JPH0215211A - Automatic focusing camera - Google Patents

Abstract

PURPOSE:To achieve required lens driving without considerably lowering continuous photographing speed and to secure focusing accuracy by inhibiting release in continuous photographing operation for a prescribed period after previous release is ended and driving a lens while the release is inhibited. CONSTITUTION:A focus detecting means 1 detects the focusing state of a photographing lens, and outputs a defocus quantity DFO. A lens driving means 2 drives a focusing lens toward a focusing position based on the output detected by the focus detecting means 1. A release control means 3 controls operation so that release is continued while it is currently carried out. In a continuous photographing mode, only with the lens driving when the mirror is faced upward required lens driving is not attained, whereby the release control means 3 inhibits subsequent release until a timer means 4 counts for a prescribed period after previous release ends. While the release is inhibited, a lens driving and controlling means 5 drives the lens.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic focusing camera that drives a focusing lens toward an in-focus position according to a focus detection result. It is particularly suitable for reflex cameras.

[Conventional technology] Conventionally, during a release operation, the release operation is performed continuously;
Autofocus cameras are commercially available that have a continuous shooting mode that can take multiple pictures per second.

In addition, in autofocus cameras equipped with such a continuous shooting mode, focus detection is always performed during continuous shooting to ensure the necessary focusing accuracy even if the subject moves during continuous shooting. It has been proposed to continue driving the lens toward the in-focus position based on the results.

[Problems to be Solved by the Invention] However, if lens driving and focus detection are performed without limit during continuous shooting, there is a problem that the continuous shooting speed decreases. Since the continuous shooting mode as described above is often used to avoid missing a so-called dramatic moment, it is desirable that the continuous shooting speed (number of frames taken per second) be as fast as possible.

The present invention was made in view of these points, and its purpose is to enable the necessary lens drive and ensure focusing accuracy without significantly reducing the continuous shooting speed. The purpose is to provide an autofocus camera.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following features:
As shown in the figure, in an autofocus camera having a continuous shooting mode in which the release operation continues continuously during the release operation, a focus detection means (1) detects the amount of defocus of the photographing lens with respect to the subject to be focused; lens driving means (2) for driving a focus adjustment lens toward a focus position based on the detection output of the focus detection means (1); and a release control means (3) for continuously performing a release operation;
A timer means (4) for timing a predetermined time; and a timer means (4) that prohibits the release control means (3) from performing the next release until the predetermined time has been counted since the end of the previous release, and the lens drive means (2) The present invention is characterized by comprising a release-inhibited lens drive control means (5) for driving the lens.

In addition, when the present invention is applied to a reflex camera, it is desirable that the lens drive means (2) drive the lens even while the release control means (3) is raising the mirror. It is also desirable to further include focus detection control means (6) for operating the focus detection means (1) during film winding.

Further, there is provided a moving object determining means (7) for determining whether or not the subject is a moving object based on the detection output of the focus detecting means (1), so that the moving object determining means (7) determines that the subject is a moving object. It is more desirable to provide tracking correction means (8) for correcting the amount of lens driving by the lens driving means (2) so as to offset the change in the amount of defocus caused by the moving object.

However, FIG. 1 is an explanatory diagram showing the configuration of the present invention in functional blocks, and in the embodiments described later, the main part of the above configuration is realized by a microcomputer program. To show a specific correspondence, the focus detection means (1) is #107 in FIG. #113, the lens driving means (2) at #359 in FIG. 11, the release control means (3) at #201 to #220 in FIG. 8, and the timer means (4) at #358 in FIG. , the lens drive control means (5) when the release is prohibited is at #357 in the figure, and the focus detection control means (6) during film winding is at the first CD INTA after #23o (up to #304), and the moving object determination means ( 7) corresponds to #329 in FIG. 10, and tracking correction means (8) corresponds to #401 to #417 in FIG. 12, respectively.

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

The focus detection means (1) detects the focus state of the photographic lens with respect to the subject to be focused, and outputs the amount of defocus (defocus DFO). Here, defocus D
FO is a variable whose sign indicates the direction of defocus and whose absolute value indicates the magnitude of defocus.

The lens driving means (2) drives the focusing lens toward the in-focus position based on the detection output of the focus detecting means (1). The lens drive control means (3) performs control so that the release operation continues continuously during the release operation. As will be described later, the release operation consists of four sequences: mirror up, exposure, mechanical charge, and film charge. When the subject moves little, the amount of lens drive is small, so it is desirable to drive the lens while the mirror is up to ensure focus accuracy. However, in reality, continuous shooting mode is used when shooting dynamic subjects. Although it is often used, it is not possible to perform the necessary lens drive only by driving the lens while the mirror is up. Therefore, the timer means (4
), a predetermined time (for example, 4Qmsec) is counted, and while the timer means (4) is counting time, the next release is prohibited, and while the release is prohibited, the lens drive control means (5) drives the lens. Then, the remaining lens driving is performed while the mirror is up. This allows the necessary lens drive to be performed without significantly reducing the continuous shooting speed. For example, if the lens driving time during release prohibition is 4Qmsec,
The continuous shooting speed of 3 frames per second should not drop to 27 frames per second (this is enough, and the deterioration of the continuous shooting feel is minimal. Also, the continuous shooting speed of 4 Qms
By providing an ec lens drive time, the range of dynamic objects that can be photographed continuously can be greatly expanded.

Note that during film winding, the focus detection control means (6) operates the focus detection means (1), so that the film winding operation and focus detection operation can be performed in parallel, so that the continuous shooting speed can be reduced. can be further improved. Further, as mentioned above, since the continuous shooting modes 1 to 1 are often used when photographing a moving subject, the moving object determination means (7) and the tracking correction means (8) are provided, and the motion determination means (7) are provided. ), if the subject is determined to be a moving object, the tracking correction means (8
) to find the correction amount ΔDF of the defocus DFO due to the movement of the subject, and the lens driving means (2) calculates the correction amount ΔDF by (D
Focusing accuracy can be improved by driving the lens by F + ΔDF).

