I know I'm asking a lot of enlarging questions on this forum, but I guess there's no other way to learn in this day and age. So, please bear with me as I ask another one... So, I have a Beseler 23C (the old blue industrial-style enlarger) and I just replaced the (very crappy) Beslar 50mm lens with a Nikkor f/2.8 N 50mm lens. The good news is that now my images are a lot sharper! However, it seems like my maximum print size is only going to be an 8x10. This is because when I lift the enlarger head higher to make, say an 11x14 or a cropped 8x10, the image goes out of focus... I'm turning the focus knob and it's hitting its limit, bringing the lensboard as close to the condenser head as it can go. So, I swapped the 50mm and the 75mm Beslar I have. Why, you ask? Because the 75mm was mounted in a lens board that had a bit of a counterbore in it, which would (apparently) put it another millimeter or two closer to where it needs to be for correct focusing. It was only a slight improvement, if any. So, my questions are: (1) Is this normal? (2) Do I need to start shopping for some sort of recessed lensboard for my new lens? (3) Why did I not have this problem with my Beslar lens if it was the same focal length?