JP2780171B2 - Focus detection system for reflective telephoto lens and reflective telephoto lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial applications)   The present invention provides a reflective telephoto lens using a TTL phase difference detection method.
Focus detection system and reflective telephoto lens
Things. (Conventional technology)   Conventionally, the first and second portions of the exit pupil plane of an interchangeable lens are
The passed subject light is formed as first and second light images.
And determine the focus detection state based on the image interval.
TTL phase difference detection type focus detection device
It is widely used in automatic focusing devices for cameras. this
AF light used for focus detection
The position and size of the AF pupil through which the bundle passes
It is decided by design. This AF pupil is the exit pupil of the interchangeable lens
If it is inside, there will be no vignetting in the AF light beam and focus
There is no hindrance to the detection operation. However, exchange
The position and size of the exit pupil of the interchangeable lens are not fixed,
Vignetting occurs in the AF luminous flux when the lens deviates from the exit pupil
There was something. In this case, a focus detection error may occur,
There is a problem that point detection becomes impossible.   Therefore, conventionally, a pair of optical sensors for focus detection is used in combination.
Provided with several types, one type according to the open aperture value of the lens used
It has been proposed to select and use optical sensors.
(Japanese Patent Publication No. 62-6206). However, this conventional technique
The art is a big match between the exit pupil of the interchangeable lens and the AF pupil of the camera body.
Since it is not an accurate comparison of small relationships and positional relationships,
Is it possible to accurately determine the presence or absence of vignetting in AF luminous flux?
Was. Also, especially, the exit pupil is inside, like a reflective telephoto lens.
No consideration is given to cases where restrictions are imposed on the
No.   Reflective telephoto lenses are cheap and compact
The advantage is great, with a reflective telephoto lens attached to the camera body
It is also desirable to be able to perform focus detection or automatic focus adjustment
I have. A conventional reflection telephoto lens with TTL phase difference detection method A
A type that can be attached to a single-lens reflex camera with F function
Is also commercially available, but this is attached to the camera body
Is also configured to send lens information to the camera body.
And the AF function of the camera did not work. (Problems to be solved by the invention)   As described above, the method disclosed in Japanese Patent Publication No. 62-6206
In the formula, focus detection is possible according to the open aperture value of the lens used.
No, but the lens used is reflective telephoto.
In the case of a lens, the luminous flux is restricted even inside the exit pupil.
Focus on the aperture data only.
The problem that detection is not possible
There is.   The present invention has been made in view of such a point,
Its purpose is to read from a reflective telephoto lens.
Of the exit pupil diameter, exit pupil inner diameter, and exit pupil position.
The focus detection based on the data
Detection system for anti-reflection telephoto lens
To provide a telephoto lens. (Means to solve the problem)   Focus detection system for reflective telephoto lens according to the present invention
In order to achieve the above objectives,
As shown, at least the exit pupil plane of the reflective telephoto lens ML
At least one pair of light images from light beams from a pair of different regions
And an optical means 1 for forming the light image and at least receiving the light image.
Also a pair of light receiving means 2₁, 2_TwoAnd this at least one pair of light receiving
Means 2₁, 2_TwoDetect relative displacement of light image based on output
At least one focus detection means for performing focus detection by performing
Step 3 and exit pupil outer diameter read from reflective telephoto lens ML
And the diameter of the exit pupil and the data on the exit pupil position
The combination of the optical means 1 and the optical system of the reflective telephoto lens ML
The focus detecting means 3 performs optically accurate focus detection.
Determination means 4 for determining whether or not it is possible to perform focus detection
Operation permission means 5 for operating the focus detection means if possible
It comprises.   However, FIG. 1 functionally blocks the configuration of the present invention.
It is an explanatory diagram shown, and in an embodiment described later, focus detection
A part of the means 3, the determination means 4 and the operation permission means 5 are microphones.
This is realized by a computer program.   In the reflective telephoto lens according to the merged invention,
As shown in FIG. 1, a camera body having focus detecting means 3
Reflective telephoto lens ML attached to
Storage means 6 for fixedly storing the data of the camera, a camera body
Read signal input means 7 for inputting a read signal from
The data stored in the storage means 6 is captured based on the signal.
Data transmitting means 8 for sequentially transmitting the data to the camera body.
The data stored in the storage means 6 includes
Data on pupil outer diameter, exit pupil inner diameter, and exit pupil position
It is characterized by being included. (Action)   The operation of the present invention will be described with reference to FIG. Right side of Fig. 1
Focus detection system for reflective telephoto lens shown in
In addition, the optical means 1 is provided on the exit pupil plane of the reflective telephoto lens ML.
At least more than luminous flux from at least one pair of different regions
A pair of light images are formed and the light receiving means 2₁, 2_TwoReceives this light image
Light. The focus detecting means 3 includes the light receiving means 2₁, 2_TwoBased on the output of
Focus detection by detecting the relative displacement of the light image
Do. The discriminating means 4 reads from the reflection telephoto lens ML.
Data on the exit pupil outer diameter, exit pupil inner diameter, and exit pupil position
Based on the data, the optical system of the optical means 1 and the reflective telephoto lens ML
From the combination of the focus detection means 3 is an optically accurate focus.
It is determined whether detection can be performed. And dynamic
The operation permitting means 5 is a focus detecting means 3 if the focus can be detected.
Is to operate. Therefore, this reflection telephoto
Focus detection system for lenses, reflective telephoto lens ML
From the outer diameter of the exit pupil, the inner diameter of the exit pupil, and the position of the exit pupil
Limiting exit pupil inside by reading data
Optically accurate focus detection
It is possible to correctly determine whether or not it is possible.   Next, regarding the reflective telephoto lens ML shown on the left side of FIG.
In addition, the data unique to the lens is fixedly stored in the storage means 6.
Remembered. The read signal input means 7
When the read signal is input, the data sending means 8 reads the read signal.
The data stored in the storage means 6 based on the signal
Send to the body sequentially. The data stored in the storage means 6
Some of the data include the outer diameter of the exit pupil of the lens, the inner diameter of the exit pupil,
Since data on the exit pupil position is included,
What can correctly inform the body of the light passage area
It is. (Example)   Fig. 2 shows a multi-point distance measuring module installed in a single-lens reflex camera.
It is a figure which shows the schematic structure of a rule. In the figure, 11 is shooting
Lens, 12 is the main mirror, 13 is the film surface, 14 is the submirror
And 15, a focus detection optical system. 22 is located near the focal plane
Field stop, which has rectangular openings 22a, 22b, 22c.
ing. 21a, 21b, 21c are condenser lenses, 20 is a module.
Mirrors, 18a, 18b, 18c are separator lens pairs, 16a, 1
6b and 16c are CCD images placed on the focal plane 17 of the separator lens.
