JPS63286833A - Lens exchangeable exposure control system and interchangeable lens - Google Patents

Abstract

PURPOSE:To prevent the drastic restriction of function provided in a camera body by providing a means for discriminating the mounting of a reflecting telephoto-lens, computing an exposure time by executing the arithmetic operation of exposure in case an interchangeable lens is not mounted at the time of mounting the reflecting telephoto-lens and displaying the exposure time and an open iris value from the interchangeable lens. CONSTITUTION:When the reflecting telephoto-lens ML is mounted, the computation of exposure in case the interchangeable lens 11 is not mounted is executed so as to compute only the exposure time Tv in an exposure arithmetic means 2 and the exposure time Tv from the exposure arithmetic means 2 and the open iris value Avo from the interchangeable lens 11 are displayed on an exposure display means 3. When usual interchangeable lens 11 is mounted, the arithmetic operation of exposure using the data of the open iris value Avo from the interchangeable lens 11 is executed in the exposure arithmetic means 2 and the iris value Av from the exposure arithmetic means 2 and the exposure time Tv are displayed on the exposure display means 3. Thus the restriction in case the reflecting telephoto-lens is used as the interchangeable lens can be reduced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an interchangeable lens exposure control system and an interchangeable lens, and is particularly applicable to exposure control of a single-lens reflex camera that includes a reflective telephoto lens in the interchangeable lens group. It is suitable.

(Prior Art) Conventionally, single-lens reflex cameras equipped with TTL AE and AF functions have been put into practical use. In addition, as interchangeable lenses for this purpose, many lenses have been developed in which AE and AF amount related information is fixedly stored so that it can be read from the camera body.

In such a single-lens reflex camera, it has been proposed to perform exposure control using an aperture metering method when it cannot be confirmed that an interchangeable lens is attached, but this does not assume that a reflective telephoto lens is attached.

(Problems to be solved by the invention) Equipped with TTL AE and AF functions as described above 1
In an eye-reflex camera, it is not assumed that a reflective telephoto lens is used as an interchangeable lens, mainly due to focus detection constraints.Therefore, exposure control corresponding to a reflective telephoto lens is not considered either.
Reflective telephoto lenses that can be attached to reflex cameras are also commercially available, but when this lens is attached, the camera body cannot read the necessary information from the interchangeable lens, so of course the camera body does not perform focus detection. Exposure control also operates when no interchangeable lens is attached, so when using a reflective telephoto lens, there is a problem in that the functions provided by the camera body are significantly restricted.

The present invention has been made in view of these points, and its purpose is to provide an exposure control system with fewer restrictions and an interchangeable lens therefor even when a reflective telephoto lens is attached as an interchangeable lens. It is in.

(Means for Solving the Problems) In the lens interchangeable exposure control system according to the present invention, as shown in FIG. If it is not determined whether the reflective telephoto lens ML is attached, an exposure calculation is performed using the data of the open aperture value Avo from the interchangeable lens 11, and if it is determined that the reflective telephoto lens ML is attached, it is replaced. Exposure calculation means 2 calculates only exposure time TV by performing exposure calculation when lens 11 is not attached, and aperture value Av and exposure time Tv from exposure calculation means 2 when it is not determined whether reflective telephoto lens ML is attached. Reflective telephoto lens ML
The lens is equipped with an exposure display means 3 which displays the exposure time Tv from the exposure calculation means 2 and the open aperture value Avo from the interchangeable lens 11 when it is determined that the lens is attached.

In addition, the interchangeable lens according to the combined invention includes a reflective telephoto lens ML, a storage means 4 that fixedly stores data specific to the reflective telephoto lens ML, and a read signal input means 5 that inputs a read signal from the body. and data sending means 6 for sequentially sending data from the storage means 4 to the body based on the read signal, and the data stored in the storage means 4 includes an open aperture value Avo and a maximum aperture value Avmax. , and this open aperture value Avo and maximum aperture value Avmax
are characterized by having equal data.

(Function) In the lens interchangeable exposure control system according to the present invention, the interchangeable lens 11
Discrimination means 1 for determining whether 1 is a reflective telephoto lens ML
is provided, and when the reflective telephoto lens ML is attached, exposure calculation and exposure display are performed in a different manner from when the normal interchangeable lens 11 is attached. That is, when the reflective telephoto lens ML is attached, the exposure calculation means 2 calculates the exposure when the interchangeable lens 11 is not attached, and only the exposure time TV is calculated, and the exposure display means 3 calculates the exposure time TV. Exposure time Tv from calculation means 2 and open aperture value Av from interchangeable lens 11
Display o. In addition, when the normal interchangeable lens 11 is attached, the exposure calculation means 2
The exposure display means 3 displays the aperture value AV and the exposure time Tv from the exposure calculation means 2. Therefore, even when the reflective telephoto lens ML is attached, exposure calculation is performed, and the exposure time Tv and aperture value Av are both displayed according to the results, so it is normal to replace the reflective telephoto lens ML. Compared to the t% meeting using Lens 11, there is no difference in usability.

In addition, the interchangeable lens according to the combined invention is provided with a storage means 4 that fixedly stores lens-specific data, and the data is stored by the data sending means 6 based on the read signal inputted from the body by the read signal input means 5. It is similar to a normal interchangeable lens in that it has the function of sequentially transmitting data from the means 4 to the body, but in addition, data on the open aperture (ii A v o and the maximum aperture value Avmax) stored in the storage means 4 are stored in the storage means 4. Since we set them as equal data, let's turn on the body side,
By detecting that Avo=Av import a×,
It is possible to determine that this interchangeable lens is a reflective telephoto lens ML.

(Example) Fig. 2 is a diagram showing a schematic configuration of a multi-point distance measurement module installed in a single-lens reflex camera. , 15 is a focus detection optical system. 22 is a field stop arranged near the focal plane, and has a rectangular opening 22a,
22b and 22c. 21a, 2 lb, 21
c is a condenser lens, 20 is a module mirror, 18
a, 18b, 18c are separator lens pairs, 16a
, 16b, and 16c are CCD image sensor arrays arranged on the focal plane 17 of the separator lens. Reference numeral 19 denotes an aperture mask, which has circular or oval openings 19g, 19b, and 19c. The image whose field of view is limited by the rectangular opening 22J1 passes through the condenser lens 21m, and is projected as two images onto the CCD image sensor array 16a by the field stop 19a and the separator lens pair 18a. When the distance between these two images is a predetermined distance, it is determined that the image is in focus, when it is narrower than the predetermined distance, it is determined that the front focus is on, and when it is wider than the predetermined distance, it is determined that the rear focus is on.

