Digital camera RAW format

Week of January 30, 2005

Q: I purchased a Konica-Minolta Dimage A2 camera that is capable of taking pictures up to 8 megapixels. I really like the camera, but have not been able to use the 8 megapixel option because it produces RAW images. The info in the manual on working with RAW images does not make any sense to me. And I have not been able to find anything else on this. What can you tell me about RAW images and what do I need to work with them?
-Linda Burich, Minneapolis, MN

A: RAW is one of several image files produced by high-end digital cameras. The others are JPG, and sometimes TIFF. RAW offers many benefits to the advanced user, but requires a bit more interaction than a JPG or TIFF file.

When you camera creates a JPG or TIFF, the computer circuits in the camera take the information from the camera’s sensor and “develops” the picture before storing it on the memory card as a JPG or TIFF file. TIFF files do not use compression, which preserves image quality- but at a price. TIFF files are many megabytes in size, which will fill up your memory card very quickly.

RAW is exactly what it is called- raw data from the camera’s sensor. Instead of processing the digital data into a TIFF or JPG image, the camera records the information directly to the memory card without processing it into an actual digital image. When you download the RAW file to your computer, you use software to convert the RAW file into a JPG or a TIFF. (Please note the files are not usually called RAW, but have a designation from the manufacturer. For example, Canon RAW files are usually called CRW.)

By doing the conversion outside of the camera, you have much more control over the final image. When the camera takes the data and processes it to make a JPG or TIFF, it applies color correction, sharpening and other adjustments to produce the final image. A skilled user at a computer can do a better job at applying these corrections than a camera can. You also preserve 100% of the image quality, unlike a JPG which uses compression, and at a smaller file size than a TIFF.

Unlike JPG and TIFF, RAW files may be called RAW but they all differ by manufacturer. A Minolta JPG and a Canon JPG will be similar and any software program can work with them. Relatively few programs work with RAW files, and a Minolta RAW file will be entirely different than a Canon RAW. Photo processing labs you find at camera and department stores do not work with RAW files, so you have to convert them before printing.

Your camera came with software for Minolta RAW conversion called Dimage Viewer. You can use it to convert your RAW files to JPG or TIFF files, which you can use for printing, emailing or in other image editing programs.

The easiest way to work with RAW images is with Adobe Photoshop or Adobe Photoshop Elements 3.0, which offer RAW conversion for most cameras on the market. You can preview, convert and work with your images just like they were JPGs, but with the added control and quality of using the RAW format. You can learn more about the Adobe products at www.adobe.com.

Advanced users should check out Phase One’s Capture One DSLR LE , widely reputed to be the best RAW processing software available. It offers faster workflow as well as better final results compared to other programs I have seen. It sells for $99 at www.phaseone.com. You can download a no-charge evaluation copy before buying.

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