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-   -   Distortion when importing raw images caused by Linux OS? (https://www.linuxquestions.org/questions/linux-software-2/distortion-when-importing-raw-images-caused-by-linux-os-4175609825/)

nccm 07-14-2017 01:23 AM

Distortion when importing raw images caused by Linux OS?
 
I am working with Kubuntu 16.04.

When I import raw photos in any available raw editor (rawtherapee, ufraw, lightzone, ...) there is always a strong barrel distortion. I have tried completely reinstalling the programs, including deleting the configuration files in the home directory, but without effect.

The thumbnail images (from the included jpeg file) do not show the distortion.

When checking at a friend's computer LightRoom (Windows) there is no distortion. It is definitely not in the original raw file.

Since all raw editors show the same distortion I think that the Linux OS does "something" with the raw file when it imports it in the raw editor.

Is there a solution? I am almost desperate!

Niels

pan64 07-14-2017 02:20 AM

I think that is impossible. I don't know what did you exactly try, but linux itself does not care about your images and will not correct any kind of distortion "automagically".
From the other hand I have no idea if that distortion is really there (because of the lens you use), or it is just some kind of effect applied by any kind of software.
The thumbnails are probably too smalls to check the images (and do not forget, they are already processed somehow).

nccm 07-14-2017 02:49 AM

Thank you for your response.
Of course I completely agree with you.
But it is a fact that all raw editors in Linux show the same distortion.
So I think that it hard to believe that it depends on the editor.
In gwenview the distortion is absent, but I guess that here the jpeg is shown.
I will wait for possible other replies and see if someone has the same problem (solved).

TenTenths 07-14-2017 04:29 AM

Hi!

You make a few wrong assumptions and conclusions in your original post.

Quote:

Originally Posted by nccm (Post 5734705)
When checking at a friend's computer LightRoom (Windows) there is no distortion. It is definitely not in the original raw file.

The distortion IS in the original RAW file. A RAW file contains pretty much the raw data captured by the sensor.

It also (importantly) can include any image correction data that the camera has written in to the RAW file based on the information the camera has about the lens.

Some RAW image processors can deal with this data within the RAW file, some make use of "external" databases of correction data.

Lightroom, being from "the daddy" of image processing, Adobe, copes well with this.

You may find the following articles of interest:

https://helpx.adobe.com/camera-raw/k...ed-lenses.html

https://helpx.adobe.com/x-productkb/...e-support.html

Quote:

Originally Posted by nccm (Post 5734705)
Since all raw editors show the same distortion I think that the Linux OS does "something" with the raw file when it imports it in the raw editor.

Yeah, it's not applying the correction data or doesn't have knowledge of the particular lens.

Quote:

Originally Posted by nccm (Post 5734705)
The thumbnail images (from the included jpeg file) do not show the distortion.

The thumbnail is a processed image created by the camera using the correction data.

Not sure what the actual solution to your problem is but just thought you might like some clarification on what's actually happening with your images.


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