JPH07199043A - Focus adjustment device - Google Patents

Abstract

(57) [Summary] [Purpose] Without increasing cost and space,
Enables multi-point focus detection. When a focus detection point that does not correspond to the focus detection means 16 is selected, an image shift operation is performed by the shift means 2 prior to the start of the focus detection operation, and the focus detection point position of the focus detection means is selected. The images corresponding to the focus detection points are made to substantially coincide with each other, the focus detection operation is performed, and the control means 10 and 11 for adjusting the focus of the imaging optical system 4 based on the obtained focus state signal are provided, and an existing image is provided. Focusing fluctuations caused by image shifts in the shift means used for shake correction are practically negligible, and attention is paid to the fact that the shift operation can be performed at a sufficiently high speed, and the position of the optical device equipped with the device is moved. Without performing the shift operation of the image by the shift means, the focus detection operation is performed by causing the image corresponding to the selected focus detection point to substantially coincide with the focus detection point position of the focus detection means. It

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a TTL focus adjusting device such as a single-lens reflex camera, and more particularly to a focus adjusting device having a plurality of focus detection points and capable of so-called multi-point focus detection.

[0002]

2. Description of the Related Art A conventional multi-point focus detection device is disclosed in Japanese Patent Laid-Open No. 3-2.
Like the TTL method described in No. 30140, it has a plurality of points or areas (= focus areas, hereinafter abbreviated as FA) for focus detection, and the F
In order to perform focus detection on all the FAs or the subject corresponding to the selected FA by superimposing A, the number of optical systems and sensor pairs (groups) corresponding to all FAs are It is generally provided.

Also, in selecting one of the FAs,
There is also an example using the line-of-sight detection device described in JP-A-2-206425 and the like.

Then, the above multi-point focus detection device, and
As a single-lens reflex camera equipped with both the line-of-sight detection device, "Canon EOS5 (trade name)" has already been commercialized by the applicant of the present application and is on the market.

On the other hand, as a lens system, an anti-vibration lens having a shift optical system using a variable apex prism (Variabie Angle Prizm = VAP) or the like is disclosed in Japanese Patent Application Laid-Open No. 4-1437.
No. 38, etc., and is commercialized.

These shift optical systems are sufficiently corrected for aberrations in practical use, and the focus fluctuation due to the shift operation is sufficiently eliminated. In addition, because of the camera shake correction, it is possible to perform high-speed image shake correction capable of handling vibrations of at least several Hz to several tens Hz.

[0007]

However, in the above-mentioned conventional example, when a camera / lens system capable of driving the correction optical system and detecting multi-point focus is constructed, a new effect is obtained by the mutual function combination by the cooperation thereof. Has not been found,
The hardware cost for each function was more significant than the function.

In particular, when a so-called phase difference detection method based on secondary imaging is used for the AF method in order to have a multi-point FA, at least one pair of line sensor and secondary imaging for one FA. A lens, a field mask, etc. are required, and as the number of points increases, the size of the sensor chip must be increased, and the dimensions and layout space of the lenses and mirrors for guiding the optical path to the AF system must be increased.

Further, when an FA that is two-dimensionally arranged vertically and horizontally in the viewfinder field is to be constructed, the expansion of the space increases the layout difficulty, and the size of the camera is easily increased, and the cost is reduced. However, increasing FA was not easy.

(Object of the Invention) An object of the present invention is to provide a focus adjusting device capable of performing multipoint focus detection without increasing cost and space.

