JPS5928625A - Exposure control device for camera - Google Patents

Abstract

PURPOSE:To select easily the exposure meeting the intention for composing a picture, by moving successively a photometric region to the high and low luminance parts on an object and collecting the information on the max. and min. luminance in the photometric region thereby corresponding the average value of the max.- and min. values to the adequate exposure value. CONSTITUTION:If the photographic closes a photometric push button 26 to scan the high and low luminance parts on an object and releases the button 26, the information on the max. value and min. value among the measured values are held in max. and min. value detection circuits 12, 30 and the displays corresponding to the same appear on display devices 66, 90. Subtractors 60, 62, 64 perform the subtraction expressed by (V1-V0), (V2-V0), (V3-V0) where the output level of the slider 58 of an exposure factor circuit 54 is defined as V0, and the output levels of a photometric circuit 10, and the circuits 12, 30 are designated respectively as V1, V2, V3. The device 66 displays the results thereof. The exposing time corresponding to the average of the max.- and min. values is displayed on the display device 90 for exposing time. The photographic changes an exposure factor value by changing the position of the slider 58 according to his intention for composing a picture.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an exposure control device for a camera, which is equipped with a photographing lens and a photometer that performs spot metering of object light that has passed through an x-axis and a v-axis.

Prior Art A photometric device with a relatively narrow acceptance angle is used to measure and collect the luminance at multiple arbitrary locations on the subject, and the outputs from multiple locations are simultaneously displayed on a dot display device with a large number of display elements arranged in a row. The display element is displayed on the screen, and the display element is activated according to the change in the set value of the hand setting exposure factor. A camera that can take pictures taking into account the relationship between the two has been proposed in Japanese Patent Laid-Open No. 55-127542.In this proposed camera, when measuring the brightness IW of a desired location, the subject is The camera is configured so that the camera is aimed so that the photometric area matches the desired location, and then the memory switch is pressed.

Therefore, when collecting brightness jW information from two different locations, the memory switch must be pressed twice. However, when determining a high-brightness area, such as a point or line, it is easy to aim at such a brightness area through the viewfinder and press the memory switch. That's not the point.

Purpose The present invention is to collect specific brightness information such as the highest brightness part and the lowest brightness part by a simple operation even when the area is relatively small so that it can be seen as a part, point, or line. is possible,
Furthermore, based on the obtained information, it is an object of the present invention to provide a camera with improved operability that allows easy selection of exposure levels corresponding to the tE diagram.

Summary: Does the exposure control device of the present invention output a relatively narrow acceptance angle of the subject light that has passed through the photographic/zoom and aperture? A photometer 11'1. detects the maximum value and the minimum value of the output signal of the photometer circuit during a period specified by the photographer's operation. / A minimum value detection circuit, an average value circuit that outputs the i1g uniformity of the maximum value and the minimum value, and a circuit that increases the level of the average value expressed by i'+il by the specified step w. a double-defeat circuit; a difference detection circuit that converts the output of the exposure multiple circuit into Cf and determines the difference between this and the maximum value and the difference between the two; 1. according to the output of the display device that simultaneously displays the output and the output multiplier circuit.・'l'W that controls the output
i-1 day ti11? [Characterized by having 11 parts] When taking a picture, put the maximum value and minimum value collapse circuit into the detection state, for example by pressing the button, and while observing and observing the subject through the finder, move the high brightness part and the low part of the subject to 1tllll. Move the light area and press -C. After that, release the button 1-1 to change the detection state to 1+1? Exclude. With the above operations, information on the maximum and minimum brightness in the photometric head area of the object scanned or directed by the imager has been collected. If the exposure multiplier value of the exposure multiplier circuit is set to x1, then the average value of the sampled maximum and minimum values will be matched to the "appropriate exposure value" and exposure control will be performed.Displayed here Taking into account the display data of the device (for example, provided in the finder) and the characteristics of the film, the exposure multiple value can be changed if necessary to determine the exposure value in accordance with the photographic intention.

