Hopefully someone here can help me understand this better. A given camera will state that it has X amount of dynamic range. For example, my Canon 5D Mark III has 10 stops of dynamic range. An Arri Alexa has 14 stops of dynamic range. Film (e.g., Kodak Vision 3 500T) is said to have about 14 stops of dynamic range as well.
However, there’s no way I can actually capture anywhere near 14+ stops of dynamic range in any given image. Even HDR (stills or video) only gives me a few extra stops up or down (and if abused, saccharine images!). For my still photography, I mostly use the Zone system and spot metering, especially for a high contrast scene. For example, if I know that I want a window to not blow out (and to be able to see what’s there), I can’t go over 2-3 stops from 0EV/correct exposure if I want to recover any highlights, so I meter on a highlight, adjust shutter/ISO/f-stop to set it be two stops over, then shoot (assuming my subject isn’t too dark, obviously). On the other end, I know anything below 2-3 stops from EV0 will be crushed.
Referring back to the Zone system, after I determine Zone V (middle gray, 18%), I know that anything below Zone II will be crushed, and highlights above Zone’s VII or VIII will be blown out. So, the best I can tell, I can only get about 6-7 stops of actual dynamic range in an image; certainly not the 14+ stops talked about.
Also, I already know they measure the DR of a camera using a grayscale chart from black to white, with each lighter color representing a stop of exposure. That’s all well and good, but that doesn’t really carry over to the real world… does it?
So, what gives? What am I missing?