Canon EOS 70DN Basic Instruction Manual page 312

3 Lens Peripheral llumination / Chromatic Aberration Correction
Lens Correction Data
The camera already contains lens peripheral illumination correction
data and chromatic aberration correction data for approx. 25 lenses. If
you select [Enable], the peripheral illumination correction and
chromatic aberration correction will be applied automatically for any
lens whose correction data is registered in the camera.
With EOS Utility (provided software), you can check which lenses have
their correction data registered in the camera. You can also register the
correction data for unregistered lenses. For details, refer to the EOS
Utility Instruction Manual (p.459) on the Software Instruction Manual
CD-ROM.
Notes for Peripheral Illumination Correction and Chromatic Aberration
Correction
Peripheral illumination correction and chromatic aberration correction
cannot be applied to JPEG images already taken.
When using a non-Canon lens, setting the corrections to [Disable] is
recommended, even if [Correction data available] is displayed.
If you use magnified view during Live View shooting, the peripheral
illumination correction and chromatic aberration correction will not be
reflected in the image shown on the screen.
If he effect of the correction is not visible, magnify he image after
shooting and check it again.
Corrections can be applied even when an Extender or Life-size
Converter is attached.
If he 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].
If the lens does not have distance information, the correction amount will
be lower.
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