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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a camera capable of slow synchro
photographing in a camera usable together with a flash apparatus. The slow
synchro herein implies a photographing method possible of finely
photographing not only a principal subject but also a background night
scene by expanding a control range of a shutter speed up to a slow speed
time of second.
The present invention is directed, more particularly, to a camera capable
of slow synchro in which a flash timing of a built-in or mounted flash
apparatus and a shutter speed are controlled.
The present invention is directed, still more particularly, to a camera
mountable with a flash apparatus possible of setting a leading curtain
synchro mode and a trailing curtain synchro mode.
2. Related Background Art
NIKON F-801 is known as a conventional camera capable of photographing in
any one of a shutter speed auto setting exposure mode for automatically
setting a shutter speed in accordance with a luminance value of a subject
and a shutter speed manual setting exposure mode for setting the shutter
speed to a manually set value in the case of photographing by use of a
flash apparatus.
A specific flash apparatus is mounted in this camera, and the shutter speed
auto setting mode is set. In this case, a restriction of a hand deflection
camera-shake limit shutter speed works. This hand deflection limit shutter
speed restriction is intended to prevent a photographing failure due to a
hand deflection by restricting the shutter speed from being set to a value
slower than a hand deflection limit shutter speed (which is the lowest
shutter speed within a shutter speed range enough not to cause a
photographing failure due to the hand deflection, e.g., 1/60 sec in the
case of the same camera). This speed restriction is arranged not to
function in the shutter speed manual setting mode.
One of the specific flash apparatuses mounted in F-801 is NIKON speed light
SB-24. This flash apparatus has a synchro mode changeover member for
determining whether the slow synchro is set or not. This synchro mode
changeover member is movable between a synchro mode setting position and a
normal synchro mode setting position. A position of the synchro mode
changeover member makes it possible to know which synchro mode to set.
Where this slow synchro mode is set in the shutter speed auto setting
exposure mode, F-801 photographs finely not only the principal subject but
also the background night scene thereof. It is therefore feasible to
control the shutter at a speed slower than the hand deflection limit
shutter speed in accordance with a subject luminance by releasing the
restriction of the hand deflection limit shutter speed.
In a combination of NIKON F-801 with NIKON speed light SB-24, however, the
synchro mode changeover member is movable to the normal and slow synchro
mode setting positions even in the shutter speed manual setting exposure
mode. Hence, there exists a possibility in which the user misunderstands
that there are, as in the case of shutter speed auto setting exposure
mode, the normal synchro mode to apply the hand deflection restriction
when setting the shutter speed and the slow synchro mode to release the
restriction even in the shutter speed manual setting exposure mode.
In this type of conventional cameras, some are capable of
switchover-setting a so-called trailing curtain synchro mode for
permitting the flash apparatus to emit the light just before shutter
trailing curtain running and a so-called leading curtain synchro mode for
permitting the flash apparatus to emit the light immediately after shutter
leading curtain running.
In the conventional cameras, however, the normal synchro mode is
automatically selected during a leading curtain synchro mode selection.
The slow synchro mode is automatically selected during a trailing curtain
synchro mode selection.
The normal synchro mode is herein defined as a synchro mode in which a
shutter speed is set within a range from a synchronizing shutter speed of
the flash apparatus to a hand deflection limit shutter speed. The slow
synchro mode is defined as a synchro mode in which the shutter speed is
set within a range from the synchronizing shutter speed of the flash
apparatus to a speed slower than the hand deflection limit shutter speed.
It is impossible to select a combination of the leading curtain synchro
mode with the slow synchro mode.
If the leading curtain synchro mode is set in the slow synchro mode, a
shutter opening time is controlled within a normal shutter control range
lower limit. The principal subject is grasped by a flash immediately after
a completion of leading curtain running by a release. An expression of the
principal subject can be grasped well. If the principal subject is dark,
the opening time is controlled under a time of second enough not to cause
the hand defection. Where the camera is fixed by a tripod or the like so
as not to produce the hand deflection, it is possible to take a photo
which sufficiently takes in a flash light source of the flash apparatus 20
and the background light as well. Under such circumstances, there is
increasingly a demand for making selectable the combination of the leading
curtain synchro mode with the slow synchro mode.