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows a single-lens reflex camera with interchangeable lenses, where 01 is a camera body and 102 is a zoom lens, which is an example of an interchangeable lens (taking lens). ]03 is a main mirror, which is composed of a reflective 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).
At the same time, a part of the light is transmitted through the →knob mirror 1.04. The mirror 104 reflects the light transmitted through the main mirror 03 to the focus detection module 1.05. 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 A and F) functions. input/output terminals P1 to P2], 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);
It consists of a driving section, an A/D conversion section, a reference power generation source for A/D conversion, etc. The image information obtained by this CCD is A
The data is taken into the CPU 201 via the P data bus 201a. 203 is a display unit consisting of a liquid crystal display (LCD) or a light emitting diode (LED), and the CPU
The display unit 203 displays information such as the shutter speed Tv and aperture values A, v, focus/out-of-focus, shooting mode, etc., which are the calculation results of automatic exposure (hereinafter abbreviated as AE) sent from 201. . A lens data circuit 204 is provided inside each interchangeable lens 102 and stores the maximum aperture value, the minimum aperture value, the focal length, the extension amount conversion coefficient necessary for focus adjustment, and the like.
2 is attached to the camera body 101, the data is transmitted to the camera body 101 via an electrical contact provided near the attachment part. 205 is a photometry unit that measures the brightness Bv of the subject, and is composed of a photoelectric conversion element for light reception, an A/D conversion unit, a reference voltage source for A/D conversion, a data exchange unit with the CPU 201, and receives commands from the CPU 201. The light passing through the photographic lens is measured according to the following. 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 cartridge chamber of the camera.

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 driver control unit for exciting the Z-Kensmoke M1 for winding and rewinding the film, the AF motor M2 for driving the lens for AF, and various magnets required during exposure operation, and the output of the CPU 201. It is controlled by control output lines CMDO to CMD8 from terminals P8 to 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. SW1 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 0N10FF multiple times while the film is running. . SW5 is a photometry switch that is turned ON in 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 as determined by distance measurement, the lens continues to be driven, and when it reaches the in-focus position, the driving of the lens is stopped.
The shutter button is released while the lens is driving, and the switch S
When W5 turns OFF, lens driving is stopped. SW6
is a release switch that turns on in the second step of pressing down the shutter button, and when the release is possible,
When this switch SW6 is turned on, the CPU 201 commands a release operation. In addition, release switch SW6
When the switch SW5 is turned on, the photometry switch SW5 is configured to be kept in the on state. SW7 is a film detection switch provided in the film travel path. When there is film at this film detection switch SW7, the switch SW7 is OFF, and when the film runs out, it is ON. When rewinding, This switch SW
When switch 7 changes from OFF to ON, it indicates that the film is slightly protruding from the cartridge, and is used as a switch for determining the end of rewinding. SW8 is a cartridge detection switch provided near the electrical contact of the film sensitivity reading unit 206 provided in the cartridge chamber of the camera, and is turned ON when a cartridge is in the cartridge chamber and the back cover is closed. If there is no patrone, it will be in OFF state. SW9 is a back cover opening/closing switch, which is turned ON when the back cover is completely closed. SWI O is a multiple exposure mode selection switch;
When set to N, the mode becomes multiple exposure mode.

RESET is set to control power supply voltage +vDD by resistor R1.
This is a reset terminal that is pulled up to 0. After the power is turned on, the capacitor C1 is charged via the resistor R1, and when the voltage changes from the 'Lour' level to the 'Higl+' level, the CPU 201 is reset. It has become. X is a crystal oscillator for providing a clock signal to the CPU 201.

Next, the driver control section 207 and each control section will be explained. 1. CMg is a magnet for holding the first shutter curtain. When the control output line ICMGO reaches the "Lou+" level, the magnet ICMir is energized and the first shutter curtain is held. 2CMg is a magnet for holding the first shutter curtain. Macnet, and the control output line 2CMGO is “
I L ,,When it reaches I+ level, magnet 2C
Mg is energized, the second shutter curtain is held, and the time from when the first curtain shutter is released and when the second curtain shutter is released corresponds to the shutter speed. F
Mg is attached to magnet 1 for locking the aperture of the photographic lens.
When the control output line FMGO reaches L our''' level, the magnet FMH is energized and holds the aperture locking member, and when the holding is released, the aperture locking member operates and the aperture is held at a predetermined position. RMg is a magnet for release, and the control output line RMGO is connected to "Lou" for a certain period of time.
When it reaches the +“° level, the release member is unlocked, the aperture is narrowed down, and the mirror is raised.

Q1 to Q10 are transistors for driving the Z-Kensmoke M, A, and F motors M2. This Z-Kensmoke M1 has two types of coils inside, and can obtain the characteristics of high-torque, low-speed rotation and low-torque, high-speed rotation.It is possible to switch between both characteristics, and it is also possible to rotate in the forward and reverse directions of each. 1 to transistors Q] to Q6 are connected as shown in FIG. That is, high-speed side terminal 1 of sequence motor M1
1 is connected to a common connection point between transistors Q1 and Q2, a low-speed side terminal I- is connected to a common connection point between transistors Q3 and Q4, and the remaining common terminal C is connected to a common connection point between transistors Q5 and Q6. Table 1 shows transistors Q1 to Q6.
This shows whether the rotational state of the sequence motor M1 changes depending on the on/off state of the sequence motor M1.

(Margin below) 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 explanation, the term "brake" refers to the low-speed brake SBR. Q7~Q], O is for driving AF Momo-M, 1
The AF Momo-M2 is connected in a bridge configuration so that the AF Momo-M2 can be rotated forward and backward. AF Momo-M2
The lens is extended by rotating in the forward direction, and the lens is retracted by rotating in the opposite direction.

OM1~○M ], O is each 1-run sister Q1~Q
], is the control output line for the O switch link.

211 and 212 are an aperture encoder and an AP encoder made of photocouplers, and input signal lines PT], , P
It is connected to the driver control unit 207 by T2.

