That sounds like something on the lens (did you remove the plastic cover on the lens?) or a defect in the camera itself. If you removed the plastic, bring the phone in. A defective camera is covered under the warranty. (Make sure everything is backed up - they'll most likely just replace the phone and send it back for repair, to use as a warranty replacement for someone else. [Don't worry about your data - their first step is a factory reset, which wipes off all your data.]) Ask at your local store whether they're a Device Support Center - that's most likely where you'll have to go. (If you just tell them what's wrong, they'll waste your time confirming it, then send you to the DSC, where they'll spend time confirming the complaint too.)
