Conclusion: The Canon EF 50mm F1.4 USM may be based upon a 37-year old optical design, but its performance in our studio tests clearly shows that it's not giving up yet. Sure the hairs are beginning to grey a little, and Sigma's new young pretender can outmuscle it comprehensively at wider apertures, but this...
Pros: Excellent image quality when stopped down, Essentially no lateral chromatic aberration, Fast and accurate autofocus with full-time manual override
Cons: Distinctly soft and 'dreamy' at wider apertures (F1.4-F1.8), Bokeh chromatic aberration, most visible at wide apertures, Vignetting at wide apertures on full frame (essentially disappears by F2.8), Somwhat susceptible to flare
Conclusion: The Canon EF 50mm f/1.4 USM is a rather obvious choice when looking for a standard lens to be used on an Canon APS-C DSLR. That said it struggles a bit at maximum aperture - the borders are somewhat soft here, the contrast level is reduced and the amount of vignetting could be better.
Canon EF 50mm f/1.4 USM - Full Format Review / Lab Test Report
2 September 2009
Conclusion: It is no surprise that the Canon EF 50mm f/1.4 USM is a very popular choice among Canon users when it comes to choosing a standard lens. It offers probably the best compromise between quality and price here. That said it's not a flawless lens when used on a full format DSLR.