Leonard Shepherd wrote:

Here some go once again.

Used in a reasonable way camera AF in all cameras works well.

Some I find fail to recognise the ability of the person behind the viewfinder has a lot to do with how cameras performs.

Most get excellent results, some do not.

I have found over the years those who get poor results have a camera that can instantly take good photos - used reasonably in capable hands.

You don't have to imply so much. If you want you can call me outright incompetent. I don't care, won't report anyone, especially not the master of all Nikon AF modi.

As I have mentioned before I am a Canon shooter as well and I have some Canon sequences from the same fella in the same location as well. I was not aware of the Zf AF issues during the time of catching those photos, therefore I don't have exactly the same setup and thus it will remain comparing apples to pears (which I am fully aware of).
The Canon shots were done with the R8 and the RF 50mm 1.2 (fully open) and slightly slower shutter speeds, which leads to much more light on the sensor and lower ISO values. Neverthless focusing at f1.2 is a diffrent challenge as well. Overall apples to pears but not apples to bananas.

Example 1: Only slow movements, this is actually a burst (I think it was 10fps):

Example 1, I included the hand and the playdoll to show how focus falloff is with the 1.2 lens.

And here just the 100% crop of the eye (similar focus setup, complete frame auto subject detection, servo AF (AF-C).

Example 1, 100% crops

In the whole sequence only two images are slightly out of focus and as I have seen no real sharp areas anywhere else this is probably not a focus issue but actual motion blur. In the last photos the AF jumped from the right to the left eye. During the sequence he actually lifted his hand and pointed at me (foreground object).

Example 2: More subject movement involved and especially a lot of foreground where the AF could potentially latch on.

Example 2: He is grabbing his doll, this is the last image of the sequence shown below

And here the 100% crops, again RF 50mm 1.2 at f/1.2:

Again, out of those images none is on the ear, none is on the nose, none is on the foreground. One is slightly out of focus and 1-2 are not critically sharp. Canon just can.

And this is what slightly shocked me when comparing the results from the Zf to the R8 as the scenarios are even more demanding in the Canon case (face only partially visible as you can see in the Example 2 overview shot).

And btw I have other sequences with other kids as well that exhibit the exact same behavior, but feel free to pick your conclusion:

1. I am fully incompetent
2. I am not compatible with Nikon
3. Nikon is not for convenience shooting
4. Nikon has some catching up to do with the Zf and Z6 III and expeed 7 alone is not the solution (a fast sensor is probably needed)

I really wanted the Zf to be the breakthrough for Nikon with their "lower end" bodies, this is why I bought one even though I hate the ergonomics. I just wanted to be able to use the fantastic glas with a capable body (the RF 50mm 1.8 is a joke for example) + I really don't want to bring the better RF glas with me during vacation (:-D).
As MJ_79 already mentioned there is a lot hype going on surrounding the Zf but so far I can't see this hype reflected in the images I actually get. The R6II/R8 plattform on the other hand is fantastic.

And one additional disclaimer: The actual RAW images / PNG exports when directly opened from my local filesystem showcase the differences between "critically sharp" / "sharp" and "out of focus" better than the uploads. The compression applied on this plattform degrades image quality quite a bit and evens out some of the differences. The same is of course true for both Nikon and Canon examples.