JP2005020397A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera capable of executing an automatic focusing operation reasonably even during an electronic preview operation during electronic preview capable of confirming the effects on images of a shutter and a diaphragm, etc., as the images before photographing. <P>SOLUTION: When an electronic preview switch 28 is turned on, a CPU 21 executes photometry, computes an exposure value and performs an AE locking processing. A mirror driving device 22 is controlled and a main mirror 7 and a sub mirror 12 are raised. In the case of turning a focus switch 27 on, the mirrors are restored to reflection positions and a range finding arithmetic device 20 calculates a defocus amount with an object image based on data from an AF sensor 19. The CPU 21 drives an AF motor 4 through a CPU 6 and brings a focus lens 2 to a focus position in the case that the lens is not at the focus position. In the case that a focusing operation is canceled, the electronic preview is continued. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital camera, and more particularly to a digital single-lens reflex camera having a preview function for confirming an image before photographing and suitable for performing focus adjustment during a preview operation.
[0002]
[Prior art]
Conventional digital single-lens reflex cameras cannot see changes in captured images due to differences in aperture, shutter time, etc. before shooting. When confirming a photographed image, the photographed image is reproduced on the display device after photographing. If the reproduced image is different from the photographer's intention, the image can be discarded, and the image can be taken again by changing the shutter speed, the aperture, and the like.
Further, Patent Document 1 has been proposed as an image that can be confirmed even while a digital single-lens reflex camera is photographing (while the shutter is off).
Before shooting, the subject image from the taking lens is confirmed with the optical viewfinder, and while the shutter is released, the subject image read into the image sensor is displayed on the LDC installed at a position where it can be seen with the optical viewfinder. The LCD image is switched so that it can be observed with the same optical viewfinder. Although the captured image can be confirmed with an optical finder without any breaks, the captured image cannot be confirmed before shooting.
[Patent Document 1]
Japanese Patent Laid-Open No. 10-294888
[Problems to be solved by the invention]
Therefore, the applicant of the present application has proposed an electronic preview function that allows an image to be confirmed before shooting under the same exposure conditions as during shooting (Japanese Patent Application No. 2003-176834). If this function is used, it is extremely effective for capturing an intended image, and it is possible to check the background blur due to a difference in aperture value and the image flow due to a difference in exposure time before shooting.
The preview function operates to move the reflecting mirror to the retracted position, open the light shielding shutter, and continuously read out image signals from the image sensor and display them continuously on the display device. At this time, by controlling to the same aperture value and exposure time (electronic shutter) as at the time of photographing, it becomes possible to photograph after confirming the effect.
Here, it is necessary to correct the focus when the subject moves during the electronic preview or the position where the camera is held is moved back and forth. However, in the electronic preview state, it is not possible to use the autofocus function for measuring the distance by reflecting the light beam that has passed through the photographing lens with a mirror and guiding it to the distance measuring sensor.
[0004]
An object of the present invention is to have an electronic preview function that can confirm an effect on an image such as a shutter and an aperture as an image before photographing, and an operation member that gives an autofocus operation instruction, and the autofocus instruction is given during the electronic preview operation. In this case, the main reflection mirror is returned to the reflection position, the auto focus operation is performed, and after the auto focus operation is completed, the reflection mirror is moved to the retracted position and the electronic preview operation is continued. It is an object of the present invention to provide a digital camera capable of performing an autofocus operation without any problem.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 includes an imaging device, a display device that displays image data exposed to the imaging device, an optical viewfinder for confirming a subject image at the time of photographing, A reflection mirror movable between a reflection position for reflecting and guiding the subject image to the optical viewfinder and a retraction position for retracting the subject light to the image sensor, and the mode switch is operated; A digital camera having an electronic preview mode for detecting and driving the reflecting mirror to the retracted position and displaying on the display device image data exposed to the imaging device under a predetermined exposure condition, Further includes a focus switch, focus adjusting means for adjusting a focus position of the subject image, and the focus during the electronic preview mode. If the switch is turned ON, and having a control means for focusing by the focusing means the reflection mirror after driving to the reflection position.
