Argus C3 User manual

THE BUILT-IN SHUTTER
The escopements you hove studied so forore cleverly designcd
to fit into the cromped quorters oround the lens. A complox
problem in the design of ony shutter is proper use of ovoiloblc
spoce. And in most of the shutters exomined in previous lessons,
the shutter mechonism fits into o housing which olso serves os the
lens mount.
The ingenuityof thedesigners hos produced escopement geor
troins ond other poris thot ore curved to follow the shope of the
housing. Even the moin lever -- in lorger models of the Compur,
for exomple -- moy be o ringwhich fits oround the lens borrel io
toke best odvontoge of the existing spoce. Moin levers in mony
other shutters follow this circulor pottern, ond usuolly provide
for complete shutter operotion with o very minimum omount of
movement.
So ihe ports in the modulor shutters you've studied must be
smqll in orderto fit the ovoiloble spoce. Smoll ports require high
precision -- ond the shutter occurocy is frequently the result of
fine croftsmonship os well os good design.
NOTE: Shutters such os the Synchro-Compur 00-MXV
ond the Prontor SVS qre exomples of modulor shutters --
thot is, shutters mode byo single monufociurer which moy
be used on comeros of mony different mokes.
In controst to the modulor shutter, the BUILT-lN SHUTTER
is integrolwiththecomero itself -- ond, os such, is unique to the
porticulor comero in which it is used. Built-in shutters moy be
extremely simple -- such os you studied in the Kodok lnstomotic
ond Brownie Reflex comeros. Or, they moy be quite complex --
suchos the focol-plone shutters youwill exomine in future lessons.
The built-in shutter tokes odvonioge of the lorge omount of
spoce within the comero body. Since the ports ore not restricted
to the circulor confines oround the lens, they con be mode com-
porotively lorge, rugged, ond simple. Or, the ports moy remoin
smoll ond precise while the comero itself is scoled down io
pocket-size proporiions.
ln this lesson, you will exomine three voriotions of the
built-in leof-type shuiter. And you'll see how the shutfer blodes
moy be locoted either behind the lensor between the lens
elements -- even though the shutter blode driving ond timing
mechonisms ore spreod out behind the lens in the comero body.
2
i

The Argus C-3, Fig . 2, is o good exomple of o 35mm comero
using o built-in behind-the-lensshutter. ln theArgusC-3, olmost
o third of the volume of the comero body is used to house the
shutter mechonism. The result of the Argus design is o shutter
thot is inexpensive to monufocture, eosy to service, ond quite
dependoble -- three foctors which contributed to moking ihe
Argus C-3 one of the most populor 35mm comeros ever designed.
R ELEASE
BUTTON
RANGEF INDER
DISC -
SETT ING
LEVER
FILM WIND
KNOB
FIGURE 2
SPEED KNOB
*
ARGUS C-3
RANGEF INDER
WINDOW
VIEWF INDER
WINDOW
FIGURE 3FRONT PLATE POSITIONS
The Argus C-3 hos two controls in oddition to the setting
ever ond the releose button. One of these controls --the SPEED
KNOB--operotes o com to determine the omount of retord, Fig.3.
3

R ELEASE
BUTTON
COUNTER
DIAL
F ILM
WIND
KNOB
FIGURE 4
The other control permits "bulb" operotion -- iust turn the knurled
releose buiton from "l" (instontoneous)to "B" (bulb), Fig. 4.
Notice thot the speed knob, Fig. 3, contoins the number
colibrotions 4 rhrough 8. The porticulor Argus C-3 illusiroted is
colled the "Motchmoticr" o nome which refers to the unique
method or colibroting the shuiter speeds ond the f/stops. Other
Argus C-3 modeIs ore colibrofed in the conventionol frocfions of
o second. The numberson the Motchmqtic speed knob refer to the
fol lowing shutter speeds:
8 -- l/300 second
7 -- 1/125 second
6 -- l/60 second
5 -- l/30 second
4 -- 1/10 second.
REMOVING THE FRONT PLATE IN THE ARGUS C-3
The front plote ossemblies of the vorious Argus C-3 comeros
vory only slightly. ln the older models, the setting lever is held
by o setscrew. Just loosen the setscrew ond unscrew the setting
lever in o counterclockwise direction.
But the setting lever setscrew is eliminoted in the loter
models -- suchqs the comero illustroted. lnsteod, o JAM NUT --
locoted immedioiely under the setting lever, Fig. 5 -- holds the
setting lever in ploce. The setting lever post (on the moin lever,
os you'llsee in o moment) hos o left-hond threod. So moving
the setting lever counterclockwise to cock the shutter binds the
iom nut ond the setting lever more rightly ogoinst one onother
4
1

