ExifTool Forum

General => Metadata => Topic started by: Klaus_Homeister on July 22, 2018, 12:37:58 PM

Title: Panasonic Makernotes 0x00A7
Post by: Klaus_Homeister on July 22, 2018, 12:37:58 PM
Hi Phil,
This one is only used by some old compacts like ZS40&50/TZ70/FZ70/LF1

It's a table of 2 colums with 432 Rows of unsigned shorts.

You get it with:

SUM1=0; SUM2=0;
for(c=0;c<Len/2;c++){
SUM1+=fgetc();
SUM2+=fgetc();


first Colum is integer in 16Bit depth;
second is integer in 14Bit depth;

Both end up at around 85% of maximum possible value of bitdepth.

When
you (1)develop 12Bit RAWdata.
And (2)upscale it to 14Bit.
You can use This table to map 85% of the dynamic range of 14Bit developed Data to 85% of a 16Bit image WITH Camera Contrast.

All values higher than the 14Bit-Limit of the table get unmapped(-14Bit TableLimit) put on the 16Bit Limit of the table ...
And highlights are compressed this way.
Result is an good 16Bit Tiff for output.

Bad news: this good tag is obsolete for all newer cams => all zero there.
-Klaus


Added a Histogramm

Title: Re: Panasonic Makernotes 0x00A7
Post by: Phil Harvey on July 25, 2018, 11:06:22 AM
Thanks!  Any suggestion as to what this tag should be named?

- Phil
Title: Re: Panasonic Makernotes 0x00A7
Post by: Klaus_Homeister on July 26, 2018, 10:15:10 AM
Hmmh,

it's a look-up-table.
And it applies cameras contrast and scales image-data for output.
I think camera uses it for jpeg-processing dividing the higher values by 65535.0f to get a range of 0.0-1.0 mapping to a 8Bit jpeg.

It's sure for postprocess ... applied to RAW-Data interpolating gets poor.
I would call it OutputLUT or PostProcessLUT.
Something like that.

-Klaus

Title: Re: Panasonic Makernotes 0x00A7
Post by: Phil Harvey on July 26, 2018, 10:23:10 AM
Hi Klaus,

Thanks.  I'll call it OutputLUT.

- Phil