To say that the battery in the third iteration of the Sony A7R series cameras is vastly improved is an understatement. Both the Sony a6500 and the a7RII suffered from incredibly short battery life, whereas the a7RIII does not. 

Through newly improved and more efficient electronics, and a bigger/better battery the a7RIII can shoot for a reasonable amount of time. My lab run-time test plug it at about 2hrs and 45 minutes for a standard interview type shoot in 4K 100mbps in manual focus mode. I will post insight from real world interview situations as they become available. 

Sony NP-FZ100 Battery (2280mAh)

Interview, manual focus: 2hrs 45min
Interview, auto-focus: TBD

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