I want to enlarge my 4x5 negatives to 16 x 20. I don't have a lens board that will fit my Nikor 150mm lens so I used my Nikor 135mm and two durst 240 condensors. The 135 just does'nt quite give me enough coverage at 16 x 20. Being that it does not seem that Durst makes a lens board with a 50mm thread i'm thinking about sending an extra lens board and my 150 mm Nikor to SK Grimes and let them fit my 150 lens to the board. But, before I go to the trouble to have my 150 fitted, is the lens I should be using ? I'm not above buying a new 150mm Schneider and having that fitted if the Schneider will be a batter lens in the long run If I'm going to have this done I want to do it with a very good lens.