18 (S45). If it is not the first time the main switch SO is turned ON, skip S45 and turn on the LCD display circuit. 21a is displayed (S50).The LCD display circuit 21a displays field/frame and single/self-timer mode selection, a counter for the number of shots, a battery warning, a recording mode, etc.

Next, check whether the AE and AF start switch S1 is turned on (S55). If the switch S1 is turned on, it indicates that the switch S1 is kept pressed.
Confirm the presence or absence of the "Keep pressing" flag (S60). This means that when switch S1 is pressed anew, AE and AP are performed again, and when switch S1 is held down, new A is performed.
E. This is because AF is not performed. If this flag is not set, execute the rsIJ subroutine and
Perform E (auto exposure) and AF (auto focus) (S80
0), switch S1 is OFF', or
If the "keep pressing" flag is set, next check whether there is a change in each mode of single/self-timer, field/frame, and date information switching (S65).
That is, single/self-timer mode changeover switch S15, field/frame mode changeover switch S15,
11. If none of the switches in date information mode switching 55-1 are kept pressed, switch S15
, S11.55-1 are sequentially checked to confirm whether or not there is a mode change. Execute the subroutine. Date selection switch 55-2 in S75
If is ON, the "date change" subroutine of S240 is executed. If the field/frame mode changeover switch 311 is ON in S80, “
Execute the “field/frame change” subroutine,
If there is no change in each mode, check whether the date has been corrected (S85). If any switch is held down, there is no mode change, so there is no need to check each mode changeover switch. (S70 to S80 are skipped) and the process proceeds to date correction (S85). If the date correction switch 55-2 is pressed, the "date correction" subroutine of S260 is executed. If the date information is not corrected, next check whether flashing is necessary (S90~
#105). This is to set a flag in order to identify whether or not boosting the voltage for charging the flash circuit 18 is necessary depending on whether flash is necessary. If the "forced flash" switch S13 is pressed in S90, the flag "boosting required" should be set #95>, and if the "flash prohibition" switch S14 is pressed in #100, "boosting not required"
Set a flag (#105).

Next, check whether the "boost required" flag is set, and if it is set, start boosting if charging is not completed.
LED display 19b in the viewfinder during flash charging (
red) (#120 to #135). Then, the pressure increase time is confirmed (#140), and when the pressure increase is completed within a predetermined time, the process returns to #15. Here, if the boosting is not completed within the predetermined time, a battery check is performed (#270), and if the "boosting required" flag is not set in #120, or charging has already been completed in #125. If completed, the process proceeds to steps #145 to #170 described above and enters the HALT state. Note that when each subroutine ends, the process returns to step #15(A).

Next, the "initial load" subroutine of #500 will be explained using FIG.

First, execute the battery check subroutine and check the battery capacity (#505). Next, check if a floppy disk is inserted (#510). If it is not inserted, the message "Release cannot be released" in #700 will be displayed. The subroutine is executed to prohibit driving of anything other than the mirror 3 and photographing lens 1. When inserted, the DC/DC is used to supply power to the spindle motor 27 and the video processing control circuit 25.
Converter 12 is activated (#515).

Next, the spindle motor 27 and the video processing control circuit 25 are driven (#520) to read the contents written on the floppy disk 26, that is, 50 tracks of data, and create a map. In addition, the LCD display circuit 1
9b displays the track that is counting up, indicating that the contents of the floppy disk 26 are being checked (#525).

Next, check whether playback mode j is selected using the playback switch S10 (#530), and if "playback mode" is selected, steps #535 to #545 are executed to enter the "playback mode". In other words, check whether there is a recording prohibition claw on the floppy disk 26 (#535), and if there is no claw, recording will be prohibited, so set the "erasure prohibited" flag #540), and if there is a claw, recording will be allowed. Therefore, “erasable”
Set the flag (#545>, and proceed to the "playback mode" subroutine in #210. If "playback mode" is not selected in #530, the floppy disk 26
Check whether there is a recording prohibition claw on the LCD display circuit 19b (#550), and if there is no claw, display the "recording prohibition" on the LCD display circuit 19b of the inserted floppy disk 26 (#555).
Stop the recording operation (#570). Also, if there is a claw, check whether there is an empty track on the floppy disk 26 (#560), and if there is no empty track, display the fact that there is no empty track on the LCD display circuit 19b (#56).
5) Stop the recording operation in the same way as without claws (#
570) If there is an empty track, the process proceeds to #600, moves the head to an unrecorded track based on the map information obtained in #525, and then returns to #15 of the main routine.

Next, “Sl” of #800 executes AE and AF etc.
The subroutine will be explained using FIG. “S.
1'' subroutine sequence executes AP, executes AE after focusing on the subject, prepares the flash to emit light if necessary, and enters release. #805 to #835 before entering AP
Check the battery, power supply, system controller I/roller 2.
3. Perform 8F (fa) for white balance, etc. In other words, if the flash circuit 18 is boosting the voltage, stop the boost (#805), perform a battery check (#810), and set the white balance. To set the balance (WB) to a specific color temperature for daylight #815) and to supply power to the solid-state image sensor 9, video processing control circuit 25, spindle motor 27 and other circuits, use the DC/D
Start the C converter (#820) and reset the system controller 23 (CPU2) (#825)
, activates the color temperature sensor circuit 20 (#830'').