It is an image element row. 19 is an aperture mask, which is circular or oval
It has shaped openings 19a, 19b, 19c. In the rectangular opening 22a
Therefore, an image with a limited field of view needs the condenser lens 21a.
Pass through the field stop 19a and the separator lens pair 18a
The images are projected as two images on the CCD image sensor array 16a. this
Focuses when the image interval between the two images is a predetermined interval.
When the distance is narrower, the front pin is used.
It is determined to be the back focus. Similarly, the images of the field stops 19b and 19c are
Condenser lenses 21b, 21c and separator lens pair 18b, 1
The image is projected onto the CCD image sensor rows 16b and 16c by 8c.   FIG. 3 shows a focus detection on the optical axis z in FIG.
Optical system 15a (condenser lens 21a, separator lens pair
18a, CCD image sensor array 16a) and on the optical axis z
Focus detection optical system 15b (condenser lens 21b, separate
Combination of a pair of lator lenses 18b and a CCD image sensor array 16b)
Is extracted. Fill each focus detection frame
What is shown on the Lum equivalent plane F is the distance measurement frames A and B.
Hereinafter, A is an on-axis ranging frame, and B is an off-axis ranging frame.
Call. In addition, the distance measurement frames A and B are
The distance measurement frames projected on the object surface are A 'and B'. Shooting
On the exit pupil plane of the shadow lens 11, there is an on-axis focus detection optics.
The separator lens pair 18a in the system 15a is a condenser lens
The images projected by the zoom 21a are indicated by 11a and 11b.
Also, the separation in the off-axis focus detection optical system 15b
Lens pair 18b is projected by the condenser lens 21b.
The images shown are 11c and 11d.   FIG. 4 is a view showing the photographing at an arbitrary exit pupil position of the photographing lens.
Entering the exit pupil aperture of the shadow lens and the focus detection optical system
In general, the positional relationship of the AF luminous flux is shown.
FIG. FIGS. 5 and 6 show the parts shown in FIG.
Of the focus detection optics
FIG. 4 is a diagram for explaining AF pupil related constants determined by the following. Fifth
FIG. 3 is a view on the optical axis from the direction of arrow (x) in FIG.
This is a view of the focus detection optical system 15a, and is indicated by an arrow (y).
The same applies when viewing the focus detection optical system 15b outside the optical axis from the direction.
It looks like this. FIG. 6 shows that the optical axis is shifted from the direction of the arrow (x).
FIG. 5 is a view of the focus detection optical system 15b of FIG.   Before entering the following description, use in FIGS.
Explanation of various parameters and constants used
I do.   In FIG. 4, Pz is the exit pupil position, which is
The distance between the Lum equivalent plane F and the exit pupil plane of the given photographing lens
means.   P₀Is the outer exit pupil radius at the exit pupil position Pz.
Hereinafter, it is referred to as an exit pupil outer diameter.   ΔP₀Is the outside emission when viewed from the specified image height position
These are parameters for correcting the shape of the pupil.
Side exit pupil image height correction data (or simply abbreviated to
Correction data ”).   P₀′ Indicates that the taking lens is a reflective telephoto type,
This is the exit pupil radius for regulating the inner exit pupil.
Below, it is called the exit pupil inner diameter. Exit pupil diameter P₀And exit pupil inner diameter P₀′
Does not generally mean that they are at the same exit pupil position
However, in the following description, it is assumed that
You.   ΔP₀′ Indicates the inner projection when viewed from the specified image height position.
This is a parameter for correcting the shape of the exit pupil.
Inner exit pupil image height correction data (or abbreviated
High correction data ”). The exit pupil is usually circular
Image height on the film surface
Therefore, as shown by the broken line in FIG.
Become. ΔP₀Or ΔP₀′ Is a parameter to represent this shape change.
Parameters.   AFP is the AF luminous flux area and enters the focus detection optical system.
The passband of the F light beam is shown.   H₀Is the distance from the main optical axis z of the shooting lens in the AF luminous flux area AFP
Indicates the amount. In the case of the focus detection optical system 15a on the optical axis
Is the deviation amount H₀= 0 is set.   r₀Indicates the size of the AF luminous flux area AFP at the exit pupil position Pz.
You.   d₀Is the distance between the two AF luminous flux areas AFP at the exit pupil position Pz
Represents This distance d₀Affects the detection sensitivity of the focus detection optical system.
Is the amount that affects₀Is large, focus detection sensitivity
Is high, but shooting lenses with small exit pupil diameters cannot be used
Becomes   Δd is the amount of blur of the AF luminous flux area AFP in the focus detection optical system.
Represent.   OUT indicates that the light beam entering the focus detection optical system
Is the amount of extra pupil margin that is given by:   OUT = P₀−r₀         − ｛(H₀+ ΔP₀)²+ (D₀+ Δd / 2)²｝^1/2   Particularly, in the case of the on-axis focus detection optical system 15a,₀
= 0, ΔP₀= 0,   OUTz = P₀−r₀−d₀−Δd / 2 Becomes   IN is inside when the taking lens is a reflective telephoto type
The pupil margin is expressed by the following equation.   IN = ｛(H₀+ ΔP₀′)²+ (D₀−Δd / 2)²｝^1/2         −r₀−P₀′   In particular, in the case of the on-axis focus detection optical system 15a, H₀= 0,
ΔP₀= 0,   INz = d₀−Δd / 2−r₀−P₀′ Becomes The sign of the outer and inner pupil margins OUT and IN
The selection of the distance measurement frame and the distance measurement frame
The selection of the distance measurement area within is performed.   Next, in FIG. 5, a is the condenser lens 21a.
From the film equivalent plane F.   t is a distance between the condenser lens 21a and the separator lens 18a.
(Or the nearest aperture mask 19a)
It is separation.   Ps is the separator lens 18a (or
Image of a certain aperture mask 19a) by the condenser lens 21a
(Hereinafter referred to as the “AF pupil”) is the position where
Below, this is called the AF pupil position.   Os is a point on the optical axis at the AF pupil position Ps, and QsQs ′ is
AF pupil aperture.   AF pupil position Ps and AF pupil aperture QsQs'
Unique in design by the power of 21a and the distances a and t described above
Is decided. Therefore, from the point Os on the optical axis, the AF pupil aperture QsQ
The distances OsQs ′ and OsQs from s ′ to the farthest point Qs and the nearest point Qs ′ are
It can be regarded as a constant. Furthermore, the distance measurement on the film equivalent plane F
Frame size e and on-axis focus detection optical system 15a
The chief ray of the lens has with respect to the principal optical axis z of the taking lens
ω is also determined by design.   Incidentally, the blur amount Δ of the AF luminous flux area AFP described with reference to FIG.
d is a separation predetermined by the focus detection optical system.
Exit pupil position than the conjugate position of the lens or aperture mask
When it is far or near, Δd> 0. this thing
Will be described with reference to FIG. Separator lens 18a
Through the condenser lens 21a and through the exit pupil of the taking lens.
