CA2066064C

CA2066064C - Exposure control apparatus of camera

Info

Publication number: CA2066064C
Application number: CA 2066064
Authority: CA
Inventors: Osamu Sato; Satoshi Nakano; Isamu Hirai; Toshiyuki Kitazawa; Takayuki Sensui; Masato Yamamoto; Toshimasa Yamanaka; Takenao Shishikura; Akio Takahashi; Nobuhiko Matsudo
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1991-04-15
Filing date: 1992-04-14
Publication date: 2001-07-31
Anticipated expiration: 2012-04-14
Also published as: FR2675277A1; MY110099A; GB2256060A; GB2256060B; HK36495A; FR2675277B1; CA2066064A1; DE4212660A1; DE4212660C2; AU649804B2; AU1489192A; GB9208332D0

Abstract

An exposure control apparatus of a camera wherein a pair of exposure factors, including a shutter speed and a diaphragm value, can be manually and independently set.
Furthermore, in the exposure control apparatus, an exposure value determined in accordance with the exposure factors can be locked, and one of the exposure factors can be varied, based on the locked exposure value, when the other exposure factor is varied by the associated manual setting means.

Description

EXPOSURE CONTROL APPARATUS OF CAMERA
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to an exposure control apparatus of a camera having a plurality of exposure modes.

2. Description of Related Art In a conventional camera having a plurality of exposure modes, a photographer can select a desired to exposure mode by actuating an associated switch or button, etc.
In a recent camera having modes other than the exposure modes, such as a continuous shot mode, etc., the mode selection is effected by actuating a plurality of switches in combination.
However, ordinary photographers do not frequently use all of the exposure modes. Namely, only a few specific exposure modes are used. Therefore, for ordinary photographers, the need to actuate several switches in 2o combination to select a mode is troublesome and complicated.
Furthermore, in a program exposure mode of a known camera, a shutter speed and a diaphragm value are automatically determined in a certain relationship (combination), and accordingly, it is impossible for the 25 photographer to set optional shutter speed and diaphragm values which do not satisfy the predetermined relationship while in the same mode. For example, when an operation switch is actuated in a program exposure mode of a known camera, both the shutter speed and the diaphragm value are modified simultaneously while maintaining a specific relationship therebetween, and accordingly, it is impossible to vary only the shutter speed or diaphragm value. Consequently, if the photographer wants to vary only the shutter speed or diaphragm value while in the program io exposure mode, it is necessary for the photographer to first switch the program exposure mode to a diaphragm priority automatic exposure mode or a shutter speed priority automatic exposure mode.
Furthermore, in a manual exposure mode of a known camera, the photographer manually sets the optimum shutter speed and diaphragm value, whils= observing an exposure meter provided in a field of view of a finder. Namely, since the photographer manually sets both the optimum shutter speed and diaphragm value by himself of herself, it 2o is possible for him or her to create more artistic or technical pictures.
However, the adjustment of both the shutter speed and diaphragm value is troublesome, especially for the ordinary photographer. In particular, if one of either the shutter speed or diaphragm value is readjusted after the shutter speed and the diaphragm value are adjusted to obtain an optimum exposure value, the other of either the diaphragm value or shutter speed must also be readjusted to maintain the optimum exposure value, which changes as a result of the readjustment.
SUMMARY OF THE INVENTION
The primary object of the present invention is to eliminate the above-mentioned drawbacks of a known exposure control system having a plurality of exposure modes by providing a simple exposure control apparatus in which, if one of the exposure factors (diaphragm value and shutter speed) is varied in the manual exposure mode, the other exposure factor is automatically adjusted so as to obtain an optimum exposure value by a simple operation.
According to an embodiment of the present invention, there is provided an exposure control apparatus of a camera, comprising: means for setting a manual setting mode in which a diaphragm value and a shutter speed are manually settable, the diaphragm value and the shutter speed being settable independently of a luminance of an object to be photographed with the camera; means for locking an exposure value determined in accordance with the diaphragm value and the shutter speed value set in the manual setting mode; and means for varying one of the diaphragm value and the shutter speed based on the locked exposure value, when the other of the diaphragm value and the shutter speed is varied in the manual setting mode so as to maintain constant the locked exposure value.
In accordance with yet another embodiment of the present invention there is provided an exposure control apparatus of a camera, comprising: means for manually setting a diaphragm value and a shutter speed in a manual setting mode of the camera, the diaphragm value and shutter speed being settable independently of a luminance of an object to be photographed with the camera; exposure value storing means for storing a product of APEX values of the manually set shutter speed and the manually set diaphragm value; and means for varying one of the diaphragm value and shutter speed when the other of the diaphragm value and shutter speed is varied by the manual setting means when the product of the APEX values is stored in the exposure value storing means, so as to make a product of the varied diaphragm value and shutter speed equal to the APEX
values stored in the exposure value storing means.
Yet another embodiment of the present invention provides an exposure control apparatus of a camera, comprising: first means for manually setting a shutter speed in a manual setting mode; second means for manually setting a diaphragm value in a manual setting mode, the diaphragm value and shutter speed being independently settable with respect to a luminance of an object to be photographed with the camera; exposure value locking means for fixing an exposure value to a constant value in accordance with the manually set shutter speed and the manually set diaphragm value; and shutter speed varying means for varying, when the exposure value is fixed by the exposure value locking means, the shutter speed in accordance with the fixed exposure value when a diaphragm ring is rotated to vary the diaphragm value so as to maintain the exposure value to the constant value.
A still further embodiment of the present invention provides an exposure control apparatus for a camera, comprising: means for manually inputting a shutter speed and a diaphragm value in a manual setting mode, the shutter speed and the diaphragm value being independently settable with respect to a luminance of an object to be photographed; means for locking an exposure value calculated in accordance with the manually inputted shutter speed and manually inputted diaphragm value; and means for automatically varying one of the shutter speed and diaphragm value after the exposure value is set by the locking means when the other of the shutter speed and diaphragm value is manually changed so as to maintain constant the locked exposure value.
With the above provisions, it is possible for a photographer to vary only the shutter speed or diaphragm value without first switching the program exposure mode to, for example, a diaphragm priority automatic exposure mode or a shutter speed priority automatic exposure mode, and without breaking the predetermined relationship between the values.

4a BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below in detail with reference to the accompanying drawings, in which:
Figure 1 is a plan view of a single lens reflex camera to which the present invention is applied;
Figures 2 and 3 are a back view and a front elevational view of a main part of a single lens reflex camera shown in Fig. 1, respectively;
Figure 4 is a block diagram of a circu it arrangement to of a single lens reflex camera shown in Fig. 1;
Figure 5 is a flow chart of a main operation of a CPU, according to the present invention;
Figure 6 is a timing chart o.f a communication operation between a CPU and an IPU, according to the i5 present invention;
Figure 7 is a flaw chart ~of an automatic exposure mode operation, according to the present invention;
Figure 8 is a flow chart of an error correcting operation, according to the present invention;
2O Figure 9 is a flow chart of a hyper-program exposure mode operation according to the present invention;
Figure 10 is a diagram of a hyper-program exposure mode shown in Fig. 9;
Figure 11 is a flow chart of a limited program 25 exposure mode operation, according to the present invention;

~°'~ ~~ v~~a Figure 12 is a diagram of a limited program exposure mode shown in Fig. 11;
Figure 13 is a flow chart of a hyper-shutter speed priority automatic exposure mode operation, according to the present invention;
Figure 14 is a flow chart of a hyper-shutter speed priority automatic exposure mode operation, according to another embodiment of the present invention;
Figure 15 is a diagram of a hyper-shutter speed priority automatic exposure mode shown in Figs. 13 and 14;
Figure 16 is a flow chart of a hyper-diaphragm priority automatic exposure mode operation, according to the present invention;
Figure 17 is a flow chart of a hyper-diaphragm priority automatic exposure mode operation, according to another embodiment of the present invention;
Figure 18 is a diagram of a hyper-diaphragm priority automatic exposure mode shown in Figs. 16 and 17;
Figure 19 is a flow chart of a LA manual exposure mode operation, according to still another embodiment of the present invention;
Figure 20 is a flow chart of an LM manual exposure mode operation, according to the present invention;
Figure 21 is a flow chart of an LM aperture priority automatic exposure mode operation, according to the present invention;
Figures 22 and 23 are flow charts of an LA bulb and LM bulb exposure mode operation, respectively, according to the present invention;
Figure 24 is a flow chart of an LA hyper-manual exposure mode operation, according to the present invention;
Figure 25 is a view showing an example of a hyper-manual select flag;
Figure 26 is a flow chart of a main operation of an to IPU, according to the present invention;
Figure 27 is a flow chart of a communication operation between an IPU and a taking lens, according to the present invention;
Figure 28 is a flow chart of a switch input operation;
is Figure 29 is a flow chart of a Tv electronic dial operation;
Figure 30 is a flow chart of a diaphragm value AV
changing operation as effected by an Av electronic dial;
Figure 31 is a flow chart of an Av electronic dial 20 operation;
Figure 32 is a flow chart of a shutter speed changing operation as effected by a Tv electronic dial;
Figure 33 is a flow chart of a mode shifting operation;
25 Figures 34A and 34B are together a flow chart of a mode selecting operation;
Figure 35 is a flow chart of a checking operation;
Figure 36 is an example of data storage in a RAM of an IPU;
s Figure 37 is a flow chart of a memory locking operation;
Figure 38 is an example of a memory locking flag in a RAM of an IPU;
Figures 39A, 39B, 39C, 39D, 39E, 39F, 39G and 39H are to flaw charts of an indication operation, according to the present invention;
Figure 40 is a flow chart of an Ev checking operation, according to the present invention;
Figures 41A, 41B, 41C, 41D, 41E, and 41F show an 15 indication of an LCD panel and an indication unit within a finder shown in various initial indication positions;
Figures 42A, 42B, 42C, 42D, 42E, 42F, 42G and 42H
show various exposure modes indicated on an LCD panel and an indication unit within a finder;
2o Figures 43A, 43B and 43C show various exposure modes in a lens manual mode, as indicated on an LCD panel and an indication unit within a finder;
Figures 44A and 44B are modified flaw charts of an indicating operation of a hyper-program shown in Fig. 39A;
25 Figure 45 is a flow chart of a sub-routine of a second Tv dial checking operation; and, Figure 46 is a flow chart of a sub-routine of a second Av dial checking operation.
Figure 47 is a plan view of a single lens reflex camera having an exposure control apparatus according to the present invention;
Figure 48 is a block diagram of a control circuit of an exposure control apparatus shown in Fig. 47;
Figure 49 is a flow chart of a main operation of a to CPU of a control circuit shown in Fig. 48; and, Figures 50 and 51 are flow charts of a manual exposure control of a control circuit shown in Fig. 48.

