Abstract:
A camera includes a movable mirror which moves between a mirror-down position and a mirror-up position, an attitude detecting device which detects an attitude of the camera, and a control circuit in which a plurality of periods of stabilization time of the movable mirror are set and which changes over the stabilization time of the movable mirror among the plurality of periods according to a result of detection provided by the attitude detecting device. If the attitude of the camera has changed in process of a continuous photo-taking operation, the control circuit keeps the stabilization time of the movable mirror set at the time of start of the continuous photo-taking operation without changing over the stabilization time of the movable mirror.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a camera having an attitude detecting function and arranged to perform control according to the attitude of the camera. 
     2. Description of Related Art 
     FIG. 11 shows a single-lens reflex camera. The single-lens reflex camera is provided with a main mirror  104  for guiding an object image, i.e., information on an object to be photographed, from a photo-taking lens  103  to an eyepiece  107  and a light measuring sensor  108  through a viewfinder optical system  106 . The main mirror  104  is swingably disposed between the photo-taking lens  103  and a shutter  110  which is arranged to control an exposure amount in exposing a film  111  to the object image coming from the photo-taking lens  103 . When the camera measures light while the camera user is observing the object before taking a shot, the main mirror  104  is set at an observing position, i.e., at an entrance position within a photo-taking optical path where the object image from the photo-taking lens  103  can be guided to the eyepiece  107 . 
     A central part of the main mirror  104  is arranged to be a half mirror. A submirror  105  is swingably carried by the main mirror  104 . A part of the object information from the photo-taking lens  103  passes through the half mirror part of the main mirror  104  to be guided to a focus detecting device  112  through the submirror  105 . 
     To prevent the object image from the photo-taking lens  103  from being eclipsed by the main mirror  104  and the submirror  105  in taking a shot, the mirrors  104  and  105  are swung upward into a retracted position which is located outside of the photo-taking optical path. 
     After completion of an exposure, the main mirror  104  and the submirror  105  are moved back to the observing position to permit observation of the object and light-measuring and focus-detecting actions for the next shot. 
     The main mirror  104  is urged to move downward by a spring (not shown). When a member which is pushing the main mirror  104  upward is released from the pushing action after completion of an exposure, the main mirror  104  is caused by the urging force of the spring to swing downward back to the observing position. Following the downward motion of the main mirror  104 , the submirror  105  also moves back to the position shown in FIG.  11 . 
     According to the procedures for the sequence of actions of the camera to be performed after an exposure, the light-measuring and focus-detecting actions, etc., for the next shot are allowed to be performed after the lapse of a predetermined period of time (mirror stabilization time) from the commencement of downward movement of the mirrors  104  and  105  from the retracted position to the observing position. The predetermined period of mirror stabilization time is set at a length of time found through tests to be required after the commencement of the downward movement of the mirrors from the retracted position to the observing position and before they cease to bounce on stoppers to lay at rest. 
     However, since each of the mirrors has a certain amount of mass, the length of time to be set as the mirror stabilization time varies with the posture or attitude of the camera. In other words, the mirror stabilization time varies according to the relation of the urging direction of a spring force to the direction of gravity. In view of this, a camera disclosed, for example, in Japanese Laid-Open Patent Application No. HEI 6-74766 is arranged to have the mirror stabilization time selectable from among a plurality of periods set according to the various attitudes of the camera. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, there is provided a camera comprising a movable mirror which moves between a mirror-down position and a mirror-up position, an attitude detecting device which detects an attitude of the camera, and a control circuit in which a plurality of periods of stabilization time of the movable mirror are set and which changes over the stabilization time of the movable mirror among the plurality of periods according to a result of detection provided by the attitude detecting device, wherein, if the attitude of the camera has changed in process of a continuous photo-taking operation, the control circuit keeps the stabilization time of the movable mirror set at the time of start of the continuous photo-taking operation without changing over the stabilization time of the movable mirror, so that it is possible to continue the photo-taking operation at a fixed interval during process of the continuous photo-taking operation. 
     The above and other aspects and features of the invention will become apparent from the following detailed description of a preferred embodiment thereof taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIGS. 1A and 1B are sectional views showing the essential parts of a camera according to an embodiment of the invention. 
     FIGS. 2A,  2 B and  2 C are diagrams for explaining the movement of the mirror in the camera at different attitudes. 
     FIGS. 3A,  3 B and  3 C are diagrams showing the construction of each of attitude detecting switches in the camera. 
