Quote Originally Posted by Stephen Benskin View Post
This is about the relationship between the subject luminance range, camera exposure, and sensitometric exposure. I'm working on something that will support my answer to your question. The range above the metered exposure point is approximately 0.92 logs and the range below is 1.28 logs (not including flare).

It works something like in this example. The ranges have been rounded to simplify the example. Note where Hm falls compared to the shadow exposure and remember this is the exposure for a 125 speed film - Hm = 0.0064 lxs Hg = 0.064 lxs.

Attachment 68594

For reference, here are the sensitometric exposures for a 0.00 to 3.0 density step tablet exposed at 2.048 lxs.

Attachment 68595
I see the bottom is practically zero. So adding "about a stop" for flare would bring the bottom of the "standard subject range" about to 0.10 density. Not that the low end of the range "hits" the speed point, but that flare effectively makes your film have the density associated to the speed point.