I recently got a new enlarger that can do 6x7 negatives and it came with a 135mm lens. I previously had a 35mm enlarger with a 50mm lens, but I find that the 135mm lens does not make a very big print with 6x7, approximately only 8x10 (i have beseler 45mx2) and the 50mm lens the corners are not getting any light with a 6x7 negative. Is the 50mm lens too wide? What sort of lens would be good to get up to 16x20 on this enlarger? Can anyone reccomend a specific lens that is reasonable quality. Thanks.