DNG export Denoise & Optical Corrections only is applying distortion correction when it has not been applied

Hi All

I exported a DNG from Photolab using the “Denoise & Optical corrections only” option and before export only applied DeepPRIME XD (no distortion correction, no default presets, nothing).

I edited the DNG in Lightroom and also edited the original RAW because I wanted to compare the denoising results. I applied Lightroom’s distortion correction to both images (among other edits)

To my surprise, even before editing and applying Lightroom’s distortion correction, the original RAW and DXO’s DNG of the RAW have very different distortions. Of course, those differences remain after Lightroom’s lens profile corrections are applied.

Does anyone know why this could have happened? I never applied distortion correction in Photolab so it should not have been included in the DNG.

If my understanding of what you did is right, this is normal.

DNG already has distorsion correction (you applied Photolab optical corrections), but raw file is is the output of the camera without any change (without processing of any kind).

So you applied distorsion corrections twice on DNG file : photolab + lightroom (you shouldn’t have applied them in lightroom to get right result).
But raw file only had them applied once : lightroom.

Thanks for the reply. Although the name of the export option is “Denoise & Optical Corrections only” my understanding was that this option only exports with denoise and optical corrections if I have actually applied those in photolab. I did not apply any optical corrections, only denoising.

Is that wrong, does this export option always apply optical corrections irrespective of whether you have applied that option before export?

I do not use this option for export, but I think it’s the counterpart inside photolab of pureraw and it’s done to use DxO strongs points in other softwares (denoising and optical corrections), so it would make sense for me that this export apply them and only them in any case.

Suggest checking whether a DxO Optics Module correction was automatically applied before export.

No, I made sure no optics modules, nothing whatsoever, was switched on. Only DeepPRIME XD.

This is confusing, so it’s impossible to export a denoised DNG from Photolab without also applying lens distortion correction? Seems odd.

I tried the other DNG export option (all corrections applied) for comparison, making sure to leave every single module switched off except DeepPrimeXD, and it still applied distortion correction and also changed the colours.

I don’t think you indicated which version of PhotoLab you are using or whether you are on a Mac or Windows 10/11.

I am using PhotoLab 7.22 on Windows 10 and can’t recreate what you are seeing.

As an additional test, I suggest that you first apply the No corrections preset to you image, which will deselect all active corrections. Then select only DeepPRIME XD before exporting the file again using “Export as DNG (Denoising and optical corrections only)”.

If you get the desired result after this test then it is probable that you had Distortion correction set even though you believed you had deselected it.

If you get the previous result and distortion is still being applied then it is likely there is a software corruption which can be fixed through a Repair reinstall.

If you are on Windows, to fix a software corruption, reinstall PhotoLab over the current version and select the Repair option. After reinstalling test again using the No corrections preset first. If you are on a Mac I have no idea whether a repair option is available.


When you see the distortion corrections and color change, is this in PL7 or is this in LR on return of the DNG?

and also changed the colours.

In PL 7.7.2 I applied the preset “6 - No correction” on a file,
which comes with lot of distortion.

After DNG export (Denoise & Optical corrections only) I got

In a direct comparison I couldn’t see any optical corrections applied,
but brightness had changed !

Repeated the test with a different file/camera … same thing.

Distortion correction is part of the optical correction.


Thank you for all the replies. I have now worked out what is happening but I was actually mistaken and the issue is different issue to what I thought it was.

Photolab is not applying distortion correction. I was mistakenly comparing both the DNG from Photolab and the original RAW in Lightroom with Lightroom’s distortion correction applied and there is a radical difference in the results. With Lightroom’s distortion correction off, both the DNG and RAW are the same.

This leads to a different question: What is Photolab doing to the DNG such that Lightroom applies such radically different (and wrong, to my eye) distortion correction to it as compared to the original RAW?

EITHER use PL’s optic modules (incl. distortion correction) OR the equivalent in LR,
but never on both sides – to avoid double ‘correction’.

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That’s right, I didn’t. Only Lightroom’s. But Lightroom applies different corrections to the dng from dxo and the original cr3, which is strange.

Are both the same size in pixel ? In lightroom ?

Yes, both the same pixel size (6960 X 4640)

The DNG from DxO is not a raw file, it’s a linear RGB file.

All that use of DNG is causing more problems then that it solves.



I’m not sure whether this is an academic question or a search for a new workflow. If the former, it should not be surprising that LR or PL treats a RAW file differently than it treats a demosaiced linear DNG. PL did its job correctly making optical corrections (or not) in the exported linear DNG.

If a new workflow is contemplated, a link to the DxO recommendations can be found here:


If LR is to be the main editor, the usual workflow would involve making both denoising and optical corrections in PL (or PR). The optical corrections applied in the DxO programs are usually superior, so I do not understand the rationale for making them in LR – maybe an experiment? As Wolfgang cautioned earlier, make the optical corrections in PL or LR, but not both, and I would add not splitting optical correction and denoising duties. Go one way or the other. My $0.02.

In the crop or distortion module (Can’t remember which, and I’m at work) is a checkbox to ‘constrain’ or something. If you really want the pure unaltered, leave that off (or play with it to check the differences).

It could also be a case where Lightroom applies built-in crop and corrections automatically to the RAW file, but not to the DNG because it doesn’t recognize it at the same (or the built-in corrections have been stripped out).

For what it’s worth, I never have this issue with my (older) Olympus and Sony cameras.