Part 5 Rod Lawton reveals NX-D’s aberration-fixing tools
Sort out chromatic aberrations and barrel or pincushion distortion caused by your lenses using Nikon Capture NX-D
As regular readers of N-Photo’s lab tests will know, all lenses produce aberrations of one kind of another.
These fall into three general categories: distortion, vignetting (corner shading) and chromatic aberration (colour fringing).
Distortion is the most obvious, and it comes in two types. You often see ‘barrel’ distortion in wide-angle shots, where lines near the edge of the frame bow outwards. You can see this in the horizon line in our main shot, above. Telephoto lenses often show ‘pincushion’ distortion. Here, straight lines appear to bow inwards, not outwards.
Vignetting happens when the lens can’t maintain the same levels of illumination in the corners as it does in the centre of the picture. It often goes unnoticed, especially in shots like ours, where the edges of the picture are further from the sunset and are darker in real life. In some shots, though, you will want to remove annoying corner shading.
Chromatic aberration is the colour fringing effect you sometimes get around objects near the edges of the picture. The more expensive the lens, the less chromatic aberration you can expect to see, but most lenses suffer from it to one degree or another.
It’s very difficult, and expensive, to design lenses that don’t suffer from these flaws, but they can now be fixed digitally, which is a lot cheaper. And if you’re using Nikon lenses, it’s even easier because current Nikon D-SLRs have lens distortion correction built in, though you will need to activate this via the Setup menu.
Your Nikon can also correct chromatic aberration in-camera, though this and distortion correction can only be applied to JPEGs. The good news is, though, that if you shoot RAW files you can apply the same corrections in Nikon Capture NX-D. Here’s how…