JPH0651378A - Camera - Google Patents

Abstract

PURPOSE:To allow a flash device to emit light by the smallest emitted light quantity when release is executed without loading a film and to suppress the consumption of a battery. CONSTITUTION:When the loading of the film is detected by a film detection means 103, a light control means 101 is actuated by a control switching means 104 and the emitted light quantity of the flash device 100 is controlled so that the exposure of an object on the film becomes proper. When it is detected that the film is not loaded, an emitted light quantity control means 102 is actuated and the emitted light quantity of the flash device 100 is controlled to the prescribed small light quantity which is not related to the exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera in which an electronic flash device can be built in or mounted.

[0002]

2. Description of the Related Art Conventionally, the following TTL automatic light control is performed in a camera having an electronic flash device or a camera having an electronic flash device. Immediately after the shutter is opened, the flash device starts to emit light, and the illumination of the subject is started.At the same time, the reflected light from the subject that has passed through the shooting lens and reflected on the surface of the film is received by the photoelectric converter in the mirror box, It is converted into an electric signal and amplified at an amplification factor according to the film sensitivity. Further, the amplified signal is integrated by a capacitor, and when the integrated value reaches a predetermined value, the flash device stops emitting light.

Further, TTL multi-dimming control, which is an improvement of the above-mentioned TTL automatic dimming control, is known (see, for example, Japanese Patent Laid-Open No. 3-68928). With this kind of camera,
The field of view is divided into multiple areas at the position where the film surface is viewed, and a plurality of photometric converters that can measure light are arranged.The flash device is pre-lighted immediately before opening the focal plane shutter, and the shutter passes through the shooting lens. A plurality of photoelectric converters receive the reflected light from the subject reflected on the surface of the curtain.
Then, the output signals of the photoelectric converters corresponding to the respective regions of the object scene are separately integrated, and the integrated values thereof are used as object scene reflected light distribution information by flash light emission. The detected field reflected light distribution information is arithmetically processed by a predetermined algorithm, and the degree of weighting for each divided area is determined so that the main subject has an appropriate exposure amount. Next, immediately after the shutter is opened, the flash device is caused to emit the main light, and the reflected light from the object field which has passed through the taking lens and reflected by the film surface is received by the plurality of photoelectric converters described above. Then, the output signal of each photoelectric converter is weighted in advance and added, and the added value is integrated. When the integrated value reaches a predetermined value, the flash device stops the light emission, and the dimming of the main light emission ends.

[0004]

By the way, at the time of normal photographing, a film is loaded into the camera and the shutter is released to take a photograph. However, the shutter may be released without loading the film. For example,
These are cases such as an empty release to familiarize yourself with how to use the camera, a test release to check the operation of the camera and the flash device before shooting, and a test release to explain the usage at the store.

However, in the conventional camera, the normal flash light is emitted by the flash device even in the case of the test release other than such photographing, and the TTL is the same as that at the time of loading even if the film is not loaded. Automatic dimming control is performed. As a result, the reflected light from the subject that has passed through the photographic lens is reflected by the black pressure plate provided on the back cover of the camera because no film is loaded, and enters the photoelectric converter. However, since the black pressure plate has a lower reflectance than the surface of the film, the amount of reflected light entering the photoelectric converter is lower than that when the film is loaded. For this reason, the camera determines that a larger flash light emission amount is necessary, and causes the flash device to emit light for a long time to increase the light emission amount. Also, TTL
Even in the multi-dimming control, the preliminary light emission prior to the main light emission is performed as in the case of loading the film. In this way, in the conventional camera, even when performing the test release without loading the film, the flash light is emitted with the light emission amount equal to or more than that in the normal photography with the film loaded, and therefore the battery power is saved. There is a problem of wasteful consumption.

In order to solve this problem, it is conceivable to prohibit the flash device from emitting light when the film is not loaded so that the flash device does not emit light even after the release. In that case, the flash device emits light during the test release. Can not be inspected, and the flash device does not emit light, which may lead to misunderstanding that it may have failed.

An object of the present invention is to make the flash device emit light with a minimum amount of light emission in the case of releasing without loading a film, and to suppress battery consumption.

[0008]

The invention according to claim 1 will be described with reference to FIG. 1 which is a claim correspondence diagram.
Of the invention, the dimming control means 1 for controlling the light emission amount of the flash device 100 so that the exposure amount of the subject to the film becomes appropriate.
Applies to cameras with 01. Then, the light emission amount control means 102 that controls the light emission amount of the flash device 100 to a predetermined small light amount that is irrelevant to the proper exposure amount, the film detection means 103 that detects loading and unloading of the film, and the film detection means 103 A control switching unit 104 that operates the dimming control unit 101 when the film loading is detected and operates the light emission amount control unit 102 when the film non-loading is detected is provided. To achieve. The light emission amount control means 102A of the camera according to claim 2.
Is a device in which the flash device 100 is caused to emit light for a predetermined short time. The flash device 100 of the camera according to claim 3.
A is built in the camera and is supplied with power from the battery of the camera. The invention of claim 4 is applied to a camera for controlling the light emission amount of main light emission at the time of exposure based on the result of detecting the reflected light distribution information of the field due to the preliminary light emission of the flash device before exposure, The above object is achieved by providing a film detecting means for detecting the loading, and not performing the preliminary light emission when the loading of the film is not detected by the film detecting means.

[0009]

In the camera of the first aspect, when the non-loading of the film is detected, the flash device 100 is caused to emit light with a predetermined small amount of light irrelevant to the proper exposure amount of the film. Further, in the camera of claim 4, when the loading of the film is not detected, the preliminary light emission is not performed.

[0010]

FIG. 2 is a sectional view of the camera of the embodiment. A camera 81 equipped with a built-in flash device 89 includes a movable mirror 83
The film 86 is placed on the inner rail 84 at a position where the light flux from the subject that has passed through the taking lens 82 in the retracted state forms an image.
It is fixed by a and 84b and the pressure plate 85. The front curtain 87 of the focal plane shutter is closed immediately before the film 86 to prevent exposure of the film 86 except during photographing, and shields the light. During the exposure, that is, when the shutter front curtain 87 is in the retracted state, the light flux from the subject is refracted by the taking lens 82 to form an image on the surface of the film 86,
A part of them is reflected and reaches the condenser lens 92 and the photoelectric converter 91. When exposure is not in progress, that is, when the shutter front curtain 87 is closed as shown in FIG. 2, the light flux from the subject is refracted by the taking lens 82 and is shutter front curtain 87.
The image is almost formed on the surface of, and a part of the image is reflected and reaches the condenser lens 92 and the photoelectric converter 91.

FIG. 3 shows a photoelectric converter 91 and a condenser lens 92.
It is a figure which shows the structure of. The photoelectric converter 91 includes a circular light receiving portion PD11 on the same plane, and light receiving portions PD21, PD31, PD41, which are formed by cutting out a rectangle with arcs on both sides thereof.
PD51 is arranged. The condenser lens 92 includes three lens portions 92a, 92a,
It is an optical member having 92b and 92c.

FIG. 4 shows the optical positional relationship between the aperture area 93 on the film surface, the photoelectric converter 91, and the condenser lens 92.
It is the figure seen from the A direction. Opening area 93 on the film surface
The central circular portion 93a and the peripheral portion are divided into four 93b, 93
When divided into five areas c, 93d, and 93e, FIG.
The central, left, and right three blocks of the light receiving parts PD11 to PD51 of the photoelectric converter 91 shown in FIG. 3 are three lens parts 92a to 92c of the condenser lens 92 as shown by the fine broken line, the one-dot chain line, and the coarse broken line, respectively. The center, the left half, and the right half of the film surface opening are respectively stared through through, and they are almost imaged. Furthermore, the five light receiving parts PD11, PD21, PD31, P of the photoelectric converter 91 of FIG.
Since D41 and PD51 have the same shape as the areas 93a, 93b, 93c, 93d, and 93e of the film surface openings of FIG. 4, respectively, they are photoelectric converters that divide the brightness of the five areas and perform photometry. ing.

FIG. 5 shows the configuration of the embodiment. Camera 81
Is a photometry / dimming circuit 11, a microcomputer 12,
D / A converters 21 to 25, light emitting section 51, light emission control circuit 5
It is composed of 2 etc. First, the photometry / dimming circuit 11 will be described. FIG. 6 shows the details of the photometry / dimming circuit 11. Light receiving parts PD11 to 11 configured by phototransistors
The PD 51 outputs a photocurrent proportional to the illuminance of the five areas 93a to 93e shown in FIG. The photocurrent output from the light receiving unit PD11 is converted into a voltage output logarithmically compressed by the OP amplifier A11 fed back from the diode D11 with the reference power source E1 as a reference. Transistors Q11, Q
12 uses this voltage as the emitter potential, and further uses the input voltage from the gain setting input terminal VG1 as the base potential,
It outputs a collector current logarithmically expanded with a gain determined by the potential difference. The collector current of the transistor Q12 is inverted by the current mirror circuit composed of the transistors Q13 and Q14 to charge the capacitor C11. The voltage charged in the capacitor C11 is output to the integrated voltage output terminal V01 via the follower amplifier A12. The FET Q15 receives the integration control signal from the input terminal ITG and discharges the capacitor C11. In addition,
These operations are the same for the other four photometric circuits that output V02 to V05.

On the other hand, the collector currents of the transistors Q11 to Q51 are added to charge the capacitor C1. The voltage charged in C1 is compared with the reference voltage E2 by the comparator CP1 and when the relationship is inverted, CP
The output of 1 is inverted from low level to high level, and the output terminal STOP changes from high level to low level. F
The ETQ1 receives the integration control signal from the input terminal ITG and discharges the capacitor C1.

The microcomputer 12 outputs D / from the 8-bit output port PO (8) via the data bus 41.
While outputting data to the A converters 21 to 25, each D / A converter 21 to 25 is set to an independent voltage by a selection signal output from the five terminals of the output ports PO7 to POB.
The output voltages of the D / A converters 21 to 25 are photometric /
The gain setting input terminals VG1 to VG5 of the light control circuit 11 are input. The five integrated voltage output terminals VO1 to VO5 of the photometry / dimming circuit 11 are respectively connected to the microcomputer 1
Two A / D conversion input terminals AD1 to AD5 are connected.
The output port PO1 is connected to the integration control signal input terminal ITG.

Switches 35 and 36 are mechanical switches that operate in the drive sequence of the camera 81, 35 is a mirror-up switch that is turned on when the mirror-up is completed, and 36 is a synchro switch that is turned on when the shutter is fully opened. . Further, the switch 37 is a release start switch which is turned on when the photographer presses the shutter release button, and the switch 38 is a film presence / absence switch for mechanically detecting whether or not a film is loaded in the camera. The signals of these switches 35-38 are
They are connected to the input ports PI1 to PI4 with pull-up resistors of the microcomputer 12, respectively.

The magnets 31 and 32 are magnets for holding the shutter front curtain and the rear curtain, respectively, and are connected to the output ports PO5 and PO6 of the microcomputer 12 through the interfaces 33 and 34, respectively. It is driven and controlled by the computer 12. The light emitting unit 51 is built in the camera 81, and its light emission is controlled by the light emission control circuit 52. The light emission control circuit 52 has a booster circuit (not shown), a main capacitor, a light emission control IGBT, and the like, and starts light emission of the light emitting unit 51 in accordance with a light emission start signal output from the output port PO3 of the microcomputer 12 to the input terminal SX. Then, the light emission of the light emitting unit 51 is stopped in accordance with the light emission stop signal output from the AND gate 13 to the input terminal SSTP. The AND gate 13 emits a light emission stop signal when a high level signal is output from the STOP terminal of the photometry / dimming circuit 11 and a high level signal is output from the output port PO2 of the microcomputer 12. It is supplied to the control circuit 52.

FIGS. 7 and 8 are timing charts showing the operation of each part of the circuits shown in FIGS. 5 and 6, FIG. 7 showing the operation when the film is loaded, and FIG. 8 showing the operation when the film is not loaded. FIG. 9 is a flowchart showing a release routine executed by the microcomputer 12. The operation of the embodiment will be described with reference to these drawings. When the shutter is released and the switch 37 is turned on (point a in FIGS. 7 and 8), the microcomputer 12 of the camera 81 starts execution of the release routine shown in FIG. First, step S1
Then, at the same time when both the front and rear curtain magnets 31 and 32 are energized, the mirror up is started by a driving device (not shown) in step S2 (point b in FIGS. 7 and 8). Step S3
Then, it is determined whether or not the switch 35 is on, that is, whether or not the mirror-up is completed, and when the mirror-up is completed (point c in FIGS. 7 and 8), the process proceeds to step S4, and the switch 38
Is ON, that is, whether or not the film 86 is loaded is determined. If the film 86 is loaded, the process proceeds to step S11 to detect the field reflection light distribution information by the preliminary light emission, but if the film 86 is not loaded, the process proceeds to step S21 and the preliminary light emission sequence is not performed.

First, the operation when the film is loaded will be described.
In step S11, D / A conversion is executed to apply the same predetermined voltage to all the five gain setting voltage input terminals VG1 to VG5 of the photometry / dimming circuit 11 (d in FIG. 7).
point). In a succeeding step S12, a low level integration start signal is output from the output port PO1 to the ITG terminal of the photometry / dimming circuit 11, and a low level light emission start signal is output from the output port PO3 to the terminal SX of the light emission control circuit 52. (Point e in FIG. 7). As a result, the light emitting unit 51 starts preliminary light emission, and the light emission amount increases as shown in e to f of FIG. Each of the light receiving parts PD11 to PD of the photometry / dimming circuit 11
51 receives the reflected light from the object scene and outputs a photocurrent proportional to its brightness.

The circuit operation thereafter will be described for the first channel associated with the light receiving section PD11.
The photocurrent generated in 1 is converted into a logarithmically compressed voltage output by the OP amplifier A11 and the feedback diode D11,
With this potential as the emitter potential, the gain setting voltage input V
Transistors Q11 and Q whose base potential is the potential of G1
It is converted again by 12 into a logarithmically expanded current output. That is, the collector currents of the transistors Q11 and Q12 are amplified by the gain determined by the potential of VG1 while maintaining the proportional relationship with the photocurrent, and the output currents similar to the light emission waveforms of the light emitting unit 51 shown in e to f of FIG. The waveform is shown. The collector current of the transistor Q12 is
It is converted into a source current of the same value by the current mirror circuit composed of 3, Q14, and this current charges the capacitor C11 which is released from the short-circuited state due to the fall of the ITG signal. The charging voltage of the capacitor C11 is converted into a low impedance voltage output by the buffer amplifier A12 and output from the VO1 output terminal. This output voltage rises like the waveform of VO1 shown in e to f of FIG. This is obtained by integrating a photocurrent amplified by a predetermined gain and expressing it in the form of a voltage based on GND.

For the second to fifth channels, the circuit operation itself is the same except that the amount of reflected light in the field changes independently. Transistors Q11-Q51 are VG1-VG
Since the same voltage is applied to 5 in advance to make the gain constant, a current obtained by amplifying the photocurrent with the same gain is output, and these are connected in parallel to amplify the total photocurrent of each channel to the capacitor C1. The current is charged. The terminal voltage of the capacitor C1 changes like the waveform of the C1 integrated voltage shown in FIG. 7, and this voltage changes to the reference voltage E2.
When it falls below the level, the comparator CP1 inverts the output and the terminal STOP changes from the high level to the low level, and this signal is supplied to the SSTP terminal of the light emission control circuit 52 via the AND gate 13 (point f in FIG. 7). ). As a result, the light emitting unit 51 stops emitting light, and thus each light receiving unit PD1
1-PD51 photocurrent also disappears, integration capacitor C
Charging to 11 to C51 is stopped, and output terminal VO1
The voltage of VO5 is constant.