The aperture encoder 211 monitors the stroke of the aperture preset lever at the time of release, and at the time of release, the light emitted by the light emitting diode 211a is detected by the transistor 211b and input to the driver control unit 207 via the input signal line PTI. be done. 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 Momo-M2 for driving the lens during AF, that is, the amount of movement of the lens.
Light emitted by the light emitting diode 212a is detected by the phototransistor 212b, and is input to the driver control unit 207 via the input signal line PT2. Then, after being waveform-shaped into a pulse by this driver control unit 207, it is sent to the input terminal P19 of the CPU 20b 1 via the output signal line ARP. This output signal line AF
P is also connected to a counter 201d inside the CPU 201, and is used to monitor the extended position of the photographic lens. That is, the counter 201d is the lens ω.
Cleared to O at the end, up-currency I when driving in the near direction
By setting the down run to 1 or more when driving in the ω direction, the number of pulses extended from the end of the lens can be obtained at any time. This AFP signal is sent to the CPU 201
It is also connected to an interrupt terminal (not shown) of the ARP signal, and generates an interrupt at the falling edge of the ARP signal. Further, the CPU 201 has a built-in timer 201e, and is configured to be able to read the time by counting an internal clock. Furthermore, the CPU 201 has a built-in so-called E2PROM 201f that can be electrically written to and read from and retains memory contents even when the power is turned off. The CPU 201 also includes an interrupt timer (not shown) that generates a timer interrupt when a set time has elapsed.

Table 2 In the table, H is “High” level L means II+ level.

Table 3 In the table, H is l4iHh” level I am thinking of I L oll III level.

↑9 CMDO to CMD8 are control output lines output from output terminals P8 to P16 of the CPU 201 to control the driver control unit 207, and CMDO and CMDI are control output lines R for magnet RMg and FMg control, respectively.
Control MGO, FMGO, CMD2. CMDB controls control output lines ICMGO and 2CMGO for controlling magnets ICMg and 2CMg, respectively. Also, CMD
Control output lines OMI to OM6 for driving the sequence motor M1 are controlled by CMD7.4 to CMD6. Control output line OM7 to 0Ml for driving AF Momo-M2 by CMDB
Controls 0. Table 2 shows the control of the sequence motor M, and Table 3 shows the control of the AF momo-M2. In the table, H is '
"High" level, L means "Lou+ level".

AMg is a lock release magnet that holds the film still, and transistors Q11. CPU2 via resistor R2
01 output terminal P17. Transistor Ql
The connection point between the base of 1 and the resistor R2 is grounded via the resistor R3. Output terminal P17 of CPU2Ol is normally “”L
oul'' level and the transistor Qll is off, so the magnet AMH is not energized and holds the suction piece by suction.In order to release the engagement between the winding stop and the winding stop lever, the CPU 201 When the output terminal P17 becomes 'High' level, the magnet AMtr is energized and the attraction force disappears.

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. In the exposure sequence, the exposure time (shutter speed) is controlled by controlling the first and second curtains of the focal plane shutter. In the mechanical charging sequence, the main mirror, sub-mirror, aperture of the photographing lens, and the first and second curtains of the shutter are energized by springs for the next release.

In the film charging sequence, the film is advanced.

A more detailed explanation will be given below using time chart 1~. As already explained in FIG. 4, the switch SW6 has the following functions.
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 "Loud" level to energize the release magnet RMg and release the main mirror that is biased by the splash. As a result, the main mirror is retracted to the viewfinder side, and the sub-mirror is also retracted in conjunction with the main mirror.Next, connect the control output line FMGO to "Lou+
''' level allows the locking of the diaphragm to lock.
~ FMg is energized to release the diaphragm of the photographing lens which is biased by the spring. When the lock is released, the aperture starts to be narrowed down, but the state of the aperture at this time is input to the driver control unit 207 from the monitor photo transistors 211b and 1 to 1, and the waveform is The shaped FP multiplied signal is input to the CPU 201. The CPU 201 counts the number of FP times signals corresponding to the aperture value based on a predetermined exposure calculation, and connects the control output line FMGO to '
By setting the aperture value to "Hi'Hh" level, the aperture is stopped and the photographing lens is set to the desired aperture value.Subsequently,
To perform the exposure operation, among the control output lines ICMG0゜2CMGO that are at a 'Low' level at the start of release,
One control output line 1cMGO is set to 'Hi) (h' level. This causes the first 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 2CMGO is set to 'High' level. By doing so, the second curtain of the focal plane shutter runs and exposure control is performed.After exposure, the mechanical charge sequence begins.In the mechanical charge sequence,
First, since high torque is required when starting the Z-Ken Smoke M1, it is driven in low speed mode F (L), and then,
When the predetermined rotational speed is reached, the mode is switched to high-speed mode F(H) of low-torque high-speed rotation. This makes it possible to efficiently drive the sequence motor M1 and achieve high-speed mechanical charging and film charging.

This rotation of the sequence motor M+ causes the main mirror and the 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 20↑ detects that this 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, there is a switch SWI that monitors the film charge. N, and film winding is performed by the sequence motor M1. When winding of the film for one frame is completed, the switch SWI is turned off and the CPU 201 is notified. CPU20
1 applies a brake (not shown) to stop the sequence mode M when it detects that the switch SWI is OFF. This completes the release operation for one frame.

Next, the sequence in the continuous shooting mode in which the camera is continuously released while the switch SW6 is ON will be described with reference to the time chart 1 in FIG. 6, including the focus detection operation. Section I in FIG. 6 indicates the first frame of continuous shooting, and section ■ indicates the second frame of continuous shooting. The section I of the first frame of continuous shooting is as explained in FIG. However, in order to perform focus detection, it is necessary that the main mirror and sub-mirror are lowered and stabilized. Therefore, switch SW2 is turned OFF,
After completing the mechanical charge and waiting for a period of time for the mirror to stabilize, COD integration is started. In this embodiment, this waiting time is set to 30 m5ec. In the figure, the part not indicated by 1 is the integration time of the CCD, and the part not indicated by Dl is the CCD.
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 SWI is turned OFF, and the sequence motor M 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, in order 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 M, and release magnet RM.
g is energized. Now, if the result obtained in calculation 1 is in focus, the next time you release the camera with the photographic lens stopped, you will be able to take an in-focus photo, but if it is not a goldfish, then the next time you release the camera. If you do, you'll end up with out-of-focus photos. 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 performing this defocus drive while the mirror is up, it is possible to obtain an in-focus photograph even at the next release. 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 H. Further, when the control output line RMGO is at the 'I low I+ level, that is, when the release magnet RMg is energized, the AF momo-M2 is de-energized. 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 driving accuracy of the AF Momo-M2 will drop, or the current will flow to the release magnet RM&. This is to avoid the problem that the mirror may not be able to be raised because the current decreases and the lock for raising the mirror is released.

