JP2003149536A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera which does not require the strict positioning of film or an imaging device and a screen mat and which prevents the deterioration of a manual photographic image caused by the relative positional deviation of the film or the imaging device with respect to the screen mat. SOLUTION: In this single lens reflex type digital camera, the deviation of the attaching position L2 of the screen mat 21 with reference to the position L1 of the imaging device 32 is stored in a flash memory 41 being a storage means. At the time of manual focus photographing, a focus lens 13 is positionally moved by amount equivalent to the deviation just before exposure and focused on the light receiving surface of the imaging device 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera, the position of a film or an image pickup device, and the position of a focusing plate (matt glass) for confirming the focus at the time of manual focusing provided at a position equivalent thereto. Due to the deviation of
The present invention relates to a camera in which the in-focus state on the light-receiving surface of a film or an image pickup device does not shift during manual focus shooting.

[0002]

2. Description of the Related Art A single-lens reflex digital camera with an optical viewfinder has been developed. This camera is provided with two types of focusing methods, namely, auto focus (AF) and manual focus (MF) as focusing means.

FIG. 5 and FIG. 6 show the respective operations of conventional AF photography and MF photography. At the time of AF photographing, as shown in FIG. 5, first, it is determined whether or not the first release operation is started (step S31). When the user presses the release button halfway to enter the first release operation, pre-photometry and AF focus drive are performed (steps S32, S3
3) Further, it is confirmed whether or not the first release operation is being performed (step S34), and it is determined whether or not the first release operation is being maintained and the second release operation is being performed. (Step S35). When the second release operation is entered by pressing the release button deeply, each operation of aperture drive, exposure (shooting), and recording is automatically performed sequentially (steps S36, S37, S38), and AF shooting is performed. Complete. If the fingers are released in steps S31 and S34, the process returns to step S31. If the finger is still half pressed in step S35, the process returns to step S34.

At the time of MF photographing, as shown in FIG. 6, first, the MF focus drive (that is, focus lens position adjustment) is performed so that the user presses the focus instruction button and looks into the optical finder so as to focus.
41). Next, it is determined whether or not the first release operation has been started (step S42). When the first release operation is started by pressing the release button halfway down, pre-photometry is performed (step S43), and if the photographer wants to make another adjustment, the MF focus drive is performed again (step S4).
Five). Then, it is confirmed again whether or not the first release operation is still in progress (step S46), and it is determined whether or not the second release operation is in progress while maintaining the first release operation (step S47). ). When the release button is pressed deeply while maintaining the first release operation, the second release operation is started, and the aperture drive, exposure (photographing), and recording operations are sequentially and automatically performed (step S48). , S
49, S50), MF shooting is completed. It should be noted that if the fingers are respectively released in steps S42, S44, and S46 described above, step S42 is performed.
Returning to step 41, if the finger is still half pressed in step S47, the process returns to step S46.

In this way, one digital camera is provided with two types of focus systems in the AF mode.
Normally, the in-focus position is detected within a predetermined area on the screen, so it is not possible to adjust the in-focus position to a specific subject outside the area and you want to adjust the in-focus position to a specific subject. Requires the MF mode.

For manual focusing, the optical finder is provided with a focusing screen called a screen mat for focusing confirmation.

The confirmation of focus by this screen mat is
Since the resolution is higher than that of the pixels of the liquid crystal display panel (LCD) on the back side, it has an advantage that the focusing accuracy is higher than that of focusing on the LCD display.

The operations of the single-lens reflex digital camera at the time of AF shooting and MF shooting are almost the same as those of the single-lens reflex camera using a silver salt film.

By the way, when manufacturing a single-lens reflex digital camera with an optical finder as described above, a screen mat is provided at a position optically equivalent to the position where the image pickup device is attached. Must be installed.

Since the mechanical precision of the parts is not sufficient,
Normally, their positions are adjusted during assembly. Therefore, an adjusting mechanism or a shim is required, and it takes a lot of adjustment.
Furthermore, there is a possibility that the relative position may shift with time after shipment.

If there is a displacement between the position of the image pickup device and the position of the screen mat during assembly, the captured image will not be in focus even if the screen mat is strictly focused during manual focusing. In other words, when shooting in the manual focus mode, even if the photographer looks through the optical viewfinder and focuses on the screen mat, the light-receiving surface of the image sensor is out of focus and The phenomenon of out of focus occurs.

