What Is a RAF File? Fujifilm Raw, and the Sensor That Makes It Different
A RAF holds what your Fujifilm sensor measured. Jump to your question below, or work through it in order.
A RAF holds what your Fujifilm sensor measured. Jump to your question below, or work through it in order.
A RAF file is a raw photo from a Fujifilm camera. Inside are the readings your sensor took, kept as readings rather than developed into a picture, with the full JPEG preview and every setting you shot alongside them.
Most RAF files come off an X-Trans sensor, which lays its color filters out differently from every other maker. That one difference explains nearly everything people find odd about this format.
Free software opens a RAF. Fujifilm gives you two converters, and a Mac reads RAF files with nothing installed.
When a Fujifilm digital camera shoots raw, it writes down what every photosite captured and stops there. No white balance baked in, no sharpening, no color decisions. That record is your RAF, and the name stands for nothing cleverer than Fujifilm raw.
A JPEG rides along inside every RAF, full size, made by the camera with your film simulation applied. That preview is what your camera screen shows after the shot, and what your file manager draws in a folder. Raw numbers underneath look nothing like it yet.
RAF files are big. A recent body writes 30 to 60 MB per frame depending on your compression setting, against three or four for a JPEG of the same picture.
Fujifilm sits apart from the raw world twice over. Its sensors use a 6 by 6 color mosaic rather than the usual 2 by 2. Its RAF files are not built on TIFF, the way NEF, ARW, CR2 and DNG all are.
.raf, sometimes written .RAFFUJIFILMCCD-RAW, sixteen bytes of plain textfmt/642, with no byte signature recordedWrong maker? Nikon NEF files, Sony ARW files and Canon CR2 files are the same idea from the other three big makers, and all three are built on TIFF.
Nearly every camera sensor ever made uses a 2 by 2 color mosaic. Fujifilm uses a 6 by 6 one. Every other oddity on this page follows from that.
Sensors measure brightness and nothing else. Color comes from a grid of tiny filters laid over them, a color filter array. Almost everybody uses the Bayer layout: red, green, blue and a second green, repeating in blocks of four.
Fujifilm announced X-Trans on 9 January 2012 with the X-Pro1. Wikipedia describes it as a unique 6 by 6 pattern of photosites with an irregular arrangement, and the irregularity is the point.
Point a regular grid of filters at a regular pattern in the world, a shirt weave or a roof tile, and you get moire. The usual cure is the low-pass filter: one blur layer over the sensor, softening the picture slightly so interference never forms.
Fujifilm built X-Trans to break that interference up with the mosaic itself. An irregular block scatters the pattern, so the blur layer comes off and your sensor keeps detail it would otherwise have lost.
No blur layer. More detail from the same pixel count.
Everything must be rewritten. Code for Bayer does not work here.
Turning either mosaic into a full-color photo means working out the two missing colors at every pixel from its neighbors. For Bayer, that job has been solved and re-solved since the 1970s. For a 6 by 6 irregular grid, every converter had to start again, and section 6 is what happened when one of them got it wrong.
There have been five generations. X-Trans in 2012, X-Trans II in 2013, III in 2016, 4 with backside illumination in September 2018, and 5 HS and 5 HR between May and September 2022. Software has to be taught every one of them separately.
Want that step itself explained? The Nikon NEF file format covers how a camera turns one measured color per pixel into three, and why no two converters agree. Same arithmetic here. Only the mosaic changed.
Not every Fujifilm camera has an X-Trans sensor. The cheaper bodies use ordinary Bayer, and they write files ending .raf too.
Advice about RAF files almost always assumes X-Trans, and for a good share of Fujifilm owners that assumption is wrong. The extension names the maker. It says nothing about the mosaic.
| Camera line | Sensor | Notes |
|---|---|---|
| X-Pro, X-T, X-H, X-S, X-E | X-Trans | The bodies people mean by Fujifilm raw |
| X100 series, from X100S on | X-Trans | The original 2011 X100 came before it |
| X-A1 to X-A20 | Bayer | The entry level line, 2013 to 2018 |
| X-T100, X-T200, X-A5 | Bayer | 24 megapixel, shared across the three |
| XF10 | Bayer | 2018 compact, same sensor as the X-A5 |
| GFX medium format | Bayer | The largest sensors Fujifilm makes are not X-Trans |
| FinePix EXR compacts | EXR | Older still, from before March 2011 and the first X100 |
The GFX row is the one that surprises people. Fujifilm's most expensive cameras use a conventional mosaic, because at medium format resolution moire stops being the problem X-Trans was built to solve.
