Flashes & lighting
Nikon BC-7 Flashbulb User manual
User manual for Nikon BC-7 Flashbulb. 20 pages in English. Read the original PDF, download or print a copy without registration.
20 pagesEnglish3.7 MB PDF
Loading your manual…Open PDF directly
Document details
- Brand
- Nikon
- Model / document
- Nikon BC-7 Flashbulb
- Document type
- User manual
- Language
- English
- Pages
- 20
- File size
- 3.7 MB
- Category
- Flashes & lighting
- Document date
- Not specified in catalog
Search available document text
Find a term, then jump to its page in the original PDF. Image-only pages may not be searchable; check the PDF for exact wording and diagrams.
Page 4 · Read text
CONTENTS
Page
Introduction 5
Inserting Battery 6
Mounting on Camera 7
Checking Flash Circuitry 8
Opening Reflector 9
Inserting Flashbulb- I 0
Charge Test Button ll
Flash Synchronization I2
Exposure Calculation l3
ExPosure Calculator Disc ---=--- I J
Guide Numbers_l 6
Bounce Flash-- I7
Flash Off Camera l8
Features/ Sp e cifications t9View original page 4Page 5 · Read text
INTRODUCTION www.butkus.us The light and compact BC-7 flash unit clips directly onto the Nikon F. It has a "three- way" socket to take any of three different types of flashbulbs, test circuits to test the bulb and the firing circuit, and an additional socket for triggering from the camera and synchronization of extension flash units. Since the unit is of the battery-capacitor type, it gives a constant light output, even when the battery is almost exhausted. The flashbulb itself acts as a switch in the flash circuitry, to prevent unnecessary drain on the battery' lts reflector is of folding design for compactness, and tilts through an arc of 120o, in 30o steps for bounce lighting. With the optional ac- cessory shoe, it can also be attached to Nikkormat cameras. The unit comes with a leather carrying case.View original page 5
Page 6 · Read text
INSERTING BATTERY
Power for the unit is supplied by a single small 15V
laminated dry battery, available anywhere, which is
housed in a battery chamber. Installation or replace-
ment is straightforward. Simply remove the rear
cover by pushing the cover clip downwards. When
inserting the battery, make sure that the positive
correctly and negative (+ and -) terminals are
aligned as shown inside the battery chamber. A vinyl
tape in the battery chamber makes battery removal
easy. Pass this tape under the battery when it is
being inserted.
www.butkus.usView original page 6Page 7 · Read text
www.butkus.usMOUNTING ON CAMERA
The unit fits directly on the Nikon F, and requires
no synchronizing cord. Slide it onto the accessory
shoe around the film rewind knob as far as it will go.
This connects the terminal in the flash unit with the
flash contact in the accessory shoe. Fitting or
removal is more easily done with the reflector
folded flat.
When used with Nikkormat cameras' an accessory
synchro cord is required. A special accessory shoe
which fits on top of the viewfinder is available for
using this unit with the Nikkormat. For details, see Nikon F
the Nikkormat instruction manual. Nikkormat
i
;'TYView original page 7Page 8 · Read text
CHECKING FLASH CIRCUITRY
The unit incorporates a test circuit with a buitt-in
test lamp to check the functioning of the synchro
contacts of the shutter, the flash terminal, the
capacrtor and the battery. Tilt the reflector upwards
so that the red circuit test button on the front of
the unit is easily accessible. Wind the film advance
lever ... (1), depress the circuit test button ... (2),
then after a few seconds press the shutter release
button on the camera ... (3). Instant lighting of the
test lamp indicates that the flash circuitry and the
battery are in good condition.
Caution: The above check should be carried out
prior to film loading.View original page 8Page 9 · Read text
OPENING REFLECTOR www.butkus.us The reflector is of a folding dcsign, and opens or closes like the segments of a Chinese fan. The segments are curved to give a parabolic reflector shape. The surface is grained to diffuse light evenly over the subject area, The angle of illumination is approximately 65", allowing complete coverage of the picture angle even when using 35mm wideangle lcnscs.View original page 9
Page 10 · Read text
INSERTTNG FLASHBULB
The unit has a "three-way" socket to take any of
the three different types of flashbulbs. Simply
insert the flashbulb into the socket and Dush it
firmly into place.
To remove, depress the ejector on top of the unit.
The hot, newly-fired bulb will pop out of the unit,
without the necessity of touching it by hand.
www.butkus.usView original page 10Page 11 · Read text
www.butkus.usCHARGE TEST BUTTON
In the battery-capacitor circuit, the flashbulb itself
completes the charging circuit, so that the capacitor
does not charge up until the flashbulb is inserted
into the socket. This arrangement preserves the
battery, since only the minimum amount of current
is used each time for the flash itself. After insertine
the bulb into the socket. press the white charge tesi
button on the side of the unit. Instant lighting of the
test lamp on the back of the unit shows that the
flashbulb in use is good and the capacitor has been
fully charged.
