Conclusion: 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.
Pros: High image quality - decently sharp from centre to corner even wide open, Extremely low distortion, Essentially no falloff/vigmetting, Small and lightweight
Cons: Moderate chromatic aberration (although not excessive for an ultra-wide)
Olympus M.Zuiko Digital 9-18mm f/4-5.6 ED - Review / Test Report
15 June 2010
Conclusion: The Olympus M.Zuiko 9-18mm f/4-5.6 ED is an engineering masterpiece. It is the most compact and light-weight ultra wide angle lens that we've reviewed to date. It is easy to use despite its small size and rather unusual retractable design.