JPH0277050A - Camera - Google Patents

Abstract

PURPOSE:To accomplish a focusing action with little sense of incongruity for a finely moving object by providing a focusing control means for inhibiting the actuation of a focusing means for moving a photographic lens to a focusing position when the absolute value of deviation from a focusing position is equal to or under a subsidiary set value smaller than a set value for discriminating focusing. CONSTITUTION:When a release starting signal is outputted in order to actually perform photographing after permitting a releasing action once a focusing state is attained, a microcomputer muC being the focusing control means actuates the microcomputer muC being the focusing means, a lens driving circuit LECON and an AF motor M if the absolute value of deviation exceeds the subsidiary set value based on the absolute value of deviation detected by an optical system for detecting focus AO being a focus detection means when the above-mentioned signal is outputted, a focus detection circuit AFS and the microcomputer muC. Meanwhile, when the absolute value of the detected deviation is equal to or under the subsidiary set value, the actuation of the focusing means is inhibited in order not to change the position of the photographic lens. Thus, the deviation of focus can be prevented from occurring.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a camera capable of automatic focusing operation, and more specifically, a camera that detects a deviation from the in-focus position of a photographic lens with respect to a subject. a focus detecting means; a focus determining means for permitting a release operation when the absolute value of the deviation detected by the focus detecting means is less than a set value; The shutter is also provided with a focus adjustment means that moves toward the in-focus position by a drive amount based on the detected deviation by the means, and the shutter is activated even after a release start signal is output in conjunction with the operation of the release button to actually perform a shooting operation. This is a camera with an automatic focus adjustment function that allows you to take photos with higher focus accuracy by moving the photographic lens and adjusting the focus with better tracking ability for moving subjects. Regarding.

[Conventional technology]

Conventionally, in the above-mentioned camera, the focus detection means is repeatedly operated even after the camera is in focus, and the photographing lens is always moved toward the focus position using a drive amount based on the detected deviation obtained as a result. It is known to control the operation of a focus adjusting means in this manner.

[Problem to be solved by the invention]

However, the conventional camera described above has the following problems.

In other words, even after the camera is in focus, the photographic lens continues to move if there is a deviation from the in-focus position until the shutter starts operating. Although it is possible to take pictures with a small amount of focus, even if a mostly stationary subject moves even slightly, the photographic lens will always try to move to the in-focus position for the subject, so it will actually be in the in-focus state and there will be no out-of-focus. The focus adjustment operation is performed even in response to slight movements of the subject that would never occur, which may give the photographer a sense of strangeness or anxiety.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a focus that does not give a sense of discomfort when photographing a subject that moves only slightly, while enabling focus adjustment operations that have good tracking performance for moving subjects. An object of the present invention is to provide a camera with an automatic focus adjustment function capable of performing adjustment operations.

[Means to solve the problem]

The characteristic configuration of the camera according to the present invention is such that the absolute value of the deviation from the in-focus position detected by the focus detection means at the time when the release activation signal is output is equal to or less than a sub-set value that is smaller than the set value for focus determination. The present invention is provided with a focus adjustment control means for prohibiting the operation of the focus adjustment means for moving the photographing lens toward the in-focus position in this case.

[For production]

In other words, when a release activation signal is output to actually take a picture after the camera is in focus and the release operation is permitted, the focus adjustment control means adjusts the absolute value of the detected deviation by the focus detection means at that time. Based on the detected deviation, if it exceeds the sub-setting value, the focus adjustment means is activated and the photographing lens is moved toward the in-focus position by the amount of drive based on the detected deviation, while the absolute value of the detected deviation exceeds the sub-setting value. In the following cases, no out-of-focus will occur, so the operation of the focus adjustment means is prohibited to prevent the position of the photographic lens from changing.

Therefore, for a fast-moving subject, that is, a subject that immediately deviates from the sub-set value even after it has been brought into focus, the shutter may not be activated even after the release activation signal is output. Until the start of the operation, focus adjustment is always performed to bring the photographic lens as close as possible to the in-focus position on the subject, while focusing on subjects with little movement, i.e. - Once in focus, For subjects that only produce deviations that do not exceed the set value, even if there is some deviation, it will not be enough to cause a focus shift, so there will be almost no apparent movement after the release activation signal is output. It is possible to shift to exposure with the photographic lens fixed, which feels most natural to a photographer who is trying to photograph a subject that is not present.

