JP2000032323A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera capable of photographing by more exactly performing AF or exposure while shortening a time lag in the case of photographing. SOLUTION: By providing a movable mirror 5 with a half mirror 6, even just while performing observation through an optical finder system 10, the image of an object is formed on an imaging device 12 and measured by respective AF circuit 15, AE circuit 16 and AWB circuit 17. Concerning such an electronic camera, the respective AF, AE and AWB values measured through the half mirror 6 are corrected based on a correction value which is previously stored in a system controller 18, with respect to the influence component of the half mirror 6 so that the electronic camera can immediately store the image in a storage medium 28 before the lapse of time required for every measuring operation again after the mirror 5 is moved up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electronic camera, and more particularly, to an electronic camera provided with a reflection mirror having a transflective portion.

[0002]

2. Description of the Related Art Images taken by an image pickup device such as a CCD are
An electronic camera that performs photographing while observing with a video display device such as an LCD is commercially available, but the LCD has a small number of pixels as compared with a CCD, and is not enough to confirm the composition and the like of a subject. However, it was not enough to observe the focus state in detail.

In view of the above, there has been proposed an electronic camera further provided with a single-lens reflex type finder optical system in addition to the image display device, and an object image incident from a photographing optical system is brightened through the finder optical system. It can be observed with high definition.

However, in such a single-lens reflex optical system, when a subject is optically observed, a light beam incident from the photographing optical system is reflected toward a finder optical system by a reflection mirror such as a quick return mirror. However, at this time, since the subject light does not reach the image sensor side,
Observation by the video display device cannot be performed simultaneously, and furthermore, AF, AE, AWB, etc. cannot be performed simultaneously. Therefore, AF, AE, AWB, and the like must be performed after the reflection mirror is retracted from the optical path by pressing the release switch, and there is a problem that a time lag from when the release switch is pressed to when recording is performed on the recording medium becomes long. Was.

The applicant of the present invention has proposed in Japanese Patent Application No. 10-96314 an electronic camera having a structure in which a transflective portion is provided in a part of a reflecting mirror such as a quick return mirror. When the reflecting mirror is in the state of entering the photographing light beam, a part of the light beam is reflected to the finder optical system side and another part of the light beam is transmitted to the image pickup device side. Even while observing the subject with the system, the image pickup device side can receive the subject light beam and perform the shooting preparation operation such as AF, AE, AWB, etc. When the release switch is pressed, the recording is quickly performed. The time lag can be shortened.

[0006]

However, in the configuration described in Japanese Patent Application No. 10-96314,
In a shooting preparation state in which the reflection mirror is positioned on the optical path and in a shooting operation state in which the reflection mirror is retracted from the optical path, the light beam that reaches the image sensor has passed through the translucent portion of the reflection mirror. A difference occurs based on whether or not.

More specifically, the semi-transmissive portion is formed by evaporating a semi-transmissive mirror on a light-transmitting thin plate, for example.
When the light passes through the semi-transmissive portion, the light may attenuate, the color balance may change, or the optical path length may change.

In recent years, the number of pixels of an image sensor has been increased, and AE, AWB
It is desirable to correct such a change in order to perform more appropriate photographing with the increase in accuracy of the camera. However, in the above-described conventional electronic camera, the AF, AE, and AWB obtained in the photographing preparation state are used. Each value needs to be corrected again by performing AF, AE, and AWB in a shooting state in which the reflection mirror is retracted from the optical path, so that a time lag eventually occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an electronic camera capable of performing more accurate photographing while reducing the time lag during photographing.

