Last night I covered football, at what turned out to be the darkest stadium I've ever shot at. Here is a shot from the Mk IV @ ISO 8000, 1/500th and f/2.8 and the 70-200 mk II.
and one from the Mk III @ ISO6400, 1/400 and f/2.8 using the 400 f/2.8L IS
I don't like to shoot action at less that 1/400th. When I first picked up the Mk IV, I immediately started using it on the 400. But since it has more resolution, I moved it to the 70-200 so I can take advantage of it's higher resolution and ISO, if necessary.
Although, that doesn't help if you let the action get too close to you. Here's the 70-200 at 70mm.
Looks like I'm going to have to back away from the goal line if I want an image I can sell.
McCollum took the win, 38-7