JPH0215224A - Automatic focusing camera - Google Patents

Abstract

PURPOSE:To accurately follow and correct a lens driving amount with respect to a moving object by multiplying the changing speed of defocus quantity, which is caused by the move of the object, by time up to exposure and a prescribed constant corresponding to the direction of the changing speed, and thereby determining a correcting amount. CONSTITUTION:A focus detecting means 1 repeatedly detects the focusing condition of a lens affecting the object to be focused focuses it. The detected defocus quantities DFO are stored in a storage means 2 and focus detecting times are stored in a storage means 4. A lens position storage means 8 stores a lens position MIL at the previous detection time. Based on outputs from the focus detecting means 1 and the storage means 2, 4 and 8, a changing speed detecting means 5 detects the changing speed VHO of the defocus quantity, which is caused by the move of the object. A correcting amount determining means 6 multiplies the changing speed VHO by the time up to exposure and the prescribed constant, and determines the correcting amount DELTADF of the defocus quantity. Based on the defocus quantity DFO and the correcting amount DELTADF, a lens driving means 7 drives a focusing lens to a focusing position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic focusing camera that drives a focusing lens toward an in-focus position according to focus detection results, and It is particularly suitable for cameras.

[Prior Art] In conventional automatic focusing cameras, the focusing accuracy when photographing a dynamic subject is lower than the focusing accuracy when photographing a still subject. This is because if the subject is moving, even if the lens is driven to the in-focus position at the time of the current focus detection and the shutter is released, the subject will deviate from the in-focus position until the shutter is released. Therefore, JP-A No. 6 (>
As disclosed in Japanese Patent No. 214325, it has been proposed to perform tracking correction in which the lens is driven in accordance with the defocusing speed of the subject when the subject is moving. In this conventional example, the amount of tracking correction is determined by multiplying the defocusing speed of the subject by the time for performing tracking correction. Further, although the defocus speed of the subject is determined by the weighted average method, it is stated that it may also be determined by the quadratic curve approximation method.

[Problem to be Solved by the Invention] As described above, if the defocus speed is determined using the weighted average method, it should be possible to eliminate the variation in the detected defocus speed and accurately determine the defocus speed. However, this means that the past defocusing speed of the subject is accurately determined, and it does not mean that the defocusing speed of the subject when performing tracking correction is accurately determined. For example, when a subject approaches a photographer at a constant speed, the defocusing speed of the subject increases approximately in proportion to the square of time. For this reason, if the amount of tracking correction is determined based on the past defocus speed of the subject determined by the weighted average method, there is a problem that a tracking delay occurs. On the other hand, when the subject moves away from the photographer at a constant speed, there is a problem that the tracking correction amount becomes excessive.

Therefore, as suggested in the above-mentioned prior art, it is possible to calculate the defocus speed of the subject when performing tracking correction using the quadratic curve approximation method, but in this case, one speed calculation requires three steps. This requires multiple focus detections, complicates calculations, and causes tracking delays.

The present invention has been made in view of the above points, and an object thereof is to provide an automatic focusing camera with a simple configuration that can accurately follow and correct the amount of lens drive for a dynamic subject. be.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the automatic focusing camera according to the present invention, as shown in FIG. a focus detection means (1) that repeatedly detects the defocus DFO (defocus DFO); a focus detection means (2) that stores the amount of defocus detected by the focus detection means (1);
), a timekeeping means (3) for detecting the time when the amount of defocus is detected, a focus detection time storage means (4) for storing the output of the timekeeping means (3), a focus detection means (1), and a defocus scene. Based on the outputs of the storage means (2) and the focus detection time storage means (4), the change rate V of the amount of defocus due to the movement of the subject is determined.
The change speed detection means (5) detects the HO, and the change speed VHO detected by the change speed detection means (5) is multiplied by a predetermined coefficient depending on the time T until exposure and the direction of the change speed, and the dynamic The present invention is characterized by comprising a correction amount determining means (6) for determining a correction amount ΔDF for the amount of defocus caused by the subject.

In addition, a lens driving means (for driving the focus adjustment lens toward the in-focus position based on the amount of defocus detected by the focus detection means (1) and the correction amount determined by the correction amount determination means (6)) is provided. 7), and lens position storage means (8) for storing the lens position when the amount of defocus is detected by the focus detection means (1);
5) is the speed of change in the amount of defocus due to the movement of the subject VHO
The output of the lens position storage means (8) may also be used for the detection.

Further, the predetermined coefficient used by the correction amount determining means (6) is a coefficient larger than 1 when the speed of change in the amount of defocus due to the movement of the object or the direction in which the object is closer to the photographer; It is desirable to use a coefficient smaller than 1 when the subject is moving away from the photographer, and not to multiply by the predetermined coefficient when the speed of change is smaller than a predetermined speed.

However, FIG. 1 is an explanatory diagram showing the structure of the present invention functionally as a flock, and in the embodiments described later, "1"
The main part of the configuration described above is realized by a Microcombi J,-ta program. To show a specific correspondence, the focus detection means (]) is #1.07. in FIG. #],,13
In this figure, the defocus amount storage means (2) is located in #1-2 of the same figure.
The time measurement means (3) is located at #106, #], 08 in the same figure, the focus detection time storage means (4) is located at #109 in the same figure, and the rate of change detection means (5) is located at #313 in Figure 10. The correction amount determining means (6) are #401 to #409 in FIG. 12, and the lens driving means (7) are #35 in FIG. 11 and #4 in FIG. 12]
0. to #416, the lens position storage means (8) corresponds to #1]0 in FIG. 7, respectively.

1 action] Hereinafter, the operation of the present invention will be explained with reference to FIG.

The focus detection means (1) repeatedly detects the focus state of the photographing lens with respect to the subject to be focused, and outputs the amount of defocus (defocus DFO). The defocus DFO has a sign indicating the direction of defocus. This is a variable that indicates the absolute value or the magnitude of the defocus. The defocus amount storage means (2) stores the previous defocus LDF. Further, the focus detection time storage means (4) stores the previous focus detection time TMI-. Further, the lens position storage means (8) stores the lens position MI at the time of previous focus detection.
I remember L. The change rate detection means (5) detects the focus due to the movement of the subject based on the outputs of the focus detection means (1), the focus deviation amount storage means (2), the focus detection time storage means (4), and the lens position storage means (8). Change speed of deviation amount VHO
Detect.

Hereinafter, how to obtain the rate of change VI-10 will be explained.

In the figure, DFO is the current defocus, and LDF is the previous defocus. Moreover, MI is the lens position at the time of the current concave focus detection, and MII- is the lens position at the time of the previous focus detection. As a result, the defocus change δDF caused by the movement of the subject is δ DF=DFO−LDF
It is calculated as +(MI-MIL)/KL...■. DF O-y L DF is the change in defocus, and (M I - M I L)/igL is the defocus due to the movement of the lens during that time. However, K I- is a conversion coefficient between the lens drive amount and defocus. On the other hand, the time Δ1 required for the defocus change δDF to occur due to the movement of the subject is calculated by subtracting the previous focus detection time TMI- from the current focus detection time TM, and is calculated as follows: Δt: = T M - T M L
・It is calculated as ■. From formulas (1) and (2), the rate of change VHO is determined as VHO-δDF/ΔL.

The correction amount determining means (6) determines the correction amount ΔDF for the amount of defocus by multiplying this change rate VHO, the time T until exposure, and a predetermined coefficient. The predetermined coefficient is the rate of change V HO
It varies depending on the direction of the subject, and is set larger than 1 when the subject approaches. This prevents insufficient tracking. Further, when the subject is far away, the predetermined coefficient is set to be smaller than 1. This prevents excessive tracking.

