When I first got my digital SLR (
DSLR) in 2005, I didn't bother to read much about the RAW format. I set my camera on the highest quality JPEG (JPEG Fine in Nikonspeak) and went on with my business. I'd heard a little bit about RAW reading photography articles on the internet and books about digital photography, but at the time RAW just seemed like kind of a pain in the rear.
A RAW file is like a digital negative. It captures the raw image, literally. When you change the RAW file to a JPEG, or if you shoot on the JPEG setting, the resulting files are not the original data captured; rather the files consist of chunks of pixels that the JPEG process corrals together to produce a close approximation of what was originally shot. For a much more accurate description of what a JPEG is, go
here.
There's nothing wrong with JPEGs, in fact you must always convert RAW data to the JPEG format if you want to print a photograph shot in RAW, or if you want to upload the photo to the internet, or e-mail it or do just about anything with it. This is why I resisted the RAW format for so long. Usually I
do want to print or e-mail my images, so the notion that I'd have to convert each and every image from RAW to JPEG if I wanted to do anything with them just seemed like an annoying extra step to me at the time.
Another thing about RAW is that you must have RAW conversion software if you want to deal with that format. Most cameras come with software, but typically photographers who work a lot with RAW images don't use the "free" software that came in the box with their camera. I, for one, never loaded any of the software that came with my
Nikon D70 on my computer. I don't use it to download, I use a
card reader to do that, and I don't use it to process or edit photos- I use
Adobe Photoshop CS3. Photoshop CS3 comes with a plug-in called
Camera RAW, and I like it. There are other RAW processors out there-
Aperture, if you use a
Mac,
Lightroom, which is also made by
Adobe, or there is
Open Source software that will process RAW files as well, if you are into that sort of thing. I use Camera RAW because it works for me and it's part of my
million dollar Adobe CS3 software package and since I paid over $600 for the upgrade from CS2, I'm not in a hurry to go spend another $300 on
Lightroom or any other program.
Anyway, I digress.
Several of my photographer friends tut-tutted at me when I said I never shot in RAW, so I finally capitulated and gave it a try. Once I did, I asked myself why the heck I'd waited for so long?! Yes, it adds time to post processing, yes the files take up more room on the memory card. Wah! It's really not a big deal, those things. The versatility of RAW files more than makes up for the hassle.
When you open a RAW file in Camera RAW (and other RAW processors), you have very fine tune control over exposure, white balance, tonality, saturation, sharpness- etc.... Working with a RAW file is like working with a negative in the darkroom, only without all the smelly chemicals (I do miss those!). Everything you need to finesse your images is right there in the form of sliders and buttons. You can play with all of them and watch the effect they have in a large preview. CS3's Camera Raw even has the ability to recover blown out highlights (whites that are too harsh)- something that would be utterly lost in a JPEG. It has another slider called "Fill Light" which I quite like too.
Once you've adjusted the image to your liking, you can have it open up in Photoshop and from there save it as a JPEG to print or put on the web.
The example below illustrated just how effective editing an image in Camera RAW can be. The first photograph I deliberately shot on the wrong white balance setting. I was shooting with natural light, and I set my camera's white balance to tungsten (otherwise known as indoor/incandescent lighting). As you can see, the shot has an ugly blue cast to it. Had I shot the photo in the JPEG format, I could have tweaked the color balance in Photoshop a little, adding yellow to take some of that blue out, but it wouldn't completely fix the shot.
Notice also how the image's whites are pretty harsh, especially on the left hand side of the vase.

Now look at what happened when I changed the white balance to daylight within Camera RAW, plus used the Recovery slider to bring back some definition to the whites. I was pretty amazed with the results. This shot looks just like some others I took during the same shoot with the white balance set correctly.

These shots were taken during a demo I gave to my
Intermediate Photography class about
hot lights. Hot lights provide a constant source of light, often used for product photography and sometimes portraits. They are much cheaper than
strobe lights, so they are popular with people who set up small photography studios in their home, or for photographers that don't have big budgets for strobe lights. In order to shoot with these lights, you must set your camera's white balance to tungsten. During this demo, I took some of my shots with just the existing light coming in through the window from outside, and some of my shots with a hot light. When switching back and forth between daylight and tungsten lighting, it's easy to forget to set your white balance back to daylight once you finish shooting with hot lights. You can tell that you have it set incorrectly if you look at the image on your camera's LCD screen once you've taken the photo, but sometimes in the flurry of the moment, we forget. Sometimes too, lighting situations are very tricky, or you might find yourself having to shoot in mixed lighting, and in those situations you might really need to custom tweak each shot to make it look right after the fact. Camera RAW. It's a good thing.