JPH0277054A - Camera - Google Patents

Abstract

PURPOSE:To perform a focusing action with higher accuracy for a moving object by providing a decision reference altering means which makes a set speed higher in proportion as magnification gets larger and a focal distance becomes longer based on the results detected by a photographic magnification detection means and a focal distance detection means. CONSTITUTION:A microcomputer muC constitutes the focal distance detection means for detecting the focal distance of a photographic lens, an object speed detection means for detecting the moving speed of the object in a far-and-near direction and a photographic magnification discrimination means for judging the photographic magnification. Moreover, it constitutes a focusing control means for having the photographic lens moved by focusing means muC, LECON and M when the moving speed of the object is higher than the set speed in a moving body corresponding state. By altering the set speed to become higher in the case of the large magnification, when a distance to the object is short and the depth of field is shallow, the detection of the moving speed is prevented from being too sensitive. Thus, a desirable photograph where sharp focusing is attained can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-lens reflex camera capable of automatic focusing operation.

[Conventional technology]

In a single-lens reflex camera, when taking a picture, the mirror retracts (hereinafter referred to as "mirror up") in order to switch the state in which the light beam from the subject is reflected from the viewfinder optical system to the state in which it reaches the photosensitive material such as film. is necessary. During this operation, the focus detection means cannot receive the beam of light from the subject, so automatic focus adjustment cannot be performed. Even if the camera is in focus before the mirror is raised, the photograph may be out of focus because the subject moves while the mirror is raised.

Therefore, in order to avoid such inconvenience, the moving speed of the subject in the far and near directions is detected, and if the detected speed is greater than the set speed, the subject is determined to be a moving object, and for example, the subject is moved immediately before the mirror is raised. Based on the detected deviation, the focus adjustment operation continues even when the mirror is raised,
Alternatively, in addition to this, the focus adjustment operation may be performed based on a composite deviation obtained by adding information on the predicted movement amount of the subject during mirror up, which is obtained using the detection speed, to the detected deviation immediately before mirror up. There is a known device in which the focus adjustment means is operated in a state corresponding to a moving object.

However, even if the objects move at the same speed,
Since the rate of change in focus due to the movement of a subject located near the camera is greater than that of a subject located far away, if a constant speed is used as the speed setting, it is difficult to achieve the intended purpose. difficult to achieve. Therefore, the applicant first proposed a method in which the set speed for determining whether the subject is a moving object is changed according to the magnitude of the photographing magnification by detecting the photographing magnification. .

[Problem to be solved by the invention]

However, the above-mentioned camera had the following problems.

In other words, even when the photographing magnification is the same, the larger the focal length of the photographing lens, the greater the rate of change in focus deviation due to movement of the subject. This is because the hyperfocal distance, which is related to the depth of field, is proportional to the square of the focal length. However, in the above-mentioned camera, the set speed for moving object discrimination was changed depending on the magnitude of the photographing magnification, and since the photographing magnification is proportional to the focal length itself, it is difficult to perform sufficiently fine-grained motion discrimination control. I couldn't do it.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a camera that can more precisely discriminate moving objects and perform more precise focus adjustment operations for moving objects.

[Means to solve the problem]

A characteristic configuration of the camera according to the present invention includes a focus detection means for detecting a deviation from a focus position of a photographic lens with respect to a subject, and a focus detection means for moving the photographic lens toward the focus position based on the detected deviation by the focus detection means. A focus adjusting means, a subject speed detecting means for detecting the moving speed of the subject in the far and near direction, and when the detected speed by the subject speed detecting means is larger than the set speed, for example, the speed of the subject determined using the detected speed is Focus adjustment control means for operating the focus adjustment means in a state corresponding to a moving object, such as operating the focus adjustment means using a composite deviation obtained by adding a predicted deviation corresponding to the predicted movement amount to the detected deviation by the focus detection means; and a photographing magnification detecting means for detecting photographing magnification, a focal length detecting means for detecting the focal length of the photographing lens, and the larger the magnification is based on the detection results of the photographing magnification detecting means and the focal length detecting means. Further, a determination criterion changing means is provided which changes the set speed to a greater extent as the focal length becomes longer.

[For production]

In other words, when shooting using lenses with the same focal length,
When using high magnifications where the distance to the subject is short and the depth of field is shallow, change the setting speed to a high value to prevent the detection of moving speed from becoming too sensitive, and at the same shooting magnification, the depth of field can be reduced. In the case of a long focal length state where the object is shallow, the set speed is similarly changed to a large value, so that even if the S/N of the detection of the moving speed becomes poor, it can be correctly determined that the object is a moving object.

Therefore, in both terms of magnification and focal length, the shallower the depth of field, the lower the sensitivity for identifying a subject as a moving object, and the focus adjustment operation is performed by performing the above-mentioned corrections to increase focus accuracy. It is possible to do this.

Furthermore, when looking at the above control from a different perspective, the photographic magnification is calculated by dividing the focal length by the photographing distance, and is proportional to the first power of the focal length. Changing the setting speed to a higher value for both of the above means that the setting speed is changed in proportion to the square of the focal length for the subject at the same shooting distance.
Considering that the depth of field is determined from the relationship between the hyperfocal distance and the shooting distance, which is proportional to the square of the focal length, the order of focus accuracy (i.e., the order of the amount of defocus on a photosensitive material such as film) ), it can be said to be rational.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 shows a circuit block diagram of the entire camera.

(μC) is a microcomputer (μC) that performs sequence control of the entire camera and calculations for exposure and focus detection.
(hereinafter referred to as a microcomputer). (LEC) is a lens circuit for a photographic lens that is detachably attached to a camera body (not shown), and transmits information specific to the photographic lens (for example, open F-number, focal length, etc.) to the camera body.

(AFS) is a focus detection circuit that inputs image information obtained by forming an image of light that has passed through the photographing lens through a focus detection optical system (AO) and converts it into an analog electrical signal. This focus detection circuit (AFS) consists of a light receiving circuit (CCD) consisting of a CCD type light receiving element array, a monitoring light receiving element (MC) used for controlling the integration time, and a light receiving element (MC) for monitoring. an integrating circuit (IT) that integrates and outputs the current, a comparator (COM) that compares the output of this integrating circuit (IT) with a predetermined value, and a light receiving circuit (CC).
It is composed of an amplifier circuit (AGC), etc., which amplifies the analog signal from D) according to the output from the integrating circuit (IT).

To briefly explain the operation of this focus detection circuit (AFS), when the microcomputer (μC) outputs an integration start signal (ST), the light receiving circuit (CCD) and the integration circuit (IT) are reset, and each integrates Start. This integrating circuit (I
When the integral output of T) becomes a predetermined value, the comparator (C
When the output of the microcomputer (μC) is inverted, or when the integral timer measured within the microcomputer (μC) reaches a constant value, the microcomputer (μC) outputs an integration end signal (SP).

As a result, the integrated output in the light receiving circuit (CCD) is sent to the transfer register, and then transferred to the microcomputer (μC) via the amplifier circuit (AGC).

The microcomputer (μC) then controls this focus detection circuit (AF
Based on the output from S), the deviation from the in-focus position of the photographing lens with respect to the subject is calculated. That is, a focus detection means is constituted by a focus detection optical system (AO), a focus detection circuit (AFS), and a microcomputer (μC).

On the other hand, the integration circuit (IT) receives the integration end signal (SP).
Input and hold the integral output.

The amplifier circuit (AGC) amplifies the analog signal from the light receiving circuit (CCD) up to eight times according to this output and outputs it to the microcomputer (μC). The microcomputer (μC) has a built-in digital converter (A/D) that converts this analog data into digital data. The above amplifier circuit (
Gain data from the AGC) is also output to the microcomputer (μC).

