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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photographic camera for photographing an
object onto a film.
2. Description of the Prior Art
A camera capable of changing over between a real focal length photographing
mode or normal photographing mode for photographing a real focal length
photographing range or normal photographing range on a film and printing
the said range and a pseudo focal length mode in which a range narrower
than the real focal length photographing range is indicated and the
indicated range alone is printed, has already been proposed in Japanese
Laid Open Patent No. 26721/79 and in U.S. Pat. No. 3,490,844.
However, if such a camera is constructed so that the brightness of the
whole real focal length photographing range is measured photometrically by
a light measuring means and an exposure control is made on the basis of
results of the light measurement, then even a photographing range not
printed on a photographic paper in the pseudo focal length photographing
mode will be measured photometrically. Thus, if an exposure control is
made on the basis of such a result in the pseudo focal length
photographing mode, there is a possibility that an appropriate exposure
will not be obtained with respect to the printed range in the pseudo focal
length photographing mode. For example, if an object having an extremely
high luminance as compared with other objects, such as the sun, is located
in a corner of the real focal length photographing range, the high
luminance object (the sun) will not be printed on a photographic paper in
the pseudo focal length photographing mode. If in such a situation there
is made an averaged light measurement for the whole real focal length
photographing range and an exposure control is made on the basis of
results obtained, an extreme under-exposure will result with respect to an
object of the range printed in the pseudo focal length photographing mode.
Conversely, in the case where an object illuminated with a spot light and
thus having a luminance much higher than that of other objects is located
centrally of the real focal length photographing range, if there is made
an averaged light measurement for the whole real focal length
photographing range and an exposure control is performed on the basis of
results obtained, an extreme overexposure will result with respect to an
object of the range printed in the pseudo focal length photographing mode.
This can also be said of a printer of the type in which an image memorized
on a photographed film is printed on a photographic paper. More
particularly, in the case of a frame photographed in the pseudo focal
length mode, only a part of the photographed range on the frame is printed
on the photographic paper. Thus, if the brightness of the entire range of
the frame is measured and exposure value and color balance are determined
on the basis of results obtained, then even the range not printed on the
photographic paper is subjected to the light measurement and the result is
taken into account in the determination of exposure value and color
balance. Therefore it is possible that a print having appropriate density
and color balance will not be obtained with respect to the range printed
in the pseudo focal length photographing mode.
Further, where a frame photographed in the pseudo focal length
photographing mode in the above camera is enlarged to a print of the same
size as that of a frame photographed in the real focal length
photographing mode, the print enlargement ratio inevitably becomes larger
in the pseudo focal length photographing mode frame than in the real focal
length photographing mode frame. Consequently, in the case of printing the
frame photographed in the pseudo focal length photographing mode, blurring
of the object image on the film caused by vibration of the camera, which
has not caused any problem in the real focal length photographing mode,
becomes conspicuous and therefore image quality of the print is degraded.
With respect to the image quality of the print, as the enlargement ratio in
printing becomes larger, the film particles become more conspicuous on the
print. The result is that a poor print is obtained especially in the case
of a high sensitivity film poor in particle properties.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a camera capable of
affording an appropriate exposure in the pseudo focal length photographing
mode mentioned above.
It is another object of the present invention to provide a camera capable
of preventing the deterioration of the image quality caused by the
enlargement ratio of the printing in the pseudo focal length photographing
mode being larger than that in the normal photogaphing mode.
Other objects and features of the invention will become apparent from the
following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a camera according to an embodiment of the
present invention;
FIG. 2 is a top view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a sectional view showing a construction of a finder optical
system and a range finding optical system both used in the camera;
FIG. 5 is a schematic view showing printing range in the pseudo focal
length photographing mode;
FIG. 6 is a schematic view showing a display in the camera finder field;
FIG. 7 is a sectional view showing a relation between a photographing range
of a photographing lens and a light measuring range of a light measuring
optical system both used in the camera;
FIGS. 8 and 9 illustrate display modes of a liquid crystal display used in
the camera;
FIG. 10 illustrates the camera with a back cover open, viewed from the
back;
FIG. 11 is an enlarged front view of a code printing unit used in the
camera, viewed from the back;
FIG. 12 is a longitudinal sectional view of the code printing unit;
FIG. 13 is a partially enlarged transverse sectional view of the code
printing unit;
FIG. 14 illustrates a film on which are printed the code signals, viewed
from the back;
FIG. 15 illustrates code signals printed on the film;
FIG. 16 is an electrical circuit diagram of the camera;
FIG. 17 is a block diagram showing a construction of an automatic focus
adjusting circuit used in the camera;
FIG. 18 is a graph showing a relation between aperture and exposure time
and also showing a flash emission timing;
FIG. 19 is a graph showing a relation between aperture and exposure time at
the time of change-over to flash photography;
FIGS. 20A, 20B, 20C and 21 are flow charts showing operation of a
controlling microcomputer used in the camera;
FIG. 22 is a flow chart showing details of step S8 therein;
FIG. 23 is a schematic view showing operation thereof in a typical manner;
FIGS. 24, 25 and 26 are each a flow chart showing operation of a
microcomputer for display;
FIG. 27 is a block diagram showing an automatic printer used in the system
of this embodiment; and
FIG. 28 is a time chart showing operations thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention will be described in detail
hereinunder with reference to the accompanying drawings.
In FIG. 1, which is a perspective view of a camera embodying the present
invention, the reference numeral 2 denotes a camera body; numeral 4
denotes a shutter release button; numeral 6 denotes a date selection
switch for selecting whether a date is to be printed or not on a
photographic paper during the printing operation; numeral 8 denotes a
trimming setting button for setting whether pseudo focal length
photographing mode is set or not and its printing size; and LCD.sub.1
represents a liquid crystal display for displaying various data related to
photographing. The shutter release button 4, date selection switch 6 and
trimming setting button 8 are disposed on an upper surface of the camera
body 2 as shown in the top view of FIG. 2. The date selection switch 6 is
a slide type; in its position shown, the date is printed, while when it is
slid in the X direction in the figure, the date is no longer printed.
Either of the real focal length photographing mode or normal photographing
mode and the pseudo focal length photographing mode, and the ratio of
trimming in the latter are determined according to the number of
depressions of the button 8. As will be described later, when a film
having a sensitivity below ISO 400 is loaded, the trimming setting button
8 is not depressed at all, under which condition the pseudo focal length
photographing mode is not selected and the whole of a real focal length
photographing range or normal photographing range is printed. When the
trimming setting button 8 is depressed once, a trimming "1" mode is
obtained in which a little narrower photographing range than the real
focal length photographing range is printed. Depressing it twice affords a
trimming "2" mode of a still narrower printing range, and depressing it
three times results in a trimming "3" mode of the narrowest printing
range. If it is further depressed, there will be obtained a close-up mode
as will be described later. A still further depression of the trimming
setting button 8 will result in return to the real focal length
photographing mode. Details on this respect will be set forth later.
In FIG. 1, moreover, the numeral 12 denotes a flash unit portion; numeral
14 denotes a finder window; numeral 16 denotes a finder illuminating
window; and numerals 18a and 18b represent a pair of range finder windows.
These are arranged on a front face of the camera body 2 as shown in the
front view of FIG. 3. Numerals 20 and 22 denote a photographing lens and a
light measuring window for automatic exposure control.
FIG. 4 is a sectional view showing a finder optical system and a range
finding optical system both used in such camera. In FIG. 4, the finder
optical system is constituted by an inverted Galilean type optical system
comprising an objective lens L.sub.1 having a negative refractive power
and an eyepiece lens L.sub.2 having a positive refractive power, both
disposed in the interior of the finder window. Between the objective lens
L.sub.1 and the eyepiece lens L.sub.2 is disposed a half mirror H whereby
light which has been reflected by a mirror M after passing through a
liquid crystal display LCD.sub.2 disposed behind the finder lighting
window 16 is conducted to the finder. On the other hand, behind the range
finder window 18a is disposed a light emitting diode 24 for range finding
to project an infrared light beam to an object through a projection lens
L.sub.3. Light reflected from the object is detected by a light detecting
element 26 for range finding through a light receiving lens L.sub.4
disposed behind the range finder window 18b, and from the state of light
detected the distance to the object is determined. This range finding
principle is already well known, so its details are here omitted.
