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Old October 2nd 04, 04:53 PM
Prometheus
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In article , Jonathan Wilson
writes
On Sat, 2 Oct 2004 11:23:24 +0100, "Len"
wrote:

saw the reference to 2nd. curtain synch. Could you please explain the
difference from 1st curtain?
I keep on seeing these terms mentioned but have never found an explanation
for them.


It means the flash goes off just before the shutter closes, 1st
curtian means the flash is fired just after the shutter opens.

The problem with first curtian is that when there are moving objects
any motion blur is after the initial flash... so if you where shooting
say someone running from left to right they would be frozen by the
flash at the left side then you would see the blur/ghost image of
thier movement to the right... The movement trails/blur should be
behind the frozen person, so it ends up looking wrong.

If you cant picture the above visually, think of a comic book picture
of someone running (say road runner, beep beep, lol) where tbey put
the speed trails behind the person, with first curtain sync they would
have to draw the character with the speed trails in front of the
runner.


But first curtain flash must leave any speed trails behind the moving
subject; ask yourself, how can they be recorded before the shutter is
open.

The problem with first curtain sync is that if your subject *moves in
response* to the flash and there is enough ambient light to record that
movement (as is often the case) it is far better to have that movement
take place when the shutter closes rather than when it has just opened.

--
Ian G8ILZ