JPH07281084A - Photographing image screen size switching possible camera - Google Patents

Abstract

PURPOSE:To provide a photographing image screen size switching possible camera by which a photograph high in focus adjusting performance is obtained even in a panoramic photographing mode and a trimming photographing mode different in enlarging power from ordinary photographing in a normal photographing mode. CONSTITUTION:A photographing image screen size switching possible camera is composed of a photographing mode setting part 1 to set either one of a panoramic photographing mode (trimming) to indicate a wide photographing range by finding a defocus quantity or an object distance by detecting a phase difference quantity of an object image divided into two images and a normal photographing mode to photograph an ordinary photographing range and a selecting part 2 to select either of a first AF operation mode 3 (panorama) in which AF accuracy is high but time-lag is large and a second AF operation mode 4 (normal) in which the AF accuracy is inferior to the first operation mode but the time-lag is small according to output of the photographing mode setting part 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a panoramic camera whose screen size on a film can be switched or an automatic focus detecting device for a camera which can arbitrarily set an enlargement ratio in a laboratory based on information recorded on the film. .

[0002]

2. Description of the Related Art In general, as a camera capable of switching an arbitrary screen size from a standard screen, a panoramic camera is known. When printing from film, this panoramic photography is magnified about 2 times and printed, so that blurring due to automatic focus detection (AF) error, which was not noticeable in normal size printing, becomes noticeable.

Therefore, it is desired to improve the AF accuracy during panoramic photography. In order to solve such a problem, Japanese Unexamined Patent Publication No. 5-333261 discloses a camera equipped with an active autofocus device capable of switching the screen size on a film.
A technique is disclosed in which the number of times of light projection and the integration time are increased relative to the normal mode to improve the distance measurement accuracy.

[0004]

However, the technique disclosed in Japanese Unexamined Patent Publication No. 5-333261 is limited to the active autofocus device, and does not disclose any other AF method.

Generally, there are a passive method and an active method in the AF method, but in the current active method, infrared light is projected toward a subject and the distance is measured by a triangle based on the reflection angle of the reflected light from the subject. Is used. However, since the infrared light active method has a shorter reach of infrared light than the passive method, the detectable distance is limited to a relatively short distance.

Further, there is also a problem that the projected infrared light is deviated from the subject and the distance cannot be correctly measured even if the distance is calculated from the reflected light. Generally, the passive method has a higher focus detection accuracy and the single-lens reflex camera. It is often used in high-end cameras such as flex cameras. Therefore, even in the passive method, it is desired to improve the AF accuracy more than before in panoramic shooting.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a camera capable of switching a photographing screen size to obtain a photograph having a high focusing property even in a panoramic photographing mode and a trimming photographing mode which are different in enlargement magnification from the normal photographing in the normal photographing mode. And

[0008]

In order to achieve the above object, the present invention provides a distance measuring means for detecting a phase difference amount of a subject image, a normal photographing mode for instructing a normal photographing screen size,
Alternatively, when the trimming shooting mode is set by the shooting mode setting means for setting one of the trimming shooting modes for instructing a shooting screen size smaller than the normal shooting screen size and the shooting mode setting means, When the normal AF mode is set after switching to the first AF mode in which the first number of times of distance measurement is designated, the first A mode is set.
From the AF mode switching means for switching to the second AF mode in which the number of distance measurements is smaller than that in the F mode, and the distance measurement output measured by the distance measurement means based on the output of the AF mode switching means, the defocus of the photographing optical system is determined. Provided is a camera capable of switching a photographing screen size, which is configured by a calculation unit that calculates a focus amount or a distance to a subject. .

Further, the distance measuring means for detecting the phase difference amount of the subject image from the light flux passing through the photographing optical system, the normal photographing mode for instructing the normal photographing screen size, or the normal photographing screen size The first shooting mode setting means for setting a small shooting screen size in the trimming shooting mode and the first shooting frequency setting means for setting the first shooting frequency when the trimming shooting mode is set. AF mode switching means for switching to the second AF mode in which the number of times of distance measurement is smaller than the first AF mode when the normal shooting mode is set, and the AF mode switching means. Defocus amount calculation means for calculating the defocus amount of the photographing optical system from the distance measurement output measured by the distance measurement means based on the output; The determination means determines whether the output of the focus amount calculation means is within a predetermined value set in advance, and discards the set number of times of distance measurement when it is determined that the defocus amount is not within the predetermined value. , And a selection means for selecting the first AF mode or the second AF mode based on the output of the defocus amount calculation means and outputting to the AF mode switching means. Provide a camera.

[0010]

With the camera having the above-described configuration and capable of switching the shooting screen size, the normal shooting mode for shooting the normal shooting range or the panorama shooting for instructing a panorama in a wider range than the normal shooting mode is performed by the shooting mode setting means. When any one of the mode and the trimming shooting mode for instructing a narrow range is set and the panoramic shooting mode or the trimming shooting mode is set, the AF accuracy is high based on the set mode by the selecting unit. When the AF operation is performed by selecting the first AF operation mode having a large time lag and the normal photographing mode is set, the selection means causes the AF accuracy to be inferior as compared with the first operation mode, but the time lag is small. The second AF operation mode is selected and the AF operation is performed.

Further, in the camera capable of switching the photographing screen size, the distance measuring means normally detects the phase difference amount of the subject image from the light flux passing through the photographing optical system, and the photographing mode setting means indicates a normal photographing screen size. The shooting mode is set, or the trimming shooting mode instructing a shooting screen size smaller than the normal shooting screen size is set. Then, the AF mode switching means, when the trimming photographing mode is set, the first A
When the mode is switched to the F mode and the normal shooting mode is set, the number of times of distance measurement is smaller than that of the first AF mode in the second A mode.
The defocus amount calculation means calculates the defocus amount of the photographing optical system based on the distance measurement output measured by the distance measurement means based on the switching to the F mode. The determination means determines whether the defocus amount calculation output is within a predetermined value set in advance, and when it is determined that the defocus amount is not within the predetermined value, the set number of times of distance measurement is discarded. Then, based on the output of the defocus amount calculation means,
The selection means selects the first AF mode or the second AF mode.

