Originally posted by ThorSanchez I would have used it in the past with my K-30 and K-3 II if it worked. But my experience after thousands of sports photos was that center point was much better. The Mark III is my first camera with truly functional tracking autofocus.
I think it's important to understand our gear.
I have *never* had problem with Expanded Area focus on my K-1, which will be the same as the K-3 II. It is truly functional, that is how that triathlete's picture was taken in Post 9, below is another. They are centre point Expanded Area, since they are moving irregularly and I am panning, it is unlikely that I (or you) could keep focus on exactly the same line on their costume during those movements. That's where Expanded Area comes in, when centre point strays off the central zipper, the camera doesn't hunt attempting to reacquire focus with a non-existent edge underneath it, instead a neighbouring AF point recognises and follows the zipper.
By contrast, the K-30 does not have the 86,000 pixel RGB metering sensor of the K-3 II so has no pattern recognition.
You can understand that in referring to p62 of your K-3 III manual (I have downloaded it), the K-30 has de facto "Type 2: Tracks AF points using AF sensor information only."
The K-3 II has "Type 1: Tracks AF points using AF sensor and AE sensor information."
Note that the Nikon D500 has a 180,000 pixel metering sensor.
The K-3 III in fact has 307,000 pixels for its algorithms to use.