JPH0423248B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to automatic exposure control and display devices for cameras and measurement devices for photography such as exposure meters, and more specifically, to a measuring device for photographing such as an automatic exposure control and display device of a camera and a light meter. Concerning a possible photographic measuring device.

2. Description of the Related Art Conventionally, cameras are known in which film sensitivity information is electrically stored.

Problems to be Solved by the Invention However, once the power is turned off in such a camera, the stored contents of the electrical storage means are also erased, so when the power is turned on again, predetermined film sensitivity information must be preset. There is a need.

If the film sensitivity information display is also used as the shutter speed display to simplify the display configuration, the shutter speed, which changes frequently, is often displayed, so the film sensitivity There is a possibility that a photograph will be taken without knowing that the sensitivity of the film differs from the sensitivity of the film actually used for photographing, resulting in an improperly exposed photograph.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a measuring device for photography that can reduce the possibility of such improper exposure and has a simple configuration.

Means for Solving the Problems In order to achieve the above object, the photography measuring device according to the present invention includes a first presettable counter that electrically stores film sensitivity information, and a first presettable counter that electrically stores film sensitivity information. A second presettable counter electrically stores photographing information, a manual operation switch for specifying whether to change film sensitivity information or photographing information other than film sensitivity information, and a presettable counter. signal output means for outputting an information content change signal for changing the stored information content; film sensitivity information stored in the first presettable counter;
display means for selectively displaying shooting information other than the film sensitivity information stored in the presettable counter of the camera; a switching means for switching between a first state and a second state; a first gate that enables an information content change signal to be input to the first presettable counter in the first state; a second gate that allows an information content change signal to be input to a second presettable counter; and a second gate that outputs film sensitivity information output from the first presettable counter to a display means only in the first state. The present invention is characterized in that it has a third gate and a fourth gate that outputs the film sensitivity information output from the second presettable counter to the display means only in the second state.

(Function) Therefore, according to the present invention, when the power is turned on, the first
Predetermined film sensitivity information is preset in the presettable counter, and the film sensitivity information is displayed on the display means. Thereafter, by operating the manual operation switch, the information of the presettable counter that can be changed by the information content change signal output from the signal output means is displayed on the display means.

Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention. 1 is a photometric circuit that outputs an analog signal corresponding to B _V as an apex value. Reference numeral 3 denotes an A/D conversion circuit which starts an A/D conversion operation upon receiving a start signal from the timing controller 9 via a terminal 94, and outputs an end signal to a terminal 92 when the A/D conversion operation is completed. 5 is a latch circuit, terminal 92
The digital data corresponding to B _V from the A-D conversion circuit is latched by the A-D conversion end signal from the A-D conversion circuit.
SS is a switch that is closed when the metering button is pressed down, US is a switch that is closed in conjunction with the up button that is manually pressed down when increasing the set value, and DS is a down switch that is manually pressed down when decreasing the set value. ATS is a switch that is closed in conjunction with a button that is pressed when switching between changing the film sensitivity setting value and changing the exposure time setting value.

11 is a switching circuit which alternately sets terminals 90 and 40 to "high" every time the switch ATS is closed.
Make it. 13 is a discrimination circuit which discriminates whether the switch US or DS is closed, and outputs one pulse from the terminal 44 when the switch US is closed;
When the switch DS is closed, one pulse is output from the terminal 46, a signal to start displaying the set value is output from the terminal 42, and a signal for starting AD conversion or calculation is output from the terminal 88. . 15 is the terminal 4 when the terminal 90 of the switching circuit 11 is "high"
A film sensitivity setting circuit 17 counts pulses from terminals 44 and 46 and outputs the counting results to data terminals 52 and 53, and 17 counts pulses from terminals 44 and 46 when terminal 40 of switching circuit 11 is "high". , an exposure time setting circuit that outputs the counting results to data terminals 54 and 55. 19 and 21 are display decoders; 19 converts data from the data terminal 52 into data for displaying film sensitivity; when all outputs of the data terminal 52 are "low", all data terminals 56 are "low"; Become. Further, the display decoder 21 converts the data from the data terminal 54 into data for displaying exposure time, and the display decoder 19
Similarly, all outputs of data terminal 54 are “low”
When , all outputs of data terminal 58 are “low”
becomes. OG ₀ is an OR gate that is a combination of a plurality of OR circuits, and data from the decoder 19 or 21 is output from the data terminal 60 . 7 is an arithmetic circuit which receives a start signal from a terminal 96 of the timing controller 9 and receives data from data terminals 50, 53, 55.
The data corresponding to B _V , S _V , _and TV are taken in and the calculation is performed as B _V + S _V − T _V = A _V to calculate the aperture value for proper exposure. Output a signal.

Reference numeral 25 denotes an aperture value display device which takes in calculation data from the arithmetic circuit in response to an end signal from a terminal 48 and displays an aperture value based on this data. 27 is a display device that indicates that the exposure time can be changed when terminal 40 is “high”; 29 is terminal 90;
This is a display device that indicates that the film sensitivity can be changed when is "high". A display device 31 displays the set exposure time or film sensitivity. Note that the diagonal lines added to the signal lines indicate digital data of a plurality of bits.

Next, the operation of the configuration shown in FIG. 1 will be explained.
When the power switch (not shown) is turned on, 15,1
7 is set to an initial value (for example, data corresponding to a shutter speed of 1/125 seconds on ASA100). Also, at this time, the terminal 90 at 11 is set to "high", and the initial value of the film sensitivity at 15 is 19, which is displayed as 31 via OG ₀ .
Note that since the terminal 40 is "low", the initial value of the shutter speed is not output from the terminal 17. Also,
The fact that the terminal 90 is "high" is also transmitted to the terminal 9, and as a result, the A/D conversion of the photometric value is not performed, and therefore the calculation and display of the aperture value by 25 are not performed. Therefore, in this state, the pair of display devices 25, 3
The film sensitivity is displayed only in 31 out of 1. With this, the film sensitivity value set in step 15 can be confirmed. Also, since the terminal 90 is "high", pulses can be input through the terminals 44 and 46, thereby making it possible to change the film sensitivity. That is, U.S.
Each time 13 is manually closed, a pulse is sent from 13 to 15, and the film sensitivity setting value at 15 is increased by 1/3 stop. Similarly, each time the DS is manually closed, the set value decreases by 1/3 step. Changes in set values can be monitored using 31. Also, at this time, since the terminal 40 is "low", the terminal 4
Even if pulses are sent from 4 and 46, the shutter speed value at 17 is not changed.

After checking the film sensitivity or changing the settings,
When ATS is manually closed once, the output of 11 is inverted, terminal 40 is "high" and terminal 90 is "low".
becomes. As a result, the contents of 15 are no longer sent to 31, but instead the shutter speed value from 17 is sent to 31 via 21, OG ₀ and displayed.
Further, when the US or DS is manually operated, contrary to the above, the contents of 15 do not change, and only the contents of 17 change. This change in shutter speed can be monitored by 31. Note that the terminal 90 is “low”
Therefore, when SS is closed, photometry and A-D
The conversion is enabled and a digital measurement signal is obtained at 5. Then, at 7, a digital calculation value signal corresponding to the aperture value is obtained from this digital measurement value signal, the digital film sensitivity signal output from 15, and the digital shutter speed signal output from 17. Displayed in . As a result, the combination of shutter speed and aperture value is displayed on the pair of display devices 25 and 31. Also, when the shutter speed at 31 is changed by operating the US or DS, the aperture value at 25 will also change accordingly, so the desired combination of shutter speed and aperture value can be selected from among the combinations of shutter speed and aperture value that give the correct exposure. You can ask for it. At this time, since the film sensitivity is not displayed, there is no possibility of misreading the displayed information.

When it becomes necessary to change the film sensitivity,
When the ATS is closed again, the output at 11 is inverted again, terminal 90 becomes "high" and terminal 40 becomes "low", and the film sensitivity is displayed at 31, allowing it to be changed. Further, since the A/D conversion start signal is not output, the display of the aperture value by 25 does not change based on the photometric value. Then, when the film sensitivity is changed, the aperture value is calculated based on the data stored in the latch circuit 5, the changed film sensitivity, and the data from the exposure time setting circuit 17. Displayed by. At this time, the changed film sensitivity is displayed on the display device 31.

Next, each component shown in FIG. 1 will be described in detail, and its operation will be explained in further detail.

