Correction of distortions

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Correction of distortions


today I was testing the conversion of RAF-files of the Finepix X-S1. This camera has an EXR-sensor with a special layout. Earlier versions of lightzone converted this RAF (Fuji RAW file type) pictures but with an ugly blueish cast. This is now corrected, surely because of the newer dcraw version.

There are two questions I want to ask here ...

1.) the X-S1 has a 12 MP sensor, but because of the (non Bayer pattern) layout decoding yields always 6 MP pictures. I think this will not be changed in the future?
2.) the superzoom lens of the X-S1 causes partly strong distortions, especially in the more extreme focus ranges. Do You intend to correct this behaviour (f.ex. by using the lensfun library)?

Best regards

In the first case, i am not

In the first case, i am not sure we will be able to "fix" this, but I'll let one of the Dev team eventually weigh in on this one. On the second problem, i very much doubt we will have the resources to ever create a lens library. Whether we can use another is an open question. I think we may be able, in the future, be able to have lens corrections....although, I think that is a raster operation, and LZ is a vector program...


Very much it was pleasant as your program works with RAF-files. I have a camera Finepix X-S1. Unfortunately, when converting it is possible to receive the maximum size 2848х2144. Whether there is a method to receive the size 4000х3000? Or while for this sensor it is impossible? The dcraw 9.16 installation didn't solve a problem...

As far as I know, this is an

As far as I know, this is an issue with dcraw---the program we use for primary demosaicing.  I don't think there is anything that we can do about it....You can try the latest beta to see if some change has been made, but I doubt it.

It is slightly different with

It is slightly different with my old S9000 RAF pictures. This camera (purchased in 2005) provides 9 Mpx JPEGS. But when you process the raw files with the bundled Fuji software, or with the old s7raw freeware, or with RawTherapee, I get  pictures over 17 Mpx, due to the non-Bayer sensor, whilst all other software are limited to 9 Mpx. The 17 Mpx size is a sort of bonus which I think was not even specified in the camera features (in 2005, 9 Mpx was already great!).

But, as RawTherapee can also process new X-Trans pictures, I'm sure it would process your raw files in 12 Mpx.

Lens distortion and correction?

I have a similar question. When I export images from my Sony ILCE-6000, it comes out with lens distortion/vignette effect. I believe, from what I've read on the forum, that LZ doesn't have the correct lense information to make the proper distortion correction. Is that true? In that case, does it render LZ useless to me, unless I want to live with the distorted images?




Distorded images could be

Distorded images could be corrected with another software after Lightzone Post-treatment. I'm not very concerned about distortion since my lenses have very few ones, but sometime I correct perspectives with Digikam after I had working on picture with LZ. 


It's not a perfect way, but it's a possibility


For vigneting, you probably "simulate" a kind of correction with a lightzone tool. 

PT Lens

For Windows and Mac users there is a quite cheap program called PTLens that does quite a good job at corrected distortion. It can work standalone or as a plugin to quite a few programs.


Main page for the program:

Supported fix lens cameras:

Supported interchangable cameras & lenses:


The current version is 9 (not 8.7.8 as shown on the screen shot on the main page), the links to the reviews are quite old, but give you quite a good idea of what the program can do.




For completeness I will mention that it might happen that LightZone will use the Lensfun library for lens correction. See

It is a open source library that delivers the data needed for corrction. If your lens or camera is not supprted look here and make it supported by taking a few pictures. It means that you can help ourself, one of the joys working with OpenSource.


Have a nice day

Lensfun integration (and

Lensfun integration (and perhaps a better noise reduction, Masahiro said he was looking at) would make LZ a very well-rounded editor. It was (Lensfun) recently updated and works quite well with programs, that are using it. RawTherapee uses Adobe's profiles, but if I remember correctly, they are also planing to migrate. But, I suppose, that kind of improvements work best with a dedicated developer or a team, working just one thing at a time. All the OS- and java-related fiddling consumes a lot of time.


Have a nice day!



CA correction

CA correction is another tool that a well-rounded editor and raw converter should have.

LZ - as it is - is already a very fine piece of software but there is still some room for improvements. 

Regards, dke

I agree

Some of Lensfun's profiles include CA correction data, many don't. A dedicated LZ tool would be quite an improvement. Doing it manually is fun, but not perfect and it certainly is time consuming.





Personally, I've created a

Personally, I've created a style to correct CA.


Basically, it consist in 3, 4 or 5 "hue/saturation" tools, each for a specific hue to desaturate (pink, violet, purple, cyan, green) .


After that, there's just few tweaking to do in the hue range setting and I found the result nice enough. 


I should post it in style part of the forum.

Post it,

certainly, most likely it will not become the default CA-correction tool, but it will be tested by some users when still warm. Desaturation is supposed to be a kind of a roughh approach, as far as I know, channel-related corrections (during demosaicing?) being the real stuff. As you can see, this is far beyond my "expertize".




Lensfun again



I know I am repeting myself. If you want to help with distortion, CA correction data and vignetting you can help to get Lenfun to support your Cameras and Lenses. It is mostly abot taking a few pictures of a building with stright vertical and horisontal lines. I have done it myself for those of my lenses that was not supported. Its easy, and you are helping yourself as well as others. Look at and for information and instructions


Once again


Have a nice day  ;-))




repeating yourself certainly doesn't harm, au contraire, but I think I can, with some programs, get better results using the CA tool before demosaicing, than when using the CA data, included in lens profile, afterwards. I certainly do support improving open-source projects as much as one can, though. And I am sorry if this makes no sense.


Be well!




There's already speak about

There's already speak about using LensFun in Lightzone. I suppose it's still in progress with the few time could spare the developper(s)  who are already doing a great job but are not numerous.