JPH0358037A - Multiple-dimming camera - Google Patents

Abstract

PURPOSE:To facilitate operations and to take a well balanced photographing by operat ing a range-finding means even when the function of maintaining a range ring is active, and obtaining each focal point information immediately before releasing. CONSTITUTION:A camera possesses a photometric circuit 7 for carrying out photometry in the plural areas in a objective field under the control of a microcomputer (muP) 1, a focal point detecting circuit 6 for range-finding the plural areas, and a lens driving circuit 2 for controlling the driving of the range ring of a lens to a well focused position obtained from each focal point information from the circuit 6, etc., and the function of maintaining the range ring at the well focused position. Even when the function of maintaining the range ring is active, the focal point detecting circuit 6 is operated and each focal point information just immediately before the releasing is inputted into the storobo light flashing and dimming control circuit 5 though the MUP 1. In the circuit 5, each photometric value from a photometric circuit 7 is evaluated based on this information and flash light emitting quantity is decided. Thus, even when framing is changed after a well focused state is maintained, appropriate exposure is attained without carrying out troublesome operations and a picture well balanced with a background can be taken.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention measures the reflected light of light projected toward a subject from a flash emitting unit in a plurality of areas, and adjusts the flash light emission according to these photometric values. This invention relates to a multi-flash control camera that determines the amount of light emitted by each section.

(Background of the Invention) Conventionally, a flash light emitting unit is emitted toward a subject, and the reflected light from the subject is measured to determine the intensity (light amount) of the reflected light.
There are many cameras on the market that control the amount of light emitted depending on the amount of light emitted.

However, most cameras use a single metering sensor to meter the light in the center of the screen and adjust the light, so if the main subject is located in the center of the screen and is of an appropriate size, it is suitable for shooting. However, if the main subject is not located in the center of the screen or is small relative to the screen, there is a problem that it will not be possible to obtain an appropriate exposure due to the influence of the amount of light in the background. there were.

In view of this, JP-A-60-108827 proposes a multi-flash control camera in which a plurality of photometric sensors are arranged and each is variably controlled to determine (control) the amount of light emitted. The photographer must use an external operation to determine which area to focus on when metering, and this operation is cumbersome.

Furthermore, in JP-A No. 55-135823, by measuring the light of multiple areas of the screen when there is no flash and when there is a flash, and comparing these light measurement values, it is possible to take pictures of the subject closest to the camera. An area with an image was selected, and the amount of light emitted was controlled by the photometric value of that area. With this method, the exposure will be appropriate for the closest object, but if the main subject is not the closest, the exposure will not be appropriate for the main subject, and the balance with the background will also be considered. It wasn't.

Furthermore, in US Pat. No. 4,796,043, etc., a method has been proposed in which multiple areas of the screen are individually photometered and exposure is performed based on the photometric value of the area corresponding to the distance measurement area. There is no mention at all of photometric evaluation. Photometric evaluation of a subject illuminated by flashlight emission differs greatly from photometry of steady light, as it differs greatly depending on the distance of the subject from the flashlight emitting unit, the duration of flashlight emission, etc.

Furthermore, most cameras in recent years have an AF mode (hereinafter referred to as one-shot mode) that maintains focus once focus is achieved, but when using this mode, for example, when the main subject is It is possible to take a picture by bringing it to the center, measuring the distance, then changing the framing and taking the picture (the information at the time of distance measurement is used for focusing). If the main subject is not located nearby, the exposure will not be appropriate for the main subject, and even if the main subject is located closest to the subject, the photograph will not necessarily be well-balanced with the background.

(Objective of the Invention) An object of the present invention is to solve the above-mentioned problems, and to enable the main subject to be properly exposed without any troublesome operations even if the 71 norming is changed after maintaining the focus. To provide a multi-flash control camera capable of taking photographs well-balanced with the background.

