JPH0222929B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera having an exposure mode switching device that performs photometry switching in response to exposure mode switching.

Conventionally, exposure mode switching devices have aperture priority mode,
It is possible to switch between a shutter priority mode, a program mode, etc., and recently there have been an increase in the number of programs such as a shutter priority magic mode, an aperture priority magic mode, etc.

Furthermore, the metering method can be selected from center-weighted metering, average metering, partial metering, and spot metering according to the photographer's preference, which has become very convenient for photographers.

However, while being able to switch modes in this way has become more convenient, the operation has become more complicated for beginners, who often do not know how to use it and end up using it incorrectly.

On the other hand, the present applicant proposed in Japanese Patent Application Laid-Open No. 52-11911 that the photometric sensor itself is switched in response to switching between manual shooting and automatic shooting, thereby substantially changing the photometry area.
It is proposed as No. 113730.

The present invention has been made in view of the above-mentioned embodiments, and in a camera capable of switching between multiple programs in which the combination of aperture value and shutter speed is determined according to brightness, the present invention does not simply switch the photometric sensor; By changing the specific weighting in each of the plurality of divided areas in accordance with the switching and calculating the photometric value, it is possible to obtain the photometric value according to the shooting intention of the selected program.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows the program diagram for each exposure mode of the camera. In Figure 1, the vertical axis is the aperture value (FNO), the horizontal axis is the shutter time (T),
The diagonal axis shows the EV value. is a normal program exposure control line and is called normal mode.
is the open F value of the photographing lens F2, the shutter speed changes along the horizontal axis up to 1/1000 seconds according to the subject brightness, and the aperture value changes at 1/1000 seconds.
At F2, the photograph has a shallow depth of field, which is suitable for model photography, so it is called shallow focus mode. Also, the area where the aperture changes from 1/1000 seconds is suitable for shooting fast-moving subjects and is called stop motion mode. Also, is an aperture priority program with an aperture of F11. In other words, the shutter speed changes at F11, and from the point where it intersects the normal mode line.
In areas where the EV value is large, it becomes normal mode.
In this case, the aperture value is F11, so the image will have a deep depth. This mode is called a pamphlet focus mode. At first, the shutter speed changes with aperture priority at F2, but from the 1/60 point, the aperture value changes with shutter priority, and when it reaches F22, the shutter speed changes and becomes larger. In such a case, when photographing a fast-moving subject, you can take a panning shot, resulting in an elegant photograph. This mode is called panning shot mode.

In the present invention, we have considered what kind of photometry mode is optimal for each of these exposure modes, and the results are as follows.

In normal mode, average metering is suitable for general photography.

In the shallow focus mode or stop motion mode, partial metering is suitable in order to position the main subject in the center of the viewfinder screen and make the periphery of the viewfinder screen inconspicuous.

In the pamphlet focus mode, the entire surface must be in focus uniformly, and the image must have an average exposure over the entire screen without emphasizing any part, so average metering is suitable. ing.

The panning shot mode uses a shooting technique called panning. Therefore, since the camera is generally moved sideways on the screen, it is appropriate to measure the light in a strip across the screen.

FIG. 2 shows the optical configuration of the camera, where 1 is a photographing lens, 2 is a movable mirror, 3 is a focusing plate, 4 is a condenser lens, 5 is a pentaprism, and 6 is an eyepiece lens. Therefore, the light that has passed through the photographic lens 1 is reflected by the mirror 2, passes through the focusing plate 3 and the condenser lens 4, is reflected by the pentaprism 5, and is visually recognized as an image by the IP lens 6. The focusing plate 3 is made of an electrical optical diffuser, for example, a liquid crystal, and is divided into appropriate patterns as shown in FIG. 3, and each division is constructed so that a voltage can be applied separately by an individual electrode. has been done. The concentration is changed in each section by applying a pulse voltage. 7 is a liquid crystal drive circuit, and 8 is a light receiving element. 12 is a condensing lens in front of the light receiving element. For example, in FIG. 3, if the voltage is lowered at the part indicated by a on the focusing plate 3 to increase the transparency, and the voltage is increased to lower the transparency at the other parts, partial photometry will be achieved in which the light-receiving element 8 measures the light at the part a.

Therefore, such partial photometry is used in the shallow focus mode and stop motion mode.

Furthermore, if the entire surface of the focusing plate 3 in FIG. 3 is made uniformly transparent, average photometry will be obtained. Normal mode,
When in panfocus mode, average light metering is used.

