John Pane

And here is the same test with an adapted EF lens and IBIS off. No issue observed.

I was unable to reproduce this with camera on tripod, IS/IBIS on, shot remotely using camera connect, focused on the arm of the char.

No, it is not.

The RF24-105 does not approach the RF800 in corner sharpness (900 lines at 24m and 1300 lines at 105mm). Is its AF range not restricted?

Let's assume for a moment that Canon is setting the AF range lens-by-lens based on corner sharpness at full aperture at the longest focal length. Here I use sharpness ratings reported by ...

Thank you for these thoughts. If I am correctly understanding, you seem to be saying that Canon has set generic AF range parameters not tied to a specific lens, f-stop or focal length. On what ...

I posted some conjectures in my OP, but I came here to see if anyone had a strong theoretical explanation. Yours would be great if it was supported by the data.

To reiterate, the lens with the 2x TC has the bigger, desirable AF region. And at f/14!. The comparison is being made to the RF800 at f/11 without a teleconverter. According to metrics at ...

Yes, I concede the point that this is still better than old technology. My questions still stand.

Is there a likely technical reason why the R5 autofocus region is smaller at f/11 with the RF800 than it is at f/14 with the RF100-500 combined with Extender RF 2x? In another thread @JayLT4 said, ...

When you all say mechanical are you also including EFCS?

I think this confirms that something is wrong with the reader.

What is reported by System Information (first item in Apple menu when option is held down)? With no cards inserted in the reader, it should look something like this:

Indeed, with the RF 800 the AF area is more restrictive, sometimes posing challenges tracking the eye of an animal that occupies a large part of the frame. I thought this would be dictated by ...

How large is the autofocus region at f/14?

Sorry Carlos, it has already been sold. See the post directly above yours. Best, John

There is discussion here of shipping delays: https://www.cpricewatch.com/blog/2020/12/whats-going-on-with-the-canon-direct-store-sale-ends-on-thursday/