Continuous focus raptor photography

[Michael Ryan]

I realize that with the Extender on the 100 400 lens on the a7rv that it can be difficult to focus on moving birds. I was at Raptor free fly to the Sonora Desert Museum yesterday and noticed that I cannot use compensation that is  negative compensation with moving Birds or even stationary Birds because it will not focus on them. Wondering if anyone else is having this problem. Positive compensation seems to improve my focusing.

Settings:  the 100 400 lens with 1.4 extender, continuous focus, and ISO Auto 100 to 6400 minimum shutter speed 1/4000. F8. Most of the time shooting at 560 mm.  Auto focus at various responses under bird recognition. {no clear winner there}, focus area wide or center { tracking modes don't seem to work very well on this camera for moving raptors.}. Shutter high +, compressed raw or mid lossless compression { which is fairly useless because it slows down the shutter  rate too much}