Quote Originally Posted by TimFox View Post
I have no idea how the digital camera manufacturers define the "ISO" value on their cameras, but I suspect it is closer to "EI". If you change the "ISO" setting on a film camera, it only effects the setting on the internal light meter (with or without auto exposure based on that meter).
They do the same as Ilford: they evaluate "ISO" on a practical, rather than ISO standard form. Most (all?) Ilford films have disclaimer like this:
"It should be noted that the exposure index (EI) range recommended for 100 DELTA Professional is based on a practical evaluation of film speed and is not based on foot speed, as is the ISO standard."

Edit: actually I was wrong, there is ISO for digicams: http://www.dpreview.com/forums/thread/2838786

I wonder how accurate my digital metering for film is then... :-/