Pairing an ultra-wide focal length with a bright maximum aperture, the Ultron 21mm f/1.8 from Voigtlander is a versatile lens designed for M-mount rangefinder cameras. Its expansive field of view is well-suited to architectural and interior subjects while the bright f/1.8 maximum aperture benefits working in low-light conditions. One aspherical element is featured in the optical design to help reduce spherical aberrations in order to produce greater sharpness and clarity throughout the aperture range. The lens also features a manual focus design, which permits working with subjects as close as 1.6' away, and it has a built-in lens hood to shield the front element and minimize lens flare and ghosting.