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

Next, the operation of this embodiment will be explained using the flowcharts from FIG. 7 onwards. FIG. 7 is a flowchart when the photometry switch SW5 mentioned above is turned on. When the switch SW5 is OFF, the camera is in a low power consumption mode, a so-called sleeve mode. When the switch SW5 is turned on, clock oscillation starts and is activated. C
When the PU 201 is activated, it sends an activation signal and a clock to the peripheral IC in #101, and performs activation processing such as initializing the boat. Next, in #102, flags, constants, etc. used in the program are initialized. continue,#
At 103, switches in each part of the camera body are checked, and serial communication is performed with the flash, lens, display element, etc. Furthermore, in order to discharge unnecessary charges from the CCD, which is a focus detection element, initialization is performed at #104.

Next, the process proceeds to focus detection processing CD INTA (#105 and subsequent steps). First, prior to CCD integration, #10
In step 6, the integration start time is input to the memory TMI of the CPU 201 from the timer and saved.

Similarly, the counter indicating the lens position mentioned above is read and saved in the memory T1. Thereafter, in step #107, CCD integration is performed to obtain a signal level appropriate for focus detection. When the CCD integration is completed, the timer value is saved in the memory TM2 and the counter value is saved in the memory T2 in #108. Next, in #109, save the value of the memory TM in the memory TML, and save the value of the memory TM in the memory TM (TM2
−TMl)/2. TMI and TM2 indicate the integration start and end times, respectively, and (TM2-TMI
)/2 means the time of the center of integration. That is, #10
9, the previous integration center time is saved in the memory TML, and the current integration center time is saved in the memory TM. Similarly, regarding the counter value, the memory MIL is set at #110.
Safe the value of memory MI and save the value of memory MI (T
2-T ], )/2 is safe. As mentioned above, the counter value corresponds to the lens position, so TI, T2
indicate the lens position at the start and end of integration, respectively, and (T
2-TI>/2 does not indicate the lens position at the center of integration.

That is, in #1-ko○, the lens position of the previous integration center is MIL, and the lens position of the current integration center is M
I have saved each of them.

Next, in #1]1, each pixel data of the CCD is sent to the CPU2.
0] performs a data dump. 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, focus detection by CCD integration in #107 has not been performed, so the process in #1]2 stores the previously detected defocus DFO in memory 1-D F
This means that it is safe. In #113, #
A focus detection calculation is performed based on the CCD pixel data integrated in step 07, and the reliability of the defocus DFO and defocus direction of the photographing lens as well as the focus detection is calculated. Subsequently, in step #114, serial communication and exposure calculation are performed, and photometric values are displayed and each switch is sensed.

For example, switch SW5 is turned off between #107 and #1]4.
When it becomes FF, it is detected at #]14, 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, #1-15
The flag V L is used to determine whether continuous shooting is currently in progress.
It will be held at YF. This continuous shooting flag LYF is set to 1 when the photographer has selected the continuous shooting mode during the winding operation, which will be explained later. This #11
If the continuous shooting flag (1) is set in step 5, the process branches to continuous shooting AF (#30) (7) 70-I\. The flow chart of continuous shooting A and F will be explained in detail later using FIG. 10.

Now, if the continuous shooting flag is V L Y F or O, #11
The process advances to step -6, and it is determined whether or not the camera is in focus. In this focus determination, if the reliability of the focus detection in #113 is higher than a predetermined value and the defocus DFO is smaller than a predetermined amount, it is determined that the focus is in focus. The predetermined amount in this case is set to 100 μmn. In addition, this value is 60 μm + 8X (2 fogz Frio + 1
) may also be set. Here, PNO 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 ROM201. 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, it waits while performing serial communication in #120 until it is detected in #11 that the switch SW6 is ○N.

If it is determined that the focus is not in focus in #116, #]21
The process proceeds to the subsequent out-of-focus processing 0UTFS.

First, the focus display is turned off in #122, and then in #]23, if it is determined that the focus detection result is unreliable and cannot be used, that is, the focus detection result is low, the AF motor M2 is driven. In order to perform the next focus detection without
The process branches to focus detection processing CD INTA starting from #10. If it is not low contrast, proceed to #124 and A
After starting the drive of F motor M2 and waiting until the drive ends in #125, in order to perform the next focus detection, start the drive with #105.
Subsequent focus detection processing CD I [Proceed to NTA. #124
Then, the defocus DFO is multiplied by the conversion coefficient KL obtained from the photographic lens to calculate the number of drive pulses ERRCNT for the AF motor M2 as described above.

In other words, the number of drive pulses ERRCNT is ERRCN T
= D F Ox K I-. #12
5 is an AF for monitoring the rotation of AF motor M2.
P signal is detected for the number of drive pulses ERRCNT A
F%-ta M2 is driven. Note that this conversion coefficient KL varies depending on the focal length of each photographing lens, and is sent from the photographing lens through serial communication. Then again,
The same process is repeated from #105 until focus is determined in #116.

Next, a description will be given of the processing after the ON of the switch SW6 is detected in #119. In #126, it is determined whether the drive pulse number ERRCNT is smaller than the constant NPI written in the E2PROM 201f (#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 the PI #127), drive pulse number ERR,C
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 in focus in #116 is smaller than the constant DFCI. If DFO<DFCl, the process branches to release (#131) to immediately perform a release operation. If DFO≧DFC1, the process proceeds to #129, and it is determined whether the number of drive pulses ERRCNT is smaller than 4 pulses. Drive pulse number ERRCNT is 4
If it is smaller than the pulse, release immediately (#131)
branch into. If the number of driving pulses ERRCNT is 4 or more pulses in #129, 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 step #116, focus determination is performed depending on whether the detected defocus is within a predetermined defocus range. If this focusing range is made very small, accuracy will increase, but it will take time to focus 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, when the subject 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 corresponding to the focusing range remains as an error. For this reason, the remaining defocus amount is used to drive the mirror during mirror up, thereby realizing an even more accurate autofocus camera b. Also, 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 #126. #127), if sufficient accuracy is ensured, that is, if DFO<DFCI in #128, or if the number of driving pulses ERRCNT is determined in #129
When is smaller than 4, the drive accuracy of AF Momo-M2 is taken into account and the shutter is immediately released.

