Make sure that the camera lens is clean. If you need to clean the lens, use a microfiber cloth. If you see dirt or debris inside the lens, take your device to an Apple Retail Store or Authorized Service Provider for more help.
Make sure that there’s nothing blocking the camera lens. If you’re using a case, try removing it.
With iPhone 6 Plus, a metallic case or magnetic lens could interfere with optical image stabilization. If you have a metallic case or magnetic lens attachment, try taking a picture without it. Then compare the quality.
Adjust the focus by tapping on the person or object in the preview screen. You’ll see the screen pulse or briefly go in and out of focus as the camera adjusts. In photo mode, try to stay steady when adjusting the focus. If you move too far in any direction, the camera will automatically refocus to the center. In video mode, you can adjust the focus before you begin recording.
If the color seems too bright, or you see double-exposures of moving objects, make sure that HDR is set to Auto or Off. Tap HDR at the top of the screen to choose a different setting.
If the problem still persists after following the steps listed above then try to check if there are any new software updates available for your phone. You should also consider doing a factory reset and setting up your phone as a new device.
Before restoring your phone
Make sure that you have the latest version of iTunes.
Use iTunes to back up your device. Transfer and sync any additional content to your computer.
If you’re using iOS 6 or later, go to Settings > iCloud and turn off Find My iPhone.
Restoring your phone
Connect your device to your computer using the cable that came with it.
Select your iPhone when it appears in iTunes.
In the Summary panel, click Restore.
Click Restore again to confirm that you want to restore your device to factory settings and delete all data and content. iTunes will download the device software file and restore your device.
After your device is restored to factory settings, it will restart. When it does, you’ll see the “Slide to set up” welcome screen. Follow the steps in the device Setup Assistant.