The printing range in the selection of pseudo focal length photographing
mode will now be explained with reference to FIG. 5, which is a front view
showing one exposure plane of an ordinary 35 mm film. In the real focal
length photographing mode not selecting the pseudo focal length
photographing mode, the whole range of 24 mm long by 36 mm wide is printed
on a printing paper. In the trimming "1" mode, the range indicated by
A.sub.1 is printed; in the trimming "2" mode, the range indicated by
A.sub.2 is printed; and in the trimming "3" mode, the range indicated by
A.sub.3 is printed. The ratios of the print ranges on the film in the
trimming "1", "2" and "3" modes relative to the real focal length
photographing mode are set as approximately 1:1/.sqroot.2: 1/2:1/3.
Therefore, in the case where frames after photographing in those modes are
enlarged to the same size, there are printed the same ranges as those
photographed by lenses of the pseudo focal lengths shown in Table 1 below,
provided a focal length, f, of the photographing lens is assumed to be 35
mm.
TABLE 1
______________________________________
Photographing Mode
Focal Length
______________________________________
Normal Mode 35 mm
Trimming "1" Mode
50 mm
Trimming "2" Mode
70 mm
Trimming "3" Mode
105 mm
______________________________________
Referring now to FIG. 6, there are illustrated displays in the finder field
effected by means of a liquid crystal display LCD.sub.2. In the liquid
crystal display LCD.sub.2 there are provided four kinds of frames F.sub.0,
F.sub.1, F.sub.2 and F.sub.3 each corresponding to the printing ranges of
the real focal length photographing mode and trimming "1", "2" and "3"
modes respectively. Any one of these frames is displayed selectively
according to a set state of the trimming setting button 8. More
particularly, in the finder field, the frame F.sub.0 is displayed in the
real focal length photographing mode; F.sub.1 is displayed in the trimming
"1" mode; F.sub.2 is displayed in the trimming "2" mode; and F.sub.3
displayed is in the trimming "3" mode and the close-up mode.
Now, with reference to FIG. 7, the relation between the range photographed
by a photographic lens 20 and printed, and a light measuring range of a
light measuring system disposed in the interior of the light measuring
window 22, will be explained. In FIG. 7, in the real focal length
photographing mode, the range of B.sub.1 is photographed by the
photographic lens 20 and printed. In the trimming "3" mode of the smallest
printing range, the range of B.sub.2 is printed. It is assumed that the
angle of the field of view of the photographic lens 20 relative to the
smallest printing range B.sub.2 is .alpha.. On the other hand, behind the
light measuring window 22 is disposed a light measuring optical system
comprising a light measuring lens L.sub.5, a filter F and a light
receiving element 28. If its angle of the field of view is .alpha., the
relation thereof to .beta. is .alpha..gtoreq..beta.. Under this
construction, a light measuring range is always positioned within the
range to be printed, whereby a light measuring information always
corresponding to the range to be printed can be obtained accurately even
if the pseudo focal length photographing mode is set.
Referring now to FIG. 8, there are illustrated display modes of the liquid
crystal display LCD.sub.1 shown in FIG. 1. Although all the display
elements are indicated in FIG. 8, this does not actually occur. The marks
M.sub.1, M.sub.2 and M.sub.3 denote display elements which represent set
modes of photographing of the camera. In the real focal length
photographing mode, only the display element M.sub.1 is indicated. When
any one of the trimming modes "1", "2"and "3" is selected by operation of
the trimming setting button 8, only the display element M.sub.2 is
indicated. On the other hand, upon selection of the close-up mode, only
the display element M.sub.3 is indicated.
The marks D.sub.1, D.sub.2, D.sub.3, D.sub.4 and D.sub.5 represent display
elements for indicating printing ranges according to photographing modes.
In the real focal length photographing mode or normal photographing mode,
the display element D.sub.1 which shows the broadest printing range is
indicated. In the case of the pseudo focal length photographing mode, any
one of the display elements D.sub.2, D.sub.3 and D.sub.4 is indicated
selectively according to the trimming "1", "2" or "3" mode selected,
together with the display element D.sub.1. For example, in the trimming
"1" mode which is of the broadest printing range in the pseudo focal
length photographing mode, the display elements D.sub.1 and D.sub.2 are
indicated; in the trimming "2" mode, the display elements D.sub.1 and
D.sub.3 are indicated; and in the trimming "3" mode, the display elements
D.sub.1 and D.sub.4 are indicated. Further, in the close-up photographing
mode, the display element D.sub.5 is indicated.
The mark DA represents a display element for indicating date data printed.
The date data is not printed when its printing mode is not selected. The
display element DA may be so constructed as to indicate a date even where
printing of date data is not selected. The mark FC represents a display
element for indicating the number of frames photographed. Further, the
mark FE represents a display element for indicating a loaded state of the
film. In this way, various photographing modes, printed date, the number
of frames photographed, and the film loaded state, are indicated by the
liquid crystal display LCD.sub.1.
For example, FIG. 9 shows a display mode of the liquid crystal display
LCD.sub.1 in which the trimming "2" mode has been selected whereby the
display elements M.sub.2, D.sub.1 and D.sub.3 are indicated; data
corresponding to "July 25, 1985" is printed as date data; "24" is
indicated as the number of frames photographed; and a normal loaded state
of the film is indicated.
Referring now to FIG. 10, there is illustrated the camera body 2 as viewed
from the back, with a back lid thereof open. In FIG. 10, a spool chamber
2a for housing a spool 28 therein is provided in the camera body 2 in a
right-hand position in the figure, while in a left-hand position in the
figure there is provided a patrone chamber 2b for loading therein of a
patrone. Consequently, the film when wound up is moved from the left to
the right in the figure. Numeral 2c denotes a frame provided in a position
corresponding to the film, and at the rightmost end thereof is disposed a
code printing unit 30 for printing various photographic data as codes in
the film.
As shown in the enlarged view of FIG. 11, the code printing unit 30 has
seventeen optical fibers 30a one ends of which are arranged longitudinally
in the figure in an opposed relation to the emulsion surface of the film.
The other ends of these many optical fibers 30a are opposed to seventeen
light emitting diodes 32a which are fixed to a light emitting diode
substrate 32, as shown in FIG. 12 which is an enlarged sectional view of
the code printing unit 30.
FIG. 13 is an enlarged transverse sectional view of the code printing unit
30 and its vicinity, in which the mark FI represents a film loaded and
wound up. The film FI is held in a predetermined position of the frame 2c
under pressure by means of a pressure plate 40 which is given an
appropriate pressure by a pressure plate spring 38, the spring 38 being
fixed with pin 36 to a back lid 34 of the camera. The code printing unit
30 is fixed to the camera body and a light shielding tube 42, and on its
face opposed to an optical axis of the photographic lens there is provided
a light shielding plate 44. The light emitting diodes 32a are connected
through a flexible board PB to a later-described light emitting diode
driving circuit LEDR which functions to control ON-OFF of the light
emitting diodes 32a, thereby setting a code to be printed on the film.
Consequently, a code corresponding to each frame is printed on the
rightmost end of the frame when viewed from the back of the film, as shown
in FIG. 14. More specifically, code CO.sub.1 corresponds to frame
FI.sub.1, code CO.sub.2 to frame FI.sub.2 and code CO.sub.3 to frame
FI.sub.3. The mark CR in FIG. 14 represents the range in which code is
read; the right-hand side in the figure is the fore end side of the film,
while the left-hand side is the patrone side.
For each frame of the film, each code is constituted by a 17-bit digital
signal. Data represented by these bits will now be explained with
reference to FIG. 15. FIG. 15 is a rear view of the film photographed,
like FIG. 14, in which the right-hand side is the fore end side of the
film. The 17-bit code comprises, successively from above in the figure, a
3-bit trimming information code Ct, a 1-bit date print permission or not
permission information code Cs, a 4-bit year information code Cy, a 4-bit
month information code Cm and a 5-bit day information code Cd. The
trimming information code Ct will now be explained in detail. If the bits
of this code Ct are assumed to be b.sub.1, b.sub.2 and b.sub.3
successively from above in the figure, the relation between a set
photographing condition and those bit signals is as shown in Table 2
below.
TABLE 2
______________________________________
Photographing Mode
b.sub.1 b.sub.2
b.sub.3
______________________________________
Normal Mode 0 0 0
Trimming "1" Mode
0 0 1
Trimming "2" Mode
0 1 0
Trimming "3" Mode
1 0 0
Close-up Mode 1 0 0
______________________________________
In the numeral columns of the above table, "1" indicates that the
corresponding light emitting diode of that bit is turned ON, while "0"
indicates turning OFF thereof.
The date print permission or not permission information code Cs becomes "1"
in the case of printing a date and "0" when a date is not printed. As to
the year information code Cy, month information code Cm and day
information code Cd, data of year, month and day are converted to binary
digits.
The following description is now provided about the electrical circuit in
the camera of this embodiment, using the circuit diagram of FIG. 16. In
FIG. 16, the mark SW.sub.1 denotes a light measuring switch which is
closed by the first-stage depression of the shutter release button 4 shown
in FIG. 1; SW.sub.2 denotes a release switch which is closed by depression
up to the second stage of the button 4; SW.sub.3 denotes a key switch
which is opened and closed in interlock with the trimming setting button 8
shown in FIG. 1; SW.sub.4 denotes a winding switch which is closed in
response to shutter release and opened upon completion of the film
winding; SW.sub.5 denotes a back lid switch which is opened upon closing
of the back lid 34 of the camera and opened upon opening of the same lid;
SW.sub.6 denotes a film sensing switch which is opened when the film is
loaded and wound up and is closed when the film is not loaded; SW.sub.7
denotes a count switch which is closed at the beginning of the shutter
release operation and opened upon completion of charge of the shutter; and
SW.sub.8 denotes a date print selection switch which is closed when a date
printing mode is selected and is opened when date printing mode is not
selected.
The switches SW.sub.1 to SW.sub.4, which are starting switches, are
connected to an interruption terminal INT of a controlling microcomputer
CMC through a NAND gate NA and also connected directly to input terminals
PI.sub.1, PI.sub.2, PI.sub.3 and PI.sub.4 of the controlling microcomputer
CMC. Interruption to the controlling microcomputer CMC is caused by the
positive edge of input to the interruption terminal INT. The switch
SW.sub.5 is connected to an input terminal of the NAND gate NA through a
differential circuit comprising a capacitor C.sub.2 and a resistor
R.sub.3. This is for setting the count value of the film counter to "0"
when the back lid of the camera is opened. Further, the switches SW.sub.5
to SW.sub.7 are connected to input terminals PI.sub.5, PI.sub.6 and
PI.sub.8, respectively, of the controlling microcomputer CMC. The switches
SW.sub.1 to SW.sub.7 are connected to a power terminal E.sub.1 through
pull-up resistors, respectively.
The mark E represents a power battery of the camera, having an output which
is connected to an input terminal of the controlling microcomputer CMC
through a stabilizing circuit comprising a diode D.sub.2 and a capacitor
C.sub.3. To the circuits which are liable to cause erroneous action due to
the change in voltage supplied thereto, electric power is fed from the
power terminal E.sub.1 stabilized by the stabilizing circuit, while to the
other circuits the electric power is fed directly from the power battery
E.
The mark FL represents a flash circuit including a flash tube for flash
photography and a control circuit for the flash tube, in which a booster
circuit for applying a high voltage to a main capacitor is operated with a
signal provided from an output terminal PO.sub.7 of the controlling
microcomputer CMC, and flashing is started with a signal provided from an
output terminal PO.sub.8. Further, when the charging voltage for the main
capacitor reaches a predetermined value, a charge completion signal is fed
to the controlling microcomputer CMC through the input terminal PI.sub.7.