     FIGS. 4A and 4B are diagrams showing the construction of the attitude detecting switch in the camera. 
     FIGS. 5A,  5 B and  5 C are diagrams showing the allocations of the attitude detecting switches. 
     FIGS. 6A,  6 B,  6 C,  6 D,  6 E and  6 F are diagrams showing different attitudes of the camera. 
     FIGS. 7A and 7B are tables showing the relationships between the outputs of the attitude detecting switches and the various attitudes of the camera. 
     FIG. 8 is a timing chart showing a continuous photo-taking operation of the camera. 
     FIG. 9 is a block diagram showing the electrical circuit arrangement of the camera. 
     FIG. 10 is a flow chart showing actions of the camera to be performed during the continuous photo-taking operation. 
     FIG. 11 is a sectional view showing essential parts of a conventional camera. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a preferred embodiment of the invention will be described in detail with reference to the drawings. 
     FIGS. 1A and 1B and FIG. 5A show a single-lens reflex camera according to the embodiment of the invention. FIGS. 1A and 1B are sectional views of the camera, while FIG. 5A is a front view of the camera. 
     FIGS. 2A,  2 B and  2 C are diagrams for explaining the mirror-down action of the camera. 
     Referring to FIGS. 1A and 1B, reference numeral  1  denotes a camera body and reference numeral  2  denotes a lens barrel  2  holding a photo-taking lens  3 . A main mirror  4  is mounted on the camera body  1  in such a way as to be vertically swingable. A submirror  5  is swingably mounted on the main mirror  4 . A pentagonal roof prism  6  is arranged to constitute a viewfinder optical system. Reference numeral  7  denotes an eyepiece. A light measuring lens  9  is arranged to form an image on a light measuring sensor  8 . A shutter  10  is arranged to control the amount of exposure light to which a film  11  is to be exposed. The film  11  is a photosensitive material. A focus detecting device  12  is disposed at a lower part of the camera body  1 . 
     In FIG. 5A, reference numeral  17  denotes a release button. Reference numerals  20  to  23  denote attitude detecting switches arranged to detect the attitude of the camera body  1 . 
     In the camera body  1 , the main mirror  4  is arranged between the photo-taking lens  3  and the shutter  1  to be vertically swingable. When the user of the camera is observing an object to be photographed, the main mirror  4  is obliquely set at an observing position within the photo-taking optical path and acts to guide the object image from the photo-taking lens  3  to the viewfinder optical system in such a way as to enable the user to see an object image and also to permit a light measuring action by means of the light measuring sensor  8 . 
     A central part of the main mirror  4  is formed to be a half mirror. The submirror  5  is swingably mounted behind the half-mirror part of the main mirror  4 . Image information on the object obtained from the photo-taking lens  3  passes through the half-mirror part of the main mirror  4  to be reflected and guided by the submirror  5  to the focus detecting device  12 . 
     In taking a picture, to prevent the object image from the photo-taking lens  3  from being eclipsed by the main mirror  4  and the submirror  5 , the main mirror  4  is swung upward into a retracted position located outside of the photo-taking optical path. Then, the submirror  5  is swung in the direction of covering and closing the half-mirror part of the main mirror  4 . At the time of exposing the film  11  to light for photo-taking, this arrangement effectively prevents an apposite exposure action on the film  11  from being hindered by any light ingressing from the viewfinder optical system. After that, the exposure action is carried out on the film  11  by opening and closing the shutter  10 . 
     After completion of the exposure, to promptly permit observation of the object and light-measuring and focus-detecting actions for the next shot, the main mirror  4  and the submirror  5  are brought back to the observing position before photo-taking, in response to an exposure completion signal. 
     The main mirror  4  is urged to move downward (toward the observing position) by means of a spring (not shown). When a member which is pushing the main mirror  104  upward is released from the pushing action, the main mirror  104  is caused by an urging force of the spring to swing downward back to the observing position. Then, the submirror  105  is also caused by the urging force of the spring to swing in the direction of opening with respect to the main mirror  4  and thus comes back to its position shown in FIG.  1 A. 
     In the above sequence of actions of the camera, a period of time required after the exposure completion signal is outputted until the main mirror  4  is stably positioned in the observing position to permit light-measuring and focus-detecting actions, etc., for the next shot, i.e., the mirror stabilization time required after the main mirror  4  and the submirror  5  are driven by the spring to the observing position until the main mirror  4  and the submirror  5  cease to bounce to lay at rest, varies with the attitude of the camera. The reason for this is as follows. 
