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Description  |
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BACKGROUND OF THE INVENTION
The invention relates to a photographic camera, and more particularly, to a
camera which permits a selection among a plurality of photographing modes
including an automatic exposure mode, a manual exposure mode, an average
photometry mode, a localized or spotwise photometry mode and the like.
As is well recognized, the photometry used in the conventional cameras can
be categorized into an average photometry and a localized (or spotwise)
photometry. The average photometry can be classified into a photometry
averaged over the entire image field and another which is centrally
emphasized, the latter being generally employed. Such average photometry
produces a passable result for the typical object and over the localized
photometry in respect of the ease of use, and accordingly, this average
photometry is employed in most cameras.
The localized or spotwise photometry can be effectively used for an object
having a high ratio of highlight and shadow when it is desired to control
the exposure in accordance with the brightness of either the highlight or
the shadow. However, it requires a troublesome operation and is likely to
cause a photographing operation with an improper exposure. In the past,
there has been a camera offered on the market which allows the photometry
of only the central region of an image field, but this makes the
photographic composition difficult. Accordingly, at the present time,
cameras seldom adopt such a technique.
For the reasons mentioned above, the average photometry technique
represents an excellent technique as compared with the localized or
spotwise photometry when taking a picture of an ordinary object being
photographed. However, in practice, objects being photographed are not
limited to those having a reduced ratio of highlight and shadow, but
include a number of objects having a greater ratio of highlight and shadow
such as objects in the rear light, objects on a stage and objects in a
composition which is formed when viewing the outdoors through a window. In
particular, it is to be noted that the chance to take a picture of an
object having a higher ratio of highlight and shadow increases as a
photographer makes progress in his photographing skill. If an automatic
exposure camera which operates on the basis of the average photometry is
used to take a picture of an object having a high ratio of highlight and
shadow, the exposure is controlled in accordance with the average
brightness of the object, and hence prevents the intended composition of a
photographer from being achieved when it is desired to control the
exposure in accordance with the brightness level of a selected region of
such object.
In the prior art practice, when taking a picture of such a special object,
a so-called spot meter which utilizes a very limited angle for photometry
is used to determine the brightness of an object being photographed at a
plurality of locations. Based on the information representing the
brightness of the object thus obtained and the intended composition to
impart a proper exposure to a selected region and to determine the
brightness level of the shadow, exposure factors such as a diaphragm
aperture and an exposure period are determined, followed by taking a
picture by manual operation of the camera. Where an object is accessible
as when taking a picture in a studio, an incident-light exposure meter is
used to determine the brightness of an object being photographed at a
plurality of desired locations in order to determine exposure factors in
the similar manner as mentioned above, thus allowing a picture to be taken
by manual operation. However, the use of an exposure meter which is
separate from the camera to perform the localized or spotwise photometry
in order to determine the exposure factors requires a troublesome
procedure, an increased length of time and a complex calculation, all of
which represent disadvantages.
A so-called multi-mode camera is available in the prior art. This
represents a camera which allows a selection among a plurality of
photographing modes including an automatic and a manual exposure mode.
However, such camera does not afford a display of adequate and full
photographing information within a finder since such information varies
from mode to mode.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a camera of the multi-mode type
having a finder within which a photographing information display
comprising a linear succession of a plurality of display regions is
defined so that photographing information is indicated in the form of a
bar by activating the display from a display region located at one end
thereof to a particular display region which corresponds to the particular
photographing information to be indicated and in which, whenever a
photographing mode is changed, the display is once entirely deactivated,
followed by the activation of the display from a display region located at
one end thereof to another display region which corresponds to the
photographing information to be used in a new photographing mode, thus
providing a positive indication that the photographing mode has been
changed.
It is another object of the invention to provide a camera having localized
or spotwise photometric means which is used to obtain the values of the
brightness of an object being photographed at a plurality of locations and
in which such values as well as result of arithmetic operations performed
on these values are displayed, with the values of the brightness being
directly displayed while the result of arithmetic operations are corrected
before display if an exposure correction is made.
It is a further object of the invention to provide a camera having
localized or spotwise photometric means which may be used to determine the
values of brightness of an object being photographed at a plurality of
locations, which values are subject to an arithmetic operation to
determine an exposure level, and also having a finder in which a first and
a second photographing information display are defined, each comprising a
linear succession of a plurality of display regions, the photometric
values obtained at individual locations being indicated by separately
activating corresponding display regions of the first display and the
result of the arithmetic operation being indicated in the form of the bar
by activating the second display from a display region located at one end
thereof to another display region which corresponds to the result.
