As anyone with a digital camera knows, pictures are saved as files on a memory card. They can then be downloaded and printed. Some of the higher end digital cameras, however, have an option of saving the pictures in two different file formats: JPEG or RAW.
Both formats are completely different. One can easily be used by many different systems and applications, while the other is proprietary and needs to be converted first. One is compressed, while the other isn’t (although some say it can be). One is result of processing performed by the camera, while no processing is performed to get the other. As you can see the two formats are completely different, and yet there is a great debate on which format to use.
This purpose of this article is to discuss the differences to help you make a decision on which one fits better with our needs.
JPEG
The famous JPEG (Joint Photographic Experts Group) file format is beyond a doubt the most common digital camera file format. This format is used by all digital cameras, and can easily be downloaded and printed. It has the ability to compress images with 24 bits of colour data (8 bits each for red, green, and blue), or 16.7 million colours. This is more than enough colours to produce photo-quality images.
A JPEG file is also compressed, and uses a lossy compression. A lossy compression discards some data when in compresses an image. Usually applications, or in this case a digital camera, have a method of controlling the amount of compression applied to the image. The less compression applied to the picture, the better it looks, but the larger the size. If the compression is set too high, JPEG compression artifacts may appear in the picture. These can be seen as irregularities in the picture.
The JPEG format is very popular for posting images to the World Wide Web, or to send in an e-mail.
RAW
This format can be found in higher end digital cameras, such as DSLRs. Unlike the JPEG this format can’t just be downloaded and printed without first processing and saving the picture into another format. A RAW file is a proprietary format which is unique to each camera maker. This causes problems as vendor applications that provide the ability to edit RAW files must update their application to accept any new camera RAW formats. Usually, however, a camera will also include software that can edit the RAW format.
The RAW file is unprocessed data from the camera, meaning it is exactly what the camera’s CCD sees. No in-camera sharpening, contrast, or white balance settings are applied to the file before being saved to the memory card. This provides the flexibility of being able to set these settings manually after downloading the file to a computer.
While a JPEG file is 24 bits total, a RAW file stores up to 48 bits (16 bits each for red, green, blue). This provides more room for correcting the colour when processing the image on a computer.
It is important to note that many of the DSLR cameras also have the option of saving both a JPEG and RAW file of the same image. The downside to this is that it will use up more memory since you will be saving two images instead of one.
Comparison
| Item | JPEG | RAW |
|---|---|---|
| File Size | Small. Depends on the compression. | Large. |
| Compatible | Can be used by any photo editor and Web browser. | Limited to specific photo editors that support the format for the camera. |
| Compression | Lossy | None, but if used the compression is non-lossy. |
| Printing | Can be printed right from the camera. | Needs to be edited and saved to another format first before printing. |
| Colour Bits | 24bit (8 bits red, green, blue). | Up to 48 bits (16 bits red, green, blue). |
| Editing Ability | Can be edited but not too much or banding may occur. Should not be saved too many times or artifacts will become worse. | Can be edited many times before banding occurs. Should save to a standard non-compressed format such as TIFF when editing. |
| Processing Time | None. Can be printed from camera. | Much. Must be edited (sharpened, colour balanced) and saved to another format first before printing. Could use automation and bulk-editing to reduce the time. |
Summary
Determining which format to use depends on your photo editing skills. If you enjoy editing photos, and have a powerful computer then you may want to choose the RAW format. If you don’t feel like sitting in front of a computer and edit a photo, or can’t wait to print your photographs, then choose JPEG. In the end, it’s really a personal preference.