100-400 L with a 1.4 TC

[Kayaker72]

Is anyone using this combination? Do you like it? In addition to the autofocus issues (needs to have f/8 to autofocus), I am finding the shots straight out of the 5DIII to be close to or better than those taken with the 1.4 TC. I am wondering if the 1.4 TC doesn't degrade the IQ much of better glass (70-200 IS II, big whites, etc), but does in the 100-400 L.

A few examples of approximately 100% crops (yes, I am pixel peeping). All shots taken from tripod, remote release, manual focused using live view. Took multiple shots and below represents the "best":
A printout of the ISO 12233 chart you can download form cornell university..both images tweaked in LR to increase sharpness, etc taken ~35 ft (10 m):
5DIII only:

5dIII LR4 600x400-0073 by kayaker72, on Flickr

5DIII with 1.4 TC:

5dIII 14x LR4 600x400-0069 by kayaker72, on Flickr

Closer tree (~100 ft or 30 m):
5DIII only:

5DIII 600 400-0092 by kayaker72, on Flickr

5DIII with 1.4 TC:

5DIII 14tc 600 400-0094 by kayaker72, on Flickr

Tree Further away (~150 ft or 45 m):

5DIII 600 400-0097 by kayaker72, on Flickr


5DIII 14tc 600 400-0096 by kayaker72, on Flickr

Thanks,
Brant