That would be me. As I posted earlier in this thread, I've had the same thing happen (loss of contrast) And every time it has been because I screwed up and ended up with more light closer to on-axis than I should have (badly flagged bg lights/too great a differential/etc). Any of the Canon's are more forgiving. With MF, when you screw up, you know you've screwed up.there is another poster showing a similar white lit bg (jumping woman, post 5) that does not show the flaring.
Someone asked earlier if new RZ lenses have better coatings, I don't know. Most of my lenses are 'W' series. I think a couple are older. I've tried to find a guide/web page that talks about all the generations of lenses but I have not succeeded.