JP2006030470A - Autofocus camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autofocus camera which displays an irradiation range of AF auxiliary light in emitting the AF auxiliary light by an auxiliary light emitting apparatus. <P>SOLUTION: In the electronic camera, a visual target 24 showing the irradiation range of the AF auxiliary light is displayed on a display apparatus while overlapping the visual target 24 on a through image in a state where the AF auxiliary light should be emitted (in a state where object brightness is below a level required for a contrast AF processing). In the electronic camera, the size of the visual target 24 is changed in accordance with a zoom position. When the AF area lies within the irradiation range of the AF auxiliary light (that is, inside the visual target 24), an icon 25 showing the emission of the AF auxiliary light is displayed, and also, the display mode of a target 22 showing the AF area is changed (22B). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an autofocus camera that detects a focus adjustment state by irradiating auxiliary light.

  A camera that detects a focus adjustment state by irradiating auxiliary light onto a dark subject is known (see Patent Document 1). According to Japanese Patent Application Laid-Open No. 2004-133620, an area having a brightness of a predetermined level or higher by irradiation of auxiliary light is used as an area (AF area) for detecting a focus adjustment state among the shooting screens divided into a plurality of areas.

JP 2001-128056 A

  Since it is difficult to provide a general camera with an auxiliary light source having a wide irradiation angle and a large amount of light, the irradiation range of the auxiliary light is usually narrower than that of the photographing screen. The camera described in Patent Document 1 automatically adopts an area having a brightness of a predetermined level or more when auxiliary light is irradiated as an AF area, but the AF area adopted by the camera is not necessarily the AF area desired by the photographer. Is not limited. When the AF area is configured to be arbitrarily designated, there is a possibility that the photographer designates an AF area that is outside the irradiation range of the auxiliary light.

The present invention is applied to an autofocus camera that acquires focus adjustment information corresponding to a focus area designated at any position in a shooting screen and performs focus adjustment based on the acquired focus adjustment information. A light emitting unit that emits illumination light toward a partial area in a shooting screen when information is acquired, and a composite display unit that displays at least an illumination range of the light emitting unit on a subject image before instructing shooting And
The autofocus camera may be configured by an electronic camera including an image sensor, and the subject image in this case is a through image displayed on the display device.
The subject image may be an optical image by an optical viewfinder.
The composite display means of the autofocus camera may display the position of the designated focus area so as to overlap the subject image. In this case, the autofocus camera further has the focus area positioned within the illumination range of the light emitting means. Display control means for controlling the composite display means to display the position of the focus area in a different manner depending on whether or not to do so can also be provided.
The autofocus camera may further include a limiting unit that limits a designated position of the focus area within an illumination range by the light emitting unit.
The composite display unit of the autofocus camera according to the present invention can change the illumination range to be displayed according to the focal length of the photographing lens.

  In the autofocus camera according to the present invention, since the range in which the auxiliary light is irradiated is displayed, the possibility that the AF area outside the irradiation range is erroneously designated is reduced.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of an electronic camera according to a first embodiment of the present invention. In FIG. 1, an electronic camera includes a photographing lens 1, an image sensor 2, an image processing circuit 3, a display device 4, a backlight 5, a memory 7, an operation member 8, a focus control mechanism 9, and zoom control. A mechanism 10, a CPU 11, and an auxiliary light device 12 are included.

  The taking lens 1 has a zoom lens 1a and a focus lens 1b. The zoom lens 1a is driven back and forth in the optical axis direction by the zoom control mechanism 10. As the zoom lens 1a is driven forward and backward, the shooting angle of view changes. The focus lens 1b is driven back and forth in the optical axis direction by the focus control mechanism 9. The focus lens 1b is driven forward and backward to adjust the focus of the photographing lens 1.

  The image sensor 2 is constituted by a CCD or the like. The imaging device 2 captures a subject image formed on the imaging surface and outputs an imaging signal. The image processing circuit 3 performs predetermined image processing after converting the analog imaging signal into a digital signal. The image processing circuit 3 further generates a video signal using the image data after the image processing and sends it to the display device 4, or converts the format of the image data into a predetermined data format.

