this on every ocean dive as we descend away from the
sun. The practical application for photography is that
strobe light doesn’t reach very far. Depending on the
strobe power and clarity of the water, the strobe flash
may not reach subjects more than a few feet from the
camera. In wide-angle reef photographs you can often see
the transition where the colorful reef in the foreground
turns to blue-gray coral in the background.
In reef photography, the way artificial light falls off with
distance can be a useful tool for bringing the viewer’s
attention to the foreground subject. In caves, it works
against the photographer. Without the less-detailed,
ambient-lit backgrounds to provide context and scale for
the object of interest, disembodied objects float in the
black. Any subject farther away than the strobes’ limited
reach is lost in the darkness. The foreground subject could
be anywhere, and conveying the beauty and grandeur of
the space in which it floats is tricky.
More Light
The solution? More light! Getting additional lights in the right
places is crucial, and in some caves strobe positioning makes
more of a difference than total power output. Photographers
who venture into caves with two big strobes attached to
their cameras may be disappointed to see their photos lack
depth. When using only on-camera strobes, all the light in
the photograph comes from a single point (or two points very
close together) beside the camera. This straight-on lighting
arrangement flattens details and textures, removes shadows
and diminishes the third dimension.
To overcome this, move strobes away from the camera.
Off-camera lighting is where caves allow real creativity —
the uniformly pitch-black cave environment means the
photographer gets to choose which parts of the picture
to illuminate and which to ignore. Light from multiple,
separate sources brings back the third dimension and lets
the viewer see both foreground and background.
Off-camera lighting opens up a multitude of creative
choices. Additional strobes can be placed to backlight
key features, outline the entrance to a tempting side
tunnel or light your buddies’ expressions as they check
out the scenery. If your dive team carries strobes
positioned like dive lights in their hands, the images will
look more natural and familiar to those who have been
cave diving. Or you can go for a Hollywood look, hiding
strobes behind rocks to make glowing walls. The options
are limited only by your gas supplies, battery life and
buddies’ patience.
Strobe Solutions
There are technological challenges in getting multiple
strobes to fire in sync. The difficulties of shooting in
complete darkness are obvious, but this is one area where
darkness is a great bonus. Many underwater strobes have
built-in sensors so they can be triggered by the flashes of
other strobes or directly from the camera via fiber-optic
cable. A flash from the strobe that’s connected to the
camera can trigger the off-camera strobes. The speed of
light means the cascade of flashes moves faster than the
camera’s shutter, and all the strobes fire together. This can
be tricky in daylight zones where sensors may be confused
by sunlight flickering through the water. In darkness,
however, sensors are much more sensitive to distant flashes
of light and can be reliably triggered from farther away.
Built-in sensors are generally fixed to the bodies of strobes,
and they may not always be ideally placed. Some strobes’
sensors, for example, are embedded in the reflector, so if the
strobe is facing a distant wall the sensor won’t be facing the
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Opposite: On-camera strobes gently light the formations in McCavity Cave
and trigger the strobes held by the divers behind.
Below: Hand-held strobes light the background of each cave and create a glow in the
hazy water in Engelbrecht’s Cave and Ag’s Dreamtime Tunnel, Olwolgin Cave.