The mark MD denotes a motor driving circuit which controls the film winding
motor M. With a signal provided from an output terminal PO.sub.5 of the
controlling microcomputer CMC, the motor M is driven to wind up the film,
and its drive is braked with a signal provided from an output terminal
PO.sub.6.
The mark CAS denotes film sensitivity reading switches which read data on
film sensitivity prestored in the film patrone loaded into the camera and
which are opened or closed according to the read data. The film
sensitivity data as digital data read by each switch CAS is converted to
an analog signal by means of a D/A converter (D/A). This analog film
sensitivity signal is fed to a light measuring circuit comprising a photo
diode PD, an operational amplifier OP and a logarithmic compressing diode
D.sub.1, in which it is added to a light measuring signal. The output of
this light measuring circuit is therefore a light measuring signal with
the film sensitivity signal added thereto. This signal is applied to the
base of a transistor TR.sub.1 through a buffer B and is subjected to a
logarithmic expanding in a logarithmic expanding circuit comprising the
transistor TR.sub.1 and a capacitor C.sub.1. The charging voltage for the
capacitor C.sub.1 is compared with a predetermined voltage E.sub.2 by
means of a comparator CN, and when it drops below E.sub.2, a transistor
TR.sub.5 becomes non-conducting and a shutter magnet SMG is de-energized
to close the shutter. Transistors TR.sub.2 and TR.sub.3 are controlled by
an output terminal PO.sub.4 of the controlling microcomputer CMC, and they
are for controlling the timing of the energizing of the shutter magnet SMG
and the logarithmic expanding. Further, a transistor TR.sub.4 is
controlled by an output terminal PO.sub.3 of the controlling microcomputer
CMC, and it is for charging the capacitor C.sub.1 rapidly to change a
maximum aperture value and to change a longest shutter speed according to
the photographing mode selected, as will be described later.
The output of the light measuring circuit, which is a light measuring
signal with the film sensitivity signal added thereto, is fed to an A/D
converter (A/D) and converted to a digital signal, which in turn is fed to
the controlling microcomputer CMC through input terminal PIAD. Further,
the digital signal according to film sensitivity provided from each switch
CAS is fed to the controlling microcomputer CMC from input terminal PIDX
of the microcomputer and also fed to a later-described display
microcomputer DMC.
The display microcomputer DMC controls the display of the liquid crystal
display LCD.sub.1 on the upper surface of the camera and that of the
liquid crystal display LCD.sub.2 in the finder, and it also controls the
code printed in the film. It is supplied with the electric power through
the power terminal E.sub.1, and the date print selection switch SW.sub.8
is connected to an input terminal pi.sub.1 of the display microcomputer
DMC. The display microcomputer DMC is constructed so that interruption is
caused by a signal applied to an interruption terminal int.sub.1 or
int.sub.2 which are connected to output terminals PO.sub.11 and PO.sub.12,
respectively, of the controlling microcomputer CMC. Interruption to the
interruption terminal int.sub.1 is caused when changing the display of the
liquid crystal displays LCD.sub.1 and LCD.sub.2, while interruption is
caused to the interruption terminal int.sub.2 at the time of printing code
on the film.
Further, signals concerning photographing modes are each provided from the
controlling microcomputer CMC to the display microcomputer DMC through
output terminal POD and input terminal piD. Moreover, as mentioned above,
signals on film sensitivity are each fed to input terminal piDX. Further,
a clock circuit for determining a date to be printed on the film is
incorporated in the display microcomputer DMC.
The display microcomputer DMC controls the liquid crystal display LCD.sub.1
on the upper surface of the camera and the liquid crystal display
LCD.sub.2 in the finder, through a liquid crystal drive circuit LCDR.
Therefore, photographing mode signal, date signal, film presence-absence
signal, film winding-related signal, and date print permission or not
permission signal, are transmitted from the display microcomputer DMC to
the liquid crystal drive circuit LCDR, which in turn latches those data to
be displayed. Further, the display microcomputer DMC turns ON or OFF the
light emitting diodes 32a for code printing, through a light emitting
diode driving circuit LEDR. The light emitting time of each light emitting
diode 32a is varied according to the film sensitivity signal fed to the
input terminal piDX.
