The Canon RF mount has been limited in its lens options, particularly for APS-C users. If you've found yourself frustrated with the lack of fast, versatile lenses for Canon’s APS-C mirrorless cameras, you're not alone. However, there's good news. Canon is finally allowing third-party manufacturers to develop for the RF mount, and Sigma's 18-50mm f/2.8 DC DN Contemporary lens is a standout in this new lineup.