I've just bought the
DxO Labs Optics Pro software.
It is not a trivial purchase, but the price is reasonable considering how much I'm willing to pay for a good lens and the fact that this software magically improves the quality of images coming from a host of lenses and cameras.
In one automatic flow it improves noise, sharpness, and often color. And then the special bit: they have carefully tested a lot of popular lenses and cameras, and programmed the distortions of them into the software, so it corrects for that
specific camera, with that
specific lens, at that
specific zoom setting!
Here is a test on a picture I otherwise was very happy with, taken with a very good lens.
Before:
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After:
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With comparison it is clear that there is improvements in vignetting, sharpness/contrast, and distortion (lines are straight now).
(Some changes are less than obvious in the sizes and compression necessary for the Web.)
Before:
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After: