Why did I choose to buy the Sony A9 Mk1?

[@huwalban]

Most interesting. I too would be interested in how you get on with AF with the Canon lenses and an adapter. I used the Sigma MC-21 adapter to convert from Canon EF to L-mount on my Sigma fpL. On short lenses all OK, but with the 70-200 f/4 L the AF hunted like crazy - but that might be more to do with the fpL's AF more than either the lens or the adapter. It is well documented that the fpL's AF is not the best. Also, I'm encouraged that you noted your knuckles catching on the edge of the lens mount. When I went the the Photography Show in 2021 to research a full-frame system, this was the one "feature" that I just couldn't get passed with the Sony system, and I went back to the Sony stand multiple times to see if I could work around it. I've got long fingers you see, and once scrunched up against the grip I was scraping the side of the lens continually which was a shame because on paper it was the A7Riii which was the top of my options list.

[@ChrisEdgecombePhoto]

They work an absolute treat with later Sony cameras like the A9. Felt like native lenses for static shots and eye detect worked well in c-af. Was just a little too slow for faster moving subjects and c-af doesn't work in video. I only have 3 cheapo EF lenses, the 28-105 f3.5-4.5, the 70-210 F3.5-4.5 and the 50mm f2.5 macro. I didn't find the macro to be as good.