What is dual gain and how does it work?

The Panasonic Lumix DC-GH6 has a 'dual gain' sensor, but not in the sense you're likely to have encountered before. The Panasonic GH6 features a mode called Dynamic Range Boost which the company says is based on a sensor that features 'dual output gain.' This mode is always engaged in stills shooting mode, making it the first time we've seen dual output gain on a stills camera. Given the widespread adoptions of the similar-sounding 'dual gain' sensor design, we thought this would be a good time ...