When the exit pupil position Pz = Ps,
Is the center point R of the separator lens 18a.₀One-dot chain coming out
Each ray shown by a line, a solid line and a dashed line has one point Rs = Rs'.
As a result, the blur amount Δd = 0. Also, shooting lens injection
When the pupil position Pz is at a point closer to the AF pupil position Ps (Pz = Pz
₁<Ps) is the center point R of the separator lens 18a.₀Get out of
The ray indicated by the solid line is point R₁And the light rays indicated by the broken lines
Is the point R₁′, The ray indicated by the dashed line
As a result, the blur amount Δd> 0. Exit pupil position of shooting lens
When Pz is at a point farther than the AF pupil position Ps (Pz = Pz_Two> P
s) includes the center point R of the separator lens 18a.₀Solid line
The ray indicated by is the point R_Two', And the ray shown by the dashed line
Point R_TwoThe light indicated by the dashed line passes through
Thus, the blur amount Δd> 0 again. Here,
Focus detection to easily show the relationship between various parameters
The AF beam control mask (aperture mask) of the optical system is circular
However, in general, there is no need to be circular.
No.   Next, in FIG. 6, θ represents an off-axis focus detection optical system 15.
The inclination of the principal ray lp at b with respect to the principal optical axis z, h is off-axis
The amount of deviation of the distance measurement frame from the main optical axis z.
Also, the CCD image sensor array 16b and the separator lens 18b (and the
Mask 19b) and condenser lens 2 in the immediate vicinity of
Since the design is determined by the geometrical arrangement of 1b,
When the design is completed with the Mera body, it becomes a unique constant.   Using the above constants, the parameters explained in Fig. 4
H₀, r₀, d₀Is expressed as follows.   First, the distance from the main optical axis z of the taking lens in the AF luminous flux area AFP
H₀Is   H₀= H- (Pz + a) tan θ It is represented by Here, the distance from the main optical axis z of the distance measuring frame is
From the condenser lens 21a to the film equivalent surface F.
, The inclination θ of the principal ray lp with respect to the principal optical axis z is
As described above, it is body information and a constant. Exit pupil position
The position Pz is lens information, and differs for each lens.   AF light flux area AFP size r at exit pupil position Pz₀Is   r₀= | OQ-OQ '| / 2 It is represented by Here, O is on the optical axis at the exit pupil position Pz.
Where Q is the AF luminous flux area AFP at the exit pupil position Pz.
The point farthest from the optical axis, Q 'is at the exit pupil position Pz
This point is closest to the optical axis of the AF light beam area AFP.   Pz = Pz₁When ≦ Ps, in FIG.   Also, Pz = Pz_Two> Ps, in FIG.   Furthermore, the distance d between the AF luminous flux area AFP₀Is It is represented by   In the above equations, OsQs, OsQs ′, Ps, e are all
It is a constant and constant. Also, Pz = Pz₁, Pz_TwoIs individual
Is a value specific to the lens.   As is clear from the above, the outer and inner pupil margins
The quantities OUT and IN are a series of body constants OsQs, OsQs ′, Ps, e
Lens information Pz, P₀, P₀', ΔP₀, ΔP₀′
expressed. Suitable for the outer and inner pupil margins OUT and IN
A sharp threshold is set, and distance measurement within the on-axis and off-axis distance measurement frames
Area selection or multiple ranging frames
In this case, it is possible to select a ranging frame. Distance measurement area
To select the frame or ranging frame, select
Calculate side and inner pupil margins OUT and IN using the above formula
And Pz and P based on the result calculated in advance.₀, P
₀′,₀,₀′ To set an appropriate threshold
Prepare a table in the camera body to select
However, in the following, we will take the latter position.
Will be explained.   First, select the ranging area in the ranging frame on the optical axis
An example is given below.   FIG. 7 shows the focus detection optical system 15a on the optical axis and AF light.
Various exit pupils P for vignetting situation₀a, P₀a ′; P₀b, P₀b ′; P₀
c, P₀c ′; P₀d, P₀Shown for taking lens with d ′
Things. Here, exit pupil P₀b, P₀b 'is the AF pupil in Fig. 5.
It is assumed that they coincide with the openings QsQs'. Film equivalent surface
Image A on F₀B₀Is the condenser lens 21a and the separator lens.
18s₁, 18a_TwoImage on the CCD image sensor array₁B₁And A_TwoB_Two
As an image. Point A on CCD image sensor array₁, B₁, A_Two, B_TwoEnter
Considering the passband of the emitted light, point A₁Light incident on is LA
1 to UA1, point B₁Light incident on LB1 to UB1, point A_TwoIncident on
Light is LA2-UA2, point B_TwoThe light incident on the
It can be seen that it has. Exit pupil that matches AF pupil aperture QsQs'
P₀b, P₀b ', of course,
Rare does not occur.   Fig. 8 shows the exit pupil P₀a, P₀a ′; P₀b, P₀b ′; P₀c, P₀c ′; P₀d,
P₀The illuminance distribution on the CCD image sensor array corresponding to d 'is shown.
You. In FIG. 8, the horizontal axis indicates the arrangement of the CCD image sensor array.
The vertical axis indicates the direction in which the elements are arranged.
Indicates the degree. The image A is stored in the right image sensor row R₁B₁Is imaged
Then, the image A is_TwoB_TwoShall form an image
You. The left image sensor array L is connected to four distance measurement areas I to IV.
The area is divided.   Exit pupil P₀b, P₀When using a shooting lens with b '
Is the outer exit pupil P₀Depending on b, the inner exit pupil P₀b ′
Therefore, the vignetting of the AF light beam does not occur, so the illuminance on the element surface
The distribution becomes a uniform distribution E. Therefore, in this case,
All ranging areas I-IV can be used.   Exit pupil P₀a, P₀When using a taking lens with a '
Is the outer exit pupil P₀By a, the light flux of UA2 and the light flux of UB1
Vignetting, the illuminance on the element surface near the optical axis z decreases.
Accordingly, the distribution J is obtained. Also, the inner exit pupil P
₀a ′ causes vignetting in the LB2 light beam and LA1 light beam
Therefore, the illuminance of the element surface far from the optical axis z also decreases, and the distribution G
become that way. Therefore, it is affected by vignetting of AF light flux
The distance measurement area that can be used without using is IV.   Exit pupil P₀c, P₀When using a shooting lens with c '
Is the outer exit pupil P₀c to UB2 and UA1
Since vignetting occurs, the illuminance on the element surface far from the optical axis z decreases.
