1DX +2x vs MKIV +1.4x images

[Richard Lane]

Thanks Rick, I was hoping for an easier solution, something like for every 100mm added you will gain 30ft towards the target.

I found this shot from last year with the 2XII @780mm.

Coming in for a Landing!

MKIV 300mm f/2.8L IS +2XII @780mm Uncropped f/7.1 1/1250sec. ISO 320 Handheld. Clipped wing included!

CQ0H8423 by RL One Photography, on Flickr

So, It looks like I should perform the AFMA before I do any further testing on the 1DX.

Humm.... 800mm would be nice?

Thanks for everyones input,
Rich