Similarly, the images of the field stops 19b and 19c are the condenser lenses 21b and 21e and the separator lens pair 18b.

18c onto the CCD image sensor arrays 16b and 16c.

FIG. 3 shows a focus detection optical system 15a (a combination of a condenser lens 21m, a separator lens pair 18g+, and a CCD imaging probe array 16a) located above the optical axis 2 in FIG.
, and a focus detection optical system 15b (a combination of a condenser lens 21b, a pair of separator lenses 18b, and a CCD image sensor array 16b) that are not on the optical axis 2. The distance measurement frames A and B are the focus detection frames shown on the film isometric plane F. Hereinafter, A will be referred to as an on-axis ranging frame, and B will be referred to as an off-axis ranging frame. In addition, ranging frames A and B are projected onto the object surface via the photographing lens 11, and A' and B will be referred to as ranging frames A' and B. '. On the exit pupil plane of the photographic lens 11, the separator lens pair 18a in the focus detection optical system 15a located on the axis is connected to the condenser lens 21.
The images projected by m are shown at 11a and llb. Furthermore, images of the separator lens pair 18b in the off-axis focus detection optical system 15b projected by the condenser lens 21b are shown by llc and lid.

Figure 4 shows the exit pupil aperture of the photographing lens at any exit pupil position of the photographic lens and the focus detection optical system.
FIG. 3 is a diagram generally showing the positional relationship of the passband of the F light beam. 5 and 6 are diagrams for explaining AF pupil-related constants, which are determined by the design and arrangement of the focus detection optical system, among the parameters shown in FIG. 4. FIG. 5 shows the focus detection optical system 15a on the optical axis viewed from the direction of the arrow (x) in FIG.
) A similar diagram is obtained when the focus detection optical system 15b outside the optical axis is viewed from the direction. FIG. 6 is a view of the off-axis focus detection optical system 15b viewed from the direction of arrow (x).

Before entering into the following description, various parameters and constants used in FIGS. 4 to 6 will be explained.

In FIG. 4, Pz is the exit pupil position, which means the distance between the film equivalent plane F and the exit pupil plane of the predetermined photographic lens.

Po is the outer exit pupil radius at the exit pupil position if P z, and is hereinafter referred to as the exit pupil outer diameter.

ΔP0 is a parameter for correcting the shape of the outer exit pupil when viewed from a predetermined image height position.Hereinafter, outer exit will be referred to as image height correction data (or r outer image height correction data for short). ”).

Poo is when the photographic lens is a reflective telephoto type.
Exit pupil radius for regulating the inner exit pupil, hereinafter referred to as exit pupil inner diameter, exit pupil outer diameter P0 and exit pupil inner diameter P0
Generally, the positions of the exit pupils are not necessarily the same, but in the following explanation, they are assumed to be at the same position.

ΔPa' is a parameter for correcting the shape of the inner exit pupil when viewed from a predetermined image height position;
This is called inner exit pupil image height correction data (or "r inner image height correction data" for short). The shape of the exit pupil is usually circular in many cases, but as the image height on the film plane increases, the shape becomes close to a two-ellipse as shown by the broken line in FIG. ΔP0 and ΔP0' are parameters for expressing the amount of change in shape.

AFP is an AF light flux region, which enters the focus detection optical system and indicates a pass range of the AF light flux.

In the case of the focus detection optical system 15a located on the optical axis, H indicates the deviation of the AF light flux area AFP from the principal optical axis 2 of the photographing lens, and is set to the deviation HO-0.

ro indicates the size of the AF light flux area AFP at the exit pupil position Pz.

d is the two AF light flux areas A at the exit pupil position rIIP z
This distance @d, which represents the distance between FPs, is a quantity that affects the detection sensitivity of the focus detection optical system, and is the distance d.

If the value is large, the focus detection sensitivity will be high, but a photographic lens with a small exit pupil diameter cannot be used.

Δd represents the amount of blur in the AF light flux area AFP in the focus detection optical system.

OUT is the outer pupil margin that the light flux entering the focus detection optical system has with respect to the photographing lens, and is expressed by the following formula %Equation % In particular, in the case of the focus detection optical system 15a on the axis, normally H
,=O1ΔP0=0, and 0UTz=P, -ro-d, -Δd/2.

IN is the inner pupil margin when the photographic lens is a reflective telephoto type, and is expressed by the following formula.

IN=((H6+APo')2+(do-Ad/2)"
l""-re-Po" Especially in the case of the on-axis focus detection optical system 15a, H0=0
, ΔPo==0, and INz=d0−Δd/2−ro−p0′. Depending on the sign of the outer and inner pupil margins jLOUT and IN,
Selection of a distance measurement frame and selection of a distance measurement area within the distance measurement frame, which will be described in detail later, are performed.

Next, in FIG. 5, a is the distance from the condenser lens 21a to the isoinclined plane F of the film.

Then, from condenser lens 21 & separator lens 1
8a (or the aperture mask 19a that is closest to the aperture mask 19a).

Ps is a position where an image (hereinafter referred to as "AF pupil") of the separator lens 18a (or the aperture mask 19a immediately adjacent thereto) by the condenser lens 21a is projected, and hereinafter this is referred to as the AF@ position. .

O9 is a point on the optical axis in WPs at AF@ position, and Qs
Qs' opens the AF pupils.

The AF pupil position Ps and the AF pupil aperture QsQs' are
The power of the condenser lens 21a and the aforementioned distances a and t
It is uniquely determined by design. Therefore, the distances 0sQs' and 0sQs from the point O3 on the optical axis to the farthest point Qs and the nearest point Qs' of the AF pupil aperture QsQs' can be regarded as constants. Furthermore, the size e of the ranging frame on the film iso-inclined plane F, and the inclination ω that the principal ray in the on-axis focus detection optical system 15a has with respect to the principal optical axis 2 of the photographing lens,
Determined by design.

Incidentally, the amount of blur Δd in the AF beam area AFP explained in FIG. 4 is Δd> when the exit pupil position is farther or closer than the conjugate position of the separator lens or aperture mask predetermined by the focus detection optical system. It becomes O. This will be explained using FIG. 5. Separator lens 18a
If we sequentially follow the light rays from
When Ps, each light ray shown by a dashed line, a solid line, and a broken line exiting from the center point R of the separator lens 18a passes through one point Rs=Rs', and the amount of blur Δd=o.