     Each of the main mirror  4  and the submirror  5  has a certain amount of mass, and the relation of the urging direction of the spring for driving the main mirror  4  and the submirror  5  to the direction of their dead weight (the direction of receiving the gravitational force) varies with the attitude of the camera. 
     Therefore, a length of time during which the mirrors  4  and  5  are driven and another length of time during which the the mirrors  4  and  5  bounce continues vary according to the attitude of the camera. 
     FIGS. 2A to  2 C show the movement of the main mirror  4  and the submirror  5  taking place after the exposure completion signal is outputted. FIG. 2A shows the movement of the mirrors  4  and  5  taking place with the camera in a normal attitude, in which the pentagonal roof prism  6  is facing upward. FIG. 2B shows the movement of the mirrors  4  and  5  taking place with the camera in a lens-down attitude, in which the photo-taking lens  3  is facing downward. FIG. 2C shows the movement of the mirrors  4  and  5  taking place with the camera in an inverted (upside-down) attitude, in which the pentagonal roof prism  6  is facing downward. 
     In each of the cases shown in FIGS. 2A to  2 C, after the main mirror  4  and the submirror  5  begin to be driven with the exposure completion signal outputted, the mirrors  4  and  5  collide against stoppers (not shown) disposed at the observing position, and then bounce some number of times on the stoppers before the mirrors  4  and  5  come to rest in the observing position. The mirror stabilization time, which is required after the output of the exposure completion signal until the mirrors  4  and  5  come to lay at rest in the observing position, was found, by tests, to be “ta”,“tb” or “tc”,as shown in FIG. 2A,  2 B or  2 C. 
     As apparent from FIGS. 2A to  2 C, the mirror stabilization time “tb” required with the camera in the lens-down attitude as shown in FIG. 2B is approximately equal to the mirror stabilization time “tc” required with the camera in the inverted attitude as shown in FIG. 2C, and is longer than the mirror stabilization time “ta” required with the camera in the normal attitude as shown in FIG.  2 A. 
     Further, in cases where the camera is in other attitudes, i.e., vertical attitudes shown in FIGS. 6E and 6F and a lens-up attitude in which the photo-taking lens  3  is facing upward as shown in FIG. 6C, the mirror stabilization time was found, by tests, to be about the same as the mirror stabilization time “ta” required with the camera in the normal attitude as shown in FIG.  2 A. 
     According to the embodiment of the invention, the attitudes of the camera are divided, on the basis of the above test data, etc., into an attitude-A group which requires a shorter period of mirror stabilization time (the normal attitude, the lens-up attitude and the vertical attitudes) and an attitude-B group which requires a longer period of mirror stabilization time (the inverted attitude and the lens-down attitude). Then, a continuous photo-taking operation is controlled while taking into consideration the attitude-A group and the attitude-B group, as will be further described later. 
     A method for detecting the attitude of the camera is next described below with reference to FIGS. 3A to  3 C to FIGS. 7A and 7B. 
     FIGS. 3A,  3 B and  3 C show the construction of each of the attitude detecting switches  20  to  23 , which are provided in the camera and have the same construction. FIG. 3A is a plan view showing the attitude detecting switch. FIG. 3B is a sectional view of the attitude detecting switch taken on a line C—C shown in FIG.  3 A. FIG. 3C is a sectional view of the attitude detecting switch taken on a line D—D shown in FIG.  3 A. 
     Referring to FIGS. 3B and 3C, a switch body  24  is formed with plastic. A groove part  24   a  is formed in the switch body  24 . A steel ball  25  is disposed in the groove part  24   a . The steel ball  25  is freely rollable within the groove part  24   a.    
     As shown in FIG. 3C, the groove part  24   a  has a width slightly wider than the diameter of the steel ball  25 , as viewed in the direction of the section D—D. As viewed on the section C—C, the groove part  24   a  is approximately in a V shape composed of first and second slanting surfaces  24   c  and  24   c  and a vertex part  24   b . A light projecting window  24   e  for a photodiode  26  and a light receiving window  24   f  for a phototransistor  27  are formed in the neighborhood of the vertex part  24   b  in such a way as to confront each other. The angle θ of the V shape of the groove part  24   a  is about 90 degrees. A lid  28  is fixed by bonding to the upper part of the switch body  24  to have the steel ball  25  sealed within the groove part  24   a.    
     For the sake of defining the directions taken by the attitude detecting switches  20  to  23 , the lower side surface of the switch body  24  as shown in FIG. 3B is assumed to be a surface A and a right side surface of the switch body  24  as shown in FIG. 3B is assumed to be a surface B. 
