JPH0277051A - Camera - Google Patents

Abstract

PURPOSE:To perform an autofocusing action in an appropriate focusing state in accordance with the state of an object and a photographer's intention by providing a preferential switching means for switching to any focusing state preferentially to the actuation of a focusing state switching means. CONSTITUTION:A microcomputer muC constitutes a starting detection means, a magnification discrimination means for judging photographing magnification and the focusing state switching means for switching the focusing state for a moving body where the movement of a photographic lens by a focusing means is allowed during the retreating action of a mirror from the image-formation optical path by a mirror advancing and retreating control means and the focusing state for a still body where the movement of the lens is inhibited during the retreating action. The microcomputer muC and an IC card for forcibly obtaining one-shot AF constitutes the preferential switching means for switching to any focusing state out of the focusing state for the still body and the focusing state for the moving body preferentially to the actuation of the focusing state switching means. Thus, there is no possibility of the forgetfulness of an operation, misoperation or malfunction and a desirable photograph in which focusing is sharp can be surely obtained.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a camera capable of automatic focusing operation. More specifically, it includes a mirror extension/retraction control means for moving a mirror back and forth for reflecting a light beam from a subject onto a finder optical system with respect to an imaging optical path of a photographic lens onto a film; a focus detecting means for calculating a deviation from a focus position; a focus adjusting means for moving the photographing lens to the in-focus position based on the detected deviation by the focus detecting means; and a movement of the photographing lens by the focus adjusting means. focus adjustment state switching means for switching between a moving object focus adjustment state that is permitted during the retraction operation of the mirror from the imaging optical path by the mirror exit/retraction control means and a stationary object focus adjustment state that is prohibited during the retraction operation; The present invention relates to a camera equipped with the following. [Prior Art] Conventionally, in the above-mentioned camera, a dedicated operating tool is provided for switching between a focusing adjustment state for moving objects and a focusing adjustment state for stationary objects, and the switching between these two states is determined by the photographer based on the shooting conditions. It was configured such that the operation can be performed by manually operating the operating tool based on the results obtained. [Problems to be Solved by the Invention] However, in the above-mentioned conventional camera, switching between the two focus adjustment states was performed manually by the photographer. This may result in a focus adjustment state that is different from the focus adjustment state intended by the photographer. Therefore, when attempting to photograph a moving subject, the automatic focus adjustment operation with poor tracking performance may be performed due to the focus adjustment state for a stationary object, resulting in a photograph that is out of focus. Therefore, it is conceivable that the camera itself could detect the state of the subject and automatically switch between the two focus adjustment states based on the results, thereby eliminating the need for the photographer's operation.
At that time, data such as the rate of change of the detected deviation from the in-focus position by the focus detection means (i.e., the speed change of the subject) and the direction of movement of the subject are used as criteria for automatically switching the focus adjustment state. It turns out. However,
Judgments based on these data do not necessarily accurately capture the state of the subject. In other words, if the subject is stationary and you move the camera to change the composition while maintaining focus after focusing (this is generally referred to as focus lock), the rate of change in detection deviation is large and the subject moves. It is judged that. Therefore, when trying to take a picture using the focus lock described above, the focus will be adjusted for a moving subject for a still subject, and by changing the composition, the subject will be located in the shooting range corresponding to the focus detection area. There is also the possibility that the focus adjustment operation is performed on another object, resulting in a completely out-of-focus photograph. SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to provide a camera that can accurately perform an automatic focus adjustment operation in an appropriate focus adjustment state depending on the condition of the subject and the intention of the photographer. [Means for Solving the Problems] A characteristic configuration of the camera according to the present invention includes a priority switching means that is attached to the camera body and switches to any of the focus adjustment states with priority over the operation of the focus adjustment state switching means. This is because it was established. This priority switching means includes, for example, an IC card that is removably attached to the camera body. [Function] In other words, for example, the priority switching means such as an IC card controls the operation of the camera while it is attached to the camera, and the focus adjustment state switching means is configured to prevent the photographer from forgetting to operate it or erroneously operating it due to contact, etc. Even if a different focus adjustment state than intended is set by the camera's automatic switching operation, the focus adjustment state is switched to the desired focus adjustment state with priority over that setting. Therefore, basically, the focus adjustment state can be switched between the moving object focus adjustment state, which allows focus adjustment with good tracking performance for moving objects, and the still object focus adjustment state, which allows shooting with focus lock for stationary objects. Even if the camera is equipped with a switching operation tool that is flexible but requires manual operation, which can easily lead to forgetting or making mistakes, it is also possible to detect the state of the subject and automatically switch the camera based on the results. Even in a camera that switches between two focus adjustment states, it is possible to reliably switch to the focus adjustment state appropriate for the subject to be photographed, giving priority to the original switching. [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 controls the sequence of the entire camera and performs 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 (COD) 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 (JT) receives the integration end signal (SP'
) and hold its 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.