  The display device 4 is constituted by a transmissive liquid crystal display panel, and reproduces and displays an image by a video signal input from the image processing circuit 3. The display image includes a through image that is sequentially captured by the image sensor 2 before the shooting instruction, a still image that is captured by the image sensor 2 after the shooting instruction, and a reproduced image that is based on the image data recorded in the memory 7. The backlight 5 illuminates the display device 4 from behind.

  The memory 7 is composed of a removable memory card or the like. In the photographing mode, the memory 7 records the image data whose format has been converted by the image processing circuit 3. In the reproduction mode, the image data recorded in the memory 7 is read and sent to the image processing circuit 3. The image processing circuit 3 generates a video signal for displaying a reproduced image. The image processing circuit 3 is configured to generate display information such as text, marks and icons, and visual targets to be displayed over the image.

  The operation member 8 includes a power switch (main switch), a zoom switch, a setting switch, a half-press switch, a release (full-press) switch, and the like, and generates an operation signal corresponding to each operation and sends it to the CPU 11.

  The focus control mechanism 9 drives and controls the focus lens 1b according to a command from the CPU 11. The zoom control mechanism 10 drives and controls the zoom lens 1a in response to a command from the CPU 11.

  The CPU 11 outputs a command to each block according to the operation signal input from the operation member 8 and controls the camera operation. The auxiliary light device 12 has an LED as a light emitter, and when the subject brightness is low, the LED is turned on according to a command from the CPU 11 to illuminate the subject, and assists in contrast detection AF described later. The auxiliary light device 12 is configured to illuminate a subject located mainly in the center of the photographing screen.

  The contrast detection AF will be described. The CPU 11 acquires the contrast information of the image signal output from the image sensor 2 while scanning the focus lens 1b for at least a part of the range from the closest end position to the infinity end position, and acquires the focus lens position and the image. Find the relationship with the contrast of the signal. The focus lens position is obtained from the position information of the focus lens 1b input from the focus control mechanism 9. The CPU 11 sets the focus lens position corresponding to the maximum contrast value as the in-focus position, and drives the focus lens 1b to the in-focus position. Such an autofocus adjustment method is called contrast detection AF.

  The CPU 11 is configured to be able to detect contrast information from an image signal corresponding to an area (AF area) designated in advance on the shooting screen during contrast detection AF. FIG. 2 is a diagram for explaining a display example by the display device 4. In FIG. 2, a through image is displayed on the display device 4. A visual target 21 for assisting framing by being superimposed on the through image, a visual target 22 indicating the AF area, and a bar display 23 indicating the zoom state are respectively displayed.

  The visual target 22 is displayed in correspondence with the position of the AF area designated for the electronic camera. FIG. 2 shows a display example when the AF area is designated at the center of the shooting screen. When the camera is set to perform the single ranging AF operation, the CPU 11 performs focus adjustment so that the contrast of the image corresponding to one AF area designated in advance is maximized. The operation of designating the AF area at an arbitrary position on the photographing screen is performed by the photographer operating the operation member 8.

  The bar display 23 is shorter as the zoom lens 1a is operated to the wide (W) side, and is displayed longer as the zoom lens 1a is operated to the tele (T) side. FIG. 2 shows a display example when the zoom lens 1a is located at the center of the wide end and the tele end.

  The present invention is characterized in that the irradiation range is displayed when the auxiliary light device 12 of the electronic camera emits AF auxiliary light.

  The flow of camera processing performed by the CPU 11 of the electronic camera will be described with reference to the flowchart of FIG. The program according to FIG. 3 is repeatedly performed when the electronic camera is set to the photographing mode by the operation member 8. In step S11 of FIG. 3, the CPU 11 acquires the BV value and proceeds to step S12. Specifically, the subject brightness is calculated based on the output value of the image signal output from the image sensor 2.

  In step S12, the CPU 11 determines whether or not the BV value is the AF auxiliary light emission level. If the BV value is less than the predetermined luminance value necessary for performing the contrast AF process, the CPU 11 makes an affirmative decision in step S12 and proceeds to step S13. If the BV value is higher than the predetermined luminance value, the CPU 11 performs step S12. Is negatively determined, and the process proceeds to step S21. The process proceeds to step S13 when the AF auxiliary light is emitted during the photographing process, and the process proceeds to step S21 when the AF auxiliary light is not emitted during the photographing process. Since the present invention is characterized by the operation when emitting AF auxiliary light, the operation when proceeding to step S13 will be mainly described.