Furthermore, when the exit pupil position Pz of the photographing lens is closer to the AF pupil position Ps (Pz=Pz+<Ps), the light ray shown by the solid line coming out from the center point R0 of the separator lens 18a is at the point R1. The ray shown by the broken line passes through point R1
°, and the ray indicated by the dashed-dotted line passes through the middle,
The amount of blur Δd>O. When the exit pupil position Pz of the photographic lens is located at a point farther than AF @ position 771 Ps (P
z = P z2 > P s), separator lens 1
The ray shown by the solid line coming out from the center point R0 of 8a is the point R2
', the light ray indicated by the broken line passes through point R2, and the light ray indicated by the one-dot chain line passes through the middle, and again, the blur amount Δ
d>O. Note that here, in order to simply represent the relationships among various parameters, it is assumed that the AF light flux regulation mask (aperture mask) of the focus detection optical system is circular;
Generally, it does not have to be circular.

Next, in FIG. 6, θ is the off-axis focus detection optical system 15.
The inclination of the principal ray 1p with respect to the principal optical axis 2 at b, h is the amount of deviation of the off-axis distance measuring frame from the principal optical axis 2, and these also differ from the CCD image sensor array 16b and the separator lens 18b.
Since it is determined in design by the geometric arrangement of the aperture mask (and the aperture mask b closest to it) and the condenser lens 21b, it becomes a unique constant once the design of the camera body is completed.

Using the above constants, the parameter j' explained in Figure 4
The expression ro+ro+do is as follows.

First, the amount of deviation F1° of the AF light flux area AFP from the principal optical axis 2 of the photographing lens is expressed as: Ho=1+-(Pz+a)tanθ. Here, the deviation mh of the distance measuring frame from the principal optical axis 2, and the slope F of the film from the condenser lens 21a.
gia, the inclination θ of the principal ray ip with respect to the principal optical axis 2
As mentioned above, is body information and is a constant. The exit pupil position Pz is lens information and differs for each lens.

The size of the AF beam area AFP at the exit pupil position Pz is expressed as ro=l0Q-OQ'l/2.Here, 0 is a point on the optical axis at the exit pupil plane TIPz. , Q is the point furthest from the optical axis of the AF beam area AFP on the exit pupil plane 31 P z, and Qo is the point closest to the optical axis of the AF beam area AFP on the exit pupil plane 'IIP z.

When Pz=Pz, ≦Ps, in FIG.
When Pz-=Pzz>Ps, in FIG. 5, furthermore, the distance Ndo between the AF light flux areas AFP is expressed as follows.

In each of the above equations, 0sQs, 0sQs', Ps, and e are all body constants and are constant. Also, Pz
=Pzl+Pzx has a value "C-" specific to each individual lens.

As is clear from the above, the outer and inner pupil margins OUT and IN are a series of body constants Os Q s .

0!3Qs', Ps, e and a series of lens information Pz, P
,,P,'.

ΔP0. It is expressed as ΔP0゛. By setting appropriate thresholds for the outer and inner pupil margins OUT and IN, selecting the distance measurement area within the on-axis and off-axis distance measurement frames,
Alternatively, it is possible to select a distance measurement frame when there are a plurality of distance measurement frames. To select the distance measurement area or distance measurement frame, select the outer and inner pupil margins OUT within the camera body.

Pz and P based on the method of calculating IN using the above-mentioned calculation formula and the result of the calculation in advance. , Po“, T5o.

One possible method is to prepare a table in the camera body for selecting a distance measurement area by setting an appropriate threshold value for p0', but the following explanation will be based on the latter perspective.

First, an example of distance measurement area selection using a distance measurement frame located on the optical axis will be given.

Figure 7 shows the focus detection optical system 15m on the optical axis.
Various injections of the cladding situation of the luminous flux 1! Poa.

Poa'; pob, pOb'; Poc, Poc'
; pOcj and pOcl' are shown for a photographic lens. Here, the exit pupils p Ob, P ob+
It is assumed that QsQs' corresponds to the AP pupil aperture QsQs' in FIG. Distance A on film iso-inclined plane F. B, A A + B + and A are formed on the CCD image sensor array by the condenser lens 21a and the separator lenses 18a+, 18a2.
It is imaged as z B 2. Point A on the CCD image sensor array
Considering the passband of light incident on I, B + , A z , B 2, the light incident on point A is LAI~
UAI, the light incident on point B1 is LBI~UB1, point A2
It can be seen that the light incident on point B2 has a passband of LA2 to UA2, and the light incident on point B2 has a passband of LB2 to UB2. AF@
[Injection consistent with mouth Q s Q s' @p, b, r'
, b', as a matter of course, no cladding of the AF light beam occurs.

FIG. 8 shows the exit pupils P Oa, P oa'; p ob,
P 6b';p ,,(!.

In FIG. 8, which shows the element surface illuminance distribution on the CCD image sensor array corresponding to P, c'; Pad, Pod', the horizontal axis indicates the direction in which the elements of the CCD image sensor array are arranged, The vertical axis indicates the illuminance on each element surface. It is assumed that images A and B are formed on the right image sensor row R, and images A2l32 are formed on the left image sensor row. The left image sensor row is divided into four ranging areas I to ■.

When using a photographic lens with exit pupils p, b, p, b', the inner exit @p is determined by the outer exit pupil P0b.
, b' does not cause cladding of the AF light flux, so
The element surface illuminance distribution becomes a uniform distribution E.

Therefore, in this case, all distance measurement areas 1 to 2 can be used.

Exit pupil P. When using a photographic lens with a, P 6m'', U
Since cladding occurs in the light flux of A2 and the light flux of UBI, the illuminance on the element surface near the optical axis Z decreases, resulting in a distribution J. Furthermore, since cladding occurs in the light flux of LB2 and the light flux of LAI due to the inner emission @Poa', the illuminance of the element surface far from the optical axis 2 also decreases, resulting in a distribution G. Therefore, the distance measurement area that can be used without being affected by the cladding of the AF light beam is ■.

