Need help with AV sync speed

on my new 1D Mark II.

On my 5D, I can set the flash sync speed when shooting in Av mode to a fixed 1/200.

On the 1D2, I cannot find where to do this. So I set custom function 3 on the 580exII, and now it shoots at 1/250, but the problem is that all of my shots are coming out COMPLETELY blown out. At ISO 100, it's a good two stops hot and I've already throttled the flash down -1. I was working on it, and changed ISO to 400, and it's a wash of white.

Please help!

Custom function 3 on the 580EX II is FEB auto cancel. Has nothing to do with your problem.

Use manual mode. Set your aperture (just like you do in Av mode). Set your shutter at 1/250 or whatever. Shoot. Adjust FEC to get what you want.

TaDa wrote in post #7241810
on my new 1D Mark II.

On my 5D, I can set the flash sync speed when shooting in Av mode to a fixed 1/200.

On the 1D2, I cannot find where to do this. So I set custom function 3 on the 580exII, and now it shoots at 1/250, but the problem is that all of my shots are coming out COMPLETELY blown out. At ISO 100, it's a good two stops hot and I've already throttled the flash down -1. I was working on it, and changed ISO to 400, and it's a wash of white.

Please help!

If you know that you want your shutter speed to be 1/250 (or 1/200) when you use the flash, why not just switch the camera to manual mode and then set the aperture accordingly? I looked but there doesn't seem to be an equivalent custom function to do that automatically for you on the 1Dmk2.

Main reason that I ask is because I shoot in Av 90% of the time, and there are times that a kid will run into the shadows or something, and I will want to quickly turn on the flash and not worry about the camera metering back too slow of a shutter speed. Guess it cannot be done without switching over to M.

Thanks all