Further, the camera capable of switching the photographing screen size is constructed in the same manner as the above-mentioned constitution, and further, a focusing threshold variable means for generating a predetermined focusing threshold based on the selected photographing mode, and a defocus amount generating means. A focus determination means for determining whether the focus is within the focus threshold, and when the shooting mode setting means sets either the panoramic shooting mode or the trimming shooting mode, the focus threshold varying means normally shoots. A focusing threshold smaller than the focusing threshold of the second AF operation mode set in advance as a mode is generated, and the small focusing threshold is set as the first AF operation mode, and the defocus amount and the small defocus amount are determined by the focusing determination means. The focus thresholds are compared to determine if they are within the predetermined range, and if they are within the predetermined range, focus If outside the range, to the lens drive by correcting a defocus amount.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a schematic structure of a camera capable of switching a shooting screen size as a first embodiment according to the present invention. This camera can obtain the defocus amount or the subject distance by detecting the phase difference amount of the subject image divided into two images.

The camera capable of switching the photographing screen size has a normal photographing mode for photographing a normal photographing range,
The panorama shooting mode for instructing a panorama over a wider range than the normal shooting mode and the shooting mode setting unit 1 for setting one of a trimming shooting mode for instructing a narrow range, and the shooting mode setting unit 1 described above. Based on the output, one of the first AF operation mode 3 with high AF accuracy but a large time lag and the second AF operation mode 4 with inferior AF accuracy but a small time lag compared to the first operation mode is selected. And the selection unit 2.

When the panoramic shooting mode or the trimming shooting mode is selected and set by the shooting mode setting unit 1, the selecting unit 2 selects the first AF operation mode 3 to perform the AF operation. When the normal shooting mode is set by the shooting mode setting unit 1, the selection unit 2 sets the second AF
The operation mode 4 is selected to perform the AF operation.

The first AF operation mode 3 is the second A mode.
Since it is possible to perform AF with higher accuracy than in the F operation mode 4, it is possible to improve the AF accuracy in shooting in the panoramic shooting mode or the trimming shooting mode as compared with the normal shooting mode.

Next, FIG. 2 shows a schematic structure of a camera capable of switching a photographing screen size as a second embodiment according to the present invention. This camera is a camera capable of obtaining the defocus amount or the subject distance by detecting the phase difference amount of the subject image divided into two images.

This camera capable of switching the photographing screen size includes a photoelectric conversion unit 7 for photoelectrically converting a subject image divided into two images by an optical system (not shown), a normal photographing mode for instructing a normal photographing range, and a normal photographing. A panoramic shooting mode that indicates a wider panorama range than the mode,
A shooting mode setting unit 1 for setting any one of a trimming shooting mode for instructing a narrow range, and a measurement number switching unit 5 for switching the measurement number of the photoelectric conversion unit 7 based on the output of the shooting mode setting unit 1. A measuring unit 6 that causes the photoelectric conversion unit 7 to repeatedly perform measurement based on the output of the measurement number switching unit 5; and a calculation unit 8 that calculates the defocus amount or the subject distance based on the output of the photoelectric conversion unit 7.
Composed of and.

In this camera, when either the panoramic shooting mode or the trimming shooting mode is set by the shooting mode setting unit 1, the measurement number switching unit 5 selects the first AF operation mode to perform the normal shooting. The number of times of measurement larger than that in the mode (second AF operation mode) is instructed. Then, the measurement unit 6 causes the photoelectric conversion unit 7 to repeatedly perform measurement based on the instructed number of times of measurement.

The calculation unit 8 calculates the defocus amount or the subject distance based on the measurement result of the photoelectric conversion unit 7. However, since the number of times of measurement is large compared to the second AF operation mode, it is repeated by statistical processing. It is possible to reduce variations in turning back. As a result, in the panoramic shooting mode or the trimming shooting mode, more accurate automatic focus detection can be performed as compared with the normal shooting mode.

FIG. 3 shows a schematic structure of a camera capable of switching a photographing screen size as a third embodiment according to the present invention. This camera is a camera that obtains the defocus amount of the photographing optical system by dividing a subject image that has passed through the photographing optical system into two images and measuring the light intensity distribution of each image. Here, in the constituent members of the third embodiment, the same members as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

This camera capable of switching the image capturing screen size includes a photoelectric conversion section 7 for photoelectrically converting an object image divided into two images, an image capturing mode setting section 1, and a measurement number switching section 5.
The measuring unit 6, the photoelectric conversion unit 7, the calculation unit 8, and the defocus amount determination unit 9 that compares the detected defocus amount output from the calculation unit 8 with a predetermined defocus amount. It

In this third embodiment, the measuring section 6
Is based on the output of the defocus amount determination unit 9 and the output of the measurement number switching unit 5, the first AF having a larger number of measurement times.
The photoelectric conversion unit 7 is caused to perform measurement by selecting either the operation mode or the normal second AF operation mode.

FIG. 4 shows a schematic structure of a camera capable of switching a photographing screen size according to a fourth embodiment of the present invention. This camera divides the subject image that has passed through the photographic optical system into two images, and measures the light intensity distribution of each image to obtain 2
It is a camera that obtains the defocus amount of the photographing optical system from the image interval.

This camera capable of switching the photographing screen size has a normal photographing mode for instructing a normal photographing range,
A shooting mode setting unit 1 for setting at least one of a panoramic shooting mode for designating a wider panorama range and a trimming shooting mode for designating a narrower range than the normal shooting mode, and photoelectric conversion of a subject image divided into two images. Photoelectric conversion unit 7, a calculation unit 8 that calculates the defocus amount based on the output of the photoelectric conversion unit 7, a focus threshold variable unit 10 that generates a predetermined focus threshold based on the shooting mode, and the defocus amount. The focus determination unit 11 determines whether or not the focus threshold is within the range.