~C~~~~~~~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention will be discussed below with reference to the preferred embodiments of the present invention.
Figures 1 and 3 are a plan view and a front elevational view of a single lens reflex camera body having an exposure control apparatus according to the present invention, respectively. Figure 2 is a back view of a DX
code reading portion of the camera body shown in Figs. 1 and 3.
io The camera body 11 has a grip portion 13 which is provided, on a front end (i.e., the object side) of an upper surface thereof, with a shutter button 15. A Tv electronic dial 17 and an Av electronic dial 19 are provided behind the shutter button 15 and on an upper end Ls of the back surface of the c_trip portion 13, respectively.
Both the Tv electronic dial 17 and the Av electronic dial 19 are in the form of rotary dials which will be discussed below in detail. When the Tv electronic dial 17 and the Av electronic dial 19 are rotated, the shutter speed Tv, the 2o diaphragm value Av and the exposure mode can be changed.
The Tv electronic dial 17 and the Av electronic dial 19 constitute part of first and second manual setting means or first and second shutter speed and diaphragm value manual setting means, respectively.
2s A clear button 23 is provided on the upper portion of the back surface of the camera body 11 in the vicinity of the Av electronic dial 19. A hold button 25 is provided on the right side of the clear button 23. The clear button 23 constitutes a part of a clear switch means.
The electronic dials 17 and 19, the clear button 23, and the hold button 25 are arranged so that when a photographer holds the camera body 11 in a normal posture, they can be actuated by his or her thumb or forefinger without having to shift the camera body 11.
~o A slidable exposure correction/ISO lever 27 and a slidable exposure mode/drive lever 29, both being slidable in opposite directions from a neutral position are located on the top surface of the camera body 11 to the left of a pentagonal prism. A main switch 31 is located on the top 5 surface of the camera body 11 to the right of the pentagonal prism and can be moved to three different positions in a slidable manner.
DX pins DX1 ~-DX6 are provided in a patrone receiving chamber 33 of the camera body 11 and come into contact with 20 DX codes, which are printed on the surface of a patrone of film, to thereby read the data. In particular, the DX pins DX1 -..DX6 are brought into contact with the portion of the DX codes which represents the ISO sensitivity Sv, so as to read the data thereof.
25 A group of mount pins (CONT, RES/Fmin3, SI/Fmin2, F'maxl, A/M, Fmax2, and SCTC /Fminl) are provided on a body mount 35 of the camera body 11 to effect, for example, data communication between the camera body 11 and a taking lens. When the body mount 35 is attached to a lens mount of the taking lens, the mount pins of the body mount 35 are electrically connected to the corresponding mount pins of the taking lens, so that the camera body 11 can read lens data, including a minimum F number Fmin (open F number) and a maximum F number, from the taking lens and perform data to communication with a control means (ROM or CPU). The control means (ROM or CPU) is provided in the taking lens to read additional lens data, such as focal length data f, or data representing the kind of taking lens attached, etc. Note that a mark or a symbol, etc., with an affix "-"
and a suffix "~" (e. g., -SCK , as mentioned above) represent an active low or an inverted value in this specification.
Figure 4 shows a circuit arrangement of a control unit of a camera system according to the present invention.
2o The camera body 11 has CPU 41 and TPU 43 as a control means. The CPU 41 performs the fundamental photographic calculations and control functions, such as the calculation and determination of the exposure factors (i.e., diaphragm value Av and shutter speed Tv), exposure control, calculation of data necessary for automatic focus control, etc. The CPU 41 also functions as a means for compulsively changing the mode, returning an exposure mode, changing a priority exposure factor, compulsively changing an exposure mode within a specific exposure mode, setting a limit value, holding an exposure value, manual shifting, and switching a set mode.
The IPU 43 functions as an input interface of the switches, such as the shutter button 15, the Tv electronic dial 17, the Av electronic dial 19, etc. The IPU 43 also l0 functions as an exposure mode setting means, a means for controlling the indicators, a regulator for making the power source of the CPU 41 ON and OFF (power holding), and memory means for storing the set data and shutter speed Tv, etc. The IPU 43 has a ROM 43a which stores programs for i5 determining the input of the switch data, indication of the modes, conununication with the CPLJ 41, communication with the taking lens, etc. The IPU 43 also has a RAM 43b which temporarily stores the set modes, the shutter speed Tv, and the diaphragm value, etc. The IPU 43 further has an EZPROM
20 (EZPROM) 43c which holds the number of film, the ISO
sensitivity, etc., even after the camera power source is turned OFF.
The IPU 43 communicates with the taking lens 65 and receives lens data, such as a maximum F number Fmax, the 25 minimum F number Fmin and the focal length f, etc. The IPU

~~~~~~~w 43 communicates with the CPU 41 to transmit and receive the data therebetween to control the photographic operation and the indication of the data.
The output of a light receiving element 45 is logarithmically compressed by an operation amplifier 47 and a diode D1, amplified by an amplifier 49, converted to a digital value (Bv, BV) corresponding to an apex value by an A/D converter 51, and input to the CPU 41 through input ports P30 ~- P37.
1o The A/D converter 51 operates at a predetermined time to input the level signals of the ports P30 ~ P37 to the CPU 41 which reads object brightness signals and diaphragm value signals set by the taking lens 65 and converts the signals to corresponding apex values. The port P40 is an input switching control port which switches the logarithmically compressed voltages amplified by the amplifier 49 and the diaphragm voltages set by the diaphragm volume 53. The diaphragm volume 53 generates diaphragm voltage which corresponds to the value set by the ?o photographer when rotating the diaphragm ring of a taking lens (not shown) in the manual made.
The ports P10 -~-P14 of the CPU 41 are connected to the DX pins DX2 ~- DX6. The CPU 41 checks the levels of these ports P10 -~-P14 at a predetermined time to read the ?5 ISO sensitivity Sv. The CPU 41 then stores the input data including the diaphragm value Av, the object brightness Bv and the ISO sensitivity Sv, etc., in the RA~I 41b at predetermined addresses.
A winding motor 55 winds and rewinds the film, and a mirror motor 57 moves a mirror up and down. The operations of the motors 55 and 57 are controlled by the CPU 41 through a motor drive circuit 59.
A release magnet RL releases the mechanical engagement of the shutter to begin the release operation. A
shutter mechanism (shutter curtain) thus released from the mechanical engagement by the release magnet RL is disengageably engaged by a leading curtain magnet ES1 and a trailing curtain magnet ES2, so that the movement of the shutter curtain is controlled thereby. A diaphragm magnet EE stops the stop-down operation of the the taking lens diaphragm. The operations of theae magnets are controlled by the CPU 41 through a magnet drive circuit 61.
An EE pulse counter 63 generates EE pulses in association with the stop-down operation, which is in turn 2o associated with the up--down movement of the mirror, subsequent to the shutter release and sends the outputs thereof to the port PDD of the CPU 41. The CPU 41 counts the level change of the port PDD and when the counted number reaches a value corresponding to the set diaphragm value Av, the diaphragm magnet EE is turned OIL through the magnet drive circuit 61 to stop the stop-down operation thereby maintaining the diaphragm value Av.
The ports PLO-PL6 of the CPU 43 are connected to the mount pins (A/M, CONT, RES/Fmin3, SI/Fmin2, Fmaxl, Fmax2, -SCK /Fminl) thereby completing an electrical connection to the taking lens 65 (i.e., memory or control means thereof). The IPU 43 communicates with the taking lens 65 through the ports PLO ~r PL6 to read the lens data including the open F number Fmin, the maximum F number Fmax, the i0 focal length f, etc.
The taking lens 65 has a lens auto/manual selection switch 67 which sw itches between a manual diaphragm mode (lens-manual mode) and an automatic diaphragm mode (lens-auto mode) in association with a diaphragm ring 12.
The lens auto/manual selection switch 67 is connected to an input port PLO of the IPU 43 through the mount pin A/M. The IPU 43 determines the existence of the manual diaphragm mode or the automatic diaphragm mode in accordance with the level of the port PLO. The "lens-auto mode" mentioned above 2o is an automatic diaphragm mode in which the stop-down mechanism of the camera continues the stop-dawn operation until the diaphragm value becomes a predetermined value which has been set in the camera body. The "lens manual mode" mentioned above is a manual diaphragm mode in which the diaphragm value is manually set on the taking lens v side. The lens-auto mode will also be referred to as a "body set" hereinafter.
Input ports PCO ~- PC2 and PBO -~- PB5 of the IPU 43 are connected to a main switch SWMAIN, a photometer switch SWS, a release switch SWR, an exposure mode switch SWMODE, a drive switch SWDRIVE, an exposure correcting switch SW~ EF, an ISO sensitivity setting switch SWISO, a clear switch SWCL and a hold switch SWHOLD, respectively.
The main switch SWMAIN is associated with a main to switch lever 31. The photometer switch SWS and the release switch SWR are associated with the shutter button 15. The switch SWS remains open until the shutter button 15 is depressed by a half step at which point it is turned ON.
The switch SWR is turned ON when the shutter button 15 is depressed by full step. The exposure mode switch SWMODE and the drive switch SWDRIVE are associated with the exposure mode/drive lever 29. The exposure correcting switch SW~ EF
and the ISO sensitivity setting switch SWISO are associated with the exposure/ISO lever 27. The clear switch SWCL and 2o the hold switch SWHOLD remain open until their respective associated buttons, clear button 23 and hold button 25, are effected.
The IPU 43 detects the ON/OFF state o.f 'the switches SW, mentioned above, in accordance with the input levels of the input ports PC and FB of the IPU 43 to perform the necessary operations.
A pair of input ports PAO and PA1 and another pair of input ports PA2 and PA3 of the IPU 43 are connected to the TV electronic dial 17 and the Av electronic dial 19, respectively. Each of the TV electronic dial 17 and the Av electronic dial 19 has a click-stop rotation mechanism per se known. For example, a pair of input ports PAO and PA1 are in a floating state at a click-stop position, when the electronic dials 17 and 19 are rotated in a clockwise or i0 counterclockwise direction, the level of one of the input ports first drops to "L" and then the level of the other drops to level "L", in accordance with the direction of the rotation of the dials. Thereafter, the one input port, the level of which has dropped to level "L" prior to the other, is returned to the floating state prior to the other. Since the order of change in the level of the input ports PAO and PAZ or PA2 and PA3 depends an the rotation of the dials, the IPU 43 can discriminate the direction of rotation based on the order of change.
A c3roup of ports PLCD of. the IPU 43 are connected to an LCD display panel 69 and an indicator 71. The indicator 71 is located in the finder. The LCD panel 69 is controlled by the IPU 43 to indicate various photographic information, such as the exposure mode, the shutter speed Tv, the diaphragm value Av, the number of remaining frames in a roll of film, the drive mode and other data (i.e., ISO
sensitivity data, and exposure correcting data~ EF, etc.).
The indicator 71 within the finder has indicating elements 71a and 71b which indicate the shutter speed Tv, the diaphragm value Av, and an under-exposure, over-exposure or optimum exposure of the film. The indicator 7I also has an indicating element 71c which indicates whether or not the memory is locked.
The main circuit structure of the camera system z0 according to the present invention, as discussed above, operates as follows. Note that the values of the shutter speed Tv, the diaphragm value Av, and the object brightness Bv in the arithmetic operation discussed below are all those used in calculating the APES values.
a5 ~~~~a~~'~;
Main Operation of CPU
The main operation of the CPU 41 will be discussed below with reference to the flow chart shown in Fig. 5. The main operation is carried out in accordance with the program stored in the ROM 41a of the CPU 41.
When the photometer switch SWS is turned ON after the main switch SWMAIN is turned ON, electrical power is supplied to the CPU 41 and the operation shown in the flow chart of Fig. 5 is performed.
io The CPU 41 first initializes all the input ports P at step 511, and then initializes the RAM 41b at step 512.
Thereafter, the DX code (ISO sensitivity SV), the object brightness Bv, and the diaphragm value Av set by the diaphragm volume 53 when in the L~M mode, are input to the CPU (steps 513, S14 and S15).
Thereafter, the CPU 41 communicates with the IPU 43 to receive the necessary data, such as the set photographic exposure mode and the exposure factors, etc., from the IPU
43 (step S16).
2U The control proceeds to step S18 in which the exposure calculation is effected to obtain optimum exposure factors in accordance with the selected photographic exposure mode, the calculation being based on the ISO
sensitivity Sv and the object brightness Bv, etc.
Thereafter, the CPU 41 performs data communication with the IPU 43 to send the calculated exposure factors (i.e., shutter speed Tv and diaphragm value Av) to the IPU 43 (step S19).
After the exposure factors are determined, the control proceeds to step S20 where it is determined whether or not the release switch SWR is turned ON. If the release switch SWR is turned ON, the releasing operation is effected (step S21). If the release switch SWR is turned OFF, the control is returned to step S13. While the power to is held (i.e., while the power continues to be supplied), the operations of step S13 to step S20 are repeated.
Data Communication with IPU
The CPU 41 performs data communication with the IPU
~5 43. The data communication will be explained below with reference to Fig. 6 and Table 1 (attached to the last page of the specification). Each of tree CPU 41 and IPU 43 has terminals corresponding to CE, READY, SCK , and DATA which are connected to each other.
zo The CPU 41 raises the level of the terminal CE (not shown) , so that IPU 43 is ready for communication. When the IPU 43 monitors the level of the terminal CE which is changed from "L" to "H", the level of the terminal READY is dropped and then raised, so that interruption by the CPU 41 25 is permitted.

When the CPU 41 monitors the permission to interrupt, a clock signal is output to the terminal -SCK (not shown), and a command is output to the terminal DATA. Upon completion of receipt of the command, the IPU 43 drops and then raises the level of the terminal READY, so that the CPU 41 detects the completion of the receipt. The IPU 43 outputs data corresponding to the received command in accordance with the clock signal sent from the terminal SCK of the CPU 41, or receives data from the CPU 41.
When the communication of the necessary data is completed, the IPU 43 drops the level of the terminal READY. Thereafter, the CPU 41 drops the level of the terminal CE, so that the IPU 43 detects that the data communication with the CPU is completed. When the IPU 43 monitors the level drop of the terminal CE, the IPU 43 raises the level of the terminal READY to finish the data communication.
AE Sub-routine 2o The sub-routine for calculating the exposure (automatic exposure mode) at step S18 will be discussed below with reference to the flow chart shown in Fig. 7.
In this AE process, the DX codes representing the ISO
sensitivity are converted to APEX values (film sensitivity Sv) at step S50. The DX codes of the ISO sensitivity consist of 5 bit signals and are read by the five DX pins (5 bits) DX4, DX3, DX2, DX5 and DX6 which come into contact with the codes in the illustrated embodiment. The upper three bits (DX4, DX3 and DX2) constitute an integer arid the lower two bits (DX5 and DX6) a decimal. For example, if the decimal is "O1" or "11", the APEX value is 0/3, if the decimal is "10", the APEX value is 1/3, and if the decimal is "00", the APEX value is 2/3. The decimal thus converted to the APEX value is added to the integer. For example, the io DX code of ISO 100 is represented by Sv=5, since the integer "101" is converted to an APEX value "5°' and the decimal "O1" is converted to an APEX value "0".
Thereafter, the object brightness Bv is converted to a calculating object brightnea s BVD suitable for i5 calculation by using the following equation: BVD=Bv -I- 7, (step S51). Thereafter, the film sensitivity Sv and the exposure correcting value Xv are converted to a calculating sensitivity SVD and a calculating exposure correcting value XVD suitable for calculation by using the following z0 equations, respectively (step S52):
SVD=Sv- 1; XVD=4- Xv The above-mentioned operations are effected not only to prevent the values of the calculating exposure factors BVD, SVD, XVD from being negative, but also to unify the 25 accuracy or precision of the exposure factors to be a 1/8Ev step. Consequently, the APEX calculation (i.e., addition and subtraction) can be easily effected without considering the calculation accuracy. Note that since the precision of Sv and Xv is within 1/3 Ev, it is in theory impossible to convert them to values of a 1/8Ev step. To this end, Sv and Xv are rounded to approximately 1/3Ev and 2/3Ev to 3/8Ev and 5/BEv, respectively.
Thereafter, the brightness correction value MND
depending on a change of the open F number, is calculated io at step 553. The brightness correction value MND is adapted to correct the object brightness Bv so as to maintain the exposure on a film plane at a constant value, regardless of, for example, a change in the open F number (i.e., change in brightness of the lens) during zooming and is a i5 value peculiar to the taking lens. The brightness correction value MND is input from the taking lens by communication of the IPU 43 with the taking lens (IPU-lens communication), which will be discussed hereinafter, and is transferred from the IPU 43 to the CPU 41 through the 2o CPU-IPU communication at step S16.
Thereafter, the calculating exposure value LVD is calculated, based on the calculating object brightness BVD, the calculating sensitivity SVD, the calculating exposure correcting value XVD, and the brightness correcting value 25 MND by using the following formula;

LVD=BVD -f- SVD + XVD + HIND
The CPU 41 detects the selected exposure mode and calls the exposure factor calculating sub-routine corresponding to the selected exposure mode (steps 555-1-555-n, 556-1-~-556-n). The diaphragm value Av and the shutter speed Tv are then calculated in accordance with the algorithm of the selected exposure mode. Thereafter, the control is returned. If an incorrect exposure mode is set, an error operation as described below is carried out (step to 557).
Error Operation In the error operation at step 557, the calculating shutter speed TVD and the calculating diaphragm value AVD
are replaced with a calculating maximum shutter speed TVDMAX and a calculating maximum diaphragm value AVDMAX, respectively, and the number PN (or Pno) of EE pulses is set at the maximum value, i.e., 225. Thereafter, the calculating shutter speed TVD (the calculating maximum 2o shutter speed TVDMAX ) and the calculating diaphragm value AVD (i.e., the calculating maximum diaphragm value AVDMAX) are converted to values suitable for transmission to the IPU in processes labeled TVDT (TVD-~TVT) and AVDT (AVD-AVT), as explained in detail hereinafter (see Fig. 8).
Thereafter, the control is returned.

It is possible to replace one or both of the calculating shutter speed TVD and the calculating diaphragm value AVD with a calculating minimum shutter speed TVDMIN
and a calculating minimum diaphragm value AVDMIN, in place of the calculating maximum shutter speed TVDMAX and the calculating maximum diaphragm value AVDMAX, respectively.
Exposure Calculating Sub-routine In the illustrated embodiment, the exposure modes io include a program automatic exposure mode in which the shutter speed and the diaphragm value are automatically set in accordance with the object brightness, a shutter speed priority (EE LA) automatic exposure mode (lens-auto mode) in which the diaphragm value :is automatically set in accordance with the manually set shutter speed and object brightness, a diaphragm priority (ES LA) automatic exposure mode in which the shutter speed is automatically set in accordance with the manually set diaphragm value and object brightness, a manual exposure (Manual LA) and bulb exposure (Bulb LA) modes, and a diaphragm priority (ES LA) automatic exposure mode (lens-manual mode).
Furthermore, in the illustrated embodiment, there is a limited program (Program LIMT) automatic exposure mode, a hyper-program (Hyper Program) automatic exposure mode used as a specific program exposure mode, a hyper shutter ~~~'~~c~.~~
priority (Hyper EE) automatic exposure mode (lens-auto mode), and a hyper diaphragm priority (Hyper ES) automatic exposure mode.
The following discussion will be directed to an exposure factor calculation process in the above-mentioned exposure modes with reference to Figs. 9 through 23.
Hyper Program The hyper program exposure mode referred to herein is i0 a mode in which the program mode, the EE automatic exposure mode and the ES automatic exposure mode are changed by optionally selecting the hyper program exposure mode, the hyper EE automatic exposure mode, or the hyper ES automatic exposure mode. Operations of Hyper-program mode are identical to those of the ordin<~ry program mode, except that the exposure mode can be varied between the above three modes by actuating the electronic dials 17,19 or the clear button 23.
Figure 9 shows a flow chart involving the hyper program exposure mode and the ordinary program exposure mode and Fig. 10 shows a program diagram thereof.
First, the relationship between the calculating TVD
corresponding to the Tv value and the calculating AVD
corresponding to the Av value is obtained by the following formula, in accordance with the formula at step S54.

d3' LVD=BVD+ SVD + XVD -+- MND
=(Bv+ 7)+ (Sv - 1)+ (4- Xv) + MND
_ ( Bv+ Sv- Xv+ MND ) + 10 =Ev + 10 =Tv + Av+ 10 =(Tv+ 5 4/8)+ (Av + 4 4/8) =TVD+ AVD
Here, Ev=Bv + Sv- Xv+ MND
TVD=Tv + 5 4/8 ...(1) AVD=Av + 4 4/8 ...(2) From the equations (1) and (2), the relationships between Tv and TVD and between Av and AVD are obtained. The 'respective constants added to Tv and Av in equations (1) i5 and (2) are not limited to 5 ~/8 and 4 4/8 and can be any two values whose sum is 10. The values of 5 4/8 and 4 4/8 are selected to be approximate to each other in the embodiment. Correspondences between Tv and TVD and between Av and AVD thus obtained are shown in Table 2 and Table 3 2o (attached to the last page of the specification), by way of example:
In the program exposure mode, the optimum calculating shutter speed TVD is obtained by the following equation:
TVD=3/8 LVD + 4 6/8 25 The calculating exposure value LVD is obtained at step 554. Consequently, the optimum calculating diaphragm value AVD is obtained from the result of this calculation ( steps 561-. S78 ) .
The equation mentioned above is obtained from the basic formula of_ the program line (Tv=3/8 Ev+ 3) in which TVD=Tv+ 5 4/8 and AVD=Av+ 4 4/8. When the optimum calculating shutter speed TVD and the optimum calculating diaphragm value are within the shutter capability range of the camera body 11 (range between the calculating maximum to shutter speed TVDMAX and the calculating minimum shutter speed TVDMIN) and the diaphragm capability range of the taking lens (range between the calculating maximum diaphragm value AVDMAX and the calculating minimum diaphragm value AVDMIN), the optimum calculating shutter speed and the optimum calculating diaphragm value are maintained, and the EE pulse numkaer PN, used to maintain the diaphragm value Av of the diaphragm of the taking lens during the releasing operation, is calculated (steps 562, S64 -.566, 568, 569, S72). The maximum shutter speed TVDMAX
and the minimum diaphragm value AVDMIN referred to are the maximum shutter speed and the open F number, respectively.
The maximum and minimum shutter speeds TVDMAX and TVDMIN are peculiar to the camera body 11 and are TVDMAX
=13 (1/8000 sec.) and TVDMIN -- 5 (30 sec.) in the illustrated embodiment, respectively. Consequently, as Gad a'~?
TVD='rV+ 5 4/8, the calculating maximum and minimum shutter speed TVDMAX and TVDMIN are represented respectively by;
TVDMAX =TVMAX + 5 4/$=18 4/8 TVDMIN =TVMIN + 5 4/8=0 4/8 The calculating maximum and minimum shutter speed TVDMAX and TVDMIN are stored in advance in the internal ROM
41a of the CPU 41 and are memorized at predetermined addresses of the RAM 41b during the operations.
Using the inherent maximum and minimum diaphragm 1o values AVMAX and AVMIN and the formula (AVD=AV+ 4 4/8), the calculating maximum and minimum diaphragm values AVDMAX and AVDMIN are represented respectively by;
AVDMAX =AVMAX + 4 4/8 AVDMIN =AVMIN -1- 4 4/8 The maximum and minimum diaphragm values AVMAX and AVMIN are input by the communication with the taking lens at step S35 and the calculating maximum and minimum diaphragm values AVDMAX and AVDMIN are stored in the internal RAM 41b of the CPU 41 at predetermined addresses 2o thereof.
If the object is too bright or dark to calculate the optimunt exposure factors using the above-mentioned program line, the following operations are carried out.
When the object is too bright:
z5 If the calculating shutter speed TVD is larger than the calculating maximum shutter speed TVDMAX, the optimum calculating diaphragm value AVD is calculated after the calculating shutter speed TVD is replaced with the calculating maximum shutter speed TVDMAX (steps S62 -~-S64).
If the optimurn calculating diaphragm value AVD thus obtained is within the diaphragm capability range, the EE
pulse number PN is obtained in accordance therewith (steps 565, 566, S68 and S72).
If the optimum calculating diaphragm value AVD is to larger than the calculating maximum diaphragm value AVDMAX, the optimum calculating shutter speed TVD is recalculated after the optimum calculating diaphragm value AVD is replaced with the calculating maximum diaphragm value AVDMAX (steps S65 -~ S68). If the recalculated calculating shutter speed TVD is larger than the calculating maximum shutter speed TVDMAX, it is out of the range in which optimum exposure can be obtained by any combination of the calculating shutter speed TVD and the calculating diaphragm value AVD. Consequently, an Ev out-of association 2o bit is set at "1" to indicate that the calculating shutter speed is out of association (i.e., the allowable range), and the calculating shutter speed TVD is then replaced with the calculating maximum shutter speed TVDMAX to calculate the EE pulse number PN (steps S69 ~- S72). If the recalculated calculating shutter speed TVD is within the shutter capability range, since optimum exposure can be effected, the control skips steps S70 and S71 and performs the calculation of the EE pulse number PN in accordance with the optimum calculating diaphragm value AVD (steps S69 and 72).
When the EV out-of association bit is set at "1", the shutter speed (maximum shutter speed TVMAX) and the diaphragm (maximum diaphragm value AVMAX) is indicated in the LCD display panel 69 in a flickering manner.
to When the object is too dark:
If the optimum calculating diaphragm value AVD is smaller than the calculating minimum diaphragm value AVDMIN, the optimum calculating shutter speed TVD is recalculated after the calculating diaphragm value AVD is i5 replaced with the calculating minimum diaphragm value AVDMIN. If the recalculated calculating shutter speed TVD
is within the shutter capability range, the value is held and the EE pulse number PN is set at 0, as the diaphragm is an open F number (steps S73-~-S75, S78).
zo If the optimum calculating shutter speed TVD is smaller than the calculating minimum shutter speed TVDMIN, under-exposure conditions exist, and accordingly, the Ev out-of association bit is set at "1" and the calculating shutter speed TVD is replaced with the calculating minimum 25 shutter speed TVDMIN. Thereafter, the EE pulse number PN

is set at 0 (steps S75-~ S78). TVD and AVD are stored at predetermined addresses of the RAM 41b and are utilized to control the shutter speed and diaphragm value when releasing.
When the above-mentioned operations are completed, the calculating diaphragm value AVD and the calculating shutter speed TVD are replaced with a transferring diaphragm value AVT and a transferring shutter speed TVfi, respectively (steps S79 and S80). The relationships between i0 the calculating diaphragm value AVD and the transferring diaphragm value AVT and between the calculating shutter speed TVD and the transferring shutter speed TVT are as follows.
TVT=TVD+ 10 4/8 AVT=AVD
Although TVT and AVT are not rounded in the above equations, TVT and AVT are rounded in the actual operation.
The transferring shutter speed TVT and the transferring diaphragm value AVT are data of a 1/2Ev step.
2o Namely, when this data is transferred from the CPU 41 to IPU 43, the calculated values of a 1/8Ev step are rounded to 1/2Ev. This is because the data is used only to indicate the necessary information in the IPU 43, so that accuracy greater than a 1/2Ev step is unnecessary. Tables 2 and 3 mentioned above show indicating sections corresponding to the values of TVD and AVD by way of example.
Thus, the operation of the program exposure mode is finished and the program line (diagram) shown as a solid line in Fig. ZO is obtained.

Limited Program Exposure Mode Figure 11 shows a sub-routine of the limited program exposure (automatic exposure) mode in which a photographer can set the calculating minimum and maximum shutter speeds TVD1 and TVD2 and the calculating minimum and maximum diaphragm values AVDl and AVD2, respectively. The operational flow in this sub-routine is similar to that of the sub-routine of the program exposure mode except for the following points. Namely, in the sub-.routine shown in Fig.
l0 11, the calculating minimum and maximum diaphragm values AVDMIN and AVDMAX are replaced with the set minimum and maximum diaphragm values AVD1 and AVD2, respectively (steps 585, 593, 586, S87), and the calculating minimum and maximum shutter speeds TVDMIN and TVDMAX are replaced with i5 the set minimum and maximum shutter speeds TVD1 and TVD2, respectively (steps 595, S97, S82,S83, 589, S91). The program diagram of the limited program exposure mode is shown in Fig. 12.
The calculating minimum and maximum diaphragm values 2o AVDMIN and AVDMAX, and the calculating minimum and maximum shutter speeds TVDMIN and TVDMAX are set by actuating the hold button 25 and rotating the Tv electronic dial 17 and the Av electronic dial 19 when the limited program exposure mode has been selected. The setting operation shown in the 25 flow chart of Figs. 39C and 39D will be discussed in detail hereinafter.
Hyper-EE Automatic Exposure Mode Figure 13 shows a flow chart of the hyper-shutter priority (Hyper-EE) automatic exposure mode. The program diagram thereof is shown as a dotted-dashed line in Fig. 10.
The operation for calculating the exposure factors at the hyper-shutter priority automatic exposure mode is basically the same as the operation of the ordinary shutter to priority automatic exposure mode (lens-auto mode), except that the exposure mode can be changed by actuating the electronic dials 17, 19 or the clear button 23.
The hyper-EE automatic exposure mode is an EE
automatic exposure mode which is compulsively selected when the hyper program exposure mode is selected and when the Tv electronic dial 17 has been actuated. Return from the hyper-EE automatic exposure mode to the hyper-program exposure mode is effected by the operation of the clear button 23 or the power switch, etc. The switch from the 2o hyper-EE automatic exposure mode to the hyper-ES exposure mode is compulsively effected by the rotation of the Av electronic dial 19.
In the hyper-EE automatic exposure mode, the set shutter speed TVT transferred from the IPU 43 by the data communication is read and converted to the calculating ~~~~v~~~
shutter speed TVD (step 5101). The relationship between the transferring shutter speed TVT and the calculating shutter speed TVD is as follows.
TVD=TVT- 10 4/8 The transferring shutter speed TVT, which is 1/2 Tv in step, is converted to the calculating shutter speed TVD, which is 1/8 Tv in step, by the above operation.
The transferring shutter speed TVT is .represented by data of a 1/2Ev step and is processed upon calculating, so to that the decimal place thereof is identical to that of the calculating shutter speed TVD (i.e., data which is 1/8Ev in step). Accordingly, the Tv value, which is set by the user (i.e., TVT) set as the calculating shutter speed TVD in predetermined addresses of RAM 41b.
Thereafter, the optimum calculating diaphragm value AVD is calculated using the calculating shutter speed TVD
and the calculating exposure value LVD (step 5102).
If the optimum calculating shutter speed AVD is within the diaphragm capability range, the values are held 2o and the EE pulse number is calculated (steps 5103, S104, 5108- 5110 ) .
If the optimum calculating diaphragm value AVD is out of the diaphragm capability range, namely, if the object is too bright or dark, the following operations are performed.
When the object is too bright:

If the optimum calculating diaphragm value AVD is greater than the calculating maximum diaphragm value AVDMAX, the calculating diaphragm value AVD is replaced with the calculating maximum diaphragm value AVDMAX. This replacement causes an over-exposure condition, and accordingly, the EE pulse number PN is set after the Av out-of-association bit signal is set at °'1" to indicate that the optimum calculating diaphragm value AVD is out of association (steps 5103, 5106 ~- 5110). When the Av to out-of-association bit signal is set, the number "22", indicating the diaphragm value Av in the LCD display panel 69, flickers to indicate over-exposure.
When object is too dark:
If the optimum calculating diaphragm value AVD is smaller than the calculating minimum diaphragm value AVDMIN, the calculating diaphragm value AVD is replaced with the calculating minimum diaphragm value AVDMIN. This replacement causes an under-exposure condition, and accordingly, the EE pulse number PN is set at "0" after the 2o Av out-of-association bit signal is set at "1" (steps 5103-~-5105, 5107, S108, and 5110). Thus, the diagram as shown as a dotted and dashed line in Fig. 10 is obtained.
When the setting of the EE pulse number PN is finished, the calculating diaphragm value AVD and the calculating shutter speed TVD are converted to the ~~~e~~b transferring diaphragm value AVT and the transferring shutter speed TVT to complete the operation, respectively (steps 5111 and 5112).
Hyper-ES Automatic Exposure Mode An embodiment of the hyper diaphragm priority (ES) automatic exposure mode (lens-auto mode) will be explained below with reference to Figs. 10 and 16.
The basic operations in the hyper-ES automatic io exposure mode is basically the same as the operation of the conventional ES automatic exposure mode (lens-auto or body-set mode).
The hyper-ES automatic exposure mode is an ES
automatic exposure mode which is compulsively selected when the hyper program exposure mode is selected and when the Av electronic dial 19 has been actuated. The return from the hyper-ES automatic exposure mode to the hyper-program exposure mode is effected by the operation of the clear button 23 or the power switch, etc. The switch from the hyper-ES automatic exposure mode to the hyper-EE exposure mode is compulsively effected by the rotation of the Tv electronic dial 19.
In the hyper-ES automatic exposure mode, the set diaphragm value AVT transferred from the IPU 43 by the data communication is read to convert same to the calculating ~~!y~~a diaphragm value AVD (step 5131). The transferring diaphragm value AVT is identical to the calculating diaphragm value AVD (i.e., AVD=AVT). Accordingly, the diaphragm value Av manually set by the user(i.e., AVT) is set as the calculating diaphragm value AVD at predetermined addresses of the FtAM 41b.
The transferring diaphragm value AVT is represented by data which is 1/2Ev in step, and it is processed upon calculating so that the place thereof is identical to that l0 of the calculating diaphragm value AVD (i.e., data which is 1/$Ev in step).
Thereafter, the optimum calculating shutter speed TVD
is calculated using the calculating exposure value AVD and the calculating exposure value LVD (step 5132).
If the optimum calculating shutter speed TVD is within the shutter capability range, the values are held and the EE pulse number is calculated in accordance with the calculating diaphragm value AVD (steps 5133, S134, S13$ ~-S14U).
If the optimum calculating shutter speed TVD is out of the shutter capability range, namely, if the object is too bright or dark, the following operations are performed.
When the object is too bright:
If the optimum calculating shutter speed TVD is greater than the calculating maximum shutter speed TVDMAR, 4 (7 ~'~~~'~a<
the calculating shutter speed TVD is replaced with the calculating maximum shutter speed TVDMAX. This replacement causes an over-exposure condition, and accordingly, the EE
pulse number PN is set after the Tv out-of-association bit signal is set at "1" to discriminate that the optimum calculating shutter speed TV is out of association (steps 5133, 5136-S140).
When the object is too dark:
If the optimum calculating shutter speed TVD is less than the calculating minimum shutter speed TVDMIN, the calculating shutter speed TVD is replaced with the calculating minimum shutter speed TVDMIN. This replacement causes an under-exposure condition, and accordingly, the EE
pulse number PN is set at "0" after the Tv out-of-association bit signal is set at "1" (steps 5133-5135, S137, 5138-5140).
When the EE pulse number PN is set, the calculating diaphragm value AVD and the calculating shutter speed TVD
are converted to the transferring diaphragm value AVT and 2o the transferring shutter speed TVT to complete the calculation of the exposure factors (steps 5141 and S142), respectively. Thus, the diagram as shown as a dotted line in Fig. 10 is obtained.
Second Hyper-EE or ES Automatic Exposure Mode D' The second hyper-EE or ES automatic exposure mode is an automatic exposure mode in which the priority exposure factor is modified only under the condition that the non-priority exposure factor cannot be adjusted to avoid s the occurrence of under-exposure or over-exposure. Namely, unlike the above mentioned hyper-EE or hyper-ES automatic exposure modes i.n which a change of the priority exposure factor (i.e., diaphragm value or shutter speed having a priority) does not take place even if the object is too to bright or dark, the exposure factor having a priority is modified when the modification of the exposure factor having no priority cannot be adjusted to avoid over-exposure or under-exposure.
In the second hyper-EE or ES automatic exposure mode, 15 if the shutter speed or the diaphragm value having priority causes under-exposure or over-exposure, the shutter speed or the diaphragm value is modified to provide an optimum exposure (Figs. 15 and 1B).
The operations in the second hyper-EE automatic 2o exposure mode and the second hyper-ES automatic exposure mode will be discussed below with reference to Figs. 14 and 17, respectively.
In the second hyper-EE automatic exposure mode, the set shutter speed TVT stored in the IPU 43 is read by the 25 operation of the Tv electronic dial 17 to convert same to ~~v~~~~~
the calculating shutter speed TVD, so that the optimum calculating diaphragm value AVD is calculated in accordance with the calculating shutter speed TVD and the calculating exposure value LVD (steps 5121 and 5122). If the optimum calculating diaphragm value AVD is within the diaphragm capability range, the control enters step 5132 of the hyper-ES automatic exposure mode as can be seen in Fig.
16 (steps 5123, 5125 and S127).
If the optimum calculating diaphragm value AVD is greater than the calculating maximum diaphragm value AVDMAX (i.e., if the object is too bright), the calculating diaphragm value AVD is replaced with the calculating maximum diaphragm value AVDMAX, and then the control enters step 5132. Conversely, if the optimum calculating diaphragm value AVD is less than the calculating minimum diaphragm value AVDMIN (i.e., if the object is too dark), the control enters step S132 after the calculating diaphragm value AVD is replaced with the calculating minimum diaphragm value AVDMIN (steps 5123, S125-~-5127).
In step 5132 of the hyper-ES automatic exposure mode (diaphragm priority automatic exposure mode), the calculating shutter speed TVD is recalculated to modify the shutter speed.
Consequently, the diagrams as shown by a solid line, a dotted line and a two-dotted and dashed line in Fig. 15 are obtained. As can be seen in Fig. 15, the optimum exposure range is widened. This can be considered a kind of program automatic exposure mode in which the shutter priority automatic exposure mode functions in a certain exposure range.
Tn the second hyper-ES automatic exposure mode, the set diaphragm value AV'P stored in the IPU 43 is read by the operation of the AV electronic dial 17 to convert the same to the calculating diaphragm value AVD, so that the optimum to calculating shutter speed TVD is calculated in accordance with the calculating diaphragm value AVD and the calculating exposure value LVD (steps 5151 and S152). If the optimum calculating shutter speed TVD is within the shutter capability range, the values are held and the control enters step 5102 of the hyper-EE automatic exposure mode in Fig. 13 (steps 5153, 5155 and 5157).
If the optimum calculating shutter speed TVD is greater than the calculating maximum shutter speed TVDMAX
(i.e., if the object is too bright), the calculating zo shutter speed TVD is replaced with the calculating maximum shutter speed TVDMAX, and then, the control enters step 5102 of the shutter priority automatic exposure mode.
Conversely, if the optimum calculating shutter speed TVD is less than the calculating minimum shutter speed TVDMIN (i.e., if the object is too dark), the control enters step S102 after the calculating shutter speed TVD
is replaced with the calculating minimum shutter speed TVDMIN. In step 5102, the calculating diaphragm value AVD
is recalculated to modify the diaphragm value (steps 5103 5112).
Consequently, the diagrams as shown by a solid line, a dotted line and a two-dotted and dashed line in Fig. 18 are obtained. As can be seen in Fig. 18, the optimum exposure range is extended. This can be considered a kind to of program automatic exposure mode in which the diaphragm priority automatic exposure mode functions in a certain exposure range.
Although the first and second hyper EE automatic exposure modes and the first and second hyper ES automatic i5 exposure modes are separately explained, the operations of these modes can be performed in the same camera. Namely, 2 ba.t signals of the exposure mode data of the EZPROM 43c included in the IPU 43 correspond to those of the above-mentioned first and second methods in the hyper-EE
20 and hyper-ES automatic exposure modes, respectively. The signal data is transferred to the CPU 41 by the CPU-IPU
communication, so that the 2 bit signals can be determined, after the hyper-EE mode or the hyper-ES mode is detected, to switch the first or second hyper-EE and hyper-ES modes.

LA Hyper-Manual Exposure Mode The hyper-manual exposure mode (body set mode) in which both the shutter speed and the diaphragm value can be manually set by the operation from the camera body side will be discussed below with reference to Fig. 19.
In the hyper-manual exposure mode (lens-auto or body set mode), a photographer can set the exposure factors by actuating the electronic dials 17 and 19. However, when the clear button 23 is turned ON, the optimum exposure factors io are automatically calculated in accordance with the object brightness Bv, based on the algorithm identical to that of the program exposure mode. When the clear button 23 is turned OFF, the calculated exposure factors are replaced with those which are manually set.
In the LA hyper-manual exposure mode, both the shutter speed Tv and the diaphragm value Av can be set when the Tv and Av electronic dials 17 and 19 are actuated, respectively. Furthermore, when the clear button 23 is turned ON, the function equivalent to the program automatic exposure mode can be performed. The set shutter speed Tv and diaphragm value Av are stored in the RAM 43b of the IPU
43 at predetermined addresses thereof and are indicated in the LC~7 panel 69 and the indicator unit 71 within the finder.
While the clear button 23 is turned ON, the calculating shutter speed TVD and the calculating diaphragm value AVD are calculated in accordance with the program exposure mode and the control then proceeds to step 5167 (step 5164).
Tf the clear button 23 is not turned ON, the set diaphragm value AVT and the set shutter speed TVT, transferred from the TPU 43, are converted to the calculating diaphragm value AVD and the calculating shutter speed TVD, and the control then proceeds to step 5167 io ( steps 5161 ~- S163 ) .
At step 5167, an exposure error p Ev is calculated by the following equation which is based on the optimum calculating exposure value LVD, obtained from the result of the actual photometering, and the exposure value (AVD +
i5 TVD), which is obtained by the calculating diaphragm value AVD, identical to the set calculating diaphragm value, and the calculating shutter speed TVD, identical to the set calculating shutter speed:
D Ev=LVD- ( AVD+ TVD ) 2o If the exposure error p Ev is within an allowable limit ( - 3/8 < p Ev< + 3/8), overexposure and underexposure indication bits are set to illuminate a pair of LED exposure indicating elements 71a and 71b (F°ig. 42E) in the indicator unit 71 within the finder (steps S168, 25 S170, 5171).

If the exposure error p Ev is greater than the allowable upper limit, only the overexposure indication bit is set to illuminate the indicating element 71a to thereby indicate over-exposure (steps S168 and 5169). Conversely, s if the exposure error p Ev is less than the allowable lower limit, only the underexposure indication bit is set to illuminate the indicating element 71b to thereby indicate under-exposure (steps 5168, 5170 and 5172). Although the allowable limit of exposure error p Ev is ~ 3/8Ev in to the illustrated embodiment, another limit may be selected.
Furthermore, the upper limit value and the lower limit value can be different from each other. It is also possible to read the latitude of the loaded film from the DX code, so that the allowable limit is determined to be identical 15 to that of the film latitude.
Thereafter, the number PN of EE pulses is obtained from the calculating diaphragm value AVD (steps S173, S174 and 5175), and the calculating diaphragm value AVD and the calculating shutter speed TVD are converted to the 20 transferring diaphragm value AVT and the transferring shutter speed TVT, respectively, When the clear button is turned OFF after being ON, the optimum exposure value in the program exposure mode is converted to the series value at steps 5162 and 5163, which 25 will be discussed hereinafter, and is stored at predetermined addresses of the RAM 41b with the accuracy equivalent to that of the manual mode.
As can be understood from the foregoing, since, when the clear button 23 is turned ON in the hyper-manual exposure mode, both the shutter speed Tv and the diaphragm value Av are modified to optimum values depending on the photometering data (object brightness Bv) in accordance with the program exposure mode, the optimum exposure value can be manually and quickly set by a simple operation.
Although the calculation of the optimum exposure factors continues whale the clear button 23 is turned ON in the above mentioned embodiment, it is possible to calculate the exposure factors and store the same in the RAM 41b only when the clear button 23 is switched from OFF to ON. In this alternative, at step 5161, whether the clear button 23 is switched from OFF to ON is checked.

~ 9 ~~'~'~~~~~:
Second LA Hyper-manual Exposure Mode In the above mentioned embodiment, the diaphragm value Av and the shutter speed Tv are modified to those detected by the photometering operation, in accordance with s the program automatic exposure mode, when the clear button 23 is turned ON. It is possible to modify only one of the exposure factors Av and Tv to an optimum value.
Furthermore, it is also possible to set the exposure factor or factors at the rounded or system Av and Tv values instead of the optimum exposure value Ev. The rounded (or system) values referred to herein mean values having steps (accuracies) which can be manually set and obtained by rounding calculated APEX values, taking into account the step of the APEX values calculated by the CPU 41 being smaller than that of 'the manually se:t APEX values.
Selection of the optimum value and the rounded value is determined in accordance with one bit of the hyper manual select flag of the EZPROM 43c. In the illustrated embodiment, as can be seen in Fig. 25, when the 0-order 2o bits are "0" and "1", the optimum value and the rounded value are selected, respectively. Furthermore, the kind of automatic exposure mode is determined in accordance with the first and second bits of the flag. The bit data can be preset when the camera is shipped or can optianally be set 2s and modified by a photographer.

F'ig. 24 shows a flow chart of an example in which at least one of the exposure factors is modified to an optimum value and an example in which the optimum/system value selection is effected in combination, using the data of the hyper manual select flag of the EZPROM 43c within the IPU
43. The data of the Ez PROM 43c is stored in the RAM 43b of the IPU 43 upon operation, and the same data is transferred to the CPU 41 also to be stored in the RAM 41b thereof by the CPU-CIP communication.
io The state of the clear button 23 is checked at step 5601. If the clear button 23 is turned ON, the control proceeds to step 5603 at which point the modifying mode of Tv and Av in the LA hyper-manual mode, in accordance with the hyper-manual select flag data, is checked. In the illustrated embodiment, the first and second bits of the hyper-manual select flag data are used. If the value represented by the 2 bits is "0", "1" and "2", the control proceeds to step 5605 (program automatic exposure mode operation), step 5607 (LA diaphragm priority automatic 2o exposure mode operation), and step 5609 (LA shutter priority automatic exposure mode operation), respectively.
If the value represented by the 2 bits is "3", the control proceeds to step 5611 without performing the exposure mode operation. Consequently, the calculating shutter speed TVD, the calculating diaphragm value AVD, the indicating shutter speed TVT, and the indicating diaphragm value AVT are memorized in the RAM 41b of the CPLJ ~1.
Thereafter, the system/optimum bits of the select flag data are checked at step 5611. If the value represented by the bits is "0", the control proceeds to step 5163 (system value setting operation) and if the value is "1", the control proceeds directly to the sub-routine of the Manual-1 (optimum value setting operation).
The optimum value setting operation is the same as to that of the first embodiment. The system value setting operation will be explained below. The calculation of AVTD
and TVTD subsequent to the operations at steps 5605, 5607 and 5609 means that the calculating shutter speed TVD
(5613) and the calculating diaphragm value AVD (5615) are i5 calculated again after the calculating optimum values AVD
and TVD are obtained, based on the indicating optimum values TVT and AVT which are obtained in accordance with the obtained calculating optimum values AVD (=AVT) and TVD
(TVT) (by the last calculation of AVDT and TVDT in the 2o sub-routine of steps 5605, 5607 and 5609). As a result, the calculating optimum diaphragm values AVD and the calculating optimum shutter speed TVD once obtained are replaced with the calculating system diaphragm value and the calculating system shutter speed, respectively. The 25 operations subsequent to step 167 are identical to those in ~~~'°u'~~t~.9~
the first embodiment.
In the second embodiment mentioned above, six kinds of LA hyper-manual exposure modes (control modes) below can be selected.
01 Exposure control by the optimum shutter speed Tv and the optimum diaphragm value Av which are obtained when the clear button 23 is actuated in the program automatic exposure mode (first embodiment);
~2 Exposure control by the system (rounded) shutter io speed Tv and the system (rounded) diaphragm value Av which are obtained when the clear button 23 is actuated in the program automatic exposure mode;
Exposure control by the optimum diaphragm value Av which is obtained when the clear button 23 is actuated in i5 the shutter speed priority automatic: exposure mode;
Exposure control by the system (rounded) diaphragm value Av which is obtained when the clear button 23 is actuated in the shutter speed priority automatic exposure mode;
20 ~5 Exposure control by the optimum shutter speed Tv which is obtained when the clear button 23 is actuated in the diaphragm priority automatic exposure mode;
~ Exposure control by the system (rounded) shwt.ter speed Tv which is obtained when the clear button 23 is 25 actuated in the diaphragm priority automatic exposure mode.

LM Hyper-Manual Exposure Mode The following discussion will be directed to the hyper-manual exposure mode (lens-manual mode) in which the shutter speed is set on the camera body side and the s diaphragm value is set by the taking lens 65, with reference to Fig. 17.
In the LM hyper-manual exposure mode, the shutter speed Tv is manually set by adjusting the Tv electronic dial 17, but when the clear button 23 (clear switch SWCL) l0 is turned ON, the shutter speed is automatically modified to an optimum value in accordance with the object brightness Bv.
If the clear button 23 is not turned ON, the transferring shutter speed TVT (value of 1/2EV step) sent a5 from the IPU 43 is directly converted to the calculating shutter speed TVT (steps 5181 and 57.82). Thereafter, the control proceeds to step 5185.
Conversely, if the clear button 23 is turned ON, the shutter speed Tv is calculated in accordance with the 20 lens-manual diaphragm priority (ES) automatic exposure mode which will be discussed hereinafter, based on the diaphragm value which is set by the diaphragm ring of the taking lens 65 and which is input through the diaphragm volume 53 and the A/D converter 5I by step SI5 in fig. 5 (steps 5181 and 25 5183). Thereafter, the selection of the system/optimum ~~~~b~~'~
values is effected similar to the LA hyper-manual exposure mode at step 5184. If the system value is selected, the calculation of TVDT is effected for the same reason as that in the LA hyper-manual exposure mode.
At step 5185, the calculating diaphragm value AVVRD
is calculated, based on the diaphragm value Av converted to the digital value AvA/D and set by the diaphragm ring of 'the taking lens 65 and based on the adjusting value AVadj peculiar to 'the camera body 11. Consequently, the exposure to error p Ev is obtained by the following equation (step 5186):
p Ev=L,VD- TVD - AVVRD - MND
If the exposure error p Ev is within the allowable limit, the overexposure and underexposure indication bits z5 are set. If the exposure error p Ev is greater than the upper limit value, the overexposure indication bit data is set, and if the exposure error p Ev is less than the lower limit value, the underexposure indication bit data is set (steps 5187 ~- S191). Thereafter, the EE pulse number PN is 2o set to the greatest value (255 in the illustrated embodiment), and the calculating shutter speed TVD is converted to the transferring shutter speed TVT. This completes the exposure factor setting operation (steps 5192 and 5193). The reason that the EE pulse number PN is set to 25 the greatest value is to ensure that the stop-down ~~'~~~~~~~
mechanism of the camera body 11 is driven to an extreme stop-down position corresponding to the diaphragm value set by the diaphragm ring of the taking lens 65.
As can be seen from the foregoing, according to the present invention, since the shutter speed Tv is set to the optimum value or the rounded system value obtained in the diaphragm priority automatic exposure mode when the clear button 23 is turned ON in the LM hyper-manual exposure mode, the optimum exposure value can be manually and quickly obtained by a simple operation.
LM Diaphragm Priority Automatic Exposure Mode The following discussion will be addressed to the lens-manual diaphragm priority (ES) exposure mode in which the diaphragm is set by the diaphragm ring of the taking lens 65, with reference to Fig. 21.
The calculating diaphragm value AVVRD is calculated in accordance with the converted diaphragm value AvA/D
which is obtained by converting the diaphragm value Av set 2o by the diaphragm ring of the taking lens 35, and the inherent adjusting value AVADJ of the camera body 11 (step 5201). Based on the AVVRD value thus obtained, the calculating shutter speed TVD is calculated by the following equation (step 5202);
TVD=LVD - AVVRD - MND

Thereafter, if the calculating shutter speed TVD is within the shutter capability range, the EE pulse number PN
is set to be the largest value (steps 5203, 5205, 5208). If the calculating shutter speed TVD is greater than the s calculating maximum shutter speed TVMAX, or less than the calculating minimum shutter speed TVMIN, the calculating shutter speed TVD is replaced with the calculating maximum shutter speed TVMAX (steps S203 and 5204), or with the calculating minimum shutter speed TVMIN (steps 5203, S205 io and 5206). Thereafter, the EE pulse number PN is set at the largest value after the Ev out-of-association bit is set (steps 5207, S208).
Finally, the calculating shutter speed TVD is converted to the transferring shutter speed to be 15 transferred to the IPU 43 to thereby complete the operation (step 5209).
LA, LM Bulb Exposure Mode The bulb exposure mode will be discussed below with 2o reference to Fags. 22 and 23.
In the lens-auto bulb exposure made, the transferring diaphragm value AVT set by the Av electronic dial 19 is read through the CPU-IPU communication and converted to the calculating diaphragm value AVD (step 25 S211). Thereafter, the EE pulse number PN corresponding to the calculating diaphragm value AVD is calculated (steps 5212 and 5213), the underexposure and overexposure indication bits are reset, and then, the calculating diaphragm value AVD is again converted to the transferring diaphragm value AVT (steps 5215 and 5215). The operation is thus completed. If the calculating diaphragm value AVD is identical to the calculating minimum diaphragm value AVDMIN, the EE pulse number PN is set at "0" (steps 5212, 5214).
to In the lens-manual bulb exposure mode, the EE pulse number PN is set at the greatest value, so that the stop-down mechanism can be driven to the diaphragm value set by the diaphragm ring of the taking lens. Thereafter, the underexposure and overexposure indication bits are reset to finish the operation.
IPU Main Routine The above explanation has been directed to the operations of the CPU 41. The main routine of the IPU 43 will be explained below (Fig. 26). The photographic data, such as the manually set diaphragm value Av and shutter speed Tv, the indicating diaphragm value Av and shutter speed Tv, the selected exposure modes, the transferring diaphragm value AVT and shutter speed TVT transferred through the communication between the CPU 41 and the taking lens, the maximum F number FNo, and the minimum F number FNo are stored in the internal RAM 43b of the IPU 43 at different addresses thereof.
The IPU 43 always operates when the battery is in the camera performing IPU-MAIN shown in Fig. 26. The IPU 43 first initializes the ports thereof and the RAM 43b to carry out the initial setting of the modes (steps 5220-~-5222). Thereafter, the exposure mode is set to its initial mode. The initial mode is determined in accordance with the state of the port PLO of the IPU 43 and is either the hyper program exposure mode or the diaphragm priority automatic exposure mode corresponding to the case of the lens-auto mode and the lens-manual mode, respectively.
Thereafter, intermittent operations are repeated by the 32ms timer (steps 5223-~-5229-2). The IPU 43 performs the following intermittent operations. When the set time of the 32ms timer is up, the switch inputs, i.e., the levels of the switch input ports PCO~- PB5 are successively input to the IpU 43. If the level. of the ports is "L" {ON), 2o the input operation corresponding to the switches and the .
determination of the type of taking lens are performed, so that the data, such as the modes set by the switches or the lens type data, etc., is written into the RAM 43b, and the lezis data is input to the IPU 43 through the communication with the lens (steps 5223 -~-S225). If time of the 32ms timer is not up, the control jumps to step 5228 (steps 5223 and S2.28 ) .
Thereafter, whether or not the main switch SWMAIN is turned ON is checked. If the main switch is turned OFF, the s Hyp-Tv flag and the Hyp-Av flag are reset to turn the power-hold OFF (i.e., turn the main power source of the CPU
41 OFF). Thereafter, the ML mode flag is reset (i.e., hold bit is cleared), and the control is then returned to step 5223 (steps S226, 5226-2, 5229-2). If the main switch to SWMAIN is turned ON, whether or not the photometering switch SWS is turned ON is checked. If the photometering switch SWS is turned ON, which usually means the picture takiIlg operation has already begun, the photometering timer starts and the power-hold is activated to actuate the CPU
s 41 (steps 5226, 5227-1, 5227-2 and 5228). Thereafter, control proceeds to step 5228. Conversely, i.f the photometering switch. SWS is not turned ON, control skips the start of the photometering timer and the power-hold operation to step 5228 (steps 5226, 5227-1 and 5228).
2o In step 5228, the diaphragm value (F) and the shutter speed (S-1) etc., used in the photographing operation at the selected photographic mode are indicated in the LCD
panel 69 and the indicator unit 71 within the finder.
Thereafter, whether or not the set time of the 25 photometering timer is up is checked. If the time is up, ~~'~~~~~'~
the power-hold is inactivated and the control is then returned to step 5223. Conversely, if the time is not up, the control is directly returned to step S223 (steps S229-1, 5229-2, 5223).
If the intermittent operation by the timer is interrupted by the communication with the CPU41, the communication is performed. Similarly, if the electronic dials 17 and 19 are rotated, the electronic dial setting is carried out. Note that when the main switch SWMAIN is to turned OFF, interruption does not occur.
Communication with Lens The sub-routine of the communication with the lens CPU at step 5225 will be described below with reference to Fig. 27. The CPU 43 drops the leveal of the pin CONT to "L"
(Logic "0"), and receives the mount pin data (open F number Fmin, the maximum F number Fmax, and Auto/Manual (A/M) data input thereta (steps S31 and S32). As disclosed in Japanese Patent Kokai (Unexamined Publication) No. 63-184719 filed 2o in the name o.f the assignee of the present application, the pins of the taking lens coming into contact with the pins RES/Fmin3, SI/Fmin2, Fmaxl, Fmax2 and SCK /Fminl are connected to the transistors, so that the maximum F number Fmax of 2 bits and the open F number Fmin of 3 bits are constituted by the levels thereof in combination depending on the ON/OFF states of the transistors. The pin A/M is connected to the A/M selection switch SWAM, so that the diaphragm Auto/Manual data of 2 bits is constituted by the ON/OFF states of the A/M selection switch.
The CpU 41 inverts the level of the pin CONT into logic "1" (i.e., level "H") to determine the presence of the automatic focusing (AF) lens KAF attached to 'the camera body and the kind of the attached lens (steps S33 and S34).
The taking lens which can be discriminated in the present l0 invention is a manual lens K having no mount pin, an auto lens KA having the mount pins but no lens ROM, or an auto AF lens KAF having the mount pins and the lens ROM.
If the level of the pin CONT is "1", the communication with the taking lens 65 is carried out and i5 the lens data is input (steps S34 and S35). If the levels of the mount pins Fmaxl, Fmax2., Fminl, Fmin2 and Fmin3 are alI "1", and if the 5 bits representing the kind of lens are "11111", it is determined that there is a problem with the lens, and accordingly, the no lens bit NoLens is set zo and the control is returned (steps 536, 537 and S38). If the level of at least one of the mount pins Fmaxl -~-Fmax2 and Fminl -r Fmin3 is "0" and if the kind of lens discriminated is the AF lens KAF, the AF lens KAFLens bit is set and the control is returned (steps 536, S39 and 25 S40 ) .

Otherwise, whether or not the mode is the lens-auto mode or the lens-manual mode is checked. If the mode is 'the lens-auto, the auto lens KALens bit is set and the control is returned (steps S34-~-S36, 539, S41, S42).
If the mode is the lens-manual and if the levels of the pins Fmaxl and Fmax2 are "11" and the levels of the pins Fmin1-~- Fmin3 are "111", the no lens flag (NoLens bit) is set and control is returned, since the taking lens is not attached to the camera body (steps S43 and S44).
io If the mode is the lens-manual mode and if the levels of the pins Fmax 1 and Fmax2 are "00" and the levels of the pins Fminl-v Fmin3 are "000", the lens is the manual lens FC, and accordingly the manual lens flag (KLens bit) is set and the control is returned (steps S45 and S46).
t5 Unless the levels of the pins Fmaxl Fmax2, Fminl~-Fmin3 are all "1" or "0", the len;a is the auto lens KALens in the lens-manual mode, and accordingly, the auto lens KAlens bit is set arid the control is returned (steps 541, S43, S45 and S42).
2p Thus, the type of lens, the lens data, and the lens Auto/Manual data are set in the memory of the IPU 43 and are transferred to the CPU 41.
Figure 28 shows a sub-routine of the switch input operation at step 5224. If any one of the drive switch 25 SWDRIVE, the ISO sensitivity setting switch SWISO, the exposure correcting switch SW ~ EF, and the exposure mode sw itch SEMODE is turned ON, the operation in the corresponding sub-routine (note: only the mode shift and MODE IN sub-routines are shawn in Fig. 28) is performed (steps S231 ~-5233). Upon completion of the input operation, the mode shift operation, the MODE IN
operation, and the memory lock operation are effected and the control is returned (steps 5234 -~-5236). The mode shift sub-routine, the MODE IN sub-routine and the memory lock to sub-routine will be discussed hereinafter.

Operation of Electronic Dials Figures 29 and 30 show the sub-routines of the operations of the 'fv and Av electronic dials 17 and 19. The main routine is interrupted by these sub-routines when the Tv or Av electronic dial I7 or 19 is rotated, so that any one of the ports PAO, PA1, PA2, PA3 is turned ON to set the associated Tv or Av dial change bit (steps 5271, 5281).
When the Tv electronic dial 17 is rotated, the direction of the rotation of the Tv electronic dial 17 is to checked at step 5272. If the Tv electronic dial i7 is rotated in the right (clockwise) direction, the port PAO is set at "0" (the port PA1 remains at "1"), the clockwise rotation bit is set, and if the Tv electronic dial 17 is rotated in the left (counterclockcaise) direction, the port t5 PA1 is set at "0" (the port PAO remains at "1"), the right .
direction bit is reset, and then the control is returned (steps 5273 and 5274).
Similarly, when the Av electronic dial 19 is rotated, the Av dial change bit is set, and the right direction bit 2o is set or reset (steps 5282 -~-5284). The electronic dial change bits and the right direction bits are used in the setting operations of the Av and Tv electronic dials 17 and 19 and the exposure mode selecting operation, etc., which will be explained below.

Setting of Tv, Av Electronic Dials The following discussion will be addressed to the operation of the IPU 43 in accordance with the sub-routine shown in Figs. 31 and 32 when the electronic dial 17 or 19 s is actuated in a specific exposure mode.
The specific exposure mode in the illustrated embodiment is either the program mode, the limited program mode, the hyper-program mode, the EE automatic mode, the lens-auto ES automatic mode, or the manual mode.
1o Furthermore, in the illustrated embodiment, the shutter capacity of the camera is 30 sec. ~- 1/8000 sec. (Tv= - 5Tv -~-+ l3Tv) and the diaphragm capacity is the open F number Fmin (=Avmin) read from the taking lens through the maximum F number Fmax (=Avmax). For clarification, it is assumed 15 that Tv and Av are both 1/2Ev.
Concerning the Tv dial check, the Tv dial change bit is first checked. If the bit is "0", the control is directly returned, and if the bit is "1", whether or not the right direction rotation bit is set is checked (steps 20 5401, 5402). If the right direction rotation bit is set (i.e., the Tv electronic dial 19 is rotated in the right direction), the shutter speed Tv is increased to the maximum shutter speed Tvmax 1/2 Tv by 1/2 Tv (steps 5402, 5403, 5404). Conversely, if the right direction rotation 25 bit is reset (i.e., the Tv electronic dial 19 is rotated in a~~~.~'uv ~~
the left direction), the shutter speed Tv is decreased 1/2 Tv by 1/2 Tv until the minimum shutter speed Tvmin is reached (steps 5402, 5405, 5406). Thereafter, the Tv dial change bit is cleared and the Tv right direction rotation bit is reset (step 5407).
With respect to the Av dial check, if the Av electronic dial 17 is rotated in the right direction, the diaphragm value Av is increased 1/2 Av by 1/2 Av until the maximum diaphragm value Avmax is reached (steps 5411~-io 5414). Thereafter, the Av dial change bit is cleared and the Av right direction rotation bit is reset (step 5418).
Conversely, if the Av electronic dial 17 is rotated in the left direction, the diaphragm value Av is decreased 1/2 Av by 1/2 Av until the minimum diaphragm value Avmin is 15 reached (steps 5411, 5412, 5415, 5416). Thereafter, the Av dial change bit is cleared and the Av right direction rotation bit i.s reset (step S418), and the control is returned. The sub-routines of figures 31 and 32 are called at the Tv dial set and the Av dial set, respectively, which z0 will be discussed hereinafter.
Selection of Exposure Mode Figures 33, 34A and 34B show sub-routines of the selection or modification operation of the exposure modes.
z5 The change of the exposure modes is effected by the IPU 43 in acr_ordance with the program memorized in the internal ROM 43a of the IPU 43.
Mode Shift The mode shift operation is effected to convert the IPU exposure mode to the CPU exposure mode. Namely, the IPU
mode which is used in the IPU 43 is converted to the CPU
mode which is used in the CPU 41. Table 4 (attached to the last page of the specification) shows a relationship between the IPU mode N0. and the CPU mode No.
to In the mode shift operation (Fig. 33), the IPU 43 checks the lens diaphragm mode. If the lens diaphragm mode is a manual mode, the CPU mode is set to be the lens-manual mode (i.e., one of IPU modes LB (0-~-2) is set as the CPU
mode) and the control is returned (steps 5621 and 5623). If the hyper-Tv flag and the hyper-Av flag are both cleared in the lens--auto mode, the CPU mode corresponds to the lens-auto mode plus 8, and the control is returned. If the hyper-Tv flag is set, the CPU mode is set at "8", and the control is returned (steps 5621, 5625, 5629 and 5631), . Mode-In The mode-in operation (step 5235) is performed as a sub-routine of the SW-IN operation (step 5224) when the exposure mode/drive lever 29 is moved to the MODE side i.e., when the exposure mode switch SWMODE is turned ON, during the intermittent operation by the 32 ms timer. The variation of the exposure modes is effected by the Tv electronic dial 17 when the exposure mode/drive lever 29 is moved to the MODE side. The exposure modes corresponding to the exposure mode numbers are shown in Table 4 mentioned above.
The mode-in operation will be described below in more detail with reference to Figs. 34A and 34B. The hyper-EE
and hyper-ES modes have no independent mode No. and have an exposure mode No. (14) which is the same as that of the hyper program. The hyper-EE and hyper-ES modes can be discriminated by the Hyp-TV and Hyp-Av flags, respectively.
The taking ler_s in the illustrated embodiment has, an auto/manual selection switch SWAM which is actuated by the diaphragm ring thereof. When the auto/manual selection switch SWAM is moved to the manu:~l side, the diaphragm is set on the taking lens side. If the lens-manual mode is detected at step 5241, the control proceeds to step 5242 to select a desired exposure mode from among the LM diaphragm priority (ESl automatic exposure mode (exposure mode No.
2), the LM hyper-manual exposure mode (exposure mode No. 1) and the LM bulb exposure mode (exposure mode No. 0). The LM
diaphragm priority automatic exposure mode (exposure mode No. 2) is the initial exposure mode.
At step 5242, whether or not the mode switch SWMODE
is turned ON is checked. If the mode switch SWNIODE is turned ON, whether or not the Tv electronic dial 17 is actuated (i.e., the Tv dial change bit is set) is checked.
If there is no change, the Tv dial change bit is reset, and the control then proceeds to the checking sub-routine.
If there is a dial change, the direction of rotation of the dial is checked (steps 5243, S244 and S251).
When the Tv electronic dial 17 is rotated ~in the leftward direction (counterclockwise direction), i.e., if the right direction bit is "0", the exposure mode is to switched from the LM diaphragm priority mode to the LM
hyper-manual mode and the LM bulb mode in this order one by one. After the Tv dial change bit is reset, the control jumps to the check sub-routine (steps 5241 ~-5247 and 5251).
When the Tv electronic dia:L 17 is rotated in the right direction (the right direction bit is "1"), the exposure mode is changed in the order opposite to the above-mentioned order. After the Tv dial change bit is reset, the cone rot jumps to the check sub-routine (steps 5244, 5248- 5251 ) .
If the exposure mode switch SWMODE is turned OFF, or if the Tv electronic dial 17 is not actuated (the Tv dial change bit is "0"), the Tv dial change bit is reset without modifying the exposure mode, so that the control jumps to the check sub-routine (steps 5242, 5243 and 5251).

