Mark, that is why I suggest using the ISO speed as a starting point to determine the photographer's personal EI. Most pop testing methods have too many questionable elements that any true accuracy is impossible. All that they can really offer is a way to determine a personal EI. This is what most photographers really need, which is fine if they understand this. What I find troubling is when photographers question the legitimacy of the ISO standards based only on an understanding of a questionable "pop" methodology.
Originally Posted by markbarendt
Since obtaining a personal EI is the goal for most photographers, why then waste the time with a convoluted testing method. Shoot some negative as determine how you tend to exposure. But first, determine your processing.