Apple announces the newest iPhone 5C and 5S smartphones. The 5S model features an improved 8MP camera with 1.5um pixels and brighter lens with F2.2 aperture. The sensor is said to be 15% larger in area. A combination of the brighter lens and the larger sensor provides 33% improvement in sensitivity. The 1.5um pixel size is quite unique. I can't recall any standard product with that pixel size. The closest size of 1.54um was used in 2-year old Canon Ixus-120IS camera. It appears that Apple sensor has been custom designed for the company.
In another publication, Sony Mobile explains its claim that its 20.7MP Xperia Z1 camera is best in class: