JP2016173443A - Imaging device and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of photographing an image focused on a main subject even when the main subject as a tracking target in continuous photographing moves out of an effective range of a photometric sensor or an AF sensor during continuous photographing.SOLUTION: The imaging device includes: an imaging element; ranging means by another imaging element different from the above imaging element; photometric means by a photometric sensor; an optical finder for optically displaying a subject without using the imaging element; an electronic view finder displaying a photographed image obtained by photographing means; subject detection means for detecting a position of the subject based on an image signal obtained from the imaging element or the photometric sensor; and tracking means for tracking the subject detected by the subject detection means. The imaging device includes control means that switches between the ranging means and a ranging operation by the imaging element based on the positional information of the subject detected by the subject detection means, and simultaneously switches the optical finder and the electronic view finder in a finder display.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus typified by a digital camera, and more particularly to control of autofocus during tracking shooting of an imaging apparatus equipped with a finder having both an optical viewfinder and an electronic viewfinder.

  Conventionally, in a single-lens reflex camera equipped with an optical viewfinder, the subject can be viewed only by the optical viewfinder in the viewfinder, and the subject cannot be seen by the viewfinder while the mirror is raised. However, in recent years, there has been proposed a camera that can switch between an optical viewfinder and an electronic viewfinder.

  Patent Document 1 discloses an imaging apparatus that can superimpose and display or switch between an optical viewfinder and an electronic viewfinder while observing through a common viewfinder. If the optical viewfinder and electronic viewfinder can be switched in the same optical path, the normal optical viewfinder can be used for the posture of the photographer looking into the camera viewfinder in live view display shooting and movie shooting using the electronic viewfinder. It is the same as it was. Therefore, it is possible to perform shooting while holding the camera in an ideal position.

  Also, in continuous photo shooting with a camera, there is a subject tracking function that can track AE (automatic exposure) and AF (autofocus) even if the tracking subject moves by tracking a specific subject to be shot. The number of on-board electronic cameras is increasing. Patent Document 2 discloses an imaging apparatus that performs subject tracking using photometric image data.

JP 2010-135894 JP 2013-200530

  However, the conventional technique disclosed in the above-described patent document has a problem that the range in which the subject can be tracked is within the effective area of the AF sensor, and tracking cannot be performed over the entire angle of view. This is because when such subject tracking is performed, a single-lens reflex camera often performs tracking by acquiring an image signal with a photometric sensor in the penta portion immediately before shooting and processing the image signal. Further, since the range where the subject can be focused is the effective range of the AF sensor, it can be said that the subject range where the subject tracking function can shoot an image focused on the tracking subject depends on the effective range of the AF sensor.

  That is, since the effective area of the AF sensor is smaller than the angle of view, tracking cannot be performed over the entire angle of view. Therefore, even when the tracking subject is within the angle of view, if the AF sensor is out of the effective range, focusing by tracking cannot be performed, and there is a problem that an image that is not in focus is captured. FIG. 3 is an example of a captured image at the time of tracking continuous shooting. Images are taken in the order of (A), (B), (C). In (A) and (B), since the tracking subject is within the effective range of the AF sensor, an image focused on the subject can be taken. In C), since the tracking subject is out of the effective range of the AF sensor, the subject is not in focus. However, as shown in FIG. 4 as an example of the effective area of the AF sensor and the effective area of the imaging surface AF, the imaging surface AF can perform AF over the entire angle of view. If subject tracking is performed with the image sensor, the subject tracking range can be expanded.

  An object of the present invention is to provide an imaging apparatus capable of capturing an image focused on a tracking subject even when the subject to be tracked deviates from the effective range of the AF sensor during continuous photography. is there.

In order to achieve the above object, an imaging apparatus of the present invention provides:
An image sensor;
Distance measuring means using an image sensor different from the image sensor;
Photometric means by a photometric sensor;
An optical viewfinder that optically displays a subject image without going through the image sensor;
An electronic viewfinder for displaying a captured image obtained by the imaging means;
Subject detection means for detecting the position of the subject based on the image signal obtained from the image sensor or the photometric sensor;
Tracking means for tracking the subject detected by the subject detection means,
Control means for switching between the distance measuring means and the distance measuring operation by the image sensor based on the position information of the subject detected by the subject detecting means, and simultaneously switching the optical viewfinder and the electronic viewfinder for display of the viewfinder. It is characterized by having.

  According to the present invention, it is possible to widen the tracking range of a subject during continuous photography with the subject tracking function. In addition, with a single-lens reflex camera that allows switching between optical viewfinder and electronic viewfinder, even if switching from normal shooting to mirror-up shooting, switching from optical viewfinder to electronic viewfinder allows the photographer to shoot with the same posture. It can be carried out.

Flow chart of the present invention Camera system configuration diagram Example of effective area of AF sensor and effective area of imaging surface AF Examples of images shot during tracking continuous shooting

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Example 1]
The first embodiment of the present invention will be described below. FIG. 2 is a diagram showing the configuration of the camera system according to the first embodiment of the present invention.

  Reference numeral 100 denotes a camera body, and 200 denotes a lens. A configuration in the camera body 100 will be described. A microcomputer CPU (hereinafter referred to as a camera microcomputer) 101 controls each part of the camera 100. Reference numeral 102 denotes a memory such as a RAM or a ROM connected to the camera microcomputer 101. Reference numeral 103 denotes an image sensor such as a CCD or a CMOS including an infrared cut filter, a low-pass filter, and the like.

  A shutter 104 shields the image sensor 103 when not photographing, and opens to guide the light beam to the image sensor 103 when photographing. A half mirror 105 reflects a part of light incident from the lens 200 when not photographing, and forms an image on the focusing plate 106. Reference numeral 107 denotes a display element for displaying an AF distance measurement frame such as a PN liquid crystal, which indicates to the user at which position AF is performed when looking through the optical viewfinder. Reference numeral 108 denotes a photometric sensor, which performs not only photometry but also face detection and tracking by using an image sensor such as a CCD or CMOS.

  A pentaprism 109 guides the subject image on the focusing screen 106 to the photometric sensor 108 and the optical viewfinder. The photometric sensor expects a subject image formed on the focus plate 106 via a pentaprism from an oblique position. Reference numeral 110 denotes a focus detection circuit, which is an AF mirror 111. A part of the light beam incident from the lens and passed through the half mirror 105 is guided to an AF sensor in the focus detection circuit 110 for distance measurement. Reference numeral 112 denotes a CPU for driving control of the photometric sensor 108 and image processing / calculation (hereinafter referred to as ICPU), which performs photometric calculation, face detection calculation, tracking calculation, electronic viewfinder display control, and the like.

  Reference numeral 113 denotes a memory such as a RAM or a ROM connected to the ICPU 112. Reference numeral 114 denotes a display device used for the electronic viewfinder. Reference numeral 115 denotes a display prism for superimposing the optical viewfinder and the electronic viewfinder.

  This is the end of the description of the configuration diagram of the camera system according to the embodiment of the present invention shown in FIG.

  Next, the flowchart of the digital single-lens reflex camera which is embodiment of this invention is demonstrated using FIG.

  Step S101 indicates holding of SW1 before the start of tracking continuous shooting. SW1 indicates a state where the release button is half-pressed. AE and AF are started by holding SW1. In step S102, AE and AF processes are performed by the photometric sensor and AF sensor. In step S103, it is determined whether SW2 is pressed. SW2 indicates a state where the release button is fully pressed. If SW2 is pressed, the process proceeds to the next S104. If SW2 is not pressed and SW1 is held, the process returns to S102, and the AE and AF processes are performed again.

  In step S104, AE and AF processes before photographing are performed. The AE and AF are used to determine shooting conditions such as aperture value, shutter speed, and ISO value, and to determine the tracking subject. In step S105, the coordinates of the tracking subject are calculated and acquired. In step S106, the mirror 105 is retracted from the incident light path so that the light beam is guided to the image sensor when the shutter travels. In step S107, the shutter is run under the conditions determined in S104, the light beam taken from the lens is guided to the image sensor, and a photographing operation is performed.

