A focus stacking calculator tells you exactly how many exposures to take so that every part of your subject is sharp after merging in software. Enter your camera sensor, lens settings, and subject distance to get the precise shot count, step distance between frames, and total achievable depth of field.
Shot Parameters
Results
Enter your settings and click Calculate
How to Use the Focus Stacking Shot Calculator
Focus stacking overcomes the fundamental depth of field limitation of macro photography. At 1:1 magnification, the total DoF can be less than 1mm — far too thin to show an insect's eye and antennae both in focus. By taking a sequence of shots and shifting focus slightly between each one, then blending in software, you can achieve seemingly impossible depth of field while keeping diffraction to a minimum.
Step 1: Set Your Camera Parameters
Select your camera sensor (determines the circle of confusion value used in the DoF formula), your lens focal length, and the aperture you plan to use. For macro focus stacking, f/5.6 to f/8 is typically the sharpest range on APS-C and full-frame sensors. Above f/11, diffraction begins to soften the image more than the extra DoF helps.
Step 2: Enter Subject Distance and Focus Range
Subject distance is the distance from your camera sensor to the subject. For close-up macro work this might be 6 inches or 15 cm. Focus range is how much depth you want to cover — for a small beetle that is 5mm deep, enter 5mm. Toggle between imperial and metric with the switch in the top right of the input panel.
Step 3: Choose Your Overlap
The overlap slider controls how much adjacent frames share their in-focus zones. 60% is the standard recommendation — it gives stacking software enough redundancy to blend without artifacts. Use 70–80% for challenging subjects with fine detail or when shooting in slightly windy conditions. 40–50% is only appropriate for controlled studio macro work.
Step 4: Read the Results and Shoot
The calculator tells you the exact number of shots and the distance to shift focus between each frame. Use a focusing rail (manual or motorized) to move the camera by the step distance between frames — this is more reliable than turning the focus ring, which changes magnification. Keep your subject and camera completely still throughout the sequence.
Merging in Software
Import your stacked sequence into Photoshop, Helicon Focus, or Zerene Stacker. In Photoshop, load files as layers, select all layers, then use Edit > Auto-Blend Layers > Stack Images. For best results, shoot tethered or use a motorized rail so each frame is perfectly aligned.
Frequently Asked Questions
Is this focus stacking calculator free?
Yes, completely free with no signup required. All calculations run in your browser. No data is transmitted anywhere.
Is my data private when using this tool?
Absolutely. Everything runs locally in your browser using JavaScript. No settings or calculations are stored or transmitted.
What is focus stacking?
Focus stacking is a technique where you take multiple photos at the same composition but shift focus slightly between each frame. Software then merges the sharpest parts of each image into a single photo with much greater depth of field than any single shot could achieve — especially useful in macro photography.
What circle of confusion value should I use?
Circle of confusion depends on your sensor size and how you plan to view the final image. Common values: full-frame = 0.03mm, APS-C = 0.02mm, Micro 4/3 = 0.015mm. These are the standard values used by most depth of field calculators and produce good results for typical viewing distances.
Why does aperture matter for focus stacking?
Smaller apertures (higher f-numbers) give more DoF per frame, meaning fewer shots are needed. However, above f/11 on full-frame and f/8 on APS-C, diffraction softens the image more than the extra DoF helps. For macro focus stacking, f/5.6–f/8 is usually the sweet spot.
What overlap percentage should I use between shots?
60–70% overlap is recommended for most focus stacking workflows. Higher overlap means more shots but gives software more data to blend seamlessly. 50% overlap is the minimum — stacking software can struggle with gaps below this. For critical macro work with bright backgrounds, use 70% overlap.
What software can I use to merge focus stacked images?
Popular options include Adobe Photoshop (Edit > Auto-Blend Layers > Stack Images), Helicon Focus (dedicated focus stacking software), and Zerene Stacker. All three produce excellent results. Lightroom does not natively stack focus — you need to export to another application.