JPH0644092B2 - Camera with automatic focus adjustment - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a single-lens reflex camera equipped with an TTL focus detection type automatic focus adjustment device.

(Background of the Invention) Conventionally, some cameras of this type include an automatic film winding mechanism and a TTL focus detection type charge storage type automatic focus adjusting device for continuous shooting. In the case of shooting, in order to place importance on the shooting interval time, the shooting lens is stopped at the position controlled by the automatic focus adjustment device at the time of shooting the first frame, and thereafter, until the continuous shooting is completed, It has been proposed that the photographing lens is configured so that photographing is performed while the photographing lens is fixed at the stop position. With this kind of camera,
In the case of continuous shooting, if the release operation is performed without focusing on the first shooting, there is a possibility that all the photographs will be out of focus until the continuous shooting ends. In order to solve this problem, it is conceivable to perform automatic focus adjustment control (AF control) for each shooting even during continuous shooting. However, with this configuration, the processing time for accurately performing the AF control must be considered, and the above-described shooting interval time must be lengthened.

(Object of the Invention) The present invention solves this drawback, and always provides a good focusing state of the taking lens even during continuous shooting, and is provided with an automatic focusing device that does not extend the interval time too much. The purpose is to provide a camera.

(Summary of the Invention) The present invention has a technical point that the servo of the photographing lens after the exposure of the photographing is continuously restarted in the continuous photographing of the camera based on the residual servo amount obtained after the photographing. There is.

(Embodiment) FIG. 1 shows an arithmetic circuit of a camera capable of automatic focusing according to an embodiment of the present invention.

In FIG. 1, the arithmetic processing circuit of the camera is composed of a microcomputer (hereinafter, referred to as a microcomputer) 1, in which automatic exposure (AE) calculation and automatic focusing (AF) are performed.
Detection calculation processing and the like are performed. This microcomputer 1 is usually A
Two processes, the E calculation process and the AF calculation process, are performed in parallel.

The AF calculation process will be described first. The microcomputer 1 determines from the signal from the lens system detection circuit 6 whether or not the taking lens L is a lens capable of automatic focusing. If the lens is capable of automatic focusing, the reflected light from the subject is stored in a charge-accumulating photoelectric sensor. The conversion element (CCD) 2 receives the light, outputs the output signal to the AD converter 3, converts it into digital data, and stores it in the RAM which is a memory means of the microcomputer 1. The microcomputer 1 uses this R
The defocus amount (servo amount) up to the in-focus position of the photographing lens is detected and stored by processing the subject signal stored in the AM by an appropriate algorithm, for example, an algorithm of a known shift detection method. The AF control circuit 5 built in the camera based on the stored defocus amount
Controls the taking lens L to the in-focus position. The focus state of the taking lens is displayed by the display circuit 4 in the viewfinder of the camera.

Next, the AE calculation process will be described. The microcomputer 1 has
The ISO sensitivity signal from the ISO setting unit 7 of the camera, the open F value signal from the open F value generation unit 8 of the taking lens, and the subject brightness signal from the photometric circuit 9 are input to the microcomputer 1, and
One of the automatic exposure control mode (shutter time priority, aperture priority, and program automatic exposure control) and manual exposure control mode is selected from the shooting mode setting unit 10, and the shutter time setting unit 11 and the aperture value setting unit are selected accordingly. A signal is input from 12 and the microcomputer 1 performs an exposure calculation process. The result of this exposure calculation is displayed by the display circuit 4, and by inputting the release signal of the release circuit 13 associated with the release button, the exposure control circuit 14 incorporated in the camera operates to take an image.

The display circuit 4 is configured to drive a display element such as an LED or a liquid crystal. Further, the camera is provided with an automatic winding circuit 16 (for example, a film winding device built in the camera or an external motor drive device), and the automatic winding circuit 16 has a continuous automatic winding or a single automatic winding. A signal from the S / C switching circuit 17 for selecting the upper side is input.

Next, the flow charts of the examples are shown in Attached Tables 1 to 3. The normal photographing sequence of the camera will be described based on the attached table 1, and attached tables 2 and 3 are the AE routine and the A of the attached table 1.
The flowchart of F routine is shown.