Therefore, the distribution G is obtained. Also, the inner exit pupil P
₀c ′ causes vignetting in the luminous flux of LA2 and LB1
Therefore, the illuminance of the element surface close to the optical axis z also decreases, and the distribution J
Become like Therefore, it is not affected by vignetting of AF luminous flux
The ranging area that can be used for is IV.   Exit pupil P₀d, P₀When using a shooting lens with d '
Is the outer exit pupil P₀d to UB2 luminous flux and UA1 luminous flux
Since large vignetting occurs, the illumination of the element surface far from the optical axis z
The degree drops greatly and becomes like distribution H,
Therefore, the ranging areas I, II, and IV cannot be used. Also, inside
Exit pupil P₀Due to d ′, vignetting occurs in the luminous flux of LA2 and LB1.
, The illuminance on the element surface near the optical axis z also decreases,
It looks like a distribution J, and therefore uses the ranging area III.
There is no usable ranging area after all.   From this, tables like Tables 1 to 4 will be created
it can.   Table 1 shows the exit pupil position Pz and the exit pupil outer diameter P₀On-axis measurement from
An example of the table for selecting the distance measurement area in the distance frame is shown.
You. In Table 1, I, II, III, and IV indicate distance measurement areas.
You. × indicates that the vignetting of the illuminance distribution is large and distance measurement is impossible.
Indicates that P₀₁~ P₀₄, Pz₁~ Pz_FourIs obtained from the above equation.
This is a predetermined constant. Exit pupil P described above₀b is Pz = Ps, P₀
Applicable when b = OsQs, exit pupil P₀a is Pz_Three<Pz <Pz_Four, P₀₃
<P₀a <P₀₄In the case of, exit pupil P₀c is Pz₁<Pz <Pz_Two, P₀₁<P₀c
<P₀₂In the case of, exit pupil P₀d is Pz <Pz₁, P₀d <P₀₁In the case of
Hit. Selection of ranging area for non-reflective telephoto type
Can be performed from Table 1.   Table 2 shows the exit pupil position Pz and the exit pupil inner diameter P₀From
Of the table for selecting the ranging area in the on-axis ranging frame
Here is an example. Exit pupil P described above₀b ′ is Pz = Ps, P₀b '= OsQ
s ′, exit pupil P₀a ′ is Pz_Three<Pz <Pz_Four, P₀₃′
<P₀a '<P₀₄′, Exit pupil P₀c ′ is Pz₁<Pz <Pz_Two, P
₀₁′ <P₀c ′ <P₀₂′, Exit pupil P₀d ′ is Pz <Pz₁, P
₀d ′ <P₀₁'. Reflective telephoto field
At the predetermined exit pupil position Pz, the exit pupil outer diameter P₀From the first
Select the distance measurement area using Table 1
Diameter P₀', Select the ranging area using Table 2 and select
Ultimately determine the common ranging area of both selected
It is.   Table 3 shows the exit pupil position Pz and the modified exit pupil outer diameter.₀from
An example of the selection table of the ranging area in the off-axis ranging frame
It is. Deformed exit pupil outer diameter₀Is on the axis (or near the axis)
Exit pupil diameter P as viewed from₀And external image height correction data ΔP₀
And the body constant k partially related to the pupil position Pz,
It is approximately determined by the following equation.   ₀= P₀−k · ΔP₀                (0 ≦ k ≦ 1)   Here, in FIG. 6, the principal ray lp of the AF light beam is shifted along the optical axis z.
Is approximately Pz = Ps (AF pupil position, constant)
Then, when Pz = Ps, k = 0, which is
Indicates that the AF luminous flux does not deviate from the main optical axis z.
ΔP₀Has no effect
(See FIG. 4). Also, Pz << Ps or Pz >>
In the case of Ps, k approaches 1.   Generally, the AF luminous flux area AFP of the off-axis ranging frame is determined by the optical axis z
K varies from k = 0 to 0.8.
Parameters. The meaning of the k value itself lies outside the optical axis
The AF luminous flux area AFP of the focus detection optical system and the AF pupil position Ps are large
Exit pupil diameter P at different exit pupil positions Pz₀Margin with
ΔP when considering₀Coefficient to change the weight of
You.   Deformed exit pupil outer diameter defined in this way₀Is off-axis measurement
It is used to determine the distance measurement area only in the distance frame. That
Table 3 shows an example. Shown in Table 1
Selection of the focusing area in the on-axis ranging frame
Is that For shooting lenses with a small exit pupil position Pz,
Eye diameter₀Even if the size is large, the AF luminous flux is easy to vignetting. Also, shooting where the exit pupil position Pz deviates significantly from the AF pupil position Ps
The AF beam is also off-axis to the lens as shown in Fig. 6.
As it deviates greatly, the k value itself also increases, so AF light
This is because the bunch is easily vignetted.   Exit pupil inner diameter P for selecting off-axis ranging area₀´
Even if there is a deformed exit pupil inner diameter₀′₀'= P₀'+ K'
・ ΔP₀′ (0 ≦ k ′ ≦ 1), and₀To
₀', The same argument can be made. Table 4 shows
Exit pupil position Pz and deformed exit pupil inner diameter₀Off-axis distance measurement
It is an example of a selection table of a ranging area in a frame.   FIG. 9 is a circuit diagram of a camera system to which the present invention is applied.
is there. (DT) is a light receiving section for focus detection, which is indicated by 16 in FIG.
It has CCD image sensor rows indicated by a, 16b, and 16c. (IFC)
Is an interface circuit of the CCD image sensor row.
Controls the operation and reads out from the CCD image sensor array.
A / D conversion of the signal
And the charge storage of the CCD image sensor array
The end of the product operation is determined by the interrupt input terminal (IN) of the microcomputer (COM).
T₁). The CCD image sensor array
The charge accumulation time to the light is monitored by monitoring the brightness of the subject
It is controlled by an output of a unit (not shown).   (MOAF) is a lens drive motor for AF, (MDA)
Is a motor control circuit, and the output port of the microcomputer (COM)
To (p₀), (P₁), Forward rotation, reverse rotation, braking,
Perform each control of OFF. (DPA) is the output of the microcomputer (COM)
Port (p_Two), (P_ThreeMovement of lens by signal from)
Table for displaying the direction, focus, and focus detection failure warning
It is an indicating part.   (ENL) is a lens driven by a lens drive motor (MOAF)
Pulse for monitoring the driving amount (motor rotation amount)
Output encoder, (ENAP) is the lens aperture
Encoder that outputs pulses to monitor the
It is. (SEC) is the output port (p_Four) Is “Low” level
When the pulse from the AF encoder (ENL) is
igh "level, the signal from the aperture encoder (ENAP)
To the input terminal (CNT
R). Microcomputer
(COM) has an event counter inside.
The event counter is preset with data,
The contents of the event counter for each pulse input to the child (CNTR)
Is counted down and the content of the event counter becomes 0
When this happens, an interrupt is triggered.   (S₁) Indicates that the shutter is closed at the first stage of pressing the release button.
This switch is an optical switch.₁) Closing signal
Is the microcomputer (COM) interrupt input terminal (INT₀) And input port
(P_Five). (S_Two) Is the release button pressed
This is a release switch that is closed at the second stage.
