Hi Greg,
Was it I who said I used the autofocus? Couldn't find it.
When I doing autofocus with my Canon 6D I can only use the inherent autofocus system in Canon camera and auto foucus lenses on Moon and get good results. Other wise I use ATP that control the camera and the focus motor and take photos one by one and compare and analyze them for best focus position. Never tried that method with camera lenses even if some people say it should work. But I can see when I using my Sigma APO lens which is sharp that it's very sensitive to temperature changes.
Here how I focus with Canon and ATP, in this case just manually but with the important temperature compensation:
http://www.astrofriend.eu/astronomy/...tor-focus.html
/Lars