RAW and JPEG
The buffering concerns are only likely to be a real issue for professionals and those who regularly shoot sequences of photographs in quick succession in RAW format. There continues to be debate and plenty of misinformation over which format you should shoot. JPEG is basically a compressed method of storing data that results in some loss of quality. RAW files, conversely, often referred to as a digital negative; retain all of the information exactly as it was recorded to the camera image sensor when you pressed the shutter without any processing done by the camera. Many professionals prefer to shoot in RAW format because it provides far more control over the final appearance of the image by allowing many changes to be made. RAW files are very large, greatly reducing the number of images that will fit onto your digital film card. They also take up a vast amount of hard drive space when loaded to your computer and specific image editing programmes (such as Adobe Photoshop) are required to view and work on the files. JPEG files can only be minimally modified using editing software but they can be viewed and utilised immediately to print, burn onto CD or send as an e-mail attachment. Because JPEGs are easy to use and still can retain excellent resolution, it is perfectly acceptable to shoot images using this format. Most cameras will allow you to set the resolution level (fine, medium, and low for example) which determines the quality of the JPEGs captured. On most modern cameras, by shooting at the maximum resolution setting will produce almost ‘lossless’ images that are perfectly good for most applications. There is a slight compromise however. Unlike RAW files, JPEGs cannot be opened continuously and re-saved indefinitely without some element of quality being lost each time. One solution is to save the original files as RGB TIFFs through your photo editing software that can be retained as masters and then open and save a new copy as a JPEG whenever the need arises. Most may not notice any difference in the image quality of JPEGs but if the images that you produce have an archival content that is required for longevity, it is more sensible to create and save your images in RAW format.
It is worth considering the number of images that can be crammed onto a digital film card using different shooting resolution settings. Because RAW will be stored, as the name implies, in its raw form without any kind of file compression, your storage medium will hold far less images than those shot in JPEG format. The exact number will depend on the camera and the amount of data being recorded when you press the camera shutter. As an example, my Fuji Fine Pix S3 with a 2gb CF card will capture 78 images in RAW format (at the cameras highest resolution) compared to 1,868 images captured at the camera’s lowest setting of 1 million pixels; 1120 at 3 million pixels, 655 at 6 million and 413 images at 12 million pixel resolution. Quite a difference.
Finally, before buying your D-SLR it is always worth taking the time to study appropriate reviews in the photographic press and by visiting the camera maker’s own web sites where you can download brochures for the equipment that you are interested in buying.