  In step S13, the CPU 11 acquires the position information of the AF area and proceeds to step S14. The CPU 11 is configured to change the position of the AF area on the photographing screen in accordance with a designated operation signal from the operation member 8 and store the latest position information of the AF area in the CPU 11. When the operation signal designating the position of the AF area is not input from the operation member 8, the CPU 11 sets the position indicated by the position information stored in the CPU 11 as the position of the AF area.

  In step S14, the CPU 11 acquires the zoom position and proceeds to step S15. The zoom position (zoom lens position) is obtained from the position information of the zoom lens 1a input from the zoom control mechanism 10. In step S15, the CPU 11 calculates the irradiation range of the AF auxiliary light from the zoom position, and proceeds to step S16. The irradiation range in this case is the illumination range of the auxiliary light device 12 that occupies the through image. Since the shooting angle of view becomes narrow when zooming up, the irradiation range of the AF auxiliary light occupying the through image becomes relatively wide. At the time of zooming down, the shooting angle of view becomes wide, so that the irradiation range of the AF auxiliary light occupying the through image becomes relatively narrow.

  In step S16, the CPU 11 determines whether or not the position of the AF area is within the irradiation range of the AF auxiliary light. When the position of the AF area is included in the AF auxiliary light irradiation range in the through image, the CPU 11 makes a positive determination in step S16 and proceeds to step S17. When the position of the AF area is not included in the AF auxiliary light irradiation range In step S16, a negative determination is made, and the process proceeds to step S19.

  In step S <b> 17, the CPU 11 instructs the image processing circuit 3 to display an icon indicating that the AF auxiliary light is lit on the through image, and proceeds to step S <b> 18. It is also instructed to display a visual target or the like indicating the irradiation range of the AF auxiliary light. Thereby, the image processing circuit 3 generates an icon, a target, and the like and superimposes them on the video signal. In step S19, the CPU 11 instructs the image processing circuit 3 to display the AF area target so as to be superimposed on the through image, and proceeds to step S21. Thereby, the image processing circuit 3 generates a target indicating the AF area and superimposes it on the video signal.

  FIG. 4 is a diagram illustrating an example of a screen displayed on the display device 4 at the time when the process proceeds from step S18 to step S21. 4 is the same as FIG. 2 in that a target 21 for assisting framing, a target 22B indicating an AF area, and a bar display 23 indicating a zoom state are displayed. 4, the target 22B is displayed in a different color from the target 22 (FIG. 2) (for example, the target 22B is displayed in red with respect to the white display of the target 22), and the irradiation range of the AF auxiliary light And an icon 25 indicating that the AF auxiliary light is turned on. In FIG. 4, the through image illustrated in FIG. 2 is omitted in order to make it easier to see the target and the like.

The visual target 24 indicating the irradiation range of the AF auxiliary light is
(1) The BV value is the AF auxiliary light emission level (when the photographing process is started, the AF auxiliary light is turned on during the AF process),
(2) The irradiation range of the AF auxiliary light in the through image is shown.

The icon 25 indicating AF auxiliary light lighting is
(1) that the BV value is the AF auxiliary light emission level;
(2) Indicates that the designated AF area is included in the irradiation range of the AF auxiliary light.

The AF area target 22B displayed in the target 24 at the AF auxiliary light emission level is:
(1) that the BV value is the AF auxiliary light emission level;
(2) Indicates that the designated AF area is included in the irradiation range of the AF auxiliary light.

  In step S19, the CPU 11 instructs the image processing circuit 3 to display an icon indicating that the AF auxiliary light is extinguished on the through image, and proceeds to step S20. It is also instructed to display a visual target or the like indicating the irradiation range of the AF auxiliary light. Thereby, the image processing circuit 3 generates an icon, a target, and the like and superimposes them on the video signal. In step S20, the CPU 11 instructs the image processing circuit 3 to display the AF area target on the through image, and proceeds to step S21. Thereby, the image processing circuit 3 generates a target indicating the AF area and superimposes it on the video signal.

