Autostack

Autostack is a batch tool: point it at a folder that contains several focus brackets and it splits them into separate stacks — grouping the images by capture time — then stacks each set automatically. It’s the fastest way to triage a card full of brackets and see which ones are keepers.

Opening Autostack

Two ways in:

Click the ⚡ Autostack button in the Library mode bar, next to the wordmark.
Or choose File → Autostack a Folder… from the menu bar.

Either one opens the setup window.

How it works

Pick a source folder — the folder that holds your brackets. Autostack scans it and groups the images into focus-bracket sets by capture time: a run of frames shot close together becomes one stack; a gap in time starts the next. It looks at the images sitting directly in that folder — it doesn’t search down through subfolders unless you tick Include subfolders (below).
Choose where the results go — into a single “Autostack results” folder, or in the same folder as the stack’s source frames.
Confirm the plan — Autostack shows how many stacks it found, how many images they contain, and how many leftover frames didn’t fit a set, plus a disk-space check. Keep the computer awake while stacking sits here too, ticked by default, so a batch you leave running isn’t cut short by your computer nodding off — see Preferences for exactly what it does and doesn’t hold off.
Start it, then carry on working — the batch runs in the background, not in a window you have to sit in front of. Each set is stacked at full resolution with the same unified engine as a manual stack. Batch stacks share the same queue as manual ones, so a stack you kick off yourself mid-batch takes its turn in line rather than competing for the machine.
Check results as they land — progress appears as a chip at the top of the window (Autostacking 3 of 12). Click Show for a per-stack pass/fail log and an Open in Library button, which becomes available as soon as the first result is written — you don’t have to wait for the whole batch to start looking at what’s done. The ✕ on the chip cancels a running batch; the stack already in flight finishes its current checkpoint first.

Options

Output format

Check this before your first run. Three checkboxes decide which files each set produces. Tick any combination — they’re independent, and at least one is required.

JPEG (small, not re-editable) — on by default. Small, fast to write, ideal for spotting keepers, but it can’t be reopened in the Editor for masks, adjustments, or a re-stack.
Developed DNG — a full result you can reopen and edit like any manual stack.
Raw DNG — a genuinely raw file per set, the same Raw DNG the Save dialog writes. It opens correctly in any raw editor — Lightroom, DxO PhotoLab, Capture One, ON1 — and you develop it yourself, so none of Macro Studio’s look or edits are baked into its pixels. Reopened in Macro Studio it’s still your stack, with Retouch available. Files land as Autostack 001 - <settings>-raw.dng.

If you expect to finish any of these images rather than just triage them, tick Developed DNG or Raw DNG up front. Going back for editable versions later means running the whole batch again. Either one reopens as a real Macro Studio document, and either one can be saved again in its own format — so a batch of Raw DNGs is a working starting point, not a dead end.

Raw DNG is greyed out until you turn on Stack RAW photos in camera-raw mode in Preferences — hover it and the tooltip says where.

Some sets can’t run in camera-raw mode: mixed camera models, a JPEG among the frames, Fujifilm bodies, Apple ProRAW. What happens to those depends on what else you ticked. If you asked for a JPEG or a re-editable DNG as well, the set is stacked the normal way and you get those files, just no raw one. If Raw DNG was the only box ticked, there’s nothing left to write — the set is reported in the log as producing no file, with the reason, rather than counted as done.

Scope and mode

Two checkboxes near the top change what the rest of the form does:

Include subfolders (stack each subfolder as one set) — trusts the folders you already made. Every visible folder below the source — at any depth — is taken as one complete bracket and stacked in place, skipping timestamp grouping entirely. Use this when a shoot is already sorted into one folder per subject. Nesting is fine: point it at a season folder holding month folders holding subject folders and every subject folder is found. Each folder contributes only the images sitting directly in it, so a folder that holds both loose images and subfolders gives you a stack of its own images plus one per subfolder.

Two folders can end up with the same name in different places — a stack 1 under each of several shoot folders, say. Because every result lands in the one Autostack results folder, a set found deeper than one level is named after its path from the source folder down: Autostack - june - day 2 - stack 1 - ….jpg.

Autostack skips its own Autostack results and Autostack leftovers folders wherever it meets them, so re-running over a tree you’ve stacked before won’t blend an old leftovers pile as if it were a bracket set. Only folders below the source are skipped — pick one of them as the source folder itself and its images are scanned and grouped by capture time like any other folder.
Only split into stack folders (don’t run the stacks) — groups the loose images into stack 1, stack 2, … subfolders and stops there. No stacks run and no results are written, and existing subfolders are left alone. It greys out the result-location, output-format and include-subfolders controls, which don’t apply.

