Nikon SB-102 instruction manual Exposure Calculation Dial, TTL Automatic Flash Control

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 ASAIISO 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 ASAIISO fi lm speed scale indicate the following intermediate settings:

ASA/ ISO film speed scale

25	• •	50	•	100	200		• •	.) 00	• •	800		1600
•		• •		• •	•	•		•		•	• •	•
	32 40	64	80	125	+	250 +		500 j			1000 j
					160		320		640		1250

•The exposure calculation dial can be removed to clean sand or other foreign matter from behind it.

TTL Automatic Flash Control

In TTL automatic flash photography, the useable aper- tures are from f/2 .8 to f/22 (when using ASAIISO 100 film), although the actual range for 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.

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.

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 1m (3.3 tt) and 5.6 m (18.4 ft).

When the shooting situation mark ~ is opposite the 400 on the ASAIISO film speed scale and you want to use f/5.6 , you can shoot subjects located between O.7m (2 3tt) and 4m (13.1 tt) .

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 flstop (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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