3.2ISO, EI, ASA, and YOU

ISO is one of those terms that we all take a little for granted. Once you get the general gist of ISO, it seems simple. So simple, in fact, that when I thought of this column on ISO, I first thought that it would be too simple and nothing to really talk about—until I started to try and put it all into words—and realized that ISO is a deceptively complex subject.


A digital light meter showing ISO and stop reading.

ISO is an acronym for International Organization for Standardization, the standards body who defines the particular parameters by which sensitivity of film emulsion was measured (among many other standards). ...

Get Behind the Lens now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.