Furthermore, by increasing the transparency of d, a, and e of the focusing glass 3 and decreasing the transparency of other parts, band-shaped photometry is obtained, and in the panning shot mode, band-shaped photometry is used. 9 is a control circuit which receives the output of the light receiving element 8 as an input. By making the pattern of the light receiving element 8 similar to the liquid crystal pattern of the photometry section, it is possible to display the photometry range. 10 is a mode switching circuit, and 11 is a mode setting circuit.

FIG. 4 shows the light receiving elements 8 (8a, 8b, 8c, 8
This figure shows a drive circuit for the light receiving element 8 and the liquid crystal focus plate 3 when the patterns in d and 8e) and the shape of the liquid crystal pattern displayed by the photometry section of the focus plate are similar. Pattern shape of light receiving element 8 and liquid crystal focus plate 3
Since the shapes of the display patterns are similar, the photometric area can be displayed with a slight difference in density of the liquid crystal on the focus plate, and the focus plate does not become distorted. Light receiving element 8
(8a to 8e) are divided corresponding to the photometric part patterns (a to e) of the focusing plate 3, and are divided into Ga to Ge
is an analog gate for switching the photodetector, CD is a logarithmic compression diode for logarithmically compressing the photocurrent of the photodetector, and OP ₁ is _a high input impedance operational amplifier for photometry. Photometric information obtained by logarithmically compressing the photocurrent generated by the element 8 is output. This photometric information, information set by the exposure information setting circuit IFS, and exposure level correction information are calculated by the operational amplifier _OP2 via the operational resistors R4 to R9. The output of the operational amplifier _OP2 is applied to a known exposure control circuit CKT to control exposure. Tr1 to Tr3 are switching transistors for inputting exposure level correction information, and are switched in conjunction with exposure mode setting.
KVc and Vc are reference power supplies, and Vcc is the power supply voltage.
SW, SW, and SW are switches (not shown) that are linked to the exposure mode setting member, SW is a switch that is turned on in normal mode and pamphlet focus mode, and SW is a switch that is turned on in shallow focus mode and stop motion mode. Switch,
SW is a switch that is turned on in the panning shot mode, and the light receiving element and liquid crystal pattern are selected via pull-down resistors R1 to R3, OR gates _OR1 to _OR5 , and inverters _IN1 to _IN5 .
The electrodes corresponding to the liquid crystal patterns a to e of the focusing plate 3 are _a1 to _e1 , and the structure is such that when a high voltage is applied to _a1 to _e1 , the incident light is scattered and the transparency is reduced. There is.

Next, the operation of the above configuration will be explained.

When the exposure mode setting member (not shown) is set to normal mode or pamphlet focus mode,
The switch SW is turned on, and the switch SW and switch SW remain off. By turning on the switch SW, the power supply voltage Vcc is applied to the OR gates _OR1 to _OR5 and the transistor Tr1. Therefore, transistor Tr1 is turned on, and each OR gate OR ₁ to OR ₅
The output becomes high level. Each of these or gates
High level signals of OR ₁ to OR ₅ are inverter
Since the high voltage is applied to IN ₁ to IN ₅ , no high voltage is applied to the liquid crystal focusing plate 3, so that the liquid crystal focusing plate 3 is entirely transparent, indicating that full-scale photometry is being performed. At the same time, each or gate OR ₁ to
The high level signal from OR ₅ turns on all analog gates Ga to Ge, and the light receiving elements 8a to 8e measure light over the entire surface. These light receiving elements 8a to 8e
The photometric information resulting from the logarithmic compression of the photocurrent generated by the photocurrent is generated from the output of the operational amplifier _OP1 . Metering information and exposure information setting circuit IFS from this operational amplifier OP ₁
Information set by and exposure level correction resistance
It is operated by operational amplifier OP ₂ via R ₄ , R ₅ , R ₈ , and R ₉ . The output of this operational amplifier OP ₂ is added to the exposure control circuit CKT,
CKT performs exposure control based on the output of operational amplifier _OP2 .

When the exposure mode setting member (not shown) is set to shallow focus mode or stop motion mode, the switch SW is turned on.
SW and switch SW remain off. By turning on this switch SW, the power supply voltage Vcc is connected to OR gate OR1 and transistor Tr3.
added to. Therefore, transistor Tr3
is turned on, and only the output of OR gate OR1 becomes high level. This orgate OR
Since the high level signal of 1 is applied to the inverter IN ₁ , b ₁ , c ₁ , d ₁ , e ₁ of the liquid crystal focusing plate 3
A high voltage is applied to the terminal, and the LCD focusing plate 3
The transparency of b, c, d, and e decreases, and a low voltage is applied only to the a terminal of the liquid crystal focusing plate 3, so that only the a terminal of the liquid crystal focusing plate 3 is transparent, indicating that partial photometry is being performed. At the same time, orgate
The high level signal of OR ₁ is the analog gate Ga
is turned on and photometry is performed using the light receiving element 8a. Photometric information obtained by logarithmically compressing the photocurrent generated by these light receiving elements 8a is generated from the output of the operational amplifier _OP1 . It is calculated by the operational amplifier OP ₂ via the photometric information from the operational amplifier OP ₁ , the information set by the exposure information setting circuit IFS, and the exposure level correction resistors R ₄ , R ₇ , R ₈ , and R ₉ . The output of the operational amplifier _OP2 is applied to the exposure control circuit CKT, and the exposure control circuit CKT performs exposure control based on the output of the operational amplifier _OP2 .

When an exposure mode setting member (not shown) is set to the panning shot mode, the switch SW is turned on, and the switch SW and the switch SW remain off. By turning on this switch SW, the power supply voltage Vcc changes to OR gate OR ₁ ,
It is added to OR ₄ , OR ₅ and transistor Tr2.
Therefore, the transistor Tr2 is turned on, and the outputs of the OR gates _OR1 , _OR4 , and _OR5 become high level. This each or gate OR ₁ ,
The high level signals of OR ₄ and OR ₅ are sent to the inverter IN ₁ ,
Since it can be added to IN ₄ and FN ₅ , LCD focusing plate 3
A high voltage is applied to the b ₁ and c ₁ terminals of the LCD, the transparency of b and c of the liquid crystal focusing plate 3 decreases, and no high voltage is applied to the a ₁ , d ₁ and e ₁ terminals of the liquid crystal focusing plate 3. , a, d, and e of the liquid crystal focusing plate 3 are transparent, indicating that band photometry is being used. at the same time,
The high-level signals from the OR gates _OR1 , _OR4 , and _OR5 turn on the analog gates Ga, Gd, and Ge, and the light-receiving elements 8a, 8d, and 8e measure light in the central strip. The photometric information obtained by logarithmically compressing the photocurrent generated from these photodetectors 8a, 8d, and 8e is sent to the operational amplifier.
Resulting from the output of OP ₁ . The photometric information from the operational amplifier OP ₁ , the information set by the exposure information setting circuit IFS, and the exposure level correction resistors R ₄ , R ₆ ,
It is calculated by operational amplifier OP ₂ via R ₈ and R ₉ .
The output of this operational amplifier OP ₂ is used by the exposure control circuit.
In addition to CKT, an exposure control circuit CKT performs exposure control based on the output of operational amplifier _OP2 .

Furthermore, if the exposure modes are displayed as pictures as in Japanese Patent Application Laid-open No. 57-78033, the multi-mode selection as in the present invention can be easily and clearly understood, resulting in improved operability. Furthermore, when it is possible to manually select each photometry method, it has been made so that only partial photometry can be selected in shallow focus and stop motion modes, and only average metering can be selected in normal and panfocus modes. It is also possible to warn or prohibit selections other than strip metering when in panning shot mode.

As described in detail above, according to the present invention, in a camera capable of switching between multiple programs, the weighting of a specific area of the subject can be changed by changing the multiple photoelectric outputs in accordance with switching of the programs. Since it is possible to obtain a photometric value according to the shooting intention in the selected program, even people who are not good at shooting can take photos without having to take the trouble of thinking about photometry suitable for the selected program.

[Brief explanation of drawings]

FIG. 1 is a program diagram for each exposure mode of the camera according to the present invention, FIG. 2 is an optical configuration diagram of the camera showing an embodiment of the present invention, and FIG.
FIG. 4 is a diagram of the liquid crystal focusing plate shown in the figure, and FIG. 4 is a control circuit diagram of the camera shown in FIG. 3...Liquid crystal focusing plate, 8...Light receiving element, 9...Control circuit, 10...Mode switching circuit, 11...Setting circuit.

Claims (1)

[Scope of Claims] 1. A photometer that measures light by dividing a field into a plurality of regions and generates a plurality of photoelectric outputs corresponding to each region, and a combination of an aperture value and a shutter speed depending on the brightness. an exposure mode setting circuit capable of switching between a plurality of programs to be determined; and a photometric value by changing the weighting of the photoelectric output of a specific area in the photometric means according to the type of program switched by the exposure mode setting circuit. A camera having an exposure mode switching device comprising: a computing means for computing; and an exposure mode switching device.