Originally Posted by melander 
So very very strange, I removed my UV filter and now it seems like it can focus better. It dont stop and try to focus past the limit anymore. And my UV filter is clean as it was when It came out of the box. Hmm, need to investigate further
Hopefully it was one of those cheap ones "just to protect the front element".
I'll reference this thread next time someone asks why hoods are better at protecting lenses than cheap filter.