When I think of the thought process
people go through in selecting a strobe for underwater photography,
it hearkens me back to when I was a teenager "souping
up" my first car engine. When it came to power, there
was simply no room for compromise. You went all out for every
smidgen of power you could possibly afford. If more carburation
meant more power, then the rule was "if some is good
- then more must be better; if more is better, then too much
must be just right." And so it is for most of us when
it comes to selecting a strobe. Our first inclination is to
acquire the biggest cotton-picking flamethrower that our significant
others will allow us to buy.
You would probably be better off doing a little forward thinking
as to what you ultimately want as a total system before buying
your first strobe. Basically, there are just two classes of
strobes - big strobes and little strobes. There will generally
be little more than two f-stops between any member of one
class and any member of the other - usually only one stop.
Yet their size may differ by a factor of ten, and their power
may vary by a factor of several times when measured in watt
seconds. The larger strobes use most of their power to cover
a larger area with light (usually around 100 degrees) then
do the small strobes, which generally cover only about sixty-five
to around eighty degrees. It is therefore useful to think
of the two classes of strobes that can be used for fish portraits.
I unhesitatingly recommend that you buy a macro strobe for
macro and a wide-angle strobe for wide-angle. You could us
a wide-angle strobe for macro, but it will be clumsy as hell.
It will be a major struggle getting it into the tight places
where many macro subjects are often found, and it can all
but totally obscure any view of whatever it is that you're
trying to photograph. It's kind of possible with a housed
camera but is a universally recognized form of self abuse
when mounted to a Nikonos. You will almost certainly be unable
to successfully use a macro strobe for wide-angle since they
simply don't have the juice. Of course, some type of shots
can be possible when tropical ambient light isn't a factor,
but you will generally be attempting wizardry against the
Then how about a "midsize" strobe for macro and
wide-angle? Sounds reasonable! The fact is that just about
any macro strobe on the market will do the macro deed well.
If you have a situation that requires a lot of light, such
as a 1:1 shot at f-22 or even f-32 (effective f-stops of forty-five
and sixty-four, respectively) on a slow film like Velvia,
you can simply move the strobe in closer to the subject. You
will increase illumination more effectively and easily this
way than by increasing the power of the strobe. Going to a
midsize strobe doesn't give you much more light for macro
since you probably won't be able to get it in as close. You
might reasonably select a midsize strobe for a feature not
found on small strobes - a modeling light, for instance. If
macro is your game, just pick on with the features you want
at the price you like - no problem. Of course, none of this
takes the "quality" or "shape" of the
light into account, but that's another major question (argument)
How about using a midsize strobe for wide-angle Using these
less powerful strobes to cover a larger area generally leaves
you underlit. Using two helps; and for some types of lighting,
and lighting in low ambient conditions, this can be adequate.
Wide-angle strobe choice, in fact, may lend some credibility
to that old adage, "If some is good, more is better .
. ." Moving your strobes closer to the subject when more
light is needed for a wide-angle shot is usually a poor option.
It takes real long arms, and the strobes generally don't look
good in the shot. The general rule of thumb is that light
falls off roughly an f-stop per foot. A strobe with twice
the power will allow you to back up a foot for more coverage
or close down a stop for more depth of field.
As to your confusion about comparing manufacturers' model
numbers in deciding which strobe will do the job for you,
I am at a loss. What's confusing about this? A Nikon SB 104
is more powerful than an SB102, SB103, or SB105. The SB102
is more powerful than the SB103 or SB105. An SB104 is about
a stop bright than an Ikelite 150 or a Sea & Sea 200 or
300. The guide number of an Ikelite 300 is within a hair of
an SB104 and about a stop brighter than a Sea & Sea 300.
The New Ikelite 200 is brighter than the Sea & Sea 200
or 300. Like, what's the problem? You could use the manufacturers'
guide numbers, except they lie about guide numbers. Bottom
line is that features other than power, such as recycle time,
size and weight, factory service, charging characteristics,
modeling lights, and of course, the ever popular price consideration,
will play a very important part in intelligent strobe selection.
Most big strobes will do the big job. I hope everything is
clear for you now.