y,] 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. (IENC) is the encoder and the focus adjustment motor (
The amount of rotation of the AF motor (M) (hereinafter abbreviated as AF motor) is detected and output as a pulse signal (pulse output for a predetermined amount of rotation of the motor (M)) to the lens control circuit (LECON), which will be described later. . The lens control circuit (LECON) is
The motor rotation amount (number) signal and motor control (speed and direction) signal from the microcomputer (μC) are input, and based on these, the AF motor (M-) is driven, and the signal from the encoder (ENC) is input. Input the pulse signal and send the predetermined amount (
It also detects whether the AF motor (M) has rotated by a certain amount (motor rotation amount), and also performs stop control of the AF motor (M). The microcomputer (μC) has an internal counter for knowing the lens position, and uses an internal command to cause the counter to count up or count down in response to the input of a pulse signal from the encoder (ENC). conduct. 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) is

[The card circuit of the C card (not shown) transfers switch switching information from the outside from the memory inside the card to the 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. (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 pressing operation subsequent to the first pressing operation on the release button, and a photographing operation is performed by closing this release switch (S2). (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 (82FROM) is an electrically erasable memory that retains its contents even without power supply. This memory IC (E2FROM) 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 FIG. 2, (TLI) and (TL2) are lenses constituting the photographing lens, and both lenses (TL,). (TL2) are the distances (PZI)l (Pzt) and (PZI
<PZ2) (hereinafter, this distance will be referred to as the injection distance). And the above planned imaging plane (FP)
A field mask (FM) is placed near the FM. 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. )- are provided. Each rectangular opening (E) of the above field mask (FM)
The light beams from the subject that have passed through o), (Eot), and (Eoz) are sent to separate condenser lenses (Lo). (Lot), (Lot) (hereinafter referred to as field mask (FM)
The first condenser lens (Lo), the second condenser lens (Lot), and the third condenser lens (Log
). ), respectively, and are focused. The above-mentioned condenser lens (Lo), (Log),
Behind (Lo2), an aperture mask (AM) and a re-imaging lens plate (L) are arranged. The reimaging lens plate (
L) is a re-imaging lens pair (
Ll), (L2), and pairs of re-imaging lenses (L3), (L4) and (L5), (Ll) arranged vertically on both sides, respectively. The re-imaging lenses (Ll) to (Ll) are all plano-convex lenses with the same radius of curvature. (Hereinafter, the field mask (F
M) rectangular openings (Eo), (Eot), (EO
2), the central reimaging lens pair (Ll), (L
2) as the first re-imaging lens pair and the re-imaging lens pairs on both sides (L
3). (L, ), (L5), and (Ll) 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 (Lll), the diaphragm opening (A1)
- (A6) are 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), (Pot), (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).