Moreover, since the sub-setting value is smaller than the setting value for focus determination, when photographing an extremely slow-moving subject, the slight movement from the moment the release operation starts and focus detection cannot be performed until the exposure is detected. Even if the absolute value of the deviation slightly exceeds the sub-setting value, the focus adjustment operation is performed, so it is possible to avoid a situation where the absolute value of the deviation exceeds the setting value for focus determination, which may cause out-of-focus. There is no such thing.

〔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.) that 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).

The integrated output in the light receiving circuit (CCD) is then sent to a transfer register, and sequentially transferred to a microcomputer (μC) via an 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 amount of rotation of the focus adjustment motor (hereinafter abbreviated as AF motor), and sends a pulse (motor (
It is output as a pulse) signal that is output for a predetermined amount of rotation of M). 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, it is detected whether the AF motor (M) has rotated by a predetermined amount (motor rotation amount), and the stop control of the AF motor (M) is also performed. The microcomputer (μC) has a counter inside to know the lens position, and the encoder (EN
The counter performs a count-up or count-down operation in response to input of a pulse signal from C).

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 spot AF (focus detection state using a narrow area), or whether auxiliary light is available. There is a prohibition of AF (focus detection by emitting the auxiliary light). (B
AT) is a power battery and supplies power to all circuits.

(S M ) is a switch that is opened and closed by operating a main switch (not shown). (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 pressing operation subsequent to the first pressing operation on the release button, and by closing this release switch (S2), a photographing operation is performed. (Ss/w) is spot AF
(Focus detection state using only the narrow center area of the three focus detection areas described later) and Wide AF (3 focus detection conditions described later)
(Focus detection state using all three focus detection areas)
This is an AF area changeover switch that switches between

Note that (E2FROM) is a memory IC built into a microcomputer (μC) or externally attached. This memory I
C (E"FROM) is an electrically erasable memory that retains its contents even when no power is supplied. This memory IC (E2FROM) stores camera adjustment data, etc. Camera mode switching data, etc. can be stored.

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 (Pz+) 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) has a horizontally long first rectangular opening (EO) in its center, and a pair of vertically long second rectangular openings (Pot) and third rectangular openings (Eoz) on both sides. ) is provided. Each rectangular opening (E) of the above field mask (FM)
The beams of light from the subject that have passed through o), (Eo,), and (EO2) are sent to separate condenser lenses (Lo).

(Lot), (LO2) (hereinafter referred to as field mask (FM)
The light passes through the first condenser lens (referred to as LoL second condenser lens (Log) and third condenser lens (Lot)) corresponding to the rectangular openings (Eo), (Pot), and (EO2), respectively. configured to be focused.

The above-mentioned condenser lens ° (Lo), (Lot)
, (Log), an aperture mask (AM) and a re-imaging lens plate (L) are arranged. The re-imaging lens plate (L) includes a pair of re-imaging lenses (LL) and (L2) arranged horizontally in the center, and a pair of re-imaging lenses arranged vertically on each side. Pair (La), (L
4), (Ls), and (La). The re-imaging lenses (Ll) to (L6) are all plano-convex lenses with the same radius of curvature. (Hereinafter, the rectangular opening (Eo), (EOI), (
EO2), the central reimaging lens pair (L, ),
(L2) is the first re-imaging lens pair, and both re-imaging lens pairs (La).

(L4), (Ls), and (Le) 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 (L,
) 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).

The re-imaging lens plate (further behind the Ln, there are three C
CD line sensor (Pa), (POI), (PO2
) is provided. The central CCD line sensor (Po) is arranged horizontally in the center of the board (P), and the CCD line sensors (Pot) on both sides are arranged horizontally in the center of the board (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 CCD line sensor (PO2).
), (Pot), and (PO2) are arranged in the same direction. The above CCD line sensor (
Po), (Pop), and (Po□) are 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
t), (PO2), the rectangular opening (Eo), (Eo +) of the field mask (FM).

(PO2), the first CCD line sensor (PO2)
), a second CCD line sensor (POl), 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
)・Condenser lens (Lo), (Lo,).

