I have an OMD EM5 and have set most of the settings to those suggested in the OMD thread.
I have noticed that the camera meters very well when not using the flash. However, when using the supplied flash for land photography or the YS D1 strobes underwater or on land that the photos are 2-3 F stops darker. I have the flash compensation set to 0 so that should not be the problem. This occurs in all metering modes (spot, center and pattern) and in P or auto mode.
Any ideas what could be causing this issue?