JPH049019A - Camera provided with automatic focus detecting device - Google Patents

Abstract

PURPOSE:To reduce the possibility of missing of a shutter chance by controlling the selecting order of plural range-finding areas by a selection means so that the area selected by the photographer before photographing is performed this time is prioritized. CONSTITUTION:This camera includes the selection means 51 for selecting the optional range-finding area out of the plural range-finding areas, and a selection means control means 52 for controlling the selecting order of the plural range- finding areas by the means 51 so that the area selected by the photographer before photographing is performed this time is prioritized. Therefore, when the photographer selects the desired range-finding area by using the selection means 51, the means 52 controls the selection means so that the selected range- finding area may be automatically selected when next photographing is performed. As a result, a time for selecting the range-finding area is shortened. Thus, the possibility of missing the shutter chance is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application] The present invention relates to a camera equipped with an automatic focus detection device, and more particularly to a camera equipped with an automatic focus detection device having a plurality of ranging areas.

[Prior Art 1] A camera with an automatic focus detection device which is of interest to the present invention is disclosed in, for example, Japanese Patent Laid-Open No. 1-230012.

According to the camera disclosed in the publication, the camera with an automatic focus detection device has two ranging areas, wide and spot, and the photographer can specify either of the ranging areas, and The area is displayed in the camera. Further, for example, according to Japanese Patent Application Laid-Open No. 1-198715, in a camera having a plurality of distance measurement areas, the distance measurement areas are set and manually stored. Then, that distance measurement area is set as the next distance measurement position after photographing is completed.

[Problems to be Solved by the Invention] A conventional camera with an automatic focus detection device was configured as described above. In the camera disclosed in Japanese Patent Application Laid-Open No. 1-230012, it is necessary to select a distance measurement area before starting the photographing operation every time a photograph is taken. Therefore, it takes time to select an area during photographing, and there is a risk that the photographer may miss a photo opportunity.

According to the camera disclosed in Japanese Unexamined Patent Publication No. 1-198715, in order to set the next distance measurement area before photographing, the photographer must manually store it in the camera. Therefore, during actual photographing, it takes time to select the distance measurement area, and as mentioned above, there is a risk that the photographer may miss a photo opportunity.

This invention was made to solve the above-mentioned problems, and aims to reduce the possibility that a photographer will miss a photo opportunity in a camera equipped with an automatic focus detection device that has multiple distance measurement areas. .

[Means for Solving the Problems] A camera with an automatic focus detection device according to the present invention has a configuration as shown in FIG. 1 in order to achieve the above object. That is, the camera with an automatic focus detection device having a plurality of distance measurement areas according to the present invention includes selection means 51 for selecting an arbitrary distance measurement area from among the plurality of distance measurement areas, and the photographer can select an arbitrary distance measurement area from among the plurality of distance measurement areas. 51 to select a desired distance measurement area according to the subject, and control the selection order of the plurality of distance measurement areas by the selection means 51 so that priority is given to the area selected by the photographer before the current shooting. means control means 52.

However, FIG. 1 is a block diagram showing the configuration of the present invention in functional blocks, and in the embodiments described later, the main part of the above configuration is realized by a microcomputer program.

In this invention, when the photographer selects a desired distance measurement area using the selection means 51, the selection means control means 52 controls the selection means so that the selected distance measurement area is automatically selected for the next photographing. As a result, the time required to select a ranging area is reduced.

“Embodiments of the invention” Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the main parts of the invention. Second
Referring to the figure, the camera with an automatic focus detection device according to the present invention includes a photographic lens 21 for inputting light from a subject into the camera body, and a viewfinder for transmitting the incident light from the photographic lens 21 to a finder 9. a half mirror 4 for use with a finder, a pentaprism 1, and a focus detection unit 8 provided at the rear of the half mirror 4 for a finder for automatic focus detection.
and a sub-mirror 5 for transmitting a subject image to.

Below the pentaprism 1 is a transmissive liquid crystal display (hereinafter referred to as LCD).
) 2 and a focus plate 3 are provided. LCD2
is controlled by a control circuit 7 via an LCD drive circuit 6. The control circuit 7 also controls the focus detection section 8.

FIG. 3 is a diagram showing details of the focus detection section 8.

Referring to FIG. 3, focus detection section 8 performs automatic focus adjustment using a phase difference detection method. Referring to FIG. 3, CCD board 1
1, there are four focus detection areas aSbSc that will be explained later.
, d are provided with a pair of line sensors ~■, respectively. In front of the CCD board 11, a re-imaging lens 12 is provided for guiding the light of the object to the line sensor 1 on the CCD board 11. The re-imaging lens 12 is provided with an aperture mask 13 for removing unnecessary light. A condenser lens 14 is provided in front of the re-imaging lens 12 in order to guide the necessary light from the object to the CCD substrate 11 and the re-imaging lens 12. In FIG. 3, a film equivalent surface 20 is shown in front of the condenser lens 14 by a two-dot chain line.