Three sensor designs, one suffix. A RAF could hold that irregular 6 by 6 mosaic, an ordinary Bayer grid or an older EXR layout, and nothing in its name separates them. Converters work it out from the camera model instead, which is why raw support arrives body by body rather than format by format.
Your file knows which camera it came from, and you can read it without a converter. The camera model sits in plain text 28 bytes into every RAF. Section 10 shows you where to look.
Nobody needs to buy software to see what they shot. The two Fujifilm converters cost nothing, macOS handles RAF files unaided, and Windows needs one free download.
Viewing a RAF and developing it are different jobs. Viewing needs software that reads the JPEG preview inside. Developing means working from sensor numbers, which needs a converter that knows your particular camera.
| Software | Runs on | Why choose it |
|---|---|---|
| Fujifilm X RAW STUDIO | Windows, Mac | Fujifilm color exactly. It borrows your camera to do the work |
| RAW FILE CONVERTER EX | Windows, Mac | Fujifilm bundles it, built by Ichikawa Soft Laboratory |
| Apple Preview and Photos | Mac | Already there. Double-click and it opens |
| Microsoft Photos | Windows | Add the free Raw Image Extension from the Store first |
| darktable | Windows, Mac, Linux | A full raw editor with X-Trans handling built in |
| RawTherapee | Windows, Mac, Linux | Several X-Trans demosaic methods to choose between |
| Adobe Lightroom | Windows, Mac | Paid. The one most owners already have open |
| Capture One | Windows, Mac | Paid, and the name Fujifilm shooters bring up most |
| Corel PaintShop Pro | Windows | Paid, and it opens RAF files alongside ordinary photos |
Open your RAF on a Mac, or add the Raw Image Extension on Windows.
X RAW STUDIO. Every other converter is only guessing at it.
Any text editor tells you something useful too. Open a RAF in Notepad and the first line reads FUJIFILMCCD-RAW followed by your camera model, in plain letters. That is enough to prove the file arrived intact and to settle which body shot it.
Is the computer at fault rather than the photo? Our Windows error guides and macOS fixes deal with the associations that decide what a double-click opens.
Whatever converter you are pointing at the file predates the body that shot it. That is the answer in most cases, and nobody expects it, because your RAF looks perfectly normal.
Raw files are not one format that every camera shares. Every new body records its sensor slightly differently, so converters ship support camera by camera. A RAF from a body released after your software was built stays unreadable until that software catches up.
Three of those four are about software and only the last is about your photo. Before blaming the RAF, open it in a text editor and look at line one. Readable text there means the bytes arrived.
Do not let software “repair” a RAF. Nothing can rebuild sensor data that never finished copying, and products advertising raw repair are selling you a viewer under another name. Copy the RAF again from the card instead, which almost always works.
For about a year, the most widely used raw converter in the world turned Fujifilm foliage into watercolor. That is why Fujifilm owners still argue about software.
X-Trans arrived in January 2012 and every converter had to write new code before it could read a RAF. Adobe shipped support quickly, in ACR 7.3, and it was visibly poor. DPReview tested it in February 2013 and put the problem plainly.
"the foliage takes on a distinct 'watercolor' appearance"DPReview, Adobe's Fujifilm X-Trans sensor processing tested, 25 February 2013
The same test found green bleeding into the white text of a sign, and unnatural edge artifacts in fine detail textures. Capture One Pro 7 gave more crisp results than ACR on the same files, and Iridient Developer built a reputation on handling X-Trans properly.
Adobe rewrote its X-Trans path in Camera Raw 7.4, released that same month. DPReview called it a much-anticipated re-working of raw support for Fujifilm X-Trans sensor cameras. The watercolor effect went. The new output was marginally softer and wanted more sharpening, which is a trade most people took happily.
That was more than a decade ago and it is long fixed. What it left behind is a habit. Fujifilm owners compare converters more carefully than anybody else, and the advice to keep RAF files out of Lightroom is still repeated by people who never retested it.
Any current converter is fine. The 2013 problem is history.
Check its date. Most X-Trans warnings predate Camera Raw 7.4.
