RAW Image Formats Explained: CR3, NEF, ARW, RAF and the Rest

Every camera maker invented its own RAW format, which is why your photos open perfectly on one computer and show up as blank grey squares on another.

A single RAW file shown split down the middle, grey sensor mosaic data on the left half and the same frame developed into a colour sunset landscape on the right

A RAW file is what your camera's sensor actually recorded, before anything was decided about it.

A JPEG is that same data after the camera made all of those decisions for you and threw the rest away.

That single difference explains everything else on this page.

What a RAW File Actually Contains

Camera sensors do not see colour. Each photosite sits behind a red, green or blue filter arranged in a repeating grid, so what the sensor records is really a brightness map with colour implied by the pattern.

Turning that into a picture takes a step called demosaicing, where software works out the two missing colours at every position by looking at the neighbours. Shoot JPEG and your camera does this instantly, adds its own sharpening, noise reduction and colour treatment, then compresses the result to 8 bits per channel.

Shoot RAW and none of that happens yet. You get the sensor readout, the full bit depth, and a complete record of the settings the camera was using, with every decision still open.

Why Bit Depth Is the Whole Argument

An 8-bit JPEG stores 256 brightness levels per colour channel. A 14-bit RAW file stores 16,384.

That is 64 times more tonal information in the same photograph, and it is where every practical advantage of RAW comes from.

Most current cameras write 12-bit or 14-bit files, sometimes switching between them depending on drive mode. True 16-bit capture exists, but it is medium format territory rather than anything you will find on a normal body.

What That Buys You in Practice

Recovery room. Shot a sunset where the sky looks right and the foreground is a black silhouette? A RAW file usually still holds detail down in that shadow, and lifting it looks like an edit rather than a mess of noise and banding.

White balance after the fact. Indoor shots that came out orange and snow that came out blue are both a one-slider fix in RAW, because the white balance was never baked in.

Edits that are not permanent. RAW developers do not rewrite your file. Your adjustments are stored as a list of instructions alongside it, so you can undo everything years later and start again with better technique.

That last one is worth dwelling on. A JPEG degrades a little each time it is edited and re-saved, because it gets re-compressed every time - a RAW file never does, because the original data is never touched.

Every RAW Format, by Brand

This is the part people actually come looking for. Find your extension in the left column.

Extension	Brand and cameras	Worth knowing
.CR3	Canon mirrorless and recent DSLRs, from the EOS M50 onward	Built on the same container family as MP4 rather than TIFF, and more space-efficient than CR2
.CR2	Canon DSLRs from the mid-2000s to the late 2010s	TIFF-based and supported by essentially everything, which makes it the safest older format
.CRW	Early Canon EOS digital and some PowerShot models	Obsolete, and modern software support is patchy - convert these to DNG while you still can
.NEF	Nikon DSLRs and Z-series mirrorless	Offers compressed, lossless-compressed and uncompressed modes, plus reduced-resolution options
.NRW	RAW-capable Nikon COOLPIX compacts	A different format from NEF despite the same brand, and it needs its own decoder
.ARW	Sony Alpha, across mirrorless and the older SLT bodies	14-bit, with compressed and uncompressed options on most recent models
.RAF	Fujifilm X-series and GFX	The X-Trans sensors use a non-Bayer filter pattern, so some converters render them noticeably better than others
.RW2	Panasonic Lumix	Well supported, and Panasonic ships lens correction data inside the file
.ORF	Olympus and OM System	Micro Four Thirds files, so noticeably smaller than full-frame equivalents
.PEF	Pentax	Pentax bodies can also write DNG directly, which is the easier option if your software struggles
.DNG	Leica, Ricoh, Sigma fp, most drones, and Apple ProRAW on iPhone	The open format, documented publicly, and the one most likely to still open in twenty years
.3FR and .IIQ	Hasselblad and Phase One medium format	Genuinely 16-bit, and usually handled best by each maker's own software

How to Tell Which One You Have

Right-click any file from your card, open Properties, and read what comes after the dot. That extension is the only thing that matters here, and it decides which decoder or app you need.

If File Explorer is hiding extensions, turn them on in the View menu under Show. Guessing from the camera brand alone is what trips people up, because Nikon and Pentax each write two different formats.

DNG: The One Format Nobody Owns

Adobe's Digital Negative format holds the same kind of sensor data as any proprietary RAW file, but its specification is published openly rather than reverse-engineered by every software vendor in turn.

That matters for archives. Proprietary formats depend on their manufacturer continuing to care, and CRW is already a cautionary tale about what happens when that stops.

Adobe DNG Converter is free and turns almost any RAW file into DNG without losing the original data. Several makers, including Leica, Ricoh and most drone manufacturers, skip the middle step and write DNG straight out of the camera.

The archiving move worth making.

Convert to DNG, but keep the originals until you are confident. DNG is the format most likely to still open decades from now, and converting costs nothing but disk space.

If you are on Windows 7 and just want DNG thumbnails in File Explorer, the old Adobe DNG Codec still does that job, though it has not been updated since 2012 and newer Windows has better options.

RAW, JPEG and HEIF Compared

JPEG wins on convenience and nothing else. The files are roughly five to ten times smaller, they open anywhere without help, and they need no processing before you can send one to somebody.

HEIF is the modern replacement for JPEG rather than a rival to RAW. It compresses better, supports 10-bit colour, and is what your iPhone writes by default - but the camera has still made every decision before the file is saved.

