> On Dec 12, 2006, at 12:06 PM, Cory Papenfuss wrote:
>
>> I'm not saying I know how it's done... just trying to provide food
>> for thought. RAW isn't RAW anymore if the 22-bits have been
>> truncated on
>> a per-channel basis to 12...
>
> RAW format has always been what was written from the sensor into a
> digital representation, a 2D array of photosite values along with
> metadata describing the camera state and organization of that array,
> no matter what transformations or A-D conversion methodology has been.
>
Right. It isn't anymore unless the RAW file has 22-bits of data
per photosite.
If it's 22-bits truncated to the 12 most-significant bits,
there's no reason for 22-bits to begin with. One would expect that the
"most relevant" 12-bits of dynamic range would be chosen to truncate into
the 12 for a RAW file. The "most relevant" is the part that could be new.
With previous cameras with 12-bit A/D's, one could be reasonably
certain that ALL data captured was recorded in the file. That is no
longer the case.
-Cory
--
*************************************************************************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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