JPH0423247B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides an exposure calculation circuit that can be applied to an automatic exposure camera that is a camera with interchangeable lenses and can set both shutter priority and aperture priority. In other words, it relates to an exposure calculation circuit for a camera that uses an interchangeable lens that allows the aperture value of the lens to be controlled from the camera body side and a conventional lens.

(Prior Art) Conventional interchangeable lenses cannot automatically adjust the aperture from the camera body side.

(Problem to be solved by the invention) A newly developed lens (NEW lens) can control the aperture based on the result calculated on the camera body side, and the information that the lens is attached can be sent to the camera body side. I can tell you.

Even if the camera is equipped with a function to automatically adjust the aperture from the camera body, it is possible for people who own conventional interchangeable lenses that do not have the ability to automatically adjust the aperture from the camera body to use those conventional lenses. It is desirable to keep it.

The purpose of the present invention is to perform calculations on the premise that the aperture value of the lens is controlled from the camera body side when information that a newly developed lens (NEW lens) is attached to the camera body is input. An object of the present invention is to provide an exposure calculation circuit that performs exposure calculation on the premise that the aperture value of the lens is not controlled from the camera body side when the lens is not attached.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the exposure calculation circuit according to the present invention has the following features: a camera operating mode, a set shutter or aperture value, and a format in which the aperture value can be controlled from the camera body side. Information input means INP for inputting information on whether a lens is attached or not, and brightness information input means BTL for inputting information on subject brightness.
When the information that a lens whose aperture value can be controlled is input from the camera body side is input, exposure data is calculated based on the operation mode information and the brightness information, and the camera When a lens whose aperture value can be controlled from the camera body side is not attached, an arithmetic circuit IM that calculates exposure data on the assumption that the lens aperture value is not controlled from the camera body side, regardless of the operation mode setting. ,OPE,COM,SCNT,
It is composed of CNT.

(Example) The exposure calculation circuit according to the present invention will be described in more detail below with reference to the drawings and the like.

FIG. 1 is a block diagram showing an embodiment of an exposure calculation circuit according to the present invention.

The information input section INP contains mode information MS whether the shooting mode is shutter priority Tp, aperture priority Ap, or manual M, set shutter time T or set aperture A, film sensitivity S, information on the attached lens such as the aperture value F, from aperture to Possible narrowing amount C,
This is an input section into which input signals such as lens type signal New and strobe charging completion signal STB are input.The signals sent from INP in a time-division manner are converted into binary codes by a code conversion section CNV, and then converted into an information storage section. Sent to IM.

The information storage unit IM stores each input in the latch memory using the control signal from the calculation control unit CNT, and stores the stored information.
It is sent to the calculation unit OPE by the control signal of CNT.

The mode decoder MDC is connected to the information storage unit IM.
Tp mode, Mp mode, M mode, strobe mode STB, and BULB from setting time T,
Decode SYNC, NC, LOCK. N.C.
LOCK is a strobe-related operating mode signal.

In the case of NC LOCK, when the strobe charge completion signal is not generated, that is, STB
If (NC LOCK)=1, the release signal from the control input unit CINP is prohibited. Also STB・(NC
If LOCK)=1, it is equivalent to shutter time T=1/90sec along with SYNC.

The photometric unit BTL performs AD conversion on the logarithmically compressed photometric values, and sends the photometric data to the arithmetic unit OPE in response to a control signal from the arithmetic control unit CNT. AD conversion is also controlled by a control signal from the shutter sequence control unit SCNT and an AE lock (fixing of photometric value) signal from the control input unit CINP.

The calculation unit OPE calculates the data from the information storage unit IM, the photometry unit BTL, and the calculation results inside the calculation unit based on the control signal from the calculation control unit CNT, and sends the data to the display unit DSP and the coincidence detection unit COM. .
Also sends the calculation process flag to the calculation control unit CNT.
This is the data of the CNT control signal.