Embodiment 1 FIG. 1 is a circuit diagram showing a first embodiment in which the present invention is applied to an aperture-priority, automatic exposure time control type camera. In the figure, a light-receiving angle limiting diaphragm is provided at the imaging position behind the photographing lens (2) and the diaphragm (4), and a light-receiving element (8) for photometry is arranged behind it.

In a rangefinder-type focal plane camera, the light receiving element (8) is located in front of the shutter curtain during photometry and is retracted out of the optical path when the shutter release is performed. It will be done.

In the case of a single-lens reflex camera, the mirror box is arranged at one end of the mirror box to receive subject light via a known photometric optical system. The light-receiving element F(8) receives the subject light that enters toward the relatively narrow 9·iI area at the center of the four darkest image directions. A mark indicating this light receiving range is provided at the center of the viewfinder field of view, as shown in FIG. A photometric circuit (1o) including a light receiving element (8) outputs a signal proportional to the logarithm of the intensity of light incident on the light receiving element (8).

When the maximum value production circuit (12) is closed, for example, a push button type photometry switch (26), the switch element (22)
While in the fence state, the maximum value of the Ryogawa signal given from the photometric circuit (1o) is detected. This detection circuit (1
2) is an operational amplifier (14), (1+i),
, a diode (18), a capacitor (20), and switch elements (22) and (24) are the main components 4111'. Switch element (24) control 4dl 7%, Nj
+ (25) is connected to the reset switch (28), and when this switch is closed, it is passed through and the capacitor (
20)% (461) is discharged.II and the small value detection circuit (
:30) is the opposite of the minimum value detection circuit. Detect.

When the reset switch (28) is closed, the switch element (42) is turned off and the capacitor (38) is charged by the power supply. Here, the photometry switch (26
) can be configured to close when a push button provided at a position different from the shutter button is pressed.

Further, the reset switch (28) can be configured to close when a push button other than the photometry switch is pressed. Furthermore, a lever is provided as an operating member for the photometry switch (26) and the reset switch (28), and when pushed in one direction, the photometry switch (26) is activated, and when pushed in the other direction, the reset switch (28) is activated. It may be closed. Alternatively, the operating member is configured with a push button that is pressed in two steps, and when the first step is pressed, the photometry switch (26) is closed, and when the second step is pressed, the 14-t switch (28) is closed and the reset is performed. It may be done as desired.

However, in this case, the next detection operation is not restarted until −11 after the reset operation and the depression of the press button is released.

system system, the 111 circuit (46) is the photometering switch (
26) is closed and the maximum value detection circuit (12) and minimum value detection circuit (30) enter the detection state, the display device I & (66), which will be described later, is activated and the reset switch (
28) is closed, it outputs a control signal that makes it inactive.

In addition, the system control circuit (A6) prohibits shutter release under the 1-state, and controls necessary for sequence control of other circuits. Generates the l111 signal.

The resistors (48) and (5o) connected between the outputs of the maximum value and minimum value detection circuits (12) and (3o) detect the maximum value and minimum value from their contact point (52). It forms an intermediate circuit that outputs the intermediate value or average value. Furthermore, resistance (48)
(50) are set to mutually equal resistances i4n'+, for example.

'4 output multiplier circuit (5) with human power connected to connection point (52)
4) is connected to the performance amplifier (55), constant current circuit (57), resistor (59) and potentiometer (56) as shown in the figure.
56) is shifted to 1 nid according to the position of sliding -J'-(58). When the slider (58) is set at the position corresponding to the subscript ゝゝ0〃, the voltage of the slider is equal to the human power level, and when the subscript is 11 + ITJ, the voltage of the slider is Y (: The output level is trimmed so that 'j+ increases by one step IS.

The subtraction circuits (6o), (62), and (64), which are connected to the output of the exposure multiplier circuit (54) and one of the manual inputs, set the output level from the slider (58) to vO, and set the output level from the slider (58) to vO, and 10
), the output levels of the maximum value and minimum value detection circuits (12), (3o) are set to be different from each other by Vl, V2 . Va Tortoki (Vt-Vo), (V2-Vo), (V
a-Vo) and outputs the result.