(LMC) is a photometry circuit that measures the light that has passed through the photographic lens and detects the brightness of the subject.
v,] is output to the microcomputer (μC). (ISO) is
A film sensitivity reading circuit outputs an apex-based digital signal [Sv] corresponding to the film sensitivity to a microcomputer (μC). (DISP) is a display circuit that displays the focus state of the photographing lens, etc.

(ENC) is an encoder that detects the rotation amount of the focus adjustment motor (hereinafter abbreviated as AF motor) (M),
It is output as a pulse (pulse output for a predetermined amount of rotation of the motor (M)) signal to a lens control circuit (LECON), which will be described later. The lens control circuit (LECON) inputs the motor rotation amount (number) signal and motor control (speed and direction) signal from the microcomputer (μC), and based on this, drives the AF motor (M), A pulse signal from the encoder (ENC) is input to detect whether or not the AF motor (M) has rotated by a predetermined amount (motor rotation amount)', and also performs stop control of the AF motor (M). The microcomputer (μC) has a counter inside to know the lens position, and the encoder (
The counter performs a count-up or count-down operation in response to input of a pulse signal from the ENC.

In other words, a microcomputer (μC) and a lens drive circuit (LEC)
ON) and the AF motor (M) constitute a focus adjustment means that moves the photographing lens to a focus position for the subject based on the detected deviation by the focus detection means.

(ASL) is an auxiliary light circuit that emits auxiliary light toward the subject when focus cannot be detected and it is dark. (CD) uses the card circuit of an IC card (not shown) to transfer switch switching information from the outside from the memory inside the card to a microcontroller (μC).
). For example, the switch switching information may include whether only one-shot AF (automatic focus adjustment state in which the lens is not driven after focusing), only Spora AF (focus detection state using a narrow area), or auxiliary AF are available. Optical AF (
Focus detection by emitting the auxiliary light is prohibited.

(BAT) is a power battery and supplies power to all circuits.

(SM) is activated by operating the main switch (not shown).
It is a switch that is opened and closed. (Sl) is a photometry switch that is closed by pressing the first step of the release button (not shown). By closing this photometry switch (Sl), photometry and automatic focus adjustment operations are performed. . (S2
) is a release switch that is closed by a second press operation subsequent to the first press operation on the release button, and when the release switch (S2) is opened, a photographing operation is performed. (Ss/w) is a spot AF (a focus detection state that uses only a narrow area in the center of the three focus detection areas described below) and a wide AF (a focus detection state that uses all of the three focus detection areas that will be described later). This is an AF area changeover switch that changes the focus detection state.

Note that (E2FROM) is a memory IC built into a microcomputer (μC) or externally attached. This memory I
C (E2FROM) is an electrically erasable memory that retains its contents even without power supply. This memory IC (E''FROM) can store camera adjustment data, camera mode switching data, and the like.

This allows you to easily set the camera specifications to match the level and needs of the photographer.

Next, the focus detection optical system (AO
) is shown in FIG. 2.

In Figure 2, (TLI) and (TL2) are lenses that constitute the photographic lens, and both lenses (TLI) and (TL2) are lenses that constitute the photographic lens.
).

(TL2) are distances (PZI) and (PZ2)l (PZ
I<PZ2) (hereinafter, this distance will be referred to as the injection distance). Then, the above-mentioned planned imaging plane (FP
) A field mask (FM) is placed near the field. This field mask (FM) is provided with a horizontally long first rectangular opening (Eo) in the center, and a pair of vertically long second rectangular openings (Eot) and third rectangular openings (EO2) on both sides. ) is provided. Each rectangular opening (E) of the above field mask (FM)
The light beams from the subject that have passed through o), (EOI), and (EO2) are sent to separate condenser lenses (Lo).

(Lot), (LO2) (hereinafter referred to as field mask (FM)
Rectangular openings (Eo), (Eot), (EO2)
Corresponding to, the first condenser lens (Lo), the second condenser lens (Lo +), and the third condenser lens (
LO2). ), respectively, and are focused.

The above-mentioned condenser lenses (Lo), (Lot),
Behind (LO2), an aperture mask (AM) and a re-imaging lens plate (L) are arranged. The reimaging lens plate (
L, ) is a pair of re-imaging lenses (Ll), (Lg) arranged horizontally in the center, and a pair of re-imaging lenses (La), (Lg) arranged vertically on each side. Ll
) and L), (to). The re-imaging lenses (Ll) to (L6) are all plano-convex lenses with the same radius of curvature. (Hereinafter, the field of view mask (
FM) rectangular opening (Eo), (EOI), (PO
2), the central reimaging lens pair (Ll), (L
g) as the first re-imaging lens pair and both re-imaging lens pairs (L
a).

(Ll), (Ls), and (Ls) are respectively referred to as a second re-imaging lens pair and a third re-imaging lens pair. ) Also, the aperture mask (AM) includes each of the re-imaging lenses (Ll
) to (L6), the aperture opening (A1) to
(A6) is provided. This aperture mask (AM) is disposed just in front of the re-imaging lens plate (L), and is in close contact with the flat portion of the re-imaging lens plate (L).

Further behind the re-imaging lens plate (L), there are three C
CD line sensor (Po), (Pop), (PO
2) is provided with a substrate (P). central CCD
The line sensor (PO) is arranged horizontally in the center of the board (P), and the CCD line sensors (PO) on both sides are arranged horizontally in the center of the board (P).
p ), (PO2) are arranged vertically on both sides of the substrate (P), and are aligned with the installation direction of each re-imaging lens pair on the re-imaging lens plate (L) and each of the CCD line sensors ( P
o), (Pop), and (Pot) are arranged in the same direction. The CCD line sensors (Po), (Pot), and (Pot) are respectively connected to the first. It has two second rows of light-receiving elements, and is configured to separately photoelectrically convert two images re-imaged on the CCD line sensor by the re-imaging lens pair.

(Hereinafter, each of the above CCD line sensors (Po), (PO
I), (PO2), the rectangular opening (Eo), (Eo+) of the field mask (FM).

(Eoz), the first CCD line sensor (Po
), a second COD line sensor (Po1), and a third CCD line sensor (PO2). ) The blocks (AFMO) surrounded by dotted lines in the figure are assembled together to form an AF (autofocus) sensor module. And the field mask (FM
) −:I indensor lens (Lo), (Lot).

(Po2)・Aperture mask (AM)・Reimaging lens plate (L
) constitutes a focus detection optical system (AO).

The focus detection device (X) is configured to detect the focus position in the following manner using an image obtained by the focus detection optical system (AO) configured as described above.

The optical axis (O
p) A beam of light for optical axis distance measurement from a subject in an outside area is incident on the field mask (FM) so as to be separated from the optical axis (Op) at a predetermined angle with respect to the optical axis (Op). The light passes through the second rectangular opening (Eo'+) and enters the second condenser lens (Lo I). This optical axis distance measuring light beam is bent and focused by the second condenser lens (Lot) toward the optical axis (Op), and the second aperture aperture (A, ), ( A4) to the second re-imaging lens pair (La) of the re-imaging lens plate (L)
, (Ll). Second re-imaging lens pair (Lg
), (Ll) is focused on the second COD line sensor (Pop) by this second re-imaging lens pair (La), (Ll), A pair of images is re-imaged in the vertical direction on the 2CCD line sensor (Pop).

Similarly, the optical axis distance measuring ray bundle including the principal rays (z5) and (1g) enters the field mask (FM) so as to be separated from the optical axis (Op) at the above-mentioned predetermined angle. 3 rectangular apertures (PO2), a third condenser lens (Log), and a third aperture aperture (A5) of the aperture mask (AM).

(A6) and the third re-imaging lens pair (Ls), (t
, a), and is focused onto the third CCD line sensor (PO2), and a pair of images are re-imaged in the vertical direction on this third CCD line sensor (PO2).

