What’s the Raw Deal?
If Raw format (with extensions such as NEF in Nikon's version or CRW in Canon's) takes an extra step, why bother working with it? The answer comes in just what you can do with Raw files after they are downloaded to the computer. Raw file formats are uncompressed, like TIFFs, thus offer more image information than what you'd get in a JPEG. Every JPEG is compressed, which means that even with Fine or Super Fine, or whatever manufacturers like to call their lowest compression JPEG file, there is some tossing away of image information when the file is written to your memory card. This information goes away, and when the image is opened it is reconstructed using what are called algorithms, or presumptions of what those tossed-away pixels should look like. Woulda, shoulda, coulda--it's just not the original information. This might work fine on some images but those with lots of intricate details might suffer some loss, as will those with many subtle tonal gradations.
Now I know portrait photographers who insist that those Super Fine JPEGs are just fine, and if it works for you go for it. Perhaps Raw is just for purists, but why toss away information just to save a few seconds more work? It's your call.
In any case, how about just shooting TIFFs rather than RAW and not worry about losing information, seeing as TIFFs are non-compressed (lossless) file formats? Well, if you shoot with a high-res digital camera and knock out 24MB plus per exposure then your memory card will fill up fairly quickly, even if you have on of those 1GB cards that are now so affordable. The Raw format actually takes from 50-60% less space on your card and hard drive, giving you more shots per card. How do they do that? Because you defer image processing on Raw files until you get the image into the Raw converter software on your computer there are less instructions in the Raw file and less processing in-camera.
But it's what you can do with the image file after you get the Raw image into the computer where the real charm of Raw comes through. Open any Raw converter software and you'll see a raft of options, including white balance to the Nth degree, exposure compensation controls like you set them when you made the shot, switching between color spaces (from sRGB to Adobe RGB), getting 16-bit or 8-bit, defining resolution for printing (I set mine at 240), chromatic aberration and noise filters, and more. Indeed, working with Raw has been likened to being able to develop your own film, and certainly allows you to customize your image just as if you brought it into the lab and did clip tests like in days of old.
Now I'm not saying that Raw is the only way to go. I still shoot plenty of images on Fine JPEG. But for those images where I know I want all the information I can get, or when I want to play with customization of very frame, then I stick with Raw all the way down the line. And, in recent cameras, such as the EOS 1Ds Mark II I reviewed in the May issue of Shutterbug, you can choose Raw+JPEG with one push of the shutter release button. That allows me to go whatever route I desire after I download the images, with the simplicity of JPEG or the awesome image control options of Raw.