A RAW image file is often referred to as a true digital negative. The option to shoot RAW is available on many advanced and professional digital cameras. Images in this format have a .raw extension, eg: filename.raw.
There is much more latitude controlling exposure than with JPEG files. When shooting RAW, no processing is done in the camera to the file. As a result, the photographer has total control adjusting elements, such as sharpening or white balance, when processing a RAW file during editing.
When editing a RAW image, no changes are made to the actual file. A separate file is created and all adjustments are kept in the associated file.
The RAW format, considered essential by professional and serious photographers, is still not widely used by others. At this time, RAW files can not be opened with every image editor and can take longer to process when editing that JPEG files.
In 2004, Adobe introduced the Digital Negative (DNG) format, an open standard RAW file format. Adobe and others want the DNG to become to standard format for RAW files generated by digital cameras.
A RAW image has a smaller file size than a TIFF but is considerably larger than a JPEG.
sRAW and mRAW
Digital cameras with sRAW and mRAW give photographers the option to shoot RAW image files at reduced size. While they have lower resolution than RAW, the smaller file allows more images to be captured on a memory card and there can be an increases in speed when using burst mode.
But my digital camera doesn’t shoot RAW!
If you’re concerned because your camera doesn’t shoot RAW, don’t worry. Many digital camera users find JPEGs, when shot at the highest resolution and lowest compression settings, meet their expectations for image quality. Many also find JPEGs easier to edit than RAW images.
Some digital cameras have an option to take both RAW and JPEG images simultaneously (JPEG + RAW setting). If you generally prefer to shoot JPEG only, consider shooting JPEG+RAW for special events or when lighting is difficult in case enhanced image editing is needed.