On the other hand, the ray flux for optical axis distance measurement from the subject in the area including the chief rays (Z+) and (1Z) and the optical axis (Op) of the photographing lens is the optical axis (Op) of the field mask (FM). 1st above
rectangular opening (Eo), first condenser lens (Lo),
The first aperture aperture (AI), (A2) on the optical axis (Op) of the aperture mask (AM), and the first re-imaging lens pair (L
l), (Lg), the first CCD line sensor (Po
) and this first CCD line sensor (PO
), a pair of images are re-imaged in the left and right direction.

Then, the CCD line sensor (Po), (Po,
).

(PO2) The focal position of the photographing lens (2) with respect to the subject is detected by determining the positions of the three pairs of re-imaged images formed above.

To explain in correspondence with the viewfinder field diagram shown in Fig. 3, the first CCD line sensor (Po) is located in the on-axis focus detection area (ISI), and the second CCD line sensor (Pop) is located in the on-axis focus detection area (ISI).
is the third CCD in the optical axis focus detection area (IS2) on the right side.
The line sensor (PO2) is located on the left optical axis focus detection area (
IS3). Then, the shooting screen (
Three focus detection areas (ISI) shown by solid lines in the center of the screen for S).

(IS2), (IS3) (hereinafter, when it is necessary to distinguish between them, they will be referred to as the first island (ISI),
2nd island (IS2), 3rd island (IS3)
The camera is configured so that focus detection can be performed on a subject located at In the figure, the rectangular frame (AP) indicated by a dotted line indicates to the photographer the shooting area where focus detection is being performed. The display shown in (
Dfa) indicates the focus detection state, and lights up in green when in focus, and lights up in red when focus cannot be detected. (Dfb) is an LCD for displaying a moving object when a moving object is detected.

Next, the sea fence of camera operation will be explained using the flowchart of FIG.

This flow starts when the main switch (SM) is turned on. First, press the photometry switch (S) with <#400>.
l) is closed, and the photometric switch (S
t) is closed <#400. #405> is looped. In <1405>, it is determined whether the main switch (SM) is opened, and if the main switch (SM) is opened, the microcomputer (μC) enters the stop mode.

If it is determined in <#400> that the photometry switch (Sl) is closed, lens data unique to the photographing lens is input from the lens circuit (LEC) in <#410>.

This lens data includes focal length data [f], a conversion coefficient [K] between the defocus amount and the lens driving amount, and the open F value (Av value) of the photographing lens [Avo].

At <#415>, input the film's ISO setting data [Sv] from the film sensitivity reading circuit (ISO), and press <#4
20>, a photometric operation is performed and photometric data [By] is input from the photometric circuit (LMC). At <#425>, a subroutine (AP) for performing an automatic focus adjustment operation is called, the details of which will be described later. Exposure calculation is performed in <#430>, and the shutter speed [Tv] and aperture value [Av] for which exposure should be controlled are determined.
] is calculated.

Next, it is determined whether the release switch (S2) is closed at <#435>, and if it is closed, <144
0>, a release permission flag, which will be described later, is used to determine release permission. If the release is permitted, proceed to <#450> and release time lag - release switch (S2
), a subroutine (LNS) for calculating the drive amount of the photographic lens and controlling the lens drive is called to compensate for the shift in focus that occurs during the time delay between the closing of the lens and the exposure (the details will be described later).

If the release switch (S2) is not closed in <#435> and if the release is not permitted in <#440>, it is determined in <#445> whether the photometry switch (Sl) is in the open state, If it is open, the process goes to <1400>, whereas if it is closed, the process goes to <#410> for the next photometry/distance measurement.

On the other hand, after performing focus compensation with <#450>,
A subrune (exposure control) that performs exposure control based on the shutter speed [Tv] and aperture value [Av] obtained in #430> is called in <#455>, the details of which will be described later. After that, the film is advanced by one frame in <#460>, and it is determined in <#465> whether the photometry switch (Sl) is in the open state, and if it is in the open state, <#40>
0>Help.

Figure 5 shows the subroutine (
AF).

When this subroutine is called, first
〉Focus detection circuit (AFS) (7) Light receiving circuit (CCD)
Then, in <#502>, the pixel data is converted to A
D-convert and input. <150 using this pixel data
4> calculates the amount of out-of-focus (defocus amount). In <#502>, the card information from the card circuit (CD) is also input, and the continuous A
It can also be seen whether F (an automatic focusing state in which the lens is driven even after focusing) or one-shot AF (an automatic focusing state in which the lens is not driven after focusing) is set. That is, a forced one-shot flag and a continuous flag for forcing one-shot AF (hereinafter referred to as card one-shot) are sent from the IC card.

In <#506>, the (moving object mode) is determined, which will be explained later, but when the subject is determined to be a moving object, the moving object mode flag is set.
This is because in the subsequent loop, if the subject is a moving object based on the determination of this flag, the process branches to the moving object processing flow from <#544>. In the distance measurement in the first loop, it cannot be determined whether the subject is a moving object, so the process always moves to <#508>. Here, Continuous AF
We are determining whether or not.

The I input in <#502> is continuous.
Continuous AF was forcibly set using the card information from the C card, or <#55 (described later)
2> is either due to the continuous flag being set.

Subsequently, in <1510>, it is determined whether or not focus has been achieved using an after-focus flag, which will be described later. This is after focusing <#524
This is to branch to the flow of moving object determination from >. <
At 1512>, it is determined whether the lens is being driven. Then, if the lens is being driven, the next focus determination and moving object determination will be performed with poor precision, so they are skipped. <#514>
Now, it is determined whether the photographing lens is within the in-focus zone. If it is within the focus zone, set the after-focus flag (used in <9510>) with <#520>, and press <#52>.
2>, the focus is displayed (line display on the display section (Dfa) shown in Fig. 3), and the release permission flag (Fig. 4 <#4) is displayed.
40>).

On the other hand, if it is not within the focus zone in <#514>, <#5
16>, determine whether the lens is driven 3 times or more, and
If the amount of defocus is greater than or equal to the amount of defocus, the moving object is determined using the past three defocus amounts in <#518>. If it is determined in <#518> that the object is not a moving object, and if it is determined in <#516> that it has not been driven three or more times, the lens for focus adjustment is driven in <#540> and the main routine returns. return to,
Loop to the next distance measurement from <#500>.

If it is determined in <#510> that the after-focus flag is set, the process proceeds to <#524>, where it is determined whether distance measurement has been repeated four times, and if distance measurement has not been repeated four times consecutively, the process proceeds to <#524>. Return to the main routine and loop to the next distance measurement from <#500>.

When the four distance measurements are completed, in <#526>, the four defocus amounts that are the results of the four distance measurements are averaged to obtain an average defocus amount [DFx]. Then, in <1528>, it is determined whether or not the subject is moving away using the past two average defocus amounts [DFx], and if the subject is moving away, the process proceeds to <#542> and an AF flock flag is set.

Note that in the first loop, two average defocus amounts [D
Since there is no data for [FX], use the same value.

If the subject is not far away in <#528>, <#5
30>, it is determined whether the average defocus amount [DFx] is four or more. This is the following <#53
In the moving object determination of 2>, this average defocus amount [DFx
] is the method that makes a determination only when all four are present. If the average defocus amount [DFx] is not all four, the process returns to the main routine and the next <
Loop to distance measurement from #500>.

If you have four average defocus t [DFx], <#5
32>, moving object determination is performed using the four average defocus amounts [DFx]. If it is determined that the object is a moving object in <#532>, the process proceeds to <1534>. Also, if it is determined that the object is a moving object in <#518>, the process proceeds to <1534>.

In other words, there are two ways to determine that a subject is a moving object: If the subject is moving at a relatively fast speed, <#518> is used; on the other hand, if the subject is moving at a relatively slow speed, the
#532>, each object is determined to be a moving object.<#
534>.

Hereinafter, these will be referred to as "moving object determination type I" and "moving object determination type ■." Then, if it is determined to be a moving object, <
#534> is the moving object mode flag (used in <#506>)
Set it, calculate the motion correction in <#536>,
The amount of lens drive is calculated by adding the expected amount of defocus that would occur due to a moving object to the normal amount of defocus.

