JP2000214511A - Electronic view finder, single lens reflex camera, and camera system constituted of electronic view finder and single lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable always monitoring an image having the same finish as that of an image photographed on a film before photographing, irrespectively of the kinds of cameras. SOLUTION: The electronic view finder 1 is constituted of an image pickup device 2 for picking up an optical image in a finder and a monitor device 3 for displaying the picked up image. A calibration mode is set by a CAL.SET switch 302b, and in the case of setting this mode, the luminance ratio of a film plane to the image pickup surface is calculated by test-exposing an object whose luminance is a standard one, and the ratio is previously stored in a memory. In the case the instruction to execute the trial exposure is given by a TR switch 302d before regular photographing, an exposure control value set by the camera 5 is corrected based on the luminance ratio stored in the memory, then, the exposure control value capable of obtaining the same exposure as that at the regular photographing time is calculated, and the object image picked up based on the control value is displayed on the LCD display part 301 for the monitoring device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film camera in which a subject light image formed on a finder of a single-lens reflex camera is picked up by an image pickup device such as a CCD and the picked-up image (still image) is displayed on a display device. An electronic viewfinder capable of monitoring an image substantially the same as a captured image, a single-lens reflex camera connected to the electronic viewfinder communicably, and an electronic viewfinder and a single-lens reflex camera connected communicably to each other The present invention relates to a camera system.

[0002]

2. Description of the Related Art In a camera using a silver halide film, the finished state of a photographed photograph cannot be seen unless the exposed photographic film is printed on recording paper, so that a photograph not intended by the photographer may be produced. Is inconvenient.

In order to solve such a problem, conventionally, C
Equipped with an image sensor such as a CD (Charge Coupled Device)
An imaging device that captures an optical image of a subject formed in a finder, and an LCD (Li) that displays an image captured by the imaging device.
There has been proposed an electronic viewfinder including a monitor device such as a liquid crystal display (quid crystal display).

For example, Japanese Patent Application Laid-Open No. Hei 5-119369 discloses an electronic viewfinder which is used by attaching an image pickup device to a finder window of a single-lens reflex camera. The exposure amount per unit time on a film surface and the image pickup surface of the image pickup device are disclosed. Monitor the image taken under the same shooting conditions as the photograph taken on the film by calculating the difference from the exposure amount per unit time in, and controlling the exposure with the imaging device taking into account the difference in the exposure amount. An electronic viewfinder that can be displayed on the device is shown.

[0005]

By the way, the electronic viewfinder has a finder function and, before photographing on a film, captures an image of the same subject with an imaging device and displays the captured image (still image) on a monitor device. Accordingly, the camera has a function (hereinafter, this function is referred to as a photographed image monitoring function) that allows the user to confirm the finished state of the photographed photograph in advance. For the captured image monitor function of the electronic viewfinder,
In order for a captured image displayed on the monitor device (hereinafter referred to as a monitor image) to have the same finished state as a photograph taken on a film, a test using an image capturing device performed before the film is taken. It is necessary to make the exposure amount of the image pickup device in the simple exposure (hereinafter, referred to as test exposure) substantially equal to the exposure amount of the film.

However, when the electronic view finder is combined with a single-lens reflex camera, the transmitted light of the photographic lens is directly irradiated on the film surface, whereas the finder optical system is used on the imaging surface of the imaging device. The illuminance on the imaging surface is lower than the illuminance on the film surface by the amount of light transmitted through the finder optical system because the transmitted light from the imaging lens guided to the camera is irradiated. Therefore, even if the test exposure of the imaging device is controlled by the exposure control value set on the camera side, the exposure amount on the imaging surface is different from the exposure amount on the film surface, and a monitor image having the same finished state as the photographed image is obtained. Will not be able to do it.
The same applies when the test exposure is controlled by an exposure control value uniquely set on the imaging device side.

Therefore, regardless of the exposure control value set on the camera side or the exposure control value set on the imaging device side, the difference between the brightness of the imaging surface and the brightness of the film is taken into account regardless of which one is used. It is necessary to correct the exposure control value.

[0008] Japanese Patent Application Laid-Open No. Hei 5-119369 discloses that
Calculate the difference between the exposure amount per unit time on the film surface and the exposure amount per unit time on the imaging surface of the imaging device,
Although it is disclosed that exposure in an imaging device is controlled in consideration of the difference in exposure amount, a specific method of setting an exposure control value in test exposure in consideration of the difference in exposure amount is not disclosed.

The publication also mentions that the brightness of the imaging surface and the brightness of the film differ depending on the type of camera combined with the electronic viewfinder, or even between cameras of the same model due to individual differences. No method is disclosed for correcting the difference between the brightness of the imaging surface and the brightness of the film when the electronic viewfinder is combined with an arbitrary camera. Therefore, it cannot be said that the electronic viewfinder described in the publication can always accurately confirm the same finished state as the photographed photograph on the monitor image regardless of the model of the camera combined with the electronic viewfinder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an electronic viewfinder capable of always confirming exactly the same finished state as a photographed photograph on a monitor image regardless of the type of single-lens reflex camera. An object of the present invention is to provide a single-lens reflex camera combined with the electronic viewfinder and a camera system including the electronic viewfinder and the single-lens reflex camera.

[0011]

SUMMARY OF THE INVENTION The present invention relates to an image pickup means which is detachably attached to a finder window of a single-lens reflex camera and picks up a subject light image guided to the finder window;
Instructing means for instructing imaging of a still image, computing means for calculating an exposure control value of the imaging means when the imaging is instructed by the instructing means, and An image pickup control means for controlling the image pickup by the image pickup means, and a display means for displaying a still image picked up by the image pickup means. In an electronic view finder capable of confirming a finished state of a photograph before the actual photographing by displaying an image on the display means, a photometric means for measuring the luminance of an imaging surface of the imaging means, and a photometry of the photometric means Input means for inputting information regarding the exposure of the single-lens reflex camera to the same subject as the target,
Mode setting means for setting a calibration mode, and in the calibration mode, based on luminance measured by the photometry means for the same subject and information on exposure of the single-lens reflex camera input from the input means. A luminance ratio calculating means for calculating a luminance ratio between the luminance of the film surface and the luminance of the imaging surface of the imaging means; and a storage means for storing the luminance ratio calculated by the luminance ratio calculating means. The image pickup method obtains an exposure amount substantially equal to the film exposure amount based on the information on the exposure of the single-lens reflex camera at the time of the main photographing input from the input unit and the luminance ratio stored in the storage unit. The exposure control value of the means is calculated (claim 1).

According to the above configuration, in the calibration mode, for example, the brightness of the imaging surface of the imaging means is detected for a subject of standard brightness, and in the same mode, the same subject is shot by the single-lens reflex camera. When information regarding exposure such as the calculated exposure control value, film sensitivity, and aperture value is input, the luminance ratio between the film surface and the imaging surface of the imaging unit is determined based on the information on the exposure and the luminance of the imaging surface. It is calculated, and the calculation result is stored in the storage means.

Before the actual photographing on the film, information on the exposure of the single-lens reflex camera to the subject to be photographed (especially, the exposure control value) is input, and then, when an image pickup is instructed (hereinafter, this image pickup is called a test exposure). The exposure ratio is read from the storage means, and an exposure control value that can obtain an exposure amount substantially equal to the exposure amount on the film is calculated based on the luminance ratio and the information on the exposure. The imaging of the imaging means is controlled based on. Then, the captured image is displayed on the display means.

The still image picked up by the image pick-up means is picked up with an exposure amount substantially equal to the exposure amount to the film, so that the display means displays an image having a finished state of the photograph taken in the main shooting. Is done.

Further, according to the present invention, in the electronic viewfinder, the luminance ratio calculating means calculates a luminance ratio when a still image is instructed by the instruction means in a calibration mode ( Claim 2).

According to the above configuration, in the calibration mode, when the imaging operation of the imaging means is instructed, the luminance of the imaging surface is measured, and the luminance ratio is calculated using the photometric result.

According to the present invention, in the electronic viewfinder, the information on the exposure of the single-lens reflex camera includes at least an exposure control value and a film sensitivity, and the calculating means includes an aperture value in the imaging before the actual photographing. And the aperture ratio at the time of actual photographing, ΔAv, and the ratio ΔSv between the film sensitivity and the sensitivity of the imaging means are calculated, and the calculated result is added to the luminance ratio ΔBv between the film surface and the imaging surface. The exposure control value of the image pickup means is calculated by correcting the exposure control value at the time of actual photographing with the value (ΔBv + ΔSv + ΔAv) (claim 3).

According to the above configuration, in the test exposure, the ratio ΔAv between the aperture value in the imaging before the actual photographing and the aperture value in the actual photographing, and the ratio ΔAv between the film sensitivity and the sensitivity of the imaging means.
A correction value (ΔBv + ΔSv + ΔAv) obtained by adding Sv and the luminance ratio ΔBv between the film surface and the imaging surface is calculated,
The exposure control value of the imaging means is calculated by correcting the exposure control value of the single-lens reflex camera at the time of the main photographing with this correction value. For example, the exposure time of the single-lens reflex camera at the time of the main shooting is Tv
Assuming that f (apex value), the exposure time Tvc (apex value) of the imaging means at the time of test exposure is Tvc = Tvf +
(ΔBv + ΔSv + ΔAv).

Further, according to the present invention, in the electronic viewfinder, adjusting means for manually adjusting the exposure control value of the imaging means calculated by the arithmetic means, and the adjusted exposure control value and the storage means are stored in the storage means. Correction means for correcting the exposure control value in the single-lens reflex camera at the time of actual photographing based on the brightness ratio and output means for outputting the exposure control value corrected by the correction means. 4).