Leeds switch (S_Two) Is applied to the input port (p₆)
Is input to (S_Three) Is closed when the exposure control operation is completed.
Reset switch that is released upon completion of winding and charging
Switch, this reset switch (S_Three) Closing signal
Is the input port (p₇).   (GV) is the power supply circuit and the output port (p₈) To output
When the power control signal (PWC) is low.
Make. This power circuit (GV) is the output of the power battery (BA)
Output high voltage (HV) and low voltage (LV) based on
You. High voltage (HV) interfaces with the receiver (DT)
Power supply for circuit (IFC). Also, low voltage (LV)
Display (DPA), encoder (ENL), (ENAP),
Data selector (SEC) and film sensitivity reading described later
Circuit (ISD), lens circuit (LEC), photometry and A / D conversion
(MEC), power supply for decoder / driver (DDR)
Motor control circuit (MDA), (MDF), display (DS
P), microcomputer (COM) is power line from power battery (BA)
Receive power directly through (EV).   (ISD) is a film sensitivity reading circuit,
Reads and outputs ISO data indicating film sensitivity on the unit
Port (p₉) From the film sensitivity reading circuit selection signal (CS
IS) goes to the “Low” level, the microcomputer (COM)
The film speed data is synchronized with the serial clock (SCK).
Data to the serial input terminal (SIN)
You. (LEC) is a lens circuit provided in the interchangeable lens
is there. This lens circuit (LEC) is disclosed in, for example,
It has a circuit configuration disclosed in Japanese Patent No. 40408,
Output port (p_Ten) From the lens circuit selection signal (CSL)
When it goes to “Low” level, the serial clock (SCK)
Synchronously, the type stored in the ROM in the lens circuit (LEC)
Sends various data serially to the serial input terminal (SIN)
Put out. Here, fixed storage in ROM in lens circuit (LEC)
Data is stored in a fixed focus lens and zoom lens.
Will be described separately.   Table 5 is for fixed focus lenses and Table 6 is for zoom lenses.
3 shows the storage contents of the in-lens ROM in each case. A
Dress 01 has the same mounting data for all lenses.
(ICP) is fixedly stored. Open to address 02
Aperture value (Avo), maximum aperture value (Avmax) at address 03
Is fixedly stored. Changes in aperture value due to zooming
In the case of a zoom lens, the aperture at the shortest focal length
The value is fixedly stored. In the case of a reflective telephoto lens,
In this case, since the aperture is fixed, Avo = Avmax. Fixed
Address 04 for focus lens, zoom lens
Stores the focal length (f) data at addresses 10-1F
Have been. Note that more than 10 addresses for a zoom lens
The lower 4 bits 0 to F in the zoom
Addressed by the signal obtained from the
You. Defocus amount for address 05 or addresses 20-2F
To convert the driving amount of the lens drive motor (MOAF)
(K) is stored. Address 06 or address 30 to
On the 3rd floor, there is data on the amount of aperture change (ΔAv) due to zooming.
In the case of a fixed focus lens, ΔAv = 0
ing. Exit pupil at address 07 or addresses 40-4F
(Pz) data, address 08 or address 50 to 5F
Exit pupil diameter (P₀) Is stored. address
09 has an exit pupil inner diameter (P₀′) Is stored,
P for lenses other than reflective telephoto lenses₀'= 0
You. At address 0A or addresses 60 to 6F, the external image height correction data
Data ΔP₀Is stored at the address 0B.
ΔP₀′ Is stored, and for lenses other than the reflective telephoto lens,
Inner image height correction data ΔP₀'= 0.   (DSP) is a display circuit, sent from the microcomputer (COM)
Display based on incoming display data. (MEC) is measured
Light and A / D conversion circuit, low from power supply circuit (GV)
Photometric operation starts when voltage (LV) power supply is started
And the output port (p₁₂) From A / D conversion enable signal (ADEN)
A / D conversion is repeated at a fixed cycle when
Is done. And the output port (p₁₁Photometry from A) and A / D
When the conversion circuit selection signal (CSME) goes low, A /
The data converted and latched is serial clock
Clock (SCK) and sent to the microcomputer (COM)
You. (DDR) is a load drive circuit, which is a microcomputer (COM)
Data transmitted via the data bus (DBDR)
Code and drive the load according to the decoding result. load
For release magnet (RLM), for aperture control
Magnet (APM), front curtain control magnet (1CM), rear
Curtain control magnet (2CM), film feed and exposure control
Control mechanism charging motor (MOCH) and its driver
(MDF). X is an oscillator.   Hereinafter, based on the flowcharts of FIG. 10 to FIG.
Next, the operation of the camera system will be described. Explanation below
In the above, the symbol “#” indicates the program step number.
Shall taste. When the release button is operated,
Pressing the first step of the photometry switch (S₁) Is closed and interrupted
Input terminal (INT₀) Is input to the microcomputer (CO
M) is the interrupt routine INT in Fig. 10.₀Start operation from
You. First, the output port (p₈) Output power control signal
Signal (PWC) to “Low” level to activate the power supply circuit (GV).
(# 1). Next, the interface circuit (IF
C), display circuit (DSP), photometry and A / D conversion circuit (MEC)
Outputs reference clock (CKOUT) and is stored in CCD
Performs CCD initializing operation to sweep out charges (# 2, #
3). Next, the CCD charge storage operation is started, and the charge
At the end of the accumulation operation, the interrupt input terminal (INT₁) Interrupt signal
And the output port (p₁₂A / D conversion permission signal from
Signal (ADEN) is set to “Low” level and the photometric value is A / D converted.
(# 4, # 5, # 6).   Next, the routine proceeds to the photometry routine, where the lens is
From the film container to the film sensitivity data (IS
O data) (# 7, # 8). Next,
Rug IFF₁, IFF_TwoIs determined. IFF₁Is in focus
Then the flag is set to 1, IFF_TwoIs in focus
Is set when photometric data is imported after
It is. Therefore, when out of focus or out of focus
The metering data is not
When optical data is captured and data is captured after focusing
Flag IFF_TwoSet to 1 and move to the calculation routine
You. Also the flag IFF₁, IFF_TwoIf both are 1,
Calculation routine without inputting photometric data
(# 9- # 13).   In the calculation routine, first, in step # 14, the lens
Determines whether the mounting signal ICP is input, and
Step # 15 if entered, # 16 if not entered
Move to In step # 15, the maximum aperture value is Avo
Determines whether the large aperture value Avmax is equal (Avo = Avmax)
Do another, and if it is a reflective telephoto lens, Avo = Avmax, so # 1
6 、 If Avo ≠ Avmax is a normal interchangeable lens, # 19
Move to Tep. First, when the lens is not attached,
If a telephoto lens is attached,
However, aperture control is not possible and the aperture is considered fixed.