After that, <#538> displays the moving object (L C shown in Figure 3).
D (display Dfb)) and drive the lens with <#540>. Hereinafter, the operation mode in which the above-mentioned moving object correction and lens driving are performed will be referred to as (moving object mode).

After entering (moving object mode) in this way, after driving the lens,
The program returns to the main routine and loops back to <#500>. This time, proceed from <#506> to <#544> to calculate the moving object correction.

However, this <#544> moving body correction calculation is performed by <#53>
Unlike the moving object correction calculation for driving the lens in <#5>,
36>, correction is performed with the goal of completing the next distance measurement, whereas correction is performed with the goal of completing the current distance measurement.

In <#546>, focus is determined based on the corrected value, and if in focus, in-focus display and release permission are performed in <#548>. Subsequently, in <#550>, it is determined whether the direction of movement of the subject has been reversed during (moving object mode).

If it is reversed, set the continuous flag (continuous mode) with <#552>, and press <#552>.
554> to clear the moving object mode.

In other words, if correction is performed even though the moving direction of the subject is reversed, there will be a time delay due to the integration time of the CCD line sensor when detecting the movement of the subject, and there will be a delay in the motion correction itself. This is because continuous AF is better at tracking subjects that move randomly back and forth. It is.

Figure 6 shows “moving object detection type I” and “moving object detection type ■”
This is a sea fence diagram. A relatively fast-moving subject, i.e. approximately 1.3m in film surface terms.
A subject having a speed of m/s1 or more can be detected as "moving object determination type I".

1. Drive the lens with the second distance measurement <A> and <B>,
After focus confirmation distance measurement <C>, moving object detection begins. The reason for this is that in the distance measurements of <A> and <8>, backlash from lens drive is included, the accuracy of focus detection is low due to a large distance from the in-focus position, and the amount of defocus This is because, due to the error in the conversion coefficient [K] of the lens drive amount, the distance measurement in <8> often does not yet enter the in-focus zone. If the subject is stationary, it should be in focus with distance measurement <C>, which has fewer sources of error as described above, but if the object is not in focus even with distance measurement <C>, it means that the subject is a moving object. There is no other way than that. Therefore, after driving the lens based on the distance measurement result of <C>, if the distance measurement of <D> is out of focus and the distance measurement of <E> is also out of focus, enter (moving object mode) for the first time. .

Then, the moving object is corrected using the detected defocus amounts obtained in the three distance measurements <C>, <D>, and <E>. In other words, the moving object speed is calculated by averaging two speeds: the speed calculation using the detected defocus amount by <C> and <D>, and the speed calculation using the detected defocus amount by <D> and <E>. That's what I do.

Until distance measurement <C>, the focusing zone is a narrow zone of [80 μm]. This is based on the assumption that the subject is stationary, and is a size that guarantees focus within this zone. Once within this zone, there is no need to drive the lens thereafter. After the distance measurement of <0>, the focusing zone is set to [2
00 μm]. This is based on the assumption that the subject is moving, and a subject that moves more than [200 μm] in the lens drive cycle based on the result of one distance measurement is determined by "Moving Object Measurement Type I" and the operation mode is set to ( This means switching to moving object mode).

When the object is in focus with respect to the [200 μm] focusing zone, moving object detection thereafter shifts to detection using "moving object detection type (■)". In addition, if an interrupt occurs due to the closing of the release switch (S2) before shifting to "Moving object detection type ■", the drive for the photographing lens during release (Fig. 4<#
450>'). Furthermore, when the focus is achieved by distance measurement of <C>, the moving object is detected as "moving object detection type (■)".

In "Moving Object Detection Type ■", after focus is achieved with confirmation distance measurement <C>, distance measurement is repeated four times in a row with the photographic lens stopped. As shown in Figure 6 (b), <DI>
, <02>, <D3>, and <04> were carried out four times in a row, and the defocus amounts obtained in each distance measurement were averaged to obtain the average defocus amount [DPx].
Repeat distance measurement one time at a time. And <El> ~ <E4>
, <Fl>A<F4>.

When the average defocus amount [DFX] is determined in each of the four distance measurements from <61> to <G4>, a moving object determination is performed using these four average defocus amounts [DFx]. The speed of the object that can be detected with this "moving object detection type (-)" is at least [0.25 mm/s] in terms of film surface. If the subject is detected to be a moving object in this "moving object detection type (■)", the operation mode enters (moving object mode), and moving object correction and moving object display are performed.

FIG. 7 and FIG. 8 specifically show the flow of moving object detection using "moving object detection type ■" and "moving object detection type ■". Corresponding to the flowchart in Figure 5 above, <#5
16>, <#518> are based on the "moving body detection type ■", and <#524> to <#532> are based on the "moving body detection type ■".

In "Moving Object Detection Type I" shown in Fig. 7, first <#71
0>, it is determined whether [LCNT] is "3" or more.

[LCNT] is the number of times the lens is driven <#540> (7
) - This is a drive counter that counts how many times the lens has been driven. By clearing this drive counter when the photometry switch (Sl) is closed, this drive counter is incremented each time <#750> is passed, and is used as a counter for entering moving object determination. The drive counter is determined in <#710>, and if the lens is driven for the third time or more, the subject speed is determined in <#715> (see << in Figure 6).
C> and <D> distance measurement). Subsequently, if the drive counter is "3" at <1720>, the process exits to <1750>. <#720
> and the drive counter is "4"(<D> and <E in Figure 6)
> Distance measurement) Performs moving object determination.

Next, each condition for moving object determination is checked. In other words, using the auxiliary light circuit (ASL) in <#725> (
(auxiliary light AF mode). <#730
> to determine if the subject is dark or absent. It is determined that the image is not dark if the gain of the amplifier circuit (AGC) in the focus detection circuit (APS) is less than 4 times. <
#735>, it is determined that the subject magnification is not high. This is because when the magnification is high, the variation in distance measurement is large and the detection error is large. And in <1745>, <17
15> The previous two subject speeds (obtained from the distance measurement results of <C> and <D> in Figure 6 and from the distance measurement results of <D> and <E>) objects) are in the same direction. Then, when each of the above-mentioned conditions is satisfied, in <#745>, the past two subject speeds are averaged to obtain the subject speed to be used in <#534> and below.

Here, in order to perform the moving object detection using this "moving object detection type I", there is another condition that the object does not enter the in-focus zone, but the detailed flow of this in-focus zone judgment performed in <#514> will be explained using FIG.

In this flow, first check the drive counter in <#910>, and if it is "3" or more, set the focusing zone to [200 μm] in <#920>, and if it is less than "3", <
#930>, set the focusing zone to [80 μm] (distance measurement of <A>, <B>, and <C> in Figure 6).
μm], <D>, <E> [200 μm])
. Therefore, in continuous AF, the focus zone is usually [200 μm]. And <#9
Defocus amount [DF] which is the distance measurement result at 40> and <
The focus zone is compared with the focus zone set in #920> or <#930>, and if in focus, proceed to <#520>; if out of focus, proceed to <1516>.

FIG. 8 shows "moving object determination type (■)". first,
It is assumed that the defocus amount [memory of sum of leaves [DF (sum)] is cleared by closing the photometry switch (Sl). Then, as a result of the determination in <#510>, when the flow after focusing (<#524>~) is entered, in <#800>, the defocus amount [DF (now) and [ DF(sum)] and save to DF(sum). <180
5>, it is determined whether or not the distance measurement has been performed four times in a row, and if the distance measurement has not been performed four times, the process proceeds to <#807> and the first determination counter [ml is counted up. ,
Return to the main routine (<1590>).

Next, in <#810>, a second determination counter [l] that determines how many times the four consecutive distance measurements have been performed is counted up. Note that both these counters [n] and [ml
is assumed to be cleared when the photometric switch (SL) is closed. Further, in <#815>, only the first determination counter [ml is cleared.

