http://www.dpreview.com/lensreviews/olympus_50_2_o20/page4.asp

dpreview在評測ZD 50mm F2.0時有對Sigma 50mm F1.4做出一些比較

We expect many potential buyers will be interested in comparing the 50mm F2 Macro to the Sigma 50mm F1.4 EX DG HSM, which has been recently announced in Four Thirds mount. Our recent review of this lens (albeit in Canon EF mount) should give a good idea of what to expect; the Sigma is likely to be no slouch on Four Thirds, but unsurprisingly for a lens designed for a format with four times the area, won't quite achieve the same stellar levels of sharpness we see from the Olympus macro. The faster maximum aperture and more refined ring-type USM focusing will surely make the Sigma a compelling option for portrait shooters, but in all other regards the Zuiko is likely to be the better all-round option.