I already made a thread about this, but I really want to get a second opinion before I make the long trek to the nearest camera shop which is nearly an hour ago. My 40D seems to be acting up whenever it comes to taking pictures that aren't wide open. It seems to act fine when I'm taking pictures wide open, but the second I turn it to f/2.0 and take the picture, the camera completely shuts off. The batteries still work and the only way to get it working again is to take out the battery then put it back in. I really don't think it's a battery failure, but if that's it I guess I need to get some new ones. If anyone has any insight into this that would be awesome.