Sigma 50-100mm F/1.8

50-100mm F/1.8 Lens Highlights Features three FLD (F Low Dispersion) glass elements, one SLD (Special Low Dispersion) glass element, and one high-refractive index, high-dispersion glass element to minimize aberrations. Redesigned and enhanced, the new Hyper Sonic Motor is 30% slimmer and provides fast and accurate AF. Highly durable polycarbonate diaphragm made with fluorine; blades feature carbon feather film offering exceptionally smooth operation even during continuous shooting. Inner focusing and zoom design offer versatile shooting options Tripod socket for stable, comfortable operation Features 21 elements / 15 groups, Minimum Aperture: F1.8, 82mm filter thread, Minimum Focus Distance: 37.4in, Dimensions: 3.7×6.7, Weight: 52.6oz