  FIG. 5 is a diagram for explaining an example of a screen displayed on the display device 4 when the process proceeds from step S20 to step S21. 5 is the same as FIG. 2 in that a target 21 for assisting framing, a target 22 indicating an AF area, and a bar display 23 indicating a zoom state are displayed. In FIG. 5, a target 24 indicating the irradiation range of the AF auxiliary light and an icon 25B indicating that the AF auxiliary light is turned off are further displayed. In FIG. 5, the through image illustrated in FIG. 2 is omitted in order to make it easier to see the target and the like.

An icon 25B indicating that the AF auxiliary light is turned off is
(1) AF auxiliary light emission level (when the photographing process is started, the AF auxiliary light is turned on during the AF process);
(2) Indicates that the designated AF area is outside the AF auxiliary light irradiation range.

  The AF area target 22 displayed outside the target 24 at the AF auxiliary light emission level indicates that the designated AF area is outside the irradiation range of the AF auxiliary light.

  In step S21 in FIG. 3, the CPU 11 determines whether or not the photographing process is on. When the release operation signal is input from the operation member 8, the CPU 11 makes a positive determination in step S21 and proceeds to step S22. When the release operation signal is not input, the CPU 11 makes a negative determination in step S21 and returns to step S11. Returning to step S11 is a case where the photographer performs an AF area position designation (position change) operation or a zoom change operation.

  6, 7 and 8 are diagrams for explaining the relationship between the zoom position and the irradiation range of the AF auxiliary light. FIG. 6 is a diagram illustrating an example of a screen displayed on the display device 4 when the zoom position is at the wide (W) end. In FIG. 6, a target 21 for assisting framing, a target 22 indicating an AF area, a bar display 23 indicating a zoom state, and an icon 25B indicating turning off AF auxiliary light are displayed. Same as 5. Further, in FIG. 6, the visual target 24S indicating the irradiation range of the AF auxiliary light is displayed smaller than the case of FIG. Note that the through image illustrated in FIG. 2 is also omitted in FIG. 6 in order to make it easier to see the target and the like.

  FIG. 7 is a diagram illustrating an example of a screen displayed on the display device 4 when the zoom position is in the intermediate range between the wide (W) end and the tele (T) end. 7 is the same as FIG. 6 in that the target 21, the target 22, the bar display 23, and the icon 25B are displayed. Further, in FIG. 7, the target 24M indicating the irradiation range of the AF auxiliary light is displayed larger than the case of FIG. Note that the through image illustrated in FIG. 2 is also omitted in FIG.

  FIG. 8 is a diagram illustrating an example of a screen displayed on the display device 4 when the zoom position is at the tele (T) end. 8 is the same as FIGS. 6 and 7 in that the visual target 21, the visual target 22, and the bar display 23 are displayed. Further, in FIG. 8, the target 24L indicating the irradiation range of the AF auxiliary light is displayed larger than the case of FIG. 7, and the target 22B indicating the AF area that is included in the range indicated by the target 24L, and An icon 25 indicating that the AF auxiliary light is turned on is displayed. In FIG. 8, the through image illustrated in FIG. 2 is omitted in order to make it easier to see the target and the like.

  In step S <b> 22, the CPU 11 performs a shooting process and ends the process illustrated in FIG. 3. The shooting process is performed as follows. For example, the focus adjustment by the contrast AF process described above is performed, the subject brightness is acquired based on the latest output value output from the image sensor 2, a known exposure calculation is performed using this brightness, and the exposure calculation result is obtained. The image sensor 2 is caused to perform charge accumulation processing.

According to the first embodiment described above, the following operational effects can be obtained.
(1) Since the AF auxiliary light is emitted (the subject brightness is less than the level necessary for the contrast AF process), the target 24 indicating the irradiation range of the AF auxiliary light is displayed over the through image. It is possible to visually notify the photographer of the irradiation range of the AF auxiliary light on the photographing screen.

(2) Since the size of the visual target 24 is changed according to the zoom position (24S, 24M, 24L), a change in relative irradiation range of the AF auxiliary light accompanying the change in the shooting angle of view is given to the photographer. Visual notification is possible.