I have no choice. Therefore, in step # 16,
) = Bv-Av (Bv is the subject brightness, Av is the fixed aperture value)
During exposure by adding the ISO value Sv indicating film sensitivity
Calculate the interval Tv. Then, attach the lens in step # 17
To determine if a lens is not attached.
Displays the exposure time in step # 18, and the F value is a warning table
(For example, “−−”). Meanwhile, the lens is attached
If it is a reflective telephoto lens,
Tv and fixed aperture value (open aperture value Avo = maximum aperture value Avma
x) and are displayed in step # 21. In step # 15
If it is determined that the lens is not a reflective telephoto lens, the
In the step, (photometric data) = Bv-(Avo + ΔAv), Avo + Δ
Av + Sv is added to calculate the exposure value Ev, and based on this exposure value Ev
Aperture value (# 20)
The Av and the exposure time Tv are calculated and displayed (# 21).   When the above operation is completed, the flag AEF is set to 1.
You. This flag is set to 1 when the exposure calculation ends.
Flag. Next, the state of the flag CF is determined, and CF is determined.
If = 1, the process proceeds to the AF routine. This flag CF
The CCD charge accumulation operation during the operation of the light routine or arithmetic routine
When the work is completed, the exposure calculation must be completed once.
For example, after capturing data from the CCD,
Exposure calculation, and then from this step the AF
Provided to transfer to the chin.   In step # 24, release switch (S_Two) Is closed
In step # 25, the photometric data after focusing is
Data to determine whether the exposure control value has been calculated,
If both conditions are satisfied, the routine proceeds to the exposure routine,
The output control operation is performed. On the other hand, if the conditions are not satisfied, #
Photometric switch (S₁) Is closed
And if it is closed, it goes to the metering routine.
Return, if not closed, execute the stop routine
Do.   In the stop routine, first reset all flags.
Output port (p_Four) To “Low” level and display
The data to be turned OFF (state in which nothing is displayed) is displayed on the display circuit (D
SP), stop the motor (MOAF), and
(CKOUT) output is stopped and the power supply circuit (GV) is disabled.
A / D conversion is disabled when the signal (ADEN) is set to “High” level.
And the microcomputer (COM) stops operating (# 26 to # 3
2).   Next, the operation of the AF routine will be described with reference to FIG.
When the CCD accumulation operation is completed, the interface circuit (I
FC) to the interrupt input terminal (INT₁) Receives an interrupt input signal.
And perform the operation from # 39. First, in step # 39
Determines whether an interchangeable lens is attached, and
If not, go to step # 40.
Move to operation from # 51 and fetch data from CCD
No focus, focus detection, lens driving operation, etc. are performed. # 40
In the step, three rows of CCD output from the light receiving unit (DT)
Corresponding analog signal to interface circuit (IFC)
A / D conversion sequentially and import to microcomputer (COM)
No. Then, the flag CF is set to 1 and the flag AEF is set to 1
To determine if the flag AEF is set to
If it is set to 0, the first photometry routine and calculation
The return address (INT₁Is the interrupt
Return to step (execution step). And the photometer
When the routine and the calculation routine are completed,
Then, CF = 1 is determined in the step and the process returns to the AF routine. # 42 Station
If AEF = 1 in the step, the capture of CCD data ends
And immediately shifts to the AF routine.   In the AF routine, first, the flag CF is set to 0,
The process proceeds to subroutine SUB1 shown in FIG. This subroutine
In the chin SUB1, the exit pupil position Pz and the exit pupil outer diameter P₀And based on
The focus detection area within the on-axis ranging frame A
A. Next, in step # 44, shoot from the lens
Exit pupil diameter P₀And external image height correction data ΔP₀And camera body
Deformation exit pupil for off-axis ranging frames B and C from constant k
Diameter₀Is calculated. Next, the subroutine SU shown in FIG.
Move to B2, exit pupil position Pz and deformed exit pupil outer diameter₀And base
Focus detection is possible among the off-axis ranging frames B and C
Select the ranging area. Next, exit pupil in step # 45
Inner diameter P₀′ = 0, P₀If '= 0
Lens, and the process immediately proceeds to step # 47. one
One, P₀If '≠ 0, it is a reflective telephoto lens, as shown in FIG.
Move to subroutine SUB3. In subroutine SUB3
Exit pupil position Pz data and exit pupil inner diameter P₀′ Data
In the on-axis ranging frame A, the focus can be detected.
Select the distance measurement area, and
And the distance measurement selected in this subroutine SUB3
Finalize the area. Next, in step # 46
Exit pupil inner diameter P₀'And internal image height correction data ΔP₀及
And the modified exit pupil diameter from the constant k 'of the camera body₀′
calculate. Next, proceed to the subroutine SUB4 shown in FIG.
Exit pupil position Pz and deformed exit pupil inner diameter₀′ And off-axis measurement
Select detectable ranging area from distance frames B and C
And selected in subroutine SUB2, and
Finally, the ranging area selected in subroutine SUB4
decide.   In the step # 47, the data Pz, P regarding the exit pupil₀,
P₀′,₀,₀′ Is selected.
If not, focus detection is performed
Without moving to step # 51. On the other hand, even if one is selected
If there is a selected ranging area, for each selected ranging area
(The defocus amount is detected) (# 48).
And reliable data can be obtained for each ranging area.
All data with unreliable data
If there is, the process proceeds to step # 51 (# 49, # 50). #Five
In the first step, the flag IFF_TwoIs set to 1. this
Indicates exposure when focus detection is not possible
This is because the control operation can be performed. And detection
Warning that the operation is not possible, and the CCD accumulation operation
Start and INT₁Of the photometry routine and
And return to the return address in the calculation routine.   Get at least one reliable data in step # 50
If it is determined that the
To perform statistical processing. This statistical processing includes, for example,
Also use the signal of the rear pin, or if multiple data
When the defocus amount is within the range, the multiple subjects
Processing such as adopting a defocus amount that falls within the point depth
There is reason. And the defaults found by statistical processing
It is determined whether or not the scum amount is within the focus area, and if it is outside the focus area,
In step # 62, if it is within the focus area, the process proceeds to step # 70. #
In step 62, the defocus direction is displayed and the default
Multiply the scum amount by the conversion coefficient (K) to obtain a lens drive motor
(MOAF) drive amount is calculated (# 63), and this drive amount
Preset to the event counter (EVC) (# 64). Soshi
To enable the event counter interrupt (# 65)
Operate the drive motor (MOAF) (# 66). And
Return to the return address of the photometry routine and the calculation routine. Less than
Then, while driving the lens, the photometry routine and calculation routine
Repeat. Also, an engine that monitors the lens drive amount
The pulse from the coder (ENL) passes through the selector (SEC)
Input from the terminal (CNTR) to the event counter,
The contents of the event counter are decremented.   When the content of the event counter reaches 0, the event
Interrupt (EVC interrupt), and
Perform the operation from the step. # 100 steps, AF
Determine whether the camera is operating or not.