In this camera, the photographing mode setting unit 1
As a result, when either the panoramic shooting mode or the trimming shooting mode is set, the focus threshold variable unit 10 generates a focus threshold smaller than that in the second AF operation mode as the first AF operation mode. Based on the generated focus threshold, the focus determination unit 11
It is determined whether the defocus amount is within the focusing threshold. Here, the first AF operation mode is the second AF
Since the focus threshold is smaller than that in the operation mode, more accurate automatic focus detection can be performed.

FIG. 5 shows a schematic structure of a camera capable of switching a photographing screen size as a fifth embodiment according to the present invention. This camera is a camera that obtains the defocus amount of the photographing optical system by dividing a subject image that has passed through the photographing optical system into two images and measuring the light intensity distribution of each image.

This camera capable of switching the photographing screen size indicates a normal photographing mode indicating a normal photographing range, a panoramic photographing mode indicating a panoramic range wider than the normal photographing mode, and a trimming range narrower than the normal photographing mode. Shooting mode setting unit 1 for setting at least one of trimming shooting modes
And an AF operation mode setting unit 12 that selects an AF operation mode based on the output of the shooting mode setting unit 1, and as a final operation of the AF operation, it is detected that the defocus amount is within a predetermined focusing threshold, and the result is detected. As the closed loop AF control mode 13 for focusing, and as the final operation of the AF operation, the defocus amount is within a predetermined determination defocus amount larger than the focusing threshold, and the previous lens driving direction and the current lens driving should be performed. When the directions match, the open-loop AF control mode 14 in which focusing is performed without performing the focusing determination after driving the lens
Composed of and. The closed loop AF control mode 13 and the open loop AF control mode 14 are disclosed in detail in Japanese Patent Application Laid-Open No. 63-115119 proposed by the present applicant, and a description thereof will be omitted here.

In the closed loop control mode 13, the focusing threshold can be set to a small value, so that automatic focus detection can be performed with higher accuracy than in the open loop AF control mode 14. If the shooting mode setting unit 1 sets the panoramic shooting mode or the trimming shooting mode, A
The F operation mode selection unit 12 selects the closed loop AF mode 13, and also selects the open loop AF mode 14 when the normal photographing mode is selected.

Therefore, in the present embodiment, when the panoramic shooting mode or the trimming shooting mode is selected, it is possible to perform more accurate automatic focus detection than in the normal shooting mode.

Next, FIG. 6 is a diagram showing the configuration of a control system of an automatic focus detection device in a camera capable of switching a photographing screen size as a sixth embodiment according to the present invention. In this automatic focus detection device, the subject light passes through the taking lens 38, and the condenser lens 36 and the separators 35L and 35L.
When it reaches the photosensor arrays 34L and 34R arranged on the upper surface of the AFIC 112 through the AF optical system composed of R and R, the AFIC 112 performs processing such as light amount integration and quantization described later, and the distance measurement information is obtained from the AFIC 112.
Is transferred to the CPU 111. The CPU 111
Sequentially executes programs previously stored in an internal ROM (not shown) to control peripheral integrated circuits (ICs) and the like. Further, in this embodiment, an auto focus (AF) IC
A TTL phase difference detection method is used for the automatic focus adjustment by 112.

If there is a variation in the characteristics that occurs when the elements of the photosensor arrays 34L and 34R are manufactured, accurate distance measurement information cannot be obtained. Therefore, in this embodiment, the EEPROM 1 which is a nonvolatile recording element is used.
Information regarding the variations of the photosensor arrays 34L and 34R is stored in advance in the CPU 13, and the distance measurement information obtained from the AFIC 112 is stored in the CPU 11 based on this information.
Corrected by 1.

The information on the above-mentioned variation is, for example, mechanical variation or variation in electrical characteristics of various elements,
The various adjustment values required are set in advance and the EEPROM
The adjustment value is stored in the memory 113, these adjustment values are read out as necessary, and various calculations are performed in the CPU 111 to correct the distance measurement information. The CPU 111 and AFIC
Data is exchanged between the 112 and the EEPROM 113 by serial communication.

The data bag 15 connected to the CPU 111 imprints the date on the film based on the control signal output from the CPU 111. The light quantity of the imprinting lamp of the data bag 15 changes stepwise depending on the film ISO sensitivity. The interface IC (IFIC) 17 is a C
Performs 4-bit parallel communication with the PU111 to measure the subject brightness, measure the camera temperature, shape the output signal waveform of the photo interrupter, etc., control the constant voltage drive of the motor, stabilize the temperature, and adjust the constant voltage such as temperature proportional voltage. It performs generation, battery remaining amount check, reception of infrared remote controller, control of motor driver ICs 18 and 19, control of various LEDs, check of power supply voltage, control of booster circuit, and the like.

Then, the silicon photodiode (SP
D) 33 measures the subject brightness. This SPD3
The light receiving surface of 3 is divided into a central portion of the screen and a peripheral portion thereof, and two types of photometry are performed, that is, spot photometry in which only a part of the center of the screen is measured and average photometry in which the entire screen is used for photometry. . The SPD 33 outputs a current according to the subject brightness to the IFIC 17,
17 converts this output into a voltage and transfers it to the CPU 111. In the CPU 111, the exposure calculation, the judgment of backlight, and the like are performed based on the information including the voltage.

Further, when the circuit built in the FIC 17 outputs a signal composed of a voltage corresponding to the absolute temperature, the signal is A / D converted by the CPU 111 to obtain a temperature measurement value of the temperature inside the camera. Is output. This temperature measurement value is used as a reference for correction of mechanical members whose electrical state changes depending on temperature, electrical signals, and the like.

Further, in the waveform shaping of the photo interrupter or the like, the photocurrent of the output of the photo interrupter or the photo reflector is compared with the reference current, and IFIC is formed as a rectangular wave.
Output from 17. At this time, noise is removed by giving a hysteresis characteristic to the reference current. Further, the reference current and the hysteresis characteristic can be changed by the communication with the CPU 111.

Further, in checking the remaining capacity of the battery, the voltage across the battery when a low resistance is connected to both ends of the battery (not shown) and a current is applied is divided inside the IFIC 17 and output to the CPU 111. A /
D conversion is performed and the obtained A / D value is used.