Although the digital camera has been described, a silver salt camera using a silver salt film instead of the image pickup device is not compatible with the digital camera during manual shooting due to the relative displacement between the film surface and the screen mat which is the focusing plate. Similar problems occur.

In view of the above problems, the present invention is a camera that does not require strict positioning of the film or the image pickup device and the screen mat and eliminates the deterioration of the manually photographed image due to the relative displacement between the film or the image pickup device and the screen mat. It is intended to provide.

[0013]

According to the present invention, in a single-lens reflex camera, a photographing optical system having a moving means for moving a focus position, and an optical finder section capable of confirming a focus by the movement of the focus position. And a focusing means for manually instructing the focus position and a focus correction means for correcting the focus position set by the instructing means during manual focus photography.

Further, there is provided storage means for storing the focus correction amount by the focus correction means.

Further, the optical finder section includes a focusing plate for confirming the focus, and the focus correction amount of the focusing plate provided at a position of the planned focal plane of the photographing optical system and a position equivalent thereto. It is a value based on the amount of positional deviation.

In the present invention, the focus position is manually adjusted during manual focus photography, and the focus position confirmed by the optical finder is confirmed immediately before the start of exposure (photographing). The focus correction amount is automatically used by the CPU (or the like). As a result, at the time of manual focus shooting, the focus position is corrected even if there is a positional deviation in the planned focal plane due to the screen mat of the optical viewfinder or the shooting optical system, and the image to be shot is in focus.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a camera according to an embodiment of the present invention. In this embodiment,
A single-lens reflex digital camera having an optical finder will be described.

In the digital camera shown in FIG. 1, an optical image from a subject (not shown) enters the prism 31 through the taking lens unit 10, and a part of the optical image passes through the half mirror surface of the prism 31 and is received by the image pickup element 32. A part of the optical image is reflected by the half mirror surface of the prism 31 and passes through the optical finder section 20 and enters the eye of the photographer (not shown) through the eyepiece lens.

The photographing lens section 10 includes a zoom lens 11 capable of adjusting a zoom position and a diaphragm as a light quantity adjusting function.
12 and a focus lens 13 with adjustable focus position
And is configured.

The optical finder section 20 comprises a screen mat 21 as a focusing screen for focusing confirmation, a mirror 22 for changing the optical path, and an eyepiece lens 23.

The taking lens unit 10, the prism 31, and the image pickup device 32 constitute a taking optical system.

The photographer uses the eyepiece lens 23 during MF photography.
Focusing on the screen mat 21 by adjusting the position of the focus lens 13 by adjusting the focus instruction button (not shown) of the operation unit 42 while observing the image formed on the screen mat 21 which is the focusing screen through When the released optical image is displayed and the release button of the operation unit 42 is pressed at the set focus position, the focused image of the subject can be captured by the image sensor 32 including a CCD or the like. .

Therefore, after focusing using the optical finder, the half mirror surface of the prism 31 and the photographing element 3 can be used in order to actually obtain a photographed image.
It is necessary that the distance L1 between the light receiving surfaces of 1 and the distance L2 between the half mirror surface of the prism 31 and the image forming surface of the screen mat 21 are equal (L1 = L2).

The image pickup signal received by the image pickup device 32 and converted into an electric signal is a correlated double sampling circuit (CDS).
Circuit), an AGC circuit, an A / D conversion circuit, and the like, and is converted into a digital video signal by an image pickup circuit 33, and a CPU
Under the control of 34, it is sent to various circuits and memories through the bus line 35 for processing. Bus line 35 has A
F / AE circuit 36, DRAM 37, memory card 38,
The LCD display unit 39, the image processing circuit 40, the flash memory 41 that is a storage unit, and the CPU 3 that performs various arithmetic controls.
4 etc. are connected.

The AF / AE circuit 36 converts the contrast of the image once formed in the central portion (autofocus area) of the image pickup device 32 into an electric signal, analyzes the waveform, and analyzes the waveform with the most undulating waveform. On the basis of the brightness (luminance) of an image signal captured by the image sensor 32, an automatic focusing control circuit (AF circuit) for automatically focusing by stopping the movement of the focus lens driving motor 44. And an automatic exposure control circuit (AE circuit) that determines the aperture value.

The DRAM 37 has a memory function for temporarily storing the video signal from the image pickup circuit 33 and a memory function as a work area. The memory card 38 is used for storing captured images.

The LCD display section 39 is used for displaying an observation image at the time of photographing and reproducing the once-stored photographed image.