The normal shooting sequence operation of the camera will be described with reference to Attachment 1. In step S21, the power is turned on by pressing the release button of the camera halfway, and all the circuits of the camera start operating. In step S22, it is determined whether or not the photographic lens mounted on the camera is a photographic lens capable of automatic focusing. At this time, if the AF lens signal is not input into the microcomputer 1 from the lens system detection circuit 6, the camera is not equipped with an AF lens and the process proceeds to step S23. In step S23, the operation of the AF control circuit 5 is prohibited, and the process proceeds to step S24. At this time, the AF calculation process is continuously operated so that only the focused state of the taking lens L is displayed on the display circuit 4. Is also good. Step S24
At the same time, AF calculation processing is performed and the calculation result is displayed in the viewfinder of the camera by the display circuit 4. In step S25, the release button of the camera is fully pressed, and in step S26, the exposure control circuit 14 is activated to perform exposure control (a series of operations based on the shutter release, i.e., aperture narrowing, mirror up, shutter release). The automatic exposure control) is performed to control the exposure of the film so that the exposure is appropriate. When the filming of one frame is completed, the film is automatically wound by a film winding motor built in the camera or an external motor drive, and the camera is set to the shooting start state again.

When it is determined in step S22 that the taking lens attached to the camera is the AF lens, in step S28, the AE routine and the AF routine shown in the separate tables 2 and 3 are jumped to control them in parallel. To do.

Next, the AF routine will be described with reference to Attachment 3. In step S41, the CCD 2 is reset by discharging residual charge, and in step S42, the interrupt timer starts timing, and the AE interrupt routine (Appendix Table 2) of the AE calculation process operates in parallel with the AF routine to keep constant. AE every cycle
The calculation process (step S31) is performed, and the result is displayed momentarily in the finder (step S32).
In step S43, the CCD 2 receives the reflected light from the subject and starts charge accumulation, and when a certain amount of charge is accumulated, the charge accumulation ends in step S44. In step S45, the interrupt of the AE interrupt routine is temporarily prohibited,
The electric charges accumulated in the CCD 2 are input to the microcomputer 1 via the AD conversion circuit 3 (in step S47) as digital data, and AF calculation processing is performed. C in step S48
The CD2 is reset, the AE interrupt routine is activated again in step S49, and the interrupt timer is activated in step S50. Along with the AE display, the result of the AF calculation processing by the microcomputer 1 in step S51 is stored as a servo amount in the memory means in the microcomputer 1 and AF-displayed on the display circuit 4, and the photographing lens L is AF-based on the servo amount. It is driven to the in-focus position by the control circuit 5.

In step S52, it is determined whether or not the AF lock circuit 15 (installed on the camera side or the photographing release side) is activated and the photographing lens L is locked. If the AF is locked, the process proceeds to step S53 to release the shutter. It is determined whether or not the button is fully pressed, and if it is fully pressed, it is determined in step S62 whether or not the continuous shooting mode is set. If it is the single shooting mode, the process proceeds to step S61, in which the exposure control circuit 14 operates in response to the exposure control, that is, the release operation (the pressing operation of the release button of the camera) to perform the film exposure operation, and the process returns to the beginning of the AF routine. If the S / C switching circuit 17 provided on the camera side is set to the continuous shooting mode, the automatic hoisting circuit 16 operates to enable continuous shooting, and in step S63, the high-speed continuous shooting mode ( That is, the shooting interval is approximately the total time of the exposure control time and the film winding time), and the exposure control is performed and the exposure control circuit responds to the release operation (the pressing operation of the release button of the camera). 14 is activated and the film is exposed, and if continuous shooting is completed, A
Return to the beginning of the F routine.

If the AF lock is not performed in step S52, it is determined in step S54 whether or not the release button has been fully pressed. If it is not fully pressed, the process returns to the beginning of the AF routine and the AF calculation process is periodically performed.

Steps S54 to S58 will be described with reference to FIG. If the release button is fully pressed in step S54, the stop circuit 19 for prohibiting the operation of the AF control circuit 5 in the microcomputer 1 is output from the release circuit 13, and the stop signal is output from the microcomputer 1 in step S55. The operation of the AF control circuit 5 is prohibited by the signal, and the driving of the photographing lens is forcibly stopped even during the AF servo until the exposure of the film is completed. In step S56, it is determined whether or not the continuous shooting mode is set. If the S / C switching circuit 17 provided on the camera side is set to the continuous shooting mode, the automatic winding circuit 16 operates to enable continuous shooting, and the process proceeds from step S56 to step S57.

