Affinity photo stack - halos

[kevin_beretta]

Hi all,

I gave Affinity Photo a try to stack photos. The image below is a stack of 170 pics with a D850 and a 105 f/2.8 Micro Nikkor. I get a weird halo at the top of the stack. I tried a few iterations but that halo seems persistent. Any insight as to what may cause it?

Thanks,

Kevin

[kevin_beretta]

2 minutes ago, marc epstein said:

I really am not familiar with affinity stacking but based on other experience, it might be from a size change in 1 or more of the exposures (?) or from an out-of-order in the one of the stacks (?).  I’ve had that happen to me in other programs.  Just a few thoughts.

A size change based on the incremental focus creep? Guess that could happen with some lens aberration. They were not out of sequence, that much I know. Guess I'll hold off on Affinity for now. Thanks for the feedback.

[paddler4]

Magnification changes when you change focus. All good stacking software adjusts for this if there is no gap.

This looks like something different to me. When there is a substantial distance front to back between an edge and the surface behind it, stacking will often create halos like this. Some stacking algorithms have more severe halos than others. For example, in the case of Zerene, which is the stacking software I use, the PMax algorithm has much less of an issue with this than the DMap algorithm, so when I have reason to use DMap and the image has this problem, I do a second composite with PMax and use that to repair areas with a halo. I have no idea how Affinity stacks, but that cold be the problem.

Why did you take 170 images? I have never had to stack more than 25, and often I end up with far fewer. And that's with being conservative, erring on the side of too many (to avoid having a gap). 170 images would be appropriate for extreme macro with very high magnification, not for something like this.

[kevin_beretta]

I guess my thinking was that more pics was better/easier to get a smooth end result. I've used Zerene before and I may need to get back to it. It's a shame Affinity did not work. I did something similar with Zerene a few years ago and it was sublime. Thanks for the info!

[paddler4]

Quote

I guess my thinking was that more pics was better/easier to get a smooth end result. 

Not in my experience. The key thing is not to have gaps--that is, to have enough slices that everything is in sharp focus in at least one image.

I have used Zerene exclusively for stacking for many years, and I love it. 

[conrad_hoffman]

I've done a fair amount of stacking in Affinity and it usually works great. I rarely use more than 15 images. I've had halos around bright hardware on aluminum parts (I do a lot of product photos) and had exactly the same problem with other stacking software, so I'm thinking its an input problem, not a software problem. FWIW, I've had a similar problem with stitching software on similar subjects.

[kevin_beretta]

I'll reshoot it with something else and see what happens. Won't be for the immediate future... life is getting in the way...