According to Apple Insider, which reportedly obtained a research note from KGI Securities, analyst Ming-Chi Kuo says that only the 5.5-inch iPhone 6 will use optical image stabilization (OIS) for its rear camera. Apparently, the 4.7-inch iPhone 6 model will feature a “middle-mount open-loop voice coil motor” instead, which should be an upgraded mechanism of the one found inside the iPhone 5s. It’s said that Apple is forced to use OIS on only one of its new iPhones because of supply constraints.