Canon 550ex - Page 48

E
Stroboscopic
Flash
)
Use the
following
formula
to
calculate
h
the
requireci
shutter
speed.
Flash
count
+
Firing
frequency
=
Shutter
speed
Example:
lf
the
flash
count
is
10
and
the firing
frequency
is
5
Hz,
the
shutter
speed
will
have
to
be at
least
2
sec.
10+5-2
.
lf
the
flash
count
display is
- -
,
the flash
will
keep
firing
until
the
shutter
speed
ends
or
until
the maximum
number
of continuous
flashes (as
indicated
in
the table
on
page
122)
is fired.
e
Focus
the
subject.
t
.
To
set the
exposure
settings,
see
"Manual
Flash
Mode"
on
page
93.
A
Check
that
the
t
icon
is
displayed
in
-?
the
viewfinder,
then
take
the'piciure.
To
prevent
overheating
and deterioration
of the
flash
head,
do not
use
stroboscopic
flash
for
more
than
10
frames
in rapid
succession.
After
10 frames,
allow
the 550EX
to
cool for
at
least
10
minutes.
'
Stroboscopic
flash
is
most
effective
with highly
reflective
subjects in front
of
a dark
background.
**
.
Using
a tripod
and Remote
Switc["ere
recommended.
'
Using
an external
power
source is'recommended
for
stroboscopic
flash.
'
Stroboscopic
flash
cannot
be used
at
a
flash
output
of
111
or
112.
.
bulb
can also
be
used
with
stroboscopic
flash.
97