Next, a series of release controls (from #201 onwards) including mirror up, exposure time control, mechanical charging, and film winding will be explained using FIG. First, #2
Set the flag RMGONF to 1, which indicates that the release magnet (RMg) is energized at #02, and
At #03, the AF MOMO-M2 is energized to 0FFL, and at #204, the release magnet RMg, the shutter curtain holding magnets ICMg and 2CMg are energized. after that,#
After waiting for a time at 205, the energization to the release magnet RMg is set to 0FFL at #206, and the flag R is set at #207.
Clear MGONF to O. Through the processes from #2b04 to #206, the main mirror sub-mirror is unlocked and mirror-up is started. Also,#
Magnet R by the processing of 202, #203, #207
While the Mg is being energized, the AF Momo-M2 is prohibited from being energized. Specifically, the control of AF Momo-M2 is such that AF Momo-M2 is turned on by a timer interrupt that occurs every predetermined time.
This is done by braking by interrupting the AFP signal, and when the flag RMGONF is 1, both the ON of AF Momo-M2 and the braking are prohibited.
AF Momo-M2 is turned off.

When the flag RMGONF is reset, driving of the AF momo-M2 is automatically restarted by a timer interrupt. The above process requires a large current to energize the release magnet RMg, and by energizing AF Momo-M2, the current flowing to the magnet RMg is insufficient, and the lock cannot be released and the mirror cannot be raised. This is done to prevent such inconveniences.

When the mirror-up is started, the magnet FMH for locking the aperture is subsequently energized in #209.

As a result, the diaphragm of the photographic lens is unlocked and the aperture of the photographic lens is started. At #210, the pulses of the aperture encoder 211 described above are cycled from 1 to 1, and when the pulse set by the exposure calculation is reached, at #2, the magnet FMg is de-energized and the aperture is fixed.

After this, release magnet RM g at #212
Wait for the predetermined time L1 to elapse after power is applied to #21
Proceed to step 3. In #213, in order to prevent the photographic lens from being driven during exposure, the power to the AF mode M2 is turned off to 0FFL, and then in #2]4, the sequence mode M is turned off.
Make it F. As already explained, the brake of the Z-Kensmoke M1 is applied after the second frame of continuous shooting until it is turned off at #214.

#215: Macunet 1 for holding shutter 1 curtain],
By turning off the power to CM, the first curtain of the focal plane shutter runs, waits for the shutter speed at #216, and then turns the magnets 1 to 2 for holding the second shutter curtain at #2]7. Turn off the power and run 2K of the focal plane shutter. This completes the exposure. In #218, the timer value is saved in the memory TIME1. #219
Then, in order to wait for the second curtain of the focal plane shutter to complete its travel, the process waits for a predetermined time tlB to elapse, and then shifts to the winding routine (#220).

In the winding routine shown in FIG. 9, first, the sequence motor M is energized in low speed mode at #22;
After waiting for a predetermined period of time until the rotational speed of the motor M reaches 22 in step #22, the high-speed motor M 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, is turned OFF in #224.

When the switch SW2 is turned OFF and the mechanical charge sequence is completed, the main mirror and sub-mirror are down, so TTL photometry becomes possible and photometry is started at #225. Before proceeding to the film charge sequence, as described above, the stop release magnet (AMg) for stopping the film is energized for a predetermined time t6 (#226).

Thereafter, the process waits for a predetermined time tlo (#227), and then moves to #228. This predetermined time too is set to 3Qmsec in this embodiment, and is a waiting time for stabilizing the submirror. In #228, it is determined whether or not continuous shooting mode is selected by the photographer. If continuous shooting mode is selected, in #229, the continuous shooting flag VLYF is set without indicating that continuous shooting is in progress. 1, the process proceeds to focus detection processing CDINTA after #105 in order to perform focus detection next time (#230). On the other hand, if the mode is not continuous shooting mode, the process waits at #231 until the switch SW6 is turned off, and then proceeds to focus detection processing CDINTA from #105 onwards.

The automatic focus adjustment operation during continuous shooting will be described using flowchart 1 in FIG. 10. From #230 in Figure 9 #
After proceeding to focus detection processing CDINTA after 105,
As explained with reference to FIG. 7, focus detection calculation and exposure calculation are performed, and the process branches to continuous shooting A and F (#301) at #115. First, at #302, exposure calculation and serial communication are performed based on the photometric value set to star 1 at #225 in FIG.

This makes it possible to always obtain appropriate exposure even if the subject brightness changes during continuous 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 give priority to the next release since it is a continuous shooting mode.

When the OFF state of the switch SWI is detected, the film charging sequence has ended, so the sequence motor M1 is immediately braked at #304. 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 #306 that the film winding is slow, the following mote flag TF and the following initial flag Tl5TF are reset to 1 to 1 in #307, respectively. The following mode flag 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 continuous shooting interval is long and an error occurs in the correction for the subject movement, so the tracking mode flag TF is reset.

In #308, it is determined whether the focus detection result is low contrast. If the contrast is not low, 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 continuous 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. The previous focus detection result is saved in the memory LDF by the process #112 in FIG. Also, the lens position at the center of integration of the CCD that obtained the defocused DFO is:
Through the process #110 in FIG. 7, the lens position at the center of integration of the CCD at which the previous defocus LDF was calculated is saved in the memory MIL. As a result, the defocus change δDF caused by the movement of the subject is as follows: δDF=DFO-LDF-(MI-MIL>/KL...
・It is calculated as ■. DFO-LDF is the change in defocus, and (M I - M I L)/K L is the defocus due to the movement of the lens during that time. On the other hand, the time Δt 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, proceed to #34.1 19. On the other hand, if it is determined in #308 that the contrast is low, the process advances to #311. #311
Now, determine whether the previous ignore flag LIF is 1 or 0,
If it is cleared to O, the process advances to #312, where the previous ignore flag LIF is set, the current detection defocus DFO is set to 0, and the drive pulse number ERRCNT is set to 0. If the previous ignore flag LIF was set to 1 in #311, the release routine 0UTR■2 in #314
After branching to #315, the tracking mode flag TF and the tracking initial flag Tl5TF, which will be explained later, are reset, and the continuous shooting flag VLYF being cleared in #317, the process goes to #121, 0UTFS in FIG. and jump (#
318). As described above, when low contrast is detected twice in a row during focus detection during continuous shooting by the processing from #308 to #318, the continuous shooting mode is canceled, the release operation is prohibited, and the process shown in FIG. According to the flowchart explained in , release is prohibited until focus is achieved.

