Digital BW, The Print

Austin writes:

> My experience through literally thousands of hours
> of design and testing digital imaging systems is that
> all you do when you increase the exposure
> time is simply shift the data values, it does not
> increase the dynamic range unless the system has a
> limitation in the first place.

Logically, if the noise floor does not rise as quickly as the maximum signal
as exposure increases, then dynamic range will increase.  For example, with
zero noise, a longer exposure will always provide a larger dynamic range
than a shorter exposure (within the limits of the sensor).  If doubling the
exposure triples the noise, though, dyanmic range will be worse (not sure if
that can happen, though).