JPH01287613A - Reflecting telephoto lens capable of outputting lens information - Google Patents

Abstract

PURPOSE:To easily but accurately discriminate the correctness of focus detection by storing the open aperture value decided by the light beams outside a mirror lens in a ROM as aperture value signals for determinating the correctness of the focus detection of the reflecting telephoto lens. CONSTITUTION:The outside open aperture value which is decided by the light beams II on the outside when no vignetting of the inside light beams is produced by an auxiliary mirror is used as the aperture value for discriminating the correctness of the focus detection to be stored in the ROM of the mirror lens. The aperture value is different from ordinary aperture value decided by the luminous flux between the outside light beams I and inside light beams III, but the open aperture value decided by the outside light beams I which becomes a primary factor for the correctness of focus detection. Therefore, correctness of focus detection can be performed simply but accurately.

Description

[Detailed Description of the Invention] Foresight! ΔWeigher History 91 The present invention is capable of being detachably attached to a camera body having a built-in phase difference detection type focus detection device, and the focus detection lens information is stored in a ROM.
The present invention relates to an interchangeable lens that can store information on a camera body and output this information to a camera body, and particularly relates to a reflective telephoto lens.

The ability to detect focus in the combination of the focus detection element (for example, CCD line sensor) on the camera body side and the optical system of the interchangeable lens is determined by whether the projected image above the exit pupil of the CCD line sensor is Determined by whether or not it is eclipsed by the exit pupil. Therefore, in the case of general refractive lenses, it is possible to determine whether vignetting occurs when the maximum aperture is at its smallest due to zooming or focusing, so the aperture value of the smallest maximum aperture is used as the aperture for determining focus detection. For example, Japanese Patent Laid-Open No. 60-4915 proposes storing the value AFAvo in the ROM of the lens.

However, since the maximum aperture value of a reflective telephoto lens is determined by the area of the light beam sandwiched between the outer ray and the inner ray (which is eclipsed by the secondary mirror), the aperture value for determining focus detection is If this normal aperture value is used, the aperture value will be darker than the aperture value corresponding to the outer rays when there is no clarification of the inner rays due to the secondary mirror.In other words, even though focus detection is possible with the outer rays. However, there was a possibility that it would be determined that focus detection was impossible. It is conceivable to determine whether focus detection is possible based on the position and diameter of the exit pupil, but this determination is complicated and cannot be said to be practical.

An object of the present invention is to allow focus detection to be performed easily and accurately when performing focus detection using such a reflective telephoto lens.

2) The present invention uses, as the aperture value for determining whether focus detection is possible or not stored in the ROM of the reflective telephoto lens, the outer open aperture value determined by the outer light ray when there is no clarification of the inner light ray by the secondary mirror. It is characterized by the fact that it was used.

Raw-1 The aperture value used to determine whether or not focus can be detected with a reflective telephoto lens is different from the normal open aperture value, which is determined by the light flux sandwiched between the outer ray and the inner ray, but the aperture value used for determining whether or not focus can be detected is different from the normal aperture value, which is determined by the light flux sandwiched between the outer ray and the inner ray. Since the open aperture value is determined by , it is possible to easily and accurately determine whether or not focus detection is possible.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the -eye reflex camera is provided with a photographing lens 11 on the optical axis 10, a main mirror 12 is provided behind the photographic lens 11, and a film exposure lens is provided behind the main mirror 12. A surface 13 is provided so that the photographing light beam that has passed through the photographic lens 11 is reflected upward by the main mirror 12 and guided to a finder optical system (not shown).

At least a part of the main mirror 12 is formed into a half mirror, and a sub mirror 14 is provided between a part of the half mirror of the main mirror 12 and the film exposure surface 13. The focus detection device 1 reflects the focus detection light beam that has partially passed through the sub mirror 14 downward.
It will lead to 5.

During photographing, the main mirror 12 and the sub mirror 14 are rotated upward and retracted from above the optical axis 10, and the photographing light flux that has passed through the photographic lens 11 forms an image on the film exposure surface 13. It comes to give an imagewise exposure.

