Distortion is very dependent on focusing distance as well as aperture. But as all details are recorded in the actual shoot the automatic correction can be applied just by the click of a button.
Even though that both the corrected and the un-corrected looks fine you will find that the barrel effect is removed by turning the correction on. At some images this in-significant and sometimes you might even prefer that effect, but generally it is a minor optical error, which we by default assume that no one is missing.
© Photo: Anders Espersen