According to the above arrangement, after the photographer confirms the image of the test exposure displayed on the display means, manually adjusts the exposure control value at the time of the test exposure and performs the test exposure again, the display means Displays a still image having a finished state after adjustment. Then, when the photographer adjusts the exposure control value so as to obtain a desired finished state, the exposure control in the single-lens reflex camera at the time of the main photographing is performed based on the adjusted exposure control value and the luminance ratio stored in the storage means. The value is corrected, and the correction result is output by, for example, displaying on a display unit.

By controlling the exposure to the film with the corrected exposure control value at the time of the actual photographing, a photographed photograph having a desired finished state can be obtained.

In the electronic viewfinder according to the present invention, the input means and the output means may include an input / output terminal to which the single-lens reflex camera is communicably connected, information relating to the exposure of the single-lens reflex camera, and information after correction. Communication means for communicating with the single-lens reflex camera so as to input and output the exposure control value to and from the single-lens reflex camera by communication (claim 5).

According to the above configuration, the electronic viewfinder can automatically transmit and receive the information on the exposure of the single-lens reflex camera and the corrected exposure control value to and from the single-lens reflex camera.

Further, the present invention relates to a single-lens reflex camera to which the electronic viewfinder according to claim 5 is communicably connected, wherein the single-lens reflex camera is connected to an input / output terminal of the electronic viewfinder and is exposed. Communication between a connection terminal for outputting information and a corrected exposure control value, and the electronic viewfinder for inputting and outputting information on the exposure of the single-lens reflex camera and the corrected exposure control value to and from the electronic viewfinder. And an input / output means comprising a communication means for performing the operation (claim 6).

According to the above configuration, the single-lens reflex camera can automatically transmit and receive the information on the exposure of the single-lens reflex camera and the corrected exposure control value to and from the electronic viewfinder.

According to the present invention, the imaging means of the electronic view finder is detachably attached to the finder window of the single-lens reflex camera, and the input means and the output of the electronic view finder. A camera system is provided wherein the means is communicably connected to the input / output means of the single-lens reflex camera.

According to the above configuration, the information on the exposure of the single-lens reflex camera and the corrected exposure control value are communicated between the single-lens reflex camera and the electronic viewfinder at an appropriate timing by communication. This eliminates the need to input information regarding the exposure of the single-lens reflex camera to the electronic viewfinder and to input the corrected exposure control value to the single-lens reflex camera.

[0028]

FIG. 1 is a perspective view showing the configuration of a first embodiment of an electronic viewfinder according to the present invention. 2 and 3 are a front view and a rear view, respectively, showing a state where the electronic viewfinder is mounted on a single-lens reflex camera. FIG. 4 is a view showing a structure of a mounting part for mounting the electronic viewfinder of the single-lens reflex camera. It is a part perspective view.

The electronic viewfinder 1 is a single-lens reflex camera 5
In addition to functioning as a finder of the camera 5 (hereinafter, abbreviated as camera 5), a still image (hereinafter, referred to as a monitor image) captured under substantially the same exposure conditions as the film exposure conditions prior to shooting is displayed on the LCD display unit 301. It has a function that allows the user to confirm the finish of the photograph before shooting by displaying it. The details of the function for confirming the finished state of the photograph will be described later.

The electronic viewfinder 1 comprises an imaging device 2 and a monitor device 3 which are electrically connected to each other by a cable 4.

The imaging device 2 has a horizontally long cubic shape, and is provided with a lens 201 for forming a light image of a subject in a finder on an imaging surface substantially at the center of the front surface. Rails 203 and 204 having a predetermined thickness for mounting the image pickup device 2 on the eyepiece frame 8 (see FIG. 4) provided in the finder window of the camera 5 are formed on the upper front and right and left peripheral portions. The eyepiece frame 8 is formed with grooves 801 and 802 parallel to both left and right side surfaces thereof, and the rails 203 and 204 formed on the front surface of the image pickup device 2 are fitted into the grooves 801 and 802, respectively, to capture an image. The device 2 is mounted on the finder window (see FIG. 3).

The monitor device 3 has a vertically long cube shape.
A flash 307 is provided at the upper part of the front surface, and a dimming window 31 is provided at an appropriate lower part of the front surface. The light control window 31 is a window for receiving the reflected light of the flash light projected from the flash 307 from the subject in order to control the amount of light emission of the flash 307, and a light control sensor (not shown) is provided behind the light control window 31. Is provided.

Further, a display unit 301 (hereinafter, referred to as an LCD display unit 301) comprising a color liquid crystal display (LCD) for displaying an image picked up by the image pickup device 2 is provided at an upper portion of the back surface, and a plurality of display units are provided below the display unit. (See FIG. 3). The display unit 301 may be configured by an electronic display device such as a plasma display panel or an EL panel other than the LCD.

The operation unit 302 has a power switch 30
2a, CAL. SET switch 302b, MR switch 302c, TR switch 302d, SEL switch 30
2e, up switch 302f, down switch 302
g is provided. Note that the SEL switch 302e and the up / down switches 302f and 302g are used for information related to exposure control on the camera 5 side (exposure control value (shutter speed, aperture value), film sensitivity, open aperture value, and the like. Related information) is manually input to the electronic viewfinder 1.

The monitor device 3 is provided with a switch for manually inputting the exposure-related information so that the monitor device 3 can be used for a model of the camera 5 to which the monitor device 3 cannot be mounted for communication. The electronic viewfinder 1 can input exposure-related information by communication as described later. When the electronic viewfinder 1 is mounted on the camera 5 so that communication is possible, the exposure-related information is automatically transmitted from the camera 5 to the electronic viewfinder 1. It is not necessary to manually input the exposure-related information because it is transmitted in a static manner.

The power switch 302a is a switch for turning on the power of the electronic viewfinder 1. The power switch 302a is composed of a push switch, and is alternately switched between ON (power ON) and OFF (power OFF) each time the switch is pressed. The power display 303 is performed by an LED, and is turned on when the power is turned on.

CAL. The SET switch 302b is a switch for setting a calibration mode.
In the calibration mode, when the electronic viewfinder 1 is mounted on the camera 5 and a camera system capable of monitoring a photographed image on a film before photographing is configured, the brightness of the film surface of the camera 5 in the camera system and the imaging device 2 Luminance ratio ΔBv with the luminance of the imaging surface (apex value)
Is calculated, and the luminance ratio ΔBv is stored in the memory. The operation in the calibration mode will be described later. CAL. The SET switch 302b is composed of a push switch, and is alternately switched between ON (mode setting) and OFF (mode release) each time the switch is pressed.

The brightness ratio ΔBv corresponds to the difference in brightness between the film surface and the imaging surface based on the difference in the optical path when an optical image of the same subject is formed on the film surface and the imaging surface of the imaging device 2. However, as will be described later, information necessary for setting the amount of exposure at the time of capturing the monitor image to make the finished state of the monitor image displayed on the LCD display unit 301 substantially the same as the photographed photograph on the film is used. is there.

In the present embodiment, the electronic viewfinder 1 is mounted on various types of cameras 5, and an optical system for guiding the subject light image to the film surface and an optical system for guiding the subject light image to the imaging surface of the imaging device 2. Since the luminance ratio ΔBv based on the difference from the above varies depending on the model of the camera 5, the monitor device 3 is provided with a calibration mode, and the electronic viewfinder 1 is provided.
When a camera system capable of checking a monitor image is configured by combining the camera system and the camera 5, the brightness ratio ΔBv of the camera system can be individually set. However, the recommended camera system is set in advance,
The luminance ratio ΔBv for the camera 5 applied to the camera system may be calculated in advance and stored as a default value in the memory of the monitor device 3 of the electronic viewfinder 1. By doing so, when the user configures the camera system by combining the recommended model of the camera 5 and the electronic viewfinder 1, the operation of setting the luminance ratio ΔBv in the calibration mode is omitted, and the operability is improved.

An SEL switch 302e is an item selection switch for manually inputting information on the exposure control value (shutter speed Tvf, aperture Avf), open aperture value Avo, and film sensitivity Svf on the camera 5 to the electronic viewfinder 1. Each time the SEL switch 302e is pressed, the items of shutter speed Tvf (second), aperture value Avf (apex value), open aperture value Avo (apex value), and film sensitivity Svf (ISO value) are cyclically changed. The input of a specific numerical value for each item is performed by selecting a desired numerical value from a plurality of numerical values set in advance. The selection of this numerical value is performed using the up switch 302f or the down switch 302g.
For example, the shutter speed Tvf is 1/30 to 1/800
Selectable within the range of 0 [seconds], up switch 3
Each time the 02f is operated, the numerical value increases in the ascending direction (1/30 → 1/60 → 1 /
125 →… 1/4000 → 1/8000 → 1/30), and every time the down switch 302g is operated, the numerical value changes in the descending direction (1/8000).
→ 1/4000 → 1/2000 →… 1/600 → 1/30 → 1/8000).

The selected items and numerical values are displayed on the LCD display unit 3.
01, for example, when the shutter speed Tvf is selected, among the display contents shown in FIG.
"X" (where XXXX is a numerical value) is displayed on the LCD display unit 3.
01. Numeric value "XXX" X is up switch 3
The numerical value displayed on the LCD display unit 301 changes according to the operation of the 02f or the down switch 302g, and becomes the set value.

The aperture value Avf can be selected from a range of F1.2 to F64, and the open aperture value Avo can be selected from a range of F1.2 to F8.
f is a predetermined numerical value within a range of 12 to 6400. Further, when the aperture value Avf is selected, “FXX” (where XX is a numerical value) is displayed on the display 301, and when the aperture value Avo is selected, “Fox. X] (where XX is a numerical value) is displayed, and when the film sensitivity Svf is selected, the display 301 displays “ISO XXXX” (where XXXX is a numerical value).

