JP2016142777A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: in an imaging device having a crop shooting function, a distance measuring precision may be lowered as focal point correcting information cannot be obtained from photometric means regarding a distance measuring area that is present outside a crop range masked during cropping.SOLUTION: When a distance measuring area is present in a range masked during crop shooting, focal point correcting data is calculated by photometric means in a photometric area within a crop range that is closest or latest. If an object having moved from the inside to the outside of the crop range has continuity, data being used at the last minute is regarded as correction data. If the object does not have continuity, focal point correcting data is calculated by the photometric means in a closest photometric area.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an imaging apparatus capable of changing an imaging area, and more particularly to correction of a focus detection result in a state where a light shielding mask is displayed on an observation optical system.

  2. Description of the Related Art Conventionally, there is an imaging apparatus equipped with a crop photography function that acquires and records a part of an image with respect to the size of the imaging element. In such a crop photographing function, a function of clearly displaying a photographing region by reducing the luminance of a non-photographing region on a finder that is an observation optical system is known.

  In Patent Document 1, when an imaging apparatus is set to perform crop photography, an imaging that displays a light shielding mask on the observation optical system in accordance with the crop photography mode and controls the transmittance of the light shielding mask in a non-imaging area. An apparatus is disclosed.

  In general, it is known that the position of the focal point is shifted by the light source that illuminates the subject due to the influence of chromatic aberration of the photographing lens.

  In Patent Document 2, an image pickup apparatus that measures a part of a finder beam, which is an observation optical system, by a plurality of photoelectric conversion units having different spectral sensitivity characteristics, detects a light source that illuminates a subject from the output result, and corrects a focus detection result. Is disclosed.

JP 2012-181323 A JP 2000-275512 A

  However, in the prior art disclosed in the above-mentioned patent document, when the transmitted light of the light shielding mask is used when measuring a part of the finder light beam, the output result of the photoelectric conversion means changes depending on the wavelength transmission characteristics of the light shielding mask. To do. For this reason, there is a problem that detection of the light source that illuminates the subject is not properly performed, and the focus detection result is not appropriately corrected.

  Accordingly, an object of the present invention is to provide an imaging apparatus that appropriately performs light source detection correction of a focus detection result even in a distance measurement area existing in a light shielding mask area of an observation optical system.

In order to achieve the above object, the present invention provides:
An imaging apparatus having a crop photography mode for picking up and imaging only a part of the effective area of the imaging means,
At least in the crop photography mode, an observation optical system (101) that transmits part of the imaging region and semi-transmits or shields the other region;
Correction data calculating means (112) for calculating correction data relating to the in-focus position by observing the observation optical system;
Focus detection means (109) for detecting a focal point for focusing the photographing lens on the subject;
Correction means (112) for correcting the in-focus position based on the correction result by the correction data calculation means,
At least in the crop photography mode, when correcting the in-focus position in the distance measurement area outside the part of the image capture area, correction is performed using alternative data other than the correction data calculated in the distance measurement area. Features.

  According to the present invention, in crop imaging in which a part of an image is acquired and recorded, a shooting area is clearly displayed, and a focus detection result is obtained for a distance measurement area existing in a light shielding mask area of the observation optical system. It is possible to provide an imaging apparatus that appropriately performs the light source detection correction.

Schematic diagram showing the schematic configuration of a camera as an imaging device The figure which shows the state of the finder observed from the eyepiece optical system The figure which shows the state of the finder observed from the eyepiece optical system The figure which shows the state of the subject on the finder, the distance measurement area and the photometry area The figure which shows the state of the subject on the finder, the distance measurement area and the photometry area The figure which shows the state of the subject on the finder, the distance measurement area and the photometry area Flow chart showing photographing operation of imaging device Flowchart showing detection operation of photometric means of imaging apparatus Flow chart showing focus adjustment processing of imaging apparatus

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

  The image pickup apparatus according to the first embodiment of the present invention will be described below. FIG. 1 shows a configuration of an imaging apparatus including an observation optical system that is Embodiment 1 of the present invention.

  In FIG. 1, reference numeral 100 denotes an imaging device. 101 is a viewfinder which is an observation optical system, 102 is an eyepiece which is an eyepiece optical system, and 103 is a viewfinder screen.

  Reference numeral 104 denotes a main half mirror (hereinafter referred to as a main mirror) for deflecting the imaging light beam to the finder optical system, and reference numeral 105 denotes a sub mirror for deflecting the imaging light beam to a focus detection unit described later. The main mirror 104 and the sub mirror 105 constitute mirror means that is an optical path dividing optical system.

