Article ID : 00024656 / Last Modified : 02/09/2023Print

What is a RAW image file and how much memory does it require?

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    RAW files are image files that contain uncompressed and unprocessed image data, allowing you to capture practically every detail seen from the camera image sensor.

    Some characteristics of RAW files:

    • RAW files require more memory storage than JPEG, PNG, BMP, and TIFF files, and a program must be used to open and edit the files.
    • RAW images taken with Sony cameras are saved with the ARW extension.
    • Provides the most detailed image a camera can offer.
    • Contains millions of colors, increased RGB color values and allows adjustments to the RAW file without changing the image itself.

    Digital cameras generally perform digital processing to the output signals from the image sensor and create JPEG images. Meanwhile, RAW is an image format whose processing parameters can be adjusted freely by photographers, so there is no digital processing done on the image.  It is transferred directly from the image sensor to the storage medium of the camera.


    • RAW file size information (file size can vary depending on shooting settings).
      • File size information for RAW files taken with a full-frame camera:
        • Uncompressed → 100 MB
        • Lossless compression → 62 MB
        • Compressed → 52 MB
      • File size information for RAW files taken with an APS-C camera:
        • Uncompressed → 43 MB
        • Lossless compression → 30 MB
        • Compressed → 22 MB
    • Lossless compression allows slight reductions of the memory required with no loss of image information.
    • After a firmware update, the ILCE-1 camera allows the selection of small, medium, and large sizes when using the RAW lossless recording method.