Exit pupil P. c, when using a photographic lens with Poc', the outer exit pupil P6c separates the luminous flux of U132 and U
Since cladding occurs in the AI light flux, the illuminance on the element surface far from the optical axis 2 decreases, resulting in a distribution like G. Also, due to the inner emission 111POc', the luminous flux of LA2 and LBl
Since cladding occurs in the light beam, the illuminance on the element surface near the optical axis 2 also decreases, resulting in a distribution J. Therefore, A.F.
The distance measurement area that can be used without being affected by the cladding of the luminous flux is ■
It is.

When using a photographic lens with exit pupils P Od, P and d', a large deviation occurs between the light flux of UB2 and the light flux of UAI due to the outer exit @P and d, so the optical axis 2
The illuminance of the element surface far from the area is greatly reduced and becomes like the distribution H, and therefore the distance measurement area I.

■ and ■ cannot be used. Also, the inner exit pupil P. d' causes cladding in the LA2 and LBI luminous fluxes, so the illuminance on the element surface near the optical axis 2 also decreases, resulting in a distribution J, and therefore, the distance measurement area (■) cannot be used either.
In the end, there is no usable ranging area.

From this, tables such as Tables 1 to 4 can be created.

(Leaving space below) Table 1 (Selection table of on-axis distance measurement area from exit pupil position and exit pupil outer diameter) In the above table, Pz: Exit pupil position P s: A F pupil position Po: Exit pupil outer diameter■ ~■: Distance measurement area ×: Distance measurement impossible Table 2 (selection table of on-axis distance measurement area from exit pupil position and exit pupil inner diameter) In the above table, Pz: Exit pupil position P s: A F pupil position P0゛: Exit pupil inner diameter ■ ~ ■: Distance measurement area P s: A F pupil position po: Deformed exit pupil outer diameter ■~■: Distance measurement area In the table, Pz: Exit pupil position Ps: AF pupil position p. ' : Deformed exit pupil inner diameter ■ ~ ■ : Distance measurement area show. In Table 1, r, n, m, and rv indicate ranging areas. × indicates that the illuminance distribution has a large degree of curvature, making distance measurement impossible. Po+ to P64 and Pz+ to Pz4 are predetermined constants obtained from the above calculation formula. Exit pupil P mentioned above. b corresponds to the case of Pz=Ps, Pob-Os Q s, exit pupil P, a is Pzs<Pz<P 241
If P ox< P *a< P o4, the exit pupil P
. c is Pz, <Pz<Pzz+Pol<Poc<Pot
In the case of injection [11Pod is P z< P Z+ ,
This applies when P OIJ < P o+.

The selection of the distance measurement area for the non-reflective telephoto type can be made from this Table 1.

Table 2 shows an example of a distance measurement area selection table in the on-axis distance measurement frame from the exit pupil position Pz and the exit pupil inner diameter P0''. , P
This applies to the case ob'=OsQs', and the injection @P o a
' is Pzz<Pz<Pzs, Pa*'<Poa'<P
If a<', exit pupil P. C+ is PZI<PZ<PZ
21 When POI'<P ocl<P O2°, the exit pupils p and d' are Pz<Pz+.

P, d'< P. This applies to case 1. In the case of reflex telephoto type, is there a prescribed ejection position? ! ! At Pz, select the distance measurement area from the exit pupil outer diameter P0 using Table 1, and select the distance measurement area from the exit pupil inner diameter P0' using Table 2, and select the common distance between the two selected This is the final determination of the distance measurement area.

Table 3 shows the exit pupil position Pz and the modified exit pupil outer diameter p.

This is an example of a distance measurement area selection table in an off-axis distance measurement frame from . Deformed exit pupil outer diameter β. is the exit pupil outer diameter P when viewed from on-axis (or near the on-axis).

, external image height correction data ΔPo, and a body constant partially related to the pupil position Pz, it is approximately determined by the following formula.

P o −P o k ・ΔPa (0≦≦
1) Here, in FIG. 6, the principal ray Ilp of the AF light flux
Assuming that the position where Pz intersects with the optical axis 2 is Pz=Ps (AP@position, constant), when Pz=Ps is near, then =
o, which indicates that the AF light beam is not deviated from the main optical axis 2, and at the most Kuraray position, ΔP0
This shows that there is no influence of P z (see Figure 4).
When < P s or when Pz > PS, k
approaches 1.

1/R, the AF light flux area AFP of the off-axis distance measuring Freno\ is:
Since it deviates from the optical axis 2, k is a parameter that changes from 0 to 0.8. The meaning of the value itself is the AF light flux area AFP of the focus detection optical system located off the optical axis, and the exit pupil outer diameter P at the exit pupil position Pz, which is significantly different from the AF pupil position Ps. This is a coefficient for changing the weighting of ΔP0 when considering the margin with respect to ΔP0.

The modified exit pupil outer diameter p0 defined in this way is used only in the off-axis distance measurement frame 11 to determine the distance measurement area. An example of this is shown in Table 3. The major differences from the selection of the distance measurement area in the on-axis lateral pressure frame shown in Table 1 are: ■For a photographic lens with a small exit pupil position Pz,
Even if the modified exit pupil outer diameter p0 is large, the AF light flux is likely to be blurred.

■Furthermore, even for a photographic lens whose exit pupil position Pz deviates significantly from the AF pupil position, the AF light flux will deviate greatly off-axis as shown in Figure 6, and the k value itself will become large. The problem is that the luminous flux tends to become blurry.

Exit pupil inner diameter P for selecting off-axis ranging area. ′ is also the modified exit pupil inner diameter P. ', P o' = P
o'+ is defined as '·ΔP0° (0≦≦1), and the above P.

A similar argument can be made by replacing p0゛ with p0゛. Table 4 is an example of a table for selecting a distance measurement area in an off-axis distance measurement frame from the exit pupil position Pz and the modified exit pupil inner diameter p0''.

FIG. 9 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 1 in Fig. 2
It has CCD image sensor arrays indicated by 6a, 16b, and 16c. (IFC) is an interface circuit that controls the operation of the CCD image sensor array, A/D converts the signals read out from the CCD image sensor array, and sends the signals to the microcomputer (COM>) through the data bus (DBAF>). It also has a function to transmit the end of the charge accumulation operation of the CCD even element row to the interrupt input terminal (INT, ) of the microcomputer (cOM).The charge Nm time to the CCD image sensor row is determined by the subject. It is controlled by the output of a light receiving section (not shown) that monitors the brightness of the light.

