Offset bug with Auto-Align Layers

[jfm35051248]

I don't understand why Auto-Align Layers does not work perfectly when aligning two versions of the same source.  Here is what I did :

1. I have an original image in Lightroom.  Version A
2. I create a virtual copy of this image, I rotate it 7 degrees and crop it smaller. Version B
3. I select both images and right-click open as layers in Photoshop.
4. I lock the layer containing Version B (using the "Lock all" padlock icon) because I don't want this layer to be rotated.
5. I select both layers
6. I execute Auto-Align Layers with Auto option
7. Photoshop successfully rotates my Version A to match Version B, but fails to align it perfectly.
8. I need to nudge Version A a few pixels in both directions (using 50% transparency as reference) for it to align perfectly. 

This is clearly a bug.  Any help?

[c.pfaffenbichler]

Can you provide the files? 

[D Fosse]

I've noticed this too and can confirm. Auto-Align has occasionally done this from the start; it's not new.

Personally I'm not so bothered. It's often necessary to nudge a bit anyway. Because of optical limitations, two frames may not be aligned at the sides where you need it, even if perfectly aligned by frame center. So I routinely check at 100% and nudge when necessary.

But yes, it would be nice if they fixed this. When it happens, the alignment is in fact perfect, just offset by a couple of pixels.

Take it to the feedback forum. Link at the top of the main page.

[jfm35051248]

Thanks D for your feedback, but unfortunately this is not an acceptable answer.  Many photography techniques require precise pixel alignment of multiple images for later combining using mean or median filters.  It makes absolutely no sense to review and realign all these layers by hand when Photoshop simply fails to compute the math correctly.

I attached two sample images (as well as the result).

I can reproduce the bug every time :

- Open the 2 files as layers

- Move TestB on top

- Lock TestB layer

- Auto Align Layers

- Unlock TestB layer

Now set layer mode to Difference to see the anomalies.  The result should be a black rectangle inside, which I can only obtain if manually nudge the layer by hand.

This is really an unexpected bug from a professionnal software and should be fixed.  

Until this is fixed or a workaround can be found, I need to look for an alternative software that can successfully align many dozens of images seamlessly for stacking techniques (any suggestions?).

Thanks,

[c.pfaffenbichler]

The unsatisfactory result also happens here, so no argument that this may deserve attention from the Photoshop team. 

I wondered if Auto-Aligning a second time, this time with »Reposition«, might work out but that seems to provide a nonsensical result. 

A link to the page @D Fosse mentioned: 

Photoshop Family

[jfm35051248]

Thanks for pointing the link, I just did so. Best,