Next, execute the AF subroutine #1200 (described later), perform a focusing operation on the subject (#835), and if the reliability of the focus detection result is low due to low contrast and the focus is incomplete, , displays out-of-focus in the viewfinder,
Return to main routine #15 (#840 to #850)
. When focusing is completed in #840, check whether the self-timer mode is selected (#855); if the self-timer mode is not selected, start the spindle motor 27 to drive the floppy disk 26. and prepares for recording (#860). If the self-timer mode is selected, there is no need to drive the spindle motor during the time until release, so #860 is skipped and the color temperature information of the light source is determined from the color measurement information of the subject by the color temperature sensor circuit 20. (#865) and detects whether the light source is a fluorescent light or tungsten light (#87
0). When the light source is a fluorescent lamp or tungsten light, "Flash required" is displayed to fire the flash and take a picture.
Set the flag (#875).

This is because fluorescent lamps or tungsten light have a different color temperature distribution than sunlight, and it is better to take a picture with a flash light closer to that of sunlight, so that the sound hole can be photographed better, so the flash is automatically fired. When the light source is not a fluorescent lamp or tungsten light, the "Flash Required" flag is not set, and the "Photometry J" subroutine of #1500, which will be described later, is executed to photometer the brightness of the subject (#880).

Next, when the metering of the subject brightness is completed in #880, #88
In steps 5 to #905, various flags are checked to confirm whether or not a flash is necessary. First, check whether the "Flash Required" flag is set (#885), and whether the flag is set or not.
Or, if the flag is not set, but "forced flash mode J, /ll" is selected (#890), then check whether "flash prohibition mode" is selected (#8
95).

If "Flash prohibition mode" is not selected, it is the flash mode, so check that "Forced flash mode" in #890 is selected (#905). If it is selected, "Flash flash mode J" flag is selected. Set it (#910
> Check the charging state of the flash circuit 18 (#
915), the "forced flash mode" flag is set in #910 to identify the fact that the flash light emission timing is different between forced flash 3 o'clock and auto mode.

Next, if charging of the flash circuit 18 is completed in #915, stop boosting the voltage for charging (#920), #8
If the spindle motor 27 has not been started at step 60, the spindle motor 27 is started, preparations are made for recording onto the floppy disk 26 (#925), and the LED display 19a (green) indicates that the flash has been charged in the viewfinder. (#93
0), proceed to #970 and check the release switch S2. If charging of the flash circuit 18 is not completed in #915, start boosting the voltage for charging (#935),
If the spindle motor 27 has been started in #860, its drive is stopped (#940), and the LED display 19a (red) indicating that the flash is being charged is displayed in the viewfinder (#945).
), The reason why the drive of the spindle motor 27 is stopped at #940 is to avoid unnecessary current consumption since there is no need to drive the spindle motor 27 during preparation for flash emission.

Next, check the state of switch S1 (#950),
OFF! , if so, return to #15 of the main routine,
If it is ON, check switch S2 #955
), if switch S2 is ON, the process returns to #15 of the main routine, and the LE in the viewfinder that is charging the flash
Turn off the D display 19a (red) (#965) and proceed to #920 to #930 described above.

By the way, if "forced flash mode" is not selected in #890, the flash will not fire, so
Proceed to #970 and check the release switch S2.
Also, the flash does not fire even when "flash prohibition mode" is selected in #895, so you can use "forced flash" or "o!"・Prohibits the flash from firing, giving priority to the mode.
Change the daylight color temperature set in #815 to #8
Based on the colorimetric information input in step 65, the temperature sensor circuit 2° changes the signal into a signal for adjusting the color balance of the photographed image and outputs it (#900), and then the process proceeds to #970.

Next, check the release switch S2 (#970), and if the switch S2 is OFF, switch 5O1S
1 is confirmed (#1030 to #1035), and if any of them is OFF, the process returns to #15 of the main routine. If both switches 5O1S1 are ON, check whether the deck lid is open or closed (#1040). If the deck lid is closed, return to #865; if it is open, check #22).
Executes subroutine 0 and prohibits all recording and playback operations.

If release switch S2 is turned on in #970,
Make sure the self-timer mode is selected #9
75) If the self-timer mode is selected, the timing time for self-timer photography is counted, the light emitting element 14 is blinked (#980), and the spindle motor 27 is activated.
Start up and prepare for recording on the floppy disk 26 (#985), and after 100m5 has passed, flip up the main mirror 3 and release the light shielding to the solid-state image sensor 9 (#99
0). If self-timer mode is not selected,
Skip #980 to #985 above and main mirror 3
, and activates the solid-state tI1gA element 9 and the video processing control circuit 25 (#995). The power supply start-up time for the video processing control circuit 25 (approximately 100m5)
After counting (#1000), #2000 (described later)
Executes the "Release J" subroutine and exposes the solid-state image sensor 9 (#1005).Next, the solid-state image sensor 9
After the exposure is completed, record the photographed image on the floppy disk 26 (#1010), stop driving the color temperature sensor circuit 20, video processing control circuit 25, and solid-state image sensor 9 (#1015), and close the main mirror 3. Lower it (#102
0>, execute the "head feed" subroutine (designate the next track based on map information) #1025)
, return to #15 of the main routine.

