Sometimes, the stacking process leaves artifacts (e.g., haloing, ghosting) where the algorithm couldn't figure out which part of the image was in focus. Go to the tab.
Deep stacks, complex overlapping objects (like a tangle of insect legs or dense botanical details), and shots with significant exposure variations. helicon focus user guide
If you spot artifacts, halos, or missing sharp zones, use the internal retouching tool: Switch to the tab at the top. Select the Texture from source brush tool. Sometimes, the stacking process leaves artifacts (e