Darktable: apply camera's filters, lens correction and crop by default in darkroom mode

Question

I have a Sony Alpha mirrorless camera. When I preview my photos from the lighttable, they look like they do on the camera. But when I open in darkroom, the aspect ratio, lens correction and color correction are wrong.

I'm assuming this is a feature, not a bug, but I'm not sure. I can manually set lens correction and crop the image to the correct aspect ratio, but I find it hard to get the color temperature the way I set it on the camera.

Really, I just want darktable to apply the settings from the camera automatically in darkroom mode. How do I do this?

Answer 1

First off, darktable doesn't know how your manufacturer processes it's jpegs, each camera is different and the method an important differentiator between camera's and manufacturers.

In the preferences is a section for GUI (graphical user interface) options, specifically:

Don't use embedded preview JPEG but half-size raw

Check this option to not use the embedded JPEG from the raw file but >process the raw data. This is slower. (default off).

Unless told otherwise darktable defaults to showing the small jpeg preview embedded in the RAW file by your camera which will have all the settings your camera had at the time applied to it. Once you have opened the image and edited it, the preview is updated to reflect your edits. This is most noticeable if you take an image with the camera's black and white settings on. The preview jpg is black and white but the RAW is a colour image. You're camera's own software (and any that pays for the info) will then apply the black and white settings itself. Darktable and other free open-source software doesn't have access to this information.

It is possible to use ctrl+c / ctrl+v to copy and paste full or partial history stacks from one thumbnail to another or create styles which are basically a recording of the history stack of modules that have been used on one image and saved under a preset name to use on another. See history stack and styles.

In Junkyardsparkle's answer here a third option is described where the darktable-chart binary is used to try and creating base settings to mimic the output of camera modes. The Darktable manual page 1.1.4. darktable-chart binary describes it as

"This binary is a dedicated utility to create styles out of pairs of images such as RAW+JPEG with in-camera processing."

Using darktable chart states:

10.3.1. Overview

With darktable-chart we provide a tool for extracting luminance and color values out of images taken from color reference cards like IT8.7/1 charts. Its main purpose is to compare a source image (typically a largely unprocessed raw image) to a target image (typically a JPEG image created in-camera) and produce a darktable style that is able to convert luminance and color values of the source image to produce the target image. This style employs the tone curve module, the input color profile, and the color look up table module for that purpose (see Section 3.4.2.3, “Tone curve”, Section 3.4.3.11, “Input color profile”, and Section 3.4.3.6, “Color look up table”).

Some cameras are particularly advanced in offering various film simulation modes of your choice. With the help of darktable-chart and the underlying modules you can now create styles that replicate these film simulations from within darktable.

Answer 2

Your previews are just that - previews. They're in-camera generated JPEG images created using the cameras current settings and raw conversion engine that are attached to the raw image files at the time the image is captured.

But Darktable (most likely) doesn't have access to the algorithms used by the camera's JPEG engine. Instead, it uses it's own engine and the default settings you've told it to use when initially opening an image, rather than the in-camera settings at the time the image was captured.

For more, please see:

Are paler raw images normal for a newer sensor with higher dynamic range?
Why is there a loss of quality from camera to computer screen
While shooting in RAW, do you have to post-process it to make the picture look good?
How to make camera LCD show true RAW data in JPG preview and histogram?
Why do RAW images look worse than JPEGs in editing programs?
Why do RAW images in Darktable have a lot of noise?