Instruction manual
and the
effect
of
red-eye
is
minimized
in the final
photo.
(This feature
is
called red-eye reduction,
not
red-eye
elimination—the
only
way to
eliminate
red-eye
is to
move
the flash
unit off-camera.
More
on
that
in a
bit.)
Slow
Sync:
Most automatic cameras will
not let you
make long available-light exposures using
flash.
They
normally
set a flash
sync speed that enables
you to
hand-
hold
the
camera.
This
results
in a
dark background,
but
with
the
nearby subject correctly exposed
by the flash. If
you use
slow sync,
you can set the
camera
at a
very slow
shutter
speed
and the
camera will automatically balance
the
low
light exposure with
the flash. You may
have
to use a
tripod
to
avoid camera movement
and
have
the
subjects
limit
their movement
for the
exposure.
On the
other hand,
you may be
creative
and
have
the
subjects move throughout
the
exposure, resulting
in
burred movement.
Rear-Curtain
Sync:
Normally,
the flash fires at the
beginning
of the
exposure.
This
flash
exposure lights
the
subject,
resulting
in a
sharp image,
and
then
a
blurred image
is
recorded
from
the
ambient light.
The
blur shows
up
after
the
sharp image
was
recorded,
but is
positioned
in
front
of
the
subject
in the
photo.
With rear-curtain sync,
the flash
fires at the end of the
exposure, resulting
in
blurred
movement behind
a
moving object.
This
effect
is
mainly
used
to
give
a
feeling
of
motion
to the
image.
Slave
Flash:
You can
also
use
several
flash
units
to
light
a
scene,
by
attaching
a
small
electronic device called
a
slave
to
the
auxiliary
flashes. The
slaves
will
trigger
the
units
to
which they
are
attached when
the flash
on-camera
fires.
Some
flash
units have this slave function built-in,
so all you
have
to do is
turn
a
switch.
The
output
from
the
slave unit
varies,
depending
on the
sophistication
of the flash.
Some
units
can
only dump
full
power, while others feature variable
power settings. Often
the
slave unit mimics
the
main
flash
and
shuts
off its
output when
the
main
flash
does.
Most
dedicated
slave units feature
full
TTL
capability
via
optical
or
radio cordless transmission.
AF-Assist
Light:
The
AF-assist light
is a
special light
grid that
is
projected
out to the
subject when there
is not
enough light
for the
camera
to
accurately focus.
The
camera
is
then able
to
focus quickly
on the
grid
as it
falls
on the
subject.
This
grid light
is
usually
in the red
part
of the
spectrum
and is
hardly visible
to
anyone.
Dual
Flash
Head:
This
type
of flash has a
smaller
flash
head under
the
main
flash
head.
The
smaller
flash
works
as
a
fill
light,
and the
larger head above
can be
rotated
to
bounce
the flash to
soften harsh shadows.
You
have
the
option
of
turning either
flash
head
on or off for
lighting
versatility.
Ring
Flash:
Medical, scientific,
and
nature
photographers sometimes need soft lighting
to
highlight
macro subjects from
all
sides.
The
ring
flash is a
circular
flash
assembly made
up of
curved
flash
tubes.
You can fire
all
of
them equally,
at a
ratio,
or
turn
any of
them off,
depending
on the
lighting pattern
you are
trying
to
achieve.
The flash
tube assembly mounts
on the
front
of the
macro
lens itself. Many
of
these specialized units feature
an
additional
focus light
and
power pack
to
offset
the
added
power consumption.
Flash
Accessories:
Flash manufacturers
and
third-party
58
2002
PnoTOgraphic
Buyer's
Guide