The outer barrel is constructed of TSC (Thermally Stable Composite), which has a similar thermal expansion rate to aluminium. This means the metal inner barrel and the TSC outer barrel behave in a similar way as temperatures change, ensuring a consistent performance in all environments. Both materials are very light, with the lens weighing just 670g (L-Mount version). As with all Sigma lenses, the 50mm F1.4 DG DN | Art is crafted using cutting-edge manufacturing technology at Sigma’s sole factory in Aizu in Japan. Every single lens is evaluated with Sigma’s proprietary MTF measuring system before leaving the factory, ensuring consistenly excellent products that photographers can rely on. Advanced feature-set designed for professional use The lens barrel is equipped with a range of useful functions. As well as a manual aperture ring, the lens has an Aperture Ring Click switch, which allows users to switch between stepped, third-stop aperture increments and a smooth, click-free action. This is particularly useful for videographers who may want to use the aperture to adjust exposure seamlessly while filming. The aperture ring can be locked with lock switch. The lens has an AFL button, which can be customised to perform a range of different functions (depending on camera model). Also on the lens barrel is an Focus Mode switch, a rubberised focus ring with a smooth, fluid-like movement, and a robust, petal-type lens hood with lock button. The hood also has a rubberised grip for easy attachment and removal. Feature summary • Lens construction: 14 elements in 11 groups, with 1 SLD and 3 aspherical elements • Internal focus system • Compatible with high-speed autofocus • HLA (High-response Linear Actuator) AF motor • Compatible with Lens Aberration Correction Function available on supported cameras only. Available corrections and auto correction functionality may vary depending on the camera model. On cameras where lens aberration correction is controlled with ‘ON’ or ‘OFF’ in the camera menu, please set all aberration correction functions to ‘ON’ (AUTO). • Support for DMF and AF+MF • Compatible with AF Assist (Sony E-mount only) • Super Multi-Layer Coating • Water- and oil-repellent coating (front element) • AFL Button Only on compatible cameras. Available functions may vary depending on the camera used. • Support for switching between linear and non-linear focus ring settings (L-Mount only) • Aperture Ring • Aperture Ring De-click Switch • Aperture Ring Lock Switch • Dust- and splash-resistant structure • Petal type lens hood with lock (LH782-02) • Compatible with SIGMA USB DOCK UD-11 (sold separately; L-Mount only) • Focus Mode switch • Designed to minimise flare and ghosting • 11-blade rounded diaphragm • High-precision, durable brass bayonet mount • ‘Made in Japan’ craftsmanship • Every single lens is evaluated with Sigma’s proprietary MTF measuring system