FIG. 4 is a diagram showing four focus detection areas a to d on the photographic screen corresponding to the four line sensors to (2) shown on the CCD board 11 of FIG. 3. FIG. As shown in Figure 4,
Focus detection is performed at four positions on the photographic screen.

Figure 5 shows the display section that can be checked on the camera's finder 9 and the focus detection areas a-d on the shooting screen shown in Figure 4.
FIG. Referring to FIG. 5, ARI to AR6 indicated by solid lines are displayed on the LCD 2.
This is the CD display section.

The area indicated by the dotted line is the focus detection area a shown in Figure 4.
-corresponds to d. As shown in FIG. 5, in the camera according to the present invention, the distance measurement areas where focus detection is actually performed are the four areas a to d indicated by dotted lines, or the focus detection during shooting is as shown in FIG. Focus detection area AR1- indicated by a solid line
This is carried out in six areas represented by ~AR6. That is, focus detection areas AR2, AR4 to AR6 correspond to focus detection areas a to d, respectively, but focus detection area AR1 performs automatic focus detection based on all the focus detection information of focus detection areas a to d. Let's do it. Also, the focus detection area,
In step R3, focus detection is performed using a portion of the focus detection area a, as will be explained in detail later.

FIG. 6 shows the CCD substrate 11 shown in FIG. It is a diagram showing details of the above four line sensors I to ■.

Each line sensor includes a reference part B and a reference part R corresponding thereto. By smoothing the image of the reference portion B relative to the image of the reference portion R, the reference portion B,! :Detect the correlation of the image with the reference portion R, and perform focus detection based on the result.

The reference section indicated by the sensor IIB is divided into three sections A, B, and C as shown in the figure. The parts of the reference part IIB of the second island are not themselves compared all at once with the data of the corresponding reference part IIR;
The focus of each area is detected by comparing each block of A, B, and C with the reference portion ①R.

The area indicated by the second island ■ is A-C as shown.
The reason for dividing it into three areas is as follows. The area represented by the second island
The area it covers is wider than the Island and the 4th Island. As a result, subjects existing in far and near areas may be mixed together in one area. Then, when a correlation is taken for focusing between the reference part and the reference part R, the defocus amounts of both near and far objects are added to the correlation value as an error amount, which causes the problem that focus detection becomes difficult. be. Therefore, in the present invention, the second island is divided into three areas so that automatic focus detection can be easily performed.

When focus detection area AR3 in FIG. 5 is selected, focus detection is performed using area C shown in FIG.

. When focus detection is performed using focus detection area AR2, focus detection is performed using A to C shown in FIG. 6, and when focus detection is performed using focus detection area AR1, Focus detection is performed using the focus detection areas between the first island to the fourth island (1) to (4) shown in FIG.

Next, the configuration and operation of the control section of the camera according to the present invention will be explained.

FIG. 7 is a block diagram showing the main parts of the control section of the camera according to the present invention. Referring to FIG. 7, the control unit of the camera according to the present invention includes a control circuit (hereinafter abbreviated as a microcomputer) 31 which is the central part of the control unit, and an automatic focus circuit connected to the microcomputer 31 to perform an automatic focus detection operation. a detection circuit 32, a liquid crystal control circuit 33 for controlling the LCD 2 that displays the display section for indicating the focus detection area shown in FIG. 5, and a lens drive control circuit 34 for driving the photographing lens 21; A lens circuit 35 for inputting lens information from the photographing lens 21 is connected.

The microcomputer 31 includes a mode switch Smod for switching the shooting mode, which will be explained later, a spot switch Ssp for switching between multiple distance measurement areas, and an automatic focus switch that is turned ON when the first stage of the release button (not shown) is turned on. A detection start switch Sl7 and a main switch Sm for driving the camera body are provided.

Next, the operation of the camera according to the present invention will be explained with reference to FIG. When the main switch Sm is turned on, flowchart 1 in FIG. 8 starts. At the start, AR3 is set to the variable 5PAR, which represents the spot area that becomes the focus detection area based on the initial value, and King is set to the variable AR, which represents the focus detection area, and the flag is reset.
Assume that it is sorted.

First, in step #11, an area for outputting a signal serving as a reference for automatic focus detection is displayed.

The focus detection area where this automatic focus detection is performed is indicated by one of AR↑ to AR6 shown in FIG.

In this case, the flag DI for not displaying the focus detection area is set.
If SPF is 1, the area where automatic focus detection is performed will not be displayed.

