Welly, unless you are planning to place your shadows on zone V, the easiest method is to meter your shadows and highlights before placing your shadows. That makes it easier to determine the spread. So, for f16 you meter your shadows at 2s and highlights at 1/250. Now you know your spread (9 stops). Then simply place your shadows and count nine zones up from there to determine where your highlights will fall with normal development. In your case, zone III for shadows puts your highlights on zone XII.
I am very often working with very long luminance ranges when I photograph. And I would warn, as I have done in many other threads, against using the zone system too "rigidly" under these circumstances. Assuming the highlights you metered are not specular and you want to render them with detail, the zone system math says N-4 development.
I caution people to do a more thorough evaluation of the scene, and how they want the final print to look before making that decision. I'm refering to wet printing here, but the principles still apply. Simply developing to bring bright highlights down to zone VIII does not necessarily mean they will have detail in the print. It means only that the scale of the negative will fit onto the paper without manipulation. That is not the same thing at all. Zone VIII on the paper will only have detail if it is in the negative.
Where long luminance ranges are involved, the relationship between what is in the negative and the scale of the paper is fundemantally misunderstood by many zone system users.
Last edited by Michael R 1974; 03-08-2012 at 08:54 AM. Click to view previous post history.