You can change the center of corrections to shading (peripheral dimming). This is especially effective when obtaining effects of dimming the four corners equally, even when trimming the photograph so that the center angle of view has been moved when the peripheral has been dimmed as an effect (when aiming for a tunneling effect).

peripheral Dimming after Trimming

If you are aiming for peripheral dimming effects, this can be applied to dimming effects equally in the four corners, even when the center of the image has been moved.

Peripheral Dimming after Trimming

Dimming effects of shading can be applied to the four corners equally even when the center of the trimming is moved when changing the aspect ratio due to trimming as shown in 1:1.