As explained above, in this embodiment, in order to accurately measure the brightness of the main subject and the brightness of the sub-subject in the "Sl" subroutine sequence, AP is executed first and the subject is accurately focused. Photometric (AE) calculations are executed later.

By doing this, in the "photometry" subroutine sequence described later based on accurate photometry data,
It is possible to classify appropriate photometry modes and calculate accurate flash firing timing. Also, in self-timer mode, to avoid unnecessary current consumption,
The spindle motor 27 is not activated until a predetermined period of time has elapsed. In addition, when using fluorescent light or tungsten light as the light source, the color temperature setting is fixed to sunlight (flash light source), so the flash is automatically emitted to take a picture, and the flash prohibition switch S14 is set. [When flash prohibition mode J is selected, the color temperature is automatically adjusted to the color temperature of fluorescent light or tungsten light (AWB)
I try to do that.

Next, the rAFJ subroutine of #1200 (#835 above) for executing AF will be explained using FIG.

First, turn on the power to the focus detection sensor 7 (CCD line sensor #1205), then discharge unnecessary charges accumulated in the focus detection sensor and set it to the initial state (#1
210>, start charge accumulation of the focus detection sensor (#1
215>. Thereafter, the system waits until the interlaced signal lNTl that indicates the end time of charge accumulation of the focus detection sensor is input (#1220), and the interwoven signal lNTl
When detected (#1225), the accumulated charges of the focus detection sensor 7 are transferred to the analog shift register, and the accumulated charges are output from the shift register one pixel at a time, A/D converted, and sequentially input to the system controller 10 ( #123
0).

Next, the system controller 10 detects the defocus measurement from the data imported #1235), determines the reliability of the defocus measurement #1240),
If it is unreliable due to low contrast,
Execute the "low contrast" processing subroutine #
1325), an out-of-focus display is performed (#1330), and the process returns to the main routine (#1320). If there is no lack of confidence due to low contrast, check whether the subject is accurately focused (#1245), and if it is, the information on the previous stop position of the photographic lens 1 and the current movement amount. Information on the current stop position is obtained from the information, and based on this information, the shooting distance is determined using a conversion coefficient according to the focal length Mf at that time, and the shooting magnification β is calculated from this shooting distance and the focal length f. (#1305). Then, the focus LED 19a (green) in the viewfinder is displayed (#
1310), turn off the clutch circuit 13, and switch the connection to the motor M from the photographing lens 1 to the main mirror 3 (#1
315), return to the main routine (#1320
>. Furthermore, if the image is not in focus in #1245, it will be focused in the following steps.

First, the lens extension type conversion coefficient K is read from the ROM in the system controller 10 based on the current focal length f from the zoom encoder switch 312 (#1250
), the defocus scale is multiplied by the conversion coefficient K to obtain the number of pulses N (=Kx
Find D) (#1255). Next, the calculated number of pulses N
into counter J (#1260) in the system controller that monitors the motor rotation amount, and clutch circuit 1.
3 is turned on, the connection to the motor is switched from the main mirror 3 to the photographing lens 1 (#1265), and the driving of the photographing lens 1 is started (#1270).

Next, select "Enable interrupts by counter#"
1275), wait until the counter value = 0 and a counter interrupt occurs #1280), and with the counter interrupt occurring (#1285), stop driving the photographing lens 1 and focus (#1290) >, and in order to check the in-focus state, charge accumulation in the focus detection sensor 7 is started again (#1295), and the interwoven signal lNTl is
Wait until input (#1300), and then enter #1.
Return to #225 and perform focus confirmation processing.0 If focus is incomplete during focus confirmation processing, go back to #1245 to #125.
0 and repeats the routine from #1250 to #1300 until focus is achieved.

Next, the "photometering" subroutine of #1500 (#880 above) will be explained using FIG. 8(a). In addition,
In the figure, the unit used for calculation is the APEX value.

First, calculate the correction of the ISO sensitivity, that is, calculate the corrected ISO sensitivity 5v (-3vo + γ) from the standard ISO sensitivity Svo of the solid-state image sensor 9 and the imaging sensitivity variation correction amount γ (#1503), and then the photometric sensor 17a , 17b start measuring the brightness Bvt (spot photometry value) at the center of the shooting screen and the brightness Bv2 (average photometry value) around the shooting screen (#1505), and then the photometry sensor 17a
The double integration circuit 22g starts converting the luminance analog signal photometered by 17b into a digital signal #1
510), then check whether the A/D conversion of the photometered luminance has been completed #1515), and if it is not completed, wait until it is completed, and when it is completed, it is converted to a digital signal to the system controller 10. Input photometric data (#1520).