In the reception of the infrared light remote controller, the modulated infrared light is emitted from the light emitting LED 31 of the remote controller transmitting unit 30, and the infrared light is received by the light receiving silicon photodiode 32. To do. And
The output signal of the silicon photodiode 32 is IF
After the processing such as waveform shaping is performed inside the IC17, the CPU
It is transferred to 111.

The IFIC1 is used to monitor the power supply voltage for low voltage.
7 is provided with a dedicated terminal for that purpose, and if the power supply voltage input to the dedicated terminal falls below a specified value, the IF
A reset signal is output from the IC 17 to the CPU 111, and errors or the like of the CPU 111 are prevented in advance. Then, when the power supply voltage drops below a predetermined value, the booster circuit is controlled to boost the voltage.

Then, the IFIC 17 has an LED 2 for display in the finder for AF distance measurement completion, strobe emission warning, etc.
9 or LE used for photo interrupter etc.
D is connected, and on / off of these LEDs and control of the amount of emitted light are controlled by the CPU 111 and the EEPROM 1.
3. The communication between the IFICs 17 is performed directly by the IFICs 17. The IFIC 17 also controls the constant voltage of the motor.

Further, the motor driver IC 18 has a shutter charge (SC) motor 22 for film feeding and shutter charging, a lens driving (LD) motor 23 for focus adjustment, and a lens frame zooming (ZM). The three motors of the motor 24 are driven, the booster circuit is driven, the self-timer operation display LED is driven, and the like. The control of these operations, for example, "which device is driven", "whether the motor is normally or reversely rotated", "whether the braking is applied", and the like are performed by the CPU 11
IFIC17 receives the signal from the IFIC1
7 controls the motor driver IC 18.

Whether the SC motor 22 is in the shutter charge, film winding, or rewinding state is determined by using the photo interrupter and the clutch lever.
Detected by I25, the information is transferred to the CPU 111. The amount of lens extension is detected by the LDPI 26 attached to the LD motor 23, and the output is IFIC.
The waveform is shaped in 17 and then transferred to the CPU 111.

Further, the amount of lens frame zooming out is detected by ZMPI 28 and ZMPR 27. Then, when the mirror frame is between the TELE end and the WIDE end, the ZMPR 27 is configured to pick up the reflection of the silver sticker attached to the mirror frame. The output of the ZMPR 27 is input to the CPU 111 and the TELE end and the WIDE end are detected.

Then, the ZMPI 28 is attached to the ZM motor 24, the output of which is waveform-shaped by the IFIC 17 and then input to the CPU 111, and the TELE end or the WID.
The amount of zooming from the E end is detected. Then, the motor driver IC 19 drives the AV motor 20, which is a stepping motor for driving the aperture adjustment unit, by the control signal from the CPU 111, and the AVPI 21 outputs its output to I
The FIC 17 shapes the waveform and outputs it to the CPU 111 to detect the aperture open position.

The liquid crystal display panel 114 is the CPU 11
The number of film frames, the shooting mode, the flash mode, the aperture value, the battery level, etc. are displayed by the signal sent from 1. Then, the strobe circuit 16 gives a necessary brightness to the subject by causing the arc tube to emit light when the brightness of the subject is insufficient at the time of photographing or AF distance measurement.
The IFIC 17 controls based on the signal from the.

Further, the first release switch R1
The SW is turned on when the release button is half pressed, and the distance measuring operation is performed. Then, the second release switch R2SW is turned on when the release button is fully pressed, and the photographing operation is performed based on various measured values. Further, the zoom-up switch ZUSW and the zoom-down switch ZDSW are switches for zooming the lens frame, and when ZUSW is turned on, Z is moved in the long focus direction.
When the DSW is turned on, zooming is performed in the short focus direction. When the self-switch SELFSW is turned on, the self-timer shooting mode or the remote control standby state is set. In this state, if the R2SW is turned on, self-timer shooting is performed, and if a shooting operation is performed by the remote control transmitter 30, shooting is performed by the remote control.

When the spot switch SPOTSW is turned on, the "spot metering mode" is set in which metering is performed only in a part of the center of the photographing screen. This is photometry by the AF sensor described later. In the normal photometry with the SPOTSW off, evaluation photometry is performed by the photometric SPD 33. Further, the PCT1SW to PCT4SW and the program switch PSW are "program photographing mode" changeover switches, and the photographer selects a mode according to photographing conditions.
When the PCT1SW is turned on, the "portrait mode" is set, and the aperture and shutter speed are determined so that the depth of field becomes shallow within the proper exposure range.

When the PCT2SW is turned on, the "night view mode" is set, and the value is set to be one step lower than the value of the proper exposure at the time of normal photographing. When the PCT3SW is turned on, the "landscape mode" is set, and the aperture and shutter speed values are determined so that the depth of field is as deep as possible within the proper exposure range. Further, when the PCT4SW is turned on, the "macro mode" is set, which is used during close-up photography. Two or more of these PCT1SW to PCT4SW can be selected at the same time.

The PSW is a normal "program shooting mode" changeover switch. By pressing this PSW, the PCT1SW to PCT4SW are reset and the AV priority program mode described later is reset.
Further, when the AV priority switch AVSW is turned on, the shooting mode becomes the "AV priority program mode". In this mode, the photographer determines the AV value, and the shutter speed is determined by a program according to the AV value. In this mode, the PCT2SW and PCT4SW have no function as described above and serve as AV value setting switches. Furthermore, PCT2
SW is a switch for increasing the AV value, and PCT4SW is A
It is a switch that reduces the V value.

Further, the strobe switch STSW is a strobe light emission mode changeover switch, which is usually "automatic light emission mode (AUTO)" or "red-eye reduction automatic light emission mode (AUTO).
-S) "," Forced flash mode (FILL-IN) ",
Switch "Strobe off mode (OFF)". Also,
The panorama switch (PANSW) is a switch for detecting whether the shooting state is panoramic shooting or normal shooting, and is turned on during panoramic shooting. When the shooting mode is panorama, photometry correction calculation and the like are performed. This is because the upper and lower parts of the shooting screen are masked during panorama shooting.
This is because a part of the photometric sensor is also masked, and accurate photometry cannot be performed.

