Hello! First, thank you for giving an objective, thought-out response free of sarcasm or patronization; I appreciate that.
Yes, I definitely explored the AF customizations. Some more features I might have preferred would be tracking sensitivity settings, accel/decel adjustments, AF point switching thresholds, etc. That being said, all the properties I'm naming are typical of high-level sports bodies, and I don't expect that in this camera, of course; my point was more that I felt I could have improved my keeper rate with some adjustments.
I definitely don't think the AF-C is pretty much useless — far from it. As I mentioned at the end of that section, things improved quite a bit when the horses slowed to a walk, and that's promising for the wedding crowd. My point was more that I held this camera in about the same range as the 5D Mark III and the D810, and it was lagging behind those, but perhaps that got a little lost in my final writeup. DPReview was definitely very harsh on the autofocus; I don't think it's that bad. What concerned me (and perhaps I could have expressed more clearly) was that in the lateral test, there were no challenges to AF system: I had a clear line of view to the horse, there were no obstructions in between, etc.
In reading the comments on here in response to my review as well as the general user experience with these cameras, I think one thing is becoming clear: Pentax needs to improve their manual. It contains very little information on the AF system and speaks nothing of the scenarios in which certain settings are appropriate, etc. Furthermore, the descriptions of certain functions in the manual are not what many users have claimed them to be. As we all know, modern AF systems are both complex and proprietary, and getting the most of them requires an intimate understanding of them, so it's prudent that a camera company sufficiently detail their function, particularly if, as you mention, some choices might be unintuitive. And yes, normally, I would simply pre-focus on the jump in question; I was just using this as a further test of the AF system's ability to handle approaching subjects.
Yes, I mentioned that one can switch the behavior of the directional pad to be an AF controller first; nonetheless, I would prefer a dedicated controller so I don't lose immediate access to those functions, or even better, a joystick, as I tend to switch AF points very quickly. But that's just a difference in personal preference and shooting styles. Some people prefer the directional pad, and there's nothing wrong with that.
As for the green button, it's definitely possible I could appreciate it more, but it's just my personal preference to have an AF joystick there. I felt that the camera has such a plethora of controls that at that point, it would have been better served by having an AF joystick there (perhaps the green button function could be the default behavior of a custom function button). Again, though, that's personal preference, and I probably place an above-average demand and priority on AF performance and usability. The scenarios you mention are absolutely cases in which it's highly useful and convenient, so if that's what one prioritizes, then it's great to have there.
Anyway, as you noticed, I did love the camera. Frankly, if I had some income to spare, I would pick one up, ditch my landscape-oriented Canon equipment, and use this for that kind of work, keeping the Canon for other stuff. But for me, it makes sense to stick with one system, especially because I'm heavily invested in it. If I were just starting out or making my first upgrade to full frame, I would take a long look at the K-1. It's a fantastic camera that was a joy to use, and it was refreshing to use a camera of that capability at that price point; that alone is huge. And let me just reiterate: I don't think the AF-C is useless; if you gave me the Pentax and told me that was now my wedding camera, I could still do my job just fine. Perhaps what I was trying to express more so was my disappointment that it wasn't of a higher level, because it would be a great thing to be able to say: "Look at this camera that competes with the big companies on every level, adds these unique and awesome features, and completely undercuts their prices." The K-1 is on the cusp of being that camera that could shake up the industry and drive the whole of innovation forward, and I think that's something we would all love to see, no matter what we shoot.