(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 (Log). This optical axis distance measuring light beam is converted to the optical axis (O
p) side is bent and focused, and the aperture mask (
AM), the second re-imaging lens pair (Id), (L) of the re-imaging lens plate (L) passes through the second aperture apertures (A3), (A4) of
4). Second re-imaging lens pair (L3), (L
4) The optical axis distance measuring light beam incident on this second
2nd C by reimaging lens pair (L,+), (L,)
This second C is focused on the CD line sensor (Pop).
A pair of images is re-imaged in the vertical direction on the CD line sensor (Pot).

Similarly, the optical axis distance measuring ray bundle including the principal rays (ls) and (16) enters the field mask (PM) so as to leave the optical axis (Op) at the predetermined angle. 3 rectangular apertures (PO2), a third condenser lens (Lo□), and a third aperture aperture (As) of the aperture mask (AM).

(A6) and the third re-imaging lens pair (Ls), (L
s), and is focused onto the third CCD line sensor (PO2), and a pair of images is re-formed in the vertical direction on this third CCD line sensor (Po□).

On the other hand, the ray flux for optical axis distance measurement from the subject in the area including the principal rays <1+) and (72) and the optical axis (Op) of the photographing lens is the optical axis (Op) of the field mask (FM). 1st above
rectangular opening (go), 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), (Lm), the first CCD line sensor (P
This first CCD line sensor (PO
), a pair of images are re-imaged in the left and right direction.

And the above CCD line sensor (Po), (Pop
).

(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).
The third CCD is located in the optical axis focus detection area (132) 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 (ls3)
The camera is configured so that focus detection can be performed on a subject located at Note that in the figure, a rectangular frame (AF) indicated by a dotted line is displayed to show the photographer the photographing area where focus detection is being performed. In addition, the display section shown outside the shooting screen (S) (
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
l) is closed <#400. #405> is looped. In <#405>, 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 amount of defocus and the lens driving light, and an open F value (Av value) [Avo] of the photographic lens.

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 [Bv] is input from the photometric circuit (LMC). At <#425>, a subroutine <<AF>> 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] to be subjected to exposure control are calculated.

Next, it is determined whether the release switch (S2) is closed at (#435>, and if it is closed, □<#4
40>, a release permission flag, which will be described later, is used to determine release permission. If release permission is granted <#450>
Proceed to release time lag - release switch (S
In order to compensate for the shift in focus that occurs during the time delay between closing and exposure in 2), a subroutine (L N S ) is called that performs the photographing lens drive l calculation and lens drive control. will be described later.

If the release switch (S2) is not closed in <#435>, and if 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 <#400>, 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>,
430>, the shutter speed [Tv] and aperture value [
A subrune (exposure control) that performs exposure control based on [Av] is called at <#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, <#400>
>Help.

Figure 5 shows the subroutine (
AF>> shows a general flow.

When this subroutine is called, first <#50
0>, the light receiving circuit (CCD) of the focus detection circuit (AFS')
Integrate the pixel data by <9502>.
D-convert and input. Using this pixel data, <#50
4> calculates the amount of out-of-focus (defocus amount). In <#502>, card information from the card circuit (CD) is also input, and 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. In other words,
A forced one-shot flag and a continuous flag (hereinafter referred to as card one-shot) for forcing one-shot AF 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>. During distance measurement in the first loop, it is not possible to determine whether the object is a subject or a moving object, so be sure to
#508>. Here, it is determined whether continuous AF is used.

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.

Next, in <#510>, 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 >. <
In #512>, 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 <#510>) with <#520>, and <#522>
> to display the focus (line display on the display section (Dfa) shown in Fig. 3) and release permission flag (Fig. 4 <#44).
0)).

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 the object has not been driven three times or more, the lens is driven for focus adjustment in <1t540> and the process returns to the main routine. Return and 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, 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, which are the results of the four distance measurements, are averaged to obtain the average defocus m[DFxl. And <#528>
Then, it is determined whether or not the subject is moving away using the past two average defocus amounts [DFxl. If the subject is moving away, the process proceeds to <#542> and sets an AF flock flag.

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

If the subject is not far away in <#528>, <#5
30>, it is determined whether the average defocus amount [DFxl is 4 or more. This is the following <#53
In the moving object determination of 2>, this average defocus amount [DFx
This is because the method makes a determination only when four l's are present. Then, if the average defocus amount [DFxl is not 4, the process returns to the main routine and the next <
Loop to distance measurement from #500>.

Average defocus amount [If you have 4 DFxl, <#53
2>, a moving object is determined using the four average defocus amounts [DFxl. 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 <#534>.

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, <#
Set the moving object mode flag (used in <#506>) in <#534>, calculate the moving object correction in <#536>, and add the predicted amount of defocus that will occur due to a moving object to the normal defocus amount. to find the lens drive amount.

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, the moving object correction calculation of this <#544> is
＞Unlike the moving object correction calculation for lens drive, ＜#53
In 6>, 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 <1550>, 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 <
Clear the moving object mode with #554>.

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 ■" and "Moving object detection type ■"
This is a sea fence diagram. A relatively fast-moving subject, i.e., the mouth is approximately 1.3 m in terms of film surface.
[m/s] or more can be detected as a "moving object detection type".

1. Drive the lens with the second distance measurement <A> and <8>,
After focus confirmation distance measurement <C>, moving object detection begins. The reason for this is that in the distance measurements of <A> and <B>, backlash from lens drive is included, or the focus detection accuracy is low due to a large distance from the in-focus position, or the amount of defocus This is because in many cases, the focus zone is not yet within the focus zone in distance measurement <B> due to errors in the conversion coefficient CK of the lens drive amount]. 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 <D>, the focusing zone is set to [2].
00 μm]. This is based on the assumption that the subject is moving, and if the subject moves more than [200 μm] in the lens driving cycle based on the result of one distance measurement, it is judged as "moving object measurement type" and the operation mode is set to ( This means switching to moving object mode).

200 μm], moving object detection thereafter shifts to detection using "moving object detection type (2)". 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>
, <D2>, <03>, and <04> are carried out four times in a row, and the defocus amounts obtained in each distance measurement are averaged to obtain the average defocus amount [DFx].
Repeat distance measurement one time at a time. And <El> ~ <E4>
, <FD~<F4>.

When the average defocus m [DFx] is determined in each of the four distance measurements from <G1> to <G4>, moving object determination is performed using these four average defocus amounts [DFXE].

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 as a moving object using this “Moving Object Detection Type■”, the operation mode will be set to (Moving Object Mode).
and performs moving object correction and moving object display.

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 the “Moving Object Detection Type” shown in Fig. 7, first <#71
0>, it is determined whether El, CNT, and l are "3" or more.

[LCNT] is a drive counter that counts the number of lens drives <1540>. 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. Check the driving counter in <#710>, and if the lens is driven for the third time or more, <#7
15> to find the subject speed (<C> and < in Figure 6)
D> distance measurement). Next, if the drive counter is "3n" in <#720>, go to <#750>. If the drive counter is "4" in <#720> (distance measurement of <D> and <E> in Figure 6), there is no moving object. Make a judgment.

Next, check each condition for imperial envoy determination. In other words, using the auxiliary light circuit (ASL) in <#725> (
auxiliary light AP mode). <#730
> to determine that the subject is not dark. It is determined that the image is not dark if the gain of the amplifier circuit (AGC) in the focus detection circuit (AFS) 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 <#745>, <#71
5) The subject speed detected in the past two times (6th
It is determined that the directions (obtained from the distance measurement results of <C> and <D> in the figure and those obtained from the distance measurement results of <D> and <E>) 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 according to this "moving object detection type I", there is another condition that the object does not enter the in-focus zone. The flow will be explained using FIG. 9.

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 "less than 3n, <
#930>, set the focusing zone to [80 μm] (distance measurement of <A>, <B>, and <C> in Figure 6).
[μm], <Dn, <E> distance measurement [200 μm]). Therefore, in continuous AF, the focus zone is usually [200 μm]. And <#940
Defocus amount [DF] which is the distance measurement result at > and <69
20> or <1930>, and if in focus, proceed to <#520>; if out of focus, proceed to <#520>.
Proceed to 516>.

That is, the above-mentioned value [80 μm] or [200 μm] becomes the setting value for focus determination.

FIG. 8 shows "moving object determination type (■)". first,
Defocus i [DF
] is assumed to have been cleared. Then, as a result of the determination in <#510>, when the flow after focusing (<#524>~) is entered, the defocus amount [DF (this month and [DF (sum) ) and save it to [DF (sum).<#80
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 (<#590>).

Next, in <#810>, a second determination counter [1] that determines how many times the four consecutive distance measurements have been performed is counted up. Note that both these counters [β] and [m] are
It is assumed that the value is cleared when the photometry switch (Sl) is closed. Further, in <1815>, only the first determination counter [m] is cleared.

