JPH04425A - Camera with automatic focusing device - Google Patents

Abstract

PURPOSE:To easily execute focusing even with a manual operation by displaying an object position in a finder whose photographic distance is detected in a finder when a focusing state is adjusted manually. CONSTITUTION:The line sensor outputs of four focus detection areas are inputted from a focus detection part 8 to a control circuit 7, which calculates a defocusing quantity. At this time, the operation is performed in a mode wherein the focusing of a photographic lens is adjusted manually and a mode wherein the focusing is adjusted automatically. Even when the focusing state is adjusted manually, the LCD in the finder is driven to display the object position whose photographic distance is detected. Therefore, the focusing state becomes distinctive and the focusing is facilitated even in the manual focus mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera, and more particularly to a camera that measures the shooting distance to a subject and automatically adjusts the focus.

[Prior Art] In recent years, there have been an increasing number of cameras that have a so-called autofocus function that automatically adjusts the focus. Such cameras generally have a distance measurement frame displayed in the finder that indicates the distance-measured position of the object, so that the photographer can be informed of which object is in focus.

JP-A-60-64334 and JP-A-60-64
No. 335 discloses a camera that displays a distance measurement frame in a finder until a focus signal is output, and erases the distance measurement frame when the focus is locked at the same time as the focus signal is output.

[Problems to be Solved by the Invention] In the conventional camera as described above, there is no particular problem during autofocus, but it is inconvenient when performing manual focus adjustment, that is, manual focus. This is because if the distance measurement frame is no longer displayed during manual focus, it becomes unclear which subject position is currently in focus, and this causes problems in subsequent focus adjustment operations.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a camera that allows easy focus adjustment even during manual focus.

A camera having an automatic focus adjustment device according to the present invention includes a detection means for detecting a photographing distance to a subject, a display means for displaying the position of the subject to be detected by the detection means in a viewfinder, and a detection output of the detection means. A first mode in which the focus state of the photographic lens is automatically adjusted based on the detection means, and a second mode in which the focus state of the photographic lens is manually adjusted based on information related to the detection output of the detection means. a selection means for selecting the display means; a switching means for switching the display means between activation and deactivation; and when the first mode is selected, the switching means is activated and the second mode is selected. and control means for activating the display means.

[Operation] When the second mode is selected, the position of the subject whose shooting distance has been detected is displayed in the viewfinder.

[Embodiment] FIG. 1 is a block diagram showing the main configuration of a camera according to an embodiment of the present invention.

In the figure, light incident through a photographic lens 9 is reflected by a finder mirror 4, enters a pentaprism 1 via a focusing plate 3 and a transmissive liquid crystal (LCD) 2, and then passes through a finder lens 18. and enters the photographer as an image.

On the other hand, of the light incident on the finder mirror 4, a portion of the light necessary for focus detection passes through the mirror 4 and enters the focus detection section 8 via the submirror 5. Focus detection section 8
is equipped with an optical system necessary for performing focus detection, and includes a sensor, a data output section, etc. The data output from the focus detection section 8 is input to the control circuit 7, and based on the input data, the control circuit 7 outputs data for controlling the focus detection sensor, the sequence, and the LCD drive circuit 6. The LCD drive circuit 6 controls the transmissive liquid crystal 2 based on the control data output from the control circuit 7, and performs various liquid crystal displays.

FIG. 2 is a diagram showing a specific configuration of the focus detection section 8 of FIG. 1.

In the figure, the light reflected from the sub-mirror 5 of FIG. 1 passes through the condenser lens 14 and is formed into four sets of light beams by the re-imaging lens and is imaged onto the COD substrate 11. The autofocus (hereinafter referred to as rAFj) method in this embodiment is a known phase difference detection method.

Here, the aperture mask 13 is set so as to overlap the re-imaging lens 12, and its aperture removes unnecessary light for focus detection coming from the condenser lens 14.

The COD board 11 has focus detection areas a and b, which will be explained later.
, c, and d, a pair of line sensors 11-a, 11-b, 11-c, and 11-d are formed thereon, respectively.

FIG. 3 is a diagram showing the state of a photographing screen of a camera according to an embodiment of the present invention.

