Canon EF 16-35mm f/2.8L III USM Lens

High performance L-series ultra-wide-angle zoom lens with constant f/2.8 maximum aperture. All-new optical design for significant improvements in outer and corner sharpness. Sub wave length Coating (SWC) and Air Sphere Coating (ASC) help to significantly reduce flare and ghosting. Highly resistant to dust and water intrusion, enabling shooting even in harsh conditions. Circular aperture (9 blades) helps deliver beautiful, soft backgrounds. Not an Extender Compatiblity. Magnification with Extension Tube EF12 II- 0.65 at Tele (Not compatible at Wide). Magnification with Extension Tube EF25 II- 1.14 at Tele (Not compatible at Wide).Lens Construction:16 elements in 12 groups.Filter Size: 82 millimeter, P=0.75 millimeter: 1 filter