Also, if the rate of change V ) (O is smaller than a predetermined speed, the predetermined coefficient is not multiplied. The lens drive means (7) detects the defocus D detected by the focus detection means (1-).
Correction amount △ determined by FO and correction amount determining means (6)
The focusing lens is driven toward the in-focus position based on the DF.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a single-lens reflex camera with interchangeable lenses, where 101 is a camera body and 102 is a zoom lens, which is an example of an interchangeable lens (taking lens). A main mirror 103 is composed of a reflecting part and a transmitting part. The light passing through the photographic lens is reflected by the reflection part of the main mirror 103, and is sent to the finder optical system (not shown).
A part of the submirror 10 is transmitted through the submirror 10.
41\ be guided. The sub mirror 104 is the main mirror 10
The light that has passed through B is reflected to the focus detection module 105. FIG. 3 shows the camera body 101 viewed from the front. As mentioned above, 101 is a main mirror of the camera body 103, 105 is a focus detection module, and 106 is a mechanical unit configured to automatically perform mirror up, exposure operation, film winding, and rewinding. Since these are not directly related to the present invention, their explanation will be omitted.

FIG. 4 shows a circuit diagram of a camera to which the present invention is applied. Reference numeral 201 is a camera control microcomputer that performs functions such as sequence control of the entire camera, exposure calculation control, and autofocus (hereinafter abbreviated as AF) calculation control, and has a data bus and various input/outputs as shown below. It includes terminals P1 to P21, etc. 202 is an AF distance measuring unit that measures the amount of defocus of a subject image, and includes a one-dimensional self-scanning image sensor (hereinafter abbreviated as CCD), a CCD drive unit, an A/D conversion unit, and a reference power source for A/D conversion. Consists of sources etc. Image information obtained by this CCD is taken into the CPU 201 via the AP device bus 201a. 203 is a display unit consisting of a liquid crystal display (LCD) or a light emitting diode (LED);
The display unit 203 displays information such as the shutter speed Tv and aperture value Av that are the calculation results of automatic exposure (hereinafter abbreviated as AE) sent from 01, as well as in-focus/out-of-focus, shooting mode, and the like. 204 is each interchangeable lens 1
A lens data circuit is provided in the camera body 101, etc., and stores information such as the maximum aperture value, the minimum aperture value, the focal length, and the electric conversion coefficient necessary for focus adjustment. Then, the data is transmitted to the camera body 1 via an electrical contact provided near the mounting part.
01. 205 is a photometry unit that measures the brightness Bv of the subject, which includes a photoelectric conversion element for light reception, an A/D conversion unit,
It is composed of a reference voltage source for A/D conversion, a data exchange unit with the CPU 201, etc., and measures the light that has passed through the photographic lens according to instructions from the CPU 201. A film sensitivity reading section 206 automatically reads the sensitivity of the loaded film, and the film sensitivity on the film cartridge is read through an electrical contact provided in the camera's camera chamber.

The display section 203, lens data circuit 204, photometry section 2
05, each piece of information from the film sensitivity reading unit 206 is input as a serial signal to the serial input/output unit 201c (abbreviated as serial I10 in the figure) via the serial data bus 201b. Reference numeral 207 is a sequence motor M3 for winding and rewinding the film, an AF motor M2 for driving the lens for AF, and a driver control unit for exciting various magnets required during exposure operation, and an output terminal P8 of the CPU 201. It is controlled by control output lines CMDO to CMD8 from P16. SW1~SW
3. SW5-5WIO are switches, one end of which is grounded, and the other end connected to input terminals P1-P7, P2O, and P21, respectively. SWI is a switch that turns ON when film charging starts and turns OFF when film charging is completed.SW2 is a switch that turns ON while the mirror is up and turns OFF when mechanical charging is completed.SW3 is a switch that repeats ON10FF multiple times while the film is running. be. SW5 is a photometry switch that is turned on at the first step of pressing down a shutter button (not shown), and the CPU 201 outputs a signal to start photometry and distance measurement. While this switch SW5 is ON,
If the lens is in an out-of-focus position due to distance measurement, the lens continues to be driven, and when it reaches the in-focus position, the lens stops driving, but the shutter button is released while the lens is being driven and the switch SW5 is turned OFF. If so, stop driving the lens. SW
Reference numeral 6 denotes a release switch that is turned on in the second step of pressing down the shutter button. When this switch SW6 is turned on when the release is possible, the CPU 201 issues a command for the release operation. In addition, the release switch SW
6 is turned on, the photometry switch SW5 is configured to be kept in the on state. SW7 is a film detection switch installed in the film travel path. When there is film at this film detection switch SW7, the switch SW7 is turned OFF, and when the film runs out, it is turned ON. , this switch S
When W7 changes from OFF to ON, it indicates that the film is slightly out of the Pa1 Herone, and is used as a switch for determining the end of rewinding. SW
Reference numeral 8 denotes a cartridge detection switch installed near the electrical contact of the film sensitivity reading section 206 provided in the cartridge chamber of the camera. When there is, it is ON state,
If there is no Pa1 Herone, it will be in an OFF state. SW9 is the back cover opening/closing switch, and turns O when the back cover is completely closed.
It becomes N. SWl,0 is a multiple exposure mode 1' switching switch, and when it is turned on, the multiple exposure mode will be activated.

RESET is set to control power supply voltage +vDD by resistor R1.
After the power is turned on, the content C1 is charged through the resistor R, and when the voltage changes from the "Lo" level to the "High" level, the CPU 20 ] or reset 6X is a crystal oscillator for providing a clock signal to the CPU 20.

Next, the driver control section 207 and each control section will be explained. ], CMFi has a macnet for holding one shutter curtain, and the control output line 1. When CMGO becomes Lou + "Luke, magnet l~1°CMg is energized,
One curtain of the shutter is held. 2CMg is Jack-2
There is a macnet for holding the curtain, and when the control output line 2CMGO reaches the 'LolI+' level, the macnet I-l
-2C is energized, the shack-2 curtain is held, and the above-mentioned 1
The time from when the curtain shutter is released to when the jack is released corresponds to the shutter speed.

FMg has pins 1 to FMg for locking the aperture of the photographic lens, and when the control output line FMG○ reaches the 'LoIII' level, the pins 1 to FMg are energized to hold and hold the aperture locking member. When released, the diaphragm locking member operates to lock the diaphragm in a predetermined position.RMFl is a release pin, and the control output line RMG○ remains at the "Lo4" level for a certain period of time. When this happens, the release member is unlocked, the diaphragm is narrowed down, and the mirror is raised.

Q] to QIO are 1-transistors for driving sequence motors M1 and A, and F motor M2. This sequence motor M1 has two types of coils inside, and can obtain the characteristics of high 1 to 1 herk low speed rotation and low 1 herk high speed rotation, and both characteristics can be switched, and both forward and reverse rotations are possible. 1 to transistors Q1 to Q6 are connected as possible. That is, the high-speed side terminal H of the J-ken smoke M1 is connected to the common connection point of the transistors Q1 and Q2, the low-speed side terminal is connected to the common connection point of the transistors Q3 and Q4, and the remaining common terminal C is connected to the transistor Q5. Each is connected to the common connection point of Q6. 1 Herancista Q in Table 1
Depending on the on/off status of 1 to Q6, Z-Kensmoke M
This shows how the rotational state of No. 1 changes.

Table 1 Note that in this embodiment, the high-speed brake is not used, and only the low-speed brake is used. Therefore, in the following description, the term "brake" refers to the low-speed brake SBR. Q7 to QIO are one half sister for driving the A and F motors M2, and are connected in a bridge configuration so that the AF motor M2 can be rotated in forward and reverse directions. A, F motor M
Step 2, rotate forward to extend the lens, and rotate in reverse to retract the lens. 0M1 to 0Ml0 are each transistor Q1 to Q],
This is a control output line for O switching.

