Almost all lenses suffer from aberrations, including distortion, chromatic aberration and vignetting. These are difficult to eliminate optically in the lens design, so software publishers are increasingly offering lens correction profiles to do this digitally. The software can identify the lens used from the image’s EXIF data and then find and apply the correct profile automatically.
Lens aberrations explained
No camera lens is optically perfect. In order to offer the focal lengths, zoom ranges, maximum apertures, sizes or prices that people want, the designers have to make some compromises. This means that all lenses exhibit 'aberrations' to some degree. Typically this may involve distortion, where straight lines start to appear bowed, chromatic aberration, or colour fringing, around object edges, and corner shading or vignetting, where the edges or corners of a picture are darker than the centre.
Here's a selection of topics explaining a little more about aberrations and what lens designers can do about them.
A processing algorithm used by Fuji in some of its cameras to counteract the softening effects of diffraction at small lens apertures, and image softness at the edge of the frame. It seems likely the LMO is simply applying some intelligent sharpening.
Lenses aren’t perfect – they all have optical aberrations of one sort or another. Now, though, many software applications have lens correction to correct these digitally, either with manual controls or automatic lens correction profiles.
An optical effect in some lenses where straight lines come out slightly bowed. You often see ‘barrel distortion’ with wideangle lenses or ‘pincushion distortion’ with telephoto lenses at their longest zoom setting. More expensive lenses tend to have less distortion but, generally, the longer the lens’s zoom range the more likely you are to see distortion creeping in.
This is a lens aberration that produces colour fringing around the outlines of objects near the edges of the picture. It’s very hard to eradicate completely from lens designs without making them extremely complex or expensive, but it is possible to correct chromatic aberration using software and many cameras will now correct it automatically as they process the image.