[0010]

In order to achieve the above object, an electronic camera according to a first aspect of the present invention includes a focus lens for adjusting a focal position, and forms an object image relating to an incident light beam. Photographic optical system, an image sensor that photoelectrically converts a subject image formed by the photographic optical system and outputs an electric signal, and optically transfers the subject image formed by the photographic optical system to a photographer's eyes. A finder optical system for guiding, and a position of a light beam reflection that is located on an optical path through which the light beam passes and reflects at least a part of the light beam toward the finder optical system, and retracts from an optical path through which the light beam passes. A reflecting mirror configured to be able to selectively take a posture of passing the light beam to the image pickup device side, and one of the light beams when the reflecting mirror takes the posture of reflecting the light beam. And a semi-transmissive reflection portion provided on the reflection mirror to reflect another part of the light flux to the image sensor side while reflecting the light beam to the finder optical system side, and the electric signal output from the image sensor. A focus position detecting means for determining a focus position of the focus lens based on the focus position; and a focus for moving the focus lens to a predetermined position by referring to information of the focus position determined by the focus position detection means. Lens control means,
When the reflection mirror is displaced from one of the attitude of light flux reflection and the attitude of light flux passage to the other, the focus lens control means is determined by the in-focus position detection means before performing the displacement. The focus lens is controlled so as to move from the in-focus position to a position for correcting an amount equivalent to the optical path length of the transflective portion.

In the electronic camera according to a second aspect of the present invention, in the electronic camera according to the first aspect, the focus lens control means is determined by the focusing means when the reflection mirror takes the light flux reflecting posture. The focus lens is moved to the focused position, and when the reflecting mirror is displaced from the light beam reflecting position to the light beam passing position, the focus lens is moved to a position for correcting the light path length equivalent to the transflective portion. This is to control to move the lens.

Further, an electronic camera according to a third aspect of the present invention includes:
In the electronic camera according to the first aspect of the present invention, the focus lens control means may determine an optical path length of the semi-transmissive reflector from a focus position determined by the focus means when the reflection mirror is in the light flux reflecting position. The focus lens is controlled so as to be moved to a position where a considerable amount of correction is performed, and the focus mirror is controlled so as not to move after the reflection mirror is displaced from the light flux reflection posture to the light flux passage posture. is there.

According to a fourth aspect of the present invention, there is provided an electronic camera for photographing an optical system for forming a subject image related to an incident light beam, and an image pickup for photoelectrically converting the subject image formed by the photographing optical system and outputting it as an electric signal. An element, a finder optical system for optically guiding a subject image formed by the imaging optical system to a photographer's eye, and at least a part of the finder positioned on an optical path through which the light passes. A reflection mirror configured to be able to selectively take a posture of light beam reflection to be reflected on the optical system side and a light beam passing posture of retreating from an optical path through which the light beam passes and passing the same light beam to the image pickup device side, When the reflection mirror takes the posture for reflecting the light beam, the mirror reflects a part of the light beam to the finder optical system side and transmits another part of the light beam to the image pickup device side. A semi-transmissive reflection unit provided on a projection mirror; and exposure control means for controlling exposure by determining an exposure value based on the electric signal output from the imaging element, wherein the reflection mirror reflects the light beam. In the case where the exposure control means is displaced from one of the attitude of the light beam and the attitude of passing the light beam to the other, the exposure control means adjusts the light amount by the transflective portion from the exposure value determined before the displacement. The exposure value is corrected to control the exposure.

According to a fifth aspect of the present invention, there is provided an electronic camera for photographing an optical system for forming a subject image related to an incident light beam, and an image pickup for photoelectrically converting the subject image formed by the photographing optical system and outputting it as an electric signal. An element, a finder optical system for optically guiding a subject image formed by the imaging optical system to a photographer's eye, and at least a part of the finder positioned on an optical path through which the light passes. A reflection mirror configured to be able to selectively take a posture of light beam reflection to be reflected on the optical system side and a light beam passing posture of retreating from an optical path through which the light beam passes and passing the same light beam to the image pickup device side, When the reflection mirror takes the posture for reflecting the light beam, the mirror reflects a part of the light beam to the finder optical system side and transmits another part of the light beam to the image pickup device side. A semi-transmissive reflector provided on the projection mirror, and white balance control means for controlling a white balance by determining a white balance value based on the electric signal output from the image sensor, wherein the reflection mirror is In the case where one of the posture of the light beam reflection and the posture of the light beam passage is displaced to the other, the white balance control means determines the white balance by the transflective unit from the white balance value determined before the displacement. The white balance is corrected by correcting the white balance value by an amount corresponding to the change in the white balance.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of an electronic camera, and FIG. 2 is a flowchart showing an operation of the electronic camera when shooting.

