I've been happily using my G2 with Canon's Speedlight 220EX for some time now, when all of a sudden it doesn't appear to be working properly with the camera. In aperture priority at F2.2 (for example) it chooses a shutter speed of 1/6, so that when the flash fires the entire scene is whited-out. The flash is firing but the camera is ignoring it, and the E-TTL light on the back of the flash isn't lighting when I focus.
It's probably some stupid setting change I made accidently, but I think I've been through everything..Any ideas?

