1DX MKII + 100-400 II + 2X Ext III

Am I hearing this right from Canon that this combo will allow auto-focus up to f8???

As the 1DX would not do that...

1D series can AF at F8 with center point since over a decade.

Didn't the 1DX get a firmware update that allows this in fashion with the previous 1D's?

(Derp, I see a 2X with a F5.6 is actually F11, nothing should officially AF with that via Canon's phase detect that I know of at this time, but contrast detect AF could work, ie, Live View; but F8 is totally possible with the 1D series with phase detect).

Very best,

Not to my knowledge and in the store the 1DX MKII + 100-400 II + 2X EXT III only shows the center point and will not focus?

But according this video he says it will

https://www.youtube.co​m/watch?v=HYPnuDxpn48

about 3:23 in on the video

The 100-400 + 2x TC gives you F11, not F8. That combo won't reliably autofocus on any body. You can attempt to work around it by taping off the pins that report the TC to the body and hope for the best; but it's going to be ridiculously slow to focus even then.

EDIT: Watched the video and I see your confusion now. The video *shows* a 2x TC while he's making that statement, but the important information there is what he SAYS "...a version 3 tele-extender...". He does not specify the 2x, only that he's referring to the v3 TCs overall; following that, you have to look closely at the chart that is shown, which shows the valid combination for the 100-400 is in fact the 1.4x TC rather than the 2x.

For the 100-400II + 1.4x III, I can most definitely confim *that* combination works ok at F8, although it is notably slower than the bare lens. I use that combination on a 7DII when the occasion calls for it, although being limited to center point AF only is sometimes a struggle.

That explains it then the video should have shown the 1.4 extender III not the 2X, but the chart was right so if I decide on this combo I will have to replace my 1.4 extender II with a 1.4 extender III if I want all those extra points?

picworx wrote in post #18532763
That explains it then the video should have shown the 1.4 extender III not the 2X, but the chart was right so if I decide on this combo I will have to replace my 1.4 extender II with a 1.4 extender III if I want all those extra points?

I would presume so; yes. I don't have a 1Dx to verify that on, but that seems to be what is said there.

If you use a 1DX Mark II together with either the EF 100-400 mm f/4.5-5.6L IS USM or the newer EF 100-400 mm f/4.5-5.6L IS II USM, you'll get AF with all 61 AF points.
If you combine this setup with the EF 1.4X extender III, then you'll get the same. AF with all 61 points. This is class F AF for the 1DX Mark II.
However, if you use the EF 1.4X Extender, or the EF 1.4X Extender II, you'll get AF with nine points. This is class J AF with the 1DX Mark II.

As soon as you go to f/8 with the older 1DX, then you get AF with the center point, or center point expanded (four more points). The center point is the only one you can select in such a case.
So while both the 1DX and the 1DX Mark II have f/8 focusing capability, the kind of capability differs significantly.

Thanks for this as I understand then the 2x is out of the equation if you want AF however the question is whether it is worth it to upgrade from a 1.4 II to a 1.4 III I guess it depends on what you shoot and whether the extra points is really worth it? 9 points is sill not bad

There's a noticeable upgrade of image quality between Mark II and Mark III, I've been told. I only have the Mark III, so I can't compare myself.
Using live view, you can get AF even with f/11 as max aperture. Where this way of working is feasible.