My iPhone 5 had a pretty big fault. Occasionally, in either video of photo mode, the back camera would generate large distorted purple lines. There didn't seem to be any pattern or indication as to why these were appearing, but they sure ruined a lot of my photos and videos. This was especially annoying when these photos or videos were of some of Lila's early defining moments. Here's what it looked like.
I couldn't find many posts about this issue at all. There seem to be a lot of quite similar issues with the iPhone 5 camera, but none were my exact issue, so I wanted to post in case it helps others get answers.
I booked a Genius appointment at my local store. I arrived a few minutes early, was attended to on time, and left a few minutes later with a brand new phone. I'd backed everything up beforehand, so all I had to do was erase my old phone in the store, hand it to them in exchange for the new phone, then restore my crucial info from my iCloud backup. I did a full restore from my MacBook when I got home. The whole process was quick and flawless, so well done Apple.
So if you have the same problem, and you're still under warranty or AppleCare, with my experience you should be fine getting a replacement.