Okay- so we used to have this system. ASA film numbers. Typically, 100 (normal speed), 400, etc. etc... and we had a european system called ISO - where 100 ASA translated to 21 degrees ISO. Every doubling or halving of ASA speed would result in adding 3 or subtracting 3 to the ISO scale. Logarithmic scale. Simple enough. But in recent years, everyone's referring to what was PREVIOUSLY ASA as ISO. What gives? Sorry if I'm not on the bandwagon - guess I stopped paying attention years ago.

Can someone also give me the lowdown on granularity indices? According to what I've read/heard, Fuji NPS should be a much finer, more detailed film than Velvia 50 - which makes no sense to me.

Thanks so much, if anyone has any feedback opinions on these issues...!