,ut"
JAM NUT
*J
FIGURE 5
Hold the newer-style setting lever stof ionory wif h your f ingers
ond turn the iom nut counterclockwise with o thin-heoded wrench
-- you ore now moving the iom nut owoy from the setting lever.
Then, unscrew the setting lever from its post by turning it in o
clockwise direction --ond, ofter removing the setting lever, turn
off the iom nut in the some direction.
CAUTION: Do not remove the Argus C-3 speed knob
during the froni plote d isossembly -- the speed knob remo ins
in ploce on the front plote. ln the Motchmotic, the
speed knob retoining screw is covered by the cemented
colibrotion plote. But in other models, the screw is
visible -- ond there's olwoys o temptotion to remove on
' exposed screw. The speed com -- which controls the
movement of the retord section -- is ottoched to the bock
side of the speed knob. So by removing the screw, you
lose the timing between the speed knob ond ihe speed
com. You con, however, see the properspeed com timing
in f igures 7 ond 8.
Five or six screws (the numberdepending on the model) reioin
the front plote to the comero body. These screws ore underneoth
the leotherette covering the front plote, os indicoted by the orrows
in figure 3. So corefully lift the leotherette ot the four corners
of the front plote with your bench knife -- iry to ovoid teoring
or shorply creosing the leotherette.
,w
';-"-.
5

Another screw is locoted ot the bottom center of the fronl
plote --os indicoted by the doshed orrow in figure 3. And, in
some models, there is o sixth screw odiocenf to the rongefinder
window. You con reoch the lower screw without completely re-
moving the leotherette --either lift the bottomof the leotherette
or cut the leotherette os indicoted by the doshed orrow, Fig. 3.
Moke your cut very corefully with the shorp point of your bench
knife -- when you loter recement the leotherette, the cut will
be olmosf undetectoble.
lf the sixth retoining screw is used, you con cut the leotherette
by the rongefinder window, Fig. 6. Remove oll of the flot-
heoded screwswhich hold the frontplote. Then, corefully lift off
the front plote -- be coreful youdon'tdropouttheCAM
FOLLOWER which remoins wiih the front plote, Fig. 7.
FRONT'
PLATE
SCREW
FIGURE 6
CAUTION: The front
once you've removed
lens to prevent loss or
covity to the right of
lens for theeyepiece moy be loose
the front plote. lf so, lift out the
domoge --the lens sits in the round
the rongefinder ossembly, Fig. 10.
Figure 7 shows the inside of the.front plote--here, you con
see the speed com ond the com follower. The pin on the com
follower fits into the hole in the BELL CRANK (in the lower right-
hond corner of the comero body, Fig. 9). The bell cronk is port
of the linkoge between the speed com ond the speedsescopement,
olso pointed out in figure 9.
6
J

SPEED CAM
CAM
FOLLOWER
PIN ON
CAM
FOLLOWER
FIGURE 7
SHUTTER SET TO l/300 SECOND ("8" ON MATCHMATTC)
i$rylr
FIGURE 8
SHUTTER SET TO l/10 SECOND ("4" ON MATCHMATIC)
You'll notice thot thecomfol lower is otits highest
position when the comero is set to thefostest shutterspeed (l/300
second), Fig.7. And the com fol lower is ot its lowest position
when the shutter is set to the slowest shutterspeed (lrll0second),
Fig. 8.
,$

OPERATION OF THE ARGUS C-3 SHUTTER
The moin lever in the Argus
The SHUTTLECOCK ond o lons
SHUTTLECOCK RIBBON -- con
tension-type mo inspring.
C-3 is o multiple com, Fig. 9.
phosphor bronze ribbon -- the
nect the moin levertothe
MAINSPRING
SHI.JTTLECOCK
SHUTTLECOCK
RIBBON
MAIN LEVER
ESCAPEMENT
BELL CRANK
FIGURE' .
To cock the shutter, rotote the moin lever in o counterclock-
wise direction with your finger -- os shown in figure 10. The
moin lever is then lotched in the cocked position bythe lowerend
of the RELEASE PLUNGER, Fis. I l.
FRONT LENS FOR
EYEPIECE SITS IN
THIS CAVITY
COCKING
ROTATION
FIGURE 1O
Depressing the releose button pushes the reIeose plungerdown
to free the moin lever. Now, the moinspring pulls the shuttlecock
from left to right. cousing the moin lever to rotote ino clockwise
8

