willie_901
Veteran
I agree - I'd have thought they would be required to operate to the Standard, in order to use the ISO rating.
However, if you looked at the sites I mentioned, you will have seen that there are plenty of people discussing the possibility that this is not the case. IDK.😕
Well, FUJIFILM is a member of a Japanese organization CIPA, Camera & Imaging Products Association. These CIPA guidelines recommends CIPA members measure/calibrate sensitivity using either the Standard Output Sensitivity (SOS) or Recommended Exposure Index (REI) methods.
The International Standards Organization publishes more than one standard for camera sensitivity (ISO).
CIPA members are not obligated to follow any of the International Standards Organization protocols.
However the issue of what standard applies can not explain the two stop problem you report. The reports of sensitivity discrepancies you mention are a diversion from the strange behavior you'r experiencing.