JPH02118539A - Automatic focusing camera - Google Patents

Abstract

PURPOSE:To secure focusing accuracy even if a subject moves during consecutive photography by providing a tracing correcting means, moving a lens by a lens moving means at the end of the photography, and correcting a focus detection result. CONSTITUTION:The focus state of a photographic lens as to the subject to be focused is detected by a focusing detecting means 1 and then its defocusing quantity is outputted. Then the tracing correcting means 2 finds the quantity of variation in defocusing quantity due to the movement of the subject. In this case, the focus detection result in film winding operation of last photography is used and the detecting means 1 performs focus detecting operation for tracking correction of next photography. Then the detecting means 1 performs detecting operation every time last photographing operation ends and the lens driving means 3 moves a lens for focus adjustment according to the quantity of variation in the defocusing quantity corrected by the correcting means 2 to put the lens in focus. Consequently, the focusing accuracy is secured even if the subject moves during the consecutive photography.

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, in the 1980s,
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 speed of the subject when the subject is moving.

On the other hand, during the release operation, the release operation is performed continuously,
Autofocus cameras are commercially available that have a snap-shot mode that can take multiple frames per second.

In addition, in autofocus cameras equipped with such a continuous shooting mode, focus detection is always performed even during rapid shooting, and the focus detection results are It has been proposed to use a continuous AF mode in which the lens is continuously driven toward the in-focus position based on the following.

[Problems to be Solved by the Invention] In an autofocus camera equipped with the above-mentioned quick-shooting mode, if tracking correction for a dynamic subject is performed during autofocus adjustment operation during continuous shooting, it is possible to improve the focus on a dynamic subject that is shot continuously. It is thought that accuracy can be improved.

However, in order to perform tracking correction, it is necessary to perform focus detection, and as the number of focus detection increases, there is a problem in that the speed of snapshots decreases.

The present invention has been made in view of these points, and an object of the present invention is to provide an automatic focusing camera that can perform tracking correction for a dynamic subject without reducing the speed of quick shooting.

[Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, in an autofocus camera that has a quick-shooting mode in which the release operation continues continuously during the release operation, a focus detection means detects the amount of defocus (defocus DFO) of the photographing lens with respect to the subject to be focused. (1) and the amount of change ΔD in the amount of defocus due to the movement of the subject
Tracking correction means (2) corrects the focus detection result by the focus detection means (1) by calculating F, and focuses the lens for focus adjustment according to the focus detection result MDF corrected by the tracking correction means (2). Lens driving means (3
), and the tracking correction means (2) is characterized in that it is a means for correcting the focus detection result during film winding during the previous shooting in continuous shooting mode.

Note that it is preferable that the follow-up correction means (2) is a means that performs correction at the end of the previous photographing operation.

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 tracking correction means (2) correspond to #401 to #417 in FIG. 12, and the lens driving means (3) correspond to #359 in FIG. 11, 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 tracking correction means (2) calculates the amount of change ΔDF in the amount of defocus due to the movement of the subject and corrects the defocus DFO. As this defocus DFO, the focus detection result during film winding during the previous shooting in the quick shooting mode is used. In other words, in the present invention, the focus detection operation is performed in parallel with the film winding operation during the previous shooting in continuous shooting mode, so the focus detection operation for tracking correction during the next shooting can be performed without reducing the continuous shooting speed. Can be done. In addition,
Since the film winding time varies depending on the degree of battery consumption, it is desirable to perform follow-up correction after film winding is completed, that is, at the end of the previous photographing operation. This results in
Accurate follow-up correction that is not affected by film winding time becomes possible. The lens drive means (3) includes a focus detection means (
Based on the defocus MDF detected by step 1) and corrected by tracking correction means (2), a focus adjustment lens is driven toward the in-focus position.

