Using 'Compare' to see JPG vs RAW -- they're not aligned

I don’t remember this always being an issue, but when I select ‘Output>JPG’ as the comparison target, the JPG image does not replace the original as the same size. It doesn’t matter whether I’m zoomed into the original image or zoomed out to show the whole image, the JPG is not aligned to the original.

Perhaps it’s just my setup, but that’s one of the things I’d like to find out. If it’s not just my setup, then is it really particularly difficult to write the software to find the display setting (zoom setting) of the original and then find that same area on the output image? My output aspect ration is the same as the original.

I frequently like to compare images by snapping each into place with perfect alignment so I can see clearly what’s different between them at the moment of the switchover.

Photolab 4.3.0 build 5480 (same problem for over many past revisions)
Win10 Intel(R) Core™ i7-7500U CPU @ 2.70GHz 2.90 GHz
Generic PnP Monitor (1920x1080@60Hz)
Intel HD Graphics 620 (Samsung)
2048MB ATI Radeon 540 Graphics (Samsung) (enabled in Photolab)
CrossFire Disabled

Thanks in advance.

I recently reported two related issues to DxO. One is that same-size exported images (JPEG or TIFF) don’t align perfectly, pixel-to-pixel or size-to-size, with the source image in the image preview window during a compare. That seems to be the same problem you’re describing - and I agree that it should be fixed. The other, clearly a bug, is that the position of the zoomed-in preview can be different between the source image and the exported image if the source image was taken in portrait orientation.

At which zoom level are you having this alignement issue? Below or above 75%?
I ask because below 75% the rendered image in the viewer is slightly different from what is rendered starting at 75% and above…

Below 75%, some algorithms (read: corrections) render with a “lightweight” mode, because below that threshold, rendering the image at full-quality vs slightly lower quality would be indistinguishable to the eye…(and this of course allows PL to spare some computing tasks). If you set your zoom level to 75% or more, the image preview is rendered at full-quality.


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Ok, here’s what I see now with a little experimenting.
Using the same source RAW photo, it doesn’t seem to matter what my zoom setting is (higher or lower than 75%) when I perform the crop and then compare the output to the original (nor if I change the zoom % after cropping too).

However, using the same source RAW photo, it seems that some “random” crop sizes do align properly and other “random” crop sizes do not properly align (mismatching by enormous amounts sometimes)
[But now I’m having trouble repeating the “randomly” working crops – JPG output are typically zoomed-in further (much larger) than the original]
Also, if I reset the crop the output JPG almost aligns with the original but still there’s a slight size difference between the two which creates movement during the switchover regardless of zoom setting.

Also, once again, I finally got a crop which did align with the original. And then I moved that crop without resizing it (I verified the size), and then it no longer aligned when compared. Difficult to find the original location where that crop actually worked okay in terms of aligning with orig

And, if I set the crop size to be as close as I can get it to the pixel count I’ve set all of my output to become (scaling to same pixel count no matter what size crop), at least in the trial that I tried, the output matched the original very closely at 75% zoom and higher (and at lower zoom % too). I tried moving that 1:1 crop (output same number of pixels as crop size) around all four corners and the center and the output JPG remained in alignment with the original (only scaling down from 5404 x 3603 crop → 5400 x 3600 output)
Then when I tried 5399 x 3599 crop → 5400 x 3600 output, there was absolutely no shift no matter what the zoom value. Whereas with the previous crop of 5404 x 3603, there was the slightest amount of movement switching/comparing between output and original for all zoom values.

Thanks for the details. I’ll try to reproduce it on our side.

Hi @BBT,

Thanks for the details. Could you send us a RAW image + sidecar + exported JPG so we can reproduce the exact problem on our side.


@gpailler Files are uploaded with your name as the ticket #. When I use COMPARE for this RW2 raw file to the JPG output, the JPG output zooms in a little bit further such that the RW2 and JPG images are not aligned, and the narrow strip of top & bottom margins around the image gets even narrower for the JPG image (side margins in the viewing area do not seem to change tho). Similar behavior occurs whether I undock the image navigation/selection strip from below the viewing window or whether I increase the height of the image navigation/selection (the margins around the image within the viewing area will change depending on height of the navigation/selection strip – and then the side margins might be the margins that change when comparing instead of the top & bottom margins).