     Each of the attitude detecting switches  20  to  23  operates as described below with reference to FIGS. 4A and 4B. FIG. 4A shows the attitude detecting switch as in a state having the surface B downward. FIG. 4B shows the attitude detecting switch as in a state having the surface A downward. 
     When the attitude detecting switch is in the state shown in FIG. 4A, the steel ball  25  is caused by gravity to roll downward within the groove part  24   a . Therefore, in this state, the optical path between the light projecting window  24   e  and the light receiving window  24   f  is never blocked by the steel ball  25 . 
     When the attitude detecting switch is in the state shown in FIG. 4B, the steel ball  25  is caused by gravity to roll down within the groove part  24   a  toward the vertex part  24   b . Therefore, in that state, the optical path between the light projecting window  24   e  and the light receiving window  24   f  is blocked by the steel ball  25 . 
     Generally, when the vertex part  24   b  is located at the lowest position within the groove part  24   a , the steel ball  25  rolls to a part near to the vertex part  24   b  to block the optical path between the light projecting window  24   e  and the light receiving window  24   f.    
     In the description of the present embodiment given hereinafter, the state in which the steel ball  25  is located near the vertex part  24   b  to block the optical path between the photodiode  26  and the phototransistor  27  as shown in FIG. 4B will be called a state “1”. The state in which the steel ball  25  is not located in the neighborhood of the vertex part  24   b  and thus the optical path between the photodiode  26  and the phototransistor  27  is left unblocked will be called a state “0”. 
     The photodiode  26  and the phototransistor  27  which are disposed within the attitude detecting switch are arranged to be driven by an attitude-detecting-switch driving circuit (not shown). A microcomputer which will be described later herein is arranged to detect the output of the phototransistor  27  by controlling the attitude-detecting-switch driving circuit. The state of each attitude detecting switch is thus judged by the microcomputer to be in the state “1” or in the state “0” according to the detection output thus obtained. 
     In actuality, the steel ball  25  has some rolling resistance. Therefore, in cases where the first slant surface  24   c  is located lower than the second slant surface  24   c  and is approximately horizontal, or where the second slant surface  24   c  is located lower than the first slant surface  24   c  and is approximately horizontal, or where both the first and second slant surfaces  24   c  and  24   c  are approximately horizontal, the steel ball  25  is not always located in the neighborhood of the vertex part  24   b . In other words, the attitude detecting switch then cannot be definitely found to be in the state “0” or in the state “1”. Such a state hereinafter will be called an unstable state. 
     The allocation of the attitude detecting switches  20  to  23  with respect to the camera body  1  is next described as follows. FIG. 5A is a front view of the camera showing the allocation of the attitude detecting switches  20  to  23 . FIGS. 5B and 5C are enlarged views respectively showing parts E and F of FIG.  5 A. 
     As shown in FIG. 5A, which is a front view of the camera, the first and second attitude detecting switches  20  and  21  are allocated at a lower left part of a photo-taking optical axis and below a shutter driving mechanism (not shown). Further, as viewed from the front side of the camera body  1 , the third and fourth attitude detecting switches  22  and  23  are allocated at an upper right part of the photo-taking optical axis and above a film cartridge chamber (not shown). 
     The first attitude detecting switch  20  is in a position, as viewed from the front of the camera, where its surface A is facing the left side of the camera and its surface B is facing the lower side of the camera. 
     The second attitude detecting switch  21  is in a position, as viewed from the front of the camera, where its surface A is facing the right side of the camera and its surface B is facing the lower side of the camera. 
     The third attitude detecting switch  22  is in a position where its surface A is facing the lower side of the camera and its surface B is facing the front side of the camera. 
     The fourth attitude detecting switch  23  is in a position where its surface A is facing the front side of the camera and its surface B is facing the right side of the camera, as viewed from the front side of the camera. 
     The states of each of the attitude detecting switches  20  to  23  for various attitudes of the camera are next described with reference to FIGS. 6A to  6 F. FIG. 6A shows the camera as in the normal attitude. FIG. 6B shows the camera as in the inverted (upside-down) attitude. FIG. 6C shows the camera as in the lens-up attitude. FIG. 6D shows the camera as in the lens-down attitude. FIG. 6E shows the camera as in a grip-up attitude, in which the camera is in a vertical attitude having its grip part located uppermost. FIG. 6F shows the camera as in a grip-down attitude, in which the camera is in another vertical attitude having its grip part located lowermost. 