The two compose into a useful two-pass workflow. Run once with Only split to get the grouping onto disk, check it in your file manager and fix anything the timestamps got wrong — move a stray frame, drop a dud — then run again with Include subfolders and Autostack stacks the folders you just corrected, exactly as you left them.

Source images

Copy into stack folders (originals kept) — the default — or Move into stack folders.

Advanced

Minimum images per stack — sets smaller than this are treated as leftovers rather than stacked. This gates loose images grouped by capture time only: an included subfolder is always taken as one stack whatever this is set to, because you already curated it.
Bracket gap — how long a pause between shots starts a new stack. Increase it if back-to-back brackets are being merged into one. If a single bracket is being split into several stacks, read the note on capture-time precision below before reaching for a smaller gap — a smaller gap is usually the wrong lever, and often the cause. The gap normally steps in half-seconds; once a scan finds your files can’t resolve fractions of a second, it switches to whole seconds and says so under the control (see below).

RAW+JPEG pairs of the same shot are treated as a single frame.

Capture times and the 1-second floor

Autostack groups by the capture time your camera wrote into each file. That time is recorded to the whole second. Some cameras also record the fraction of a second in a second field, and Autostack uses it when it’s there — but plenty of cameras don’t write it at all, and there’s no way to tell from the outside which yours does.

This matters for one setting: a bracket gap under 1 second only works if your files carry fractions of a second. Without them, every shot in a burst lands on a whole second, so the only gaps Autostack can see are 0 seconds and 1 second. A gap of, say, 0.5s then starts a new stack every time the clock ticks over — and one continuous burst arrives as several stacks plus a pile of leftovers, however fast the camera was shooting.

The same applies to a file with no capture time at all — one exported or copied by a tool that dropped the original EXIF. Autostack falls back to the file date for those, which isn’t a capture time and shouldn’t be trusted to a fraction of a second.

You don’t have to work out which case you’re in. Autostack checks, and if your gap is under 1 second and the files can’t support it, the confirm screen warns you in amber and tells you to raise the gap. If you see a single bracket arriving as two or three stacks, that warning is the first thing to look for.

The Bracket gap control follows the same finding. Once a scan has seen that your files carry no fractions of a second, the control stops offering them: it steps in whole seconds, won’t go below 1 second, and a line under it explains why. A gap of 0.5s is raised to 1s, because on those files 0.5s is the setting that splits every burst at each tick of the clock. Half-second steps come straight back if you point Autostack at a folder whose files do carry fractions — the check runs on every scan and follows whichever folder you’re looking at now, so a card that supports fine gaps is never held to another card’s limits.

If Autostack finds nothing

When the confirm screen reports no stacks, it tells you which of these it hit — each has a different fix.

“The images here are inside subfolders…” — the most common one. You picked a parent folder, but the photos are further down. Tick Include subfolders and analyze again, or pick the subfolder itself as the source folder. The check looks all the way down the tree, so it fires for brackets buried several levels deep too, not just one.
“Found images, but none formed a set of N or more shots within Xs…” — the images were found, but capture times didn’t group them the way you expected. Lower Minimum images per stack, widen the Bracket gap, or check that the frames carry the capture times you think they do. Files copied or exported by some tools lose their original EXIF timestamps, in which case Autostack falls back to file dates, which may be spread out or all identical.
“No images found in this folder.” — nothing supported at that level. Check you picked the folder you meant, and that the files are a supported format.
“This folder is no longer available…” — the folder went away mid-scan. This usually means a network share or external drive disconnected or went to sleep; reconnect it and try again.

The confirm screen also shows a leftovers count. Leftovers are images that were found but didn’t land in any set — a high leftover count with zero stacks points at the grouping settings, and zero of both points at the folder you chose.

If one bracket is split across several stacks

Check the Bracket gap first. If it’s under 1 second, that is almost certainly the cause — see Capture times and the 1-second floor above. Set it to 1 second or more and analyze again; the confirm screen warns you in amber when this applies to your files.

If the gap is already 1 second or more, the pause between those shots really was longer than the gap — a flash that couldn’t recycle in time, or a shot you took a beat later. Widen the gap until the bracket holds together, but keep it shorter than the pause between separate subjects.