Further, when the photographing mode is panorama, higher precision AF is required, so higher precision AF is required.
This is for selecting the operation mode. Further, the back cover switch BKSW is a switch for detecting the state of the back cover, and when the back cover is closed, it is turned off. When the state of the BKSW changes from on to off, loading of the film is started. Also, the shutter charge switch SCS
W is a switch for detecting shutter charge.

Further, the mirror-up switch MUSW is a switch for detecting the mirror-up and is turned on by the mirror-up. Then, the DX switch DXSW is a D indicating the film sensitivity printed on the film cartridge.
It consists of five switch groups (not shown) for reading the X code and for detecting the presence / absence of film loading.

The strobe unit 16 includes the CPU 1
The main capacitor is charged by the signal from 11, and the CPU 111 detects the output obtained by dividing the voltage of the main capacitor and stops the charging. CP for strobe emission control
A light emission signal is output from U111 via the IFIC 17 and input to the strobe unit 16. Further, in this embodiment, the strobe unit 16 is used as AF auxiliary light.

Next, with reference to the flow chart shown in FIG. 7, the sequence of the subroutine "first release" executed by the camera of the present invention capable of switching the photographing screen size will be described in detail.

First, a subroutine "AF distance measurement" described later
Is executed (step S1), and it is determined whether or not the AF distance measurement result is undetectable by referring to the undetectable flag (step S2). If the result of the AF distance measurement is detected in this determination (NO), it is determined whether or not the focus is achieved by referring to the focus flag (step S4). In the case of focusing here (YE
S), focus display is performed by the LED display in the finder and the sound of the buzzer (step S5), and the process returns.

On the other hand, if it is determined in step S4 that the object is out of focus (NO), a subroutine "lens drive", which will be described later, is executed and lens drive is performed based on the result of the AF distance measurement (step S6). . Further, after the lens is driven, it is determined whether or not the focus is achieved by referring to the focus flag (step S7). If the focus is achieved (YES), the focus display is performed (step S5). (NO) returns to step S1 and executes the subroutine "AF distance measurement" again.

If the result of the determination in step S2 is that detection is not possible (YES), then out-of-focus display is performed by means of the LED in the finder (step S3), and then the process returns.

Next, referring to the flowchart shown in FIG. 8, the subroutine "A" executed in step S1 in FIG.
The sequence of "F distance measurement" will be described. First, the subroutine "AF sensor integration" is executed, and the AFIC 112 is executed.
AF sensor integration is performed by the photoelectric conversion element arrays 34R and 34L. AFIC when AF sensor integration is completed
An integration end signal is output from the CPU 112 to the CPU 111, whereby the CPU 111 stops the internal timer, measures the integration time, and stores it in the RAM (step S1).
1).

Here, this photoelectric conversion element array 34R, 34
Regarding the AF optical system 37 for forming a subject image on L, the subject image formed by the taking lens 38 is divided into two subject images by the re-imaging optical system, and re-combined on the photoelectric conversion element array. A focus detection optical system for performing focus detection by detecting the positional shift between the image and the two subject images is already known, and therefore a detailed description thereof will be omitted.

Next, the sensor reading operation is performed (step S12). That is, when a clock is input from the CPU 111 to the AFIC 112, sensor data is sequentially output in synchronization with this, and the CPU 111 sequentially stores the sensor data in a predetermined RAM (not shown).

Then, it is determined whether or not the panorama mode is set (step S13), and when the panorama mode is not set (NO), the process shifts to a photometric value calculation in step S17 described later. However, when in panorama mode (YE
S), it is determined whether the current defocus amount stored in the RAM is within a predetermined defocus amount (step S
14) If it is larger than the predetermined defocus amount (N
O), and shifts to the photometric value calculation in step S17. When the defocus amount is larger than the predetermined defocus amount, other error factors such as a lens driving error are large, so that the effect of the averaging process is low, and an extra time lag occurs, so that the averaging process is not performed. In addition, AF measurement data is not averaged but distance measurement data after calculation (image shift amount, defocus amount)
May be averaged, but this is not preferable because the time lag increases for the calculation time.

When the subject has low brightness and the integration time of the AF sensor is long, the time lag increases when repeated measurement is performed. Therefore, the number of measurements may be reduced according to the integration time. Alternatively, when the auxiliary light is emitted and integration is performed, the time lag similarly increases due to the charging time for charging the main capacitor in the strobe circuit 16. Therefore, it is also effective to prohibit the increase in the number of measurements at this time. Is.

On the other hand, if it is determined in step S14 that the defocus amount is within the predetermined amount (YES), the measurement in steps S11 to S14 is repeated up to the predetermined number n to improve the AF accuracy (step S14). S1
5) The AF sensor data of the predetermined number n is averaged to reduce repetitive variations such as power source noise and random noise of the AF sensor itself (step S16).

Then, the photometric value of the subject is calculated using the read sensor data (step S17). This photometric value is used to calculate exposure data and determine the need for auxiliary light,
It is also used to judge the reliability of the obtained sensor data.

Next, a subroutine "determination of auxiliary light" is executed (step S18), and when the AFIC 112 is integrated and the brightness is low and the light amount is insufficient, the auxiliary light for illuminating the subject with auxiliary illumination light is turned on. A process of determining whether or not it is necessary and setting the light amount of the auxiliary light is performed. It is determined whether or not the auxiliary light is emitted during this integration, and if the auxiliary light is not emitted, it is determined whether or not the auxiliary light is required during the next integration. Here, the integration time of the AFIC 112 is compared with a predetermined determination time, and when the integration time is longer, that is, when the subject has low brightness, it is determined that auxiliary light is necessary. Then, the auxiliary light request flag is set.

Next, the illuminance distribution is corrected (step S
19). In this illuminance distribution correction, non-uniformity correction of the obtained subject image signal is performed. This is to correct the sensitivity variation caused by the non-uniform illuminance on the AF sensor surface due to the re-imaging optical system and the variation of the photodiode of the photoelectric conversion element array, the storage capacitor and the like. The correction coefficient calculated from the sensor data of each element with respect to the uniform light source is stored in the EEPROM 13 for each element in advance, and the correction coefficient is read every time the subject image signal is detected,
Correction calculation is performed for each element.