In the calibration mode, SE
When the L switch 302e is operated, the mode becomes an input mode of exposure-related information on the camera 5, and the SEL switch 302e is operated.
Each time is operated, the input items and set values are displayed on the LCD display unit 3.
01 is displayed. Information of each input item is used to calculate the luminance ratio ΔBv. Also, in a mode in which a moving image captured by the image capturing device 2 is displayed on the LCD display unit 301 of the monitor device 3 (hereinafter, referred to as a finder mode), when the SEL switch 302e is operated, exposure related to the camera 5 side is performed. In the information input mode, the SEL switch 30
Every time 2e is operated, the input items and the set values are displayed on the LCD display unit 301. The information of each input item is an exposure control value (electronic viewfinder) at the time of exposure (hereinafter, this exposure is referred to as test exposure) that is experimentally performed by the imaging device 2 in order to monitor a photographed image on a film before photographing. This is used when setting the exposure control value.

The MR switch 302c is fetched by the imaging device 2 in the test exposure, reads out the monitor image stored in the memory in the monitor device 3 from the memory, and reads the monitor image from the memory.
An operation member for displaying on the display unit 301. In the reproduction of the monitor image, the exposure condition of the film (the correction value ΔGv of the flash emission amount, the shutter speed Tvf, the aperture value Avf, etc.) is also displayed on the LCD display 301. Display processing of the monitor image will be described later.

The CAL. FIG. 6 shows the relationship between the function of each switch from the SET switch 302b to the down switch 302g and the display content on the LCD display unit 301 based on the operation.

In the figure, "N.DSP" indicates the function of each switch in the finder mode and the display contents. "NON DSP &" in "N. DSP"
"IN" is a state in which the exposure-related information cannot be input, and the monitor device 3 uses the electronic viewfinder (EVF).
Is operating only as Also, "CAL.
"MODE" indicates the function of each switch in the calibration mode and the display content thereof.
"E" indicates the function of each switch and the display content in the mode in which the monitor image is displayed on the LCD display unit 301.

Further, in FIG.
T, "MR" and "TR" are CAL. SET
"SEL", "▲" indicates that the switch 302b, the MR switch 302c, and the TR switch 302d are operated.
And "▼" indicate that the SEL switch 302e, the up switch 302f, and the down switch 302g are operated, respectively.

As shown in FIG. 6, in the finder mode, CAL. When the SET switch 302b is pressed,
The calibration mode is set. In the finder mode, when the TR switch 302d is pressed after the exposure-related information of the camera 5 is input, test exposure is performed, and the monitor image captured by the imaging device 2 is displayed on the LCDD display unit 301 of the monitor device 3. Is displayed for a predetermined time. In this test exposure, when the subject has low brightness, the flash 307 is automatically emitted, and the monitor image captured by the flash is displayed on the LCD display unit 301. The monitor image is displayed on the LCD display unit 30 immediately after the test exposure.
1 is displayed on the LCD display 301 by pressing the MR switch 302c thereafter.

Returning to FIG. 1, an attachment portion 304 for attaching the monitor device 3 to the shoe portion 9 of the camera 5 (see FIG. 4) is formed substantially at the center of the bottom surface of the monitor device 3. The shoe portion 9 has a guide groove 901 at the center, and a plurality of contacts 904 arranged at a predetermined pitch in the longitudinal direction on the bottom surface of the guide groove 901. In addition, a shoe groove 902 having an L-shaped cross section is parallel to both sides of the guide groove 901.
903 is drilled. The mounting portion 304 has a terminal block 305a extending in the width direction at the center, and a plurality of connection terminals 306 protrude from an upper surface of the terminal block 305a. Also,
On both sides of the terminal block 305a, rails 305b and 305c are provided, which are formed by projecting projecting pieces having an L-shaped cross section extending in the width direction.

The monitor device 3 includes rails 305b and 305c.
Are fitted to the shoe grooves 902 and 903, respectively, thereby being attached to the camera 5 (see FIGS. 2 and 3). At this time, the terminal block 305a fits into the guide groove 901, and the connection terminal 306 on the monitor device 3 and the contact 90 on the camera 5 side.
1 and the monitor device 3 and the camera 5 are communicably connected.

The ends (rear ends) of both rails 305b and 305c are bent inward to be continuous in a U-shape. When the mounting portion 304 is slid to the shoe portion 9 and mounted, the continuous portion is formed. As a stopper, the monitor device 3 is fixed to a predetermined position of the shoe portion 9 of the camera 5 (a position where the connection terminal 306 on the monitor device 3 and the contact 901 on the camera 5 contact).

The camera 5 comprises a camera body 6 and an interchangeable lens 7. The interchangeable lens 7 is detachably attached to a lens mounting portion 601 provided substantially at the center of the front surface of the camera body 6. A shutter button 602 is provided on the right side when viewed from the back of the upper surface of the camera body 6.
Although not shown, switches are provided at appropriate places on the upper surface of the camera body 6 for inputting various types of information (exposure mode, exposure correction value, film sensitivity, self-timer shooting, continuous shooting, etc.) related to exposure conditions. Have been.

FIG. 7 is a diagram showing a schematic configuration of an optical system of the camera 5 to which the electronic viewfinder 1 is attached.

In the lens barrel of the interchangeable lens 7, a plurality of lens groups 701 are disposed so as to be movable in the optical axis direction.
A diaphragm 702 is built in the inside of the lens. An exposure position of the film F is provided at a position on the inner surface of the back cover of the camera body 6 where the optical axis of the interchangeable lens 7 is input. A main mirror 14, which is a mirror (a mirror that transmits light only at the center position), is provided rotatably upward.

A sub-mirror 15 for totally reflecting the transmitted light downward is attached substantially at the center of the back surface of the main mirror 14,
A light receiving element 16 for measuring the luminance of the film surface is provided at a position below the sub mirror 15 and equivalent to the exposure position of the film F. This light receiving element 16 (hereinafter, referred to as
It is called a photometric sensor 16. ) Is, for example, SPD (Silicon
Photo Diode).

Further, a Fresnel focus plate 13 is disposed above the main mirror 14 at a position equivalent to the film surface, and an object light image formed on the Fresnel focus plate 13 is erected above the main mirror 14. A condenser lens 12 and a pentaprism 11 which are inverted into an image and lead to an eye point of a finder window are arranged in this order. An eyepiece lens 10 for enlarging an erect erect image of the subject light guided by the pentaprism 11 is disposed between the pentaprism 11 and the finder window.

Then, the eyepiece 10 to the main mirror 1
4 constitutes a finder optical system of the camera 1. That is, the subject light image transmitted through the lens group 701 of the interchangeable lens 7 is reflected upward by the main mirror 14 and formed on the focus surface of the Fresnel focus plate 13 as a left-right reversed image. This light image is condensed by the Fresnel lens of the Fresnel focus plate 13 and the condenser lens 12 and guided to the pentaprism 11, inverted by the pentaprism 11 into an erect erect image, and then enlarged by the eyepiece 10 to be enlarged by the viewfinder. The light is emitted to the eye point of the window.

In the image pickup apparatus 2, a lens 201 for forming a subject light image on an image pickup surface, an area sensor 202 for photoelectrically converting the subject light image into an image signal, and the area sensor 202 are provided.
02 is provided with a CCD control unit 203 for controlling the driving of the CCD. The area sensor 202 is composed of, for example, a Bayer type single-plate color CCD area sensor. An area sensor 202 (hereinafter, referred to as a CCD 202) separates a captured image into R (red), G (green), and B (blue) color components and outputs them to the monitor device 3.

In the monitor device 3, an LCD display unit 301,
Xenon tube 309 constituting flash 307, flash circuit 310 for controlling light emission of xenon tube 309
And a control unit 308 for controlling the operation of the monitor device 3.

FIG. 8 is a circuit block diagram of a camera provided with an electronic viewfinder. Also, FIG.
FIG. 3 is a diagram illustrating an example of a specific circuit of the flash circuit 310.

In FIG. 8, blocks A, B, C, and D indicate circuit configurations in the image pickup device 2, the monitor device 3, the camera body 6, and the interchangeable lens 7, respectively. In each block, the same members as those shown in FIGS. 1 to 7 are denoted by the same reference numerals.

In block A, the CCD controller 203
Controls the driving of the CCD 202 and
The image signal (analog signal) captured in step 2 is subjected to predetermined signal processing and output. CCD controller 203
Controls the driving of the CCD 202 based on a timing signal (clock) input from a timing control circuit in the monitor device 3.

In the block B, the flash circuit 3
Reference numeral 10 denotes a circuit for controlling light emission of the xenon tube 309.
A power supply battery E1 is supplied to the flash circuit 310, and driving of the flash circuit 310 is controlled by the CPU 308.

The flash circuit 310 has the circuit configuration shown in FIG. In the figure, the booster circuit 310a is intended to supply to the main capacitor C _M by boosting the power supply voltage E1 to a predetermined charging voltage. The boosting circuit 310a is DC
The DC boost converter is controlled by the CPU 308. Main condenser _CM is xenon tube 3
09 accumulates discharge charges for emitting light.

[0065] Diode D is a rectifying element for preventing the charging current from flowing back to the booster circuit 310a from the main capacitor C _M during charging. Transformer T, resistor R, capacitor C and IGBT (Insulated Gate Bipolar Tra)
The xenon tube 309 emits light and stops the light emission. A light emission start signal (high level signal) and a light emission stop signal (low level signal) are input to the base of the IGBT from the light emission control circuit 310a.

