A member of the high-performance Contemporary line, featuring Sigma's latest technologiesSmooth Af ideal for video shootingThe combination of optical design for video Af and use of the stepping motor enables smooth and quiet autofocus. This lens is also compatible with the Sony E-mount Fast Hybrid Af, achieving precise Af tracking. By using the face recognition or eye Af functions of cameras, focus will continuously be on the face or the eye even if the subject moves during the shoot.High-precision, rugged brass bayonet mountThe brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens.Mount with Dust and Splash Resistant StructureThe mount features a special sealing to make the lens an excellent choice in a wide variety of conditions.