"Flash Mode 2" was introduced in ocean+α

A Complete Guide to Underwater Photography with a Mirrorless Camera by Jun Shimizu (Part 21)
Mirrorless SLR photography techniques for specific subjects: "Mandarin fish" [Part 1]

Flash Mode 2 was introduced.
The lecture, which covers everything from the ecology of the mandarin fish to specific and detailed camera settings, is a must-see.