Canon 577 G - Manual (Page 29)

BOUNCE FLASH
ON MANUAL
When the flash is bounced off a wall
or ceiling before it reaches the sub­
ject, it is actually traveling a longer
distance than it would be if it were
aimed directiy at the subject. As a
result, the light intensity is weaker
and it is necessary to take this extra
distance into account to be sure of
correct exposure. As long as the
auto check lamp (p. 16) lights up
after actuai or test firing, there will be
enough light. It is important to re­
member that the distance scaies on
the back of the unit do not apply
when the flash is bounced. Other
than that, the flash may be used as
usual.
The surface off which the flash is
bounced shouid preferably be white
or near-white, fairly large and highly
reflective, if the reflecting surface is
colored, the subject may turn out
tinted that coior. The color may also
be disappointing if the surface is a
poor reflector. A very high ceiling
does not make a good surface for
bounce flash; a better solution wouid
be to bounce the flash off a white-
card reflector. Generally, the closer
the flash is to the surface, the
brighter and higher in contrast the
picture.
it is generaily said that there is a
loss of light intensity of about two
f/stops when the flash is bounced off
a 2.5 meter high ceiiing. Losses of
this order require an adjustment in
the
f/stop calcuiated by guide
number formuia when the flash
mode switch is on MANU. Since the
exact correction depends on the dis­
tance of the reflecting surface from
the flash and subject, its color and its
reflectivity, it is best to bracket ex­
posure.
26