[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 101 is a camera body and 102 is a zoom lens which is an example of an interchangeable lens (photographing 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.
Leads to 4. The sub mirror 104 is the main mirror 103
The light that has passed through 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 camera body, 103 is a main mirror, 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 AFi1111ti 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 CCD drive section, an A/D conversion section, a reference power generation source for A/D conversion, etc. Image information obtained by this CCD is taken into the CPU 201 via the AF data bus 201a. 203 is a display unit consisting of a liquid crystal display (LCD) or a light emitting diode (LED), and an automatic exposure (hereinafter referred to as AE) sent from the CPU 201.
This display unit 203 displays information such as the shutter speed Tv and aperture value Av, which are the calculation results of (abbreviated as), in-focus/out-of-focus, and photographing mode. A lens data circuit 204 is provided inside each interchangeable lens 102 and stores the maximum aperture value, minimum aperture value, focal length, extension amount conversion coefficient necessary for focus adjustment, etc., and is used to connect the interchangeable lens 102 to the camera body. When attached to 101,
The data is transmitted to the camera body 101 via electrical contacts provided near the mounting section. 205 is a photometry unit that measures the brightness By of the subject, and includes a photoelectric conversion element for light reception;
A/D conversion section, reference voltage source for A/D conversion, CPU201
It is composed of a data exchange unit and the like, and measures the light that has passed through the photographic lens according to instructions from the CPU 201. 20
Reference numeral 6 denotes a film sensitivity reading section that 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. 207 is a sequence motor M1. for winding and rewinding the film. This is a driver control unit for exciting the AF MOMO-M2 that drives the lens for AF and various magnets required during exposure operation, and is controlled by the control output lines CMDO to CMD8 from the output terminals P8 to P16 of the CPU 201. . 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 FF when mechanical charging is completed. SW3 is a switch that repeats 0N10FF multiple times while the film is running. It is. 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, and 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 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 S
When W7 changes from OFF to ON, it indicates that the film is slightly out of the cartridge, and is used as a switch for determining the end of rewinding. SWS
is a cartridge detection switch installed near the electrical contact of the film sensitivity reading section 206 installed 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, the status will be OFF. SW9 is a back cover opening/closing switch, which is turned ON when the back cover is completely closed. 5WIO is a multiple exposure mode selection switch, and O
When set to N, the mode becomes multiple exposure mode.

RESET is connected to the 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 "Loin" level to the "High" level, the CPU 201 is reset. It has become. X is a crystal oscillator for providing a tarok signal to the CPU 201.

Next, the driver control section 207 and each control section will be explained. ICMg is a magnet for holding the first shutter curtain. When the control output line ICMGO goes to "Low" level, the magnet ICMH is energized and the first shutter curtain is held. 2CMg is a magnet for holding the second shutter curtain. It is a magnet, and the control output line 2CMGO is “Lou”.
i” level, the magnet 2CMg is energized, the second shutter curtain is held, and the time from when the first curtain shutter is released to when the second curtain shutter is released corresponds to the shutter speed. .FMg is a magnet for locking the aperture of the photographic lens, and the control output line FM
When GO reaches the ``Lou+'' level, the magnet FMH is energized to hold the aperture locking member, and when the holding is released, the aperture locking member operates and locks the aperture in a predetermined position. do. RMg is a magnet for the release,
When the control output line RMGO is at the "Low" level for a certain period of time, the release member is unlocked, the aperture is narrowed down, and the mirror is raised.

Q1~QIO is Z-Kensmoke M1 and AF Momo-M
This is the second driving transistor. This sequence motor M 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 can rotate in forward and reverse directions. Transistors Q1 to Q6 are connected as shown in FIG.

That is, the high-speed terminal H of the sequence motor M1 is connected to the common connection point of transistors Q1 and Q2, the low-speed side terminal is connected to the common connection point of transistors Q3 and Q4, and the remaining common terminal C is connected to the common connection point of transistors Q5 and Q6. are connected to each. Table 1 shows how the rotational state of the sequence motor M1 changes depending on the on/off states of the transistors Q1 to Q6.

(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 description, the term "brake" refers to the low-speed brake SBR. Q7 to QIO are transistors for driving the AF momo-M2, and are connected in a bridge configuration so that the AF momo-M2 can rotate in forward and reverse directions. AF Momo-M2 extends the lens by rotating it forward, and retracts it by rotating it in the reverse direction. OMI~
0M10 is a control output line for switching each transistor Q1 to QIO.

211 and 212 are an aperture encoder and an AF encoder made of photocouplers, and input signal lines PT1. P.T.
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 at the time of release, light emission from the light emitting diode 211a is detected by the phototransistor 211b and 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 passed to the input terminal P1 of the CPU 201 via the output signal line FP.
Sent on 8th. The AF 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.
2b, and is input to the driver control unit 207 via the input signal line PT2. After being waveform-shaped into a pulse by this driver control unit 207, it is passed through the output signal line AFP to the input terminal P19 of the CPU 201.
will be sent to. This output signal line AFP is also connected to a counter 20]d inside the CPU 201, and is used to monitor the extended position of the photographic lens. That is, the counter 201d is cleared to 0 at the lens end, and by setting it to count up when driving in the near direction and count down when driving in the ω direction, the number of pulses delivered from the ω end of the lens can be obtained at any time. Can be done.