Next, the display device (66) displays each subtraction circuit (60), (6
The outputs of 2) and (64) are displayed simultaneously, and when z<(6g), for example, many liquid crystal display elements are arranged in a row and a specific element in the center is set as the origin. The elements at positions corresponding to each output of the subtraction circuit are brought into a display state.

Each element has an exposure value (1-, V value) in increments of 05 steps.
are arranged to correspond to The signal processing circuit (70) is
The output signals from the subtraction circuits (60), (62), and (64) are sequentially switched and taken in in chronological order, converted into a digital signal, and further code-converted into a signal displayed on the display section. An example of the configuration of this display device is shown in FIG. 2, which will be described later.

Next, the arithmetic circuit (72) converts the film sensitivity and preset aperture information to the output of the exposure multiplier circuit (54), and generates the falling time system r]llI signal determined by these three factors. Calculate. h'p f'W Width Q7
4) inversion input and the button yometer (7) following 4.
6) The slider (78) IJ is set at a position corresponding to the film sensitivity. The slide of the potentiometer (80) which is connected in parallel with the potentiometer (76)
(82) is interlocked with the flQ printing presetting means, and the terminal (84) to the end T - (81"i). The terminal (t=1) is grounded via the concentric helix (88). Slide 1! 11 end (82) is the arithmetic circuit (72)
It serves as an output terminal for the exposure time control device (90) and the exposure time display device (92).

The exposure time control Hayashi 1f (92) uses a known circuit consisting of a logarithmic expansion circuit, a current integration circuit, a comparator, etc., and when the shirt release is performed, the output of the arithmetic circuit (72) corresponds to the output city and pressure number. control the exposure time. Exposure It
;'? The interval display device (9()) includes an analog and digital conversion circuit, and displays the exposure time as a digital value in the segment display section.Instead, a meter may be used to display the exposure time in an analog manner. Good too.

In FIG. 2, a switching circuit (94) sequentially switches the outputs of the subtraction circuits (60), (62), and (64) of FIG. 1 in time series and sends them to an A-o conversion circuit (96). The A-D conversion circuit (96) converts the manually input analog electric juice signal into a digital signal. Launch circuit (98), (10 (1)
, (102) are subtraction circuits (60), (62), respectively.
The digital conversion value corresponding to the output of (64) is converted to A −
1) Latch every time f is exchanged. Decoder (1
04), (106), and (108) are latch circuits (98
), (100), and (102) to convert the contents latched into codes according to the display. The three input terminals of the Ok gate (106-i) (i=1 to 25) are the three signal output terminals of the decoders (104), (106), and (]o8) at the same level. The display device (108) has liquid crystal display elements arranged in another row, and the output of 01 (gate (IOfi-i) is
The display element (IHI-i) is driven to the display state at 1 o'clock when the city pressure is 1/l. Center display, element (++o-1:D
Corresponding to the origin, for example, the difference between the two human powers of the subtraction circuit (00) (V+-Vo) kaOo) 14 combined Nico (7) display element 'J'-(I I O-J 3) is driven Is displayed.

V+ -Vo) In the case of Q, the display element (++o-D
~(no-12) Noi gap or mari vl-vO〈
In the case of , the child (IHI-14) to (+1O-25) is displayed.
Either one! ;ノ4IIIIII is displayed.

Next, the operation of the circuit 1- below will be explained. Power switch (
47) to supply power to the circuit 1. If you change it to I¥,
The system control circuit (46) detects maximum and minimum values.
Temporarily outputs an N low voltage signal that resets the ul path (12), (30). At this point, the photometry circuit (10)
) enters the photometry mode, but the display device (6G), (90)
is in a poor harvest+l1ll state, and nothing is displayed.

Next, observe the subject through the fiber optic, press the metering pushbutton, close the switch (26), and move the optical axis to the part of the potting soil where you perceive high brightness or low brightness. Try.

Next, when the push button (26) is released, the maximum value and minimum value detection circuits (12) and (30)
While 6) is pressed, information on the maximum and minimum values of the photometric values collected is held, and the display device (66),
In (90), a corresponding display appears.

