In this lesson: Learn to save your image files in the appropriate format

Understanding the differences between RAW and JPG image file formats can open up a whole new world of possibilities for your images. But to do that, you’ll need to explore the advantages and disadvantages of both formats to determine which one to use for what purpose.

DSLR cameras and many point and shoot cameras are capable of storing image files in two main formats: RAW and JPG (also denoted as JPEG). Most will also allow you to select the level of quality for the JPG option and many will allow you to save both a RAW and high-quality JPG file of each image. Understanding the differences between the formats will help you decide which format(s) work best for you in different situations.

RAW Files in a Nutshell

The RAW file format preserves all of the data recorded by each pixel in the image sensor. This means that all the color and luminosity information in the scene is available when you open the file. An advantage of this is that the abundance of data gives you the greatest amount of control over the appearance of the image in post-processing. The disadvantages to this format lie in much larger files that take longer to write to the recording buffer and the use of more storage space on memory cards and hard drives. Additionally, there is no “standard” RAW file format; each camera manufacturer has its own proprietary format. Fortunately, most modern image editing software applications, including several free ones, will open multiple RAW formats.

Also note that when opening a RAW file for the first time, you’ll likely notice that the image seems quite flat, with drab colors and little contrast, as seen in the sample image of the steel cables. However, this is because the file hasn’t yet been processed. Once you put the image through processing, the colors and contrast will come to life.

Best use for RAW: RAW files are preferred when you want maximum creative control over your images.

Primary disadvantage of RAW: File size. RAW files keep all the data collected by the sensor, so file sizes are extremely large and will take up more room on storage devices.

JPGs in a Nutshell

The JPG file format is a “lossy” format that discards some image data in order to compress the image into a much smaller file. The JPG standard allows you to determine the amount of compression that takes place, but not which data is discarded. In short, a processor in the camera uses a preset algorithm to adjust brightness, color balance, and contrast, and discards pixel data that’s determined unneeded in the final image. That’s why JPGs at first appear much more vibrant and lively, like the sample image of the blue stairs, yet have a smaller file size. Obviously, this loss of data is the chief disadvantage in using JPG files, since that information can’t be recovered in order to make adjustments in processing.

JPG conversion also may reduce the resolution of an image as low as 72 pixels per inch, depending on the camera and software settings. This lower resolution is suitable for screen display, but not for printing. Finally, JPG files may develop “artifacts” or blurry areas around portions of an image, caused by over compression. This does not mean that JPGs are without their advantages:  their file type is portable to other applications, such as email and digital displays. The JPG format is recognized by virtually all viewing and editing software. And, as noted above, JPGs take up far less space on memory cards and hard drives, thus allowing you to store far more photos.

Best use for JPG: JPG files are preferred for sharing on social media, sending by email, etc.

Primary disadvantage of JPG: JPGs are lossy, meaning the files are compressed. Losing that information limits what you can do to the image in post-processing.

Challenge Activity

To get a feel for the differences between RAW and JPG, capture an image in both formats. Using image editing software, perform a side-by-side comparison of the file sizes and the quality of the images.

Step 1: Visit your favorite location with a tripod-mounted camera and shoot a series of well-exposed images, saving them in both RAW and JPG formats. Use your camera’s dual save setting if available; otherwise shoot each image twice, changing the file setting between exposures.

Step 2: Obtain a software program that will open both formats. If you purchased your camera new, it’s likely that it came with a program on CD to edit files. You may also want to search the manufacturer’s site for downloads. If necessary, download a freeware editor or a trial version of Adobe Photoshop or Lightroom with Adobe Camera RAW.

Step 3: Download the files to your computer and compare the file sizes (the RAW file will have an extension like .CR2, .DCR, .DNG, etc.). Then, open both files in the editing software you chose. Remember that the RAW file may seem drab and flat, as no adjustments will have been made. Work with the editor to adjust the RAW file to your liking. Note the different formats that you can export the file to. Then work with the JPG file and note the limited range of adjustment to contrast, brightness, colors, etc. while maintaining quality.