The counter and match detection unit COM is the calculation unit OPE.
A coincidence signal between the calculated aperture data from the diaphragm control pulse Pn count value inputted through the aperture control correction unit APJ and a coincidence signal between the calculation time data from the calculation unit OPE and the time counter are sent to the shutter sequence control unit SCNT. send.

The control input section CINP sends release, shutter charge (film advance), self-timer, and trigger signals to the shutter sequence control section SCNT, and the AE
A lock signal is sent to the photometry unit BTL to hold the photometry value B _TLV , and the display unit DSP and calculation control unit
Also sent to CNT for display and calculation control (STB=
1)).

The release, check, and AE lock (fixing photometric values) signals are input to the power hold section PH and serve as power-on signals for the circuit system. The aperture control pulse Pn is a pulse generated in response to the movement of the aperture drive lever, and serves as an input to the aperture control correction unit APJ.

The power hold unit PH is powered on by the above-mentioned signals from the control input unit CINP and the charging completion signal STB from the external strobe, and is held or turned off by a signal from the shutter sequence control unit SCNT.

The aperture control correction unit APJ sends the aperture control pulse Pn from the aperture input unit CINP to the coincidence detection unit COM in accordance with the coded aperture adjustment input.

The shutter sequence control section SCNT is a control input section.
The release magnet RsMg is activated by the control input from CINP and the signal from the power supply check unit BCH, and a series of shutter sequences such as start of aperture, mirror up, etc. are started, and the aperture is controlled by the coincidence signal from the coincidence detection counter COM. Magnet and shutter control Controls the magnet. Also this
SCNT sends signals to COM, OPE, ONT, BTL, and DSP to inform them of the sequence status and control each part.

The power supply check section BCH checks the circuit voltage and controls the display section DSP and shutter sequence control section.
This becomes the control signal for SCNT.

The display unit DSP displays time, aperture, and exposure warnings using display data from the calculation unit OPE, and uses the mode decoder to display time, aperture, and exposure warnings.
Display the mode using mode data from MDC.
Also, the mode display blinks with the AE lock signal to indicate AE lock.

The signal from the voltage check unit BCH causes the display to blink and turn off, etc., to notify the battery status.

The calculation control unit CNT controls aperture and time calculations based on the mode from the mode decoder MDC and the calculation flag from the calculation unit OPE.

Further, the calculated value is fixed by a signal from the shutter sequence control unit SCNT.

Although the lens type signal New was mentioned earlier in the information input section INP, it is planned that two types of lenses will be used in this embodiment. The lens indicated by the signal New is a lens that has been designed so that the aperture can be automatically controlled using aperture control data, and the amount of movement of the lens aperture pin drive lever and the amount of aperture from the actual aperture are in a predetermined relationship. It is a lens unified to Since lenses other than this lens cannot automatically adjust their apertures using aperture control data, they automatically switch to another arithmetic control method (second mode) and do not automatically adjust their apertures from the body.

Now, in the camera having the arithmetic circuit shown in the block diagram, one of Tp, Ap, and Mp selected by the mode select section of the information input section INP is output.
TV set by operating the setting dial or
Suppose that Av or both are output.

Calculated aperture control data C A lens whose aperture cannot be accurately controlled by _VSE , or in other words, a lens is attached that does not have a certain relationship between the amount of movement of the lens aperture pin drive lever and the amount of aperture from the actual aperture. In this case, the aperture preset value Cvms of the lens is calculated as the set aperture regardless of the set value of Tv or Av.When the signal is 1, the aperture is controlled independently of Tp and Ap. In addition, in strobe mode, the shutter time is set to the synchronization time (for example, 1/
90sec), it is necessary to set the exposure memory AEL (Automatic
Exposure Lock) refers to fixing the exposure by fixing the metering value. ) is not operated, the shutter time is automatically set to 1/90sec, when in AEL, the time is calculated according to the aperture signal from the strobe, and when in manual M, exposure compensation can be performed in strobe mode. Aperture is set with C _VMS and time is set with Tv.

