JP2006220928A - Automatic focusing camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a shutter chance from being missed by scanning operation. <P>SOLUTION: The scanning operation is inhibited for a predetermined time tpTH after turning off an AF switch 62. If the predetermined time tpTH elapses when the AF switch 62 is operated to be turned on, the scanning operation is started. Therefore, when a release button is operated to be turned on/off frequently so as to repeat the turning on/off of the AF switch 62, nonconformity that the scanning operation is started even if a low-contrast subject is prevented, and the possibility of deciding focusing gets high. As a result, anxiety that the shutter chance is missed is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automatic focus adjustment camera that performs focus detection by driving an AF lens when it is determined that focus detection is impossible.

Japanese Patent Laid-Open No. 11-281886 discloses an automatic focus adjustment camera that performs focus detection by scanning an AF lens when it is determined that focus detection is impossible.
Japanese Patent Laid-Open No. 11-281886

  In the automatic focus adjustment camera of Patent Document 1, when the AF switch (release switch) is turned on, if the focus cannot be detected, a timer is started and a scanning operation is started after a predetermined time. As a result, under a situation where the composition is changed to focus on a different subject from the target on the shooting screen and the AF switch is frequently turned on and off, the subject to be focused is low contrast, etc. Even if the focus cannot be detected, the scanning operation is prohibited every time the camera is turned on. As a result, the scanning operation is not started indefinitely, and there is a possibility of missing a photo opportunity.

(1) An automatic focus adjustment camera according to the first aspect of the present invention is a photoelectric conversion means for picking up an image of a subject through a taking lens and outputting focus detection image data; a command output means for outputting a focus adjustment instruction; When a focus adjustment command is output from the output means, based on focus detection image data output from the photoelectric conversion means, a focus detection means for detecting the focus adjustment state of the photographing lens, and based on a detection result of the focus detection means When a focus adjustment command is output and a focus adjustment command is output, if the determination unit determines that focus detection is impossible, the photoelectric conversion unit captures an image of the subject while scanning the photographing lens. Scanning operation control means, and a focus adjustment command is no longer output from the command output means. If it is determined to be out, and wherein, further comprising a lens driving means for driving toward the in-focus position taking lens on the basis of the detection result of the focus detection means.
(2) According to the invention of claim 2, in the automatic focus adjustment camera of claim 1, when it is determined by the determination means that focus detection is possible while the scanning operation is prohibited by the prohibition means, the focus detection means Based on the detection result, the photographic lens is driven toward the in-focus position by the lens driving means.
(3) According to the invention of claim 3, in the automatic focus adjustment camera of claim 1 or 2, while the scanning operation is prohibited by the prohibiting means, it is determined that the focus detection is impossible by the determining means, and a predetermined time has passed. If the determination means still determines that focus detection is still impossible, the scan operation control means scans the photographing lens and images the subject by the photoelectric conversion means.
(4) The invention of claim 4 is the automatic focusing camera according to any one of claims 1 to 3, wherein the prohibiting means is an elapsed time after the focus adjustment command is not output from the command output means. Time measuring means, and elapsed time determining means for determining whether or not the elapsed time measured by the measuring means at the time when the focus adjustment command is output after the focus adjustment command is not output is greater than or equal to a predetermined time. The prohibiting means permits the scanning operation of the photographic lens when the elapsed time is determined to be equal to or longer than the predetermined time by the elapsed time determining means, and when the elapsed time is not determined to be longer than the predetermined time as the elapsed time determining means, The scan operation is prohibited.

  According to the present invention, since the scanning operation is prohibited for a predetermined time from the time when the output of the focus adjustment command is stopped, the possibility that the unnecessary scanning operation continues and the photo opportunity is missed is reduced.

  Embodiments of the present invention will be described below with reference to the drawings. The single-lens reflex electronic still camera according to the present embodiment controls the prohibition / permission of the scan operation as the focus adjustment operation according to the operation state of the AF switch.

