If you have the option.....

.... how you will use it?

I shoot sports, football for about 3 years now, and i am happy so far to do, but i have an issue with sports results i get.

In the past i was using 1D2n with 70-200 2.8IS, later i got 300 2.8IS, and last i got 1DIII, i get the best result from 1D3 with 300, but now i am not sure if the result from my 1D2n as backup is on par, i don't like most results and i get a lot of OOF shots, so what you will do if you are in my place, use 300 with 1D2n and 1D3 with 70-200? I wish i can get another 1D3 or at least 1D4 but this is not possible now, how can i get the best out of my 70-200 then?

I use my 70-200 F/2.8 (non IS) for most sports. My best results come from setting the camera for only 1 focus point and AI Servo.

Might also want to take a look at the Auto Expand C. Fn, 17 I believe. I was having trouble with some of my shots being slightly out of focus. My MK II was set to auto expand and after doing some research here I found that it was causing some OoF frames for people. Changing that setting helped a lot, might be something to look into.

Mike R wrote in post #11407233
I use my 70-200 F/2.8 (non IS) for most sports. My best results come from setting the camera for only 1 focus point and AI Servo.

But i have 300mm, so no comparison here, also i set the camera to 1 center point and AI Servo and still not good shots.

malibubts wrote in post #11409979
Might also want to take a look at the Auto Expand C. Fn, 17 I believe. I was having trouble with some of my shots being slightly out of focus. My MK II was set to auto expand and after doing some research here I found that it was causing some OoF frames for people. Changing that setting helped a lot, might be something to look into.

I am not sure i understand your points, but my C.Fn set at 0 which is Single AF point. I will test my 70-200 on MKIII and see if it will give me different better results, i remember that my 300 was very good on MKII, but i was hoping my 70-200 to perform great on my MKIIn as well, so will see what's wrong.