t), (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), (Pot), and (PO2) are arranged in the same direction. The CCD line sensors (Po), (POI), and (PO2) are the first and second line sensors, respectively. 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), (Pop) of the field mask (FM). (LO2), the first CCD line sensor (Po
), a second CCD line sensor (Po, ), 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), (LOo). (LO2)・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 (Eor) and enters the second condenser lens (Lot). This optical axis distance measuring light beam is bent and focused toward the optical axis (Op) by the second condenser lens (Lot), and is focused at the second aperture openings (A3) and (A3) of the aperture mask (AM). , ) to the second re-imaging lens pair (L, (
Ll). a second re-imaging lens pair (L3);
The optical axis distance measuring light beam incident on (Ll) is
The images are focused onto the second CCD line sensor (Pa 1) by the second re-imaging lens pair (L3) and (Ll), and a pair of images are re-formed in the vertical direction on the second CCD line sensor (Pop). be done. Similarly, the optical axis ranging ray bundle including the chief rays (i5) and (zs) enters the field mask (FM) so as to be separated from the optical axis (Op) at the above-described predetermined angle. 3 rectangular apertures (Eoz), a third condenser lens (LO2), and a third aperture aperture (Aa) of the aperture mask (AM). (A6) and third re-imaging lens pair (L6), (L6)
The light is then 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 chief ray (j! +), D'2) and the optical axis (0, p) of the photographing lens is Optical axis (Op)
The upper first rectangular opening (Bo), the 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 (Ll), (L2) to the first CCD. The light is focused onto the line sensor (Po), and a pair of images are re-imaged in the left and right direction on this first CCD line sensor (Po). Then, the CCD line sensor (Pa), (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 the 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 in 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, a rectangular frame (AP) indicated by a dotted line is displayed to indicate to the photographer the photographing area in which 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 <1400>.
l) is closed, and the photometric switch (S
l) is closed <#400. - Loop #405>. In <1405>, the main switch (SM)
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 amount of lens drive, and the open F value (Av value) [Avo] of the photographic lens. <#415> inputs the film ISO setting data [Svl] from the film sensitivity reading circuit (130), and
20>, a photometric operation is performed and photometric data [Bv] is input from the photometric circuit (LMC). <#425> calls the subroutine <<AP) that performs automatic focus adjustment operation, but
Details will be described later. Perform exposure calculation in <#430> and determine shutter speed [Tv] and aperture value [
Av] is calculated. Next, it is determined in <#435> whether the release switch (S2) is closed, and if it is closed, <#44
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 <#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, the film is advanced in <#40>.
0>Help. FIG. 5 shows the general flow of the subroutine (AP) called in <#425>. When this subroutine is called, first
Integration is performed by the light receiving circuit (CCD) of the focus detection circuit (AFS) at >, and the pixel data is AD converted and input at <#502>. Using this pixel data <#504>
Find the amount of focus shift (defocus amount). Also, <
#502>, the card information from the card circuit ((1, D) 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. 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 subject is a moving object, so be sure to
Move to f1508>. Here, Continuous AF
We are determining whether or not. Continuous is <#502> and I was created manually.
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. <8514>
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>
> displays the focus (line display on the display section (Dfa) shown in Figure 3) and also displays the release permission flag (Figure 4 <#4).
40>). On the other hand, if <f1514> is not within the focus zone, <#
516>, it is determined whether the lens has been driven three times or more,
If it is three or more times, moving object determination is performed using the past three defocus amounts in <#518>. If it is determined in <9518> that the object is not a moving object, and if it is determined in <#516> that the object has not been driven three or more times, the lens for focus adjustment is driven in <#540> and the process returns to the main routine. Return and loop to the next distance measurement from <#50Q>. 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, which are the results of the four distance measurements, are averaged to obtain the average defocus amount [DFxl]. Then, in <#528>, 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>, <15
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
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 <#534>. Also, if it is determined that the object is a moving object in <#51B>, 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" and "moving object determination type (2)." 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, use <#5313> to display the moving object (LC 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 <#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) to set the continuous flag (continuous mode).
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 the correction may be made in the opposite direction for the back and forth movement of a moving object.If the subject moves randomly back and forth, simple continuous A'F has better tracking ability. Because it's good. 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. approximately 1.3m in film surface terms.
[m/s] or higher, it can be detected as a 'moving object detection type.' 1. Drive the lens with the second distance measurement <A> and <B>,
Moving object detection begins after focus confirmation distance measurement <C>. 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 distance measurement of <B> does not yet enter the in-focus zone due to errors in the conversion coefficient [K] 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). 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> ). Further, 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>, <D3>, 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>
, <Fl>~<F4>. When the average defocus amount [DFx] is determined in each of the four distance measurements from <G1> 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 E" and "moving object detection type II". Corresponding to the flowchart in Figure 5 above, <#5
16> and <#518> are based on "moving object detection type I", and <#524> to <#532> are based on "moving object detection type ■". In the “motion detection type ■” shown in Figure 7, first <#71
0>, it is determined whether [LCNT] is "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). Subsequently, if the drive counter is "3" at <1720>, the process exits to <#750>. If the drive counter is "4" in <#720> (distance measurement of <D> and <IE> in FIG. 6), a moving object determination is performed. 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 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 <1745>, <#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 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 greater than or equal to "3", 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).
