JPEG vs. Raw

The question of whether to use "Raw" or "JPEG" file formats is often discussed in my continuing education classes. I personally use the Nikon line of cameras but what follows is completely relevant with Canon, Kodak, etc. Virtually all modern DSLR cameras have the ability to shoot in Raw format, JPEG format, or both simultaneously. So what's the difference?

JPEG (created by the Joint Photographic Experts Group in 1992) is a form of image compression that digital cameras commonly make use of. For example, my Nikon D80 creates images that are approximately 7.5 megabytes when shooting in the largest JPEG format (Fine). Comparatively, when I shoot in Raw, my images are approximately 12 megabytes. The JPEG format compresses my images by approximately 30 to 40% compared to Raw. This increase in memory card performance is certainly a plus. However, the benefits may exceed the costs.

The JPEG file format has two major limitations in my opinion.

1) Generational Loss
Every time you open and close a JPEG image you lose small pieces of data. The extreme compression the JPEG format uses causes bits and pieces of your image to literally disappear. To this end, I would recommend saving any image you care about as a Tiff or PNG format. These are considered lossless image formats and won't degrade with continuous editing.

2) Extremes, Shadows, Highlights
The JPEG format has difficulty recording detail in extreme lighting conditions. Observe the following two photographs.

(Above) Toast shot as a JPEG in extreme sunlight with a poor exposure. The image was edited in Photoshop Elements. I tweaked Levels and burned the hot spots in. This was as good as it gets.


(Above) Same image taken in RAW format. Same exposure as JPEG toast with the same Photoshop tweaks.

While this is not my favorite photograph, the above is pretty stunning. Raw formats are vastly better at recording the image with as much detail as your camera's sensor can manage. This makes post processing in Picasa or Photoshop vastly easier. My recommendation is to use whatever Raw format your camera provides. Picasa 3 and modern versions of Photoshop will have Raw support built right in.