closer to the camera, parallax—the difference in the
views seen by the photographer and the lens—can
easily lead to the improper framing of the picture.
The use of a viewfinder or a framer can help pre-
vent these errors by literally framing the view as
seen by the lens. Another way to avoid the effects
of parallax with a range-finder camera is to use a
wide-angle lens. This is most effective when photo-
graphing large subjects, and allows the inclusion of
a wider field of vision. In the past decade, Nikon
introduced the first auto-focusing SLR underwater
camera, the Nikonos RS, illuminating the need for
an accessory viewfinder. Cost factors and personal
preference lead many to still opt for the range
finder camera, Nikonos V.
Each photographer, professional or recreational,
has an individual predilection for underwater cam-
era systems. Amphibious Nikonos-type cameras are
often the choice of the fledgling aquatic photogra-
pher, due to their ease of use and lower cost. Along-
side competing cameras, such as the Sea & See
Motormarine, the Nikonos continues today to be a
favorite camera for many underwater photogra-
phers, as well as adventurers or others in need of a
rugged, weather-proof camera. Amphibious cameras
are utilized by amateurs and professionals alike,
sometimes in combination with a housed camera
system. Frequently, experienced underwater photo-
graphers take two cameras on a dive, each prepared
for different sized subjects; after all, one never knows
when a whale shark will glide by, or a tiny cleaner
shrimp will pose for the perfect portrait. And with
the use of a digital camera in an underwater housing,
the photographer can now view the images captured
without the delay of processing time. Mistakes can
be caught and corrected during the next dive.
Despite the importance of reliable and suitable
equipment, a good camera system alone does not
guarantee quality pictures. The successful under-
water photographer recognizes that the rules of
topside photography do not necessarily hold during
submersion. Of utmost importance for the under-
water photographer is the behavior of light in the
medium of water, as well as certain properties of
water itself. Light rays travel differently through
water than through air, and a certain percentage
of the natural light present at any given time will
reflect off the surface of the water. The amount of
light that penetrates the surface is dependent upon
the angle at which light hits the water, and the sur-
face conditions of the water; in general, a maximum
amount of light will derive from light striking a
calm surface at a 90 degree angle. Yet, even in an
ideal situation with minimum reflection, two other
phenomena must be taken into account: refraction
and scattering. Light rays that do enter the water
refract, or bend, as they travel from the air into the
denser medium of water. Because water is 800 times
denser, the light rays do not travel as far as they
would in air. Thus, the strength of the light quickly
decreases as depth increases. In addition, as a result
of refraction, objects underwater appear 33 percent
larger and 25 percent closer than on land. In terms
of photography, this leads to a reduced angle of
coverage by a given lens (a topside 35 mm lens
behaves as a 28 mm lens underwater). Light quality
is further compromised by minute suspended parti-
cles in the water. Even the clearest of water contains
participate matter that scatters the penetrating
light, weakening its intensity. Greater concentra-
tions of suspended particles decrease the clarity of
the water and increase the instances of scattering. In
the presence of a flash bulb or strobe light, sus-
pended particles can capture and reflect the artifi-
cial light; this phenomenon, called backscattering,
leads to an image obscured by white or bright
specks, as though the picture were taken in the
midst of a snowstorm.
Color is also greatly affected by the medium of
water, which in effect acts as a blue filter. The
component rays of the white light spectrum are
absorbed by the water at varying depths: red loses
its intensity at a depth of 15 feet; orange vanishes at
30 feet; yellow fades around 60 feet; and green dis-
appears by 80 feet. Everything below 90 feet
appears blue, and, depending on surface light con-
ditions and water clarity, begins fading to black
soon thereafter. To counter loss of color, photogra-
phers must work in very shallow depths on bright
sunny days, or use an artificial light source. In the
days of the Calypsophot, magnesium based flash
bulbs were most commonly used to provide artifi-
cial lighting. Yet, flash bulbs were quite unreliable
and even dangerous; they often misfired and some-
times exploded. In addition, a bulb was good for
only one flash and had to be changed before each
picture was taken. These factors combined to make
the battery-run electronic flashgun, or strobe light,
a welcome improvement and the artificial light
source of choice. A strobe light, connected via a
cord to the camera or the housing, can be synchro-
nized with the camera shutter. As the picture is
taken, the strobe emits a bright flash and illumi-
nates the subject. In addition to artificial light,
colored filters may be layered over the lens or
employed during the developing process to counter-
act the color distortion. Thus, with the proper use of
lighting equipment and corrective filters, color can
be restored to objects photographed at any recrea-
tional diving depth.UNDERWATER PHOTOGRAPHY