I've never used Auto ISO before the 7D, so it has been a delightful surprise for me that it works so well. Someone on the dpreview Canon forum that includes the 7D asked if I'd ever used Auto ISO with manual mode and I had to admit I hadn't. At first I tried it with my 40D because I had the lens I needed on that camera. In auto ISO the ISO wouldn't go above 400. I switched lenses and tried the same settings with the 7D and they worked like a charm, but I didn't want to get down on my hands and knees to get this shot so I switched to Live View, which I absolutely LOVE on the 7D. The shutter click is so quiet! No noise reduction on this shot, taken with the light from wide spectrum fluorescents in my ceiling. By the way, I thought I was grabbing the 17-55 lens because it's good in low light, but it turns out it was my 10-22. The high ISO is so good on the 7D that the f stop was no problem. Observation: This is a situation in which Auto ISO can work well. May not work as well in a heavily backlit scenario. Exposure Compensation is not possible in full manual mode, so with a backlit situation you're probably better off with Manual ISO.