The light emission control circuit 310b controls the light emission amount of the xenon tube 309. Light emission control circuit 3
10b sets the dimming level (that is, the level of the light emission amount) at the time of the main shooting based on the guide number Gv input from the CPU 308 at the time of the exposure to the film (hereinafter, this exposure is referred to as the main shooting). The dimming level is input to an inverting input terminal of a comparator 310d which is a component of the dimming circuit. During the test exposure, the CPU 308
The dimming level at the time of the test exposure is set based on the guide number correction value ΔGv input from the controller, and the dimming level is input to the inverting input terminal of the comparator 310d. Further, the light emission control circuit 310b performs IBG based on the main light emission start signal or the test light emission start signal input from the CPU 308.
By outputting a light emission start signal to T, the xenon tube 30
9, and controls the light emission stop timing by outputting a light emission stop signal to the IGBT based on the light control signal input from the comparator 310d.

The light receiving element Dh corresponds to a dimming sensor provided at a position facing the dimming window 31. The light receiving element Dh receives the reflected light of the flash light from the subject, photoelectrically converts the light into a current, and outputs the current. . The light quantity integration circuit 310c is a circuit that equivalently integrates the amount of received light by integrating the current output from the light receiving element Dh, converts the integrated value into a voltage, and outputs the voltage. This output voltage is input to the non-inverting input terminal of the comparator 310d. The comparator 310d is a circuit that compares the voltage output from the light intensity integration circuit 310c with the dimming level, and outputs a dimming signal for forcibly stopping light emission when the amount of received light reaches a predetermined dimming level. A light control circuit is configured by the light receiving element Dh, the light amount integration circuit 310c, and the comparator 310d.

[0068] In the flash circuit 310 shown in FIG. 9, the charging of the main capacitor C _M is performed by driving the step-up circuit 310a and the IGBT in the off state. When the charging current is output from the boosting circuit 310, the main capacitor _CM is charged by the charging current. In addition, a part of the charging current flows through a series circuit of the capacitor C, the resistor R, and the secondary winding of the transformer T, and the capacitor C is charged to the polarity shown in the drawing, whereby the light emission is enabled.

When a light emission start signal (high level signal) is input from the light emission control circuit 310b to the IGBT, the charge stored in the capacitor C is discharged through the IGBT and the secondary winding of the transformer T, thereby discharging the transformer T. A high voltage of several kV is induced in the primary winding and applied to the trigger terminal of the xenon tube 309. At this time, the xenon tube 309 is IG
Since the discharge path via the BT is configured, the charge accumulated in the main capacitor C _M by the high voltage applied to the trigger terminal is discharged via the xenon tube 309 and IGBT, which flash is emitted by .

The light control operation of the light control circuit is started simultaneously with the light emission of the xenon tube 309 (ie, the integration operation of the light amount integration circuit 310c is started), and the light control signal is sent from the light control circuit to the light emission control circuit 310b. In response to the input, a light emission stop signal is input from the light emission control circuit 310b to the IGBT in response to this, so that the IBGT is turned off (that is, the discharge paths of the xenon tube 309 and the IGBT are cut off). Light emission is forcibly stopped.

Returning to FIG. 8, the A / D conversion circuit 311 converts an image signal input from the imaging device 2 via the cable 4 into a digital signal. The video signal processing circuit 312 performs predetermined signal processing (signal processing such as black correction, white balance, and γ correction) on the image signal. A / D conversion circuit 311 and video signal processing circuit 312
Performs A / D conversion and signal processing of an image signal (a signal received by each pixel of the CCD 202) based on a timing signal input from the timing control circuit 315. The display memory 313 is a memory for temporarily storing digital image signals (hereinafter, referred to as image data) on which signal processing has been performed. The LCD driver 314 is connected to the LCD display unit 301.
This is for controlling the driving of. The LCD driver 314 controls the light emission of each pixel of the LCD display unit 301 based on the image data input from the display memory 313, so that the captured image stored in the display memory 313 can be displayed on the LCD.
It is displayed on the display unit 301.

The timing control circuit 315 includes the CCD 20
2. A / D conversion circuit 311 and video signal processing circuit 312
1 is a circuit for generating a timing signal for controlling the timing of signal processing for the data. The switch circuit 316 is a switch for controlling power supply to the imaging device 2. ON / OFF of the switch circuit 316 is controlled by the control unit 308.
When the switch circuit 316 is turned on,
Power is supplied from the power supply battery E1 in the monitor device 3 to the imaging device 2 via the cable 4.

The control section 308 is a control section for centrally controlling the operation of each circuit block in the monitor device 3. Control unit 30
Reference numeral 8 (hereinafter, referred to as CPU 308) includes a microcomputer. CPU 308 is ROM 308
a and a RAM 308b, and a control program and initial data are stored in the ROM 308a. The above-described default value of the luminance ratio ΔBv is also stored in the ROM 308a. In the RAM 308b, data necessary for the CPU 308 to perform predetermined processing according to the control program (program data and initial data read from the ROM 308a, set by the switch group 317, or communicated from the camera body 6 when possible) (Tvf, Av) related to the exposure control on the camera 5 side
f, Avo, Avf, etc.) are stored.

In the present embodiment, since the monitor device 3 is mounted on the camera body 6 so as to be able to communicate, when data relating to exposure conditions is input from the camera body 6, the data becomes R
Stored in the AM 308b.

The switch group 317 corresponds to a switch group provided on the operation unit 302. Switch group 31
7, the switches S _M , S _CAL , S _MR , S _TR , S _SEL ,
S _UP and S _DOWN are the power switch 3 of the operation unit 302, respectively.
02a, CAL. SET switch 302b, MR switch 302c, TR switch 302d, SET switch 3
02e, up switch 302f, down switch 30
2f. Switch group 317 to CPU 30
8, operation signals of the switches 302a to 302g of the operation unit 302 are input. The connector 17 is connected to the connection terminal 3.
It corresponds to a connecting portion composed of a contact 06 and a contact 904.

In the block C, the control unit 609 controls the photographing operation by centrally controlling the circuits and actuators in the camera 5, and is composed of a microcomputer. The switch group 603 is for inputting an operation signal of an operation member such as a shutter button 601 to a control unit 609 (hereinafter, referred to as a CPU 609). S _M switches in the switch group 603 is a power switch provided on the camera body 6. The S1 switch and the S2 switch are switches for detecting a half-press operation and a full-press operation of the shutter button 601 respectively. The S _+/− switch is a switch that detects an operation of an exposure correction switch (not shown) for correcting the exposure control value Evf. The detection signals of these switches are input to the CPU 609. In addition,
When the operator operates the exposure compensation switch to input a compensation value ΔEvf (apex value) for the proper exposure Evf (apex value) calculated by the CPU 609, the compensation value ΔEvf is stored in the monitor device 3 via the CPU 609. CP
It is input to U308.

The AF control section 604 controls the driving of the lens group 701 in the interchangeable lens 7 to adjust the focus. The aperture control unit 605 controls the driving of the aperture 702 in the interchangeable lens 7 to adjust the aperture value.

The distance measuring section 606 detects data (defocus data) relating to the deviation of the lens group 701 from the in-focus position. The distance measuring unit 606 is controlled by the CPU 609, and when instructed by the CPU 609 to measure distance, calculates defocus data based on a light receiving signal output from a distance measuring sensor (not shown) and outputs the calculation result to the CPU 609. . The CPU 609 drives the lens group 701 via the AF control unit 604 based on the defocus data, and adjusts the focus of the interchangeable lens 7.

The photometer 607 measures the brightness of the subject, more precisely, the brightness of the film surface. Photometry unit 60
The CPU 7 is controlled by the CPU 609, and when the CPU 609 instructs photometry, calculates the brightness of the subject based on the light receiving signal output from the photometry sensor 16 and outputs the calculation result to the CPU 609. The CPU 609 calculates an exposure control value (shutter speed Tvf, aperture Avf) based on the luminance data, and outputs the aperture value through the aperture control unit 605.
02 is driven to adjust the aperture amount of the interchangeable lens 7. Further, the CPU 609 transmits the exposure control value to the CPU 308 of the monitor device 3.

The DX reading section 608 reads information (DX data) relating to the film loaded in the camera. The DX reading unit 608 includes, for example, a plurality of contact points provided at appropriate positions in a film loading chamber. When a DX code is recorded on the surface of the patrone, the DX reading unit 608 loads the patrone into the film loading chamber. The DX code is read by detecting the state of each contact. Note that D
If the X data is recorded optically or magnetically, D
DX data can be automatically read by configuring the X reading unit 608 with corresponding optical or magnetic means.

The lens microcomputer 703 in the block D controls the driving of the interchangeable lens 7.

Next, the function of displaying a monitor image on the electronic viewfinder 1 in the camera system having the above configuration will be described.

First, an exposure condition for displaying a monitor image having substantially the same finishing state as a photographed image of a film on the electronic viewfinder 1 will be described. In addition,
Apex values are used for parameters related to exposure control, such as shutter speed and aperture, unless otherwise indicated. In addition, without performing the exposure operation with the camera 5 (that is, in a state where the film F is shielded from light by the main mirror 14), the still image captured by performing the test exposure only with the imaging device 2 is used as the monitor image of the monitor device 3. It shall be displayed on the LCD display unit 301.

