Photo Focus Stacking (Macro)

Focus stacking merges 5–500 frames shot at different focus distances into a single image with extended depth of field. Mostly a macro and product-photography technique, occasionally landscape (foreground-to-background). Different from exposure-blending (see Panorama & HDR) — same idea, different axis.

Free / OSS

• ★ Hugin focus stack workflow — Hugin + enfuse is a complete free pipeline (align_image_stack → enfuse --exposure-weight=0 --saturation-weight=0 --contrast-weight=1 --hard-mask). Not a one-click tool, but the canonical OSS recipe; scales to hundreds of frames.
• ★ Picolay — free, Windows-only; written by a hobbyist; surprisingly good output, batch-friendly. Long-running, still maintained as of 2024.
• CombineZP — free, legacy Windows; the original hobbyist focus-stacking tool. Still works on modern Win but unmaintained.
• enfuse — see Hugin above; the underlying CLI you can drive from a script.
• darktable — has no built-in focus stacker; some users script darktable + enfuse together.
• GIMP Focus Blend — script-fu plug-in; manual but free.

Paid / commercial

• ★ Helicon Focus — paid perpetual or subscription. The pro pick for macro / product shooters; three stacking algorithms (A/B/C), Helicon Remote tethered shooting integration, retouching brush for halo cleanup. Long-time gold standard.
• ★ Zerene Stacker — paid perpetual. Beloved by serious macro shooters (insects, focus-stacked microscopy); algorithms (PMax / DMap) often produce fewer artifacts than Helicon on hairy / fine subjects. Slower, but usually wins on quality.
• Affinity Photo Focus Merge — paid one-time; included with Affinity. Decent for casual stacks; not in Helicon / Zerene's league for difficult subjects.
• Photoshop Auto-Blend Layers (Stack Images) — included with Photoshop subscription. Works for shallow stacks; struggles past ~20 frames.
• CaptureOne — no native focus stacker; pair with Helicon.
• DStretch / Image Combine — niche.

In-camera / computational

• Olympus / OM System "Focus Bracketing" + "Focus Stacking" — the camera captures the bracket and merges in-body. Surprisingly usable up to ~15 frames.
• Nikon Z / Canon R mirrorless — focus shift / focus bracketing built in (capture only); merge externally.
• iPhone / Pixel macro mode — computational; not a true focus stack.

Workflow tips

• Tripod and a focus rail — manual rail (Velbon, Manfrotto) for cheap, motorized rail (StackShot, WeMacro) for serious work.
• Disable IS / VR — vibration reduction can micro-shift frames between captures.
• Aperture choice — diffraction limits sharpness; f/5.6–f/8 typical for macro stacks (not f/22).
• Step size — depends on aperture and magnification; 1–2× DOF overlap per frame is the rule of thumb.
• Halo / fringe cleanup — Helicon's retouching tool, Zerene's "Retouching" brush, or manual masking in Photoshop.
• Stack count — insects 30–80, product 20–50, landscape 3–10.

Pick this if…

• Free pipeline, scripting OK: Hugin + enfuse + align_image_stack.
• Free GUI, Windows: Picolay.
• Pro macro / product, daily driver: Helicon Focus or Zerene Stacker.
• Hard subjects (insects, hair, fine fibers): Zerene Stacker, often outperforms Helicon.
• Already in Affinity: Focus Merge is "good enough" for casual.
• In-camera, no post: OM System cameras.