This AFP signal is connected to an interrupt terminal (not shown) of the CPU 201.
It is also connected to 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 is a so-called E2PRO that can be written and read electrically and retains memory contents even when the power is turned off.
M201. It has a built-in f. Further, the CPU 201 includes an interrupt timer (not shown) that generates a timer interrupt when a set time has elapsed.

Table 2 Table 3 In the table, H is “High” level. In the table, H is °″High” level means “Low”° level.

L means 'Low' level.

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 used to control the magnets RMg and FM, respectively, and the control output line R for control.
Control MGO, FMGO, CMD2. CMD3 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 motor M2 by CMD8
Controls 0. Table 2 shows the control of the sequence motor M, and Table 3 shows the control of the AF motor M2. In the table, H is “
"High" level, and L means "Low level."

AMg is a lock release magnet that holds the film still, and transistors Q11. CPU2 via resistor R2
01 output terminal P17. Transistor Q1
The connection point between the base of 1 and the resistor R2 is grounded via the resistor R3. The output terminal P17 of CPU2O1 is normally “Lo”.
u+'' level and the transistor Qll is off, so the magnet AMg is not energized and holds the attraction piece by attraction. In order to release the engagement between the winding stopper and the winding stopper lever, the CPU 201 Output terminal P17 is '
When the magnet AMH reaches the "High" level, the magnet AMH 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 charge sequence, the film is advanced.

This will be explained in more detail below using a time chart. As already explained in FIG. 4, the switch SW6 is turned on by pressing down the shutter button two steps to start the release operation. When the release operation starts, first, the control output line RMGO is set to the "Loa+N level," thereby energizing the release magnet RMg and releasing the main mirror biased by the spring. , the main mirror is retracted to the finder side, and the sub-mirror is also retracted in conjunction with the main mirror.Subsequently, by setting the control output line FMGO to the "Low" level, the aperture locking magnet FMH
energizes and releases the diaphragm of the photographic lens, which is biased by a spring. When the lock is released, the aperture starts, and as explained in FIG. The signal is doubled and input to the CPU 201 . CPU20
1 counts the number of FP multiplied signals corresponding to the aperture value based on a predetermined exposure calculation, and sets the control output line FMGO to "'High".
By setting the aperture level to the desired aperture value, the aperture is stopped and the photographing lens is set to the desired aperture value. Next, in order to perform the exposure operation, one of the control output lines 10MG0, 2CMGO, which is at the ``Low'' level at the start of the release, is set to the ``High'' level. runs.

After the exposure time based on a predetermined exposure calculation has elapsed, the other control output line 2CMGO is set to the "High" level, thereby causing the two curtains of the focal plane shutter to run and exposure control to be performed. After exposure, a mechanical charge sequence begins. In the mechanical charging sequence, first, high torque is required when starting the sequence motor M1, so the sequence motor M1 is driven in low speed mode F(L), and then, when the predetermined rotation speed is reached, high speed mode F(L) with low torque and high speed rotation is performed. H). As a result, the sequence motor M can be driven efficiently, and high-speed mechanical charging and film charging can be achieved.

The 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 photographing lens and the first and second curtains of the focal brain 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 film charging is turned on, and the sequence motor M winds up the film. When film winding for one frame is completed, switch SWI is turned to O.
It becomes FF, and the CPU 201 G, m is notified. C
When the PU 201 detects that the switch SWI is OFF, it applies a brake (not shown) to stop the sequence motor M. This completes the release operation for one frame.

Next, the sequence in the snapshot mode in which the camera is released continuously while the switch SW6 is ON will be described with reference to the time chart of 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 quick shooting. Section 1 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 sub-mirror are lowered and stabilized. Due to this, switch SW2 turns OFF,
After completing the mechanical charge and waiting for time for the mirror to stabilize, COD integration is started. In this example, this waiting time is set to 30m5ec. In the figure, the part indicated by ■ is the COD integration time, and the part 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 COD pixel data 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 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 camera is in the snapshot mode, then the release of the second frame, which is indicated by section 3, is started. 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 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, when taking pictures that are out of focus, especially when shooting in quick-shot mode, there are many cases where the subject is moving and the defocus of such subjects changes over time, so in calculation 1, detects the amount of defocus caused by the movement of the subject. 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 ``Low'' 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 started, it sends a start signal and a clock to the peripheral IC in #101, and performs start-up processing such as initializing the boat.Subsequently, in #102, flags, constants, etc. used in the program are initialized. conduct. continue,#
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.Furthermore, in order to discharge unnecessary charges from the COD, which is a focus detection element, initialization is performed in step #104.