(1) In Case of Steady Light Photographing Assuming that the same subject is photographed by the camera 5 and the image pickup device 2, the proper exposure calculated by the photometry result of the photometry unit 607 in the camera 5 is Evf, and this proper exposure Evf Set the shutter speed to Tvf and the aperture to Av based on
f, the open aperture value of the aperture 702 is Avo. Further, the brightness of the film surface when the aperture 702 is stopped down is Bvf, the brightness of the film surface when the aperture is open is Bvfo, and the sensitivity of the film is Svf. On the other hand, in the imaging device 2, the proper exposure is Evc, and the exposure time (integration time) of the CCD 203 set based on the proper exposure Evc and the aperture Avf.
Is Tvc. Also, the CCD when the aperture 702 is stopped down
The brightness of the imaging surface 203 (hereinafter, referred to as a CCD surface) is Bvc, the brightness of the CCD surface at the time of full aperture is Bvco,
Let the sensitivity of the CCD 203 be Svc.

In FIG. 7, the aperture 702 is set to an aperture value Avf
Assuming that the test exposure of the imaging apparatus 2 is performed in a state where the focus is narrowed down, Evf = Tvf + Avf = Bvf + Svc (1) Evc = Tvc + Avf = Bvc + Svc (2) Therefore, Tvf = Bvc + Svc-Avf (3) Tvc + Bvc = Bvc -Avf ... (4) is established.

Now, ΔBv = Bvc−Bvf, ΔSv = S
vc−Svf, ΔEv = Evc−Evf, and when equation (3) is subtracted from equation (4), Tvc−Tvf = ΔBv + ΔSv = ΔEv, and the exposure time Tvc of the CCD 203 is: Becomes

From the equation (5), if the exposure amount Evf of the film F is equal to the exposure amount Evc of the CCD 203 (ΔEv =
0), since the optical system of the film F and the aperture 702 of the optical system of the CCD 203 are shared, if the CCD 203 is exposed for the exposure time Tvf calculated by the camera 5, the same finishing condition as the photographed image is obtained. Can be obtained. However, usually, the film speed Sv
Since f is arbitrarily selected by the operator, it is different from the sensitivity Svc of the CCD, and the brightness Svc of the CCD surface is smaller than the brightness Svc of the film surface because the light beam passes through the finder optical system. Lower (ie,
Exposure amount Evf of film F and exposure amount Ev of CCD 203
c), the camera 5 is obtained from the expression (6).
Unless the CCD 203 is exposed at the shutter speed Tvc obtained by correcting the exposure time Tvf calculated by (ΔBv + ΔSv), the finished condition of the monitor image cannot be made the same as the finished condition of the photographed image.

In the camera 5, the shutter button 602 is fully depressed and the aperture 7 is set immediately before the exposure operation is performed.
When the aperture amount of 02 is set to the aperture value Avf, the aperture 702 is maintained at the open aperture value Avo when the test exposure is performed by the electronic viewfinder 1, so that
In addition to the above equation (6), the aperture ratio ΔAv (=
It is necessary to add a correction term of Avf-Avo).

That is, the CCD 2 at the open aperture value Avo
Assuming that the exposure time of 03 is Tvco, Tvco = Bvc + Svc-Avo (7). Therefore, when equation (4) is subtracted from equation (7), And the exposure time Tvc of the CCD 203 is as follows: Tvco = Tvf + ΔBv + ΔSv + ΔAv (8)

In determining the exposure time Tvco of the CCD 203 in the test exposure of the electronic viewfinder 1, the sensitivity ratio ΔSv of the member to be exposed is determined by the camera 5 during photographing.
Since the aperture ratio ΔAv is determined by the aperture value Avf set by the camera 5 at the time of photographing, the sensitivity ratio ΔSv and the aperture ratio ΔAv are determined each time test exposure is performed. It is necessary to input the information of the exposure control values Tvf, Avf, the open aperture value Avo and the film sensitivity Svf calculated by the camera 5 to the electronic viewfinder 1 side for calculation. However, since the brightness ratio ΔBv of the exposure surface is determined by the combination of the electronic viewfinder 1 and the camera 5, it is sufficient to calculate the calibration data at least once before the first test exposure is performed.

Therefore, a calibration mode can be set in the electronic viewfinder 1 according to the present embodiment, and the brightness ratio ΔBv of the exposed surface can be calculated in the calibration mode and stored in the RAM 308b in advance. It has become. In the case where the default value of the luminance ratio ΔBv is stored in the ROM 308a, the default value is set to RA when the CPU 308 is activated.
Since M308B is set, it is not enough to set the luminance ratio ΔBv again in the calibration mode in a camera system that can use the default value.

Further, when test exposure is performed by the electronic viewfinder 1 in order to monitor the finish of photographing, the exposure control values Tvf, Av are transmitted from the camera 5 through communication.
f, the aperture value Avo and the film sensitivity Svf are obtained, and the exposure time Tvco is calculated by the above equation (8) using the information and the data of the luminance ratio ΔBv stored in the RAM 308b. CC on Tvco
The exposure of D203 is controlled to capture a still image for monitoring. Then, the still image (monitor image) is displayed on the LCD display unit 301 of the monitor device 3.

The photographer performs a test exposure with the electronic viewfinder 1 to display a monitor image having almost the same finishing condition as that of the photographing on the monitor device 3 to confirm the finished state of the photographing before photographing. it can. If it is determined that the exposure conditions set by the camera 5 are appropriate, the shutter button 60
Pressing 1 may perform the actual photographing. However, if the finished state of the monitor image is not intended, the photographer changes the exposure control value set by the camera 5 to newly set the exposure condition for the desired finished state. Must be set to

The electronic viewfinder 1 according to the present embodiment is provided with a function of changing the exposure control value at the time of test exposure. The test exposure is repeated by changing the exposure time Tvco of the CCD 203 to obtain a desired finished state. Exposure conditions (shutter speed Tvf of the camera 5) can be determined.

At the time of test exposure, the exposure time T on the imaging device 2 side
When vco is changed to Tvco ', the shutter speed T on the camera 5 side is set based on the changed exposure time Tvco'.
vf 'is calculated, and the calculation result is transmitted to the camera 5 by communication.
And the exposure conditions (Tvf ', Av
f) is changed automatically. Note that, as shown in the above equation (8), the exposure time Tvco of the CCD 203 and the exposure time Tvf of the film F are Tvco = Tvf + ΔBv + ΔSv
+ ΔAv, and the correction term (ΔBv + ΔSv + ΔAv) is not changed in the test exposure.
When the exposure time Tvco of D203 is changed to Tvco ', the exposure time Tvf' of the film F to be changed becomes Tvc
f ′ = Tvco ′ − (ΔBv + ΔSv + ΔAv)

If the communication function is not provided, the shutter speed Tvf calculated by the camera 5 may be manually changed to the corrected shutter speed Tvf '.

(2) Flash Shooting In flash shooting, it is generally difficult to set an appropriate amount of illumination of the flash. Therefore, it is more difficult to monitor a flash shot before shooting as in the case of steady light shooting. Flash 307 at the time of actual shooting while watching the monitor image
It is more important to set an appropriate exposure.

In flash photography, the exposure time depends on the flash time of the flash, so factors related to the amount of exposure of the surface to be exposed are the flash emission distance and the aperture value of the photographing optical system. In flash photography with automatic adjustment of the amount, usually, the aperture is determined with priority and the flash duration is controlled to determine the flash emission level by the distance between the subject and the flash at the time of shooting. The quantity is made to be.

Therefore, in flash photography, since the exposure amount of the surface to be exposed is determined by the aperture value and the flash emission amount, the appropriate exposure amount of the flash 307 is determined while checking the finished condition on the monitor image. It is necessary to correct this exposure amount so as to set an appropriate light emission amount of the flash 307 at the time of actual photographing.

Assuming that the F number of the taking lens is Fno, the brightness of the film surface is I [lx], the film sensitivity is S, the light emission amount of the flash required for obtaining proper exposure is G, and the proportionality constant is K, G = K · Fno / (S · I) (9)

Therefore, if the equation (9) is expressed by an apex value, Gv = Av−Sv−Iv (10), and the brightness of the film surface of the camera 5 is represented by Iv.
f, the light emission amount of the flash in the actual shooting is Gvf,
Assuming that the brightness of the CCD surface in the imaging device 2 is Ivc, the light emission amount of the flash in the test exposure is Gvc, and the test exposure is performed with the same aperture value Avf as the main photographing,
From equation (10), Gvf = Avf−Svf−Ivf (11) Gvc = Avf−Svc−Ivc (12)

By subtracting equation (12) from equation (11), Gv
f-Gvc = (Svc-Svf) + (Ivc-Ivf)
Since Svc−Svf = ΔSv, Ivc−Svc−Svf = ΔSv
If Ivf = ΔIv, However, ΔGv = ΔSv + ΔIv.

That is, in the actual photographing, if the light emission of the flash 307 is controlled with the light emission amount Gvf obtained by correcting the light emission amount Gvc of the flash 307 during the test exposure by the correction amount ΔGv, the photographer determines that the monitor image is appropriate. A flash photographed image having a finished state can be obtained.

In the flash photography, if the finished state of the photographed photograph confirmed by the first test exposure is a desired finished state, the guide number Gvc set in the test exposure is corrected by the above equation (14). The actual photographing may be performed by causing the flash 307 to emit light at the light emission amount Gvf. However, if the finished state of the first monitor image is not intended, the photographer repeats the test exposure while changing the light emission amount of the flash 307. By determining the light emission amount Gvc 'for obtaining a desired finished state, the light emission amount Gv
The flash light emission amount at the time of the actual photographing is corrected by c ′, and the corrected light emission amount Gvf ′ = Gvc ′ +
The light emission amount of the flash 307 is controlled by ΔGv ′, and a flash image having a desired finish can be obtained.

When the aperture amount of the aperture 702 at the time of test exposure is set to the open aperture value Avo, the aperture ratio ΔAv (= Avf −Avo) is added to the correction amount ΔGv, However, the light emission amount of the flash 307 at the time of actual photographing may be determined based on ΔGv ′ = ΔSv + ΔIv + ΔAv.

