CRW File Format (.crw)

A CRW file holds raw sensor data in Camera Image File Format, the CIFF container Canon specified in February 1997 and used for its early PowerShot compacts and its first digital EOS bodies until the TIFF-based CR2 format replaced it in 2004.

.crwImage Files

CRW at a glance#

Full name	Canon Digital Camera Raw Image Format
File extension	.crw
Category	Image Files
Developer	Canon Inc.
First released	1997
MIME types	image/x-canon-crw
Compression	Lossless
Specification	CIFF Specification on Image Data File, version 1.0 revision 4
FileFlip support	FileFlip reads this format but does not write it

What a .crw file can hold#

These are the things a CRW file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.

Lossless compression	Yes
Embedded metadata	Yes
Colour profiles	Yes

Strengths and limitations of CRW#

What CRW does well

Canon's Huffman coding of the sensor data is lossless, so every value the camera recorded comes back intact when the file is decoded
The 3 to 8 megapixel sensors of the CRW era produce files of a few megabytes, a fraction of what a current camera writes per frame
Free decoders including LibRaw, dcraw, darktable and RawTherapee read CIFF, so no paid software is needed to open an old archive

Where CRW falls short

Canon moved to CR2 during 2004, so no camera built since then writes CRW
CIFF has nothing in common with TIFF, so raw software has to carry a separate decoder for CRW rather than reusing the one it already has
The EOS bodies that wrote CRW digitize at 12 bits per pixel, below the 14 bits Canon's later raw formats record

Nobody chooses CRW today; it turns up when opening an archive shot on an EOS D30, D60, 10D or 300D, or on a PowerShot G-series or S-series compact from the same years.

Convert CRW to DNG when archiving old photos so they stay readable by software that no longer bothers with CIFF, or to JPEG when the picture just needs to be shared.

How to open a .crw file#

A .crw file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts CRW into a format your machine already opens, and it does it in the browser tab rather than on a server.

Platform	Programs that open it
Windows	Adobe Photoshop, Adobe Lightroom Classic, IrfanView, XnView MP
macOS	Adobe Photoshop, Adobe Lightroom Classic, Adobe Bridge, Preview
Linux	darktable, RawTherapee, digiKam
Web	FileFlip

CRW questions people ask#

What camera made a CRW file?

CRW came from Canon's first digital SLRs and several early PowerShot compacts, specifically the EOS D30, D60, 10D and 300D, the PowerShot G1 through G6, the PowerShot S30 through S70, and the PowerShot Pro1. Canon switched to CR2 in 2004, so a CRW file is at least two decades old, and its EXIF data names the exact body.

What software still opens CRW files?

Adobe Photoshop, Camera Raw and Lightroom Classic still decode CRW, as do the open-source raw tools built on LibRaw and dcraw, including darktable, RawTherapee and digiKam. Canon shipped Digital Photo Professional and ZoomBrowser EX with the cameras that wrote CRW, though the current versions of Canon's software are aimed at newer bodies.

What is the difference between CRW and CR2?

CRW uses Canon's CIFF container, which identifies itself with the marker HEAPCCDR in the first bytes of the file and is unrelated to any other image format, while CR2 is built on TIFF and stores the sensor data as lossless JPEG. Canon changed over in 2004, and the two need separate decoders even though both hold Canon raw data.

Should I convert CRW files to DNG?

Converting CRW to DNG is worth doing for long-term storage, because DNG has a published specification while CIFF support depends on decoders that were reverse-engineered years ago. The conversion carries the sensor data across without re-rendering it, so image quality is unchanged, and some Canon-specific metadata is what gets dropped. Adobe only published DNG in 2004, by which point Canon was already moving from CRW to CR2, so shooting DNG was never an option on these cameras.

Converting CRW files#

FileFlip does not write .crw files, so nothing on the site converts into this format. It works as a source only.

Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.