Canon EOS 5D Mark IV L-series Standard Zoom Lens Kit Owner's Manual

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207
Peripheral light fall-off is a phenomenon that makes the image corners 
look darker due to the optical characteristics of the lens. Image 
distortion due to optical characteristics of the lens is called distortion. 
Color fringing along subject outlines is called chromatic aberration. And 
decreased image sharpness due to the aperture is called diffraction 
phenomenon. These lens aberrations can be corrected. The Digital 
Lens Optimizer can correct the various aberrations caused by optical 
characteristics of the lens, diffraction phenomenon, and the 
deterioration of resolution caused by the low-pass filter.
By default, the [Peripheral illum corr], [Chromatic aberr corr], and 
[Diffraction correction] are set to [Enable], [Distortion correction
and [Digital Lens Optimizer] is set to [Disable].
If the lens correction data is registered (saved) in the camera, 
peripheral illumination correction, chromatic aberration correction, and 
diffraction correction will be done even in the <A> mode.
If the setting screen displays [Correction data not available] or the 
[
] icon, it means that the correction data for the respective lens is not 
registered in the camera. See “Lens Correction Data” on page 213.
1
Select [Lens aberration 
correction].
 
Under the [z1] tab, select [Lens 
aberration correction
], then press 
<0>.
2
Select [Peripheral illum corr].
3
 Correction of Lens Aberrations due 
to Optical CharacteristicsN
Peripheral Illumination Correction