Next, the process proceeds to focus detection processing CD I NTA (#105 onwards). 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 (7M2
-Save TMl>/2. TMI and 7M2 indicate the integration start and end times, respectively, (TM27MI)
/2 means the time of the center of integration. That is, #109
Then, 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 value of the memory MI is saved in the memory MIL in #110, and the value of the memory MI is saved in the memory Ml (T2-
Save Tl)/2. As mentioned above, since the counter value corresponds to the lens position, Tl and T2 indicate the lens position at the start and end of integration, respectively, and (T2 - Tl)
/2 indicates the lens position at the center of integration, i.e.
In #110, the lens position of the previous integration center is M
The lens position of the current integration center is saved in IL and MI, respectively.

Next, in #111, each pixel data of the CCD is sent to the CPU2.
Using this COD pixel data, which is inputted in step 01, the value of the memory DFO is saved in the memory LDF in step #112 before starting the focus detection calculation. At this point, focus detection by CCD integration in #107 has not been performed, so the process in #112 saves the previously detected defocus DFO in the memory LDF. In #113, #107
A focus detection calculation is performed based on the COD pixel data integrated in , and the defocus DFO and defocus direction of the photographing lens as well as the reliability of focus detection are calculated. continue,
At #114, serial communication and exposure calculation are performed, and photometric values are displayed and each switch is sensed. For example, if the 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 the serial communication and exposure calculation are completed, the process proceeds to #115, where it is determined based on the flag VLYF whether or not a snapshot is currently being taken. This continuous shooting flag VLYF is set to 1 when the photographer has selected the continuous shooting mode during the winding operation, which will be explained later. If the continuous shooting flag -LYF is 1 in the determination in #115, the flow branches to the quick shooting AF (#301). The flowchart of continuous shooting AF will be explained in detail later using FIG. 10.

If the continuous shooting flag VLYF is 0, the process proceeds to #116, where 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. In this case, the predetermined amount is 100
It is set to μm. Further, this value may be set to 60 μm+8X (247og2FNo+1.), taking into account the depth of focus rather than the aperture value of the photographic lens set by exposure calculation, where 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. After this is performed to reflect the focus detection result in the exposure calculation, the CPU waits while performing serial communication in #120 until the ON of switch SW6 is detected in #11.

If it is determined in #116 that the focus is not in focus, #121
Proceed to subsequent out-of-focus processing 0UTFS 6 First, #122
to turn off the focus display, and then in step #123, if the focus detection calculation result is determined to be unreliable and cannot be used, that is, it is determined to be low contrast, the next focus detection will be performed without driving the AF motor M2. In order to perform this, the process branches to focus detection processing CD INTA from #105 onwards. If the contrast is not low, proceed to #124 to start driving the AF motor M2, wait until the drive is finished in #125, and then proceed to focus detection processing CD INTA from #105 onwards in order to perform the next focus detection. In step #124, the defocus DFO is multiplied by the conversion coefficient KL obtained from the photographic lens, and the number of driving pulses ERT' (
Calculate CNT.

In other words, the number of driving pulses ERRCNT is ERR,CN
It is determined by T = DFOXKL. #12
5 is an AF for monitoring the rotation of AF motor M2.
A until the P signal is detected for the number of drive pulses ERRCNT.
F motor 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 number of driving pulses ERRCNT is smaller than the constant NPI written in the E"PROM 201r mentioned above (#126). If the number of lSK driving pulses ERRCNT is greater than or equal to the constant NP1, the driving pulse Reset the constant NPI to the number ERRCNT (#127), and set the drive pulse number ERR.
If CNT is smaller than the constant NPI, just #
Proceed to 128. 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 proceeds 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). At #129, the number of drive pulses ERRCNT is 4
If it is equal to or greater than the pulse, driving of AF Momo-M 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 determination is performed based 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. In addition, when the subject is a moving object, the detected defocus changes from moment to moment, so focus cannot be determined. Therefore, this focusing range does not take into account variations in focus detection or changes in defocus due to changes in the subject. It is set to a size that can absorb the amount of water. However, in this case, the defocus corresponding to the focusing range remains as an error. For this reason, this remaining defocus is used during mirror up to create an even more accurate autofocus camera. 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, in #128 DFO<D
If it is FCI, or if the drive pulse number ERRCNT is smaller than 4 in #129, AF Momo-M2
The drive accuracy of the camera is also taken into consideration, and the shutter is released immediately.