In the figure, on the photographing screen 15, distance measurement areas corresponding to each line sensor formed on the COD board 11 of FIG. 2 are shown.

FIG. 4 shows L in the viewfinder according to an embodiment of the present invention.
This shows a state in which all distance measurement frames are displayed on the CD display section. In the figure, the solid line is the liquid crystal display displayed on the LCD display section, and the dotted line corresponds to the ranging area shown in FIG. 3.

Here, the distance measurement frame display 16 is displayed when shooting in a wide AF state covering the entire distance measurement area is being performed. Small ranging frame display 17a~1
7d displays the spot AF state when distance measurement is being performed based on each distance measurement area.

Here, the spot ranging frames are referred to as a central spot frame 17a, an upper spot frame 17b, a left spot frame 17c, and a right spot frame 17d.

FIG. 5 is a diagram showing the configuration of a control section according to an embodiment of the present invention.

In the figure, the control circuit (microcomputer μC) 7
Inputs are made from various switching means. The switch Sar is an area changeover switch, which changes the distance measurement area to a desired area as described later, and when it is turned on, an on signal is input to the boat P1. As will be described later, the switch Sch switches the spot area among the ranging areas, and when it is turned on, an on signal is input to the port P2. AND
An input signal is given to P3 by the circuit 22 only when either of the switches Sar and Sch is turned on, and the AF area routine, which will be described later, is entered.

The switch S1 is a switch that is activated by pressing the release button one step, and when it is turned on, an on signal is input to the port P4 and the AF operation is started. The on/off state of the switch S1 is determined based on the input of the baud P5. Switch Sa, switch sb, and switch Sc are vertical/horizontal detection switches that indicate the direction in which the camera is held at the time of photographing. The shooting posture of the camera is detected by the configuration described later, and each on signal is output as baud) P6 to P
8 to the control circuit 7. Switch SAF/
The FA switch is a switch for switching between autofocus photography and focus aid (FA) photography, which only performs focus detection and does not drive the lens, and when it is turned on, an on signal is input to the boat P9.

- Data is inputted to the force control circuit 7 from the focus detection section 8, and control data for controlling the focus detection section 8 is outputted from the control circuit 7. Further, the control output of the control circuit 7 is transmitted to a transmissive liquid crystal (LCD-C) via a liquid crystal control section (LCD-C) 6.
)2 is controlled.

Furthermore, the control output of the control circuit 7 is output to a lens drive control circuit (LE-C) 20, and the lens drive for autofocus is controlled.

FIG. 6 shows the control flow performed when switch S1 is turned on.

First, when this flow is entered by turning on the switch S1, an interrupt prohibition process is performed in step S1 to prohibit subsequent interrupts from other sources. Next, in step S2, the AF area is displayed. This display is performed by the LCD drive circuit 6 controlling the LCD 2 based on the area (AR) value, and in the initial state of switch-on, normally wide display (ARI) is displayed.

Next, in step S3, AF data, that is, distance measurement data is input from all distance measurement areas. Then, the amount of defocus for each area, that is, area DF (
DFaSDFbSDFc and DFd) are calculated (
Step 84).

Whether or not the AF area is in the wide state in step S5 is determined by the spot flag 5P indicating the spot area display.
It is determined whether TF is "0" or "1". When the AF area is in the wide AF state, a defocus amount DF of 1 is calculated by a predetermined method from the defocus amount of each area obtained in step S4. Note that the spot flag 5PTF is reset (
10″).

On the other hand, when it is not in the wide AF state (NO in step S5)
), the spot area is determined in step S7. When the spot distance measurement area is a, the value DFa of the distance measurement area a is used as the defocus amount in step S8. Similarly, in the case of Eliat 1 area C and area d, the defocus amounts DFb, DFc and D
Fd is used as the defocus amount.

Defocus amount DF determined above in step S12
is less than or equal to a predetermined value. When the defocus amount is less than or equal to a predetermined value, it is determined that the camera is in focus, so that a focus display is performed in step S13. When the defocus amount is larger than a predetermined value, it is determined in step S14 whether the mode is autofocus mode or focus aid mode. When in autofocus mode, the lens is driven to bring it into focus based on the defocus amount DF found in step S15.

On the other hand, in the focus aid mode, the lens is not driven and the process advances to step S16.

In step S16, it is determined whether the switch S1 is off. If the switch S1 is not turned off, the process returns to step S2 and the above-described operation is repeated. On the other hand, when the switch S1 is off, it is assumed that the operation in the switch S1 has ended, and step S1
At step 7, the display on the LCD display section is turned off, and at step 318, interrupt permission is given and the process is stopped.

FIG. 7 is a flowchart showing the specific contents of the AF area routine according to an embodiment of the present invention.

This routine is executed by turning on the switches Sar and Sch from off to on. When this flow is entered, interrupts from other sources are prohibited in step S30 in order to give priority to this flow. And step S3
1, L is determined by the AR value that indicates the display state of the ranging area.
The distance measurement area is displayed on the CD display section. Step S32
It is determined whether the spot flag 5PTF is "1" or not. When this flag is "1", that is, when the spot area is being displayed, it is determined in step S33 whether or not the switch Sar is turned on. Here, the switch Sar is shown in FIG. 5, but in the camera, it is specifically arranged as shown in FIG. 12. That is, the camera body 25
By turning on the switch Sar provided in
The distance measurement area is switched. Further, as shown in FIG. 12, a switch Sch is also provided on the top surface of the camera body 25. and switch Sch
This switch turns on every time you slide it to the right (the position indicated by the broken line), and when you release your hand, it returns to its original position due to the force of the spring, turning the switch off.

When the switch Sar is turned on in step S33, the value of AR is set to ARI in order to display the normal wide display indicated by ARI as shown in FIG. Then, in step S35, the spot flag 5PTF is set to "0".
The process then proceeds to step S53. On the other hand, if the switch Sar is not on in step S33, the spot area display is in progress, so the photographing posture of the camera is detected in step S36. The posture of this camera is specifically shown in FIG. 9 and FIGS. 10A to 10C.

In FIG. 9, the vertical and horizontal detection switches Sa, Sb and S
c has a configuration as shown in the figure. That is, the shaded area is filled with mercury, and as the camera takes a photographic posture, the mercury moves to one of the switches 5a to 8C, causing current to flow through the switch. As a result, the ports (P6 to P6) corresponding to each switch shown in FIG.
The photographing posture is detected when the potential of any one of 8 changes from "H" to "L". Figures 10A to 10C
The figure shows specific photographing postures of the camera.

Next, in step S37, the value ARNEW indicating the currently set distance measurement area is treated as the distance measurement area. However, in the initial state, the distance measurement area value ARNII:W is normally set to the spot value AR4 (see FIG. 11A), which is generally considered to be the most frequently used value.

Next, since the photographing posture has been detected by the vertical/horizontal detection switches 5a-8C shown in FIG. 9, any one of steps 338 to S40 is performed corresponding to each position. For example, if the shooting posture is horizontal, the value of the ranging area AR is set as the initial value in step S38.
If 4 is set, AR4 → AR5 → AR6
The display position of the spot ranging area changes cyclically like →AR7→AR4.

The 11th item shows the specific state of change in the display position.
FIG. 11A to FIG. 11C. Here, FIG. 11A shows the operation in step 338, that is, the photographing posture is in the horizontal position (switch s
b is on), and FIG. 11B shows the process of step S39, that is, the display when the shooting posture is in the vertical position (switch S8 is on), and the 11th CIf
fl indicates the process of step S40, that is, the display change state when the shooting posture is vertical (switch S is on).

Then, in step S41, any A indicating the distance measurement area is selected.
The R value is used as the ranging area AR, and step S
At 42, the ranging area AR is set position ARNI! Used for W. Then, the process advances to step S53.

On the other hand, the spot flag 5PTF is "1" in step S32.
If not, that is, if no spot display is attached, it is determined in step S43 whether or not the area changeover switch Sar is on.

If this switch is not turned on, step S47
Then, it is determined whether the ranging area value AR is a spot display, that is, AR2. When the spot display is selected, the spot flag 5PTF is set to "1" in step 348, and the process returns to step S36, where the above-described spot display position changing process is performed by detecting the photographing posture. If the ranging area value AR is not AR2, step S
Proceed to step 53.