<#820> calculates the sum of the four defocus amounts [DF(
Divide the average amount of defocus by 4.
] Find. In <#825>, this average defocus i
It is determined whether the first value after focusing of [DF (flat)] (hereinafter referred to as base defocus amount) [DF, ] is stored in memory using a memory flag to be described later. If the base defocus amount [DF,] is in the memory, proceed to <#840>; if not, go to <#830> to calculate the first average defocus amount [DF,]. ] as ], and <#835
> sets the memory flag (used in <#825>).

In <#840>, the average defocus amount [DF (average)] obtained in <#820) is stored in the memory [DF, ], and the four memories i: DFt], [DF! ]
.

Shift the data in [DF2] and [DFl] in order.

Therefore, the latest average defocus amount [Ko (Hei)] is always stored in the memory [DF4].

In <#845>, 1850>, and <#855>, a 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,
<#856> The magnification [1
/15], in addition, <#85
5>, compare the latest average defocus amount [DF, 3 and base defocus amount [DF,], and if it changes by more than [3ooμm] toward the distance, both <#
865> sets the AF flock flag and returns to the main routine (<3590>).

If the AF flock flag is not set, <#86
t)) If it is determined that the latest average defocus amount [DF, ] has moved toward the object by more than [400 μm], the object speed [V] is determined in <#890> without going through the subsequent moving object determination flow. Set it to [0.25mm/s'], which is the minimum speed for maintaining (moving object mode), and <#53
Proceed to 4>.

On the other hand, in other cases, the focal length of the photographic lens is determined in <#864> and <#866>, and <#875>
Switch the motion detection level from . If it is determined in <#864> that the focal length [f] is smaller than [50mm], the determination level [Cn] is set to [100μm] in <#867>.
and the focal length [[] is [2200mm] with <1866>
If it is determined that it is smaller, the determination level [Cn] is set to [150 μm] and the focal length [f] is set to [20 μm] in <#868>.
If it is determined that it exceeds [0 mm], the determination level [Cn] is set to [200 μml] in <#869>. This judgment level [Cnl is the average defocus amount [D
F (flat)] is used to determine the difference between two values.

Note that the switching of the moving object determination level [Cn] executed 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 determination level [Cn] is performed by changing the focal length [f] corresponding to the amount of defocus on the film and the photographing magnification [
β] and [f·β] as the 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 [Cn] is set to [100 μm].<#867'
>If the product [f・β is greater than or equal to "5" and less than "20", set the moving object detection level [Cn] to [150 μm]<#8
68'>, if the product [f・β] is "20" or more, set the moving object determination level [Cn] to [200 μm].
>, after setting each, proceed to <f1870>.

In <tt'a7o>, it is determined how many times four consecutive distance measurements have been performed, that is, whether the average defocus amount [DF (flat)] obtained for each four consecutive distance measurements has reached four. If there are four or more, the moving object determination is performed from <#875>. This moving object determination is performed using
．． 5.Cn] The object is determined to be a moving object if all three conditions are satisfied. Here, the reason why the determination level is [1,5·Cn] 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], [DF,] and the time between these two distance measurements to find the subject speed [■1], and similarly calculate the two average defocus amounts [DF,], [D] in <#897>.
F2] and the time between these two distance measurements to find the subject speed [v2], and <1899> these two subject speeds [Vl].

After calculating the average speed of [V2] (■・(V+ +V2)/2) to find the average subject speed [V], <1534
Go 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. 10, 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 that passes through the total reflection sub-mirror (SM) and reaches the focus detection optical system (AO) is reflected elsewhere when the mirror-up is started under exposure control. 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 shift 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 compensated for by driving the lens during mirror up (hereinafter this operation is referred to as focus compensation). (referred to as "drive during 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 following four consecutive distance measurements <D>, <E>, <F>, and <G> determine that the subject is a moving object, and the timing of <T> Enter (moving object mode). When entering (moving object mode), each calculation ends at <t++> and <t, 2>.

<1. >, <1+<> controls the movement of the photographing lens so that the defocus amount becomes "0". For example, if an interruption occurs between timing <tt3> and timing <ti4> due to closing of the release switch (S2), mirror-up will start at the next focusing timing <jz>. 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 I", in which the photometry switch (Sl) and release switch (Sl) are used from the beginning.
2) is a closed state. Note that the operation is the same as shown in the figure, regardless of the timing, until the release switch (S2) is closed or <F> distance measurement 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, □ mirror-up driving is performed, 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.