As shown in FIG. 1, the electronic camera has a photographing optical system 1 for forming a subject light image.
The photographing optical system 1 includes an aperture device 2 for adjusting the amount of light passing through a subject light beam and a focus lens 3 for adjusting a focal position.

A mirror 5, which is a movable reflecting mirror such as a quick return mirror, is provided on the optical path of the photographing optical system 1, and this mirror 5 is in the optical path and reflects a light beam. At times, the reflected light beam enters the finder optical system 10.

The finder optical system 10 includes a focusing screen 7 provided on the focal plane of the photographing optical system 1 and a pentaprism 8 for converting a subject image formed on the focusing screen 7 into an erect image. And an eyepiece 9 for enlarging an image projected from the pentaprism 8 and projecting the enlarged image to the photographer's eye.

The mirror 5 has a half mirror 6 as a semi-transmissive reflector at least in a part thereof, so that a part of the light beam of the subject is transmitted even when the mirror 5 is located in the optical path.

An optical image of the subject is placed on the focal plane position of the photographing optical system 1 on the optical path of the light beam transmitted through the half mirror 6 or on the optical path of the light beam when the mirror 5 is retracted from the optical path. Image sensor 1 that converts and outputs as an electric signal
2 are provided.

The output of the image pickup device 12 is
After a predetermined signal processing is performed by the A / D converter 14, the signal is converted into a digital signal by the A / D converter 14.

This digital signal is used to calculate the distance to the subject and determine the in-focus position of the focus lens 3 as an auto-focus (AF) as a focus position detecting means.
A circuit 15, an automatic exposure control (AE) circuit 16 which constitutes an exposure control means for calculating the brightness of the subject and determining the exposure value, and a white balance control for calculating and determining the white balance value of the subject An AF value, an AE value, and an AWB, which are respectively input to an auto white balance (AWB) circuit 17 constituting
The value is output to the system controller 18.

The system controller 18 controls these AF based on predetermined data and program lines.
The value, the AE value, and the AWB value are evaluated, whether or not they are appropriate values is determined, and control is performed so that each circuit performs necessary correction according to the result.

That is, the AF obtained from the AF circuit 15
If it is determined that the focus position needs to be adjusted based on the value, a command to that effect is sent to the focus motor drive circuit 20 as the focus lens control means to drive the focus motor 21 and move the focus lens 3. To adjust the focal position to an appropriate position.

If it is determined that the exposure needs to be adjusted based on the AE value obtained from the AE circuit 16, a command to that effect is sent to the aperture driving circuit 19 and the aperture device 2 is controlled.
Is driven to adjust the aperture amount to an appropriate value, and by controlling the charge accumulation time by the image pickup device 12, the shutter time of a so-called element shutter is adjusted, or the gain of the signal by the image pickup circuit 13 is adjusted. .

Further, the AW obtained from the AWB circuit 17
When it is determined that the white balance needs to be adjusted based on the B value, a command to that effect is sent to the image pickup circuit 13 to adjust the color balance by changing the amplification factor of each color.

Also, the system controller 18
The drive control of the mirror 5 is also performed. That is, when a photographing instruction is given by the release switch 31 composed of a two-stage switch, a necessary control command is sent to the drive circuit 22 to drive the drive motor 23 so that the mirror 5 is retracted from the optical path. When the exposure of the image sensor 12 is completed, the mirror 5 is returned to the optical path again.