Next, it is determined in #13 whether the mode switch Smod has been switched from OFF to ON. When it is determined in #13 that the mode switch Smod has been turned on from OFF, it is determined in #15 whether the spot mode flag SPMF is set. If it is determined in #15 that the spot mode flag SPMF is not set, the display flag is replaced in #17, and if it is determined in #15 that the spot mode flag is set, the display flag is replaced in #27. The spot mode flag is reset and the flag DI SPF is set at #29, both at #1.
9, the spot flag SPF is reset as an initial setting. Next, lens data is input from the lens circuit 35 shown in FIG. 7 at #21. #23 to below depending on the F value that indicates the brightness of the lens included in the lens data.
In step 37, the focus detection area AR used in the lens is automatically determined. The details will be explained in detail below.

When performing focus detection in step #23, it is determined whether AFAVo, which is the maximum open F value, is larger than a predetermined value (6.7 in this embodiment). When it is determined in #23 that AFAVo is larger than the predetermined value, ARI is set as the variable AR indicating the focus detection area. #31
And AFAV.

is larger than a second predetermined value that is smaller than the predetermined value. In this embodiment, it is determined whether the photographing lens 21 is a reflective telephoto lens. This is because reflective telephoto lenses generally have a small maximum open F value. If it is determined in #31 that the lens is darker than the predetermined second value, the variable A representing the focus detection area is set in #37.
AR3 is set in R, otherwise A is set in AR.
R2 is set, and in either case, the spot flag is set at #35.

In this way, the focus detection area is automatically determined based on the data of the photographic lens.

Next, switching of the spot for focus detection will be explained.

In #39 it is determined whether the mode switch Smod is ON, in #41 it is determined whether the spot mode flag SPMF is set, and in #43 the spot switch Ssp is determined.
It is determined whether the switch has changed from OFF to ON. Next, when it is determined in #45 that the spot flag SPF is not set, in #47, each press of the spot switch Ssp changes the focus detection area to AR3, AR4, AR, 5, A.
It switches in the order of R6. Then, in #49, this switched focus detection area is set to a variable AR representing the focus detection area. When it is determined that the spot flag is set in #45, since the photographing lens 21 is a dark lens, the variable AR indicating the focus detection area is set to AR3 indicating the smallest focus detection area, and any In this case, the variable AR indicating the focus detection area is also set in #51, which is set to the variable 5PAR indicating the spot area. If the spot switch is not pressed in #43, the program returns to #11 to display the automatic focus detection area.

If it is determined in #39 that the mode switch is not ON, the program advances to #55 and the spot switch is turned ON.
It is determined whether the switch has been made from FF to ON. If it is determined that the switching has occurred, the spot mode flag is set in #57, and it is determined in #59 whether the spot flag is set. If the spot flag is set here, the variable AR indicating the focus detection area is set to AR3, otherwise the variable 5PAR indicating the previously set focus detection area is set to AR. Flag DISP to display focus detection area in #63
F is set. If it is determined in #55 that the spot switch has not been pressed, the program continues #
11 Return to automatic focus detection area display 6 Next, referring to FIG. 9, the operation when the automatic focus detection start switch S1 is turned on will be described with reference to FIG.

When the automatic focus detection start switch S1 is turned on, #
Initial setting is performed in step 70, and variable A indicating the focus detection area
The initial value of R and ARl- are set with (-, and each flag is reset. The area where automatic focus detection is performed, that is, the focus detection area is shown in #71. This is done by controlling the LCD 2 via the LDC control circuit 33 according to the value of the variable AR indicating the area and the flag DISPF indicating the focus detection area.Therefore, the flag DiSPF indicating the focus detection area is set. When there is no focus detection area, the focus detection area is not displayed.

Next, automatic focus detection data is input in #73, and the amount of defocus for each focus detection area is determined in #75. Here, DFA-DFCXDF, 4 to DF6 correspond to A-C and AR4 to AR6 of the focus detection area nB, respectively.

In #77, the defocus amount for each focus detection area is calculated based on the defocus amount for each focus detection area, and #
At 79, it is determined whether the focus detection area is an ARI. If it is determined that the focus detection area is ARI, the defocus amount DF is determined based on DF], DF4, DF5, and DF6. Focus detection area is AR in #79
When it is determined that it is not I, it is determined in #85 whether the focus detection area is AR2. Here, the focus detection area is A
If it is determined that it is R2, the defocus amount DF is set in #97.
The DPI obtained earlier is set, and AR2 is set in #85.
If it is determined that it is not, the focus detection area is determined in #87, and the defocus amount DF is determined based on the defocus amount obtained in that focus detection area according to each value, and each value is determined. The photographing lens 21 is driven to the in-focus position in response to the following. Next, in #99, it is determined whether or not the automatic focus detection start switch S1 is OFF. If it is determined that it is OFF, the display of the frame indicating the focus detection area is turned off in #101, and the program returns. If it is determined in #99 that the automatic focus detection start switch S1 is not turned off, the program returns to #71.