Note: As the battery becomes exhausted, the capaci-
tor takes longer to charge. This will result in a longer
time being required for the test lamp to light.
llView original page 11Page 12 · Read text
FLASH SYNCHRONIZATION
Almost all types of flashbulbs may be synchronized
with Nikon cametas. On the Nikon F, the flash syn-
chronization is accomplished by setting the synchro
selector and the shutter speed of the camera appro-
priately for the flashbulb. (The Photomic-series find-
ers must be removed in order to set the synchro-
selector ring). The table below shows the shutter
speeds appropriate to various kinds of flashbulbs. For
instructions on setting the Nikon F for flash, refer to
the Nikon F instruction manual. For electronic flash,
the selector should be set at FX. The Nikkormat
czmreras have two flash terminals marked "M" and
"X" on the side of the camera. When the M terminal
is used M and FP types of bulbs are synchronized at
all shutter speeds, while MF type bulbs are synchro-
nized at speeds slower than'1/60 sec. The X terminal
is used only for electronic flash. For instructions on
setting up the Nikkormat for flash, see the Nik-
kormat instruction manual.
1 000 500 250 125 60 30 lc I 2 i B.,r-...-q{Y**o
FP O a o a OF OF OF OF OF OF
O o OF OF OF OF OF OF
l\,4F
OF OF OF
t2View original page 12Page 15 · Read text
EXPOSURE CALCULATION continued
Example 1 Example 2
If the C.E. No. 6 (FP type) flashbulb is used, If the G.E. No. 68 bulb is used with the shut-
with the shutter set to.lll25 sec. and a black ter set at 1/125 sec. and with a color film of
and white film of ASA 160, the correct aper- ASA 64, the conect aperture indicated is
ture indicated is f/11, for a sublect 10 feet midway between f 14 and f 15.6 at the 10 feet
(3m) away. distance.
bo
''f ,I f'
14View original page 15Page 16 · Read text
www.butkus.us
Examole 3
When the AG-type flashbulb is used with the
shutter set to speeds slower than 1130 sec..
the film speed scale should be aligned with
the white dot adjacent to the 1/125 sec. set-
ting on the shutter speed scale, to determine
the correct aperture. For example, if the G.E.
AG-l bulb is used with the shutter set at l/30
sec. and with black and white film of ASA
160 rating at the 10 feet distance, rotate the
exposure calculator disc so that the white dot
appears opposite the 160 mark on the B&W
film speed scale. The correct finumber is
computed as f/ 1 1.
?.*: ys
t*, .
15View original page 16Page 17 · Read text
EXPOSU R E CALCU LATION continued
Guide Numbers
Besides the exposure calculator disc, exposure with
flash can also be determined by means of guide
numbers. The guide numbers are so computed as to
take account of the flash intensity and the film
speed, and are the product of the lens aperture and
the flash-to-subject distance. Every packet of flash-
bulbs provides guide numbers for all available types
and speeds of film. To find the correct aperture,
divide the guide number of the flashbulb in use by
the flash-to-subject distance. If the G.E. No. M2B
bulb, with a guide number of 200, is used 15 feet
away from the subject with the shutter speed set at
1/30 sec. and the film speed rating is ASA 125, the
correct aperture is calculated as 200+15 = f/13.3.
The published guide numbers are generally com-
puted on the basis of a flash unit with a fixed, large-
diameter reflector with a polished surface. Thus, use
of the published guide numbers will lead to slight
underexposure with the BC-7 flash unit, which has
a grained-finish collapsible reflector. About a half
stop of additional aperture should be added to com-
pensate for this. If the aperture calculated is f/13.3,
for example, adjust the aperture setting to about f/11.
16View original page 17Page 18 · Read text
www.butkus.usBOUNCE FLASH
The reflector can be tilted upwards through an arc
of 120o, in 30o steps for bounce flash lighting.
Direct the flash at light colored walls and ceilings.
The light bounced from the reflecting surface is
diffused, and the subject illumination is soft and
almost shadowless. However, a certain degree of
exposure increase must be added to that obtained
from the guide number, as the intensity of light is
reduced to a certain extent. The degree of the ex-
posure increase varies, depending on the reflection
characteristics, distance of the reflecting surface, etc.
t7View original page 18Page 19 · Read text
FLASH OFF CAMERA
To yield better modeling and shadow displacement,
the flash should be placed above orto,one side of the
camera. An accessory synchro cord lm long, is
available to connect the flash unit with the camera.
Plug one end of the synchro cord into the flash
terminal on the ciunera and fit the other end in the
synchronization cord socket on the side of the flash
unit.
18View original page 19Page 20 · Read text
FEATU R ES/SPECI F ICATIONS www.butkus.us
Three-way tyPe flashbulb socket ^ Angle of illumination aPProx. 65"
Cotlapsible type reflector tilts upwards through
l20o in 30o steps for bounce lighting
Battery-capacitor Power source
Test lampi give instant check of bulb and flash
circuitry
a Synchro cord socket Provided
a Direct, cordless connection to the Nikon F
a 15V laminated batterY
o Weight approx. 180g without batteryView original page 20From the M. Butkus archive. Original publisher and archive notices are retained.
Check the model and edition against your equipment.
PDF verified 2026-10-10.