On the other hand, the output of the A / D converter 14 is temporarily stored in a memory 24, then output to an LCD 26 via an LCD interface (I / F) 25, and
Images are displayed on the CD 26.

When the release switch 31 is turned on, the image data stored in the memory 24 is compressed by the compression / expansion circuit 27 and then, for example, by a memory card detachable from the electronic camera. Is recorded on a recording medium 28.

In addition to the release switch 31, the system controller 18 further includes a mirror-up mode switch 32 for retracting the mirror 5 from the optical path, and a finder optical system 10 for photographing. And a finder selection mode switch 33 for setting whether to mainly perform observation via the LCD 26 or mainly to observe via the LCD 26.

Next, the operation of the electronic camera at the time of shooting will be described with reference to FIG.

Waiting for the power of the electronic camera to be turned on (step S1), when the electronic camera is turned on, it is determined whether or not a mirror up mode as described later is set by the state of the mirror up mode switch 32. Is determined (step S2).

If it is determined that the mirror-up mode has not been set, the mirror-up mode is set after the release. At this time, an optical system for performing photographing while mainly observing the finder optical system 10 is further provided. It is determined by detecting the state of the finder selection mode switch 33 whether the finder mode or the LCD observation mode in which photographing is performed while mainly observing the LCD 26 (step S3).

If it is determined that the mode is not the optical viewfinder mode, the subject image formed by the photographing optical system 1 via the half mirror 6 is photoelectrically converted by the image pickup device 12, and the image pickup circuit 13 and the A / A Input to the AE circuit 16 and the AWB circuit 17 via the D converter 14, respectively.
The AE operation and the AWB operation are performed, and the results are output to the system controller 18. The system controller 18 controls the aperture driving circuit 19 to drive the aperture device 2 and controls the image sensor 12 to adjust the element shutter or control the image sensor 13 based on the result of the AE operation. Then, the exposure is automatically adjusted (AE) by adjusting the gain, and the image pickup circuit 13 is controlled based on the result of the AWB operation to perform the automatic white balance adjustment (AWB) (step S4). .

The output of the A / D converter 14 is also input to the AF circuit 15, and the A / D converter 14
The F operation is performed, and the result is also output to the system controller 18. The system controller 18 controls the focus motor drive circuit 20 to drive the focus motor 21 based on the result of the AF calculation, and moves the focus lens 3 to perform AF (step S5). Since the AE, AWB, and AF in steps S4 and S5 are in the state where the mirror 5 is located in the optical path, the AE value, AWB in the state affected by the half mirror 6 and the like are used.
Value and AF value.

Thereafter, the process waits until the first stage of the release switch 31 is turned on (step S6), and if it is not on, the processes in steps S4 and S5 are performed, and the process waits until it is turned on. When the stage is turned on, AE and AWB are performed again as described above (step S7), and AF is performed (step S8). AE, AW in steps S7 and S8
B and AF are also in a state affected by the half mirror 6 and the like.

Then, after the second stage of the release switch 31 is turned on (step S9), the mirror 5 is retracted from the optical path when it is turned on (step S1).
0) Then, AE and AWB corrections are performed (step S11), and AF correction is performed (step S12).

That is, since a decrease in light amount, a change in color balance, or a change in optical path length due to the presence of the half mirror 6 can be determined in advance at the time of designing, data necessary for correction is required. Are stored in advance in storage means in the system controller 18, and each of the AEs and As detected by using these correction data at the time of correction.
The WB and AF values are corrected.

At the time of performing the operations of steps S11 and S12, the mirror 5 has already been retracted from the optical path.
Although the AE, AWB, and AF corrections can be performed using the data output from the CPU, it is more preferable to perform the correction using the previously stored correction data as described above in consideration of the time required for the calculation. It is desirable that the time lag can be further reduced.