<#820> calculates the sum of the four defocus amounts [DF(
Divide the average amount of defocus by 4.
I'm looking for something. In <#825>, it will be described later whether the first value of this average defocus amount [DF (flat)] after focusing (hereinafter referred to as the base defocus amount) [DF,] is stored in memory. Determine using memory flag. If the base defocus amount [DFo] is in the memory, proceed to <#840>, otherwise go to <#830> to set the first average defocus amount [DF (flat)] to the base defocus amount [DF,] ] and <1835
> sets the memory flag (used in <1825>).

In <1840>, the average defocus amount [DF (average)] obtained in <#820> is stored in memory [DF1], and four memories [DF4] and [DF3] are stored.
.

Shift the data in [DF2] and [DF,] in order.

Therefore, the latest average defocus amount [DF (average)] is always stored in the memory [DF,].

In <#845>, <#850>, and <#855>, determination is made to escape from the moving object determination state and perform AF focus.

First, if the subject is determined to be dark in <#845>,
In other words, the amplifier circuit (AGC) of the focus detection circuit (AFS)
) is determined to be 4 times or 8 times,
<#850> The magnification [1
/15], in addition, <#85
5>, compare the latest average defocus amount [DF, ] with the base defocus amount [DF, ] and move away from it [3
00μm] or more, in any case, <#865
> sets the AF flock flag and returns to the main routine (<#590>).

If the AF flock flag is not set, <#86
0>, if it is determined that the latest average defocus amount [DF4] has moved toward the object by more than [400 μm], the object speed [V] is changed to (moving object) without passing through the subsequent moving object determination flow. Set the speed to [0.25mm/s], which is the minimum speed for maintaining the mode).<#534>
Proceed to.

On the other hand, in other cases, the focal length of the photographing lens is determined in <#864> and <#866>, and the moving object determination level from <#875> is switched. If the focal length [f] is determined to be smaller than [50mm1] in <#864>,
If the determination level [Co1 is set to [100 μm] in <#867>, and the focal length [f] is determined to be smaller than [200 mm] in <#866>, the determination level [Co1 is set to [100 μm].
Co1 is [150 μm], focal length [f] is [200 μm]
mm], the determination level [Cn] is set to [200 μm] in <#869).

This judgment level [Co1 is the average defocus amount [DF
This is for determining the difference between two values of (flat).

Note that the switching of the moving object determination level [Co1 performed in <#864> to <#869> can also be performed by another method. An example thereof is shown in FIG. In this example, the switching of the moving object detection level [Co1 is performed by changing the focal length [f] corresponding to the amount of defocus on the film and the photographing magnification [
The product [f·β] with β is used as a criterion for determination.

That is, as a result of the determination in <#864'> and <#866''>, if the product [f·β] is smaller than "5", the moving object determination level [Co1 is set to [100 μm]<#867'
>, if the product [f・β] is "5" or more and smaller than "20", set the moving object detection level [Co1 to [150 μm]<#8
68'>, if the product [f・β] is "20" or more, set the moving object determination level [Co1 to 200 μm<#869'>
, after setting each, proceed to <1870>.

That is, the moving object determination level [C
A microcomputer (μC) that changes o1 constitutes a judgment criterion changing means.

In <#870>, it is determined how many times the four consecutive distance measurements have been performed, that is, whether the average defocus amount [DF (flat)] obtained for each of the four consecutive distance measurements has reached four. death,
If there are four or more, moving object determination is performed from <#875>. This moving object determination consists of [DF, -DF, ≧Cn] and [DF
, -DF2≧Cn] and [DF, -DF,≧1.5・Co
The object is determined to be a moving object if all three conditions 1 and 1 are satisfied. Here, the reason why the determination level is [1,5·Co1 for the last condition is that the span is 1.5 times that in other cases.

Next, in <#895>, calculate the two average defocus amounts [DF
3],, Find the subject speed [■1] using [DF,] and the time between these two distance measurements, and similarly calculate the two average defocus amounts [DF,], [ in <#897>. D
F2] and the time between these two distance measurements to find the subject speed [V2], and <#899> find the subject speed [V1] of those two.

[VZ] After calculating the average speed (V=(Vl+V2)/2) to find the average subject speed [V], <#534>
Proceed to.

Below, in the moving object correction, the average subject speed [V] is used to predict the amount of defocus at the end of the next distance measurement,
The focus adjustment operation is repeated by calculating the lens drive amount in addition to this amount. When the image is focused, a release operation is performed. In the release operation, the release switch (S2) may be closed after focusing, or the release switch (S2) may be closed before focusing. Exposure control is performed by closing the release switch (S2), but the camera is configured so that no light enters the focus detection optical system (AO) during exposure control.

To explain moving object correction using Fig. 1θ, film (F
) is a photographic lens (TL
), the ray flux passes through the finder optical system (F
I) Anti-transmissive main mirror (MM) for reflection
, the light reaches the focus detection optical system (AO) through the total reflection sub-mirror (SM), but when the mirror-up starts under exposure control, the light is reflected elsewhere. At this time, if the subject is a moving object, a shift in focus will occur during the mirror-up. In order to correct the focus deviation during this release time lag (hereinafter, this operation is referred to as focus compensation), the shortfall in the amount of movement of the photographing lens during the release time lag is
This is supplemented by driving the lens during mirror up (hereinafter referred to as driving during mirror up). In the figure, the out-of-focus distance (DF) of the subject is corrected by the above-mentioned mirror-up drive.

FIGS. 11 to 13 show driving during mirror up for focus compensation. The horizontal axis is time, and the vertical axis is an axis related to the position of the image plane.

Figure 11 shows the case of ``Moving object detection type ■'', where <X> represents the integration timing, <y> represents the calculation timing, and (
The curve 0) represents the movement of the subject, and the straight line (L) represents the movement of the photographic lens. The speed of the objects shown in FIG. 11 is quite slow, and the objects shown in FIG. 11 also include objects that have started moving from a stopped state.

As a result of distance measurement <C>, the camera is in focus, and the subject is determined to be a moving object by four consecutive distance measurements <D>, <E>, <F>, <G>, and the distance measurement of <T> is performed. Enter (moving object mode) at the timing. When entering (moving object mode), each calculation ends at <1++>, <1+□>.

The movement of the photographing lens is controlled so that the defocus amount becomes "0" at <tH> and <t+4>. For example, if an interruption occurs between the timing <t's> and the timing <ti+> due to the closing of the release switch (S2), mirror-up starts at the next focusing timing <j+<>. Then, the amount of defocus that deviates during mirror up is corrected by driving during mirror up, and at exposure timing <S>, the photographing lens is moved so that the amount of defocus becomes 0''.

Figure 12 shows the case of “moving object detection type ■”, where the photometry switch (St) and release switch (S) are used from the beginning.
2) is a closed state. Note that the closing of the release switch (S2) is the same operation as shown in the figure, regardless of the timing, until distance measurement of <F> begins. When using “Moving Object Detection Type■”, when shooting a fast-moving subject, distance measurement is less than
A> to <E> are not in focus. Therefore, as explained in FIG. 6, the camera enters (moving object mode) at timing <T> after driving the lens four times, focuses on distance at <F>, and performs a release operation.

In this case as well, driving is performed during mirror up, and the photographing lens is moved so that the defocus amount becomes "0" at exposure timing <S>.

FIG. 13 shows a case in which the same subject as in FIG. 12 is brought into focus at distance measurement <D>, which begins to widen the in-focus zone. In this case, (moving object mode) cannot be entered.

However, considering the range of [200 μm] in the widened focusing zone, a deviation of at least [200 μm] may occur during exposure. Therefore, in order to compensate for this focus shift, <
The amount of defocus (the amount of defocus up to P) determined by the distance measurement of D> is corrected by driving while the mirror is up.