-First embodiment-
As shown in FIG. 1, a single-lens reflex electronic still camera according to this embodiment includes a camera body 10, a finder device 20 attached to and detached from the camera body 10, photographing lenses 31a to 31c, and a diaphragm 32. 10 and an interchangeable lens 30 that is attached to and detached from the camera. The lens group 31b is a focus adjustment lens (hereinafter referred to as an AF lens) and is driven by a lens drive motor (hereinafter referred to as an AF motor) 33. The subject light enters the camera body 10 through the interchangeable lens 30 and is guided to the finder device 20 by the quick return mirror 11 before being released to form an image on a finder mat (not shown). The subject image is guided from the pentaprism 21 through the relay lens 22 to the eyepiece lens 23 and is formed on the light receiving surface of the photometry element 24 from the pentaprism 21 by an optical element (not shown). Before the release, the subject light is reflected downward by the sub-mirror 12 of the quick return mirror 11 and then enters the focus detection device 40 via the mirror 13. On the other hand, after the release, the quick return mirror 11 rotates upward, and the subject light forms an image on the photographing imaging device 14 via a shutter (not shown).

  The focus detection device 40 is, for example, a well-known phase difference type focus detection device, and a focus detection optical system that divides a focus detection light beam into a pair of focus detection light images and a pair of divided light images are incident thereon. And a pair of CCD line sensors for outputting a focus detection signal. The focus detection signal output from the CCD line sensor is input to the control circuit 50, and the control circuit 50 drives the AF lens 31b to the in-focus position. The control circuit 50 includes a CPU, a ROM, a RAM, and various peripheral circuits. Functionally, the control circuit 50 calculates a CCD control unit 51 that controls the CCD line sensor and an image plane shift amount (defocus amount) with respect to the planned focal plane. A defocus amount calculation unit 52, a lens target position calculation unit 53 that calculates the target position of the AF lens 31b based on the image plane deviation amount, and a lens drive signal calculation that calculates an AF lens drive signal based on the AF lens target position Unit 54, a scan operation instruction unit 55 for outputting a scan operation command by the AF lens 31b to the lens drive signal calculation unit 54, a predetermined time for prohibiting the scan operation, and a scan prohibit signal until the predetermined time is counted. And a scan inhibition timer 56 for outputting a scan permission signal to the scan operation instruction section 55 after a predetermined time is counted. .

  The defocus amount calculation unit 52 determines whether focus detection is possible or not. For example, when the defocus amount based on the focus detection signal cannot be calculated due to low contrast of the subject or the reliability of the calculated defocus amount is low, it is determined that the focus cannot be detected, and the defocus amount is high. When the focus amount is calculated, it is determined that the focus can be detected. The defocus amount calculation unit 52 also performs in-focus determination based on the calculated defocus amount. For example, if the calculated defocus amount is within a predetermined allowable range, it is determined to be in focus, and if it is outside the allowable range, it is determined to be out of focus.

  The scan operation instruction unit 55 calculates the lens drive signal so that the AF lens 31b performs the scan operation when it is determined that the focus detection is impossible by the defocus amount calculation unit 52 and a predetermined condition described later is satisfied. A scan operation command signal is output to the unit 54. When the scan operation command signal is input, the lens drive signal calculation unit 54 calculates a lens drive signal for performing the scan operation of the AF lens 31b, and the AF motor 33 causes the AF lens 31b to perform a scan operation based on the lens drive signal. . During the scan operation, the focus detection signals sequentially output from the CCD of the focus detection device 40 are input to the defocus amount calculation unit 52, so that the defocus amount is repeatedly calculated during the scan operation.

  The control circuit 50 includes a power switch 61, a focus adjustment command switch (hereinafter referred to as an AF switch) 62 for instructing start of focus adjustment, a full-press switch 63, an AF-S / AF-C changeover switch 64, Is connected. The AF switch 62 is a release half-push switch or an AF-dedicated switch.

  When the power switch 61 is turned on, the control circuit 50 starts the focus adjustment calculation. That is, the focus detection calculation is performed based on the focus detection signal sent from the CCD line sensor at a predetermined cycle, and the lens target position for driving the AF lens 31b to the in-focus position is repeatedly calculated.

  When the AF switch 62 is turned on, a focus adjustment command is output, and the control circuit 50 sends the latest lens target position signal calculated by the lens drive signal calculation unit 54 to the AF motor 33 to move the AF lens 31b. Drive to the in-focus position.