(MOAF) is the lens drive motor for AF, (MDA> is the motor control circuit, and the microcomputer (CO
Forward rotation, reverse rotation, brake, and OFF control are performed using signals from output ports (po) and (p+) of M). (DPA)
are microcontroller (CoM) output ports (1) 2), (+)
:1) This is a display unit for displaying the direction of movement of the lens, focusing, and a warning that focus cannot be detected, based on the signals from (l).

(ENL) is an encoder that outputs pulses to monitor the amount of lens drive (motor rotation amount) by the lens drive motor (MOAF), and (ENAP) outputs pulses to monitor the amount of aperture of the lens. It is an encoder. (SEC) means that the output port (p,) is “
When the level is “Low”, the AF encoder (EN
This is a data selector for sending pulses from the diaphragm encoder (ENAP) to the event counter input terminal (CNTR) when the signal is at the "'Higb" level. An event counter is provided inside the microcomputer (COM), data is preset in the event counter, and the terminal (CNTR)
The contents of the event counter are counted down when a pulse can be input to, and when the contents of the event counter reach O, an interrupt is generated.

(Sl) is a photometry switch that is opened at the first step of pressing the release button, and the opening signal of this photometry switch (Sl) is sent from the interrupt input terminal (INTO>) of the microcomputer (COM).
is input to the input boat (p,). (S2) is a release switch that is closed at the second step of pressing the release button, and the opening signal of this release switch (S2) is input to the input port (pg). (S3) is a reset switch that is closed upon completion of the exposure control operation and opened upon completion of winding/charging, and 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 capacitor (+ld) is at "Low" level.
High voltage (HV) and low voltage (BA) based on the output of
LV). High voltage (HV)
) and interface circuit (IFC).

In addition, the low voltage (LV) is the display unit (DPA), encoder (ENL), (ENAP), data selector (
SEC), and the film sensitivity reading circuit (ISD) described below.
'), lens circuit (LEC), photometry and A/D conversion circuit (MEC), decoder/driver (DDR), and serves as a power source for the motor control circuit (MDA), (MDF),
The display unit (DSP) and microcontroller (COM) are powered by batteries (
Receives power directly from BA) via the power line (EV).

(ISD) is a film sensitivity reading circuit that reads the ISO data on the film container and the sensitivity.
When the film S degree reading circuit selection signal (C9IS) from the output port (pg) goes to "Low" level, the film sensitivity data is sent to the serial input terminal (SIN) in synchronization with the serial clock (SCK) from the microcomputer (COM). )
Send serially to (LEC) is a lens circuit provided within the interchangeable lens. This lens circuit (L E
C) has a circuit configuration disclosed in, for example, Japanese Patent Application Laid-Open No. 59-140408, and has an output port (pl
. ) lens circuit transition selection signal (CSL) is “Low”
When the level is reached, various data stored in the ROM in the lens circuit (LEC) are serially sent to the serial input terminal (S I N) in synchronization with the serial clock (SCIO).Here, the lens circuit ( R in LEC)
The data fixedly stored in the OM will be explained separately for fixed focus lenses and zoom lenses.

(Leaving space below) Table 5 (Memory contents of the ROM inside the lens of a fixed focus lens) Table 6 (Storage contents of the ROM inside the lens of a zoom lens) Table 5 is for a fixed focus lens, and Table 6 is for a zoom lens. The contents stored in the ROM inside the lens are shown. address 0
1 contains the data common to all lenses as the mounting signal (IC).
It is fixedly stored as P). Address 02 contains the open aperture value (A vo), and address 03 contains the maximum aperture value (A vo).
vmax) is fixedly stored. In the case of a zoom lens whose aperture value changes with zooming, the aperture value at the shortest focal length is fixedly stored. Also, in the case of a reflective telephoto lens, the aperture is fixed, so A vo = A v
It is max. Data of focal pressure ta <n is stored at address 04 in the case of a fixed focus lens, and at addresses 10 to IF in the case of a zoom lens. In addition, in the case of a zoom lens, the lower 4 of 10 or more addresses
Bits 0-F are addressed by the signal obtained from the zoom encoder in response to zooming. At address 05 or addresses 20 to 2F, there is a coefficient (
K) is stored. address 06 or address 30
~3F stores data on the amount of aperture change (ΔAv) associated with zooming, and in the case of a fixed focus lens, ΔAv
=O. address 07 or address 40-4
Data on the exit pupil position (Pz) is stored in F, and data on the exit pupil outer diameter (Po) is stored in address 08 or addresses 50 to 5F. Address 09 is the exit pupil inner diameter (Poo
) is stored, and is Poo-○ for lenses other than reflective telephoto lenses. Address OA or addresses 60 to 6F store external image height correction data ΔP0, address OB stores internal image height correction data ΔP0°, and for lenses other than reflective telephoto lenses, internal image height correction data ΔP0° =0.

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

(M E C) is a photometry and A/D conversion circuit, and when low voltage (LV) power supply from the power supply circuit (GV) starts, it starts photometry operation and outputs (11+2
) A/D conversion enable signal (ADEN) is “Low”
When the level is reached, A/D conversion is delayed at a constant cycle. Then, when the photometry and A/D conversion circuit selection signal (CSME) from the output port (p,) becomes “Low” level, the A/D converted and latched data is synchronized with the serial clock (SCK). Microcomputer (CO)
M). (DDR) is a load driving circuit, which connects the data bus (DBDR) from the microcontroller (COM) to the
It decodes the data sent through the device and drives the load according to the decoding result.

The loads include a release magnet (r(LM)), an aperture control magnet (APM), a leading curtain control magnet (ICM), a trailing curtain control magnet (2CM), and a charging motor for the film advance and exposure control mechanism ( MOCH
) and its driver (MDF>).

X is an oscillator.

The operation of this camera system will be explained below based on the flowcharts shown in FIGS. 10 to 16. In the following description, the symbol "#" means a step number of the program. When the release button is operated, the first press closes the photometry switch (S,), an interrupt signal is input to the interrupt input terminal (INTo), and the microcomputer (COM) Interrupt routine INTO in Figure 10
Start the operation from. First, the power supply control signal (pwc) output from the output port (p,) is set to "Low" level to operate the power supply circuit (GV) (#1)
, Next, the interface circuit (IFC), display circuit (
DSP), outputs the reference clock (CKOUT) to the photometry and A/D conversion circuit (MEC), and performs the COD initialization operation to flush out the charge accumulated in the COD (#2° #3) 0 Next, The charge accumulation operation of the COD is started, and when the charge accumulation operation ends, the interrupt input terminal (INT
, ) can be accepted, and the output port (plz)
The A/D conversion enable signal (ADEN) from the
6).

