I have seen used lenses for sale that are described as "hand-picked" by Linhof, or whomever, indicating that these lenses meet higher standards than off the she lf versions. Is this practice still in place anywhere? For instance, does Sinar test their rodenstocks, or just engrave the lens hood. I think I read of a lab t hat tested ten apo-sironar S lenses and found 2 that they felt were adequate for thier purposes. Thank you.