15 mm is the best part of this lens. Measured tests put the centre of the frame near the sharpest X-mount lenses ever tested — wide open at f/3.5. Use it confidently for interiors, landscapes, architecture and close-up detail at 13 cm. Just keep faces out of the corners.
23 mm equiv. f/3.5 usable wide open 76° horizontal MFD 13 cm
What it is for
- Interiors and small rooms, where you physically cannot back up.
- Landscapes with a strong foreground — a rock, a path, a gate — because a wide lens exaggerates near-to-far scale.
- Architecture, where corrected distortion is under one percent and genuinely fine.
- Environmental portraits: a person in a place, not a face filling the frame.
- Close-up detail: 13 cm minimum focus and 0.24× magnification make this the close-focus end.
The software half of this lens
Uncorrected, the glass bends straight lines hard at 15 mm — measured at about -6.7% barrel distortion, with up to -2.37 EV of corner darkening wide open. Fujifilm allowed that deliberately in order to make the lens tiny, light and cheap, and ships a correction profile that fixes it.
| Measured at | Distortion, uncorrected | Corrected | Vignetting, uncorrected |
|---|---|---|---|
| 15 mm | -6.70% barrel | -0.62% | -2.37 EV at f/3.5 |
| 28 mm | +1.01% pincushion | -0.09% | -0.87 EV at f/4.5 |
| 45 mm | +2.89% pincushion | -0.53% | -0.80 EV at f/5.6 |
Do not try to switch correction off
You will read advice about disabling lens correction “to get more angle of view”. On Fujifilm X files the correction is effectively not optional, and the uncorrected 15 mm frame has moustache distortion that is harder to fix than the barrel component. The only real cost of correction is slightly softer corners, because corner pixels are stretched — which is part of why the corners never match that spectacular centre.
Two things to watch at 15 mm
- Faces near the edges stretch. Physics, not a fault. Put people in the middle third, or step back and zoom in.
- Keystoning, not distortion, ruins architecture. Tilting the camera up makes a building lean. Keep the sensor plane parallel to the facade, include more foreground than you want, and crop afterwards.
Assignment: one room, four corners
Photograph the same room from each of its four corners at 15 mm, f/5.6, keeping the camera level each time. Then take a fifth frame deliberately tilted up. Compare the leaning walls in that fifth frame with the four level ones. You have just learned the difference between lens distortion and perspective — and only one of them is your fault.