According to a second aspect of the present invention, in the digital camera according to the first aspect, when the focus adjustment operation by the focus adjustment unit is finished, the control unit drives the reflecting mirror to the retracted position and shifts to the electronic preview mode. It is characterized by having.
According to a third aspect of the present invention, in the digital camera according to the first or second aspect, a photometric device that is effective when the reflecting mirror is in a reflection position and a photometric operation during the focus adjusting operation by the focus adjusting means are performed. And a control means.
[0006]
[Action]
According to the above configuration, even when the focus is shifted due to the movement of the subject during the electronic preview, the focusing operation can be performed with a natural operation flow, and an image that matches the shooting intention of the photographer can be obtained. Can do.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a digital camera according to the present invention, and FIG. 2 is a cross-sectional view for explaining the layout of the camera body mechanism. In both figures, only the part directly related to the present invention is shown. Are listed.
The digital single-lens reflex camera 1 is composed of a camera body 1a and an interchangeable lens 1b. When the interchangeable lens 1b is attached to the camera body 1a, the CPU 6 in the interchangeable lens 1b and the CPU 21 in the camera body 1a can communicate with each other.
The CPU 6 controls the driving of the focus lens 2 and the diaphragm 3 by the AF motor 4 and the diaphragm motor 5, respectively.
[0008]
Reflected light from a subject (not shown) passes through the interchangeable lens 1b and is reflected by the main mirror 7 to form an image on the focusing screen 34 (see FIG. 2). The subject image on the focusing screen 34 is guided to the eyepiece 32 by the pentaprism 8 and converted to an erect image. Part of the subject image that has passed through the pentaprism 8 is guided to the photometric sensor 9. The subject image incident on the optical viewfinder 10 passes through the eyepiece shutter 11 and enters the eyes of a photographer (not shown). The photographer can observe an erecting virtual image of the subject by the eyepiece 32 (see FIG. 2) of the optical viewfinder 10.
[0009]
On the other hand, part of the subject light incident on the main mirror 7 reaches the sub mirror 12, is guided to the lower part by the sub mirror 12, and enters the AF sensor 19 in the AF module (see FIG. 2). The distance measuring device 20 calculates the defocus amount with respect to the subject image based on the data from the AF sensor 19. The CPU 21 derives lens drive data up to the in-focus position from the determined defocus amount, and transfers this data to the CPU 6. The CPU 6 drives and controls the AF motor 4 according to the transfer data, and brings the focus lens 2 to the in-focus position.
[0010]
The photometric value from the photometric sensor 9 is input to the exposure calculation device 25, and the exposure value is calculated by the exposure calculation device 25. The CPU 21 determines the aperture value so as to obtain an appropriate exposure amount based on the exposure value. This aperture value data is transferred to the CPU 6, and the CPU 6 drives and controls the aperture motor 5 so that the aperture 3 becomes the determined aperture value.
In normal shooting, when a shooting signal is input from the release switch 26, the CPU 21 performs AE lock processing, turns on the image sensor 13, and controls the mirror driving device 22. The mirror driving device 22 drives the mirror up motor 23 to retract the main mirror 7 and the sub mirror 12 arranged on the back side of the main mirror to the upper part of the mirror box.
[0011]
Then, the shutter 33 (see FIG. 2) is opened, and the subject light is imaged on the image sensor 13. The image sensor control device 24 controls the readout of the charge of the image data imaged on the image sensor 13 by setting the timing (shutter speed) and gain (ISO sensitivity) corresponding to proper exposure under the control of the CPU 21. The image pickup device 13 is a progressive type CCD, and the charges received by the light receiving window are transferred to the light-shielding portion after all the pixels are transferred simultaneously, so that a relatively good image can be obtained even when the shutter 33 is opened. Is obtained. Image data read from the image sensor 13 is subjected to predetermined processing by the image processing device 14 and transferred to the storage device 17. The storage device 17 temporarily stores this image and records it on the recording medium 18 in a predetermined file format.
The image processed by the image processing device 14 is also sent to the display data processing device 15, converted into a display format, and displayed on the display device (LCD) 16.
