Metz 36 AF-4 O - Manual (Page 82)

instructions) the flash unit will fire an FE test flash. The elec-
tronic measuring circuit inside the camera assesses the
reflected light of 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 exposed 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 or programmed image control
modes (see camera’s operating instructions).
5.7.3 Nikon i-TTL flash mode
i-TTL flash mode is an advanced variant of the standard TTL
flash control of analog cameras. When shooting a picture,
several weakly visible preflashes are fired by the flash unit
prior to exposure. The camera then evaluates the reflected
preflash light so that the subsequent flash exposure is opti-
mally adapted to the prevailing photographic situation.
When the TTL flash mode is selected, the flash unit automa-
tically activates standard TTL or i-TTL flash mode, depending
on the type of camera.
Flash exposure memory
Some cameras have flash exposure memory (FV memory).
This is supported by the flash unit in i-TTL flash mode. It can
be used to define and store the exposure level for the subse-
quent shot before the shot is actually taken. This can be use-
ful when, for example, the flash exposure has to be adju-
sted to specific details that may not necessarily be identical
with the main subject.
This function is activated on the camera, in some instances
as an individual function.
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