[0011]

According to the present invention, there are provided selection means for selectively designating focus detection points at a plurality of positions in a finder, and a number of focus detection points smaller than the number of selectable focus detection points at the plurality of positions. When a focus detection point that does not correspond to the focus detection means is selected by the focus detection means having the, and the selection means, the shift operation of the image is performed by the shift means prior to the start of the focus detection operation. Provided is a control means for causing the image corresponding to the selected focus detection point to substantially coincide with the focus detection point position, performing the focus detection operation, and adjusting the focus of the imaging optical system based on the obtained focus state signal. Focusing on the fact that the focus fluctuation due to the image shift by the shift means used for the existing image blur correction is practically negligible, and the shift operation can be performed at a sufficiently high speed, the device is mounted. The image shift operation is performed by the shift device without moving the position of the optical device, and the image corresponding to the selected focus detection point is substantially aligned with the focus detection point position of the focus detection device to perform the focus detection operation. I am trying.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a block diagram showing the configuration of the essential parts of a single-lens reflex camera equipped with a focus adjusting device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a lens unit having a zoom function, which is a shift optical system 2 using a variable apex angle prism capable of shifting an image in an arbitrary direction by biaxial control, and a zoom system 3 for zooming. , A focus system 4 for focus adjustment, and drive systems 5, 6 and 7 for driving these, including position detection encoders, actuators, and drive circuits. Reference numeral 8 denotes a shake sensor that detects vibration such as camera shake. Reference numeral 9 denotes a memory, which stores the lens focus sensitivity, lens shift information, and the like as lens-specific data using the focal length as a parameter.

These elements are interfaces (not shown) (noted below as I / 0) to the lens microprocessor 10.
Connected and controlled via.

The above is the outline of the lens side, and the iris diaphragm and the like as the light quantity adjusting means not directly related to the contents of the present invention are omitted.

Next, an outline of the camera body side will be described.

Reference numeral 17 denotes a quick return mirror having a half mirror portion, which is arranged at a position of 45 ° as shown in the drawing except during photographing, and splits the light incident through the lens portion 1 into a finder light flux and a focus detection light flux. To do. Reference numeral 18 denotes a sub-mirror that guides the light flux that has passed through the quick return mirror 17 to a multi-point focus detection system 16 arranged at the lower part of the camera. The light flux that is guided to the multi-point focus detection system 16 is a known pupil division secondary combination not shown. An image is formed on a focus detection sensor such as a pair of line sensors by the image means, and a focus state signal is generated based on the phase difference between the outputs of the pair of focus detection sensors.

A focus 20 is arranged at a position not equivalent to the image plane 19 and the light beam reflected by the quick return mirror 17 forms an image here. A superimpose display system 33 having a transmissive liquid crystal display section is arranged adjacent to the focusing plate 20, and a visual field and a superimpose display are provided to an eye 23 of an observer via a pentaprism 21 and an eyepiece lens 22. To be done. Reference numeral 34 denotes a photometric system, and the focusing plate 20 transmits the image-formed light flux, but since it has diffusivity, a light flux outside the optical axis enters it through the pentaprism 21 to generate a photometric signal. It

The eyepiece lens 22 is formed by laminating cut lenses, and a dichroic mirror 22-1 that transmits visible light and reflects infrared light is formed on the cut surface, and is observed by irradiation of an infrared light source 24. The reflected light from the human eye 23 is guided to a known line-of-sight detection system 25, and an image is formed on the infrared area sensor by an imaging lens (not shown). The line-of-sight detection system 25 performs signal processing on the output of the infrared area sensor. Then, the gazing point of the observer is detected. Since a specific detection algorithm and the like are known, description thereof will be omitted.

The quick return mirror 17 described above is used.
At the time of shooting, the image of the subject is formed on the image forming surface (film surface) 19 because it retracts from the shooting optical path together with the sub-mirror 18.

Reference numeral 12 is a focus detection point selection mode switching means (slide switch as will be described later in this embodiment) for selecting either the line-of-sight input mode or the manual selection mode, and 13 is a switch AFSW for starting the focus adjustment operation. Like many cameras, it is a switch that turns on in conjunction with the first stroke of the release button), 14 is a memory, and 15 is a focus detection point selection switch.

Reference numeral 11 denotes a camera microprocessor which is connected to the above-mentioned components via an I / 0 (not shown), and is adapted to mutually communicate with the lens microprocessor 10 described above.

FIG. 2 is a diagram showing an upper surface operation section and switches of the single-lens reflex camera shown in FIG.