[200 μm] with distance measurement of μm, <D>, <E>)
. 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,
Defocus i [DF
] It is assumed that the sum memory [DF(sum)] is cleared. Then, as a result of the determination in <1510>, when the flow after focusing (<#524>~) is entered, the defocus amount [DF (current)] obtained in the current distance measurement and [DF
(sum)] and save to [DF(sum). <#
At <805>, it is determined whether or not the distance measurement has been performed four times in a row. If the distance measurement has not been performed four times, the process proceeds to <#807> and the first determination counter [m] is counted up. and 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 [n] and [m]
is assumed to be cleared when the photometry switch (Sl) is closed. Further, in <#815>, only the first determination counter [m] is cleared. <#820> calculates the sum of the four defocus amounts [DF(
Divide the sum) by 4 to get the average defocus amount [Kan (Taira)
] Find. In <1825>, it is determined whether or not the first value after focusing (hereinafter referred to as the base defocus amount) [DF,] of this average defocus amount [Ko (Taira)] is stored in the memory, which will be described later. Determine using 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,] Sesera as <#835>
Set the memory flag (used in <#825>) with . In <8840>, the average defocus amount [DF (average)] obtained in <#820> is stored in the memory [DF,], and four memories [DF+], rDF3] are stored.
. Shift the data in [DF2] and IDFI] 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
If the latest average defocus amount [DF4] and the base defocus amount [DF,] have changed by more than [300 μm] toward the distance in <#8>, both
65> 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 [DF,] has moved toward the approaching object by more than [400 μm], the object speed [V] is determined by <1890> without going 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 it is determined that the focal length [f] is smaller than [50 mm] in <1864>,
If the determination level [Cnl is set to [100 μm] in <1867>, and the focal length [f] is determined to be smaller than [200 mm] in <#866>, the determination level [Cnl] is set to [100 μm] in <1868>.
Cnl is [150°μm], focal length [f] is [20
0 mm], the determination level [Cnl is set to [200 μm] in <1869>. This determination level [Cnl is for determining the difference between two values of the average defocus amount [Ko (flat)]. Note that the switching of the moving object determination level [Cnl executed in <#864> to <#869> can also be performed by another method. An example thereof is shown in FIG. In this example, the moving object detection level [Cnl] is switched between the focal length [f], which corresponds to the amount of defocus on the film, and the imaging magnification [Cnl].
β] and [f·β] as the criterion for determination. That is, as a result of the determination at <#864"> and <#865°>, if the product [f・β] is smaller than "5", the moving object determination level [Cnl is set to [100 μm] <#867°>,
If the product [f・β] is “5” or more and less than “20”, the moving object determination level [Cnl is set to [150 μm]<#868
If the product [f·β] is equal to or greater than '20', the moving object determination level [Cnl] is set to [200 μm] <#869'>, and the process then proceeds to <#870>. 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 <1875>. This moving object determination is based on [DF3-DF, ≧Cn] and [DF
, -DF2≧Cn and [DF, TDF,≧1.5・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 [V+], and similarly calculate the two average defocus amounts [DF,], [DF] in <#897>.