~~~ a~~~'~
Check Sub-routine In the check sub-routine, if one of the NOLens bit flag, the hyper-Av flag, or the hyper-Tv flag is set, the mode indication operation is carried out after the hyper-Av flag and the hyper-Tv flag are reset. The hyper-Av flag and the hyper-Tv flag represent the AE mode.
Namely, although the hyper-EE mode and the hyper-ES mode are not included in the types of AE modes, the hyper-EE
io mode and the hyper-ES mode can be discriminated by the hyper-Av flag and the hyper-Tv flag, respectively.
Consequently, the hyper program No. 14 and the hyper Tv flag are set in the hyger-EE mode, and the hyper program No. 14 and the hyper Av flag are set in the hyper-ES mode, respectively.
To return the mode from the hyper-EE mode or hyper-ES
mode to the respective hyper program modes, the hyper-Av flag or the hyper Tv flag is reset. The hyper-Av flag and the hyper-Tv flag are always reset in the lens-manual mode 2o by the check sub-routine, and accordingly, when the auto/manual selection switch SWAM is switched from "MANUAL" to "AUTO", or when the taking lens is detached from, and again attached to the camera body, the exposure mode is initialized to be the hyper-program exposure mode.
If the taking lens is 'the auto-lens, and accordingly, the auto/manual selection switch SWAM is switched to "AUTO", the exposure mode is switched mode by mode in the order: program mode-. hyper-program mode-. limited program mode- ...-~ LA bulb mode--~ program mode. The s exposure mode is indicated (steps 5241, 5251-5257, 526~~), when the exposure mode switch SWMODE is turned ON and the 'fv electronic dial 17 is rotated in the leftward direction.
If the Tv electronic dial 17 is rotated in the right direction, the exposure mode is changed in the order to opposite to the above-mentioned order and is then indicated (steps S258 ~-5260 and 5264).
If the taking lens is an auto-lens and if one of the exposure mode switch SWMODE or the Tv electronic dial 17 is turned OFF, exposure selection operation is not effected 15 (steps S241, S251 -v 5253, 5261). :Lf the clear button 23 is not turned ON (i.e., clear switch SWGL is not turned ON), the latest exposure mode is indicated (steps 5261 and 5264).
If the clear button 23 is turned ON, and if the exposure mode is the hyper-EE mode or the hyper ES mode, 2a the exposure mode is initialized to be the hyper-program made. If the exposure mode is neither the hyper-EE mode nor the hyper ES mode, the current exposure mode is maintained.
Namely, since the hyper-Tv flag or the hyper-Av flag is set when the exposure mode is the hyper-EE mode or the 25 hyper-ES mode, the flag is reset (steps 5261 and 5263).