On the other hand, however, if the leading curtain synchro mode/trailing
curtain synchro mode and the normal synchro mode/slow synchro mode are
independently selectable, a combination of the trailing curtain synchro
mode with the normal synchro mode is produced.
Namely, the following is the reason why the trailing curtain synchro mode
is effective. Attained is photographing with a natural atmosphere where
the light appears to flow behind the principal subject by photographing
the principal subject with a flash of the flash apparatus at a proper
exposure when closing the trailing curtain while catching a light trace of
the moving subject at a slow speed time of second.
Hence, the trailing curtain synchro mode becomes effective in the case of
the slow synchro mode in which photographing is performed at the slow
speed time of second. If restricted in terms of the hand deflection time
of second when the normal synchro mode is set, the effect of the trailing
curtain synchro mode can not be obtained.
During the slow synchro mode, however, if the trailing curtain synchro mode
always comes, this may be inconvenient in some cases. For instance, when
taking a photo of a person with a background of night scene, an expression
of the person is captured more easily in the leading curtain synchro mode.
Furthermore, in some of the conventional flash apparatuses, the flash
apparatus itself has a changeover member capable of changing over the
trailing curtain synchro mode and the leading curtain synchro mode.
In the conventional devices, however, the trailing curtain synchro mode is
settable only when a special flash apparatus is mounted therein.
Considering a large-sized special flash apparatus or contrastingly a
small-sized flash apparatus, it is better to provide a set device in the
camera body.
Where the synchro mode set member is provided in the camera body, it
follows that the synchro mode set members are provided in both of the
flash apparatus and the camera body. A confusion may be induced when
setting the synchro mode.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a camera capable
of preventing the user from misunderstanding that there are a normal
synchro mode where a hand deflection restriction is applied to setting of
a shutter speed even in a shutter speed manual setting exposure mode and a
slow synchro mode where the restriction is released during slow synchro
photographing.
A construction of the present invention to accomplish the above-mentioned
object will be explained as follows, with the components marked with
symbols used in the embodiments which will be discussed later.
Provided according to an embodiment is an indication controller (SW1, SW2,
SW3, 10) for controlling an indicator for effecting a slow synchro
indication for showing that a slow synchro mode is set. During a shutter
speed auto setting mode, when applying a changeover operation to a synchro
mode changeover device for changing over a normal synchro mode and a slow
synchro mode, the indication controller permits the indicator to give the
slow synchro indication. During a shutter speed manual setting mode, no
slow synchro indication is given even when the changeover operation to the
slow synchro mode is applied to the synchro mode changeover device.
According to this embodiment, if an exposure control mode is the shutter
speed auto setting mode, the indication controller acts to give the slow
synchro indication when moving the synchro mode set member to a slow
synchro mode setting position. If the exposure control mode is the shutter
speed manual setting mode, the indication controller acts to give no slow
synchro indication even when moving the synchro mode set member to the
slow synchro setting position. If the user tries to set the slow synchro
mode during the shutter speed manual setting mode in which there is not
originally any restriction in shutter speed, the user does not
misunderstand because of no slow synchro indication being given.
Provided according to another embodiment is a synchro mode controller (SW1,
SW2, 10) for controlling an operation of a synchro mode changeover device.
The synchro mode controller permits a changeover to the slow synchro mode
in accordance with a manipulation to the synchro mode changeover device
during the shutter speed auto setting mode. The synchro mode controller
inhibits the changeover to the slow synchro mode in accordance with the
manipulation to the synchro mode changeover device.
According to this embodiment, the synchro mode controller permits the
changeover to the slow synchro mode in accordance with the manipulation to
the synchro mode changeover device during the shutter speed auto setting
mode. During the shutter speed manual setting mode, the synchro mode
controller inhibits the changeover to the slow synchro mode in accordance
with the manipulation to the synchro mode changeover device. A meaningless
changeover to the synchro mode is also thereby inhibited. It is therefore
possible to make invalid the manipulation to the synchro mode changeover
device more surely.