[0012]
The photographer can confirm the photographed image and delete it if the image is not satisfactory. Deletion can be performed by operating various setting switches 31. When the CPU 21 receives a delete instruction signal from the various setting switches 31, the CPU 21 deletes the captured image displayed on the display device 16 from the recording medium 18.
When reading from the image sensor 13 is performed, the shutter 33 is closed and the main mirror 7 and the sub mirror 12 are returned to their original positions.
[0013]
In photographing using the electronic preview function, when a preview signal is input from the electronic preview switch 28, the CPU 21 controls the eyepiece shutter drive motor 35 to close the eyepiece shutter 11. After that, exposure calculation is performed by the photometric sensor 9 and the exposure calculation device 25 in the same manner as in normal shooting, and the CPU 21 performs AE lock processing of the exposure value, turns on the image sensor 13, and controls the mirror drive device 22 to perform main processing. The mirror 7 and the sub mirror 12 are retracted, and the shutter 33 is opened.
The CPU 21 controls the image sensor control device 24 to set timing (shutter speed) and gain (ISO sensitivity).
[0014]
Then, control is performed to read out the charge of the imaged image data from the image sensor 13. Image data read from the image sensor 13 is subjected to predetermined processing by the image processing device 14, sent to the display data processing device 15, converted into a display format, and displayed on the display device (LCD) 16. Next, various settings are read and the control value is calculated. Unless the release is performed and the preview is not turned off, this display operation is repeated, for example, three times per second.
[0015]
The electronic preview function allows the photographer to check in advance which shutter speed is the desired image because the shutter speed can be actually changed in order before the image is taken and the images at the respective shutter speeds can be observed. . It is also possible to reduce the aperture in order, confirm the depth of focus of the image, and select the desired aperture. In addition, the white balance, exposure correction amount, program shift amount, and amplification factor can be confirmed in the same manner.
When a release switch signal is input in the electronic preview state, timing and gain are set, image data is read from the image sensor 13, subjected to predetermined processing by the image processing device 14, and then an image is recorded on the recording medium 18 via the storage device 17. Store.
[0016]
The focus switch 27 sends a focus signal to the CPU 21 when the focus button is pressed. When pressed during the electronic preview, the CPU 21 controls the mirror driving device 22 to drive the mirror up motor 23 to return the main mirror 7 and the sub mirror 12, perform the focusing operation, and then again to the main The mirror 7 and the sub mirror 12 are driven to the retracted position. In the focusing operation, the CPU 21 obtains distance data by the distance calculation device 20 based on the distance measurement data from the AF sensor 19 obtained by returning the main mirror 7 and the sub mirror 12, and calculates the defocus amount. Then, the AF motor 4 is driven via the CPU 6 to bring the focus lens 2 to the in-focus position.
The command dial 30 is a so-called electronic dial for selecting various settings in combination with an exposure correction setting button 42, an ISO setting button 43, and a WB setting button 44, which will be described later.
[0017]
FIG. 3 is an external view for explaining the arrangement of switch buttons of the digital single-lens reflex camera of FIG.
An LED panel 46 for displaying camera information and a release button 35 are arranged on the upper right surface of the digital single-lens reflex camera 1, and a command dial 45 is provided on the front side thereof. An exposure correction setting button 42, an ISO setting button 43, and a WB setting button 44 are arranged on the upper left surface. By pressing the exposure correction setting button 42 and operating the command dial 45, the EV value can be adjusted to ± 0.3, ± 0.6, ± 1.0, ± 1.5,. By pressing the ISO setting button 43 and operating the command dial 45, for example, ISO 50, 100, 200, 400, 800,... Can be adjusted. By pressing the WB setting button 44 and operating the command dial 45, it can be adjusted to AUTO, strobe light, fluorescent light, 8200K,.
[0018]
A display device (LCD) 39 is provided near the center of the back surface of the digital single-lens reflex camera 1, and an optical viewfinder 40 is disposed on the display device (LCD) 39.
On the right side of the display device (LCD) 39, an electronic preview button 37 is arranged. Further, a focus button 36 is arranged on the upper right, and the focusing operation can be performed even during the electronic preview operation.