Then, the subroutine "correlation calculation" is performed (step S20), and the correlation calculation is performed on the two object images to detect the interval between the two images. Here, the first subject image is the L image, and the first subject image signal is L (I). Also,
The second subject image is the R image, and the second subject image signal is the R image.
(I). I is an element number, which is 1, 2, 3, ..., 64 in the order of arrangement in this embodiment. That is, each element row 34
It is assumed that each of L and 34R has 64 elements.

Here, the sequence of the subroutine "correlation operation" executed in step S20 of FIG. 8 will be described with reference to the flowchart of FIG. First, variables SL, SR, and J have initial values of “5”,
Set "37" and "8" (steps S41 and S42)
To do. This SL is a variable for storing the leading number of the small block element array for correlation detection from the subject image signal L (I), and SR is for the small block element row for correlation detection from the subject image signal R (I). A variable that stores the leading number
Is a variable that counts the number of times the small block moves in the subject image signal L (I). Then, the correlation output F (S) is calculated by the following formula (step S443).

[0070]

[Equation 1] In this case, the number of elements in the small block is 27. The number of elements of the small block is determined by the size of the distance measuring frame displayed on the finder and the magnification of the detection optical system.

Then, the minimum value of the correlation output F (S) is detected. That is, if F (S) is compared with Fmin, if F (S) or Fmin
If smaller, substitute F (S) for Fmin and then S
L and SR are stored as SLM and SRM (step S
44, S45).

Further, SR is decremented and J is decremented (step S46). If J is not "0", the correlation calculation is repeated (step S47). That is, the image L
The position of the small block in is fixed, and the position of the small block in the image R is shifted by one element to obtain the correlation.

When J becomes "0", 4 is added to SL, 3 is added to SR, and the correlation calculation is continued (step S48). That is, the correlation calculation is repeated while shifting the small block position in the image L by four elements. The value of SL is 2
When it becomes 9, the correlation calculation is ended (step S49). As described above, the correlation calculation can be performed efficiently and the minimum value of the correlation output can be detected. The position of the small block showing the minimum value of the correlation output indicates the positional relationship of the image signals having the highest correlation. Then, in order to determine the correlation of the detected block image signal having the highest correlation, the correlation outputs FM and FP shown by the following equations are calculated (step S5).
0).

[0074]

[Equation 2] That is, the correlation output when the object image R is shifted by ± 1 element with respect to the small block position showing the minimum correlation output is calculated. At this time, FM, Fmin, and FP are shown in FIG.
The relationships are as shown in (a) and (b). Incidentally, FIG.
The horizontal axes of (a) and (b) represent the position of the photoelectric conversion element, and the vertical axis represents the correlation output. The correlation output F (S) becomes “0” at the point S ₀ . On the other hand, when the correlation is low, it does not become "0".

Then, in order to determine the correlation, the correlation indices SK and FS shown in the following equations are obtained (step S5).
1). When FM ≧ FP SK = (FP + Fmin) / (FM-Fmin) (4) FS = FM-Fmin (5) When FM <FP SK = (FM + Fmin) / (FP-Fmin) (6) FS = FP-Fmin (7) The correlation index SK is SK = 1 when the correlation is high and SK> 1 when the correlation is low. Therefore, it is possible to determine whether or not the detected image shift amount is reliable based on the value of the correlation index SK. Further, since the correlation index FS corresponds to the contrast of the small block image signal having the highest correlation, the larger the value, the higher the contrast.

Next, returning to the flowchart of FIG. First, the correlation is determined (step S21). The correlation indices SK and FS are used for this correlation determination. However,
The correlation index SK is actually "1" because the first and second subject images do not completely match due to variations in the optical system, noise of the photoelectric conversion element, conversion error, and the like.
It doesn't.

Therefore, the determination is made using the predetermined determination value α. A predetermined judgment value β is used for the correlation index FS. That is, if SK ≦ α and FS ≧ β, it is determined that there is a correlation, and if SK> α or FS <β, it is determined that there is no correlation, it is determined that AF detection is not possible, and the detection impossible flag is set. These judgment values α and β are stored in the EEPROM 113 because they vary depending on the product and different judgment values are used depending on the photographing mode and the AF operation mode.

If it is determined in step S21 that there is a correlation (YES), the image shift amount is calculated (step S22). Here, since the interval ZR between the first and second subject images is S ₀ shown in FIG. 10A, FM ≧
When FP ZR = SRM-SLM + (FM-FP) / {(FM-Fmin) · 2} (8) When FM <FP ZR = SRM-SLM + (FP-FM) / {(FP-Fmin) · 2} (9)

Next, the image shift amount ΔZR from the focus is expressed by the following equation. ΔZR = ZR−ZR0 (10) However, ZR0 is the subject image interval at the time of focusing and is stored in the EEPROM 113 for each camera.

Next, the image shift amount ΔZR is converted into the defocus amount ΔDF (step S23). The shift amount of the image formation position with respect to the film surface on the optical axis, that is, the defocus amount ΔDF can be obtained by the following equation.

ΔDF = BD / (AD−ΔZR) −CD (11) Here, AD, BD, and CD are constants determined by the AF optical system. This is disclosed in Japanese Patent Laid-Open No. 62-100718, and a detailed description thereof will be omitted here.

Next, aberration correction is performed (step S2).
4). That is, the focus position of the AF optical system shifts depending on the focal length and the focusing extension position due to the influence of the spherical aberration of the taking lens 38, which is corrected. This correction value is E depending on the focal length of the taking lens 38 and the subject distance.
The correction is performed using the correction value stored in the EPROM 13.

Then, a release focus shift correction process for correcting the focus shift at the time of exposure is performed (step S2).
5). This is for predicting and correcting the shift of the image forming position during the shooting stop operation, and since this correction is disclosed in Japanese Patent Laid-Open No. 4-30669, detailed description thereof will be omitted here.

