Hey there, I recently purchased a speedlight 420ex for my Canon 40D last week. I've been having extreme trouble trying to understand how this is suppose to work with me camera. I remember the first time I hooked it up and turned it on, the flash was working fine and I was able to pull out good shots. But at one point, I had to be dependent on luck for the flash to go off. I don't think there is anything wrong with the flash it self because it turns on fine and the little red lights come up in the back. Zoom meter also works fine. I just don't understand - the camera just doesn't give a flash symbol when I have it hooked up. I've tried all different modes and even tried my friend's 430ex, and I get the same problems. I purchased my 40D last month and it was brand new, so I highly doubt there's anything wrong with that. Are there some functions I need to set in the camera? I went into the menu and enabled flash, but still nothing.. What do I need to do? This is really aggravating me! Any help would be appreciated. Thanks!