Then go to step # 101 and stop the motor (MOAF)
CCD accumulation to perform focus detection for confirmation
Start the operation (# 102) and enter the interrupt input terminal INT₁From
From the step # 7 after enabling the interrupt (# 103)
To the photometry routine of. Note that in step # 104
This will be described later.   In the flow of FIG. 11, focusing is performed in step # 61.
If it is determined that the
Display. And the flag IFF in the step # 71₁1 in
To go to the photometry routine from step # 7.
Run. Therefore, once the in-focus state can be confirmed,
Photometric switch (S₁) As long as focus detection and
No lens drive is performed.   In step # 24 of FIG. 10, the release switch (S_Two)
Is closed, flag IFF in step # 25_TwoSet to 1
If it is, the process proceeds to the exposure control routine of FIG.
First, the AF display is turned off in step # 75, and the
Operate the release magnet (RLM) with the
Start the operation of the control mechanism. And of the interchangeable lens
Whether the camera is mounted and whether a reflective telephoto lens is mounted
Is determined (# 77, # 78), and the lens is not
Moves to step # 83 when the lens is attached
However, the narrowing-down control operation is not performed. On the other hand, a normal lens
If is installed, first, control the throttle in step # 79.
Determines whether the value (Av) is equal to the open aperture value (Avo)
Then, if Av = Avo, similarly, proceed to step # 83.
You. On the other hand, if Av ≠ Avo, the number of steps to be narrowed down (Av−Avo)
Set the event counter (EVC) and the port (p_Four)
Set the level to “High” to monitor the amount of narrowing down.
Pulse from coder (ENAP) goes out of selector (SEC)
Force (# 80, # 81, # 82). And # 8
3, Wait a certain time in step # 84. Narrow down during this time
When the operation is performed and the event counter is interrupted,
Operate the aperture magnet (APM) in 104 steps to squeeze
Stop loading. And after a certain time,
The raising of the reflection mirror has been completed, and the front curtain magnet (1C
M) to start running the front curtain and
The counting is performed (# 85, # 86). The count ends
And operate the rear curtain magnet (2CM) to drive the rear curtain
Start (# 87). Then, when the trailing curtain is completed,
Set switch (S_Three) Is turned ON (# 88). Re
Set switch (S_Three) Is ON, the charge mode
(MOCH) to control film winding and exposure control
Allow the mechanism to charge and complete this operation and reset
Switch (S_Three) Is turned off (# 89, # 90). So
And reset switch (S_Three) Is turned off, Lerry
Release your finger from the button, and press the metering switch (S₁) Is off
Wait for it to become (# 91). Photometric switch (S₁) Is off
Then, the stop routine operates and then the photometry switch
Switch (S₁) Is turned ON and the microcomputer (COM) is started.
Stop operation until it stops.   Subroutines SUB1, SUB2, SUB3, SUB4 shown in FIG.
Specific contents are shown in Fig. 13, Fig. 14, Fig. 15, and Fig. 16.
Shown respectively. In subroutine SUB1 of FIG.
Exit pupil position Pz and exit pupil outer diameter P₀On-axis distance measurement frame
Select a distance measurement area from the program A. First of all,
P in Tep₀<P₀₁And determine P₀<P₀₁If, detectable
There is no effective distance measurement frame, and proceed to step # 128
You. Meanwhile, P₀≧ P₀₁Then, in step # 111, P₀<
P₀₂And determine P₀₂> P₀≧ P₀₁Then, in step # 112
Y₁₁Is set to the address. Hereinafter, similarly, in the step # 113,
Up in P₀₃> P₀≧ P₀₂Then, in step # 114, Y₁₂A
Set to dress, # 115 step P₀₄> P₀≧ P₀₃If
If Y in step # 116₁₃To the address, # 115
In the step of P₀≧ P₀₄Then, in step # 117, Y₁₄To
Set to address.   Next, the same applies to the exit pupil position Pz according to Table 1.
Is determined, and in step # 118, Pz ≧ Pz_FourThen # 12
Move to step 8 and Pz in step # 118_Four> Pz ≧ Pz_Three
Then X in step # 120₁₄To the address, and #
Pz in 121 steps_Three> Pz ≧ Pz_TwoThen step # 122
And X₁₃To the address, and step # 123 of Pz_Two> Pz
≧ Pz₁Then X in step # 124₁₂Set to address
Pz in step # 123₁> If Pz, step # 125
X₁₁Is set to the address. As a result, Table 1
Is the address data (X_1i, Y_1i) To set
The address data (X_1i, Y_1i)so
Specify the ROM table where Table 1 is stored, and
The stored data of the focus area where focus can be detected is recorded.
Set in the ERAR This data is used for ranging areas I to IV.
4 bits data corresponding to
The bit corresponding to the effective ranging area is 1, and the focus cannot be detected.
The bit corresponding to the appropriate distance measurement area is 0. did
Thus, for example, address data (X₁₁, Y₁₁) Is specified
Then, "0001" or "0011" data, address data
(X₁₄, Y₁₃) Is specified, the data of “0001” or “1001”
Data, address data (X₁₁, Y₁₄) Is specified, "1
111 "is set in the register ERAL.
In step # 128, the focus detection area
Therefore, “0000” is set in the register ERAL.   In subroutine SUB2 in FIG.
Exit pupil position Pz and deformed exit pupil outer diameter₀Off-axis distance measurement frame
Select the focus detection area from among the programs B and C
Low. As in subroutine SUB1 in FIG. 13, # 13
In 0 steps₀<₀₁Or the step # 138
Pz ≧ Pz_FourThere is no focus detection area when
Therefore, “0000” is set in the register ERBCR. further,#
In 131 steps₀₁≤₀<₀₂Then # 132
Y_{twenty one}To the address, and in step # 133₀₂
≤₀<₀₃Then, in step # 134, Y_{twenty two}The address
And in step # 135₀₃≤₀<₀₄If
If Y in step # 136_{twenty three}Set to address, # 135
In the steps₀₄≤₀Then, in step # 137, Y_{twenty four}
Is set to the address. In addition, Pz in step # 139_Three
≤Pz <Pz_FourThen X in step # 140_{twenty four}To address
Set and Pz in step # 141_Two≤Pz <Pz_ThreeThen # 142
X in steps_{twenty three}To the address, and step # 143
With Pz₁≤Pz <Pz_TwoThen X in step # 144_{twenty two}Address
And set Pz in step # 143₁If it is> Pz, # 145
X in steps_{twenty one}Is set to the address. And settings
Address (X_2i, Y_2i) To specify the ROM table and
The data stored at the address of
Set.   In subroutine SUB3 shown in FIG.