Further, it is determined whether the detected defocus amount ΔDF is within the focusing allowable range. First, it is determined whether or not the panorama mode is set (step S26). When the panorama mode is not set (NO), the process proceeds to step S329, and a predetermined focusing threshold is compared with the corrected defocus amount (step S29). If it is within the focus threshold (YES), the focus flag is set (step S3).
0), return.

On the other hand, when the focus threshold is exceeded in step S29 (NO), the lens drive pulse amount is calculated from the corrected defocus amount (step S31), and the process returns.

In step S26, in the panorama mode (YES), a panoramic focusing threshold having a narrower range than the normal focusing threshold is set in order to perform more accurate AF (step S28). In step S29, the focus determination is performed using the focus threshold for panorama.

Various proposals have been made for the method of converting the detected defocus amount ΔDF into the lens extension amount ΔLK in the optical axis direction. For example, JP-A-64-5
In the one disclosed in Japanese Patent No. 4409, it is calculated by the following equation.

ΔLK = Aa− (Aa × Ba) / (Aa + ΔDF) + Ca × ΔDF (12) where Aa, Ba, and Ca are constants stored for each focal length.

The focusing lens of the taking lens 38 is driven by the LDM 23 via a gear train, and the movement amount of the focusing lens is input to the IFIC 17 as an AFPI pulse by the LDPI 26. Therefore, the amount of lens extension ΔLK in the optical axis direction is equal to the AFP per unit amount of extension.
When the lens driving pulse amount DP is obtained by multiplying the I pulse number K, it is shown by the following equation.

DP = K × ΔLK (13) Note that the image shift amount ΔZR in the expression (10) and the defocus amount ΔDF in the expression (11) are both signed values. When the value is positive, the direction in which the lens is extended by the rear pin (imaging on the rear side of the film surface) is shown, and when the value is negative, the direction in which the lens is extended by the front pin (imaging on the front side of the film surface) is indicated.

Step S2 of the flowchart of FIG.
If there is no correlation in the determination of 1 (NO), the out-of-focus flag is set (step S27), the process returns and the sequence of this subroutine "AF distance measurement" is ended.

Next, the sequence of the subroutine "lens drive" executed in step S6 of FIG. 7 will be described with reference to the flowchart shown in FIG. First, A
It is determined whether the number of lens driving pulses calculated in the F distance measuring process is larger than a predetermined value (step S61). As the predetermined determination value, in the normal photographing mode, the number of lens drive pulses that can always drive the lens within the in-focus range with one lens drive is used. Here, it is set to 400 pulses, for example.

If the number of lens driving pulses is less than 400 (YES), it is determined by the flag whether the backlash driving has already been completed (step S6).
2) If the backlash drive is not completed yet (NO), it is determined whether or not the lens drive direction is reversed from the last time (step S63). If it is the same as the previous lens drive direction (NO), the lens drive is executed based on the lens drive pulse number of the AF distance measurement result (step S67).

Then, it is determined whether or not the panorama mode is set (step S68). If the panorama mode is not set (NO), the focus flag is set (step S69) and the process returns.
As described above, in the normal shooting mode, the number of remaining drive pulses that can always be regarded as in-focus with one lens drive, and since the lens drive direction is the same direction as the previous time, there is no backlash and AF range measurement is not performed again. Performs open-loop control to achieve focus. On the other hand, in step S68, if the panoma mode is set (YES), the lens is driven and the process returns.

Then, in FIG. 7, AF in step S1
The ranging routine is executed again, and the A
F-sensor data measurement (loop of steps S11 to S15 shown in FIG. 8) and focus determination based on the reduced focus threshold (steps S26, S28 shown in FIG. 8).
S29) is performed to perform more accurate AF.

Then, returning to step S62, it is determined whether the backlash drive has been completed by referring to the backlash drive completed flag. If the backlash has been completed (YES), the lens drive (step S67) and the panorama mode are determined. (Step S68), the focus flag is set (step S69), and the process returns.

Returning to the determination in step S63, if the lens driving direction is the reverse direction with respect to the previous time, (Y
ES) and backlash amount calculation (step S
64). The amount of backlash changes depending on the focal length of the taking lens and the driving direction, so calculations are made accordingly.

Then, based on the calculated backlash amount, the lens is driven by the number of lens driving pulses corresponding to the backlash amount (step S65). And
The backlash driven flag is set (step S66) and the process returns. In this case, AF distance measurement processing and lens drive processing are performed again on the main flow.

Next, returning to the determination in step S61, the AF
When the number of lens drive pulses calculated by distance measurement is 400 or more (NO), a predetermined value is subtracted from the lens drive pulse to obtain a new lens drive pulse (step S).
70). This predetermined value is a correction value indicating a position before the focal point in the lens drive pulse, and is 200 pulses in this example, for example.

Then, the lens is driven based on the corrected lens driving pulse (step S71). With this lens drive, even if there is backlash, it will be removed. Further, the backlash driven flag is set (step S72) and the process returns. As a result, the lens is in the position of 200 pulses as the driving pulse number before the focusing point, so that AF distance measurement and lens driving processing are called again in the main flow to bring the lens into focus.

The sequence of the subroutine "first release" executed in the camera capable of changing the image-capturing screen size of the camera of the present embodiment has been described above. Next, referring to the flowchart of FIG. 12, it is executed in the camera of the present embodiment. The sequence of the subroutine "second release" performed will be described.

First, when the second release R2SW is pressed to enter this subroutine, the mirror is raised (step S81), and then the front curtain is started (step S82). Next, it is checked whether strobe light emission is necessary (step S83), and if yes (YES), the strobe light is emitted (step S84).

On the other hand, if it is determined in step S83 that strobe light emission is unnecessary (NO), the process moves to the next step, the trailing curtain is started to end exposure (step S85), and the mirror is lowered (step S86). The shutter is charged to the initial state (step S87), the film is wound up (step S88), and the photographing is finished.

