I wasn't going to re-hash the details of "RAW vs. JPEG", since it's already so well-covered elsewhere. But then, I remembered that I had written about this about 2 months ago, so I figured I'd just cut & paste here...
RAW is the original image data captured by your camera's sensor. If you shoot JPEG, your camera takes the original RAW data and throws away about 7/8 of that data to produce the final JPEG image. (I'm not sure about the exact fraction, but that's how it was explained to me by a professional photographer)
If you shoot JPEG, you're letting the camera's on-board computer decide how to convert the RAW file to JPEG. On the other hand, if you shoot RAW, you get to control how you want to process the RAW file into your final JPEG image. In addition, your own home computer has tons more processing power than the little computer in your camera.
Warning: Nerdy math stuff ahead:
If you shoot JPEG, it's an
8-bit image. What does this mean? Each image is composed of different shades of red, green, and blue (hence, RGB). The term "8 bits" refers to 2^8 (2 to the 8th power) = 256. This means you get 256 shades of red, 256 shades of green, and 256 shades of blue. That sounds like a lot! And when you combine these different shades of colors, you can potentially create
16.8 million colors in an 8-bit JPEG file (here's the math: 256 red x 256 green x 256 blue = 16.8 million possible colors). That, too, sounds like a lot of colors!
If you shoot RAW, it's likely a
14-bit image. "14 bits" refers to 2^14 (2 to the 14th power) = 16,384. That's 16,384 shades of red; 16,384 shades of green; and 16,384 shades of blue! And combined together, you can potentially create
4.4 trillion colors (16,384 red x 16,384 green x 16,384 blue)!
Why is this important? Any time you do any image processing on your computer, you'll end up changing the tones of the image. Because JPEG images have relatively fewer tones / colors, you may run the risk of "posterization", which are abrupt (often ugly) changes in tone. Here's an example of posterization in the sky:
If you shoot in RAW and you make adjustments to your images, you have much less risk of posterization since you've got so much data you're working with. As a result, your final images will have much smoother tonal gradations.
Whew!
Oh, a couple more things. If you decide to shoot in RAW, sometimes there's extra information hidden in parts of the image that appear "blown out". For example, if you took a picture of a forest and the sky appears way too bright (or, "blown out"), sometimes, you can actually "recover" some of the image from the blown-out areas, resulting in a more realistic-looking sky. You can sometimes do the same thing with dark shadow areas, too. However, if you shoot JPEG, you'll have less success recovering details from the bright highlights and shadows.
The other advantage of RAW is that
white balance isn't "baked in" or processed as part of the image. Have you tried taking a photo indoors and found the picture to have a yellow tint? This is a white balance issue. If you shot in JPEG, it's much harder to correct the color because the white balance is already part of the JPEG image. If you shot the image in RAW, you can very easily change the white balance of the image to achieve the correct color for that image.
Why doesn't everyone just shoot RAW? There are some advantages to shooting JPEG:
- It's a standard format, so my JPEG image can be viewed on anyone's computer and can be printed on any printer.
- A JPEG file is lots smaller than a RAW file, so you can fit TONS more JPEG images on your memory card.
- If you're a sports photographer, you can shoot a HUGE burst of JPEG shots before the camera's buffer gets overwhelmed (whereas, if you shoot RAW, you can maybe shoot a dozen RAW photos before your camera freezes painfully for several seconds).
- If you don't care to do any processing of your images, then your JPEG images are ready to be used right away (ie. you can upload them immediately to your Flickr account, burn them onto a disk, e-mail them to family, post them on Disboards, etc).
If you do decide to shoot RAW, you'll need a special program that'll allow you to open the RAW files, process the RAW images, and then convert them to JPEGs. Your DSLR camera should have already come with a CD that provides a RAW processing program for free. For example, Canon provides its Digital Photo Professional (DPP) on a CD.
Other popular programs for processing RAW files include Apple's Aperture, Adobe Photoshop & Photoshop Elements (both of which include Adobe Camera Raw), and Adobe Lightroom. (there are many others, but these are probably the most popular)
Okay, this post ended up being way too long and probably way too technical. Hope I didn't bore you with all this. I guess that's why "RAW vs. JPEG" stirs up such heated debate.
They were still wrong (Jpegs) and not the 1 jpeg and 1 Raw file I was supposed to be seeing.
