graeme wrote:Thanks for the tips John. Pretty much as I'd planned. I also shoot panning shots on continuous (as I'm sure most do) and the middle shots are, in theory, a bit sharper without any finger movement on the shutter release. Press a bit early, then keep tracking, then release late, then throw the first and last shots of the group away without even inspecting them. That's more habit than lab-tested advice though.
I haven't pointed the 100-400 at anything faster than a duck yet. Waddington airshow this weekend will be the real test of the zoom and focusing. Worryingly I think it'll be mostly hand-held... I anticipate sore muscles.
I'm sure the 70-200 f/4 is probably better value than the f/2.8 for motorsport anyway. I'd be tempted to pay the extra if I shot football or indoors, but at the track I can't see it getting used wide open very often. Evenings maybe...
I just tend to take a single shot when panning, but do get a lot of poor ones which I just discard in camera and wait fo them to come round again

. The 2.8 would be ideal for lower light conditions like we had on Saturday, and would allow me to use a lower ISO if used wide open. The good thing about the 2.8 is that you can use the 1.4x convertor with it to good effect, giving you an extended range without the need to lug a bigger lens with you.
The Sigma 120-300 2.8 is supposed to be a superb motorsport lens, but it's close to £2k new so well outside my price range!