If Windows will not open the .heic files off your phone, that is a separate and well-documented problem, and HEIF Image Extensions is the official fix.

When Windows Refuses to Open a RAW File

Windows has no built-in understanding of camera RAW, so every format needs something installed before File Explorer will draw a thumbnail.

Illustration of a customs inspector examining a sealed crate with an unreadable label, beside three cards naming why Windows will not open a RAW file: a camera too new, no decoder for that brand, and a Windows version too old

Start with Raw Image Extension. Microsoft's own decoder covers Canon, Nikon, Sony, Fujifilm and more than a hundred other formats in a single install, which makes it the right first move for almost everyone.
Check whether your camera is simply too new. Support for a newly released body can take months to arrive, and converting those files to DNG is the reliable workaround in the meantime.
Restart File Explorer afterwards. Thumbnails do not refresh on their own, so open Task Manager, find Windows Explorer and click Restart.

Install Raw Image Extension

If you would rather not go through the Microsoft Store, SageThumbs is a shell extension that generates previews for a very long list of formats.

The other route is one decoder per brand, which is the better option on older Windows builds that Microsoft's extension will not install on:

Canon RAW Codec for .CR2 and older Canon files.
NEF Codec for Nikon .NEF, with .NRW needing a separate one.
Sony RAW Codec for .ARW files.

Nikon owners with a specific problem should read which Nikon codec or app you need, which covers that brand properly.

Software That Develops RAW Files

A decoder gets you thumbnails. Developing the file into a finished photograph needs an actual editor, and the free ones are genuinely good now.

Free and open source:

RawTherapee - the deepest control of the three, with excellent detail and noise tools, and no help file to speak of.
darktable - a full library plus editing workflow, closest in shape to Lightroom, on Windows, macOS and Linux.
RapidRAW - lightweight and fast, built to develop files quickly rather than to retouch them pixel by pixel.

Free, from the camera makers:

Canon Digital Photo Professional - matches Canon's in-camera colour exactly, and includes Digital Lens Optimizer.
Nikon NX Studio - reads NEF and NRW natively, carries Picture Control settings through from the camera.
Fujifilm X RAW Studio - unusual approach, using your connected camera's own processor to render Film Simulation colours.

Paid options exist too, and SILKYPIX RAW Converter is the shareware one hosted here, aimed at people converting RAW to high-quality DNG.

For a quick look rather than an edit, a viewer beats an editor - these three read common RAW formats directly:

FastStone Image Viewer - full-screen browsing with EXIF on tap.
XnView - over 700 formats, plus batch rename and convert.
IrfanView - the lightest of the three, extended by its plugins pack.

What RAW Actually Costs You

Storage, mostly. A 24-megapixel body writes somewhere around 25 to 30MB per frame, and a 45-megapixel one closer to 45 to 60MB, depending on whether compression is switched on.

Three hundred frames from a day out at 30MB each comes to roughly 9GB. That is one wedding, one holiday, or a couple of enthusiastic afternoons, so an external drive stops being optional fairly quickly.

The other cost is time. Every RAW file needs developing before anyone else can see it, and there is no version of this workflow where you shoot, then immediately share.

Who Should Stay on JPEG

Anyone who never edits. If your photos go from the camera to a phone screen untouched, RAW adds work and storage cost for a benefit you will never collect.

Anyone shooting long bursts. Check your camera's buffer depth in RAW versus JPEG - if the figure drops from hundreds of frames to a dozen, sports and wildlife will be frustrating.

Anyone who needs to hand files over immediately. Press, events and anything on a same-day deadline usually runs RAW plus JPEG together, so the JPEGs go out while the RAW files wait.

Anyone with one file to convert, once. Installing an editor is overkill - convert RAW to JPEG or PNG online and get on with your day.

What Is Coming Next

Phones have quietly become the biggest RAW platform there is. Apple's ProRAW and the equivalents on Android write DNG files that already carry computational processing, which is a genuinely new middle ground between RAW and JPEG.

Video is going the same way. Blackmagic RAW and its rivals give filmmakers the same after-the-fact control over exposure and white balance that photographers have had for twenty years.

Quick questions

Is RAW always better than JPEG?

Better in data, not always better in outcome. If you never edit your photos, a well-exposed JPEG straight from a modern camera will look just as good and take up a tenth of the space.

Which RAW format does my camera write?

Right-click a file from your memory card and open Properties to read the extension. Do not go by brand alone, since Nikon and Pentax each write two different formats depending on the model.

Can I convert RAW to JPEG for free?

Yes, and several ways. Any of the free developers listed above will export JPEGs, and for a single file an online converter saves you installing anything at all.

Should I convert everything to DNG?

It is a sensible archiving habit, because DNG is openly documented and proprietary formats depend on their manufacturer continuing to support them. Keep your originals alongside the DNGs until you are sure nothing was lost.

Why does Windows show my RAW files as blank icons?

Windows ships without RAW support, so nothing draws those thumbnails until you install a decoder. Raw Image Extension covers most brands in one go, and a File Explorer restart afterwards is what makes the change visible.

Should I shoot RAW and JPEG together?

It is a reasonable compromise if your card and buffer can take it, giving you something to share immediately and something to work on later. The cost is roughly a third more card space per frame.

More free RAW converters, editors and image viewers are listed in the Graphics section.