Digital File Formats Explained
JPG, TIFF, RAW
The reason for the array of file types is the need for compression. Image files can be quite large, and a larger file type means more disk usage and slower downloads. Compression is a term used to describe ways of cutting the size of the file.
The file types
JPG is optimized for photographs and similar continuous tone images that contain many, many colors. JPG achieves amazing compression ratios while maintaining high image quality. JPG works by analyzing images and discarding kinds of information that the eye is least likely to notice. It stores information as 24 bit color. Important: the degree of compression of JPG is adjustable. At moderate compression levels of photographic images, it is very difficult for the eye to discern any difference from the original, even at extreme magnification. Compression factors of more than 20 are often quite acceptable. Better graphics programs, such as Paint Shop Pro and Photoshop, allow you to view the image quality and file size as a function of compression level, so that you can conveniently choose the balance between quality and file size.
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RAW known as a "digital negative", the RAW format was developed by camera manufacturers that realized there were still photographers out there who wanted more control on how the final picture would be.
RAW format is often praised for having the most information to generate an image file. Just like how a photo print can be developed from a negative, a RAW file can be processed to become a digital image.
While JPEG and TIFF may contain changes made by the camera to suit the image, a RAW file is uncooked and you can fine-tune it until the desirable result is achieved. In harsh lighting conditions, certain highlights and shadows in your image may be lost if you shoot in JPEG or TIFF. However, with RAW, if the exposure is correct you can actually retrieve these details back by making adjustments.
RAW format are more commonly found in dSLRs, though recently it has made its way into prosumer models. Although larger in file size then a JPEG, a RAW file is still considerably smaller then a TIFF.
One thing to note is that each camera manufacturer has its own RAW format. For Canon, it is .CRW and for Nikon it is .NEF. Therefore, you will need the software supplied by them to view and edit your pictures. If you want to share these images, you'll have to "process" the RAW file to a more common file format.
Strictly for the purist, you may find RAW daunting to handle at first, but you'll appreciate the control you have on the resulting image.
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TIFF (Tagged Image File Format)
Although this format is less commonly found in digital cameras, it is still offered in higher-end models.
This format is slowly being dropped by camera manufacturers as it takes up a lot of space in the memory media. Compared to a JPEG file of the same pixel dimension, the TIFF file can be 10 times bigger in file size. Since the quality of JPEG images is getting better, TIFF may soon become obsolete in digital cameras.
A redeeming factor for TIFF is that it applies loss less compression to your file when saving. Thus, you can get a richer, more detailed picture when shooting in TIFF.
Unless you are really fussy about image details and have a high-capacity memory media, TIFF files may take up too much space for storage.
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