Since the brightness ratio ΔIv in flash photography is equivalent to the luminance ratio ΔBv in steady light photography, when calculating the correction amount ΔGv in flash photography, it was set in the calibration mode at the beginning of the system configuration. The luminance ratio ΔBv may be used as ΔIv.

The above description is for the case where an appropriate light emission amount of the flash 307 is set from the monitor image. The light emission amount of the flash 307 set in the test exposure is based on the case where the image pickup device 2 exposes. However, the light emission amount of the flash 307 may be set based on the case of shooting with the single-lens reflex camera 5. In this case, the finished state of the flash photographed image in the actual photographing is confirmed on the monitor image as in the case of the steady light photographing. Therefore, in the test exposure, the set light emission amount is subtracted and corrected by the correction amount ΔGv to perform the flash operation. 307 is fired (that is, if the set light emission amount is Gvf and the light emission amount in the test exposure is Gvc, the flash 307 is fired at the light emission amount of Gvc = Gvf-ΔGv), and the image is properly finished. When the state is confirmed, it is preferable that the flash 307 emits light with the light emission amount Gvf in the actual photographing.

Incidentally, as is apparent from a comparison between the above equations (6) and (13), when the aperture value Av is the same, the correction of the exposure control value is performed in both the normal light photography and the flash photography. The term (ΔBv + ΔSv) is the same. This is because the amount of light from the subject is sufficient for steady light photography,
While the aperture value Av and the exposure time Tv are exposure control factors for the exposure member, the flash photography does not provide enough light from the subject, so the aperture value Av and the exposure time Tv are fixed, and the flash for auxiliary illumination of the subject is used. Of light emission Gv
Is the exposure control factor of the exposure member,
This is because all the exposure control factors are the same in controlling the exposure amount of the exposure member.

Therefore, the above equations (6) and (13) indicate that if the difference between the exposure amount of the film F and the exposure amount of the CCD 203 for the same object is equal to the aperture value Av, the difference between the film surface and the CCD surface is obtained. Brightness ratio (that is, the ratio of the amount of light flux from the subject to the film surface and the amount of light reaching the CCD surface) Δ
Bv and the sensitivity ratio .DELTA.Sv between the film F and the CCD 203, the exposure control factor of one of the exposure members is corrected by the luminance ratio .DELTA.Bv and the sensitivity ratio .DELTA.Sv in both the steady light photography and the flash photography. It shows that the exposure control factor of the other exposure member can be determined so as to make the amount the same.

Next, the procedure for setting the luminance ratio ΔBv in the calibration mode will be described with reference to the flowchart of FIG.

FIG. 10 shows the exposure control values Tvf, A calculated by the camera 5 by manually operating the switch of the operation unit 2.
5 is a flowchart illustrating a procedure when information on vf, aperture value Avo, and film sensitivity Svf is input to the electronic viewfinder 1. In the case where the exposure-related information is transmitted to the electronic viewfinder 1 by communication like the camera 5 according to the present embodiment, the information input processing by manual operation in steps # 5 to # 11 is replaced by automatic setting processing by communication. Can be

The electronic viewfinder 1 functions as a viewfinder, and in the finder mode, CAL.
When the SET switch 302b is operated, the calibration mode is set, and the flowchart shown in FIG. 10 is executed.

In the calibration mode, the ratio .DELTA.Bv between the brightness of the film surface and the brightness of the CCD surface is calculated. Therefore, the light reflected from the subject having uniform and standard brightness is applied to the film surface and the CCD surface. It is desirable to make it incident. Therefore, in the calibration mode, the operator directs the camera 5 to the above-described subject and uses the photometry function of the camera 5 or an exposure meter of another member to set an appropriate exposure control value (shutter speed Tvf and After the aperture value Avf) is calculated, CAL. It is set by operating the SET switch 302b.

When the calibration mode is set, first, the display of the moving image on the LCD display unit 301 is stopped (# 1), and "CAL" indicating that the calibration mode is in place is displayed in an appropriate place on the LCD display unit 301. Characters are displayed (# 3, see FIG. 6). Subsequently, the shutter speed Tvf based on the proper exposure on the camera 5 side and the aperture value Av
f, an input mode of the open aperture value Avo and the film sensitivity Svcal at the time of calibration (# 5 to # 13)
Loop). After operating the SEL switch 302e to select an input item, the operator operates the up switch 302f or the down switch 302g for each input item to set and input a predetermined numerical value.

FIG. 11 is a flowchart showing a process for setting the shutter speed Tvf. When the calibration mode is set, first, the input mode of the shutter speed Tvf is set, and “SS” is displayed on the LCD display unit 301.
XXXX "is displayed. When the default value is different from the shirt speed Tvf to be set, when the operator operates the up switch 302f or the down switch 302g, the display value is increased or decreased by one step for each operation (# 31 to # 39). When the operator operates the SEL switch 302e when the display value reaches the shutter speed Tvf to be set (YES in # 39), the shutter speed Tvf is set, and the next input item (aperture value) is set. ). In the process of setting the aperture value Avf, the aperture value Avf to be set is set in the same procedure as the shutter speed Tvf, and thereafter, the open aperture value Avo and the film sensitivity Svcal to be set are set in the same manner.

After the values to be set for all the setting items are set, the operator sets the TR switch 302
When d is operated (YES in # 13), photometry is performed by the imaging device 2, and the LCD display unit 30 is operated based on the photometry result.
The exposure time Tvc of the CCD 203 for obtaining a standard finished density at 1 is calculated (# 17). The photometric processing is performed using an image captured by exposing for a predetermined time by the CCD 203.
vc, the aperture 702 is an open aperture.
The exposure time Tvc is calculated from the equation c = Tvc + Avo. In this embodiment, the CCD 203 is also used as a photometric sensor, but a photometric sensor for exclusive use may be provided to perform photometry.

Subsequently, the shutter speed Tv of the camera 5
f is the shutter speed Tvf at the open aperture value Avo
o (# 19). This conversion is Tvfo + Av
From o = Tvf + Avf, Tvfo = Tvf + (Avf−
Avo) is performed by the conversion formula.

Subsequently, the brightness Bvf of the film surface and the CCD
The luminance ratio ΔBv with the surface luminance Bvc is calculated (# 2
1). In the calibration mode, Becomes

Therefore, the luminance ratio ΔBv (= Bvc−Bv
f) is calculated by ΔBv = ΔTv−ΔSvcal (17) where ΔTv = Tvc−Tvfo ΔSvcal = Svc−Svcal.

Subsequently, the calculated exposure time ratio ΔTv and sensitivity ratio ΔSvcal are stored in the RAM 308b (#
23), after the moving image display on the LCD display unit 301 is resumed (after switching to the finder mode) (# 25),
The processing in the calibration mode ends.

Next, the procedure of test exposure for monitoring the finished state of a photographed photograph in the ordinary light photographing with the electronic viewfinder 1 will be described with reference to the flowchart of FIG. This flowchart also shows the exposure control values Tvf and Avf calculated by the camera 5 and the open aperture value Av.
o and the information of the film sensitivity Svf are manually input to the electronic viewfinder 1.
When the information relating to the exposure condition is input to the electronic viewfinder 1, the information input processing by manual operation in steps # 45 to # 51 is replaced by the automatic setting processing by communication.

When the SEL switch 302e is operated while the electronic viewfinder 1 is operating in the finder mode (YES in # 41 and # 43), the camera 5 for determining the exposure time Tvc of the CCD 203 in the test exposure. The input mode of the exposure-related information on the side is set (#
45 to # 51). The input processing of the exposure-related information on the camera 5 side is performed in steps # 5 to # 11 of the flowchart shown in FIG.
Is the same as the processing of The operator selects an input item and operates the up / down switches 302f and 302g to set the exposure condition (shutter speed Tvf,
Aperture Avf), open aperture value Avo and film sensitivity Sv
Enter f. In this case, since the open aperture value Avo and the film sensitivity Sv are initially set to the values set in the calibration mode, there is no need to perform a new input operation unless they are changed during the test exposure.

If SEL switch 302e is not operated (NO in # 43), the flow shifts to step # 55 to execute CA
L. It is sequentially determined whether or not the SET switch 302b, the MR switch 302c, and the TR switch 302d have been operated (# 55 to # 59). If none of the switches has been operated (NO in # 55 to # 59), the step is performed. #
43, until one of the switches is operated,
The finder mode is displayed on the CD display section 301 (# 43 to # 59 loop).

On the other hand, CAL. When the SET switch 302d is operated (YES in # 55), the above-described processing in the calibration mode is performed. When the MR switch 302d is operated (YES in # 57), if a test exposure has already been performed, a still image (monitor image) obtained in the test exposure and stored in the display memory 313.
Is performed on the LCD display unit 301. This reproduction process will be described later.

If the TR switch 302d is operated (YES in # 59), the flow shifts to step # 61 to perform test exposure and reproduction processing of the exposed image (# 61).
~ # 71). That is, first, the exposure time Tvco of the CCD 203 in the test exposure is calculated by the above equation (8) using the exposure-related information ΔTv and the sensitivity ratio ΔSvcal of the exposure time and the exposure-related information on the camera 5 side stored in the RAM 308b (# 61).

