You are correct, of course. But this "dynamic range capability"
of JUST the file ONLY tells you how many subdivisions you can make
from a given input source.
Let's use a ladder analogy. The dynamic range of the input is how
high it is from ground level to the roof of the building I want to
get to.
The dynamic range of the ladder (as you define it) is simply the
number of steps I am allowed to have on the ladder.
No matter HOW HIGH the building, a 10-step ladder can be made to
reach the top of the building. However, those steps may be too
large to be of any practical use for a human to use that ladder
effectively.
If I want the steps to be 1 foot apart, though, THEN a larger
dynamic range ladder (more steps) is required to reach a larger
dynamic range (more height) building.
But without the restriction of "steps must be closer than 1 foot
from each other", the dynamic range of the ladder (number of steps)
says nothing about the dynamic range of the building (height) that
I can build a ladder to reach.
This has NOTHING to do with what we're talking about. Mapping of
bits to arbitrary EV values (compression, expansion, gamma,
contrast) does NOTHING to change the dynamic range capability of
THAT FILE. Once again, the scene or music, or the input source
has nothing to do with the dynamic range capability of a certain
number of bits, eg. a file format.
--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise