I had the chance to print a few 16x20's from some 35mm negs, and I'm wondering if I've hit the wall with my enlarging lens, a decades-old El-Nikkor 50/2.8. First, I thought it was my camera lens: one side of the frame was acceptably sharp (not great, just acceptable) and the opposite side was soft. I quickly realized that the grain itself was soft, hence the soft image. Focusing for sharpness on the right side threw out the left, and vice-versa, and the middle was never sharp when the edges were. I suspected that my decades-old Beseler 23C was out of true, so I fiddled with the lens assembly at the bottom of the bellows, shifting left and right with limited improvement. Sorry I'm being so long-winded here, but could I have a bum enlarging lens? A close exam shows haze and other crap in the lens, but I never noticed any trouble at 8x10 printing, so I ignored it. Does 16x20 bring out all the flaws that have been lurking all this time? And on a related note, does an enlarging lens have depth-of-field like a camera lens? If I stop down to f8, say, do I get better d-o-f and sharper grain, even if my eyeballed focus is off? Thank you for your help. My Rodenstock Omegaron 75 does not seem to have similar difficulties...or if it does, the smaller enlarging ratio disguises it better at 16x20.