Nikon Soft­ware

Part 5 Rod Law­ton re­veals NX-D’s aber­ra­tion-fix­ing tools

NPhoto - - Contents -

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…

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