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that may not necessarily be identical with the main subject.
Set the flash unit to E-TTL flash mode (see 4.1.1). Focus the camera’s AF sen-
sor metering area on the zone whose flash exposure is to be predetermined.
When the FE button on the camera is actuated the flash unit will fire an FE
test flash (the designation FE may vary with individual camera models -
please refer to the operating instructions for the given camera). The electronic
measuring circuit inside the camera assesses the light reflected from the FE
test flash to determine the light output required for the subsequent exposure.
The main subject can thereafter be focused with the AF sensor metering area
of the camera. When the shutter release is pressed the picture will be ex-
posed with the previously determined light output.
Due to system-inherent reasons any changes in the light situation after
the FE test flash has been fired will not be taken into account when the
picture is shot.
Some cameras do not support FE flash exposure storage in the “green”
full auto mode and programmed image control modes (see camera’s
operating instructions).
5. Flash unit and camera functions
5.1 Flash readiness indication
The flash readiness symbol lights up on the flash unit when the flash capa-
citor is charged, thereby indicating that flashes can be fired for the next shot.
Flash readiness is also transmitted to the camera for corresponding display in
the viewfinder (see 5.3).
If a picture is shot before flash readiness is signalled in the camera’s view-
finder, then the flash unit will not be triggered so that the exposure may be
incorrect if the camera has changed over to flash sync speed in the meantime
(see 5.2).
5.2 Automatic flash sync speed control
Depending upon the camera model and camera mode, the shutter speed is
changed to camera sync speed when flash readiness is reached (see camera’s
operating instructions). Shutter speeds faster than the camera sync speed cannot
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be adjusted or they are automatically changed to the camera’s sync speed.
Various cameras have a sync speed range, e.g. 1/30th sec. to 1/125th sec.
(see the camera’s operating instructions). The actual sync speed set by the ca-
mera depends upon 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, depending upon
the given camera model and the selected flash synchronisation (see also
4.6.2 and 4.6.3).
Some digital cameras, e.g. PowerShot Pro 90 IS, G1 and G2, do not
provide automatic flash sync speed control. These cameras permit the
use of all shutter speeds. If the full light output of the flash unit is re-
quired, then do not set a shutter speed faster than 1/125 sec.
When in FP high speed synchronisation mode (HSS mode) some ca-
meras allow shutter speeds faster than the camera’s flash sync speed
(see 4.6.4).
5.3 Displays in the camera’s viewfinder
Flashing flash symbol:
Use or switch on the flash unit (on some cameras)!
Illuminated flash symbol:
The flash unit is ready for use (on some cameras).
Some cameras feature a faulty-exposure warning function in the viewfinder:
Accordingly, the stop value, the shutter speed or both displays, will flash in
the viewfinder to indicate over- or underexposure.
Fundamentals in connection with faulty exposures:
• With overexposure: Do not flash!
• With underexposure: Switch on the flash unit or use a tripod and set a
slower shutter speed.
There can be various reasons for faulty exposures in the different exposure
and automatic programs.
Refer to the operating instructions to establish whatever is applicable
to the displays in the viewfinder for the given camera model.
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