This method makes it possible to eliminate release lag due to out-of-focus without missing a photo opportunity, even if the subject is too small to enter (moving object mode). That is, although the camera is released with the focal zone widened, the out-of-focus caused by widening the focal zone is reduced by driving the lens while the mirror is up.

゛ Table 1 on the next page summarizes this drive during mirror up.

Mirror-up drive does not always occur, but can be switched depending on the autofocus mode.

If you want to fix the focusing because the photographer intended to shake the camera (<#855>), or if the accuracy of motion detection seems to be low, such as when the subject is dark or the magnification is high (<#845> , <#850> ), for slow moving subjects that do not require (moving object mode) (
<1855>') All are AF flocks. During this AF lock, driving while the mirror is up will result in a poor photograph, so do not drive while the mirror is up.

On the other hand, when a moving object approaches or moves quickly, the camera enters the (moving object mode) as described above, so the mirror is driven while it is up, and moving object correction is calculated to ensure that it is in focus at the time of exposure. However, since the mirror-up time is a finite time of about 70 m5, there is a limit to the amount of drive during the mirror-up. The amount that can be driven during this [70m5] is less than normal full drive because the photographic lens needs to be stopped during actual exposure, so the lens must be driven while braking. The pulse count is [40 pulses].

If this value is a shooting lens with a longer focal length than a standard lens [50/1.7], the lens will move more than [200μm], so if the shooting lens is stopped at the edge of the focusing zone [200μm]. Only this value can drive the lens.

If the required lens driving amount exceeds this [40 pulses], the start of mirror up is delayed by [40 m5] and the lens is driven during this time. We also put a limit on the amount of lens drive before the release, so as not to lengthen the release time lag ([increase only by 40m5l]).
Unlike the drive during mirror up, full drive is possible, so the drive amount is secured for [70 pulses], making a total of [110 pulses].
This makes it possible to drive the lens accordingly. This results in
If the conversion coefficient [K] between the defocus amount and the lens drive amount is small, a lens movement amount of [2000 μm] can be secured, and even if the front-rear conversion coefficient [K] is large, it is possible to secure a lens movement amount of [100 μm].
Since it is possible to secure a certain amount of lens movement, this value can be said to be sufficient for focus correction.

Next, in the case of non-moving object mode, in this mode,
If the release switch (S2) is closed before focusing, and the subject is moving at a fairly slow speed, you can immediately perform the release operation while entering (moving object mode). (See Figure 13) P In this case and in the case of continuous AF, the mirror is driven while the mirror is up without any moving object correction (unnecessary in the method of this embodiment).The amount of drive at this time is It is calculated from the results of distance measurement just before close-up.On the other hand, in the case of a stationary subject or a slow-moving subject, the moving object determination is repeated after focusing.

During this time, if an interruption occurs due to closing of the release switch (S2), the mirror is driven while the mirror is up without moving object correction. At this time, it is impossible to determine whether the photographer is trying to photograph a stationary subject or a slow-moving subject.

For example, if you want to focus on AF, if you drive while the mirror is up, the picture will be unintended.

Therefore, if the subject is in the in-focus zone, the drive will not be performed while the mirror is up, if the camera has been shaken, the drive will not be performed while the mirror is up, and if the subject is the same as the one that has just been focused, the moving speed will be slow. Therefore, assuming this, a control method that satisfies the three phenomena of moving the photographing lens a little while driving the mirror up is to set the defocus amount to [7].
0 to 200 .mu.m], the driving is performed during mirror up. p, the amount of defocus is [7
If the amount of defocus is [0 μm] or less, it is within the focus zone, if the amount of defocus is [200 μm] or more, the camera is shaken, and if the amount of defocus is [70 to 200 μm], it is determined that the subject has moved. be.

Next, the driving amount will be explained with reference to FIG. 14.

Since focus was achieved during distance measurement <C>, considering the dispersion in distance measurement, distance measurement <D>, which is averaged, is more accurate. Therefore, during mirror-up driving during moving object determination, the driving amount is determined based on the average defocus amount. First, if the release switch (S2) is closed before entering (moving object mode) assuming that the subject is moving, then the amount of defocus (in Fig. 14) determined from the latest distance measurement results is (Average defocus amount obtained from the distance measurement results of <I>) [It is better to use DFil to drive the mirror while it is up (line (i) in Fig. 14). Also, assuming that the subject is still, the point of focus can be seen in the viewfinder, so the amount of defocus (<D in Figure 14) determined from the distance measurement results immediately after focus is
> average defocus amount obtained from the distance measurement results)
It is better to use [DFd] to drive while the mirror is up (
(line (ii) in FIG. 14). Furthermore, if the premise is that the camera is slightly shaken when the AF is focused (the camera shake is such that it cannot be detected with <#855>), then the measurement will be performed after [approximately 0.8 seconds] after confirming focus. Defocus amount determined from the distance result (<G> in Fig. 14)
The average defocus i [D
It is best to use the Fg]) to drive the mirror while it is up (
(line (ii) in FIG. 14).

Note that the word "premise" here means a camera that emphasizes this. In other words, it is possible to set in advance which distance measurement result to use to drive the mirror while it is up, depending on the intended user of the camera.

For even more detailed control, it is possible to switch which distance measurement result to use to drive the mirror while it is up, depending on the time from focusing to closing the release switch (S2). preferable. As mentioned earlier, the time it takes to shake the camera after focusing is [0
, 8 seconds or [1 second], so by the distance measurement of <G>, which is performed at a timing of [0.8 seconds] after focusing, the timing of <j41> in Fig. 14 will be reached. When an interrupt is generated by closing the release switch (S2), the mirror is driven up using the average defocus amount [DFe] obtained from the latest distance measurement result of <E> at that time.
After the distance measurement of <G>, which is carried out at a timing of [0.8 seconds] after focusing, an interrupt is generated by closing the release switch (S2) at a timing of <t<2> in Fig. 14. If it is, the average defocus amount [DFd] obtained from the distance measurement result of <D> is used to drive the mirror while it is up.

By doing this, it is possible to take a photograph that is in focus even when the camera is shaken in an attempt to focus on AF, and the release operation that matches the photographer's intention is performed only after a period of [0.8 seconds] or more has elapsed.

FIG. 15 shows a schematic flow of a subroutine (LNS) for driving the lens during mirror up, which is called at <#450> of the main routine of FIG.

When this subroutine is called, first <#1500
>, the card one-shot flag input in <#502> of FIG. 5 is determined, and if there is a card one-shot flag, the process proceeds to <#1538> without performing mirror-up driving. In <#1538>, the drive pulse counter [ECNT] for driving the lens is set to '0'', and then the process returns to the main routine.Similarly, in <#1502>, (auxiliary light A
F mode), the process proceeds to <#1538> without driving the mirror up.

This (auxiliary light AF mode) is switched according to the flow shown in FIG. The flow shown in FIG. 19 is a flow that is inserted between <#514> and <#516> in FIG. It has become.

In this flow, first, in <#1900>, it is determined whether the subject has low confidence, that is, the reliability of the focus detection result, and if it is low confidence, that is, if the reliability is low, then in <11902>. Determine whether the subject is dark. This judgment is performed by the focus detection circuit (
It is determined that it is dark when the gain of the amplifier circuit (AGC) of the AFS is twice. This is an Apex digital signal [-1 if it corresponds to Bvl]
corresponds to If it is determined in <#1902> that the subject is dark, the auxiliary light flag is set in <#1904> and then the process returns to the main routine (<#590>
). If it is determined in <#1902> that the subject is not dark, the process returns to the main routine without setting the auxiliary light flag (<#590>).

Then, if this auxiliary light flag is set at the next distance measurement,
When integrating the step <#500>, the auxiliary optical circuit (AS
The auxiliary light is projected onto the subject from L).