With this method, even if the subject is too small to enter (moving object mode), you will not miss a photo opportunity (and eliminate release lag due to out-of-focus. In other words, you can release the camera with the focus zone widened. There are, but
The out-of-focus that may occur due to 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) (
<#855>) Both are AF flocks. If the AF is locked, 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 m5l, there is a limit to the amount of drive during the mirror-up. What can be driven during this (170ms) is:
During actual exposure, it is necessary to keep the photographing lens in a stopped state, so the lens is driven while braking, so the pulse count for driving the lens is 40 pulses, which is less than in the case of normal full drive.

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 drive amount exceeds this [40 pulses], 1. Delay the start of mirror up by [40m5],
During this time, the lens is driven. We also set a limit on the drive amount when driving the lens before the release, so as not to lengthen the release time lag (only an increase of [40m5]), but unlike the drive during mirror up, full drive is possible, so the drive amount 70 pulses are secured so that the lens can be driven for a total of 110 pulses. As a result, when 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 when the front-back conversion coefficient [K] is large, it is possible to secure a lens movement amount of [100 μm].
] can be secured, which can be said to be a sufficient value 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 without entering (moving object mode). (See Figure 13). In this case and in the case of continuous AF, driving is performed during mirror up without performing moving object correction (unnecessary in the method of this embodiment). The amount of drive at this time is calculated from the distance measurement results just before the mirror is raised. 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 opening 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. In other words, if the defocus amount is less than the side setting value [70 μm], it is within the focus zone, and if the defocus amount is more than [200 μm], the camera will be shaken, and the defocus amount will be [70 to 200 μm]. In this case, it is determined that the subject has moved.

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 It is preferable to drive the mirror while it is up using the average defocus amount (DFi) obtained from the distance measurement results of <I> (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 the mirror aperture (line (iii) in FIG. 14). Furthermore, A
If we assume that the camera is shaken slightly by setting FO = (a shake of the camera that cannot be detected with <#855>), the distance measurement will be performed after [about 0.8 seconds] has passed after confirming focus. Defocus amount obtained from the results of (in Fig. 14, the average defocus amount N obtained from the distance measurement results of <G>)
[DFg] ) is preferably used to drive the mirror during mirror 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 fine-grained control, it is preferable to switch which distance measurement result to use to drive the mirror while it is up, depending on the time from focusing to opening the release switch (S2). . As mentioned earlier, the time it takes to shake the camera after focusing is [0
, 8 seconds or [1 second], so by the time of distance measurement at <G>, which is performed 0.8 seconds after focusing, <t, I> in Figure 14 If an interrupt is generated by opening the release switch (S2) at the timing of , 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 performed at a timing of [0.8 seconds] after focusing, an interrupt is generated by closing the release switch (S2) at a timing of <t4°> in Fig. 14. For example, the average defocus amount [DPd] 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 the 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 <11502> (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. 5, and this flow is passed when the judgment in <#514> is out of focus. 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> ) to 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. If this corresponds to the Apex digital signal [Bv], it becomes [-1]
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 (<#59Q>).

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, <11504
> 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 lock is activated, the process proceeds to <#1538> without driving the mirror up as shown in Table 1.

If AF rotation is not in progress, it is then determined in <#1508> whether or not continuous AF is in progress.

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 current defocus amount [DF (current)] in the memory for driving during mirror up [DFmE]. This defocus amount [
DF (now)] is the defocus amount at the time when focus was determined before entering this flow, and is not the average defocus amount.

If it is determined in <#1508> that continuous AF is not used, then in <#1510> it is determined whether the base defocus amount [DF0] is stored. If the base defocus amount [DF,] is not stored, the process also proceeds to <11514>. An example of this is
Before focusing, press the metering switch (Sl) and release switch (
S2) are both closed (hereinafter referred to as release start before focusing), and the moving object determination routine of FIG. 8 is not passed, so the base defocus amount [DF,
]. That is, even when the release is started before focusing, the defocus amount [OF (now)] at the time of focusing judgment is used to drive the mirror while it is up. Also, even during the moving object determination routine, if the initial average defocus amount cannot be calculated, the <#1510> determination will be made in the same manner.
514. ＞Proceed to ＞.

