Shutter curtain sync

[Tonym]

I took some pics today using AE on my 50D and fiddled with ISO settings and some came out over exposed and some were quite good, the main difference I see is because of the ISO setting, I noticed on the shooting info for shutter curtain sync it said "first curtain sync". I have looked in the 50D book and cant find any info on this so can anyone explain what this is? thanks for any help.

[ameerat42]

"Fisrt curtain" is a flash synchronisation setting, where the flash fires immediately the shutter curtain opens. "Second curtain sync" is where the flash fires well into the shutter exposure time but before the (shutter) curtain closes. Also in 2nd Curtain sync a short evaluative flash fires before the main flash. It's in the manual in the section about built-in flash". Am.

[Tonym]

thanks Am, I looked everywhere under shutter in the book but not flash