Returning to Fig. 15 and continuing the explanation, next, <#1504
> to determine whether it is in (moving object mode). If it is not (moving object mode), then the AF flock flag is determined in <#1506>.

If the AF clock is on, as shown in Table 1, the process proceeds to <#1538> without driving during mirror up.

If the AF clock is not in progress, then it is determined in <#1508> whether continuous AF is being performed.

If it is determined to be continuous AF based on the determination of the continuous AF that exited from (moving object mode) or the continuous AF flag sent from the card circuit (CD), the process advances to <#1514> and the current Set the defocus amount [DF(current)] you have in the memory for driving during mirror up [DFml]. This defocus amount [
DF (now)] is the amount of defocus at the time when focus was determined before entering this flow, and 1. It is not the average defocus amount.

If it is determined in <#1508> that continuous AF is not used, then in <#151 (1>) it is determined whether the base defocus amount [DFo] is stored. ] is not stored, the process still proceeds to <#1514>. An example of this is:
Before focusing, press the metering switch (Sl) and release switch (
S2) are both closed (hereinafter, this is referred to as release start before focusing), and the moving object determination routine of FIG. ]
This means that they do not have . In other words, even when the release starts before focusing, the defocus amount CDF (current) at the time of focusing judgment is
] to drive the mirror up. Also, even during the moving object determination routine, if the initial average defocus amount cannot be calculated, the <11510> determination is made in the same way.
Proceed to #1514>.

On the other hand, if an interruption due to closing of the release switch (S2) occurs during the moving object determination, the process proceeds to <#1512>. In <#1512>, the average defocus amount [D
Set F (flat) to the drive memory [DFml] during mirror up. There are various embodiments of this step <#1512> depending on what kind of shooting situation the camera emphasizes, that is, the premise of the camera. Some examples are shown in FIGS. 16(a) to 16(e).

FIG. 16(a) shows the case of a camera that assumes a stationary subject, and the base defocus amount [DF,] is set in the drive memory [DFml]. FIG. 16 (0) shows the case of a camera that assumes a moving subject, and the latest average defocus amount [DF, ] is stored in the driving memory [DFml
Set to .

Figure 16 (c) shows the case of a camera that is designed for portraiture, and when [0.8 seconds have elapsed since focusing, <G
The focusing average defocus amount [D
Set FGl in the drive memory [DFml. In addition,
When using this flow, <#870> and <
It is necessary to set the focusing average defocus amount [DFGl] by placing the flow shown in FIG. 20 between #875>.

In other words, if the second determination counter [ffi,] is "4", it means that there are four average defocus amounts [DFxl], and it is determined that exactly [0.8 seconds] have passed since in-focus. Therefore, the average defocus amount at this point [DF,
] is set as the in-focus average defocus amount DFGl.

FIG. 16(d) is a case where a versatile camera or a beginner's camera is used, and the time from focusing to the current timing, that is, the opening timing of the release switch (S2), is measured in <#1610>. 1+] and <#l612
> determines whether this time [t3] is less than 1 second, and if it is less than 1 second, it is determined that the camera is not shaken, and at <11614>, the latest average defocus amount [
D'F, ] is set in the driving memory [DFm], and if it is longer than 1 second, it is determined that the camera is being swung midway, and the base defocus amount [DF, ] is set in the drive memory [DFm].

This is to prevent a change in defocus amount caused by shaking the camera with respect to a stationary subject from being mistaken for a movement of the subject.

In other words, if the object moves so slowly that it is not determined as a moving object in the moving object determination flow, the focusing accuracy will be better if the lens is driven using the latest average defocus amount. However, if the lens is driven using the latest average defocus amount, if the camera is gently swung toward a stationary subject, the AF focus judgment will be A.
Instead of being judged as an F focus, the focus will be on a completely different area. In order to prevent such a situation, the value set in the drive memory [DFm] is changed depending on the time from when the camera is in focus until the release switch (S2) is closed.

Fig. 16 (e) is a modification of Fig. 16 (d), in which the average defocus amount [DFG] after focusing is stored to determine the time from in-focus to the occurrence of an interrupt due to closing of the release switch (S2). This is used as a substitute for determining whether or not the Average defocus amount after focusing [If DFGJ is stored, assume that more than 0.8 seconds j have passed after focusing <#
1622> sets the base defocus amount [DF,] in the driving memory [DFm], and if the average defocus amount [DFG] after focusing is not stored, it is used for one-shot AF or moved. As focus compensation for the subject, the latest average defocus amount [DF4] is set in the drive memory [DFm] in <#1620>.

By the way, these were all explained as different embodiments, but
All these flows are included in the microcomputer (μC) program, and the card circuit (CD) and memory IC (E
The above five flows (
By switching between (a) and (e) in FIG. 16, one camera can be set to different operating states.

For example, when assembling the camera, write memo 1 month C (E”FROM).
If you write "t" in the specified address of Figure 16 (a)
If you write "2#", the flow shown in FIG. ,
I written 1'' at the specified address of the card circuit (CD)
If the C card is installed, the flow shown in Figure 16 (a) will be selected, and if the IC card labeled '2'' is installed, the flow shown in Figure 16 (0) will be selected. Good. “ Returning to Figure 15 and continuing the explanation, the drive memory [DF
After any of the average defocus amounts described above is set in <#1516> and <#1518>, the lens drive amount data in the drive memory [DFm] is used to determine whether the mirror up drive is possible.・To make a zone determination of impossibility and drive during mirror up when the lens drive amount is [70μm≦DFm<200μm] <#1520>
Proceed to.

If it is determined in <#1516> that the lens drive amount is less than [70 μm], the mirror-up drive is not performed and the process returns to the main routine. That is, this <#1516
It is thought that the subject that comes to the > step is often a stationary subject, and in this case, there is no need to drive the mirror up while it is within the in-focus zone. It also has the meaning of not making the feel worse when the mirror is up.

Also, with <#1518>, the lens drive amount is [200μm]
If it is determined that the above is the case, the mirror-up drive is not performed and the process returns to the main routine. That is,
If the subject is moving fast, use <#1540> or <#15>
14>, so only subjects with slow moving speed can be photographed.
151B> and the moving speed is slow, the maximum amount of drive during mirror up is [200μ
This is because less than m] is sufficient. Conversely, if the lens drive amount exceeds [200 μm], there is a possibility that the camera was shaken but the AF did not work.

On the other hand, if the process branches to <11514>, it is completely unclear whether the subject is a stationary object or a moving object, so the process proceeds to <#1520> on the assumption that the mirror will be driven while the mirror is up.

If it is determined in <#1504> that the mode is (moving object mode), the process proceeds to <#1540> and starts from the time when the light receiving circuit (CCD) starts integrating the current defocus amount [DF (now)]. Currently, the release switch (S
The time until the closing timing of 2) is measured and set as [t1]. In <#1542>, add the mirror-up time lag [70m5] to this time [t1] and get [t2].
Then, multiply the moving object speed [V] calculated during (moving object mode) in <#1544> by this time [t2] to find the amount of focus deviation [ΔDF] due to the movement of the subject during the time lag from integration to exposure. (Hereinafter, since the moving object correction is performed using this amount of focus deviation [ΔDF], this amount of focus deviation [ΔDF] will be referred to as the moving object correction amount).

Subsequently, in <81546>, the sign of the moving body speed [V] is determined. In this determination, if [V>0], it means that the defocus has increased in the direction of focus, and it is determined that the subject has approached the camera.

If it is determined that the subject is approaching the camera, <#1
550>, the moving object correction amount [ΔDF] is multiplied by a coefficient of [1/4] and added. The reason for this is that even if the subject approaches the camera at a constant speed, the amount of defocus on the image plane does not change at a constant speed, but is a reciprocal function of the speed, and if it is approximated by a straight line, there will be insufficient correction. This is to prevent this from happening. Therefore, as a correction coefficient [1+l/X]
think of. Considering the assumed moving speed of the subject, the above variable [x] is set as an experimental value of [3 to 5].
The results show that the range of .
), the variable [X] is set to [4], and the moving object correction amount [ΔDF] is multiplied by a coefficient of [1+1/4].

