According to the chatty Taiwan supply chain, production of Apple iPhone 5s and Apple iPhone 5c models are being marred by poor yields of the camera lens module; and while those vendors performing below average weren't mentioned by name, the supply chain gossips said that Largan Precision was the only producer of the part that was turning out above-average yield rates...
Source: http://www.phonearena.com/news/Apple-iPhone-5s-and-Apple-iPhone-5c-production-negatively-affected-by-poor-camera-lens-module-yields_id47509
Source: http://www.phonearena.com/news/Apple-iPhone-5s-and-Apple-iPhone-5c-production-negatively-affected-by-poor-camera-lens-module-yields_id47509