reversal film and spot meters

Daniel Madsen · March 7, 2007

Spot meters it seems provide the clearest results when using negative film. There are ten zones and more or less 10 stops of latitude with negative film, so a spot meter is giving you the f-stop necessary to render your ?target? grey, zone five. What about w/ reversal with a much higher contrast and latitude? Can you rely on your meter to give you a zone 3, 4 or even an image?

Michael Nash · March 7, 2007

The correlation between spot meter readings and "zones" reproduced on a print or telecine transfer is highly variable. Not all negative stocks have the same characteristic curve, nor do all print stocks. You really have to test the stock and finish format together to be sure what you're getting.

It is true though that reversal films have a much steeper characteristic curve than negative films. It's been a long time since I shot reversal but I wouldn't expect much more than two stops of over- or under-exposure before you would lose detail in midtones. But again, you'd have to test the stock and finish format to be sure.

In practice it is a good idea to know the limits of the stock you're using, as well as the shoulder and toe characteristics of that stock. Since many films "roll off" highlights and shadows differently, it's helpful to know how the film will respond to detail that's close to the limit, but not completely lost.