The focus detection device 15 is provided with a sensor substrate 17 to which a line sensor such as a CCD (photoelectric conversion element rows H6a, 16b, and 16c) is attached.

Among the line sensors 16a to 16c, one line sensor 16a is arranged at a horizontal position including the optical axis 1o, and 2
The line sensors 16b and 16c are
They are arranged at vertical positions not including the optical axis 1o on both sides of a. Line sensor 16b.

16c is set at approximately 90 degrees with respect to the line sensor 16a.

A separator lens plate 18 is provided in front of the sensor substrate 17, and the separator lens plate 18 has separator lenses 1 corresponding to each of the line sensors 16a to 16c.
8a to 18c are integrally formed.

One aperture mask is provided immediately in front of the separator lens plate 18, and the aperture mask 19 has openings 19a to 19c corresponding to the separator lens plates 18a to 18c.

A reflecting mirror 20 is provided that faces the aperture mask 19 and the sub-mirror 14, and the reflecting mirror 20 directs the focus detection light beam reflected downward by the sub-mirror 14 to the aperture mask apertures 19a to 19c and the separator lens. 18a-18c
The line sensors 16a to 16c are guided through the line sensors 16a to 16c.

Condenser lenses 21a to 21e facing the aperture mask openings 19a to 19c are provided between the reflection mirror 20 and the submirror 14, and the condenser lenses 2
A field mask 22 having openings 22a to 22c for separating the focus detection light beam so as to correspond to the line sensors 16a to 16c having different positions and directions is provided on the upper surface of the lenses 1a to 21c.

The reference part light flux a and the reference part light flux A passing through mutually different regions 11a and llb and lie and 11d on the exit pupil plane of the photographing lens 11 are received by each line sensor 16a to 16c, and the light distribution pattern of the image is obtained. into an electrical signal,
Automatic focus detection is performed by determining the correlation between them using a correlator (not shown), and automatic focus adjustment is performed by moving the photographing lens 11 back and forth using a drive mechanism based on a shift signal from the correlator.

In this case, in addition to the line sensor 16a at the horizontal position, line sensors 16b and 16c are also provided at the vertical position, so focus detection in the horizontal and vertical directions can be performed simultaneously, and focus detection on horizontal lines, etc. It became possible.

On the other hand, the line sensor 16m is arranged with a predetermined length including the optical axis 10, so there is no pressure between them, but the line sensors 16b and 16c are arranged at vertical positions that do not include the optical axis 1o. When considering various types of interchangeable lenses, it is important to arrange the focus detection light beam so that it is difficult to blur, that is, to maximize the pupil margin.

Now, as shown in Fig. 2, the projected image of the element on the axis falls between the outer ray and the inner ray without any sharpness, and the AF
(distance measurement) is possible. However, if we replace it with the equivalent aperture (that is, the normal maximum aperture value) assuming that there is no clarification of the inner ray due to the secondary mirror, clarification occurs in the projected image of the element (as shown by the broken line), and this If the value is output as a ROM value to the camera body, it will be compared with the distance measurement limit aperture value of the camera body itself, and it will be determined that measurement is not possible.

Therefore, in the present application, the maximum aperture value determined only by the outer rays is stored in the ROM and output as the AP maximum aperture value (AFAVo). Note that when the outer rays decrease (darken) due to lens movement such as focusing, the value at that time is used.

Also, since the normal aperture value is used as the ROM value for the maximum aperture value used for exposure control, it is not possible to use a normal lens (A V O ≦
Unlike AFAV, ), the relationship is AV, > AFAV, ), so it can be determined that it is a reflective telephoto lens.

For example, in the case of a refractive lens whose distance measurement limit aperture value AFAVI is F6.7, the maximum aperture value (D = (X)) The maximum aperture value after F5.6 (CD = 1s) is F6.3. A
V, -5,6,AFAVo=6.3AFAV! (6,
7)>AFAV. (6, 3), and it is determined that distance measurement is possible.

In the case of a reflective lens, the maximum aperture value (D = ω) The maximum aperture value after F8 is extended (D = 1 m) The maximum aperture value of F8.5 outer rays (
D = (X)) F6.3 If the open aperture value after the outer ray is delivered (D = 1 m) F6.69, then AVO = 8. AFAV, = 6.69AFAV
I<6.7n> AFAVO (6.69n, and it is determined that distance measurement is possible.