Conversely, if it is determined that the subject is moving away from the camera, <#
1548> and set the moving object correction amount [ΔDFI to [1-1/
Multiply by 4 coefficients.

After that, in <#1552>, value correction is applied to the moving object correction amount [ΔDF] in consideration of the error in the conversion coefficient [K] between the defocus amount and the lens drive amount in the photographing lens. To specifically illustrate this value correction, as shown in Figure 18,
The error in the conversion coefficient [K] is large when the shooting lens is open to F.
Since it tends to depend on the value [AVol, the open F value [A
If Vol is larger than the predetermined value [J1], that is, if the photographic lens is dark, the moving object correction amount [ΔD
F] is multiplied by [1,2] times the coefficient, and then the conversion coefficient [
If the value of [K] is small, the amount of lens movement per one count for lens driving is large, so the conversion coefficient [K
] error is large, so in <#1806> the moving object correction amount [ΔDFI is multiplied by a coefficient of [1, 2] to compensate for the lack of correction amount.

After performing the K value correction, <#1554> adds the moving object correction amount [ΔDF] to the current defocus amount [DF (current)].
] is added and stored in the drive memory [DFm],
Proceed to <#1520>.

<#1524>, <#1518>, ゛<#15
In <#1520>, which proceed from <#1520>, the lens drive amount stored in the drive memory [DFm] to be driven during mirror up is multiplied by the conversion coefficient [K] of the photographing lens. Drive pulse counter for [
ECNT]. In <#1522>, the value of the drive pulse counter [ECNT] is the maximum number of pulses that can be driven in a limited time while the mirror is up.
It is checked whether it is larger than 40". If it is determined that it is smaller than 40", the process proceeds to <#1536>, starts lens driving, and returns to the main routine.

On the other hand, at <#1522>, the drive pulse counter [ECN
If the value of T] is determined to be “40” or more,
The lens is driven before starting exposure control, but the amount of drive is also limited. That is, <#
1524>, the value of the drive pulse counter [ECNT] is the sum of "70#", the maximum number of pulses for drive before release, and "40", the maximum number of pulses for drive during mirror up.
Determine whether it is larger than “110”. “110”
If it is determined that this is the case, the pre-release drive pulse counter [EECNT] is set to "70" in <11528> in order to perform the pre-release drive for the maximum [70 pulses]. Also, <#1524> sets the drive pulse counter [
If it is determined that the value of [ECNT] is smaller than "110", the drive pulse counter [BCNT] is set at <#1526>.
The value obtained by subtracting "40" from the value is set in the pre-release drive counter [BECNT].

Next, start the pre-release lens drive at <#1530>, and wait until the pre-release drive pulse counter [EECNT] reaches 0" at '<#1532>. The maximum drive time of this pre-release lens drive is [approx. 40m5] and does not significantly increase the time lag.<#l534
In >, the drive pulse counter [ECNT] is set to "40" so that the remaining lens drive is performed while the mirror is up, and in <#1536>, lens drive is started and the process returns to the main routine.

After returning from the subroutine (LNS), the main routine calls the subroutine (exposure control) in <#455>. FIG. 17 shows the general flow of this subroutine (exposure control).

When this subroutine is called, first <#1724
> to start the mirror up, and <#1726> to start the aperture operation of the photographic lens. Then (moving body mode)
etc., the lens drive has started during mirror up, so the drive pulse counter [ECNT
] Waits until the value becomes "0". Note that if the lens is not driven during mirror up, the drive pulse counter [ECNT] is initially set to "0", so <#1728> passes through immediately. And <#17
After completely stopping the photographic lens at <#173>
2>, wait until '[70m5] has elapsed from the start of mirror up. That is, the mirror-up and diaphragm operation ends at [70m5l. When the mirror up, lens drive during mirror up, and aperture operation are all completed, the exposure operation starts from <#1734>. <
#1734> to run the front curtain of the shutter curtain, <#17
36>, the process waits for the exposure time determined by the calculation in <#430> of the main routine, and in <#1738> the rear curtain of the shutter is run to complete the exposure. Then, return to the main routine. .

The sea fence of the camera operation has been explained above, and the microcomputer (μC) that performs these operations has a focal length detection means that detects the focal length of the photographing lens (TL), and a focal length detection means that detects the moving speed of the subject in the far and near directions. The microcomputer (μC) constitutes an object speed detecting means for detecting the object speed and a photographing magnification determining means for determining the photographing magnification, and the microcomputer (μC) controls the speed of the photographing lens by the focus adjustment means when the moving speed of the object is higher than the set speed. (TL) in a state corresponding to a moving object.

[Another example]

Other embodiments other than those described in the previous embodiments will be listed below.

<'l> The reference values for various determinations that have been made to determine the condition of the subject and the intention of the photographer can be arbitrarily changed.

<2> For static objects, if the subject is judged to be dark, the shooting magnification is large, or the subject is slow and moving away from the camera, driving during mirror up is always prohibited. It is not necessary to set the focus adjustment state, but it may be a moving object focus adjustment state that allows driving while the mirror is up.

<3> In the previous embodiment, when it was determined that the subject was moving at a high speed, the drive amount was corrected during mirror-up drive, but this may be omitted.

<4> In the previous embodiment, the photographic lens is configured to be detachable from the camera body, and lens information specific to the photographic lens is input from the lens circuit (LEC) attached to the photographic lens. Although a camera configured to do so has been described, the present invention can alternatively be applied to a camera in which a photographic lens is provided in a fixed state.

5) In the previous embodiment, a configuration in which three focus detection areas were provided was described, but instead, a plurality of other focus detection areas may be provided, or one focus detection area may be provided. You may also provide only

〔Effect of the invention〕

As described above, the camera according to the present invention performs an automatic focus adjustment operation suitable for a moving object based on detailed and rational moving object discrimination results, thereby achieving better focus tracking for a moving object. By making adjustments, you can now obtain the desired sharply focused photo.

[Brief explanation of the drawing]

The drawings show an embodiment of the camera according to the present invention, in which Fig. 1 is a circuit block diagram, Fig. 2 is a perspective view of the periphery of the focus detection optical system, Fig. 3 is a field view of the finder, and Figs. Figure 5・
Figures 7 to 9, Figure 15, Figures 16 (a) to (e), and Figures 17 to 21 are flowcharts showing camera operations, and Figures 6 (a) and (b) are focus A schematic diagram showing the sea fence of the detection operation, Figures 1O (a) to c) are schematic diagrams showing the relationship between the movement of the subject and the camera operation, and Figures 11 to 14 are time charts of the focus adjustment operation, respectively. It is. (TL)...Photography lens.

Claims (1)

[Scope of Claims] 1. Focus detection means for detecting a deviation from the in-focus position of the photographing lens with respect to the subject, and a focus for moving the photographing lens toward the in-focus position based on the detected deviation by the focus detection means. an adjusting means, a subject speed detecting means for detecting the moving speed of the subject in the far and near direction, and a focus adjustment for operating the focus adjusting means in a state corresponding to a moving object when the detected speed by the subject speed detecting means is higher than a set speed. a control means, a photographing magnification detecting means for detecting a photographing magnification, a focal length detecting means for detecting a focal length of the photographing lens, and a magnification that is large based on the detection results of the photographing magnification detecting means and the focal length detecting means. The camera is provided with a determination criterion changing means that changes the set speed to a greater extent as the focal length increases. 2. When the speed detected by the subject speed detecting means is larger than the set speed, the focus adjustment control means causes the focus detecting means to calculate a predicted deviation corresponding to the predicted movement amount of the subject obtained using the detected speed. 2. The camera according to claim 1, wherein the focus adjustment means is operated using a composite deviation taken into account the detected deviation.