According to still another embodiment, a synchro mode controller (10, SW1,
SW2) is provided. When the shutter speed setting mode changeover device
performs a changeover from the shutter speed auto setting mode to the
shutter speed manual setting mode during a slow synchro mode setting
operation, a changeover from the slow synchro mode to the normal synchro
mode is automatically effected interlocking therewith.
According to this embodiment, the synchro mode controller causes the
shutter speed setting mode changeover device to perform the changeover
from the shutter speed auto setting mode to the shutter speed manual
setting mode during the slow synchro mode setting operation. The
changeover from the slow synchro mode to the normal synchro mode is then
carried out interlocking therewith. The normal synchro mode invariably
comes when performing the changeover from the shutter speed auto setting
mode to the shutter speed manual setting mode. This improves the
operability.
According to a further embodiment, a warning indicator (SW1, SW3, 14, 10)
is provided. If the exposure control mode is the shutter speed manual
setting mode, and when the synchro mode changeover device is operated, a
warning indication is given.
According to this embodiment, if the exposure control mode is the shutter
speed manual setting mode, and when the synchro mode changeover device is
operated, the warning indication is given. It is therefore possible for
the user to recognize that an insignificant operation is being carried
out.
It is another object of the present invention to provide a camera capable
of slow synchro in which a trailing curtain synchro mode is selected only
during a synchro mode (slow synchro mode) with no restriction of a slow
speed time of second to make photographing effective.
To accomplish the foregoing object, in a camera incorporating or mountable
with a flash apparatus 20, a camera possible of slow synchro according to
the present invention comprises: a first set device for setting any one of
a first synchro mode for setting a shutter speed in a range from a
synchronizing time of second of the flash apparatus 20 to a hand
deflection limit time of second, i.e., the synchro mode (normal synchro
mode) with a restriction of the slow speed time of second and a second
synchro mode for setting the shutter speed in a range from the
synchronizing time of second to a time of second slower than the hand
deflection limit time of second, viz., the synchro mode (slow synchro
mode) with no restriction of the slow speed time of second; a second set
device for setting any one of a leading curtain synchro mode for emitting
the light of the flash apparatus immediately after a completion of shutter
leading curtain running and a trailing curtain synchro mode for emitting
the light of the flash apparatus just before shutter trailing curtain
running; and an inhibition device for inhibiting simultaneous setting of
the synchro mode (normal synchro mode) with the restriction of the slow
speed time of second and the trailing curtain synchro mode.
Constructed also is the camera capable of slow synchro, wherein when the
trailing curtain synchro mode is set, the synchro mode with no restriction
of the slow speed time of second is automatically set.
Based on the above-described construction, the synchro mode (slow synchro
mode) with no restriction of the slow speed time of second can be combined
with the leading curtain synchro mode.
Inhibited is a combination of the (normal) synchro mode with the
restriction of the slow speed time of second with the trailing curtain
synchro mode.
When the trailing curtain synchro mode is set, the synchro mode (slow
synchro mode) with no restriction of the slow speed time of second is
automatically set.
It is still another object of the present invention to provide a camera
capable of preventing a confusion caused in setting of the synchro mode by
giving a priority to the synchro mode set by the flash apparatus in such a
case that each of the camera and the flash apparatus has a set device for
setting any one of the leading curtain synchro mode and the trailing
curtain synchro mode.
To accomplish the above-mentioned object, in a camera mountable with a
flash apparatus including a set device for setting any one of a leading
curtain synchro mode for emitting the light immediately after a completion
of shutter leading curtain running and a trailing curtain synchro mode for
emitting the light just after a start of shutter trailing curtain running,
a camera capable of setting the synchro mode according to this invention
comprises: a set device for setting any one of the leading curtain synchro
mode and the trailing curtain synchro mode; and a detection device for
detecting mounting or non-mounting of the flash apparatus and also
detecting which synchro mode to set in the flash apparatus when the flash
apparatus is mounted, the camera functioning in accordance with the
synchro mode exclusively set in the flash apparatus.
Based on the above-described construction, if the flash apparatus including
the set device is not mounted, the set member provided on the side of the
camera sets any one of the leading curtain synchro mode and the trailing
curtain synchro mode.
