Each DNG raw image from my Leica Q2 Monochrom that I open in darktable shows vignetting in the corners until I go to the lens correction module and change the correction method from “embedded metadata” to “lensfun database”. How can I make this selection the default for images from the Q2 Monochrom so that I don’t have to manually make the change for each image?
This is with Darktable 5.6.0. I tested on both Linux and Windows, the the behaviour is the same on both platforms.
It would involve creating a preset, and specifying to auto-apply this module+preset to all or certain images.
I have not done this for lens correction, a specific camera, or a specific lens, so I’m unable to be more exact. But this is, I’m sure, where you need to be!
Once you choose “lensfun database”, you can store that setting as a new preset.
You give it a name (e.g. Leica Q2 M) and in the dialog you enter the model of the camera or the lens for which you want to be automatically applied.
You might need to set a hotkey that changes the correction method. I’m wondering if a preset, even for something this specific, might not work correctly for all images. (I think the aperture and focal length settings might be forced to ‘wrong’ values on different images)
I have photos take with different Nikon Z lenses and the correct lens is recognized each time from the metadata and correction applied with the corresponding 𝑓 number and focal length.
Thanks. I was able to make a preset to force use of the lensfun database for all images from camera model Q2 Monochrom.
I wonder if creating a style that includes some basic editing steps such as denoising, sharpening and lens correction would work for you.
Or several. I use styles more for defining workflow than for defining looks.
Thank you for this thread! I never realised that I needed to make this change for one of my lenses. Using lens fun, rather than embedded data, makes a substantial difference to those images.
Now I have to automate that 
I had the same problem when darktable switched to embedded metadata by default, as the data in the Tamron 17-70/2.8 for Fuji is wrong at certain focal lengths (e.g. 20mm). I gave up on playing with preset, and patch the source code everytime I pull/recompile darktable instead 
, e.g.: patch -p 1 < default_lensfun.patch
default_lensfun.patch (672 Bytes)
Thanks! It’s certainly a never-say-never, but I am not comfortable with patching code, and wouldn’t do so unless it was something important to me.
Out of the two lenses I use on most outings, it affects only one, and that one will be less than five out of 50-100 shots. It is easier for me to manually change.
Oh… I probably have to resave the style with the new auto-apply preset. At some time, I’ll sort it. On the to-do list.