Next, check whether the AP-AE lock is completed (#
1525), if the AP-AE is not locked, #
Steps 1530 to #1545 are executed to obtain the brightness difference ΔBv between the peripheral brightness Bv2 and the center brightness Bv1 and the main subject brightness Bvs. In other words, check if Bvl is over 11 #1
530), if it exceeds 11, the center brightness is too high, so fix Bv1 = 11 #1535), if it is less than 11, use the same Bvl and calculate the brightness difference ΔBv between the peripheral brightness Bv2 and the center brightness Bvl =Bv2-Bvl (#1540), then subtract the correction amount α shown in Table 1 from the center brightness Bv1 to obtain the main subject brightness Bvs (=Bv
l−α) is calculated (#1545). When AP-AE is locked, the brightness difference ΔBv and the main subject brightness Bvs have already been determined, so #1530 to #15
Skip step 45 and proceed to #1550 described below.
After switch S1 is closed in the main routine (#55), P-AE enters the photometry (AE) calculation subroutine for the first time (#8 of subroutine "Sl").
80), the process proceeds from #1525 to #1530 without being locked, and the subroutine "Sl
'' from #1040 to #865 and is locked for the first time when the process returns from #880 to #1525.

Next, check if the peripheral brightness Bv2 is over 10.#
1550), if Bv2 exceeds 10, the peripheral brightness is too high, so fix Bv2 = 10 #1555),
If it is 10 or less, Bv2 is used as it is and set as the sub-subject brightness BvA (#1560). Next, the central brightness Bv1
Check whether the brightness is low to the photometric limit value of the photometric sensor 17a (#1565), and if the brightness is low to the photometric limit value, the average brightness of the entire shooting screen for low brightness processing BvS'
Calculate using the following formula (#1595), and proceed to #1600. That is, Bvs 7 · BvA Bvs ' = + If the brightness is not low, calculate the reference value δ for backlight judgment from Table 2 and Bvs (#1570), and then calculate the subject brightness BvA.
The brightness difference ΔBv′ (=BvA−
Bvs) and the determination reference value δ obtained in #1570 (#1575). Here, if ΔBv'> δ, determine that it is backlit and set the "backlit" flag #1580
), set the average brightness Bvs' for backlight processing to Bvs (#1590), proceed to #1600, and set ΔBv'≦δ
If so, it is determined as "frontlight", and the average brightness Bvs' for frontlight processing is calculated using the following formula (#1585), #1
Proceed to 600.

Bvs 3 ・BvABvs'
= +Next, #1600 to #161
Separate the shooting modes in step 5. First, check whether the "Backlight J" flag is set (#1600), and if the flag is not set (if it is "Frontlight mode"), select #1600).
Compare the average brightness Bvs' of the entire shooting screen obtained in 1585 or #1595 with the camera shake limit brightness Bvll, and separate the modes into "flash mode" and "natural light mode"(#1605), if Bvs'≧Bvfl , Next, it is determined whether the flash necessity flag is set (#1606). If the flag is set here, it indicates that the illumination light source is not sunlight but artificial light such as fluorescent light or tungsten light, and that it was set in #875 in Figure 6, indicating that the "Flash mode"
On the other hand, if the flag is not set, the process proceeds to #1620 of the "natural light mode" routine (2). If Bvs'<Bvtl, proceed to #1675 of the "dark flash mode" routine ■.If the "backlight" flag is set (in the case of "backlight"), the backlight is determined from the sub-subject brightness B■^. Luminance after subtracting the judgment reference value δ (
Compare BvA-δ) and camera shake limit brightness BvH #16
10) If (BvA-δ)≧Bvll, set the "transparent" flag indicating backlight on a bright background (#
1615), proceed to #1800 of the "backlight flash mode" routine ■, if (BvAδ) (I3vH,
Since it is a backlight in a dark background, proceed to #1675 of "Dark Flash Mode J Routine ■".

Next, the "natural light mode" will be explained.

First, check whether the "forced flash J" flag is set (#1620). If the flag is not set, then check whether the "transparent" flag is set (#1625), ” flag is not set, the control I3 v gi[i v■ is set to the average brightness Bvs'
#1630), and set the correction amount ΔEvil to 0 when directly metering the main subject brightness (
#1635). If the "transparent" flag is set in #1625, the background is brightly backlit, so set the control Bv value BvT to a value obtained by correcting the main subject brightness Bvs by +0.5, that is, BvT = Bvs + 0.5. #164
0), and the correction amount ΔEvtlL is set to <0.5-cz) (#1645). Note that α is the correction amount shown in Table 1, and its value changes depending on the imaging magnification β.

Next, control Bv value BvT and minimum brightness Bv that can be photographed
Compare #1650), and if BvT≦BvL, the shooting screen is too dark, so set the "No shooting" flag #1660), display the "No shooting" flag in the finder (#1665), and set ” subroutine to prohibit photography (#1670), BvT > B
If you have vL, please set the flash unnecessary flag #1
655), return to main routine (#1795)
).

Further, if the "forced flash J" flag is set in #1620, the flash mode is in effect, and the process proceeds to #1675 of the "dark flash mode" routine (2).

Next, "Dark Flash Mode J Routine (3)" will be explained.

