One thing you hear a lot about today is discussion about shooting pictures in JPEG (pronounced jay-peg) or RAW format (if your camera has that ability). Well, like many photographers, I have an opinion. But first, the technical definition.
JPEG - (Joint Photographic Experts Group) is a standard for compressing still images. The JPEG format is very popular due to its variable compression range. JPEGs are saved on a sliding resolution scale based on the quality desired. For example, an image can be saved in high quality for photo printing, in medium quality for the Web and in low quality for attaching to e-mails, the latter providing the smallest file size for fastest transmission over dial-up connections.
Not Great for Text
JPEGs are not suitable for graphs, charts and explanatory illustrations because the text appears fuzzy, especially at low resolutions. Compressing images in the GIF format is much better for such material.
JPEGs Are Lossy
Using discrete cosine transform, JPEG is a lossy compression method, wherein some data from the original image is lost. It depends on the image, but ratios of 10:1 to 20:1 may provide little noticeable loss. The more the loss can be tolerated, the more the image can be compressed.
Compression is achieved by dividing the picture into tiny pixel blocks, which are halved over and over until the desired amount of compression is achieved. JPEGs can be created in software or hardware, the latter providing sufficient speed for real time, on-the-fly compression.
RAW format images, on the other hand, do not typically compress the data and none of it is lost. So, here’s where my opinion comes in. Many will tell you that it’s fine to shoot in JPEG all the time because who’s going to blow something up large enough for you to notice if you are using the JPEG versus RAW? My response to that is: Why let your camera, some obscure algorithm or anyone else randomly decide which data stays and which is thrown out? Why decide what your maximum print image size is going to be before you even take the file off your camera and put it on the computer?
If space is not an issue on your memory card, I recommend that you ALWAYS shoot in RAW if your camera has that setting. If it doesn’t have a RAW setting, then make sure you are shooting with the largest JPEG (least compression possible) setting. Don’t start your photo session by taking an image that is not at the maximum capability of your camera if you can afford to. Those of us who do the ‘post processing’ of your image will thank you for that extra data when it comes time to make those wall sized ‘art’ prints on canvas.
Landscape and portrait photographer, David E. Warner captures the breath-taking beauty of the Mohawk Valley and Southern Adirondacks region and its people with his mastery of color, composition & light. He shuttles between upstate New York and Texas for part of the year - working on portrait and film projects.
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