Sigma AF 20mm f/1.8 EX DG RF (FX) - Review / Test Report
27 January 2009
Conclusion: Just like its slightly longer sister lenses, the Sigma AF 20mm f/1.8 EX DG leaves us with mixed feelings. The center resolution of the lens is very good to excellent, while the borders and corners disappoint especially at large apertures. Vignetting is very pronounced wide open.