Next, a series of release controls (#201 onwards) including mirror up, exposure time control, mechanical charging, and film winding will be explained using FIG. first,#
At #202, the flag RMGONF indicating that the release magnet (RMg) is energized is set to 1, and #20
Step 3 energizes the AF MOMO-M2 to 0FFL, and step #204 energizes the release magnet RMg, shutter curtain holding magnet) ICMg, and 2CMg. after that,#
After waiting for a time in step 205, the energization to the release magnet RMg is set to 0FFt in step #206, and the flag RMGONF is cleared to O in step #207. #2 from this #204
By the process of 06, the main mirror sub-mirror is unlocked and mirror-up is started. Also, #202, #2
03 and #207, the energization of the AF momo-M2 is prohibited while the magnet RMg is energized. Specifically, AF Momo-M2 is controlled by turning on AF Momo-M2 by a timer interrupt that occurs at predetermined time intervals.
This is done by braking by interrupting the P signal, and when the flag RMGONF is 1, turning on AF Momo-M2 and braking are both prohibited, and AF Momo-M
2 is set to 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 when AF Momo-M2 is energized, 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 any inconvenience.

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. In #210, the pulses of the aperture encoder 211 described above are counted, and when the pulses set by the exposure calculation are calculated, the magnet FMH is de-energized in #211 to fix the aperture. After this, in #212, wait for a predetermined time t to elapse from energizing the release magnet RM, and proceed to #213. In #213, the photographing lens is prevented from being driven during exposure. In order to do this, turn on the power to AF Momo-M2
FL, then turn off sequence motor M1 with #214
Make it. As already explained, the sequence motor M,
In the case of the second and subsequent frames of quick shooting, the brake is applied until it is turned off in #214.

#215: Magnetic IC for holding the cover and 1st curtain
By turning off the power to Mg, the first curtain of the focal plane shutter runs, waits for the shutter speed in #216, and turns off the power to the magnet 2CMH for holding the second shutter curtain in #217. ,
Four power! Run the second curtain of the Leplane shutter.

This completes the exposure. In #218, the timer value is saved in the memory TIME1. In #219, in order to wait for the second curtain of the focal plane shutter to complete its travel, the process waits for a predetermined time t's to elapse, and then proceeds to the winding routine (#220>).

In the winding routine shown in FIG. 9, first, in #221, sequence motor M1 is energized in low speed mode, and in #2
After waiting for a predetermined time until the rotational speed of the motor M1 increases in step 22, high-speed mode energization is performed in step #223. As a result, mechanical charging progresses, and switch SW2, which is a mechanical charging completion signal, is activated in step #224. Wait until it turns OFF.

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. In order to proceed 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 t1° (#227), and then moves to #228. This predetermined time t1° is set to 30 m5ec in this embodiment, and is a waiting time for stabilizing the submirror. In #228, it is determined whether the photographer has selected the quick shooting mode, and if it is the continuous shooting mode, the continuous shooting flag VLYF, which indicates that continuous shooting is in progress, is set to 1 in #229. After setting,
In order to perform focus detection next time, the process advances to focus detection processing CD-NTA after #105 (#230). On the other hand, when not in the snapshot mode, until switch SW6 is turned OFF,
After waiting at #231, focus detection processing C after #105
Proceed to D 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. First, 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 quick 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 this is a quick 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 mode flag TF and the following initial flag Tl5TF are respectively reset in #307. The tracking mode flag TF will be explained later, but when the subject is a moving object, it is set during the tracking mode in which moving bones of the subject are corrected. 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 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 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. The previous focus detection result is saved in the memory LDF by the process #112 in FIG. Also, the lens position at the fine center 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: δDF=DFO-LDF-(MI-MI L>/KL・
...■ is calculated. 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 (2) and (2), the subject speed VHO is determined as VHO=δDF/Δt.