FIG. 2 shows a specific example of the switching circuit 11 shown in FIG. When the power switch (not shown) is closed,
A power-on reset signal POR is output from the power-on reset circuit (not shown), and this signal is output from the OR circuit OR ₀ to flip-flop FF _0.
is reset, the terminal 90 becomes "high", and the film sensitivity can be changed. switch
Once ATS is closed, the signal from the pulse generator PG ₀ is output from the AND circuit AN ₄ , the flip-flop FF ₀ is set, and the terminal 40 becomes "high", allowing the exposure time to be changed. .
At this time, the function of the delay circuits DL ₀ and DL ₂ is that the terminal 9
When the output of 0,40 is inverted, the pulse generator
This prevents the output of flip-flop FF ₀ from inverting and then returning to its original state while the pulse from PG ₀ continues. Incidentally, if the flip-flop FF ₀ is a master-slave type and the delay time from input to output is longer than the pulse width from the pulse generator PG ₀ , such delay circuits DL ₀ and DL ₂ are not necessary. switch again
When the ATS is closed, the pulse from the pulse generator _PG0 is output from the AND circuit _AN2 , and the flip-flop is reset so that the film sensitivity can be changed. That is, each time the ATS switch is closed, the state in which the film sensitivity can be changed and the state in which the exposure time can be changed are switched, and further, depending on this state, either the display device 27 or 29 displays the At the same time, the display device 31 displays the set film sensitivity or exposure time value.

FIG. 3 is a specific example of the discrimination circuit shown in FIG. 1.
When the power is turned on, the counters CO ₀ , CO ₂ , and CO ₄ are reset by the power-on reset signal.
Further, D flip-flops FF ₂ and FF ₄ are also reset, and RS flip-flop FF ₆ is set. When flip-flop FF ₆ is set, the gate of AND circuit AN ₁₄ is opened and the counter
A clock pulse is input to CO ₄ . As a result, the time required for outputting the display data corresponding to the fixed data (for example, ASA100) set in the setting device 15 from the OR gate OG ₀ in FIG. 1 is counted, and the counter CO ₄ is Carry terminal CY
When it becomes "high", this signal resets the flip-flop FF ₆ and the counter CO ₄ and outputs a pulse from the pulse generator PG ₆ . This pulse is output from the terminal 42 via the OR circuit OR ₁₀ and the AND circuit AN ₁₆ , and is sent to the display device 31. In the display device 31, for example,
100 is displayed. Note that when the power is turned on, the counter
By resetting CO ₀ and CO ₂ , the NOR circuit
The outputs of NOR ₀ and NOR ₂ may rise to "high" and a pulse may be output from the pulse generator PG ₈ , but the flip-flop FF ₆ is set and the gate of the AND circuit AN ₁₆ is closed. This pulse is not output because the

When the switch US or DS is closed, a pulse is output from the pulse generator PG ₂ or PG ₄ . At the rising edge of this pulse, the Q output of flip-flop FF ₂ or FF ₄ becomes "high", the gate of AND circuit AN ₁₀ or AN ₁₂ is opened, and counter CO ₀ or CO ₂ is changed to AND circuit AN ₆ or AN _8. The time required for the setting value of the setting device 15 or 17 to be changed by the pulse from the OR gate OG 0 and the data corresponding to the changed measurement value to be outputted from the OR gate OG ₀ is counted, and when the counting is finished, The output of the NOR circuit NOR ₀ or NOR ₂ rises to "high", the signal from the pulse generator PG ₈ is output from the terminal 42 via the AND circuit AN ₁₆ , and the display device 31 uses this signal to display the data from the OR gate. View acquired and modified measurements. Furthermore, while the counter CO ₀ or CO ₂ is counting, the gates of the AND circuits AN ₆ and AN ₈ are closed, and the pulses from the pulse generators PG ₂ and PG ₄ are not output from the AND circuits AN ₆ and AN ₈ . . moreover,
When the counter CO ₀ or CO ₂ finishes counting, all outputs become “low” and the NOR circuit NOR ₀ or
When the output of NOR ₂ rises to "high", flip-flop FF ₂ or FF ₄ is reset, the gate of AND circuit AN ₁₀ or AN ₁₂ is closed, and no clock is inputted to counter CO ₀ or CO ₂ thereafter. Further, the rising signal of the output of the NOR circuit NOR ₀ or NOR ₂ to "high" is sent from the terminal 88 to the timing controller 9, and this signal is used to output the calculation start signal or A-D conversion start signal. A detailed explanation will be given later.

FIG. 4 shows a specific circuit example of the setting devices 15 and 17 shown in FIG. When the power is turned on, the resettable up/down counters _CO6 and _CO8 are fixed data output circuits by the power-on reset signal POR.
Parallel data from FD ₀ and FD ₂ are preset,
At this time, since the output terminal 90 of the switching circuit 11 is "high", a display (for example, ASA100) corresponding to the data from the AND gate _AG0 is performed.
Further, set data (data corresponding to ASA100, exposure time 1/125) is outputted from the data terminals 53 and 55 to the arithmetic circuit.

