large panorama stitching fails to complete

[mgg@mac.com]

I have a series of jpg files shot with Dwarf II telescope using PANO landscope mode.  When I attempt to load the entire set 270 images it creates a mess of a pano. These images are clean, about 40% overlap. If I use a subset - say 120, it stitches fine.  All the images are fine, they can be loaded and viewed in other programs.  the images are 3840x2160.  Is there a physical limit to what can be handled?  LR won't stitch either.  No errors, just botched output in PS and hung processing in LR.  This is a just few monhts old loaded Mac Studio, so cpu/memory/disk resources isn't a problem.  

[Semaphoric]

What type of subject are they? Photomerge can have trouble aligning images of stars.

[mgg@mac.com]

Grand Canyon landscape

[Semaphoric]

I had some difficulty stitching some larger (for me) panoramas a couple of years ago, with both Photomerge and a third-party program, but I chalked it up to my old computer being underpowered. I ended up stitching smaller areas, and then stitching the results together.

I do not know the actual technical answer to your question, and I hope someone who does know can answer, as I am curious also.

[mgg@mac.com]

I took the pano files over to Affinity Photo and processed there, successfully.  There was an issue however, a gap in the images on the left side between rows (someone must have kicked the tripod 8^/ ).  I still would have expected LR or PS to error out like they normally do if there is an issue with the source images, not spit at 100% CPU overnight and never finish or quit.

[D Fosse]

Just so we know what we're talking about here - what is the approximate pixel size of the finished pano?

How much disk space do you have for the Photoshop scratch disk? I know you say Affinity manages to do it, but this may be at the limit of I/O capacity and there may be differences in memory management between the two apps.

From what I can tell, this will be a massive hit on the scratch disk and you're probably looking at several terabytes. RAM and CPU is pretty much irrelevant here.

[mgg@mac.com]

ok, we are on to something.  I currently have only one drive, system, 1TB.  It has 800G of free space but scratch disk in PS says it can use 135.... seems odd, can't seem to change it.  I can connect another external drive, which of course will be slow but will have plenty of space.  Still why didn't something complain?

[D Fosse]

OK, that's it then. 135 GB is nowhere near enough for this. Even 800 would probably be a struggle.

In this case I'm impressed that Affinity manages to complete this at all. They must use a completely different mode of operation for panos.

Anyway, if you routinely work with these big files in Photoshop, you need more disk space. I have 2TB primary scratch on fast NVMe, and 4 more on a spinning drive just in case. That will be slow, but it will keep Photoshop running no matter how big the files.