AFAV this like a normal lens. = 8.5, then AFAVI(6,7) < AFAV. (8, 5), and it is determined that distance measurement is not possible.

Next, how to determine whether it is a reflective telephoto lens will be explained.

Reflective telephoto lenses generally do not have an aperture adjustment mechanism, so the maximum aperture value (AVO) and maximum aperture value (AVmax)
are equal.

ex AVo=F8. Since AVmax=F8, A
A possible method is to determine that it is a reflective telephoto lens from the relationship V 6 = A V n + ax.

However, the ROM signal is also AV.

= A V @ax In addition to the reflective telephoto lens, there are other lenses as shown below, so it is dangerous to make a determination based only on this relationship.

For example, in the case of a bellows macro lens, this lens has an aperture adjustment mechanism and a manual aperture setting member on the lens itself, but it does not have an automatic aperture presetting mechanism, so the aperture cannot be controlled from the camera body side. When set to a certain aperture value, it is treated the same as a lens that has that aperture value as its maximum aperture value and does not have an 8N side aperture. Therefore, the same value should be stored in A V o and A V max of this lens. The same applies to tilt lenses and soft lenses.

FIG. 3 is a circuit diagram of a camera system to which the present invention is applied. (DT) is a light receiving part for focus detection, and is 1 in Fig. 1.
It has CCD image sensor arrays indicated by 6a, 16b, and 16c. (I FC) is an interface circuit that controls the operation of the CCD image sensor array, A/D converts the signal read from the CCD image sensor array, and sends it to the microcontroller (COM) via the data bus (DBAF). It has a function of transmitting information, and a function of transmitting the completion of the charge accumulation operation of the CCD image sensor array to the interrupt input terminal (INT, ) of the microcomputer (00M). Note that the charge accumulation time in the CCD image sensor array is controlled by the output of a light receiving section (not shown) that monitors the brightness of the subject.

(MOAF> is the lens drive motor for AP, (M
OA) is the motor control circuit, which controls forward rotation, reverse rotation, brake, and FF using signals from the output ports (po) and (p+) of the microcomputer (COM). (DPA) is the microcomputer (COM). This is a display section for displaying the direction of movement of the lens, focusing, and a warning that focus cannot be detected based on signals from the output ports (p2) and (p-).

(ENL) is an encoder that outputs a pulse to monitor the lens drive (motor rotation amount) by the lens drive motor (MOA F >), and (ENAP) is an encoder that outputs a pulse to monitor the amount of aperture of the lens. It is an encoder that outputs. (SEC> is the output port (ρ,
) is at “Low” level, the AP encoder (
This is a data selector that sends pulses from the aperture encoder (ENAP) to the event counter input terminal (CNTR) when the level is "High". An event counter is provided inside the microcomputer (COM), and data is preset in the event counter.
) The contents of the event counter are counted down every time a pulse is input to ), and when the contents of the event counter reach 0,
An interrupt occurs.

(Sl) is a photometry switch that is closed at the first step of pressing the release button, and the closing signal of this photometry switch (S+) is sent to the interrupt input terminal (INT,) of the microcomputer (COM).
is input to the input port (p,). (S2) is a release switch that is closed at the second step of pressing the release button, and a closing signal of this release switch (S2) is input to the input port (p6).

(S,) is closed when the exposure control operation is completed, and the winding
It is a reset switch that opens when charging is complete.
The closing signal of this reset switch (S,) is input to the input port (p7).

(GV) is a power supply circuit, which operates when the power supply control signal (PWC) output from the output port (p, ) is at the "LO-" level. This power supply circuit (GV) is a power supply battery (
High voltage (HV) and low voltage (BA) based on the output of
LV). High voltage (HV)
) and interface circuit (IFC). Also, low voltage (LV) is applied to the display section (DPA), encoder (ENL), (ENAP), data selector (S
EC), and the film sensitivity reading circuit (ISD) described below.
, lens circuit (LEC), photometry and A/D conversion circuit (M
EC), decoder dry t<-(DDR) (7)
tfi tonari, motor controlled WO road (MDA), (MDF)
, display unit (DSP), and microcontroller (00M) are powered by batteries (
Receives power directly from BA) via the power line (EV).

