What are RAW images and the different raw image file formats?

RAW images are uncompressed digital photos that save image data exactly the way the image was captured by camera's sensor.

By default, most digital cameras apply exposure and color temperature adjustments immediately when the photo is taken. The resulting image is then saved in a compressed format (typically as a JPEG file) to the camera's memory card. However, when shooting in RAW mode, the exposure and color temperature settings (i.e. white balance) are not applied to the image and the photo is saved in an uncompressed format. The resulting image is called a raw image or "camera raw" file.

Because raw images are not compressed, they take up significantly more disk space than their JPEG counterparts (usually at least twice as much). However, because the original image detail in raw images is not compromised by image compression, they are higher quality than JPEG images. While the typical user may not notice the difference in image quality, professional photographers often shoot in RAW mode to maintain the best quality for each image they take.

Because digital cameras store raw image data directly as it is captured by the camera's sensor, cameras made by different manufacturers save raw images in different formats. While it can be difficult to keep track of the various RAW formats, most image-editing programs that support raw image files (such as Adobe Photoshop CS) can import most, if not all, of the raw formats available. Below is a list of common raw image file formats used by various digital camera manufacturers.

Raw Image Formats:

Company Extension Notes
Adobe .DNG Digital Negative format developed by Adobe Systems; designed to be a standardized format for archiving RAW images that is supported by multiple programs.
Canon .CR2, .CRW CR2 format is based on the TIFF file format, CRW is based on the Camera Image File Format (CIFF); both viewable with bundled ImageBrowser and ZoomBrowser software.
Fuji .RAF Fuji raw format that is editable with the Fuji Hyper-Utility software included with most Fuji cameras.
Kodak .DCR Kodak raw format that can be edited with Kodak Custom Looks Software.
Minolta .MRW Minolta raw image file format that is viewable with Dalifer software.
Nikon .NEF Standard Nikon raw format that can be opened with Nikon View and edited with Nikon Capture.
Olympus .ORF Olympus raw image format that is editable with Olympus Master or Olympus Studio software.
Pentax .PEF Raw image format known as the "Pentax Electronic Format," which is used by Pentax cameras; can be viewed with Pentax Photo Browser software.
Sony .SRF Raw format used by high-end Sony cameras like the DSC-F828; editable with included Image Data Converter (IDC) software for Windows.

Additionally, the RAW format is a type of raw image that is not saved by a specific digital camera manufacturer, but may be imported and exported by various image editors.

Know of another raw image format that should be listed here? Suggest a format.