Dickel, I understand you are going for low-key portraits...And you can do them all you want..But when using flash for portraits of people in general..You want to expose for the ambient light first, then add in your flash to balance it with the ambient...I know you may not want to show clutter in the background, but if you have fast glass you can shoot wide open and use flash on lowest power for fill..Remember shutter speed controls ambient light ...