(3) When the AF area is within the irradiation range of the AF auxiliary light (that is, inside the target 24), the icon 25 indicating that the AF auxiliary light is turned on or the display mode of the target 22 indicating the AF area is displayed. (22B), it is possible to easily display whether or not the AF area is within the irradiation range of the AF auxiliary light.

(4) By performing the display of (1) to (3) above, the photographer is within the AF auxiliary light irradiation range (that is, the target 24 (24S, 24M, 24L) with the AF auxiliary light turned on. The zoom change operation and the AF area designation operation can be performed so as to designate the AF area at a desired position in ()).

  Instead of the visual target 22 indicating the AF area displayed outside the visual target 24 at the AF auxiliary light emission level, the visual target 22C illustrated in FIG. 9 may be displayed. As described above, if the color, shape, and the like are displayed in a different manner from the visual target 22B indicating the AF area displayed in the visual target 24 at the AF auxiliary light emission level, the display color and shape are not as described above. Also good.

(Second embodiment)
In the first embodiment, the target 24 (24S, 24M, 24L) indicating the irradiation range of the AF auxiliary light is displayed so as to overlap the through image, and the photographer performs at least one of the zoom change operation and the AF area designation operation. As a result, the AF area can be designated within the irradiation range of the AF auxiliary light. In the second embodiment, the electronic camera restricts the designated range of the AF area to the irradiation range of the AF auxiliary light.

  The flow of camera processing performed by the CPU 11 of the electronic camera according to the second embodiment will be described with reference to the flowchart of FIG. Compared with the flowchart of FIG. 3, steps S15B and S16B are added, and steps S17 to S20 are omitted. Therefore, these differences will be mainly described.

  In step S15B of FIG. 10, the CPU 11 limits the specifiable range of the AF area within the irradiation range of the AF auxiliary light, and proceeds to step S16. Thereby, when an operation signal for designating the position of the AF area is input from the operation member 8, the operation signal for designating outside the target 24 (24S, 24M and 24L) indicating the irradiation range of the AF auxiliary light is invalidated. To do.

  In step S <b> 16 </ b> B, the CPU 11 moves the AF area located outside the visual target 24 (24 </ b> S, 24 </ b> M, and 24 </ b> L) indicating the irradiation range of the AF auxiliary light to the target (that is, within the irradiation range of the AF auxiliary light). Move. The position of the AF area after the movement is moved so that the movement amount from the position before the movement becomes the shortest. For example, the AF area positioned at the upper left in the photographing screen before the movement is moved so as to be positioned at the upper left within the irradiation range of the AF auxiliary light after the movement.

  FIG. 11 is a diagram exemplifying a screen displayed on the display device 4 when the zoom position is in the intermediate range between the wide (W) end and the tele (T) end. In FIG. 11, the point 22B, the bar display 23, and the icon 25 are displayed, which is the same as in FIG. 7 or FIG. 8 of the first embodiment. Further, in FIG. 11, the target 24 indicating the AF auxiliary light irradiation range is omitted, and the target 21B indicating the AF area specifiable range is displayed. In the state where the display of FIG. 11 is performed, the operation signal for designating the AF area outside the range indicated by the target 21B is invalidated. Note that the through image illustrated in FIG. 2 is also omitted in FIG. 11 in order to make it easier to see the target and the like.

According to the second embodiment described above, the following operational effects can be obtained.
(1) While the AF auxiliary light is emitted, the specifiable range of the AF area is limited to the AF auxiliary light irradiation range, so that the photographer mistakenly moves the AF auxiliary light out of the AF auxiliary light irradiation range. Specifying an area is prevented.

(2) When the AF area is located outside the target 24 (24S, 24M and 24L) indicating the irradiation range of the AF auxiliary light, it is moved into the target (that is, within the AF auxiliary light irradiation range). As a result, it is not necessary for the photographer to respecify the AF area within the irradiation range of the AF auxiliary light, and an electronic camera that is easy to use can be obtained.

(3) According to the above (1) and (2), the photographer can arbitrarily perform the AF area designation operation within the target 24 (24S, 24M, 24L) indicating the irradiation range of the AF auxiliary light. it can.