First, check whether the "Flash Prohibit" flag is set (#1675). If the flag is set, it means that you are shooting in natural light, so proceed to #1625 of the "Natural Light Mode J Routine ■" flag is set. If not,
Brightness with main subject brightness Bvs corrected by +1.0 (Bvs+
1) and camera shake limit brightness Bvll #1680
), the setting of the control Bv value is switched depending on the brightness of the main subject. In other words, if Bvs+1≧BvH, set the brightness (Bvs+1> that is the main subject brightness Bvs corrected by +1°0 to the control Bv value BvT #1685), Bv
If s+1<BvH, the main subject brightness is lower than the camera shake limit brightness, so the control Bvff B v T is fixed at the camera shake limit brightness BvH (#1690).

Next, the correction amount ΔEvF of the exposure amount due to flash emission
Assuming that the coefficient K added to L is 0 (#1695), the value of the photographing magnification β is classified into three types (#1700), and the correction amount ΔE of the exposure amount due to flash emission is calculated for each of them.
Set vFL (#1705 to #1715), that is, if β>(1/25), set the correction amount ΔEvF to 0. #1705), <1/25)≧β>(11
55), then the correction amount ΔEvF is (0,5-K)
#1710), if (1155)≧β, then
The correction amount ΔEvFL of the exposure amount due to flash emission is (1
0-K) (#1715). This is to correct the fact that the size of the main subject on the photographic screen changes depending on the imaging magnification β, and the amount of exposure due to flash emission also changes.

Next, the above correction amount ΔE is added to the maximum light emission amount of the flash 1v.
Flash light emission amount rv (=Iv+Δ
Furthermore, the aperture value AvD is calculated from the above Iv'', film sensitivity Sv, and subject distance information Dv using the following formula (#1720). That is, AvD = r v' +5v-Dv = Iv+5v -Dv+ΔEvF Next, compare the aperture value AvD obtained in #1720 with the aperture value Avoz corresponding to the focal length at that time, and determine whether the distance to the subject exceeds the limit that the flash light can reach (
#1725), if AvD>AvD2, a "remote" warning is issued (#1730) indicating that the distance to the subject exceeds the limit that the flash light can reach, and the "remote" flag is set. (#1735), aperture value AvD
Set to Avoz (#1740), AvD≦AVO
If it is Z, do nothing and set the aperture value AvD to Avoz (#1740).

Next, the brightness BvH (-TvH+AvD -3v) calculated from the aperture value Avd obtained from #1740, the maximum shutter speed TvH, and the film sensitivity Sv and #16
Control B v fii set in 85 or #1690
Compare with B v T #1745), BvT≦Bv
If it is H, proceed directly to #1765 and perform the above control B.
The flash light emission timing time Tv is calculated using v fM B v T. If BvT>BvH,
Check if the “transparent” flag is set #1750
), if the flag is not set, proceed to #1765; if the flag is set, set the control Bv value BvT to (TvH + AvD - 3v) (#1755),
Main subject brightness Bvs and control Bv & obtained in #1755
Compare fBvT (=TvH+AvD-3v) (#1760), and if Bvs≦BvT, proceed to #1765 and calculate the flash light emission timing time Tv using the control Bv value BvT set in #1755. Further, if Bvs>BvT, the process proceeds to #1620 of the "natural light mode" routine (2).In addition, in #1765, the flash light emission timing time Tv is calculated from the following formula.

Ev=BvT +Sv Tv=Ev-AvD=BvT 15v-AvD Next, compare the flash timing time Tv calculated in #1765 with the maximum shutter speed TvH or camera shake limit shutter speed TvH. 1770.
#1780) If Tv≧T v H, it is the time when flash emission cannot be controlled, so the timing time T
Set v to the highest shutter speed T v H (#1
775), if Tv≦T v tl, there is a risk of camera shake occurring before the flash fires, so the timing time Tv is set to the camera shake limit shutter speed T v
Set it to It (#1785), set the "flushing required" flag #1790), and return to the main routine (#1795), TvH<Tv<T.
If it is vH (#1770, #1780), #1765
Using the Tv obtained in step #1790 to #1795.

Next, routine (3) of the "backlight flash mode" will be explained.

First, check whether the "light emission prohibition" flag is set (#1800), and if the flag is set, proceed to #1625 of the "natural light mode" routine (2). If the "flash prohibition" flag is not set, control B v
viB v T from the sub-subject brightness Bv^ by the correction amount 1.
OEv minus value, i.e. BvT = BvA-1,0
#1805), and the above control Bv (ifiBvT
and the main subject brightness BvS, that is, the brightness difference ΔEvN (-Bvs-B
vT) #1810), the above luminance difference ΔEvN
and -1°OEv (#1815), ΔEvN>
-1,0, fix ΔEvN to -1,0 and set the control Bv value BvT to the main subject brightness Bvs with a correction amount of 1 and OEv
The added value, that is, set BvT = Bvs + 1.0, and if ΔEvN≦-1,0, #1805 and #18
BvT set in 10 =Bvs+1', o and ΔIF,
Use vN=Bvs-BvT.

Then, the correction amount ΔEvF of the exposure amount due to flash emission
Set the coefficient K added to L to the value of α #1825)
, the process proceeds to #1700 above, and the processing from #1700 described in "Dark Flash Mode" is performed.

By the way, in the "backlight flash mode", a predetermined timing time Tv for flash emission is calculated from the brightness of the sub-subject (however, when δ≦Bv≦2, the timing time for flash emission is calculated from the main subject brightness), and the exposure is After the start, the flash is emitted after a predetermined time Tv has elapsed, and the exposure is stopped when the main subject is properly exposed, thereby adjusting the balance of brightness between the main subject and the secondary subject in the background. In the embodiment, since the exposure is stopped when the main subject becomes suitable after emitting the flash, the main subject becomes suitable, but the sub-subject becomes overexposed by the flash emission time.

Therefore, the present invention is not limited to the above-mentioned embodiment, and a second embodiment will be described below, which can accurately adjust the balance of brightness between the main subject and the sub-subject. That is, a certain correction time X [seconds] is calculated from the brightness difference between the main subject and the sub-subject, and
The flash is emitted X [seconds] before v elapses.

The value obtained by converting the above predetermined time Tv into [seconds] is X'',
If the timing time of flash emission is x' (seconds) after correcting the fixed time X from the same x'', then X'' == 2
T V (seconds) x' = x'' -

FIG. 8(b) shows a second embodiment using the predetermined time period X' for flash emission in the above-mentioned "backlight flash mode".
This will be explained using a flowchart.

The flowchart in FIG. 8(b) is inserted between #1765 and #1770 in FIG. 8(a).

First, in #1765, the flash emission timing time T
After v is calculated, check whether the "transparent" flag is set (#1895); if not, proceed directly to #1770; if the flag is set, check whether the "transparent" flag is set. From the brightness difference ΔEvN, a corrected amount ΔBvF for the amount of flash light is calculated from the following equation (#1900).

ΔB v M > ΔEvF=Iog2 (12 Next, the required flash emission amount 1v from the main subject distance
Calculate s from the following formula (#1905>.

I vs=Avoz+Dv-3v Next, compare the flash light emission amount Ivs obtained in #1905 with the actual light emission amount 1v. #1910) Ivs≦Iv
If so, calculate the correction amount ΔEvF ' obtained from the distance information obtained from the main subject distance and the appropriate correction amount ΔEvF for the flash light amount from the following formula #1915), and calculate the correction amount ΔEvF from the table shown in Table 4. The correction time X corresponding to ' is determined (#1940>.

ΔEvF ′=Ivs−Iv+ΔBvF Also, I v
If s > I v, the light emission Jilv is corrected by adding the brightness difference correction amount ΔEvF to the flash light emission amount Ivs.
Calculate s' (=Ivs+ΔEvF) #1920
), the correction amount ΔEvF' is calculated from the difference between the light emission amount Ivs' and the actual light emission amount Iv (#1925). That is, ΔEvF' = Ivs'-1v Next, check whether the above correction amount ΔEvF' is less than or equal to OEv (#1930), and if ΔF, vF'>O, ΔE
vF ′ should be set to 0 (#1935), ΔEvF ′≦
If it is 0, use the unchanged ΔEvF′ and #19
Proceed to step 40, and from the table shown in Table 3, correct indigo colors F, v
Determine the correction time corresponding to F'.

Next, the flash emission timing time x' [seconds] is calculated from the X obtained in #1940 and the predetermined time Tv using the following formula (#1945).

x'=2''-x Next, convert the flash emission timing time X [seconds] into Tv (Ev) using the following formula, and proceed to #1770 (#
1950).

Tv=log2 (1/x') This completes the explanation of the second embodiment, and next, the "release" subroutine of #2000 (#1005 in FIG. 6) will be explained using FIG. 9.

The "release" subroutine is comprised of routines for "natural light mode,""flashmode," and "forced flash mode."

First, switch the switch SWI to designate the photometry sensor as the light receiving section 17a (spot photometry at the center of the shooting screen) (#
2005). This is to control the exposure of the solid-state image sensor 9 to stop when the main subject becomes appropriate, so the sensor for photometry is set to spot metering at the center of the shooting screen.6 Next, shoot with #2010 and $2015. The modes are divided into "natural light mode", "flash mode", and "forced flash mode J". If the "forced flash J flag" is set in #2010, the program proceeds to the "forced flash mode" routine of #2235 to #2275. (described later), if the "flushing required" flag is set in #2015, #2
The process advances to the "flash mode" routine from 090 to #2230 (described later), and if the "flash required" flag is not set, the process advances to the "natural light mode" routine from #2020 to #2085.

When shooting in natural light mode (#2020), first, the ISO sensitivity is corrected by the main subject brightness correction value ΔBvH and the imaging sensitivity variation correction value γ (#2025), and then the timer Tl and timer T2 are set to -T v H Maximum shutter speed tM (=2) of 2
Division value to and camera shake limit shutter speed th (=2-
TvH and start the countdown, and at the same time, start the exposure of the solid-state image sensor 9 (#2
030), then time t.