After determining the subject velocity VHO in #313, the process proceeds to #319. On the other hand, if it is determined in #308 that the contrast is low, the process proceeds to #311.In #311, it is determined whether the previous ignore flag LIF is 1 or 0, and if it is cleared to O, the process proceeds to #311. , proceeds to #312, sets the previous ignore flag LIF, and sets O1 drive pulse number ERRCNT in the current detection defocus DFO. #31
1, if the previous ignore flag LIF is set to 1, the process branches to the cancellation routine 0UTRV2 in #314, and in #315, the following mode flag TF and the following initial flag Tl5TF, which will be explained later, are reset, respectively. #
After clearing the continuous shooting flag VLYF at 317, jump to 0UTFS at #121 in Figure 7 (#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 quick shooting mode is canceled, the release operation is prohibited, and the process shown in Fig. 7 is performed again. According to the flowchart described above, 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 can avoid missing so-called measurable moments. The probability is greatly reduced. Furthermore, the probability of significant defocusing is low. In particular, in the snapshot mode, the photographer often wants to give priority to the release, and this is particularly effective. Moreover,
If low contrast is detected twice in a row,
Since snapshots are interrupted until the camera is in focus again, the release will not be continued with a large amount of defocus, and this may occur if the photographer is careless and takes a quick snapshot of an unintended subject, or if the front of the photographic lens is covered with a hand. There is no need to waste film even in such cases. #312 has low contrast this time, so defocus DFO5
The number of drive pulses ERRCNT is undefined. Therefore, each of these is set to 0. 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 current tracking mode is selected. If the tracking mode flag TF has been reset and it is not the tracking mode, the process advances to #320 and the defocus speed VHO determined in #313 is
and the constant ■E1, and if VH, O>VEI, the constant FZR is added to the focusing range INFZ in #321.
In the case of VHO≦VE1, the constant FZREL2 is set in #322. FZRELL is F
It is set narrower than ZREL2. In other words, when the defocus speed VHO 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 when the defocus speed VHO is large, the subject is stationary. , since the defocus change is large, set a narrow focusing range. As a result, when the subject is stationary, the photographing lens is not driven much, and stable and fast shooting is possible.When the defocus speed VHO is greater than the predetermined speed VE1, By using a narrow focusing range, we achieved high-precision snapshots with little tracking lag. Also, these constants V
EI, FZRELI, and FZREL2 are written in the E2PROM 201f in the CPU 201, and can be rewritten according to the photographer's preference. In #323, #32
1. The focusing range INFZ set in #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, the process proceeds to #370, and the switch SW6 is
It is determined whether or not is ON. If the switch SW6 is ON, the photographer has requested the next release, and the process jumps to the next release (#371). That is,
Since accuracy is ensured, the next release is possible without having to drive while the mirror is up. Switch SW6 is O
If it is FF, the process branches to release processing 0UTRV after #372, and the continuous shooting flag VLYF is set in #373 and #374.
After resetting the initial tracking flag Tl5TF, in order to perform the next focus detection, focus detection processing CD from #105 onwards.
Jump to INTA (#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>BETALOCK, #33
Branches into 3. If β≦BETA LOCK, the process proceeds to #327, and it is determined whether the defocus speed V HO is greater than the constants R and V MIN. VHO
If ≦RVMIN, branch to #333 and VHO
>If RVMI N, proceed to #328, #328
Now, the defocus speed V)10 will be compared with the constant RVMAX.

If V T-10≧RVMAX, the process branches to #333, and if VHO<RVMAX, the process branches to #329.

In #329, it is determined whether the current and previous defocusing speeds VHO and VHI obtained in #31o and #313 are in the same direction or in opposite directions, and if they are in opposite directions, the process branches to #336. , #33 if in the same direction
In #330, it is determined whether the follow-up initial flag Tl5TF is set to 1, and if it is cleared to 0, it branches to #335 and is set to 1.
If it has already been set to 1, the tracking mode flag 1゛F is set to 1 in #331, and the tracking processing routine R
Jump to NAFTI.

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, it takes time to integrate the COD 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. In #327, the defocus speed ■1-(If 0 is less than the constant RVMIN, it is not possible to determine whether the defocus change is caused by variations in focus detection or by the movement of the subject, and in order to avoid erroneous correction. , the tracking mode cannot be entered.Even if the defocus changes due to the movement of the subject, the speed is slow, so the defocus changes are 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 incorrect correction.Also, the constant BETA
LOCK, RVMIN, and RVMAX are E2PROM201. It is written in f. If the direction of the defocus speed VHO is reversed in #32, particularly unstable focus detection or subject movement is expected, so cancel processing 0UTRV after #336
3, reset the tracking mode flag TF, initial tracking flag Tl5TF, and continuous shooting flag VLYF in #337, and jump to focus detection processing CI) INTA from #105 onwards in order to perform the next focus detection (# 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 < I NFZE 1, the defocus is not very large and the reliability of focus detection is high, ensuring sufficient accuracy even if the taking lens is driven by this defocus amount during mirror up and the next release is performed. Therefore, the process branches to the drive routine RNMTR during mirror up. In the case of DFO≧INFZE1, the defocus is large and if you release the camera next time as it is, there is a possibility that accuracy cannot be ensured. Therefore, perform the cancellation process 0UTRV2 hejump (#334), #333, and #334. When the defocus is small, highly accurate automatic focusing and high-speed continuous shooting can be achieved by driving the mirror up while the defocus is large, and when the defocus is large, the transformation point is detected and focused. Automatic focusing is achieved.