(Characteristics of the Invention) In order to achieve the above object, the present invention operates the distance measuring means even when the distance ring holding function is working, obtains each focus information immediately before release, A light control means is provided which evaluates each photometric value from the photometric means based on the respective focal point information and determines the amount of flash light emitted. The feature is that the amount is controlled.

(Example of the invention) FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, 1 is a microcomputer that controls the movement of each part of the camera, and 2 is a lens control circuit that drives and controls a focusing motor and an aperture blade control motor of a photographing lens (not shown). 2 performs serial communication via the data bus DBtlS while receiving the LCOM signal from the microcomputer 1, and when motor drive information is received through serial communication, it drives and controls the aforementioned motor (not shown) using that information. . At the same time, the lens control circuit 2 sends various information about the lens to the microcomputer 1 through serial communication.

Reference numeral 3 denotes a liquid crystal display circuit for driving a liquid crystal display (not shown) for informing the photographer of various shooting information of the camera, such as shutter speed and aperture value, and receives a DPCOM signal from the microcomputer 1. During this time, serial communication is performed via the data path DBUS, and when display data is received through serial communication, the liquid crystal display is driven in accordance with the display data.

4 is a switch sense circuit that reads the status of switches used by the photographer to set various shooting conditions and switches that indicate the status of the camera and sends it to the microcomputer l;
While receiving the WCOM signal, the data bus l) BIIS
The microcomputer l by serial communication via
The data of the various switches mentioned above are sent to.

5 is a strobe light emission control circuit that controls the strobe light emission and the light emission stop function by TTL adjustment;
While receiving the signal, serial communication is performed with the microcomputer 1 via the data path DBIJS, and various controls are performed by receiving data related to strobe control.

Reference numeral 6 denotes a focus detection circuit which is a unit consisting of a line sensor for performing AF using the existing phase difference detection method and a circuit for accumulating and reading out the line sensor, and is controlled by the microcomputer 1.

Reference numeral 7 denotes a photometry circuit that performs photometry of the subject under the control of the microcomputer 1, and the photometry output obtained here is sent to the microcomputer 1, where it is A/D converted and used to set exposure conditions. .

Reference numeral 8 denotes a shutter control circuit that controls running of the leading shutter curtain and rear curtain (not shown) according to control signals from the microcomputer 1.

A feeding circuit 9 controls a feeding motor (not shown) according to a control signal from the microcomputer 1, and winds and rewinds the film.

10 is turned on at the timing when the front curtain of the shutter completes its travel.
This is an X contact that has the role of informing the strobe light emission control circuit 5 of the strobe light emission timing.

SWI is a switch that moves with the release button of the camera, and when the microcomputer 1 recognizes that the switch SWI has been turned on, the microcomputer 1 starts an exposure operation.

FIG. 2 is a block diagram showing an example of the configuration of the strobe light emission control circuit 5. As shown in FIG.

In the figure, 5l is a control circuit that exchanges data with the microcomputer 1 through serial communication and controls the dimming circuits 52, 53, and 54 and the strobe 55.

The dimming circuits 52 to 54 each include a logarithmic compression amplifier, an expansion transistor, an integral capacitor, etc., or a TTL
Light control is started by the R signal, photoelectrically converted by a photodiode (hereinafter referred to as light control sensor) PD, and the image plane light amount of the input film surface is amplified by a logarithmic compression amplifier, and TTL
A gain is applied by the expansion transistor according to the value of the G signal (gain information for dimming), and the signal is integrated by the integrating capacitor.

When the charge on the integral capacitor exceeds a predetermined value, a CMP signal is output to the control circuit 51. The strobe 55 is an existing one, and when sufficient charge for light emission is stored, the FVL signal notifies the control circuit 5l of completion of charging. When the STA signal is sent from the control circuit 51 that receives this, it starts emitting light, and when the SPT signal is sent thereafter, it stops emitting light.

FIG. 3 shows the sensitivity area of the dimming sensor PD and the sensitivity area of a focus detection line sensor, which will be described later.