Consequently, when the photographer presses the clear button 23, the hyper-EE automatic exposure mode or the hyper-ES automatic exposure mode is returned to the hyper-program exposure mode.
In the exposure mode selection operation mentioned above, it is impossible to directly select the hyper-EE or hyper-ES automatic exposure mode. The selection of the hyper-EE or hyper-ES automatic exposure mode is effected by 'the electronic dial 17 or 19 when the hyper-program io exposure mode is selected. Namely, when the electronic dial 17 or 19 is actuated at the hyper-program mode, the hyper-Tv .flag or the hyper-Av flag is set, so that the mode can be compulsively changed to the hyper-EE or hyper-ES
automatic exposure mode. Furthermore, when the electronic a~~ dial 17 or 19 is actuated at the hyper-EE or hyper-ES
program mode, the mode can be compulsively changed to the hyper-ES or hyper-EE automatic exposure mode, respectively.
If the clear button 23 is turned ON, the hyper-EE or hyper-ES automatic exposure mode can be compulsively 2o changed to the respective hyper-program exposure modes. The indication of the compulsive change of the exposure mode is performed in the exposure mode indication operation which will be discussed hereinafter.
In the illustrated embodiment, the exposure modes in 25 the lens-auto mode and the lens-manual mode are designated ~~~w~~~'~
with serial numbers. However, in practice, the exposure modes in the lens-auto mode and the exposure modes in the lens-manual mode are stored in the memory of the IPU 43 as separate data. Furthermore, the lens-auto/lens-manual (A/M) data, the Hyp-Tv flag and the Hyp-Av flag are separately allocated in the memory of the IPU 43, as can be seen in Fig. 36.
The exposure mode is determined in accordance with the 3-bits for the lens-auto mode and the Hyp-Tv or Hyp-Av io flag when the auto/manual data (A/M terminal), which is sw itched by the diaphragm ring of the taking lens, is "AUTO", i.e., "0". On the other hand, when the auto/manual data (A/M terminal) is "MANUAL", i.e., "1", the exposure mode is determined in accordance with the 2-bits for the i5 lens-manual mode.
The exposure mode data of 4-bits including both the auto exposure mode and the manual exposure mode is sent to the CPU 41. The c~r.respondence in the exposure modes (IPU
mode and CPU mode) between the IPU and CPU is shown in 20 Table 4 listed above.
Memory Lock In the memory lock operation, the exposure value Ev is locked in the memory when the hold button 25 is pressed 25 once and the lock is released when the hold button 25 is ~~~~~b~
pressed tcaice. Namely, every time the hold button 25 is turned ON and OFF, the memory lock of the exposure value Ev and the release thereof are repeated. For example, 3 bits within the memory lock flag data in the RAM 43b are employed in the memory lock operation. As can be seen in Fig. 38, one bit is the ML mode flag (hold bit), another bit the present hold switch data, and another bit the old hold switch data. All of these data are cleared at the initial state.
i0 The memory lock operation at step 5236 is performed as follows (Fig. 37). In this operation, every time the hold switch 25 is ON and OFF, the ML mode flag is set and reset.
First, 'the present hold switch data is transferred to ~.5 'the old hold switch data, so that the ON/OFF state of the hold switch 25 is input to the present hold switch data (steps 5641 and 5643). Namely, when the hold switch is turned ON and OFF, the ML mode flag is set at "0" and reset at "1", respectively. The hold switch 25 is a normally open 2o self-returning type. Generally speaking, since the processing time of the microcomputer is extremely short, the memory lock sub-routines are repeated several times while the photographer actuates the hold switch 25.
Thereafter, the state of the present hold switch data 25 is checked (step 5645). Since the ML mode flag is reset ~~~~~"~°~~
when the hold sw itch 25 is turned OFF, the control proceeds to the memory lock indication operation. Since when the hold switch 25 is turned ON, the ML mode flag is set, the control proceeds to step 5647 to check the old hold switch data. Upon the first operation when the hold switch 25 is turned ON, or upon the second and subsequent operationswhen the hold switch 25 is turned OFF', the ML mode flag is reset, and accordingly, the control proceeds to step 5651.
Upon the second and subsequent operations when the hold to switch 25 is turned ON or upon the first operation when the hold switch 25 is turned OFF, the ML mode flag is set, and accordingly, the control proceeds to step 5649.
Whether or not the ML mode flag is set is checked at step 5651. If the ML mode flag is set, the flag is cleared. , i5 If the flag zs cleared, the ML mode flag is set (steps 5655 and 5653). When the ML made flag is set, the current exposure value Ev is stored (locked), and the power hold flag is set for 5 sec. Thereafter, the control proceeds to the ML indication operation (steps S655, 5657 and S659). If 2o the ML mode flag is cleared, the control directly proceeds to the ML indication operation (steps 5651 and 5653).
At step 5649, whether or not the ML mode flag is set is checked. When the hold switch 25 is turned ON, the ML
mode flag is set, and accordingly, the control proceeds to 2s step 5659. Conversely, when the hold switch 25 is turned OFF, the ML mode flag is cleared, and accordingly, the control directly proceeds to the ML indication operation.
In the ML indication operation, the asterisked mark indication flag iS Cleared. If the ML mode flag is reset, the control is returned. If the ML mode flag is set, the asterisked mark indication flag is set, and then the control is returned (steps S663 and 5665). Ll~hen the hold switch 25 is turned off, the present ML switch data, the old ML switch data and the ML mode flag are all cleared.
io Exposure Mode Indication; Mode and Set Value Modification Examples of the indication o.f the LCD panel 69 and the indicator unit 71 within the finder are shown side by side to the left and right, respectively, in Figs. 41A
through 41F, Figs. 42A through 42F, and Figs. 43A through 43C. In Fig. 41A, all the indicating elements (liquid crystal segments) such as letters, marks, symbols and figures, etc., constituting the indication information are 2o shown. Fig. 41B shows the indication (display) when the main switch SWMAIN is turned OFF. The other figures show various indication examples. The relationship between the exposure mode indication operation and the indication (display) will be described below with reference to Figs.
39A through 39D. The exposure mode indication operation is ,y carried out by the IPU 43 in accordance with the program stored in the ~tOM 43a of the IPU 43.
When the taking lens attached to the camera body is an auto-lens, the control proceeds to step 5302 from step 5301 to perform the following operations.
l0 Hyper-Program Exposure Mode If the hyper-program exposure mode is set, but none of the electronic dials 17 and 19 are actuated, the hyper-program exposure mode is indicated as shown in Fig.
42B. Namely, "Hy P" representing the hyper-program exposure mode, "Tv 8000" representing the initial value (1/8000 sec.) of the shutter speed, "Av 5.6" (=F5.6) representing the initial value of the diaphragm value, "22" representing the number of the photographed frames of film all appear in the to LCD panel 69, and the initial values of the the shutter speed Tv and the diaphragm value Av appear in the indicator unit 71 within 'the finder (steps 5302 through 5308).
The IPU 43 reads the optimum shutter speed Tv (transferring shutter speed TVT) and the optimum diaphragm value Av (transferring diaphragm value AVT), calculated in the hyper-program exposure sub-routine by the CFU 41, provided that the power of the CPL1 41 is held (remains on) and stores these data in the RAM 43b at predetermined addresses thereof (steps 5309 and 5310). The transferring shutter speed TVT and the transferring diaphragm value AVT, stared in the RAM 43b are indicated in the LCD panel 69 and the indicator unit 71 within the finder provided that the power of the CPU 41 is held.
When the Tv electronic dial 17 is actuated (i.e., when the Tv dial change bit is set at "1"), the hyger-Tv flag is set and the hyper-Av flag is reset thereby actuating the hyper-EE automatic exposure mode (steps 5303 and 5311). Thereafter, the shutter speed Tv is modified in accordance with the operation of the Tv electronic dial 17, with the modified shutter speed being stored in the RAM 43b at a predetermined address thereof and the hyper-EE
automatic exposure made and the set shutter speed Tv, etc., being indicated in the LCD panel 69 and the finder indicator unit 71, as shown in Fig. 42G (steps S312 and ro 5313 ) .
The initial value of the set diaphragm value Av is a value calculated at the hyper-program exposure mode or the hyper-EE exposure mode. Note that in Fig. 42G, the three quarter circle which surrounds the symbol "Tv" and the two black arrows located above the symbol "Tv", in the LCD
panel, and the line underlining the numeral "4000" in the finder indicator unit 71 repre:>ent the feasibility of the shutter speed Tv modification by rotation of the Tv electronic dial 17.
2o While the power of the CPU 41 is held, the IPU 43 reads (or receives) data (AVT) corresponding to the optimum diaphragm value Av (AVD), calculated in the hyper-EE
automatic exposure sub-routine, and stores the data in the RAM 43b while indicating the same in the LCD panel 69, etc.
(steps S314 and S315).

