How to Focus Stack Jewellery Photography Without the Halos

What Focus Stacking Actually Solves

Focus stacking is the process of shooting a sequence of frames at incrementally different focus points and blending them into one image that is sharp from front to back. In jewellery product photography it exists to solve one specific problem: at macro distances, depth of field collapses to a matter of millimetres, so no single frame can hold a whole ring, from the crown of the stone to the back of the shank, in focus at once.

This isn't primarily an aperture problem, even though it looks like one. Depth of field at macro magnifications is governed mostly by magnification itself, not f-stop. As magnification increases, usable depth of field shrinks roughly with the square of the magnification. A ring reproduced at life size or larger can have a genuinely usable depth of field measured in fractions of a millimetre, no matter how far you stop down.

Why You Can't Just Stop Down to Fix It

The instinctive fix is to close the aperture. It works, up to a point, and then it actively works against you. At macro magnifications, the effective aperture is larger than the number printed on the lens barrel — roughly the marked f-stop multiplied by (1 + magnification). Shoot a 1:1 macro at f/16 and you are, for diffraction purposes, closer to f/32. Past a certain point, diffraction softens every single frame in the stack, which no amount of blending will undo.

In practice, most jewellery product photography sits in the f/8–f/14 range: wide enough to avoid heavy diffraction softening, small enough to keep the number of frames in a stack manageable. Some studios shoot wider still, f/2.8–f/4, deliberately trading a much shallower per-frame depth of field for more frames rather than accepting any diffraction loss at all. Racking all the way to f/16–f/22 "to get more in focus" is the classic beginner mistake — it softens the whole stack instead of extending it.

How Many Frames Does a Ring Actually Need?

There's no fixed number. Frame count is a function of the subject's depth divided by the depth of field each frame captures, with roughly 30% overlap between frames to avoid soft bands where the blend seams sit. As a rough guide:

• A simple ring can sometimes be done with as few as 3–4 frames (stone, crown, mid-band, back of the shank), though high-end work often runs 15–25 frames at a finer step size.
• A pendant follows the same logic but usually needs a couple of frames if shot front on, dpending on the distance between the pendant and the lens
• A bracelet needs smaller more frames if shot from an angle, because the extended focus range across a larger object multiplies the problem.
• A watch typically needs 10–20 frames to cover dial, case and strap depth in one stack.
• A flat, laid-out necklace can need 50 or more frames simply because the focus plane extends across the whole piece, especially if the items fills up the whole frame

The working rule in most studios: a few extra frames beats one missing frame; a gap in the stack shows up as an unrecoverable soft spot in the final blend.

Racking Through Focus: Manual, Motorised Rail, or In-Camera

You can move through the stack three ways. Manual focus racking is the cheapest option but risks inconsistent step sizes and focus breathing between frames, which complicates the eventual blend. A motorised macro rail moves the whole camera in precise, repeatable steps and removes human error, at the cost of setup time. Most current mirrorless and DSLR systems now also offer in-camera focus bracketing: Nikon calls it Focus Shift Shooting, Canon, Sony, Fujifilm, Olympus and Hasselblad call it Focus Bracketing, and Phase One calls it the Focus Stack Tool. These work in image space rather than object space, meaning the camera adjusts step size to hold a consistent circle of confusion regardless of focal length or subject distance — genuinely useful rather than a marketing tick-box. Worth knowing before you buy into a system for jewellery work: some implementations offer finer step-size control than others, and on some camera bodies the electronic shutter required for focus bracketing limits flash sync compatibility, which matters if your studio lighting is strobe-based.

Choosing Stacking Software

The blend engine matters as much as the capture technique, and jewellery is a harder test case than most focus-stacking subjects because of the high-contrast edges around facets and prongs.

• Zerene Stacker offers two blending methods. PMax is fast and automatic but prone to haloing on exactly the high-contrast edges a faceted stone or a prong setting produces. DMap needs a manual contrast-threshold input but handles contrasty jewellery images noticeably better, and its retouching brush lets you paint in sharp pixels from a specific source frame where the blend gets it wrong. It doesn't support RAW files directly, which is a real limitation for colour-critical jewellery work.
• Helicon Focus processes faster, supports RAW natively, and its retouching tool is generally quicker to work with than Photoshop's for painting in sharpness from source layers.
• Photoshop (Auto-Align + Auto-Blend Layers) is free if you already own it, but is slower, more prone to visible ghosting or blur that needs manual layer masking to fix, and becomes genuinely impractical past roughly 20 frames — a ceiling many jewellery stacks exceed.

The Rule That Breaks Stacks If You Ignore It: Lighting Must be consistent.

Every frame in a stack has to match exactly in exposure and white balance, or the blending software misreads where one sharp region ends and the next begins. Shoot in full manual exposure — Aperture Priority will drift exposure frame to frame and introduce visible banding in the final blend. Continuous LED lighting lets you preview focus live but needs a locked, manual white balance and genuinely stable, non-flickering output. Flash gives more consistent per-frame output and shorter exposures, which reduces vibration risk, but only if power and recycle time are identical on every single frame. Get this wrong and you'll see ghosting, colour shifts between blended zones, and hard blend-line errors, worst of all on reflective metal and gemstone facets — which links directly to how you're lighting the piece in the first place.

Fixing the Artifacts That Are Specific to Jewellery

Two problems come up disproportionately often on jewellery stacks. Haloing around stone facets and prongs happens because high local contrast confuses the blending algorithm, worst with PMax or Auto-Blend; the fix is DMap threshold tuning or a manual retouch pass. Moving specular highlights — a bright point on polished metal that shifts position slightly between focus positions — don't align cleanly and usually need a manual masking pass, or tighter lighting control to minimise how much a highlight moves as focus shifts. Vibration is a simpler fix: a two-second timer or cable release, and the piece secured rigidly with wax, putty or a proper jewellery clamp rather than balanced against a prop. Always review the merged stack at 100% before calling it finished — soft bands and blend seams are far easier to catch and refix at that point than after the file has gone into a listing.

What This Actually Costs in Studio Time

5–10 frames adds relatively little to a shoot, whereas 20–50 frames per product can add a few minutes per shot once both capture and stacking are factored in. Stacking itself varies hugely by software, from seconds in Helicon for a modest stack up to 15–30 minutes in Zerene, before any manual artifact cleanup. It can be slow, deliberate work, which is why so many photographers skip it and end up with a hero shot that looks soft the moment a customer zooms in.

Further Reading

For the underlying optics, Cambridge in Colour's depth of field tutorial is a solid technical primer, and Lensrentals' breakdown of how in-camera focus bracketing actually works is worth reading before you buy a body specifically for this feature.