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Even
if your camera has a built-in flash, you may
still find that a separate portable flash unit
will solve lighting problems that the built-in
flash can't handle. If you want to use bounce
flash, for example, or need more light than
your in-camera unit can provide, the only answer
is a separate flash unit.
If your camera does not have built-in flash,
a portable unit is a necessity. Mounting an
automatic flash on your camera can transform
it into a handy point-and-shoot model with automatic
exposure courtesy of the automation built into
virtually all flash units today.
When
you start shopping for a suitable flash unit,
your first step should be to become familiar
with the various types of portable flash on
the market today.
The basic flash is a relatively compact model
that slips into the accessory shoe of your single-lens
reflex and is synchronized automatically through
the flash contact in your camera. With these
units, you set the correct shutter speed for
proper synchronization—usually 1/60 or
1/125 second. Then you set your lens aperture
according to the instructions on the flash calculator
dial. This aperture will provide satisfactory
exposures automatically over a specified distance.
Most flash units permit the use of several apertures—for
example, f/2.8, f/5.6, and f/11. The flash range
varies with the selected aperture. For example,
at f/5.6, the flash would give you correct exposures
from three feet to 30 feet. At f/ll, the automatic
flash range might be from two to 20 feet. In
general, the minimum flash distance for automatic
exposure is usually about ten percent of the
maximum distance.
A typical shoe-mount unit should cost approximately
$60 to $80. Features to look for include ability
to use bounce flash, variable reflectors for
use with lenses from wide angle to telephoto,
and a range of accessories such as brackets
and remote sensors to permit off-camera use
if desired.
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