« on: September 20, 2012, 02:53:49 AM »
2. They get more than 14EV on the normalized comparison, it's normalized to 8MP so with 36MP to play with there is a lot of room to get the extra bits after normalization there.
Exactly. Say you have 14EV DR at the pixel level; i.e. you've perfectly matched your ADC to the DR attainable at the pixel level (e.g. saturation capacity = 16,384 e- & read noise = 1 e-). But say this is for a 100MP sensor.
When you go to make a 4" x 6" print of that 100MP file, you'll be doing a lot of downsizing for a 300dpi printer. That process of downsizing will reduce noise. Therefore you will be able to lift shadows more while still producing an acceptable print. Therefore shadows with a pretty low SNR may suddenly become 'acceptable' the viewer of the 4x6 print.
Yada yada... that's how you get more dynamic range via normalization.
Although I still have a hard time wrapping my head around it.
Because if your SNR is ever <1, you're not going to magically recover the signal by resampling... resampling would only bring you closer to the average of the noise as SNR approaches 0.
But for more reasonable definitions of DR (e.g. Bill Claff's 'PDR' that defines the lowest acceptable SNR as 20), normalization expanding DR makes perfect sense.