On the other hand, if an interruption occurs due to opening of the release switch (S2) during the moving object determination, the process proceeds to <#15]-2>. In <#1512>, the average defocus amount [
DF (flat)] is the drive memory [DFmE
Set to . 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. Figure 16 (
Some examples are shown in (a) to (e).

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

Figure 16 (c) shows the case of a camera designed for portrait photography, and when [0.8 seconds] have elapsed since focus, <G
The focusing average defocus amount [D
PG] to the drive memory [DFmE. Note that when using this flow, the flow shown in Figure 20 should be placed between <#870> and <#875> in Figure 8 to set the average defocus amount [DFG] after focusing. is necessary.

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

Figure 16 (:) assumes a versatile camera or a beginner's camera, and measures the time from focusing to the current timing, that is, the closing timing of the release switch (S2), using <#1610>. [t3] and <#1612
> 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 <#1614> determines the latest average defocus amount. [
DP,] is set in the drive memory [DFmE,
If it is longer than [1 second], it is determined that the camera is being swung midway, and in <#1616>, the base defocus amount [DF
, ] in the drive memory [DFmE.

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 lock will be determined as 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 (:), 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 If the average defocus i after focusing [DFG] is stored, it is assumed that more than [0.8 seconds] have passed after focusing.
#1622> sets the base defocus i [DFo] in the driving memory [DFm], but if the average defocus i [DFG] after focusing is not stored,
For one-shot AF or as focus compensation for a moving 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 memo January C (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 a camera, memory IC (E2FROM)
If you write "1" in the specified address of Figure 16 (a)
If "2" is written, the flow shown in FIG. 16 (b) may be selected. Similarly, when replacing an IC card, an I
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 (b) will be selected. good.

Returning to FIG. 15 and continuing the explanation, the drive memory [D
After any of the average defocus amounts described above is set in Fm], in <#1516> and <#1518>,
Using the lens drive amount data in the drive memory [DFm], a zone is determined as to whether mirror up drive is possible or not.
When the lens drive amount is [70μm≦DFm<200μm], in order to drive during mirror up <#1520
＞Proceed to ＞.

<#1516> indicates that the lens drive amount is the side setting value [70
μm], the mirror-up drive is not performed and the process returns to the main routine. That is, it is thought that the subject that comes to this step <#1516> 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, in <#1518>, the lens drive amount is [200um
If it is determined that the value is 1 or more, similarly, the mirror-up drive is not performed and the process returns to the main routine. In other words, if the subject is moving fast, use <#1540> or <#1.
514>, so only subjects with slow moving speed can be photographed.
#1518>, and the movement speed is slow, so the maximum amount of drive during mirror up is [200
This is because a value of less than [μm] 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.

When branching to <#1514> in the τ direction, it is completely unclear whether the subject is a stationary subject or a moving subject, and therefore the process proceeds to <#1520> on the assumption that the mirror is being driven while the mirror is up.

If it is determined in <11504> that the mode is (moving object mode), the process proceeds to <#1540>, and the current defocus amount is calculated from the start of integration by the light receiving circuit (CCD) for the currently held defocus amount [DF (now)]. In other words, the release switch (S
2) The time until the closing timing is measured and set as [tl]. In <#1542>, add the mirror-up time lag [70m5] to this time [t1] to obtain [b], and in <#1544> add the moving object speed [V] calculated during (moving object mode) and this time. Multiply by the time [tzl to find the amount of focus deviation [ΔDF] due to the movement of the subject during the time lag from integration to exposure. (referred to as the amount of motion correction).

Subsequently, in <#1546), 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,
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+1/X]
think of. Considering the assumed moving speed of the subject, the variable [X] is set to [3~5j as an experimental value].
The results show that the range of .
), the variable [xJ is set to [4] and 1.
7. Multiply the moving object correction amount [ΔDF] 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 the coefficient of 4].

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 [AVo], the open F value [A
If Vo] 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
Since the error becomes large, the moving object correction amount [ΔDF] is multiplied by the coefficient l:, 1.2] in <#1806> to compensate for the lack of correction amount.

After performing K value correction, in <#1554>, the moving object correction amount [ΔD
F] is added and stored in the drive memory [DFml, then proceed to <#1520>.

