Canon EOS 90D DSLR Camera with 18-135mm Lens - Manual (Page 210)

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Correction of Lens Aberrations due to Optical Characteristics
General Cautions for Lens Aberration Correction
o Peripheral illumination correction, chromatic aberration correction, distortion
correction, and diff raction correction cannot be applied to JPEG images
already taken.
o When using a non-Canon lens, setting the corrections to [Disable] is
recommended even if [Correction data available] is displayed.
o Magnifying the periphery of the image may display parts of the image that will
not be recorded.
o The correction amount will be less (except for diff raction correction) if the lens
used does not have distance information.
General Notes for Lens Aberration Correction
o The eff ect of the lens aberration correction varies depending on the lens used
and shooting conditions. Also, the eff ect may be diffi cult to discern depending
on the lens used, shooting conditions, etc.
o If the correction is diffi cult to discern, magnifying and checking the image after
shooting is recommended.
o Corrections can be applied even when an extender or life-size converter is
attached.
o If the correction data for the attached lens is not registered to the camera, the
result will be the same as when the correction is set to [Disable] (except for
diff raction correction).
o If necessary, refer to the EOS Utility Instruction Manual as well.