Canon EOS-1D X Mark III Advanced User's Manual page 610

4.
Select the type of images to transfer.
RAW+JPEG transfer
• Select [RAW+JPEG transfer], then select [JPEG only], [RAW
only], or [RAW+JPEG].
RAW+HEIF transfer
• Select [RAW+HEIF transfer], then select [HEIF only], [RAW only],
or [RAW+HEIF].
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