It is confirmed whether the exposure amount of the solid-state image sensor 9 reaches an appropriate level by the time the period of time has elapsed. In other words, check that timer T1=0.#
2035), if TI>O, the voltage 1ifiV (hereinafter referred to as exposure voltage value) of the capacitor C of the circuit 22i that detects that the amount of charge accumulation in the solid-state image sensor 9 has become appropriate and the reference voltage value ■0. Compare #2040), V
If o<V, the charge accumulation amount has not reached the appropriate value, so return to #2035, check timer T1 again, and check ■0≧
If it is V, the amount of charge accumulation has reached the appropriate value, but the charge accumulation will be excessive until time tH, so set a flag to correct the gain of the captured image by -1 or 0 (#
2045), proceed to #2280 to #2290, close the shutter, and set the gain correction value -1°0 to the video processing control circuit 25.
and return to the main routine.

If it is T1-0 in #2035, timer 1-1 is set to t again.
Set o to start the countdown, and then set the time t.
Check whether the exposure amount of the solid-state image sensor 9 reaches the appropriate amount by the time o elapses (#2250 to #2060), time to
If the solid-state image sensor 9 reaches the proper exposure before time tH elapses, charge accumulation will be excessive until time tH, so a flag is set to correct the gain of the captured image by -0.5 (#2045). , proceed to #2280-#2290,
The shutter is closed, the gain correction value -0, 5 is output to the video processing control circuit 25, and the process returns to the main routine.

If the solid-state image sensor 9 does not reach the proper exposure by the time the time to has elapsed (T1=O in #2055), then the time tH
Check whether the solid-state image sensor 9 reaches proper exposure between ~t11 (#2070, #2075), that is, vO≧
If it is (#2070), the solid-state image sensor 9 has reached the appropriate exposure, so the shutter is closed (#2280), and since there is no gain correction, the gain correction value 0 is set to the image processing control circuit 25.
(#'2285) and returns to the main routine (#2290). If Vo<V, T2=O(
Check whether the time t11 has passed) #2075), T
If 2=O, the exposure time of the solid-state image sensor 9 exceeds the camera shake limit time, so the charge accumulation of the solid-state image sensor 9 is forcibly stopped (#2080), and the gain of the captured image is adjusted to compensate for the lack of exposure. Set a flag to correct the gain by +0.5 (#2085), close the shutter (#2280), output the gain correction value +0.5 to the video processing control circuit 25 (#2285), and return to the main routine (#2285). 2
290).

Next, to explain the flash mode (#2090), as in the natural light mode, first, the main subject brightness correction value ΔEvFL and the ISO sensitivity Sv corrected by the imaging sensitivity variation correction value γ are input to the D/A conversion circuit. 22h
(#2095).

Next, check whether the "backlight" flag is set (#2100), and if the flag is set, check #215
Proceed to "Backlight" flash mode shooting (described later) in 5 to #2230, and if it is not set, proceed to #2105 to #2230.
Performing normal flash mode shooting with the 2150 0 In normal flash mode shooting, timer 1゛1 and timer T2
Set the Tv flash light emission timing time t^ (=2) and camera shake limit shutter speed tH, respectively, and set the timer T.
At the same time as starting the countdown of 1 and T2, exposure of the solid-state image sensor 9 is also started (#2105). Next, T1
Exposure with natural light is performed until =O (time tA elapses), and when T1 = 0, the flash is emitted (
#2110 to #2115), and at the same time, the timer T3 is set to the flash emission time tF, and a countdown is started ($2120). During flash emission (T3>O), the reference voltage value ■0 is compared with the exposure voltage value V, and if Vo≧V (#2125 to #2130), the solid-state image sensor 9 has reached the appropriate exposure, so #2280~#
Proceeding to 2290, the shutter is closed, and since there is no gain correction, a gain correction value of 0 is output to the video processing control circuit 25.
Return to main routine.

Next, if V o < V and proper exposure is not achieved during flash emission, the solid-state@imaging element Check if 9 reaches the proper exposure (#213
5~#2140). Once the proper exposure is reached, (#2140
), the process proceeds to #2280 to #2290 in the same way as #2130, closes the shutter, outputs a gain correction value of 0 to the video processing control circuit 25 since there is no gain correction, and returns to the main routine. Camera shake limit time LH elapses (T2
= 0), when the time t[1 has elapsed, the charge accumulation in the solid-state image sensor 9 is forcibly stopped #2145>, and the gain of the captured image is adjusted to compensate for the insufficient exposure. Set a flag to correct +0.5 (
Proceed to #2150) and #2280 to #2290, close the shutter, and set the gain correction value 10.5 to the video processing control circuit 2.
5 and return to the main routine.

Next, the "backlight" flag is set in #2100, and when shooting in "backlight" flash mode, the "backlight" flag is set.
Make sure the "Remote" flag is set #2155
), if the flag is not set, set the flash firing timing time ta in timer 1 #2
160), when the flag is set, timer T
The timing time of flash emission is 8' (-tA/
2) is set (#2195), a countdown is started, and at the same time, exposure of the solid-state TFAR element 9 is also started.