The image processing circuit 40 has a function of performing .gamma. Correction for recording, white balance (WB) adjustment, etc., and compresses or expands an image at the time of recording or reproducing in the memory card 38.

Flash memory 41 as storage means
Stores a camera program for causing the camera to perform various operations and correction values such as a focus correction amount.

The CPU 34 as a control means is provided with a release button, a zoom instruction button, a focus instruction button (functions only in MF), an AF / MF switching button, a registration mode button, an OK (enter) button, a power button and the like. The operation unit 42 is connected, and release control, zoom control, focus position control (functions only in MF), AF / MF switching control, registration control, decision control, power on / off based on instructions from various buttons of the operation unit 42. Performs various controls such as control.

Further, a focus motor 44 is provided as a focus moving means so that the focus lens 13 can be moved to perform a focus operation during both AF and MF, and in order to enable a zoom operation. A zoom motor 43 is provided as zoom moving means, and the zoom ratio can be changed by moving the zoom lens 11. Both the focus operation and the zoom operation are performed under the control of the CPU 34.

In focus control and zoom control,
The CPU 34 refers to the control information such as the focus lens position and the zoom lens position controlled by the drive motors 44 and 43, so that the focus adjustment and the zoom adjustment can be appropriately performed during the MF and AF. That is, during AF, the focus lens position is automatically adjusted based on the control of the CPU 34, and during MF, the photographer presses the focus instruction button of the operation unit 42 while looking into the eyepiece lens of the optical finder unit 20 and the CPU 3
The focus lens position adjustment is performed based on the control of No. 4.

In the present embodiment, during MF shooting, when the focus position is adjusted manually by the focus instruction button, the focus position confirmed to be in focus by the screen mat 21 of the optical viewfinder section 20 is the release button. Just before, for example, the second release operation, the focus correction function of the CPU 34 automatically corrects the focus correction amount stored in the flash memory 41 in advance. is there. The focus correction amount is a value corresponding to the amount of deviation between the position L1 of the image pickup device 32 and the position L2 of the screen mat 21 provided at a position equivalent thereto. As a result, during MF shooting, the focus position is corrected even if there is a positional deviation between the position L1 of the image pickup device 32 and the position L2 of the screen mat 21 provided at a position equivalent thereto, and the light receiving surface of the image pickup device 32 is corrected. A focused image will be captured.

FIG. 2 shows the M in the digital camera of FIG.
The flowchart of the imaging operation at the time of F is shown.

In the MF photographing, first, in step S1, the user presses the focus instruction button of the operation unit 42 and looks into the optical finder unit 20 while focusing on the screen mat 21 so as to focus on the screen mat 21 (that is, the focus lens). Position adjustment). Next, step S
In step 2, it is determined whether or not the first release operation has been started (step S2). When the first release operation is started by half-pressing the release button of the operation unit 42, pre-photometry is performed (step S3), and it is confirmed whether or not the first release operation is started (step S3). After S4), if the photographer wants to make another adjustment, the MF focus drive is performed again (that is, the adjustment of the focus lens position) (step S5), and the focused focus position is set on the mat. Then, after confirming again whether or not the first release operation is started (step S6), the first release operation is performed.
In step S7, it is determined whether the second release operation is started while the release operation is maintained.

When the second release operation is started by pressing the release button deeply in step S7, the focus lens for focus correction is driven (step S8).
). That is, if the focus motor 44 as the focus moving means is a step motor, by advancing or delaying some steps, the set focus position (that is, the set position of the focus lens 13 in focus on the mat). Is corrected by the focus correction amount stored in advance. Then, each operation of aperture driving and exposure (photographing) is sequentially and automatically performed (steps S9 and S10), and focus lens driving for returning the focus correction to the original focus position is performed (step S11). The recording operation is automatically performed (step S12), and the MF shooting is completed.

In the above flow, steps S2,
If you release your fingers at S4 and S6, the process returns to step S1,
If the finger is still pressed halfway in step S7, step S6
Return to.

When the flowchart of FIG. 2 of the present application is compared with the conventional flowchart of FIG. 6, steps S8 and S11 relating to focus correction in FIG. 2 are newly provided steps.

