Typically, moderately priced zoom lenses show some perspective distortion towards the ends of its focal range. Distortion is generally most problematic, however, at wide-angle settings. This held true with the two Micro Four Thirds kit lenses; Panasonic and Olympus’s optics both display significantly more aberration when zoomed out to their widest, 14mm setting (which roughly equates to a 28mm view on a 35mm camera).
Distortion can show as a bending or bowing of lines, and moves in two directions: it can look as if the corners of the image are being pulled outward (barrel distortion), or as if the edges are being pushed inward, towards the center of the frame (pincushion distortion).
Shooting the two Micro Four Thirds lenses at their widest focal length -- 14mm on both -- we detected 9.79% distortion from the Panasonic Vario lens, with 12.40% distortion in the shot from the Olympus M.Zuiko lens. The image from the Panasonic lens showed lines more squarely, though the difference when we viewed prints side-by-side was not extreme.
Zooming in on our test target, the Panasonic Micro Four Thirds kit lens maintained virtually perfect lines at full telephoto, showing less than 1 percent (.75%) distortion at 45mm. Olympus’s M.Zuiko kit lens is slightly shorter than Panasonic’s counterpart -- extending to 42mm at full telephoto – though it nonetheless showed significantly more distortion at full zoom. The shot from the Olympus kit lens at 42mm contained 4.24% distortion.