Imaging device and method of controlling imaging device

Patent metadata

Field	Value
Publication number	US-10775680-B2
Application number	US-201916572959-A
Country	US
Kind code	B2
Filing date	Sep 17, 2019
Priority date	Mar 30, 2017
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

There are provided an imaging device and a method of controlling the imaging device that can shorten the blackout period of a live view image in a case where a front curtain and a rear curtain are moved to continuously take static images. In a case where continuous shooting is performed, a focal-plane shutter is shifted to a normally open state to allow a live view image to be displayed during the continuous shooting. A front curtain-electromagnet and a rear curtain-electromagnet are excited to prevent the rotational movement of a second front curtain-drive lever and a second rear curtain-drive lever in a first direction after the focal-plane shutter is shifted to the normally open state; first curtain travel preparation for causing the second front curtain-drive lever and the rear curtain-drive lever to be moved to non-charge positions from charge positions is performed to release the prevention of the travel of the front curtain in a closing direction, which is performed by the front curtain-locking lever, from a point of time later than a point of time when the first curtain travel preparation is to be started; and second curtain travel preparation for causing the front curtain to travel in the closing direction to fully close an exposure aperture portion is performed.

First claim

What is claimed is:

1. An imaging device comprising:
a focal-plane shutter;
an imaging element; and
a control unit that controls the focal-plane shutter and the imaging element,
wherein the focal-plane shutter includes a front curtain, a front curtain-drive member, a rear curtain, a rear curtain-drive member, a charge member, a lock mechanism that holds the front curtain-drive member and the rear curtain-drive member at charge positions, a front curtain-locking member that prevents travel of the front curtain in a closing direction, and a front curtain-electromagnetic actuator and a rear curtain-electromagnetic actuator that directly or indirectly prevent drive of the front curtain-drive member and drive of the rear curtain-drive member, by excitation,
in a case where second and later static images in a continuous shooting mode are to be taken, the control unit performs:
normally open control that makes the focal-plane shutter be in a normally open state, after reading of an image signal corresponding to the static image from the imaging element ends;
first curtain travel preparation that excites the front curtain-electromagnetic actuator and the rear curtain-electromagnetic actuator and releases holding by the lock mechanism, after shifting to the normally open state;
second curtain travel preparation that releases lock of the front curtain by the front curtain-locking member, and causes the front curtain to travel in the closing direction to fully close an exposure aperture portion, after the first curtain travel preparation; and
exposure control that causes the front curtain to travel in an opening direction after completion of the second curtain travel preparation, and causes the rear curtain to travel in the closing direction after a lapse of an exposure time corresponding to a shutter speed, to perform exposure corresponding to the static image, and
the image signal is read from the imaging element in a period until the exposure aperture portion is closed by the second curtain travel preparation after the exposure aperture portion is opened by the shift of the focal-plane shutter to the normally open state, and a live view image is allowed to be displayed during a continuous shooting-repetition period until a point of time when exposure of the next static image is started from a point of time when exposure of each of the static images continuously taken in the continuous shooting mode is started.

2. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes an image signal for distance measurement,
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element and calculates distance measurement information on the basis of the acquired image signal for distance measurement, and
the control unit performs the first curtain travel preparation during exposure of the image signal for distance measurement.

3. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes an image signal for distance measurement that is to be exposed for distance measurement,
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element and calculates distance measurement information on the basis of the acquired image signal for distance measurement, and
the control unit performs the first curtain travel preparation after the completion of exposure of the image signal for distance measurement.

4. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes an image signal for distance measurement that is to be exposed for distance measurement, and
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element after the completion of the first curtain travel preparation and calculates distance measurement information on the basis of the acquired image signal for distance measurement.

5. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes image signals for distance measurement of a plurality of frames that are to be exposed for distance measurement,
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element, calculates distance measurement information on the basis of the acquired image signal for distance measurement, and acquires the image signals for distance measurement of the plurality of frames in a time-series order until distance measurement information exceeding a reliability-determination value is acquired, and
the control unit performs the second curtain travel preparation in a case where the distance measuring unit acquires the distance measurement information exceeding the reliability-determination value.

6. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes an image signal for distance measurement that is to be exposed for distance measurement,
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element and calculates distance measurement information on the basis of the acquired image signal for distance measurement, and a lens drive time-calculating unit that calculates a lens drive time required for driving of a focus lens on the basis of the calculated distance measurement information, and
the control unit compares the calculated lens drive time with a time required for the second curtain travel preparation, calculates an imaging timing when the exposure control of the static image is to be started on the basis of the lens drive time in a case where the lens drive time is equal to or longer than the time required for the second curtain travel preparation, and starts the second curtain travel preparation at a time ahead of the calculated imaging timing by the time required for the second curtain travel preparation.

7. The imaging device according to claim 1 ,
wherein the image signal for the display of the live view image, which is read from the imaging element during the continuous shooting-repetition period in the continuous shooting mode, includes an image signal for distance measurement that is to be exposed for distance measurement,
the imaging device further comprises a distance measuring unit that acquires the image signal for distance measurement from the imaging element and calculates distance measurement information on the basis of the acquired image signal for distance measurement, and a lens drive time-calculating unit that calculates a lens drive time required for driving of a focus lens on the basis of the calculated distance measurement information, and
the control unit compares the calculated lens drive time with a time required for the second curtain travel preparation, calculates an imaging timing when the exposure control of the static image is to be st

Assignees

• Fujifilm Corp

Inventors

• Irie Fuminori

Classifications

• H04N23/50

  Constructional details · CPC title

• H04N23/63

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• H04N23/55

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• H04N23/75

  by influencing optical camera components · CPC title

• H04N23/65

  Control of camera operation in relation to power supply · CPC title