211 and 212 are an aperture encoder and an AF encoder made of photocouplers, and input signal lines PTI and PT
2 is connected to the driver control unit 207. The aperture encoder 211 monitors the stroke of the aperture preset lever at the time of release, and the light emitted by the light emitting diode 211a is detected by the phototransistor 211 + at the time of release, and is input to the driver control unit 207 via the input signal line PT1. After being waveform-shaped into a pulse by this driver control unit 207, it is sent to the input terminal P18 of the CPU 201 via the output signal line FP. The AP encoder 212 is for monitoring the rotation speed of the AF motor M2 for driving the lens during AF, that is, the amount of movement of the lens, and the light emission from the light emitting diode 212a is detected by the phototransistor 212+1, and the input signal line PT2 is detected by the phototransistor 212+1. The signal is input to the driver control unit 207 via the driver control unit 207. After being waveform-shaped into a pulse by this driver control unit 207, it is sent to the input terminal P19 of the CPU 201 via the output signal line AFP. This output signal line AFP is connected to the CPU2
It is also connected to a counter 201d inside 01, and is used to monitor the extended position of the photographic lens. In other words, the counter 201d is 0 at the end of the lens (1).
By setting up count when driving in the near direction and setting count to town when driving in the ω direction, it is possible to obtain the number of pulses delivered from the ω end of the lens at any time. This AFP signal is transmitted to the interrupt terminal of the CPU 201 (
(not shown), and generates an interrupt at the falling edge of the AFP signal. In addition, the CPU 201 uses a timer 20
1e built-in, and is configured so that the time can be read by turning the internal clock. Furthermore, the CPU 201 has a built-in so-called E2PROM 20 if that can be electrically written to and read from and retains memory contents even when the power is turned off. Also, C.P.
U201 includes an interrupt timer (not shown) that generates a timer interrupt when a set time has elapsed.

Table 2 In the table, H is “for iHh’” level L means ``Loud'' level.

Table 3 In the table, H is ")(high" level L means 'Lou+' level.

CMDO to CMD8 are output terminals P8 to P of the CPU 20 to control the driver control unit 207;
6 is a control output line output from CMDO, CMD
I controls the control output lines RMGO and FMGO for RM g and FM & control to Macnet 1, respectively, and CMD2.
．． Macunet 1-1. respectively by CMD3. CMg,
2 Control output line for CM & control], CM GO2C
Control MGO. In addition, control output lines 0M1-0M6 for driving sequence motor M1 are connected by CMD4 to CMD6.
and CMD7. A, F motor M by CMD8
, drive control output lines ○M7 to ○M], O. Table 2 shows the control of the sequence motor M1, and Table 3 shows the control of the AF motor M2. In the table, H means "Hill level", and L means "Lou+Level".

AMg is a lock release mucket that moves the film still, and transistors Q11. CPU2 via resistor R2
01 output terminal P 1.7. The connection point between the heath of the transistor Q], ] and the resistor R2 is grounded via the resistor R3. The output terminal P]-7 of the CPU 201 is normally set to "Low", and one Heran sister Q1.1
Since it is in the off state, the magnets 1 to AMH are not energized and hold the suction piece by suction. In order to release the engagement between the winding stopper and the winding stopper lever, when the output terminal P of the CPU 201 reaches the Tig1 level,
The magnetic force is energized and the adsorption force is lost.

Next, a series of release operations in this embodiment will be explained with reference to FIG. As shown in the figure, the release operation is roughly divided into four sequences: mirror up, exposure, mechanical charge, and film charge.

In the mirror-up sequence, the main mirror sub-mirror is retracted, and the aperture of the photographic lens is disengaged to narrow the aperture. As for the exposure sequence, the exposure time (shutter speed 1~) is controlled by controlling the first and second curtains of the focal plane shutter. In the mechanical charge sequence, the main mirror, submirror, photographic lens diaphragm, and shutter curtain and second curtain are energized by a splash for the next release.

In the film charge sequence, the film is advanced.

This will be explained in more detail below using timer 1. As already explained in FIG. 4, the switch SW6 is
When the shutter button is pressed down two steps, it turns on and starts the release operation. When the release operation starts, first, the control output line RMGO is set to the "Lo" level to energize the release lenses 1 to RMg, which are urged by the spring. Unlock the main mirror. As a result, the main mirror is retracted to the finder side, and the submirror is also retracted in conjunction with the main mirror. Next, control output line FMG
By setting O to the "Low" level, electricity is applied to the lens 1 to FMg for locking the aperture, and the aperture of the photographic lens, which is biased by the spring, is released from the lock. When the lock is released, the aperture starts, and the state of the aperture at this time is determined by the monitor lens as explained in Fig. 4.
1-transistor 21], l) is inputted to the driver control unit 207, and the waveform-shaped FP multiplied signal is sent to the CP.
U20 ]. CPU 20] calculates a number of FP multiplication signal counts corresponding to the aperture value based on a predetermined exposure calculation;
By setting the control output line FM GO to the 'Hi) (h' level), the aperture is stopped and the photographing lens is set to the desired aperture value.Next, in order to perform the exposure operation, the 'Loud “The control output line IC that becomes the level
One of the control output lines 1. of MGO2CMGO. CMG
Set O to 'High'/\\.This causes one curtain of the focal plane shutter to run.After the exposure time according to the predetermined exposure calculation has elapsed, the other control output line 2
By setting the CM GO to "Tlight" Lenopel, two curtains of the focal plane shutter run and exposure control is performed. After exposure, a mechanical charge sequence begins. In the mechanical charge sequence, first, Since high torque is required when starting the motor, the motor is driven by the low-speed motor FF (L), and then, if the rotation speed does not reach a predetermined number, the motor is switched to the high-speed motor FF (H), which rotates from low 1 to high speed. As a result, the sequence motor M1 can be efficiently driven, and high-speed mechanical charging and film charging can be achieved.

This rotation of the sequence motor M1 causes the main mirror and submirror to move down and are biased by the spring, and at the same time, the aperture of the photographic lens and the first and second curtains of the focal plane shutter are also biased by the spring. When this mechanical charging is completed, as already explained, the switch SW2 is turned off as a mechanical charging completion signal. CPU
When the switch 201 detects that the switch SW2 is turned off, it shifts to the film charging sequence. This releases the lock that fixes the film and starts winding the film. At this point, the switch SWI for monitoring the film charge is turned on, and the film is wound by the Z-Kensmoke M. When film winding for one frame is completed, switch SWI is turned to O.
It becomes an FF and is notified to the CPU 201. CPU201
When it detects that the switch SW1 is turned off, it applies a brake (not shown) to stop the sequence mode M. This completes the release operation for one frame.

Next, the sequence during the snapshot mode in which the release is performed continuously while the switch SW6 is ON will be described, including the focus detection operation, with reference to the time chart shown in FIG. In FIG. 6, section ■ indicates the first frame of quick shooting, and section ■ indicates the second frame of continuous shooting. Section I of the first frame of the quick shot is as explained in FIG. By the way, in order to perform focus detection, it is necessary that the main mirror and submirror are lowered and stable. Therefore, the switch SW2 is turned OFF, and after the mechanical charging is completed and a period of time for mirror stabilization is waited, CCD integration is started. In this embodiment, this waiting time is set to 3Q+n5ec. The part marked 11 in the figure is the integration time of the CCD, and the part marked Dl is the CCD integration time.
It shows the data dump time for A/D converting the pixel data of and importing it into the memory of the CPU 201. When the pixel data of the CCD is taken into the CPU 201, reliability of defocus, defocus direction, and focus detection is determined by predetermined calculations. Since this focus detection calculation is not directly related to the present invention, a description thereof will be omitted. Now, when the first film charge is completed, the switch SW1 is turned OFF, and the sequence motor M1 is activated by the low speed brake S.
BR is applied.