Next, the process moves to the photometry routine, and lens data is acquired from the interchangeable lens, and film sensitivity data (I) is acquired from the film container.
SO data) respectively (#7, #8), then flag IFF1. Determine the state of IFF2. IFF is a flag that is set to 1 when the in-focus state is reached, and IFFz 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 if it is in focus, the photometric data is captured, and when the data is captured after the focus is focused, the flag I F F z is set to 1, and the calculation routine to move to. If flags IFF, IFF2 are both 1, the process directly proceeds to the calculation routine without inputting photometric data (#9 to #13).

In the calculation routine, first, in step #14, it is determined whether or not the lens attachment signal ICP is input. If so, the process moves to step #15, and if not, the process moves to step #16. In step #15, the open aperture value Avo and the maximum aperture value Avmax are equal (A vo=
= A vmax), and if it is a reflective telephoto lens, then A vo = A v+max, so #16
, A vo *A vmax, it is a normal interchangeable lens, so the process moves to step #19. First, when no lens is attached or when a reflective telephoto lens is attached, aperture control is of course impossible, and the aperture must be regarded as fixed.

Therefore, in step #16, (photometric data) = Bv
The exposure time Tv is calculated by adding the ISO value Sv indicating the film sensitivity to -Av (By is the subject brightness and Av is the fixed aperture value). Then, in step #17, it is determined whether or not a lens is attached, and if a lens is not attached, the exposure time is displayed in step #18, and the F
The value is a warning display (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 (open aperture value Avo =
The maximum aperture value (Avmax) is displayed in step #21. If it is determined in step #15 that it is not a reflective telephoto lens, then in step #19 (photometry data) = Bv
- Calculate exposure value Ev by adding Avo+ΔAv+Sv to (Avo+ΔAv), calculate aperture value Av and exposure time Tv by performing program exposure calculation (#20) based on this exposure value Ev, and display this. (#21).

When the above operations are completed, flag AEF 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, it shifts to the AF cell. This flag C
When the COD charge accumulation operation is completed during 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. This step is provided to proceed from this step to the AF cell.

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, the output port (p,) is set to "Low" level, data is sent to the display circuit (DSP) to set the display to 0FF (no display state B), and the motor is (MOAF), stops the output of the reference clock (CKOUT), makes the power supply circuit (GV) inactive, and outputs the signal (ADEN).
is set to “High” level to disable A/D conversion and the microcomputer (COM) stops operating (#26 to #32)
.

Next, the operation of the AP routine will be explained using FIG. When the N product operation of the CCD is completed, an interrupt input signal is input from the interface circuit (IFC) to the interrupt input terminal (INT), 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 flag AEF is set to O, it means that the first photometry routine and calculation routine have not finished, so the return address (when the INT+ interrupt occurs) is Return to execution 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. #4
If AEF=1 in step 2, the process moves to the AP routine immediately after the capture of CCD data is completed.

In the AF cell, first set the flag CF to 0,
The process moves to subroutine 5UB1 shown in FIG. 13. In this subroutine 5UB1, a distance measurement area where focus detection is possible is selected in the on-axis distance measurement frame A based on the exit pupil position Pz and the exit pupil outer diameter P0.Next, in step #44, the distance measurement area from the lens is selected. Exit pupil outer diameter P0 and outer image height correction data Δ
Off-axis ranging frame B from P0 and camera body constant k
, C, the modified exit pupil outer diameter p0 is calculated. Next, the process moves to subroutine 5UB2 shown in FIG. 14, and a focus detection area is selected from off-axis distance measurement frames B and C based on the exit pupil position Pz and the modified exit pupil outer diameter rIo. do. Next, in step #45, the exit pupil inner diameter P o'
” Determine whether or not O, p o+ =.

If so, it is a normal lens, and the process immediately proceeds to step #47. On the other hand, if P, 1≠0, it is a reflective telephoto lens, and the process moves to subroutine 5UB3 shown in FIG. In subroutine 5UB3, data on exit pupil position Pz and exit pupil inner diameter P are obtained. Based on the data of °, select the distance measurement area where the focus can be detected from the on-axis distance measurement frame A,
The distance measurement area selected in subroutine 5UB1 and also in subroutine 5UB3 is finally determined.Next, in step #46, exit pupil inner diameter P0゛ from the lens and internal image height correction data ΔP0 are determined. The modified exit pupil inner diameter P is calculated from ' and the constant of the camera body. Next, the process moves to subroutine 5UB4 shown in FIG. 16, where the exit pupil position Pz and the modified exit pupil inner diameter P are determined. ', selects a detectable ranging area from the off-axis ranging frame [3, C, and finally determines the ranging area that was selected in subroutine 5UB2 and is also selected in this subroutine 5UB4. do.

In step #47, data Pz, P regarding exit pupils are
Based on o, Po'+Po+f'o', it is determined whether or not there is any selected distance measurement area. If there is no selected distance measurement area, focus detection is not performed and the process moves to step #51. on the other hand,
If at least one ranging area is selected, focus detection (defocus amount detection) is performed for each selected ranging area (#48), and reliable detection is performed for each ranging area. It is determined whether data is obtained or not, and if all data is unreliable, the process moves to step #51 (#49, #50). In step #51, the flag IF
Set F2 to 1. This is to enable exposure control operation to be performed regardless of whether or not focus is achieved when focus cannot be detected. Then, a warning message indicating that detection is impossible is displayed, and the CCD storage operation is started.
Allows the interruption and 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. There is processing such as employing a signal, or when a plurality of data are within a predetermined defocus amount, employing a defocus amount such that the plurality of subjects fall within the depth of focus. Then, it is determined whether the defocus amount determined by the statistical processing 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 interrupt #65), and set the lens drive motor (M
OAF) (#66).

Then, the process returns to the return address of the photometry routine and calculation routine. Thereafter, the photometry routine and calculation routine are repeated while driving the lens. In addition, the pulse from the encoder (ENL) that monitors the lens drive amount is transmitted 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 reaches O, an interrupt (EVC interrupt) is generated by the event counter, and #1 in Fig. 12 is generated.
Perform the operation from step 00.

In step #100, it is determined whether AF is in operation or not. In this case, since AF is in operation, the process moves to step #101, the motor (MOA F ) is stopped, and focus detection is performed for confirmation. Therefore, after starting the M product operation of the CCD (#102> and enabling interrupts from the interrupt input terminal INT (#103), the process moves to the photometry routine from step #7. Step #104 will be described later.

In the flow of FIG. 11, if it is determined that the fish is a fish that can be fished in step #61, the process moves to step #70.
Display the goldfish, and set flag I in step #71.
Set FF+ to 1 and proceed to the photometry routine from step #7. Therefore, once the in-focus state is confirmed, focus detection and lens driving will not be performed thereafter as long as the photometry switch (S, ) is closed.

At step #24 in Fig. 10, press the release switch (S
2> is closed and the flag lFF2 is set to 1 in step #25, the process shifts to the exposure control routine shown in FIG. First, set the AF display to 0F in step #75.
FI,, At step #76, release the release magnet (RL).
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 step #79 is performed. Determine whether the control aperture value (Av> is equal to the open aperture value (Avo) or not, A v=A
If it is vo, the process similarly moves to step #83. On the other hand, if A v 4=A v o, the number of refinement stages (A
Set v-Avo) to the event counter (EVC) and set baud) (p+) to the "HiHb" level so that the pulse from the encoder (ENAP) that monitors the aperture amount is output from the selector (SEC). do(
#80. #81. #82), and then wait for a certain period of time in steps #83 and #84. If the narrowing down operation is performed between 4: and an event counter interrupt occurs, #104
In step , the aperture magnet (APM) is operated to stop the aperture. Then, after a certain amount of time has passed,
The reflection mirror has been raised and the front curtain magnet (I
CM) to start running the first curtain and count the exposure time (#85, #86). When the count is finished, operate the second curtain magnet (2CM) and start running the second curtain. (#87), and waits for the trailing curtain to complete running and the reset switch (S,) to be turned on (#88). When the reset switch (S3) is turned ON, the charging motor (MOCH) is operated to wind the film and charge the exposure control mechanism, and when this operation is completed, the reset switch (S,) is turned OFF.
Wait for F (#89).

#90). Then, the reset switch (S,) is turned OFF.
, wait until the release button is released and the metering switch (S,) turns OFF (#91). When the metering switch (S,) turns OFF, the stop routine is performed, and then When the photometry switch (Sl) is turned ON and the operation is stopped until the microcomputer (COM) is activated, the subroutines 5UBI, 5UB2, 5 shown in Fig. 11 are executed.
The specific contents of UB3, 5UB4 are shown in FIGS. 13, 14, 15, and 16, respectively. In the subroutine 5UBi of FIG. 13, the exit pupil position Pz is determined according to Table 1.
A distance measurement area is selected from the on-axis distance measurement frame A based on the exit pupil outer diameter P0. First, in step #110, P,
. KuP. If P o < P o +, there is no detectable ranging frame, and the process moves to step #128.

On the other hand, if P0≧P01, then P in step #111. KuP. 2, and if P 02 > P o≧Pot, Yl is set as the address in step #112.

Thereafter, in the same way, P at step #113. 3〉P0≧P
If it is O2, set Y12 as the address in step #114, and set P 04> P in step #115.

≧P0. If so, Yl is set as an address in step #116, and if P0≧P04 in step #115, Yl is set as an address in step #117.

Next, the exit pupil position fl P z is also determined in the same manner according to Table 1, and in step #118, Pz≧Pz
, then move to step #128, if PZ4>PZ≧Pz3 in step #118, set XI4 as the address in step #120, and if PZ*>Pz≧Pz2 in step #121. , set X13 as the address in step #122, and set Pz in step #123.
If 2>Pz≧Pz, then XI2 in step #124
Set the address to P Z+ in step #123.
> P z, set X11 as the address in step #125. As a result, which position in Table 1 is the address data (X II, Y + +)
This address data (XII
, YII) specifies the ROM table in which Table 1 is stored, and sets the data of the focus-detectable distance measurement area stored therein in the register ERAR. This data is 4-bit data corresponding to the distance measurement areas ■ to ■. The bit corresponding to the distance measurement area where focus detection is possible is 1, and the bit corresponding to the distance measurement area where focus detection is not possible is 0.
It becomes. Therefore, for example, address data (X
+ +, Y + +) is specified, “0001
"or '0011" data, address data (X14
．． Yl,) is specified, “0001” or “100
When the data "1" and the address data (Xll, Yl4) are specified, the data "1111" is set in the register ER/R. Also, in step #128, the distance measurement area where the focus can be detected is set. There is no register ER
“oooo” is set in AR.

The subroutine 5UB2 in FIG. 14 is a flow for selecting a focus detectable distance measurement area from the off-axis distance measurement frames B and C from the exit pupil position Pz and the modified exit pupil outer diameter p0 according to Table 3. . Subroutine 5UB1 in Figure 13
Similarly, when p 0 (f50. in step #130, or when Pz≧Pz4 in step #138, there is no focus detection area, so register ER,
Set 0000'' in BCR.Furthermore, if p.1≦p,<p.2 in step #131, set Y21 as address in step #132, and set P 02≦P o in step #133. (If P 03, set Y2□ as the address in step #134, and set p o3≦p0・<po in step #135, set Y23 as the address in step #136, and set Y23 as the address in step #135. If po, ≦P in step, set Y2 as the address in step #137.Furthermore, in step #139, set Y2 as the address.
If z, ≦P z < P z 4, set X24 as the address in step #140, and if Pz2≦Pz<Pz3 in step #141, set X23 as the address in step #142, Pz in 143 steps
, if ≦PZ<PZ2, X2□ in step #144
Set the address to P Z+ in step #143.
> P z, set X21 as the address in step #145. Then, the set address (X21
1Y21) specifies the ROM table and sets the data stored at that address in the register ERBCH.

In the subroutine 5UB3 shown in FIG. 15, a focus detection area in the on-axis distance measurement frame A is selected from the exit pupil position Pz and the exit pupil inner diameter P0'' according to Table 2, and finally, , selects a distance measurement area in which focus can be detected using the on-axis distance measurement frame A determined from both the exit pupil outer diameter P0 and the exit pupil inner diameter P0'. First, according to Table 2, address data (X31.Y31) is set (#
151 to #166), and this address data (X
:++.

