Tech Features

The computer helper: Getting RAW with your digital camera

By Jay Dougherty May 23, 2006, 15:37 GMT

Washington - RAW is beautiful. So say digital camera aficionados who argue that to get the most out of your digital camera, you have to dispense with the typical jpeg files that most produce and turn instead to RAW. But most digital photographers don't know what RAW files are, or how to get started with them. Read on for some answers.

Q: What are RAW files?

A: RAW files are image files, just like jpeg, except that RAW files contain all the data that your camera's image sensor - the main light-gathering chip - records.

Think of RAW as a digital negative. With RAW files, no data is thrown away, interpreted or compressed, as it is with jpeg.

RAW files have various extensions, depending upon the camera from which they come. Canon cameras sometimes record RAW files with a '.tif' extension, while Nikon cameras often use '.nef' as the file extension. Read your digital camera owner's manual to find out how to identify the RAW files from your camera.

Q: Why is RAW better than jpeg?

A: RAW files leave you more latitude in processing an image after it's been captured. With RAW, you can often perform manipulations that previously had to have been done before you took a picture.

For example, you can adjust exposure, white balance, sharpening, colour, contrast, shadow levels, and much more after you've transferred the RAW file to your computer. With jpeg, many of these adjustments have been hard coded into the file you're given. While adjustments are possible, they're often not as easy to make.

Jpeg is also an 8-bit image file format, while RAW often records 16 bits of image data, meaning that a lot of information is 'thrown away' by your camera during the creation of a jpeg image.

Q: Do RAW files have any disadvantages?

A: Yes. RAW files take up more space on your memory cards, often significantly more - as much as two to three times the amount of space that a jpeg occupies. So you'll potentially need more memory cards for your camera, or you'll have to settle for being able to take fewer pictures at a time.

RAW files are also not recognised by all photo processing programs. So you may need to adopt a new application than the one you're currently using when working with image files from your camera. Most cameras that write RAW files as well as jpeg come with the software necessary to process them, however, so you should have something in your software library already.

Finally, it may take you longer to process a RAW image, both because the files are larger and because you may not be as familiar, at least initially, with the software you must use in order to work with a RAW file.

Q: How do I work with RAW files?

A: First, set up your camera so that it records images in its RAW format rather than in jpeg. Some cameras allow you to record images in both RAW and jpeg at the same time.

Then transfer your images from your camera to your computer as you normally do. Once transferred, use the software that came with your camera to look at and manipulate the image files.

Note that a growing number of off-the-shelf image editing programs, including the popular Adobe PhotoShop, can open and edit RAW files, as well.

Q: Are there software programs designed specifically to do a better job at working with RAW files?

A: Yes. In addition to the software that came with your RAW- capable camera, quite a few applications have been developed to meet the needs of the growing number of photographers who use RAW files exclusively. Most of these are available in trial versions so that you can download them and see whether they make a difference for you.

Capture One (http://www.phaseone.com) is one of the most established, but Bibble (http://www.bibblelabs.com) and RAW Shooter (http://www.pixmantec.com) have devoted followings, as well.

Q: The store where I have my digital photographs developed won't accept RAW files.

A: That's no reason not to use the RAW file format to capture your images. You can always use the software that processes your RAW files to output them in whatever format you need, including jpeg.

- Have a computer question? Send it to the Computer Helper at jayd@csi.com.