     When the camera is in the normal attitudes as shown in FIG. 6A, the first attitude detecting switch  20  is in the state “0”,the second attitude detecting switch  21  in the state “0” and the third attitude detecting switch  22  in the state “1”. In this case, the fourth attitude detecting switch  23  is in the unstable state, as both the first slant surface  24   c  and the second slant surface  24   c  within the fourth attitude detecting switch  23  are approximately horizontal to make the position of the steel ball  25  unstable. 
     When the camera is in the inverted (upside-down) attitude as shown in FIG. 6B, the first attitude detecting switch  20  is in the state “0”, the second attitude detecting switch  21  in the state “0” and the third attitude detecting switch  22  also in the state “0”, while the fourth attitude detecting switch  23  takes the unstable state. 
     When the camera is in the lens-up attitude as shown in FIG. 6C, the first attitude detecting switch  20  and the second attitude detecting switch  21  take the unstable state, while the third attitude detecting switch  22  is in the state “0” and the fourth attitude detecting switch  23  is also in the state “0”. 
     When the camera is in the lens-down attitude as shown in FIG. 6D, both the first attitude detecting switch  20  and the second attitude detecting switch  21  take the unstable state, while the third attitude detecting switch  22  is in the sate “0” and the fourth attitude detecting switch  23  in the state “1”. 
     When the camera is in the grip-up (vertical) attitude as shown in FIG. 6E, the first attitude detecting switch  20  is in the state “0”,the second attitude detecting switch  21  is in the state “1”,the third attitude detecting switch  22  is in the unstable state, and the fourth attitude detecting switch  23  in the state “0”. 
     When the camera is in the grip-down (vertical) attitude as shown in FIG. 6F, the first attitude detecting switch  20  is in the state “1”,the second attitude detecting switch  21  is in the state “0”,the third attitude detecting switch  22  is in the unstable state, and the fourth attitude detecting switch  23  is in the state “0”. 
     FIG. 7A is a table showing the above-stated attitudes of the camera in relation to the states of the attitude detecting switches mentioned above. While the states of the four attitude detecting switches, i.e., the first to fourth attitude detecting switches  20  to  23 , have  16  conceivable combinations, the table of FIG. 7A includes only  12  combinations of the states of the switches. 
     The four combinations of the states of the attitude detecting switches which are excluded from the table of FIG. 7A are as follows. (1) A case where the states of the attitude detecting switches  20  to  23  are, serially from the first attitude detecting switch  20 , in a combination of “1”, “1”, “1” and “0”: It is possible to have the first and second attitude detecting switches  20  and  21  both in the state “1” only when the camera is in the lens-up or lens-down attitude. However, with the camera in each of the two attitudes, the third attitude detecting switch  22  necessarily takes the state “0” without fail. In other words, this combination is normally impossible and is conceivable only when there is some abnormality in respect to the attitude detecting switches, the attitude-detecting-switch driving circuit, etc. 
     (2) A case where the states of the attitude detecting switches  20  to  23  are, serially from the first attitude detecting switch  20 , in a combination of “1”, “0”, “1” and “1”: This combination is conceivable when the attitude of the camera is between the normal attitude, the lens-down attitude and the grip-down vertical attitude. In this case, the first slant surface  24   c  in the first attitude detecting switch  20 , the first slant surface  24   c  in the third attitude detecting switch  22  and the second slant surface  24   c  in the fourth attitude detecting switch  23  all become approximately horizontal to have the respective steel balls  25  in the unstable state. 
     (3) A case where the states of the attitude detecting switches  20  to  23  are, serially from the first attitude detecting switch  20 , in a combination of “0”, “1”,“1” and “1”: this combination is conceivable when the camera is between the normal attitude, the lens-down attitude and the grip-up vertical attitude. In that case, the first slant surface  24   c  in the second attitude detecting switch  21 , the first slant surface  24   c  in the third attitude detecting switch  22 , the first slant surface  24   c  in the fourth attitude detecting switch  23  all become approximately horizontal to have the respective steel balls  25  in the unstable state. 
     (4) A case where the states of the attitude detecting switches  20  to  23  are, serially from the first attitude detecting switch  20 , in a combination of “1”, “1”, “1” and “1”: This combination is normally impossible for the same reason as in the case of the above-stated combination (1). The combination (4) is conceivable only when the attitude detecting switches or the attitude-detecting-switch driving circuit is in an abnormal state. 
