Canon EOS-1DX Instruction Manual page 296

R Processing RAW Images with the Camera
Chromatic aberration correction
When [Enable] is set, the lens' chromatic aberrations (color fringing
along the subject's outline) can be corrected. If [Enable] is set, the
corrected image will be displayed. If the effect is difficult to discern,
press the <u> button to magnify the image. (Press the <u> button
again to return to the normal view.)
About peripheral illumination correction, distortion
correction, and chromatic aberration correction
To execute peripheral illumination correction, distortion correction, and
chromatic aberration correction with the camera, the data of the lens used
for the shot must be registered in the camera. If the lens data has not been
registered in the camera, use EOS Utility (provided software, p.426) to
register the lens data.
Processing RAW images in the camera will not produce the same results as
processing RAW images with Digital Photo Professional.
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