Right, I'm properly confused now
I'm on the H4D-40 (1.3x crop factor), and here's what I thought I understood up until now:
Using the CaptureOne focal length calculator, and inputing into the P30 column since the P30 is a 1.3x crop and same size, i.e. 44x33, as the H4D-40 sensor:
28/4 HCD on H4D-40/31 = 22mm on Nikon D3
35/3.5 HC on H4D-40/31 = 28mm on Nikon D3
50/3.5 HC on H4D-40/31 = 39mm on Nikon D3
80/2.8 HC on H4D-40/31 = 63mm on Nikon D3
100/2.2 HC on H4D-40/31 = 78mm on Nikon D3
120mm HC Macro on H4D-40/31 = 94mm on Nikon D3
150mm HC on H4D-40/31 = 118mm on Nikon D3
210mm HC on H4D-40/31 = 165mm on Nikon D3
is this about right?