Nikon BC-7 User manual

Nikon
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2
NIKON FLASH UNIT BC-7 is the compact and light weight
and yet quite powerful flash unit, to fit the Nikon F camera.
FIG. 1
_I

FEATURES
The flash unit BC-7 makes electrical connection with the flash syn-
chronization terminal in the Nikon F, Nikon F Photomic, Photomic - T,
TN or FTN camera, only by fitting into the camera accessory shoe,
eliminating the need for connecting cord_
• It is provided with a three -way socket which permits the use of three
types of flash bulbs: S. C. bayonet base, miniature base (M2)
or AG-l (A ll-Glass ).
• When you insert a flash bulb into the socket, it charges the capacitor
instantaneously and automatically, thus avoiding drain of the battery.
• It is provided with test circuits for checking each flash bulb, charg-
ing of the capacitor, the synchronization circuit as well as connection
of the flash unit.
• The synchronization cord socket, provided besides, permits the US\!
of the unit for extension flash.
• The collapsible, fan-fold ty pe reflector a ffords compactness a nd great
facility for carrying about the unit.
3

"
SPECIFICATIONS
Flash bulb socket
Three-way type socket permits use of anyone of the following three
types of flash bulbs:
S_ Co Bayonet base
Miniature base (M 2)
AG-l (A ll -G las s)
Illuminating angle
Approx_ 65°
Tilt-back angle of the reflector (for bounce flash)
Click-stops at 0° (for general use), 30°, 60°, 90° and 120°
Power source
B-C type : The capacitor is automatica ll y charged by fitting a bulb
to the socket.
Battery to be used
15 V laminated dry battery (Eveready No_ 504 or the similar)
(This type battery is available on the market.)

Testing system
Checks the synchronization circuit, connection of the fl ash bulb and
charg i ng c ir cuit.
Connection to the camera
Direct, cord l ess connection to the fl ash terminal on the camera ac·
cessory shoe.
Synchronization cord socket
P. C. type socket is provided for connecting the cord fClr extension
flash.
Weight
Approx. 180 g (w ithout la minated battery )
5

NOMENCLATURE
FIG. 2 Thr ee ·way so ck et FIG. 3
s ho e Cordless contact
6

FIG. 4
Exposure
Calc
ul ator
Ejector
Char
ge testing button (white)
(to check for the corr
ec t
con nection of fl as h bulb)
7

8
LOADING THE BATTERY
Pushing downwards the rear cover
clip on the back of the unit, open
, the cover.
Insert th e lamina t ed battery 15V
(Eveready No. 504 or the simi.
l ar), into the unit, according to
the plus and minus symbo ls.
Loop the vinyl tape under the
battery to facilitate the removal
of the battery.
FITTING TO THE CAMERA
Slide in the foot of the flash unit
from the rear of the camera into
the - camera accessory shoe as far
as it will go, whe re the terminal
on the flash unit comes int o con·
t act secure ly wi th that on the
rear of the accessory shoe.
To detach th e unit, reverse the
above procedure.
It 'is convenient to fold up the reo
flector in mounting or di smount·
ing the flash unit. (Fig . 5)

I FIG. 5
9

10
CHECKING SYNCHRONIZATION CIRCUIT
Checking of the cir cuit shou ld be done before the camera is loaded
with the film.
1. Ti lt upwards the reflector, attached to the camera, to the position
for bounce flash as i ll ustrated. (Fig. 6 (a))
2.
Keep pushing the red button for 3-4 seconds.
Whi le pushing this button, depress the shutter release button on
the camera . (Fig. 6 (b))
If the inside test lamp glows instantly (visible through the back
cover of the flash unit), it indicates that the circuit is functioning
properly .
Note: If the test lamp does not light in this test, check the following:
• I
mperfect con t act of the terminals
• Drain of the battery
• Trouble in the capacitor
• Disconnection of the test lamp. etc .

FIG. 6 <a)
FIG. 6 <b)
II

12
OPENING THE REFLEC TOR
Spread out the ref l ector. When
fu ll y opened, the ends of the
ref l ector are to be hooked up
toge t her.
For closing, re l ease the ends of
the ref l ector.
FIG. 7

ATTACHING THE FLASH BULB
Push the bulb into the socket on the flash unit so that it is held se·
curely .
To remove the bulb from the unit. push the bulb ejector button on the
head. The bulb will drop off.
CHECKING THE FLASH BULB
FIG. 8 Attach a flash bulb by' inserting
its base in
to the socket.
A
few seconds afterward. push
the button.
If the inside test lamp glows
briefly. t
hi s indicates that the
flash bulb is good and
th e capa c·
itor has been charg ed.
13

14
USE OF SYNCHRONIZATION SELECTOR ON THE NIKON F
For positive sy nchronization, set the sy nch selector according to the
~lash bulb and shutter speed used. See the table on next page .
Lift up the milled selector ring on the outer edge until the desired
colored
dot and / or figure appears on the selector window adjacent to
the dial; then drop the ring into place.
In
case of Nikon Pho t omic T, TN or FTN camera, it is necessary to
once remove the finder from the camera beforehand .

