What are RAW images?

    22-Nov-2007
    8000786701

    Category : Shooting Images
    Description : What are RAW images?
    Using RAW images
     
    What are RAW images?
     
    RAW is the name given to an image file type that records image data captured by the camera's image sensor without any processing; it takes the name "RAW" because the data is raw. RAW images have the characteristic that the file sizes are larger than those of JPEG files. When handling the RAW images on a computer, use special applications for RAW images.
    When recording JPEG images used with most digital cameras, the image data is processed in the camera to adjust image quality to a suitable level so that it can be used right after being imported to the computer. However, because JPEG data deteriorates whenever it is edited and saved, repeating those functions will cause a loss of image quality.
    In contrast, RAW images need to be processed by special software before they can be manipulated with image-editing software. In this case, there is no deterioration of image quality when images are saved, so you can edit and save the images multiple times until you are satisfied with them. RAW images taken with your camera appear on the computer as files with a [.CR2] extension.
    Attention: Settings cannot be made for direct printing or DPOF prints when using RAW images.
    However, direct print and DPOF print settings can be made for JPEG images if the camera is set to record in both RAW and JPEG images simultaneously.


    Using sRAW images
     
    Your camera can be set to either RAW or sRAW (small RAW) when recording RAW images. sRAW images are RAW images that are one-fourth (approx5.2 megapixels) the size of a nomal RAW image. sRAW images can be handled in the same way as normal RAW images.
    The characteristics of RAW and sRAW are as follows.

    Type of Image quality
    Recorded pixels
    File Size
    (Approx. MB)
    Possible Shots
    (Approx.)
    Maximum burst (Approx.)
    Print size
    High-speed
    Low-speed
    RAW
    Approx. 21.0 megapixels (5616x3744)
    25.0
    75
    12 (12)
    14 (16)
    A2 or larger
    sRAW 
    Approx. 5.2 megapixels (2784x1856)
    14.5
    130
    18 (18)
    24 (28)
    Around A4

    - The number of possible shots and maximum burst apply to a 2GB CF card based on Canon's testing standards. Figures in parentheses apply to an Ultra DMA (UDMA) 2GB CF card based on Canon's testing standards.
    - The file size, number of possible shots, and maximum burst during continuous shooting are based on Canon's testing standards (JPEG quality: 8, ISO 100, Picture Style: Standard).


    Using RAW images on the computer
     
    Most image-editing software cannot display RAW images, so some processing is required to open them. "Processing" means converting the RAW images to an appropriate file type such as JPEG so that the file can be manipulated on the computer.
    When processing RAW images on a computer, the images will be converted in accordance with the settings (such as Picture Styles) specified in the camera at the time of shooting. Also, the images can be edited using image-editing software in addition to the parameter settings described above.
    Once a RAW image has been processed, a new file will be created in addition to the original RAW image. The modification only affects the newly created image so that you can keep the original RAW image. This enables you to repeat the processing until you are satisfied with the image.
     
    To process RAW images, you need to use Digital Photo Professional, ZoomBrowser EX (for Windows), or ImageBrowser (for Macintosh).
    The software to be used depends on the computers you are using and your intended use.
    For more information on each application, please refer to the supplied documentation.

    Software
    ZoomBrowser EX
    ImageBrowser
    Digital Photo Professional
    Supported OS
    Windows Vista (*)
    Windows XP Professional/
    Home Edition (SP2)
    Windows 2000 (SP4)
    Mac OS X(10.3~10.4)
    Windows : Windows Vista (*)、
    Windows XP Professional/
    Home Edition (SP2)
    Windows 2000 (SP4)
    Macintosh : Mac OS X(10.3~10.4)
    Purpose
    Displaying or editing RAW images imported to the computer via EOS Utility. Also, when using other supplied software, it is possible to stitch multiple images together or use other various functions.
    Editing RAW images imported to the computer. With this software, you can edit more widely than when using ZoomBrowser EX or ImageBrowser.
    * Compatible with 32-bit/64-bit systems for all versions except Starter Edition.