2] and the time between these two distance measurements to find the subject speed [■2], and <3899> these two subject speeds [Vl]. After performing the average calculation of [■2] (■·(Vl+V2)/2) to obtain the average subject speed [V], the process proceeds to <#534>. 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 Figure 1O, film (F
) is a photographic lens (TL
), the ray flux passes through the finder optical system (F
l) an 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 end point <t++>, '<t, □>. Defocus amount is “0” at <t'3> and <t+4>
Control the movement of the photographic lens so that For example, if an interruption occurs between the timing <tea> and the timing <ti+> due to opening of the release switch (S2), the mirror up starts at the next focusing timing <j+4>. 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 ■", 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. ``Moving object detection type■'' is a fast-moving subject, and distance measurement <
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, the mirror is driven while the mirror is up, and the photographing lens is moved so that the deformation force becomes "0" at the 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 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. Driving while the mirror is up during this AF clock will result in a poor photograph, so the mirror is not driven 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 of time that can be driven during this [70m5] is less than in the case of normal full drive because the photographing lens needs to be stopped during actual exposure, so the lens is driven while braking. The driving pulse count is [40 pulses]. If this value is a photographic lens with a longer focal length than a standard lens [50/1.7], the lens will move more than [200 μm], so the in-focus zone [ Even if the photographic lens is stopped at the edge of [200μm], the lens can be driven by this value. If the required lens drive amount exceeds this [40 pulses], delay the start of mirror up by [40m5l] and move the lens during this time. We 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]).
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 can 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 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 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. In other words, the defocus amount 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 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 while the mirror is up (
(line (iii) in FIG. 14). Furthermore, AF
If we assume that the camera is slightly shaken by flocting (a camera shake that cannot be detected with <#855>), then the distance measurement result will be obtained after [about 0.8 seconds] has passed after focusing has been confirmed. Defocus amount determined from (<G in Fig. 14)
The average amount of defust debris [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 performed at a timing of [0.8 seconds] after focusing, an interrupt is generated by closing the release switch (S2) at a timing of <14□> in Fig. 14. For example, 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 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
In >, the card one-shot flag input in <#502> in Fig. 5 is determined, and if there is a card one-shot flag, the mirror is not driven during mirror up and <, #1538>
Proceed to. At <11538>, the drive pulse counter [ECNT] for driving the lens is set to "0", and then the process returns to the main routine. Similarly, if <#1502> is (auxiliary light AF 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 <#1902> 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 [By], 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 (<#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, <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 [DFm]. This defocus amount [D
F(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 <11508> that continuous AF is not used, then in <#1510> it is determined whether the base defocus amount [DF, ] is stored. If the base defocus amount [DF,] is not stored, the process also proceeds to <#1514>. 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 pace defocus fi [D
Therefore, it does not have [Fo]. In other words, even when the release starts before focusing, the defocus ft [
DF (now)] is used to drive the mirror up. Also,
Even in the moving object determination routine, if the first average defocus amount has not been calculated, the process similarly proceeds to <#1514> based on the determination of <#1510>. 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 <11512>. In <#1512>, the average defocus amount [D
F (Flat)] to the milli-needle speed drive harpoon [DFm]. There are various embodiments of this step <#15], 2> 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,] is set in the drive memory [DFm]. 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 [DF,].
m]. 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
FG] in the drive memory [DFm]. 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 [1] 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 ffi[DFG]. Figure 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 closing timing of the release switch (S2), is measured 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. [
While setting OF, ] in the drive memory [DFm],
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 [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 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 (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 If the average defocus amount [DPG] after focusing is stored, it is assumed that more than 0.8 seconds have passed after focusing.
1622>, the base defocus amount [DF,] is set in the drive memory [DFm], while if the average defocus amount after focusing ffi [DFG] is not stored,
For one-shot AF or as focus compensation for a moving subject, the latest average defocus amount [DF,] 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, memo January C (E2FROM)
If you write ``1'' in the specified address, the flow shown in Figure 16 (a) will be executed, and if you write ``2'' in the specified address, the flow shown in Figure 16 (a) will be executed.
Each of the flows shown in b) may be selected. Similarly, when replacing an IC card, an IC with "1" written at a predetermined address on the card circuit (CD)
If a card is installed, the flow shown in Figure 16 (a) is selected, and if an IC card labeled "2" is installed, the flow shown in Figure 16 (b) is selected. . 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], determine whether or not the mirror up drive is possible or not, and determine if the lens drive amount is [70μm≦DFm<200μm].
In this case, to drive during mirror up <#152
Proceed to 0>. If it is determined in <#1516> that the lens driving amount is less than 70 μm1, the process returns to the main routine without performing mirror-up driving. In other words, this <#l516
It is thought that the subject that comes to 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 [200μm1
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.