When the area selection switch Sar is on in step S43, the autofocus mode is selected in step S44.
It is determined whether the mode is focus aid mode. In the focus aid mode, if the ranging area value is AR2 in step S46, the ranging area value is AR2.
When the distance measurement area value is ARI, it is set as AR2, and when the distance measurement area value is AR3, it is set as the distance measurement area value ARI.

When in autofocus mode, step S45
Then, the display change cycle shown in FIG. 8 is performed. That is, if the current distance measurement area display is ARI indicating normal wide display, the display is sequentially changed in the order of ARI→AR2→AR3→ARI each time the switch Sar is turned on.

Next, in step S49, it is determined whether the ranging area value AR is 2 or not. When the ranging area value is AR2,
In step S50, the spot flag 5PTF is set to "1", and in step S51, the ranging area value ARNEW of the current spot display is input as the ranging area value AR. On the other hand, A
If it is not R2, set the ranging area value AR to ARl or A.
R3 is input, and in step S53, a display indicating the distance measurement area is made based on the distance measurement area value AR. Step S
54 and step S55 until the switch Sar and the switch Sch are turned off, and then the interrupt is permitted in step S56. Then, in step S57, the timer is reset to start counting, and in step 858, 5 seconds have elapsed, and in step S59, the liquid crystal display on the LCD is turned off, and this flow is stopped.

[Effect of the invention] When the second mode is selected, the position of the subject whose shooting distance is detected is displayed in the viewfinder.
The position of the subject in focus becomes clear, improving usability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the main parts of a camera according to an embodiment of the present invention, FIG. 2 is a diagram showing the specific configuration of the focus detection section in FIG. 1, and FIG. FIG. 4 is a diagram showing the arrangement of the distance area, FIG. 4 is a diagram showing the positional relationship between the arrangement of the CCD board in FIG. 2 corresponding to the distance measurement area in FIG. 3 and the distance measurement frame, and FIG. A block diagram of the control unit according to the embodiment, FIG. 6 is a flowchart showing the control executed when the switch S1 in FIG. 5 is turned on, and FIG. 7 is a diagram showing either the switch Sar or the switch Sch in FIG. 5. FIG. 8 is a flowchart showing the control executed when the switch Sar in FIG. 5 is turned on. FIG. Vertical and horizontal switches Sa, Sb and S in the figure
10A to 10C are diagrams showing the photographing posture of the camera corresponding to the vertical and horizontal switches 5a to 8c,
Fig. 11A is a diagram showing the curved display of the ranging frame in the finder when the vertical/horizontal switch sb in Fig. 5 is turned on, and Fig. 11B is a view showing the viewfinder when the vertical/horizontal switch Sa in Fig. 5 is turned on. Figure 11C is a diagram showing changes in the display of the distance measurement frame in the finder when the vertical/horizontal switch Sc in Figure 5 is turned on; FIG. 3 is a diagram showing a specific arrangement of the changeover switch Sar and the spot changeover switch Sch shown in the figure on the camera body. In the figure, 2 is an LCD display section, 6 is an LCD drive circuit,
7 is a control circuit, 8 is a focus detection unit, 18 is a finder lens, 11 is a CCD board, 12 is a reimaging lens, 13 is an aperture mask, 14 is a condenser lens, 15 is a shooting screen, and 16 is a measurement device in wide display. Distance frame, 17a is a ranging frame with center spot display, 17b is a frame with upper spot display, 17c is a frame with left spot display, 1
7d is a right spot display frame, 20 is a lens drive circuit, Sar is a changeover switch, and Sch is a spot display changeover switch. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure Figure Figure Figure Figure 10A Figure Ta τ side SW: sb left no. 108! 11 Tama Yoko SW: Sa 7th 10C51! Unbalanced T horizontal SW: Se large Figure 11A

Claims (1)

[Scope of Claims] Detecting means for detecting a photographing distance to a subject; display means for displaying the position of the subject to be detected by the detecting means in a viewfinder; a first mode in which the focus state of the photographic lens is automatically adjusted; and a second mode in which the focus state of the photographic lens is manually adjusted based on information related to the detection output of the detection means. means for activating or deactivating the display means; when the first mode is selected, the switching means is activated and when the second mode is selected; , a control means for activating the display means, and a camera having an automatic focusing device.