(ISD) is a film sensitivity reading circuit which reads the ISO data indicating the film sensitivity on the film container, and when the film sensitivity reading circuit selection signal (C3IS) from the output capo (p=) becomes "Low" level. , film sensitivity data is input to the serial input terminal (SIN) in synchronization with the serial clock (SCK) from the microcontroller (COM).
Send serially to (LEC) is a lens circuit provided within the interchangeable lens. This lens circuit (LEC)
has a circuit configuration disclosed in, for example, Japanese Unexamined Patent Publication No. 59-140408, and the output port (p+.)
When the lens circuit selection signal (C3L) from the input terminal becomes 'Low' level, various data stored in the ROM in the lens circuit (LEC) are input to the serial input terminal (SIN) in synchronization with the serial clock (SCK). Here, the data fixedly stored in the ROM in the lens circuit (LEC) will be explained.

(The following is a margin) Table 1 shows the memory contents of the ROM in the lens in the case of a reflective telephoto lens. At address 011, data common to all lenses is fixedly stored as an attachment signal (ICP). Address 021 contains the open aperture value (A vo)
, the maximum aperture value (A vmax) is fixedly stored at address 031, and in the case of a reflective telephoto lens, the aperture is fixed, so A vo == A v+*ax. At address 041, point distance (f) data is stored. At address 051, a conversion coefficient (K) for converting the defocus amount into the drive amount of the lens drive motor (M OA F ) is stored.

Address 061 contains the amount of aperture change (△A) associated with zooming.
v) is stored, and in the case of a reflective telephoto lens, ΔAv=O. Address 071 contains data on the open aperture value (A F A vo) for focus detection, and address 081 contains data on the area off the optical axis (PO+), (PO
In the case of a 0-reflection telephoto lens in which data indicating whether focus detection in 2) is possible is stored, the open aperture value determined from the exit pupil outer diameter is stored as AFAvo. Furthermore, data indicating that off-axis distance measurement is not possible is stored as off-axis distance measurement possible/impossible data.

(DSP) is a display circuit, which performs display based on display data sent from a microcomputer (COM).

(M B C) is a photometry and A/D conversion circuit, and when the power supply of low voltage (LV) from the power supply circuit (GV) is started, photometry operation is started, and the output port (p, 2) When the A/D conversion enable signal (ADEN) from the controller becomes "Low" level, A/D conversion is repeated at a constant cycle. Then, when the photometry and A/D conversion circuit selection signal (C8ME) from the output boat (pz) becomes “Low” level,
The A/D converted and latched data is serially
The data is sent to the microcontroller (COM>) in synchronization with the clock (SCK). (DDR) is a load driving circuit that decodes the data sent from the microcontroller (COM) through the data bus (DBDR) and outputs data according to the decoding result. drive a load.

The loads include a release magnet (RLM), an aperture control magnet (APM), and a leading curtain control magnet (
ICM), rear curtain control magnet (2CM), film advance and exposure control mechanism charge motor (MOCH)
and its driver (MDF).

X is an oscillator.

Below, based on the flowcharts of FIGS. 4 to 6,
The operation of this camera system will be explained.

In the following description, the symbol "#" means a step number of the program. When the release button is operated, the photometry switch (S+) is closed by pressing the first step, an interrupt signal is input to the interrupt input terminal (INT, ), and the microcomputer (COM> Interrupt routine INT
, start the operation from.

First, the power supply control signal (pwc) output from the output port (p,) is set to "Low" level, and the power supply circuit (GV
) (#1), then interface circuit (IFC), display circuit (DSP), photometry and A/D
Reference clock (CK OUT) to conversion circuit (MEC)
) and sweeps out the charge accumulated in the CCD.
Perform OD initialization operation (#2゜#3) 0th order,
Start the charge accumulation operation of the CCD, enable the reception of an interrupt signal to the interrupt input terminal (NT,) at the end of the charge accumulation operation, and send the A/D conversion enable signal (ADEN) from the output port (p12). “L.

level, and convert the photometric value to A/D (#4゜#
5. #6).

