Illustrates how to fix geometric and perspectival distortion using Nikon’s free software Capture NX-D
Correct perspectival distortion in Nikon’s free software
The edge of a photo may bulge (or barrel) slightly as it is distorted by the lens. This type of geometric distortion is especially noticeable when shooting with a wide-angle lens, but most lenses will produce some barrelling. Depending on the quality of the lens your shots may also suffer from chromatic aberration. This manifests itself as green or purple fringes of colour clinging to contrasting objects. You may also notice the edges of a photo are darker than the rest of the frame due to vignetting, caused by different light levels entering the edge.
If you shoot a tall building from a low angle then you’ll notice that the vertical walls converge inwards towards the top of the frame. Capture NX-D can counteract this perspectival distortion and make verticals run parallel with the edge of the frame, even when working with JPEG files.
If you shoot in a Nikon Raw format, such as NEF, then you can counteract geometric distortion, vignetting and colour fringing in a few clicks by using Capture NX-D’S Camera and Lens Correction panel. Capture NX-D can read a Raw file’s metadata, determine which lens was used and then tweak the photo accordingly to counteract any fringing or barrelling. This level of control is one of the many reasons why you should shoot in Raw.