Canon EOS-1D Mark IV - Manual (Page 216)

Custom Function Settings
C.Fn II -6 Shutter curtain sync.
0: tst-curtaln synchronization
1; 2nd-curtain synchronization
The flash fires immediately before the exposure ends. When this is
combined with a slow sync speed, you can create a trail of light such as
from car headlights at night.
This Custom Function can be used to obtain 2nd-curtain sync effects even with
EX-series Speedlites which do not have this feature (except Speedlite 270EX).
o • When using EX-series Speedlites having the shutter curtain synchronization
function, C.Fn II -6's setting does not take effect. Set the shutter curtain
synchronization in the Flash functions settings menu (p.122) or directly on the flash,
m When using a Speedlite 270EX, shutter curtain synchronization can be
set in the Flash functions settings menu.
• If 1 is set and you press the shutter button completely, note that the flash
will fire a total of two times right before the exposure ends.
• When using 2nd-curtain sync, set the shutter speed to 1/50 sec. or
slower. If the shutter speed is 1 /60 sec. or faster, 1 st-curfain sync will be
applied even if 1 is set.
C.Fn II -7 Flash firing
Enables or disables the firing of an external flash or non-Canon flash
connected to the PC terminal.
0: Enable
1: Disable
Convenient when you want to use the external flash’s AF-assist beam
only. Note that whether or not the AF-assist beam is emitted depends on
the C.Fn III -15 setting.
C.Fn II -8 Viewfinder info, during exposure
0: Disable
1: Enable
The viewfinder information will be displayed even during an exposure.
Displays the exposure setting, number of remaining shots, etc., during
continuous shooting.
ffl When the shooting mode is set to “Bulb", even if setting 1 is set, it will not
take effect.
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