now let me preface this by saying, I am not blaming the equipment, but I don't understand what exactly the problem is. I have shot airshows (and EAA) many many times with an XT, XTi, 40D and 50D, all with a 100-400. I have never had this type of noise before. Here are links to 2 pictures that are typical of 99% of my shots from today. There are some that are ok, but few and far between. I used all metering patterns thinking that was the issue, but didnt seem to matter. I used AV and TV modes and AI Servo. Again, I am sure that there is something that related to me shooting and not the gear I just don't understand what it is. These pics look like they were taken with a 75-300 and not a 100-400.
1/320, ISO 200, f7.1, AV mode, 250mm
1/640, ISO 200, F11, TV mode, 100mm
Is the camera simply underexposing? I do not have any EC. Pics taken at ISO 100 look identical.