It is still another object of the invention to provide a camera having
localized or spotwise photometric means which is used to determine
photometric values of an object being photographed at a plurality of
locations, which values are indicated within a finder on a photographing
information display comprising a linear succession of a plurality of
display regions, and in which a photometric value which has already been
determined is fixedly displayed on a corresponding display region of the
display while a photometric value which is currently being determined is
displayed on a corresponding display region of the display. It is a
corollary object of the invention to provide a camera of the type
mentioned above in which a photometric value which is is currently
determined being displayed on a corresponding display region of the
display in a flashing mode. It is an associated object of the invention to
provide a camera of the type mentioned above in which a photometric value
which is being currently determined is predominantly displayed whenever a
display region which is used for the flashing display coincides with the
display region in which the previous photometric value is to be fixedly
displayed.
It is a still further object of the invention to provide a camera having
localized or spotwise photometric means which is used to obtain values of
the brightness of an object being photographed at a plurality of locations
in a time sequence and in which an arithmetic operation is performed on
these values in order to control an exposure, with these photometric
values and/or results of the arithmetic operation being properly stored so
that they are displayed in a photographing information display whenever
such photometric values and/or results of the arithmetic operation are
located within the extent of the display while a display region or display
pattern representing an overexposure or an underexposure is activated if
they are located outside the extent of the display, and in which whenever
a new brightness value is inputted, the arithmetic operation is performed
again, thereby assuring that a correct result of arithmetic operation is
always available.
It is an additional object of the invention to provide a camera which
permits an average photometry mode and a localized or spotwise photometry
mode to be selectively used and in which when changing from the average to
the spotwise photometry, the spotwise photometry mode can be established
by actuating an operating member and can be reset to the average
photometry mode whenever the photographing operation with the spotwise
photometry is completed.
It is a yet additional object of the invention to provide a camera which
permits an average photometry mode and a localized or spotwise photometry
mode to be selectively used and in which the photographing mode is
automatically changed from the average photometry to the spotwise
photometry in response to an operation to input a spotwise photometric
value.
It is yet another object of the invention to provide a camera which permits
an average photometry mode and a localized or spotwise photometry mode to
be selectively used and having localized or spotwise photometric means to
obtain spotwise photometric values on which an arithmetic operation is
applied to determine an exposure level during the localized or spotwise
photometry mode, the camera also including a data erasure member to cancel
the spotwise photometric values and the corresponding results of the
arithmetic operation, the operation of the erasure member automatically
changing the photographing mode from the localized or spotwise photometry
to the average photometry mode.
It is a yet further object of the invention to provide a camera having
localized or spotwise photometric means which is used to obtain values of
the brightness, from which an arithmetic mean or a weighted mean is
derived to determine an exposure level during a normal spotwise
photographing mode, from which the maximum value is chosen to determine
another exposure level which is by a given number of exposure steps above
such maximum value during a highlight referenced photographing mode, and
from which the minimum value is chosen to determine a further exposure
level which is by a given number of exposure steps below the minimum value
during a shadow referenced photographing mode, thereby allowing the
operation of the camera to be selectively changed between these three
modes. It is an attendant object of the invention to provide such a camera
in which the highlight- or shadow-referenced photographing mode is
disabled whenever at least one or more spotwise photometric values are not
inputted.
It is a yet additional object of the invention to provide a camera having
localized or spotwise photometric means which is used to obtain values of
the brightness, which are then stored and in which the maximum value of
the brightness is chosen as a reference to determine an exposure level
which exceeds the reference by a given number of exposure steps so that an
exposure period is delayed by an amount corresponding to the given number
of exposure steps as compared with a shutter period which corresponds to a
proper exposure for the maximum value and in which the delayed exposure
period is displayed within a finder of the camera. It is an attendant
object of the invention to provide such a camera in which whenever a fresh
value of the brightness is inputted which exceeds the maximum value of the
brightness, the fresh value is chosen as the reference to repeat the
arithmetic operation to determine the shutter period.
It is also an object of the invention to provide a camera having localized
or spotwise photometric means which is used to obtain values of the
brightness which are then stored and in which the minimum value is chosen
as a reference to determine an exposure level which is below the reference
by a given number of exposure steps so that an exposure period which is
actually used may be shortened by an amount corresponding to the given
number of exposure steps from an exposure period which represents a proper
exposure for the minimum value and in which such shortened exposure period
is also displayed within a finder of the camera. It is an attendant object
of the invention to provide such a camera in which whenever a fresh value
of the brightness is inputted which is below the minimum value, the fresh
value is chosen as the minimum value to repeat the arithmetic operation to
determine an exposure period.