The film sensitivity S in the test exposure was
If vf is the same as the film sensitivity Svcal when calculating the luminance ratio ΔBv in the calibration mode,
The sensitivity ratio ΔSvcal in the calibration mode can be used as the sensitivity ratio ΔSv in the equation (8). Therefore, from equation (17), ΔBv = ΔTv−ΔSvcal =
Since ΔTv−ΔSv is substituted into Expression (8), the exposure time Tvco of the CCD 203 becomes Is calculated by

If the sensitivity of the film F set in the camera 5 during test exposure is different from the sensitivity during calibration, ΔSv−ΔSvcal = (Svc−Sv
f) + (Svc-Svcal) =-(Svf-Svca
l) = − ΔBvf, the exposure time Tvco is Is calculated by

Subsequently, at the set exposure time Tvco, C
A test exposure is performed by controlling the exposure operation of the CD 203 (# 63). When the exposure is completed, the image signal stored in the CCD 203 is read out to the monitor device 3 (# 6).
5), A / D conversion circuit 311, video signal processing circuit 312
After a predetermined signal processing is performed in the display memory 313, the signal is temporarily stored in the display memory 313, read out by the LCD driver 314, and based on the image data, the LCD display unit 301
Is driven, the image captured by the test exposure (that is, the monitor image) is displayed on the LCD display unit 301 (# 67).

At the same time when the monitor image is displayed on the LCD display section 301, a timer (not shown timer incorporated in the CPU 308) for counting the display time is started (# 69), and the predetermined display time is started. When the time has elapsed (YES in # 71), the flow returns to step # 41, and the display is automatically switched to the viewfinder mode.

In the test exposure, the aperture 702
May be set to the aperture value Avf at the time of the main photographing. By doing so, in equation (18), the aperture ratio Δ
Since Av becomes 0, the exposure time Tvc of the CCD 203 is obtained.
Is calculated by Tvc = Tvf + ΔTv, and the arithmetic expression is simplified.

In displaying the monitor image on the LCD display unit 301, the exposure control value (shutter speed Tv
f, the aperture value Avf) and the film sensitivity Svf are also displayed on the LCD display unit 301 so that their contents can be checked.
Since this is the same as the monitor image reproducing process by c, it will be described together with the description of the reproducing process.

The test exposure for monitoring the state of the flash illumination in the flash photography with the electronic viewfinder 1 is basically performed according to the flowchart of FIG. In this case, the dimming level corresponding to the guide number Gvc previously set in the monitor device 3 before the test exposure is set in the comparator 310d of the dimming circuit,
When the TR switch 302d is operated, the exposure of the CCD 203 is started, and at the same time, the flash 307 is emitted at a predetermined emission timing, and at the same time, the dimming is started.

When a light control signal is output from the light control circuit (when the light emission amount of the flash 307 reaches the light control level), the light emission of the flash 307 is stopped, and when a predetermined exposure time Tvc elapses, The exposure operation of the CCD 203 is stopped. Thereafter, the image signal accumulated from the CCD 203 is read out to the monitor device 3 and the A / D conversion circuit 3
11. After predetermined signal processing is performed by the video signal processing circuit 312, the signal is temporarily stored in the display memory 313, read out by the LCD driver 314, and drives the display unit 301 based on the image data. As a result, the monitor image captured by the test exposure is displayed on the LCD display unit 3.
01 is displayed.

Next, the process of reproducing the monitor image will be described with reference to the flowchart shown in FIG.

When the MR switch 302d is operated, the image data of the picked-up image is read out from the display memory 313 to the LCD driver 314, and based on the image data, the L data is read out.
By driving the CD display unit 301, a monitor image is displayed on the LCD display unit 301 (# 73). Also,
At the same time, the counting of the timer for counting the display time is started (# 75).

Subsequently, a character display of "MR" indicating that the monitor image is being reproduced is displayed over the monitor image, and the correction amount ΔGv of the light emission amount of the flash 307 is displayed.
Is displayed (# 77, # 79, see FIG. 6). When the SEL switch 302e is operated (YES in # 81), the display is switched to the exposure control value (shutter speed Tvf, aperture value Avf) of the camera 5 (# 85), and the SEL switch 302e is further operated. Then (Y at # 87
ES), and switched to the film sensitivity Svf (# 9)
1) Thereafter, each time the SEL switch 302e is operated (YES in # 81, # 87 or # 93), the correction amount ΔGv of the flash emission amount and the exposure control value (shutter speed T
vf, aperture value Avf) and film sensitivity Svf are cyclically switched.

When the predetermined display time is counted by the timer (YE in # 83, # 89 or # 95)
S), the flow returns to step # 41, and the display is automatically switched to the finder mode display.

As described above, the calibration mode can be set, and in the calibration mode, the luminance ratio ΔBv between the film surface and the CCD surface is calculated in advance and R
Since the image data is stored in the AM 308b, the film F in the test exposure is used based on the shutter speed Tvf and the luminance ratio ΔBv in the main shooting in the normal light shooting.
It is possible to easily calculate an appropriate exposure time Tvc of the CCD 203 for obtaining a captured image having substantially the same finished state as a photograph taken on the CCD 203. Further, in the flash photography, the flash 307 in the main photography for obtaining a photographed image having a preferable finished state confirmed in the test exposure based on the light emission amount Gvc of the flash 307 confirmed in the test exposure and the luminance ratio ΔBv. Can be easily calculated.

The electronic viewfinder 1 and the camera 5
When the luminance ratio ΔBv is different due to the combination with the above, or when the luminance ratio ΔBv varies due to individual differences of the cameras 5 of the same model, the accurate luminance ratio By calculating ΔBv, it is possible to always accurately confirm the finished state of photographing before photographing with a monitor image in steady light photographing, and to check the finished state confirmed before photographing in flash photographing. It is possible to reliably control the flash emission in the actual photographing so as to obtain a photographed image having the same.

FIG. 14 is a perspective view showing the configuration of an electronic viewfinder according to a second embodiment of the present invention.

An electronic viewfinder 1 'shown in FIG.
In FIG. 1, the flash 307 is removed from the monitor device 3 to simplify the structure. Monitor device 3
Camera 5 in the right place on the side where the cable 4 is attached
There is provided a connection unit 318 to which a flash device 18 (see FIG. 15) externally connected to the device communicably connects.
The flash device 18 is a flash device that can be used when a camera system is configured by combining the electronic viewfinder 1 ′ and the camera 5, and has a mounting portion 181 on the lower surface thereof for mounting to the shoe 9 of the camera 5. In addition, a connection portion 182 to which the monitor device 3 of the electronic viewfinder 1 'is communicably connected is provided at an appropriate position on one side. The flash device 18 is provided with an operation member (not shown) for setting the amount of light emitted from the flash, and a light control sensor (not shown) is provided in a light control window 183 formed at a proper lower portion on the front surface. The light emission amount of the flash device 18 is controlled to a set predetermined light emission amount based on the amount of flash light received by the light control sensor.

As shown in FIG. 15, the electronic viewfinder 1 'is replaced with the electronic viewfinder 1 according to the first embodiment.
The camera unit 5 is mounted on the shoe unit 9 in the same manner as described above, and the connection unit 318 of the monitor device 3 and the connection unit 182 of the flash unit 18 of the electronic viewfinder 1 ′ are connected to the communication cable 19.
, A camera system capable of flash photography is configured. Then, the electronic viewfinder 1 '
Required data is exchanged between the electronic viewfinder 1 and the flash device 18 via the communication cable 19, and the same control as the flash light emission control of the electronic viewfinder 1 according to the first embodiment is performed.

That is, for example, when setting the light emission Gvc while confirming the lighting condition of the flash light in the flash photographing before photographing with the electronic viewfinder 1 ′, the test exposure from the monitor device 3 to the flash device 18 via the communication cable 19 is performed. The flash emission timing signal of the time is transmitted, and the flash device 18 emits light based on the emission timing signal. At the time of the actual photographing, the correction amount ΔGv of the light emission amount is transmitted from the monitor device 3 to the flash device 18 via the communication cable 19,
The flash device 18 causes the flash to emit light based on a light emission timing signal transmitted from the monitor device 3, and the light amount of the flash light received by the dimming sensor is equal to a predetermined light emission amount Gv.
When f (= Gvc + ΔGv) is reached, emission of light is forcibly stopped to perform appropriate flash emission.

Since the electronic viewfinder 1 'according to the second embodiment does not incorporate the flash 307, the structure can be simplified and the cost can be reduced. Electronic viewfinder 1 'according to the second embodiment
Since it is necessary to prepare a separate flash device 18 when configuring the camera system, it is not as compact as the electronic viewfinder 1 according to the first embodiment. A test exposure is performed in combination with the flash device 18 of the above, and a light emission amount Gvc at which a desired illumination condition can be obtained is set. At the time of actual photographing, a flash is emitted at a light emission amount Gvf obtained by correcting the light emission amount Gvc by the correction amount ΔGv. By doing so, a suitable flash photographed image can be obtained, so that functionally the same effect as in the first embodiment can be obtained.

FIG. 16 is a rear view showing a state where the electronic viewfinder according to the third embodiment is attached to a single-lens reflex camera. FIG. 17 is a front view showing a state where the electronic viewfinder is attached to a single-lens reflex camera.

An electronic viewfinder 1 ″ according to the third embodiment is a modification of the electronic viewfinder 1 ′ according to the second embodiment, and the position of the mounting portion 304 to the camera 5 is set from the bottom of the monitor device 3. Therefore, the monitor device 3 of the electronic viewfinder 1 ″ is attached to the back of the camera 5.

In the electronic viewfinder 1 ″ according to the third embodiment, since the mounting position on the camera 5 is not at the shoe section 9, the external flash device 20 can be mounted on the shoe section 9. Although not shown, in the case where the camera 5 is provided with the built-in flash, the electronic viewfinder 1 ″ is used.
By simply attaching the camera to the camera 5, it is possible to easily configure a camera system capable of checking the illumination state in flash photography.