When the Av electronic dial 19 is actuated (i.e., when the Av dial change bit is "1"), the hyper-Av flag is set and the hyper-Tv flag is reset thereby actuating the hyper-ES automatic exposure mode (steps 5304 and 5316). The s diaphragm value Av is varied in accordance with the direction of rotation of the Av electronic dial 19, so that the modified diaphragm value Av is stored in the RAM
43b. The hyper-ES automatic exposure mode and the modified diaphragm value Av are indicated in the LCD panel 69 and l0 the finder indicator unit 71, as shown in Fig. 42H (steps 5317 and S318).
The initial value of the set diaphragm value Av is a value Calculated in the hyper-program exposure mode or the hyper-EE exposure mode. Note that in Fig. 42H, the three i5 quarter circle which surrounds the symbol "Av" and the two black arrows located below the symbol "Av", in the LCD
panel, and the line underlining the numeral "8.0" in the finder indicator unit 71, represent the feasibility of the diaphragm value Av modification by rotation of the Av 2p electronic dial 19.
The IPU 43 reads data (TVT) corresponding to the optimum shutter speed Tv (TVD) calculated in the hyper-ES
automatic exposure sub-routine and stores the data in the RAM 43b, provided that the power of the CPU 41 is held. The stored data is indicated in the LCD panel 69 and the finder ~~~~~ ~'~
indicator unit 71 (steps 5319 and 5320).
When the hyper-EE oz' ES automatic exposure mode is selected (i.e., when the hyper-Tv or hyper-Av flag has already been set), the IPU 43 stores the optimum transferring shutter speed TVT and the optimum transferring diaphragm value AVT, calculated in the hyper-ES or hyper-EE automatic exposure sub-routine by the CPU 41, into the RAM 43b and displays the same on the LCD
panel 69, etc., even if neither of the electronic dials 17 to or 19 are actuated. Nevertheless, the IPU 43 does not perform the modification of the diaphragm value Av or the shutter speed Tv ( steps S303~- 5305, 5313- 5315 or 5303-~-5306, 5319- 5320).
Thus, 'the photographer can rotate the Tv electronic i5 dial 17 to switch the hyper-program exposure mode to the hyper-EE automatic exposure mode and select the shutter speed Tv. Similarly, it is possible for the photographer to switch the hyper-program exposure mode to the hyper-ES
automatic exposure mode and select the diaphragm value Av 2~ by rotating the Av electronic dial 19. Tn the illustrated embodiment, upon switching exposure modes, the optimum shutter speed or the optimum diaphragm value, calculated in the previous exposure mode, become the initial value of the exposure factor (i.e., the shutter speed or the diaphragm 25 value) which can be set at the newly selected exposure C'~~~~~~
mode. The initial value of the exposure factor, set at the newly selected exposure mode, can again be varied by the subsequent operation of the electronic dial 17 or 19.
Alternatively, it is possible to adopt a control system in which the exposure factors are modified at the time the exposure mode is changed.
As can be understood from the above discussion, the mode can be switched from the hyper-EE automatic exposure mode or the hyper-ES automatic exposure mode to the hyper to program exposure mode when the clear button 23 is turned ON. The change from the hyper-EE automatic exposure mode to 'the hyper-ES automatic exposure mode and vice versa can be effected by the rotation of the Av electronic dial 19 and the Tv electronic dial 19, respectively. In the a5 illustrated embodiment, when the hyper-program exposure mode is selected, the diagrams shown at a solid line, a dotted line and a dotted and dashed line in Fig. 10 can be easily obtained by actuating the clear button 23 and the electronic dials 17 and 19, respectively.
2.0 As mentioned above with reference to Figs. 33 and 34, the hyper Tv and Av flags are released when either the clear button 23 is turned ON (steps S261-~.~5263), the hyper-program exposure mode is selected, the main switch SWMAIN is turned OFF or the taking lens is detached from 25 the camera body. When the main switch SWMAIN is turned on ~rC~~~~:~
or when the taking lens is attached, the mode is returned to the initial mode, i.e., the hyper-program automatic exposure mode.
Program Exposure Mode When the ordinary program exposure mode is selected, "P", which represents the program exposure mode, is indicated in the LCD panel 69 (steps 5301, 5302, 5321 5323). Furthermore, when the power hold of the CPU 41 is to effected, the IPU 43 reads the communication TVT, AVT data corresponding to the the optimum shutter speed Tv and the optimum diaphragm value Av, calculated in the program exposure sub-routine, and stores the data in the RAM 43b.
The data is indicated in the LCD panel 69, etc., as shown in Fig. 42A (steps 5324 and 5325).
Limited Program Exposure Mode In the limited program exposure mode, the ghotographer can modify the upper and lower limits of the 2o shutter speed and the diaphragm value, both varying along the program diagrams, by actuating the electronic dials 17 and 19 and the hold switch 25.
Selection of the limited program exposure mode is indicated by illuminating the three quarter circle surrounding the symbols "Av" and "Tv", as shown in Fig. 41C