Thus, when in the LCD observation mode, the first stage of the release switch 31 is turned on and the A
When E, AWB, AF, etc. are locked, the LCD
In order to confirm the subject image by 26, the correction of the difference depending on whether the mirror 5 is on the optical path is performed after the second stage of the release switch 31 is turned on.

When this correction is completed, the image sensor 12
The image data stored in the memory 24 is compressed by the compression / expansion circuit 27 and then recorded on the recording medium 28 (step S13).

When the recording is completed, the mirror 5 is returned to the optical path again (step S14) and the processing is terminated.

If it is determined in step S3 that the mode is the optical finder mode, AE and AWB are performed in the same manner as described above (step S15).
AF is performed (step S16). These steps S15
Since AE, AWB, and AF in step S16 are in a state where the mirror 5 is located in the optical path,
AE under the influence of the half mirror 6 and the like
Values, AWB values, and AF values.

Thereafter, the process waits until the first stage of the release switch 31 is turned on (step S17). If not, the processes in steps S15 and S16 are performed to wait for the first stage to be turned on. When the stage is turned on, AE and AWB are performed again (step S18), and AF is performed (step S19). AE, AW in steps S18 and S19
B and AF are also in a state affected by the half mirror 6 and the like.

Therefore, in order to correct these influences,
While performing AE and AWB correction (step S20),
AF correction is performed (step S21).

At the time when this correction has been completed, the settings necessary for photographing have been made.
Wait until the second stage 1 is turned on (step S2
2) When the mirror is turned on, the mirror 5 is retracted from the optical path (step S23), and recording on the recording medium 28 is performed (step S24). When the recording is completed, the mirror 5 is returned to the optical path again (step S25), and the processing is completed.

As described above, in the optical finder mode, it is not necessary to set the display on the LCD 26 to an optimum state in order to perform photographing while observing the finder optical system 10. Since the necessary correction for AE, AWB, and AF can be performed before the stage is turned on, after the second stage of the release switch 31 is turned on, the focus lens can be retracted only by retracting the mirror 5. The recording on the recording medium 28 can be performed without requiring the movement of the third device 3 or the like, and the time lag can be reduced.

On the other hand, if it is determined in step S2 that the mirror-up mode is set,
First, the mirror 5 is retracted from the optical path (step S2).
6). Here, the mirror up mode refers to the mirror 5
In this mirror-up mode, the subject cannot be observed by the finder optical system 10, and the composition and the like are checked by the LCD 26. Will do. This mirror up mode is used when the mirror 5
This mode has the advantage that the time lag from when the release switch 31 is released to when recording on the recording medium 28 is performed is short.

After the mirror 5 has been retracted,
AE and AWB are performed in the same manner as described above (step S27), and AF is performed (step S28). Note that A in these steps S27 and S28
Since E, AWB, and AF are performed in a state where the mirror 5 is raised, they are not affected by the half mirror 6 and the like, and therefore, it is unnecessary to correct the influence thereof.

Thereafter, the control waits until the first stage of the release switch 31, which is a two-stage switch, is turned on (step S29).
And waits for the power to be turned on after performing the processing of step S28.
E and AWB are performed (step S30), and AF is performed (step S31). Similarly, in each of the AE, AWB, and AF processes in steps S30 and S31, correction of the influence by the half mirror 6 or the like is unnecessary.

When the AE, AWB, and AF are completed, the AE value, the AWB value, and the AF value are locked.

Thereafter, the system waits until the second stage of the release switch 31 is turned on (step S32), and when it is turned on, performs recording on the recording medium 28 (step S33).

As described above, in the mirror-up mode, the AE, AWB, and AF corrections are not required, and the recording operation on the recording medium 28 can be performed immediately after the second step of the release switch 31 is turned on. As a result, a time lag hardly occurs, and quick recording can be performed. Therefore, the mirror-up mode is a mode that is particularly effective when, for example, continuously photographing a fast-moving subject.

