The Zone System and the Leaf Aptus-II 5
The Leaf Aptus-II 5, ISO 25, 16-bit RAW capture (14 effective), Adobe Camera Raw controls zeroed:
Zooming in on the shadows:
At the shadow threshold (L* = 2, about zone -1/2), the SNR is about 5. Let us see how far down we can go and retain good shadow quality. Setting Exposure to +1 (N+1):
The threshold SNR at N+1 is a little low, below our desired minimum of 4. How about N+0.5?
N+0.5 looks good just above zone -I. What about raising the Blacks level to improve shadow contrast as we did before?
Let us pick Blacks = 2:
Now for the highlights:
So the Leafís highlights run higher than the Nikonís at the start, but are not as recoverable as the Nikonís with reduced Exposure.
Here are four zone rulers, made at N+0.5 (Shadows at 0 and 2), N, and N-1. Good-quality print detail extends from just above zone -I to VIII 1/2, for a dynamic range of over 9 stops:
The Nikon texture target images were very close to the same values as the gray card images; for the Leaf they were 1/3-1/2 stop darker:
|N, zone O||N+1, zone -I||N+2, zone -II|
|L* = 2.0
SNR = 5.1
|L* = 1.9
SNR = 3.3
|L* = 2.0
SNR = 2.1
|N, zone VIII||N-1, zone VIII 1/2|
Next: an example