I think that the 105mm is considered the proper lens for 6x9 but lets say I decide to get just the 150mm I think the limitation will be the max size print I can make. Any other issues? How much will I miss out in terms of size? Looking at the beseller website it claims a 5x enlargerment is possible with a 150mm lens and a 4x5 neg. If I could get that with the 6x9 that would be more then enough. Is it reasonable to assume I'll get the same 5x enlargerment by just changing the negative size?