Notes: Prime, Fast and Wide

Sigma's 20mm f1.4 Art Series lens is muse-worthy

Prime and fast. As a photographer, these are the two most important words that describe the lenses I use. Prime, meaning one focal length—not a zoom lens. Fast, meaning a wide aperture to let in lots of light. Prime lenses not only deliver sharper and crisper images, they also force me to think more about where to position my camera in space to get a …