> I didn't say no processing was done. You did. It was stated in one of
> the interviews with the engineers that Ken translated that they took
> opportunities to do signal processing due to the 22bit A-D that were
> not otherwise feasible.
>
... *before*. The common thought previously was that RAW provided
unaltered A/D data of the sensor. That may or may not have been true, but
at least it *could* have been. Now with truncation necessary, it *cannot*
be true that a RAW file contains unaltered digitzed sensor data.
>> Yes, but no longer presumed to be an unaltered digitized version
>> of exactly what the sensor sees.
>
> It never has been. Transformations occur between photosite and
> digital representation in all cases that I'm aware of ... that's what
> all the custom signal processing chips in these cameras are all
> about, in part at least.
I'm curious as to what these transformations are. The only
ones I can think of off the top of my head are dark-frame subtraction
noise reduction and possibly hot/dead pixel removal.
>> For the most part, this is speculation since nobody but the
>> image-processing software guys at Pentax know for sure. I'm just
>> saying
>> that not only is what I'm suggesting possible, it's rather *likely*
>> given
>> that they're trying to exploit the additional data available.
>
>
> But as I said above, the whole concern is nonsensical and pure
> speculation because you only get the RAW data the camera writes
> anyway. And the little working with the K10D that I have done so far
> indicates pretty clearly that it has exceptionally good image
> quality, even compared with the *ist DS which also has very very good
> image quality. The K10D has "better" 12 bit RAW data, in other words.
> I think that it is in part due to the 22bit A-D and whatever data
> massaging they do in that space, at least in part.
>
That's the point though... even as it is, there are some
user-adjustments that likely may affect the RAW file. Setting a different
colorspace (sRGB vs. AdobeRGB), or setting a different white-balance will
affect the conversion of 22-bit RAW to 12-bit RAW. That flies in the face
of the idea that one can, "shoot in RAW and not worry about WB and other
color settings."
> If you want to continue to speculate for no particular reason, well,
> be my guest.
>
It's not pure speculation. When I first got my -DS, I dove into
the color management and white balance stuff. One of the things I did was
add a white-balance (warming) filter on the lens and shoot a very cool
color temp shot (overcast, evening approaching, etc). Bottom line was
that after adjusting the WB in the RAW conversion between the filtered and
unfiltered version, there was less noise in the channels that were
captured approximating 5500K color temp.
Bottom line: It was better to filter out (via the lens filter)
the light that would blow out a single channel (like blue on an overcast
day or red for a sunset) and then increase the exposure to bring *all* the
levels up. Quantifiably less noise in the lower-level channels by doing
that.
Sometimes being an engineer is a curse... :)
-Cory
--
*************************************************************************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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