Thanks for that. I'm not too demanding of any equipment, it's all easy better than me, I'd just like to be able to focus and shoot moving stuff like motocross/grass track on dull wet days and actually get sharp shots and then portraits of moving subjects inside on winter days - both have caused me problems in the past, and neither of them are particularly demanding. My 100-400 seems soo slow to lock on focus at times. My X-H1 is great in every other way so I guess I may be heading to a dealers at some point to try both out..
My knowledge of Fuji for this sort of thing is limited, so take this for what its worth, but...
The XH-1 has the same AF as the XT-2, and although it's a comparison with birds and not motor sports, it might be worth looking at this to see how it compares with the current XT-3 and XT-4:
A few years ago, our reader Alfredo suggested an idea for an article. Since we test the autofocus performance of many cameras at the same red kite feeding stations, why not publish a list of all the cameras we use with their keeper rate for birds in flight? I liked ... Read more
mirrorlesscomparison.com
I wouldn't take the results too literally, but it’s a useful resource.
Still on birds, there is a user from "another place" who switched from a Nikon D500 to a Fuji XT-3, with the Fuji 100-400, but has now switched to using an adapted (Fringer adaptor) Nikon 500mm pf on his Fuji XT-3. I've seen a few reports about the Fuji 100-400 being a bit slow for action, but equally, moving to a different system, I've heard that the new Olympus OM1 dramatically improves the speed of the older Panasonic 100 - 400 compared to all previous bodies.
It also works the other way round. On the site I've linked to above, his initial tests on the Nikon Z6 gave very poor results (using a Sigma long zoom) a retest with a Nikon lens lifted the Nikon Z6 up to amongst the best cameras (for AF) he had tested.
For me, sports that aren't stopped because of poor weather is one of the few areas where I think a low resolution FF camera has some real benefits over APS. We will need to wait and see the reviews, but I don't think I would be looking at a 40mp APS sensor for motocross in dull weather. If I didn't want to spend the money on the XH-2s, I would seriously look at an XT-3. I will be surprised (albeit pleasantly) if the new XH-2 (40mp) offers any/much noise advantage over the existing XT-3/4 models, and these newer models should also have better AF than your XH-1.
I've really only paid casual attention to these things for Fuji, but for the use you describe, I would be looking at an XT-3 or XT-4, while I saved up for a XH-2s.
As an aside, I think nearly all cameras struggle with AF in very low light, My D500 does with both my 200-500 and 300mm +x1.4 (both at 5.6) with. a noticeable improvement when I use the 300mm at f4, without the TC. I've also seem comparisons of wildlife in dark woodland where a Sony a9 failed to focus at all and a Nikon D6 (maybe a D5, I can't remember) struggled to grab focus. I can't remember the lenses but they were matched in aperture and focal length.
So, as I said, take what I say with an appropriate amount of scepticism, but hopefully some of it might be useful.
