Canon EF 20mm f/2.8 USM - Full Format Review / Test
21 May 2008
Conclusion: The Canon EF 20mm f/2.8 USM is not a bad lens but it shows that its design dates back to the early 90s. The technical resolution is actually pretty good with a very sharp image center and pretty good borders. The corners are also very decent at medium aperture settings. However, the lens suffers from a high degree of field curvature unless you adjust your shooting style you will end with relatively soft outer image region.