If the flash apparatus including the set device for the synchro mode is
mounted, the priority is given to the synchro mode set on the side of the
flash apparatus in advance of the synchro mode set on the side of the
camera.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent during
the following discussion taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a flowchart of a main routine of a MCU 10;
FIG. 3 is a flowchart of a timer interrupt processing routine;
FIG. 4 is a flowchart of a subroutine associated with setting of a synchro
mode in one embodiment;
FIG. 5 is a flowchart of an indication routine which is a part of the
indication routine and associated with the slow synchro;
FIGS. 6A-6C, 7A and 7B are diagrams illustrating indications associated
with the slow synchro of a camera of this invention;
FIG. 8 is a flowchart of a subroutine associated with setting of the
synchro mode in a first variant embodiment;
FIG. 9 is a flowchart of a subroutine associated with setting of the
synchro mode in a second variant embodiment;
FIG. 10 is a flowchart of a variant indication routine which is a part of
the indication routine and associated with the slow synchro;
FIG. 11 is a flowchart of a subroutine associated with setting of the
synchro mode in a third variant embodiment;
FIG. 12 is a flowchart of a subroutine associated with setting of the
synchro mode in another embodiment;
FIG. 13 is a diagram showing state transition of the synchro mode;
FIGS. 14(a) to (f) througth 16(a) to (f) are timing charts showing timings
during shutter control;
FIG. 17 is a flowchart of a main routine of the MCU 10;
FIG. 18 is a flowchart of a subroutine associated with setting of the
synchro mode;
FIGS. 19A-19C are diagrams illustrating state transitions of the synchro
mode;
FIG. 20 is a flowchart of a subroutine associated with indication of the
synchro mode; and
FIGS. 21A-21D are diagrams showing examples of indication.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a block diagram showing one embodiment of the present invention.
An EEPROM built-in microcomputer 10 is capable of holding the data stored
therein even when applying no power supply. This is hereinafter referred
to as an MCU (microcomputer unit). A light adjuster 11 connected to the
MCU 10 controls the light emitted from a flash apparatus 20. A light meter
12 connected to the MCU 10 measures a brightness of a subject through a
lens and outputs a subject luminance value. A set device 13 connected to
the MCU 10 sets a variety of parameters such as a film sensitivity and
others within the MCU 10. An indicator 14 connected to the MCU 10
indicate-outputs respective set values and control values. A diaphragm
controller 15 connected to the MCU 10 controls a diaphragm according to a
diaphragm value obtained in the MCU 10. A shutter controller 16 connected
to the MCU 10 controls a shutter at a shutter speed obtained in the MCU
10. A motor controller 17 connected to the MCU 10 performs sequence
control and feeds a film.
Based on the luminance value obtained by the light meter 12, the MCU 10
seeks a control value. The shutter controller 16 effects its operation in
accordance with this value.
Designated at SW1 is a first exposure control mode setting switch for
setting an exposure mode. The symbol SW2 represents a second exposure mode
setting switch for setting an exposure mode. The setting switches SW1, SW2
are prescribed as shown in Table 1 in accordance with the exposure control
mode. If the exposure mode is like this: a shutter speed auto setting
mode--an A mode (diaphragm preference exposure control mode) or a P mode
(program exposure control mode)--, the first exposure setting switch SW1
is turned off. At that moment, if the second exposure mode setting switch
SW" is turned on, the exposure control mode becomes the A mode. Whereas
turned off, it becomes the P mode. If the exposure control mode is like
this: a shutter speed manual setting mode--an S mode (shutter speed
preference exposure control mode) or an M mode (manual exposure control
mode)--, the first exposure mode setting switch SW1 is turned on. At that
time, if the second exposure mode setting switch SW2 is turned on, the
exposure control mode becomes the M mode. Whereas if turned off, it
becomes the S mode.
