JPH11119294A - Camera with electronic finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a subject including the depth of field to be confirmed in a state nearer to a photographed result by executing a lens diaphragm control action so that a set diaphragm value or a calculated diaphragm value is attained in an automatic focusing mode. SOLUTION: The camera with an electronic finder is provided with an electronic image pickup element 3 outputting the image signal of a subject image, an electronic finder 10 displaying the image signal of the subject image outputted from the element 3 and a control means 13 executing the lens diaphragm control action and an automatic focusing control action. When the automatic focusing control action is executed, the lens diaphragm control action is executed so that a prescribed diaphragm value is set as it is at a framing and photographing time by the control means 13. Simultaneously, the level of the image signal of the subject image outputted from the element 3 is controlled so that the brightness of the display of the finder 10 becomes constant. Thus, since a diaphragm is controlled so as to be the set diaphragm value when the automatic focusing mode is selected, the depth of the field can be confirmed without executing diaphragming operation even in the midst of framing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera with an electronic finder. In particular, the present invention relates to a camera with an electronic viewfinder that facilitates confirmation of the depth of field during autofocusing and facilitates confirmation of focusing during manual focusing.

[0002]

2. Description of the Related Art In a single-lens reflex camera using a silver halide film, an optical finder for confirming a formed light image of an object through an optical system is provided.
Generally used.

On the other hand, through such an optical finder,
With a single-lens reflex camera that checks the light image of the subject,
The aperture of the lens is opened so that it always looks bright, and the aperture of the lens is reduced to the aperture value set at the time of shooting.

For this reason, when confirming the state of the photographing effect due to the depth of focus, that is, in order to confirm the depth of field, it is necessary to perform a lens-down operation. In this case, there is a drawback that the optical finder becomes dark corresponding to the aperture value, and it becomes difficult to confirm the subject light image.

[0005] For this reason, even in a camera having an auto focus (AF) function, in order to check the depth of field, it is necessary to perform an operation of stopping down the lens. It becomes difficult.

Therefore, an object of the present invention is to make it easy to confirm a subject while always keeping the set aperture value during the AF function, and to open the lens aperture during manual focus. An object of the present invention is to provide a camera that facilitates focusing.

Another object of the present invention is to make it easy to confirm the depth of field at the time of an AF function by using an electronic finder.
An object of the present invention is to provide a camera with an electronic viewfinder that facilitates focusing during manual focusing.

Another object of the present invention is to provide a camera with an electronic finder having a function of reproducing and displaying a photographed image using the electronic finder.

Still another object of the present invention is to enable photographing on a silver halide film, facilitate the confirmation of the depth of field at the time of an AF function by using an electronic viewfinder, and adjust the focus at the time of manual focusing. It is an object of the present invention to provide a camera with an electronic viewfinder which facilitates the camera.

[0010]

In order to achieve the above object, a camera with an electronic finder according to the present invention has, as a basic configuration, an electronic image pickup device for outputting an image signal of a subject image, and an image output from the electronic image pickup device. Electronic finder for displaying an image signal of a subject image to be shot, and control means for performing lens aperture control and autofocus control.

The control means performs lens aperture control so that the aperture value remains set to a predetermined aperture value during framing and photographing during autofocus control, and outputs from the electronic image pickup device. The level of the image signal of the subject image to be displayed is controlled so that the display brightness of the electronic viewfinder becomes constant.

In the manual focus control, the control means controls the lens aperture so that the aperture value is set to an open aperture during framing and to the predetermined aperture value during photographing.

The electronic imaging device is a charge-coupled device, and the level of the image signal of the subject image output from the charge-coupled device is controlled by controlling the output gain of the charge-coupled device or the accumulation time of the charge-coupled device. It does by doing.

With this configuration, when auto focus is selected before shooting, the aperture value is set to the set aperture value, and when manual focus is selected, the open aperture value is set. . Further, the aperture is narrowed down to the set aperture value at the time of photographing with the manual focus selected.

The control of the aperture of the camera with an electronic viewfinder according to the present invention is performed at the aperture value set at the time of auto focus selection. It is possible.