The light control sensor PDI-3 is arranged facing the film surface of the camera, and has a sensitivity area as shown in FIG. 3 with respect to the screen. Also, the focus detection line sensor LSI ~ 3, which will be described later.
has sensitivity areas as shown in FIG. 3 on the screen by an optical system (not shown), which correspond to the sensitivity areas of the dimming sensors PDI to 3, respectively.

FIG. 4 is a diagram showing an example of the structure of the focus detection circuit 6 shown in FIG. It is made up of circuits.

Next, the camera operations after the focus detection operation will be explained using FIG. 4, etc. In response to the (1:Ls}I signal from the microcomputer 1, the line sensors LSI to LS3 each perform photoelectric conversion and start accumulation. When the maximum of the accumulated charges of the line sensors LS1 to LS3 reaches a predetermined value, the focus detection units 61 to 63 output an FB signal and stop accumulation, and sample and hold each accumulated charge. The microcomputer 1 controls all focus detection units 6.
When detecting that the FB signal has returned from 1 to 63,
The focus detection unit 6 outputs the φ signal (clock signal).
1 to 63 sequentially sample and hold accumulated charges according to the φ signal and send them to the microcomputer 1 as a DLS signal. The microcomputer 1 receiving the DLS signal A/D converts this signal, performs predetermined calculations, and performs serial communication with the lens control circuit 2 based on the calculation results.
The lens control circuit 2 drives a focus adjustment motor based on the sent data. At this time, various proposals have been made regarding which area to focus on among the sensitivity areas of the line sensors LSI to LS3 on the screen. For example, you can focus on the object closest to you, or you can focus so that all areas are within the depth of field.

When the AF operation as described above is completed, the microcomputer 1 sends information such as which zone is in focus and which zone is within the depth of field to the strobe light emission control circuit 5. Then, the control circuit 51 in the circuit 5 adjusts the light control circuits 51 to 5 based on the sent focus information.
Send dimming gain information (TTLG signal) to 3. After that, when the X contact 10 is turned ON, the control circuit 51 starts the strobe 55 to emit light using the STA signal, and at the same time, the TTLR
The signal starts dimming. and dimmer circuits 52-5
When the CMP signal is sent from 4 to complete the dimming,
The STP signal causes the strobe 55 to stop emitting light.

Focus on each zone. Figure 5 shows the relationship between out-of-focus and dimming gain, as well as the relationship between the CMP signal and STP signal. The control method shown in Figure 5 is just an example, and the dimming gain setting is You can choose from an infinite number of options depending on the focusing conditions, such as ``appropriateness'', ``under a predetermined stop'', and ``over a predetermined stop''. Also, the light emission stop control is rOR (logical sum).
Not only r A. N D (logical product)” (CIII
You can also select to output the STP signal when all signals P1 to P3 arrive. Further, when the light control correction is applied, the light control gain correction may be applied to both the in-focus zone and the out-of-focus zone, or the light control gain correction may be applied only to the focus zone. FIGS. 6(a) to 6(c) are flowcharts outlining the flow of a series of camera operations and diagrams to help explain the operations. Switch sensing is performed in step 1, photometry is performed in step 2, and display (photometry information, etc.) is performed in step 3. In the next step 4, a distance measuring operation is performed, and the process proceeds to step 5. In step 5, select the current AF mode and maintain focus. Determine the non-retention state and predictability state and return to step 4, or step 6
Or, it is determined whether to proceed to step 7 (see Fig. 6(b)). In other words, in AP one-shot mode (a mode in which the focus is maintained once the focus is achieved), when the focus is already maintained, the lens distance ring is not driven and the process immediately proceeds to step 7, and when the focus is not yet maintained. The process proceeds to step 6, where the lens distance ring is driven to maintain focus, and the process proceeds to step 7. In addition, when in AF prediction servo mode (a mode that predicts the movement of the subject so that it will be in focus at the time of release), if it is determined that the number of distance measurements is insufficient for prediction, return to step 4 and perform distance measurement. When it is determined that the distance measurement has been repeated repeatedly to make a prediction, the process proceeds to step 6, where the lens distance ring is driven to maintain focus, and the process proceeds to step 7. When the release button is not pressed, the sequence from step 1 to step 7 is repeated.