In addition, if the defocusing process 0UTFS is entered after the cancellation process 0UTRV2 from #334, as explained in FIG. The detection is fast and accurate. Also, the constant INFZE1 is the E2PR of the CPU 201.
It is written in the OM201f and can be changed according to the user's preference.

Now, the follow-up process r (NAFTr) executed by the branch based on the determination in #319 or the jump from #332 will be explained with reference to FIG. Determine whether they are the same or not. If the directions are different, it may be because the subject suddenly stopped, changed direction, or shook the camera. In this case, #
The process branches to step 341, jumps to cancellation processing 0UTRV3, cancels the tracking mode, and performs automatic focusing operation until focus is achieved again. This causes the subject to suddenly stop,
Even if you change direction or shake the camera, you can achieve high-precision focusing without making erroneous corrections.

If they are in the same direction, proceed to #342 and (VH
Compare O+VH1)/2 with the constant AVESH. (VH
From the process #310, O+VH1)/2 indicates n I VHi and becomes a weighted average value. In the above formula, n is the number of loops, and V Hi indicates the previous speed.

That is, in #342, the weighted average value and the constant AVESH are compared. If the weighted average value is less than the constant AVESH, the weighted average value is re-applied to the defocusing speed VHO in #343, and if it is greater than the constant AVESH, the process directly proceeds to #344. In other words, in the case of low speed By performing weighted averaging, stable correction is achieved that absorbs variations in focus detection, etc. In the case of a subject approaching at a constant speed, the change in defocus increases in inverse proportion to the square of the distance. As a result, at high speeds, it is possible to achieve correction with good responsiveness and little follow-up delay. In addition, the constant AVESH is the E2PROM2 built in the CPU201.
It is written in 01f.

In #344, calculate the image magnification β and use the constant BETALOC
Compare with K2. As the image magnification increases, the influence of camera shake increases as described above, so the canceling process 0UTRV2 is yanked at #347 and the tracking mode is also exited. In addition, the constant BBTALOCK2 is the E'PR of the CPU 201.
It is written in OM201r and the constant BETALOC
It is set larger than K. #345 compares the defocus speed VHO and the constant RVOUT, and if the defocus speed VHO is within RVOUT, the defocus speed is sufficiently slow, and # Branch to 347. #346
Now, the defocus speed VHO and the constant RVMAX2 will be compared. If the defocusing speed VHO is equal to or higher than RVMAX2, it is determined that the defocusing speed is very fast and that even if follow-up correction is performed, the delay will be large and defocusing will occur, and the process branches to #347. In #347, the cancellation process is 0UT.
Jump to RV2, 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. #344~#346
This process prevents erroneous corrections and achieves highly accurate corrections.

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 #349, 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 ○tJTRV21 after #316 (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 E2PROM of CPU201
201f. Also, this constant INFZ
E2 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 the switch SW6 is OFF, the next release is not requested, so the process branches to #363 and the release process 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 driving pulses ERRCNT is less than or equal to 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. Therefore, if the time until the next release start is fixed at 40 m5ec, and the number of driving pulses ERRCNT is within 40 m5ec and the number of pulses that can be driven during the next mirror up (constant NP2), the AF
The motor M2 is driven, and if the number of drive pulses ERRCNT exceeds the constant NP2, refocusing is performed. As a result, tracking correction can be performed accurately for 40 m5ec even in the moving object mode. Also, even if you wait for 4Q+n5ee, the rapid shooting speed of 3 frames per second will only drop to 2.7 frames per second, and the deterioration of continuous shooting will be minimal. Furthermore, when the number of driving pulses ERRCNT exceeds the constant NP2, refocusing is performed, so that the problem that errors associated with lens driving increase indefinitely remains unsolved.

If BRR, CNT≦NP1 in #353, #354
Then, the tracking flag TF is determined. If #354 is tracking mode (TF = 1), tracking correction calculation 2 for 40m5ec is performed in #355, if TF = 0, #355 is skipped, and in both cases, drive pulse number ERRC is determined in #356.
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
Disconnect the drive of motor M2 and drive 40m5ec with #358.
Wait for an amount of time. In #359, the drive of AF motor M2 is started in case it branches from #353, and in #36
Proceed to the quick-shooting release process RNRELESE after 0.
Since #361 is a quick shot, in order to completely stop the film, it waits for a predetermined time tl+ and then jumps to the next release.As is clear from the explanation of 0 or more, in tracking mode, the defocus change due to the subject is Since this must be corrected, the shooting lens remains stopped and the next release is not performed.