In addition, when the manual focus is selected, since the aperture is wide open, there is an effect that the focus is easily adjusted.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or similar components will be described with the same reference numerals or reference symbols.

FIG. 1 is a diagram showing the configuration of a camera with an electronic finder according to a first embodiment of the present invention. In FIG. 1, a camera body 1 and a lens barrel 2 are indicated by broken line blocks.

The lens barrel 2 controls a lens control microprocessor 21, a lens drive circuit 23 for driving and focusing a photographing lens 22 controlled by the microprocessor 21, and an aperture mechanism 24. Mechanism control circuit 2 for setting and controlling the aperture value
5

The lens control microprocessor 21 comprises:
It receives a control signal from the camera body 1 and sends lens data of the taking lens 22 to the camera body 1 side. Accordingly, the lens drive circuit 23 and the aperture mechanism control circuit 25 are controlled based on the control signal from the camera body 1.

On the other hand, in the camera body 1, the subject light incident through the lens 22 of the lens barrel 2 is received by a charge-coupled device (CCD) 3, which is a solid-state image sensor. CCD
Reference numeral 3 denotes a horizontal transfer pulse and a vertical transfer pulse supplied by the CCD drive circuit 4, and converts the incident subject light into RGB electric signals synchronized with these transfer pulses.

The RGB electric signals output from the CCD 3 are sampled and gain-adjusted in an amplification and A / D conversion circuit 5, and further converted to, for example, a 10-bit digital signal. Next, the RGB electrical signals converted into digital signals are input to the image processing device 6.

In the image processing device 6, the 10-bit data of the digital signal is subjected to an interpolation process.
Image processing such as black level adjustment and gamma correction is performed. If necessary, JPEG (Joint Photographic Exper
t Group) and compressed. The JPEG-compressed image data is stored in the memory 7.

The image-processed digital image signal before compression or JPEG-compressed image data is read out from the memory 7, and the digital image signal decompressed by the image processing device 6 is converted into a D / A conversion circuit. 8 is converted to an analog value.

The analog image signal converted into the analog value is supplied to the LCD display element 10 by the LCD drive circuit 9.
Will be displayed. The LCD display element 10 is illuminated from the back by a backlight unit 11 driven by an inverter 12 and configured by a cold cathode tube or the like.

The LCD display element 10 functions as an electronic finder in the present invention. The electronic viewfinder may be configured so that the display area is reduced and viewed through an eyepiece, or may be configured as a relatively large LCD display area so that a subject image directly displayed on the display area can be directly observed. It is possible.

Here, the image processing device 6 is constituted by a digital signal processor (DSP) as an embodiment. The transfer of signals between the image processing device 6 and the microprocessor 21 of the lens barrel 2 is controlled by the camera control microprocessor 13.

The camera body 1 has a release button, a switch for switching between auto focus and manual focus, a command dial for setting the aperture, an exposure mode setting button, an aperture control button, etc., which are not shown in FIG. Have. Therefore, these are collectively shown as a camera operation unit 14 in FIG.

A command, a changeover switch signal, and the like input by the camera operation unit 14 are input to the camera control microprocessor 13. The camera control microprocessor 13 controls the state of the photographing lens 22 and the CCD 3
And the like, the state of the subject light incident thereon is detected through the microprocessor 21 of the lens barrel 2 and the image processing device 6.

Therefore, the camera microprocessor 13 sends the detected data to the microprocessor of the lens barrel 2 through the image processing device 6 so that the detected data corresponds to a command set by the camera operation unit 14, a switch signal, and the like. 21 and the image processing device 6 are feedback-controlled.

FIG. 2 is an external view of a camera with an electronic viewfinder according to an embodiment of the present invention having the configuration shown in FIG. 1, particularly a view of the camera as viewed from above. In FIG. 2, a lens barrel 2 is mounted on a camera body 1 in a replaceable manner by a mount.

As the camera operation unit 14 shown in FIG. 1, a release button 31, a command dial 3 for setting an aperture, etc.
2. a focus mode changeover switch 33 for switching between auto focus and manual focus, an exposure mode setting button 34 for switching the exposure mode between program auto, aperture priority auto, shutter priority auto, and the like;
An aperture control button 35 is provided.