It is another object of the invention to provide an automatic exposure
camera including a storage member, commanding an exposure level to be
stored, and in which during an initial photographing operation after a
stored exposure level photographing mode has been selected by the
actuation of the storage member, an exposure level which is actually used
during this photographing operation and which is determined in accordance
with exposure factors such as a preset diaphragm aperture, film speed or
the like as well as an exposure period which is automatically controlled
in accordance with the brightness of an object being photographed is
stored, so that unless the stored exposure level photographing mode is
reset, the given exposure level is maintained during subsequent
photographing operations. It is an associated object of the invention to
provide such a camera in which the stored value of the exposure level as
well as a value of the exposure level which is determined in accordance
with the photometric value being currently determined are displayed
together within a finder of the camera. It is an attendant object of the
invention to provide such a camera in which after the storage of the
exposure level, a change in one of exposure factors causes the stored
value of the exposure level to be varied in a corresponding manner. It is
a corollary object of the invention to provide such a camera in which
after the storage of the exposure level, the stored value of the exposure
level is varied in response to an exposure correction so that the new
exposure level represents a sum of the old exposure level and the amount
of correction.
It is a further object of the invention to provide a camera having
localized or spotwise photometric means which is used to obtain
photometric values of an object being photographed at various locations
and in which such photometric values as well as results of an arithmetic
operation performed thereon are displayed as deviations from a standard
exposure level which is calculated in accordance with a selected exposure
period, diaphragm aperture, film speed and the like. It is a corollary
object of the invention to provide such a camera in which the exposure
level which is determined on the basis of results of the arithmetic
operation is brought into coincidence with a fixed index representing a
standard exposure level and in which the various locations on an object
being photographed, the spotwise photometry of which has been made, are
taken with a differential exposure level from the standard level which
corresponds to the deviation from the fixed index.
It is an additional object of the invention to provide a camera of
automatic exposure control type in which whenever an electronic flash is
mounted on the camera, an exposure period is automatically established
which is synchronized with the operation of the electronic flash and in
which a fixed point index is caused to appear within a finder to indicate
brightness information as a deviation from the index.
In accordance with the invention, there is provided a multi-mode camera in
which whenever a photographing mode is changed, all the display regions of
a photographing information display are once deactivated, followed by the
activation of selected display regions, thereby providing a positive
indication that the photographing mode has been changed.
Values of the brightness which are obtained by the localized or spotwise
photometric means are displayed without any correction while results of an
arithmetic operation performed on these values are displayed with
correction. In this manner, the result of the arithmetic operation,
representing an exposure level to be used, is allowed to shift through a
plurality of distributed values of the brightness.
Spotwise photometric values are displayed in terms of points while the
result of the arithmetic operation is displayed in the form of a bar
graph, thereby facilitating a discrimination therebetween. The bar graph
display assists a photographer to get the sense of the result of the
arithmetic operation.
Spotwise photometric values which have already been inputted are fixedly
displayed while a spotwise photometric value which is being currently
determined is also displayed, thereby facilitating a recognition of the
both.
In the event the spotwise photometric values and the result of the
arithmetic operation lie outside the display regions of the photographing
information display, a positive indication of an overexposure or
underexposure is given, thereby preventing an inadvertent photographing
operation with an improper exposure. Even though the overexposure or
underexposure is displayed, the spotwise photometric values as well as the
result of the arithmetic operation are properly stored. Hence, if the
spotwise photometric values and the result of the arithmetic operation
come into the display regions of the display due to a subsequent change in
other exposure factors, they can be properly displayed.
The photographing mode is automatically changed from the localized or
spotwise photometry mode to the average photometry mode in response to the
completion of the spotwise photometry photographing operation, thus
avoiding the likelihood that improper pictures may be taken as a result of
a continued photographing operation in the spotwise photometry mode. The
reason for resetting the operation to the average photometry mode after
completion of the spotwise photometry operation is because the spotwise
photometry is only rarely used and because the average photometry
generally produces a passable result.
The operation is automatically changed from the average photometry to the
spotwise photometry mode in response to an operation to input a spotwise
photometric value. This eliminates the need for the provision of a
separate member which is to be disposed on the camera to select the
spotwise photometry mode, thus effectively preventing a failure in the
photographing operation as a result of an inadvertent operation of or
forgetting to operate such member.
The provision of a data erasure member permits the spotwise photometric
values and the result of the arithmetic operation to be cancelled,
facilitating the spotwise photometry to be repeated after it has once been
attempted. At the same time, the actuation of the erasure member
automatically changes the operation from the spotwise photometry to the
average photometry mode, providing a greater convenience in use.
