What Is a CRW File? Canon's First RAW, Explained
A CRW file is where Canon RAW began. From roughly 2000 to 2004, Canon's first digital EOS bodies — the D30, the D60, the 10D, the original Digital Rebel — wrote .CRW when you shot RAW, and so did the early PowerShot G and S compacts. Like every RAW format that followed, a CRW is a digital negative: the sensor's unprocessed readings from the moment of exposure, plus metadata, waiting for someone to develop them into a photograph.
Unlike nearly every RAW format that followed, CRW isn't built on TIFF — Canon used its own CIFF structure. Twenty years on, that pedigree matters for one reason above all: getting the files open. If you've just found a card or a folder of .CRW files from the early 2000s, here's what they are and how to bring the photographs back on a modern Mac. Short on time? See how to open CRW files on a Mac.
CRW at a glance
| Full name | Canon RAW, first generation |
|---|---|
| Extension | .CRW, often paired with a small .THM sidecar |
| Introduced | Around 2000 |
| Written by | EOS D30, D60, 10D, the original 300D Digital Rebel, and PowerShot G1–G6, Pro1, Pro70 and S30–S70 |
| What it holds | Unprocessed sensor data and metadata, with the thumbnail carried in the .THM sidecar |
| Structure | Canon's own CIFF container — not TIFF-based like most later RAW formats |
| Typical size | Small by modern standards — these were 3–8 MP cameras; public samples run 3–11 MB from the EOS bodies and 2–9 MB from the PowerShots |
| Opens with | RAW editors that kept CRW support, RevelRaw among them; Adobe's free DNG Converter as a fallback. Support elsewhere is thinning — see below |
What's actually inside a CRW file
A camera sensor doesn't record a picture. Each photosite records how much light hit it through a single-color filter — red, green or blue — arranged in a mosaic. A CRW file stores those readings as they came off the sensor:
- The mosaic sensor data. One brightness value per photosite. No white balance, no sharpening, none of the camera's color settings have been applied yet. Turning this mosaic into a viewable photograph is the job of your RAW editor — which is why a twenty-year-old CRW can still be developed with today's tools, better than the camera ever managed.
- Metadata. Camera body, lens, exposure settings, and the picture parameters you had dialed in. Editors read this to know how to interpret the data; nothing in it is baked into the pixels.
- A sidecar thumbnail. Most CRW-era cameras wrote a small .THM file next to each .CRW, holding the thumbnail and some metadata. It isn't junk — keep each pair together when you copy the archive.
Rescuing a CRW archive
Modern software support for CRW is thinning: each new release of the big editors and of macOS itself is written with current cameras in mind. Apple's current list still includes the EOS D30, D60, 10D and Digital Rebel and the PowerShot G3, G5, G6, Pro1, S60 and S70, and in our macOS 27 test, files from all of them opened with the Mac's own RAW support — as did the G2, which Apple's web page leaves out. The PowerShot G1, Pro70 and S30 to S50 didn't open, so Finder and Preview show nothing useful for them — but a blank thumbnail doesn't mean the file is broken. The negative is almost certainly intact; it's the viewer that has moved on.
Three habits will keep the archive safe. First, get the files off aging CDs, cards and drives and onto storage you trust, keeping every .THM with its .CRW. Second, open them in an editor that still reads CRW and export the keepers to a modern format. Third, if a CRW won't open anywhere, convert it once to DNG with Adobe's free DNG Converter — DNG opens almost everywhere — and keep both files, the DNG for working and the CRW as the original.
How to open CRW files on a Mac
The reliable route is a RAW editor that still supports the format. RevelRaw is built around Sony Alpha, but it opens Canon CRW files all the same: drag one in or pick it from File > Open, and AI scene detection ranks 50+ presets against your photo, with the standard fine-tune controls on top. Everything runs on your Mac; no file ever leaves it — a twenty-year-old family archive stays exactly as private as it was in its shoebox.
Whether Preview and Photos open a CRW on their own depends on the camera that wrote it. Our step-by-step guide to opening CRW files on a Mac is the full, tested walkthrough: a ten-second check for your camera, what every CRW body did on macOS 27, and what works when a file won't open. If nothing on your Mac will read a particular file, the DNG Converter route above gets it open.
How to convert CRW to JPEG
Open the file in a RAW editor and export. RevelRaw exports JPEG, PNG, TIFF and HEIF, with platform presets for Instagram, print and web — so a rescued negative can go straight to a shareable file, developed properly rather than through 2003's in-camera processing. Whatever you export, keep the CRW and its .THM afterwards: the negative survived twenty years; it deserves to survive the conversion too.
→ Convert RAW to JPEG on a Mac (Any Camera, 2026)
FAQ
What does CRW stand for?
Canon RAW, first generation — the format before CR2 and CR3. It's built on Canon's own CIFF structure rather than TIFF, which most later RAW formats use.
Which cameras write CRW files?
Canon's first digital EOS bodies — the D30, D60, 10D and the original 300D Digital Rebel — plus PowerShot compacts: the G1 through G6, the Pro1, the Pro70 and the S30 through S70. Canon moved to CR2 with the EOS-1D Mark II and 20D in 2004; the last CRW compacts were the G6, S60 and S70.
What is the .THM file next to my CRW files?
A small sidecar holding the thumbnail and some metadata for its matching .CRW. Keep each pair together when you copy or move the archive.
What if a CRW file won't open in anything?
Convert it once to DNG with Adobe's free DNG Converter, which still reads CRW. The DNG will open almost anywhere — and keep the original CRW alongside it rather than replacing it.
Can RevelRaw open CRW files?
Yes. Drag a CRW in and it opens like any other RAW — presets, scene detection and fine-tune controls work. On the PowerShot G1, Pro70 and S30 to S50, which macOS can't read, Kelvin white balance is switched off; Warmth and Cast still work. Exports go out as JPEG, PNG, TIFF or HEIF.
Related reading: How to open CRW files on a Mac · All RAW formats RevelRaw opens · CR3, Canon's current RAW · CR2, Canon's DSLR-era RAW · What is an ARW file? · What is a NEF file?