  When the full-push switch 63 is turned on, the charge due to the subject image is accumulated in the photographing imaging device 14 for the exposure time calculated by the exposure, and image data based on the accumulated charge is recorded on the recording medium.

  The AF-S / AF-C selector switch 64 has a single mode in which shooting is not performed unless the focus is determined when the full-press switch 63 is turned on, and an in-focus determination is made when the full-press switch 63 is turned on. This is a switch for changing the shutter priority mode in which shooting is performed even if there is not. In this specification, the operation of the camera will be described on the assumption that the changeover switch 64 is switched to the AF-S mode.

The scanning operation in the present embodiment will be described with reference to FIGS.
In FIG. 2A, when the AF switch 62 is operated from OFF to ON at time t1, the lens target position calculation unit 53 sends the latest lens target position to the lens drive signal calculation unit 54, and the lens drive signal calculation unit. 54 generates a lens drive signal corresponding to the received lens target position and drives the AF motor 33. As a result, the AF lens 31b moves to the in-focus position. At this time, the scan prohibit timer 56 outputs a scan enable signal, and when the defocus amount calculation unit 52 determines that focus detection is impossible, the scan operation instruction unit 55 sends a scan operation command signal to the lens drive signal calculation unit 54. Output.

  When the AF switch 62 is turned off from ON at time t2, the scan prohibit timer 56 outputs a scan prohibit signal and starts measuring time. A predetermined time tpTH is set in the timer 56, and until the time tpTH is counted, the scan prohibit timer 56 outputs a scan prohibit command to the scan operation instruction unit 55, and the scan prohibit timer 56 outputs a predetermined time at time t4. When tpTH is timed, the scan prohibit timer 56 outputs a scan permission command to the scan operation instruction unit 55.

  When the AF switch 62 is turned on again from OFF at time t3, the lens target position calculation unit 53 sends the latest lens target position to the lens drive signal calculation unit 54, and the lens drive signal calculation unit 54 receives the received lens target. A lens drive signal corresponding to the position is generated to drive the AF motor 33. As a result, the AF lens 31b moves to the in-focus position. At this time, since the scan prohibition signal is output from the scan prohibition timer 56, even if the defocus amount calculation unit 52 determines that focus detection is impossible, the scan operation instruction unit 55 sends a scan operation command to the lens drive signal calculation unit 54. Do not instruct. Therefore, the AF lens 31b does not perform a scanning operation.

  When the scan prohibit timer 56 counts the predetermined time tpTH at time t4, the scan prohibit timer 56 outputs a scan permit signal to the scan operation instruction unit 55. Therefore, if the defocus amount calculation unit 52 determines that focus detection is impossible at time t4, the scan operation instruction unit 55 instructs the lens drive signal calculation unit 54 to perform a scan operation at time t4, and the lens drive signal calculation unit 54 Scan-drives the AF motor 33 to scan the AF lens 31b. Alternatively, if the defocus amount calculation unit 52 determines that focus detection is impossible after time t4, the AF motor 33 is scan-driven at that time and the AF lens 31b performs a scanning operation.

  As shown in FIG. 2 (b), when the AF switch 62 is operated from ON to OFF at time t5 after time t4, the scan prohibit timer 56 starts timing from time t5 and outputs a scan prohibit signal. Thereafter, the scanning operation is prohibited during the predetermined time tpTH.

  FIG. 3 shows a case where the AF switch 62 is operated from ON to OFF at time t31 before the scan prohibit timer 56 counts the predetermined time tpTH. In this case, the scan prohibit timer 56 is reset from time t31 and a new time measurement is started. That is, the scan inhibition timer 56 outputs a scan inhibition signal for a predetermined time tpTH calculated from the time point t31.

Processing as described above is performed by executing a focus adjustment processing program in the control circuit 50. FIG. 4 is a flowchart showing the focus adjustment processing program.
This program is started in step S101 when the power switch 61 is turned on, and a predetermined time tpTH is set in the scan inhibition timer 56 in step S102. In step S103, driving of the CCD line sensor of the focus detection device 40 is controlled, and a focus detection signal output from the CCD line sensor is read. In step S104, a defocus amount is calculated based on the read focus detection signal, and a lens target position is calculated and stored based on the calculated defocus amount.