TABLE 1
______________________________________
SW1 SW2
______________________________________
P OFF OFF
A OFF ON
S ON OFF
M ON ON
______________________________________
The switch SW3 is a synchro mode changeover switch, interlocking with an
unillustrated [SLW ] button, for changing over setting/releasing of slow
synchro. When depressing the unillustrated [SLW ] button, the synchro mode
changeover switch SW3 is turned on. Upon a release of the depression, the
synchro mode changeover switch SW3 is turned off. Every time the synchro
mode changeover switch SW3 is turned on by pushing this [SLW ] button,
setting/releasing of slow synchro are alternately changed over, and
setting remains invariable even by continuous pushing. Upon a release of
the slow synchro mode, a normal synchro mode is set.
During the shutter speed auto setting mode, the slow synchro mode is not
set, and the flash apparatus 20 is made to function. In this case, the MCU
10 calculates a shutter speed on the basis of subject luminance
information given from the light meter 12. A failure of photographing due
to a hand deflection is prevented by restricting the arithmetic result
from being lower than a hand deflection limit shutter speed (e.g., 1/60
sec). This speed restriction is released by changing the slow synchro mode
from the non-setting state to the setting state. The speed restriction
does not function during the shutter speed manual setting mode. The MCU 10
changes over a permission and inhibition of the function of the
above-mentioned speed restriction, depending on the states of the first
exposure mode setting switch SW1 and the synchro mode changeover switch
SW3 (the details will be given latter).
Designated at SW4 is a release switch interlocking with an unillustrated
release button. The switch SW4 is turned on when pushing the unillustrated
release button, and a release sequence is thereby started.
A switch or synchro switch SW5 is turned on when shutter leading curtain
running is completed and turned off interlocking with trailing curtain
running.
The flash apparatus 20 built in or mountable in a camera transmits its
power-on as a ready signal to the MCU 10 and starts flashing by a synchro
output from the MCU 10. The flash apparatus 20 stops flashing on receiving
a stop signal from the light adjuster 11.
FIG. 2 is a flowchart of a main routine within the MCU 10.
In step #11, a subroutine call is effected with respect to a set routine.
Set are a variety of parameters within the MCU 10 in accordance with the
states of the set device 13, the first exposure mode setting switch SW1,
the second exposure mode setting switch SW2 and the synchro mode
changeover switch SW3.
In next step #12, a photometric routine undergoes a subroutine call. A
photometric output from the light meter 12 undergoes an A/D conversion
into luminance information. The action moves to next step #13.
In step #13, an arithmetic routine is subjected to the subroutine call. An
APEX arithmetic operation is performed in accordance with the luminance
information obtained in step #12 and the set value information obtained in
step #11. A control value is thus obtained.
In next step #14, a delay routine undergoes the subroutine call. Obtained
are indication data corresponding to the control value acquired in step
#13 and the set value determined in step #11. The indication data are sent
to the indicator 14 where indications required are given. Next, the action
moves to step #15.
In step #15, an interrupt is permitted. The action returns to step #11,
wherein the processes described above are repeated.
FIG. 3 is a flowchart of a timer interrupt processing routine which will be
executed after permitting the interrupt in step #15 of FIG. 2. When the
timer interrupt is permitted, there is effected a change to a process of
main routine in the course of executing the main routine of FIG. 2 by the
timer interrupt per 1[ms]. In step #21, on/off states of the release
switch SW4 are checked. If in the off-state, the action returns directly
to the process of main routine. Whereas in the on-state, the action moves
to step #22 where the release sequence is started.
In step #22, an electromagnet Mg for holding the leading and trailing
curtains of the shutter is energized, thus holding the shutter by an
electric system.
In step #23, a motor is reversely rotated by driving the motor controller
17 to initiate a mirror-up.
Set in step #24 is a light adjustment sensitivity of the light adjuster 11
in accordance with a film sensitivity set in step #11 of FIG. 2.
Controlled in step #25 is a diaphragm according to the diaphragm value
obtained in step #13 of FIG. 2 by driving the diaphragm controller 15.
In step #26, with a detection of completion of the mirror-up by use of an
unillustrated mirror switch, the motor is stopped by driving the motor
controller 17.
In step #27, the shutter is controlled according to the shutter speed
obtained in step #13 of FIG. 2 by driving the shutter controller 16. In
the meantime, the synchro switch SW5 continues to be monitored. A synchro
output is given forth by turning on the synchro switch with completion of
shutter trailing curtain running, thereby controlling the flash apparatus
20.