At this point, the CPU 201 determines whether the switch SW6 is ON. If the switch SW6 is ON and the continuous shooting mode is set, then the second frame, which is indicated by section 3, starts to be released. In the case of this second frame, to release the film immediately after charging the film, in order to ensure that the film stops, wait for a while with the low speed brake SBR applied to the sequence motor M1, and press the release magnet RM.
g is energized. Now, if the result obtained in calculation 1 is that the camera is in focus, you can take an in-focus photo even if you release the camera next time with the photographic lens stopped, but if it is not in focus, you can continue to release the camera next time. For example, out-of-focus photos may be taken. In particular, when shooting in continuous shooting mode, there are many cases where the subject is moving and the defocus changes over time, so in calculation 1, the defocus due to the movement of the subject is Detect minutes. By driving the differential by 4 minus the difference while the mirror is up, it is possible to obtain a photograph in focus the next time the camera is released. A in Figure 6
The AF Momo-M2 column shows the driving state of the photographing lens by AF Momo-M2, and one line indicates the OFF state and the AFM
indicates that it is being driven in either direction.

To compensate for the defocus amount obtained as a result of calculation 1 or for the movement of the subject, the photographing lens is driven during mirror up in the next section (3). In addition, when the control output line RMGO is at Low level, that is, when the release magnets 1 to RMg are energized, the A
The power to F Momo-M2 is turned off. This is because the current flowing through the release magnet RMg is very large, and if the AF Momo-M2 is driven during this time, the A
Avoid problems such as the drive accuracy of F MOMO-M2 decreasing, or the current flowing to the release lens RM g decreasing, causing the mirror-up lock to be released and the mirror not being able to be raised. It's for a reason.

Thereafter, similarly to the first frame, the release is continued while switch SW6 is ON.

Next, the operation of this embodiment will be explained using flowcharts 1 to 1 shown in FIG. 7 and subsequent figures. The seventh country is flowchart 1~ when the above-mentioned photometry switch SW5 is turned on. When switch SW5 is OFF, the camera is in low power consumption mode, so-called sleeve mode. switch SW
When 5 turns ON, clock oscillation starts and is activated. When the CP [J 201 starts up, it sends a start signal and a clock to the peripheral IC in #101, and performs start-up processing such as initializing the boat. Next, in #102, flags, constants, etc. used in the program are initialized.

Subsequently, in step #103, the switches of each part of the camera body are checked, and serial communication with the flash, lens, display element, etc. is performed. Further, in order to discharge unnecessary charges from the CCD, which is a focus detection element, initialization is performed at #1o4.

Next, focus detection processing CD INTA (# 1.05
Proceed to (after). First, prior to the integration of CC[), #
At step 106, the integration start time is input into the memory TMI of the CPU 20 from the timer and saved.

Similarly, the counter is read without indicating the above-mentioned lens position, and safe is stored in memory T]. Thereafter, at #]07, CCD integration is performed to obtain a signal level suitable for focus detection. When the CCD integration is completed, the timer value is safed in the memory TM2 and the counter value is safed in the memory T2 at #108. Next, at #109, the memory TMr-
Safe the value of memory TM and save the value of memory TM (TM
Safe I-TMl)/2. TMI and TM2 indicate the integration start and end times, respectively, (TM2TM]
, )/2 means the time of the center of integration. Zunawaji #1
09 ('Memory the previous integration center time 'rM L
, the time at the center of the current integration is saved in the memory TM. Similarly, regarding the counter value, the memory M I 1. , , and safe the value of memory MI in memory MI. As described above, since the counter value corresponds to the lens position, TI, T2 indicate the lens position at the start and end of integration, respectively, and (T2-T1.)/2 indicates the lens position at the center of integration. That is, in #]10, the previous lens position of the center of integration is saved in MII-, and the lens position of the current center of integration is saved in MI.

Next, in #111, each pixel data of the CCD is sent to the CPU2.
Perform data stamping to input 01. Using this CCD pixel data, before starting the focus detection calculation, the value of the memory DFO is saved in the memory LDF in #112. At this point, the defocus DFO detected last time is stored in #107 (Vine focus detection is not performed by the integration of CCD, so #1) and
This means that you are safe on F. In #113,
#]07 Focus detection calculation is performed based on the integrated CCD pixel data, and the defocus DFO and defocus direction of the photographing lens as well as the reliability of focus detection are calculated.

Subsequently, in #1]4, serial communication and exposure calculation are performed, and photometric values are displayed and each switch is sensed. For example, if switch SW5 is turned off between #107 and #114, it is detected in #114, the display is turned off, the motor is turned off, etc., and the state returns to the sleeve state. When serial communication and exposure calculation are completed, #]15
Proceed to , and check the flag V L to determine whether or not you are currently taking snapshots.
It will be held at YF. This continuous shooting flag ■L )' F
is set to 1 if the photographer selects continuous shooting mode I during the winding -F (described later) operation.The continuous shooting flag is set to 1 by the determination in #115. If VL Y F is 1, the flow branches to continuous shooting ΔI"(#30). Flowcharts 1 to 1 of quick shooting AF will be explained in detail later using FIG. 10.

Now, if the snapshot flag VL)'F is O, #1
]61\, and it is determined whether or not the camera is in focus. This focus determination is determined to be independent if the reliability of focus detection in #]13 is higher than a predetermined value and the defocus DFO is smaller than a predetermined amount. The predetermined amount in this case is set to 100 μm. In addition, this value takes into account the depth of focus from the aperture value of the photographic lens set by exposure calculation, and is calculated as 60 μm + 8 X (2j!ogz
FNO+1) may be set. Here, FNo is the F number of the aperture value.

In addition, this predetermined amount is the E2P of the CPU 201 explained earlier.
It is written in the ROM 201f. This makes it possible to write small values for users who want high precision, and large values for users who want feel and focusing time, allowing us to respond to users in detail.

If focus is determined in #116, proceed to #117,
Focus is displayed. After in-focus display, exposure recalculation and serial communication are performed. This is done in order to reflect the focus detection result in the exposure calculation. Thereafter, the process waits while performing serial communication in #120 until the ON state of the switch SW6 is detected in #119.

If it is determined in #116 that the focus is not in focus, #121
The process proceeds to the subsequent out-of-focus processing 0UTFS.

First, in #122, the focus display is turned off, and then in #123, as a result of the focus detection calculation, if it is determined that the focus detection result is unreliable and cannot be used, that is, it is determined that the focus is low, the AF mode is turned off.
In order to perform the next focus detection without driving M2,
The process branches to focus detection processing CD-NTA after #105. If the contrast is not low, proceed to #]24 to start driving the AF Momo-M2, wait until the drive is finished in #125, and then select the focus detection processing CD from #105 onwards to perform the next focus detection. Proceed to TNTA. In #124,
The number of drive pulses ERRCNT for the AF momo-M2 described above is calculated by multiplying the defocus DFO by the conversion coefficient KL obtained from the photographing lens.

In other words, the number of drive pulses ERRCNT is ERRCN T
= Determined by DFOXKL. #125
Now, ARP for monitoring the rotation of AF Momo-M2.
AF until the signal is detected for the number of drive pulses ERRCNT
Momo-M2 is driven. Note that this conversion coefficient L differs depending on the focal length of each photographic lens, and is sent from the photographic lens through serial communication. Then again,
The same process is repeated until focus is determined from #105 to #116.

Next, a description will be given of the processing after the ON of the switch SW6 is detected in #119. At #126, it is determined whether the number of drive pulses ERRCNT is smaller than the constant NP1 written in the aforementioned E2PR○M2O1f (#126). The number of driving pulses ERRCNT is a constant NP
If the number is greater than I, a constant N is added to the drive pulse number ERRCNT.
Please reset PI #127>, drive pulse number ER, RC
If NT is smaller than the constant NPI, leave it as #1
Proceed to 28. In #128, it is determined whether the defocus DFO determined to be in focus in #116 is smaller than the constant DFC1. If DFO<DFCl, the process branches to release (#131) to immediately perform a release operation. If DFO≧DFC1, the process advances to #129, and it is determined whether the number of drive pulses ERRCNT is smaller than 4 pulses. If the drive pulse number ERRCNT is smaller than 4 pulses, the process immediately branches to release (#131). If the number of driving pulses ERRCNT is 4 or more pulses in #12, driving of the AF momo-M2 is started in #130. In the processes from #126 to #131, it is determined whether or not to drive the photographing lens during mirror up.

