I'm still getting used it. With the Fujinon lens it's easy because you can press the AE-L/AF-L button and it will focus if your far away from being in focus. With the Pentax and Chinon lenses its difficult. I want to use the Chinon for street photography until I either get a Leica 35mm f2 Summicron or the Fuji 35mm F1.4 R lens. From what I've read if I find a sweet spot of focal length and aperture depending on lighting conditions and switch to Auto ISO with a cap of 3200 this will allow quick snaps with a majority in focus, or thats the theory.
Two more with the new lenses, the bottom is the Pentax fully stopped down, the top is the Chinon. They are soft but have a creamy lush look.
The Billingham is a superb bit of kit and I'm glad I chose it over another Lowepro.