Having trouble focusing on Moon Is there a way to adjust the manual focus sensitivity on a lens?

[d5heilman]

I am using a 5D Mark 4 with a 70-200mm f/2.8L ii and a 2x iii teleconverter to take Moon photos. The problem I am facing is Autofocus is not accurate enough at that range, and when trying to focus manually it is way too sensitive. I turn the manual focus ring the absolute smallest amount I can and the focus point overshoots my target by miles (literally miles). Is there anyway I can adjust how sensitive the manual focus ring is? Or any other ideas I could try?

[d5heilman]

I don't think it is the tripod, yes it shakes a little while I am manually adjusting focus. I was using the 10x zoom to do the adjustments, but the tiniest adjustment would move the focus plane so quickly, even at f11. I am beginning to think it might just be some Haze between me and the moon that may just be the problem, but I still don't understand why the focus plane is so narrow and moves so quickly at f11, I thought it should be pretty deep focus at that distance. Here is my final result. 

[ebiggs1]

Seeing conditions are the number 1 priority.  There is even a scale to rate it.

"...yes it shakes a little..."

Not good. Even a tiny shake will show up most of the time.  Even a slight breeze on the tripod can effect sharpness.

Your Moon shot is pretty nice so I think you are getting the idea OK.

[RobertTheFat]

Forgive me if this point has already been raised, but I wonder if it could be part of your problem. A lens designed for autofocus is usually capable of focusing beyond infinity. (This keeps it from banging on the stop if it temporarily overshoots the target.) But as others have pointed out, autofocus doesn't work very well on the Moon because of its lack of contrast. But if you switch to manual focus and then accidentally overshoot the infinity point, the picture will be OOF at any aperture. A common way to deal with that is to focus on an object (a tree or building, for example) that is far enough away to be within the hyperfocal range of infinity at the chosen aperture, then leave it there as you switch to manual focus and point the camera at the Moon.

[Waddizzle]

“I don't think it is the tripod, yes it shakes a little while I am manually adjusting focus. I was using the 10x zoom to do the adjustments, but the tiniest adjustment would move the focus plane so quickly, even at f11. I am beginning to think it might just be some Haze between me and the moon that may just be the problem, but I still don't understand why the focus plane is so narrow and moves so quickly at f11, I thought it should be pretty deep focus at that distance. Here is my final result. “

Yes, the tripod cannot be ruled out. If you have not already done so, lower the center column all the way down.

As for how sensitive it is to focus, I would suspect it could be a consequence of the extender. Try focusing on a bright star. It might be better.