Nikon os Speedlight SB-102 - Manual (Page 26)

Example 3:
Shooting a subject on land at 8m (26.2ft) without using
the wide-flash adapter while using ASA/ISO 100 film
and “MFULL”: The GN for "MFULL” at ASA/ISO 100
on land is 32 (from the chart below). Divide the GN of
32 by the flash-to-subject distance of 8m to get the
correct aperture, f/4. Because water absorbs a great
deal of light, however, you cannot use the same GN
underwater as on land or your shot will be underexposed.
Instead, multiply the on-land GN by 1/2 to 1/3 for under­
water photography. (The underwater GNs shown in the
following chart are 1/2 of the corresponding on-land
GNs.)
Guide Numbers in the Manual Mode
CONTROLS IN DETAIL —continued.
Film
speed
On-land shooting Underwater shooting
(ASA/
ISO)
“MFULL” “M1/4” “M1/16” “MFULL” “M1/4” “M1/16”
1600 128(90) 64 (45) 32 (22) 64 (45) 32 (22) 16(11)
800 90 (64) 45 (32) 22(16) 45 (32) 22(16) 11 (8)
400 64 (45) 32 (22) 16(11) 32 (22) 16(11) 8(5.6)
200 45 (32) 22(16) 11 (8) 22 (16) 11 (8) 5.6 (4)
100 32 (22) 16(11) 8 (5.6) 16(11) 8(5.6) 4 (2.8)
50 22(16) 11 (8) 5.6 (4) 11 (8) 5.6 (4) 2.8 (2)
25 16(11) 8(5.6) 4 (2.8) 8 (5.6) 4 (2.8) 2(1.4)
• The values in parentheses are when the W ide-Flash Adaptor
SW -102 is being used.
• The full amount of light is emitted when the shooting mode selector
is at "MFULL" and, even if not synchronized, at "AUTO."
Exposure Compensation
When the Nikonos-V is used with the SB-102 in the TTL
or non-TTL flash mode, exposure compensation is re­
quired for over- or underexposing the picture to match
subject or shooting conditions. Each procedure is dif­
ferent, so read the following instructions carefully be­
fore shooting.
In addition, if you photograph a subject with very high
reflectivity, such as a mirror or metallic surface, under­
exposure is almost certain to occur. To prevent this, use
manual flash control.
TTL Exposure Compensation
When using TTL automatic flash control with the
Nikonos-V camera, you can use its ASA/ISO film speed
dial to make an exposure compensation for the shooting
situation or to create intentionally over- or underexposed
photos.
The relationship between the exposure compensation
value and ASA/ISO film speed dial setting is shown in
the following chart:
Exposure Compensation Value
(New ASA/ISO Setting)
ASA/ISO Film
Speed in use
4-2 4-1 0 -1 -2
25 — — 25 50 100
50 — 25 50 100 200
100 25 50 100 200 400
200 50 100 200 400 —
400 100 200 400 — —
The useable aperture range for TTL automatic flash
photography changes according to the exposure com­
pensation value being used. Before using the exposure
calculation dial to determine the useable aperture
range, align the correct shooting situation mark with
new (compensation) setting on the ASA/ISO film speed
scale.
For example, to make a -F2 exposure compensation
when using ASA/ISO 100 film, reset the ASA/ISO film
speed scale to ASA/ISO 25, then read the modified
shooting distance from the dial.
•Positive (-F) exposure compensation cannot be made at some film
speeds, and negative (-) exposure compensation cannot be made at
other film speeds. In these cases, make the necessary compensation
in the non-TTL automatic mode (see page 24) or use one of the manual
flash modes.
• W hen you finish making the exposure compensation, be sure to reset
the ASA/ISO film speed dial on the Nikonos-V and the ASA/ISO film
speed scale on the speedlight.
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