Hi! I'm very new to SLR photography. I've read several books on photography and feel that I understand the relationship between ISO, shutter speed, and aperture. I recent got a Canon XTi and so far have been pleased with it. Though, the more I learn, the more questions I have Anyways, over the weekend I was at a party inside a resturant and was having problems getting a correct exposure using the in camera flash. I was using aperture priority mode, forced the flash on, and set the camera to ISO 400 and F/4. However, the camera selected too long of a shutter speed and my pictures were overexposed. I think this is because it did not compensate for the flash. So I guess my question is if I'm using the flash in low light, how do I know what shutter speed to select? Thanks!