  When it is determined in step S105 that the AF switch 62 is OFF, the process proceeds to step S106, where the driving of the AF motor 33 is stopped, that is, the focus adjustment operation by the AF lens 31b is stopped. Then, the process proceeds to step S107, and if it is determined that the AF switch 62 was ON when this process was executed last time, the process proceeds to step S108. The process proceeds from step S107 to step S108 when the AF switch 62 is operated from OFF to ON.

  In step S108, the scan prohibit timer 56 is reset. That is, zero is set to the time count tp. Thereafter, when it is determined in step S109 that the time tp of the scan inhibition timer 56 is less than the predetermined time tpTH, a predetermined time δt is added to the time tp of the scan inhibition timer 56 in step S110 to obtain a new time tp. Return to step S103. On the other hand, when it is determined in step S109 that the time tp of the scan inhibition timer 56 is equal to or greater than the predetermined time tpTH, the time measurement of the scan inhibition timer 56 is stopped in step S112 and the process returns to step S103. If a negative determination is made in step S107, the process proceeds to step S109. The process proceeds from step S107 to step S109 when the AF switch 62 is continuously turned OFF.

  If it is determined in step S105 that the AF switch 62 is ON, the process proceeds to step S20, and processing for driving the AF lens 31b is executed. The process proceeds from step S105 to step S20 immediately after the power switch 61 is turned on and the AF switch 62 is turned on from OFF, and when the ON operation is continued after the ON operation. After executing Step S20, the process proceeds to Step S109.

The AF lens driving process in step S20 will be described with reference to FIG.
In step S201, the AF lens driving process is started. In step S202, it is determined whether focus detection is possible or focus detection is not possible as described above. If it is determined in step S202 that focus detection is possible, the process proceeds to step S203. If it is determined in step S203 that the AF lens 31b is performing a scanning operation, the scanning operation is stopped in step S204, and the process proceeds to step S208. On the other hand, if it is determined in step S203 that the scanning operation is not being performed, the process directly proceeds to step S208. In step S208, the focus determination is performed as described above. If it is determined in step S208 that the subject is in focus, the AF lens 31b is driven to the target lens position in step S209. Thereafter, the shutter prohibition flag is turned on in step S220.

  If it is determined in step S202 that focus detection is impossible and the scan prohibit timer 56 is operating in step S205, that is, if it is determined that the time count tp is less than the predetermined time tpTH, scanning is performed in step S206 while focus detection is not possible. A command to prohibit operation is output. If the AF lens 31b is driven, the driving is stopped in step S210. Thereafter, the shutter prohibition flag is turned on in step S221.

  On the other hand, if it is determined in step S205 that the scan prohibit timer 56 is not operating, a command for permitting the scan operation is output in step S207. In step S211, the AF lens 31b is scanned. Thereafter, the shutter prohibition flag is turned on in step S222.

  FIG. 6 is a flowchart showing a shooting processing program executed by turning on the full push switch 63.

  When the full push switch 63 is turned on, the program of FIG. 6 is started in step S301, and in step S302, it is determined whether or not the shutter prohibition flag is on. If it is determined that the shutter prohibition flag is ON, no image is taken regardless of whether the full-press switch 63 is ON. On the other hand, if the shutter prohibition flag is off, step S302 is denied, the CCD (photoelectric conversion element) of the imaging device 14 is reset in step S303, and an image is taken in the calculated exposure condition in step S304. After the exposure time has elapsed, image data is read from the CCD in step S305, known image processing is performed in step S306, and the captured image data is recorded on a recording medium in step S307.

The operation of the single-lens reflex electronic still camera according to such an embodiment will be described.
When the power switch 61 is turned on, focus detection is started, and the calculation of the defocus amount and the lens target position is repeated. When the AF switch 62 is turned on for the first time after the power switch 61 is turned on, the AF lens 31b is driven to the in-focus position if focus detection is possible. When the AF switch 62 is turned on after being turned off, the scanning operation by the AF lens 31b is prohibited while the time count tp of the scan inhibition timer 56 is less than the predetermined time tpTH at that time. During this time, the AF motor 33 is driven by the lens target position, which is the latest calculation result, and the AF lens 31b moves to the in-focus position regardless of whether focus detection is possible or focus detection is not performed, and the focus adjustment operation is performed. When the AF switch 62 is continuously turned on, the scan operation is permitted when the scan prohibit timer 56 counts the time tpTH. Therefore, if the focus cannot be detected, the scanning operation is started, and then the shutter prohibition flag is set. Therefore, even if the full-press switch 63 is turned on, photographing is prohibited.