Further, an eyepiece 36 is provided, and constitutes an electronic finder integrally with the LCD display element 10 of FIG. Therefore, the LC of FIG.
The subject image displayed on the D display element 10 can be confirmed.

Further, the lens barrel 2 is provided with a lens distance ring 41 for enabling manual focusing.

In the camera with the electronic finder according to the present invention, the CC
A technique is adopted in which high-frequency components of the subject image received at D3 are integrated at a plurality of focal positions, and the maximum point of the integrated value is set as a focus position. This autofocus operation is known as a so-called hill-climbing method.

The arithmetic processing for the auto focus control is performed in the microprocessor 13 of the camera body 1. That is, when the autofocus mode is selected by the camera operation unit 14, first, the high frequency components of the light image at a certain lens position are integrated.

Next, the lens control microprocessor 2
According to 1, the lens driving means 23 controls the photographing lens 22 to drive in infinite or close directions. At this time, the high frequency component is integrated again.

The microprocessor 13 of the camera body 1 feedback-controls the lens control microprocessor 21 and compares it with the previous integrated value. If the value is large, the value is in the same direction. If the value is small, the value is reversed. The lens is driven in the direction of, the peak of the integrated value is found, and the lens is stopped.

In the manual focus, the photographer operates the distance ring 41 of the lens barrel 2 to focus while looking at the viewfinder.

On the other hand, the exposure is adjusted by the aperture value of the lens and the speed of the mechanical shutter in the case of a camera using a silver halide film. CCD as an image sensor
In the case of an electronic still camera that converts a light image of a subject into an electric signal according to 3, in general, C is used without using a mechanical shutter.
The shutter speed is changed by controlling the accumulation time of the CD. For example, the longer the sweeping period of the CCD and the shorter the accumulation time, the higher the shutter speed.

Here, as the aperture value for the lens 22 is increased by the aperture mechanism 24, the range in which the lens 22 is in focus, that is,
It is known that the depth of field increases. In a general silver halide film camera using an optical finder without an electronic finder, the lens 22 is normally opened.

This is to make the subject light image of the optical viewfinder brighter and to easily confirm the subject light image at the time of photographing. Then, control is performed such that the aperture value is narrowed down to the set aperture value instantaneously only during shooting.

Therefore, in such a camera that is controlled so that the aperture of the lens 22 is stopped down to the set aperture value instantaneously only at the time of photographing, the stop lever is operated to check the depth of field. It is necessary to do. In this case, the subject light image of the finder becomes dark corresponding to the stop-down.

In view of the above, the present invention is characterized in that the brightness (luminance) of the finder light image is maintained by using a finder using a display element such as an LCD, that is, an electronic finder.

For this reason, according to the present invention, in the camera using the electronic finder, when the aperture value of the lens 22 is narrowed down, the accumulation time of the CCD 3 is extended so that the accumulation amount of the CCD 3 is kept constant, and the finder light is emitted. The brightness (luminance) of the image can be maintained.

That is, as shown in FIG. 3, as a characteristic of the CCD 3, the electric shutter speed can be changed by controlling the discharge period and making the accumulation time variable. Therefore, when the aperture value of the lens 22 is narrowed down, by extending the accumulation time of the CCD 3, the shutter speed can be reduced and the accumulation amount of the CCD 3 can be kept constant. Thereby, the brightness (brightness) of the finder light image can be maintained.

Alternatively, by increasing the output gain of the CCD 3, the brightness (luminance) of the finder light image can be maintained. In this case, when the aperture value of the lens 22 is increased and the accumulation time is constant, the output level is reduced. Therefore, in this case, CCD3
Is controlled to increase the output gain. Again, C
Since the output level of the CD 3 can be kept constant, the brightness (luminance) of the finder light image can be maintained.

On the other hand, consider a case where the focus is accurately adjusted by manual focus. At this time, it is preferable to set the aperture of the lens 22 to an open value so that the depth of field of the finder light image becomes shallow regardless of the constant brightness.

When photographing with auto focus, it is better to keep the lens 22 down to an aperture value that is set so that the depth of field can always be confirmed. It is preferable because it is possible.

