Free focus stacking · in your browser · full resolution

Focus stacking in your browser. Every frame gives its sharpest part.

Drop a focus-bracketed series. Your own computer aligns the frames and merges the sharp regions into one photograph — Mac, Windows, Linux, Chromebook — and the frames never leave it.

Stack a series

Nothing is uploaded. The page has no server to send a frame to.

One frame of a seven-frame focus bracket of a circuit board: the silkscreen and solder pads mid-board are sharp; the header pins in front, the USB socket and the capacitor are soft. The same seven frames stacked by this page: pins, socket, capacitor and the board's silkscreen are all sharp.
Frame 4 of a seven-frame bracket, and all seven stacked by this page at the frames' full size. Drag the handle. Series: Petteri Aimonen, MIT.

Runs in this browser

Stack a focus bracket

Pick every frame of one series shot at successive focus distances. The page aligns them, chooses the sharpest source for every region, and hands back one image at the frames' full size.

      Before you trust the result

      • Inspect it at 100 %. The inspector opens at full size for that reason; a stack that looks right at fit-to-screen can still carry a halo along a fine edge.
      • Moving subjects, wind and a changed exposure between frames produce ghosts the engine cannot remove. Shoot the series in one go.
      • Frames are cropped to the area every frame covers after alignment; a long bracket with a lot of focus breathing loses some edge.
      • There is no retouching brush in this version. If one region is wrong, a desktop stacker with retouching is the right tool for that stack.
      • A RAW bracket is decoded on your processor at about a second per 24-megapixel frame on a recent laptop, twice: a thirty-frame bracket is a minute of decoding before the merge. White balance is the camera's as-shot setting; exposure is set automatically at export (up to +2.6 stops, shown on the check line); the developed look you would make in Lightroom is not applied.

      What happens to your frames

      1. 1 Align

        Focus breathing scales and shifts every frame a little. Each one is fitted to the middle frame on its edges — scale, rotation and shift — so a 7 % drift across a long bracket still lines up.

      2. 2 Vote

        Every frame is broken into six scales of detail. At each scale, every region goes to the frame where it is sharpest, and single-pixel mistakes are outvoted by their neighbours.

      3. 3 Merge

        The winning detail folds back into one image. Two passes keep only the vote, so memory does not grow with the number of frames.

      How it works, in detail · How to shoot a series that will merge

      Questions people ask before they stack

      Is this focus stacking software free?

      Yes. The stacker runs in your browser at full resolution with no account, no watermark and no frame limit other than your computer's memory. The site is paid for by advertising on the pages, never by anything inside the tool.

      Does it work on a Mac, a Chromebook or an iPad?

      Yes — anything that runs a current browser. The stacking happens on your own processor, so there is nothing to install and no Windows-only download. A phone or iPad is limited to ten frames at reduced size because of memory.

      Do my photos get uploaded?

      No. The frames are read by the page in your browser and merged there. The page makes no request that carries a file, a file name or a pixel; a second stack works with the network switched off. The how-it-works page lists every request the page makes.

      Which file types can I stack?

      JPEG, PNG, WebP, AVIF, TIFF (8- or 16-bit, in sRGB, as Lightroom, Capture One, darktable and RawTherapee export it) and RAW straight from the camera — DNG (mosaic; ProRAW and other already-demosaiced DNGs not yet), CR2, CR3, NEF, ARW, RAF, ORF, RW2 and PEF, decoded here in the browser. HEIC decodes in Safari. Frames must all have the same dimensions and one format: a bracket is stacked as RAW or as developed pictures, not both.

      Should I stack the RAW files or the developed JPEGs?

      RAW, when you want the most from the sensor: the frames are merged in linear light with the camera's as-shot white balance and its colour matrix, and the tone curve is applied once, at export, with an automatic exposure. Developed frames, when your look is already made in your RAW software — then stack what you exported, as 16-bit sRGB TIFF for the most precision. Either way the frames never leave this tab.

      How many frames can I stack?

      As many as your memory allows: the engine keeps a few frames' worth of memory whatever the count, and the page tells you before it starts what a stack of your size needs. Fifty 24-megapixel frames are fine on a laptop with 8 GB.

      How is this different from the online focus stacker that uploads my files?

      That service sends every frame to its server and caps the count. This one does the same job on your computer, at full resolution, for as many frames as fit in memory, and the frames never leave the tab.

      Is it as good as Helicon Focus or Zerene Stacker?

      It uses the same family of method as enfuse and Zerene's PMax — align the frames, then choose the sharpest source for every region at every scale. On the example series we test against it matches the open-source reference stacker. It does not yet have a retouching brush, so a stack with a difficult halo may still want a dedicated desktop tool.