In such a configuration, Tp, Ap, M,
Depending on the signals STB, New, and AEL, the combinations shown in FIG. 12 exist. Arithmetic control section
The input signals are automatically selected by the CNT as shown in the combination shown in FIG. 12, and the shutter time and aperture are controlled. STB is a signal that is automatically set when the strobe is fully charged, and New is a signal that is automatically determined when the lens is attached. The operation mode shown in _{FIG .}
Classified as shown in the figure. In FIG. 13, -A or -A is the limit for obtaining proper exposure in conventional auto shooting, but in this application -
In the case of B, -C, -B, and -C, it becomes a multi-program and the set value is automatically corrected by internal calculation to obtain proper exposure.

There is an APEX value between the time value Tv, aperture value Av, film sensitivity value Sv, subject brightness value Bv and exposure value Ev.
Additive System of Photographic
The conditions for proper exposure are Av+Tv=Ev=Bv+Sv (1). To find the aperture value Av from the set time value Tv, just calculate Av=Bv+Sv−Tv...(2), and to find Tv from the set aperture value (aperture value) Av, Tv=Bv+Sv−Av...( 3), but in TTL open metering, Bv
Even if TTL is constant, the photometry unit BTL varies depending on the aperture F value Fv of the lens used, and it is necessary to transform equations (2) and (3) into equations that are functions of the TTL aperture photometry value BTL. Another object of the present invention is to correct the set value Tv or Av to obtain proper exposure when the calculated value Av or Tv based on the set value Tv or Av is in an uncontrollable area. Fv
Enter and introduce the refinable amount C _VM .

Now, the inputs Tv, Av, Sv, and Fv, the narrowing down amount Cv from open corresponding to Av, and the respective internal operation codes Tvs, Avs, Svs, Fvs, and Cvs are configured as shown in FIG. With the input code shown in Figure 10
Q _1- bit s indicates a code that is set to zero when the film sensitivity is Sv.

Input codes Tv, Av, Sv, Fv, shown in Figure 10,
The relationship between the converted value Cv of Cvm and set value Av and the internal operation codes Tvs, Avs, Svs, Fvs, Cvms, and Cv is given by the following equation.

Tvs＝(120) ₈ −Tv×(10) ₈ ……(4) Avs＝Av×(10) ₈ −4 ……(5) Svs＝(140) ₈ −Sv×(10) ₈ ……(6 ) Fvs＝Fv×(10) ₈ −1 ……(7) Cvms＝Cvm×(10) ₈ Cvs＝Cv×(10) ₈ ……(8) In the above formula, (x) ₈ is expressed in octal It is a value.
For example, (10) ₈ corresponds to decimal 8. Below (x) ₈
x in is expressed in octal.

Also, between Av, Fv, and Cv Av＝Fv＋Cv……(9) In other words, Avs=Fvs+Cvs...(10) There is a relationship between

Figure 11 shows Bv and Ev at film sensitivity S100.
FIG. 3 is an explanatory diagram showing the relationship between Bv and the TTL open photometry value B _TLS when a lens with an open F value of F1.4 is used. Between B _TLS , Bv, and Fvs, there is a

Claims (1)

[Claims] 1 Information input means INP for inputting information such as the camera's operating mode, the set shutter or aperture value, and whether or not a type of lens that allows the aperture value to be controlled from the camera body side is attached, as well as information about the subject brightness. brightness information input means BTL, and when information is input that a lens whose aperture value can be controlled from the camera body side is attached, exposure data is input based on the operation mode information and the brightness information. If a lens whose aperture value can be controlled from the camera body side is not attached, the exposure data will be calculated on the assumption that the aperture value of the lens will not be controlled from the camera body side, regardless of the operation mode setting. Exposure calculation circuit composed of calculation circuits IM, OPE, COM, SCNT, and CNT.