Flash Bu lb
Shutler Speed
Make
Class Type
1000 \500 \250 \125
30 \15\8\4\2\ 1 \ B
C.E. Sylvania
60
FP
No.6 FP 26
•
Bayon et
No. 6B FP 26B
Green
No.5
Press 25 --
:1 . • Bayonet
No.5B Pre~s '258 --
M . - Red
Mi niature M 5 M 3 -- - - O F
(M2) M
5B M 3B
----White
-
Miniature M 2 M2
- - - - -
(M2) M
2B M 2B
- - - - -
MF
AC- l
AC- l -- - - -
AC- l
AC- IB
AC- IB --- - -
15

16
HOW TO USE THE EXPOSURE CALCULATOR
The calculator provided on the flash unit BC-7 is primarily designed
to facilitate the use of a fl ash bu lb for focal-pl ane shutter.
Set the film speed (ASA ) graduated on the upper revolving dial to
the shutter speed graduated on the inside fixed dial, and the correct
exposure will be obtained by reading the lens aperture on t he fixed
dial or the subject distance on the revo l ving dia l, either being brought
into coincidence with each other.

Example 1.
Flash bulb : G.E. No. 6
or
Sylvania FP 26
Shutter speed: 1/125 sec.
(
Turn the synch selector dial
on
the Nikon F until the green
dot appears in the window.)
Speed of
film: ASA 160
Distance to
the subject: 10 ft.
1.
Turn the revolving dial to set
the ASA figure 160 for black.
and.white film (in black) to
the shutter speed figure 125.
2. The correct exposure will be
obtained
with an aperture of
about f/ 11 at the distance of
10 ft.
FIG. 9
17

18
Example 2.
Flash bulb : G.E. No. 6B or
Sylvania FP 26B
Shutter speed: 1/ 125 sec.
(Turn the synch selector dial
on
the camera until the green
dot appears.)
Speed of film : ASA 64
Distance to the subject: 10 ft .
1. Turn the revolving dial to set
the ASA figure 64 for color
film (
ia red ) to ' the &hutter
speed figure 125.
2. The correct exposure will be
obtained with an aperture of
about halfway between f/ 4 and
f/ 5.6 at the distance of 10 ft.
FIG. 10

Example 3.
Flash bulb:
Shutter speed :
G.E.
AG-1 or
Sylvania AG-1
1/ 30 sec.
(T).lrn the synch se l ector dial on
tlie Nikon F until the white dot
and F appe; ars in the window.)
Speed of film: ASA 160
Distance .to the subject: 10 ft.
1. Turn the revolving dial to set
the ASA figure 160 for black·
and-white film(in black) to the
white dot (for AG- 1).
2. The correct exposure will be
obtained with an aperture of
about fi ll at the distance of
10 ft.
FIG. 11
19

20
EXPOSURE DETERMINATION BY GUIDE NUMBERS
The maker of each type flash bulb publishes the guide numbers, which
are convenient ly used to determine the correct exposure. Divide the
guide number (GN) by the subject distance (D) or the f.number (A),
and you will be given the f·number or the subject distance to be set,
respectively. GN
D
or A A or D
However,
since such guide numbers are generally given on the basis
of a fixed·type, l
arge.diameter ref l ector with a polished reflecting
surface, and not of a fan.fold, wide. ang le type reflector with a light
scattering reflecting su rf ace, such as of the BC-7 flash unit, it is nec·
essary to increase the exposure by opening the aperture about a half
stop l arger than the value obtained by the above ca l cu lation.
Example 1.
Flash bulb :
Shutter speed:
Speed of film :
Guide
number:
Subject Distance :
200
=13 3
15 .
G.E. M2
or Sylvania M2
1/ 30 sec. ( Turn the synch selector dial on
the Nikon F camera until a white dot and F
appear in the window.)
ASA 125 •
About 200
15 ft.
Then, open the aperture of lens a half stop.
l
arger than f/13.3, that is, about fill.