(steps 5461 and 5462).
When the clear switch SWCL is turned ON, the lower and upper limits 'PV1 and TV2 of the shutter speed and the lower and upper limits AV1 and AV2 of the diaphragm value s are initialized (steps 5463-1, 5463-2). The initial values of the shutter speed limits and the diaphragm value limits at the limited program exposure mode in the illustrated embodiment are as follows. Namely, TV1=TVMIN=30 (sec.); TV2 =TVMAX=1/8000 (sec.), AV1=AVMIN; AV2=AVMAX. These initial to values are set when the limited program exposure mode is selected for the first time after the battery is charged.
If the clear switch SWCL is turned OFF, the control proceeds to step 5464 to check the photometering switch SWS
without initializing the shutter speed limits TV1 and TV2 i5 and the diaphragm value limits AV1 and AV2. Namely, the limits set by the photographer in accordance with the following processes are initialized when the clear button 23 (clear switch SWCL) is turned ON.
When the photometering switch SWS is turned ON or 2o when the power is held, even if the photometering switch SWS is turned OFF, the control proceeds to step 5485 (steps 5464, 5465-1). When the photometering switch SWS is turned OFF and when the power of the CPU 41 is held, the limit value is modified, and the control then proceeds to step 2s 5485 (steps 5465-1, 5465-2, 5466-5486). At step 5485, ~~ ~.a~~~~
whether or not the power of the CPU 41 is held is checked.
If the power is held, the CPU 41 reads the optimum diaphragm value Av anti the optimum shutter speed Tv calculated at the limited program exposure mode and stores the data in the RAM 43b. The data is indicated in the BCD
panel 69, etc. Thereafter, the control is returned. If the power is nat held, the control is directly returned (step 5486).
Change of the limit values is effected as follows to (step 5465-2 and steps subsequent thereto).
When the Tv electronic dial 17 is actuated, the limits of the shutter speed Tv are increased or decreased in accordance with the direction of the rotation of the Tv electronic dial 17. The limits are stored in the RAM 43b and indicated (steps 5465-2, 5466).
When the hold button 25 is turned ON, the upper and lower limits TV1 and TV2 of the shutter speed are set.
Namely, when the hold button 25 is turned ON for the first time or an odd number of times, since the ML mode flag is 2o set, the set Tv data is modified to the lower limit TV1 (steps 5467 5470), and when the hold button 25 is turned ON the second time or an even number of times, the set Tv data is modified to the upper limit TV2, and the control proceeds to step 5485 (steps 5467, 5468, S469,S472). If the hold button 25 is not turned ON, change of the shutter ~~~v~~~~
speed is not effected (steps S467, 5485).
On the other hand, when the Av electronic dial 19 is turned ON, the limits of the diaphragm value are changed simultaneously with the limits of the shutter speed Tv.
Namely, the diaphragm value is increased or decreased in accordance with the direction of rotation of the Av electronic dial 19. The diaphragm value is consequently stared in the RAM 43b and indicated in the LCD panel 69, etc., (steps 5475, 5476). If 'the hold button is turned ON
to for the first time or an odd number of times, since the ML
mode flag is set at "1", the set Av data is modified to the lower limit AV1, and when the hold button 25 is turned ON
the second time or an even number of times (M1 mode flag is "0"), the set Av data is modified to the upper limit AV2, is and the control proceeds to step S485 (steps 5478, 5479, 5482).
Upon completion of the modification of the limits TV1 and TV2 and AV1 and AV2 of the shutter speed and the 2o diaphragm value, the CPU 41 reads the optimum shutter speed Tv and diaphragm value Av calculated in the limited program exposure mode and stores the data in the RAM 43b, provided that the power of the CPU 41 is held (steps 5485, 5486).
The stored data is indicated in the LCD panel 69 and the 25 indicator unit within the finder.

As can be understood from the foregoing, in the limited program exposure mode, the shutter speed and the diaphragm value set by the photographer axe changed to the upper or lower shutter speed limit and the upper or lower diaphragm limit when the hold switch 25 is turned ON. In an alternative, to change the shutter speed limits or the diaphragm limits every time the electronic dial 17 or 19 is actuated, it is possible to skip the operations at steps 5467 and 5477.
io LA ES Automatic Exposure Mode When the body-set diaphragm priority (ES) automatic exposure mode (lens-auto ES automatic exposure mode) is selected, the LCD panel 69 and the indicator unit 71 i5 within the finder are displayed as shown in Fig. 42D (steps 5301, 5302, 5321, 5461, 5331-5333). When the Av electronic dial 19 is rotated, the diaphragm value Av is increased or decreased in accordance with the direction of rotation thereof, stored as the set diaphragm value Av in the RAM
20 43b, and indicated in the LCD panel 69, etc. When the power of the CPU 41 is held, the IPU 43 outputs the diaphragm value AVT, calculated in the diaphragm priority automatic exposure mode, to the CPU 41 which reads the optimum shutter speed Tv calculated in the LA diaphragm priority 25 automatic exposure sub-routine, stores the data in the RAM

43b and indicates the same in the LCD panel 69, etc. (steps 5334- 5338 ) .
LA EE Automatic Exposure Mode When the shutter speed priority (EE) automatic exposure mode is selected, the display of the LCD panel 69 arid the indicator unit 71 within the finder is as shown in Fig. 42C, in which the initial value (1/$000 sec.) of the shutter speed Tv appears (steps S301, 5302, S321, S331, 5341~-io S343). When the Tv electronic dial 17 is rotated, the shutter speed T~ is increased or decreased in accordance with the direction of rotation thereof, stored as the set shutter speed Tv in the RAM 43b, and indicated in the LCD
panel 69, etc. When the power of the CPU 41 is held, the IPU 43 outputs the shutter speed TVT calculated in the shutter speed priority automatic exposure mode to the CPU
41 which reads the optimum transferring diaphragm value AVT
calculated in the EE automatic exposure sub-routine, and stores the data in the RAM 43b and indicates the same in 2o the LCD panel 69, etc., respectively, as shown in Fig. 42C
( steps 5344 -r 5348 ) .
Hyper-Manual Exposure Mode In the hyper-manual exposure mode in the illustrated embodiment, the function equivalent to the calculation of the shutter speed Tv and/or the diaphragm value Av in the program exposure mode, the EE automatic exposure mode or the ES automatic exposure mode is achieved by actuating the clear button 23.
When the body-set hyper-manual exposure mode is selected, the display of the LCD panel 69, etc., is as shown in Fig. 42E (steps S30:L, S302, 5321, S461, 5331, 5341, 5379 5351). When the Ev check sub-routine is performed, the shutter speed Tv and the diaphragm value Av to which are increased or decreased in accordance with the direction of rotation of the electronic dials 17 and 19 are set in the RAM 43b and indicated i:n the LCD panel 69, etc., respectively (step S352).
If the power of the CPU 41 is held, the shutter speed TVT and the diaphragm value AVT selected in the manual exposure mode are output to the CPU 41, which reads the specific point LED bit calculated in the body-set manual exposure sub-routine, stores the same in the RAM 43b, and controls the illumination of the exposure indicating 2o elements 71a and 71b (steps 5353-~-5360).
LA Bulb Exposure Mode When the body-set bulb exposure mode is selected, the display of the LCD panel 69, etc., is as shown in Fig. 42F
(steps 5301, 5302, 5321, 5461, S331, 5341, 5349, 5361, 5362).

