It a Little Strange but over the Years i have Come to this personal "fact" its a matter of temper (Zeiss, rodenstock) never worked for me (Essilor, Shamir never problems) there is a reason that some peopel swear to a specifik brand, they have all been around for a long time, so they all know how to make lenses and if one of them was better than the other we would know. there for i must conclude that it is a matter of temper.