[0148]

As described above, according to the present invention,
A mode setting unit for a calibration mode is provided. In the calibration mode, a luminance ratio between the luminance of the film surface and the luminance of the imaging surface of the imaging unit is calculated in advance, and the exposure control value of the single-lens reflex camera is calculated by the luminance ratio. Exposure control of the image pickup means in test exposure is performed by the exposure control value corrected using, and the photographing result is displayed on the display means. Therefore, the optical characteristics of the viewfinder system of the single lens camera combined with the electronic viewfinder (mainly, Irrespective of the light amount loss characteristic), it is possible to accurately confirm a captured image having almost the same finishing condition as the photographed image on the film by the test exposure before the actual photographing. In the actual photographing, the exposure control condition is determined based on this confirmation. The desired photographing can be performed by adjusting.

In the calibration mode, test exposure is performed, and the luminance ratio is calculated using the captured image. Therefore, the luminance ratio can be accurately calculated by selecting a subject having appropriate brightness. can do.

When there is a difference between the film sensitivity and the aperture value between the actual photographing and the test exposure, the exposure control value at the time of the actual photographing is corrected in consideration of these differences in the luminance ratio. By the test exposure, an image having a more accurate finished state at the time of actual shooting can be captured.

Further, the exposure control value during the test exposure can be manually adjusted to an appropriate exposure control condition, and the adjusted exposure control value is corrected with the luminance ratio calculated in the calibration mode, thereby obtaining the exposure during the actual photographing. Since the control values can be reset, it is possible to easily and reliably take a photograph having a finish desired by the photographer in the actual photographing.

Further, the electronic viewfinder and the single-lens reflex camera are communicably connected to each other, and the exposure control conditions on the camera side are automatically inputted to the electronic viewfinder by communication. It is easy to set the exposure control value on the electronic viewfinder side in the test exposure, and it is possible to easily monitor the photographed image on the film in the test photographing.

Further, since the electronic viewfinder and the single-lens reflex camera are communicably connected to form a camera system, an image having the same finishing state as a photograph taken on a film can be easily obtained by the electronic viewfinder before the actual photographing. In addition, a camera system capable of accurately checking can be configured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a first embodiment of an electronic viewfinder according to the present invention.

FIG. 2 is a front view showing a state in which the electronic viewfinder according to the first embodiment is attached to a single-lens reflex camera.

FIG. 3 is a rear view showing a state in which the electronic viewfinder according to the first embodiment is attached to a single-lens reflex camera.

FIG. 4 is a perspective view of a main part showing a structure of a mounting portion for mounting an electronic viewfinder of the single-lens reflex camera.

FIG. 5 is a diagram showing a display of input contents when a photographing condition on the camera side is inputted.

FIG. 6 is a diagram showing the relationship between the function of each switch of the operation unit and the display content on the LCD display unit based on the operation.

FIG. 7 is a diagram illustrating a schematic configuration of an optical system of the single-lens reflex camera to which the electronic viewfinder according to the first embodiment is attached.

FIG. 8 is a circuit block diagram of a single-lens reflex camera to which the electronic viewfinder according to the first embodiment is attached.

FIG. 9 is a diagram illustrating an example of a circuit configuration of a light emission control circuit.

FIG. 10 is a flowchart showing a procedure for calculating a luminance ratio in a calibration mode.

FIG. 11 is a flowchart showing a setting process of a shutter speed Tvf.

FIG. 12 is a flowchart illustrating a test exposure processing procedure.

FIG. 13 is a flowchart illustrating a process of reproducing a monitor image.

FIG. 14 is a perspective view showing the configuration of a second embodiment of the electronic viewfinder according to the present invention.

FIG. 15 is a front view showing a state where the electronic viewfinder according to the second embodiment is attached to a single-lens reflex camera, and a flash device is communicably connected to the electronic viewfinder to form a camera system.

FIG. 16 is a rear view showing a state where the electronic viewfinder according to the third embodiment is attached to a single-lens reflex camera.

FIG. 17 is a front view showing a state in which the electronic viewfinder according to the third embodiment is attached to a single-lens reflex camera.

[Explanation of symbols]

1, 1 ', 1 "electronic viewfinder 2 imaging device (imaging device) 201 lens 202 CCD area sensor (photometric device) 3 monitor device 301 LCD display unit (display unit) 302 operation unit 302a power switch 302b CAL.SET switch ( Mode setting means) 302c MR switch 302d TR switch (instruction means) 302e SEL switch (input means) 302f Up switch (input means, adjustment means) 302g Down switch (input means, adjustment means) 303 Power display 304 Mounting section 306 Connection terminal (Output means, input / output terminals) 307 flash 308 control unit (calculation means, imaging control means, luminance ratio calculation means, correction means, communication means) 308a ROM 308b RAM (storage means) 309 xenon tube 310 flash circuit 311 A / D conversion circuit 312 Video signal processing circuit 313 Display memory 314 LCD driver 315 Timing control circuit 316 Switch circuit 317 Switch group 318 Connection section 4 Cable 5 Single-lens reflex camera 6 Camera body 601 Lens mounting section 602 Shutter button 603 Switch group 604 AF Control unit 605 Aperture control unit 605 Distance measurement unit 606 Photometry unit 607 Aperture control unit 608 DX reading unit 609 CPU (communication means) 7 Interchangeable lens 8 Eyepiece frame unit 9 Shoe unit 904 Contact point (connection terminal) 10 Eyepiece lens 11 Pentaprism 12 Condenser lens 13 Fresnel focus plate 14 Main mirror 15 Sub-mirror 16 Photometric sensor 17 Connector 18, 20 Flash unit 182 Connection unit 19 Communication cable

Continued on the front page F term (reference) 2H002 AB01 DB02 DB04 DB08 DB19 DB24 FB02 FB03 FB23 FB24 FB25 FB28 FB52 FB53 FB81 GA00 GA35 GA68 GA70 GA73 HA04 HA11 JA02 2H018 AA00 AA21 BE01 BE02 BE05 2H102 AA02 AA03 AA03 AA08 CA32 5C022 AA13 AB03 AB15 AB17 AB40 AC02 AC03 AC07 AC42 AC54 AC78

Claims (7)

[Claims] 1. An image pickup means detachably attached to a finder window of a single-lens reflex camera, for taking an optical image of a subject guided to the finder window, an instruction means for instructing a still image to be taken, and the instruction means When imaging is instructed, arithmetic means for calculating an exposure control value of the imaging means; imaging control means for controlling imaging of the imaging means based on the exposure control value calculated by the arithmetic means; Display means for displaying a still image picked up in the step (a), wherein the same subject is imaged by the image pickup means before the actual photographing on the film, and the photographed image is displayed on the display means, so that the image before the actual photographing is obtained. In an electronic viewfinder capable of confirming a finished state of a photograph, a photometric unit for measuring the luminance of an imaging surface of the image capturing unit, and an object that is the same as a photometric target of the photometric unit. Input means for inputting information relating to the exposure of the single-lens reflex camera, mode setting means for setting a calibration mode, and, in the calibration mode, the luminance measured by the photometry means for the same subject and A luminance ratio computing unit that computes a luminance ratio between the luminance of the film surface and the luminance of the imaging surface of the imaging unit based on the information on the exposure of the single-lens reflex camera input from the input unit; Storage means for storing the calculated luminance ratio, wherein the arithmetic means is based on the information on the exposure of the single-lens reflex camera at the time of the actual photographing input from the input means and the luminance ratio stored in the storage means And calculating an exposure control value of said imaging means that can obtain an exposure amount substantially equal to an exposure amount on the film. Finder. 2. The electronic viewfinder according to claim 1, wherein said brightness ratio calculation means calculates a brightness ratio when a still image is instructed by said instruction means in a calibration mode. Electronic viewfinder characterized by the following. 3. The electronic viewfinder according to claim 1, wherein the information relating to the exposure of the single-lens reflex camera includes at least an exposure control value and a film sensitivity, and wherein the calculating means includes: A ratio ΔAv between the aperture value and the aperture value at the time of the actual photographing, and a ratio ΔSv between the film sensitivity and the sensitivity of the imaging unit are calculated, and a luminance ratio ΔBv between the film surface and the imaging surface is added to the calculation result. An electronic view finder for calculating an exposure control value of the image pickup means by correcting an exposure control value at the time of actual photographing with a correction value (ΔBv + ΔSv + ΔAv). 4. The electronic viewfinder according to claim 1, wherein the adjusting means for manually adjusting the exposure control value of the imaging means calculated by the calculating means, and the adjusted exposure control value and the storing means. Correction means for correcting the exposure control value in the single-lens reflex camera at the time of the main photographing based on the stored luminance ratio; and output means for outputting the exposure control value corrected by the correction means. Electronic viewfinder. 5. The electronic viewfinder according to claim 4, wherein the input means and the output means include an input / output terminal to which the single-lens reflex camera is communicably connected, information on exposure of the single-lens reflex camera, and information after correction. An electronic viewfinder, comprising: communication means for communicating with the single-lens reflex camera so as to input and output the exposure control value to and from the single-lens reflex camera by communication. 6. A single-lens reflex camera to which the electronic viewfinder according to claim 5 is communicably connected, wherein the information is related to an exposure of the single-lens reflex camera and is corrected after being connected to an input / output terminal of the electronic viewfinder. Communication means for communicating between the connection terminal from which the exposure control value is output and the electronic viewfinder so as to input and output information on the exposure of the single-lens reflex camera and the corrected exposure control value to and from the electronic viewfinder. A single-lens reflex camera characterized by comprising input / output means comprising: 7. The single-lens reflex camera according to claim 6, wherein the imaging means of the electronic viewfinder according to claim 5 is detachably attached to a finder window, and said input means and output means of said electronic viewfinder are said single-lens camera. A camera system communicably connected to input / output means of a reflex camera.