Dynamic range and RAW file "bit depth"

Started 11 months ago | Questions thread
szhorvat
Regular MemberPosts: 131
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Re: Dynamic range and RAW file "bit depth"
In reply to xpatUSA, 11 months ago

xpatUSA wrote:

In other words, if I present my sensor output with it's theoretical 16.23 EV range to an 8-bit ADC is the sensor dynamic range any different than if it is presented to a 14-bit ADC?

Disclaimer: I don't go to DXOMark very often. And I'm not sure that I've answered the question.

I'll say: For practical purposes, yes, the dynamic range will be smaller in that case, provided that the digitization is done in a linear way.  The smallest number of electrons we could measure (by looking at the digitized signal) will be 77000/2^8 = 300.  It won't be possible to see the difference between 200 or 400 electrons, as all will be rounded to the same 300.

Unless ... we take the "dithering" done by natural noise into account.  Which I didn't think of.

Or unless the digitization is done in a nonlinear way, i.e. out of the 2^8 = 256 values, 1 will correspond to something smaller than 300 to have a higher resolution in the dim range.  So another possibility is that the sensor itself it linear but the digitization is done in a non-linear way.

Or maybe there was something else I didn't think of.  Which is why I asked the question

Thanks for taking the time to reply.

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