In step S13 of FIG. 9, in order to secure the time for the photometry / dimming circuit 11 to perform the above-mentioned operation,
Waiting for a time of 1 ms is expected in anticipation of the maximum time until the preliminary light emission dimming operation is completed. In step S14, the integrated voltage of the preliminary light emission of VO1 to VO5 corresponding to each of the divided regions of the object scene is set to the A / D of the microcomputer 12.
A / D conversion is performed by the converter, and in a succeeding step S15, the integrated voltage by the preliminary light emission is processed by a predetermined multi-pattern calculation algorithm, and the degree of weighting for the divided area at the time of main light emission for photographing is determined. This multi-pattern operation algorithm is, for example, the above-mentioned Japanese Patent Laid-Open No. 3-68
However, the description thereof is omitted because it is not directly related to the present invention. When the multi-pattern calculation is completed,
In step S16, the output port PO1 is returned to the high level (point g in FIG. 7), and the integration capacitors C1 and C11 to C51 in the photometry / dimming circuit 11 are discharged to prepare for the next main light emission. In step S17, 5-channel D / A conversion is executed in order to apply the gain setting voltage of each channel according to the degree of weighting to each divided area obtained in the above step and the film sensitivity to the VG1 to VG5 terminals ( (Point h in FIG. 7). As a result, it is set so that a large current amplified with a high amplification factor is integrated with respect to a divided region having a high weighting. Thus, the series of preliminary light emission sequences is completed.

When it is determined in step S4 that the film is not loaded, or when the above-described preliminary light emission sequence when the film is loaded is completed, the common step S
21, the shutter control is performed. In step S21, the front curtain magnet 31 is de-energized to start the actual shutter release operation (i in FIGS. 7 and 8).
Point), start running the first curtain. In step S22, it is determined whether or not the switch 36 is turned on, that is, whether or not the shutter is fully opened, and when fully opened (point j in FIGS. 7 and 8), the process proceeds to step S23, where the output port PO1 is lowered to the low level. The start of main light emission is instructed and the integration operation of the photometry / dimming circuit 11 is started. The light emitting section 51 raises the light emission like the light emission waveforms of FIGS.

In step S24, it is determined whether or not the film 86 is loaded by the switch 38. If the film 86 is loaded, the process proceeds to step S27.
If the film 86 is not loaded, the process proceeds to step S25. 30 μs in step S25 when no film is loaded
After waiting for a time, the process proceeds to step S26, and the output port PO2 is lowered to the low level. Output port PO2
The signal output from is supplied to the AND gate 13,
The output of the ND gate 13 lowers the SSTP input of the light emission control circuit 52 to a low level regardless of the function of the photometry / dimming circuit 11, so that the flash light of the light emitting unit 51 when the film is not loaded is small (for example, about GN2). / ISO100). This operation corresponds to the light emission control shown at points j to k in FIG. 8, and the light emission is forcibly ended within a short time of 30 μs from the start of light emission of the light emitting unit 51.

On the other hand, when the film is loaded, the output port PO
Since 2 remains at the high level, the dimming operation by the photometry / dimming circuit 11 is performed as shown by the waveforms at points j to k in FIG. In the photometry / dimming circuit 11, the total sum of the extension currents to which the weights of the transistors Q11 to Q51 are added charges the integration capacitor C1. When this voltage falls below the predetermined reference voltage E2, the STOP terminal changes from the high level to the low level, and the SSTP input of the light emission control circuit 52 falls to the low level via the AND gate 13, so that the light emitting section 51 stops the light emission. (K point in FIG. 7). In both cases of film loading and non-loading, the exposure using the light emitting unit 51 as a light source ends at this point.

In step S27, the time after the deenergization of the front curtain magnet 31 is counted, and the energization of the rear curtain magnet 32 is released when the shutter time set in step S28 has elapsed (FIG. 7, FIG. 7). 8 point 1). In step S29, both terminals of the output ports PO1 and PO2 are returned to the high level to prepare for the release operation of the next frame. Thereafter, when shutter charging and mirror down are performed by a mechanism unit (not shown), the switches 35 and 36 related to each sequence at the points m and n in FIGS. 7 and 8 return to the original off state. This is the end of the shutter release operation.

