Essential Guide to Wideangle lenses
The disadvantage of using some wideangle lenses is that they can exhibit lens defects. Barrel distortion is a lens defect that causes straight lines to bow outwards at the edges of the frame.
Chromatic aberration is a colour fringe that can appear along high-contrast edges and vignetting refers to the edges of an image that appear darker than the centre. Although some wideangle lenses control these optical flaws better than others it's good to know how they're rectified in Adobe Camera Raw.
Head to the Lens Corrections filter, tick Enable Lens Profile Corrections and this will apply settings based on the camera, lens and focal length used. Any lens defects will then be automatically corrected, leaving you with an image that's less distorted than when you first started.