I shoot M43 and Canon, having moved over from Nikon DX bodies. I haven't tried your combination but suspect it will not work at all, even for manual flash, which should just use the centre pin to fire. I use Yongnuo YN 622C transceivers for off camera flash, these are designed for Canon, but will work with Olympus, Pansonic and Fuji for manual flash. If a YN622C is placed on a Nikon body, the camera body seems to recognise that something is not right as two pins line up and likely does not permit a signal to the centre pin in these circumstances. It's probably better to move the FL-50 on and buy a Nikon dedicated flash which will offer both TTL metering and manual. There are two versions of the FL-50, the plain and older FL-50 and the later FL-50R, the latter will receive optical signals for off camera flash and is more desirable than the non 'R' version.