Just an FYI, Apple stores are currently unable to fix the ‘half-moon’ issue on 6 and 6 Plus iPhones if you have iOS 9 installed. Apparently the equipment that does this is not ‘updated for iOS 9’, sounds odd, but that was the explanation by the Apple employee at the Genius bar. So, anyone with this issue running iOS 9 will get a replacement phone. This is a good way to refresh your device before the warranty expires and also to fix this issue. Myself personally, I noticed that the ‘half-moon’ was getting larger over time, essentially closing off the lens like a camera aperture.