archer1960 wrote in post #16704767
No, it's the older version. It doesn't happen often, but when I heard that it was also happening with the 150-600, I just figured it was something in the way Tamron reverse engineered the Canon AF system. Just moving the camera to a different subject and back, or changing the zoom level will bring it back to life.
The difference is, at least for those of us with a lens exhibiting this behavior, it isn't "occasionally". It's 100% reproducible; and it's quite odd behavior.
My 18-270 won't do the same thing no matter how hard I try.
That said, when my camera guy gets back from his trip, I'm gonna have him send it to Tamron for a looksee; and see what they say.
EDIT: To be clear, it's when moving suddenly between a near or far target that's in focus, to a target in the opposite direction that is not. This is not failure to acquire and track something like a BiF nor AF failing period.