A selection is enabled among a normal spotwise photographing mode in which
an exposure level is determined on the basis of an arithmetic mean or a
weighted mean of photometric values obtained with the spotwise photometric
means, a highlight referenced photographing mode in which an exposure
level is determined which exceeds, by a given number of exposure steps, a
reference which represents the maximum one of the photometric values, and
a shadow referenced photographing mode in which an exposure level is
determined which is, by a given number of exposure steps, below a
reference which represents the minimum one of the photometric values. Such
selection enables a photographing operation which fully reflects the
composition intended by a photographer. The highlight or the shadow
referenced photographing mode is disabled if at least one or more
photometric values from the spotwise photometry is not inputted, thus
eliminating the need to reset such mode if it is inadvertently selected
and thus avoiding the likelihood to miss a shutter chance.
In the highlight referenced photographing mode, an exposure period is
delayed by an amount corresponding to the given number of exposure steps,
as compared with an exposure period which would represent a proper
exposure for the maximum value of the brightness. This permits a picture
to be taken with an appropriate ratio of highlight and shadow, as
referenced to an intended region of an object being photographed. The
display of an actual exposure period within a finder assists a
photographer in taking a picture since it is available to him beforehand.
Furthermore, if a fresh value of the brightness is inputted which exceeds
the maximum value of the brightness, the arithmetic operation to determine
an exposure period is automatically repeated, allowing a photographer to
take a picture while only paying attention to the exposure period
displayed within the finder and without being troubled by a complex
calculation.
In the shadow referenced photographing mode, an exposure period is
shortened, by an amount corresponding to a given number of exposure steps,
as compared with an exposure period which would represent a proper
exposure for the minimum value of the brightness. This also permits a
photographer to take a picture with an appropriate ratio of highlight and
shadow as referenced to a desired region of an object being photographed.
The display of an actual exposure period within the finder assists a
photographer in taking a picture since it is available to him beforehand.
Furthermore, if a fresh value of the brightness is inputted which is below
the minimum value of the brightness, the arithmetic operation to determine
an exposure period is automatically repeated, allowing a photographer to
take a picture while only paying attention to an exposure period displayed
within the finder and without being troubled by a complex calculation.
When a storage member is actuated, an exposure level which is stored during
the initial automatic exposure is utilized during the subsequent
photographing operation, permitting a plurality of frames to be exposed at
the same exposure level. The stored exposure level is displayed within a
finder concurrently with an exposure level which corresponds to the
brightness of an object being photographed which is being currently
determined, thus facilitating a comparison of the exposure levels. In the
event an exposure factor other than the stored exposure level varies, the
stored exposure level is also varied in accordance with the change in the
exposure factor, allowing pictures to be taken always at a given exposure
level. If an exposure correction is made, the stored exposure level can be
changed in accordance with such correction, thus allowing the exposure
level to be shifted only for those frames which require such correction.
An exposure level which is based on the spotwise photometric values and the
result of the arithmetic operation is displayed as a deviation from a
standard exposure level, providing a clear indication of the distribution
of the brightness of an object being photographed as well as its deviation
from the standard exposure level. This greatly facilitates a multiple
point photometry during a manual photographing operation.
When utilizing an electronic flash, an exposure level which will be
attained under natural light alone at a timing which is synchronized with
the operation of the electronic flash is displayed as a deviation from the
standard exposure level, allowing a photographer to recognize the degree
of exposure which would be achieved with natural light alone. Hence, it is
possible to determine beforehand whether or not the brightness of an
object being photographed is high enough to obviate the use of an
electronic flash or the degree to which a background will be over- or
under-exposed when performing a daytime synchronized photographing
operation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a camera constructed in accordance with one
embodiment of the invention;
FIG. 2 is a top plan view of the camera shown in FIG. 1;
FIG. 3 is a schematic side elevation of the optics contained within the
camera of FIG. 1;
FIG. 4 is a front view of a photometric light receiver contained in the
optics of FIG. 3;
FIG. 5 is a block diagram of the general arrangement of an electrical
circuit contained in the camera shown in FIG. 1;
FIG. 6 is a block diagram of the internal arrangement of a microcomputer
serving as a central processing unit shown in FIG. 5;
FIG. 7 is a circuit diagram of an interface utilized as a peripheral unit
of the microcomputer shown in FIG. 6;
FIG. 8 is a circuit diagram of a head amplifier shown in FIG. 5;
FIG. 9 is a circuit diagram of an analog exposure information introduction
circuit and a second selection circuit, both shown in FIG. 5;
FIG. 10 is a circuit diagram of an over- and under-exposure decision
circuit associated with an electronic flash and a first comparator, both
shown in FIG. 5;
FIG. 11 is a circuit diagram of an electrical circuit of a power supply
sustain circuit shown in FIG. 5;
FIG. 12 is a circuit diagram of a trigger timing control circuit shown in
FIG. 5;
FIG. 13 is a circuit diagram of a battery checker circuit and a power
supply reset circuit, both shown in FIG. 5;
FIG. 14 is a circuit diagram of a decision circuit associated with an
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