As already explained, in #116, focus is determined based on whether the detected defocus is within a predetermined defocus range. If this focusing range is shifted by a very small amount, accuracy will increase, but it will take time to achieve focusing due to variations in focus detection, camera shake by the photographer, etc. Alternatively, problems such as small hunting of the photographic lens may occur. Furthermore, if the object is a moving object, the detected defocus changes moment by moment, so no focus determination is made. For this reason, this focusing range is set to be wide enough to absorb variations in focus detection or changes in defocus due to changes in the subject. However, in this case, the defocus for the in-focus range remains as an error. For this reason, this remaining defocus is used during mirror up to create an even more accurate autofocus camera. In addition, in order to shorten the time until release, the number of pulses that can be driven during mirror up is limited to a constant NPI (#1.26, #127),
If sufficient accuracy is ensured, then #128D
If FO<DFCI, or if the number of drive pulses ERRCN T is less than 4 in #12, A
The drive accuracy of F Momo-M2 is also taken into account, and the release is made immediately.

Next, using FIG. 8, a series of release controls (#20 and subsequent steps) including mirror up, exposure time control, mechanical charge, fill and wind will be explained. first,
In #202, flags R and M G○NF are set to 1, indicating that the release pins 1 to R, Mg are being energized, and in #203, the AF MOMO-M2 is energized to 0FFL,
At #204, move the release magnet l-RM& and the shutter curtain holding magnet 1. CMg and 2CMg are energized. After that, after waiting time in #205, turn off the power to the release Macnet RMg in #206.
, #207 and clears the flag RMGONF to O. Through the processing from #204 to #206, the main mirror submirror is locked or released, and mirror-up is started. Further, by the processing in #202, #203, and #207, energization of the A and F motors M2 is prohibited while the power is being energized to the McNell-RM g. Specifically, AF Momo-M2 is controlled by turning on AF Momo-M2 by a timer interrupt that occurs at predetermined time intervals, and by applying a brake by interrupting the A and FP signals. flag R
When MGONF is 1, both the ON and brake of A and F motors M2 are prohibited, and the A and F motors M are turned OFF.
It is said that

When the flags R and MGONF are reset, the AF mode M2 is automatically restarted by a timer interrupt. The second process is to release magnets 1 to RM g.
A large current is required to energize the AF Momo-M2. be exposed.

When mirror up is started, then in #209, the magnet I-F M g for stopping the aperture is energized.

As a result, the diaphragm of the photographing lens is unlocked and the aperture starts to be stopped down. At #210, the pulse of the aperture encoder 2]1 described above is turned on, and when the pulse set by the exposure calculation is divided, at #21] the magnet FMg is de-energized and the aperture is fixed. . After this, at #212, release magnet RMg
Wait for a predetermined time t1 to elapse from energization to #21
Proceed to step 3. #213 In order to prevent the photographic lens from being driven during exposure, turn off the power to AF MOMO-M2 to 0FFL, and then set #2]-4 to turn off the power to AF MOMO-M2.
Turn off. As already explained, the sequence motor M+ is turned off at #214 after the second frame of continuous shooting.
The brakes are applied until the

#2] Shutter at 5] Makunetsu 1- for holding the curtain],
By turning off the power to CMg, one curtain of the physical plane shutter runs, waits for the shutter speed in #216, and attaches a holding magnet 2U to shutter 2 in #217. Turn off the power and run the second curtain of the focal plane shutter. This completes the exposure. In #218, the timer (safe in the memory TIMEI) is set for a predetermined time L1 in order to wait for the second act of Calplane shutter to complete.
Wait for 8 to pass and wind up as routine (#220)
Move to.

In the winding routine shown in FIG. 9, first, in #221, sequence motor M1 is energized to low speed motor 1, and #
After waiting for a predetermined time until the rotational speed of the motor M1 increases in step 222, the high speed mode is energized in step #223. As a result, the mechanical charging progresses, and the process waits until the switch SW2, which is the mechanical charging completion signal, turns OFF at #224.

When the switch SW2 is turned OFF and the mechanical charge sequence is completed, the main mirror and submirror are down, so TTI-photometry is possible, and photometry is started at #225. In order to proceed to the film charging sequence, as described above, the stop canceling pins 1 to AMg that keep the film still are energized for a predetermined time t6 (#226).

Thereafter, the process waits for a predetermined time too (#227), and then moves to #228. This predetermined time L1o is set to 30 m5ec in this embodiment, and is a waiting time for stabilizing the submirror. In #228, it is determined whether the continuous shooting mode has been selected by the photographer, and if it is the quick shooting mode, in #229, the continuous shooting flag VLYF is set to 1 without indicating that quick shooting is in progress. After setting, in order to perform focus detection next time, focus detection processing C after #105
Proceed to DINTA (#230). On the other hand, if the snapshot mode is not activated, #
After waiting at 231, focus detection processing CD after #105
Proceed to INTA.

The automatic focus adjustment operation during quick shooting will be explained using the flowchart shown in FIG. #1 from #230 in Figure 9
After proceeding to the focus detection process CDINTA from 05 onwards, focus detection calculation and exposure calculation are performed as explained in FIG. 7, and the process branches to continuous shooting AF (#301) at #115. Next, at #302, exposure calculation and serial communication based on the photometric values started at #225 in FIG. 9 are performed.

This makes it possible to always obtain appropriate exposure even if the subject brightness changes during snapshot shooting. Subsequently, in #303, the process waits until the switch SWI is turned off. That is,
Focus detection during film charging is limited to one time. This is to prioritize the next release since it is a quick shooting mode.

When the OFF state of the switch SWI is detected, the film charging sequence is completed, and the brake is immediately applied to the Z-ken smoke M1 at #3o4. In #306, it is determined whether the time required to wind the film is longer than a predetermined time. Film winding time varies greatly depending on the tension of the film, power supply conditions, number of frames, etc. If it is determined in #3.6 that the film winding is slow, then in #307 the following mode flag (TF, first time following flag T) and STP are reset to 1-1, respectively. The following mode 1' flux TF will be explained later, but when the subject is a moving object, it is set in the following mode to correct the movement of the subject. When it is determined in #306 that the film winding is slow, the interval between snapshots is long and an error occurs in the correction of the subject's moving bones, so the tracking mode flag T is set.
Resetting F.

In #308, it is determined whether the focus detection result is low contrast. If there is no low contrast, the process branches to #309 and the previous ignore flag LIF is reset. This previous ignore flag LIF is set when the next release is performed while ignoring low contrast during quick shooting. Next, in #310, VHO is stored in VHI as the previous defocus speed (velocity at the image plane of the subject), and in #313, the current defocus speed VHO is stored in VHI.
seek.

The calculation of the defocus speed VHO in #313 is performed as follows. At the time of #313, the current focus detection result is stored as a defocus DFO. By the process #112 in FIG. 7, the previous focus detection result is safe in the memory LDF. In addition, the lens position at the center of integration of the CCD that obtained the defocus DFO is stored in the memory MI by the process #110 in FIG.
The lens position at the center of integration of the CCD that calculated the previous defocus LDF is safe in the memory MIL. As a result, the defocus change δDF caused by the movement of the subject is as follows: δDF=DF(>LDF-(MI-MIL)/KL...
・It is calculated as ■. DFO-LDF is the change in defocus, and (M I - M I I-)/KL is the defocus due to the movement of the lens during that time. On the other hand, the time ΔL required during that time can be determined by subtracting the previous integration center time from the current integration center time.

