Originally Posted by
Chexov
Hey Dave, thanks for the tip that my thumb might have caused the glow, but I haven't covered the viewfinder with my thumb in every picture I took. Most of them were actually taken while the viewfinder was not covered.
I have the suspicion that it had something to do with the fact that VR was switched on at my lens during the first long exposure shots. I turned it of somewhere in between, but can't recall when exactly. I could imagine that the slight camera movements during the long exposure shots caused the VR to move whatever it moves, which might have led to a distortion of the incoming light. I'll test this theory tonight and let you know about the result.