     FIG. 7B is a table recapitulating the correlation of combinations of states of the attitude detecting switches and the attitudes of the camera as shown in FIG.  7 A and described above. 
     FIG. 9 shows the electrical circuit arrangement of the camera according to the embodiment of the invention. In FIG. 9, reference numeral  80  denotes a central processing unit (hereinafter referred to as the CPU). Reference numerals  90  to  95  denote driving circuits arranged for control over motors, a magnet, etc., according to signals from the CPU  80 . 
     Referring to FIG. 9, a motor  1  ( 81 ) is a charge motor serving as a drive source for a charging action on the shutter, etc. A motor  2  ( 82 ) is a film transport motor serving as a drive source for film transport. 
     A clamping magnet  83  is arranged to lock a lever (not shown) which is arranged to resiliently raise the main mirror  4 , when a coil of the clamping magnet  83  is not energized, and to unlock the lever when the coil is energized. 
     A lens driving mechanism  55  is arranged to drive the photo-taking lens  3  in the direction of an optical axis with a built-in motor (not shown). A diaphragm driving mechanism  56  is arranged to drive a diaphragm (not shown) disposed within the photo-taking lens  3  to open and close the diaphragm with a built-in motor (not shown). 
     A switch A ( 51 ) is arranged to cause various detecting actions, such as light-measuring and focus-detecting actions, to begin by turning on when the release button  17  is pushed halfway. A switch B ( 52 ) is arranged to cause a shutter opening-and-closing action, i.e., a photo-taking action, to begin by turning on when the release button  17  is pushed to a full extent. 
     A light measuring circuit  53  is arranged to measure the light of an object of shooting on the basis of the output of the light measuring sensor  8 . A focus detecting circuit  54  is arranged to detect the state of focus for a predetermined focus detecting area on the basis of the output of a CCD or the like arranged within the focus detecting device  12 . 
     A mirror-up switch  57  is arranged to detect completion of an action of driving the main mirror  4  from the observing position to the retracted position. 
     An exposure completion signal generating circuit  59  is arranged to output an exposure completion signal indicating that an exposure action on the film  11  has finished by opening and closing the shutter  10 . A charge signal generating circuit  60  is arranged to output a charge signal which indicates completion of a charging action on the shutter  10  to be performed before the shutter operating action. A film transport signal generating circuit  61  is arranged to output a film transport signal indicating that one frame portion of the film  11  has been wound up after completion of an exposure action on the frame. 
     A continuous shooting (photo-taking) operation of the camera is next described with reference to FIG. 10, which is a flow chart, and FIG. 8, which is a timing chart. 
     At a step ST 1  shown in FIG. 10, when the power supply (not shown) of the camera is turned on, a counter arranged to count the number of photo-taking frames used for continuous shooting is set at “0” as initial setting. At a step ST 2 , a check is made to find if the switch A ( 51 ) is tuned on with the release button  17  pushed halfway. If so, the flow of operation proceeds to a step ST 3 . At the step ST 3 , upon detection of the on-state of the switch A ( 51 ), the CPU  80  causes the light measuring circuit  53  to start operating and performs a light measuring arithmetic operation on the output of the light measuring circuit  53 . At a step ST 4 , at the same time, the focus detecting circuit  54  is also caused to start operating and a focus detecting arithmetic operation is performed on the output of the focus detecting circuit  54 . At a step ST 5 , the driving circuit  94  and the lens driving mechanism  55  are caused to drive the photo-taking lens  3  to carry out focus adjustment. 
     At a step ST 6 , a check is made to find if the switch B ( 52 ) is turned on with the release button  17  pushed fully. If so, the flow proceeds to a step ST 7 . At the step ST 7 , upon detection of the on-state of the switch B ( 52 ), the CPU  80  makes a check for a signal from the charge signal generating circuit  60  indicating completion of charging. At a step ST 8 , the coil of the clamping magnet  83  is energized to unlock the lever (not shown) and to cause the main mirror  4  to spring up into the retracted position by the lever. At a step ST 9 , at the same time, the diaphragm driving mechanism  56  is caused through the driving circuit  95  to stop the diaphragm of the photo-taking lens  3  down to a predetermined aperture position. 
     At a step ST 10 , a check is made to find if the mirror-up switch  57  has been turned on by the completion of driving the main mirror  4  to the retracted position. If so, the flow proceeds to a step ST 11 . At the step ST 11 , a check is made for a signal from the film transport signal generating circuit  61  to find if a film transport action has finished. If so, the flow proceeds to a step ST 12 . At the step ST 12 , upon completion of the diaphragm and lens driving actions, the shutter  10  is operated to carry out a film exposure by operating the shutter  10 . 
