I had a bit of a play with the Canon 100-400 but I feel it is not the lens for me. I would like to know the general feeling of using a "prime" lens for airshows etc. I use the camera for wildlife (mainly birds) and aircraft photos.
For the canon buffs.........for my 350D I was thinking of getting a Canon 300mm L f/4 IS USM which I tried and liked. if I add a 1.4 coverter it will give me 420mm and still keep all the auto functions but drop 1 stop. Adding a 2.0 converter you loose the auto focus. I was not that keen on the 400mm L although it would be a cheaper option.
All comments wellcomed!