Recording is at 10-bit 4:2:2 quality, in ProRes or DNxHD, directly onto HDD or SSD drives. Input and output are both by HDMI and an optional converter can be used to capture by SDI. Various serial control options include managing multiple Ninjas via an iPad over the web.
Designed compact and robust, and affording a workflow beyond just capture and output, Ninja can serve companion-like on and off the set. Also noteworthy is the Atomos history. Atomos recorders were used, for example, in James Cameron's Deep Sea Challenge.
Ninja comes packaged in a tough carrying case with a bunch of accessories including two batteries and two SDD/HDD enclosures.