Hi, Having Mamiya RBproS for two months for now, times comes for print making. Now, I have 80mm lenses (Schneider Componon-S, Rodenstock Rodagon, and Meopta Anaret). I also have colour head for my Meopta Magnifax 4 enlarger, I use that head for multicontrast papers. I also have mixing chambers for 24x35mm, 6x6cm, 6x7cm and 6x9cm negatives. And also apropriate condenzor lenses for b/w head for graded papers. But I don't have 90mm enlarger lens. So, question is: Will I have any problems (sharpness problems, distorzion problems, light falls or magnification problems) if I use 6x7cm mixing chamber, or apropriate condenzor lenses, with 80mm lens for 6x7cm negatives? Or, asked other way, must I buy 90mm enlarger lens for 6x7cm negatives? Note: For example Rodenstock even don't have 90mm lens in Rodagon line. They in theire catalogue state that theire Rodagon 80mm is for 6x7cm negative size. On the other hand in ApoRodagon line they have 90mm lens, and Schneider also have 90mm Componon-S lens. So, again, 80mm enlarger lens for 6x7cm negative. OK or not? Thank you and regards.