JPEG Vs. RAW: The Advantages and Disadvantages Explained

© Jonathan Barkey The top image is a JPEG that's partially corrected in Photoshop showing sub-optimal color balance. Bottom shot is a RAW image corrected in Adobe Camera Raw that exhibits good color balance.

If you own a digital SLR, you already know that your camera is capable of recording both JPEG and RAW file formats. You might assume that choosing one format over the other is simply a trade-off between convenience and quality. It isn't quite that simple.

True, JPEGs take up less space on a memory card and are ready to use straight from your camera, but they sacrifice image quality and processing flexibility to achieve these advantages. RAW files contain significantly more picture information than JPEGs but demand much greater storage capacity, special processing software, and extra work on the computer. While some of the advantages of your camera's RAW format seem obvious, others are less so.

Choosing the right format is largely a matter of what you intend to do with your pictures. Either of them may be the right format for the job, but you need enough information to make the right decision.

What's the Difference?

It helps to compare how a camera captures and stores JPEG and RAW files. The first thing to understand is that your D-SLR actually "sees" in black and white, since the millions of pixels on its imaging sensor measure only brightness, not hue. Color data is derived indirectly, from a checkerboard of minute red, green, and blue filters that covers the surface of the chip -- one color per pixel. This mosaic-like filter layer is known as a Bayer Pattern array.

When you take a picture, the camera immediately stores the original black-and-white brightness readings in its temporary memory buffer -- as a RAW image file. If you're shooting in RAW mode, that file immediately gets sent to your memory card without alteration. To actually do anything with it later, though, you'll need special processing software on your computer. But in JPEG mode, the camera does the processing itself, immediately, based on the image settings you chose from its on-screen menus or external controls. It combines the monochrome RAW data with the Bayer Pattern color information (stored in the form of a pixel-by-pixel color "map" in the RAW file's metadata); applies a tone curve; adjusts white balance and adds sharpening; and finally writes the ready-to-use, full-color JPEG to your memory card. It does all this, of course, in milliseconds.

The chief virtue of that JPEG image is that it's written in a universal file format readable by virtually any imaging program. Also key is that JPEGs are compressed -- their data is saved by grouping similar pixels together rather than treating each one individually -- which enables you to fit lots more shots on your memory card. And because the files are smaller, the camera can shoot more of them, more quickly.

The JPEG format also lets you e-mail or wirelessly transmit them with ease, a necessity for many news photographers. The problem with JPEG compression is that it's lossy, meaning that it throws out a certain amount of picture information (similar but not always identical pixels) in order to reduce file size. At the highest quality settings, JPEGs can be very smooth and sharp. But as you dial down your D-SLR's image quality, and thereby increase compression, "jaggy" artifacts begin to obscure fine image details. And as mentioned before, a JPEG has its white balance, sharpening, contrast and other image parameters set in the camera. The upside (convenient, ready-made pictures) is balanced by the downside -- that you can't go back and change image settings after you've shot a JPEG.

Again, a RAW file contains only the original, unprocessed picture data from your camera's image sensor. It's what the camera recorded without any modifications -- no fixed white balance, no sharpening, no contrast adjustment, no noise reduction. What's more, a RAW file is either uncompressed or only slightly squeezed with lossless compression, meaning that absolutely no actual picture information is thrown away. The RAW format also stores brightness data at 12 bits per color, just as the sensor recorded it, rather than JPEG's eight bits. That means it captures significantly more tonal information. (More about that later.)

In essence, a RAW file is of intrinsically higher quality than a JPEG. It allows you to make major changes to an image after you've shot it and still retain good quality. And in working with RAW, you never modify the original file. But -- and this is a big but -- that file requires two to ten times more storage space than a JPEG.