JPS5917543A - Camera photometry distribution control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photometric distribution control system for a camera that allows the photometric range to be adjusted depending on the camera's shooting posture.

In general, if the brightness of a subject is not uniform, for example, if the center part is brighter than the peripheral part, or vice versa, the brightness difference between each part is small. For example, even if the subject is measured on average, it does not mean that there will be a significant amount of photometry error. However, if the brightness of each part of the object is extremely different, accurate photometry cannot be expected using the average photometry method, and in this case, the partial photometry method is preferable.

For this reason, conventionally, the photometry accuracy has been improved by switching between average photometry and partial photometry depending on the subject.

However, when there is a brightness difference between the center and the periphery, there is a high probability that the sky will appear above the photographic screen.

For this reason, if photometry is performed in such a way as to eliminate or reduce the influence from above the photographic field, it is possible to probabilistically obtain preferable photographs without having to switch between average and partial photometry.

However, the problem here is that the upper part of the photographing screen differs depending on the horizontal and vertical photographing postures of the camera. For example, if an attempt is made to obtain a good photograph by removing the influence from the sky when photographing in a horizontal position, it is impossible to obtain a good photograph by eliminating the influence from the sky when photographing in a vertical position.

The present invention has been made in view of the above circumstances, and is provided with a plurality of photometry circuits that measure the brightness of different parts of the screen, and a plurality of switch circuits that are opened and closed depending on the shooting posture of the camera. By being equipped with a processing circuit that reduces or eliminates the influence of the photometering circuit on the exposure calculation, which measures the light of a portion of the plurality of photometering circuits according to the signal output from the circuit, it can be adjusted according to the shooting posture of the camera. The present invention aims to provide a photometric distribution control method for a camera that makes it possible to obtain good photographs by eliminating the influence on photometry of a certain part of the screen.

An embodiment of the present invention will be described below with reference to the drawings.

LN is the photographing lens, QM is the quick return mirror, P
G is the focusing plate, CL is the condenser lens, PR is the pentaprism, EL is the eyepiece lens, BM is the beam splitter, ML is the condensing lens for photometry, SP is the photometry unit, S
T stands for shutter and FM stands for film. And D.E.
is a camera attitude difference detection device.

Figure 2 shows the photometry section SP in Figure 1.
The size corresponds to the screen size, 'PM.

is the photodetector that measures the main subject in the center of the screen, PNl~
PN is a light-receiving element that measures the light of a sub-subject around the screen; the light-receiving element PN measures the upper part of the screen in the illustrated state; the light-receiving element PNS measures the right side of the screen in the illustrated state; the light-receiving element PN;
In the illustrated state, the light-receiving element PN measures the light at the bottom of the screen, and the photodetector PN measures the left side of the screen in the illustrated state. FIG. 3 shows an example of the attitude difference detection device DE shown in FIG. '-PW, are arranged, and each switch PW.

-PW, the contacts are electrically connected by the ball BL in the gap. Any one of the four corners of this gap is located below when photographing in the horizontal or vertical position, and the switch at any one of the four corners located below is turned on by the ball BL. In FIG. 3, when the camera is tilted more than 45 degrees from the horizontal, the camera switches from the horizontal position to the vertical position.

Here, FIG. 4 shows the control circuit of the camera shown in FIG. 1. In the figure, PM, , PN, -PN are the light receiving elements shown in FIG. This is the switch shown in Figure 3.

LM is a photometry circuit for main subject photometry consisting of a light-receiving element PM, an operational amplifier OM, a logarithmic compression accumulative element M, and a level adjustment resistor VM; LN, -LN is a light-receiving element PN;

~PN4, operational amplifier ON, ~ON4, logarithmic compression element 1
)Nl -T)N, , level adjustment resistor VN, ~VN
This is a photometering circuit for background photometry made of insects. h to B are resistors, and these resistors L to R4 and the above-mentioned switch PW
, ~PW4 constitute a switch circuit. Also, the resistance R,N, -RN, , the resistance RN,'~l'tN,'
, analog gate G, ~G6, inverter IN, ~IN
, is a processing circuit for controlling the photometric distribution based on the output of the switch circuit. KM, , RK are operational resistors, OA is an operational amplifier that calculates the output of the photometric circuit LM via the resistor RM, and the output of the photometric circuit LN, ~LN, via the processing circuit, ■FS are the photographing information setting circuit, these photographing information setting circuit IFS, and the operational amplifier OP.

Each output is calculated by the calculation resistor OP to the R11% calculation amplifier OP. MT is a meter that displays calculation results, CK
T is a control circuit that controls the shutter control magnet (Mg) based on the calculation result.

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

When the photographer sets the camera to the horizontal position, the conductive ball BL in the posture difference detection device shown in FIG. 3 is positioned downward as shown in the figure due to gravity, and the switch PW is activated.

The contacts of the analog gate G1 are short-circuited and the analog gate G1 is turned off via the inverter IN.

For this purpose, the output of the photometric circuit LM is applied to the operational amplifier OA' via the resistor RM1, and also to the photometric circuit LN.

The output of is applied to the operational amplifier OA through the resistor RN, and the outputs of the photometric circuits LN, , LN, , LN, are connected to the resistors RN,' and RN, , R,N,' and RN,
, R, N, / and RN, based on the parallel values of the operational amplifier O
Added to A.

The output of the operational amplifier OA is calculated with the output of the photographing information setting circuit IF8 by the operational amplifier OP, and this calculated output is displayed on the meter MT, and is also added to the control circuit CRT and sent to the magnet Mg. Shutter control is performed.

In this way, when shooting in the horizontal position, the photometry circuit LN.

The contribution rate of the light to the photometric calculation is reduced, and the influence of the sky is reduced. Furthermore, when the photographer sets the camera in the vertical position, the conductive pole BL in the attitude difference detection device DE moves to a position where it shorts the contacts of the switch PW4, for example, so that the analog gate G4 is connected via the inverter IN. Turn it off.

For this purpose, the output of the photometric circuit LM is applied to the operational amplifier OA/ via the resistor RM, and also to the photometric circuit LN.

The output of is applied to the operational amplifier OA through the resistor RN, and the outputs of the photometric circuits LN, XLN, ,LN, are connected to the resistors R,N,' and RN, and ,RN,' and RN.
, ,RN,' and RN.

The output of the operational amplifier OA, which is added to the operational amplifier OA based on the parallel values of , is calculated with the output of the photographing information setting circuit IF8 by the operational amplifier OP, and this calculated output is applied to the meter M.
At the same time, the shutter is controlled by a magnet Mg which is added to the control circuit CKT.

In this way, when photographing in a vertical position, the contribution rate of the photometry circuit LN4 to the photometry calculation is reduced, and the influence of the sky is reduced.

Furthermore, when the camera is set to the opposite vertical position, the conductive ball BL in the attitude difference detection device DE moves to the position where it shorts the contacts of the switch PW, so the analog gate G8 is turned off via the inverter IN. Then, the meter MT display and the exposure amount are controlled in the same manner as described above.

Therefore, when photographing in the reverse vertical position, the contribution rate of the photometry circuit LN to the photometry calculation is reduced, and the influence of the sky is reduced.

Although such force shooting postures are rare, when the camera is changed from the normal horizontal shooting position to the reverse horizontal shooting position, and furthermore, when the camera is set to the reverse vertical position, the conductive ball BL in the posture difference detection device DE switches. P.W.

Since the contacts of the inverter are moved to the position where they are shorted,
The analog gate G is turned off via the meter MT display and the exposure amount is controlled in the same manner as described above. Therefore, when photographing in the opposite horizontal position, the contribution rate of the photometry circuit LN- to the photometry calculation is reduced, and the influence of the sky is reduced.

In the above embodiment, resistors R3 to R4 are connected in parallel to analog gates GI to G, and these resistors: F
By removing each parallel circuit connected to t, -R, the effect of the void can be eliminated.

In addition, the attitude difference detection device DE is designed to switch from horizontal to vertical photometry distribution when the camera is tilted more than 45 degrees from the horizontal; however, when the attitude difference detection device DE is made vertically long as shown in Fig. If the camera is tilted by 60° or more (from horizontal), the camera switches from the horizontal position to the vertical position, allowing the photometry distribution to prioritize the horizontal shooting posture.

On the other hand, if the posture difference detection device is made horizontally elongated, a photometry distribution that prioritizes the vertical photographing posture can be obtained.

In the above embodiment, the number of light receiving elements of the photometry section SP is 5.
Although the case where there are six or more light receiving elements has been described, it is possible to have six or more light receiving elements by simply considering the arrangement of the light receiving elements, and it is also possible to have four or less light receiving elements by adding conditions. In the case of four light receiving elements, they are arranged as shown in FIG. In this case, it is assumed that horizontal photographing with the camera reversed is rarely performed, and the photometry circuit LN shown in FIG. In the case of three light receiving elements, they are arranged as shown in FIG. In this case, it is assumed that either horizontal photography with the camera reversed or vertical photography is not performed. If you provide a vertical release button separate from the normal release button, there is a very high probability that the other side of the vertical position will be used.
Photometric circuit LN of FIG.

Assume that there is no LN. In the case of Fig. 7, the photometric circuit LN
, ,LN,, the effect of the output of , LN, is only reduced or eliminated, so the switch P can be activated in response to the operation of the normal position release button and the vertical position release button without using the posture difference detection device.
It is sufficient to selectively operate W1 and PW selectively.

As described above, when the present invention is used, the direction of the sky within the screen can be detected from the output of the attitude difference detection means, so the contribution of the light flux from the direction of the sky to photometry can be eliminated or reduced, and an appropriate photometry distribution can be achieved. It is possible to significantly increase the probability of obtaining a photograph with proper exposure.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a single-lens reflex camera showing an embodiment of the present invention, FIG. 2 is a detailed diagram of the photometry section shown in FIG. 1, and FIG. 3 is a detailed diagram of the attitude difference detection device shown in FIG. 1. , Fig. 4 is a control circuit diagram of the camera shown in Fig. 1, Fig. 5 is a detailed diagram showing another example of the posture difference detection device shown in Fig. 1, and Fig. 6 is a diagram of the photometry section shown in Fig. 1. FIG. 7 is a diagram showing still another example of the photometry section shown in FIG. 1. PM, ... Light-receiving element PN, = P Nm, which measures the main subject at the center of the screen. Light-receiving element LM, which measures the sub-subject at the periphery of the screen,... Light-metering circuit LN for main subject metering. ,~LN
m...Photometering circuit for background photometry pw, -pw,...Switch 1 01-G4...Analog gate RN, ~RN, ,RN,'-RN,'...Resistance applicant Canon Corporation 2

Claims (2)

[Claims] (1) Provide a plurality of circuits that measure the brightness of different parts of the screen, and perform photometric calculations for the photometering circuit that measures the portions of the plurality of photometering circuits according to the signals output from the plurality of switch circuits. A photometric distribution control method for a camera, characterized in that it is equipped with a processing circuit that reduces or eliminates the influence of. (2) A photometric distribution control system for a camera according to claim (1), wherein the switch circuit is opened and closed by a posture difference detection means.