Both flashes on 1/1 = full power and 50mm zoom
Camera on full manual (aperture, exposure, ISO)
Using a 25mm lens on a camera with 1.86x crop factor (GH2 multi aspect sensor on 16:9).
Wanted to know of the "58" on the Yongnou was just advertisement.
...aparently it isn't.
The Metz is 200eur and has all the bells and wistles.
It can do TTL and even wireless slave with Panasonic GH3 (Flash firmware 2.0) and with Olympus cameras.
The Yongou is 60eur, full manual only, very dump but has simple zoom (as opposed to the 460-II).