From the process #109 in FIG. 7, Δt=TM−TML·■ is calculated. From equations (1) and (2), the subject speed VHO is determined as VHO-δDF/Δt.

After determining the subject velocity VHO in #313, the process proceeds to #3]9. On the other hand, if it is determined in #308 that the low contrast is l-, the process advances to #311. #3] At 1°, determine whether the previous ignore flag LIF is 1 or O,
If it is cleared to 0, proceed to #31.2/\, set the previous ignore flag l-I l'', set the current detected defocus DFO to 0, and set the drive pulse number ERRCNT to 0.
Set. #31], the previous ignore flag LIF
If it is set to 1, the release routine O of #3]4
UTR.

Branch to V2 and set the tracking mode flag TF at #3]5.
After that, the tracking initial flags Tl and STF, which will be explained later, are reset, respectively, and the continuous shooting flag VLYF is cleared in #317, and then the process jumps to UTFS in #121 in FIG. 7 (#318). As described above, when low contrast l~ is detected twice in a row during focus detection during quick shooting by the process of #308 to #3]8, continuous shooting mode 1~ is canceled and the release operation is prohibited. , again according to flowchart 1~ explained in FIG. 7, release is prohibited until focus is achieved.

As a result, in the case of a moving subject, it is possible to take a picture of the subject out of the focus frame during quick shooting, or the contrast can be taken at least once, and the probability of missing a so-called dramatic moment is greatly reduced. Furthermore, the probability of significant defocusing is low. In particular, in continuous shooting mode, there are many cases where the photographer wants to give priority to the release, so the effect is great. However, if low-contrast I is detected twice in a row, continuous shooting will be interrupted until the camera refocuses, so the release will not be performed continuously with a large amount of defocus. , when the photographer is careless and shoots an unintended subject, or when the front of the photographic lens is covered by a hand.
s, I: Even in such cases, the film is not wasted. In #312, since this time is low contrast 1 to last, defocus DFO, drive pulse number E RR
CNT or undetermined. Therefore, each of these is set to ○. Also, the defocus speed V l
(Since O cannot be calculated, it will not be updated.

That is, the previously detected defocus speed VHOR is used. Subsequently, in #319, it is determined whether the mote is currently a following mote. If the tracking mode flag TF has been reset and the tracking mode is not 1 to 3, #3
20, compare the defocus speed V H O obtained in #313 with the constant VE1, and find that VHO>VEI
In the case of #32], set the constant FZREL] to the focusing range INFZ, and in the case of V H O≦VE], set the constant FZREL] in #32].
At step 22, the constants FZREI-2 are respectively set. F Z R E L] is F Z R E L
It is set narrower than 2. That is, when the defocus speed V H O is small, the subject is stationary, and in this case, the change in defocus due to movement of the subject is small, so a wide focusing range is set and the defocus speed V
If H O is large, the defocus change is large, so a narrow focusing range is set. It is possible to take pictures at high speed,
When the defocusing speed V H O is higher than the predetermined speed VEI, a narrow focusing range is used, thereby realizing highly accurate snapshots with little tracking delay. In addition, these constants VE], FZREL1, FZREL2
are written in the E2PROM 201,f in the CPU 20, and can be rewritten according to the photographer's preference. In #323, the focus range INFZ set in #321 and #322 is compared with the currently detected defocus DFO. If the defocus DFO is smaller than the focusing range INFZ, it is determined that the accuracy is sufficiently high, and the process proceeds to #370, where it is determined whether the switch SW6 is ON. If the switch SW 6 is ON, the photographer has requested the next release, and the process jumps to the next release (#37). In other words, since the accuracy is ensured, the next release is performed without driving during mirror up. If switch SW6 is OFF, #372
Branches to subsequent release processing OUTRV, #373, #37
4, the continuous shooting flag VL)'F, and the following initial flag T1. After resetting the STF, the process jumps to focus detection processing CD INTA after #]05 in order to perform the next focus detection (#375).

On the other hand, in the judgment of #323, the currently detected defocus DFO
If the value is greater than or equal to the focusing range INFZ, the process advances to #324 to determine whether the photographic lens is driven or in tracking mode. In #324, it is determined whether the subject brightness is bright or dark. Specifically, the determination is made based on the integration time of the CCD and the gain multiplied by the output data, and if it is dark, the process branches to #333. If it is bright, the process proceeds to #325 and calculates the image magnification β of the subject. In #326, it is determined whether the image magnification β is larger than the constant BETALOCK. If β>BETAL OCK, the process branches to #333. β≦BETA L OC
In the case of K, proceed to #327 and set the defocus speed V.
Determine whether HO is greater than the constant RVMIN. If VHO≦RVMIN, branch to #333,
If VHO>RVMIN, the process advances to #328. #3
28, the defocus speed VHO is compared with the constant RVMAX.

If VHO≧RVMAX, branch to #333 and VHO
HO (For RVMAX, proceed to #329. #32
In step 9, it is determined whether the current and previous defocusing speeds VHO and VHI obtained in steps #31o and #313 are in the same direction or in opposite directions, and if they are in opposite directions, the process branches to #336. If they are in the same direction, proceed to #330. In #330, it is determined whether or not the follow-up first flag Tl and STF are set to 1. If they are cleared to 0, the process branches to #335 and is set to 1. If so, set the tracking mode flag TF to 1 in #331 to Sera 1, and execute the tracking processing routine RN.
Jump to AFTI.

Through the processes from #323 to #332 described above, a tracking mode for correcting the change in defocus due to the movement of the subject is determined. That is, if it is determined in #324 that the subject is dark, the CCD integration takes time and the noise component is large, so the defocusing speed VHO cannot be determined accurately, so the tracking mode cannot be entered. Also, #3
If it is determined in step 26 that the image magnification is large, the tracking mode cannot be entered in the same way because the influence of camera shake of the photographer is large. #327 Defocus speed■HO is constant R
If the value is less than VMIN, it cannot be determined whether the defocus change is caused by variations in focus detection or the like or by movement of the subject, and the tracking mode is not entered in order to avoid erroneous correction. Even if the defocus change occurs due to the movement of the subject, the speed is slow, so the defocus change is small and can be ignored even without correction.

If it is determined in #328 that VHO≧R, VMAX, the defocus change is abnormally large and cannot be considered to be a movement of the subject, but it is determined that the subject has changed, that is, the camera has been shaken, and the following mode is not set. does not enter. If the directions of the previous and current defocus speeds VHI and VHO are reversed in #329, it is thought that the focus detection is unstable or the subject is moving irregularly, and there is a high possibility that incorrect correction will be made. I can't enter it. Furthermore, #330, #331, #3
By performing the process of 35, the tracking mode is entered when the determination conditions of #323 to #329 are passed twice in succession. This makes it possible to reliably determine whether or not the subject is a moving object, and there is no risk of erroneous correction. Also, the constant B E
TALOCK, RV MIN, RV MAX
is E2PROM201F built in CPU201
is written in. #32 defocus speed VH
If the direction of O is reversed, especially unstable focus detection or subject movement is expected, so proceed to the cancellation process after #33G ○UTRV3, and set the tracking mote flag TP and tracking initial flag in #337 Tl5TF, reset the continuous shooting flag VLYF, and set # to perform the next focus detection.
Jump to focus detection processing CDINTA after 105 (8338). As a result, the next release will be prohibited,
As explained in FIG. 7, since the lens is driven until it comes into focus again, there is no need to worry about out-of-focus photography.

