Canon EOS-1D X Manual (en)

Checkmark the [Digital Lens Optimizer] checkbox 
and adjust the image. 
Reverts to its condition 
before adjustment
Since the lens data downloaded with DPP version 3.x is not 
compatible with DPP version 4.x, the lens data must be downloaded 
When applying the Digital Lens Optimizer, the effect of [Sharpness] 
or [Unsharp mask] may become excessive. It is recommended that 
you set [Sharpness] or [Strength] for [Unsharp mask] for images to 0 
before using the Digital Lens Optimizer. Adjust [Sharpness] or 
[Unsharp mask] again after applying the Digital Lens Optimizer to 
You can also use this palette to adjust the image sharpness. For 
information on making adjustments, see “Adjusting Image Sharpness” in 
“Editing with the Basic Adjustment Tool Palette” 
Use the slider to adjust the Digital Lens Optimizer effect.
If no shooting distance information is saved to the image, the 
shooting distance slider is set automatically to the right end at 
infinity position and a [<!>] appears above the shooting distance 
Images cannot be corrected for [Chromatic aberration] in the lens 
aberration correction tool pallet if the Digital Lens Optimizer has 
been applied.
In the main window, the [
mark is displayed on the image to 
indicate that the Digital Lens Optimizer is applied
Adjusting Image Sharpness