  Reference numeral 106 denotes an image pickup device such as a CCD sensor or a CMOS sensor constituting the image pickup means, and reference numeral 107 denotes a focal plane shutter that controls exposure of the image pickup device 106.

  Reference numeral 109 denotes a focus detection unit. The focus detection unit 109 has at least a pair of pixel columns (line sensors), and the pair of line sensors photoelectrically converts a pair of images formed by a light beam from the photographing optical system and outputs a signal.

  Reference numeral 110 denotes a photometric sensor for measuring subject luminance, and reference numeral 111 denotes a photometric lens that forms an image of a light flux from the subject on the photometric sensor 110.

  Reference numeral 112 denotes a camera microprocessor that controls various operations of the imaging apparatus 100. In this embodiment, the focal position correction data calculation means (113), the correction means (114), and correction data calculation availability determination means ( 115). Reference numeral 116 denotes a finder display unit that displays various types of information to an observer looking through the optical finder. Reference numeral 117 denotes a low-pass filter disposed in front of the image sensor 106.

  Here, the configuration of the observation optical system will be described. An object image formed on the finder screen 103 which is a focusing screen by the photographing lens 200 passes through the finder display unit 116 disposed in the vicinity of the finder screen 103, and the eyepiece optical system 102. Is observed. The finder screen 103 has a diffusion characteristic. By observing the finder screen 103 with the photometric sensor 110 through the photometric lens 111, the exposure value of the subject and the light source in the distance measurement area are detected, and the subject is tracked. ing.

  The detection of the light source will be described in more detail. The photometric sensor 110 that measures the finder beam uses an IR cut filter or the like as a part of the sensor to output a photometric result in the entire spectral sensitivity range and a photometric result in a state where infrared light is cut. By comparing the results of these outputs, the ratio of the infrared light component of the subject illumination light can be detected, and the light source is detected and the in-focus position is corrected based on the result.

  In this embodiment, the photometric optical system in which the eyepiece optical system is observed from a direction deviated by a predetermined angle is shown. However, a half mirror or the like may be arranged between the eyepiece optical systems to divide the light beam.

  Reference numeral 200 denotes an interchangeable lens that can be attached to and detached from the imaging apparatus 100. The configuration of the interchangeable lens 200 will be described below.

  A lens microprocessor 201 controls various operations of the interchangeable lens 200, and communicates with the camera microprocessor 112 via a communication contact. Reference numeral 202 denotes a lens which is an imaging optical system constituting the photographing optical system, and reference numeral 203 denotes an aperture for adjusting the amount of light. Although only one lens is shown in FIG. 1, in reality, the photographing optical system is composed of a plurality of lenses.

  In this embodiment, the imaging apparatus 100 (camera microprocessor 112) communicates with the interchangeable lens 200 (lens microprocessor 201). Thereby, control is performed using information held by the interchangeable lens 200.

FIG. 2 shows the state of the finder observed from the eyepiece optical system.
As shown in FIG. 2, the image pickup apparatus of the present embodiment has an entire area shooting mode that uses the entire area with respect to the size of the image sensor, and a crop shooting mode that acquires and records a partial image. ing.

  FIG. 2A shows the state of the finder observed from the eyepiece optical system in the whole region mode. Reference numeral 1000 denotes an entire screen area that is an effective area that can be imaged by the imaging apparatus, and reference numeral 1010 denotes an image area that is acquired when recording is performed. In FIG. 2A, the entire screen area is used, and the shooting area 1010 coincides with the entire screen area. For this reason, the mask means displayed by the finder display unit 116 is not displayed.

  Reference numeral 1020 denotes a photometric area, which is an area where the photometric sensor detects the state of the subject image through the photometric optical system. In the present embodiment, an example of 9 × 17 division is shown as the photometry area, but it is not limited to this division. Reference numeral 1030 denotes a distance measurement area, which indicates a visual field range in which the light beam is divided between the focusing screen and the imaging optical system and focus detection is performed by a focus detection system different from the finder optical system. In the case of the entire area mode shown in this drawing, the photometry area 1020 and the distance measurement area 1030 exist inside the imaging area 1010.

  FIG. 2B shows an example of the crop photography mode. At this time, since the shooting area 1010 exists inside the full screen area 1000, there is an area that is not imaged outside the shooting area 1010. In this embodiment, in order to clarify the shooting area, the brightness of the subject image is reduced by graying out the mask area 1040 outside the shooting area 1010 with respect to the inner shooting area 1010 using a light shielding mask. 2B shows an example in which the grayout is displayed with the transmittance of the light shielding mask lowered, but any method may be used such as a method of completely shielding the light.

