This is an EF lens 300mm 2.8L IS USM Features Diagonal Angle of View: 8° 15' Lens Construction (elements/groups): 17/13 Closest Focusing Distance (m): 2.5 m / 8.2 ft. Focus adjustment: Inner focusing system with USM Filter Diameter (mm): 52 mm Rear Drop-in Especially popular with sports and wildlife photographers Successor of the EF300mm f/2.8L USM, this is a next-generation wide aperture 300mm lens with a newly designed optical system to achieve even better image quality. Its one fluorite lens and two UD lenses completely eliminate secondary spectrum. It offers super high image quality with both resolution and contrast higher than ever before. And the image stabilizer that equals about 2 shutter speed steps maximizes the performance of the lens under all photgraphy conditions. Its autofocusing is the fastest in the world (when used with an EOS-3), thanks to a ring USM and improved drive algorithm. Closest focusing distance has been reduced to 2.5m, while operatibility has been substantially improved by full time mechanical manual focus, improved focus preset, and the introduction of an AF Stop function. The lens's super light design includes a magnesium alloy lens barrel and it offers good dust-proof and moisture-proof performance even under harsh conditions. It comes with a removable tripod.