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SPECIFICTION
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focus-stack

github.com

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Spec score 8.3 #6 of 24 in Focus Stacking Software

What it is

focus-stack is a free desktop program that combines photographs taken at different focus settings into an image with extended depth of field. For each pixel, it selects the sharpest source image, a method documented for uses such as microscope photography. The tool can resize and rotate stack images to align them, or alignment can be skipped or adjusted. Outputs include a focus-stacked image, an optional depth map, and a 3D preview based on that map. Input formats supported by OpenCV include JPG, PNG, and TIFF, while the filename extension determines output format. Processing controls cover denoising, consistency filtering, batch size, and thread count. OpenCV’s OpenCL interface provides GPU acceleration when available, with an option to disable it. Binary packages are listed for Windows 10, Ubuntu 20.04, and Mac OS X. The project is MIT licensed; Linux builds require OpenCV 3.0 or newer and basic build tools.

Spec sheet

Purpose
Combines photos taken at different focus settings by selecting the sharpest source image for each pixel to create an extended depth of field image.Read 9 Oct 2026 · github.com
License
The repository identifies the project as MIT licensed.Read 9 Oct 2026 · github.com
Acceleration
OpenCL GPU acceleration is used when available and can be disabled with an option.Read 9 Oct 2026 · github.com
Android
The README mentions a third-party Android app that uses focus-stack's algorithm.Read 8 Oct 2026 · github.com
Android connection
The README links to a third-party Android app that uses focus-stack as its algorithm.Read 9 Oct 2026 · github.com
Build dependency
The Linux build instructions specify OpenCV 3.0 or newer and basic build tools.Read 8 Oct 2026 · github.com
Depth outputs
Optional outputs include a depth map and a 3D preview generated from the depth map.Read 9 Oct 2026 · github.com
Desktop downloads
The README says binary packages are available for Windows 10, Ubuntu 20.04 and Mac OS X.Read 9 Oct 2026 · github.com
Downloads
The README lists binary packages for Windows 10, Ubuntu 20.04, and Mac OS X on the GitHub releases page.Read 8 Oct 2026 · github.com
File formats
The README says input can use formats supported by OpenCV, including JPG, PNG, and TIFF.Read 8 Oct 2026 · github.com
GPU acceleration
The tool uses OpenCV's OpenCL interface for GPU acceleration when available, and provides an option to disable it.Read 8 Oct 2026 · github.com
Image alignment
It can resize and rotate images to align them, and can compensate for white balance and exposure differences.Read 9 Oct 2026 · github.com
Input and output formats
Inputs can use formats supported by OpenCV, including JPG, PNG and TIFF, and output format is selected by file extension.Read 9 Oct 2026 · github.com
macOS caveat
The README says the macOS application is unsigned and may be quarantined by the operating system.Read 9 Oct 2026 · github.com
Memory requirement
The README estimates about 100 MB of RAM per megapixel at default settings and about 50 MB per megapixel with one thread and batch size two.Read 9 Oct 2026 · github.com
Memory use
The README estimates about 100 MB of RAM per megapixel by default and about 50 MB per megapixel with --threads=1 and --batchsize=2.Read 8 Oct 2026 · github.com
Output options
It can generate a focus-stacked image, a depth map, and a 3D preview image.Read 8 Oct 2026 · github.com
Processing controls
Options include image alignment, denoising, consistency filtering, batch size, and thread count.Read 8 Oct 2026 · github.com
Release
The releases page lists Version 1.5 and a separate prerelease named latest.Read 8 Oct 2026 · github.com
Typical use
The manual describes microscope photography as a typical use, where depth of field may not cover the whole subject.Read 9 Oct 2026 · github.com

Plans and prices

focus-stack Free No pricing or usage limits stated Read 9 Oct 2026 · github.com

Every focus-stack plan and price →

Strong points and limits

Strong points

  • Free with no stated usage limits
  • Automatic image alignment options
  • Produces depth maps and 3D previews
  • Supports JPG, PNG, and TIFF inputs
  • OpenCL GPU acceleration when available

Limits

  • Default memory estimate is about 100 MB per megapixel
  • Linux builds require OpenCV 3.0 or newer
  • macOS application is unsigned and may be quarantined
  • No free trial is offered

Who it suits

It suits photographers, including microscope photographers, who need more depth of field from a focus series. It is intended for desktop systems running Linux, macOS, or Windows.

Verdict

focus-stack provides focused stacking, alignment controls, depth outputs, and optional GPU acceleration at no listed cost. Users should review its memory estimates and platform-specific setup notes before processing large stacks.

Where Specifiction places it

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