When the release button is pressed, the process advances from step 7 to step 8, and the following sequence is performed. In step 8, distance measurement is performed, and in step 9, the AF mode is determined. As a result, if the mode is AF full shot mode, the process immediately proceeds to step 11 without driving the lens distance ring, while if it is AP prediction third, the process proceeds to step 10, and at the time of release (during exposure) The position of the subject is calculated and predicted based on the distance information up to that point, the lens distance ring is driven to the predicted focus position, and the process proceeds to step 11 (see FIG. 6(c)). In the next step 11, the dimming level is set. In the AP one-shot mode, the dimming level is set based on the focus information (in-focus/out-of-focus information) of each area based on the latest distance measurement. Furthermore, in the AF prediction servo mode, the focus state of each area at the time of release (during exposure) is predicted, and the AF prediction is performed based on this information. When preparations for dimming control are completed, the process proceeds to step 12, where shutter control is performed, that is, the shutter is controlled to expose for a predetermined period of time. At that time, the strobe light is emitted and stopped. When the release is finished, one frame of film is fed for the next shooting.

FIG. 7 is a block diagram showing a strobe light emission control circuit in another embodiment of the present invention, and the other circuits constituting the camera are the same as those in FIG. 1.

The control circuit 51, photometric sensors PD1 to PD3, light control circuits 52 to 54, and strobe 55 are almost the same as the strobe light emission dimming control circuit shown in FIG. 2 in the embodiment, but an addition circuit 56, The major difference is that a level detection circuit 57 is added. The light control circuits 52 to 54 output L'/Ll to 3 signals, which are the integrated values to the integral capacitor, without outputting the CMP signal. The adder circuit 56 logarithmically transforms the LVLI~3 signal,
An ADL signal which is the added value is output. When the ADL signal exceeds a predetermined value, the level detection circuit 57 detects the CMP
Output a signal. The operation of the control circuit 51 is the same as in the previous embodiment, including setting of dimming gain information (TTLG signal),
Start of light emission of strobe 55, start of dimming operation, and CM
It performs operations such as stopping the light emission of the strobe 55 in response to the input of the P signal.

The dimming gain is set so that the CMP signal is output when the desired amount of image plane light is reached in each zone.

Further, even if the amount of light on the image plane is the same, the balance of each zone changes by changing the weighting of the dimming gain in each zone. The situation will be explained with reference to FIG.

