Limited AF selection with 100-400 v.II + 1.4xTC MkIII on a 5D MkIII

I grabbed my new 100-400 v.II and 5D3 and went out to play this morning.

I discovered something I did not expect. When shooting with the native lens on the 5D3, all AF selection options were available.... single point, zone, expanded, spot, all points, etc..

HOWEVER.... when I mounted my 1.4xTC MkIII between the body and lens I only had 3 choices available..... single point center, spot and single point expanded (1 left, 1 right, 1 up, 1 down). I was shooting in AI Servo and never thought to check other settings at the time.

Has anyone else experienced this? If so, have you found a way to access all selections?

Harvey_G wrote in post #17341767
Has anyone else experienced this? If so, have you found a way to access all selections?

At f/8, only the very few center points in the 5D3 work at all, so the servo options you cannot select would make no sense anyway. The center, cross type point is the only one that can be selected and the four points around it act as assist points. That's it. All other AF points are deactivated.

That's why the servo modes cannot be selected, because there is no such thing as 'area' AF when you only have one AF point working.

Although I do not have that camera, it is because the minimum f stop changed to f8.0 at the 400mm end of the zoom. Therefore, only the center AF point will work for focusing. This is the same on the 1DX, 5DIII, and 7DII.

it is normal

Yeah, all lenses + TC focusing at f/8 are category G for AF purposes, and even then they will only work on bodies that allow AF at f/8.

The 100-400 alone is category B.

Prior to 5D3/1Dx on previous 1D bodies you only got the exact center AF point @ f/8
I understand that with 1Dx, 5D3 and 7D2 we get to use expansion and zones now, but still only around the center AF point.

So yes, this is all normal.

Thanks a lot, folks. I guess I should have taken more time to read all of the manual.