Although JPEG is the overwhelmingly popular choice for digital photo compression, there are several other options available that offer better image quality at the expense of higher file sizes.
Digital Photo Formats
The format of a digital photo depends on the type of compression used to store the image file. The letter at the end of the file name of a digital photo, something like ".jpg" or ".tiff" indicates the format in which your file has been saved. There have been numerous file formats throughout the history of digital photography but only a few have become the standard. The difference between the formats has to do with compression.What is digital photo compression?
Compression is how digital device like computers and cameras reduce the size of a file by removing information that is unlikely to be noticed by the naked eye. Fine details and subtle gradations will be lost during compression and these changes will only be visible under strong magnification. Compression is required to make the size of digital photo files small enough for practical uses. More digital photos can be stored on a storage device when the size of each file is smaller.What are common digital photo formats?
JPEG, which stands for Joint Photographic Experts Group, has become the industry standard for digital photo compression. Indicated by the .jpg file extension, JPEG achieves about 10 to 1 compression without much perceivable loss in image quality, making it ideal for digital photos. Most compact digital cameras offer only JPEG format for digital photo output, but more advanced cameras offer other choices like RAW and TIFF, which have their own advantages and disadvantages.File Sizes and Digital Photo Formats
A typical 5 megapixel digital photo in JPEG format takes up about 2 MB on a memory card or hard drive. This means about 500 such photos can be stored on a 1 GB memory card. In comparison, a similar digital photo stored in the RAW format takes anywhere between 30-40 MB of space, meaning only 25 such photos can be stored on a 1 GB memory card. This difference in file size makes JPEG the popular choice for most consumers.Disadvantage of the JPEG file format
JPEG looses quality each time a digital photo is edited or saved. This loss is a result of the compression used for JPEG digital photos. Therefore it is important to save a master copy of a digital photo and edit copies of that file. Alternatively, ‘lossless’ compression formats such as TIFF prevents quality degradation due to edits and saves. Advanced digital cameras allow photos to be saved in these formats right off the camera, or digital photo editing software can be used to convert JPEG formats to TIFF or RAW.RAW and TIFF digital photo formats
RAW is the format for digital photos where absolutely no compression has been applied, meaning it preserves every bit of information captured by the image sensor of the digital camera used. With the obvious downside that file sizes can be massive for digital photos stored in the RAW format, it is the purest form available for digital photographs. Furthermore, a RAW image has to be saved in another format such as JPEG or TIFF once it has been edited or manipulated.TIFF retains almost as much information as RAW, but is much smaller and allows for easy editing using software. TIFF is also good for retaining color information. Typical file sizes for TIFF digital photo files are in the 4 to 10 MB range compared to the 30 to 40 MB range for the RAW format.
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