     At a step ST 13 , a check is made for an exposure completion signal from the exposure completion signal generating circuit  59  to find if the exposure has been finished by operating the shutter  10 . If so, the flow proceeds to steps ST 14 , ST 15 , ST 16 , ST 17  and ST 18  at the same time. At the step ST 14 , the CPU  80  causes, through the driving circuit  90 , the motor  1  ( 81 ) to charge the shutter  10 , etc. At the step ST 15 , the motor  2  ( 82 ) is caused through the driving circuit  91  to carry out a one-frame winding action on the film  11 . At the step ST 16 , the member (not shown) which has been pushing the main mirror  4  up to the retracted position is freed to allow the main mirror  4  to begin to move to the observing position. At the step ST 17 , the diaphragm (not shown) is returned to the open position. Further, in order to find the lapse of mirror stabilization time from the time point at which the exposure completion signal is outputted, a mirror stabilization timer which is arranged to count the mirror stabilization time is caused to start counting. 
     At the step ST 18 , the continuous shooting counter is also caused, at the same time, to perform upward counting. As a result, the count value of the continuous shooting counter becomes “1” upon completion of the exposure action on the first frame of the continuous shooting (photo-taking) operation. 
     At the next step ST 19 , a check is made to find if the count value of the continuous shooting counter is at “1”. If so, that is, upon completion of the first shot of the continuous shooting, the flow proceeds to a step ST 20 . At the step ST 20 , a check is made to find if the attitude of the camera belongs to the above-stated attitude-A group or the attitude-B group, on the basis of the above-stated combinations of the outputs of the attitude detecting switches  20  to  23 . 
     If the attitude of the camera is found to belong to the attitude-A group, the flow proceeds to a step ST 21  to set the mirror stabilization timer at “T1” which is  50  ms. If the attitude of the camera is found to belong to the attitude-B group, the flow proceeds to a step ST 22  to set the mirror stabilization timer at “T2” which is  80  ms. 
     At a step ST 23 , a check is made for the lapse of the mirror stabilization time as counted by the mirror stabilization timer. After the lapse of the mirror stabilization time, the flow returns to the step ST 2  to find if the switch A ( 51 ) continues to be in its on-state. If so, the flow proceeds to the steps ST 3  and ST 4  to cause the light measuring circuit  53  and the focus detecting circuit  54  to start their actions for the second shot (frame) of the continuous shooting. Then, the light measuring and focus detecting arithmetic operations are carried out. At the step ST 5 , the lens is driven for focus adjustment on the basis of the result of the focus detecting arithmetic operation. Further, if the switch B ( 52 ) is found at the step ST 6  to be still in its on-state, the flow proceeds to the step ST 7  to make a check for the signal from the charge signal generating circuit  60  to find if charging has been finished. If so, the flow proceeds to the steps ST 8  and ST 9  to drive the main mirror  4  to the retracted position and, at the same time, to stop the diaphragm of the lens down to a predetermined aperture position. The flow then proceeds to the step ST 10  to find completion of the process of driving the main mirror  4  to the retracted position, and to the step ST 11  to find completion of the process of winding one frame of the film  11 . At the step ST 12 , the shutter  10  is caused to be operated (opened and closed) after completion of diaphragm and lens driving processes. Accordingly, an exposure is carried out for the second shot of the continuous shooting. 
     When the exposure completion signal is found at the step ST 13  to have been outputted after completion of the shutter operation, the CPU  80  causes the motor  1  ( 81 ) to be actuated to charge the shutter, etc., at the step ST 14  and also causes the motor  2  ( 82 ) to be actuated to perform the one-frame winding action on the film  11  at the step ST 15 . 
     At the same time, the member pushing up the main mirror  4  to the retracted position is freed to have the main mirror  4  moved to the observing position at the step ST 16 , and the aperture position of the lens diaphragm is caused to come back to its full open position at the step ST 17 . Then, the mirror stabilization timer which is provided for detecting the lapse of mirror stabilization time from the time point at which the exposure completion signal is outputted is caused to begin counting. 
     Further, the count value of the continuous shooting counter is incremented at the step ST 18 , and a check is made at the step ST 19  to find if the count by the continuous shooting counter is at “1”. 
