wrote:
I just got a 5D and, so far, I love the camera, but I can't get the
flash to fire before the shutter closes. I did set the Custom function
#15 to "2nd Curtain sync", but it doesn't do the trick. Thinking it
could be a problem with the flash, I asked my friend to try it on his
Nikon D200 and it works fine. What am I doing wrong?

What flash are you using?
On my 580EX, you can easily put it into second curtain synch by pressing a
dedicated button on the flash unit...which toggles through high-speed
synch/second curtain/normal.

NOTE: If you set custom function 14 to second curtain, but leave the flash
unit itself on normal (1st curtain), the flash will OVER-RIDE the custom
function.

The other possibility is that you're being fooled by the E-TTL
pre-flash...which will still fire slightly BEFORE exposure...even during
second curtain synch...followed by the exposure, and actual flash before the
shutter closes.

-Mark²

--
Images (Plus Snaps & Grabs) by Mark² at:
www.pbase.com/markuson