Various setting buttons 41 are arranged on the left side of a display device (LCD) 39.
[0019]
FIG. 4 is a flowchart for explaining the photographing operation of the digital single lens reflex camera according to the present invention.
Hereinafter, a flow of operations of shooting using the electronic preview function capable of performing a focusing operation according to a shooting sequence and normal shooting will be described.
The photographer can set the exposure mode using various setting buttons 41. Aperture priority, shutter priority, program, manual, etc. modes. In the aperture priority mode and the shutter priority mode, the aperture and shutter speed can be selected manually, and when the aperture and shutter speed are changed during electronic preview, the changed captured image can be observed. In the program mode, when the electronic preview is in progress, the program shifts in accordance with the locked AE value. In the manual mode, a captured image reflecting the set shutter speed and aperture can be previewed.
[0020]
The CPU 21 first reads the exposure mode (step (hereinafter referred to as “S”) 001) and determines whether or not the electronic preview button has been pressed (S002).
When the electronic preview button 28 is pressed, a process for closing the eyepiece shutter 11 is performed (S003). Then, after performing photometric control and exposure calculation (S004, S005), AE lock processing is performed (S006).
Next, image sensor ON processing, mirror up processing, and shutter opening processing are performed (S007 to S009).
[0021]
Next, it is determined whether or not the focus button 36 has been pressed (S010).
When the focus button 36 is pressed, the CPU 21 controls the mirror driving device 22 and drives the mirror up motor 23 to return the mirror to the original position (reflection position) as shown in FIG. Then, the aperture motor 5 is controlled to move the aperture 3 to the open position (S011). Then, AF control is performed (S012).
FIG. 5 shows a flowchart of AF control.
The CPU 21 calculates distance data using the distance calculation device 20 based on the data measured by the AF sensor 19 (S101). A focus shift amount, that is, a defocus amount is calculated from the distance data and the current lens position (S102), and it is determined whether or not the current lens position is in a focus position (S103). If it is in the in-focus position, the AF control is terminated. If not in the in-focus position, the AF motor 4 is driven via the CPU 6 to bring the focus lens 2 to the in-focus position (S104).
[0022]
After AF control, photometric control is performed and AE lock processing is performed, and then an exposure value is calculated by the exposure calculation device 25 based on the photometric value (S013, S014, S015). After the CPU 21 performs a focusing operation and obtains an exposure value, the CPU 21 controls the mirror driving device 22 and drives the mirror up motor 23 to return the main mirror 7 and the sub mirror 12 to the retracted position (S016). Then, it is determined whether or not the focus button 36 has been released (S017). If the focus SW is still on, the above AF control and photometry control are repeated. When the focus SW is turned off, under the control of the CPU 21, the imaging control device 24 sets timing (shutter speed) and gain (ISO sensitivity) for the measured appropriate exposure (S018).
[0023]
On the other hand, if the focus SW is not on in S010, the timing and gain for the exposure value calculated in S005 are set (S018).
Next, exposure control of the subject image on the image sensor 13 is performed (S019), the image data is transferred to the image processing device (S020), and the display data processing device 15 performs display processing on the display device 16 (S021). Next, various settings (parameters) are read (S022). For example, shutter speed, aperture value, exposure amount correction, ISO sensitivity, white balance, etc. are read. If the photographer changes the parameter in this preview state, the changed value is read and the calculation is performed. As an example of parameter change, if the shutter speed is in the shutter speed priority mode and the shutter speed is 1/60 seconds and the aperture is 8, the aperture value becomes 5.6 if the shutter speed is changed to 1/125 seconds.
[0024]
Next, it is determined whether or not the release is turned on (S023). If the release is on, shooting is performed in S037 to S041. If the release is off, it is next determined whether or not the electronic preview is still on (S024). When the electronic preview is turned off, the CPU 21 lowers the main mirror 7 and the sub mirror 12 to return them to the original positions (S025), and returns to the exposure mode reading (S001) start position.