After the step S7 of the second release operation, the step S8 of driving the focus correcting focus lens is positioned as the step before the step S9 of driving the diaphragm and the step S10 of exposing (photographing). There is. This is because during MF shooting, shooting is performed while looking at the image on the screen mat 21 through the optical viewfinder section 20, so it is considerably time-wise before the exposure (shooting) operation (for example, in the first release operation maintaining state). ) When the focus correction focus lens is driven, the optical viewfinder section 20
This is because an image entering the eyes of the photographer appears to be out of focus, so that the focus position is shifted immediately before exposure so that the photographer can perform photography without noticing it. As a result, the photographer does not feel uneasy. Therefore, step S8 for driving the focus correction focus lens may be replaced with step S9 for driving the aperture, and step S8 may be set immediately before step S10 for performing exposure (photographing).

Further, the focus lens driving for returning the focus correction to the original focus position is performed in step S11 after the end of step S10 of performing the exposure in order to immediately enable another manual photographing.

Next, the registration operation by the CPU 34 for calculating the focus correction amount and storing it as the correction value in the flash memory 41 will be described.

FIG. 3 shows a flowchart of the operation for calculating and storing the focus correction amount in the digital camera of FIG. FIG. 3A shows the main flow, and FIG. 3B shows the subroutine.

As shown in FIG. 3 (a), first, the user presses a calibration mode button (not shown) of the operation unit 42 to set the CPU 34 in the calibration mode. Then, the AF mode is entered, and the image sensor 3
The contrast AF process by 2 is performed (step S2
1), focus lens position F1 automatically set by AF
Is calculated (step S22). Next, the mode is switched to the MF mode (step S23), and the MF process is performed (step S24).

The MF process is performed in the subroutine of FIG. 3 (b). That is, the user manually adjusts the focus position by operating the focus instruction button (step S241), and presses the OK button after the adjustment (step S242) to set the focus position on the screen mat. Return to the main flow of 3 (a).

Next, the focus lens position F2 set in the MF process is calculated (step S25), and the difference F1-F2 between the previously calculated F1 and F2 is calculated as a correction value (step S26). The correction value is stored in the flash memory 41 as the focus correction amount (step S27).

When the focus correction value at the time of MF image pickup is obtained and stored in this way, at the time of actual MF image pickup,
As shown in FIG. 2, fine adjustment (focus correction for positional deviation between the image pickup device 32 and the screen mat 21) is automatically performed by using the stored focus correction value immediately before the start of shooting by the release button or the like. Will be done.

Therefore, even if there is a slight misalignment between the position L1 of the image pickup device 32 and the position L2 of the screen mat 21 in the photographing optical system at the time of assembly at the factory, the focus correction value obtained in FIG. It is possible to correct this positional deviation based on the above, and receive the image in which the image pickup element surface is in focus. In addition, the user sets the calibration mode not only at the time of factory shipment but also for the occurrence of subsequent deviations such as changes with time after shipment,
By obtaining and storing a new correction value according to the flowchart of FIG. 3, it becomes possible to always perform focus correction corresponding to the positional deviation.

Although the flow chart of FIG. 3 calculates and stores the correction value in the user setting mode and uses it for the subsequent MF photographing, the correction value is calculated at the time of factory shipment as in FIG. This may be stored in the memory as an initial value (maker setting value). This is because the focus mechanism of a digital camera has individual differences based on component tolerances, assembly tolerances, etc., so focus correction values are calculated and stored in advance at the time of factory shipment, and the user's hand is troublesome during MF shooting. The focus position adjustment can be automatically performed by performing the MF shooting operation of FIG. Further, in order to enable correction of the focus position shift with time, in addition to the storage of the factory default correction value by the manufacturer, the user setting mode (calibration mode) described in parallel with FIG. ), The correction value can be calculated and stored so that the initial value (maker setting value) and the correction value set by the user can be selectively used. Alternatively,
The factory default value (manufacturer's first set value) may be overwritten with a new correction value in the user setting mode.

FIG. 4 is a diagram showing the relationship between the zoom ratio and the focus correction value for explaining the camera of another embodiment of the present invention. This embodiment will also describe the digital camera in FIG.

FIG. 4 shows an example of the focus correction value (the number of steps of the focus lens driving motor 44) with respect to the zoom ratio when the zoom ratio of the zoom lens (for example, 3 × zoom) 11 is changed. .

The present embodiment deals with the case where the focus correction value is not constant with respect to the zoom ratio, and a correction value for correcting the focus lens position is obtained in advance for each digital camera in accordance with the zoom ratio value. This is stored in the storage means 41 as a zoom focus correction value.
Then, as described in steps S1 to S8 in FIG. 2 described above, the focus position shift based on the position shift between the image sensor 32 and the screen mat 21 is corrected, and the focus position for focus is set. When the user instructs the exposure (photographing) operation after setting the zoom ratio with the zoom instruction button, the CPU 34 causes the storage unit 4 to operate.
The focus correction value at the time of zooming is read from 1 according to the set zoom ratio, and the focus position set as the in-focus state is corrected by the focus correction value.

