Focus stacking means taking several photos of a still subject, each focused at a slightly different distance, then merging them into one image that is sharp throughout. It solves the very thin depth of field that macro work produces. Once you learn the routine, it is a reliable way to get crisp insects, flowers and small objects.
Why Macro Needs Stacking
At close distances, the zone of sharp focus can be only a millimeter or two deep, even at small apertures. Closing the aperture a lot adds diffraction, which softens fine detail. Stacking lets you use a moderate aperture and still record the whole subject sharply.
What You Need
- A sturdy tripod, or a stable surface, to keep framing identical.
- A still subject, since movement between frames causes errors.
- A remote release or a timer, to avoid shake.
- Software that can merge stacks, such as common editors or dedicated stacking programs.
Step-by-Step Shooting
- Set up the camera on a tripod and compose the shot.
- Switch to manual focus and manual exposure, so brightness stays the same in every frame.
- Choose a mid-range aperture, often around f/5.6 to f/8, as a first guess.
- Focus on the nearest part of the subject and take the first frame.
- Move the focus a small step farther back and shoot again. Overlap each zone with the last one.
- Continue until the farthest part is sharp. Ten to fifty frames is common, depending on the subject.
- Take one extra frame beyond the end, to be safe.
Some cameras offer a built-in focus bracketing mode that does this automatically. Check your manual for details.
Merging the Frames
Load the files into your stacking software and let it align and blend them. Check the result at full size, looking for ghosting, halos around edges or soft patches. If the output has flaws, try a different blending method or retouch from the source frames.
- Use consistent lighting, since flicker causes brightness shifts.
- Avoid wind, which moves flowers and leaves between shots.
- Clean the lens, because dust spots repeat in every frame.
Tips for Cleaner Stacks
Keep a steady rhythm while you shoot and avoid touching the tripod between frames. If you use a focusing rail, move it in equal small increments so the overlap stays even. Shoot in a sheltered spot, such as indoors or behind a windbreak, because even a slight breeze can ruin a long sequence. Always check the first and last frames to confirm the whole subject is covered.
FAQ
How many frames do I need?
It depends on magnification and aperture. Higher magnification and wider apertures need more frames. Test a short run, check the overlap and adjust.
Can I stack handheld?
Possible for loose compositions, but results are less consistent. A tripod or rail gives far better alignment.
The Short Version
Lock down the camera, use manual settings, shoot overlapping frames from near to far and merge them in software. Keep the subject still and the light steady. All values here are first guesses, so refine them with your own gear.
