This lens should be the same lens as the Meyer-Optik Trioplan 100mm f2.8.
Anyways, took some shots with it today and sure enough, most of the pictures came out hazy, especially those shot against strong lights. But, some level/contrast adjustments brings back some usable pictures. But I guess I will be stuck with shooting at open apertures for a while. Even at f2.8, the lens is very usable and quite sharp. But the lens can not see any side light or strong lights, or it will become hazy. I think a functional and clean version of this lens would be quite a nice lens to shoot with.
Crab Apples - Sony NEX-5N & Pentacon 100mm f2.8 M42 Mount