lens correction preset with dynamic focal length


I’d like to have lens-correction enabled for all my pictures by default when I import them in darktable.

For this, I created a preset and set “auto apply this preset when criteria is matched”. for the criteria i choose the specific vendor/lens, where I know the lens-correction exists and works fine.

This works fine, and for every picture (if it is a zoom lens) the correct focal length is set accordingly.

The problem arises, when I want to change the preset in some way. For example - for certain lenses I do not want all corrections enabled, but only distortion and TCA (so no vignetting). As soon as I change this parameter, and then update the preset, it seems that also the focal length setting is hard-locked (although I didn’t even touch it). The next-time, the preset is auto-applied, it also applies the hard-locked focal-length. Which is very likely wrong if the lens is a zoom lens! In this case, the distortion is applied in the wrong way, and pictures even look more distorted.

How is it possible to change a parameter in the lens-correct-preset, without hard-locking the focal length also?

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You need to open a feature request at https://github.com/darktable-org/darktable/issues/new?assignees=&labels=&template=feature_request.md&title=
Saving a preset stores the current values for all parameters

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So it’s not possible. OK. Thanks for clarification.

Interestingly, it does not store all current values, if I don’t touch any of the parameters. So if I save the preset in the first place, coming from some random picture where the focal length is set to some random value. In this case, if I save a preset, this random value is not saved in the preset.

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There is already a bug report open at github:

I also suffer from the problem of darktable not correctly autodetecting my lens and thus relying on something like dynamic presets.