With the booming sales of digital cameras has come an increased interest in the quality of the digital product and how to achieve the best outcome. That has led to the increasing adoption of the RAW format for digital photographs.
What is RAW format?
Put very simply it is the basic unchanged - raw - data output of the colour sensitive pixels of the image sensor before it is processed and converted to 8-bit JPEG or 16-bit TIFF format for storage on the memory card. RAW data from most high end digital camera contains 12 bit data, which means that there can be 4096 different intensity levels for each pixel, whereas an 8-bit JPEG file can have only 256 different intensity levels.
There is no standardised RAW format and each camera maker typically
produces a proprietary format. It is mainly only high-quality cameras
that can save and export RAW files.
If the data is stored as a JPEG file it is modified in the camera
for
parameters such as white balance, saturation, sharpness, contrast
etcetera and subject to JPEG compression. A JPEG file is smaller, and a
very common format that is universally recognised in the computer
world.
TIFF files are larger than JPEG files, but they retain the full
quality
of the image. They can be compressed or uncompressed, but the
compression scheme is lossless, meaning that although the file gets a
little smaller, no information is lost.
RAW files are processed on a PC, allowing users to adjust the exposure and color after the image has been captured. If you save the RAW data, you can then convert it to a viewable JPEG or TIFF file at a later time on a PC. Software such as Adobe Photoshop can convert RAW to other formats to produce better quality photos than those produced in the camera.
Microsoft says it plans to deliver native support for digital camera
RAW images in the next major version of Windows, code-named "Longhorn."
It will also distribute a RAW Image Thumbnailer and Viewer for
Windows
XP, letting users work with thumbnails, previews, and metadata display
of Canon and Nikon RAW images directly in Windows Explorer. This tool
will be available soon for free download at http://www.microsoft.com/
For a fuller explanation of this topic visit:
http://www.microsoft.com/windowsxp/using/digitalphotography/expert/rawfiles.mspx
http://www.bobatkins.com/photography/digital/raw.html