Sorry to see that you have experienced this back focus problem. I have shot many pics with mine in combination with my 18-300 without any problems. My first experience was in Costa Rica where I put this camera and lens through a wide variety of conditions and it came out smelling like roses. I used just about any focus combination that the camera can offer and I was amazed with the accuracy. I have plenty to see in my website showing the quality and great performance of this camera.