First real chance to do a head to head with the A1 and Z9. Really difficult event shooting boxing with horrible flickering LEDs. There was another photographer there and she said she had a Z8 but not using it as it was too complicated and she hadn't learned it yet. She gave me a loan of the Tamron 35-150 so I could shoot a native, albeit 3rd party, fast lens head to head with the A1 instead of using the megadap.
The first thing that was obvious was the screens on the Z9 were flicker free. The A1s were horrible, flickering away like crazy. You could get rid of most of it my taking off the exposure preview but it was still there. Focus wise the Z9 was in auto area so it decided what to focus on. It pretty much grabbed the head or eye of the boxer facing me instantly and that was in the auto subject detection. Most of the bouts were with headguards and the A1 struggled to see the eyes and I shot in medium box with tracking placing the box on the head and tracking from there. Far harder shooting with the A1 but in the end I don't think there was a great deal of difference in terms of AF despite the different techniques. One huge difference was the amount of clean images without the darkness caused by the flickering lights. The Z9 destroyed the A1 in this regard and there was only a handful out of 3K that were not usable because of the lighting. The A1 had lots of images where the dark band was evident. Not even sure I even had anti flicker turned on with the Z9. Comparing the clean files again the Z9 came out on top. The colours were nicer and the sharpening looked a bit more pleasing. Both cameras were set with a manual Kelvin setting. Nothing wrong with either cameras files though, at least the clean ones. Battery wise the Z9 again destroyed the A1. I used them about equally and the A1 used pretty much a full battery so half capacity in the gripped body. The Z9 just clicked off the first bar so probably 25% capacity used. The Tamron lens was also very useful, focussed fast but the variable aperture meant I had to use auto iso.
If I had a fast lens for the Z9, at a focal length suitable for boxing, and I was asked to do that event again this week I would choose the Z9 in place of the A1. I will almost certainly add a Tamron 35-150 to my lens inventory but will leave it to see what brand I will end up going for in the next 6 months or so. All in all a win for the Nikon but my main use is Rugby and football where there are often lots of faces in the frame so a very different AF challenge. I'll see how the bodies compare in the months to come