I'm using a Sigma 18-50 f2.8 EX glass (great glass). There is no "auto" selection on this lens.
These next two shots are the same as before, but no lightsphere and straight on to the target (obvious heavy flash in the first).
Fist shot - Manual - ISO 200 - f4.0 - T1/30 - flash on AUTO w/ matching iso and f stop
Second shot is exactly the same except PTTL.
This has been my experience with these flashes for a year and a half (the 540 has been back to the factory twice). All the adjustments on these shots below are zeroed (flash and camera +/- = 0). To use the flash I usually have to bump the flash to +1.0 and the camera to +2.0, even then it is marginal for anything further away than 6 feet. In software it usually requires one more F stop push to get a good exposure for a total of four full stops underexposed..... sigh.. If I didn't have such a good arsenal of lenses already, I really would consider the big "N" switch.... the ledge... there it is...
Thanks, folks.