When the Av electronic dial 19 is rotated, the diaphragm value Av is increased or decreased in accordance with the direction of rotation of the Av electronic dial 19, stored in the RAM 43b, and indicated in the LCD panel 69 and the indicator unit 71 (steps 5363 ~-5365).
In the body-set shutter priority exposure mode, diaphragm priority exposure mode, manual exposure mode and bulb exposure mode, as mentioned above, the photographer can set the shutter speed Tv and the diaphragm value Av by to actuating the electronic dials 17 and 19. In this case, the three quarter circle, the arrows, and the letters "Tv" and "Av" appear in the LCD panel 69. Also, the shutter speed Tv or the diaphragm value Av is underlined, as mentioned above. Accordingly, the photographer is alerted that the shutter speed Tv and the diaphragm value Av can be manually set by actuating the electronic dials 17 and 19, .respectively.
Furthermore, when the hold button 25 is turned ON, the asterisk mark of the indicating element 71c is 2o illuminated in the indicator unit 71 within the finder, and accordingly, the photographer is alerted that the memory is locked.
Lens-Manual Mode Indication of the exposure mode in the lens-manual mode, in which the diaphragm value is set on the taking lens side, is effected by the IPU 43 as follows:
LM hyper-Manual Exposure Mode Selection of the LM hyper-manual exposure mode is indicated in the LCD panel 69, etc., as shown in Fig. 43A
(steps 5301, 5371 -~-5373). When the Tv electronic dial 17 is rotated, the shutter speed Tv which is increased or decreased in accordance with the direction of rotation ~o thereof is stored in the RAM 43b as the set shutter speed Tv and indicated in the LCD panel 69 and the indicator unit 71 within the finder (steps 5374-5376).
Furthermore, when the power of the CPU 41 is held, the shutter speed TVT and the diaphragm value AVT selected in the manual exposure mode are output to the CPU 41 which reads the exposure indication bit set in the LA manual exposure sub-routine, stores the read data in the HAM 43b, and controls the illumination of the indicating elements 71a and 71b (steps 5377 and 5378). Figs. 43A, (a), (b) and (c) designate optimum exposure, over exposure, and under exposure, respectively.

LM Manual ES Automatic Exposure Mode The lens-maraual diaphragm priority (ES) automatic exposure mode is indicated in the LCD panel 69, as shown in Fig. 43B (steps 5301, 5381-5383). If the power of the CPU
41 is held, the CPU 41 reads the shutter speed TVT
calculated in the lens-manual ES automatic exposure sub-routine and stores the data in the RAM 43b. The data is indicated in the LCD panel 69, etc., and the control is returned (steps S384, 5385).
LM Bulb Exposure Mode When the lens-set bulb exposure mode is selected, the shutter speed Tv is set at "B" (bulb) which is indicated in the LCD panel 69, as shown in Ficfi. 43C (steps 5301, S371, 5381, 5391, 5392).
Ev Checking Sub-Routine In the Ev check operation, when the hold switch 25 is turned ON, the optimum exposure value at that time is locked, and if the electronic dial 17 or 19 is actuated thereafter, the associated exposure factor (shutter speed or diaphragm value) is increased or decreased in accordance with the direction of rotation of the electronic dial 17 or 19, and the other exposure factor (diaphragm value or shutter speed) is decreased or increased, respectively, to retain the locked exposure value. In the Ev checking sub-routine at step S352, every time the electronic dial 17 and 19 are rotated by one step when the hold button 25 is turned ON, the increment ar decrement of the shutter speed Tv and the diaphragm value Av by 1/2 Tv and 1/2 Av takes place, respectively. The Ev checking sub-routine will be discussed below with reference to Fig. 40.
The RAM 43b of the IPU 43 has a hold bit io corresponding to the switching operation of the hold button 25. If the hold bit is "0", i.e., if the hold button 25 is not turned ON, the shutter speed Tv and the diaphragm value Av, which have already been set are not modified (steps 5421, 5437). Conversely, if the hold bit is "1", i.e., if the hold button 25 is turned ON, 'the following operation is performed.
If the Tv electronic dial 17 is rotated in the leftward direction (counterclockwise direction) by one step or more (i.e., the Tv change bit is "0") the shutter speed 2o Tv is decreased 1/2 Tv by 1/2 Tv and the diaphragm value Av is increased 1/2 Av by 1/2 Av until the shutter speed Tv is equal to- 5 (Tv=- 5 ~- 30 sec.) or the diaphragm value Av is equal to the maximum diaphragm value AVMAX (steps 5422 5427). If the Av electronic dial 19 is rotated in the rightward direction (clockwise direction), the same 'p~E~~ ~b~~b~
operation as above is performed (steps 5422, S428, 5429, 5424--- 5427 ) .
If the Tv electronic dial 17 is rotated in the rightward direction (clockwise direction), the shutter speed Tv is increased 1/2 Tv by 1/2 Tv and the diaphragm value Av is decreased 1/2 Av by 1/2 Av until the shutter speed Tv is equal to 13 (Tv=13~-1/8000 sec.) or the diaphragm value Av is equal to the minimum diaphragm value AVMIN (steps 5422, 5423, S430 -~-5433). Tf the Av electronio l0 dial 19 is rotated in the leftward direction (counterclockwise direction), the same operation as above is performed (steps S422, 5428-~.-5433). The increased or decreased shutter speed Tv and the diaphragm value Av are stored in the RAM 43b and the Tv, Av change bits are reset ( steps 5434 -~ 5437 ) .
Thus, both the shutter speed Tv and the diaphragm value Av can be simultaneously adjusted by actuating one of the electronic dials 17 or 19 while maintaining the exposure value Ev constant, when the hold button 25 is 2o turned ON after the optimum shutter speed and the diaphragm value are manually set. For instance, on the assumption that the optimum shutter speed Tv and diaphragm value Av are 1/125 sec. , and F8.0, in the hyper--manual mode, respectively, if the hold button 25 is turned ON, the memory is locked. Thereafter, if for example the Tv electronic dial 17 is rotated by two steps, the shutter speed Tv and the diaphragm value Av are changed to 1/60 sec., and F11, resper_-tively, while maintaining exposure at the optimum value. For comparison's sake, if the Tv electronic dial Tv is actuated at the ordinary hyper-manual exposure mode, only the shutter speed is varied, resulting in a change in exposure value. This mode will be cancelled when the hold button is actuated again.
to Second Exposure Mode Indication Operation The second exposure mode indicating operation is different from the first exposure mode indicating operation in that the exposure mode can be changed only when the electronic dials 17 or 19 are rotated by more than two i5 steps in the hyper-program exposure mode.
When neither of the electronic. dials 17 or 19 is actuated and both the hyper-Tv and hyper-Av flags are "0"
in the lens-auto hypes-program mode (i.e., when the hyper-program exposure mode is selected) the display in the 2.o LCD 69 and the indicator unit 71 within the Finder is as shown in Fig. 42B (steps 5501 -~-S50g). The transferring shutter speed TVT and the transferring diaphragm value AVT, calculated by the CPU 41, are stored in the RAM 43b (steps 5509, 5510), provided that the power of the CPU 41 is held.
25 When the hyper-EE automatic exposure mode is ;~~~~~~r selected, the control proceeds from step 5505 to step 5514, since the hyper-Tv flag is set. Thereafter, in steps 5514 5518, the operations similar to those in steps 5311 -v 5315 are effected. On the other hand, if the hyper ES automatic exposure mode is selected, the control proceeds from step 5506 to step 5524, since the hyper-Av flag is set.
Thereafter, in steps 5524 ---552.8, the operations similar to those in steps 5316 ~-5320 are effected.
When the Tv electronic dial 17 or the Av electronic io dial 19 is rotated, namely, when the Tv-change bit or the Av-change bit is "1", the operations in the Tv dial or Av dial checking sub-routine are effected. As can be understood from the foregoing, in the Tv dial or Av dial checking sub-routine, the exposure mode is changed only when the Tv or Av electronic dial 17 or 19 is rotated by two or more steps in the same direction.
When the Tv or Av electronic dial 17 or 19 is rotated by one step in a predetermined direction, or when the Tv or Av electronic dial 17 or 19 is rotated thereafter by one 2o step in the opposite direction, the control proceeds to step 5505 (steps 5503, S511, S505 or steps 5503, 5521, 5505).
When the Tv electronic dial 17 is rotated by two steps in the same direction, the control proceeds from step 5511 to step 5512 in which, if the hyper-Tv flag is "0", the ~~,~~~°~~"~
Tv dial change flag is reset to permit the mode to be changed to the hyper-EE automatic exposure mode and prevent the shutter speed Tv from being changed, since the hyper-EE
automatic exposure mode is not selected. Thereafter, the control proceeds to step 5514 (steps S512, S513 and 5514).
If the hyper-Tv flag is "1", since the hyper-EE automatic exposure mode is selected, the control proceeds directly to step S514 in which the shutter speed Tv can be adjusted (steps 5512, 5514).
io On the other hand, when the Av electronic dial 17 is rotated by two steps in the same direction, the control proceeds from step 5521 to step 5522 in which, if the hyper-Av flag is "0", the Av dial change flag is reset to permit the mode to be changed to the hyper-ES automatic exposure mode and 'prevent the diaphragm value Av from being changed, since the hyper-ES automatic exposure mode is not selected Thereafter, the control proceeds to step 5524 (steps 5521, 5522, 5523, 5524). If the hyper-Av flag is "1", since the hyper-ES automatic exposure mode is 2o selected, the control proceeds directly to step 5524 in which the diaphragm value Av can be adjusted (steps 5521, 5522, 5524).
The Tv, Av dial check sub-routines will be discussed below with reference to steps 5511 and 5521 in Figs. 45 and 25 4g, In the Tv dial check sub-routine, whether or not the Tv dummy flag is "1" is checked at step 5551. Since the Tv dummy flag is not initially set, the Tv dummy flag is set and the old Tv dial direction flag is replaced with the present Tv dial direction flag, and the control is then returned to step 5505 (step 5552). The second time through the sub-routine, if the direction of rotation of the Tv electronic dial 17 is the same as that of the first notation, the Tw dial dummy flag is set and the Av dial dummy flag is reset, since the present Tv dial direction io flag is identical to the old Tv dial direction flag (steps 5553, 5555), After that, the control proceeds to step 5512.
Conversely, if the direction of the second rotation of the Tv electronic dial 17 is different from that of the first rotation, the Tv dial dummy flag is reset and the old Tv dial direction flag is replaced with the present dial direction flag, since the old Tv dial direction flag is different from the present flag (steps 5551, 5553, 5554). After that, the control proceeds to step 5505.
In the Av dial check sub-routine, whether or not the 2o Av dummy flag is "1" is checked at step S561. Since the Av dummy flag is not initially set, the Av dummy flag is set and the old Av dial direction flag is replaced with the present Av dial direction flag, and the control is then returned to step S505 (step S562). The second time through z5 the sub-routine, if the direction of rotation of the Av electronic dial 19 is the same as that of the first rotation, the Av dial dummy flag is set and the Tv dial dummy flag is reset, due to the fact that the present Av dial direction flag is identical to the old Av dial direction flag (steps S563, 5565). After that, the control proceeds to step 5524.
Conversely, if the direction of the second rotation of the Av electronic dial 19 9.s different from that of the the first rotation, the Av dial dummy flag is reset and the l0 old Av dial direction flag is replaced with the present dial direction flag, since the old Av dial direction flag is different from the present flag (steps 5561, 5563, 5564). After that, the control proceeds to step S505.
As can be understood from the above discussion, according to the second indication sub-routine, since there is no change in the exposure mode, as long as the electronic dial 17 or 19 is not rotated by more than two steps, even if the electronic dial 17 or 19 is rotated accidentally or by mistake, the mode is not changed. In an alternative embodiment, it is possible to realize a control system in which mode change does no take place if the electronic dial 17 or 19 is successively rotated twice within an extremely short space of time.