Therefore, in the present invention, when the auto focus is selected, the aperture of the lens 22 is always controlled so as to have the set aperture value.
In this case, the aperture of the lens 22 is controlled to the set value,
As described above, since the brightness of the electronic viewfinder is kept constant according to the present invention, it is easy to confirm the subject light image.

When the manual focus is selected, the aperture is kept open until immediately before the shooting operation, and the aperture of the lens 22 is stopped down to the aperture value set at the time of shooting.

In order to realize the features of the present invention, the aperture of the lens 22 is controlled by an aperture mechanism 24 as follows as an embodiment. In FIG. 2, the aperture mode setting button 34 sets an aperture priority auto mode. At this time, by operating the command dial 32, the aperture setting value of the lens changes.

The aperture value set by the command dial 32 is transmitted to the lens control microprocessor 21 by the microprocessor 13 in FIG. Next, the microprocessor 21 controls an aperture driving circuit 25 composed of a stepping motor or the like to drive the aperture mechanism 24.

On the other hand, appropriate shutter speed data is calculated from the luminance level obtained by the CCD 3, and
The storage time of the CD is controlled. When the shutter priority auto mode is selected, the shutter speed is set by the command dial 32. Then, an appropriate aperture value is calculated from the luminance level obtained by the CCD 3. The aperture driving unit 25 controls the calculated aperture value.

When the program auto mode is selected, an appropriate shutter speed and aperture value are calculated from the luminance level obtained by the CCD 3, and the accumulation time and the aperture value are controlled based on the calculated values.

At this time, when the command dial is operated,
The combination of shutter speed and aperture value changes.
Here, when the auto focus mode is selected, the aperture value and the shutter speed are controlled as described above, but when the manual focus mode is selected, the aperture is actually controlled to be open. .

At this time, the shutter speed, that is, the CCD, is determined according to the difference between the aperture value set by the command dial or the aperture value obtained by calculation and the aperture value at the open position.
The accumulation time of No. 3 is controlled to be short.

Then, in response to the release operation, shooting is performed with the actual aperture value and shutter speed.

FIG. 4 is a flowchart of the operation corresponding to the above description. The flow of operation from photometry (step S101) to completion of shooting (step S115) is shown. In the present invention, a release determination process (step S115)
The process up to 111) is defined as framing, and the subsequent processing is defined as photographing.

In FIG. 4, first, photometry is performed (step S101). The output signal of the CCD 3 is used as the photometric signal. Next, the exposure mode is determined (step S
102, S103). If it is determined that the mode is the aperture priority auto mode (step S102: YES), an appropriate shutter speed is calculated from the set aperture value (step S104).

If it is determined in step S102 that the mode is not the aperture priority auto mode, it is determined whether or not the shutter priority auto mode is set (step S103). If it is determined that the current mode is the shutter priority auto mode (step S103: YES), an appropriate aperture value is calculated from the set shutter speed (step S105).

If it is determined in step 103 that the mode is not the shutter priority auto mode, it is determined that the program auto mode is set, and the appropriate shutter speed and aperture value are set.
It is calculated (step S106).

Steps S104, S105, S106
When the shutter speed and the aperture value are determined, it is next determined whether or not the camera is in the auto focus mode (step S107).

If it is determined that the mode is the auto focus mode (step S107: YES), the aperture value is narrowed down to the set or calculated aperture value (step S108).

At this time, when the aperture value of the lens 22 is reduced, the electronic finder becomes dark. Therefore, according to the present invention, in order to keep the brightness of the electronic viewfinder constant, the accumulation time of the CCD 3 is extended to increase the C time.
The brightness (brightness) of the finder light image is maintained while the accumulated amount of CD3 is kept constant.

That is, as described with reference to FIG.
As a characteristic of the CD 3, the electric shutter speed can be changed by controlling the sweeping period and making the accumulation time variable.

Therefore, when the aperture value of the lens 22 is narrowed down, by extending the accumulation time of the CCD 3, the shutter speed can be reduced and the accumulation amount of the CCD 3 can be made constant. Thereby, the brightness (brightness) of the finder light image can be maintained. Alternatively, the brightness (luminance) of the finder light image can be maintained by increasing the output gain of the CCD 3.

