I'm sure many of you know this but it was an Ah Ha moment for me this morning when I was doing some ETTL testing with my Nissin Air system.

HERE is a post I made explaining the setup and how it can be used.

One of the motivations for this testing with the Nissin Air ETTL capabilities is my anticipation that the Godox TT685 TTL speedlite will be arriving before too long and I want to have an understanding about how the Nissin system works so I can compare the two.