darktable-org / darktable-org/darktable
Apply lens corrections using embedded metadata on converted DNGs (only tested on Sony ARW)
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- Dominant language
- C
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Description
Lens corrections using embedded metadata work fine on Sony ARW raw files, but not if the ARW is converted to DNG. Some CA seems to be corrected, but not distortion or vignetting.
According to ExifTool, the distortion, vignetting and CA correction parameters are copied over and present in the MakerNotes. Exif data has "WarpRectinear" listed for OpcodeList3 in the DNG.
According to the Lens Correction module, it says "Corrections done: Distortion and TCA" although it seems only TCA is being done.
So, not sure if it's a bug that distortion isn't being fixed, but if not, can it be enabled?
Two previous issues related to this request but were closed after sitting stale:
#15574
#15647
Sample files: https://www.dropbox.com/scl/fi/u7f74m7zqnk3mx8rae4eg/DNG-test.zip?rlkey=mprhnim54x3mgeewarwqvkm7a&st=t6ee8m23&dl=0
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the behavior with the linked DNG sample files and compare the converted DNG with the Sony ARW in the Lens Correction module. Use ExifTool to verify the copied distortion, vignetting, and CA parameters, and compare the module's reported corrections. Done means the DNG applies the expected corrections or the remaining limitation is clearly documented.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- computer-graphics
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100