If the electronic preview is on, the process proceeds to S018. Unless the release is off and the electronic preview is not canceled, the loop of S018 to S24 is repeatedly executed.
As described above, since the image sensor is a progressive method, a new charge is not added during charge transfer, and the charge of each image can be transferred without error. Therefore, during the electronic preview, the same image as the captured image can be observed, and the shooting conditions can be changed.
[0025]
If the electronic preview button is not pressed in S002, the CPU 21 performs a process of closing the eyepiece shutter 11 (S026). Then, after performing photometric control and exposure calculation (S027, S028), it is determined whether or not the release is turned on (S029). If the release is off, the process proceeds to determining whether the focus SW is on (S030). If the focus SW is off, the process returns to S001 to read the exposure mode. On the other hand, if the focus SW is on, the CPU 21 calculates the defocus amount based on the distance data of the distance calculation device 20 obtained by calculation based on the distance measurement data from the AF sensor 19 and the current lens position, via the CPU 6. A focusing operation of the focus lens is performed (S031). As long as the focus SW is pressed, the AF control in S031 is repeated. When the focus SW is turned off, the exposure mode reading in S001 is resumed.
[0026]
When the release button 35 is pressed in S029, an AE lock process, an image sensor on process, a mirror up process, and a shutter open process are performed (S033 to S036). Then, after exposure control, the shutter is closed and data transfer is performed, and then a recording process is performed by the recording device 17, the photographed image is stored in the recording medium 18, and the mirror is returned (S037 to S041).
[0027]
【The invention's effect】
As described above, according to the present invention, the electronic preview operation is performed in which the effects such as the shutter speed and the aperture value set with the intention of photographing before photographing can be confirmed as an image, and the focus adjustment is necessary during the electronic preview operation. In such a case, it is possible to realize a digital camera capable of performing an autofocus operation with a natural operation flow by operating the AF instruction member.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a digital camera according to the present invention.
FIG. 2 is a cross-sectional view for explaining a layout of a camera body mechanism.
3 is an external view for explaining the arrangement of switch buttons of the digital camera of FIG. 1. FIG.
FIG. 4 is a flowchart for explaining a photographing operation of the digital camera according to the present invention.
FIG. 5 is a flowchart for explaining a distance measuring operation;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Digital single-lens reflex camera 2 Focus lens 3 Aperture 4 AF motor 5 Aperture motor 6,21 CPU
7 Main mirror 8 Penta prism 9 Photometric sensor 10 Optical viewfinder 11 Eyepiece shutter 12 Sub mirror 13 Image sensor 14 Image processing device 15 Display data processing device 16 Display device (LCD)
Reference Signs List 17 Storage device 18 Recording medium 19 AF sensor 20 Distance calculation device 22 Mirror drive device 23 Mirror up motor 24 Image sensor control device 25 Exposure calculation device 26 Release switch 27 Focus switch 28 Electronic preview switch 30 Command dial (electronic dial)
31 Various setting switches

Claims (3)

An image sensor, a display device that displays image data exposed to the image sensor, an optical finder for confirming a subject image at the time of photographing, and a reflection position that reflects and guides the subject image to the optical finder A reflective mirror movable between a retracted position for retracting in order to guide subject light to the image sensor;
It has an electronic preview mode in which it is detected that a mode changeover switch has been operated and the reflecting mirror is driven to the retracted position, and image data exposed to the image sensor under a predetermined exposure condition is displayed on the display device. A digital camera,
The digital camera further includes:
A focus switch,
Focus adjusting means for adjusting the focus position of the subject image;
Control means for performing focus adjustment by the focus adjustment means after driving the reflection mirror to the reflection position when the focus switch is turned on during the electronic preview mode;
A digital camera comprising: The digital camera according to claim 1, wherein
A digital camera comprising control means for driving the reflecting mirror to the retracted position and shifting to the electronic preview mode when the focus adjustment operation by the focus adjustment means is completed. The digital camera according to claim 1 or 2,
A photometric device that is effective when the reflecting mirror is in the reflecting position;
Control means for performing photometric operation during focus adjustment operation by the focus adjustment means;
A digital camera comprising:

Images