Quote Originally Posted by Terry Again View Post
But I think the SRT only has DIN and ASA no ISO and it seems a lot of films sold now only list the ISO how does one compare the different types of speed listings of films?
ISO is the amalgamation of the old American ASA and German DIN standards.

e.g. a film previously rated as 400 ASA and 27 DIN is now marked ISO 400/27 although often now, the old DIN figure is left out e.g ISO 400

Doubling the ASA increases the DIN by three.