Sigma 18-35mm f/1.8 DC HSM Art Lens for Nikon Bundle Includes Metabones Nikon G to Micro Four Thirds Speed Booster + Manufacturer Accessories + 3PC Filter Kit + Microfiber Cleaning Cloth SIGMA 18-35 F/1.8 - Aperture Range: f/1.8-16; Fast Constant Maximum Aperture; Four Aspherical & 5 SLD Glass Elements Designed for APS-C-Sized Sensors 35mm; 35mm Equivalent Focal Length: 27-52.5mm Hyper Sonic AF Motor; Internal Focusing and Zoom Design; Super Multi-Layer Coating Metabones Speed Booster XL 0.64x Adapter for Nikon F-Mount Lens to Select Micro Four Thirds-Mount Cameras; 1.3-Stop Increase in Lens Apertures 0.64x Micro 4/3 Crop Factor Compensation; 6 Optical Elements in 4 Groups; Locking Mechanism to Secure Lens; Brass Mounting Rings