Agree with onslow....the only one that's OOF is #3.  It's very likely because the depth of field is sooooo shallow with these lenses.  Focus IS critical....with AF, then you lock, then you move a quarter of an inch and it's OOF!

Focus point on the first image seems to be in the top right corner, behind the flower

To increase your DOF, use aperture settings of F16 or higher if possible.  Also use a tripod to eliminate movement.

Another thought on image #3 is that you may have gone closer to the subject than the lens would allow, resulting in the OOF.

In youth, we learn....with age, we understand.