The mark AF represents an automatic focusing circuit which measures the
distance up to an object automatically and adjusts the focus position of
the photographing lens according to the results of the measurement. The
automatic focusing circuit AF, which is supplied with electric power from
the power terminal E.sub.1, starts its automatic focusing operation upon
receipt of a signal from output terminal PO.sub.1 of the controlling
microcomputer CMC. The distance to the object thus detected is fed as a
4-bit digital signal to the controlling microcomputer CMC from input
terminal PIAF. Output terminal PO.sub.2 of the microcomputer CMC becomes
"H" when the camera is set to the close-up mode, and all the bits of the
distance signal related to the distance to the object are made "H" to let
the distance signal indicate the closest distance forcibly. At this time,
therefore, the photographic lens is set in the closest state. The mark LMG
represents a lens stopping magnet which is de-energized upon coincidence
of the distance signal with a signal indicative of the shifting amount of
the lens to stop the shifting of the photographing lens.
The RMG represents a release magnet for starting the shifting of the lens.
The release magnet RMG is controlled by a signal from output terminal
PO.sub.10 of the controlling microcomputer CMC. After energizing for a
certain period of time, it is de-energized to disengage the photographic
lens, thereby allowing the shifting of the photographing lens to start.
A more detailed construction of the automatic focusing circuit AF is shown
in FIG. 17, in which the mark DD represents a distance detecting circuit
for measuring the distance up to an object, the operation of the circuit
DD being started by a signal from output terminal PO.sub.1 of the
controlling microcomputer CMC. Its optical system is shown in FIG. 4. The
distance to the object detected by the distance detecting circuit DD is
output as a 4-bit digital signal, and the signal of each bit are fed to
comparator CON through an OR circuit and also applied to the controlling
microcomputer CMC through input terminal PIAF. To all the other input
terminals of the OR circuit are connected the output terminal PO.sub.2 of
the microcomputer CMC. Therefore, when the close-up mode is selected, all
the bits of the distance signal fed to the comparator CON are "H",
representing the closest position, independently of the output signal from
the distance detecting circuit DD.
On the other hand, the mark EC represents an encoder which provides pulses
according to the shifting amount of the photographic lens. The pulses
provided from the encoder EC are counted by a counter CU which is reset by
a signal from the output terminal PO.sub.1 of the controlling
microcomputer CMC. This count value is compared with the distance signal
by means of the comparator CON, which provides an output signal upon
coincidence of both signals to de-energize the lens stop magnet LMG,
thereby stopping the shifting of the photographic lens in the position
corresponding to the distance signal.
In the camera of this embodiment, when a frame is photographed in the
pseudo focal length photographing mode, that is, the trimming "1", "2" or
"3" mode or the close-up mode, the enlarging ratio of the frame becomes
larger in printing if the frame is printed to the same size as that of a
frame photographed in the real focal length photographing mode.
Consequently, blur and flare which have not been conspicuous in the real
focal length photographing mode become conspicuous. To avoid this, in the
camera of this embodiment, the maximum aperture value (i.e. maximum
F-number) and the longest (maximum) shutter speed are varied according to
the printing size in the frame. Therefore, if the pseudo focal length
photographing mode is selected, the depth of field is extended and the
longest shutter speed (the maximum exposure time) is limited for avoiding
the blurring of the object image on the film. Here, the larger the maximum
aperture value, the shorter the maximum shutter speed, since the shutter
is operated as an aperture diaphragm in this embodiment. But the present
invention is not limited to this construction. It may be constructed so
that only the maximum aperture value or only the shutter speed limit is
changed according to the selected photographing mode.
Table 3 below shows photographing modes as well as maximum aperture values
(maximum F-number) and lower limit values of the shutter speed in this
embodiment.
