How to plan a focus stack

Take several frames focused at different distances and combine the sharp parts. The trick is leaving no gaps.

When depth of field cannot cover the subject at any usable aperture — routine in macro work — the answer is several frames at different focus distances, merged.

Step-by-step

1. Enter your lens, aperture and sensor.
2. Enter the near and far distance to cover.
3. Read the focus positions and frame count.

Overlap the slices deliberately

Each frame contributes a slab of sharpness. If consecutive slabs merely touch, any small error leaves a soft band running through the finished image — and it cannot be fixed without reshooting.

Plan for the slabs to overlap by roughly 20–30%. More frames is cheap insurance; a gap is fatal.

Do not stop down to reduce the frame count

Tempting and counterproductive. Small apertures increase depth of field but introduce diffraction, which softens the whole frame. Past roughly f/8 to f/11 on most sensors — and much earlier at macro magnifications, where the effective aperture is far smaller than the marked one — you lose more to diffraction than you gain in depth.

Stack more frames at a sharper aperture instead.

Two ways to move focus

Turn the focus ring. Fine for landscapes. In macro it changes magnification slightly between frames, which the software must correct.

Move the camera on a focusing rail. The standard macro approach: magnification stays constant and the software's job is much easier.

Frequently asked questions

How many frames do I need?

It depends on the depth each frame covers and the range to span. The planner works it out — expect a handful for a landscape and dozens for high-magnification macro.

Should I stop down to need fewer frames?

No. Diffraction softens the entire image at small apertures, and at macro magnifications it sets in much earlier than the marked f-number suggests. Shoot at a sharp aperture and take more frames.

Why is there a soft band across my finished stack?

A gap between two frames' zones of sharpness. Plan for 20–30% overlap between slices rather than letting them just touch.