  In step S108, it is determined whether or not the coordinates of the tracking subject acquired in S105 are within a predetermined range. In the present embodiment, the predetermined range is the effective range of the AF sensor. When the tracking subject is within the effective range of the AF sensor, it can be predicted that the tracking subject will be in focus even during the next shooting. However, when the tracking subject is out of the effective range of the AF sensor, it is conceivable that the tracking subject is not focused on the next shooting. Therefore, when the tracking subject is out of the effective range of the AF sensor, the AF means is switched from the AF sensor to the imaging surface AF. When the tracking subject is out of the effective range of the AF sensor, by switching to the imaging surface AF, AF can be performed within the angle of view, and the tracking subject can be focused.

  The operation after branching depending on whether the tracking subject is within a predetermined range will be described below. First, the operation when the tracking subject is within the effective range of the AF sensor will be described. If the subject is within the effective range of the AF sensor in S108, the process proceeds to S109. In step S109, the mirror is lowered and the light beam taken from the lens is guided to the optical viewfinder. In step S110, it is determined whether SW2 is held. If SW2 is ON, the process returns to S104 and the operations of S104 to S110 are repeated. When SW2 is OFF, the process proceeds to S201, and the tracking continuous shooting is finished.

  Next, the operation when the tracking subject is out of the predetermined range in S108 will be described. If the subject is within the effective range of the AF sensor in S108, the process proceeds to S111. In step S111, the mirror-up state is maintained even after shooting is completed, and the viewfinder display is switched from the optical viewfinder to the electronic viewfinder. By switching to the electronic viewfinder, the photographer can take a picture while looking at the subject in the viewfinder without changing the posture even when the mirror is raised.

  In step S112, it is determined whether SW2 is held. If SW2 is ON, the process proceeds to S114. When SW2 is OFF, the process proceeds to S201, and the tracking continuous shooting is finished. In step S113, imaging surface AE / AF processing is performed. In step S114, mirror-up shooting is performed. Thereafter, the process returns to S112 to determine whether SW2 is held, and S113 and S114 are repeated while SW2 is ON. However, when the tracked subject once deviates from the predetermined range and then enters the predetermined range, the normal shooting with mirror down may be returned.

  This is the end of the description of the flowchart of the digital single-lens reflex camera according to the embodiment of the present invention.

  As described above, according to the present invention, the tracking range of a subject can be expanded during continuous shooting with the subject tracking function. In addition, in a single-lens reflex camera equipped with a viewfinder that has both an optical viewfinder and an electronic viewfinder, the photographer switches by switching from normal shooting with the mirror down to mirror-up shooting and at the same time switching from the optical viewfinder to the electronic viewfinder. Can shoot without looking through the viewfinder. Further, in the distance measurement by the AF sensor and the imaging surface AF, since the distance measurement operation by the AF sensor is faster, there is a merit in performing the normal photographing when the tracking subject is within the effective range of the AF sensor.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

100 cameras, 101 camera microcomputers, 102 memories, 103 image sensors,
104 shutters, 105 half mirrors, 107 ranging frame display elements,
108 photometric sensor, 110 focus detection circuit, 112 CPU for image processing / calculation,
113 Memory, 114 Display device for electronic viewfinder, 115 Display prism,
200 lens, 201 lens microcomputer

Claims (2)

An image sensor (103);
Ranging means (110, 111) using an image sensor different from the image sensor;
Photometric means (108) by a photometric sensor;
An optical viewfinder (105, 106, 109) for optically displaying a subject image without going through the image sensor;
An electronic viewfinder (114, 115) for displaying a captured image obtained by the imaging means;
Subject detection means (112) for detecting the position of the subject based on an image signal obtained from the image sensor or the photometric sensor;
Tracking means (112) for tracking the subject detected by the subject detection means,
Control means for switching between the distance measuring means and the distance measuring operation by the image sensor based on the position information of the subject detected by the subject detecting means, and simultaneously switching the optical viewfinder and the electronic viewfinder for display of the viewfinder. 101, 112). Computing means (112) for calculating the amount of movement of the tracking subject,
The photographing apparatus according to claim 1, further comprising a control unit (112) that controls a determination threshold value for switching between AF by the AF sensor and imaging surface AF based on a movement amount of the tracking subject calculated by the calculation unit.