Sony has really brought their "A-game" to the mirrorless camera category! The Sony NEX series of cameras are simply amazing. Their compact size and light weight makes them easier to carry and use for long periods of time, and there is no image quality compromise! The NEX series cameras use Sony E mount lenses.
Sony NEX Mirrorless Digital Cameras:
NEX-3, NEX-C3, NEX-5, NEX-5N