Stack unexpected results, areas missing

[bbiesele]

Mac M1 mini; Mac OS 14.4.1, Affinity Photo 2.4.2. Doing a new stack the median and minimum modes produce a result with unexpected black areas. First attachment is a catalogue view of the inputs, only the JPG's were stacked. Second and third are failed stacks. Fourth is using Maximum mode which does not have the failure. 

[bbiesele]

Canon EOS R8 Firmware 1.2.0

[Dan C]

Hi @bbiesele,

Thanks for your report & our apologies for the delayed response here!

Unfortunately I'm a little uncertain of the exact issue being raised - are you referring to the brown triangle shapes in the top right of your stacked images please? 

[bbiesele]

The dark triangle in all three shots was there. It was a simple straight line from one edge to the other. The attached picture has the created shape marked. Compare this to the last file uploaded in the original post. The stacking operator in the correct picture is the down arrow (maximum).

[Old Bruce]

This is just the way the Stacking works. Look at how the power poles are thicker in the Minimum vs the Maximum shots. It is just how this works.

   

[Dan C]

19 hours ago, bbiesele said:

The dark triangle in all three shots was there. It was a simple straight line from one edge to the other

Thanks for confirming that for me - as Bruce mentions above this is simply how the Stacking functionality works.

It appears as though your source images were not taken completely static (ie using a tripod) and therefore when the Affinity app is stacking these images, the app has to transform, scale and rotate the source images, such that all of the main subjects within the shot, like the gate in the above screenshot, line up as best possible.

When doing this, the triangular section in the top corner of each image is therefore not in the same position for each image, causing an overlapping / stair stepping effect. Unfortunately this cannot be avoided based on your source images.

I'd either recommend cropping this section of the image out of your Stack, or when taking images for your next stack you could use a tripod to ensure that the cameras viewpoint remains static, allowing the app to stack images without needing to transform, scale and rotate