A Viewfinder Darkly
Phil Northeast is Feature Writer for Photography at 
Stock photography by Phil Northeast is available from Ozimages International
Photography Formats Choosing RAW or JPEG
When to Use Each File Format In Your Digital Camera
Philip Northeast
Examining the advantages of the RAW file format for the best quality images or saving them as JPEGs to store more shots on the camera’s digital memory card.
Photographers with high performance digital cameras can choose the file format the camera uses to store the images on the memory card, the common alternatives are RAW and JPEG.
RAW
RAW is not really a file format, instead it refers to the file format used by each camera manufacturer where there is minimal in-camera processing of the image data. The camera saves unaltered, or raw, image data plus camera settings for the image such as white balance, sharpness, contrast and saturation.
coloured stage lighting can fool the
camera's auto white balance
The camera manufacturer usually supplies the software tools required to process their own version of a RAW file with their cameras. There are software suppliers who offer alternatives that promise better, faster or more convenient computer processing of RAW files. Either they can be stand-alone programs or as plug in extras to programs such as Photoshop. There is a move by Adobe to create a standardized RAW format, or Digital Negative (DNG).
The larger RAW file size offers the potential for more detail in the final image. While some camera models may have issues with Automatic White Balance (AWB) performance, the ease of adjustment of colour temperature while processing RAW images makes this the preferred option in difficult lighting situations.
For your best shots choose the RAW format and get more details, with minimal in camera processing. This allows greater scope for individual image adjustment on the computer, rather than accepting the preset in-camera adjustments. Also continuing advances in software promises better RAW file processing in the future. Because RAW files are uncompressed and contain more information than JPEG files, they require more storage space and take longer to transfer and transmit.
JPEG
JPEG (or jpg) comes from the Joint Photographers Expert Group and is very common storage option for nearly all digital cameras. The camera’s on-board computer takes the RAW data and applies preset image preferences, such as sharpness, saturation and contrast. Then the processed data is compressed and saved to the memory card as a JPEG file. The photographer can choose to use a range of JPEG sizes, the quality of the stored image getting worse the smaller the file. The advantage of smaller image size is that it allows more images on a memory card. The choice is how much quality is enough?
JPEGs are good for sports where lots of shots are taken
The smaller JPEG image files make better use of storage space and are quicker to send over the Internet. JPEG is the standard for the display of photographs on web pages, although these are usually smaller more compressed images. The best quality or least compressed JPEGs are a very usable image. For example, professional photographers use JPEGs to produce publishable images for newspapers and many magazines. Top quality JPEGs from DSLR’s are suitable for A4 size and larger prints.
Professionals choose the JPEG format when speed and storage capacity are an issue. It is possible to get three to four times as many high quality JPEG images onto a memory card than the uncompressed RAW format. This is an important consideration for a motor sports photographer, who may shoot thousands of images over a weekend race meeting. The smaller JPEG file size enables faster transfer and selecting of images to meet editorial deadlines for newspapers and Internet news sites. However, if you are shooting a spread for a glossy fashion magazine the choice is to use the RAW image data to ensure maximum quality.
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