Originally posted by audiobomber ...
The Dynamic Range spec does not measure noise. DR is the amount of signal captured, measured in EV stops between the brightest recorded portion of the signal and the darkest.
I showed that number of over 3 stops really exists. 3.5 EV is the difference in dynamic range between the two, so it is 3.5 stops.
Regarding noise, it does relate to dynamic range. If you work on an image that is captured using lower DR (say K7), and want to process it so it appears it has more substantial darks, highlights, mid-tones, etc — more substantial tonal stretch, or give it an appearance of an image of a higher DR (k5), you interpolate 'noise', or controllably random information into it, like grain.
How much noise you want in it, depends on the DR you wish to achieve.
So loosely saying, the difference between the K5's DR and K7's DR is also 3.5 light stops of tonal stretch generated by noise, or random grain, required to make K7's image achieve visually similar appearance to K5's.