13.4 Flash exposure memory FE
Several cameras feature a flash exposure
memory (FE; Flash-Exposure). The flash unit
supports this during ETTL flash mode.
It can be used to define and store the expo-
sure level for the subsequent shot before the
shot is actually taken. This can be useful
when, for example, the flash exposure has to
be adjusted to specific details that may not
be necessarily be identical with the main
subject.
This function is activated on the camera. The
subject details for the flash exposure are
measured and brought into focus by the
cameraís AF sensor/metering window.
Pressing the cameraís FE button (the descrip-
tion varies from camera to camera; see came-
ra operating manual) causes the flash unit to
fire an FE test flash.
k
The stored metering value, for example „EL",
is then displayed in the camera viewfinder.
The camera uses the reflected light of the
test flash to determine the light output requi-
red for the subsequent exposure. The actual
main subject can then be brought into focus
with the camera's AF sensor/metering wind-
ow. When the shutter release is pressed, the
picture will be exposed with the previously
defined light output of the flash unit!
The flash exposure memory FE is not suppor-
ted during the green fullyautomatic program-
me, the Vari programme and the subject pro-
grammes! Further details regarding settings
and handling can be found in the camera
operating manual!
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14 Flash synchronisation
14.1 Automatic flash sync speed control
Depending on the camera model and camera
mode, the shutter speed is switched to flash
sync speed when flash readiness is reached
(see the camera's operating instructions).
Shutter speeds cannot be set faster than the
flash sync speed, or they are switched auto-
matically to the flash sync speed. Various
cameras have a sync speed range, for exam-
ple from 1/60 sec to 1/250 sec (see the
camera's operating instructions). The sync
speed set by the camera depends on the
camera mode, the ambient light, and the
focal length of the lens used.
Shutter speeds slower than the flash sync
speed can be set according to the camera
mode and the selected flash synchronisati-
on.
If a camera with a between-the-lens shutter
and high-speed synchronisation (see 7.4) is
used, flash sync speed is not controlled auto-
matically. As a result, the flash can be used
at all shutter speeds. If you need the full light
output of the flash unit, you should not
select a shutter speed that is any faster than
1/125 sec.