Next, the process moves to the photometry routine, and lens data is acquired from the interchangeable lens, and film sensitivity data (IS) is acquired from the film container.
0 data) respectively (#7, #8), then,
Determine the status of flags IFF+ and IFF2. IFF
, is a flag that is set to 1 when the in-focus state is reached, and IFF is a flag that is set when photometric data is taken in after the in-focus state is reached. Therefore, when the camera is not in focus or when the photometric data is not captured even though it is in focus, the photometric data is captured, and when the data is captured after the focus is focused, the flag lFF2 is set to 1 and the process moves to the calculation routine. . Also, flag IFF,
If both IFF and IFF are 1, the process directly proceeds to the calculation routine without inputting photometric data (#9~
#13).

In the calculation routine, first, in step #14, it is determined whether or not the lens mounting signal CP is input. If so, the process moves to step #15, and if not, the process moves to step #16. In step #15, it is determined whether the open aperture value Avo is larger than the focus detection open aperture value AFAvo (Avo>AFAvo), and if it is a reflective telephoto lens, Av is determined.

>AFAvo, so go to step #16; if Avo<AFAvo, it's a normal interchangeable lens, so go to step #19.

First of all, if no lens is attached or if a reflective telephoto lens is attached, aperture control is of course impossible and the aperture must be considered fixed. Therefore, #16 In the step, (photometric data) = Bv - Av
(Bν is the subject brightness, Av is the fixed aperture value) and the ISO value Sv indicating the film sensitivity is added to the exposure time T.
Calculate v. Then, in step #17, it is determined whether or not a lens is attached. If a lens is not attached, the exposure time is displayed in step #18, and the F value is displayed as a warning (for example, "-1"). , On the other hand, if the lens is attached, it is a reflective telephoto lens, and the calculated exposure time Tv and fixed aperture value (rM maximum aperture value Avo+=maximum aperture value A v@ax) are calculated in step #21. indicate.

If it is determined in step #15 that it is not a reflective telephoto lens, then in step #19 (photometry data) = Bv - (
Avo+ΔAv) is added to Avo+ΔAv+SV to calculate the exposure value Ev, and based on this exposure value Ev, program exposure calculation (#20> is performed to calculate the aperture value Av and exposure time Tv, and this is displayed. (#21>.

When the above operations are completed, flag AFF is set to 1. This flag is a flag that is set to 1 when the exposure calculation is completed. Next, determine the state of the flag CF,
If CF=1, the process moves to the AP routine. This flag C
When the charge accumulation operation of the CCD is completed during the operation of the photometry routine or calculation routine, if no exposure calculation has been completed, F will import the data from the CCD and then perform the remaining exposure calculations. and then transition from this step to the AP routine.

In step #24, it is determined whether the release switch (S2) is closed, and in step #25, it is determined whether the exposure control value is calculated from the photometry data after focusing. If so, the process moves to an exposure routine and performs exposure control operations.

On the other hand, if the conditions are not met, it is determined whether the photometry switch (Sl) is closed in step #251, and if it is closed, the process returns to the photometry routine, and if it is not closed, the stop routine is executed. perform the following actions.

In the stop routine, first, all flags are reset and the output port (p4) is set to "Low" level.
Sends data to set the display to 0FF (no display) to the display circuit (DSP), stops the motor (MOAF), stops the output of the reference clock (CKOUT), and deactivates the power supply circuit (GV). , set the signal (ADEN) to “Hi”
gh” level, A/D conversion is disabled, and the microcomputer (
COM) stops operating (#26 to #32).

Next, the operation of the AF routine will be explained using FIG. 5.