In the example of FIG. 8(a), when each zone is properly exposed, l,
The dimming gain information (TTLG signal) is set so that the value obtained by logarithmically converting the VL signal becomes r3:1:IJ. When the weighted zone of the light control sensor PDI becomes one step over, and when the zones of the photometric sensors PD2 and PD3 each become -1.5 steps under, a CMP signal is output. In other words, zones that have been weighted will not be affected too much even if zones that are not weighted are too bright or too dark, and will be able to obtain an exposure close to the appropriate amount, and zones that have not been weighted will also be able to obtain an exposure that is close to the appropriate exposure. Since you can get an exposure that is not far off, you can get a well-balanced exposure for the entire screen. The example in Figure 8(b) is the same. In this other embodiment, the weighting of the dimming gain is changed depending on the in-focus/out-of-focus information of each zone. i.e. the focus zone,
By weighting the zone within the depth of field as shown in Figure 9, it is possible to take a well-balanced strobe photo with an appropriate exposure for the main subject (the subject you want to focus on). According to this embodiment, by selecting the AP one-shot mode, it is possible to take a picture as shown in Fig. 10, but in such a case (when taking a picture where the frame is changed after maintaining the focus), Even if there is a problem, we measure the light in multiple areas within the screen and measure the distance to these areas immediately before release, evaluate the light metering value based on the focus information (in-focus/out-of-focus information) of each area, and calculate the amount of light emitted. Since the camera is configured to control the main subject, it is possible to predict the position and size of the main subject in the screen to a certain extent, and control the main subject so that the exposure is appropriate, and also provides a good balance with the background. It is possible to create a multi-flash control camera that can control the amount of flash light to provide the appropriate amount of exposure. That is, once the camera is in focus with AF, the main subject is located in the sensitivity area of the photometric sensor at the center of the screen, as shown in FIG. 10(A). If the photographer then moves the main subject to the left side of the screen, since it is AP one-shot mode, the AF will remain locked, that is, the focus will remain, and the situation will be as shown in Figure 10 (B). Therefore, the main subject is located within the sensitivity area of the left photometric sensor. When the photographer performs the release operation when the composition is determined, the focus state of each area is determined by distance measurement just before the release, and the focus state of each area is determined during exposure as shown in Figure 10 (Fig. 10).
As shown in C), the main subject is in the same position as in Figure 10 (B), so the focus state at the time of exposure can be determined, and based on this, each photometric value is evaluated and the amount of light emitted is controlled. This is because it is composed of

(Correspondence between the invention and the embodiments) In this embodiment, the focus detection circuit 6 is used as the distance measuring means of the present invention, and the light control circuits 52 to 54 and the photometric sensors PDI to PD3
is the photometric means, the lens control circuit 2 is the driving means, the control circuit 51 (FIG. 2), or the control circuit 51, the addition circuit 56.
The level detection circuit 57 (FIG. 7) corresponds to the dimming control means.

(Effects of the Invention) As explained above, according to the present invention, even when the function of holding the distance ring is operating, the distance measuring means is operated to obtain information on each focal point immediately before the release, and A light control means is provided which evaluates each photometric value from the photometric means based on each focal point information and determines the amount of flash light emitted. Since the focus is maintained, even if you change the framing, you can take photos with the main subject properly exposed and well-balanced with the background without any troublesome operations. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the structure of the strobe light emission control circuit shown in FIG. 1, and FIG. A diagram showing the relationship between the sensitivity area and the sensitivity area of the focus detection line sensor, FIG. 4 is a block diagram showing an example of the configuration of the focus detection circuit shown in FIG. 1, and FIG. 5 shows the focus state in an embodiment of the present invention. FIG. 6 is a flowchart showing a series of operations in one embodiment of the present invention, and FIG. 7 is a strobe light emission dimming control circuit in another embodiment of the present invention. A block diagram showing a configuration example of
FIG. 8 is a diagram showing changes in the image plane light intensity of each zone due to weighting of the dimming gain in another embodiment of the present invention, and FIG. 9 is a diagram showing changes in the focal state and dimming gain in another embodiment of the present invention. FIG. 10, a diagram showing the relationship, is a diagram for explaining the effects of each embodiment of the present invention. 2... Lens control circuit, 6... Focus detection circuit, 5... Strobe light emission control circuit, 5
1...Control circuit, 52-54...Dimmer circuit, 56...Addition circuit, 57...Level detection circuit, PDI-PD3... ...Photometry sensor.

Claims (1)

[Claims] (1) A photometer that measures the reflected light of a flash of light projected toward a subject in each of a plurality of areas, a distance measurement unit that measures the distance of each of the plurality of areas, and each focal point information from the distance measurement unit. In a multi-flash control camera, the multi-flash control camera is equipped with a driving means for driving a distance ring of a lens to a focus position determined from the focus position, and has a function of holding the distance ring at the focus position, when the function of holding the distance ring is operating. Even if there is, a light control control means operates the distance measuring means to obtain each focal point information immediately before release, evaluates each photometric value from the photometric means based on the focal point information, and determines the amount of flash light emission. A multi-flash control camera characterized by the following: