The Zuiko Digital ED 9-18mm 1:4-5.6 is without doubt a very good lens indeed, especially for a relatively inexpensive ultra-wideangle zoom. It's sharp even wide open, has negligible distortion, and shows practically no vignetting.

High image quality - decently sharp from centre to corner even wide open; Extremely low distortion; Essentially no falloff/vigmetting; Small and lightweight

Moderate chromatic aberration (although not excessive for an ultra-wide

High image quality - decently sharp from centre to corner even wide open; Extremely low distortion; Essentially no falloff/vigmetting; Small and lightweight;

Moderate chromatic aberration (although not excessive for an ultra-wide);