<#1524>, <#1518>, <#155
In <#1520>, which proceed from 4>, the conversion coefficient of the photographing lens [[
K] and the drive pulse counter for lens drive [E
CNT]. In <#1522>, the value of the drive pulse counter [ECNT] is "4", which is the maximum number of pulses that can be driven in a limited time while the mirror is up.
Check whether it is larger than 0''. 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 <11522>, 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 1, which is the sum of "70", the maximum number of pulses for driving before release, and "40", the maximum number of pulses for driving during mirror up.
It is determined whether the value is greater than 10". If it is determined that it is greater than 110, the pre-release drive is set to the maximum [
In order to perform 70 pulses, the pre-release drive pulse counter [EECNT] is set to "70" in <#152B>. Also, in <#1524>, drive pulse counter [E
CNT] is smaller than "110", the value obtained by subtracting "40" from the value of the drive pulse counter [ECNT] in <#1526> is set to the pre-release drive counter [ECNT].
EECNT].

Next, at <#1530>, the pre-release lens drive is started, and at <#1532>, the pre-release drive pulse counter [
EECNT] waits until it becomes "0". The maximum driving time of this pre-release lens driving is approximately 40 m5l, and does not significantly increase the time lag. <#1534
>, the drive pulse counter [ECNT] is set to "40" so that the remaining lens drive is performed while the mirror is up, lens drive is started at <#L536>, and the process returns to the main routine.

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

When this subroutine is called, first <#1724
> to start the mirror up, and <at726> to start the aperture operation of the photographic lens. Then (moving body mote)
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 30:>, press <117
32>, wait until [70 m5] has elapsed from the start of mirror up. That is, the mirror-up and aperture operation end at [70 m5]. When the mirror up, lens drive during mirror up, and aperture operation are all completed, the exposure operation starts from <#1.734>.

＜#1734＞ to run the front curtain of the shutter curtain, and ＜#1
At step 736>, the process waits for the exposure time determined by the calculation at step <#430> of the main routine, and at step <#1738>, the rear curtain of the shutter is run to complete the exposure. Then, return to the main routine.

Above, we have explained the sea fence of camera operations, but the microcomputer (μC) that performs these operations uses focus discrimination to permit release operation when the absolute value of the detected deviation by the focus detection means is less than a set value. The microcomputer (μC) is configured to set the sub-set value such that the absolute value of the detection deviation by the focus detection means at the time when the release activation signal is output is smaller than the set value for focus determination. It constitutes a focus adjustment control means that prohibits the operation of the focus adjustment means in the following cases.

[Another example]

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

<1> The reference values for various judgments that have been made to judge the condition of the subject and the intention of the photographer can be changed arbitrarily.

<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 object was moving at a high speed, the driving amount was corrected during mirror-up driving, but this may be omitted.

<4> In the previous embodiment, an example is taken in which the photographing lens is configured to be detachable from the camera body, and lens information specific to the photographing lens is obtained from the lens circuit (LEC) attached to the photographing lens. Although a configuration has been described in which a camera is configured to input the following information, the present invention can also 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, in the camera according to the present invention, when the release activation signal is output after the camera is in focus and the release operation is permitted, Focus adjustment is performed only when the deviation exceeds the setting value that is smaller than the setting value for focus judgment, so for fast-moving subjects, focus adjustment operation with good tracking performance is performed. While still being able to take pictures of subjects with almost no movement, it is possible to perform focus adjustment operations within a range that does not cause out-of-focus and less discomfort to the photographer.
Overall, it has become possible to provide a camera that can perform focus adjustment operations that are appropriate for the subject.

[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, Figure 16 C4) =(
e) - Figures 17 to 21 are flowcharts showing camera operations, Figures 6 (a) and (b) are schematic diagrams showing sea fences for focus detection operations, and Figures 10 (a) to c) 1 is a schematic diagram showing the relationship between the movement of the subject and the operation of the camera, and FIGS. 11 to 14 are time charts of focus adjustment operations, respectively. (TL)・・・Photography lens,

Claims (1)

[Claims] a focus detection means for detecting a deviation from a focus position of a photographing lens with respect to a subject; a focus determination means for permitting a release operation when the absolute value of the detected deviation by the focus detection means is less than or equal to a set value; In a camera equipped with a focus adjustment means for moving the photographing lens toward the in-focus position by a drive amount based on a detection deviation by the focus detection means until the shutter starts operating, A camera provided with a focus adjustment control means for prohibiting the operation of the focus adjustment means when the absolute value of the deviation detected by the focus detection means is less than or equal to a sub-set value smaller than the set value.