...As on the 650D in Live View and video mode, the Canon EOS M uses the new hybrid autofocusing system. This means that it enjoys the benefits of both phase detection and contrast detection autofocusing.

...One of the biggest areas for debate has been what size sensor Canon would use for its CSC. Well, now the Canon M is here and it comes with the exact same sensor as found in the Canon 650D DSLR. That is, it's an 18.1 million pixel APS-C format device.

http://www.techradar.com/news/photography-video-capture/cameras/canon-eos-m-10-things-you-need-to-know-1089701