Eric has had experience with these zooms - I've only seen them a few times. There were three - the 75-150, 140-280 and the 60-140. They are big and heavy, and I never gave them a moments thought, until I saw a shoot with the 60-140 which blew me away. I'm not sure what their purpose is or was, kind of "if they can do in 35 mm land, we can do it better in 6x6", but they are part of the larger story of Mandelmann (then head of Schneider and I think Rollei) committing a remarkable set of resources and brain power to making the full lineup of lenses for the system. Dinosaurs, but what wonderful beasts they were.