I shoot Fuji Pro 400H in old folding cameras with a limited range of shutter speeds and aperture settings, and those are not always reliable. It has proved to have considerable latitude to under/over exposure. My use of Portra 400 is less, but that too has shown minimal colour shifts under similar conditions. Talk of 5 to 7 stops latitude may be overstating things, but both are as good as medium-fast film ever achieved in that respect. Personally, I shoot them at box speed as a starting point.

This might help:
http://www.twinlenslife.com/2010/12/...light-new.html