When the CCD storage operation is completed, an interrupt input signal is input from the ink-face circuit (IFC) to the interrupt input terminal (INTl), and the operation from #39 is performed.
In step 39, it is determined whether or not an interchangeable lens is attached. If it is attached, the process moves to step #40. If it is not attached, the process moves to step #51, which will be described later.
In step #40, data acquisition from D, focus detection, lens drive operation, etc. are not performed.
Analog signals corresponding to the three rows of CCDs output from the interface circuit (IFC) are sequentially A/D converted and taken into the microcomputer (COM), and the flag CF is set to 1, and the flag AEF is set to 1. If the flag AEF is set to 0, it means that the first photometry routine and calculation routine have not finished, so the execution when the return address (I NT) is interrupted is determined. Return to step). Then, when the photometry routine and calculation routine are completed, CF=1 is determined in step #23, and the process returns to the AP routine. If AEF=1 in step #42, the process moves to the AP routine immediately after the capture of CCD data is completed.

In the AF routine, first set the flag CF to O,
It is determined whether AFAVO>K2.

Here, K2 indicates the limit aperture value that allows focus detection by the light receiving section 16a, and when AFAvo>K2, focus detection is impossible for all the light receiving sections 16a to 16c, so the process moves to step #51. On the other hand, AFAvo≦2
If so, then it is determined whether AFAvo>K<. + indicates the limit aperture value that allows focus detection by the light receiving sections 16b and 16c, and AFAvo>K1, that is, <AFA
If vo≦2, only focus detection by the light receiving section 16a is possible, so the process moves to step #48.

If AFAVO≦Kl, it is possible to detect focus in the entire range of aperture values.Next, it is determined whether focus detection is possible off-axis.For example, when the exit pupil position is close, the aperture value This is because off-axis focus detection may not be possible even if the light is bright. At this time, focus detection is performed only on the light receiving section 16a, or - if focus detection is possible off-axis, focus detection is performed on all the light receiving sections 16a to 16c.

Then, it is determined for each light receiving section (focus detection area) whether reliable data is obtained, and if all the data is unreliable, the process moves to step #51 (#4
9. In steps #50) and #51, the flag lFF2 is set to 1. This is so that when focus detection is impossible, exposure control operations can be performed regardless of whether or not focus is achieved.

Then, a warning is displayed that detection is impossible, and C
The CD storage operation is started, the interrupt by INT is enabled, and the process returns to the return address in the photometry routine and calculation routine.

If it is determined in step #50 that at least one piece of reliable data has been obtained, the process moves to step #60 and performs statistical processing. When multiple data are within a predetermined defocus amount, there are processes such as adopting a defocus amount that will bring the multiple subjects within the depth of focus, and then using statistical processing to determine the defocus amount. It is determined whether the defocus amount is within the focus area, and if it is outside the focus area, the process moves to step #62, and if it is within the focus area, the process moves to step #70. In step #62, the defocus direction is displayed,
Multiply the defocus amount by the conversion coefficient (K) to calculate the drive amount of the lens drive motor (MOA F >) #63
), preset this drive amount in the event counter (EVC) (#64), and enable event counter interruption #65),
AF) is operated (#66>.

Then, the process returns to the return address of the photometry routine and calculation routine. Thereafter, while driving the lens, the photometry routine and the calculation routine are repeated, and the pulse from the encoder (ENL) that monitors the amount of lens drive is sent to the selector (S
The data is input to the event counter from the terminal (CNTR) via the terminal (EC), and the contents of the event counter are decremented.

When the content of the event counter becomes O, the interrupt caused by the event counter (EVC interrupt) becomes low, and #10 in Figure 6
In step #100, which performs the operation from step 0, it is determined whether AF is in progress. In this case, since AF is in progress, the process moves to step #1o1, and the motor (M
OAF) is stopped, and in order to perform focus detection for confirmation, the CCD accumulation operation is started (#102), and after enabling interrupts from the interrupt input terminal INT (#103), The photometry routine starts from the start in #7. Note that step #104 will be described later.

In the flow shown in FIG. 5, when it is determined that focus is achieved at step #61, the process moves to step #70, where the in-focus display is performed, and the flag IF is set at step #71.
Set F to 1 and proceed to the photometry routine from step #7. Therefore, once the in-focus state is confirmed, as long as the photometry switch (S,) is closed,
Focus detection and lens driving are not performed.