In a normal state, AND circuits AN ₁₈ ,
When the gates of AN ₂₀ or AN ₂₂ and AN ₂₄ are opened, the counter CO ₆ or CO ₈ goes up or down by one by a pulse from the terminal 44 or 46 from the discrimination circuit 13. By increasing or decreasing this amount by 1, the data corresponding to the film sensitivity from the counter CO ₆ changes by, for example, 1/3E _V , and the data corresponding to the exposure time from the counter CO ₈ changes, for example.
The decoders 19 and 21 and the arithmetic circuit 7 are configured to change by 1E _V.

FIG. 5 is a specific circuit diagram of the timing controller 9 shown in FIG. 1. When the terminal 90 is "low" and the terminal 88 is "high", that is, the changeable setting value is the exposure time, a certain period of time has elapsed since the switch US or DS was closed, and the switch SS is closed. When this is the case, the gate of the AND circuit AN ₃₈ is opened, and the A/D conversion start signal can be output from the terminal 94. When the switch SS is closed under the above conditions, a pulse is output from the pulse generator PG ₁₀ in response to a rising signal at the terminal 80, and this is output from the terminal 94 as an A/D conversion start signal. In addition, the photometry switch SS
remains closed and the power is turned on, the second
As is clear from the figure, since the terminal 90 is "high", no A/D conversion start signal is output. Furthermore, when the terminal 90 falls from "high" to "low" with the photometry switch SS closed, that is, when the exposure time is switched to a state where it is possible to change, the pulse from the pulse generator PG ₁₄ is output as a signal for starting AD conversion. Also, with the photometry switch SS closed, switch US or
When a certain period of time elapses after closing DS, the terminal 88 rises to "high", and the pulse from the signal pulse generator _PG16 is outputted as an A/D conversion start signal via the AND circuit _AN28 . Furthermore, when the A-D conversion end signal is input from the terminal 92, if the photometric switch SS is closed, the flip-flop _FF8 is set, the gate of the AND circuit _AN36 is opened, and the counter CO When a clock pulse is input to CO ₁₀ and counts for a certain period of time, all outputs of counter CO ₁₀ become “high”.
Next, this rising signal activates the pulse generator.
A pulse for starting A-D conversion is output from PG ₁₈ , and at the same time, this signal causes flip-flop FF ₈ ,
Counter CD ₁₀ is reset. Note that this certain period of time corresponds to the time required for the A/D converted data to be latched in the latch circuit, for calculation to be performed in the calculation circuit 7, and for display to be performed on the display device 25 for a specified period of time.

The calculation start signal from the terminal 96 is not outputted unless the A/D conversion end signal is inputted once after the power is turned on. That is, the flip
The flip-flop _FF10 is reset when the power is turned on, the gate of the AND circuit _AN42 is closed, and when the A-D conversion end signal is input, the flip-flop _{FF10 is} reset.
is set and the gate of AND circuit _AN42 is opened. The timing at which the calculation start signal is output is that the A-D conversion end signal is first input, and then the A-D conversion signal is output for the time necessary for the operation of the latch circuit 5.
The conversion end signal is output after being delayed by the delay circuit _DL4 . Furthermore, when the film sensitivity is changeable, that is, when the terminal 90 is in the "high" state, when the set value is changed, the terminal 88 becomes "high" and the pulse from the pulse generator PG ₁₆ is output to the AND circuit. This pulse is output from AN ₃₀ as a calculation start signal. Further, even when the photometry switch SS is not closed and the set value is changed, a pulse from the pulse generator PG ₁₆ is output from the AND circuit AN ₃₂ , and this becomes the calculation start signal.

When the terminal 90 becomes "high" because the switches US and DS are closed or the switch ATS is closed during A-D conversion, the terminal 98 becomes "low" and the AND The gate of the circuit _AN0 is closed and the A-D conversion completion signal is no longer input to the timing controller 9 and the latch circuit.

When the photometric switch SS is opened, the flip-flop FF ₈ and the counter CO ₁₀ are reset by a pulse from the pulse generator PG ₁₂ , and the A-D conversion start signal is output until the switch SS is closed again. It will no longer be done.