Y, 1) specifies the ROM table, reads the data stored at that address number, and performs the AND of this data with the data already set in the register ERAR in subroutine SUB 1 for each bit. and set this result in register ERAR. by this,
On the other hand, the bit corresponding to the distance measurement area selected is 1.
Even if the other bit is O, that bit becomes O, and the exit pupil outer diameter P. , and the exit pupil inner diameter P0' are set in the register ERAR. Note that p 0+≧P0. ' or Pz<Pz, there is no ranging area where focus can be detected, so the register ERAR
is set to "o o o o".

In subroutine 5UB4 of FIG. 16, according to Table 4, the exit selects a focus detectable distance measurement area from the off-axis distance measurement frames B and C based on the position Pz and the modified exit pupil inner diameter p0'', and selects the distance measurement area in which the focus can be detected. Specifically, the modified exit pupil outer diameter P. and the modified exit pupil inner diameter P. A distance measurement area in which the focus can be detected using off-axis distance measurement frames B and C is selected from both of . First, similar to subroutines 5UB1 to 5UB3 in FIGS. 13 to 15,
Address data (X<+, Y4+) is set according to the size of p, ', Pz, and this address data (X41.Y
41) specifies the ROM table, reads the data stored at this address, and performs the logical product of this data and the data already set in the register ERBCR in subroutine 5UB2 for each bit. By setting in the register ERBCH, the distance measurement area where the focus can be finally detected is set. Note that Po゛≧
p0. ', there is no ranging area where the focus can be detected, so "0000" is set in the register ERBCR.In the above embodiment, the on-axis ranging frame A and the off-axis ranging frame The distance measurement frames A, B, and C are each divided into distance measurement areas ■ to ■. Only frames A and C may be used, or only the distance measurement frame A may be used and the jump measurement frame A may be divided into areas as in the example, or three distance measurement frames A, B, and C may be used. Set up distance measuring frame 2, A
It may be configured such that the inside of the distance measurement frames B and C are divided into regions, but the inside of 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, different measures are required than when using a normal lens. That is, in A mode, the exposure time is automatically set for a fixed aperture as in P mode, and in S mode or M mode, the exposure time is set for a fixed aperture.

In addition, in the description of the above embodiment, in order to determine whether or not the AFLfi function based on the TTL method can be used,
Data regarding exit pupil P S + P o + P o
'+ΔP0. Although an example in which ΔPo' is provided has been shown, these data are omitted, and instead, in the case of a reflective telephoto lens, a signal indicating that focus detection is not possible is provided, and data regarding the aperture is as in the previous embodiment. The configuration may be such that the open aperture value Avo and the maximum aperture value Avmax (=Avo) are sent.

(Effects of the Invention) As described above, the lens exchangeable exposure control system according to the present invention is provided with a discriminating means for determining whether a reflective telephoto lens is attached, so that when a reflective telephoto lens is attached, an interchangeable lens is attached. In this case, only the exposure time is calculated by performing exposure calculations when the lens is not set, and this exposure time and the maximum aperture value from the interchangeable lens are displayed. However, the exposure calculation is performed, and the exposure time and aperture value are both displayed according to the results, making it easier to use than using a regular interchangeable lens. The effect is that there are fewer restrictions when using a telephoto lens, and in particular,
By displaying the open aperture data from the interchangeable lens as the aperture value when a reflective telephoto lens is attached, users can be informed of exposure information in more detail than when nothing is displayed. There are advantages.

In addition, in the interchangeable lens according to the merged invention, the data of the open aperture value and the maximum aperture value are fixedly stored so that they can be read from the body, and the data of the open aperture value and the maximum aperture value are set to be equal data, so that the reflective telephoto lens can be used. Since it is designed to indicate that it is a lens, it is possible to determine whether a reflective telephoto lens is attached without sending extra data compared to a normal lens system, which has the advantage of not being a constraint on the emission of an interchangeable lens system. .

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the present invention, FIG. 2 is a perspective view of a focus detection device used with an exposure control system according to an embodiment of the present invention, and FIG. 3 is a perspective view showing the configuration of the main parts of the same. Fig. 4 is an explanatory diagram of the exit pupil plane of the interchangeable lens used in the above, Fig. 5 is an explanatory diagram of pupil-related constants in the focus detection device of the above, and Fig. 6 is an explanatory diagram of the off-axis focus detection optical system used in the above. ,
Fig. 7 is an explanatory diagram of the axial focus detection optical system used in the above, Fig. 8 is a diagram showing the illuminance distribution on the CCD image sensor array used in the above, and Fig. 9 is a camera system using the exposure control system shown in the above. The circuit diagram and FIGS. 10 to 16 are flowcharts for explaining the operation of the same. 1 is a discrimination means, 2 is an exposure calculation means, 3 is an exposure display means,
4 is a storage means, 5 is a read signal input means, 6 is a data sending means, 11 is an interchangeable lens, and ML is a reflective telephoto lens.

Claims (3)

[Claims] (1) A determination means that determines whether the interchangeable lens is a reflective telephoto lens based on data from the interchangeable lens, and when it is not determined whether a reflective telephoto lens is attached, performs exposure calculation using the maximum aperture value data from the interchangeable lens. , an exposure calculation means that calculates only the exposure time by performing exposure calculation when no interchangeable lens is attached when it is determined that the reflective telephoto lens is attached; It is characterized by comprising an exposure display means for displaying an aperture value and an exposure time, and for displaying an exposure time from an exposure calculation means and an open aperture value from an interchangeable lens when it is determined that a reflective telephoto lens is attached. An interchangeable lens exposure control system. (2) The data from the interchangeable lens includes data on the maximum aperture value in addition to the data on the open aperture value, and the means for determining whether the interchangeable lens is a reflective telephoto lens is based on the open aperture value and the maximum aperture value. 2. The interchangeable lens type exposure control system according to claim 1, wherein the lens exchange type exposure control system is a means for determining that the lens is a reflective telephoto lens when the two lenses are equal. (3) A reflective telephoto lens, a storage means that fixedly stores data specific to the reflective telephoto lens, a means for inputting a read signal from the body, and a means for sequentially sending data from the storage means to the body based on the read signal. the data stored in the storage means includes an open aperture value and a maximum aperture value, and the open aperture value and the maximum aperture value are equal data. lens.