I have a great 400 2.8L IS I use for sports and love it with my !D IV's and recently picked up the 1.4 TC III and have not had a chance to do any testing or micro adjusting but looking forward to this combination for wildlife and birds.

Has anyone seen any samples of this combination or the 2.0X III and this lens?

Slowing down over the next month so will do some testing and let you know how it works.

Can't wait to see this setup on the 1DX also.