When photographing is performed again while the mirror-up mode is continued, the above-described photographing process is repeated without performing mirror-down, and when the mirror-up mode ends or the power is turned off. In this case, mirror down processing is performed.

According to such an embodiment, a clear object image can be observed without parallax by the finder optical system, and at the same time, AE,
AWB and AF can be performed, and changes in AE, AWB, and AF due to the insertion of the half mirror in the optical path are corrected using predetermined correction data stored in advance. AE, AWB, AF again
It is possible to perform more accurate shooting while reducing the time lag at the time of shooting without requiring the time for performing the shooting.

Further, in the case of an optical finder mode for mainly observing the finder optical system, AE, AW
Since each correction of B and AF is performed before the second stage of the release switch is pressed, the time lag after the second stage of the release switch is pressed can be further reduced.

In the mirror-up mode in which the image is taken with the mirror retracted from the optical path, AE,
Since the AWB and AF corrections are not required, and the mirror-up after pressing the release switch is not required, it is possible to perform shooting with a further reduced time lag.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications and applications are possible without departing from the gist of the invention.

[0059]

As described above, according to the electronic camera of the present invention, when the attitude of the reflection mirror is displaced, the position of the focus lens before the displacement is equivalent to the optical path length of the transflector. Since correction is performed by the minute, it is possible to perform shooting at a more accurate focus position while reducing the time lag during shooting.

According to the electronic camera of the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained, and more accurate when the posture of reflecting the light beam is changed to the posture of passing the light beam. It is possible to perform shooting at an appropriate focal position.

Further, according to the electronic camera of the present invention, the same effect as that of the first aspect of the present invention can be obtained, and the optical path length of the semi-transmissive reflecting portion is equivalent to the light path length before being displaced to the light beam reflecting posture. Since the minute is corrected, the time lag can be further reduced.

According to the electronic camera of the present invention, when the attitude of the reflecting mirror is displaced, the exposure value before the displacement is corrected by an amount corresponding to the change in the amount of light by the transflective portion. In addition, it is possible to perform shooting with more accurate exposure while reducing the time lag during shooting.

According to the electronic camera of the present invention, when the attitude of the reflecting mirror is displaced, the white balance value before the displacement is corrected by an amount corresponding to the change of the white balance by the transflective portion. As a result, it is possible to perform shooting with a more accurate white balance while reducing the time lag during shooting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic camera according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the electronic camera according to the embodiment at the time of shooting.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 photographing optical system 2 diaphragm device 3 focus lens 5 mirror (reflection mirror) 6 half mirror (semi-transmissive reflector) 10 finder optical system 12 image sensor 15 AF circuit (focusing position detecting means) 16 AE circuit (exposure control means) 17 AWB circuit (white balance control means) 18 system controller 19 iris drive circuit 20 focus motor drive circuit (focus lens control means) 21 focus motor 26 LCD 28 recording Medium 31 Release switch 32 Mirror up mode switch 33 Viewfinder selection mode switch

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 9/73 H04N 5/91 J F term (reference) 2H002 AB01 DB08 DB17 DB19 DB20 EB00 FB21 FB28 FB51 FB73 GA00 GA54 HA05 JA02 JA07 5C022 AA13 AB02 AC00 AC02 AC03 AC18 AC54 AC69 5C053 FA08 GB36 LA06 5C065 AA03 BB02 BB11 CC08 DD02 EE12 EE20 GG26 5C066 AA01 BA13 EA14 KE07 KL02 KM02

Claims (5)

