How to Use the MCEX-18G WR Macro Extension Ring
By Fujifilm House of Photography | Published: 2026-10-16
Category: How-to Guides
A step-by-step guide to fitting and shooting with the MCEX-18G WR on GF lenses, including focus-distance shifts, exposure checkpoints, and the mistakes that cost you sharpness.
Quick answer
Fit the MCEX-18G WR between a GF lens and the GFX body, then expect the usable focus range to move much closer and the far end to fall away. Set the lens to manual focus, focus by moving the camera rather than turning the ring, and stop down to regain depth of field. The 18mm tube is the gentler of the two GF options, so it suits flowers, products, and detail shots where you still want some working distance.
What the 18mm tube actually changes on a GF lens
A macro extension ring is an empty spacer: it adds distance between the lens and the sensor, which shortens the minimum focus distance and raises magnification. That is the whole mechanism, and it explains the side effect people notice first. Because the lens is now optimised for close work, it may no longer reach infinity at all, and the focus ring's travel covers a much narrower band of real distances.
Magnification and focus distance shift differently for every GF lens, so treat any figure you read as lens-specific rather than universal. Fujifilm publishes magnification and focus distance information for the extension rings, and that table is the fastest way to know whether the 18mm tube or the longer 45mm tube gets you to the framing you want.
- Shorter tube: less magnification gain, more working distance, easier lighting.
- Longer tube: more magnification, tighter working distance, harder lighting.
- Either tube: infinity focus may be lost while the ring is fitted.
Match the ring to the body you are shooting
The WR in the name means the ring is weather-resistant, which matters most when the camera behind it is too. On a GFX100S II the combination stays sealed against dust and light moisture, so a damp garden or a windy outdoor product shoot is less of a gamble. The ring also carries the G mount's electronic contacts, so the body still knows which lens is attached and normal metering continues.
If you are weighing up a dedicated macro lens against a tube, be honest about frequency. A tube is the cheaper way to test whether close-up work suits you, and it reuses glass you already own. A macro lens is the better answer if close focusing is going to be a regular part of your work rather than an occasional experiment.
Lighting and stability at close range
At high magnification, the depth of field you have left is measured in millimetres, so light and support stop being optional. Diffused light from slightly above and in front of the subject reads better than a bare on-camera flash, which tends to leave a hard shadow directly behind whatever you are photographing. A small diffuser or a sheet of tracing paper held off to one side is often enough.
Support matters just as much. A tripod removes the slow drift that ruins stacked or repeated frames, and if you are hand-holding, brace your elbows and shoot in short bursts so one frame lands cleanly. Wind, a wobbling table, and even your own breathing all show up at this scale.
Step-by-step: fitting and shooting the MCEX-18G WR
- Power the body off before you mount anything: Switch the GFX body off, remove the lens, and fit the MCEX-18G WR to the body first, then attach the lens to the ring. Line up the mount index marks and turn until it clicks rather than forcing it. Mistake to avoid: mounting the ring to the lens first and then wrestling the whole assembly onto the body, which is where bent contacts happen.
- Switch the lens to manual focus: Autofocus hunts badly once the focus range has collapsed to a narrow band. Set the focus mode to manual so you keep control of where the plane of focus sits. Checkpoint: if the lens refuses to focus at all, you are probably outside the new working range, not dealing with a fault.
- Find the new working distance before composing: Move the camera slowly toward the subject until the image snaps into focus, then note roughly how far away you are. That distance is your working range for the rest of the shoot. Mistake to avoid: turning the focus ring to its limit and assuming the lens is broken when nothing sharpens.
- Focus by moving the camera, not the ring: At this magnification the focus ring covers very little real distance, so small camera movements are the practical way to place focus. A focusing rail or a tripod head with fine adjustment makes this repeatable. Checkpoint: if you are chasing focus back and forth, lock the tripod and shift the whole camera instead.
- Stop down and check depth of field: Apertures around f/8 to f/11 usually give a workable balance between depth of field and diffraction at close range. Review at 100 percent on the rear screen rather than judging from the thumbnail. Mistake to avoid: shooting wide open, where a single petal or product edge is sharp and everything else dissolves.
- Diffuse the light before adding more of it: Move a diffused source above and slightly in front of the subject, and use a reflector or white card on the shadow side. More bare light usually makes close-up images worse, not better. Checkpoint: if shadows have hard edges, soften the source before raising its power.
- Remove the ring when you are finished: Take the lens off, then the ring, and refit the body and lens caps. Store the ring with its caps on so the contacts and threads stay clean. Next step: refit the lens directly to the body and confirm normal focusing has returned before your next shoot.
Gear facts worth knowing
- MCEX-18G WR G Mount 18mm Macro Extension Ring: Connecting the macro extension tubes to any GF lens allows macro photographs to be taken at a higher magnification ratio, and the photographer can choose the 18mm MCEX-18G or the 45mm MCEX-45G depending on the magnification ratio required. The two tubes are a choice, not a set you must own. Pick the 18mm when you want a modest magnification bump with usable working distance, and step up to the 45mm only when you need to get closer still.
- Fujifilm GFX100S II: The FUJIFILM GFX100S II is described as offering an immersive large format photography experience that captures favourite places in breathtaking detail. The high-resolution sensor is what makes a tube worth carrying: fine texture and small subjects hold up when you crop or print large, so the magnification gain translates into visible detail rather than empty pixels.
- FUJINON GF 20-35mm F4 R WR: The GF20-35mmF4 R WR is an ultra wide-angle zoom in a compact, light, and weather-resistant design. A weather-resistant zoom paired with a weather-resistant ring keeps a sealed chain from lens to body, and the wide focal range lets you include background context in close-up frames instead of isolating every subject.