When the exposure multiple value is ×1 (subscript ゛ゝO), the maximum and minimum values are displayed, for example, as shown in Fig. The display element enters the display state.Meanwhile, the exposure time display device (90) displays the maximum and minimum values held by the exposure time display device (90).
The appropriate exposure time will be displayed, and the release will be performed at the displayed exposure time. If the brightness difference between the static value and the minimum value with respect to the origin shown on the display device (66') is larger than the latitude of the film, depending on the drawing intention, it may be necessary to It is a good idea to change the exposure multiple value.

Note that the output Vl of the photometric circuit (10) is constantly controlled by the subtraction circuit (6).
0), the brightness of the -1 part other than the detected high-brightness part and low-distortion part is given as
This can be known in relation to the scheduled i7W departure. still,
In detecting the high-brightness and low-brightness areas of the subject, in addition to detecting the maximum brightness and minimum brightness 1w within the shooting scene,
Of course, it is also possible to use it to detect contrast within a specific range.

It is called ``1t'', and uses a solid-state image sensor etc. once a month to collect the brightness information of each point in the photographic field, and from that, detects 1φ human growth 1 view and gorge small 1v. , these flat I
Are you looking for z1111'l? +III exposure amount t, H+ Ji type has all been proposed. However, with such a 4j system, it is difficult to obtain the contrast effect in the part desired by the photographer. On the other hand, according to the method of the present invention, it is possible to grasp the subject's brightness and t!
You can easily set the exposure amount according to your intention.

In the embodiments described above, an aperture-priority type camera is targeted, but the present invention is not limited thereto, and can also be applied to aperture-priority type and program type cameras.

Effect Generally, in order to determine the exposure amount according to the photographer's intention, the brightness state of the subject must be accurately understood in relation to the characteristics of the film.

With the camera equipped with the exposure control device according to the present invention, it is possible to determine the difference in brightness between two desired parts that are different in brightness and are adjacent to each other, or the difference in brightness between two desired parts that are separated from each other by a distance. Furthermore, it is possible to know the relationship between the brightness of each of these two parts and the brightness of any other part. Moreover, the brightness state of the subject can be accurately grasped with simple operations. Furthermore, since the collected luminance information is displayed in relation to the planned exposure amount, the planned exposure amount can be appropriately determined in accordance with the drawing intention.

In addition, in the display device, when the exposure multiple value is ×1,
Information on the maximum and minimum values collected is displayed symmetrically around the average value, and is displayed asymmetrically in cases other than ×1, so by looking at the display status, the exposure multiple value can be adjusted to You can tell whether it is set to 1 or not. Therefore, a separate bar is set up to display the setting status of the h'g output multiple (j
There's no need to.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of the present invention, Figure 2 is a table of the circuit diagram in Figure 1, and circuit diagram showing the specific configuration of the device 66. The figure is a diagram showing an example of the arrangement of display sections within the finder. 2... Photographing lens, 10... Photometry circuit, 12 Maximum value collapse circuit, 26 Photometry switch, 28... Reset switch, : 30... Minimum value detection circuit, 47... Intermediate value circuit, 54... Exposure multiple circuit, 60, 62.64... Difference detection circuit, 60... Display device, 72... Image factor calculation circuit, 90... Exposure time display circuit, 92... Exposure time display circuit. Applicant Minolta Camera Co., Ltd.

Claims (1)

[Scope of Claims] A photometry circuit that receives an object that has passed through a photographic lens and an aperture at a relatively narrow acceptance angle and outputs a photometry signal according to the intensity of the incident light, and photometry of the photometry circuit during a specified period. a maximum value and minimum value detection circuit that detects the maximum value and minimum value of the signal; an intermediate value circuit that outputs an intermediate value between the two outputs of the maximum value and minimum value detection circuit; 1) Based on the output of the exposure multiplier circuit described above, the output of the maximum value and minimum value detection circuit is a first and second difference detection circuit for detecting a difference; a desoto display device for simultaneously displaying the respective outputs of the first and second exchange outputs; and the ejection multiple circuit. 1. A camera camera Fubide Oki 1llll device, characterized in that it is equipped with a mist release control section that controls mist release according to the output of the camera.