In step S57, the exposure control is performed in response to the release operation to expose the film, but if the release operation at this time is not completely performed when the taking lens is in focus, the servo amount during the release operation is set. And the amount by which the photographic lens is actually driven are subtracted to obtain the remaining servo amount, and the photographic lens is driven at the time of film winding immediately after the film exposure is completed based on this residual servo amount. Specifically, the photographic lens drive amount detection circuit 18 detects a photographic lens drive amount signal from the rotation amount of the photographic lens drive motor, for example, and outputs it to the comparison means 21 in the microcomputer 1, and also the first memory The means 20 outputs the signal of the servo amount during the release operation stored therein to the comparison means 21. Then, the comparison means 21 subtracts the servo amount and the drive amount to calculate the remaining servo amount, and the second memory means 22.
To memorize. The residual servo amount signal stored in the second memory means 22 is output to the AF control circuit 5. The comparing means 21 is configured to operate when the S / C switching circuit 17 is in the continuous shooting mode, and inhibit the operation when the single shooting mode is in effect. If the S / C switching circuit 17 is in the single shooting mode, the first memory means does not output the stored servo amount to the comparing means 21, but directly outputs it to the AF control circuit 5. ing. In step S58, when the exposure control is performed even when the taking lens L is not focused at the time of the previous exposure control, the residual AF servo until the next new servo amount is calculated is determined by the microcomputer. Based on the residual servo amount stored in the second memory means in 1, the film exposure is completed, that is, the next film winding is started, and the residual AF is performed.
The CCD 2 is reset with the servo and charge accumulation starts immediately after the residual AF servo, and the exposure control and AF control are performed again based on the new servo amount through the same process as described above (step S41 to step S51) in step S59. It is made to be seen. The interval time of each shooting at the time of continuous shooting is determined to be as short as possible in consideration of the charge storage time of the CCD due to the subject brightness, and the AF control system of the camera is configured as described above. Even if the subject is not in focus during the release operation during continuous shooting, it can be compensated by the residual AF servo, and the subject can be focused immediately.

If it is determined in step S56 that the mode is single shooting mode instead of continuous shooting, exposure control is performed in step S61 to perform film exposure, the next film is wound up, and the process returns to the beginning of the AF routine.

Generally, in a camera that performs AF control for each frame during continuous shooting, the film is wound up (several 100 ms) after the exposure is completed, and then charge accumulation in the CCD for AF control (for example, the brightness of the subject) is performed. It varies depending on the practical use, but in practice, it is from several 100 ms to 1 s) and AD conversion (from several ms to several 10).
ms) and AF algorithm execution (from several tens of ms)
(About 100 ms) and the like, and the total time of these steps is the interval time for continuous shooting, but according to the flowchart shown in Appendix 3 of the embodiment, it is stored at the beginning of the release operation during continuous shooting. The residual AF servo is performed when the exposure of the film is completed based on the residual servo amount obtained based on the servo amount.
Driving is not performed during servo, the interval time for continuous shooting can be shortened, and AF servo is continuously performed after exposure control is completed, so that quick focusing is performed even during continuous shooting. In addition, when shooting with a moving subject during continuous shooting, it is quite possible to release even if the subject is not perfectly focused, and the movement of the subject usually has directionality. If the AF servo is performed based on the servo amount stored at the beginning of the release operation as described above, it is possible to perform the AF servo with good followability.

Furthermore, when the AF lock is performed and the continuous shooting mode is set, high-speed continuous shooting is possible.

(Effect of the Invention) According to the present invention as described above, the servo of the photographing lens after the exposure of the photographing is restarted in the continuous photographing of the camera based on the residual servo amount obtained at the photographing, so that the residual servo amount Is not driven during the next AF servo, the interval time of continuous shooting can be shortened, and the automatic focus servo from the end of each shooting exposure to the start of the next exposure can be performed smoothly and continuously, which is stable. This makes it possible for the photographer to take a sensational servo and to take a picture easily and with good operability.

Incidentally, according to the embodiment, in the past, it was often the case that the continuous shooting was out of focus, but in the embodiment, the shooting interval time (C when the operability and the subject have low brightness)
Since the residual AF servo is performed based on the servo amount stored at the beginning of the release operation as described above, the interval exposure time determined in consideration of the charge storage time of CD2 is set to a fixed time, and thus the film exposure is completed. It can be effectively used during the film winding time afterwards, and the shooting lens can be brought into focus faster by the residual AF servo.
Focusing is possible even during continuous shooting. Furthermore, focusing can be performed by following the movement of the subject, and AF
There is an advantage that the followability of the servo becomes smooth.

[Brief description of drawings]

FIG. 1 shows a block diagram of a camera according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the functions of the microcomputer. (Explanation of symbols of main parts) 1 ... Microcomputer, L ... Photographing lens

Claims (1)

[Claims] 1. A focus detecting means using a charge storage type photoelectric conversion element, which drives the taking lens based on the servo amount of the taking lens obtained by the focus detecting means and drives the release operation of the camera. In a camera capable of continuous shooting, which is equipped with an automatic focus adjusting device for stopping the shooting, and an automatic winding device for automatically winding a film, the servo amount of the shooting lens obtained by the focus detecting means during continuous shooting is stored. And a servo amount stored in the memory means, and an exposure operation is completed based on a residual servo amount obtained by subtracting a drive amount driven by the photographing lens until just before the exposure operation of the film is started based on the servo amount. A camera equipped with an automatic focusing device, characterized in that the camera is equipped with a servo means for driving a photographing lens immediately after.