1518> and the movement 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, when branching to <#1514>, since it is completely unclear whether the subject is a stationary object or a moving object, the process proceeds to <#1520> on the premise that the mirror is being 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]. <#1542> Add the mirror up time lag [70m5] to this time [1+] 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 moving object correction is performed using this amount of focus shift [ΔDF], this amount of focus shift [ΔD] will be referred to as the moving object correction amount). Subsequently, in <#1546>, the sign of the moving object speed [V] is determined. In this determination, if [V>O], 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, <11
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 experimental value of the variable [X] was found to be preferably in the range of 3 to 5, and the microcomputer (μC
), 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 [ΔDF] 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 [AVo], the open F value [A
If Vo] is larger than the predetermined value [J1], that is, if the photographic lens is dark, in <#1802> the moving object correction amount [ΔKo is multiplied by a factor of [1,2], and then the conversion coefficient [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, by multiplying the moving object correction amount [ΔDF] by the coefficient [1, 2] in <#1806>,
Make up 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 <11520>. <#1524>, <#1518>, <#155
In <11520), 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 40, which is the maximum number of pulses that can be driven in a limited time while the mirror is up.
′ Checks if it is greater than ′. If it is determined that the value 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] becomes "1", which is the sum of "70", the maximum number of pulses for pre-release drive, and "off", the maximum number of pulses for drive during mirror up.
Determine whether or not the value is greater than 10". If it is determined that the value is greater than 110", the pre-release drive is set to the maximum [
70 pulses], the pre-release drive pulse counter [EECNT] is set to "70" in <#1528>. 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]. Subsequently, pre-release lens drive is started at <#'1530>, and waits until the pre-release drive pulse counter [BBCNT] reaches "0" at <#1532>. The maximum driving time of this pre-release lens driving is [approximately 40m5],
It does not significantly increase the time lag. <#153
In step 4>, the driving pulse counter [ECNT] is set to "40" so that the remaining lens driving is performed during mirror up, and in <#1536>, lens driving 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, this 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 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 <#1734>. <#
1734> to run the first curtain of the shirt curtain, and <#173
At step 6>, 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. The sea fence for camera operations has been explained above, and the microcomputer (μC) that performs these operations controls the mirror control means that moves the mirror (MM) in and out, the activation detection means that detects the activation of the release operation, and the photographic magnification. magnification determination means for determining the moving object focus adjustment state in which the movement of the photographing lens by the focus adjustment means is permitted during the retraction operation of the mirror from the imaging optical path by the mirror egress/retraction control means, and prohibition during the retraction operation. The focus adjustment state switching means is configured to switch between a focus adjustment state for a stationary object and a focus adjustment state for a stationary object.
A microcomputer (μC) that performs the processing of <#1500> and <#1502> in Figure 5 and an IC card for forcing one-shot AF to focus on a stationary object with priority over the operation of the focus adjustment state switching means. A priority switching means is configured to switch to either a focus adjustment state or a moving object focus adjustment state. [Another Embodiment] Hereinafter, other embodiments other than those described in the previous embodiments will be listed. <1> The reference values used for various judgments that are used to judge the condition of the subject or 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, if it is determined that the subject is moving at a high speed, the drive amount correction during mirror-up driving 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 [Effects of the Invention] As described above, in the camera according to the present invention, the priority switching means reliably switches to one of the focus adjustment states in priority to the operation of the focus adjustment state switching means, so that there is no need to forget or perform an operation. It is now possible to reliably obtain a desired, sharply focused photograph without the risk of mistakes or malfunctions.

[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. (and)...Taking lens, (F)...Film, (Fl)...Finder optical system, (
MM)...Kura.

Claims (1)

[Claims] a mirror advancing/retracting control means for moving a mirror back and forth for reflecting a light beam from a subject onto a finder optical system with respect to an imaging optical path of the photographing lens onto the film; a focus detecting means for calculating a deviation; a focus adjusting means for moving the photographing lens to the in-focus position based on the detected deviation by the focus detecting means; and a focus adjustment state switching means for switching between a moving object focus adjustment state that is allowed during the retraction operation of the mirror from the imaging optical path by the retraction control means and a stationary object focus adjustment state that is prohibited during the retraction operation. A camera provided with a priority switching means that is attached to a camera body and switches to one of the focus adjustment states with priority over the operation of the focus adjustment state switching means.