  When a ranging area exists outside the imaging area as in this embodiment, the following advantages can be considered as an example for focus detection in the ranging area. For example, when focus detection is performed while following the movement of the subject, even if the subject goes out of the cropping range, the subject enters the shooting area again by performing focus detection outside the cropping range. Improvement of follow-up performance is expected. In general, for the focus detection result, correction by photometric information in the observation optical system is effective, and it is effective to improve the focus adjustment tracking accuracy by including this focus detection area outside the imaging area.

  However, as shown in FIG. 2B, in this example, since the photometry area 1020 and the distance measurement area 1030 exist outside the imaging area 1010, detection is performed using the light beam of the finder optical system. In a photometric area, the light quantity to the photometric sensor is reduced, and there is a possibility that the light source cannot be detected.

  Therefore, when the finder optical system is grayed out by the light-shielding mask, the light source detection correction at the in-focus position is performed using the light source detection results of other distance measurement areas.

  FIG. 3 shows the difference in appearance in the observation optical system when the subject is inside and outside the crop area. 3A and 3C, the subject is outside the crop area, and in FIG. 3B, the subject is inside the crop area. Here, reference numeral 1031 denotes a distance measuring area closest to the subject of interest.

  In this example, when the situation shown in FIG. 3A occurs at the start of shooting, light source detection correction data cannot be calculated in the distance measurement area 1031. Therefore, for the focus detection result of the distance measurement area 1031, the focal point position is corrected using the light source detection result in the light measurement area 1021 within the crop range closest to the distance measurement area 1031 as alternative data.

  When the situation shown in FIG. 3B is reached, light source detection correction data is calculated from the photometry result in the photometry area 1021 near the distance measurement area 1031.

  Further, in the situation of FIG. 3 (c), if the situation of FIG. 3 (b) is within a predetermined time, the light source detection result is obtained from the photometry area within the closest cropping range according to FIG. 3 (a). The latest FIG. 3B is more preferable as the light source for illuminating the subject than the substitute data. Therefore, if there is a result of acquiring light source detection correction data within a predetermined time for the same subject, the light source detection result is adopted as alternative data.

  Note that the same subject can be determined by any method, such as automatic camera setting or designation by the photographer.

  In the above example, the example in which the light source of the subject is detected by the observation optical system and the in-focus position is corrected is presented, but the correction of the in-focus position is not limited to that by the light source detection correction. The same applies to the following words.

  FIG. 4 is a flowchart showing the photographing operation of the imaging apparatus.

  In FIG. 4, when the process is started, in step 100 (hereinafter referred to as S100), it is determined whether or not the release SW1 of the imaging apparatus is ON. If it is determined in S100 that SW1 is ON, the process proceeds to the next S120.

  In S120, a photometric processing subroutine is executed, and the light source detection of the subject for the calculation of the proper exposure and the correction of the in-focus position is performed using the output of the photometric sensor. After executing the process in S120, the process proceeds to the next S130.

  In S130, it is determined whether the focus adjustment mode of the imaging apparatus is manual or auto. If it is auto, the process proceeds to the next S140.

  In S140, a focus adjustment processing subroutine is executed, and the in-focus position of the subject in the distance measurement area is calculated. As will be described later, in-focus position correction using the light source detection correction data obtained in S120 is also performed here. After performing the process of S140, the process proceeds to the next S150.

  In S150, it is determined whether or not the release SW1 of the imaging apparatus is ON. If it is OFF, it is determined that the shooting operation has been canceled, and the process returns to S100. If it is ON, the process proceeds to S160.

  In S160, it is determined whether or not the release SW2 of the imaging apparatus is ON. If it is ON, the process proceeds to the next S170.

  In S170, an imaging process is executed. After the imaging process is executed, the process proceeds to the next S180.

  In S180, it is determined whether the shooting mode of the imaging apparatus is the continuous shooting mode. If it is in the continuous shooting mode, it is determined in S190 whether the release SW2 is ON. If it is ON, the processing from S120 is executed again. If the continuous shooting mode is not set in S180, or if the release SW2 is OFF in S190 even in the continuous shooting mode, the shooting operation is terminated.

  FIG. 5 is a flowchart showing the photometric processing operation of the imaging apparatus, which corresponds to S120 described above.

