>>>> Typically, the image data only falls in part of the range of the CCD,
>>>> and should be more in the middle, not the ends.
>>> Well, that's part of my point.
>>You're suggesting treating the CCD non-linearly it appears.
>No. I'm saying that the signal to noise ratio changes depending on the
>input voltage.
I understand that, and I believe if you think it through, you need to treat
this nonlinearly in order for it to be meaningful. You are suggesting that
the actual dynamic range of the sensor is non-linear, that it is less at the
ends of the scale, and higher in the middle. You get less 'usable' bits on
the ends.
>> There is a thought to that, but I will say, that you're
>> probably not going to get any better (read as more usable)
>> information from it...would be my first thought.
>In my experience there if far less noise in mid tones than dark tones of
>a slide.
No doubt, but that doesn't necessarily translate into more usable
information, if the system already is designed to take advantage of it.
>> I believe that doing either multiple exposures and/or
>> multiple input ranges pretty much does the same thing,
>> doesn't it?
> That's something else.
But gives the same results. I believe your idea is really limited by the
'resolution' of the CCD, ie, its ability to discriminate...where noise will
eventually overcome any advantage additional bits will give you. I would
hope that the number of bits from the A/D 'system' is already matched to the
CCD in such a way that 'more' bits wouldn't give you any more usable
information.
