# firing the flash at the end of te exposure instead of the beggining...



## nagoshua (Nov 12, 2007)

I've lost the instruction manual to my 430ex flash, im going out to take some photo in town tonight of a friend so ill need a slow shutter for the background and some flash to expose him, question 1, when is it best to fire the flash in this situation? before or after? and question 2, how do i get my flash to fire at the end of the exposure (im guessing its a custom function on the flash or something).


----------



## Big Mike (Nov 12, 2007)

IMO, it's almost always best to fire the flash at the end of the exposure...known as 2nd curtain or rear curtain sync.  This way, any motion blur will show up behind the flashed exposure...and look more natural.

That being said, if you use 2nd curtain sync...there will be a longer time between flashes.  The camera/flash uses a pre-flash for metering...usually this is so fast that it's almost indistinguishable from that actual flash...but when you push the flash to the end of the exposure...the pre-flash still fires before the exposure.  This may cause your subjects to think that the first flash is the real flash and turn away...or it may cause them to blink etc.

I'm pretty sure you can set 2nd curtain sync on either the camera or the flash.  I'm not sure which will be the overriding control...the camera I think.
It's one of the custom functions in your camera's menu.


----------



## Jeff Canes (Nov 12, 2007)

Did you check the Canon site to see if you can download the manual


----------



## nagoshua (Nov 12, 2007)

i thought it was that, i tried it and the flash still fired at the beggining, turns out i have to set it on both camera and flash, problem is, i dont know which custom function on the flash it is!!


----------



## Big Mike (Nov 12, 2007)

From HERE


> *Enabling second curtain sync. *
> 
> This depends very much on the camera and flash unit that you&#8217;re using. Early on, Canon put control for this feature on the flash unit. Later they switched to putting control for this feature on the camera body. So whether you have second-curtain sync available to you depends on a complicated set of permutations.
> 
> ...


----------



## nossie (Nov 12, 2007)

Kudos to Big Mike for doing the research work.


----------



## Big Mike (Nov 14, 2007)

That is from what is commonly referred to as 'The EOS Flash Bible'.  It's a lot of reading, much of which is rather technical...but all the info is in there, somewhere.


----------