As described in detail above, when the panorama mode is set, the first AF operation mode with higher accuracy is executed as compared with the second AF operation mode in the normal mode. This enables highly accurate automatic focus detection. The first AF operation mode is to average the sensor data a plurality of times in steps S15 and S16 in FIG. 8 described above, reduce the focusing threshold in step S28 in FIG. 8, and step S68 in FIG. There is an AF operation mode in which the open-loop control is changed to the closed-loop control in (1), and the automatic focus detection accuracy can be improved.

The camera of the present embodiment, which is capable of switching the shooting screen size, has a higher AF accuracy than the second AF operation mode when the panoramic shooting mode or the trimming shooting mode is set. Since the operation mode is selected, it is possible to obtain a highly focused photograph in panoramic photography or trimming photography.

[0106]

As described in detail above, according to the present invention, 2
In a camera that can perform auto focus detection by detecting the amount of focus shift and subject distance by detecting the phase difference amount of the subject image divided into images, the enlargement magnification is different from normal shooting in normal shooting mode It is possible to provide a camera whose shooting screen size can be switched to obtain a photograph with high focus even in the panoramic shooting mode and the trimming shooting mode.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a camera capable of switching a shooting screen size as a first embodiment according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of a camera capable of switching a shooting screen size as a second embodiment according to the present invention.

FIG. 3 is a diagram showing a schematic configuration of a camera capable of switching a shooting screen size as a third embodiment according to the present invention.

FIG. 4 is a diagram showing a schematic configuration of a camera capable of switching a shooting screen size as a fourth embodiment according to the present invention.

FIG. 5 is a diagram showing a schematic configuration of a camera capable of switching a shooting screen size as a fifth embodiment according to the present invention.

FIG. 6 is a diagram showing a configuration of a control system of an automatic focus detection device in a camera capable of switching a shooting screen size according to a sixth embodiment of the present invention.

FIG. 7 is a flow chart for explaining in detail a sequence of a subroutine “fast release” executed by a camera capable of switching a shooting screen size according to the present invention.

8 is a flowchart for explaining a sequence of a subroutine "AF distance measurement" executed in step S1 of the flowchart shown in FIG.

9 is a flowchart for explaining a sequence of a subroutine "correlation calculation" executed in step S20 of the flowchart shown in FIG.

FIG. 10 is a diagram showing output characteristics of a position of a photoelectric conversion element and a correlation output value.

FIG. 11 is a flowchart for explaining a sequence of a subroutine “lens driving” executed in step S6 of the flowchart shown in FIG. 7.

FIG. 12 is a flowchart for explaining a sequence of a subroutine “second release” of the camera of the present invention.

[Explanation of symbols]

1 ... Shooting mode setting section, 2 ... Selection section, 3 ... First AF operation mode, 4 ... Second AF operation mode, 5 ... Measurement number switching section, 6 ... Measuring section, 7 ... Photoelectric conversion section, 8 ... Arithmetic unit, 9
Defocus amount determination unit, 10 focus threshold variable unit, 11 focus determination unit, 12 AF operation mode setting unit,
13 ... Closed loop AF control mode, 14 ... Open loop AF control mode.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 13/36 17/28 E G03B 3/00 A

Claims (3)

[Claims] 1. A distance measuring means for detecting a phase difference amount of a subject image, a normal photographing mode for instructing a normal photographing screen size, or a trimming photographing for instructing a photographing screen size smaller than the normal photographing screen size. When the trimming shooting mode is set by the shooting mode setting means for setting any one of the modes, the mode is switched to the first AF mode in which the first number of times of distance measurement is designated, and When the normal photographing mode is set, AF mode switching means for switching to the second AF mode in which the number of times of distance measurement is smaller than that of the first AF mode, and the distance measuring means based on the output of the AF mode switching means. From the measured distance output, a calculation means for calculating the defocus amount of the photographing optical system or the distance to the subject,
A camera capable of switching a shooting screen size, characterized by being equipped with. 2. A distance measuring means for detecting a phase difference amount of a subject image from a light flux which has passed through a photographing optical system, a normal photographing mode for instructing a normal photographing screen size, or a normal photographing mode larger than the normal photographing screen size. A shooting mode setting unit that sets a trimming shooting mode for instructing a small shooting screen size, and a first shooting frequency setting unit that specifies the first number of times of distance measurement when the trimming shooting mode is set by the shooting mode setting unit. AF mode switching means for switching to the second AF mode in which the number of times of distance measurement is smaller than the first AF mode when the normal shooting mode is set, and the AF mode switching means. Defocus amount calculation means for calculating the defocus amount of the photographing optical system from the distance measurement output measured by the distance measurement means based on the output; Determination means for determining whether the output of the focus amount calculation means is within a predetermined value set in advance, and discarding the set number of times of distance measurement when it is determined that the defocus amount is not within the predetermined value. And a selection means for selecting either the first AF mode or the second AF mode based on the output of the defocus amount calculation means and outputting the selected AF mode to the AF mode switching means. A camera with a switchable screen size. 3. A camera which divides a subject image passing through a photographing optical system into two images and measures the light intensity distribution of each image to obtain the defocus amount of the photographing optical system from the interval between the two images. Shooting mode setting means for setting at least one of a normal shooting mode for instructing a range, a panoramic shooting mode for instructing a wider panorama range than the normal shooting mode, and a trimming shooting mode for instructing a narrow range, and two images. A photoelectric conversion unit that photoelectrically converts the divided subject image, a calculation unit that calculates a defocus amount based on the output of the photoelectric conversion unit, and a focus threshold variable that generates a predetermined focus threshold based on the selected shooting mode. And a focus determination means for determining whether or not the defocus amount is within the generated focus threshold. When either the panoramic shooting mode or the trimming shooting mode is set by the setting means, the focus threshold variable means has a focus smaller than the focus threshold of the second AF operation mode preset as the normal shooting mode. A threshold is generated, and the small focusing threshold is set to the first AF operation mode, and the focusing determining means compares the defocus amount with the small focusing threshold to determine whether it is within a predetermined range or not. If so, the camera is focused, and if it is outside the predetermined range, the defocus amount is corrected and the lens is driven.