Help educate me on external flash and sync speeds!

So, I've got a couple of flashes (Vivtar 243, and Sunpak 383) and a 400D. I tried taking some shots today of some local skateboarders at their park, mainly just experimenting with fill flash.

My question is though, how do sync speeds work, is the max 1/200th because of my camera, or is max sync speed because of the flash? I'd love to have a high sync speed for when I'm shooting in Av and my shutter can fluctuate from 1/250 to 1/4000 pretty easily.

Is there some place I can find this info explained easily?

Nice explanation in this Youtube video..

http://www.youtube.com …n5nzPvoIM&featu​re=related

Camera generally. Some radio triggering devices take a little while to process the signal, so they may slow the sync speed a little more.

With regard to the Youtube video, modern shutters usually move vertically rather than horizontally, so the dark area will be across the long axis of the picture rather than across the short axis.

Thanks for the video. I understand how the curtians work, and what sync is but what about the insane sync speeds I see all over the place?

I keep seeing "1/8000th sync speed" on flashes, or hear people talking about syncing their cameras at like 640 plus. Am I just completely misunderstanding them or something?

Basicly I'm looking to use a flash for some fill on sports and fast moving stuff. But how to people accomplish this if a camera can only sync at say 1/250th?

Only the dedicated Canon EX flashes can do high speed sync. Hit Google, this article shows up first...

http://www.rpphoto.com​/howto/view.asp?articl​eID=1026

Lotto wrote in post #5634414
Only the dedicated Canon EX flashes can do high speed sync. Hit Google, this article shows up first...

http://www.rpphoto.com​/howto/view.asp?articl​eID=1026

LOL, I just got done reading that article.

Things are making more sense now.

So basicly the only way to get a high sync speed is to buy a 580EX or the like?

Yes. Well, Nikon and Sony have their own HSS system too.

You know I have the 580 exII, and never realized what High speed sync was. I guess I could have read my owners manual and figured it out. Flash is still very new to me, but hopefully I will be a little better now that I read that article. Thanks for that, it was a huge help.
Dave