The exit pupil position Pz and the exit pupil inner diameter P₀′ And the on-axis distance measurement frame
Select the focus detection area in
Eventually, the exit pupil outer diameter P₀And exit pupil inner diameter P₀′
A focus detection area that can detect focus with the on-axis distance measurement frame A
select. First, according to Table 2, the components shown in Figs.
Address data (X_3i, Y
_3i) Are set (# 151 to # 166). And this address
Data (X_3i, Y_3i) To specify the ROM table and
Read the data stored in the address. And this
Data and already set in register EAR by subroutine SUB1
The logical product of the data and
The result is set in the register ERAR. This allows the selection on the one hand
And the bit corresponding to the ranging area is 1
If the other is also 0, the bit becomes 0 and the exit pupil outer diameter
P₀, Exit pupil inner diameter P₀The distance measurement area determined by both
It will be set to the star EAR, P₀'≧ P₀₄′
Or Pz <Pz₁When, the focus detection area is
Since there is no register, "0000" is set in the register EAR.   In subroutine SUB4 of FIG.
Exit pupil position Pz and deformed exit pupil inner diameter₀′ And off-axis distance measurement
Select a focus detection area that can detect focus from among
And finally the deformed exit pupil outer diameter₀And deformed exit pupil inner diameter
₀′, Focus detection with off-axis ranging frames B and C
Select a suitable ranging area. First, FIG. 13 to FIG.
Address data (X_4i,
Y_4i)₀′, Pz
Data (X_4i, Y_4i) To specify the ROM table
Read the data stored in the address. And this
Data and already set in register ERBCR in subroutine SUB2
The logical product of the data and
By setting the result in the register ERBCR, the final focus
Set detectable ranging area. In addition,₀'≧
₀₃′, There is no focus detection area
Then, "0000" is set in the register ERBCR.   In the above embodiment, the on-axis measurement
Equipped with a distance frame A and off-axis distance measurement frames B and C.
Frames A, B and C are divided into ranging areas I to IV
However, the ranging frames are, for example, ranging frames A,
Only B and ranging frames A and C may be used. Also, distance measurement
As the frame A alone, the inside of the distance measurement frame A
The regions may be divided as follows. Or three ranging frames
By setting areas A, B, and C
And do not divide the area inside the distance measurement frames B and C
You may.   As the exposure control mode, P mode (program exposure)
Mode), but A mode (aperture priority AE mode)
Mode), S mode (shutter speed priority AE mode), M
Mode (manual mode).
When the lens is attached, it is different from a normal lens
is required. That is, in the A mode, the P mode
Exposure automatically set for a fixed aperture as in
It is time, and in S mode and M mode, fixed aperture
The set exposure time is reached.   The focal point for the reflective telephoto lens in the present embodiment
In the detection system, the exit pupil outer diameter, exit pupil inner diameter, exit pupil position
Multiple focus detection areas based on the
To determine whether focus detection is possible
However, only one focus detection area may be used.
Determines whether focus detection is possible for the detection area
You may comprise so that it may be.   Further, the reflective telephoto lens in this embodiment has a focal point.
In order to determine whether or not detection is possible,
Data on the inner diameter of the exit pupil and the position of the exit pupil are stored.
However, data indicating whether the lens can detect focus is also available.
You may comprise so that it may output. In this way,
With the conventional focus detection function, the outer diameter of the exit pupil
Focus based on inner diameter of exit pupil and data on exit pupil position
Also supports those that do not have a function to determine whether detection is possible
be able to. (The invention's effect)   Focus detection system for reflective telephoto lens according to the present invention
The outer diameter of the exit pupil from the reflective telephoto lens,
Based on the inner diameter of the exit pupil and the data on the exit pupil position,
Whether the point detection means can detect optically accurate focus
Performs discrimination and activates focus detection means if focus detection is possible
When using a reflective telephoto lens.
Can correctly determine whether focus detection is possible.
Yes, and therefore cheap and compact reflective telephoto lens
Can realize a focus detection system using
Has the effect.   In the reflective telephoto lens according to the merged invention,
Lens specific exit pupil outer diameter, exit pupil inner diameter, and exit pupil position.
Data to be read is fixedly stored, and read signals from the body
Send these data to the body based on
The body with the reflective telephoto lens
The vignetting of the luminous flux due to the exit pupil of the reflective telephoto lens
Can be correctly determined, and as a result,
Can be used to determine whether focus detection using
There is an effect that can be cut.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of the present invention, FIG. 2 is a perspective view of a focus detection system according to an embodiment of the present invention, and FIG. FIG. 4 is an explanatory view of the exit pupil plane of the reflective telephoto lens used in the above-mentioned embodiment, FIG. 5 is an explanatory view of a pupil-related constant of the focus detecting optical system used in the above-described embodiment, and FIG. FIG. 7 is an explanatory view of an on-axis focus detection optical system used in the above-described embodiment, and FIG. 8 is a CCD used in the above-described embodiment.
FIG. 9 is a diagram showing an illuminance distribution on an image sensor array, FIG. 9 is a circuit diagram of a camera system using the focus detection system of the above, and FIGS. 10 to 16 are flowcharts for explaining the operation of the same. 1 is optical means, 2 ₁ and 2 ₂ are light receiving means, 3 is focus detecting means,
4 is a discriminating unit, 5 is an operation permitting unit, 6 is a storage unit, 7 is a read signal input unit, 8 is a data sending unit, and ML is a reflective telephoto lens.

Continuing on the front page (72) Inventor Sho Sakumaru 2-30 Azuchicho, Higashi-ku, Osaka Osaka International Building Minorta Camera Co., Ltd. (72) Inventor Tokuharu Ishida 2-30 Azuchicho, Higashi-ku, Osaka Osaka International Building (56) References JP-A-62-75410 (JP, A) JP-A-61-159611 (JP, A) JP-A-59-65814 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) G02B 7/11 G03B 3/00

Claims (1)

(57) [Claims] Optical means for forming at least one pair of light images from light beams from at least one pair of different areas on the exit pupil surface of the reflective telephoto lens; at least one pair of light receiving means for receiving the light images; and at least one pair of light receiving means At least one focus detection means for performing focus detection by detecting a relative displacement of an optical image based on an output of the means, an exit pupil outer diameter read from a reflective telephoto lens, an exit pupil inner diameter, and an exit pupil position Determining means for determining whether the focus detection means can perform optically accurate focus detection based on a combination of the optical means and the optical system of the reflective telephoto lens based on the data on Means for operating the detecting means, the focus detecting system for the reflective telephoto lens. 2. A reflection telephoto lens attached to a camera body having a focus detection means, wherein the storage means permanently stores data unique to the lens, a means for inputting a read signal from the camera body, and Means for sequentially transmitting data stored in the storage means to the camera body,
A reflective telephoto lens, wherein data stored in the storage means includes data relating to the outer diameter of the exit pupil, the inner diameter of the exit pupil, and the position of the exit pupil of the lens.