PanasonicRaw CameraIFD various Tags

[Klaus_Homeister]

Hi Phil,

ok once more PanasonicRaw CameraIFD.

1st have a look to Tag 0x320A

This is always 16383.
Like 4095 in Tifftags defines the maximum value of 12Bit RAW-Data, here this could stand for 14Bit RAW-Data.

But RW2-Cams have all 12bps. This value stands for 14bps.
Hmhh ... this is a four times higher value than the real bitdepth.

Then have a look at Tag 0x140B a single value around 512 ...
and Then Tag 0x2009 ... as 2 Sets of 4 Values around 512

Hmmh ... this is four times higher than the Blacklevels from Tags 0x001C & 1D &1E  of PanasonicRaw

I Think that all those Tags from this IFD are related to a newer in-Camera development-process, where RAW data gets scaled to a higher bitdepth within the new colorbalance- and gamma-process.

0x320A is the resulting scaled Bitdepth. 14bps 16383
0x140B is the resulting scaled OverallBlacklevel ~512
0x2009 is the resulting scaled 4channelBlacklevel in two sets. {512+a,512+b,512+c,512+d}
(lowest of all 4 channels is OverallBlack above)
0x1411 is the difference of each channels black to OverallBlacklevel   {a,b,c,d}
This relations you can check with all RW/2-File of all Cams having this IFD.
...
and the Tag 0x3209 is the gamma-value for this process. always 512 Div 256.0f => Gamma 2.0

This seems to be valid for all cams up to GX9 ... except the video-Cams GH5 & GH5s and the G9.

But I have updated my experimental RAW-converter to this workflow ... and it works fine for all cams including GH5 and G9.
My loadraw-routine doesn't work for GH5s with new compression ... so this cam I can not check.
It's not perfect but one big step further.

Before this I did it like dcraw ... colorbalance and keep it linear .. interpolate ... and so on.

Now this way ... balance & gammacorrect RAW-data upscaled to 14bit ... interpolate ... and so on ... gives much more details and very low noise.

So I'm very sure to be correct for the meaning of all Tags above.


Greetings from Germany
-Klaus

[Phil Harvey]

Great, thanks!

I'll add these when I get a chance, and post back here if I have any questions.

- Phil