Why does my slave flash at full power actually seem to darken the image?
The camera (Lumix G1) is set to M-Mode, forced flash at -2, f6, 1/30s. I set my external flash (Nissin Di466 FT) to slave mode "S2" to ignore the first "measure" flash.
I do an experiment with three shots:
1) Slave flash off: Image is medium bright.
2) Slave flash +0.5: Image is brighter
3) Slave flash +1.5: Image is really dark with a red tone
How can this be? Even if the slave flash has missed the right point in time, image 3 should still have the same brightness like image 1, since the camera flash is still on. Am I missing something?
(iExposure is off, and ISO is set to 200).
[Edit: it turned out that on the Di466 "S2" is the mode that does NOT ignore the pre-flash. But I still do not understand the behavior.]