As a result, in the case of a moving subject, even if the subject moves out of the focus frame during continuous shooting, or if a subject with no contrast enters the picture, it is possible to take a picture at least once, so you will not miss a so-called dramatic moment. The probability is greatly reduced. Furthermore, the probability of significant defocusing is low. In particular, in continuous shooting mode, the photographer often wants to give priority to release, and this is particularly effective. Moreover,
If low contrast is detected twice in a row,
Since continuous shooting is interrupted until the camera is in focus again, the release will not continue with a large amount of defocus, and if the photographer is careless and takes continuous shots of an unintended subject, or if the photographer puts his or her hand in front of the shooting lens. Even in cases where the film is covered with dirt, the film is not wasted. #312 has low contrast this time, so defocus DFO5
The drive response number ERRCNT is undefined. Therefore, each of these is set to O. Furthermore, since the defocus speed VHO cannot be calculated, it is not updated.

That is, the previously detected defocus speed VHO is used. Subsequently, in #319, it is determined whether the mote is currently a following mote. If the tracking mode 1-flag TF has been reset and the tracking mode is not activated, the process advances to #320 and the defocus speed V obtained in #31B is
Compare HO and constant VEI, and if VHO>VEI, set constant F Z to INFZ, which is the focusing range, in #321.
RE I-1, #32 if V HO≦■E1
2, set the constants F Z RE L 2, respectively. FZREL1 is set narrower than FZR and EL2. In other words, when the defocus speed V HO is small, the subject is stationary, and in this case the defocus change due to subject movement is small, so a wide focusing range is set and the defocus speed V I (O is If it is large, the defocus change will be large, so set a narrow focusing range.This will reduce the need to drive the shooting lens when the subject is stationary, resulting in stable and fast continuous shooting. When shooting is possible and the defocus speed is larger than the defocus speed (VHO or predetermined speed VE), a narrow focusing range is used to achieve high-precision continuous shooting with little tracking delay.In addition, these constants VE], FZRELl, F
ZREL2 is written in the E2PROM 201f in the CPU 20 and can be rewritten according to the photographer's preferences. In #323, the focusing range INFZ set in #321 and #322 and the currently detected defocus DF
Compare with O. Defocus DFO is in focus range I N
If it is smaller than FZ, it is determined that the accuracy is sufficiently high, and #
The process advances to step 370, where it is determined whether the switch SW6 is ON. If the switch SW6 is ON, the photographer has requested the next release, and the process jumps to the next release (#371). In other words, since the accuracy is ensured, the next release is performed without performing mirror-up driving. If switch SW6 is OFF, #37
2 and subsequent release processing branches to 0UTRV, #373, #3
After resetting the continuous shooting flag VLYF, tracking initial flag T] and STF at step 74, focus detection processing from #1o5 onward is performed in order to perform the next focus detection.
Jump to A (#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 to drive the photographic lens or follow the 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. β> B E T A L O
In the case of CK, the process branches to #333. β≦BETA
In the case of LOCK, the process proceeds to #327, and it is determined whether the defocusing speed VHO is greater than the constants R and VMIN. If VHO≦R and VM I N, the process branches to #333, and if VHO>RVMIN, the process branches to #328. In #328, the defocus speed VHO is compared with the constant RVMAX.

If VHO≧R, VMAX, the process branches to #333, and if VHO<RVMAX, the process branches to #329. #
In step 329, it is determined whether the current and previous defocusing speeds VHO and VHI found in steps #310 and #313 are in the same direction or in opposite directions, and if they are in the opposite direction, the process branches to #336. #330 if in the same direction
Proceed to. #330 determines whether the follow-up first flag T] is set to STF or 1, and if it is cleared to O, branches to #335, sets it to 1, and flags that have already been set to 1. If it is set, the tracking mode flag TF is set to 1 in step #331, and the process jumps to the tracking processing routine R, NA, FTI.

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. In other words, if it is determined in #324 that the subject is dark, the CCD integration takes time and the noise component is large, so the defocus speed V HO cannot be determined accurately and the tracking mode cannot be entered. . Also,#
If it is determined in step 326 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. If the defocus speed VHO is less than the constant RVMIN in #327, it is not possible to determine whether the defocus change is caused by variations in focus detection or by the movement of the subject. does not enter. 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≧RVMAX,
The change in defocus is abnormally large and cannot be considered to be a movement of the subject; it is determined that the subject has changed, that is, the camera has been shaken, and the tracking mode cannot be entered. 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 of incorrect correction, and the tracking mode I can't enter it. Furthermore, #330, #33L#335
By performing the process described above, the tracking mode is entered when the determination conditions from #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 BETALO
CK, RVMIN, and RVMAX are written in the E2PROM 201f built in the CPU 201. #
If the direction of the defocus speed VHO is reversed at step 329, particularly unstable focus detection or subject movement is expected, so proceed to the cancellation process 0UTRV3 after #336, and set the tracking mode flag TF at #337. , reset the following initial flag Tl5TF and continuous shooting flag VLYF,
In order to perform the next focus detection, the process jumps to focus detection processing CDINTA after #105 (#338). As a result, the next release is prohibited, and as explained in FIG. 7, the lens is driven until the lens is brought into focus again, so there is no need to worry about out-of-focus photography being performed.

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 INFZEl. When DFO<INFZEI, the defocus is not very large and the reliability of focus detection is high, and sufficient accuracy is ensured even if the taking lens is driven by this amount of defocus while the mirror is up and the next release is performed. Therefore, the process branches to the drive routine RNMTR during mirror up. D
In the case of FO≧INFZE1, the defocus is large and if the next release is performed as it is, there is a possibility that accuracy cannot be ensured, so the release process 0UTRV2 hejump is performed (#334). By performing the processing in #333 and #334, when the defocus is small, high-precision automatic focusing and high-speed continuous shooting can be achieved by driving the mirror up, and when the defocus is large, it is possible to perform a transformation inspection. Highly accurate automatic focusing is achieved because the lens is brought out and focused.

Also, if the defocusing process ○UTFS is entered after the cancellation process 0UTRV2 from #334, as explained in Figure 7, the lens is driven by the amount of defocus DFO obtained during continuous shooting this time, and then the lens is restarted. Because it performs focus detection, it is fast and accurate. Also, the constant INFZE1 is the E2PR of the CPU 201.
It is written in the OM201r and can be changed according to the user's preference.

Now, the follow-up process RNAFTI executed by branching based on the determination in #319 or jumping from #332 will be explained with reference to FIG. First, in #340,
It is determined whether the directions of the current and previous defocusing speeds VHO and VHI are the same. If the directions are different, it is possible that the subject suddenly stopped, changed direction, or shook the camera. In this case, #3
41, jumps to cancellation processing 0UTRV3, cancels the tracking mode, and performs automatic focusing operation until focus is achieved 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 (VH
Compare O+VH1)/2 with the constant AVESH. (VI
-(0+VH1)/2 indicates n ], V old i''02 2 from the process of #310, and is a weighted average value. In the above formula, 11 is the number of loops, and V I-1i is 1 time. Does not show previous speed.

That is, in #342, the weighted average value and the constant AVES H
Compare with. The weighted average value is a constant A VE S I-
If it is less than 1, use #343 to change the defocus speed■HO
If the weighted average value is larger than the constant A VE S H, the process directly proceeds to #344. In other words, in the case of low speeds, by performing weighted averaging, stable correction is achieved that absorbs variations in focus detection, etc., and in the case of subjects approaching at constant speed, the change in defocus is approximately equal to the distance. Since it increases in inverse proportion to the square of the square, this realizes correction with good responsiveness and little follow-up delay at high speeds. In addition, the constant A VE S H is CPU2
It is written in E2PROM20If built in 01.

#344 Calculate the image magnification β and set the constant BETAL O
Compare with CK 2. As the image magnification increases, the influence of camera shake increases as described above, so in #347, cancel processing is performed.
It also comes out. Note that the constant B E T A L OCK2 is written in the E2PROM 2014 of the CPU 201, and is set larger than the constant B E T A L OCK. In #345, the defocus speed V HO is compared with the constant RVOUT, and if the defocus speed is within V HO months (VOUT), the defocus speed is sufficiently slow to avoid incorrect correction due to variations in focus detection, etc. , branches to #347. In #346, the defocus speed VITO is compared with the constant RVMAX2. If the defocus speed is VH○ or RVMAX2 or more, the defocus speed is very fast. It was determined that even if tracking correction was performed, the delay would be large and defocus would result.
Branches to #347. #347 Release process 0UTRV
Jump to 2, cancel tracking mode, prohibit release next time, and perform focus detection again. As a result, in the case of a very high-speed subject, the release is prohibited, and it is possible to prevent the camera from taking a picture of a subject that is too slow to follow. The processes of #344 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 0UTRV2 after #316 (FIG. 10) in order to improve accuracy. As a result, only the continuous shooting flag V L Y F is cleared, the tracking mode is maintained, and the out-of-focus processing is set to 0. UTF
Jump to S. Constant INFZE2 is CPU201
E2PROM 20], f. Also,
This constant INFZE2 is the constant I explained in #333.
It is set larger than NFZE1. This is because tracking correction is performed, and unless the correction amount is large, the process cannot proceed to #351.

#35] and subsequent steps 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 the switch SW6 is OFF, the next release is not requested, so the process branches to #363 and the release process O.
Jump to UTR,V. Subsequently, in #353, the number of driving pulses ERR, CNT and the constant NP]- are compared. As explained in FIG. 7, the constant NP1- is the number of pulses that can be driven during mirror up. Drive pulse number E
If RRCNT is equal to or less than the constant NPI, driving is possible during mirror up, and the process branches to #359.

If the number of driving pulses ERRCNT exceeds the constant NPI, driving cannot be performed only during mirror up, and therefore a driving time is required before the next release starts. Also, this A
The time required to drive the F motor M2 varies depending on power supply conditions, characteristics of the interchangeable lens, etc. For this reason, if the time until the next release start is fixed at 40 m5ec, and the number of drive pulses ERRCNT is 40 m5ec and the number of pulses that can be driven during the next mirror up (within constant NP2>), A
Drive the F motor M2 and increase the number of drive pulses ERRCNT.
If the value exceeds the constant NP2, refocus detection is performed. As a result, tracking correction can be performed accurately for 40m5ec even in the moving object mode. Also, even if you wait 4Q+n5ec, the continuous shooting speed will only drop from 3 frames per second to 2.7 frames per second, and the deterioration of the continuous shooting feel will be minimal. Furthermore, 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 40m5ee is performed in #355, if TF=0, skip #355, and in both cases, in #356, drive pulse number ERRCN
Compare T with constant NP2. Drive pulse number ERRCNT
If exceeds the constant NP2, the process branches to #364 and jumps to release processing 0UTRV2. #349, #35
If the next release is to be performed by driving during mirror up without detecting the focus again in the determination in step 6, it is determined that the camera is in focus, and the focus display is maintained. Subsequently, in #357, driving of the AF Momo-M2 is started, and in #358, the process waits for a time of 4Qmsec. At #359, the drive of the AF momo-M2 is started in case it branches from #353, and the process proceeds to continuous shooting release processing RNRELESE from #360 onwards. #3
61 is continuous shooting, so in order to completely stop the film, the camera waits for a predetermined time t11, and then jumps to the next release. As is clear from the above explanation, in the tracking mode, it is necessary to correct for changes in defocus caused by 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 was low contrast. 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, and by subtracting the value in the memory TM from the current timer value TC and adding the mirror up time of 70m5ec, the time from the current integration center to the next exposure can be calculated. Time is needed. In the case of low contrast, the process proceeds to #404 to find the time T from the previous exposure time to the next exposure time.