RAF files surprise people a second time, and again it is the preview. Your camera applies a film simulation, Velvia or Classic Chrome or Acros, and bakes it into the JPEG inside. You have been looking at that rendering all along, on the back of the camera and in every thumbnail since.
A converter working from the raw numbers starts without any of it. That photo you liked on the back of your camera is still reachable: Fujifilm records which simulation you used, and most converters ship matching profiles. It is a setting you select, though, rather than where the RAF opens.
X RAW STUDIO sidesteps all of it. It hands the file back to your camera and lets the camera render it, so the result is what the camera would have produced. Section 8 covers how that works.
NEF, ARW, CR2 and DNG are all TIFF files from the first byte. A RAF is not. It has its own header, and the TIFF turns up inside as one block of three.
Every other raw format on this site borrowed TIFF as a container and hung its data off tag directories, starting at byte zero. Fujifilm went its own way. A RAF opens with 60 bytes of fixed header, and the first sixteen spell out what it is in letters you can read.
| Offset | Length | What is there |
|---|---|---|
0 | 16 bytes | FUJIFILMCCD-RAW, plain text |
16 | 4 bytes | 0201, fixed |
20 | 8 bytes | FF389501, fixed |
28 | 32 bytes | Your camera model, in plain text |
60 | onward | The offset directory, which points at everything else |
The offset directory holds a version number, then pairs of numbers giving where every block starts and how long it runs. Blocks can sit anywhere in the RAF, because the directory says where to look.
0x131, which records the color mosaic.Numbers in a RAF are stored big endian, which Fujifilm's own notes call Motorola order. Most formats you meet on a PC run the other way round, which is one more reason general-purpose tools need specific code here.
None of this came from Fujifilm. No RAF specification was ever published. Everything above was worked out by the libopenraw project from the files themselves, and libopenraw is also the only source the national format registry cites. Section 10 covers what that means in practice.
Four routes out, and one of them is unusual: Fujifilm will send the file back to your camera and let the camera do the work.
A RAF is a starting point, not the finished picture. Converting one comes down to two questions: what you want at the other end, and who you want making the color decisions.
| You need to | Convert to | How |
|---|---|---|
| Share it or print it | JPEG | X RAW STUDIO for camera color, or any converter for your own |
| Archive it | DNG, and keep the RAF | Adobe DNG Converter, free. The trip is one way |
| Edit it in layers | TIFF or PSD | Develop first, then export 16-bit from your converter |
| Open it on a phone | JPEG | Convert on the computer. Phone apps rarely read X-Trans |
| Keep every option open | Nothing | Leave the RAF alone. Converters keep improving |
X RAW STUDIO is free, and it works in a way no other maker copies. You plug the camera in over USB, and as DPReview puts it, X Raw Studio uses the image processor inside your camera to process Raw files. Your computer is only driving the screen.
The result is not a guess at Fujifilm color. It is Fujifilm color, because the camera did the work, on the same chip that would have rendered the JPEG in the first place. Every film simulation and every setting is still there to change afterwards.
X RAW STUDIO. Nothing else gets closer, because nothing else is the camera.
Use a raw editor. X RAW STUDIO processes files, it does not organize them.
Converting to DNG does not get you back to RAF. Plenty of owners archive as DNG anyway, and it is a reasonable choice. The DNG file format works through that decision properly before you commit an archive to it.
Three settings in the camera menu, and one right answer for nearly everybody: lossless compressed. It halves the file and keeps every number.
Recent Fujifilm bodies record a RAF three ways. The names sound similar, and the difference between two of them matters.
| Setting | Size | What happens |
|---|---|---|
| Uncompressed | 57.4 MB | Every number written out in full |
| Lossless compressed | 27.6 MB | About half the size, and identical image data |
| Compressed | 26.4 MB | Throws image data away to save a little more |
Lossless compressed takes roughly 52 percent off the uncompressed size with nothing discarded, the way a zip file shrinks a document. Plain compressed saves barely more and does reduce color information, so it is the one setting worth avoiding unless your card is full.
Older bodies offer fewer choices. Compression came in around the X-Pro2 and X-T3, lossy compressed arrived with the X-T4, and models before that often record uncompressed only. If your menu has two options rather than three, take the compressed one and stop worrying.
Comparing makers? The Sony ARW file format offers the same three-way choice under different names, and its trap is that the default setting is the one that discards data.
A RAF announces itself in sixteen bytes of plain text. Your computer still may not recognize one, and the reason is worth a minute.
