As Sony introduces the Alpha a5100 interchangeable lens camera, it officially leaves behind the NEX moniker its mirrorless line originated with. The a5100 picks up where the NEX-5 series leaves off, combining the 24.3 megapixel APS-C CMOS sensor of the a6000 and the more compact footprint of the NEX-5T. The a5100 also inherits many of the a6000's good qualities, including its impressive autofocus system. The a5100 also one-ups its big brother by offering 1080/60p video at 50Mbps. We took a hands-on, preliminary look at the a5100.