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Underwater Strobes:
Part 2. Power Ratings
Strobes are normally categorized
by various methods, but the most important factor is power rating.
Typically strobes are rated in foot candles, watt-seconds or
guide numbers
(covered in the Tips and Tricks section.) The higher the
number, the more powerful the strobe.
Knowing the true guide number of
a strobe is especially useful (foot candles and watt-seconds being
comprehensible to only physicists) since it allows the
photographer to determine the proper exposure manually.
A true guide number of 32 or
more (with 100 ISO setting) is considered powerful, whereas one
rated at 16 is considered somewhat weak. Note that this is in no
way a criticism of small strobes.
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Compact Strobe |
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Powerful Strobe |
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