  In S300, it is determined whether or not the shooting operation is the crop shooting mode. If it is the crop photography mode, the process proceeds to the next S310, and if not, the process proceeds to S323.

  In S310, it is determined whether or not the focus detection area focused on the current shooting is outside the cropping range. When the distance measurement area is outside the cropping range, the process proceeds to the next S320, and otherwise, the process proceeds to S323.

  In S320, it is determined whether a light source detection result of the same subject as that of the subject in the distance measurement area of interest is acquired within a predetermined time before the current photographing process. Here, there is no limitation on the method for determining whether the subject is the same subject. When it has been acquired, the process proceeds to S321, and when it has not been acquired, the process proceeds to S322.

  S321 to S323 are flags relating to the handling of the light source detection correction data. In S321, since it is determined that the light source detection result of the same subject as the subject in the distance measuring region of interest is acquired within a predetermined time before the current photographing process, the data is adopted. As correction is performed, the process proceeds to S340. In S322, since there is no light source detection data within the predetermined time for the same subject, light source detection is performed in the field of view within the latest crop range, and correction data is calculated in S330. In S323, since the focused distance measurement area can perform light source detection, correction data is calculated in S330.

  In S330, correction data for the focal position by light source detection is calculated by the above-described processing. After the correction data is calculated, the process proceeds to the next S340.

  In S340, it is determined whether the exposure adjustment mode of the imaging apparatus is manual or auto. If it is auto, the process proceeds to the next S350.

  In S350, the appropriate exposure at the time of shooting is calculated, and the photometric processing operation is terminated.

  FIG. 6 is a flowchart showing the focus adjustment process of the imaging apparatus. The processing here is described by focusing on the correction of the in-focus position, and the description of the focus detection processing including the determination of the selection mode of the ranging area and the in-focus determination may be omitted.

  In S400, focus detection processing is performed. Thereafter, the process proceeds to S410.

  In S410, the presence / absence of light source detection correction data is determined. If there is light source detection correction data, the focus detection result in S400 is corrected in S420, and the process proceeds to S430.

  In S430, the lens is driven based on the focus detection result and the correction result, and the focus adjustment process is terminated.

100 imaging device, 101 observation optical system, 102 eyepiece optical system,
103 finder screen, 104 main half mirror, 105 sub mirror,
106 image sensor, 107 focal plane shutter, 109 focus detection unit,
110 photometric sensor, 111 photometric lens, 112 camera microprocessor,
116 finder display unit, 117 low-pass filter, 200 photographing lens,
201 lens microprocessor, 202 photographing optical system, 203 stop,
1000 full screen area, 1010 shooting area, 1020 metering area,
1021 Photometry area near the subject of interest, 1030 Distance measurement area,
1031 Ranging area near subject of interest, 1040 Mask area

Claims (5)

An imaging device having a crop photography mode that picks up an image by selecting only a part of the first area as an imaging area relative to an effective area of the imaging means,
At least in the crop photography mode, an observation optical system (101) that transmits the first area and semi-transmits or shields a second area that is outside the first area while being an effective area of the imaging means;
Photoelectric conversion means (110) for detecting a light beam of the observation optical system;
Correction data calculating means (113) for calculating correction data relating to the focal position of the focus range of interest based on the output of the photoelectric conversion means;
A focus detection means (109) for detecting the focal point of the distance measuring area in order to focus the photographing lens on the subject;
Correction means (114) for correcting the in-focus position based on the correction result by the correction data calculation means,
At least in the crop photography mode, when correcting the focal position in the distance measurement area of the second imaging area, the correction of the focal position in the distance measurement area is calculated in the first imaging area. An image pickup apparatus using correction data. A subject recognizing unit for recognizing the same subject for a certain period of time for a subject in the ranging area; and a determination unit for determining the presence / absence of correction data calculated by the correction data calculating unit within a predetermined time; When it is determined that there is correction data calculated within a predetermined time by the determination unit with respect to a subject recognized as the same subject by the subject recognition unit, the correction data is stored in the distance measurement area. The imaging apparatus according to claim 1, wherein the imaging apparatus is used as substitute data. As the alternative data, the focal point position correction is performed using the calculation result of the correction data in the part of the photographing area within a predetermined range from the distance measurement area outside the part of the photographing area. The imaging apparatus according to claim 1. The imaging apparatus according to claim 1, wherein the correction data is calculated based on a detection result of a light source that illuminates a subject. The imaging apparatus according to claim 4, wherein the light source is detected based on a photometric result of an observation optical system.