[filmscanners] RE: Density vs Dynamic range

["Austin Franklin" <darkroom@ix.netcom.com>]

JULIAN....oh, JULIAN... (R that is...)

> The term "dynamic range" is simply defined for ANY system as the ratio of
> the largest possible signal to the smallest possible signal which can be
> handled without changing system parameters (usually smallest is determined
> by "noise" or some equivalent).

Above, you CLEARLY say dynamic range is based on noise...but here:

>Julian:  This example system for some reason has a noise of 1V, a smallest
>discernable signal of 2V and a largest signal of 10V.

> I'll do it here:
> DR = largest signal/smallest discernable signal
>          = 10/2
>          = 5
>
> That is, the dynamic range of our example system is 5.

> 7) If you agree they are different, then this explains why you say the
> example dynamic range is 8 and the definition that is used by everybody
> else uses gives a dynamic range of 5.

OK, your point 7) here makes me believe YOU believe the DR of the above
example is 5, YET YOUR use of the terms for that equation clearly shows that
equation is NOT based on "noise", but on the smallest signal LEVEL, and in
the example you CLEARLY show that noise is different than smallest signal
level (which you are mistakenly calling "smallest discernable signal", which
is not the correct term).

OK, so why do you now say that DR IS based on noise, and prior to that, you
give an equation, which it appears you believe has arrived at the correct
DR, that is NOT based on noise, but the smallest signal level?

Austin

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