Good Morning, Chuck,
I use a Beseler MCR-X with the condenser head. When positioned for 4 x 5 film (according to the scale), the bottom of the condenser lens is quite near the negative; in fact, I make sure that it is very clean, because a dust spot on the bottom of the condenser may sometimes come almost into focus on the print and be visible. I cheat a little by positioning the condensers slightly higher than the 4 x 5 mark on the scale, maybe one-eigth to one-quarter of an inch. I still get enough coverage in most cases. Just because of this potential problem, I generally compose a little "loose" so that I don't have to worry about the extreme corners on the negative.