Reference numeral 26 is a camera body, 27 is a release button, 28-1 to 28-4 are focus detection point selection buttons (see FIG. 1).
Corresponding to the focus detection point selection switch 15). Reference numeral 29 is a focus detection point selection mode switching knob (corresponding to the focus detection point selection mode switching means 12 in FIG. 1), and 30 is capable of selecting either the manual selection mode mark 30 or the line-of-sight input mode mark 31. . Reference numeral 32 is a viewfinder eyepiece frame.

FIG. 3A is a diagram showing the entire contents displayed on the superimpose display system 33 of FIG.

In the field of view frame 301, “3 rows × 9 columns”, a total of 2
A seven-point FA (focus area) display unit, a focus detection impossible (AFNG) display unit 302, a manual selection mode display unit 303, and a line-of-sight input mode display unit 304 are arranged,
Each of the "27 + 3 = 30" segments has a structure of a known transmissive liquid crystal display that is independent and capable of blinking display.

FIG. 3 (b) shows only three FAs whose focus can be detected by the focus detection system 16 shown in FIG. 1, and the FA arrangement in the x direction in FIG. 3 (a) is equally pitched at L1. In this case, the peripheral focus detection points of FA-A and FA-C are arranged at a pitch of 2L1 from the center of FA-B corresponding to the center of the optical axis. It has the same configuration as the three-point focus detection AF single-lens reflex camera that has already been commercialized. still,
In the figure, A, B, and C are symbols for this description and are not actually displayed.

Next, the actual focus adjusting operation will be described with reference to the flow charts of FIGS. When the power is turned on, the operation from step S1 is started. [Step S1] When the power is turned on, a power-up clear circuit (not shown) operates to initialize the parameters of the microprocessors 10 and 11 on the lens side and the camera body side. [Step S2] The lens shift information stored in the memory 9 on the lens side is loaded into the camera microprocessor 11.

Here, the lens shift information includes normal A
In addition to the information possessed by the F system interchangeable lens, it has information as to whether or not the lens has a shift function as the lens ID information. Also, the shiftable direction and the possible displacement amount are included as lens status information. Since the latter uses a zoom optical system in the present embodiment, a plurality of values as the shiftable amount Smax at each zoom position are communicated and fetched at any time.

When a non-shiftable lens is attached according to the lens ID information, the AF system operates as a general AF system, but since it deviates from the contents of the present case, the details are omitted and the shiftable lens is attached. Only if
The following is added. When the non-shiftable lens is attached, the menu display state E shown in FIG. 8 is displayed on the finder, and the conventional three-point focus detection is performed only in the real focus detection area. In the mode display, either the manual selection mode display unit 303 or the line-of-sight input mode display unit 304 is displayed depending on the selected mode. [Step S3] A focus detection point at which FA can be selected for both lens shift information is determined. The information related to the shift described above is the real focus detection area (F
(A-A, FA-B, FA-C) and the pitches L1 and L3 between the displayable focus detection areas and the areas where the actual focus detection points exist within the range of the shiftable amount are defined as selectable focus detection points. judge. [Step S4] Focus detection point selection mode switching means 12
Detect the state of. [Step S5] In step S4, if the line-of-sight input mode is selected, the process proceeds to step S10, and if the manual selection mode is selected, the process proceeds to step S6.

Here, assuming that the line-of-sight input mode is selected, the operation after step S6 will be described first. [Step S6] By the determination in step S3,
Any one of the menu (focus detectable area) display states A to E, a part of which is illustrated in FIG. 8, and the manual selection mode display portion mark 303 are displayed together in the viewfinder.

The shiftable amount in the horizontal and vertical directions is SmaxX,
When SmaxY is set, the relationship with the menu display example shown in FIG. 8 is as follows.

[0034] [Step S7] The focus detection point selection switch 15 is detected, and when the switch is ON, an adjacent FA in a predetermined direction is set as a focus detection point and blinks. The initial position is FA-B which is the central FA.