  The present invention can be applied not only when the AF auxiliary light is output from the dedicated auxiliary light device 12 but also when the AF auxiliary light is output from a photographing illumination device (flash light emitting device) such as a flashlight. In this case, data indicating a light distribution pattern of light output as AF auxiliary light may be stored in the CPU 11 in advance, and the irradiation range of the AF auxiliary light may be calculated using this data.

  In the above description, an autofocus camera using the contrast detection AF method has been described as an example. However, the present invention can also be applied to a phase difference detection method configured to be able to select an AF area and an external light autofocus camera.

  In the above description, the target or icon is displayed so as to overlap the through image displayed on the display device 4, but the projected image such as the target or icon is synthesized with the subject image observed with the optical viewfinder. It is good also as a structure. For example, when combining an image such as a target or icon with a subject image observed through an eyepiece lens of a single-lens reflex camera, an optical image of the target or icon is generated by a light emitting member such as an LED, and the generated optical image is By using a reflecting member such as a prism, it is overlapped with the subject light beam observed by the optical viewfinder.

  Alternatively, a transmissive liquid crystal display panel is arranged in the optical path of the subject light beam observed by the optical finder, and a target image observed by the optical finder is displayed by displaying a target or icon on the transmissive liquid crystal display panel. Combining targets and icons.

  In this way, the present invention can be applied not only to an electronic camera but also to a silver halide camera if the image such as a visual target or an icon is combined with a subject image observed with an optical viewfinder.

  Correspondence between each component in the claims and each component in the best mode for carrying out the invention will be described. The light emitting means is constituted by the auxiliary light device 12, for example. The composite display means is constituted by, for example, the image processing circuit 3 and the display device 4. The display control means and the restriction means are constituted by the CPU 11, for example. In addition, as long as the characteristic function of this invention is not impaired, each component is not limited to the said structure.

1 is a block diagram of an electronic camera according to a first embodiment of the present invention. It is a figure explaining the example of a display by a display apparatus. It is a flowchart explaining the flow of the camera process performed by CPU. It is a figure explaining the example of a screen displayed on a display apparatus. It is a figure explaining the example of a screen displayed on a display apparatus. It is a figure explaining the relationship between a zoom position and the irradiation range of AF auxiliary light. It is a figure explaining the relationship between a zoom position and the irradiation range of AF auxiliary light. It is a figure explaining the relationship between a zoom position and the irradiation range of AF auxiliary light. It is a figure explaining the example of a screen displayed on a display apparatus. It is a flowchart explaining the flow of the camera process performed in 2nd embodiment. It is a figure explaining the example of a screen displayed on a display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... Zoom lens 1b ... Focus lens 2 ... Image pick-up element 3 ... Image processing circuit 4 ... Display apparatus 7 ... Memory 8 ... Operation member 9 ... Focus control mechanism 10 ... Zoom control mechanism 11 ... CPU
12 ... Auxiliary light devices 21, 22 (22B), 24 (24S, 24M, 24L) ... Target 23 ... Bar display 25 (25B) ... Icon

Claims (6)

In an autofocus camera that acquires focus adjustment information corresponding to the focus area specified at any position in the shooting screen and performs focus adjustment based on the acquired focus adjustment information.
A light emitting means for emitting illumination light toward a partial area in the shooting screen when acquiring the focus adjustment information;
An autofocus camera comprising: composite display means for displaying an illumination range of the light emitting means superimposed on a subject image at least before a photographing instruction. The autofocus camera according to claim 1,
The autofocus camera is an electronic camera equipped with an image sensor,
An autofocus camera, wherein the subject image is a through image displayed on a display device. The autofocus camera according to claim 1,
An autofocus camera, wherein the subject image is an optical image by an optical viewfinder. In the autofocus camera according to any one of claims 1 to 3,
The composite display means further displays the position of the designated focus area on the subject image;
The auto control system further comprises display control means for controlling the composite display means to display the position of the focus area in a different manner depending on whether or not the focus area is within the illumination range of the light emitting means. Focus camera. In the autofocus camera according to any one of claims 1 to 4,
An autofocus camera, further comprising a limiting unit that limits a designated position of the focus area within an illumination range of the light emitting unit. The autofocus camera according to claim 1,
The auto-focus camera characterized in that the composite display means changes the illumination range to be displayed in accordance with the focal length of the photographing lens.

Images