     If the count value of the continuous shooting counter is found not “1”, that is, if the continuous shooting is made for the second frame (shot) or more, the flow of operation proceeds from the step ST 19  to a step ST 24 . At the step ST 24 , a check is made for the setting value of the mirror stabilization timer set for the shot of the preceding frame. If the setting value of the mirror stabilization timer is found to be the value T2, no attitude detecting action is performed, and the setting value of the mirror stabilization timer is kept as it is. The flow then proceeds from the step ST 24  to the step ST 23 . Then, after the lapse of the setting value of the mirror stabilization timer, the flow returns to the step ST 2  to make the check for the state of the switch A ( 51 ) and to repeat the same steps for the continuous shooting operation. 
     Further, if the mirror stabilization timer is found at the step ST 24  to be set at the value T1, the flow proceeds to a step ST 25  to detect the attitude of the camera in the same manner as the step ST 20 . If the attitude of the camera is found to belong to the attitude-A group, the flow proceeds to a step ST 26 . At the step ST 26 , the mirror stabilization timer is left at the setting value T1, and the flow proceeds from the step ST 26  to the step ST 23 . If the attitude of the camera is found at the step ST 25  to have changed to the attitude-B group, the flow proceeds from the step ST 25  to a step ST 27 . At the step ST 27 , the setting value of the mirror stabilization timer is changed to a setting value T3 (0 ms). The flow then proceeds from the step ST 27  to the step ST 6  to make the check for the state of the switch B ( 52 ), without performing the light measuring action and the focus detecting action. If the switch A ( 51 ) and the switch B ( 52 ) are found to still remain in their on-states, the continuous shooting operation is further performed on frames one after another by using, as exposure data, the results of light-measuring and focus-detecting arithmetic operations for the exposure of the first frame for the exposure of the second and subsequent frames. 
     However, if the attitude of the camera comes to be found at the step ST 25  to have changed back to the attitude-A group while the continuous shooting is carried on using the setting value T3 of the mirror stabilization timer, the flow proceeds to the step ST 26  to set the mirror stabilization timer at the value T1again for further carrying on the continuous shooting operation. 
     If the switch B ( 52 ) is turned off, the continuous shooting operation is considered to have been suspended, and the flow returns to the step ST 1  to set the continuous shooting counter at the initial setting value “0”. When the switches A ( 51 ) and B ( 52 ) are again turned on, continuous shooting is performed from the shot of the first frame. 
     As described above, according to the embodiment of the invention, with the attitude of the camera found to belong to the attitude-A group (for example, the normal attitude) in taking a shot for the first fame of continuous shooting, if the attitude of the camera has changed to the attitude-B group (for example, the lens-down attitude) in process of the continuous shooting, the setting value of the mirror stabilization timer is changed from the value T1 to the value T3, and the continuous shooting is continued on the basis of the measured light value and the focus position used in taking a shot for the preceding frame without performing the light-measuring and focus-detecting actions. Then, if the attitude of the camera has again come back to the attitude-A group, the value of the mirror stabilization timer is changed from the setting value T3 to the value T1. In this instance, the light-measuring and focus-detecting actions are performed and a shot is taken for the next frame on the basis of the results of these actions. As apparent from the timing chart of FIG. 8, the length of time required for the light-measuring and focus-detecting actions is extremely short. Therefore, there is not much difference in frame feeding speed between the shot taken by performing the light-measuring and focus-detecting actions and the shot taken without these actions. In other words, in this instance, the high-speed continuous shooting operation can be carried out at a constant interval between shots despite of the change in attitude of the camera. 
     Further, with the attitude of the camera found to belong to the attitude-B group in taking a shot for the first fame of continuous shooting, if the attitude of the camera has changed to the attitude-A group in process of the continuous shooting, the light-measuring and focus detecting actions are carried out while keeping the setting value of the mirror stabilization timer at the value T2 as it is, and the continuous shooting is carried on the basis of the results of these actions. Further, in that instance, no attitude detecting action is performed thereafter. Therefore, although the frame feeding speed of the continuous shooting is slower by 30 ms than in the case of the high-speed continuous shooting operation, the continuous shooting can be steadily carried on at a constant speed. 
     According to the arrangement of the embodiment as described above, when the attitude of the camera has changed in process of continuous shooting, the frame feeding speed of the continuous shooting is stabilized according to the attitude of the camera in which the first shot of the continuous shooting has been taken, so that the frame feeding speed can be prevented from unexpectedly changing. The arrangement thus effectively prevents intervals between shots from varying with the attitude of the camera to give a disagreeable feeling to the operator of the camera.