The focus detection point selection switch 15 has a timer processing function such as OFF detection and repeat similar to the known keyboard switch for electronic equipment. [Step S9] The state of the switch AFSW13 is detected, and if ON, the process proceeds to step S14, and if OFF, the process returns to step 4 via.

If the manual selection mode is selected in step S5, step S1 is executed as described above.
The operation from 0 is advanced. [Step S10] The line-of-sight input mode display unit 304 and the menu display illustrated in FIG. 8 are displayed together in the finder. [Step S11] The state of the switch AFSW13 is detected, and if ON, the process proceeds to step S12, and if OFF, the process returns to step 4 via. [Step S12] The visual axis detection system 25 is activated to detect the visual axis position and determine the nearest FA. [Step S13] The FA superimposed and displayed in the finder is blinked based on the result of the sight line input detection.

In step S9, the switch AFSW is set.
When it is determined that 13 is ON, or after the FA selected by the line-of-sight input is displayed in blinking in step S13, the process proceeds to step S14. [Step S14] The designated FA manually selected or the line-of-sight input is the real focus detection areas FA-A, FA-B,
It is determined whether any of FA-C matches, and if there is a match, the process proceeds to step S15 of FIG. 5, and the same focus detection flow as in the related art is started. On the other hand, if they do not match, the process proceeds to step S22 of FIG. 6 to start the shift focus detection flow.

First, the designated FA is the real focus detection area FA-
A focus detection flow similar to the conventional one, which matches any one of A, FA-B, and FA-C, will be described. [Step S15] Focus detection (strictly, defocus amount detection) calculation processing is performed by the output of the focus detection sensor pair corresponding to the designated FA. [Step S16] The state of the switch AFSW13 is detected, and if ON, the process proceeds to step S17, and if OFF, the process returns to step 4 in FIG. [Step S17] It is determined whether or not the defocus amount is equal to or less than a predetermined defocus amount. [Step S18] Except for the designated FA, the display is turned off (this is the in-focus display), and the process proceeds to step S35 in FIG.

In step S17, if the object is out of focus, the process proceeds to step S19. [Step S19] When focus detection data is obtained from the subject image in step S15, the process proceeds to step S20. [Step S20] The focus drive system 7 in the lens unit 1 is driven according to the remaining defocus amount, and step S1 is performed.
Return to 5.

If it is determined in step S19 that focus detection data has not been obtained due to low contrast or the like, the process proceeds to step S21. [Step S21] Focus detection impossible (AFNG) display 3
02 is lighted and displayed, and the process proceeds to step S35 of FIG. 6 via.

When it is determined in step S14 that the designated FA does not match any of the real focus detection areas FA-A, FA-B, FA-C, the procedure goes to step S22 in FIG. Then, the shift focus detection flow is started. [Step S22] The closest real focus detection point to the designated FA is selected. [Step S23] The subject image on the designated FA is shifted, and the shift amount of the image required to be superimposed on the real focus detection point is determined as the biaxial drive amount in each of the left, right, up, and down directions.

In this embodiment, the shift optical system 2 using a variable apex angle prism is arranged on the object side of the main lens system,
Since the maximum shake amount with respect to the incident optical axis is constant, the focal length is detected by the position detection encoder of the zoom system 3, the shift amount on the finder is converted into the incident optical axis shake amount, and the drive amount is obtained. [Step S24] The shift optical system (variable apex angle prism) 2 is driven by the predetermined amount obtained in step S23. [Step S25] Focus detection calculation processing is performed at the actual focus detection point for the subject image on the designated FA. [Step S26] The state of the switch AFSW13 is detected, and if ON, the process proceeds to step S27, and if OFF, the process returns to step 4 in FIG. [Step S27] Similar to step S17, it is determined whether or not the defocus amount is equal to or less than a predetermined defocus amount. If the focus is determined, the process proceeds to step S28. [Step S28] The drive operation in the above step S22 is performed in reverse, and the subject image is returned to the initial position before the shift operation. [Step S29] Similar to step S18, all other than the designated FA are extinguished and displayed (this is the in-focus display), and the process proceeds to step S35.

