Nikon SPEEDLIGHT SB-16 - Manual (Page 42)

CONTROLS IN DETAIL —continued
Now, you are ready to read the usable f/stop from the
dial. Each color-coded line indicating the auto shooting
range for each f/stop has a notch on it. Find the notch
directly above the flash-to-subject distance and read
the f-number at the end of the line.
Example
With ASA/ISO 100, zoom head set at N for 35 mm lens,
a subject 2m (6.6 ft.) away, the aperture is approx, f/4.
With a subject 4m (13 ft.) away, the aperture is f/2.
Without referring to the exposure calculator dial, you can
also determine the f/stop by using the guide number
equation found on page 30.
The guide number at various film speeds and zoom head
settings is shown in the following table:
Guide numbers in the MD mode
Unit: m (ft)
Zoom head
setting
ASA/ISO film speed
800 400 200 100 50 25
T 30 (98) 21 (69) 14 (46) 10 (33) 7 (23) 5 (16)
s 27 (89) 19 (62) 13 (43) 9.5 (31) 6.7 (22) 4.7(15)
N 22 (72) 16 (52) 11 (36) 8 (26) 5.6(18) 4 (13)
Wi 19(62) 13 (43) 9.5 (31) 6.7 (22) 4.8(16) 3.3(11)
12(39) 8.4 (28) 5.9(19) 4.2(14) 3 (9.8) 2.1 (6.9)
* IV 2 is used when the wide-flash adapter is attached to the flash unit
with the zoom head set at W t.
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