  If the shutter prohibition flag is off when the full-press switch 63 is operated, the quick return mirror 11 rotates upward, and the subject light from the interchangeable lens 30 forms an image on the light receiving surface of the imaging device 14 for photographing. In addition, signal charge corresponding to the brightness of the subject image is accumulated in the imaging device 14 for photographing. The signal charge accumulated in the imaging device 14 is recorded on a recording medium as a digital image signal. When the full-press switch 63 is operated, if the shutter prohibition flag is on, photographing is prohibited. That is, as described above, while the AF lens 31b is being driven, as in the case where the AF lens 31b is driven during the scanning operation or when the scanning operation is not performed but the defocus amount is not driven to the focus allowable range, Even if the switch 63 is turned on, photographing is prohibited.

  In the single-lens reflex electronic still camera according to the first embodiment described above, the elapsed time tp measured by the scan inhibition timer 56 when the focus adjustment command is output after the focus adjustment command is not output is equal to or longer than the predetermined time tpTH. A determination means for determining whether or not the elapsed time tp is determined to be equal to or greater than the predetermined time tpTH by the determination means, the scanning operation of the AF lens 31b is permitted, and the elapsed time tp is determined to be equal to or greater than the predetermined time tpTH. If not determined, the scanning operation of the AF lens 31b is prohibited. In such a single-lens reflex electronic still camera according to the first embodiment, focusing is performed in a situation where the composition is changed to focus on a different subject from the target on the shooting screen and the AF switch is turned on / off. When focus detection is impossible due to the low contrast of the subject being attempted, the scanning operation is started within a short time after the ON operation compared to the conventional example in which the scanning operation is prohibited starting from the ON operation. As a result, the scanning operation is not started endlessly, and the missed photo opportunity is reduced.

-Second Embodiment-
In the first embodiment, the scan prohibit timer 56 starts timing when the AF switch 62 is operated from ON to OFF, but in the second embodiment, when the AF switch 62 is operated from OFF to ON. The scanning prohibition timer 56 starts timing and controls the prohibition / permission of the scanning operation according to the elapsed time from when the AF switch 62 is turned off to when it is turned on again. Here, when the elapsed time is equal to or longer than the predetermined time, the scan operation prohibition time is set to zero and the scan operation is substantially prohibited without being prohibited. When the elapsed time is less than the predetermined time, the scan operation prohibition time is determined as the scan operation prohibition time. The scanning operation is prohibited by setting a predetermined time.

  For this reason, the electronic camera according to the second embodiment shown in FIG. The OFF timer 57 measures the elapsed time from when the AF switch 62 is turned off to when the AF switch 62 is turned on, and permits or prohibits the scanning operation based on the measured OFF time. For example, if the measured OFF time is less than the predetermined time tsTH, the scanning operation is prohibited so that the AF lens 31b does not perform the scanning operation. On the other hand, if the measured OFF time is equal to or longer than the predetermined time tsTH, the scanning operation is permitted, and when the predetermined condition is satisfied, the AF lens 31b performs the scanning operation.

The scan operation in the second embodiment will be described with reference to FIG.
In FIG. 8, when the AF switch 62 is turned on from time OFF at time t11, the lens target position calculation unit 53 sends the latest lens target position to the lens drive signal calculation unit 54, and the lens drive signal calculation unit 54 receives the lens target signal. The AF motor 33 is driven by generating a lens driving signal corresponding to the target lens position. As a result, the AF lens 31b moves to the in-focus position. At this time, it is assumed that a scan permission signal is output from the scan prohibit timer 56.

  When the AF switch 62 is operated from ON to OFF at time t12, the OFF timer 57 is activated to start measuring the AF switch OFF duration. When the AF switch 62 is turned on from time OFF at time t13, if the measured AF switch OFF duration is less than the predetermined time tsTH, the scanning operation is prohibited, and the measured AF switch OFF duration is the predetermined time. If it is equal to or greater than tsTH, the scanning operation is permitted.