If it is determined in #324, #326, #327, #328, and #330 that the process branches to #333, the currently detected defocus DFO is compared with the constant INF'ZE1. In the case of DFO<INFZEI, the defocus is not very large and the focus detection is highly reliable, ensuring sufficient accuracy even if the photographing lens is driven during the mirror-up period and the next release is performed. Therefore, the process branches to a drive routine RNMTR during mirror up. DFO≧INFZE], the defocus is large, and if you release it the next time as it is, the accuracy may not be secured, so cancel processing OUT RV
2 Heshyump (#334.). #333, #334
By performing this processing, when the defocus is small, the mirror is raised while driving to achieve highly accurate automatic focusing and high-speed snapshots, and when the defocus is large,
- Detects the transformation point and focuses / Highly accurate automatic focusing is achieved.

Also, if the defocusing process ○UTFS is entered after the release process OUT RV 2 from #334, the lens is driven by the defocus DFO obtained during continuous shooting this time, as explained in Fig. 7. It is fast and accurate because refocusing is performed after Also, the constant INFZEI is CPU2014)
It is written in the E2PROM20 If, and can be changed as desired by the user.

Now, the follow-up process RNAFTI executed by branching based on determination #31 or jumping from #332 will be explained with reference to FIG. First, in #340,
Determine whether the directions of the current and previous defocusing speeds V l (O, V H1) are the same. If the directions are different, the subject suddenly stopped, changed direction, or shook the camera. In this case, the process branches to #341, jumps to the cancellation process ○UTRV3/\, cancels the tracking mode, and performs the automatic focusing operation again. This allows highly accurate focusing without making erroneous corrections even when the subject suddenly stops, changes direction, or shakes the camera.

If they are in the same direction, proceed to #342 and (Vl
(0-1-V)-11)/2 as constant A V E S H
Compare with. (VHO+VI-(1)/2 is #310
From the processing, G is shown and becomes a weighted average value. In the above equation, ■1 is the number of loops, and V Hi indicates the speed of the previous loop.

That is, #342 is the weighted average value and constant AVES H
Compare with. If the weighted average value is less than or equal to the constant AVESH, the weighted average value is reset to the defocus speed VHO in #343, and if it is greater than the constant AVESH, the process directly proceeds to #344. In other words, at low speeds, by performing weighted averaging, it is possible to achieve stable correction that absorbs fluctuations in focus detection,
In the case of a subject approaching the subject, the change in defocus increases approximately in inverse proportion to the square of the distance, so in the case of high speeds, correction with good responsiveness and little tracking delay is realized. Note that the constant AVESH is written in E2Pr (0M20 if) built in the CPU20.

#344 Calculate the image magnification β and use the constant B ETALO
Compare with CK2. As the image magnification increases, the influence of camera shake increases as described above, so the canceling process 0UTRV2 hejump is performed in #347, and the tracking mode is also exited.

In addition, the constant BETAL OCN3 is CPU20
1's E 2P ROM 20], f, and is set larger than the constant BET A, LOCK. #345 Tefkas speed V)
Compare I O and constant RVOUT, and determine the defocus speed V
If the speed is within HO or R, VOUT, the defocusing speed is sufficiently slow and the process branches to #347 to avoid erroneous correction due to fluctuations in focus detection. #346,
Compare the defocus speed VHO and the constant RV M A X 2. Defocus speed V HO is R, VMAX
2 or higher, it is determined that the defocusing speed is very fast and that even if follow-up correction is performed, there will be a delay or large defocusing, and the process branches to #347. At #347, the release process ○UTR, V2/\ jumps, cancels the following mode 1~, prohibits the next release, and performs focus detection again. As a result, in the case of a very high-speed subject, the shutter release is prohibited, and it is possible to prevent the camera from taking photos that are delayed. #3
The processes of #44 to #346 prevent erroneous correction and achieve highly accurate correction.

Subsequently, follow-up correction calculation 1 is performed in #348 to calculate the number of drive pulses ERRCNT. This calculation will be explained in detail later using FIG. 12. In #34, the defocus MDF after tracking correction is compared with the constant INFZE2. If the defocus after tracking correction is large, the process branches to #350 and jumps to the cancellation process 0UTRV21 from #316 onwards (FIG. 10) in order to improve accuracy.

As a result, only the continuous shooting flag VLYF is cleared, the tracking mode is maintained, and the out-of-focus processing is shifted to 0UTFS. Constant INFZE2 is E2PROM2 of CPU201
It is written in 01F. Also, this constant INFZE
2 is set larger than the constant INFZE1 explained in #333. This is because tracking correction is performed, and unless the correction amount is large, the process cannot proceed to #351.

The steps after #351 are mirror-up drive processing, and #33
This is the branch from #3 or the flow from #349. First, in #352, it is determined whether the switch SW6 is ON. If switch SW6 is OFF, the next release is not requested, so the process branches to #363 and release processing 0
Jump to UTRV. Subsequently, in #353, the number of driving pulses ERRCNT and the constant NPI are compared. As explained in FIG. 7, the constant NP1 is the number of pulses that can be driven during mirror up. If the number of drive pulses ERRCNT is less than or equal to the constant NPI, it is possible to drive during mirror up, and the process branches to #359/\.

If the number of driving pulses ERRCNT exceeds the constant NPI, the mirror cannot be driven long enough during mirror up, so driving time is required before the next release starts.
The time required to drive the F Momo-M2 varies depending on the power supply conditions, characteristics of the interchangeable lens, etc. Therefore, if the time until the start of the next release is fixed at 4Qmsec, and the number of drive pulses ERRCNT is within 40m5ec and the number of pulses that can be driven during the next mirror up (constant NP2), the AF
Drive Momo-M2, drive pulse number E RR, CN
If T exceeds the specified constant NP2, refocus detection is performed. As a result, 40m5ec can be achieved even in moving body mode.
The tracking correction can be made accurately. Furthermore, even if you wait 4 Qmsec, the speed of snapshots from 3 frames per second will only drop to 2.7 frames per second, and the deterioration of the feel of snapshots will be minimal. moreover,
When the number of driving pulses ERRCNT exceeds the constant NP2, refocusing is detected, which solves the problem that the error associated with lens driving increases indefinitely.

If ERRCNT≦NPI in #353, the process advances to #354 and the tracking flag TF is determined. In #354, follow mode (if TF = 1>, follow correction calculation 2 for 40 m5ec is performed in #355, if TF = 0, skip #355, and in both cases, in #356, drive pulse number ERRC
Compare NT with constant NP2. Drive pulse number ERRCN
If T exceeds the constant NP2, the process branches to #364 and jumps to release processing 0UTRV2. #349, #3
If the next release is to be performed by driving during mirror up without performing focus detection again in the determination in step 56, it is determined that the camera is in focus, and the focus display is maintained. Next, AF with #357
Start driving Momo-M2, #358 and 4Q+n5ec
Wait for an amount of time. In #359, the drive of AF Momo-M2 is started in case it branches from #353, and in #36
The process advances to the quick-shooting release process RNRELESE after 0.

Since #361 is a quick shot, in order to completely stop the film, the camera waits for a predetermined time 111, and then jumps to the next release. As is clear from the above explanation, in the tracking mode, it is necessary to correct defocus changes due to the subject, so the next release is not performed while the photographing lens remains stopped.

Next, the follow-up correction calculations after #401 will be explained with reference to FIG. First, in #402, it is determined whether the current focus detection is on low contrast 1 Hellas 1 or not. If the contrast is not low, a correction time T is determined in #403.

The time of the current CCD integration center is saved in the memory TM. Subtract the value in the memory TM from the current timer value TC and add the mirror up time of 70+n5ec to calculate the deviation from the current integration center until the next exposure. I need time. In the case of low contrast 1 helast, proceed to #40/] to find the time T from the previous exposure time to the next exposure time. As explained in FIG. 8, the previous exposure time is saved in the memory TIME. Therefore, it is sufficient to subtract the value in the memory TTMEl from the current timer value TC and add 70m5ec. That is, #40
2 to #404, if low contrast 1 to last 1 has not been reached, calculation is performed based on the current defocus DFO, and in low contrast 1 to last 1, calculation is performed assuming that defocus was 0 at the previous exposure. .

