Optical corrections 6.3

I just noticed a different behavior with optical corrections. I noticed this first with a picture in another thread Off-Topic - advice, experiences and examples, for images that will be processed in PhotoLab - #1278 by George

Since 6.3 the automatic cropping based on keystoning is no longer applied.

But this behaviour isn’t constant. And off course only visible with the shorter focal lenghts. This one was 28mm.


Hi George - you may be interested to see this relatic topic/thread. My apology if you already have seen it.
Glitch in DXO PL 6.3.0

Hi George,
I played with 2 different raw-files – and it is very obvious with a fisheye lens.

When PL6.3.1 Build134 ( = Windows ) ‘discovered’ the new pics
my unaltered standard preset “1-DxO Standard” showed in both cases

Screen Shot 02-12-23 at 11.47 AM

which includes “Crop / Autobased on keystoning / ho …”

Checking with the presets shows


When applying “2 - DxO optical corrections only”

the Crop tool (and so Autobased …) was not activated

→ As “Constrain to image” is not part of any preset, we see the exterior black parts. ←


I haven’t seen it. Well, that explains it. Thanks.


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I’ve some 15mm images too. What I don’t like is that a reset doesn’t reset everything. An image once opened in an older version of PL shows only the “optical corrections only” without a crop correction, all the others are with crop correction.
Exporting this image to another directory and opening it shows all the presets without crop correction.


Yes - This changed behaviour is most unfortunate.

Pre-PLv63 the automated default was to “Constrain to Image”. Now, with PLv63, this is a user-decided choice - BUT, the default is set to “(Do NOT) Constrain to Image” … which is the opposite to the previous behaviour.

I suspect this was an implementation mistake - due to the confusing state of the setting within the Preset files … where the OFF-state for this setting is “True” !!

@Barbara-S … Might this be added to the list to be fixed, please.

John M

If this issue is not to to be added onto the “Fix” list, then how are we to revert to the previous behaviour without going to each frame to change the crop options?

What exactly does constrain to image mean? When I tick the constrain to image box it just fills in the missing pixels removed from the optical corrections. For example with optical corrects applied the image is 5776-3843 with the constrain to image box ticked it’s back the native sensor resolution of 6048-4024?
Should I leave this box ticked or unticked?

The process to change PL’s behaviour (to the previous default) is described here.


The best way to understand it is to see the result … See Wolfgang’s examples above.

As @Wolfgang notes; If “Constrain to Image” is not activated you will see the “exterior black parts”. If it is activated, an automatic-crop will be applied to keep any “black parts” outside the cropped area.


Many thanks!

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With the default Dxo standard present Constrain to image is not activated, Dxo optical corrections are activated and I can’t see any black areas however resolution is slightly reduced. This makes sense to me as the software has stretched the image and has cropped out the black areas. however if I activate constrain to image the image magnifies in slightly and resolution increases back to native sensor resolution so my question is if the optical corrections have already cropped away some resolution how is resolution now being added back despite having already being cropped away?

I can’t quite follow your description, Hayden - but, the result from “Constrain to Image” is also working in conjunction with your Crop settings - and whether they’re Auto or manual, etc
image - play with these and see if it makes sense.


sorry I probably didn’t explain it Very well.
Have a look at the two Screenshots
Note the resolution of the first screenshot which I understand is from the cropping of the image due to the optical corrections being applied.
second screenshot the optical corrections are still applied so the image has been cropped and resolution should be the same as the first screenshot but the only difference is constrain to image box has been ticked which for some reason causes the resolution of the image to increase back to what it was before optical corrections and cropping was applied, is this what its meant to do? if so what’s causing this? is the software upscaling the image back to pre crop resolution?

Yes, thanks - the screenshots helped … I get it now.

Firstly, my explanation is incomplete …

It should be;

  • If “Constrain to Image” is not activated you will see the “exterior black parts” - including any parts of the image that, due to distortion correction, are outside the crop boundary.

  • If “Constrain to Image” is activated, all parts of the image outside the crop boundary (due to distortion correction being applied) are hidden - you don’t see them.

Also note that “outside the cropped area” is defined by the Crop tool settings, and constrained by the “Keep Aspect Ratio” setting in the Distortion tool.

To better see this in action (referring to my screenshot above);
– Activate the Crop tool … and toggle “Constrain to Image” …
– also try changing Crop’s “Aspect Ratio” setting to Unconstrained, etc

As a general point; No - PL never upscales (as in creating pixels that didn’t previously exist).

HtH - John

From what I see, there’s a difference between crop and constrain to image.
If distortion is activated, an optical correction is applied.
Cropping means just cutting out the black parts. The image gets smaller.
Constrain to image means enlarge the image so that the black parts are out of the image. Due to the fact that the heigth and the width aren’t equal the aspect ration is altered a little.
Keep aspect ratio, well just means keep aspect ratio. The size of the image is the original size with the same aspect ratio.
It might help if you watch the move/zoom window. There you can see it happening.


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Oh well, I never looked for that. You are right – see post #16 by George.

The final test is to export from the optical corrected and cropped raw-file

  • without Constrain to image
    → resolution scaled to the ‘inwards’ sections of the optically corrected and then undistorted pic

  • with Constrain to image
    → resolution scaled to the ‘outer’ sections … ( = the original sensor resolution )

That is – you have the choice. :slight_smile: