When distortion control is applied to an image either in-camera or through software it corrects barrel or pin cushion distortion that occurs in images due to the characteristics of specific lenses.
This tends to affect images shot with wide angle lenses and results in an image that appears to bow outwards from the centre of the image.
Pin cushion distortion
This is more often associated with images shot with telephoto lenses and results in the image appearing as though it is being pulled towards the centre.
Pin cushion Distortion
Applying Distortion Control Data In-Camera
Distortion control can be applied to images during shooting by setting Shooting Menu > Auto Distortion Control > On or after shooting in the cameras Retouch Menu > Auto or Manual. Images will be cropped in this process. With the Auto option the camera will read data from the lens being used and the focal length selected and makes adjustments automatically.
The Distortion Control data in camera can be updated to include data for the latest lenses from the Download Centre . Please ensure the cameras firmware is updated first to support the latest version of Distortion Control Data. A list of compatible lenses is available from the download pages.
With Manual Distortion Control in the Retouch Menu you can adjust the image with a fine-tuning slider. The degree of fine-tuning applied varies in relation to the lens used. If the lens exhibits large amounts of barrel or pin cushion distortion then the amount of change that can be applied is greater than on a lens exhibiting very little distortion. The fine tuning is limited as the cursor can only move in steps and can result in slight over or under compensation. Once an adjustment has been made you will have the option to save it and this produces a copy of the original.
Applying Distortion Control Data in Software
Distortion can also be corrected in Capture NX-D or Capture NX 2 software. The image is still cropped in this mode. In Capture NX-D there is a simple check box which you can tick and the Distortion Control is automatically applied. With Capture NX 2 there is also an Auto option through the Edit List > Camera and Lens Correction Menu or there is a Manual option through the Adjust > Correct > Distortion Control option. The manual option allows you to choose a fill-colour for the background to make it easier to see what areas in the image you will lose when the image is cropped and offers fine control with the Correction slider.