What Is a RAF File? Fujifilm RAW and X-Trans Explained
A .RAF file is Fujifilm RAW — sensor data plus settings from an X-series or GFX camera.
Unlike most RAW formats, the interesting part of a RAF is not the container. It is that many Fujifilm cameras use a colour filter array that almost nothing else uses, which means the software reading the file has to do something genuinely different with it. That single fact explains most of what people notice about Fujifilm files.
X-Trans, and why it complicates things
Almost every digital camera places colour filters over its sensor in a Bayer pattern: a repeating 2×2 tile of red, two greens and blue. Decades of research have gone into reconstructing a full-colour image from it, and every RAW converter is very good at it.
Fujifilm's X-Trans sensors use a 6×6 tile instead, with a less regular arrangement of the same three colours. The intent was to break up the repetition that causes moiré, allowing Fujifilm to omit the optical low-pass filter and gain a little sharpness.
The consequence is that standard demosaicing algorithms do not apply. Every converter has to implement X-Trans handling separately, and they differ in quality. This is the origin of the long-running complaint about 'watercolour' or 'wormy' rendering of fine detail — foliage especially — in some software: it is a demosaicing artefact, not something wrong with the file.
Not every Fujifilm camera is X-Trans. The GFX medium-format line uses conventional Bayer sensors, as do some entry-level X bodies, and those files behave like any other RAW.
Which software handles RAF well
This matters more for Fujifilm than for other brands, and it is worth testing rather than assuming. Capture One has long been regarded as strong on X-Trans. Iridient Developer built its reputation on it. RawTherapee and darktable both offer X-Trans-specific demosaic algorithms you can choose explicitly.
Adobe's handling has improved substantially over the years and its Enhance Details feature was aimed squarely at this problem. The old criticism is less true than it was, but the fact that it needed a dedicated feature tells you the underlying difficulty is real.
If fine natural detail in a RAF looks smeared or oddly textured, trying a second converter on the same file is a genuinely useful diagnostic — and one that would tell you nothing on a Bayer file.
Film simulations live in the file
Fujifilm's film simulations — Provia, Velvia, Classic Chrome, Acros and the rest — are a large part of why people shoot the brand, and a RAF records which one was active as metadata rather than baking it in.
Fujifilm's own software and a few third-party converters apply it. Others do not, which is why a RAF can open looking noticeably plainer than the camera's screen showed. The embedded JPEG preview has the simulation applied; the RAW data does not.
This is also why in-camera RAW conversion remains genuinely useful on Fujifilm bodies in a way it is not elsewhere: reprocessing a RAF in-camera gives you the manufacturer's own rendering of a simulation, which no external converter reproduces exactly.
Compression and file size
Recent bodies offer uncompressed, lossless compressed and lossy compressed RAF. As with every manufacturer, lossless compressed is the default worth using — smaller than uncompressed with no cost.
RAF files from higher-resolution bodies are large, and the GFX line larger still. Nothing about the format is unusual here; the sensors are simply big.
Frequently asked questions
Why does fine detail in my RAF look smeared?
Almost certainly X-Trans demosaicing rather than the file. Foliage, hair and fine texture are where the difference between converters shows most. Opening the same file in a second converter — Capture One, Iridient, or RawTherapee with an X-Trans-specific algorithm — will tell you in a minute whether that is the cause.
Do film simulations survive into Lightroom?
The setting is recorded in the file, but Lightroom does not apply Fujifilm's rendering of it by default. Adobe ships camera-matching profiles named after the simulations which get close. For the manufacturer's exact rendering, reprocess the RAF in-camera or use Fujifilm's own software.
Are all Fujifilm cameras X-Trans?
No. The GFX medium-format line uses conventional Bayer sensors, and some entry-level X-series bodies do too. Those files demosaic like any other RAW and none of the X-Trans considerations apply.
Should I convert RAF to DNG?
It is an option for compatibility, and Adobe's free converter handles X-Trans files. Be aware that the DNG still contains X-Trans mosaic data, so it does not sidestep the demosaicing question — it only changes which software can open the file.
What is a .RAF file's relationship to the JPEG my camera also wrote?
The JPEG is Fujifilm's own rendering of the same capture, with the film simulation, sharpening and noise reduction applied. The RAF is the data before any of that. On Fujifilm in particular the JPEG is genuinely good enough that many photographers keep both deliberately.
Drop a RAF into RawCut's metadata reader to see the film simulation, sensor details and full EXIF — in your browser, nothing uploaded.
Read a RAF's metadata