I have a 6 month old 60D and a 6 year-old 580EXII. I am new to having the AUTO ISO speed, (which I love) but when I set Av to get greater depth of field and use the flash, the camera uses very slow shutter speeds (.5 second and even higher), even with the flash. Looks like it is always setting the ISO at 400. It seems to work fine in Tv, but may be setting ISO to 400 (I'm going to experiment some more with this), and is resulting in wide apertures (2.8) but good flash exposure. Camera is set to AI Focus (shooting people moving around in a room) and taking high speed continuous shooting. When shooting in P mode, ISO is changing fine when needed.
Should the flash/camera (Auto ISO) be expected to work differently than it is in Av Mode? My intuition is yes. I need a medium high depth of field to shoot indoor gatherings and when set in P mode I get low depth of field, usually 4.0 or 2.8. Could I have inadvertently set something in the camera that is causing this? How can I trouble shoot whether it is the camera or the flash? Flash seems to work fine otherwise. Flash has been lightly used through its life and never abused. I do not mess with the flash modes or settings yet, but could some setting there be causing a problem? Thanks for help! I bought the camera because of some important family gatherings coming up in the fall and have been practicing but need to figure this out. Unfortunately I don't have access to a different flash or camera to help troubleshoot this.