The design of log curve

Jason Zhang, Founder & Chairman of Z CAM regularly posts on Medium, here is his latest article on what he thinks about log curve:
There are a lot of popular tutorial on how to expose with which camera on Youtube and all kinds of review websites. Long time ago before I learned all necessary things I’ve seen massive similar articles and video tutorials. The more I read and the more confusion I had. There are a lot of “Should” but nobody explains “why” so it becomes a mysterious topic and then people invented ETTR.
I come from the camera side and learned post process from scratch. So I tried to understand every step of the process and then come back to camera to design the curve.
Continue here.