In step S27, if out of focus, the process proceeds to step S30. [Step S30] If focus detection data is obtained from the subject image in step S15, the process proceeds to step S31. [Step S31] Similar to step S28, the shift return drive is performed. [Step S32] The focus drive system 7 of the lens unit 1 is driven according to the remaining defocus amount, and the step S24 is performed.
Return to.

If it is determined in step S30 that focus detection data has not been obtained due to low contrast or the like, the process proceeds to step S33. [Step S33] Similar to steps S28 and S31, the shift return drive is performed. [Step S34] The focus detection impossible (AFNG) display portion 302 is lit and displayed, and the process proceeds to step S35. [Step S35] The state of the switch AFSW13 is detected, and if ON, the process waits at this step, and then OF
When F, the process proceeds to step 36. [Step S36] Focusing or turning off the display of AFNG and returning to the main program of the camera.

FIG. 7 is a diagram for explaining the operation of the above-described embodiment during actual use together with the superimpose display state in the finder. In this example, the manual selection mode is selected,
It is assumed that the shift amount of the shift optical system 2 is sufficiently large both vertically and horizontally, that is, the most focus detection points shown in the menu display state A of FIG. 8 can be selected.

FIG. 7A shows a scene which is a subject.

FIG. 7B shows an initial display during the loop operation of steps S4 to S9 after the power is turned on.

FIG. 7C shows a state in which the scenery (defocused state) of FIG. 7A is then framed and the focus detection point is manually moved to the center row in the second column from the right.
Only the designated FA is displayed blinking.

FIG. 7D further shows a switch AFSW13.
Is turned on, and when this is turned on, the field is shifted to the left by 1 FA (L3), and the actual focus detection point C
The image on the designated FA shown in FIG. 7C is superimposed on [C in FIG. 3B] and the focus detection is performed.

When the signal for focus detection can be formed, the shift is returned once (when the object is out of focus), and after the state shown in FIG. 7C, focus driving is performed to the tree in the figure. And focus is achieved [state of FIG. 7 (e)].

Here, the shift operation is performed again in the same manner, the refocusing is detected, the focus is confirmed, and the shift is returned to the original state.
As shown in (f), the display other than the designated FA is extinguished and the blinking of the FA is turned on to display the focus, and the AF is completed.

FIG. 7 (g) is a diagram in which the FA of the upper first row at the right end is set at the time of FIG. 7 (c) in which the same landscape is framed, and focus detection is performed in a uniform luminance portion without clouds or the like. 6 shows a state in which the AFNG display of step S34 is performed after step S22 to step S26 of step 6, step S27, step S30, and step S33.

The relationship between the display when the line-of-sight input is selected and the operation during actual use is almost the same except that the manual selection mode display unit 303 of FIG. 3A is replaced with the line-of-sight input mode display unit 304. It is the same and it is not difficult to imagine, so it is omitted.

In the use in the line-of-sight input mode, when the input accuracy is high and the shift operation, the focus detection, and the focusing operation are performed at sufficiently high speed, the viewpoint is focused with a slight delay after the line-of-sight is input. In view of the fact that a large number of FA displays as in the embodiment impair the clear field of view as in the embodiment, it is preferable that the user can always turn off the light in consideration of the disadvantage.

According to this embodiment, a shift optical system (as long as the image point is shifted on the image plane, a tilt optical system using a variable apex angle prism is included) and a plurality of focus detection points are selected and designated. By cooperating the means and the focus detection means (group) whose number is smaller than FA that can be designated by the means, multi-point focus detection can be performed without increasing cost and space.

Further, by detecting the focus in the shifted state, and then re-shifting and returning to the original image field, it is possible to detect the multipoint focus with a fixed composition.

Similarly, since focus drive is performed after returning to the initial image field, a momentary image fluctuation (shift focus detection operation)
Just by adding, the operation becomes the same as that of the conventional so-called AF single-lens reflex camera, and the discomfort is greatly reduced.