As explained in Figure 8, the previous exposure time is stored in the memory T.
It is saved in IME1. Therefore, subtract the value of memory T I ME 1 from the current timer value TC and get 7.
Just add 0 m5ec. That is, #402~
In #404, if the contrast is not low, the calculation is performed based on the current defocus DFO, and if the contrast is low, the calculation is performed assuming that the defocus was O during the previous exposure.

Next, in #405, the defocus speed VHO is set to the above #
Multiply by the time T obtained in step 403 or #404 to obtain the correction amount ΔD
I'm looking for F. Next, in #406, the defocus speed VHO and the constant VVH are compared. If VHO>VVH and the defocus speed is fast, it is determined in #407 whether the subject is approaching or going away, and if the subject is approaching, the correction amount ΔDF is multiplied by 1.25 (#408).

As mentioned above, if the subject approaches in the optical axis direction at a constant speed, the defocusing speed will increase in inverse proportion to the square of the subject distance.
The defocusing speed also increases during the time T determined in step 3 or #404. In order to correct this error, the correction amount ΔDF is multiplied by 1.25. When the subject is far away, the defocus speed becomes slower, so the correction amount Δ
Multiply DF by 0.75 (#409). Next, #410
This time detected defocus DFO and defocus speed VH
Check the direction of O, and if the direction is the same, the corrected defocus MDF will be DFO + ΔDF (#411)
. If the direction is different, the currently detected defocus DFO is compared with the correction amount ΔDF in #412, and DFO≦ΔDF is determined.
If so, set ΔDF-DFO in the corrected defocus MDF (#413). If DFO>ΔDF, the photographic lens must be driven in the direction opposite to the defocus speed direction, which means that a large defocus is detected in the direction opposite to the defocus speed direction. For this reason, in anticipation of errors caused by the reversal of the photographic lens or abnormal movement of the subject, stack initialization is performed in #414, and release processing ○UTR is performed in #415.
V2], the next release is prohibited and refocus detection is performed. Once the corrected defocus MDF is determined in #411-1 #413, the defocus is adjusted in #416.
Multiply by the coefficient K I- to convert to the number of pulses, set the number of drive pulses ERRCNT, and return (#4.1.7
>.

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

Finally, timer interrupts and ARP interrupts will be explained.

FIG. 13 shows a timer interrupt processing routine for driving the A and F motors M2. The CPU 201 has a built-in interrupt timer (not shown) that generates a timer interrupt when a set time has elapsed. When a timer interrupt occurs,
In #502, the interrupt timer IT is reset. As a result, after the current timer interrupt occurs, the interrupt timer IT
When the set time elapses, a timer interrupt is automatically generated.

Subsequently, the flag RMGONF is determined in #503, and if it is set, the release magnet RMg is being energized, so the AF momo-M2 is turned off as described above (#505). If the flags R and MGONF have been reset, the A and F motors M2 are energized in #504 and the process returns (#506).

FIG. 14 shows an AFP interrupt processing routine that occurs at the falling edge of the AFP signal. When an ARP interrupt occurs, first, in #602, the number of drive pulses ERR, CNT is decreased by one. In #603, the number of driving pulses ERRCNT becomes 0, and it is determined whether or not the driving of the A and F motors M2 has ended. Drive pulse number ERRCNT is not 0, A,
If the drive of F motor M2 is not finished, #6
The program proceeds to step 04, and the interrupt timer IT is reset from step 1. #
At 605, the flag RMGONF is checked. If the flag RMGONF is set to 1 or higher and the release magnet I-RMg is energized, A is set at #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,
If it is determined in #603 that the driving of AF Momo-M2 has been completed, the process branches to #609, and in #609, the driving of AF Momo-M2 is completed.
Turn off the power of 2. Subsequently, timer interrupts and AFP interrupts are inhibited using steps #610 and #61, respectively, and the process returns (#607). As mentioned above, timer interrupt and A
AF momo-M2 is driven by the FP interrupt, and AF momo-M2 is turned off while power is being supplied to Macnet RM g for release.
Controlled by FF.

[Effects of the Invention] In the automatic focusing camera of the present invention, the release is prohibited for a predetermined period of time from the end of the previous release during continuous shooting, and the lens is driven while the release is prohibited. This has the effect of ensuring accurate focusing, and since the lens drive time is limited to a predetermined time, the lens drive does not continue indefinitely, and the continuous shooting speed can be improved. This has the effect of preventing a large decrease in

Note that when the present invention is applied to a reflex camera that drives the lens while the mirror is up, the necessary lens drive can be performed by driving the lens while the release is prohibited and driving the lens while the mirror is up. This has the effect that the time can be shortened and the continuous shooting speed can be improved accordingly.

Further, by controlling the focus detection operation to be performed while the film is being wound up, the continuous shooting speed can be further improved.

Furthermore, if the subject is determined to be a moving object, the amount of lens drive can be corrected to offset the change in defocus amount due to the movement of the subject, which will improve the focusing accuracy when continuously shooting moving subjects. can be improved.

[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. FIGS. 5 and 6 are operation waveform diagrams similar to the above, and FIGS. 7 to 14 are flowcharts 1 showing the same operation. (1) is a focus detection means, (2) is a lens drive means, (3
) is a release control means, (4) is a timer means, (5)
(6) is a focus detection control means, (7) is a moving object determination means, and (8) is a tracking correction means.

Claims (4)

[Claims] (1) In an autofocus camera that has a continuous shooting mode in which the release operation continues continuously during the release operation, a focus detection means that detects the amount of defocus of the photographing lens with respect to the subject to be focused, and a detection output of the focus detection means a lens driving means for driving a focus adjustment lens toward a focusing position based on the above, a release control means for continuously performing a release operation, and a timer means for timing a predetermined time;
and a lens drive control means for inhibiting the next release by the release control means and driving the lens by the lens drive means until a predetermined time has been counted since the end of the previous release by the timer means. Jiao camera. (2) The automatic focusing camera according to claim 1, wherein the camera is a reflex camera, and the release control means is means for driving the lens by the lens driving means during mirror-up. 3. The automatic focusing camera according to claim 1, further comprising: (3) focus detection control means for operating the focus detection means during film winding. (4) A moving object determining means for determining whether or not the subject is a moving object based on the detection output of the focus detecting means; 4. The automatic focusing camera according to claim 3, further comprising tracking correction means for correcting the amount of lens driving by the lens driving means so as to offset the amount of change.