ExifTool Forum

ExifTool => Bug Reports / Feature Requests => Topic started by: nickspiker on September 14, 2022, 12:07:34 PM

Title: Black level tag returns incorrect values
Post by: nickspiker on September 14, 2022, 12:07:34 PM
Could be missing something but I'm pretty sure this is a bug.
I'm running Ubuntu and version 12.40 of exiftool
Here's what I get from running exiftool Caseandtarget.dng
Black Level : 40 20 0
but the actual blackpoint is 4,097
and here's a link (https://mega.nz/file/Ho5BhBAR#-JjM557JtMnw6-nZ7_JQIeMAR-lngndofGhnLlps7tg) to the .dng
Title: Re: Black level tag returns incorrect values
Post by: Phil Harvey on September 14, 2022, 12:36:21 PM
> exiftool Caseandtarget.dng -subfiletype -blacklevel -G1 -a
[IFD0]          Subfile Type                    : Reduced-resolution image
[SubIFD]        Subfile Type                    : Full-resolution image
[SubIFD1]       Subfile Type                    : Reduced-resolution image
[SubIFD2]       Subfile Type                    : Reduced-resolution image
[SubIFD3]       Subfile Type                    : Reduced-resolution image
[SubIFD]        Black Level                     : 4097 4097 4097
[SubIFD3]       Black Level                     : 40 20 0

There are multiple BlackLevel tags in this file.  I think you are interested in SubIFD:BlackLevel.

- Phil
Title: Re: Black level tag returns incorrect values
Post by: wywh on September 14, 2022, 12:40:09 PM
Use -a to show duplicate tags:

exiftool -a -G1 -s Caseandtarget.dng
[...]
[SubIFD]        BlackLevel                      : 4097 4097 4097
[...]
[SubIFD3]       BlackLevel                      : 40 20 0
[...]

- Matti
Title: Re: Black level tag returns incorrect values
Post by: nickspiker on September 14, 2022, 04:22:13 PM
Quote from: Phil Harvey on September 14, 2022, 12:36:21 PM> exiftool Caseandtarget.dng -subfiletype -blacklevel -G1 -a
[IFD0]          Subfile Type                    : Reduced-resolution image
[SubIFD]        Subfile Type                    : Full-resolution image
[SubIFD1]       Subfile Type                    : Reduced-resolution image
[SubIFD2]       Subfile Type                    : Reduced-resolution image
[SubIFD3]       Subfile Type                    : Reduced-resolution image
[SubIFD]        Black Level                     : 4097 4097 4097
[SubIFD3]       Black Level                     : 40 20 0

There are multiple BlackLevel tags in this file.  I think you are interested in SubIFD:BlackLevel.

- Phil

Awesome!
Totally makes sense.  Not sure why that didn't occur to me.