The following discussion will be directed to an embodiment in which the exposure value Ev can be locked in the lens-manual (lens-set) manual exposure mode, with reference to Figs. 47 through 51.
Figure 47 shows a plan view of a single-lens reflex camera having an exposure control apparatus according to the present invention.
in Fig. 47, the camera body 111 has a grip portion 112. A shutter button 113 is provided on the frontal to partion of the top surface of the grip portion. A Tv electronic dial 114 and an Av electronic dial 115 are provided behind the shutter button 113 and on the upper portion of the back surface of the grip portion 112, respectively.
Bath the Tv electronic dial 114 and the Av electronic dial 115 are in the form of rotary dials which are rotatable in the clockwise and counterclockwise directions.
When the Tv electronic dial and the Av electronic dial are rotated, the shutter speed and the diaphragm value can be ap changed respectively. The adjustment of the diaphragm value by the Av electronic dial 115 is effected when a diaphragm ring 117, provided in a taking lens 116, is adjusted to an automatic position {AUTO) designated by "A". When the diaphragm ring 117 is adjusted to a position other than the z5 AUTO position, i.e., to a position corresponding to a manual exposure control mode, the adjustment of the diaphragm value is effected by rotation of the diaphragm ring 117. The diaphragm ring 117 can be locked at the position AUTO so as not to rotate, and the lock can be released by depressing an unlocking button 119.
A clear button 121 is provided on the upper portion of the back surface of the camera body 111 in the vicinity of the Av electronic dial 115. A hold button 122 is provided opposite side the clear button 121 with respect zo to the finder 118 on the back surface of the camera body 111.
A slidable exposure correction/ISO lever 123 and a slidable exposure mode/drive lever 124, both slidable from a central, neutral position in opposite directions, are provided on the upper surface of the camera body 111 and on the left side of the finder 118. A main switch 125 is provided an the upper surface of the camera body 111 and on the right side of the finder 118 and may be slidably adjusted to occupy three different positions.
Figure 48 shows a circuit diagram of a control unit of a camera system according to the present invention.
A photometering circuit 141 is connected to a CPU 131 through an A/D canverter 142 to which a diaphragm volume 143 is connected. The diaphragm volume 143, associated with the diaphragm ring 117 (Fig. 47) of the taking lens 116, outpwts a diaphragm voltage representing the diaphragm value and corresponding to the angular position of the diaphragm ring 117. The diaphragm voltage is converted to a digital value corresponding to the diaphragm value Av by the A/D converter 142. The digital value is output to the CPU 131. The CPU 131 actuates the A/D converter 142 at a predetermined time, reads the abject brightness signal and the diaphragm value signal set in the taking lens 116, and converts the signals to the corresponding APEX values.
1o A winding motor 144 winds and rewinds the film, and a mirror motor 145 moves a mirror up and down. The operations of the motors 144 and 145 are controlled by the CPU 131 through a motor driving circuit 146.
The IPU 132 is connected to a CPU or RAM of the taking lens 116. The IPU 132 communicates with the taking lens 116 and reads lens data, such as an open F number Fmin, a maximum F number Fmax, a focal length f, etc. The taking lens 116 has a lens-auto/lens-manual selection switch 151 which is effected to switch a manual diaphragm 2o mode to an automatic diaphragm mode and vice versa, in association with the diaphragm ring 117. The lens-auto/
lens-manual selection switch 151 is connected to the IPU
132. The IPU 132 determines the existence of the manual diaphragm mode or 'the automatic diaphragm mode in accordance with the signal input from the lens-auto/

~~~_~,~.~~~.
lens-manual selection switch 151. The "lens-auto mode"
referred to means an automatic diaphragm mode in which the diaphragm value is set on the camera body side, i.e., the stop-down of the diaphragm value continues until the diaphragm value becomes a predetermined value set in the camera body. The "lens-manual mode" referred to means a manual diaphragm mode in which the diaphragm value is manually set by 'the diaphragm ring 117 on the taking lens 116.
1o Input ports of the IPU 132 are connected to a main switch SWMAIN, a photometer switch SWS, a release switch SWR, an exposure mode switch SWMODE, a drive switch SWDRIVE, an exposure correcting switch SWEF, an ISO
sensitivity setting switch SWISO, a clear switch SWCL and a hold switch SWHOLD, respectively. The function of the IPU
132 and the connection thereof to these switches are fundamentally the same as thoSE: in the aforementioned embodiments.
The main switch SWMAIN is associated with the main 2o switch 125. The photometer switch SWS and the release switch SWR are associated with the shutter button 113. The photometer switch SWS is turned ON when the shutter button 113 is depressed by a half step. The release switch SWR is turned ON when the shutter button 15 is depressed by a full step. The exposure mode switch SWMODE and the drive switch ;r, SWDRIVE are associated with the exposure mode/drive lever 124. The exgosure correcting switch SWEF and the ISO
sensitivity setting switch SWISO are associated with the exposure-correction/ISO lever 123. The clear switch SWCL
and the hold switch SWHOLD, which are both normally open, are associated with the clear button 121 and the hold button 122, respectively.
The Tv electronic dial 114 and the Av electronic dial 115 are connected to the IPU 132. Each of the Tv and Av 1o electronic dials 114 and 115 has a click-stop rotation mechanism per se known. For example, a pair of input posts PAO and PA1 are in a floating state at a click-stop position, and when the Tv electronic dial 114 is rotated in a clockwise or counterclockwise direction, the level of one of the input ports first drops to "L", and then, 'the level of the other drops to level "L". Thereafter, the level of the input port which has dropped to level "L" prior to the other is returned to the floating state before the other.
Since the order of change in the level of the input ports 2o PAO and PA1 depends on the rotation of the Tv electronic dial, the IPU 132 can discriminate the direction of the rotation based on the order of change. The same is true for the Av electronic dial 115.
The IPU 132 is connected to an LCD panel 152 which is controlled by the IPU 132 to indicate various photographic information, such as the exposure modes, the shutter speed Tv, the diaphragm value Av, the number of taken frames of a film, etc.
The operation of the embodiment shown in Fig. 47 is as follows (Figs. 49 through 51).
Figure 49 shows a flow chart of the main program.
At step 5601, the initialization on the automatic exposure (AE) is effected. Namely, 'the data necessary far the calculation of the exposure control is read out from 1o the EzPROM of the IPU 132. The control proceeds to step 5603 from step 5602 to check whether or not the release switch SWR has been turned ON during a time interval of 4 ms beginning at a predetermined time. If the release switch SWR has been turned ON, the releasing is carried out at step 5604. If the release switch SWR has not been turned ON
at step 5603, or if 4 ms has not elapsed at step 5602, whether or not there is a lapse o:~ time of 100 ms from the predetermined time, corresponding to 25 4 ms cycles, is checked at step S605. If there is no lapse of 100 ms, the 2o control is returned to step S602. Conversely, if 100 ms has elapsed, the control proceeds to step 5606.
At step 5606, the necessary data is sent to the CPU
131 from the IPU 132. The data includes data which, for example, represents the type of exposure modes, the exposure control modes of the taking lens 116 (lens-auto mode or lens-manual mode), etc.
At step 5607, photometering is effected to calculate the exposure value (Ev) detected in the photometering operation, based on the brightness of an object to be taken. Whether the exposure control mode of the taking lens 116 is the lens-auto mode or the lens-manual mode is checked at step 5608. If the mode is the lens-manual mode, the manual exposure control is effected at step 5610 and if the mode is the lens-auto mode, the automatic exposure io control is effected at step 5611. At step 5612, the indicating data for the LCD panel 152 is input from the CPU
131 to the IPLJ 132.
Figures 50 and 51 show a program of the manual exposure control which is carried out at step S610, i.e., the lens-manual diaphragm priority exposure mode in which the diaphragm value is set by the diaphragm ring 117 of the taking lens 116.
In the manual exposure control, as will be discussed below, the Ev value is fixed when the hold button 122 is depressed. Thereafter, when the diaphragm value is varied by the diaphragm ring 117, the shutter speed is varied in accordance with the fixed Ev value.
Before a picture is taken, as the hold button 122 is not depressed, the Ev value is not Fixed. Consequently, the flag FAEL is not set at "1", the control proceeds to steps 5700, 5701, 5711, and 5712 in this order. At step 5700, the calculating diaphragm value AVVRD is first calculated, based on the diaphragm value AVAfD set by the diaphragm ring 117 and the inherent adjusting value Avadj of the camera body 111. Whether or not the hold button 122 has been depressed is checked at step 5712. If the hold button has not been depressed, the control proceeds to steps 5714 and 5716 before ending. Although the setting operation of the shutter speed Tv is not shown in the program of Figs.
50 and 51, the operations similar to those of steps 5374 through S376 in Fig. 39H are performed to set the shutter speed Tv.
Here, it is assumed that the photographer actuates the Tv electronic dial 113 and the d9.aphragm ring 117 to set 'the shutter speed and the diaphragm value, and then depresses the hold button 122 to fix the Ev value determined by the shutter speed and the diaphragm value.
Thereafter, when the control enters the sub-routine shown in Figs. 50 and 51 for the first time, since the flag FAEL
2o is not set at "1", the control proceeds to steps 5700, S701, 5711, S712 and 5713. At step 5713, the looked Ev value LVDL is obtained by adding the calculating shutter speed TVD, the calculating diaphragm value AWRD and the correction value MND. The correction value MND depends on the taking lens 116. Thereafter, since the hold button 122 is turned ON at step 5714, the control proceeds to step 5715 to set the flag FAEL.
When the program is performed thereafter, the flag FAEL is set, anal accordingly, the control proceeds to steps 5700, 5701, 5702 and S703. At step 5703, the locked Ev value LVDL is substituted for the calculating Ev value LVD.
At step 5705, the calculating diaphragm value AVVRD and the correction value MND are subtracted from the calculating Ev value LVD to obtain the calculating shutter speed TVD.
Thereafter, at step 5706, if the calculating shutter speed TVD is greater than the calculating maximum shutter speed TVDMAX, the calculating shutter speed TVD is set equal to the calculating maximum shutter speed TVDMAX
at step S707. If the calculating shutter speed TVD is less than the calculating minimum shutter speed TVDMIN at step 5708, the calculating shutter speed TVD is set equal to the calculating minimum shutter speed TVDMIN at step 5709.
Thus, the calculating shutter speed TVD is obtained at step 5707 or 5709, so that the CPU 131 controls the shutter in accordance with the shutter speed TVD.
The shutter speed TVD is converted to the communicating shutter speed TVT to be sent to the IPU 132 and is indicated in the LCD panel 152.
As can be seen from the foregoing, in the embodiment z5 of the invention shown in Figs. 48 through 51, when the a a hold button 12.2 is depressed after the shutter speed and the diaphragm value are manually set, the exposure value determined by the shutter speed and the diaphragm value is stored. Thereafter, if the diaphragm value is varied by the rotation of the diaphragm ring 117, the shutter speed is also varied in accordance with the exposure value.
Therefore, the photographer can take a picture at a desired exposure value without manually adjusting the shutter speed every time the diaphragm ring 117 is rotated.
Furthermore, if the hold button 122 is turned OFF, the control proceeds to steps 5711, 5714 and S716 from step S7d2 to reset the flag FAEL, so that the shutter speed Tv and the diaphragm value Av can be independently set.
The hold button 122 is used to ~ix the exposure value i5 not only in the manual exposure control mode but also in the automatic exposure control mode.
As can be understood from the above discussion, according to the present invention, it is not necessary for the photographer to adjust the shutter speed every time the 2o diaphragm ring is rotated in the manual exposure control mode, thus resulting in a simple photographic operation.

'.i table 1 command name content ' number of of bytes command 0 IPU communication check 1 check with IPC

1 CPU transfer1output all data 1 0 ->IPU

2 CPU transfer2output data for indication5 -~IPU

3 IPU transfer1input .all. data 2 0 ->CPU

4 IPU transfer2input lens data 1 0 ->CPU

IPU transfer3input switch data 1 -aCPU

6 IPU transfer4input exposure mode -->CPU

table 'rime(1/sec)T v T v T v T D

6000 1 2. 5 28. 5 1 8 3000 1 1. 5 27. 5 1 7 1500 10. 5 26. 5 16 750 9. 5 25. 5 1 5 350 8. 5 24. 5 14 180 7. 5 23. 5 13 9 0 6. 5 2 2. 5 1 2 45 5. 5 21. 5 11 20 4. 5 20. 5 10 1 0 3. 5 1 9. 5 9 6 2. 5 1 8. 5 8 3 1. 5 17. 5 7 0"7 0. 5 1 6. 5 6 1 ' ' 0 1 6 5 4/8 1''5 -0. 5 15. 5 5 2" -1 15 4 4/8 3" -1. 5 14. 5 4 4" -2 14 3 4/8 6" -2. 5 1 3. 5 3 8" -3 13 2 4/8 1 0" -3. 5 1 2. 5 2 15" -4 12 1 4/8 20" -4. 5 1 1. 5 1 30' -5 1 1 0 4/8 table 3 0.
FNO. Av AvT AvD Av~J augmen-5EV
tation indication classifica-tion 38 10. 10. 15 32 10 10 14 4/8 ~ Fll 27 9. 5 9. 5 14 11 3/8 19 8. 5 8. 5 13 11 1/8 16 8 8 12 4/8 11 0/8 F9.5 13 7. 5 7. 5 12 10 7/8 9. 6. 5 6. 5 11 10 5/8 ' 8 6 6 10 4/8 ~--- 10 4/8 F8 6. 5. 5 5. 5 10 10 3/8 5. 5 5 9 4/8 10 2/8 4. 4. 5 4. 5 9 10 1/8 4 4 4 8 4/8 10 0/8 F6.7 3.5 3.5 3.5 8 9 7/8 2.8 3 3 7 4/8 9 6/8 _ 2.5 2. 5 2.5 7 9 5/8 2 2 2 6 4/8 9 4/8 F5.6 1. 1 5 1. 5 6 9 3/8 1. 1 1 5 4/8 1.2 0.5 0.5 5 table 4 exposure IPt1 mode CPU mode No. N

m o d a lens ' lens B' ( 4 b i t ) A

(3 b i (2 b i t) t) Program ~ 1 5 Hyper Program 6 1 ~

Program LIMIT S 1 3 (Hyper) Manual 2 1 0 LA

Bulb LA 1 9 Hyper EE -Hyper ES

...... g ......

......

...... 3 (Hyper) Manual 1 1 LM

Bulb LM 0 0

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An exposure control apparatus of a camera, comprising:
means for setting a manual setting mode in which a diaphragm value and a shutter speed are manually settable, said diaphragm value and said shutter speed being settable independently of a luminance of an object to be photographed with said camera;
means for locking an exposure value determined in accordance with said diaphragm value and said shutter speed value set in said manual setting mode; and means for varying one of said diaphragm value and said shutter speed based on said locked exposure value, when the other of said diaphragm value and said shutter speed is varied in said manual setting mode so as to maintain constant said locked exposure value.

2. The exposure control apparatus of claim 1, wherein said exposure value locking means comprises a lock switch which is turned ON to lock said exposure value.

3. The exposure control apparatus of claim 2, wherein said exposure value locking means unlocks said exposure value, which has been locked by said exposure value locking means, when said lock switch is turned OFF.

4. The exposure control apparatus of claim 3, wherein said exposure value locking means locks and unlocks said exposure value every time said lock switch is turned ON and OFF, respectively.

5. The exposure control apparatus of claim 1, wherein said exposure value locking means comprises a lock switch for locking and holding said exposure value when said lock switch is turned ON.

6. The exposure control apparatus of claim 1, wherein said exposure value locking means comprises a lock switch for locking and holding said exposure value when said lock switch is actuated by an odd number of operations.

7. The exposure control apparatus of claim 1, wherein said diaphragm value and shutter speed can be increased and decreased as APEX values of a predetermined step.

8. The exposure control apparatus of claim 7, wherein, when said shutter speed is increased by a predetermined value, said varying means decreases said diaphragm value by an equal value when said exposure value is locked by said exposure value locking means.

9. The exposure control apparatus of claim 7, wherein, when said diaphragm value is increased by a predetermined value, said varying means decreases said shutter speed by an equal value when said exposure value is locked by said exposure value locking means.

10. The exposure control apparatus of claim 7, wherein, when said shutter speed is decreased by a predetermined value, said varying means increases said diaphragm value by an equal value when said exposure value is locked by said exposure value locking means.

11. The exposure control apparatus of claim 7 wherein, when said diaphragm value is decreased by a predetermined value, said varying means increases the shutter speed by an equal value when said exposure value is locked by said exposure value locking means.

12. The exposure control apparatus of claim 1, wherein said camera comprises a camera body, and a taking lens that is detachably attached to said camera body.

13. The exposure control apparatus of claim 12, wherein said means for setting a manual setting mode comprises means, provided in said camera body, for manually setting said shutter speed and means, provided in said taking lens, for manually setting said diaphragm value.

14. The exposure control apparatus of claim 13, wherein said camera body further comprises means for manually setting said diaphragm value.

15. The exposure control apparatus of claim 14, wherein said means for manually setting said diaphragm value provided in said taking lens comprises a diaphragm ring rotatable between a first position, in which said diaphragm value is set by said means for manually setting said diaphragm value provided in said camera body, and a second position, in which said diaphragm value is set by said means for manually setting said diaphragm value provided in said taking lens.

16. The exposure control apparatus of claim 14, wherein, when said exposure value is locked by said exposure value locking means and when said diaphragm value is varied by said means for manually setting said diaphragm value provided in said taking lens, said varying means varies said manually set shutter speed while maintaining said locked exposure value.

17. An exposure control apparatus of a camera, comprising:
means for manually setting a diaphragm value and a shutter speed in a manual setting mode of said camera, said diaphragm value and shutter speed being settable independently of a luminance of an object to be photographed with said camera exposure value storing means for storing a product of APEX
values of said manually set shutter speed and said manually set diaphragm value; and means for varying one of said diaphragm value and shutter speed when the other of said diaphragm value and shutter speed is varied by said manual setting means when the product of said APEX values is stored in said exposure value storing means, so as to make a product of said varied diaphragm value and shutter speed equal to said APEX values stored in said exposure value storing means.

18. An exposure control apparatus of a camera, comprising:
first means for manually setting a shutter speed in a manual setting mode;
second means for manually setting a diaphragm value in a manual setting mode, said diaphragm value and shutter speed being independently settable with respect to a luminance of an object to be photographed with said camera;

exposure value locking means for fixing an exposure value to a constant value in accordance with said manually set shutter speed and said manually set diaphragm value; and shutter speed varying means for varying, when said exposure value is fixed by said exposure value locking means, said shutter speed in accordance with said fixed exposure value when a diaphragm ring is rotated to vary said diaphragm value so as to maintain said exposure value to said constant value.

19. The exposure control apparatus of claim 18, wherein when said shutter speed is varied by a predetermined value, the diaphragm value is varied by an equal value.

20. The exposure control apparatus of claim 18, wherein when said diaphragm value is varied by a predetermined value, the shutter speed is varied by an equal value.

21. The exposure control apparatus of claim 18, wherein said exposure value locking means locks and unlocks said exposure value every time an associated lock switch is turned ON and OFF, respectively.

22. An exposure control apparatus for a camera, comprising:
means for manually inputting a shutter speed and a diaphragm value in a manual setting mode, said shutter speed and said diaphragm value being independently settable with respect to a luminance of an object to be photographed;
means for locking an exposure value calculated in accordance with said manually inputted shutter speed and manually inputted diaphragm value; and means for automatically varying one of said shutter speed and diaphragm value after said exposure value is set by said locking means when the other of said shutter speed and diaphragm value is manually changed so as to maintain constant said locked exposure value.

23. The exposure control apparatus of claim 22, wherein said manual inputting means for inputting said shutter speed is provided in a camera body of said camera, and said manual inputting means for inputting said diaphragm value is provided in a lens of said camera.

24. The exposure control apparatus of claim 22, wherein when said shutter speed is varied by a predetermined value, said locking means varies the diaphragm value by an equal value.

25. The exposure control apparatus of claim 22, wherein when said diaphragm value is varied by a predetermined value, said locking means varies the shutter speed by an equal value.