On the other hand, if it is determined that the mode is the manual focus mode (step 107: NO), the aperture is controlled to be open (step S109). Next, the shutter speed is shifted to the high speed side by the set speed or the number of steps corresponding to the difference between the calculated aperture value and the open aperture value (step S).
110).

Following the processing in step S108 or S110, it is determined whether or not a release operation has been performed (step S111). If the release operation has not been performed, the process returns to step S101. If the release operation has been performed, it is determined whether the setting is the auto focus mode (step S112).

If it is determined that the mode is the auto focus mode (step S112: YES), the photographing is performed as it is (step S115).

If it is determined that the mode is the manual focus mode (step S112: NO), the aperture value is set or reduced to the calculated aperture value (step S113). further,
The shutter speed is reset to the set or calculated value (step S114), and the process proceeds to step 115 to perform photographing (step S115). After the photographing is completed, the process returns to step S101.

In manual focus, the setting or control aperture value differs between before and during shooting except when the aperture value is other than open. Therefore, when shooting information such as the aperture value is displayed on the LCD display element 10, a warning display is set. It is preferable to carry out.

As described above, in the present invention, when manual focus is selected (step S112: NO),
The aperture value of the lens is open before photographing regardless of the setting or control aperture value.

At this time, in order to confirm the actual depth of field, when the aperture control button 35 shown in FIG. 2 is pressed, the microprocessor 13 is set only during that time, or is switched to the control aperture value and the shutter speed. In the camera body 1, the output gain of the CCD 3 and the aperture mechanism 25 through the microprocessor 21 of the lens barrel 2.
Control.

As a result, the brightness of the electronic viewfinder 10 can be kept constant without changing, and the light image of the object under actual shooting conditions can be confirmed.

On the other hand, when auto focus is selected, the depth of field can be checked, but the focus state cannot be checked accurately. At this time, when the iris control button 35 is pressed, the iris is opened and the shutter speed is controlled to the higher speed side, so that the focus can be accurately confirmed without changing the brightness of the electronic finder 10. Becomes If the distance is measured again in this state, accurate focusing can be achieved.

When the release operation is performed while the aperture control button 35 is pressed, the photographing operation is performed at the aperture value and shutter speed at the time of manual focus, and at the aperture value or shutter speed set after the release operation at the time of autofocus. Is performed.

FIG. 5 is a block diagram of a second embodiment of the present invention. In the first embodiment shown in FIG.
The digital image signal obtained by D3 is stored as a photographed image, and this is observed with an electronic finder.

On the other hand, in the second embodiment, the image can be further stored on a silver halide film as a photographed image.
It is a camera with an electronic viewfinder. The difference from the configuration diagram of FIG. 1 is that the subject light that has passed through the photographing lens 22 is split by a pair of half mirrors 15 and enters the CCD 3 and the silver halide film 16.

The other configuration is the same as that of the embodiment shown in FIG. 1, and further description is omitted.

Although not shown in the embodiments of FIGS. 1 and 5, it is also possible to output image data to be written in the memory 17 to the outside through a connector. Thus, the image data output to the outside can be subjected to image processing by a personal computer or the like.

According to the present invention, the subject is confirmed by the aperture value set or calculated at the time of auto focus. Also, the aperture is set to open only when the aperture control button is pressed, but if the user wants to keep the aperture open, the user can lock the aperture while pressing the aperture control button, for example. Is also possible.

[0083]

As described above according to the embodiment,
According to the present invention, since the lens is stopped down to the aperture value set or calculated in the auto focus mode, the subject can be confirmed in a state closer to the shooting result, including the depth of field.

At the same time, there is no need to stop down the aperture at the time of photographing, so that the effect of reducing the time lag from when the shutter button is pressed to when the image is actually photographed can be obtained.

On the other hand, in the manual focus mode, the aperture is open and the depth of field is the shallowest, so that accurate focus adjustment is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment showing respective configurations of a camera body with an electronic viewfinder and a lens barrel according to the present invention.