BELL
CRANK
SPRING
LOWER
END OF
RELEASE
PLUNGER
RETARD
LEVER
WIRE LINK
FIGURE 11 SHUTTER COCKED
direction. The shuttlecock ossembly, during its releose trovel,
contocts o lug on the blode operoting ring to open the shutier
blodes -- you'll be oble tosee the oction of theshuttlecockmore
cleorly ofter we remove the shutter blode ossembly. A spring on
the blode operoting ring, not yet visible, then closes the shutter
blodes.
Since you've removed the front plote -- ond, olong with it,
the speed comond the com follower--the shutternowdeliversthe
fostest speed (lrl300 second). The reoson is thqt the bell cronk
spring, Fig. ll, holdsthebell cronkoll thewoy inthe
counterclockwise direction .
Setting slower shutter speeds pushes the bell cronk in o
clockwise direction -- the speed com pushes the com follower
down, ond the com follower in turn rototes the bell cronk .
Notice in figure ll thot o long WIRE LINK connects the bell
cronk fo the RETARD LEVER in the speeds escopement.
ln its present position -- V\OO second -- the retord lever
holds the first geor segmenf (in the speeds escopement)owoy from'
the lobeot the bottomof the moin lever. But os youselecf slower
speeds, the bell cronk pulls the retord lever owoy from the
first geor segmenf . The first geor segment then turns clockwise,
under iis own spring tension, os simuloted in figure 12 -- now,
the pin (on the first geor segment) is in the position to intercept
the lobe (on the moin lever) during the releose cycle.
So the posifion of the bell cronk determines the position
of the retord. lever -- ond the retord lever decides how for the
9

LOWER
LOBE
ON
MAIN
LEVER
PIN ON
F IRST GEAR
SEGMENT
FIGURE 12
first geor segment rototes in o clockwise direction. The foriher
the first geor segment moves clockwise, the longer it remoins in
contoct with the moin lever lobe during the releose cycle -- ond
the slower the resulting shutter speed.
The bell cronk pivots onon eccentric beoring which provides
on odiustmentpoint fortheshutter speeds. You'll odiust the shut-
ter speeds ofter replocing the fronf plote -- o hole through the
front plote ollows you to reoch the eccentric beoring, os you'll
see o little loter.
You con see thot the ArgusC-3 retord system is quite unlike
onything exomined in previous sysfems. But the most unusuol port
of the whole design is the time ot which theretord is introduced.
ln othershutters werve discussed, the blodesopen fully before the
speeds escopement slows down the moin lever -- the escopement
then holds the blodes fully open for the required length of time.
Yet in theArgus C-3, the moin leverstrikes thefirst geor segment
iust os the blodesstort toopen. So the retord is introducedduring
the blode-opening time --the slower the shutter speed, the more
slowly the blodes open.
The position of the pin on the firstgeorsegmentot theslowest
shutterspeed is criticol -- coreful observotion now will help you
inodiusting theescopemenf during reossembly. Thot is, thespeeds
escopement hos o sliding odIustment -- ofter loosening the two
screws shown in f igure I3, you con slide the complete escopement
to odiust its position. Referring to figure 13, here's the timing
you should note:
10

With the first geor segment in the slowest-speed position
ond the moin lever in the cocked position, the lobe on
the moin lever should contoct the pin on the first geor ,,
segment -- but, of the some time, comPlete rototion "t '(-
the moin lever must be possible without interference from r
the first geor segment. ,f
a uo-
FIGURE 13
To obtoin "bulb" oction, rotote the releose button until its
"B" colibrotion oligns wiih the index dot on the comero body.
Turning the releose button to "B" rototes the releose plunger to
the poiition shown in figure 14. Now, when you re.leo-se the
shutier, the blqdesopen to the full-open position --butthe flotted
SPEEDS
ESCAPEMENT
SCREWS
PIN ON
F IRSI
GEAR
SEGMENI
END OF
RELEASE
PLUNGER
FrcuRE 14 SHUTTER COCKED, SET TO "BULB"
11