He's not asking about whether he can use old manual lenses. He's talking about the split screen in the view finder in old SLRs that helped you (immensely!) when you had to manual focus.
With the split screen, any object in the screen will be split in two and will be out of alignment unless they are in focus. This allowed you to consistently and quickly achieve really sharp focus manually. With current DSLRs, without a split screen, manual focusing is really difficult by comparison.
With an old manual Yashica, I remember being able to focus as fast as my current DSLR in good light while being a lot faster in low light where my current DSLR might go focus hunting.
edit: And Djayvo, have a look at http://www.katzeyeoptics.com/cat--Penta ... entax.html
for customized focus screens. While they're quite cheap (and available for Pentax but not Sony
), I imagine they're going to be a pain to install.