I tested HC 80mm on H2, the autofocus is very accurate with the spot meter. I can focus right at the eye ball within 0.1mm accuracy,..., in a distance of 3 meters.
However, it's very annoying that the H2/DB combination keeps on complaining "restart back error". I have to take off the back from the body then reattach to get ride of the problem, otherwise it won't reboot once it's power down. I was told this is not a problem particular to that set, it's a common problem. Sounds like a bug. Once the problem shows up, restartig the back will also turn on the cooling fan. ..., sounds like a semiconductor latch-up or something. Very scary.