Next, with reference to FIGS. 10 and 11, switch Smod and spot switch Sp are turned OFF and OFF.
This section explains mode switching and spot switching using N.

First, mode switching will be explained with reference to FIG. The camera according to the present invention has two modes: a mode in which a frame indicating the focus detection area is displayed and a mode in which it is not displayed. Flag DISPF
When the flag DISPF is set, a frame is displayed, and when the flag DISPF is not set, a frameless mode is entered in which no frame is displayed. As shown in steps #1-3 to #17 in Fig. 8, the mode switch Smod is changed from OFF to ON, and display/non-display of the frame in the focus detection area can be selected only when the frame is not in the spot mode. . This state is shown in FIG. FIG. 10 is a diagram showing the field of view in the finder 19. If the flag DISPF is set, a frame indicating the focus detection area is displayed as shown in the upper row, and the flag DISPF is set.
When F is not set, the frame indicating the pointless detection area is not displayed as shown in the lower row.

There are three types of frames for displaying the focus detection area; as shown in steps #21 to #35 in FIG. This is because the area is determined.

Next, referring to FIG. 11, a description will be given of a spot mode for switching the spot area in which focus detection is performed. In the spot mode, the spot in the focus detection area where focus detection is performed is switched as shown in FIG. 11 by switching the spot switch Ssp. Each spot area where focus detection is performed is focus detection area AR3 to AR6.
, and this position was explained earlier in Figure 5.
Corresponds to the ゜ position.

To set the Naori Mera to spot mode, as shown in #39 to #47 in the flowchart of Fig. 8, mode switch Smod is ON and spot switch Ss is turned on.
Only when p is switched from OFF to ON. That is, when the spot mode is set, there is no frameless display.

Referring to #41 to #51 and #11 to #37 in Fig. 8,
When the camera is in spot mode, the mode switch is set to O.
When switched from FF to ON, the four focus detection areas AR3 to AR6 shown in FIG. 11 are thereby switched to the focus detection areas ARI to AR3 shown in FIG. 10.

However, even in this case, it does not become frameless.

As described above, in the present invention, the spot area for focus detection cannot be selected unless the mode switch and the spot switch are turned on. As a result, malfunctions can be prevented.

Furthermore, the spot area can be switched by using the spot switch Ss.
You can easily switch by simply pressing p. moreover,
You can quickly switch from spot mode to wide mode by simply pressing the mode switch once.

[Effects of the Invention] As described above, according to the present invention, in a camera having a plurality of rear rangefinders, wide automatic focus detection is performed in which automatic focus detection is performed using all the rear rangefinders, and an arbitrary rangefinding area can be selected. In a camera having two modes of spot automatic focus detection in which automatic focus detection is performed, the distance measurement area used last time is automatically set as the distance measurement area in which spot automatic focus detection is performed. Therefore, since the frequently used AF area is selected in advance depending on the photographer, the time required to select the AF area before shooting can be shortened, and as a result, the camera with multiple AF areas has a good chance of taking a photo. It is possible to obtain the effect of not allowing any of the substances to escape.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of a camera with an automatic focus detection device according to the present invention, FIG. 2 is a schematic diagram showing the optical system of the camera to which this invention is applied, and FIG. FIG. 4 is a schematic diagram showing a focus detection section of a camera to which the invention is applied; FIG. 4 is a diagram showing a focus detection area on the photographing screen of the camera to which the invention is applied; FIG. FIG. 6 is a diagram showing the details of the line sensor on the COD board, and FIG. 7 is a diagram showing the positional relationship between the LCD display section of the camera and the ranging area shown in FIG. is a block diagram of a camera control unit to which
8 and 9 are flowcharts showing the operation of the camera to which the present invention is applied, and FIGS.
The figure shows focus detection areas on the finder that are switched by pressing the mode switch and spot switch. 1 is a pentaprism, 2 is a transmissive liquid crystal, 3 is a focus plate, 4
1 is a total reflection mirror for the finder, 5 is a submirror, 19 is a finder, 21 is a photographic lens, 31 is a control circuit, 32
33 is an automatic focus detection circuit, 33 is a liquid crystal control circuit, 34 is a lens drive control circuit, 35 is a lens circuit, 51 is a selection means,
52 is a selection means control means. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. island map

Claims (1)

[Scope of Claims] A camera with an automatic focus detection device having a plurality of distance measurement areas, comprising: selection means for selecting an arbitrary distance measurement area from the plurality of distance measurement areas; A desired distance measurement area is selected using a selection means and a photograph is taken, and the order in which the plurality of distance measurement areas are selected by the selection means is given priority to the area selected by the photographer before the current photographing. and a selection control means for controlling the camera.