wrote:

Timo Autiokari wrote:
Exposure adjustment in fact is a linear
operation, multiplication by a factor,

Incorrect. It's scaled in F-stops, which are exponential, not linear.

Exposure adjustment by +1 fstop is the same as multiplication of the
data values by 2. Exposure adjustment by +2 fstop is the same as
multiplication of the data values by 4. So a linear operation. Just
the gradation of the aperture and the time dial is logarithmic, they
both affect to the data linearly.

You'll find the mathematical details in
any good textbook onphotography.

Then study them.

Timo Autiokari