In step #28, the motor is rotated forwards by driving the motor controller
17, thus performing a step of mirror-down. A shutter charge and a film
take-up are then effected. Finally, the motor is stopped with a variation
in an unillustrated take-up completion switch. A series of release
sequences come to an end in the manner discussed above.
FIG. 4 is a flowchart of a subroutine which is a part of the set routine
where the subroutine call is performed in step #11 of FIG. 2 and is also
associated with the synchro mode.
Checked in step #31 are on/off states of the synchro mode changeover switch
SW3 interlocking with an unillustrated [SLW ] button. If turned on by
depressing the button, the action moves to step #32. Whereas if kept off
without pushing the button, the action moves to step #33.
Examined in step #32 is whether the exposure control mode is the S or M
mode. If it comes under the S or M mode, the action moves to step #40. If
it comes under the A or P mode, the action moves to step #34.
In step #33, a button flag is set to 0. In step #34, whether the button
flag is 0 or 1 is checked. If the flag is 1, the action skips over to step
#39. If the flag is 0, the action moves to next step #35.
When the unillustrated [SLW ] button is not depressed, setting of the
button flag can be changed over with the flag being 0 while the synchro
mode changeover switch SW3 is kept off. When the unillustrated [SLW ]
button is continuously depressed, however, the flag remains to be 1, while
a change in setting is made invalid.
In step #35, whether or not the slow synchro mode is set is checked
depending on setting or non-setting of a slow synchro flag. If the slow
synchro flag is set, and when being set to the slow synchro mode, the
action moves to step #36. If the slow synchro flag is reset, and when slow
synchro setting is not done, the action moves to step #37.
If this slow synchro flag is set, and when slow synchro setting is done,
there is released the restriction of the above-mentioned hand deflection
limit shutter speed which works during the shutter speed control in the
shutter speed auto setting mode. If the slow synchro flag is reset, and
when slow synchro setting is not effected, the restriction thereof is not
released. During the shutter speed manual setting mode, the restriction of
the hand deflection shutter speed is always released irrespective of the
state of this slow synchro flag.
In step #36, the slow synchro setting flag is reset, and the action moves
to step #38.
In step #37, the slow synchro setting flag is set.
In next step #38, the button flag is set, and the action moves to step #39.
In step #39, a warning flag of the exposure control mode is reset, and the
action is returned.
In step #40, the warning flag of the exposure control mode is set, and the
action is returned.
FIG. 5 is a flowchart of an indication routine which is a part of the
indication routine where the subroutine call is performed in step #14 of
FIG. 2 and is associated with the slow synchro.
In step #51, whether the exposure control mode is the S or M mode is
checked. If it comes under the S or M mode, the action moves to step #53.
If it comes under the A or P mode, the action moves to step #52.
Examined in step #52 is whether the slow synchro setting flag is set or
not. If set, the action moves to step #54. If reset, the action moves to
step #53.
In step #53, a mark [SLOW ] is turned off, and the action moves to step
#55.
In step #54, the mark [SLOW ] is turned on, and the action moves to step
#55.
In step #55, whether or not the warning flag of the exposure control mode
is set is checked. If set, the action moves to step #57. If reset, the
action moves to step #56.
In step #56, blinking of the exposure control mode is released, and the
action is returned.
In step #57, the exposure control mode is brought into the blinking state,
and the action is returned.
Where the unillustrated [SLW ] button is not pushed, in the routine of FIG.
4, the action modes from step #31 to step #33, and the button flag is
reset. The action moves to step #39, and the mode warning flag is reset.
Then returns the action. On this occasion, in a flow of action in FIG. 5,
if the exposure mode is the S or M mode, the action moves from step #51 to
step #53. Regardless of the slow synchro flag, the mark [SLOW ] is
invariably turned off. On the other hand, if the exposure control mode is
A or P mode, in the flow of action in FIG. 5, the action moves from step
#51 to #52. The on/off states of the mark [SLW] are switched over
corresponding to the slow synchro flag. If the slow synchro flag is set,
the action moves to step #54, and the mark [SLOW ] is turned on. If the
slow synchro flag is reset, the action moves to step #53, and the mark
[SLOW ] is turned off. The warning flag is reset, and hence the action
moves from step #55 to step #56. A blinking warning state of the exposure
control mode is not developed.
If the exposure control mode is the A or P mode, the synchro mode
changeover switch SW3 is turned on by depressing the unillustrated [SLW ]
button. On this occasion, in a flow of action in FIG. 4, the action moves
from step #31 to step #32 and further to step #34. Besides, the button
flag is 0 at the starting time before depressing the [SLW ] button.
Therefore, the action moves to step #35. If the slow synchro is set before
pushing the [SLW ] button, the action moves to step #36 to release slow
synchro setting. If the slow synchro mode is not set before pushing the
unillustrated [SLW ] button, the action moves to step #37 where the slow
synchro mode is set. In either case, it follows that the synchro mode is
inverted by manipulating the [SLW ] button. When the action moves to step
#38, the button flag becomes 1. The action moves to step #39 where the
mode warning flag is reset. Even when continuously pushing the
unillustrated [SLW ] button, since the flag is 1, the action next jumps
from step #34 to step #39. For this reason, setting remains invariable. A
change of setting involves the steps of temporarily releasing the
depression of the unillustrated [SLW ] button and turning off the synchro
mode changeover switch SW3. In the flow of action in FIG. 5, the action
moves from step #51 to step #52. The on/off states of the mark [SLOW ] are
switched over in accordance with the slow synchro flag. The warning flag
is reset, and hence the action moves from step #55 to step #56, resulting
in no blinking warning state of an exposure control mode mark.
When exposure control mode is the S or M mode, the synchro mode changeover
switch SW3 is turned on by depressing the unillustrated [SLW ] button. In
FIG. 4, the action moves from step #31 to step #32 and further to step #40
where the mode warning flag is set. In the flow of action in FIG. 5, the
action moves from step #51 to step #53 where the mark [SLOW ] is always
turned off irrespective of the slow synchro flag. Since the warning flag
is set, the action moves from step #55 to step #57, resulting in the
blinking warning state of the exposure control mode mark. Hence, the mode
is, it can be comprehended, such an exposure control mode as to make the
slow synchro mode impossible of setting. On separating the hand from the
unillustrated [SLW ] button, in the flow of action of FIG. 4, the action
moves like this: step #31--step #33--step #39. Therefore, as discussed
above, the warning indication disappears.
As described above, the slow synchro flag is invertible only when the
exposure control mode is the A or P mode. When the exposure control mode
is the S or M mode, no indication of slow synchro is given. This does not
imply that setting is released. In slow synchro set in the A or P mode,
the original indication thereof is attainable by setting the mode back to
the A or P mode even if the indication disappears when being set to the S
or M mode.
The slow synchro mode flag and other setting information are stored in the
EEPROM built in the MCU 10. It is therefore possible to resume the
manipulation of the camera by setting before turning off the power supply
when turning on the power supply once again after a turnoff of the power
supply.
The following is an explanation of relations between the respective
switches and the indications.
FIGS. 6A through 6C, 7A and 7B show the indications associated with slow
synchro of the camera according to the present invention.
FIGS. 6A-6C show the indications in such a case that the slow synchro mode
has already been set in the initial state. Referring to FIG. 6A, the S
mode is selected as an exposure control mode (31a in the Figure), so that
the mark [SLOW ] is turned off. Next, the A mode (31b in the Figure) is
selected from the state of FIG. 6A. At this time, if the slow synchro flag
is set, as shown in FIG. 6B, a [SLOW ] mark 33d is turned on. Further, the
synchro mode changeover switch SW3 is turned on by depressing the
unillustrated [SLW ] button. As illustrated in FIGS. 6B and 6C, the mark
[SLOW ] is turned off. The synchro mode changeover switch SW3 is turned
on by depressing the unillustrated [SLW ] button once again. The display
reverts to the state of FIG. 6B.
FIGS. 7A and 7B show indications when the slow synchro mode is not set in
the initial state. Referring to FIG. 7A, the mark [SLOW ] of the s | | |
