Canon Speedlite 550EX Instructions Manual page 97

Y" 56
! •
StroboscopIc Flash
2
Use the fol lowing formula to calculate
the required shutter speed.
Flash count
~
Firing frequency
==
Shutter speed
Example:
If the flas h count is 10 and
the fir ing frequency is 5 Hz , the
shutter speed will have to be at
least 2 sec.
1 0~5=2
-,
-.
II the Ilash count display
is - - ,
the Ilash will
keep firing unti l the shutter speed ends or
un til the max imum numbe r of continuous
flashes (as ind icated in the table on page
122) is fired.
3
Focus the subject.
" To set the exposure sett ings, see "Manua l
Flash Mode" on page 93.
4
Check that the
~
icon is displayed in
the viewfinder, then take the picture.
To prevent overheati ng 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 to minutes.
->'- .
Stroboscopic flash is most effective with highly reflectjve subjects in front of a dark
background .
.
..,-
Using a tripod and Remote Switch are recommended.
Using an external power sou rce is recommended lor stroboscopic flash.
Stroboscopic flash cannot be used at a flash output of 111 or tl2.
bulb
can also be used with stroboscopic flash.
9