Nikon os Speedlight SB-102 - Manual (Page 22)

CONTROLS IN DETAIL —continued.
Exposure Calculation Dial
In flash photography, which apertures can be used is
closely related to the flash-to-subject distance. To deter­
mine the useable apertures, align the shooting situation
mark on the exposure calculation dial with the ASA/ISO
film speed in use, find the flash-to-subject distance on
the distance scale, then follow the corresponding dis­
tance line up to the aperture scale.
The dots on the ASA/ISO film speed scale indicate the
following intermediate settings:
ASA/ISO film speed scale
25 50 100 200 400 800 1600
32 40 64 80 125 j
160
250 I
320
500 I
640
1000 j
1250
• The exposure calculation dial can be removed to clean sand or other
foreign matter from behind it.
Removing the Exposure Calculation Dial:
Remove the exposure calculation dial screw @ by turn­
ing it counterclockwise with a coin, then pull up on the
dial.
To re-attach the dial, correctly align its center notches
with the mounting notches on the back of the flash
head and push down on the dial. Insert the exposure
calculation dial screw and turn it clockwise as far as it
will go.
TTL Automatic Flash Control
In TTL automatic flash photography, the useable aper­
tures are from f/2.8 to f/22 (when using ASA/ISO 100
film), although the actual range tor a specific shooting
situation depends upon the flash-to-subject distance.
The actual ranges for specific situations can be easily
determined with the exposure calculation dial.
Example 1:
When the shooting situation mark is opposite the
100 on the ASA/ISO film speed scale and you want to
shoot at f/5.6, you can take pictures of subjects located
between 1 m (3.3ft) and 5.6m (I8.4ft).
When the shooting situation mark « m is opposite the
400 on the ASA/ISO film speed scale and you want to
use f/5.6, you can shoot subjects located between 0.7m
(2 3ft)and 4m (13.1 ft).
Before you select an aperture to use, always take the
flash-to-subject distance into consideration. To increase
the flash-to-subject coupling distance as much as pos­
sible, select a larger f/stop (a numerically smaller
f-number). In the opposite case, close-up shooting,
select a smaller f/stop (a numerically larger f-number).
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