  Processing as described above is performed by executing a focus adjustment processing program in the control circuit 50. FIG. 9 is a flowchart showing the focus adjustment processing program. In the flowchart of FIG. 9, steps similar to those in the flowchart of FIG. 4 are denoted by the same reference numerals, and differences will mainly be described.

  If it is determined in step S107 that the AF switch 62 was ON when this process was executed last time, the process proceeds to step S301, and the time ts counted by the AF switch OFF timer 57 is reset. On the other hand, if it is determined that the AF switch 62 was not previously turned on, the process proceeds to step S302, and a predetermined time δt is added to the time ts of the AF switch OFF timer 57 to obtain a new time ts. In step S303, the time tp counted by the scan inhibition timer 56 is reset to zero, and the process proceeds to step S304. In step S304, it is determined whether the time ts measured by the AF switch OFF timer 57 exceeds a predetermined time tsTH. If step S304 is negative, the process returns to step 103. If a positive determination is made in step S304, the process proceeds to step S102.

  If it is determined in step S105 that the AF switch 62 is not OFF, that is, is ON, the process proceeds to step S310. If it is determined in step S310 that the time tp of the scan inhibition timer 56 is less than the predetermined time tpTH, a new time measurement is performed by adding the predetermined time δt to the time tp timed by the scan inhibition timer 56 in step S311. Let time tp. On the other hand, if it is determined in step S310 that the time tp measured by the scan inhibition timer 56 is equal to or greater than the predetermined time tpTH, the time measurement by the scan inhibition timer 56 is stopped in step S312. In step S313, the process proceeds to the AF lens driving process shown in FIG.

  In the electronic camera according to the second embodiment described above, while it is determined that the time ts of the AF switch OFF timer 57 is less than the predetermined time tsTH, the time tp of the shutter prohibit timer 56 is determined in step 303. Since zero is still set and step S310 is affirmed, the process proceeds to step S311 and the scanning operation is prohibited. On the other hand, while it is determined that the time count ts of the AF switch OFF timer 57 is equal to or greater than the predetermined time tsTH, the predetermined time tpTH is set as the time count tp of the shutter prohibition timer 56 in step 102. If no, the process proceeds to step S312, and the scanning operation is permitted. In other words, when the AF switch 62 is turned on, the scanning operation is prohibited if the immediately preceding OFF duration is short, and the scanning operation is permitted if the OFF duration is long.

  That is, in the single-lens reflex electronic still camera according to the second embodiment, after the focus adjustment command is not output, the OFF duration time ts measured by the AF switch OFF timer 57 when the focus adjustment command is output is a predetermined time. including determination means for determining whether or not the time is tsTH or more, and when the determination means determines that the duration time ts is equal to or greater than the predetermined time tsTH, as a result, the scanning operation of the AF lens 31b is permitted, and the determination means determines the duration time ts. When it is not determined that the time is tsTH or more, the scanning operation of the AF lens 31b is prohibited as a result. Therefore, in the single-lens reflex electronic still camera according to the second embodiment, as in the single-lens reflex electronic still camera according to the first embodiment, when the AF switch 62 is operated from OFF to ON, compared to the conventional example. The scanning operation is started in a short time, and the possibility of missing a photo opportunity is reduced.

  Further, the long OFF time of the AF switch 62 is a case where the user consciously changes the composition. In this case, in the electronic still camera according to the second embodiment, the scanning operation is started immediately and the subject is moved. Even low contrast can be focused quickly. Conversely, the short OFF time of the AF switch 62 is a case where the user consciously changes the composition in order to follow a moving subject. In this case, the same subject can be obtained without performing a scanning operation. Since there is a high possibility of quick focusing, the electronic still camera according to the second embodiment can quickly focus on the same subject by prohibiting the scanning operation.

  Although the single-lens reflex electronic still camera has been described above, the present invention can also be applied to various cameras such as a silver salt camera that perform a scanning operation when focus detection is impossible. In the above, the case where the CCD line sensor is provided in the focus detection device 40 separately from the imaging device 14 for imaging has been described. However, the phase difference type focus detection is performed on the two-dimensional photoelectric conversion element which is the imaging device 14 for imaging. The present invention can also be applied to a camera that obtains a pair of focus detection image data by setting an area to be used in calculation.

