Focus testing

My RX10IV can produce fantastic results. But it also seems to miss focus sometimes even with apparently simple subjects like perched birds. This could of course be technique on my part. I thought of getting it professionally checked out but the quote for that at the official Sony place is in excess of $400 and that’s before anything is even repaired. I want to do some controlled testing. I’m going to set up some tripods with stuffed animals and such for static but how would folks go about testing focus for moving subject? My first thought is to tie a stuffed animal to a rope and hang from a tree and have is swing around. Looking for ideas.

I don't shoot the same Sony model as you, so I can't comment on the specific behavor of the RX10IV.

However the most common issues with missed (or apparently missed) focus that I've encountered are:

1. When there's an object such as a leaf or twig close to the bird (or other focus object) that's throwing the AF off. This happened sometimes with several Sony models, though they seem to have improved it with each new generation...

2. Small amounts of camera movement, or shooting before IBIS has "settled" after moving the camera can produce slight motion blur that is eqasy to mistake for missed focus.

Not sure how applicable either of these are to the shots where you're having this problem. But they are things to consider first before worrying about an AF or IBIS fault...

Thanks for getting back. I would put both of these into the “user error” category. That can certainly be what it is. That or something similar. AF issues are so hard to isolate from user error especially tracking focus. That’s why I’m looking for controlled test strategy. I’ve seen one YouTuber use an electric train. I may have to get something like that.

Take a look the spreadsheet already posted here and see if your settings match........Don

dprevived.com/t/rx10-iv-spreadsheet-again/173/