[added note_01: What I described above in this same post is when I’ve set the zoom for the RW2 image to view the entire image within the viewing area which auto-chooses 22%. Then I click the COMPARE button and the JPG image replaces the RW2 image as described here. And it’s similar at the other zoom presets – for this photo JPG is very noticeably always a [significant] bit more zoomed in than the RW2 and that might be the case for all photos and all zoom values but I haven’t made a point of determining that]

[Added note_02: When I leave the zoom set to the auto-chosen 22% for filling the viewing area with the RW2 image, and then select (not Compare) the related JPG output image to be displayed, the zoom auto-chooses 20% without me manually doing anything to the zoom setting – and then the JPG image does align properly with the RW2 image – no jump in the image when switching between the two for the photo I uploaded to DxO. Zoom returns by itself to 22% when I return to selecting the RW2 image. So, the zoom value is less for the JPG and yet when the JPG is compared to RW2, the JPG appears as though its more zoomed-in – larger. A simple explanation might be that the same zoom setting is used for the RW2 as for the JPG when the zoom should change (e.g. 22% to 20%) when viewing the JPG during Compare)

Thanks, the issue could be related to a specific body/lens combination. We will try to reproduce on our side.
@sgospodarenko Could you check and create an issue please?

Yes, sure.

Update: @BBT some more questions:
1 - have you enabled Resizing in your output settings window?
2 - could you, please, make a small video/gif to display the issue?

Thank you
Svetlana G.

@sgospodarenko: Sorry, I didn’t notice your request until now. Yes, as I mentioned above in an earlier post, I have the export set to resize for longest side to be 5400 pixels (short side becomes 3600 pels). Would you still need that video? And as I mentioned above, I’m betting it’s related to the fact that my JPEG output fits the viewing area using a different zoom than the RAW uses to fit the viewing area. The JPG doesn’t require as much zoom – so if the RAW’s zoom value is also applied to the JPG, then the JPG will become larger than the RAW being viewed during Compare.

[Update: I just installed latest revision 4.3.1 and the Compare seems to be much better. Not sure if you intentionally want the JPG to be a slightly smaller size than the RAW as a means to know the image has surely changed, but I do prefer an exact match so it’s very obvious what’s different when only the difference appears to change and not the whole image size (slight as it is now). If you didn’t do anything to address the [previously] poor match during compare of the Raw vs JPG, then I’ll put more time into helping resolve that if I see a very poor size match again. Perhaps you intentionally made the JPG slightly zoomed out more (so image appears smaller) than the RAW cuz it isn’t always possible to make them align precisely, so you chose to never make them align precisely to avoid it behaving differently sometimes than other times]

Good morning,

Thank you for the feedback. Please, let us know if you face the issue again.

Svetlana G.

@sgospodarenko Turns out that the problem is still present. After updating to 4.3.1, I had only tried a few photos before reporting that something seems to be working better.

Turns out that the ones I had tried were not cropped at all or not very much. And the Compare seemed kinda close but they weren’t aligned identically by a very perceptible jump even tho only a slight misalignment.

It seems that when there’s cropping of more than a little, the JPG view is significantly far off from the RAW view during Compare.

I uploaded 3 different videos (two different crop sizes) with your name as the ticket#.
[Update: I just noticed I have to click “Start Upload” before clicking “Send” at your upload page. So I’m not sure I clicked that for the previous 2 videos I thought I had uploaded. I’m uploading those again to be sure you have them]

(By the way, you can also see that the image isn’t updated quickly when I go into crop mode – black viewing area for many seconds with only the crop outline showing).

I haven’t tried lots and lots of different crops, but it seems that the more that is cropped away, the worse the alignment during compare.

If you’d like me to record anything specific, let me know.


Thank you, Brian.

I’ll have a look at the files.

Svetlana G.