Extensions get lost. A RAF comes off the card named DSCF0001 with nothing after the dot, or a download strips the suffix. You need no converter to find out what you are holding.
FUJIFILMCCD-RAW means a Fujifilm raw file, and your camera model follows a few characters later.That camera model is the useful part. It names the body that shot your RAF, which settles whether the sensor was X-Trans, which settles what your converter has to support. Converters list the camera models they read.
PRONOM is the registry archivists check files against. Its RAF record is fmt/642, Fujifilm RAW Image Format, classified as Image (Raster), and it lists no developer, no release date and no byte signature.
That last one is the odd part. Byte signatures are exactly what PRONOM exists to hold, and a RAF opens with sixteen fixed bytes of ASCII. The entry names one contributor, Artefactual Systems, and cites one source: notes published by libopenraw, a volunteer project that worked the format out. It was last updated on 31 March 2014, which is before X-Trans III, 4 and 5 existed.
Trivial. The first line of the file says so in plain letters.
Do not assume it. The reference they check has no signature in it.
ExifTool reads the rest. For the shutter speed, the film simulation or the lens without opening a converter, ExifTool is free and prints every tag in a RAF as text.
Everything above in one block: the record, what the registry holds and where every fact on this page was checked.
Fujifilm has never published a RAF specification. Everything structural below comes from the libopenraw project, which worked it out from the files, and from the registry entry that cites libopenraw in turn.
| Item | Value |
|---|---|
| Extension | .raf |
| Stands for | Fujifilm raw |
| Kind | Camera raw photo file |
| Developer | Fujifilm |
| Specification | Never published. Reverse engineered by libopenraw |
| Magic number | FUJIFILMCCD-RAW, 16 bytes at offset 0 |
| Fixed fields | 0201 at offset 16, FF389501 at offset 20 |
| Camera model | Plain ASCII, 32 bytes at offset 28 |
| Byte order | Big endian, called Motorola order |
| Container | Fujifilm's own, not TIFF |
| Blocks | JPEG preview, meta container, CFA sensor data |
| TIFF inside | Yes, holding the CFA block only |
| Mosaic tag | 0x131, which records the X-Trans pattern |
| Usual sensor | X-Trans, an irregular 6 by 6 color filter array |
| First X-Trans camera | Fujifilm X-Pro1, announced 9 January 2012 |
| Sensor generations | X-Trans 2012, II 2013, III 2016, 4 in 2018, 5 in 2022 |
| Also written by | Bayer bodies (X-A, X-T100, XF10, GFX) and older EXR compacts |
| Compression | Uncompressed, lossless compressed, or lossy compressed |
| Format registry | PRONOM fmt/642, Fujifilm RAW Image Format |
| Registry classification | Image (Raster) |
| Registry signature | None recorded, despite 16 bytes of fixed ASCII |
| Registry updated | 31 March 2014, from a libopenraw citation |
| Free software | X RAW STUDIO, RAW FILE CONVERTER EX, darktable, RawTherapee |
X-Trans itself, the moire reasoning and five sensor generations come from Wikipedia's article on the Fujifilm X-Trans sensor. Its article on the Fujifilm X series lists the Bayer bodies.
Header layout, offset directory, three blocks and meta tags all come from libopenraw. Registry identifier, classification and that March 2014 date sit on PRONOM at The National Archives. The watercolor quotation and the Camera Raw 7.4 fix are from DPReview, 25 February 2013. Its description of X RAW STUDIO using the camera's own processor is from January 2025. The compression figures come from a worked comparison of the three Fujifilm raw settings.
Check the dates. Section 5 opens with the usual culprit.
That is the raw. Section 6 explains the preview you remember.
Want the step behind the colors? NEF files from Nikon cover how a camera works out two missing colors at every pixel. Same job, different mosaic.
Shooting more than one brand? ARW files from Sony, the Canon CR2 file format and the older Canon CRW format answer the same questions for the other bodies in your bag.
Thinking about an archive? Adobe DNG files are where most converted raw ends up, and that page covers what the conversion costs you before you start.
Stuck on the machine rather than the picture? Our Windows error guides and our macOS fixes work back from whatever the error says.
New to raw files altogether? What a file format is sets out the ground this page stands on, and our file format guides list every other extension we have covered.
Got a RAF that none of this explains? Send us its first line and your camera model and we will tell you what you are holding.