The bad news is that some iPhone 6 Plus cameras are producing blurry photographs, and yours may be included. The good news is that Apple is replacing defective cameras free of charge. You can go to any Apple Authorized Service Provider or Apple Retail Store to have the defective device replaced.
You do need to verify that your unit qualifies for the exercise though. Visit the iSight Camera Replacement Program for iPhone 6 Plus page for all the details.