In particular, when the user sets the focus position with the focus instruction button and further sets the zoom ratio with the zoom instruction button during the MF photographing, and then issues the second release operation, the above-mentioned setting is first performed. The focus position is corrected by the first focus correction value (correction value for correcting the focus position shift based on the position shift between the position of the image sensor and the position of the screen mat) stored in the storage unit 41, and then The focus position is corrected with the second focus correction value (correction value for correcting the focus position shift based on the change in zoom) stored in the storage unit 41 according to the set zoom ratio.

As a result, even if the zoom ratio is changed, the focus shift due to the change is corrected, and the M with higher accuracy is obtained.
F operation and AF operation are possible. That is, there is an advantage that it is possible to finely deal with the difference in the shift depending on the zoom ratio.

The example of application to a digital camera has been described above. However, even in a silver salt camera using a silver salt film instead of an image pickup element, the manual displacement is caused by the relative displacement between the film surface and the screen mat which is the focusing screen. Since the same problem as in a digital camera occurs, the present invention can be applied to a silver salt single lens reflex camera.

[0055]

As described above, according to the present invention, it is not necessary to strictly position the film or the image pickup device and the screen mat, and the image at the time of the manual photographing due to the relative displacement between the film or the image pickup device and the screen mat. Can be eliminated, and a camera with higher precision can be realized.

[Brief description of drawings]

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

FIG. 2 is a flowchart illustrating a shooting operation during MF in the camera of FIG.

3 is a flowchart of an operation of calculating and storing a focus correction amount in the camera of FIG.

FIG. 4 is a diagram showing a relationship between a zoom ratio and a focus correction value for explaining a camera of another embodiment of the present invention.

FIG. 5 is a flowchart showing an operation during conventional AF shooting.

FIG. 6 is a flowchart showing an operation during conventional MF imaging.

[Explanation of symbols]

10 ... Shooting lens unit 11 ... Zoom lens 12 ... Aperture 13 ... Focus lens 20 ... Optical finder unit 21 ... Screen mat (focus plate) 22 ... Mirror 23 ... Eyepiece lens 31 ... Prism 32 ... Imaging element 33 ... Imaging circuit 34 ... CPU (including focus correction means and registration means) 41 ... Flash memory (storage means) 42 ... Operation unit (including focus position instruction means) 43 ... Zoom lens drive motor (zoom movement means) 44 ... Focus lens drive motor (Focus moving means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 13/18 G02B 7/11 D 13/36 Z H04N 5/232 G03B 3/00 A F term (reference) 2H011 BA31 EA01 EA10 FA02 2H018 BD09 BE00 2H044 DA01 DA02 DB02 DC00 DC02 2H051 AA01 BA45 CB22 EA10 EB20 5C022 AA13 AB26 AB36 AB44 AB66 AC02 AC51 AC69 CA00

Claims (8)

[Claims] 1. In a single-lens reflex camera, a photographing optical system having a moving means for moving a focus position, an optical finder section capable of confirming a focus by moving the focus position, and a manual focus position adjustment. A camera comprising: an instructing means for instructing, and a focus correction means for correcting the focus position set by the instructing means during manual focus photography. 2. The camera according to claim 1, further comprising a storage unit that stores a focus correction amount by the focus correction unit. 3. The optical finder section includes a focusing screen, and the focus correction amount is a shift amount between a position of a planned focal plane of the photographing optical system and a position of the focusing plate provided at a position equivalent thereto. The camera according to claim 2, which is a value based on the above. 4. The photographing optical system according to claim 1, wherein an image pickup device is provided on a planned focal plane.
Camera described in one. 5. A focusing means (AF) for performing focusing detection based on an image obtained by the image pickup device, and a first focus position obtained by the focusing means and a focusing confirmation of an optical finder section. The camera according to any one of claims 1 to 4, further comprising a registration unit that registers the difference between the second focus positions according to (4) as a correction amount. 6. The camera according to claim 1, wherein the focus correction unit moves the focus position immediately before exposure. 7. The focus correction unit returns the corrected focus position to the focus position set by the instruction unit again after the exposure is completed. Camera. 8. The photographing optical system includes a zoom moving unit, and the storage unit stores a correction amount according to the position of the zoom moving unit. Camera described in one.