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, when the contrast is not low, the calculation is performed based on the current defocus DFO, and when the contrast is low, the calculation is performed assuming that the defocus was 0 during the previous exposure.

Next, in #405, the defocus speed V HO is multiplied by the time T obtained in #403 or #404 above to obtain the correction amount Δ.
6. Determining DF 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 is approaching in the optical axis direction at a constant speed, the defocusing speed is 2 times the subject distance.
It increases in inverse proportion to the power of the power, so as the speed increases, #4 above
The defocus speed also increases during the time T determined in step 03 or #404. In order to correct this error, the correction amount ΔDF is multiplied by 1.25. When the subject is moving away, the defocus speed becomes slow, so the correction amount ΔDF is multiplied by 0.75 (#409), and then #41
0, this time detected defocus DFO and defocus speed V
Check the direction of HO, 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 and the correction amount ΔDF are compared in #412, and DFO≦ΔD.
If F, ΔDF-DFO is applied to the corrected defocus MDF.
(#41 B), if DFO >ΔDF', the photographic lens must be driven in the opposite direction to the defocus speed direction, causing a large defocus in the opposite direction to the defocus speed direction. This means that it has been detected. Therefore, assuming a backlash error due to the reversal of the photographic lens or abnormal movement of the subject, stack initialization is performed in #414, and release processing 0UTRV is performed in #415.
By proceeding to step 21, the next release is prohibited and refocusing detection is performed. #411, #413 correct defocus M
When DF is determined, in #416, it is multiplied by a coefficient KL that converts defocus into the number of pulses, and the number of driving pulses ERRCN is determined.
Set T and return (#417).

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

Finally, timer interrupts and ARP interrupts will be explained.

FIG. 13 shows a timer interrupt processing routine for driving AF Momo-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, #5
At step 02, the interrupt timer IT is reset. As a result, the interrupt timer IT automatically generates a timer interrupt when the set time has elapsed after the current timer interrupt occurs.

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 flag RMGONF has been reset, AF Momo-M2 is energized in #504,
Return (#506).

FIG. 14 shows an AFP interrupt processing routine that occurs at the falling edge of the AFP signal. When an AFP interrupt occurs, first, in #602, the number of drive pulses ERRCNT is decreased by one. In #603, the number of drive pulses ERRCNT becomes O, and it is determined whether or not the drive of the AF momo-M2 has ended. The number of driving pulses ERRCNT is not 0, and the AF momo-M
If the drive in step 2 is not completed, proceed to #604,
Reset the interrupt timer IT. At #605, the flag RMGONF is checked. Flag RMGONF
is set and the release magnet RMg is energized, turn AF MOMO-M2 off with #608.
Make it F. 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, in the judgment of #603, AF
If the driving of Momo-M2 has been completed, the process branches to #609, and in #609, the power supply to AF Momo-M2 is turned off.

Next, timer interrupts are made at #610 and #611, respectively.
Disable AFP interrupts and return (#607). As described above, the AF momo-M2 is driven by the timer interrupt and the AFP 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, tracking correction is performed on the focus detection result during film winding during the previous shooting in continuous shooting mode, so it is possible to reduce the continuous shooting speed. This has the effect that the focus detection operation for follow-up correction at the time of the next photographing can be performed.

Note that if the follow-up correction is performed at the end of the previous photographing operation, accurate follow-up correction can be performed without being affected by the film winding time.

[Brief explanation of drawings]

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 focus detection means, (2) is tracking correction means, (3)
is a lens driving means.

Claims (2)

[Claims] (1) In an autofocus camera that has a continuous shooting mode that continues the release operation during the release operation, there is a focus detection means that detects the amount of defocus of the photographic lens with respect to the subject to be focused on, and a focus detection means that detects the amount of defocus of the photographing lens with respect to the subject to be focused, and a focus detection means that detects the amount of defocus of the photographic lens with respect to the subject to be focused on. Tracking correction means for correcting the focus detection result by the focus detection means by determining the amount of change in the amount of deviation, and driving the focus adjustment lens toward the in-focus position in accordance with the focus detection result corrected by the tracking correction means. 1. An automatic focusing camera comprising: a lens drive means, wherein the follow-up correction means is means for correcting a focus detection result during film winding during previous shooting in continuous shooting mode. (2) The automatic focusing camera according to claim 1, wherein the follow-up correction means is a means for performing correction at the end of the previous photographing operation.