If the "remote" flag is not set, when the flash emission timing time tA has elapsed (#2165
), the flash is emitted (#2170), and at the same time, the timer T is set to the flash emission time tf, and a countdown is started (#2175). Then, if the solid-state image sensor 9 reaches proper exposure (#2180, #2190) during flash emission ('r>0), #2280 to #229
0, the shutter is closed, and since there is no gain correction, a gain correction value of 0 is output to the video processing control circuit 25, and the process returns to the main routine. If proper exposure is not obtained during flash emission, charge accumulation in the solid-state image sensor 9 must be forcibly stopped after the flash emission (after time tF has elapsed) #2
185), close the shutter without setting the gain correction flag for the photographed video (#2280), output a gain correction value of 0 to the video processing control circuit 25 since there is no gain correction (#2285), and Return to the routine (#2290).When shooting in the "backlight flash mode" in #2160 to #2185, the background is brightly backlit, so even if you forcibly stop the exposure in #2185, the gain correction of the captured image will not be performed. .

Even when the "remote" flag is set, the flash is fired after the flash emission timing time has elapsed, and the solid-state image sensor 9 When the exposure is appropriate, the shutter is closed, and since there is no gain correction, a gain correction value of 0 is output to the video processing control circuit 25, and the process returns to the main routine (2200 to #2220. #2
280~#2290). If proper exposure is not obtained during flash emission, the charge accumulation in the solid-state image sensor 9 is forcibly stopped after the flash emission #2145), and a flag is set to correct the gain of the captured image by +1.0 (#2145). 4
t2230), closes the shutter (#2280), and outputs the gain correction value +1.0 to the video processing control circuit 25 (#
2285), return to the main routine (9229
0).

In #2195 to #2230, when shooting in the "remote""backlight flash mode", the exposure time using natural light is half of the time t^ when shooting in "backlight flash mode", so the exposure is forced in #2225. When stopped, the gain correction of the captured video is +1°0.

Next, to explain the forced flash mode (#2235>, first, the main subject brightness correction value ΔEv[[ and the ISO sensitivity Sv corrected by the imaging sensitivity variation correction value γ are output to the D/A conversion circuit 22h. (#2240).Next, the maximum shutter speed tH and camera shake limit shutter speed tH are set in the timers T1 and T2, respectively, and at the same time as the timers T1 and T2 start counting down, the exposure of the solid-state image sensor 9 is also started. (#2245
). Next, when the maximum shutter speed tH has elapsed (
'I'1=O), use the flash #2250~#
2255), camera shake limit time tH has elapsed<T2=O
) It is confirmed whether the solid-state image sensor 9 reaches the appropriate exposure by (#2260 to #2265). If the proper exposure is reached before the camera shake limit time tH elapses, the shutter is closed (#
2280), and since there is no gain correction, a gain correction value of 0 is output to the video processing control port v@25 (#2285), and the process returns to the main routine (#2290). If the proper exposure is not reached, when the camera shake limit time th has elapsed (T
2 = O), force the charge accumulation of the solid-state image sensor 9 to stop #2270), and set a flag to correct the gain of the captured image by +0.5 to correct the underexposure #2275) , close the shutter (#2280),
Output the gain correction value 0.5 to the video processing control circuit 25 (#2285) and return to the main routine (#2290>).

This concludes the explanation of the release sequence operation.

In this embodiment, in order to downsize and reduce the cost of the device, the flash light emission stop circuit is omitted so that the flash always emits full light.

However, in order to save power, the flash may also stop emitting light when the exposure is stopped.

(Hereafter, margin) No. table note) [Main]: Main subject brightness.

Bvs’ : Average brightness value of the shooting screen note) No. table tf: Akebono 11 with a flash

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an optical system of an electronic camera according to an embodiment of the present invention, FIG. 2 is a system configuration diagram of the electronic camera, and FIG. 3 is a time diagram for explaining exposure time and flash emission timing. 4 is a flowchart of the main program for controlling the camera section of the electronic camera, FIG. 5 is a flowchart for executing the initial load applied to the main program, and FIG. 6 is a flowchart for executing the initial load applied to the main program. FIG. 7 is a flowchart for executing the AP applied to the flowchart of S1, and FIG. 8(a) is a flowchart of the MJ optical AE applied to the above flowchart. FIG. 8(b) is a flowchart for explaining the second embodiment of the flash emission timing according to the present invention, and FIG. This is a flowchart of the steps to be executed. 6... Photometric sensor, 9... Solid-state image sensor, 10...
・System controller, 18... Fuller ・191 circuit, 22... Control IC 123... System controller, S13... Forced flash switch, Fig.

Claims (1)

[Claims] (1) A selection means for selecting either a forced-flash mode in which the flash is forced to fire or a normal mode in which it is not forced to fire; a photometer for measuring the brightness of the subject; and a flash that determines the timing to fire the flash based on the photometry information. It is equipped with a light emission control means and an electronic shutter control means that closes the shutter when the appropriate exposure is reached after opening the shutter.When the normal mode is selected, the flash emission timing is determined based on the photometric information of the subject. Decide and fire the flash,
The shutter is closed when the appropriate exposure is reached, and when forced flash mode is selected, the flash is fired at the timing of the shutter opening, and the shutter is closed when the appropriate exposure is reached. Flash emission control device for electronic still cameras.