About two years ago I asked this same question about including a manual control for barrel or pincushion distortion in darktable. But I failed to get enough interest from a capable person to develop this feature for darktable.
One developer suggested the Rawtherapee fix might be adaptable to DT. I am not sure if this new post might prod someone to consider a solution to this issue. In the meantime I will just work on this problem using GIMP which has a lens distortion filter.
I do appreciate that the developers volunteer their time and DT users can’t expect everything they want to be made available in the program. So if no developer is interested in solving this problem it is not a problem to me. Thanks.
Just sometimes, but it would be helpful not to have to depend on a second program for a basic correction. I also find in the lens correction module I sometimes have to manually override the vignetting but that option is available. It would also be good if distortion can be overridden in the same way.
I find the use of the word “shame” for a feature you want not being in the software a bit manipulative and offensive. It sounds like the developers are doing something wrong for not working on your priority.
I was not trying to manipulate or offend. I have already acknowledged that the developers are volunteers and “DT users can’t expect everything they want to be made available in the program”. I just mention the idea in case one of the developers might be interested in this feature. There are a number of new developers and maybe one of them might be interested, but if not it is fine. I just edit in a second program to fix the distortion. Not the end of the world. So apologies if any offense was inadvertently caused and I changed my wording and hope that is not misunderstood.
Hey, I just wanted to chip in saying that I agree, pincushion/barrel distortion correction is something I miss in DT. There have been numerous instances just in the last couple of months, last one being today. I am aware there are probably workarounds, but I am not skilled enough to implement them (I am usually shooting with lenses that don’t feature in the lens correction module offer) and I would generally enjoy a manual slider for that as well. And I’d like to defend Terry on top of that, in no way was he being manipulative by saying it is a “shame” that that feature is missing. What he was getting at was that such a good and thoroughly capable program as DT is definitely capable of hosting such a feature, and I second that. No need to misread that.
Use the mode option to switch between barrel/pincushion, use the mm number to change the amount of pincushion/barrel distortion, use the scale slider to make the image fit, use the target geometry as a sort of extra “flavor” of the distortion. Play around a bit, find what suits you, save that as a module preset, I am sure that with this youre gonna fix or distort the wildest of lenses.
Hi @Terry , you maybe remember I’m also very interested in such an option/module. I use old manual lenses a lot on my fullframe Sony camera and missed a good option for correcting distortions. It’s a pity my son didn’t help us out with his programmers skills and he’s too busy now in his job.
But @bazdesh I’m impressed. How come you found out that option? The idea feels a little crazy, but … it works. Thank you for that hint. I made a short test and will try it on some real images.
I was looking for a way to fix one of my anamorphic lenses, it was - of course - nowhere to be found, so instead of setting up a profile, I started playing around with the existing ones and eventually found the “generic” section, I am 99% sure that it exists for this exact reason (weird lenses with no profiles), but I just guess its one of those easter egg features. Lets say it was my laziness
@bazdesh thanks for this tip. I presume I will be able to make a preset that will match my manual lens that are not in the database. It probably also suggests that if a developer is interested in adding a distortion control that maybe this generic lens will demonstrate an easy path to implement it.
The workaround is cool, but there is a precedent of LR’s uniform distortion which comes as a single integer slider. Boutique lens reviews often contain stuff like “dial +5 to correct the distortion”.
Whenever I make a suggestion about improving something in DT I appreciate that this is always the case. I don’t have demands or even expectations for features I suggest being developed. I just hope that some developer might share my interest in a feature and create it.
There is so much good development happening at the moment and appearing in the master. I am always blown away by the rate of evolution and development in DT. I don’t remember any program paid or FOSS which has such rapid development of new features.
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