TABLE 3
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Photographing Mode
Avmax Tvmin
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Normal Mode 2.8 1/30
Trimming "1" Mode
2.8 1/30
Trimming "2" Mode
4 1/60
Trimming "3" Mode
5.6 1/250
Close-up Mode 16 1/1000
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In the above table, "Avmax" and "Tvmin" represent maximum aperture value
and longest limit value of the shutter speed, respectively. This is
illustrated in FIG. 18, in which the vertical axis represents aperture
value and the horizontal axis represents the time counted from the opening
of the shutter. In the real focal length photographing mode or the
trimming "1" mode, it is possible to open the aperture and to lengthen the
shutter speed up to the combination of aperture value (F-number) 2.8 and
shutter speed 1/30, as indicated by A. In the trimming "3" mode, the
aperture can be opened and the shutter speed can be lengthened up to the
combination of aperture value (F-number) 5.6 and shutter speed 1/60, as
indicated by B. Further, in the close-up mode, only the combination of
aperture value (F-number) 16 and shutter speed 1/1000 can be set. Where an
appropriate exposure is not obtained under such combinations of limited
apertures and shutter speeds, flashing is made automatically. As shown in
the lower time chart of FIG. 18, where the combination of aperture value
(F-number) 5.6 and shutter speed 1/60 causes under-exposure for example in
the trimming "2" mode, a signal is issued from the output terminal PO.sub.
8 of the controlling microcomputer CMC at a time point T.sub.1 at which
the shutter also serving as aperture is opened up to an aperture value
(F-number) of 8 calculated in accordance with the distance signal provided
from the automatic focusing circuit AF, whereby flashing is started. And
at a time point T.sub.2 at which the shutter is opened up to an aperture
value (F-number) of 5.6, a signal is issued from the output terminal
PO.sub.4, whereby the shutter closing operation is started.
In this connection, an exposure value EV for change-over to flashing is
also changed according to the selected photographing mode. Table 4 shows
the relation between photographing modes and exposure values (assumed to
be Evc) for change-over to flashing.
TABLE 4
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Exposure Value for
Photographing Mode
Change-over
______________________________________
Normal Mode Ev 8
Trimming "1" Mode
Ev 8
Trimming "2" Mode
Ev 10
Trimming "3" Mode
Ev 12
Close-up Mode Ev 18
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If the subject brightness is Bv, film sensitivity Sv, aperture value Av and
shutter speed Tv in APEX calculation, the exposure value Ev (or Evc) is
defined as follows:
EV (or Evc)=Bv+Sv=Av+Tv
The relation between aperture value at the time of change-over to flashing
and shutter speed value is shown in FIG. 19, in which its vertical axis
represents aperture value and its horizontal axis represents shutter
speed. In the real focal length photographing mode and the trimming "1"
mode, flashing is not made at an exposure value Ev of 8 or more as
indicated by Da, while in the trimming "2" mode, flashing is not made only
at an exposure value Ev of 10 or more like Ea. Further, in the trimming
"3" mode, flashing is not made only at an exposure value Ev of 12 or more
like Fa, and in the close-up mode, flashing is made only at an exposure
value Ev of 18 or more (not shown). This is for minimizing the aperture to
make the depth of field large in the case where the enlarging ratio in
printing is large.
The operation of the controlling microcomputer CMC for controlling the
camera of this embodiment will now be explained with reference to FIGS.
20A, 20B and 20C which are a flow chart showing operations of the
controlling microcomputer CMC in the camera of this embodiment illustrated
in FIG. 16. In FIG. 20A, circuits are reset upon power ON reset caused by
loading of the battery, then in step S0 the input ports, the output ports
and memory of the controlling microcomputer CMC are all initialized. More
specifically, all the other output terminals than PO.sub.10 of the
microcomputer CMC are so initialized as to output "L", and the
photographing mode is initialized to the real focal length photographing
mode. Then, in step S1, each port and flag of the controlling
microcomputer CMC are initialized and in step S2 there is made an issue of
"H" signal at the output terminal PO.sub.7 of the same microcomputer,
whereby the booster circuit in the flash circuit FL is allowed to start
operation. Then, in step S3, an external interruption to the interruption
terminal INT of the controlling microcomputer CMC is permitted and in step
S4 the microcomputer assumes a state of normal stop.
Then, when an external interruption is caused to the interruption terminal
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