Stephen Benskin
Member
Any system will work most of the time. Because 68% of outdoor scenes falls within a +/- 1 1/4 stop range from the average, it's hard for a system not to work most of the time. Think of disposable cameras. It's the extreme conditions that matter. And even so, 95% of scenes fall within +/- 2 1/2 stop range of the average, and graded paper can handle most of those situations.
The one thing about any system is that it tends to limited the choices by attempting to simplify the methodology. Why not use the best parts from the different systems depending on the situation? Pegging the key tone or exposure weighting based on a critical tone are valid approaches depending on the situation. Picker was fine pegging the highlight most of the time. He assumed the average luminance range would have the shadow fall around its proper place. This isn't much different than exposing for the middle, like off a gray card or incident meter. Both assume a relationship between the mid-exposure and the shadow exposure. Most of the time, it works. In truth, it's hard for an exposure to fail more than 20-25% of the time with outdoor scenes no matter what you do. That's why there are so many different exposure systems out there.
The one thing about any system is that it tends to limited the choices by attempting to simplify the methodology. Why not use the best parts from the different systems depending on the situation? Pegging the key tone or exposure weighting based on a critical tone are valid approaches depending on the situation. Picker was fine pegging the highlight most of the time. He assumed the average luminance range would have the shadow fall around its proper place. This isn't much different than exposing for the middle, like off a gray card or incident meter. Both assume a relationship between the mid-exposure and the shadow exposure. Most of the time, it works. In truth, it's hard for an exposure to fail more than 20-25% of the time with outdoor scenes no matter what you do. That's why there are so many different exposure systems out there.