  The correspondence between the claims and the components according to the embodiment will be described. The photoelectric conversion element is the CCD line sensor of the focus detection device 40, the command output means is the AF switch 62, the focus detection means is the focus detection device 40, the determination means, the scan operation control means, the prohibition means, and the lens drive means are control circuits. Each part in 50 corresponds to each. The measuring means corresponds to the scan prohibit timer 56 and the AF switch OFF timer 57. In addition, the above description is an example to the last, and when interpreting invention, it is not limited or restrained at all by the correspondence of the description matter of said embodiment, and the description matter of a claim.

The figure which shows the structural example of the automatic focusing camera by 1st Embodiment. FIG. 1 is a time chart for explaining a focus detection operation associated with ON / OFF of an AF switch by the automatic focus adjustment camera of FIG. FIG. 1 is a time chart for explaining a focus detection operation associated with ON / OFF of an AF switch by the automatic focus adjustment camera of FIG. FIG. 1 is a flowchart for explaining a program that is activated when the power of the automatic focusing camera in FIG. 1 is turned on. The flowchart which shows the detail of the focus adjustment lens drive process of FIG. The flowchart explaining the program started when the full push switch of the automatic focusing camera of FIG. 1 is turned on. It is a figure which shows the structural example of the automatic focus adjustment camera by 2nd Embodiment. FIG. 7 is a time chart for explaining a focus detection operation associated with ON / OFF of an AF switch by the automatic focus adjustment camera of FIG. FIG. 7 is a flowchart for explaining a program that is activated when the power of the automatic focusing camera in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Camera main body 14: Image pick-up device 31b: AF lens 33: AF motor 40: Focus detection apparatus 50: Control circuit 52: Defocus amount calculating part 54: Lens target position calculating part 54: Lens drive signal calculating part 55: Scan operation command section 56: Scan prohibition timer 57: AF switch OFF timer 61: Power switch 62: AF switch 63: Full-press switch 64: AF-S / AF-C changeover switch

Claims (4)

Photoelectric conversion means for imaging a subject through a taking lens and outputting focus detection image data;
Command output means for outputting a focus adjustment command;
A focus detection unit that detects a focus adjustment state of the photographing lens based on focus detection image data output from the photoelectric conversion unit;
Determination means for determining whether focus detection is possible or impossible based on the detection result of the focus detection means;
When the focus adjustment command is output, if the determination unit determines that focus detection is impossible, a scan operation control unit that images the subject with the photoelectric conversion unit while performing a scan operation of the photographing lens;
A prohibiting means for prohibiting the scanning operation for a predetermined time after the focus adjustment command is not output from the command output means;
An automatic focus adjustment camera comprising: a lens driving unit that drives the photographing lens toward a focus position based on a detection result of the focus detection unit when the determination unit determines that the focus detection is possible. . The autofocus camera of claim 1.
If it is determined by the determination means that focus detection is possible while the scanning operation is prohibited by the prohibition means, the lens driving means aligns the photographing lens based on the detection result of the focus detection means. An automatic focusing camera that is driven toward a focal position. The automatic focusing camera according to claim 1 or 2,
While the scanning operation is prohibited by the prohibiting means, it is determined that the focus detection is impossible by the determination means, and when the determination means still determines that focus detection is impossible even after the predetermined time has passed, An automatic focus adjustment camera, wherein the scanning operation control means scans the photographing lens and images the subject by the photoelectric conversion means. The automatic focusing camera according to any one of claims 1 to 3,
The prohibition means is
Time measuring means for measuring an elapsed time after the focus adjustment command is not output from the command output means;
An elapsed time determination means for determining whether or not the elapsed time measured by the measurement means at the time when the focus adjustment command is output again after the focus adjustment command is not output;
The prohibiting means permits the scanning operation of the photographing lens when the elapsed time determining means determines that the elapsed time is equal to or greater than the predetermined time, and the elapsed time determining means determines that the elapsed time is equal to or greater than the predetermined time. An automatic focusing camera, wherein if not determined, the scanning operation of the photographing lens is prohibited.

Images