Table of Contents
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I.
Shutter Model 384
a.
AJIer"'"'
Wheel
Operation
L The only additional mechanical information
needed is aperture wheel utilization. There are
eight
(8)
holes (apertures) in the wheel,
arrant
ed in sets of two (2), one large. one small; each
set is. used for one of four different film speeds.
Manual rotation of the aperture wheel positions.
-
one of the
:sets
of openings in front of the shut
ter
~
the other aperture of the set
is
selected
by
the scene selector slider (Fig. 2-4),. A detent
block and spring stops the aperture wbeeJ
after each turn, and a readout actuator and
actuator detent spring. secures the wheel at
each position.
-
-
ACTUATOR
OETENT
OETENT
BLOCt(
-
-
-
-
-
SCENE
SELECTOR
SUCER
APERTURE
WHEEL
FIG.2-4 APERTURE WHEEL OPERATION
-
:;:, There are four (4) exposure time circuits when
-
fhe same light level is used in testing. Under
actual use conditions. the
photocen
is
an
in~
finitely varying resisrance. and the range of
-
exposure times
is
unlimited. Connection to
each of the Resistor-CapacitoT
(Re)
time
cir
cuits, is made by a four (4) position switch
Tot('Jf (S3) molded into the reverse of the aper
-
ture wheel. Fig. 2-5
-
11
COMMON
3. As the wheel
is
rotated throuylt the various
aperture positions. the capacitor ,"witch rotor
connects the contacts on one
of
four
(4)
com
binations. The combination connected
through the rotor, selects the
RC
circuit which
will
be
used in shutter timing.
,lbe
values
of
the capacitors
are
diff~rent.
their
charging rates vary; the photoceU resistance
varies with the light falling on it: and. finaUy.
lixed resistance values are selected according
to
RC
timing
needs~
'The
combination of these
factors determines exposure times of the shutters.
b. _ _IOI'
I, The Scene Selector slider selects one of the two
(2l available anertures at each setting of the
wheel.
lbe
smaller aperture of ee:ch set of two
is used forth. fastest films IASA3000 B & WI.
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