@mevlutcan: I'm sorry to hear that you're having some issues with your camera. What were you advised by the engineer when you visited the Support Centre? If they were unable to identify any software or hardware issues, then please try cleaning the rear camera lenses with a clean, dry, microfibre cloth to ensure that there's nothing on the lens that might be reducing the quality of your pictures. When lining up your shots, make sure that there is plenty of light in the scene, and tap on the area you want to focus on until the image becomes crisp and clear. I also recommend checking for any available updates that might include camera performance improvements via Settings > Software Update, or Settings > Biometrics and Security > Security Update.