In addition, a shift information storage means (memory 9) relating to the maximum shift amount of the lens used and / or the shiftable direction is provided, and a selectable focus detection point or focus detection area is superimposed and displayed. By displaying in the system 33, the expansion status of the focus detectable area according to the present case is appropriate even when the photographing optical system and / or the shift optical system is exchanged or the state changes (for example, when the focal length changes during zooming). It becomes possible for the finder observer to grasp,
Operability is good.

Further, even if a non-shiftable lens is used for lens exchange, the operability is equivalent to that in the past, and there is an effect that the compatibility problem of the focus adjusting device having the interchangeable lens system does not occur.

[0060]

As described above, according to the present invention,
When the focus detection point that does not correspond to the focus detection means is selected by the selection means, the image shift operation is performed by the shift means prior to the start of the focus detection operation, and the focus detection point position of the focus detection means is selected. An optical device in which the control device is provided to substantially match the images corresponding to the focus detection points, perform the focus detection operation, and adjust the focus of the imaging optical system based on the obtained focus state signal, and the device is mounted. The image shift operation is performed by the shift means without moving the position of, and the image corresponding to the selected focus detection point is substantially aligned with the focus detection point position of the focus detection means so that the focus detection operation is performed. ing.

Therefore, it is possible to provide a focus adjusting device capable of performing multipoint focus detection without increasing cost and space.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a single-lens reflex camera equipped with a focus adjustment device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an upper surface operation unit and switches of the single-lens reflex camera shown in FIG.

FIG. 3 is a diagram for explaining display contents of a superimpose display system in a viewfinder of the single-lens reflex camera shown in FIG.

4 is a flowchart showing an operation of the single-lens reflex camera shown in FIG.

5 is a flowchart showing a continuation of the operation of FIG.

FIG. 6 is a flowchart showing a continuation of the operation of FIG.

FIG. 7 is a diagram for explaining an operation during actual use in an embodiment of the present invention together with a superimpose display state in the finder.

FIG. 8 is a diagram for explaining display of a menu (focus detection possible area) in the embodiment of the present invention.

[Explanation of symbols]

 2 shift optical system 4 focus system 9 memory 10 lens microprocessor 11 camera microprocessor 12 focus detection point selection mode switching means 13 switch for starting focus adjustment operation 15 focus detection point selection switch 16 focus detection system 25 line-of-sight input system 33 Superimpose display system

Claims (5)

[Claims] 1. A focus adjusting device comprising a shift means for shifting an image on an image plane and a finder means for making it possible to substantially observe a formed image field image, thereby selectively detecting focus at a plurality of positions in the finder. Selecting means for designating a point, focus detecting means having a smaller number of focus detecting points than the selectable number of focus detecting points at the plurality of positions, and the selecting means selecting a focus detecting point not corresponding to the focus detecting means In this case, prior to the start of the focus detection operation, the shift operation of the image is performed by the shift means, and the image corresponding to the selected focus detection point is made to substantially coincide with the focus detection point position of the focus detection means to perform the focus detection. A focus adjusting device, which is provided with a control means for performing an operation and adjusting the focus of the imaging optical system based on the obtained focus state signal. 2. The image processing apparatus, wherein the control means drives the shift means at least after the shift operation and after acquiring a signal necessary for focus detection, and re-shifts the shifted image to restore the original image field. The focus adjusting device according to claim 1, further comprising field returning means. 3. The control means is means for performing the focus adjustment operation of the imaging optical system after the image shifted by the instruction of the image field returning means is reshifted and returned to the original image field. The focus adjusting device according to claim 2, which is characterized in that: 4. A storage means for storing shift information of at least the maximum shift amount or shiftable direction of the shift means is provided, and a focus detection point selectable based on the information stored in the storage means, or 4. The focus adjusting device according to claim 1, further comprising display control means for variably displaying the focus detection area on a superimpose display system provided in the finder means. 5. The focus adjusting device according to claim 1, wherein the shift means is an optical system which is also used as an anti-vibration lens.