Apple Inc. AAPL, +3.03% said a component in the iSight camera of its iPhone 6 Plus may fail in a "small percentage" of devices, causing photos to look blurry. The affected units fall into a certain serial-number range, sold primarily between September 2014 and January 2015. Apple said it will replace the camera, located on the back of the device, free of charge, if the phone is producing blurry photos and falls into the eligible number range. The company has provided a page at this website where users can submit their phone's serial number to see if they are eligible. Apple started selling the iPhone 6 and 6 Plus in September 2014. The company boasted more than 74.5 million iPhones sold in its fiscal first quarter, which ran from October through December 27. Shares of Apple fell 6.4% in premarket trade, falling below $100 and putting the stock on course to open at its lowest level since Oct. 20, 2014.