DNG from Huawei P20 Pro CLT-L29 shows f/0.0 0.0s iso0 0.00mm

[alexkiri]

• Version details Version: 5.8 Branch: releases Commit: 9a9e0acbf Commit date: 2020-02-04 Compiler: x86_64-w64-mingw32-gcc\ 8.2.0 Processor: generic x86 System: Windows Bit depth: 64 bits Gtkmm: V3.24.2 Lensfun: V0.3.2.0 Build type: Release Build flags: -mwin32\ -m64\ -mthreads\ -msse2\ -std=c++11\ -mtune=generic\ -Werror=unused-label\ -Werror=delete-incomplete\ -Wall\ -Wuninitialized\ -Wcast-qual\ -Wno-deprecated-declarations\ -Wno-unused-result\ -fopenmp\ -Werror=unknown-pragmas\ -Wno-aggressive-loop-optimizations\ -DNDEBUG\ -O3\ -ftree-vectorize Link flags: -m64\ -mthreads\ -static-libgcc\ -mtune=generic\ -s\ -O3 OpenMP support: ON MMAP support: ON

• Operating system Windows 10 Pro Version 2004 (OS Build 19041.658)

• Steps to reproduce Browse to the folder containing the file. Open the DNG file. The top left label shows incorrect parameters

• Raw file https://drive.google.com/file/d/1LfhReGqXwEKTrI7vui6BYIpMnij3MWrz/view?usp=sharing

• Screenshot

[kmilos]

I venture this is similar to what was happening in darktable: metadata was only searched for in the Exif IFD, but most smartphone DNGs don't have it (nor is Exif part of the DNG spec to begin with). Most (basic) metadata of the DNG is stored in the main IFD0 instead.

You can check this is indeed the case by e.g. running exiftool -a -u -s -g1 on this sample.

This was also partly addressed by the "easy access" API of exiv2, so that should also help once RT makes the switch.

[alexkiri]

FNumber                         : 1.8
ISO                             : 3200
DateTimeOriginal                : 2020:08:27 01:41:48
FocalLength                     : 5.6 mm

Yup, exiftool shows the correct info

[kmilos]

They key, however, is where that info is stored in the file: IFD0; there is (normally) no Exif IFD in DNGs (TIFF/EP).

The location you get with the -g1 (or -G1) options of exiftool, and you can also tell from the Exif.Image (IFD0) vs Exif.Photo (Exif IFD) prefix when you do exiv2 -pa:

Exif.Image.FNumber                           Rational    1  F1.8
Exif.Image.ISOSpeedRatings                   Short       1  3200
Exif.Image.DateTimeOriginal                  Ascii      20  2020:08:27 01:41:48
Exif.Image.FocalLength                       Rational    1  5.6 mm

[alexkiri]

Here is some extra relevant info

[IFD0]          FNumber                         : 1.8
[IFD0]          ISO                             : 3200
[IFD0]          DateTimeOriginal                : 2020:08:27 01:41:48
[IFD0]          FocalLength                     : 5.6 mm
[IFD0]          TIFF-EPStandardID               : 1 0 0 0
[IFD0]          DNGVersion                      : 1.4.0.0
[Composite]     Aperture                        : 1.8
[Composite]     ShutterSpeed                    : 30
[Composite]     FocalLength35efl                : 5.6 mm

[Lawrence37]

The link to the raw file does not work anymore. Do you have a sample file to share?

[FloBEAUG]

The link to the raw file does not work anymore. Do you have a sample file to share?

Sorry, the problem isn't on dev branch anymore. Thx

[alexkiri]

Sorry, I removed the file from drive, I forgot about this issue. I just tested with a new raw file from the same phone, and it appears to work correctly with the latest stable version 5.11. Many thanks! This issue can be closed