FIG. 2 is an external view of a camera with an electronic viewfinder according to the present invention;
It is a figure which especially shows the upper surface.

FIG. 3 is a diagram illustrating shutter speed control based on the accumulation time of a CCD 3.

FIG. 4 is a flowchart showing a photographing operation of the camera with an electronic viewfinder of the present invention.

FIG. 5 is a block diagram of a second embodiment showing respective configurations of a camera body with an electronic viewfinder and a lens barrel according to the present invention.

[Explanation of symbols]

Reference Signs List 1 camera body with electronic finder 2 lens barrel 3 charge-coupled device (CCD) 4 CCD drive circuit 5 amplification and A / D conversion circuit 6 image processing device 7 memory 8 D / A conversion circuit 9 LCD drive circuit 10 LCD display element (electronic 11) Backlight unit 12 Inverter 13 Camera control microprocessor 14 Camera operating unit 15 Half mirror 16 Silver halide film 21 Lens cylinder side microprocessor 22 Photo lens 23 Lens drive circuit 24 Aperture mechanism 25 Aperture mechanism control circuit 31 Release button 32 Command dial 33 Focus mode switch 34 Exposure mode setting button 35 Aperture control button 36 Eyepiece 41 Lens distance ring

Claims (14)

[Claims] 1. An electronic image sensor for outputting an image signal of a subject image, an electronic finder for displaying an image signal of the subject image output from the electronic image sensor, and control means for performing lens aperture control and auto focus control The control means performs lens aperture control so as to remain set at a predetermined aperture value during framing and shooting during autofocus control, and outputs from the electronic image sensor. A camera with an electronic finder, wherein the level of an image signal of a subject image to be displayed is controlled so as to change the brightness of the display of the electronic finder. 2. The apparatus according to claim 1, wherein the control means controls the lens aperture so that the aperture value is adjusted to an open aperture during framing and to the predetermined aperture value during photographing during manual focus control. A camera with an electronic viewfinder. 3. The electronic imaging device according to claim 1, wherein the electronic imaging device is a charge-coupled device, and the level of an image signal of a subject image output from the charge-coupled device is controlled.
A camera with an electronic viewfinder, which is performed by controlling an output gain of the charge-coupled device or an accumulation time of the charge-coupled device. 4. The electronic device according to claim 1, wherein the control unit sets an image signal level of a subject image output from the electronic image pickup device, a display brightness of the electronic finder, and a lens aperture to be open. A camera with an electronic finder, characterized in that the camera is controlled so as to be constant when the aperture value is set to a predetermined value. 5. The brightness of a display of the electronic finder controlled to be constant, the brightness being equal to the brightness of a level of an image signal of a subject image output from the electronic image pickup device when the lens aperture is opened. A camera with an electronic viewfinder. 6. A camera with an electronic finder according to claim 1, wherein said electronic image pickup device is a charge storage device, and said electronic finder comprises a liquid crystal display device. 7. The image processing apparatus according to claim 1, further comprising: a memory for storing an image signal of a subject image output from said electronic image pickup device; A camera with an electronic viewfinder, wherein a signal is read out and can be reproduced and displayed on the electronic viewfinder. 8. A camera with an electronic viewfinder according to claim 7, further comprising a connector for outputting an image signal of a subject image stored in said memory to the outside. 9. The camera with an electronic viewfinder according to claim 1, wherein the predetermined aperture value is reset to an open aperture by a predetermined operation input during framing. 10. The camera with an electronic viewfinder according to claim 2, wherein the aperture is reset to a predetermined aperture value by a predetermined operation input during framing. 11. The camera with an electronic viewfinder according to claim 9, wherein the aperture value is reset and the state can be arbitrarily fixed by the predetermined operation input. 12. The camera with an electronic viewfinder according to claim 9, further comprising a warning unit, wherein when the aperture is reset to the full aperture, the warning unit displays a warning. 13. The camera with an electronic viewfinder according to claim 9, further comprising a warning means, wherein said warning means displays a warning when said predetermined operation input is not made during photographing. 14. A camera with an electronic viewfinder according to claim 12, wherein a warning by said warning means is displayed in said electronic viewfinder.