Night Games

I do mostly portrait photography, but I am doing more and more youth sports. I recently bought a Canon 5D MarkIII. I had never shot a full frame before, so I did not relize how much range I was losing. for baseball My 70-200 2.8 could cover all the infield and I would use a 300 F/4 for the out field, on a canon 50D. If it was a night game I was stuck with my 2.8 for the whole game. I can't aford a 400 2/.8 lens at this point. if I by a 400 F/5.6 and a 1.4X teleconverter to use on the 70-200. will the 5D Mark III beable to shoot the night games.

I've never used that particular combo, but I'll bite. On the plus side, that 5DMIII is going to have excellent high ISO capability. In a decently lit stadium, I have no qualms shooting with an f/4 lens, and I have done the f/4 with 1.4 tele (so f/5.6) around sunset without a problem, and that's a 5DMII. Without the teleconverter, I'd say you'd be fine. . .with, you might be stretching it, depending on how good the MIII is at really high ISOs.

Hopefully, someone with a bit more relavent experience will pipe up for you, though.