At step #24 in Figure 4, release switch (S2
) is closed, and the flag I F F is closed in step #25.
If 2 is set to 1, the process moves to the exposure control routine shown in FIG. First, set the AP display to 0 in step #75.
FFL, use the release magnet (RL) at step #76.
M) to start the operation of the exposure control mechanism. Then, it is determined whether an interchangeable lens is attached and whether a reflective telephoto lens is attached (#77, #78) L
If no lens is attached or a reflective telephoto lens is attached, the process moves to step #83 and no aperture control operation is performed.On the other hand, if a normal lens is attached,
First, in step #79, it is determined whether the control aperture value (Av) is equal to the open aperture value (Avo) or not, and Av=Av
If o, the process similarly moves to step #83. on the other hand,
If Av, j= Avo, then the number of refinement stages (Av −
Avo) is set to the event counter (EVC), the port (p,) is set to "High" level, and the pulse from the encoder (ENAP) that monitors the aperture amount is output from the selector (SEC). #80
．． #81. #82), and #83. Wait for a certain period of time in step #84. During this time, the narrowing down operation is performed.
When the event counter interrupts, the aperture magnet (APM) is operated to stop the aperture in step #1o4. Then, after a certain period of time has elapsed, the reflection mirror has finished rising, and the front curtain magnet (ICM) is operated to start running the front curtain and count the exposure time (#85, #86). , when the count is finished,
Operate the leading curtain magnet (2CM) to start running the trailing curtain (#87), and wait for the running of the trailing curtain to be completed and the reset switch (S3) to be turned ON (#8
8. ), reset) - When the switch (S, ) is turned on,
Operate the charging motor (MQC) () to wind the film and charge the exposure control mechanism, and wait for this operation to be completed and the reset switch (S,) to turn OFF (#89.# 90), and when the reset switch (S,) turns OFF, wait until the release button is released and the metering switch (S,) turns OFF (#91), and the metering switch (S,) turns OFF. When this happens, a stop routine is performed, and then the photometry switch (Sl) is turned on and the operation is stopped until the microcomputer (C0M) is activated.

In the above embodiment, an on-axis ranging frame A and an off-axis ranging frame B, C are provided as ranging frames, and each ranging frame A, B, C is assigned to a ranging area I to ■. Although the distance measurement frames are divided into areas, for example, only the distance measurement frames A and B or only the distance measurement frames A and C may be used.
Further, it is also possible to divide the range-finding frame A into areas as in the embodiment, with only the range-finding frame A, or to provide three range-finding frames A, B, and C and set the range-finding frame A as the range-finding frame A. It may be configured such that the distance measurement frames B and C are not divided into regions.

As exposure control modes, only P mode (program exposure mode) is shown, but A mode (aperture priority AE mode), S mode (shutter speed priority AE mode),
Even in M mode (manual mode), when a reflective telephoto lens is attached, it is different from a normal lens, but it requires some handling.

In other words, in A mode, the exposure time is automatically set for a fixed aperture, just like in P mode, and S
mode or M mode, the aperture is fixed and the exposure time is set.

肱-1 As described above, according to the present invention, the aperture value used for determining whether or not focus detection is possible with a reflective telephoto lens is set to the aperture value determined by the outer rays when there is no clarification of the inner rays due to the secondary mirror of the reflective telephoto lens. Since the aperture value is used, it is possible to easily and accurately determine whether focus detection is possible.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the optical system of a focus detection device to which the present invention is applied, Fig. 2 is a diagram showing the principle of the present invention, and Fig. 3 is a diagram showing the overall circuit configuration of a camera system according to an embodiment of the present invention. The block diagrams shown in FIGS. 4 to 6 are flowcharts showing the operation thereof. : Focus detection device, : Lens ROM Applicant: Minolta Camera Co., Ltd.

Claims (1)

[Claims] Reflective telephoto lenses are interchangeable lenses that can be attached to and removed from a camera body that has a built-in phase difference detection type focus detection device, store lens information including an aperture value for determining focus detection in ROM, and output this information to the camera body. A reflective telephoto lens capable of outputting lens information, characterized in that an open aperture value determined by an outer ray of the reflective telephoto lens is stored in a ROM as an aperture value signal for determining whether or not focus detection is possible.