A while back I was asking about how to set auto 5-shot brackets on the 1ds2.
I finally got it with some help from Canon tech via email.
First the camera only communicates via firewire.
Get a firewire cable for your laptop to camera connection, then follow these instructions:
1. Connect the camera to the computer and then start up EOS Utility.
2. Click [Camera Settings/ Remote Shooting]
3. Once the window opens you need to click on the yellow TOOLS button.
4. Click the Exposure 3 tab and then set PF 8 accordingly.