FIG. 6 is an external view when the present invention is applied to a camera. 67 is a power switch, 68 is a photometry button that closes the switch SS, 61 is a switching button that closes the switch ATS, and 6
2 is the down button that closes the switch DS, 6
3 is an up button that closes the switch US. Reference numeral 64 is a section for displaying the set values that can be changed, and is displayed by the display devices 27 and 29 in FIG. Reference numeral 65 denotes a section for displaying changeable setting values, which is displayed by the display device 31. Reference numeral 66 denotes a portion where the calculated exposure control value is displayed, and is displayed by the display device 25.
69 is a release button that starts the exposure control operation of the camera.

FIG. 7 is an external view when the present invention is applied to a light meter. 77 is a power switch, 76 is a photometry button, 70 is a switching button, 71 is an up button, and 72 is a down button. Reference numeral 74 indicates a portion that displays the set values that can be changed, 73 indicates a portion that displays the values of the set values that can be changed, 75 indicates a portion where the calculated exposure control value is displayed, and 78 indicates a light receiving bulb.

In addition, in this example, the case where the aperture value is calculated by setting the film sensitivity and exposure time has been explained, but the same circuit configuration can also be applied to the case where the film sensitivity and aperture value are set and the exposure time is calculated. Yes, and even set only the film sensitivity,
It is also applicable to a so-called program format in which both the aperture value and the exposure time are calculated by a calculation means and a second calculation means. In this case, the first display means (corresponding to FIG. 1 31) switches between displaying the first calculated value information and the setting value information, and the second display means (corresponding to FIG. 1 25) displays the This is an example in which second calculated value information is displayed.

Further, the present invention is applicable to displaying the number of images that can be taken with the used film or the number of films that have been taken so far and the set exposure control value on a common display device.

Furthermore, the present invention is applicable not only to types that count the number of pulses for setting, but also to those that use a digital code board to make settings, and display the set values using a common display device. It is possible.

Furthermore, in the embodiment of the present invention, one pulse is output when the setting switch is closed once, but it may be changed to one in which a pulse train is output while the setting switch is closed. is easy.

Effects of the Invention As detailed above, the photographic measuring device of the present invention is equipped with a display means for selectively displaying either film sensitivity information or other photographic information, and When the predetermined film sensitivity information is preset by inputting the film, the film sensitivity information is always displayed on the display device, and thereafter only the shooting information that can be changed by operating the manual operation switch is displayed on the display means, so the configuration of the display section is simple. At the same time, it is possible to extremely reduce the possibility that photographing information is not set accurately and photographing is performed with inappropriate exposure.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of this invention.
2 is a specific example of the switching circuit shown in FIG. 1, FIG. 3 is a specific example of the discrimination circuit shown in FIG. 1, FIG. 4 is a specific example of the setting circuit shown in FIG. 1, and FIG. 5 is a specific example of the setting circuit shown in FIG. FIG. 6 is an external view of a camera to which the present invention is applied, and FIG. 7 is an external view of a light meter to which the present invention is applied. CO ₆ ……First presettable counter, CO ₈
...Second presettable counter, ATS...
Manual operation switch, US, DS, PG ₂ , PG ₄ ... Signal output means, 19, 21, OG ₀ , 31 ... Display means, PI, FD ₀ ... Preset means, FF ₀ ... Switching means, AN ₁₈ , AN ₂₀ ... first gate AN ₂₂ ,
AN ₂₄ ... second gate, AG ₀ ... third gate,
AG ₂ ...The fourth gate.

Claims (1)

[Scope of Claims] 1. A first presettable counter that electrically stores film sensitivity information, a second presettable counter that electrically stores shooting information other than film sensitivity information, and film sensitivity information. A manual operation switch that specifies whether to change the camera information or photographing information other than the film sensitivity information, and a signal output that outputs an information content change signal to change the information content stored in the presettable counter. and display means for selectively displaying either the film sensitivity information stored in the first presettable counter or the photographing information other than the film sensitivity information stored in the second presettable counter. and presetting means for presetting predetermined film sensitivity information in a first presettable counter based on a signal related to turning on the power; and a first state based on a signal related to turning on the power;
a switching means for switching between a first state and a second state by operating a manual operation switch; and a first switch that allows an information content change signal to be input to a first presettable counter in the first state.
a second gate that enables input of an information content change signal to the second presettable counter in the second state;
a third gate that outputs the film sensitivity information output from the first presettable counter to the display means only in the first state; and a third gate that outputs the film sensitivity information output from the second presettable counter only in the second state. 1. A measuring device for photography, comprising: a fourth gate for outputting film sensitivity information to a display means. 2. The photographic measuring device according to claim 1, wherein the second presettable counter stores an exposure time signal. 3. The photographic measuring device according to claim 1, wherein the second presettable counter stores information regarding the number of films.