In this way, when the loading of the film is detected, the exposure of the object to the film at the time of exposure is performed based on the result of detecting the reflected light distribution information of the field due to the preliminary light emission of the flash device before the exposure. If the non-loading of the film is detected by controlling the amount of main light emission so that the amount is appropriate,
Instead of pre-flashing, the flash unit is made to emit light for a short time to control the light emission amount to a small light amount that is unrelated to the proper exposure amount of the film. Battery consumption during loading can be suppressed.

Although the flash device is incorporated in the camera in the above-described embodiment, the present invention can be applied to a camera provided with a hot shoe or the like to which an external flash device can be attached. Can be obtained.

In the configuration of the above embodiment, the photometry / dimming circuit 11 serves as dimming control means, and the microcomputer 12
Is a switch 38 for the light emission amount control means and the control switching means.
Respectively constitute the film detecting means.

[0030]

As described above, according to the present invention, when the loading of the film is detected, the light emission amount of the flash device is controlled so that the exposure amount of the object to the film becomes appropriate. When non-loading is detected, the amount of light emitted from the flash device is controlled to a small amount of light that is irrelevant to the proper exposure amount of the film, so it is possible to check the light emission operation of the flash device while the battery is not loaded. The consumption of can be suppressed. Further, since the preliminary light emission is not performed when the loading of the film is not detected, it is possible to suppress the wasteful consumption of the battery.

[Brief description of drawings]

FIG. 1 is a complaint correspondence diagram.

FIG. 2 is a sectional view of the camera of the embodiment.

FIG. 3 is a diagram showing a configuration of a photoelectric converter and a condenser lens.

4 is an opening area of the film surface viewed from the direction A in FIG. 2;
The figure which shows the positional relationship of a photoelectric converter and a condensing lens.

FIG. 5 is a block diagram showing a configuration of an example.

FIG. 6 is a circuit diagram showing details of a photometry / dimming circuit.

FIG. 7 is a time chart showing a photometry / dimming operation when a film is loaded.

FIG. 8 is a time chart showing a photometry / dimming operation when a film is not loaded.

FIG. 9 is a flowchart showing a release routine of the microcomputer.

[Explanation of symbols]

11 Photometry / dimming circuit 12 Microcomputer 13 AND gate 21-25 D / A converter 31 Front curtain magnet 32 Rear curtain magnet 33, 34 Interface 35-38 Switch 41 D / A data bus 51 Light emitting part 52 Light emission control circuit 81 Camera 82 Photographing lens 83 Movable mirrors 84a, 84b Inner rail 85 Pressure plate 86 Film 87 Front curtain 88 Back cover 91 Photoelectric converter 92 Condensing lens 92a to 92c Lens part 93 Opening area 93a to 93e area 100, 100A Flash device 101 Light control device 101 Control means 102, 102A Light emission amount control means 103 Film detection means 104 Control switching means PD11 to PD51 Light receiving parts D11 to D51 Diodes A11 to A51, A12 to A52 Operational amplifiers Q11 to Q51, Q12 to Q52, Q13 to Q 53, Q
14 to Q54 Transistor Q1, Q15 to Q55 FET C1, C11 to C51 Capacitor G2 Inverter E1, E2 Reference voltage source CP1 Comparator

Claims (4)

[Claims] 1. A camera provided with a dimming control means for controlling a light emission amount of a flash device so that an exposure amount of a subject to a film becomes appropriate, wherein the flash light has a predetermined small light amount irrelevant to the appropriate exposure amount. A light emission amount control means for controlling the light emission amount of the apparatus, a film detection means for detecting the loading and non-loading of the film, and when the film loading is detected by the film detection means, the dimming control means is operated, A camera comprising: a control switching unit that operates the light emission amount control unit when non-loading of a film is detected. 2. The camera according to claim 1, wherein the light emission amount control means causes the flash device to emit light for a predetermined short time. 3. The camera according to claim 1, wherein the flash device is built in the camera and is powered from a battery of the camera. 4. The loading of film is detected in a camera for controlling the emission amount of main light emission at the time of exposure based on the result of detection of reflected light distribution information of the field due to preliminary light emission of the flash device before exposure. A camera comprising film detection means, wherein the preliminary light emission is not performed when the film loading is not detected by the film detection means.