Subsequently, in #405, the defocus speed V1. (For O, set the time T obtained in #403 or #404 above to 1 yen 1・(
Then, the correction amount ΔDF is calculated. Next, in #406, the defocus speed VI-10 is compared with the constant V. VI-10> V V H If the defocus speed is fast, it is determined in #407 whether the subject is close or far away, and if the subject is close, the correction amount △DF is
is multiplied by 1.25 (#408). As mentioned above, if the subject is approaching in the optical axis direction at a constant speed,
Since the defocus speed increases in inverse proportion to the square of the subject distance, when the speed increases, the defocus speed also increases during the time T determined in #403 or #404 above.

In order to correct this error, the correction amount △DF is set to 1.25.
It's doubled. When the subject is far away, the defocus speed becomes slow, so the correction amount ΔDF is multiplied by 0.75 (#4.09). Next, in #410, check the direction of the currently detected focus DFO and defocus speed VHO, and if they are in the same direction, the corrected defocus MDF will be DFO (ΔDF (# /), : +1-
). If the direction is different, in #412, the currently detected differential 4-cass DFO is compared with the correction amount ΔDF, and DFO≦△
If it is DF, use correction defocus MDF as △DF-DF
Set O to 1~ (#4.13). If DFO>ΔDF, the photographic lens must be driven in the direction opposite to the defocus speed direction, and this means that a large defocus is detected in the direction opposite to the differential speed direction. For this reason, pack lash error due to reversal of the photographic lens,
Alternatively, assuming abnormal movement of the subject, perform stack initialization in #414 and release process in #415 ○U
TT (by proceeding to V21, the next release is prohibited and refocusing is performed. #, 111, #4] When the corrected defocus MDF is found in 3, the defocus is converted to the number of pulses in #416. The coefficient KI- is set to 111・(
Return the number of driving pulses ER, RCNT to cell l-1 (#4.1.7).

This allows for highly accurate correction even when the subject is moving at high speed, and can be used for both approaching and receding subjects. Furthermore, as is clear from the explanation of FIG.
Even when low contrast 1 to last I are ignored once in #308 to #312, the correction for the movement of the subject is correctly performed.

Finally, timer interrupts and ARP interrupts will be explained.

FIG. 13 shows a timer interrupt processing routine for driving AF Momo-M2. The CPU 20 has a built-in interrupt timer (not shown) that generates a timer interrupt when a set time has elapsed. When a timer interrupt occurs, #5
At step 02, the interrupt timer ■T is reset. As a result, the interrupt timer IT automatically generates a timer interrupt if the set time elapses after the current timer interrupt occurs.

Next, in #503, the flag RM G ON F is determined, and if it is set, the Macnet RMg for release is set.
Since the power is being applied to the AF Momo-M2 as mentioned above,
Set it to FF (#505). If the flag RMGONF is set to reset 1, #504 sets the A and F motors M.
2 and returns (#506).

FIG. 14 shows an AFP interrupt processing routine that occurs when the ARP signal falls. When an AFP interrupt occurs, first, in #602, the drive pulse number ERRCNT is decreased by one. In #603, the number of driving pulses E RRCN T becomes ◯, and it is determined whether or not the driving of the AF momo-M2 is completed. Number of driving pulses E RR, CN T or O, A
, if the drive of F motor M2 has not finished (,l,
Proceeding to #604, the interrupt timer IT is reset.

At #605, flags RMG and ONF are checked.

If the flag RMGONF is set and the release magnet RMg is energized, A is set in #608.
Turn off F Momo-M2. If the flag RMGONF has been reset, the brake is applied to AF Momo-M2 in #606, and the process returns (#607). On the other hand, #6
If it is determined in step 03 that the driving of the AF momo-M2 has been completed, the process branches to #609, and the energization of the AF momo-M2 is turned off in #609. Subsequently, in #610 and #611, timer interrupts and AFP interrupts are inhibited, respectively, and the process returns (#607). As mentioned above, timer interrupt and AFP
The AF momo-M2 is driven by the interrupt, and the AF momo-M2 is controlled to be OFF while the release magnet RMg is energized.

[Effects of the Invention] In the automatic focusing camera of the present invention, the rate of change in the amount of defocus due to movement of the subject is multiplied by a predetermined coefficient corresponding to the time until exposure and the direction of the rate of change. Since the amount of correction for the amount of defocus is determined, there is an effect that tracking correction for dynamic subjects can be performed with high accuracy.Moreover, since it can be multiplied by a predetermined coefficient,
This has the effect of requiring less calculation time and preventing tracking delays.

The present invention also includes a focus detection means for repeatedly detecting the amount of defocus, a defocus amount storage means for storing the detected amount of defocus, and a focus detection means for storing the time at which the amount of defocus was detected. Since the rate of change in the amount of defocus is detected based on the output of the time storage means, it is possible to detect the rate of change in the amount of defocus by adding some storage means to a conventional autofocus camera. , which has the advantage of being easy to implement.

Furthermore, if a lens driving means that drives the lens according to the corrected focus detection result and a lens position storage means that stores the lens position at the time of focus detection are provided, it is possible to prevent focus deviation due to movement of the subject even while the lens is being driven. This has the advantage that the rate of change in quantity can be detected accurately and accurate follow-up correction can be performed.

Note that when the rate of change in the amount of defocus due to the movement of the subject is smaller than the predetermined speed, shifting the focus so that it is not multiplied by the predetermined coefficient can prevent the tracking correction error from increasing when the subject approaches. , when the subject moves away, unnecessary calculations can be omitted and the calculation time can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention, FIG. 2 is a side view of a camera as an embodiment of the present invention, FIG. 3 is a front view of the same as the above, and FIG. 4 is a block circuit diagram of the same as the above. 5 and 6 are operation waveform diagrams of the same as above, and FIGS. 7 to 14 are flowcharts showing the same operation as above. (1) is a focus detection means, (2) is a defocus amount storage means,
(3) is a clock means, (4) is a focus detection time storage means, (
5) is a change rate detection means, (6) is a correction amount determination means, (
7) is a lens driving means, and (8) is a lens position storage means. Figure Figure

Claims (4)

[Claims] (1) A focus detection means that repeatedly detects the amount of defocus of the photographic lens with respect to the subject to be focused on, a defocus amount storage means that stores the amount of defocus detected by the focus detection means, and a defocus amount stored by the focus detection means. a timekeeping means for detecting the time at which the amount of deviation is detected; a focus detection time storage means for storing the output of the timekeeping means; and a movement of the subject based on the outputs of the focus detection means, the focus deviation amount storage means, and the focus detection time storage means. and a change speed detection means for detecting the change speed of the amount of defocus due to the dynamic subject. An automatic focusing camera comprising: correction amount determining means for determining the amount of correction for the amount of defocus. (2) A lens drive means for driving a focus adjustment lens toward a focus position based on the amount of defocus detected by the focus detection means and the correction amount determined by the correction amount determination means, and a focus detection means. It further comprises lens position storage means for storing the lens position when the amount of defocus is detected, and the rate of change detection means includes the outputs of the focus detection means, the defocus amount storage means, the focus detection time storage means, and the lens position storage means. 2. The automatic focusing camera according to claim 1, further comprising a means for detecting a rate of change in the amount of defocus due to movement of the subject based on . (3) The correction amount determining means sets a predetermined coefficient larger than 1 when the rate of change in the amount of defocus due to movement of the subject is in a direction in which the subject approaches the photographer; 3. The automatic focusing camera according to claim 1, further comprising coefficient setting means for setting a predetermined coefficient to be smaller than 1 when the direction is the same. (4) When the rate of change in the amount of defocus due to movement of the subject is smaller than a predetermined rate, the correction amount determining means calculates the amount of correction for the amount of defocus due to the moving subject by multiplying the rate of change by the time until exposure. 3. The automatic focusing camera according to claim 1, further comprising means for determining.