[Claims] 1. A photographing optical system for forming a subject image related to an incident light beam, comprising a focus lens for adjusting a focal position, and a subject image formed by the photographing optical system being photoelectrically converted. An image sensor that outputs an image signal as an electric signal; a finder optical system that optically guides a subject image formed by the photographing optical system to a photographer's eye; and a light beam that is positioned on an optical path through which the light beam passes. Of the light beam reflecting at least a part of the light beam toward the finder optical system side, and a light beam passing posture of retreating from the optical path through which the light beam passes and passing the same light beam to the image sensor side. And a reflecting mirror adapted to obtain a part of the light beam to the finder optical system side and another part of the light beam when the reflecting mirror takes the light beam reflecting position. A semi-transmissive reflection portion provided on the reflection mirror so as to allow the light to pass to the image sensor side; and a focus position detection for determining a focus position of the focus lens based on the electric signal output from the image sensor. Means, and focus lens control means for moving the focus lens to a predetermined position with reference to the information on the focus position determined by the focus position detection means. When the lens is displaced from one of the attitude and the attitude of passing the light beam to the other, the focus lens control means shifts from the in-focus position determined by the in-focus position detection means to the semi-transmissive position before performing the displacement. An electronic camera, wherein the electronic control unit controls the focus lens to move to a position for correcting an amount corresponding to an optical path length of a reflection unit. 2. The focus lens control means moves the focus lens to a focus position determined by the focusing means when the reflection mirror takes the light flux reflecting position. The method according to claim 1, wherein when the posture is changed from the light beam reflection posture to the light beam passage posture, the focus lens is controlled to move to a position for correcting an amount corresponding to an optical path length of the semi-transmissive reflection unit. Item 2. The electronic camera according to item 1. 3. The focus lens control means corrects an amount corresponding to the optical path length of the semi-transmissive reflection part from a focus position determined by the focus means when the reflection mirror takes the light beam reflection posture. And controlling the focus lens not to move after the reflection mirror is displaced from the light beam reflecting position to the light beam passing position. The electronic camera according to claim 1, wherein: 4. An imaging optical system for forming a subject image related to an incident light beam, an imaging element for photoelectrically converting the subject image formed by the imaging optical system and outputting an electric signal, and the imaging optical system. A finder optical system for optically guiding the subject image formed by the photographer to the photographer's eyes, and a light beam positioned on an optical path through which the light beam passes and reflecting at least a part of the light beam to the finder optical system side A reflecting mirror configured to be able to selectively take a posture of reflection, and a posture of light beam passage for retracting from the optical path through which the light beam passes and passing the light beam to the image pickup device side; When taking a posture of light beam reflection, a part of the light beam is provided on the reflection mirror so as to reflect a part of the light beam to the finder optical system side and to pass another part of the light beam to the image pickup device side. A semi-transmissive reflection unit, and exposure control means for determining an exposure value based on the electric signal output from the image sensor to control exposure, and wherein the reflection mirror has a posture and a light flux of the light flux reflection. In the case of displacement from one of the passing postures to the other, the exposure control means changes the exposure value from the exposure value determined before performing the displacement by an amount corresponding to the change in the amount of light by the transflective unit. An electronic camera, which corrects and controls exposure. 5. A photographing optical system for forming a subject image related to an incident light beam, an image pickup device for photoelectrically converting a subject image formed by the photographing optical system and outputting an electric signal, and the photographing optical system. A finder optical system for optically guiding the subject image formed by the photographer to the photographer's eyes, and a light beam positioned on an optical path through which the light beam passes and reflecting at least a part of the light beam to the finder optical system side A reflecting mirror configured to be able to selectively take a posture of reflection, and a posture of light beam passage for retracting from the optical path through which the light beam passes and passing the light beam to the image pickup device side; When taking a posture of light beam reflection, a part of the light beam is provided on the reflection mirror so as to reflect a part of the light beam to the finder optical system side and to pass another part of the light beam to the image pickup device side. And a white balance control means for determining a white balance value based on the electric signal output from the image sensor to control white balance, wherein the reflection mirror reflects the light beam. When the posture is changed from one of the posture and the posture of passing the light beam to the other, the white balance control unit determines a change in the white balance by the transflective unit from the white balance value determined before performing the displacement. An electronic camera wherein the white balance is controlled by correcting the white balance value by an amount.